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SHELL NIGERIA EXPLORATION AND PRODUCTIONSHELL NIGERIA EXPLORATION AND PRODUCTIONSHELL NIGERIA EXPLORATION AND PRODUCTIONSHELL NIGERIA EXPLORATION AND PRODUCTION

COMPANYCOMPANYCOMPANYCOMPANY LtdLtdLtdLtd

Bonga FPSOBonga FPSOBonga FPSOBonga FPSO

Plant Operating Procedures ManualPlant Operating Procedures ManualPlant Operating Procedures ManualPlant Operating Procedures Manual

Volume 4Volume 4Volume 4Volume 4

OIL STORAGE, HANDLING AND BALLAST SYSTEMSOIL STORAGE, HANDLING AND BALLAST SYSTEMSOIL STORAGE, HANDLING AND BALLAST SYSTEMSOIL STORAGE, HANDLING AND BALLAST SYSTEMS

OPRMOPRMOPRMOPRM----2003200320032003----0304030403040304

Version: 1.2

This document is not confidential.

The Copyright of this document is vested in Shell Nigeria

Exploration and Production Company Limited. All rights reserved.

Neither the whole nor any part of this document may be

reproduced, stored in any retrieval system or transmitted in any

form or by any means (electronic, mechanical, reprographic,

recording or otherwise) without the prior written consent of the

copyright owner.



SSShhheeelll lll NNNiiigggeeerrriiiaaa EEE &&& PPP CCCooommmpppaaannnyyy LLLtttddd... UUUnnnrrreeessstttrrriiicccttteeeddd

OPRM-2003-0304 Page ii of xii 30-April-2006

Document Status InformationDocument Status InformationDocument Status InformationDocument Status Information

1.0. DOCUMENT CONTRO1.0. DOCUMENT CONTRO1.0. DOCUMENT CONTRO1.0. DOCUMENT CONTROLLLL

1.1. Change History1.1. Change History1.1. Change History1.1. Change History

DateDateDateDate VersionVersionVersionVersion AuthorAuthorAuthorAuthorRefRefRefRef

IndicatorIndicatorIndicatorIndicatorChange DescriptChange DescriptChange DescriptChange Descriptionionionion

01/03/04 1.0 ODL – Issue of document for

signature.

31/08/05 1.1 ODL – Amendment to Part 1

Section 2 Paragraphs 2.2

and 2.3, and Section 5

Paragraphs 2.1 and 4.

Part 2 Section 1 Procedure

No 1/001 Valve Checklist

1 restructured; Valve

Checklist 2 and its

procedure updated; Valve

Checklist 3 restructured.


No 2/003 Danger notices

and Step 4 altered.


No 3/001 Step 10 altered;

Procedure No 3/002

Introduction altered;

Procedure No 3/004

Preamble and Step 22.

30/04/06 1.2 ODL/SNEPCO – Amended throughout to

address outstanding

HOLDs and to reflect the

latest PFS (Rev 00).

Amendments to Part 1

Section 5 Tables 5.2 and

5.3.




OPRM-2003-0304 Page iv of xii 30-April-2006

2.02.02.02.0 PURPOSEPURPOSEPURPOSEPURPOSE

The purpose of this document is to provide guidance on the safe, efficient

and environmentally aware operation of the Oil Storage, Handling and Ballast

Systems.

It is one Volume within an overall suite of Volumes, which comprise the

Bonga FPSO Plant Operating Procedures Manual (POPM). The full listing of

Volumes is as follows:

Volume 1 Field and Facilities Overview

Volume 2A Subsea Production System

Volume 2B Subsea Waterflood System

Volume 2C Subsea Control System

Volume 2D Flow Assurance Guidelines

Volume 3 Oil Separation and Treatment

Volume 4Volume 4Volume 4Volume 4 Oil Storage, Handling and Ballast SystemsOil Storage, Handling and Ballast SystemsOil Storage, Handling and Ballast SystemsOil Storage, Handling and Ballast Systems

Volume 5 Oil Metering and Export System

Volume 6 Vapour Recovery Compression System

Volume 7 Field Gas Compression System

Volume 8 Gas Dehydration/Glycol Regeneration Systems

Volume 9 Gas Export/Import/Lift Systems

Volume 10 Flare and Vent Systems

Volume 11 Produced Water Treatment Systems

Volume 12 Waterflood System

Volume 13 Chemical Injection and Methanol Injection System

Volume 14 Fuel Gas SystemVolume 15 Heating Medium System

Volume 16 Drainage Systems

Volume 17 Sewage Treatment Systems

Volume 18 Bilge and Oily Water Separation Systems

Volume 19 Inert Gas System

Volume 20 Nitrogen Generation System

Volume 21 Seawater System

Volume 22 Fresh and Potable Water Systems

Volume 23 Diesel Fuel System and Incinerator

Volume 24 Aviation Fuel SystemVolume 25 Instrument and Utility Air System

Volume 26 Deck Hydraulic Systems

Volume 27 Fire Protection Systems and Equipment

Volume 28 Safety and Lifesaving Equipment

Volume 29 PSCS and ESS

Volume 30 Power Generation and Distribution Systems

Volume 31 Black Start Procedures

Volume 32 HVAC Systems

Volume 33 Deck Machinery and Mechanical Handling Systems (Cranes, etc)

Volume 34 Telecommunications

Volume 35 Ancillary Living Quarters (ALQ)




OPRM-2003-0304 Page v of xii 30-April-2006

3.03.03.03.0 SCOPESCOPESCOPESCOPE

This document provides a detailed description of the plant and equipment,

which comprise the Oil Storage, Handling and Ballast Systems, and includes

step-by-step guidance on the operation of the system and its equipment,under both normal and abnormal operation.

4.04.04.04.0 TARGET READERSHIPTARGET READERSHIPTARGET READERSHIPTARGET READERSHIP

All SNEPCO staff, contractors and other third-party personnel who may be

involved in the operation of the Oil Storage, Handling and Ballast Systems

onboard the Bonga FPSO.

5.05.05.05.0 SPECIAL NOTESPECIAL NOTESPECIAL NOTESPECIAL NOTE

Not applicable.

6.06.06.06.0 ABBREVIATIONSABBREVIATIONSABBREVIATIONSABBREVIATIONS

The abbreviations used within this document are listed at the end of these

introductory pages.

7.07.07.07.0 REFERENCE INFORMATION/SUPPORTING DOCUMENTATIONREFERENCE INFORMATION/SUPPORTING DOCUMENTATIONREFERENCE INFORMATION/SUPPORTING DOCUMENTATIONREFERENCE INFORMATION/SUPPORTING DOCUMENTATION

The primary reference/supporting documents, which have been either used

or referred to in the development of this document, are listed at the end of

these introductory pages. These are part of the available OperationalDocumentation which SNEPCO Offshore Operations (OO) has in place to

support its day-to-day operations. These and many other documents are

available within the SNEPCO Livelink System. Where appropriate, these

documents have been cross-referenced within this document.




OPRM-2003-0304 Page vi of xii 30-April-2006

AbbreviationsAbbreviationsAbbreviationsAbbreviations

AC Alternating CurrentANSI American National Standards Institute

API American Petroleum Institute

APWBT Aft Peak Water Ballast Tank

BA Breathing Apparatus

bara Bar Absolute

barg Bar Gauge

BASEEFA British Approvals Service for Electrical Equipment in

Flammable Atmospheres

BBL Barrel

BOPD Barrel of Oil per Day

BPD Barrels per Day

BS&W Base Sediment and Water

BWPD Barrel of Water per Day

CCR Central Control Room

CI Chemical Injection

CIGM Clean Inert Gas Main

CIV Chemical Injection Valve

COT Crude Oil Tank

COW Crude Oil WashingCV Production Choke Valve

DC Direct Current

DCS Distributed Control System

DE Drive End

DIGM Dirty Inert Gas Main

ESD Emergency Shutdown

ESR 1 Process Shutdown

ESR 2 Surface Process Shutdown

ESR 3 Total FPSO Shutdown

ESS Emergency Support System

F&G Fire and Gas

FBHP Flowing Bottomhole Pressure

FC Fail Closed Valve

FCV Flow Control Valve

FG Flow Indicating Gauge

FIC Flow Indicating Controller

FLA First Line Ashore

FO Fail Open Valve




OPRM-2003-0304 Page vii of xii 30-April-2006

FPSO Floating Production, Storage and Offloading

FPWBT Forward Peak Water Ballast Tank

FT Flow Transmitter

FTP Flowing Tubing Pressure

GA General Alarm

GOR Gas/Oil Ratio

H High Alarm

HH High Trip

HCU Hydraulic Control Unit

HCV Hand Control Valve

HMI Human Machine Interface

HOV Hand-operated Valve

HP High Pressure

HPI High Performance Insulation

HPU Hydraulic Power Unit

HSE Health, Safety and Environment

HVAC Heating, Ventilation and Air Conditioning

Hz Hertz (Frequency)

ID Internal Diameter

IG Inert Gas

IGF Induced Gas Flotation

IMO International Maritime OrganisationIP Intermediate Pressure

IS Intrinsically Safe

ISO International Standards Organisation

kW Kilowatt

L Low Alarm

LAT Lowest Astronomical Tide

LC Locked Closed

LCV Level Control ValveLEL Lower Explosive Limit

LG Level Gauge

LIC Level Indicating Controller

LL Low Trip

LNG Liquefied Natural Gas

LO Locked Open

LOS Line of Sight

LP Low Pressure

LPG Liquified Petroleum Gas

LS Level Switch

LSA Low Specific Activity (Scale)




OPRM-2003-0304 Page viii of xii 30-April-2006

LT Level Transmitter

LU Level Unit

m3 Cubic Metres

MAC Manual Alarm Callpoint

MCC Motor Control Centre

MEG Mono Ethylene Glycol

MIV Methanol Injection Valve

MMSCFD Millions of Standard Cubic Feet per Day

MOV Motor Operated Valve

m/s Metre per Second

MSDS Material Safety Datasheets

MW Megawatt

NB Nominal BoreNC Normally Closed

NDE Non-drive End

NDT Non-destructive Testing

NGL Natural Gas Liquid

NO Normally Open

NPSHA Net Positive Suction Head Available

NRV Non-return Valve

OD Outside Diameter

ODMS Oil Discharge Monitoring System

OLI On-line Inspection

P&ID Piping and Instrument Diagram

PCV Pressure Control Valve

PDR Pressure Difference Ratio

PDS Differential Pressure Switch

PDT Differential Pressure Transmitter

PFD Process Flow Diagram

PG Pressure Gauge

PIC Pressure Indicator Controller

PIL Process InterlocksPIV Pigging Isolation Valve

PM Production Manifold

PMV Production Master Valve

ppm v/v Part per Million by Volume

ppm wt/wt Parts per Million by Weight

PT Pressure Transmitter

PTW Permit to Work

RTJ Ring Type Joint

RV Relief ValveRVP Reid Vapour Pressure




OPRM-2003-0304 Page ix of xii 30-April-2006

Abbreviations (cont’ d)Abbreviations (cont’ d)Abbreviations (cont’ d)Abbreviations (cont’ d)

SCSSV Surface Controlled Subsea Safety ValveSCU Subsea Control Unit

SDV Shutdown Valve

SI Statutory Instrument

SIL Shutdown Interlocks

Sm3/hr Standard Cubic Metres per Hour

SSDS Safety Shutdown System

STIL Startup Interlocks

SWL Safe Working Load

SWP Safe Working Pressure

SWV Sacrificial Wing Valve

TC Tank Cleaning

TCV Temperature Control Valve

TEG Tri-ethylene Glycol

TG Temperature Gauge

TIC Temperature Indicating Controller

T/T Tangent to Tangent (Vessel Length)

TT Temperature Transmitter

TVP True Vapour Pressure

UEL Upper Explosive LimitUPS Uninterruptible Power Supply

UV Ultraviolet

VDU Visual Display Unit

VRU Vapour Recovery Unit

WBT Water Ballast Tank

WI Water Injection

WSV Well Switching Valve

XOV Crossover Valve




OPRM-2003-0304 Page x of xii 30-April-2006

Reference Information/Supporting DocumentationReference Information/Supporting DocumentationReference Information/Supporting DocumentationReference Information/Supporting Documentation

Project DataProject DataProject DataProject Data

Document No/RDocument No/RDocument No/RDocument No/Refefefef Document TitleDocument TitleDocument TitleDocument Title

BON-AME-3GN-J-15658-005 Rev

A03

Ballast Tanks – PFS


A01

Cargo Storage and Handling – PFS (NAPA)


A01

PFS Cargo Storage and Handling

BON-SHI-P-00002-001/002/003-00

Ballast System (Sheets 1, 2 and 3)

BON-SHI-P-00002-004/005-00 Air Sounding System (Sheets 1 and 2)

BON-SHI-P-00002-007-00 Position of Tank Gauging

BON-SHI-P-00002-008-00 Crude Oil Headers

BON-SHI-P-00002-009 to 016-00 Storage Compartments (1 to 8)

BON-SHI-P-00002-017-00 Storage Compartments 8 (Tank Utilities)

BON-SHI-P-00002-08-00 Tank Cleaning and Nitrogen Headers

BON-SHI-P-00002-019 to 024-00 Storage Compartments 1 to 7 (Utilities)

Vendor DataVendor DataVendor DataVendor Data

VendorVendorVendorVendor Document NumberDocument NumberDocument NumberDocument Number Document TitleDocument TitleDocument TitleDocument Title

FRAMO FRAMO doc 1008 dated

2/7/2002/TS

Service Manual for Cargo

Pumping System

SAAB BON/1DA2617/SAAB/000001 Load Computer

FRANK

MOHN

BON/1JA0980/FRANK/000003 Ballast Pump

NIASCO BON/1YA1151/NIASCO/000001 Valve Remote Control System

Ballast Valves

SAAB BON/1DA2177/SAAB/000002 COT Level Gauging System

CONSILIUM BON/1DA2160/CONSILIUM/0000

01

Remote Sounding System

(Ballast, FO)





OPRM-2003-0304 Page xi of xii 30-April-2006

GUNCLEAN BON/1FA1108/GUNCLEAN/0000

01

Fixed Tank Cleaning Machine

FRANK

MOHN

BON/1JA0980/FRANK/000001 Cargo Oil Pump

SEIL BON/1SA1043/SEIL/000001 Oil Disch Monitoring System


CONSILIUM BON/1DA2160/CONSILIUM/0000

01

Remote Sounding System

(Ballast, FO)

HEMP ActionsHEMP ActionsHEMP ActionsHEMP Actions

NoNoNoNo DescriptionDescriptionDescriptionDescription Control MeasureControl MeasureControl MeasureControl Measure ODL ActODL ActODL ActODL Actionionionion

1 Portable Cargo Pump (Part 2

Section 2 Procedure No

2/004).

Steps for hooking up the

hoses need to give

details about the

minimum requirements

such as pressure

ratings, connection

types, material of

construction etc.

Caution added to

Part 2 Section 2

Procedure No

2/004.




OPRM-2003-0304 Page xii of xii 30-April-2006

Main Table of ContentsMain Table of ContentsMain Table of ContentsMain Table of Contents

Document Status InformationDocument Status InformationDocument Status InformationDocument Status Information

AbbreviationsAbbreviationsAbbreviationsAbbreviations

Reference Information/Supporting DocumentationReference Information/Supporting DocumentationReference Information/Supporting DocumentationReference Information/Supporting Documentation

Part 1Part 1Part 1Part 1 –––– Technical DescriptionTechnical DescriptionTechnical DescriptionTechnical Description

Section 1Section 1Section 1Section 1 System OverviewSystem OverviewSystem OverviewSystem Overview

Section 2Section 2Section 2Section 2 Detailed DescriptionDetailed DescriptionDetailed DescriptionDetailed Description –––– Cargo LoadingCargo LoadingCargo LoadingCargo Loading

SecSecSecSection 3tion 3tion 3tion 3 Detailed DescriptionDetailed DescriptionDetailed DescriptionDetailed Description –––– Ballast SystemBallast SystemBallast SystemBallast System

Section 4Section 4Section 4Section 4 Detailed DescriptionDetailed DescriptionDetailed DescriptionDetailed Description –––– Crude Oil WashingCrude Oil WashingCrude Oil WashingCrude Oil Washing

Section 5Section 5Section 5Section 5 Detailed DescriptionDetailed DescriptionDetailed DescriptionDetailed Description –––– Slops SystemSlops SystemSlops SystemSlops System

Part 2Part 2Part 2Part 2 –––– Operating ProceduresOperating ProceduresOperating ProceduresOperating Procedures

Section 1Section 1Section 1Section 1 System Operating ProceduresSystem Operating ProceduresSystem Operating ProceduresSystem Operating Procedures

Section 2Section 2Section 2Section 2 Equipment Operating ProceduresEquipment Operating ProceduresEquipment Operating ProceduresEquipment Operating Procedures

SectiSectiSectiSection 3on 3on 3on 3 Supplementary Operating ProceduresSupplementary Operating ProceduresSupplementary Operating ProceduresSupplementary Operating Procedures



Shell Nigeria E & P Company Ltd. Unrestricted

PART 1

TECHNICAL DESCRIPTION

Section 1 System Overview

Section 2 Detailed Description – Cargo Loading

Section 3 Detailed Description – Ballast System

Section 4 Detailed Description – Crude Oil Washing

Section 5 Detailed Description – Slops System

Part 1 Technical Description

OPRM-2003-0304 Page 1 of 1 30-April-2006




Part 1Technical Description

Section 1System Overview

Table of Contents

1.0 INTRODUCTION.............................................................................................................2

2.0 PROCESS DESCRIPTION.............................................................................................2

2.1 Crude Oil Loading and Storage........................................................................... 2

2.2 Ballast System.....................................................................................................4

2.3 Tank Cleaning Systems.......................................................................................4

2.4 Slop Tank System ............................................................................................... 7

2.5 Crude Oil Offtake.................................................................................................8

3.0 HEALTH, SAFETY AND ENVIRONMENT (HSE) ..........................................................8

3.1 General................................................................................................................8

3.2 Specific Hazards..................................................................................................9

3.3

Environmental Issues ..........................................................................................9

FIGURES

Figure 1.1 – Oil Storage and Offloading Facilities Overview..................................................10

Figure 1.2 – Ballast Facilities Overview ................................................................................. 11

Part 1 Section 1 System Overview





1.0 INTRODUCTION

Bonga FPSO is a spread moored barge shaped vessel at the Bonga field offshoreNigeria. It is moored with a 12-anchor spread in 1000m water depth and producesfrom a network of remote subsea wells connected to Bonga FPSO by a system ofseabed pipelines and risers. Well fluids are treated in the topside processingfacilities and dry crude oil is stored in the hull cargo tanks. Associated gas isexported by pipeline to the Liquefied Natural Gas (LNG) terminal at Bonny and anyproduced water is treated before being disposed of overboard. Treated seawater ispumped into the reservoir to maintain reservoir pressure and thus enhanceoil recovery.

The Cargo and Ballast System can be broken down into the following fivesub-sections:

• Crude Oil Loading and Storage

• Ballast System

• Crude Oil Washing

• Crude Oil Slops System

• Crude Oil Offtake

These systems are primarily concerned with the safe storage of crude onboardBonga FPSO, and counter-action of the effects of the crude on the vessel stabilityand structural integrity.

2.0 PROCESS DESCRIPTION

Refer to Figure 1.1.

2.1 Crude Oil Loading and Storage

The crude oil, recovered from the well fluids, is stabilised before passing through thecrude coolers to storage. The coolers reduce the temperature of the crude product

to below 43.3°C. Isolation valves are fitted to the crude outlet line from the coolersupstream of the tie-in point of the produced oil line to provide topside isolationfrom storage.

Stabilised crude oil at a maximum flowrate of 1450m3/hr from the oil processingfacilities can be loaded through a loading header and drop lines, fitted withhydraulically operated isolation valves, into selected Cargo Tanks as required

in accordance with the pre-calculated loading plan. Each tank spur feeds theport centre and/or starboard cargo tank through a manual isolation and ahydraulically operated valve.

Loading into the cargo tanks is carried out on a continuous basis from the topsidesprocessing module through the loading header and into the selected cargo tanks,normally the reception tank COT 3C. In the reception tank, some separation will takeplace to further reduce the water content.

From COT 3C the oil overflows a standpipe and the crude oil is cascaded by gravityto COT 2C and COT 4C from where it can be transferred via bottom transfer valvesinto adjacent tanks, or pumped to any other tank via the crude oil transfer header inaccordance with the loading plan. As an alternative, COT 5C can be used as

reception tank if COT 3C is out of service.






Crude capacity of the 15 Crude Oil Tanks is 2,039,200 barrels (324,233m 3),however it is unlikely that all tanks will be completely filled as the crude is offloadedprior to reaching this point. If there is any delay in offloading due to problems withthe tanker or offloading facilities it may be necessary to reduce and, in extreme

cases, stop oil production.

A submerged, hydraulically driven, Cargo Oil Pump is provided in each COT todeliver crude from the associated tank to the discharge header for export (refer toVolume 5 Oil Metering and Export System (OPRM-2003-0305)) or to the transferheader when being decanted to another COT.

The Framo hydraulic system is designed for simultaneous operation of fivesubmerged cargo pumps and two water ballast pumps.

The cargo piping system is configured to permit loading of crude oil into the cargotanks and simultaneously offloading to the export tanker, using a combination ofmanual and remote hydraulically operated valves.

Each cargo tank and the two slop tanks are provided with a Saab radar tank levelgauge, a Metritape backup level gauge, pressure sensors and temperature sensorsthat provide information to the DCS System and the Load Computer.In addition to these sensors, oil-water interface level sensors are provided in theslop tanks and the reception tank COT 3C.

Manual sounding points are also provided for each tank. These allow the operator tomonitor the filling or emptying of each tank through tank dips as planned in amanually controlled loading or offloading programme in order to meet the designoperational and safety requirements of Bonga FPSO.

Export of crude oil to the offtake tanker is normally via the offloading cargo systemand the topsides SPM booster pumps to the calm buoy, or via the stern offloading

facility if the calm buoy is unavailable.

Stripping facilities are provided on the cargo pumps to permit the operation of thecargo pumps when pumping from a tank when the level is very low, such as duringthe removal of any residual fluids from the tank prior to tank cleaning.

During the stripping process the submerged pump is operated under local controlfrom the Framo control panel. Compressed nitrogen is injected at the base of thepump discharge column to lift the oil up through the column. Stripping ensures thatthe tank can be totally emptied prior to, and during, cleaning operations. It is notenvisaged that the tanks will be stripped on the completion of every discharge,as Bonga FPSO storage capacity is much greater than the anticipated offloadedparcel size.

Oily water mixtures from the topsides equipment are normally routed to the port(dirty) slop tank but can, if required, be routed to the primary reception tank, COT3C. Generally the liquid to these tanks is from drains or overflows in the processsystems. When the produced water quality is such that it cannot be disposed ofdirectly overboard, it is directed to one of these tanks.






Gravity separation of the liquid phases in the port slop tank occurs allowing the oiland emulsion to be drawn off and returned to storage using the skimming pump.Clean water is then passed to the starboard slop tank, where it is polished prior todisposal overboard. The oil content of water to overboard disposal from the

starboard slop tank is continually monitored to ensure it is below the maximumoil-in-water content.

Note: No transfer of crude oil, ballast or other significant weight transfer should be performed without first simulating the weight transfer on the loadingcomputer, in compliance with the Cargo Planning Procedure.

2.2 Ballast System

Refer to Figure 1.2.

A segregated Ballast System, in compliance with MARPOL 73/78, is used to adjustdraft, trim and list of the hull to control transverse stability and structural loading.

Ballast water is stored in 12 Water Ballast Tanks (WBTs), six down each side of thevessel outside of the crude oil tanks. A ballast main runs through each set of sixwing tanks, allowing the distribution of ballast to and from each tank.

Two further ballast tanks, the fore peak tank and the aft peak tank, can also be usedto take ballast if required. The arrangement of the ballast wing tanks and crude oiltanks provides protection to the crude tanks in the event of a rupture of theship’s hull.

A certain amount of ballasting and de-ballasting can be carried out under gravityusing the draught differential to fill or empty the tanks, although normally adjustmentof ballast is carried out using the two ballast pumps located in BWT 4 Port and BWT4 Starboard.

Level monitoring in the ballast tanks uses a Metritape System as primary andRF Admittance Probe type for backup and independent high-level indication,which provides level indication to the DCS and the Load Computer.

The Ballast System can also be used to supply seawater to the Tank CleaningSystem when water washing is to be carried out.

An emergency inert gas connection to the Ballast System allows the ballast mainsand tanks to be purged and inerted with inert gas should hydrocarbons leak into thetanks.

Seawater for ballasting is taken onboard via the port and starboard sea chests.The sea chests are manually treated with sodium hypochlorite for the control ofmarine growth.

Ballasting and de-ballasting operations are carried out from the DCS.

2.3 Tank Cleaning Systems

Crude oil washing is carried out to ensure the vessel is operated in accordance withthe requirements of Regulation 13B of the Protocol of 1978 to the InternationalConvention for the Prevention of Pollution from Ships 1973 (MARPOL 73/78).

Crude Oil Washing Systems should be operated in accordance with the IMCORevised Specifications for the Design, Operation and Control of Crude Oil WashingSystems (A.446 (XI)).






Bonga FPSO is equipped with fixed tank cleaning machines served by fixed pipingthat can be used with either crude oil or seawater as a washing medium.

Although it is possible to crude oil wash several tanks simultaneously, the normalpractice is to clean one cargo oil tank at a time. Normal tanker practice is to crude oilwash during discharge; on Bonga FPSO, crude oil washing will be performedbetween offtakes, thus avoiding reducing the pumping rate to the export tanker.The deck-mounted programmable washing machines can be selected to do a fullclean or a bottom clean. If bottom clean is selected, the nozzle of the machine is

elevated to no higher than 30° so that only the lower section of the walls and base ofthe tank are cleaned. A crude oil tank containing dry crude is used to supply thewashing media to clean an empty tank.

The standard washing cycle is one full cycle followed by one bottom cycle on theprogrammable machines, while at the same time running the bottom-mountedmachines. The time required for a full-cycle wash is approximately 60 minutes andthe time duration of a tank bottom wash is approximately 30 minutes.

The residues and any sediment from the cargo oil tank being washed is pumped outusing the submerged cargo pump of that tank discharging into the transfer header.From the transfer header it can be routed back to any cargo tank but normally to thetank which is supplying the wash fluid. It must never be routed to the slop tanks.The contents of the supply tank are then exported at the next offtake.

The manual isolation valves fitted on the individual feed lines to the cleaningmachines should not be throttled to control the pressure of the crude oil supply tothe machines.

Tank cleaning is normally followed by water washing if entry to the cargo tank isrequired.

Crude oil washing has the major benefit that cargo residues, which mainly consist ofsettled-out waxy and asphaltic substances, are dissolved and subsequentlydischarged with the rest of the cargo. This substantially reduces the amount ofresidues left in the cargo tanks. Crude oil washing can only be practised on vesselsfitted with an Inert Gas System.

Tank cleaning, by cold or hot seawater washing, is normally only carried out on atank when access is required for inspection or repair. The tank will normally becleaned using the same fixed tank cleaning machines that are used for crude oilwashing. Movement of water at high velocity can generate static electricity, thereforewater washing is always performed in an inert atmosphere.

IT IS ESSENTIAL THAT THE OXYGEN LEVEL IN THE VAPOUR SPACE OFTHE TANK IS MAINTAINED BELOW 5% (VOLUME) AT ALL TIMES

DURING TANK WASHING. FOR THIS REASONTHE INERT GAS SYSTEM MUST BE AVAILABLE PRIOR TO THE

COMMENCEMENT OF TANK WASHING.






During seawater washing operations, a closed or open cycle method may be used.In either case, tank washings are returned to the dirty slop tank for separation priorto disposing overboard via the Slop Tank System.

Seawater for tank washing is supplied to the tank cleaning header either from theclean slop tank or from the tank cleaning pump which is supplied from one of thestarboard ballast pumps.

2.3.1 Closed Cycle Wash

If the slop tanks are to be used, before seawater washing operations commence,the port and starboard slop tanks are charged with seawater to an ullage ofapproximately 15m, sufficient to cover the outlet from the decant line in the cleanslop tank.

The Slop Pump P-2605A submerged in the starboard slop tank is then started andutilised to pump clean seawater from the slop tank to the COW/TC header and

thence to the tank cleaning machines on the tank to be washed. At the same time, the submerged cargo pump located in the cargo oil tank beingwashed, strips the tank and returns the oily water from the tank to the port slop tankfor separation. Following separation in the port slop tank, the recovered crude oilcan be directed to a cargo tank using the skimmer pump.

The cleaned wash water from the port slop tank is decanted to the starboardslop tank then pumped overboard, monitored by the Oil Discharge MonitoringSystem (ODMS).

2.3.2 Open Cycle Wash

Open cycle washing is normally only used where there is insufficient clean seawater

in the slop tanks, the starboard slop pump is not available or when washing theslop tanks.

During an open cycle wash, clean seawater is supplied by one of the starboardBallast Pumps P-5804C/D from the starboard sea chest to the Tank Cleaning PumpP-2604 (refer to Part 1 Section 3).

There is a Filter P-2604-S-01 fitted with a differential pressure alarm on the suctionside of the tank cleaning pump. A removable spool is fitted on the discharge side ofthe pump that must be fitted before the line is used.

As this is a hydrocarbon/non-hydrocarbon system interface it is importantthat this spool is removed when not in use to avoid the possibility of

contaminating the ballast system.The tank cleaning pump discharges into the COW/TC header. The procedure forstripping the tank being washed back to the port slop tank and subsequenttreatment of the washings is the same as for a closed cycle wash.

The slop tanks can only be water washed using the open cycle method. The cleanslop tank can be washed and the washings pumped to the port slop tank via thetransfer main. The port (dirty) slop tank can be similarly washed to the starboard(clean) slop tank, however, in order to avoid contaminating the starboard slop tank itis preferable to direct the port slop tank washings via the transfer main to the cargoreception tank, 3C.






The minimum operating parameters for any system during seawater washing areas follows:

• Seawater pressure at cleaning machine – 8barg

• Flowrate deck-mounted machines – 87m3/hour

• Flowrate bottom-mounted machines – 39m3/hour

A suitable number of closed ullage stations are provided for each cargo oil tank andslops tank to check the tank before and after cleaning. Two stands fitted with avapour seal valve for use with appropriate 2in portable measuring instrument areprovided for each cargo oil tank and slop tank. Two stands fitted with a vapour sealvalve for use with appropriate 1in portable measuring instrument are provided foreach cargo oil tank and one in each slop tank.

Tank washings are returned to the dirty slop tank for disposal whether open orclosed cycle washing is employed.

2.4 Slop Tank System

The slop tanks are designed to treat mixtures of water and entrained oil from crudeoil processing, cargo handling, cargo tank washings, open and closed drains andbilge systems. The port (dirty) Slop Tank T-2603 receives the mixtures to allowtime for settling out before transfer of the water to the starboard (clean) SlopTank T-2602.

Oil is removed from the upper part of the dirty slops tank by a Dirty Slops Tank OilSkim Pump P-2603 which delivers the wet oil to a selected cargo tank, normally thereception tank 3C. Water is decanted to the starboard slop tank to allow furtherseparation of oil before being pumped overboard.

The hydraulically driven skimming pump has a capacity of 100m3/hour. The suctionof the pump is set approximately 10m from the top of the tank.

Both slop tanks have a hydraulically driven slop pump installed in a similar mannerto the cargo pumps. The pumps each have a capacity of 400m 3/hour and candischarge to either the transfer header or tank-cleaning header.

After confirmation by sampling that the oil-in-water content of the starboard cleanslop tank is below 29ppm, water can be discharged overboard by the clean wateroverboard pump. The overboard discharge is monitored for quality by the ODMSand, if oil content is above specification, the flow is directed to the dirty slop tank.

If a significant amount of oil collects on the surface of the clean starboard slop tank it

can be skimmed from the surface by filling the tank with water. When the oil/waterinterface level is above the upper oil skim pipe inlet (70% tank height) the top levelcan be run off back into the port tank by hydrostatic head via the Remote-operatedValves 26-ZCV-108 and 26-ZCV-109.

There are also facilities to isolate the flow to the transfer header and pump to theFlare Scrubber V-4640 for disposal to the LP Separator V-2340A via the FlareScrubber Pumps P-4640A/B/C.






2.5 Crude Oil Offtake

The Offtake System is designed to offload the crude cargo from the vessel to anexport tanker safely and efficiently, whilst also maintaining loading into the storagetanks from the production facilities. The export of crude oil from Bonga FPSO to theofftake tanker can be either via the SPM buoy or via the stern discharge system.

A cargo pump is located in each of the cargo tanks and can be lined up to thedischarge header or to the transfer header. The cargo pumps are powered byvariable speed hydraulic motors and have their suction 100mm above the base ofthe tank. Each pump can deliver crude to the discharge header at 1500m3/hour.The design export rate is 7500m3/hour, requiring up to five cargo tanks to bepumped out simultaneously.

Nitrogen is injected at the base of the pump discharge column, this then lifts the oilin the column on a pocket of gas during stripping. Stripping ensures that the tankcan be totally emptied prior to and during cleaning operations.

It is not envisaged that the tanks will be stripped on the completion of everydischarge, as Bonga FPSO storage capacity is larger than the anticipated offloadedparcel size.

From the discharge header, the oil flows through the LACT metering package(fiscal meter) topsides before being directed to the topsides CALM booster pumps orto the stern discharge system.

Note: For details and operation of the Cargo Offloading and LACT MeteringSystems reference should be made to Volume 5 Oil Metering andExport System.

3.0 HEALTH, SAFETY AND ENVIRONMENT (HSE)

3.1 General

The Cargo and Ballast System is located mostly in the vessel hull with somepipework on the vessel topsides, which is part of the main topside operating area.

All personnel in the areas must have received training in, and be fully conversantwith, the following:

• Location and use of fire and safety equipment in the area

• Recognition and response to all the vessel’s visual and audible alarms

•Muster and evacuation procedures

• Escape routes

• Location and use of lifesaving equipment






3.2 Specific Hazards

The Cargo and Ballast System handles crude oil and separated water at relativelylow temperature (below 43°C) and pressure. Hazards are therefore low comparedwith other processing systems. The oil storage tanks are inert gas blanketed.

However, it is incorrect to assume that no hazards exist. Potential hazards includethe following:

• If storage tank levels containing water/crude oil mix are left static for a period oftime there is a real danger of large quantities of H2S being generated when thetanks are disturbed

• Most of the pumps and actuated valves used in operation of the system aredriven from a high-pressure hydraulic system

• The cargo tanks are inerted using inert gas supplied from the inert gas system.The inert gas is an asphyxiant and may contain toxic gases such as carbon

dioxide and carbon monoxide

• The Cargo and Ballast System employs various items of rotating equipmentwhich must have all moving parts securely guarded at all times

• Excessive list, trim and hull stress causing structural integrity concerns

• Oil pollution/spills to ballast tanks or to outside directly

All personnel must wear the appropriate protective clothing (overalls, safety helmet,gloves, goggles etc) when in the area, and wear hearing protection if noise levels inthe area are high.

3.3 Environmental Issues

3.3.1 Overboard Discharge

Since the Cargo, Slops and Ballast System discharges effluent overboard,environmental issues could arise if the discharge fails to meet the target requirementof less than 29ppm monthly average, with a maximum single occurrence of 40ppm.The water effluent is continuously monitored for oil at the discharge point and if itsquality deteriorates below the acceptable value, the off-specification water isautomatically diverted to the dirty slops tank for further treatment.





Shell Nigeria E & P Company Ltd.

DERIVED FROM PFD BON-AME-3GN-B-21192-006-C02

FC

FC

FI

TO FLARE

SCRUBBER

FROM CRUDE

COOLER

TO PRODUCTION FLARE

HEADER

FORWARD

HEADER

DRAIN

TRANFER HEADER

CRUDE OIL LOADING HEADER

FROM OIL

DEGASSING TANK

FROM PRODUCTION

SUMP AND

COLLECTION TANKS

TO SUBSEA

FLOWLINE WARMUP

PIGGING EXCHANGE

REMOVABLE

SPOOL

ESD

ESD

ESD

ESD

TO SUBSEA

FLOWLINE WARMUP

PIGGING EXCHANGE

CRUDE OIL WASH AND TANK CLEANING HEADER

BACKFLUSH/METER PRO

FROM FLARE

SCRUBBER

FROM INDUCED GAS

FLOTATION SEPARATOR

P-2604

TANK CLEANING

BOOSTER PUMP

FROM

BALLAST SYSTEM

(FOR TANK CLEANING)

INERT GAS

FROM

OIL

DEGASSING

TANK

AFT

CARGO HOSE

CLEANING MANIFOLD

AFT

HEADER DRAIN

T-2603

DIRTY SLOP TANK

T-2603

CLEAN SLOP TANK T ANK T-2601 M(5S) TANK T- 2601 J(4S) TANK T- 2601 G(3S)

SEAL LOOPS

SEAL LOOPS

TANK T-2601 E(2S) TANK T-2601 A(1S)

P-2605A

SLOP TANK

PUMP

TANK T-2601 O(5P)

P-2061O

CARGO

PUMP

P-2061N

CARGO

PUMP

P-2061L

CARGO

PUMP

P-2061I

CARGO

PUMP

P-2061F

CARGO

PUMP

P-2061C

CARGO

PUMP

P

P-2

P-2

TANK T-2601 L(4P) TANK T-2601 F(2P) TANK T-2601 C(1P)

SEE NOTE 1

NO

FROM

I/G

FLOTATION

SEPARATOR

FROM

PRODUCED

WATER

TANK

DIS

TR

OVERBOARD

VIA ODME

A-2742

LACT SAMPLE

CABINET

P-0821A

CIRCULATION

PUMP

P-0821B

CIRCULATION

PUMP

DISCHARGE HEADER

P-2605B

SLOP TANK PUMP

P-2603

SLOP OIL

SKIMMING

PUMP

P-2602

CLEAN WATER

DISCHARGE PUMP

T-2601 N(5C)

BACK-UP

RECEPTION

TANK

T-2601 H(3C)

BACK-UP

RECEPTION

TANK

T-2601 K(4C)

TANK

T-2601 D(2C)

TANK

T-2601 B(1C)

TANK

TANK T-2601 I(3P)

P-2061M

CARGO

PUMP

P-2061J

CARGO

PUMP

P-2061G

CARGO

PUMPP-2061E

CARGO

PUMP

P-2061A

CARGO

PUMP

P-2061B

CARGO

PUMP

P-2061D

CARGO

PUMP

P-2061K

CARGO

PUMP

P-2061H

CARGO

PUMP


OPRM-2003-0304 Page 10 of 11





OPRM-2003-0304 Page 11 of 11

A.P.T

T-6501(P)

No 6 WBT (P&S)

T-5801(P)

T-5801(S)

No 5 WBT (P&S)

T-5801(P)

T-5801(S)

No 4 WBT (P&S)

T-5801(P)

T-5801(S)

No 3 WBT (P&S)

T-5801F(P)

T-5801G(S)

No 2 WBT (P&S)

T-5801D(P)

T-5801E(S)

SLOP

OIL

TANK

(P)

P-5804A/B

SUBMERGED BALLAST PUMPS

P-5804C/DSUBMERGED BALLAST PUMPS

LOAD WATER

LINE

FROM

SEA CHEST CHLORINE

DOSING

SLOP

OIL

TANK

(S)

FROM

SEA CHEST

FROM CLEAN

INERT GAS SYSTEM

FROM CLEAN

INERT GAS SYSTEM

TO CARGO

TRANSFER HEADER

CHLORINE

DOSING

LOAD WATER

LINE

DERIVED FROM P&IDs BON-SHI-008-P-000002-001/002-00





Section 2Detailed Description – Cargo Loading

Table of Contents

1.0 INTRODUCTION.............................................................................................................3

2.0 EQUIPMENT DETAILS .................................................................................................. 3

2.1 Loading Facilities.................................................................................................3

2.2 Cargo Oil Storage Tank T-2601C (Typical).........................................................4

2.3 Cargo Reception Tank T-2601H (COT 3C).........................................................6

2.4 Cargo Transfer Header........................................................................................7

3.0 CONTROL AND INSTRUMENTATION..........................................................................8

3.1 Control Overview.................................................................................................8

3.2 Tank Level Gauging ............................................................................................ 9

3.3 NAPA Loading Computer .................................................................................. 12

3.4

Cargo Loading Control ......................................................................................15

3.5 Cargo Transfer .................................................................................................. 15

3.6 Operator Interface for Loading Operations........................................................17

3.7 Cargo Pump Interlocks......................................................................................18

4.0 SAFEGUARDING.........................................................................................................19

TABLES

Table 2.1 – Crude Oil Tank Capacities .................................................................................... 6

Table 2.2 – Cargo Tank Alarm and Trip Settings................................................................... 10

Table 2.3 – Associated Tag Numbers for COT ...................................................................... 16

Table 2.4 – Startup Interlocks (STIL) – Cargo Pumps P-2601A to O.....................................18

Table 2.5 – Process Interlocks for Cargo Pumps P-2601A to O............................................ 18

Part 1 Section 2 Detailed Description – Cargo Loading





Table of Contents (cont’d)

FIGURES

Figure 2.1 – Graphical Interface – Cargo Headers ................................................................ 20

Figure 2.2 – Graphical Interface – Cargo Storage ................................................................. 21

Figure 2.3 – Hull Tanks – Level System Schematic...............................................................22






1.0 INTRODUCTION

The purpose of the Cargo Loading System is to allow, in conjunction with the ballastsystem, crude oil cargo to be distributed to the cargo oil tanks to maintain thevessel’s stability within the specified design envelope to avoid causing excessivestresses or bending moments in the hull. The cargo storage tanks are used to storethe treated and stabilised crude oil production for regular offloading, approximatelyevery 5 days, to the tankers via the single point buoy mooring system or the SternDischarge System (when the single point mooring buoy is not available).

The cargo loading facilities consists of the following pieces of equipment:

• Loading Header

• Cargo Storage Tanks

• Transfer Headers

Loading into the cargo tanks is carried out on a continuous basis from the topsides

processing module through the loading (rundown) header and into the selectedcargo tanks.

Refer to the following P&IDs:

• BON-AME-3SP-B-21425-001 Crude Cooler

• BON-SHI-008-P-00002-008 Crude Oil Headers

• BON-SHI-008-P-00002-011 Storage Compartment 3





• BON-SHI-008-P-00001-012 Position of Tank Gauging and HandDipping System

2.0 EQUIPMENT DETAILS

2.1 Loading Facilities

Refer to Figure 1.1 or P&IDs BON-SHI-008-P-00002-011 Storage Compartment 3,BON-SHI-008-P-00002-008 Crude Oil Headers and BON-AME-3SP-B-21425-001Crude Cooler.

Equipment Description

Processed oil from the crude oil coolers flows down the rundown line through theIsolation Valve 25-MOV-401 into the 20in (500mm) loading header. The loadingheader runs the length of the main deck to allow oil to be distributed to the 15 cargotanks as required.






There are five sets of cargo tanks numbered one to five from the forward end ofthe vessel. Above each set of tanks there is a 20in (500mm) (Nos 1 and 2 Tanksare 14in (350mm)) transverse manifold running, connected to the loading headerthrough a remotely operated, hydraulically actuated butterfly valve. The manifold

delivers oil to each of the three tanks in each set, Port, Centre and Starboard,through a drop line that extends almost to the bottom of each tank. The drop line isisolated from the manifold by a manual butterfly valve and a remotely operated,hydraulically actuated butterfly valve.

Each drop line has a removable spool to provide positive isolation of the tank fromprocessed crude.

Each of the five manifolds also have a connection to the transfer header, describedin the following paragraphs, complete with a remotely operated, hydraulicallyactuated butterfly valve.

2.2 Cargo Oil Storage Tank T-2601C (Typical)

Equipment Details

Tag Number: T-2601C

Capacity: 18,740m3

Maximum OperatingPressure: 1400mm WG (1.4barg)

Minimum OperatingPressure: 400mm WG (0.4barg)

Refer to Figure 1.1 and P&IDs BON-SHI-008-P-00002-015 Storage Compartment 7,and BON-SHI-008-P-00002-024 Storage Compartment 7 Tank Cleaning

and Utilities.


The following paragraphs describe Crude Oil Tank T-2601C (COT 1P). The othercrude oil storage tanks have similar facilities.

Crude enters the tank via a 14in (350mm) nominal bore drop line from the loadingheader/manifold. The tank drop line incorporates Valve 26-ZCV-011 on the maindeck. The valve is hydraulically actuated controlled from the DCS. Open and closedposition signals are provided to the DCS by position switches.

In normal operation the tank is connected to the dirty inert gas header throughThree-way Valve 55-SV-001 to maintain a positive pressure in the tank under allconditions. Pressure in the dirty inert gas header is controlled by Pressure ControlValve 55-PCV-104, set at 800mm WG (0.8barg), that relieves pressure to the ventriser. During offloading operations, pressure in the dirty inert gas header ismaintained by operation of the inert gas generators.

Alternatively, during inerting and gas freeing operations Three-way Valve 55-SV-001is used to connect the tank to the clean inert gas header. Venting in this operation isprovided through a 10in (250mm) line which extends down to the bottom of the tankand connects to the crude oil purge main. Isolation of this line is provided by amanual Butterfly Valve 55-BUV-003. Refer to POPM Volume 19 Inert Gas System(OPRM-2003-0319).






The tank is protected against over-pressurisation or vacuum conditions throughPressure/Vacuum Valve 55-RV-003 located on the 10in (250mm) connection to thevent main. This valve has two settings, 1600mm WG (1.6barg) to relieve overpressure conditions and -200mm WG (-0.2barg) to relieve vacuum conditions.

Pressure relief is to the crude vent header.

For tank isolation, a spectacle blind is provided in the connection to the clean anddirty inert gas headers and the crude oil purge main. A removable spool is providedbelow the Relief Valve 55-RV-003 and on the oil loading line.

Communication with tanks in the next set is provided through the lower transfervalves, for example COT 1P can be connected to COT 2P by opening 26-ZCV-071located in COT 1P and 26-ZCV-070 in COT Number 2P.

The valves can be used to transfer oil in either direction between tanks whenfilling tanks or to allow both tanks to be offloaded using one pump if the other is outof service.

The valves are operated from the DCS and position of the valves is indicated on theDCS by measuring the flow of hydraulic oil to the valve actuator.

In the cargo oil tank Sets 2 and 4, lower transfer valves are provided for transfer foreand aft, and between adjacent tanks in the set.

Offloading from the tank is carried out using the dedicated Cargo Pump P-2601Cwhich takes suction from the bottom and towards the aft end of the tank. The pumpis a hydraulically driven submersible Framo pump controlled from the DCS.In exceptional circumstances it can be controlled locally from the Framo panel.The pump discharges into the common manifold for the No 1 cargo tanks and oninto either the discharge or transfer headers. Each pump has a discharge capacityof 1500m3/hr, at 150nlc. Refer to POPM Volume 5 Oil Metering and Export System

(OPRM-2003-0305).

As a backup there is one portable cargo pump which can be inserted into the tankthrough a Butterworth hatch in the tank top. A tie-in to the hydraulic supplyis provided at each cargo tank to drive the pump. The portable pumpdischarges through a flexible hose to a 6in (150mm) connection at each cargo pumpdischarge valve.

This is an abnormal operation and the risks involved should be assessed via thePTW System. For details of the operation refer to Part 2 Section 2 ProcedureNo 2/005.

Level in each tank is measured by a SAAB radar type level measuring transmitter

26-LIT-002 installed in the top of the tank. The transmitter also measures tankpressure and temperature at three levels within the tank. A second system,26-LZT-001, using Metritape provides an alternative level measurement. Thesecond system also provides a shutdown capability.

Three fixed tank washing machines are fitted to the roof of the tank allowing it to bewashed with either crude oil or water. The washing machines are isolated from thecrude oil washing header by manual Isolation Valves 26-GTV-001/002/035.

In the centre tanks there are additional washing machines, located on the tankbottom, to provide additional cover in areas not accessible to the main machines.






Facilities are provided to allow manual tank dips to be performed using the closedtank portable gauging system. The portable instrument can be mounted on 2 x 2inand 2 x 1in valves at deck level so that access is gained without venting the tank.This portable system can measure the oil level, the oil/water interface level and

temperature at any point over the depth of the tank.

The cargo tanks are coated with coal tar epoxy for the top 2m and the bottom3m, plus the upper side of all horizontal stringers. The remainder of the tank isuncoated. Sacrificial anodes are fitted based on the assumption that the bottom 1mof the tank being in contact with water 100% of the time.

COT No100% Capacity

(m3)98% Capacity

(m3)Pump Dry

(m3)

1P&S: T-2601C&A 18,740.2 18,365.4 0.5

1C: T-2601B 23,771.1 23,295.7 0.5

2P&S: T-2601F&E 21,086.4 20,664.7 0.5

2C: T-2601D 14,862.0 14,564.8 0.5

3P&S: T-2601I&G 21,086.4 20,664.7 0.5

3C: T-2601H 26,751.6 26,216.6 0.5

4P&S: T-2601L&J 21,086.4 20,664.7 0.5

4C: T-2601K 26,751.6 26,216.6 0.5

5P&S: T-2601O&M 21,082.7 20,661.0 0.5

5C: T-2601N 28,742.7 28,167.8 0.5

Table 2.1 – Crude Oil Tank Capacities

2.3 Cargo Reception Tank T-2601H (COT 3C)

Equipment Details

Tag Number: T-2601H

Capacity: 26,751.6m

3

Max OperatingPressure: 1400mm WG (1.4barg)

Minimum OperatingPressure: 400mm WG (0.4barg)

Refer to Figure 1.1, P&IDs BON-SHI-008-P-00002-013 Storage Compartment 5 andBON-SHI-008-P-00002-022 Storage Compartment 5 Tank Cleaning and Utilities.


Two cargo reception tanks are provided, T-2601H (COT 3C) nominated as theprimary and T-2601N (COT 5C) nominated as the backup if T-2601H is out of

service.






The tanks have all the same equipment as the cargo tanks described above inaddition to facilities required to perform reception duties.

Oil is loaded through the 20in (500mm) drop line which deposits the freshlyprocessed oil in the bottom of the tank.

Oil leaves the tank to adjacent tanks (COT 2C and 4C in the case of primaryreception, and COT 5P and 5S in the case of backup reception) through a 20in(500mm) cascade line which is 70% (24m) of the height of the tank. The cascadeline has a remotely operated Butterfly Valve 26-ZCV-101 controlled through theDCS. The valve position is indicated on the DCS.

The two centre tanks either side of the primary reception tank have lower transfervalves that will permit the free flow of crude oil from either centre tank into theadjacent wing tanks. It is intended that such an arrangement permit the ‘free flow’loading of crude and can minimise deep well pumping.

Process drains and overflow lines can flow to either the dirty slop tank or to the

reception tank. Initially these will be routed such that the drains will be routed to thedirty slop tank and the overflow routed to the reception tank. During later field lifewhen produced water rates increase it is likely that they will both be routed to 3C asthe ability of the dirty slop tank to handle them diminishes.

In the reception tank the process drains and overflow lines terminate at the bottomof the tank in seal pots 3m and 10m high respectively.

Separated water from the reception tanks is pumped by the Cargo Oil PumpP-2601H directly into the dirty slop tank via a dedicated oily water transfer line,for eventual disposal overboard.

In the event of a reception tank cargo oil pump failure, drain/free-flow transfer valves

26-ZCV-086/087 connected to the bottom transfer header are used to free flow thereception tank crude into an adjacent tank. The bottom header is kept as low aspossible to facilitate this transfer.

The primary reception tank is fully coated with pure epoxy. Sacrificial anodes arefitted based on the bottom 3m of the tank being in contact with water 100% ofthe time.

Number 5 COT centre tank is designated as the ‘backup’ reception tank with similarpiping and valve arrangements, coating and anodes.

2.4 Cargo Transfer Header

Oil from the crude oil pumps can be diverted from the transverse discharge manifoldfor a set of tanks through an isolation valve into the 20in (500mm) transfer header.The transfer header runs the length of the main deck to allow oil to be transferredbetween any tanks during loading and tank cleaning operations.






3.0 CONTROL AND INSTRUMENTATION

3.1 Control Overview

Refer to Figures 2.2 to 2.4, and P&IDs BON-SHI-008-P-00001-012 Position ofTank Gauging and Hand Dipping System, and BON-SHI-008-P-00001-024 StorageCompartment 7 Tank Cleaning and Utilities.

Cargo loading and associated de-ballasting operations are carried out in severalstages. For loading and offtake, the Trim and Stability Book places the cargo tanksin two groups. Group A comprises Crude Oil Tanks 2 and 4, and Group B comprisesCrude Oil Tanks 1, 3 and 5. However, any combination of tanks can be usedas dictated by operational requirements, provided trim and stress requirementsare met.

The loading sequence for the FPSO is dictated by the maximum availableproduction rate of crude oil and the expected offloading schedule from the FPSO to

the offtake tanker.Following offtake, the cargo tanks are not normally completely stripped empty andwill have a remaining level of around 1%. Cargo Offtake takes place when at least75% of the one million barrel (159,000m3) parcel is available.

Variation in the weight of consumables, such as diesel and freshwater, stored at theaft end of the vessel, also affect the trim and to a lesser extent stability of the vessel.Changes to the weight of consumables is balanced by adjusting the weight anddistribution of ballast.

Tank loading valves are remotely controlled from the Central Control Room (CCR)with the tank levels monitored by the SAAB radar system. Tanks should normallybe loaded with the production initially going to the reception tank and the oil thenbeing distributed to the other tanks either by pumping or through a network ofinter-tank sluice valves.

Prior to each loading/unloading operation, a loading or unloading plan will be issuedby the Marine Supervisor.

The cargo oil tanks are provided with SAAB radar level gauges fitted to the maindeck in the respective tanks. The analogue signals from the radar beams reflectingoff the liquid within the cargo tanks are passed from the local instrumentation to theDCS and NAPA System in the control room.

The cargo tanks are additionally provided with deck-mounted temperaturetransmitters. The temperature transmitters consist of three temperature probes of

lengths corresponding to lower, middle and upper levels of each cargo tank. A pressure transmitter is incorporated within the SAAB unit, giving a read out of thepressure within the individual tanks.

The temperature and pressure transmitter signals are linked with the radar ullagesignals from each cargo tank and pass jointly back to the DCS System.

It is essential that cargo loading and de-ballasting is accomplished in the correctsequence to maintain vessel stability and provide for acceptable bending momentsand shear forces on the FPSO.

The loading computer interfaces with the DCS to ensure that the cargo loadingprogram or discharge program is monitored safely and will alarm if the actual

operation differs significantly from the plan.






In general, the cargo tanks will be loaded to a maximum 95% capacity but inexceptional circumstances this can be increased to 98%, in which case it must becarefully monitored.

3.2 Tank Level GaugingThe cargo, slop, chemical and diesel tanks are provided with SAAB tank radar levelgauge system as the ‘primary’ level sensing system. This integral system consists ofradar level transmitter, IG pressure transmitter and three sets of temperaturesensors for each tank (eg 26-LIT-002, 26-PT-001 and 26-TT-001-003 for COT 1P).These signals are interfaced to the DCS via a serial link and used formonitoring/alarming.

The tank radar is an intrinsically safe system with a narrow beam parabolic antennalocated on the tank top, which measures the ullage distance from the transmitter tothe liquid surface.

It is hardwired to the central Level Unit (LU), which is located in the CER andcommunicates via a serial interface connection to the DCS. The LU serial linktransmits level, pressure and temperature data to the DCS, as well as the status ofthe equipment for alarm purposes.

Using the SAAB radar transmitters, the level in the storage tanks is measured asullage, which is the distance from the top of the tank to the top of the liquidmeasured in metres.

All tank levels will be displayed in ullage on the tank monitoring screens. The samedata is also to be used to display the level (0 to 100%) on the process screens.Level is the measured linear value as a percentage of the measured rangeie 0 to 100%.

The SAAB system provides a high level alarm when the tank level exceeds 95% anda low level alarm when the tank level falls below 5%.

The Pt100 Temperature Detectors are installed in a stainless steel guide pipe.To provide accurate data, three separate temperature elements are installed perguide pipe. Each tank therefore has three temperature readouts: at the top (27.3m),middle (16.8m) and bottom (5.8m). All cargo and slop tank temperatures aredisplayed on the DCS.

A pressure transmitter is fitted on the top of each cargo tank and both slop tanks tomonitor the operating pressure of the tanks. All individual cargo and slop tankpressure readouts can be displayed on the DCS though normally the common

system pressure only will be displayed. A Metritape liquid level sensor (eg 26-LZT-001 for COT 1P) is fitted, mounted in atube with the termination on the top of the tank. The system uses a pressuresensitive tape that varies in resistance according to submerged length.

The resistance signal provides a level indication which gives a high level alarmwhen the tank level exceeds 95% and a high-high level (safety) alarm when the tanklevel exceeds 98% of capacity. This system is totally independent of the radargauges and is connected directly to the SSDS.

Signals from the level transmitter are also fed to the load computer which calculatesvolume and makes corrections for list and trim.






When the tank level reaches 98%, a high level alarm is initiated in the DCS and thetank loading valve will close to prevent further loading into the tank. The valvecannot be re-opened until the level is below 94%.

Reception tank COT 3C is equipped with a Halla Oil/Water Interface LevelTransmitter 26-LZT-037. This provides interface level indication and a high levelalarm on the DCS to an accuracy of +/-0.5%.

InstrumentTag Number

Low LowTrip

Low Alarm High AlarmHigh High

TripControllerSet Point

Cargo Tank No 1 Port

26-LIT-002 4% 96%

26-PT-001 -100mmwg 1200mmwg

26-LZT-001 95% 98%

Cargo Tank No 1 Centre

26-LIT-004 4% 96%

26-PT-002 -100mmwg 1200mmwg

26-LZT-003 95% 98%

Cargo Tank No 1 Starboard

26-LIT-006 4% 96%

26-PT-003 -100mmwg 1200mmwg

26-LZT-005 95% 98%


26-LIT-008 4% 96%

26-PT-004 -100mmwg 1200mmwg

26-LZT-007 95% 98%


26-LIT-010 4% 96%

26-PT-005 -100mmwg 1200mmwg

26-LZT-009 95% 98%

Table 2.2 – Cargo Tank Alarm and Trip Settings







Low LowTrip




26-LIT-012 4% 96%

26-PT-006 -100mmwg 1200mmwg

26-LZT-011 95% 98%


26-LIT-014 4% 96%

26-PT-007 -100mmwg 1200mmwg

26-LZT-013 95% 98%


26-LIT-016 4% 96%

26-PT-008 -100mmwg 1200mmwg

26-LZT-015 95% 98%


26-LIT-018 4% 96%

26-PT-009 -100mmwg 1200mmwg

26-LZT-017 95% 98%


26-LIT-020 4% 96%

26-PT-010 -100mmwg 1200mmwg

26-LZT-019 95% 98%


26-LIT-022 4% 96%

26-PT-011 -100mmwg 1200mmwg

26-LZT-021 95% 98%

Table 2.2 – Cargo Tank Alarm and Trip Settings (cont’d)







Low LowTrip




26-LIT-024 4% 96%

26-PT-012 -100mmwg 1200mmwg

26-LZT-023 95% 98%


26-LIT-026 4% 96%

26-PT-013 -100mmwg 1200mmwg

26-LZT-025 95% 98%


26-LIT-028 4% 96%

26-PT-014 -100mmwg 1200mmwg

26-LZT-027 95% 98%


26-LIT-030 4% 96%

26-PT-015 -100mmwg 1200mmwg

26-LZT-029 95% 98%

Table 2.2 – Cargo Tank Alarm and Trip Settings (cont’d)

3.3 NAPA Loading Computer

Refer to P&ID BON/1DA2617/SAAB/000001 Load Computer.

The ‘Onboard NAPA’ software allows loading and unloading plans to be developedby the Marine Supervisor. The plans detail the magnitude of liquid volumes andsequencing transfer to and from the tanks, eg loading from the topsides process and

unloading to the offtake tanker with concurrent ballasting/de-ballasting as required.Onboard NAPA is run in two separate locations; on a standalone PC situated in theMarine Supervisor’s office and on an identical online PC located in the CCR.The NAPA software does not perform control functions and is only used formonitoring, alarm generation and reporting. The same software version is loaded inboth PCs and in the event of failure of the CCR PC it can be replaced by theother one.






The loading and unloading plans are developed on the standalone copy of thesoftware and transferred, by disk, to the DCS server mounted in the CCRengineering console.

The ‘Onboard NAPA’ program in the CCR PC monitors the vessel draft, the levels,pressures and temperatures in the cargo, ballast, clean and dirty slops, methanol,chemical, diesel and freshwater storage tanks. The vessel dimensions, lightweightvalues and capacities of all of the tanks are built into the loading computer software.The software uses these values as inputs to a vessel model and calculates thevarious stability and stress values for the ship at all times. It is essential that theoperator maintains each of these parameters within safe limits at all times.

The ‘Onboard NAPA’ is a computerised version of the Class Approved Stability andStrength Manuals and is always consulted prior to moving cargo or ballast volumes.

The ‘Onboard NAPA’ is frequently referred to during the execution of theseoperations to ensure that the operation is going to plan with respect to structural

limitations and stability.The Trim and Stability Book provides calculation data and methodology for manualcalculation of the data, which the loading computer provides. The booklet alsocontains a number of standard conditions, which Bonga FPSO will often load andmust always be referred to in the event of non-availability of the loading computer.

Although the same software configuration runs on both machines, the NAPAgenerated alarms from the online system in the CCR are displayed on the CCRPC only. The standalone PC in the Marine Supervisor’s office is updated every30 minutes from the CCR PC.

The measured tank level data is provided over a serial link from the SAAB tankgauging system; the SAAB unit also sends the tank level data to the DCS via a

separate data link. Alarms generated within NAPA are routed via the SAAB unit tothe DCS for annunciation and logging.

Although tank level measurements are normally online inputs, it is possible to inputtank levels manually in the event of a communication or equipment failure. For thispurpose manual dips can be taken on deck through the closed hand dipping systemusing a portable tank gauging tape.

The aft MMC 2in dipping point on each cargo tank is designated as the tank datumpoint, and all SAAB and Metritape readings are corrected to this datum. Valuesobtained in this way can then be entered manually into the load computer.

Note: Prior to commencing the loading sequence, all crude oil loading and

discharging operations must be fully simulated on the loading computer. A safe loading plan must be drawn up, agreed and fully understood by all personnel involved in loading operations. The cargo loading operation iscarried out from the control room.






3.3.1 NAPA Operator Interface

The NAPA PC located on the operator console in the CCR is the primary operatorinterface for the loading computer and allows access to all NAPA displays providedincluding the following:

NAPA controls on the PC:

• Develop Loading Plan

• Initiate Stability Calculations

• Start Loading Plan Monitoring

• Access Menus for Tank Loading, 3D model etc

Indication from NAPA on the PC:

• Load Tanks

•Load Stores

• Draft Survey

• GM Required

• Grade Database

The DCS replicates the displays used in the SAAB cargo monitoring system whichincludes:

• Tank ullage, corrected for trim and list

• Tank temperatures, top, middle and bottom

•

Ship trim and listThe following NAPA vessel monitoring alarms are available:

• GM

• Bending Moment

• Shear Force

• Trim

• Mean Draft

Reports generated in the NAPA software package are available for printing on the

report printer on the LAN. The following reports are available from the package:• Tank Report

• Stability Report

• Longitudinal Strength Report

• Cargo History Report

• Tank Inspection Report

• Damage Case Report

All displays provided with the NAPA package are available for viewing via the server

interface to the DCS.






3.4 Cargo Loading Control

Cargo from the topside process is normally loaded from 25-MOV-401 to the loadingheader through 26-ZCV-009 and 26-ZCV-018/020 into the reception tank COT 3C orthrough 26-ZCV-022 and 26-ZCV-027/029 to the alternate reception tank COT 5C.

The cargo normally flows from the 3C reception tank out the overflow line at 70%tank level through 26-ZCV-101 to the required tanks through the cascade lines into2C (via balancing Valves 26-ZCV-087/088) or 4C (via 26-ZCV-085/084). The pathfrom the alternate reception tank 5C (when used) is out its overflow line at 70% tanklevel through 26-ZCV-102 to the required tanks through cascade lines into 5P viabalancing valves 26-ZCV-103/104 or 5S via 26-ZCV-105/106.

The hydraulically actuated valves are controlled from the DCS, where valve status isalso displayed.

During startup, valves in the loading header between topsides production facilitiesand the hull storage tanks must be aligned to provide an open flow path.

Opening of routing valves such as the Main Inlet Header Valve 25-MOV-401 mustbe co-ordinated with the overall production startup procedure and controlsequences. The operator must ensure that at least one valid combination of openvalves to at least one cargo tank.

When the loading operation is in progress, the Isolation Valve 25-MOV-401 betweenthe Topsides Crude Coolers E-2540A/B/C and the loading header must be open.If the operator attempts to close this valve, a message ‘Closing this valve will shutdown production’ will appear. The operator must confirm the action before the closecommand will be sent to the valve.

The operation of the cargo tank balancing valves will be a manual operator action

from the CCR, which will allow transfer of cargo between the tanks. There are nointerlocks identified for these valves.

3.5 Cargo Transfer

3.5.1 Pump Operation

The cargo pumps can be used to transfer from any tank directly into the transferheader, and then into any other tank, pigging system, slop system, crude oilwashing and tank cleaning system.

Operation of the pumps when used for cargo transfer is from the individual pumpoverlay on the DCS.

Note: The tag numbers in the descriptions below are for cargo tank 1P. Refer toP&IDs for equivalent tags for other tanks.

To start the pump from the individual pump overlay, after pressing the ‘Pump Start’for P-2601C, the DCS will start the pump and set the pump speed to 5% through54-SY-202. When the pump is confirmed running determined from the DischargeLine Pressure Transmitter 26-PIT-018 being greater than 0.5barg (initially settingconfigurable) the Pump Discharge Valve 26-ZCV-031 will be opened.

If the pump fails to start the discharge valve will stay closed. Stopping the pump willclose the discharge valve and ramp the pump speed down to 0% after a time period.

When a pump has been selected to start from the overlay, the relevant discharge

valve is put into ‘auto’ without prompting the operator for confirmation.






3.5.2 High Tank Level

When the level in a tank, eg COT 1P 26-LIT-002, reaches 98%, a high level alarm isinitiated in the DCS and the Tank Loading Valve 26-ZCV-011, will be closed by theapplication to prevent further loading into that tank. The valve cannot be reopeneduntil the level falls below 94%.

Note: A 2% hysteresis (configurable) is included to prevent cycling of the valvearound the alarm set point.

CargoOil Tank

No

Cargo PumpDischarge

Valve

Cargo PumpDischargePressure

Cargo PumpSpeed Control

Inlet ValveTransfer/Load

Line

1P ZCV-031 PIT-018 SIC-202 ZCV-011

1C ZCV-032 PIT-019 SIC-203 ZCV-012

1S ZCV-033 PIT-020 SIC-204 ZCV-012

2P ZCV-034 PIT-021 SIC-205 ZCV-015

2C ZCV-035 PIT-022 SIC-206 ZCV-016

2S ZCV-036 PIT-023 SIC-207 ZCV-017

3P ZCV-037 PIT-024 SIC-208 ZCV-019

3C ZCV-038 PIT-025 SIC-209 ZCV-020

3S ZCV-039 PIT-026 SIC-210 ZCV-021

4P ZCV-043 PIT-027 SIC-213 ZCV-024

4C ZCV-044 PIT-028 SIC-214 ZCV-025

4S ZCV-045 PIT-029 SIC-215 ZCV-026

5P ZCV-046 PIT-030 SIC-216 ZCV-028

5C ZCV-047 PIT-031 SIC-217 ZCV-029

5S ZCV-049 PIT-032 SIC-218 ZCV-030

Table 2.3 – Associated Tag Numbers for COT






3.6 Operator Interface for Loading Operations

The DCS HMI located in the CCR is the primary operator interface.

Figures 2.2 and 2.3 at the end of this section illustrate cargo handling graphical

interface screens.

A list of operator controls and indicators is shown below:

• Control from the HMI

− Control and feedback setting of each pump hydraulic valve

− Starting of pump (set output to 5%)

− Stopping of pump (set output to 0%)

− Open and close commands for each on/off valve

− Position setting and indication for proportional control valves

− Manual override facility

− Activate synchronisation

− Cascade control from topsides booster pumps suction (27-PIC-407)

• Indication on the HMI

− Interlock status of each valve

− Interlock status of each pump

− Level indication of each cargo and slop tank

− Valve position indication

− Pump running indication

− Discharge pressure (used as pump running indication) for each pump

− Interface level in slop tanks and reception tank 3C

− Indication of IGG clean and dirty header pressures

− Indication of N2 header pressure

− Transfer and discharge header pressure

• Local Control (at the Framo Control Unit)

− Start and stop of the pumps by setting pump flow control valve to a position

between 0 to 100%






3.7 Cargo Pump Interlocks

Tag No/Pop-up

Message Function Description

P-2601A to O Pumps will not start if any one of the following four interlocksare present.

Oil Transfer/Discharge ValveRouting

The discharge or transfer header isolation valves relevant tothe pump are closed, eg pumps P-2601A/B/C = 26-ZCV130or 131 (refer to Part 1 Section 3 Table 3.2 for equivalentvalves for other pumps).

Hydraulic HPU All power packs are stopped (54-YS-201A to 209A), eg thepump HPU is not running.

Valve HPU When both (54-YA-001 and 54-YA-002) are failed or anyone of the common system alarm 54-YA-003 to 007 ispresent, eg the Valve HPU is not healthy.

Header IsolationValves

26-SDV-122 to 125 are not closed.

Table 2.4 – Startup Interlocks (STIL) – Cargo Pumps P-2601A to O

Tag No/Pop-up

Message

Function Description

54-YZC-101(1) P-2601A to C – Pump trip immediately stops pumps(54-SY-202 to 204 output = 0%) and prevents pumpfrom starting.

54-YZC-101(1) P-2601D to F – Pump trip immediately stops pumps(54-SY-205 to 207 output = 0%) and prevents pumpfrom starting.

54-YZC-101(1) P-2601G to I – Pump trip immediately stops pumps(54-SY-208 to 210 output = 0%) and prevents pumpfrom starting.

54-YZC-101(1) P-2601J to L – Pump trip immediately stops pumps(54-SY-213 to 215 output = 0%) and prevents pumpfrom starting.

54-YZC-101(1) P-2601M to O – Pump trip immediately stops pumps(54-SY-216 to 218 output = 0%) and prevents pumpfrom starting.

54-YZC-101(1) P-2603 – Pump trip immediately stops pumps (54-SY-219output = 0%) and prevents pump from starting.

Table 2.5 – Process Interlocks for Cargo Pumps P-2601A to O






Tag No/Pop-upMessage


54-YZC-101(1) P-2605B – Pump trip immediately stops pumps (54-SY-220output = 0%) and prevents pump from starting.

54-YZC-101(1) P-2605A – Pump trip immediately stops pumps (54-SY-221output = 0%) and prevents pump from starting.

54-YZC-101(1) P-2602 – Pump trip immediately stops pumps (54-SY-222output = 0%) and prevents pump from starting.

Notes:

(1) 54-YZC-101 is the trip signal from the SSDS to the HPU to trip the hydraulicsupply feeding the cargo/slop pumps, this signal will also be used to drive the

pumps to 0%.(2) Low Low Pressure 55-PZLL-101 and 55-PZLL-102 on the CIGM and DIGM,

respectively, trips the cargo, slop and skimming pumps and shuts the mainoil export ESD Valve 26-SDV-121 (tandem offloading) and ESD Valves27-SDV-454/464/474 (SPM offloading). During periods when the CIGM is notin use, the output from 55-PZT-101 should be inhibited from taking anyexecutive action.

Table 2.5 – Process Interlocks for Cargo Pumps P-2601A to O (cont’d)

4.0 SAFEGUARDING

Protection against potential overfilling of the cargo oil tanks and slop tanks isprovided by the high level alarm and trip signal from the Metritape system. The setpoints for all of the cargo and slop tank high level alarms is 95% and the trip signalis provided at 98% of the tank capacity.

The activation of the high level alarm is annunciated in the DCS.

The activation of the high level trip is annunciated in the DCS and initiates closure ofthe Tank Loading Valve (26-ZCV-011 for COT 1P) and stops the cargo oil pumpbeing used in the case of cargo transfer. The loading valve cannot be re-openeduntil the level is below 94%.

The transfer and discharge headers are shut in on an ESD. To ensure that pressure

in the headers does not increase in this situation due to a heat source or fire in thevicinity of the lines, each header has a Fail Open Valve 26-SDV-122 and26-SDV-123, for the transfer and discharge headers respectively located at the aftend of the headers. The valves drain the headers to either the reception tank COT5C or the dirty slop tank.

A similar arrangement is provided at the forward end of the headers with26-SDV-124 and 26-SDV-125, for the transfer and discharge headers respectively.The valves drain the headers to either the COT 1P or COT 1S.





Shell Nigeria E&P Company Limited Bonga FPSO Plant Operating Procedures ManualVolume 4 – Oil Storage, Handling and Ballast Systems

Hydraulic ValveHPU

Hydraulic HPU

034

(2P

035

(2C

036

(2S

037

(3P)T-2601I

083082

043

(4P) T-2601L

040

(3C) T-2601H

084

094

044

(4C) T-2601K

039

(3S) T-2601G

090 089

045

(4S) T-2601J

096

098

100

081080

088

087

079

120 119

046

(5P) T-2601O

049

(5S) T-2601M

104

095

099

093 0106

0091103

101

038

P-26P-2601IP-2601LP-2601O

P-26

P-2601H

P-2601K

085

086

047

(5C) T-2601N

102

048

P-2601N

107 105

092 0

P-2601GP-2601JP-2601M P-26

097

PIT- 030 PIT-027 PIT-024 PIT-02

PIT-0

PIT-025

PIT-028 PIT-031

PIT-032 PIT-029 PIT-026 PIT-0

LIT-0 26

XXX%

LZT-025 LIT-020

XXX%

LZT-019 LIT-014

XXX%

LZT-013 LZT-00

LZT-00LIT-022

XXX%

LZT-021

LIT-028

XXX%

LZT-027

LIT-030

XXX%

LZT-029 LIT-024

XXX%

LZT-023 LIT-018

XXX%

LZT-017 LZT-0

LIT-016

XXX%

LZT-015

LZT-037

Pick box toCargo_Hdr_SD

Slops

XXX barg XXX barg XXX barg XXX

XXX

XXX barg

XXX bargXXX barg

XXX barg XXX barg XXX barg XX

(Slops_SD)

Slop Tanks

xxx54-SIC-216 xxx54-SIC-213 xxx54-SIC-208 54-SIC

xxx

54-SIC-209

54-SI

xxx54-SIC-210 54-SIxxx54-SIC-218 xxx54-SIC-215

xxx

54-SIC-217xxx54-SIC-214

55-PIT-104

bargXXX

Dirty IGGHeader

55-PIT-103

bargXXX

Clean IGGHeader

55-PIT-001

bargXXX

N2 Header

042

041

Running/Stopped

Running/Stopped

(Slops_SD)

0%

70%

0%

70%


OPRM-2003-0304 Page 21 of 22

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Shell Nigeria E&P Company Limited Bonga FPSO Plant Operating Procedures ManualVolume 4 – Oil Storage, Handling and Ballast Systems


OPRM-2003-0304 Page 22 of 22

Printed copies of this document may be obsolete. ‘Business Control Documents’ are online in SNEPCO Livelink.

CARGO SLOP DIESEL CHEMICALMETHANOL

FRESH

WATER DRA

SENS

(4

BALLAST

Note 3

AP I-14C TA NK S

PRIMARY SYSTEM - SAAB

BACK-UP SYSTEM -

METRITAPE

C

SAAB

METRITAPE

4 TANKS 14 TANKS

2 TANKS 2 TANKS15 TANKS 4 TANKS

NON-API-14C TANKS & DRAFT

PRIMARY SYSTEM - METRITAPE (VIA SAAB)

BACK-UP SYSTEM - DREXEL BROOKS

NOTE THAT METRITAPE SIGNALS TO SAAB VIASERIAL LINK ARE "CORRECTED" SIGNALS.

PRIMARY

BACK-UP BACK-UP BACK-UP BACK-UP

PRIMARY PRIMARY PRIMARY

PRIMARY PRIMARY

BACK-UP

PRIM

NAPALOAD

COMPUTER

#1

Notes

1) The hardwired signals between the Metritape Vangaurd system &

SSDS are the back-up signals from the Cargo/Slops/Diesel/Chemical

tanks.

2) The serial signals between the Metritape Vangaurd system &

SAAB are the primary signals from the Draft Readings/Fresh Water/

Ballast tanks.3) Drexel Brooks (4-20MA)





Section 3Detailed Description – Ballast System

Table of Contents

1.0 INTRODUCTION.............................................................................................................3


2.1 Ballast Tanks.......................................................................................................3

2.2 Ballast Pumps P-5804A to D...............................................................................6

2.3 Ballast Valves......................................................................................................7


3.1 General................................................................................................................8

3.2 Ballast Tank Gauging ..........................................................................................8

3.3 Ballast System Controls .................................................................................... 10

3.4 De-ballasting......................................................................................................13

3.5

Ballasting...........................................................................................................15

3.6 Ballast Line Surge Protection ............................................................................ 16

3.7 Manual Override................................................................................................17

3.8 Header Isolation Valves.....................................................................................17

3.9 Ballast Pump Discharge Valves ........................................................................ 18

3.10 Hydraulic System Capacity................................................................................18

3.11 Tank Cleaning/Transfer Main ............................................................................ 18

3.12 Interlocks ........................................................................................................... 19

3.13

Logic Conditions................................................................................................22

4.0 SAFEGUARDING.........................................................................................................23

Part 1 Section 3 Detailed Description – Ballast System





Table of Contents (cont’d)

TABLES

Table 3.1 – Ballast Tank Details...............................................................................................5

Table 3.2 – Ballast Water Tank Alarm and Trip Settings .........................................................9

Table 3.3 – Ballast Water Pump Alarm and Trip Settings ...................................................... 12

Table 3.4 – Tag Nos for Ballast Pump Valves and Instrumentation.......................................14

Table 3.5 – Ballast Water Header Alarm and Trip Settings....................................................17

Table 3.6 – Common Start Interlocks for Ballast Pumps (P-5804A/B/C/D)............................ 20

Table 3.7 – Start-up Interlocks – Ballasting or De-ballasting (P-5804A and B)...................... 20

Table 3.8 – Start-up Interlocks – Ballasting or De-ballasting (P-5804C and D) ..................... 21

Table 3.9 – Start-up Interlocks – Tank Cleaning (P-5804C and D)........................................21

Table 3.10 – Process Shutdown Logic...................................................................................22

Table 3.11 – Header Flooding Logic ......................................................................................22

Table 3.12 – Abnormal Conditions Logic ............................................................................... 22

FIGURES

Figure 3.1 – Graphical Interface – Ballast Facilities............................................................... 24






1.0 INTRODUCTION

The Ballast System provides the distribution of seawater ballast throughout theFPSO, under varying load conditions. To comply with IMO requirements thesegregated seawater Ballast System is completely separate from the Crude OilStorage System.

The stress and bending moments applied to the vessel hull and the FPSO trimare affected by cargo oil loading, offloading, bunkering, fuel oil transfer andconsumption. The Ballast System consists of a ring main, hydraulically drivenpumps and tank isolation valves. Vessel ballast level is remotely controlled from thePSCS operator workstations located in the CCR. Operation/control can also beachieved from the Framo control panel located in the valve cabinet room in ‘A’ deckof the accommodation. The Loadmaster Computer is used to simulate changingloading conditions and predict ballast requirements.

Refer to P&IDs:

• BON-SHI-008-P-00002-001 Ballast System (1/3)



• BON-SHI-008-P-00002-004 Air and Sounding System (1/2)


2.1 Ballast Tanks

Refer to Figure 1.2 and P&ID BON-SHI-008-P-00002-001/2/3 Ballast System.

Equipment Details

The Ballast Wing Tanks are located along the outside of the Crude Oil Tanks thusaffording some collision damage protection for the containment of the hazardouscrude cargo. Six tanks down each flank of the vessel store varying volumes ofballast to help maintain the trim, list and stress condition of the vessel.

In addition, there are two ballast tanks located at the forward and aft ends of thevessel, which are the Fore and Aft Peak Tanks. The peaks are used as normalballast tanks, holding various quantities of water at different stages of the loadingand unloading sequences. Submerged Ballast Pumps are located in the WaterBallast Tanks No 4 Port and Starboard.

Each group of six ballast tanks, either port or starboard, has a ballast main runningthrough them fore to aft which can draw suction from all six tanks in the group.The fore and aft peak tanks are served by both port and starboard ballast mains.The piping system allows ballast water to be pumped or flowed by gravity into thetanks. The ballast mains are interconnected in the forepeak tank, which will alsoallow the pumps on one side of the vessel to pump via the ‘ring main’ from/into atank on the opposite side of the vessel.

The internals of all ballast tanks are fully coated with tar-free epoxy paint and fittedwith cathodic protection based on the bottom 3m of the tank being submerged100% of the time and the remainder of the tank being submerged 70% of the time.To minimise corrosion, all ballast piping located in the ballast wing tanks

is manufactured from reinforced glass-fibre piping, except for the tankpenetration pieces.






In order to control trim, list and stability, it is necessary to discharge and refill theballast tanks with seawater as the quantity of cargo changes.

Before the start of oil production and after each shuttle tanker offloading, the waterballast tanks will normally contain water and will be discharged (de-ballasted) as thecargo tanks are gradually filled. Ballast is taken onboard again during the offloadingoperation.

Ballast Wing Tanks 4S and 4P each contain two ballast pumps which are used tomove ballast around the system via the ballast mains.

The ballast system is used to supply water to the suction of the tank cleaning pumpwhen water washing of tanks is required. The system can also supply water into thetransfer main if water is required to put into the cargo or slop tanks. The port sideand starboard side ballast system has an emergency inert gas connection, from theclean inert gas main for filling the ballast mains and any damaged tanks with inertgas. The above three connections have removable spool pieces that are normally

only fitted when required and removed after use. All normal ballasting and de-ballasting operations can be carried out from the DCS,using the remotely operated hydraulic valves.

Seawater level in the ballast tank is measured using a metritape type system asprimary and RF capacitive probes system as backup. Level transmitters providelevel signals to the DCS and loading computer, and are equipped with high levelalarm set at 95% volume and a trip set at 98% volume. Activation of either alarm isannunciated on the DCS.

Deck standpipes are provided for manual tank soundings to be obtained using theportable tank gauging tape in the event of failure of the metritape type and RFcapacitive probes system.

Any pressure buildup in the tank is vented to atmosphere via four sets of ball floatvent valves.






Ballast Tank Valves Capacity

Fore Peak WBSTT-5801A

58-ZCV-139 Main58-ZCV-140 Main58-ZVC-141 Port Crossover58-ZVC-142 Stbd Crossover58-ZCV-151 Ballast Main Vent Valve

28699.6

No 1 WB Tank PortT-5801B

58-ZCV-115 Main58-ZCV-116 Stripping

6905.5

No 1 WB Tank StarboardT-5801C


6905.5

No 2 WB Tank PortT-5801D


7767.6

No 2 WB Tank StarboardT-5801E


7767.6

No 3 WB Tank PortT-5801F


17107.4

No 3 WB Tank StarboardT-5801G


17107.4

No 4 WB Tank PortT-5801H

58-ZCV-127 Main58-ZCV-128 Stripping58-ZVC-147 Port Main Isolation

58-ZVC-101 Sea Chest Valve58-ZVC-102, 105 Sea Chest to Pump Suct58-ZVC-103, 106 Pump Suction58-ZVC-104, 107 Discharge to Main58-ZVC-145 Pump Disch Overboard58-ZCV-149 Discharge to Main

7761.4

No 4 WB Tank StarboardT-5801J

58-ZCV-129 Main58-ZCV-130 Stripping58-ZVC-148 Stbd Main Isolation58-ZVC-108 Sea Chest Valve58-ZVC-109, 112 Sea Chest to Pump Suct

58-ZVC-110, 113 Pump Suction to Main58-ZVC-111, 114 Discharge58-ZVC-146 Pump Disch Overboard58-ZCV-150 Discharge to Main

7761.4

No 5 WB Tank Port T-5801K 58-ZCV-131 Main58-ZCV-132 Stripping

7735.3

No 5 WB Tank StarboardT-5801L


7735.3

No 6 WB Tank Port T-5801M 58-ZCV-135 Main58-ZCV-136 Stripping

2428.5

Table 3.1 – Ballast Tank Details






Ballast Tank Valves Capacity

No 6 WB Tank StarboardT-5801N


2428.5

Aft Peak Tank T-5801P 58-ZCV-143 Main58-ZCV-144 Main

9891.8

Note: The atmosphere of all Ballast Tanks is automatically sampled by the Omnicronsampling system to detect hydrocarbon gas. This gives an indication of oilcontamination of the ballast system.

Table 3.1 – Ballast Tank Details (cont’d)

2.2 Ballast Pumps P-5804A to D

Equipment Detail

Type: SB600

Capacity: 2000m3/hr

Discharge Pressure: 3bar(g) (Differential)

Head/Specific Gravity: 30m at rated speed/1.025

Motor: Hydraulic high-pressure motor

Tank Depth/PumpLength: Approximately 32/31.639m

Pump housing Material: Stainless Steel AISI 316

Pump shaft Material: Mild Steel (protected from seawater)

Material Impeller: Seawater-resistant Bronze

Material CofferdamPipe Stack: Stainless Steel AISI 316 Mechanical Type


Refer to Figure 1.2 and P&IDs BON-SHI-008-P-00002-002 Ballast System andBON/1JA0980/FRANK/000003 Ballast Pump.

Seawater for ballasting is taken onboard the FPSO via the Port and Starboard seachests. Both independent sea chests are manually treated with sodium hypochloritefrom Steel Drum Tank T-5804A/B located on the main deck port and starboard,for the control of marine growth. Refer to POPM Volume 21 Seawater System(OPRM-2003-0321) for details of the sodium hypochlorite system. Port andStarboard Ballast Lines are used to distribute the ballast water to the six sets ofWing Ballast Tanks, the Aft and Fore Peak Tanks.

The vertically mounted centrifugal water Ballast Pumps P-5804A/B/C/D aresubmerged pumps located in No 4 Starboard (P-5804C/D) and No 4 Port(P-5804A/B) Ballast Tanks. The Ballast Pumps are self-priming pumps driven byhydraulic motors in the Ballast Tank. Downstream of the suction valves, an inlinefilter, P-5804A/B/C/D-S-01 is fitted on the pump suction line to remove any

extraneous material from the seawater passing to the pump suction.






All submerged pump controllers are calibrated from a minimum output where thehydraulic supply pressure to the pump motor is 0bar(g) to a maximum output of260bar(g).

In practice the submerged Ballast Pumps are never operated with the hydraulicsupply pressure for the pump motor set below 60barg.

If the ballast pumps are controlled from the DCS System, the set point from the DCSConsole is used by the PLC logic incorporated in the Framo Control Panel to adjustthe hydraulic supply to the pump motor.

To ensure a smooth start-up of the ballast pumps, the set point is limited to 60bargfor 45 seconds. When this time period has elapsed, the hydraulic supply pressurewill increase to match the required set point.

A manually operated flow control valve is provided for the hydraulic supply to thesubmerged pump motor. The valve is mounted on the top-plate of the ballastpumps. The flow control valve is always set to the fully closed position of the ballast

pumps and controlled from the DCS Console.

During ballasting operations, the ballast pumps are normally operated from the DCSConsole but during an emergency the pumps can be operated locally at the FramoControl Panel.

Pressure transmitters are installed on the pump suction line either side of the inlinefilters to warn of impending filter blockage. The readings from the pressure sensorsare processed by the DCS and a high Differential Pressure alarm given at 1bar.

Seawater is passed from/to the discharge lines of the Ballast Water Pumps at up to5.0barg during Ballasting/De-ballasting Operations.

2.3 Ballast ValvesThe Ballast Main, and dedicated lines to/from the ballast tanks, ensures thatseawater may be passed into any of the Ballast Tanks for ballasting, or pumpedoverboard during de-ballasting operations.

A crossover line installed in the Fore Peak Water Ballast Tank enables the port andstarboard mains to be made common. The crossover line is fitted with the IsolationValves 58-ZVC-141 and 58-ZVC-142, which are normally in the closed position.

All wing ballast tanks are fitted with one 20in main suction and one 10in strippingsuction valve. The Fore and Aft peak tanks each have two 20in main suctions.

With the exception of Nos 5 and 6 port and starboard, all suction valves are located

in tanks adjacent to the ones they serve. This is in order to enable access to thevalves for maintenance in the event of failure with ballast in the tank, when theadjacent tank can be emptied to allow access to the valve.

All the valves used in normal ballasting operations can be remotely operated fromthe CCR through the DCS and, if necessary, operated manually by portablehydraulic hand pumps or remotely at the solenoid valve cabinets in the valve controlcabinets on ‘A’ deck.

The valves are of the butterfly type (rubber lined) with rotary hydraulic actuatorsmounted directly on the valve bodies, with position feedback through flowmeters inthe individual hydraulic lines. All remote valves are potentially submerged in theballast tanks.







3.1 General

The ballast adjustment requirements for Bonga FPSO is determined by the MarineSupervisor when developing the loading or discharging plans. These plans aredeveloped on the loading computer using the levels on the 15 Cargo Oil Tanks fromthe Saab radar-based Cargo Monitoring System and the level in the ballast watertanks measured by the Metritape level monitoring system.

3.2 Ballast Tank Gauging

Refer to Figure 3.1 and P&IDs BON/1DA2177/SAAB/000002 COT Level GaugingSystem and BON/1DA2160/CONSILIUM/000001 Remote Sounding System(Ballast FO).

The 14 ballast tanks are provided with the Metritape Vanguard system as the

primary sensor. These are connected through a serial link to the Saab system,which provides level and draft correction, and then by serial link from Saab to theDCS to provide all Metritape data to DCS.

All tank levels are displayed in ullage (the distance from the bottom of the tank to thetop of the liquid in metres) on the tank monitoring screens. The same data will alsobe used to display the level (0 to 100%) on the process screens. The level is themeasured linear value as a percentage of the measured range, ie 0 to100%.

The ballast tanks are provided with RF capacitance type Drexell Brookstransmitters. These transmitters are back-up sensors for the primary Metritapesensors and provide the high level alarms independently of the Metritape. They aredirectly wired to SSDS.

The Aft Peak Tank is provided with DP type Rosemount level transmitter as aback-up to the primary Metritape sensor to provide an independent high level alarmand for the SSDS.







Low LowTrip

LowAlarm

HighAlarm

High HighTrip

ControllerSet Point

Fore Peak Ballast Tank

58-LT-125 0.1m 0.2m 31.5m(sounding)

32.5m

58-LZT-126 98%

Ballast Wing Tank No 1 Port

58-LT-101 0.1m 0.2m 30.61m 31.58m

58-LZT-102 98%

Ballast Wing Tank No 1 Starboard

58-LT-103 0.1m 0.2m 30.61m 31.58m

58-LZT-104 98%


58-LT-105 0.1m 0.2m 30.61m 31.58m

58-LZT-106 98%


58-LT-107 0.1m 0.2m 30.61m 31.58m

58-LZT-108 98%


58-LT-109 0.1m 0.2m 31.5m 32.5m

58-LZT-110 98%


58-LT-111 0.1m 0.2m 31.5m 32.5m

58-LZT-112 98%


58-LT-113 0.1m 0.2m 30.61m 31.58m

58-LZT-114 98%


58-LT-115 0.1m 0.2m 30.61m 31.58m

58-LZT-116 98%

Table 3.2 – Ballast Water Tank Alarm and Trip Settings







Low LowTrip

LowAlarm

HighAlarm

High HighTrip

ControllerSet Point


58-LT-117 0.1m 0.2m 30.61m 31.58m

58-LZT-118 98%


58-LT-119 0.1m 0.2m 30.61m 31.58m

58-LZT-120 98%


58-LT-121 0.1m 0.2m 30.61m 31.58m

58-LZT-122 98%


58-LT-123 0.1m 0.2m 30.61m 31.58m

58-LZT-124 98%

Aft Peak Water Ballast Tank

58-LT-127 0.1m 0.2m 22.64m 23.35m

58-LZT-128 98%

Table 3.2 – Ballast Water Tank Alarm and Trip Settings (cont’d)

3.3 Ballast System Controls

3.3.1 Primary Operation

The DCS Human Machine Interface (HMI) is the operator’s primary means ofoperation for the ballast pumps and valves. It is used to send speed controlcommands to the pumps and open/close signals to the valves, as well as monitoringthe level in the ballast tanks and main header lines.

The HMI also displays the current status of each pump and valve, ierunning/stopped or open/closed, alarms are reported in the CCR if feedback statusdoes not match the selected state of the pump or valve. Open and closed positionlimit switches are used on all valves except the proportional control valves, whichhave position transmitters to indicate 0 to 100%.

Each ballast pump has a dedicated hydraulic control valve, which dictates the speedof the pump and can be set from the CCR.

Under normal operation, main line isolation valves ZCV-141/142 will be closed sothat pumps P-5804A/B supply the port/aft/forward ballast tanks and pumpsP-5804C/D supply the starboard/aft/forward tanks, thus giving two separate ballastsystems one for each side of the vessel. However, if the ballast pipework is

damaged or maintenance is being carried out then these valves can be openedallowing the port and starboard tanks to be supplied from any of the pumps.






A degree of semi-automation is provided to assist the operator in some of theroutine tasks associated with ballasting, de-ballasting and flooding.

A sequence overlay is provided to allow selection of ballasting/de-ballastingoperation and to select the pump for this duty. The operator manually selects andopens the ballast tanks and routing valves from the CCR in advance of initiating thissequence. A sequence to aid the flooding (surge protection) of the header is alsoprovided.

Note: The application will not allow simultaneous selection of ballasting/de-ballasting.

There is no automatic control when loading or unloading the ballast tanks, however,information is provided by the loading computer regarding the ship’s current andpredicted hull stresses, trim and list.

To enable the ballast system to operate, the pump HPU and valve HPU must bestarted and available for operation. Once these have been confirmed, the operation

will depend on whether the tanks are being emptied (de-ballasting) or filled(ballasting).

For each wing ballast tank there are two isolation valves, the 20in main valve andthe 10in stripping valve.

Under normal operation the main valves will only be used. This main line will allowlowering of the level in the ballast tank to a minimum value.

The stripping valves are only used when the tank has to be emptied as much aspossible, ie during tank entry for inspection/maintenance. The smaller stripping linereduces the available flowrate from the tank and allows better internal drainingbefore the pump starts to draw air and thus loses suction.

The Fore Peak and Aft Peak Tanks have 20in main valves from the port andstarboard section of the ballast header and do not have the 10in stripping valves.

If the HPU is in local control, through 54-YS-214, all of the pump starts are ‘greyedout’ on the display.

The ballast pumps will not overpressure the discharge pipework, but excesspressure indicates a flow problem.

3.3.2 Operator Interface

The HMI located in the CCR is the primary operator interface.

The operator controls and indicators are as follows:

• Control from the DCS HMI

• Control and feedback setting of each pump hydraulic valve (to start/stop pump)

• Open and close commands for each on/off valve

• Position setting and indication for proportional control valves

• De-ballast button

• Ballast button

• Flooding button






• Pump sequence start button (1 for each pump)

• Manual override button (available at Operator Access Level 3 (OAL3) only)

Indications on the DCS HMI:

• Interlock status of each valve

• Interlock status of each pump

• Level indication for each ballast tank

• Liquid indication in ballast lines

• Valve position indication

• Pump running indication

• Suction strainer differential pressure

•

Suction and discharge pressure for each pump (discharge pressure is used aspump running indication)

3.3.3 Local Pump Control (at the Framo Control Unit)

Local operation of the ballast pumps is not envisaged. However, these pumps canbe operated from the Framo Control panel located in the Hydraulic Power Unit room,and the respective suction/discharge valves can be operated from the NakakitaSolenoid valve cabinet.

Start, Stop and Speed Control of the pumps can be performed by setting the pumpmotor hydraulic fluid flow control valve to a position between 0 to 300barg. If thepumps are operated from the Framo Control panel, they must be stopped before the

unit is switched to ‘local’ control.


Low LowTrip

LowAlarm

HighAlarm

High HighTrip

ControllerSet Point

Ballast Pump P-5804A

58-PT-102 0.5barg

58-PT-103 6.8barg

58-PT-101/102 1barg

Ballast Pump P-5804B

58-PT-105 0.5barg

58-PT-106 6.8barg

58-PT-104/105 1barg

Table 3.3 – Ballast Water Pump Alarm and Trip Settings







Low LowTrip

LowAlarm

HighAlarm

High HighTrip

ControllerSet Point

Ballast Pump P-5804C

58-PT-108 0.5barg

58-PT-109 6.8barg

58-PT-107/108 1barg

Ballast Pump P-5804D

58-PT-111 0.5barg

58-PT-112 6.8barg

58-PT-110/111 1barg

Table 3.3 – Ballast Water Pump Alarm and Trip Settings (cont’d)

3.4 De-ballasting

The de-ballasting operation can be activated either by pumping or gravity and inmany cases will be a combination of the two. The operator chooses to carry out asemi-automated operation by selecting the ‘De-ballasting’ button and then a‘Pump Sequence’ button. Manual operation is chosen by selecting the ‘ManualOverride’ button, which is only selectable at OAL3, opening the associated isolationvalves and starting the pump from the relevant overlay.

The tag numbers referred to in this description are for Ballast Pump P-5804A, referto Table 3.1 for the equivalent tag numbers for the other pumps.

To allow the pump to start, either the main or stripping valves for at least one tankassociated with that set of pumps and an overboard discharge valve must be opento remove the interlocks. If all the interlocks are not met, the letter ‘I’ will bedisplayed next to the pump on the display and the valve routing should be checkedby the operator. The pump cannot be started and the Start button on the overlay andPump Sequence button will be greyed out.

When the De-ballasting button is pressed and the Pump Sequence button isselected for the pump, the associated valves 58-ZCV-103/104/145, will be openedand the pump will be automatically started and run up to 5% (configurable).

The overboard discharge valve 58-ZCV-145 associated with the set of pumps will beconfirmed open and the sea chest valve 58-ZCV-101 will be confirmed closed by theapplication before starting the pump.

Once the pump is confirmed to be operating from the discharge line pressuretransmitter 58-PIT-103 greater than 0.5barg (configurable), the discharge valve58-ZCV-104 will be opened to 5% (configurable). The valve may be opened furtherfrom the valve overlay as required to meet the demand. The pump speed can bechanged from the pump overlay. The DCS sends an analogue output to the pumphydraulic valve located in the Cargo HPU control panel, feedback to the DCSconfirms that the pump speed has changed to the new setting through 58-SI-211.






When the pump output is set to 5% by 54-SY-211 and the required dischargepressure (58-PIT-103) is not achieved after a preset time delay (initially 5 seconds(configurable)), an alarm is raised ‘Pump Failed to Start’, the associated valves(58-ZCV-103/145/104) will be closed and the pump output will be driven to 0%.

This alarm will only be raised when the pump is started using the Pump Sequencebutton and not when the Manual Override is selected.

When the pumps are stopped from the display overlay, the starting sequenceis reversed, stopping the pumps and then closing the isolation valves58-ZCV-103/104/145.

If the sequence is manually overridden and the pump is stopped, the valves shallremain in the open position until they are selected closed by the operator. If thepump fails to stop, the valves will still be closed and an alarm raised.

The output of the pump is a combination of the hydraulic set point and the positionof the discharge valve (58-ZCV-104).

A discrepancy alarm is generated if the difference between the pump position outputand feedback (54-SY-211 and 54-SI-211) is greater than ±5% (configurable).This alarm is inhibited if the HPU is in local control.

Note: The hydraulic supply transmitter is ranged 0 to 253barg and the return isranged 0 to 300barg.

To allow a meaningful display, a 0 to 100% scale is used. To prevent unnecessarydiscrepancy alarms, the output display is 0 to 253 = 0 to 100% and the feedbackdisplay is 0 to 300 = 0 to 119%.

Normal operation of the pumps will be from the CCR, if the pumps are operatedfrom the local control panel located in the valve equipment room, the pumps must

first be stopped before the unit is switched to ‘Local’ control.

P-5804A P-5804B P-5804C P-5804D

58-ZCV-103 58-ZCV-106 58-ZCV-110 58-ZCV-113

54-SY-211 54-SY-212 54-SY-223 54-SY-224

54-SI-211 54-SI-212 54-SI-223 54-SI-224

58-PIT-103 58-PIT-106 58-PIT-109 58-PIT-112

58-ZCV-104 58-ZCV-107 58-ZCV-111 58-ZCV-114

58-ZCV-145 58-ZCV-145 58-ZCV-146 58-ZCV-146

58-ZCV-101 58-ZCV-101 58-ZCV-108 58-ZCV-108

58-ZCV-102 58-ZCV-105 58-ZCV-109 58-ZCV-112

Table 3.4 – Tag Nos for Ballast Pump Valves and Instrumentation






3.5 Ballasting

The ballasting operation can be activated either by pumping or gravity and in manycases will be a combination of the two. The operator will choose to carry out asemi-automated operation by selecting the Ballasting button and then a PumpSequence button.

Manual operation is chosen by selecting the Manual Override button (selectableonly at OAL3) then opening the associated isolation valves and starting the pumpfrom the relevant overlay.

The tag numbers referred to in this description are for Ballast Pump P-5804A.Refer to Table 3.1 for the equivalent tag numbers for the other pumps.

To allow the pump to start, either the main or stripping valve for at least one tankassociated with that set of pumps and the sea chest valve must also be open.

If all of the interlocks are not met, the letter ‘I’ will be displayed next to the pump on

the display and the valve routing checked by the operator. The pump cannot bestarted and the Start button on the display overlay and Pump Sequence button willbe ‘greyed out’.

When the Ballasting button is pressed and the Pump Sequence button is selectedfor a pump, the associated valves 58-ZCV-101/102/149 will be opened and thepump will be automatically started and run up to 5% (54-SY-211 will be set to 5%(configurable)).

The overboard discharge valve associated with the set of pumps will be confirmedclosed 58-ZCV-145 and the sea chest valve 58-ZCV-101 shall be confirmed open bythe logic before the pump is started.

Once it is confirmed that the pump is operating, from the discharge line pressuretransmitter 58-PIT-103 being greater than 0.5barg (configurable), the dischargevalve 58-ZCV-104 will be opened to 5% (configurable). The valve may be openedfurther from the valve overlay as required.

When the output is set to 5% (54-SY-211) and the discharge pressure 58-PIT-103does not reach the required pressure after a preset time of 5 seconds (configurable)an alarm is raised ‘Pump Failed to Start’, and the associated valves58-ZCV-101/102/149 will be closed and the pump will be stopped by driving theoutput to 0%. This alarm will only be raised when the pump is started using a PumpSequence button and not when the Manual Override is selected.

When the pumps are stopped from the display overlay, the starting sequence

is reversed, stopping the pumps and then closing the isolation valves58-ZCV-101/102/104/149. If the pump fails to stop, the valves will still be closed andan alarm raised.

If the sequence is manually overridden and the pump is stopped, the valves willremain in the open position until they are closed by the operator.

Once the pump has been started, the speed can be changed from the displayoverlay. The DCS sends a signal to the pump hydraulic valve located in the CargoHPU control panel and feedback is provided to the DCS by 58-SI-211 to confirm thatthe pump speed has moved to the new setting.






A discrepancy alarm is generated if the difference between the required and actualpump speed (54-SY-211 and 54-SI-211) is greater than ±5% (configurable).This alarm is inhibited if the HPU is in local control.

Normal operation of the pumps is from the DCS in the CCR, if the pumps are to beoperated from the local control panel located in the valve equipment room,the pumps must first be stopped before the unit is switched to ‘Local’ control.

3.6 Ballast Line Surge Protection

Both the port and starboard ballast lines are fitted with capacitance level probes58-LZT-133/34/35/36 near the forward and aft ends of the lines. These are toprovide an indication if the ballast line, in its vicinity of the sensor, is flooded.On sensing a non-flooded condition, eg pipe less than 90% full, an alarm in the DCSis raised on any of the sensors.

If any ballast pumps are running, identified by 58-PIT-103 output being greater than

0.5bar and the lines are not flooded, the stopping of the pumps and closing of thetank isolation valves 58-ZCV-115 to 140 and 143/144 is delayed for 10 seconds(configurable). The logic also prevents the opening of any further valves, withthe exception of 58-ZCV-101/108, 58-ZCV-102/112 (limited to 5% open),58-ZCV-103/113, 58-ZCV-147/148, 58-ZCV-141/142 and 58-ZCV-151, and alsoprevents pumps from starting until the condition is reset. This is to allow adequatestripping of any tank.

Note: When stripping a tank, some air is likely to be sucked into the main headerafter the water level falls below the bottom of the suction pipe.

Manual closing of the valves is not affected. This sequence and the associatedinterlocks operate irrespective of the selection of the ‘Manual Override’.

The ballast line is flooded by gravity filling through the following valves:

• 58-ZCV-101/108

• 58-ZCV-102/112 (limited to 5% open)

• 58-ZCV-103/113

• 58-ZCV-147/148

• 58-ZCV-141/142

• 58-ZCV-151

These valves are permitted to open either under Sequence control or Manually whilethe low level in the header exists.

To ‘re-flood’ the system, the Flooding button can be pressed which will automaticallyopen the following valves in this sequence when the pumps have been confirmedas stopped.

(1) 58-ZCV-151 – Ballast line vent.

(2) 58-ZCV-141/142 – Forward ring main isolation valves.

(3) 58-ZCV-147/148 – Middle ring main isolation valves.

(4) 58-ZCV-103/113 – Pump ‘A/D’ ballast lines suction.

(5) 58-ZCV-102/112 – Pump ‘A/D’ sea suction (proportional to 5%).

(6) 58-ZCV-101/108 – Sea chest isolation valves.






If the Flooding button is not used, all of the above mentioned valves will not beinterlocked and may be opened individually.

After the header has been flooded above 90%, the interlocks are removedautomatically and the ballast pumps can operate as normal, and the tank isolationvalves can be re-opened.

When any of the pumps are started, the ballast line vent isolation valve(58-ZCV-151) will automatically be closed after a configurable time set initiallyat 1 minute.


Low LowTrip

LowAlarm

HighAlarm

High HighTrip

ControllerSet Point

Port Water Ballast Header

58-LZT-133 40% 90%

58-LZT-134 30% 90%

Starboard Water Ballast Header

58-LZT-135 40% 90%

58-LZT-136 30% 90%

Table 3.5 – Ballast Water Header Alarm and Trip Settings

3.7 Manual Override

The Manual Override button is only accessible under OAL3. If the Manual Overridebutton is activated some of the start interlocks will be overridden, except when thelevel in the header detected by 58-LZT-133/34/35/36 is below 90%.

Note: Process interlocks or valve opening interlocks due to flooding will not beoverridden by this facility.

3.8 Header Isolation Valves

For normal operation, main line isolation valves 58-ZCV-141/142 will be closed sothat pumps P-5804A and B supply the port/aft/forward ballast tanks, and pumpsP-5804C and D supply the starboard/aft/forward tanks. Thus giving two separate

ballast systems, one for each side of the vessel.When the two separate systems are no longer required, the header isolation valves58-ZCV-141/42 can be opened so that any pump can operate on any tank.This condition is taken into account in the pump start interlocks.






3.9 Ballast Pump Discharge Valves

The operator can limit maximum output command for the discharge valve by usingsoftware pushbuttons.

When a proportional discharge valve is selected to Manual mode, the operator cangive ‘Fully Open’ or ‘Fully Close’ command and stop the output signals when therequired setting, as indicated by the position feedback, is achieved. Alternatively,the operator can give an ‘Open’ or ‘Close’ pulsed output command.

The open command will always be limited to the maximum value defined by theoperator from the mimic.

3.10 Hydraulic System Capacity

The HPU for the hull pumps is designed to operate five cargo and two ballast pumpsat maximum design head pressure. Any combination of pumps can be rundepending on the hydraulic demand on the HPU.

Ballasting operations normally only require two ballast pumps and an interlock isprovided to restrict the number of pumps in use to this number.

The HPU system supply pressure, which drives the ballast pumps, will depend onthe number of power packs running. It is the operator’s responsibility to ensure thereis a sufficient number of power packs running to meet the demand required forballasting/cargo operations.

An override button, accessible at OAL3, is provided on the pump overlay to allowthe simultaneous operation of more than two ballast pumps. The use of +2 pumpoperation will only be required in exceptional circumstances, such as a casualtysituation. An interlock has been inserted to prevent more than two pumps running in

normal operations.

3.11 Tank Cleaning/Transfer Main

Ballast pumps P-8804C/D can also be used for tank cleaning of the cargo storagetanks or transferring seawater to the cargo or slop tanks via the transfer main.Both operations use local manual valves and require the removal of spools. Thesespools must be placed when not in use. Water is pumped from the ballast pump via26-BUV-101 to the cargo transfer header and via 26-BUV-102 through the tankcleaning pump P-2604 and into the tank cleaning header. A dedicated button ‘TankCleaning’ is located on the ballast system functional buttons overlay. When selectedthe application will only allow pumps C or D to be used for tank cleaning. Pumps A

and B can still be used for ballasting in the other tanks.The operator will initiate a semi-automated operation by selecting the Tank Cleaningbutton and then a Pump Sequence button. Before the pump is started, the operatormust ensure that the relevant manual routing valves have been opened.

When the semi-automated operation is selected, the associated valves will beopened (58-ZCV-108/109) and the pump will be automatically started and run up to5% through 54-SY-223 (configurable).

Once confirmation that the pump is operating from the discharge line pressuretransmitter 58-PIT-109 being greater than 0.5barg (configurable) the discharge valve58-ZCV-111 will be opened (initially to 5% (configurable)) then the valve may beopened further from the valve overlay as required.






Once the pump has been started the pump speed can now be changed from theoverlay, the DCS will send a signal from 54-SY-223 via the serial link to the pumphydraulic valve, located in the Cargo HPU control panel. Feedback is provided to theDCS by 58-SI-223 to confirm that the pump has moved the desired amount.

A discrepancy alarm is generated if the difference between the pump position outputand feedback 54-SY-223 and 54-SI-223 is greater than ±5% (configurable).This alarm is inhibited if the HPU is in local control.

When the pump output is set to 5% and no discharge pressure is seen on58-PIT-111, after 5 seconds (configurable) an alarm is raised ‘Pump Failed to Start’,the associated valves 58-ZCV-108/109 will be closed and the pump output will bedriven to 0%. This alarm will only be raised when the pump is started using asequence button and not when the ‘Manual Override’ is selected.

If all the interlocks are not met the letter ‘I’ will be displayed next to the pump on thedisplay and the valve routing should be checked by the operator.

The pump cannot be started and the start button on the overlay and ‘PumpSequence’ button will be ‘greyed out’.

Manual operation is performed by selecting the ‘Manual Override’ button, which isonly selectable at OAL3, then opening the associated isolation valves and startingthe pump from the relevant display overlay. The tag numbers referred to in thissection are for Pump No P-5804-C. Refer to Table 3.1 for the equivalent tagnumbers for pump ‘D’.

When the pump is stopped from the overlay, the starting sequence is reversed,stopping the pumps first and then closing the isolation valves 58-ZCV-108/109. If thesequence is manually overridden and the pump is stopped, the valves remain in theopen position until closed by the operator.

Normal operation of the pumps is from the CCR, if the pumps are operated from thelocal control panel located in the valve equipment room, the pumps must first bestopped before the unit is switched to ‘local’ control.

3.12 Interlocks

Status of all Start-up Interlocks (STIL), Process Interlocks (PIL) and ShutdownInterlocks (SIL) are displayed on the ‘Interlocks’ pop-up, accessible from the pumpoverlay.

The overlay also provides facilities to override STILs and PILs at operator accessLevel 3 (OAL3). The interlock pop-up can be accessed from the overlay from each

pump/valve.

In Tables 3.6 to 3.12, where a message is shown in the ‘Tag No/Pop-up Message’column, this text is displayed as a message on the interlock pop-up.

Tables 3.6 to 3.9 list the interlocks and conditions for various control scenarios onthe Ballast System.






The pumps will be prevented from starting when the conditions listed below apply.

Tag No/Pop-up

MessageFunction Description

Two pumps * alreadyrunning

If two pumps are already running (reading on58-SI-103/06/09/12 greater than 0.5bar).

No pump HPUrunning

No power packs running (54-YS-201A to 209A).

Valve HPU Fault * If either (54-YA-001 or 54-YA-002) are in alarm or anyone of the common system alarms 54-YA-003 to 007 –valve HPU has failed.

All tanks isolated * When 58-ZCV-141 and 142 are open and none of the

isolation valves (58-ZCV-115 to 140 and 143/144)is open.

*Not valid if ‘Manual Override’ button is selected.

Table 3.6 – Common Start Interlocks for Ballast Pumps (P-5804A/B/C/D)



Check valve routing Pump A – If valves 58-ZCV-103 and 58-ZCV-102 are

both closed or both open, or 58-ZCV-104 is open(58-ZT-104 ≠ 0%).

Check valve routing Pump B – If valves 58-ZCV-106 and 58-ZCV-105 areboth closed or both open, or 58-ZCV-107 is open(58-ZT-107 ≠ 0%).

Check valve routing * Pumps A and B – When 58-ZCV-141 is closed and58-ZCV-147 is open and all of the valves58-ZCV-115/116/119/120/123/124/127/128/131/132/135/136/139/143 are closed.

Check valve routing * Pumps A and B – When 58-ZCV-141 and 58-ZCV-147are closed and all of the following valves58-ZCV-115/116/119/120/123/124 are closed.

Check valve routing * Pumps A and B – 58-ZCV-145 and 58-ZCV-149are open.

* Not valid if ‘Manual Override’ button is selected.

Table 3.7 – Start-up Interlocks – Ballasting or De-ballasting (P-5804A and B)








Check valve routing Pump C – If valves 58-ZCV-110 and 58-ZCV109 areboth closed or both open, or 58-ZCV-111 is open(58-ZT-111 ≠ 0%).

Check valve routing Pump D – If valves 58-ZCV-113 and 58-ZCV112 areboth closed or both open, or 58-ZCV-114 is open(58-ZT-114 ≠ 0%).

Check valve routing * Pumps C and D – When 58-ZCV-142 is closed and58-ZCV-142 is open, and all of the following valves58-ZCV-117/118/121/122/125/126/129/130/133/135/137/138/140/144 are closed.

Check valve routing * Pumps C and D – When 58-ZCV-148 and 58-ZCV-142are closed, and all of the following valves58-ZCV-117/118/121/122/125/126 are closed.

Check valve routing * Pumps C and D – 58-ZCV-150 and 58-ZCV-146are open.


Table 3.8 – Start-up Interlocks – Ballasting or De-ballasting (P-5804C and D)

Tag No/Pop-upMessage Function Description

Check valve routing Pump C – If valves 58-ZCV-110 and 58-ZCV-109 areboth closed or both open, or 58-ZCV-111 is open(58-ZT-111 ≠ 0%).

Check valve routing Pump D – If valves 58-ZCV-113 and 58-ZCV-112 areboth closed or both open, or 58-ZCV-114 is open(58-ZT-114 ≠ 0%).

Check valve routing * Pumps C and D – When 58-ZCV-146 is open.


Table 3.9 – Start-up Interlocks – Tank Cleaning (P-5804C and D)






3.13 Logic Conditions

The following logic is applied to pump control through the control facilities.



P-5804APump trip 54-YZC-103# immediately stops pump(set 54-SY-211 – output = 0%) and prevents pumpfrom starting.

P-5804BPump trip 54-YZC-103# immediately stops pump(set 54-SY-212 – output = 0%) and prevents pumpfrom starting.

P-5804C

Pump trip 54-YZC-103# immediately stops pump

(set 54-SY-223 – output = 0%) and prevents pumpfrom starting.

P-5804DPump trip 54-YZC-103# immediately stops pump(set 54-SY-224 – output = 0%) and prevents pumpfrom starting.

# 54-YZC-103 is the trip signal from the SSDS to the cargo control system to driveall ballast pumps to 0%. The HPU (hydraulic supply) will still be available for otherend users.

Table 3.10 – Process Shutdown Logic



P-5804A/B C/DPump outputs (54-SY-211/212/223/224) will be held at0% until 58-LZT-133/134/135/136 have returned belowtrip state.

58-ZCV-102/112Valves can only be opened 5% until 58-LZT-133 to 136have returned below trip state and been reset.

Table 3.11 – Header Flooding Logic



P-5804 A/BC/D All four ballast pumps can be run at the same time, if theManual Override from the overlay is selected.

P-5804 A/B/C/D

When not in Manual Override Mode – Interlock to stopsimultaneous ballasting and de-ballasting operation,ie the ballast button shall be greyed out whende-ballasting is taking place.

Table 3.12 – Abnormal Conditions Logic






4.0 SAFEGUARDING

Protection against potential overfilling of the Ballast Water Tanks is provided by theHigh Level alarm signal from the Metritape system, and the High High alarm signalfrom the capacitive probes. The set points for all of the Ballast Water Tank HighLevel Alarms is 95% and the High High alarm signal is provided at 98% of thetank capacity.

The activation of the Level Alarm is annunciated in the DCS.

If hydrocarbons should leak into a ballast tank, inert gas can be provided to inert thetanks from the clean inert gas header through either of the ballast/de-ballast lines orthrough flexible connections to the tank lid.






6P T-5801M

Z CV -1 35 Z CV -1 36

ZCV-119 ZCV-120

P-5804-A

P-5804-B

ZCV-104

PIT-103

PIT-102 ZCV-103

ZCV-102

ZCV-107 PIT-106

PIT-105

ZCV-105

ZCV-101

Overboard

ZCV-145 Sea

Chest

ZCV-106

ZCV-149

P-5804-C

P-5804-D

ZCV-111

PIT-109

ZCV-110

ZCV-109

ZCV-114PIT-112

ZCV-112 ZCV-108

Overboard

ZCV-146 Sea

Chest

ZCV-113

ZCV-150

ZCV-148

ZCV-147

ZCV-144

ZCV-143

LZT-136

5P T-5801K 4P T-5801H 3P T-5801F 2P T-5801D 1

Aft Tan k

T-5801P

6S T-5801N 5S T-5801L 4S T-5801J 3S T-5801G 2S T-5801E 1

Port Draft

PIT-101

PIT-104

PIT-108 PIT-107

PIT-111 PIT-110

P

P

P

P

P P

ZCV-132 ZCV-131 ZCV-127 ZCV-128 ZCV-123 ZCV-124 ZCV-120 ZCV-119 ZCV

Z CV -1 37 Z CV -1 38 Z CV -1 33 Z CV -1 34 ZCV-129 ZCV-130 ZCV-125 ZCV-126 ZCV-121 ZCV-122 ZC

58-LIT-121

xxx%

58-LZT-122

HH

58-LIT-117

xxx%

58-LZT-118

HH

58-LIT-113

xxx%

58-LZT-114

HH

58-LIT-109

xxx%

58-LZT-110

HH

58-LIT-105

xxx%

58-LZT-106

HH

58-LIT

xxx%

58-LIT-123

xxx%

58-LZT-124

HH

58-LIT-119

xxx%

58-LZT-120

HH

58-LIT-115

xxx%

58-LZT-116

HH

58-LIT-111

xxx%

58-LZT-112

HH

58-LIT-107

xxx%

58-LZT-108

HH

58-LIT

xxx

58-LIT-130

xxx%

58-LIT-127

xxx%

58-LZT-128

HHFwd

58-L

x

Aft Draf t

58-LIT-132

xxx%

xxx%

LZT-134

xxx%

xxx bar

PDI-101

xxx barg

xxx barg xxx bar

PDI-104

xxx barg

xxx barg

xxx %

xxx %

SIC-212

xxx %

xxx %

xxx bar

PDI-107

xxx bar

PDI-110

xxx %

xxx %

xxx %

xxx %

xxx %

xxx %

x xx ba rg x xx ba rg

x xx ba rg x xx ba rg

xxx barg xxx barg

xxx barg xxx barg

Starboard

Draft

58-LIT-131

xxx%

SIC-211

SIC-223

SIC-224

COW

H_COW_SD


OPRM-2003-0304 Page 24 of 24





Section 4Detailed Description – Crude Oil Washing

Table of Contents

1.0 INTRODUCTION.............................................................................................................2


2.1 COW and Tank Cleaning Header........................................................................3

2.2 Tank Washing Machines.....................................................................................3


3.1 General................................................................................................................5

3.2 Crude Oil Washing .............................................................................................. 5

3.3 Water Washing Open/Closed Cycle.................................................................... 6

TABLES

Table 4.1 – Crude Oil Washing Machine Locations ................................................................. 4

Part 1 Section 4 Detailed Description – Crude Oil Washing





1.0 INTRODUCTION

Tank cleaning should only be undertaken when there is a specific and justifiablereason to do so. In general, tank cleaning is used for the removal of residues,wax and clingage from all cargo tank and slop tank surfaces that could result inunsafe conditions for tank entry or unacceptable build-up of residues.

The tank washing methods available are as follows:

Crude Oil Washing (COW)

The cargo and slop tanks are equipped with fixed tank cleaning machines served byfixed piping which can use crude oil as a washing medium. By this method, some ofthe crude oil from the cargo oil pumps discharge is directed to the fixed tankcleaning machines. This is the normal method used to clean the Cargo Tanks.

On a standard tanker COW is only performed during Cargo Offloading Operations,whereas on an FPSO it is normal to Crude Oil Wash between offtakes. Doing this

avoids reducing the discharge rate, thus reducing exposure to demurrage claims,and allows flexibility in the timing of the operation, which will be done during daylighthours where possible.

Seawater Washing

This process is carried out prior to tank entry and is used to thoroughly clean allinternal surfaces of the Cargo Tanks, using hot or cold water, before gas-freeingprocedures commence.

The use of cold seawater (up to 35°C) has been found to be adequate for mostin-service tank cleaning and it is preferred to hot water. It is possible that when avery high standard of cleanliness is needed (hot work repairs) it may be necessaryto use hot water. When to use hot water will be identified from experience.

When washing with hot water it is essential that the temperature is well above themelting point of the wax in the cargo residues. If residues are first liquidised in thisway but then allowed to cool they will solidify into a hard and rigid substance whichis very difficult to remove. For this reason the temperature of hot wash water should

be at least 85°C while temperatures between 35°C and 65°C must be scrupulouslyavoided as washing in this temperature range causes an emulsion. As no tankcleaning heater is fitted and the slop tank coating temperature is limited to about

70°C for short periods, hot water washing will be done only under exceptionalcircumstances.


• BON-SHI-008-P-00002-018 Tank Cleaning and Nitrogen Headers

• BON-SHI-008-P-00002-019 Storage Compartment 1 and 2 Tank Cleaningand Utilities

• BON-SHI-008-P-00002-020 Storage Compartment 3 Tank Cleaning and Utilities











2.1 COW and Tank Cleaning Header

Refer to P&ID BON-SHI-000002-018-00. A COW/Tank Cleaning (COW/TC) Header is provided on the Upper Deck of BongaFPSO and this facility is used for both Crude Oil Washing and Seawater Washing.

Crude oil for washing purposes is directed to the COW/TC Header throughcrossover isolation valves 26-ZCV-113/114 at the forward end and 26-ZCV-061/128at the aft end of the Discharge Header.

The manual in-line filter isolation valves, 26-BUV-074 and 26-BUV-075 (aft) and26-BUV-076 and 26-BUV-077 (forward), are fitted either side of the aft and forwardin-line filters, S-2601A/B. An isolation valve, 26-BUV-070, can be used to isolate theforward and aft sections of the COW/TC Header.

The submerged Cargo Oil Pumps (refer to POPM Volume 5 Oil Metering and ExportSystem (OPRM-2003-0305)) are operated as necessary to direct crude oil to theDischarge Header. Once the crossover valves on the selected supply line, forwardor aft, from the Discharge Header to the COW/TC Header is opened, crude oil isavailable from the header for tank cleaning.

In-line filters S-2601A/B are located in both crude oil supply lines to remove anyparticulate matter. Each is provided with a differential pressure transmitter26-PDIT-042/043. The filters can be cleaned when the Crude Oil Washing System isshut down and the supply line isolated.

A spur with an isolation valve connects each tank cleaning machine, programmableand submerged, to the COW/TC Header to permit the crude oil or water for washing

to be directed to the tank cleaning machines in the Cargo Oil Tank to be cleaned.The spurs to the individual tank cleaning machines are fitted with coarse in-linestrainers.

The COW/TC Header supplies the fixed Tank Cleaning Machines provided in theCargo Oil Tanks with crude oil at a minimum pressure of 8barg.

2.2 Tank Washing Machines

Refer to P&ID BON-SHI008-P-000002-024-00 Storage Compartment 7 TankCleaning and Utilities and BON/1FA1108/GUNCLEAN/000001 Fixed Tank CleaningMachine.

Single nozzle, programmable, fixed Tank Cleaning Machines mounted on deck andin the larger centre tanks twin-nozzle submerged non-programmable Tank CleaningMachines, located in the tank bottom, are provided for all Cargo Oil Tanks incompliance with MARPOL regulations. These facilities are suitable for Crude OilWashing and Seawater Washing. The Slops Tanks are also provided with fixed,deck-mounted Tank Cleaning Machines and submerged Tank Cleaning Machines.

A complete listing of the Tank Cleaning Machines and their locations is provided inTable 4.1.






Tank NoDeck-mounted

Gunclean 270FTSubmerged TZ-65

COT No 1 Port/Starboard 3 off –

COT No 1 Centre 3 off 2 off









Port Slops Tank 2 off 1 off

Starboard Slops Tank 2 off 1 off

Table 4.1 – Crude Oil Washing Machine Locations

The deck-mounted, fixed tank cleaning machines are Toftejorg Gunclean 270FT

units fitted with 30mm nozzles and integral controllers. The units are 3.5m and4.0m long and can be operated with a supply pressure in the range of7 to 12barg.

The nozzle angle, range and time duration for any set washing programme can beselected by choosing the suitable programme located on top of the turbine housing.

The programme selector for the Toftejorg machines is mounted on the cover platefitted to the unit. This allows the controller settings and nozzle angle to be checkedat any stage during the tank washing sequence.

The nozzle is designed to operate with a slow vertical movement, whilesimultaneously rotating about its vertical axis. This produces a helical spraying effectpattern inside the tank that ensures that the interior walls are thoroughly cleaned.

The time taken to complete one full tank washing cycle is approximately 60 minuteswith nozzle revolution set between 1.5 to 2.5rpm. A full cycle consists of onecomplete nozzle pass through the designed vertical arc of rotation from 0° to 120°;these actions are summarised in the following table.






Cycles/Rotation/Time Units of Measurement

One Full Cycle 120° – 0° – 120° – 0°

Time (T) Approximately 60 minutes

Horizontal rotations (rpm) 1.5rpm

One Bottom Cycle 30° – 0° – 30° – 0°

Time (T) Approximately 30 minutes

Horizontal rotations (rpm) 1.5rpm

The submerged Tank Cleaning Machines are Toftejorg TZ-65 units. These cleaningunits are non-programmable and are fitted with twin nozzles. The units are situated

3m above the tank bottom. The asymmetrically opposed nozzles are driven by anintegral turbine to achieve stable speed control.

Once the manual isolation valve on the Tank Wash Line is opened, the nozzles

rotate around 360° at a fixed speed to produce the maximum wash effect inthe tank.


3.1 General

During the normal operation of Bonga FPSO, oil sludge, wax and sediment will build

up in cargo oil tanks. Thus all cargo tanks and the slop tanks require to be washedperiodically. There are two mediums for washing these tanks, crude oil and water.The most frequently employed method is crude oil washing. Water washing of thetanks is usually only carried out prior to tank entry for inspection purposes.

Crude Oil washing and Tank Cleaning are manual operations performed usingmanual valves and local controls at each tank washing machine. The followinginformation describes the manual processes.

3.2 Crude Oil Washing

Cleaning of the cargo tanks will normally be undertaken between cargo discharges.

One or more cargo pumps require to be used to maintain the COW/TC Header atleast at 8bar.

The valves connecting the discharge header to the Tank Cleaning Header mustbe opened. This can either be hydraulically-operated valves 26-ZCV-061 and26-ZCV-128 along with manual valves 26-BUV-074 and 26-BUV-075,or hydraulically operated valves 26-ZCV-113 and 26-ZCV-114 along with manualvalves 26-BUV-076 and 26-BUV-077.

Manual valve 26-BUV-070 is situated in the middle of the Tank Cleaning Headerand is to allow the header to be split for maintenance or if damage has occurred.








The distribution to an individual set of tanks is through a series of manual valves.The isolation valve to the set of cross tanks must be opened and then the individualtank cleaning machine valves opened. The oil used to wash the tank is returned tothe transfer header by the individual cargo pump in each tank.

When carrying out crude oil washing a large volume of vapour is produced and thecargo tank pressure must be monitored closely.

3.3 Water Washing Open/Closed Cycle

Water washing of the cargo tanks is normally carried out prior to entry into the tankfor routine inspection or maintenance. This allows any residual oil or sludge to beremoved to allow safe entry. This water washing can be carried out by either hot orcold water.

3.3.1 Hot Washing

Seawater is placed in the clean slop tank via the ballast pump, transfer headerand the tank cleaning return line. This water is heated in the slop tank by theinstalled heating coils. These heating coils use waste heat from the topside.

It will take approximately 24 hours to raise the temperature to 65°C.The temperature must not be below this for hot washing.

Note: The temperature must no exceed 65°C during hot washing to preventdamage to the tank coating.

This hot water is delivered by the clean slop pump to the COW/Tank CleaningHeader via manual valves 26-BUV-042, 26-BUV-049 and 26-BUV-070 as required,and 26-BUV-074 and 26-BUV-078. The hot water will be distributed to the individualtank cleaning machines as mentioned above.

The water used to clean the tank is returned by the tank cargo pump to the transferheader and hence to the dirty slop tank.

3.3.2 Cold Wash

Open Cycle

With a Ballast Pump P-5804D/C in operation, water is supplied to the Tank CleaningBooster Pump P-2604. This booster pump increases the seawater pressure up to10barg before discharging into the tank cleaning header via manual valve26-BUV-066. Distribution to the individual machines and drainage of the tanks isas above.

Closed Cycle

As for hot wash, but without the use of the heating coils.





Section 5Detailed Description – Slops System

Table of Contents

1.0 INTRODUCTION.............................................................................................................2


2.1 Slop Tanks...........................................................................................................2

2.2 Slop Pumps ......................................................................................................... 4

2.3 Dirty Slop Tank Oil Skim Pump P-2603...............................................................5

2.4 Clean Slop Tank Clean Water Pump...................................................................6

2.5 Overboard Discharge Monitoring System............................................................6


3.1 Slop Tank Level Gauging .................................................................................... 8

3.2 Pump Controls and Interlocks ............................................................................. 9

3.3

Oil Discharge Monitoring System ...................................................................... 10

4.0 SAFEGUARDING.........................................................................................................12

TABLES

Table 5.1 – Slops Tank Alarm and Trip Settings......................................................................8

Table 5.2 – Start Interlocks (STIL) – Slop Tank Pumps .........................................................10

Table 5.3 – Process Interlocks – Slop Tank Pumps...............................................................10

FIGURES

Figure 5.1 – Graphical Interface – Slops................................................................................13

Part 1 Section 5 Detailed Description – Slops System





1.0 INTRODUCTION

The slop tanks are designed to treat mixtures of water and entrained oil from crudeoil processing, cargo handling, cargo tank washings, open and closed drains andbilge systems.



• BON-SHI-008-P-00002-009 Storage Compartment 1 (Dirty Slop Tank)

• BON-SHI-008-P-00002-010 Storage Compartment 2 (Clean Slop Tank)

• BON-SHI-008-P-00002-033 Cargo Heating System

• BON-SHI-008-P-00002-007 Position of Tank Gauging and HandDipping System


2.1 Slop Tanks

Equipment Details

Tag Number: T-2603, T-2602

Capacity: 5129.3m3 each

Maximum OperatingPressure: 1600mm WG (1.6barg)

Minimum Operating

Pressure: -200mm WG (-0.2barg)

Maximum OperatingTemperature: 66oC

Refer to Figure 5.1 or P&IDs BON-SHI-008-P-00002-009 Storage Compartment 1(Dirty Slop Tank) and BON-SHI-008-P-00002-010 Storage Compartment 2(Clean Slop Tank).


The slop tanks are rectangular compartments built into the hull of Bonga FPSO andare located on the port and starboard sides of the vessel aft of the cargo tanks.Each tank has a storage capacity of 5129.3m3.

Both tanks are fitted with heating coils that can be used to assist oil/water separationand to heat clean seawater prior to water-washing of cargo tanks. When usingthe heating coils, it is important to check the heating medium return to theWHRU for oil contamination by sampling from the return line bleed valves57-GBV-009/011/013/022/024/026.

The two slop tanks are designated as Dirty (port) and Clean (starboard). Duringnormal operations the port slop tank receives the mixtures to allow time for settlingout before the water is transferred to the starboard clean tank.






When time has been allowed for settling, separated water near the bottom of theport slop tank is allowed to flow through the lower decanting line driven by thehydrostatic head into the adjoining starboard clean slop tank. The decanting line isdirected upwards in the clean slop tank in order to direct any entrained oil towards

the surface.Oil is removed from the upper part of the dirty slops tank by a Dirty Slops Tank OilSkim Pump P-2603, which delivers the wet oil to a selected cargo tank, normally thereception tank 3C, via the transfer header.

There are also facilities to isolate the flow to the transfer header and pump to theFlare Scrubber V-4640 for disposal to the LP Separator V-2340A via the FlareScrubber Pumps P-4640A/B/C.

Level Controller 46-LC-301 controls the level in the flare scrubber. As the level rises,the lead Flare Scrubber Pump is started at 550mm and pump discharge valve46-PDCV-320 is enabled. If the liquid level continues to rise to 700mm, the standbypump is started.

If the level continues to rise, Level Control Valve 46-LCV-301 is opened to dumpliquid to the dirty slop tank or Reception Tank 3C at a level of 1100mm.

When the liquid level falls to its low setting of 450mm, the pumps are stopped and46-LCV-301 is closed.

At a level of 300mm, Shutdown Valve 46-SDV-310 upstream of 46-LCV-301 isclosed, preventing gas blowby to the slop oil tank.

The port slop tank should be more than 50% full to give the differential headrequired. Remote Operated Valves 26-ZVC-110 (Proportional) and 26-ZVC-111 canbe opened to allow flow into the starboard slop tank. Subject to operationalrequirements, the proportional valve should be used to make the flow between thetwo tanks as slow as practical.

After confirmation by sampling that the oil-in-water content of the starboard slop tankis below 29ppm, water can be discharged overboard.

The last few metres contain higher oil contamination levels so pumping should bestopped before stripping occurs. The overboard discharge from the starboard sloptank must be visually monitored whilst the Clean Water Overboard Pump is running.

If a significant amount of oil collects on the water surface of the starboard slop tank,it can be skimmed from the surface by filling the tank with water. When the level isabove the upper oil skim pipe inlet approximately 70% height from the bottom of thetank, the top level can be run off, back into the port tank by hydrostatic head

via Remote Operated Valves 26-ZVC-109 (proportional) and 26-ZVC-108.The proportional valve should be used to slow the flow to the port slop tank.

To prevent the possibility of a hazardous atmosphere forming in the tank, inert gasis used to fill the tank ullage space at a slight positive pressure. Inert gas normallyenters or is released from the slop tanks via a 250mm line from the dirty inert gasheaders. The dirty and clean inert gas headers connect to the tank via a three-wayvalve that ensures one inert gas header is always aligned to the tanks.

Tank pressure is controlled by venting inert gas through the dirty Inert Gas Headerpressure control system. For details of the Inert Gas System refer to POPMVolume 19 Inert Gas System (OPRM-2003-0319).

Each slop tank is provided with two fixed Tank Cleaning Machines fitted to the roofof the tank and one submerged in the tank to enable the tank to be cleaned.






To aid separation of the oil and water and in breaking emulsions, heating coils areinstalled in the bottom of the slop tanks. The coils have three individual passes in

each tank that are supplied with heating medium at 204°C and at a pressure of16barg from the topside facilities.

The topsides overflow is normally routed to the primary reception tank COT 3Cthrough Locked Open Manual Isolation Valve 26-BUV-048. There are also facilitiesto route the topside overflow to the Dirty Slop Tank via normally Locked ClosedManual Isolation Valve 26-BUV-047. If the configuration is required, 26-BUV-047must be opened and Locked Open Manual Isolation Valve 26-BUV-048 shouldbe closed.

The topsides drain passes to the dirty slops tank through Locked Open ManualIsolation Valve 26-BUV-045. There is also a facility to route the topside drain to theprimary reception tank COT 3C via normally Locked Closed Manual Isolation Valve26-BUV-046. If this configuration is required, 26-BUV-045 must be opened andLocked Open Manual Isolation Valve 26-BUV-046 should be closed.

2.2 Slop Pumps

Equipment Details

Tag Number: P-2605A and P-2605B

Type: SD200

Capacity: 400m3/hr

Discharge Pressure: 12 to 13barg

Head/Specific Gravity: 150m at rated speed/0.89

Viscosity: 8.2cstMotor: Hydraulic high-pressure motor

Tank Depth/Pump Length: Approximately 32/33.32m

Refer to Figure 5.1 or P&IDs BON-SHI-008-P-00002-009 Storage Compartment 1(Dirty Slop Tank), BON-SHI-008-P-00002-010 Storage Compartment 2 (Clean SlopTank) and BON/1JA0980/FRANK/000001 Cargo Oil Pump.


Slop pumps P-2605A/B are fitted taking suction from the bottom of the clean anddirty slop tanks, which can discharge the contents of the tank into either the transferor COW/TC headers. Although they both share a common discharge line,two spectacle pieces are provided which provide positive isolation to allow thestarboard slop pump, P-2605A, to be utilised as a back-up clean water pump.It is essential that one of these spectacle pieces is always closed in order tomaintain the cleanliness of the clean water overboard line. The pumps aresubmersible, single-stage, centrifugal pumps driven by a hydraulic motor,close-coupled to the pump. Each pump has a rated capacity of 400m3/hr.

The submerged slop pumps are supported and positioned in the tank by means of adeck flange resting on the deck trunk and supported by an intermediate support ringand a bottom support. The pump impeller is driven by a built-in high-pressurehydraulic motor via a short shaft. The shaft is supported by bearings, which are

lubricated and cooled by the hydraulic oil drain from the submerged pump motor.






The pump pipe stack consists of two separate lines, the discharge line and hydraulicoil line. The hydraulic oil line is made up of three concentric pipes. The inner pipetransfers the high-pressure hydraulic oil which drives the pump motor and thelow-pressure hydraulic oil returning from the pump motor passes through an annulus

formed between a second concentric pipe and the supply line. A second annulusbetween the return pipe and a third concentric pipe acts as a cofferdam between thecargo on the outside and hydraulic pipes on the inside.

This cofferdam space is filled with hydraulic fluid and the hydrostatic head ismaintained by a Header Tank fitted with a gauge glass, which allows the level tobe monitored.

The slop pumps are fitted with the same stripping arrangement as the cargo pumps.

Shaft seals are arranged to prevent any leakages between the cargo and cofferdamand between the cofferdam and hydraulic oil returns from the pump motor. Any leakages getting past the shaft seals or any other seal will migrate to the

cofferdam, which always operates at the lowest pressure.The pump motors are powered by high-pressure hydraulic oil supplied at amaximum pressure of 260barg by the Framo Hydraulic System. The Slop Pumpcapacity is controlled by adjusting the hydraulic supply pressure to the pump motor.Full details on the Framo Hydraulic System are provided in POPM Volume 26 DeckHydraulic Power Systems (OPRM-2003-0326).

The Slops Pumps are operated from the Framo Control Panel or remotely from theDCS System.

2.3 Dirty Slop Tank Oil Skim Pump P-2603

Equipment Details

Tag Number: P-2603

Capacity: 100m3/h

Discharge Pressure: 15barg

Speed: 4458rpm



Skimming Pump P-2603 is a submersible, single-stage, centrifugal pump located inthe port Slop Tank driven by a hydraulic motor. The pump has a discharge flowcapacity of 100m3/hr and discharges directly to the transfer header.

When the oil/water interface in the Port Slop Tank is at or below 70% of the tanklevel, oil floating at the top can be removed by the Skimming Pump. While this isbeing done, careful monitoring of the operation is required to ensure that oil and notwater is pumped into the cargo tanks. The pump will be stopped and inhibited fromstarting if either the interface level 26-LZT-036 is above the pump suction or the tanklevel 26-LIT-032 reading is below the pump suction.

The technical description and operation of the pump is as described for theSlop Pumps.






2.4 Clean Slop Tank Clean Water Pump

Equipment Details

Tag Number: P-2602

Capacity: 240m3/h

Discharge Pressure: 15barg

Speed: 2550rpm



Clean Slop Tank Clean Water Overboard Pump (P-2602) is a submersible,single-stage, centrifugal pump located in the bottom of the starboard Slop Tank

driven by a hydraulic motor. The pump has a discharge flow capacity of 240m3/hr.

The pump is used to deliver water from the clean slop tank into the Slop Pumpdischarge header for disposal overboard.

The pump discharges into the slop tank common discharge header, however aspading arrangement keeps the overboard section of the header positively isolatedfrom the rest of the system. The same spading arrangement can allow the cleanslop tank pump to pump overboard in the event of failure of the clean water pump.

UNDER NO CIRCUMSTANCES MUST THE TWO SPECTACLE BLINDS INTHIS SPADING ARRANGEMENT BE SIMULTANEOUSLY IN THE OPEN

POSITION OTHERWISE THERE IS A SERIOUS RISK OF CONTAMINATINGTHE OVERBOARD DISCHARGE PIPEWORK.

The technical description and operation of the pump is as described for theSlop Pumps.

2.5 Overboard Discharge Monitoring System

Refer to BON/1SA1043/SEIL/000001 Oil Discharge Monitoring System.

The Overboard Discharge Monitoring System (ODMS) equipment is distributedbetween hazardous and safe areas according to its certification.

The unit comprises the following major items:

• Hydraulic Panel

• Sample Pump

• Measuring Vessel

• Oil-in-water Analyser

• Remote Control Panel

The monitoring system is controlled from the local and remote control panels andmust be started and stopped whenever clean water is being discharged from theslop tanks.






The sample is drawn through a sample probe on the overboard discharge line andflows through a strainer to the hydraulic panel. In addition to the sample probe onthe line there is a flow measurement device, which feeds a signal to the remotecontrol panel (calculator) in the control room, to be used in computing the actual

quantity of oil passing through the overboard line.

In normal operation, the sample flows to the suction of the sample pump where thepressure is increased to 5barg to deliver the sample to the measuring vessel.

Routing of the sample to the pump is performed by the pneumatic valves in thehydraulic panel which are controlled by air signals from the Oleometer cabinet.

There are four pneumatic valves in the cabinet to enable the following functions tobe performed:

• Test Running

• Backflushing

• Calibration

• Monitoring

A clean water supply is provided at the hydraulic panel to flush the measuring vesseland sample line during backflushing and for use as calibration media.

The pneumatic valves are used to switch between the sample and water supply andto direct the water from the measuring vessel outlet. Control of the valves is bysolenoid valves in the Oleometer cabinet, which switch the air signals on commandsfrom the remote control panel. LEDs inside the cabinet indicate when solenoids areenergised.

The sample pump is a mono pump driven by 415V electric motor with a power ratingof 1.5kW. The pump discharges at a maximum pressure of 5barg at a flowrate of750 litres/hr.

The measuring vessel is an ODME S663 MKIII photometer manufactured by Seres.This part of the analyser is bulkhead-mounted and has no electrical components soit can be located in a hazardous area. The electrical components are located in theOleometer cabinet in a safe area on the opposite side of the bulkhead.

The sample flows upwards through a glass tube where it is exposed to light from a

lamp. There are two detector cells, one offset by 30° and one set 90° from the axisof the light source. Any oil in the water flowing through the tube will fluoresce and be

detected by the detector set at 90°. The amount of fluorescence produced is

dependent upon the amount of oil in the sample.The detector set at 30° to the light path is used to measure the turbidity of the water.

To monitor the intensity of the light source there is a compensating cell locateddiametrically opposite the light source, which adjusts the power to the light source.

The light source and detector cells are actually located in the Oleometer cabinet andconnect to the measuring vessel through optical fibre connectors passing throughthe bulkhead.

As the sample will contain some oil, this may collect on the inside of the glass tubeand affect the operation of the instrument. The measuring vessel is equipped with apneumatically-operated cleaning device, which drives a wiper up and down the

inside of the glass tube.







3.1 Slop Tank Level Gauging

Slop tanks are provided with a Saab Tank Radar level gauge system. This is usedas the primary level sensing system.

The system installed on each slop tank consists of a radar level transmitter26-LIT-032/034, tank pressure transmitter 26-PT-016/017, and three sets oftemperature sensors for each tank 26-TT-046/47/48 and 26-TT-049/50/051.The temperature in each tank is measured at three levels; 15%, 50% and 85%.These signals are interfaced to DCS via a serial link.

The Saab system provides high and low level, high and low pressure and highTemperature Alarms on DCS.

In addition to the Saab system, a Metritape Vanguard back-up level transmitter26-LZT-031/033 is installed which provides high-high level trip signals. The trip

signal closes all inlet valves to the tank and shuts down the cargo pumping systemwhen the tank level exceeds 98% of capacity (volume). This system is totallyindependent of the radar gauges and is connected directly to the SSDS.

The two slop tanks are also provided with Halla Oil/Water Interface LevelTransmitters, 26-LZT-035 and 036. These provide interface level indication and alow-level alarm on the DCS to an accuracy of +/-0.5%.


Low LowTrip

LowAlarm

HighAlarm

High HighTrip

ControllerSet Point

Dirty Slop Tank (Port)

26-LIT-032 32.322m 1.701m

26-PT-016 40mbar 120mbar

26-LZT-031 0.68m

26-LZT-036 33.002m

Clean Slop Tank (Starboard)

26-LIT-034 32.12m 1.69m

26-PT-017 40mbar 120mbar

26-LZT-033 0.676m

26-LZT-035 32.796m

Note: These settings are fed to the DCS and the levels are measured as ullage inmetres.

Table 5.1 – Slops Tank Alarm and Trip Settings






The two slop tanks are each equipped with three Temperature Transmitters,as follows:

• Clean Slop Tank T-2602 – 26-TT-049/050/051

•Clean Slop Tank T-2603 – 26-TT-046/047/048

These provide temperature indication and high temperature alarms on the DCS at15%, 50% and 85% tank levels respectively.

3.2 Pump Controls and Interlocks

Refer to Figure 5.1 and P&IDs BON-SHI-008-P-00002-009 Storage Compartment 1(Dirty Slop Tank) and BON-SHI-008-P-00002-010 Storage Compartment 2(Clean Slop Tank).

3.2.1 Clean and Dirty Slop Tank Slop Pumps P-2605A/B Control

Slop pumps are fitted in the bottom of the clean P-2605A and dirty P-2605B slop

tanks, which can discharge the contents into either the transfer or tank cleaningheaders. Although they both share a common discharge line, spectacle pieces areprovided which allow the starboard slop pump to be utilised as a back-up cleanwater overboard pump.

The Slops Pumps are operated remotely from the DCS System or from the FramoControl Panel. Individual controllers for all submerged pump motors are provided onthe Framo Control Panel installed in the CER.

All submerged pump controllers are calibrated from a minimum output where thehydraulic supply pressure to the pump motor is 0barg to a maximum output of260barg.

When the Slop Pumps are controlled from the DCS System, the set point from the

DCS Console is used by the PLC logic incorporated in the Framo Control Panel toadjust the hydraulic supply to the pump motor. To assume a smooth start-up of theSlop Pumps, the set point is limited to 60barg for 45 seconds. When this time periodhas elapsed, the hydraulic supply pressure will increase to match the requiredset point.

When stripping is in progress, the pumps are operated locally. For local operation atthe pump top, the manual flow control valve at the pump top plate is opened,the pump started from the DCS or Framo control panel and the system hydraulicpressure set to approximately 150barg. Pump control is then by manually closingthe flow control valve to raise the hydraulic pressure at the pump as required.

3.2.2 Oil Skimming Pump P-2603 Control

After being allowed to settle out in the port slop tank, and once the oil/waterinterface level is below about 10m ullage, oil is removed from the upper part of thetank by an Oil Skimming Pump into a cargo tank, via the Transfer Header.

Control of the pump is as described for the slop pumps in Paragraph 3.2.1.

The interface detector 26-LZT-036 and port slop tank level 26-LIT-032 readingsshow the operator when the skimming pump can be used to transfer oil, and whenthe water interface is at or below pump suction.

Start inhibit and pump trips are provided at a preset level of 70% on26-LIT-032 in the Slop Tanks in case of tank low level.

Start inhibit and pump trips are provided at a preset interface level of 70% on

26-LZT-036 in the Slop Tank to prevent water carryover to the cargo tanks.






3.2.3 Clean Slop Tank Clean Water Overboard Pump P-2602

Control of the pump is as described for the slop pumps in Paragraph 3.2.1.



ODME unitunavailable

Clean Water Pump P-2602 – ODME unit is unavailable(26-YZA-001) and 26-ZCV-056 is closed.

Low tank level Skimming Pump P-2603 – Inhibit start if tank level26-LIT-032 is less than 70%.

Dirty tank level Clean Water Pump P-2602 – Inhibit start if 26-ZCV-056 isnot open and 26-LIT-032 high alarm is active.

HPU not running All power packs are stopped.

Table 5.2 – Start Interlocks (STIL) – Slop Tank Pumps



High interface level Skimming Pump P-2603 – Stop pump if interface level26-LZT-036 is greater than 70%.

Tank level belowpump inlet26-LZHH-035

Skimming Pump P-2603 – Stop pump if level 26-LI-032is less than 70%. Stop Pumps P-2602 and P-2605Aif interface level is high.

Hydraulic tank lowlevel 54-LALL-209

Aux Hydraulic Unit A-5401 oil level low 54-LALL-209 tripsPumps P-2602, P-2603 and P-2605A/B.

Table 5.3 – Process Interlocks – Slop Tank Pumps

Note: Low Low Pressure 55-PZLL-101 and 55-PZLL-102 on the CIGM and DIGM,respectively, trips the cargo, slop and skimming pumps and shuts the mainoil export ESD Valve 26-SDV-121 at 200mm WG. During periods when theCIGM is not in use, the output from 55-PZT-101 should be inhibited fromtaking any executive action.

3.3 Oil Discharge Monitoring System

3.3.1 Control Panel

The ODME unit is used to analyse the oil content of the water pumped from theclean slop tank to check if the oil-in-water is below the regulatory amount, so that itcan be discharged overboard or, if off-specification, returned to the dirty slop tank.The ODMS provides high and high high oil-in-water alarms and a unit abnormal26-YZA-001 alarm, which is sent to the SSDS.






Control of the ODMS is through the control panel located in the control room.This panel is microprocessor based and uses a number of sub-programmes tointerrogate and control the analyser, then process and store the data received.The unit also provides the interface with the operator through an LED display

and keypad. Data logging is performed by printing out time-tagged key values andevents. The control panel receives input from the Oleometer cabinet, and from theoverboard flowmeter.

If the oil-in-water content exceeds 39ppm, the control panel provides a signal to thevalve control panel to open the Remote Operated Valve 26-ZCV-067 and closeOverboard Discharge Valve 26-ZCV-066 to prevent out-of-specification water beingdischarged overboard. The dirty water is diverted back to the port slop tank through26-ZCV-067.

3.3.2 Control Logic

When the transfer line isolation valve 26-ZCV-056 is closed and the Clean WaterPump P-2602 is started and confirmed to be running, and 26-PIT-036 is greater than0.5bar, the application will open the ODME recirculation valve 26-ZCV-067 and startthe ODME unit. If the valve fails to open or the ODME unit fails to start,the application will stop the ODME unit, close the valve, stop the pump and raisean alarm.

When the oil/water ratio falls below the preset value configured in the ODME unit,the ODME unit sends a low oil content signal (26-YZ-001) to the DCS, which willstart the overboard discharge sequence. The application then opens the overboarddischarge valve 26-ZCV-066 and closes the recirculation valve 26-ZCV-067. If eitherof the valves fails to reach its requested position, the application will stop the ODMEunit, close the discharge valve, stop the pump and raise an alarm.

The overboard discharge valve 26-ZCV-066 will be inhibited from opening for aperiod of 60 seconds (configurable) after the ODME unit has started even if theoil/water ratio falls below the required set point.

If the oil/water ratio rises above the unit set point, an alarm will be generated by theODME unit 26-YZA-001 and the application will stop the ODME unit. The cleanwater pump is stopped (54-YZC-221 driven to 0%), the recirculation valve(26-ZCV-067) opens and the overboard discharge valve 26-ZCV-066 closes.

The application will stop the clean water pump and the ODME unit if the ODME unitdetects a high oil content and the dirty slop tank high-high level 26-LZT-031is detected.

The status of the ODME unit is displayed on the DCS. The ODME unit can bemanually started and stopped by the operator and the running status, unit abnormalalarm 26-YZA-001 and the overboard discharge status can also be seen onthe HMI.






4.0 SAFEGUARDING

Protection against potential overfilling of the Slop Tanks is provided by the high-leveltrip signal from the Saab Radar System and the high high trip signal from theMetritape. The set points for all of the Slop Tank high level alarms is 95% and thehigh high trip signal is provided at 98% of the tank capacity.

The activation of the level alarm is annunciated in the DCS.

The slop tanks are protected against overpressurisation or vacuum conditionsthrough Pressure/Vacuum Valves 55-RV-018 and 55-RV-019 for the port andstarboard tanks respectively, connected to the Vent Main.

The relief valves each have two pressure settings, 1600mm WG to preventoverpressurisation conditions and -200mm WG (-0.2barg) to prevent vacuumconditions.

An inert atmosphere is maintained in the slop tanks by connection to the dirty inert

gas header that maintains a positive pressure on the tanks.To prevent pollution when water from the slop tanks is dumped overboard,the ODME is provided to monitor water quality and automatically divert water fordisposal to the dirty slop tank if water quality does not meet the regulatoryrequirements or on failure of the ODME.






065

03

064

(5C) T-2601N

P-2601N

062

DIRTY SLOP T-2603

059

P-2605B

(Slop)

117

PIT-033

bargXXX

LIT-032

XXX% LZT-031XXX I/F%

PIT-031

LIT-028

XXX%

LZT-027

047

bargXXX

042

048

108

109

110

063P-2603

bargXXX

P

P XXX

XXX

066

Overboard

067

T-2604

26-LIT-038

XXX%

A-5801

Start/Stop

Unit

Abnormal

Running/

Stoppped

High Oil

Content

xxx

54-SIC-220

xxx54-SIC-219

55-PIT-104

bargXXX

Dirty IGGHeader

55-PIT-103

bargXXX

Clean IGG

Header

55-PIT-001

bargXXX

N2 Header

%

%

xxx54-SIC-217

056

068

LZT-036

YZC-004

YZA-001

YZ-003

YZ-001

Hydraulic Valve

HPU

Hydraulic HPU

Running/

StoppedRunning/

Stopped

PIT-035


OPRM-2003-0304 Page 13 of 13




PART 2

OPERATING PROCEDURES

Section 1 System Operating Procedures

Section 2 Equipment Operating Procedures

Section 3 Supplementary Operating Procedures

Part 2 Operating Procedures





Part 2Operating Procedures

Section 1System Operating Procedures

ProcedureNumber

CARGO LOADING AND BALLAST SYSTEMS OPERATING PROCEDURES

PROCEDURE NO 1/001: LOADING FACILITIES OPERATIONS (INITIAL)

PROCEDURE NO 1/002: BALLAST OPERATIONS

Part 2 Section 1 System Operating Procedures





SYSTEM/EQUIPMENT: OIL STORAGE, HANDLING AND BALLAST

PROCEDURE NO 1/001: LOADING FACILITIES OPERATIONS (INITIAL)

THE WHOLE OF THIS PROCEDURE MUST BE READ THROUGH ANDFULLY UNDERSTOOD BEFORE CARRYING OUT ANY OF THE

FOLLOWING ACTIONS.

INTRODUCTION

This procedure details the operator actions required to be carried out on the Cargo System

prior to and during start-up of loading operations. In the procedure it is assumed that CrudeOil Tanks (COT) 2 and 4 in Group A are to be filled first. Loading can be by two methods –via the reception tank or directly to the individual Cargo Tanks. The reception tank isthe preferred method as it gives less likelihood of stopping production due toerroneous-manipulation of valves and ensures that any water entrained in the crude oil iscontained in a single tank.

Checklist No 1 indicates all the system valves that are required to be shut prior to loading atstart-up.

Checklist No 2, together with a small written procedure, indicates loading valve positions forloading via reception tank 3C to group A tanks.

Checklist No 3, together with a small written procedure, indicates loading valve positions forloading directly to group A tanks.

PRECONDITIONS

Supporting Drawings

The procedure utilises the following P&IDs:







• BON-SHI-008-P-00002-018 Tank Cleaning and Nitrogen Headers

• BON-SHI-008-P-00002-019 to 24 Storage Compartments 1 to 7 Tank Cleaningand Utilities

Supporting Document

•

Framo Doc 9242-0169-4 – Service Manual for Cargo Pumping






Interface Systems

Before cargo loading can take place the following systems are required to be operational:

• Inert Gas System. Refer to POPM Volume 19 (OPRM-2003-0319)

• Seawater System. Refer to POPM Volume 21 (OPRM-2003-0321)

• Fresh and Potable Water Systems. Refer to POPM Volume 22 (OPRM-2003-0322)

• Instrument and Utility Air System. Refer to POPM Volume 25 (OPRM-2003-0325)

• Power Generation and Distribution System. Refer to POPM Volume 30(OPRM-2003-0330)

• Deck Hydraulic Systems. Refer to POPM Volume 33 (OPRM-2003-0333)

Pre-requisites

• No Work Permits are in force that will prohibit any part of this Procedure and all relevantHot Work Tags have been returned to the Installation Control Centre

• Fire, Gas and Safety Systems are commissioned and are in readiness for operation

• Special Safety considerations: Shell Export Safety Manual of Safe Handling ofChemicals for the use of all chemicals added to the upstream Crude Oil ProductionFacilities

• If the loading sequence for the Cargo Oil Tanks is following a Tank Inspection, the statusof the tanks is as follows:

− All Cargo Oil Tanks are totally empty, oxygen free and charged with inert gas atapproximately 800mm WG

− All submerged Cargo Oil Pumps are available for operation

− The bottom transfer mains interconnecting adjacent Cargo Oil Tanks are unrestrictedand available for use

• Assuming all Cargo Tanks are empty, the status of the Ballast Tanks is as follows:

− The Aft Peak Water Ballast Tank (APWBT) is empty but available for use

− The Port and Starboard Water Ballast Tanks (WBTs) 1 to 6 contain seawater

− The Forward Peak Water Ballast Tank (FPWBT) is empty but available for use

− The Port and Starboard Submerged Ballast Pumps are available for operation

− The Port and Starboard Ballasting lines interconnecting all WBTs are availablefor use

− The Port (Dirty) and Starboard (Clean) Slop Tanks are available for use

− The Cargo Oil Transfer Main is available for use

• The following tank systems are isolated:

− Nitrogen Header

− Clean Inert Gas Main

PLANT STATUS

Initially the system isolation valves are all closed as indicated in Valve Checklist No 1.






VALVE CHECKLIST No 1: PRE-START POSITIONS CARGO TANKS 1 TO 5

Tag No Function Setting Checked

Pre-start Positions: Cargo Oil Tank Nos 1P, C&SRefer to P&ID BON-SHI-008-P-000002-008

26-ZCV-130 Isolation Valve on Cargo Pump commondischarge to Discharge Header

CLOSED

26-ZCV-131 Isolation Valve on Cargo Pump commondischarge to Transfer Header

CLOSED

No 1 Port Cargo TankRefer to P&ID BON-SHI-008-P-000002-015

26-ZCV-031 Cargo Pump P-2601C discharge isolationvalve

CLOSED

26-BLV-001 Cargo Pump P-2601C stripping isolation valve CLOSED

26-BUV-018 Manual Isolation Valve for Portable CargoPump discharge

CLOSED

26-ZCV-071 Lower transfer line to No 2P COT CLOSED

Refer to P&ID BON-SHI-008-P-000002-018

26-BUV-073 COTs 1P, 1C and 1S Isolation valve fromCOW Header

CLOSED


26-GTV-001 COT 1P Isolation Valve from COW line to TankTop machine

CLOSED


CLOSED


CLOSED

26-SV-009 COT 1P Isolation Valve for portable tankcleaning pump

CLOSED

No 1 Centre Cargo TankRefer to P&ID BON-SHI-008-P-000002-015

26-ZCV-032 Cargo Pump P-2601B discharge isolationvalve

CLOSED

26-BLV-002 Cargo Pump P-2601B stripping isolation valve CLOSED


CLOSED

26-ZCV-073 Lower transfer line to No 2C COT CLOSED


26-GTV-037 COT 1C Isolation Valve from COW line tosubmerged machine

CLOSED






VALVE CHECKLIST No 1: PRE-START POSITIONS CARGO TANKS 1 TO 5 (cont’d)




CLOSED

26-GTV-003 COT 1C Isolation Valve from COW line to TankTop machine

CLOSED


CLOSED


CLOSED

26-SV-010 COT 1C Isolation Valve for portable tankcleaning pump

CLOSED

No 1 Starboard Cargo TankRefer to P&ID BON-SHI-008-P-000002-015

26-ZCV-033 Cargo Pump P-2601A discharge isolationvalve

CLOSED

26-BLV-003 Cargo Pump P-2601A stripping isolation valve CLOSED


CLOSED

26-ZCV-075 Lower transfer line to No 2S COT CLOSED


26-GTV-005 COT 1S Isolation Valve from COW line to TankTop machine

CLOSED


CLOSED


CLOSED

26-SV-011 COT 1S Isolation Valve for portable tankcleaning pump

CLOSED

Pre-start Positions: Cargo Oil Tank Nos 2 P, C&SRefer to P&ID BON-SHI-008-P-000002-008


CLOSED


CLOSED








No 2 Port Cargo Tank Refer to P&ID BON-SHI-008-P-000002-014




26-ZCV-034 Cargo Pump P-2601F discharge isolation valve CLOSED

26-BLV-004 Cargo Pump P-2601F stripping isolation valve CLOSED


CLOSED



CLOSED



CLOSED


CLOSED


CLOSED


CLOSED


26-ZCV-035 Cargo Pump P-2601D discharge isolationvalve

CLOSED

26-BLV-005 Cargo Pump P-2601D stripping isolation valve CLOSED


CLOSED

26-BUV-061 Cargo Pump P-2601D discharge isolation

valve of diesel during start-up

CLOSED














CLOSED


CLOSED


CLOSED

26-SV-013 COT 2C Isolation Valve for portable tank

cleaning pump

CLOSED


26-ZCV-036 Cargo Pump P-2601E discharge isolationvalve

CLOSED

26-BLV-006 Cargo Pump P-2601E stripping isolation valve CLOSED


CLOSED






CLOSED


CLOSED


CLOSED

26-SV-014 COT 2S Isolation Valve for portable tank

cleaning pump

CLOSED










CLOSED


CLOSED

No 3 Port Cargo Tank Refer to P&ID BON-SHI-008-P-000002-013

26-ZCV-037 Cargo Pump P-2601I discharge isolation valve CLOSED

26-BLV-007 Cargo Pump P-2601I stripping isolation valve CLOSED


CLOSED





CLOSED



CLOSED


CLOSED


CLOSED


CLOSED


26-ZCV-038 Cargo Pump P-2601H discharge isolationvalve

CLOSED

26-ZCV-040 Cargo Pump P-2601H discharge isolationvalve

CLOSED

26-ZCV-041 Cargo Pump P-2601H discharge isolationvalve to dirty slop tank

CLOSED








26-BLV-017 Cargo Pump P-2601H stripping isolation valve CLOSED


CLOSED

26-ZCV-101 Upper cascade line on 3C COT CLOSED


26-ZCV-086 Lower transfer line to 3C suction CLOSED




CLOSED


CLOSED


CLOSED


CLOSED


CLOSED


CLOSED


26-ZCV-039 Cargo Pump P-2601G discharge isolationvalve

CLOSED

26-BLV-008 Cargo Pump P-2601G stripping isolation valve CLOSED


CLOSED

26-BUV-060 Cargo Pump P-2601G Isolation Valve on tie-infor discharge of diesel during start-up

CLOSED

26-ZCV-090 Lower transfer line to No 4S COT CLOSED26-ZCV-119 Lower transfer line to No 2S COT CLOSED










CLOSED


CLOSED


CLOSED


CLOSED



CLOSED


CLOSED


26-ZCV-043 Cargo Pump P-2601L discharge isolation valve CLOSED

26-BLV-009 Cargo Pump P-2601L stripping isolation valve CLOSED

26-BUV-027 Manual Isolation Valve for Portable Cargo

Pump discharge

CLOSED






CLOSED


26-GTV-019 COT 4P Isolation Valve from COW line to Tank

Top machine

CLOSED


CLOSED


CLOSED


CLOSED








No 4 Centre Cargo Tank


26-ZCV-044 Cargo Pump P-2601K discharge isolationvalve

CLOSED

26-BLV-018 Cargo Pump P-2601K stripping isolation valve CLOSED


CLOSED







CLOSED


CLOSED

26-GTV-049 COT 4C Isolation Valve from COW line to TankTop

CLOSED


CLOSED


CLOSED


CLOSED


26-ZCV-045 Cargo Pump P-2601J discharge isolation valve CLOSED

26-BLV-019 Cargo Pump P-2601J stripping isolation valve CLOSED


CLOSED













CLOSED


CLOSED


CLOSED


CLOSED

Cargo Oil Tank Nos 5 P, C&SRefer to P&ID BON-SHI-008-P-000002-008


CLOSED


CLOSED


26-ZCV-046 Cargo Pump P-2601O discharge isolationvalve

CLOSED

26-BLV-010 Cargo Pump P-2601O stripping isolation valve CLOSED

26-BUV-030 Manual Isolation Valve for Portable CargoPump discharge CLOSED




26-BUV-067 Isolation Valve on COW Header to No 5 COTsPC&S

CLOSED



CLOSED

26-GTV-026 COT 5P Isolation Valve from COW line to TankTop

CLOSED

26-GTV-053 COT 5P Isolation Valve from COW line to TankTop

CLOSED


CLOSED









26-ZCV-047 Cargo Pump P-2601N discharge isolationvalve

CLOSED

26-ZCV-048 Cargo Pump P-2601N discharge isolationvalve

CLOSED

26-ZCV-042 Cargo Pump P-2601N to dirty slop tank CLOSED

26-BLV-011 Cargo Pump P-2601N stripping isolation valve CLOSED

26-BUV-031 Manual Isolation Valve on tie-in for PortableCargo Pump discharge

CLOSED


26-ZCV-102 Upper cascade line from 5C COT CLOSED



26-ZCV-107 Lower transfer line to 5C COT CLOSED



CLOSED

26-GTV-028 COT 5C Isolation Valve from COW line to Tank

Top machine

CLOSED


CLOSED


CLOSED


CLOSED


CLOSED

No 5 Starboard Cargo Tank


26-ZCV-049 Cargo Pump P-2601M discharge isolationvalve

CLOSED

26-BLV-012 Cargo Pump P-2601M stripping isolation valve CLOSED

26-BUV-032 Manual Isolation Valve on tie-in for PortableCargo Pump discharge

CLOSED












CLOSED


CLOSED


CLOSED






PRE-START CHECKS AND CONDITIONS

Step Action

1 CHECK that all Instrument Isolating Valves are OPEN.

2 CHECK that all Sample Point Isolation Valves are CLOSED and blanked.

3 CHECK that the ESS System is healthy, with any previous ESS being RESET.

4 CHECK that Isolation Valves are in the closed position as indicated in the followingValve Checklist 1 Pre-start Positions:

• Cargo Oil Tank No 1 Port, Centre and Starboard



• Crude Oil Tank No 4 Port, Centre and Starboard


Note: The initial line-up of closed valves are itemised in Valve Checklist 1. Whereindicated in the text, Checklists 2 and 3 are used in the separate proceduresfor tank filling which follow.

5 ENSURE that the Nakakita Hydraulic System is operating normally andhigh-pressure hydraulic oil is available at 90barg. The Nakakita Local Control Panelmust be SET to Remote control to allow the Isolation Valves to be OPENED andCLOSED from the DCS Console in the DCS.

6 CONFIRM that the oxygen concentration in the Inert Gas System is less than 5%(Volume).

7 CONFIRM that the Dirty Inert Gas Main (DIGM) is connected and open to all Cargoand Slop Tanks.

CARGO LOADING MUST NOT PROCEED UNTIL ALL CARGO OIL TANKS AREFILLED WITH INERT GAS. THIS IS TO PREVENT ANY INGRESS OF OXYGEN

THAT COULD RESULT IN A POTENTIALLY HAZARDOUS ATMOSPHERE

WITHIN THE TANKS.

8 ENSURE that the overflow from the Flare Scrubber V-4640 is lined up to either thedirty slop tank or the primary reception tank.

9 Prior to commencement of Cargo Loading or any Ballasting adjustments, a completesimulation of the Loading Sequence must be completed by the Loading Computer.

10 The Loading Plan has been issued by the Marine Supervisor and approved bythe OIM.






PROCEDURE FOR LOADING VIA RECEPTION TANK 3C TO GROUP ATANKS NOS 2 AND 4

The system isolation valves are positioned as indicated in the following Valve Checklist No 2.

VALVE CHECKLIST No 2: PRE-START POSITIONS: LOADING VIA RECEPTIONTANK 3C TO GROUP A TANKS (NOS 2 AND 4)



26-BUV-001 Fwd Isolation Valve on loading header OPEN

26-ZCV-009 Isolation Valve on loading header Fwdof Import

OPEN

26-GBV-023 Drain Valve between 26-BUV-001 and26-ZCV-009

CLOSED

26-BUV-011 Aft Isolation Valve on loading header OPEN

26-ZCV-022 Isolation Valve on loading header Aft of Import OPEN

26-GBV-024 Drain Valve between BUV-011 and ZCV-022 CLOSED

26-ZCV-010 Master Isolation Valve on No 1 COTsloading header

CLOSED


26-ZCV-011 COT 1P Loading Valve CLOSED

26-BUV-002 COT 1P Manual Isolation Valve OPEN

26-ZCV-012 COT 1C Loading Valve CLOSED

26-BUV-003 COT 1C Manual Isolation Valve OPEN

26-ZCV-013 COT 1S Loading Valve CLOSED

26-BUV-004 COT 1S Manual Isolation Valve OPEN


26-ZCV-014 Master Isolation Valve No 2 COTsloading Header

CLOSED













VALVE CHECKLIST No 2: PRE-START POSITIONS: LOADING VIA RECEPTIONTANK 3C TO GROUP A TANKS (NOS 2 AND 4) (cont’d)



26-ZCV-018 Master Isolation Valve No 3 COTsLoading Header

OPEN


26-ZCV-019 COT Loading Valve CLOSED


26-ZCV-020 COT 3C Loading Valve OPEN



26-BUV-010 COT 3S manual Isolation Valve OPEN



CLOSED










CLOSED


26-ZCV-028 Actuated Valve on loading header toNo 5P COT

CLOSED

26-BUV-015 Manual Valve on loading header toNo 5P COT

OPEN

26-ZCV-029 Actuated Valve on loading header toNo 5C COT

CLOSED

26-BUV-016 Manual Valve on loading header toNo 5C COT

OPEN

26-ZCV-030 Actuated Valve on loading header toNo 5S COT

CLOSED






VALVE CHECKLIST No 2: PRE-START POSITIONS: LOADING VIA RECEPTIONTANK 3C TO GROUP A TANKS (NOS 2 AND 4) (cont’d)


Before Reception Tank 3C Reaches 70% FullRefer to P&ID BON-SHI-008-P-000002-013

26-ZCV-101 Skim valve 70% line in 3C OPEN

26-ZCV-084 Lower transfer line to No 4C COT (in 4C) OPEN


26-ZCV-086 Lower transfer line 3C suction (0%) CLOSED




26-ZCV-076 Valve 2C – 2P levelling (2C) OPEN

26-ZCV-077 Valve 2C – 2P levelling (2P) OPEN

26-ZCV-078 Valve 2C – 2S levelling (2S) OPEN

26-ZCV-079 Valve 2C – 2S levelling (2C) OPEN


26-ZCV-091 Valve 4C – 4P levelling (4C) OPEN

26-ZCV-092 Valve 4C – 4P levelling (4P) OPEN

26-ZCV-093 Valve 4C – 4S levelling (4S) OPEN

26-ZCV-094 Valve 4C – 4S levelling (4C) OPEN






PROCEDURE FOR LOADING VIA RECEPTION TANK C TO GROUP ATANKS NOS 2 AND 4


FOLLOWING ACTIONS.

THE CARGO LOADING OPERATION CANNOT COMMENCE UNTIL THEDECK HYDRAULIC SYSTEMS ARE PRESSURISED AND THE INERT GAS

SYSTEM IS OPERATING NORMALLY.

PREAMBLE

This Procedure covers the start-up of the Cargo System after a major planned shutdown. After completion of the Procedure, the cargo of crude oil may be offloaded to the OfftakeTanker, as detailed in POPM Volume 5 Oil Metering and Export System (OPRM-2003-0305).

Ballast changes are required as cargo is taken onboard. The Procedure for Ballast Changesis detailed in Procedure No 1/002.

As an example the general outline for the start-up of the Cargo System is as follows:• Fill Reception Tank 3C to 70%

• Cascade to No 2C and 4C COTs

• Simultaneously transfer by gravity to No 2 (Port and Starboard) and 4(Port and Starboard) wing COTs (Group A tanks)

• Further transfer of cargo may be either by gravity or pumped from No 2C and 4C

• Reduce Ballast in accordance with the approved Loading Plan

• Offload to export tanker when sufficient cargo is available

Pre-requisites

The Crude Oil Production facilities are PREPARED for start-up. (The level control valve forthe Oil Degassing Tank V-2344 located downstream of Crude Cooler E-2540C regulates theflowrate of stabilised crude oil from the production facilities to the crude oil loading header.)

The Loading Header is lined up to fill Cargo Tank 3C.

The Water Ballast System is PREPARED for operation as described in Procedure No 1/002.

The Port and Starboard Slop tanks are AVAILABLE for use.

ENSURE de-ballasting is carried out as per loading plan.






PROCEDURE

Step Action

1 START UP the Oil Production System.

2 MONITOR the rising oil level in the reception tank from the DCS console.

3 MONITOR the operating pressure in the cargo tanks and DIGM.

4 OPEN the cascade system to Nos 2C and 4C COT by OPENING valves26-ZCV-084/085/087/088 and 26-ZCV-101.

Note: As the level reaches 70% oil will flow to Cargo Tanks 2C and 4C.

5 OPEN levelling valves between No 2C and No 2 Port and Starboard Wing COTs,and No 4C and 4 Port and Starboard Wing COTs, as shown below.

Levelling Valves Port Starboard

No 2 Cargo Tanks 26-ZCV-076/077 26-ZCV-078/079

No 4 Cargo Tanks 26-ZCV-091/092 26-ZCV-093/094

Group A Tanks are now being loaded:

6 MONITOR the rising oil level in the Group A Tanks COT 2 and 4 Port, Centreand Starboard.

7 DE-BALLAST as required in line with the loading plan.

8 CONTINUE to monitor individual tank levels in Group A.

9 CLOSE the levelling valves as the level approaches 90% to the individual wingtanks as listed above.

Note: The reception tank level will rise above 70% and lead the levels in the othertanks. The wing tanks will be later topped off to 95% using a suitable cargo pump and the transfer header.

10 CONTINUE to load by gravity.

When the wing tanks are at 90%:

11 CLOSE the levelling valves to the corresponding centre tank and OPEN the levellingvalves between adjacent Centre Tanks 2C to 1C, and 4C to 5C as shown below.

Levelling Valves 2C – 1C 4C – 5C

26-ZCV-072/073 26-ZCV-097/098

12 If it is intended to continue loading by pumping from 2C and 4C COT it should bestarted by topping up COT 2 and 4 Wing Tanks to 95%, then fill COT 2C and 4Cto 90%.

13 Pump from 2C and 4C to the Group B tanks, in general to the Centre COTs(1C and 5C) first followed by the wing tanks.






Step Action

14 This will be an intermittent operation as crude oil becomes available in COTs 2C

and 4C, FILL 2C and 4C to 70%.

15 PUMP crude to the selected Group B tanks until 2C and 4C are reduced to 10%.

16 REPEAT until Group B tanks are full or until discharge to an export tanker starts.

Notes:

(1) At this stage there is enough crude onboard to export if a tanker is available.

(2) It is possible to open the levelling valves between Nos 1 and 2 across COTand Nos 4 and 5 across COT; it is good operating practice to restrict thenumber of tanks common to each other.

17 CONTINUE loading by gravity.

WHEN COTs 2C/1C and 4C/5C are at a level of 85%:

18 OPEN the levelling valves between COT 2 and 1 wings (26-ZCV-070/071/074/075)and between COT 4 and 5 wings (26-ZCV-095/096/099/100) until the tanks arelevel, CLOSE the valves.

WHEN COTs 2C and 4C reach 90%:

19 OPEN (simultaneously) the levelling valves between 2C and 2 wings, and CLOSEthe levelling valves between COTs 2C an 1C.


20 OPEN (simultaneously) the levelling valves between COTs 4C and 4 wings, and

CLOSE the levelling valves between COTs 4C and 5C.

Note: When the tanks reach 90%, any remaining cargo transfer and topping offtanks will be by cargo pump.


21 LEVEL COTs 1 and 2 (and 4 and 5) wing tanks via the levelling valves (to 90%).

22 Close the levelling valves.

23 CONTINUE to fill COTs 2C and 4C to 90%.

24 FILL all other tanks via the cargo pumps to the required level.






PROCEDURE FOR DIRECT LOADING TO GROUP A TANKS, NOS 2 AND 4

The system isolation valves are positioned as indicated in the following Valve Checklist.

VALVE CHECKLIST No 3: PRE-START POSITIONS: DIRECT LOADING TO GROUP ATANKS (NOS 2 AND 4)



26-BUV-001 Fwd Isolation Valve on loading header OPEN

26-ZCV-009 Isolation Valve on loading header Fwd ofImport

OPEN

26-GBV-023 Drain Valve between 26-BUV-001 and

26-ZCV-009

CLOSED

26-BUV-011 Aft Isolation Valve on loading header OPEN

26-ZCV-022 Isolation Valve on loading header Aft of Import OPEN

26-GBV-024 Drain Valve between BUV-011 and ZCV-022 CLOSED

26-ZCV-010 Master Isolation Valve on No 1 COTs LoadingHeader

CLOSED



26-BUV-002 COT 1P Manual Loading Valve OPEN


26-BUV-003 COT 1C Manual Loading Valve OPEN


26-BUV-004 COT 1S Manual Loading Valve OPEN



OPEN


26-ZCV-015 COT 2P Loading Valve OPEN26-BUV-005 COT 2P Manual Loading Valve OPEN



26-ZCV-017 COT 2S Loading Valve OPEN







VALVE CHECKLIST No 3: PRE-START POSITIONS: DIRECT LOADING TO GROUP ATANKS (NOS 2 AND 4) (cont’d)




CLOSED










OPEN


26-ZCV-024 COT 4P Loading Valve OPEN




26-ZCV-026 COT 4S Loading Valve OPEN




CLOSED













PROCEDURE FOR DIRECT LOADING TO GROUP A TANKS NOS 2 AND 4


FOLLOWING ACTIONS.

THE CARGO LOADING OPERATION CANNOT COMMENCE UNTIL THEDECK HYDRAULIC SYSTEMS ARE PRESSURISED AND THE INERT GAS

SYSTEM IS AVAILABLE.

PREAMBLE

This Procedure will be used if the Reception Tank 3C that is normally used is out of service.

PROCEDURE

Step Action

1 ENSURE the Crude Oil Production facilities are PREPARED for start-up. The LevelController on the Crude Oil Cooler will REGULATE the flowrate of Stabilised CrudeOil from the Production Facilities to the Crude Oil Loading Header.

2 ENSURE the Water Ballast System is PREPARED for Cargo Loading as describedin Procedure No 1/002.

3 ENSURE the Primary and Secondary Slop Tanks are AVAILABLE for use.

4 START UP the Oil Production System. Once Crude Oil production is established inthe Stabilised Crude, oil will be passed from the topside process system through theCrude Coolers to the Loading Header. The Loading Header then directs the crudeoil through the Crude Oil Loading Mains to the Group A Cargo Tanks.

Note: If the produced oil/water content is high, the crude should be directed toReception Tank 3C until the produced oil has a BS&W of less than 0.5%.

5 MONITOR the rising oil level in the Group A tanks, COT 2 and 4 Port, Centre andStarboard from the DCS Console. Also OBSERVE the operating pressure in theCargo Tanks and DIGM.

6 As the level in Group A COT approaches 50%, start pumping out ballast asdescribed in Procedure No 1/002 and in accordance with the Loading Plan.

7 CARRY OUT a daily TANK SOUNDING to determine the amount of water in theCargo Tanks. If there is sufficient to justify removal, pump out the water from thetank to the port slop tank using a cargo pump and the transfer line.






Step Action

8 CONTINUE to monitor individual tank levels in Group A as the level approaches

95% in the tanks. Open the valves on the headers and drop lines to Group B COTsand isolate each Group A tank as it reaches 95% level by closing the respectivetank valve. When all Group A tanks are complete, close the isolation valves on theloading headers to those tanks.

Isolation Valves Cargo Tanks and Headers

Group A

No 2 PC&S Cargo Tank 26-ZCV-015 26-ZCV-016 26-ZCV-017

No 2 loading header isolation 26-ZCV-014



Group B







9 Perform Tank Sounding to determine water level in the Group A COTs. Removeexcess water as described in the Procedure in Offloading Facilities in POPMVolume 5 Oil Metering and Export System (OPRM-2003-0305).

10 When water is removed from the Group A COTs, top-off the COTs by opening theindividual tank drop lines and closing when the level reaches 95%.

11 The Group A tanks are now ready for transfer to an export tanker as described inPOPM Volume 5 Oil Metering and Export System (OPRM-2003-0305), Group Btanks are filling and further ballast adjustments should be made as identified in theLoading Plan.






SYSTEM/EQUIPMENT: OIL STORAGE, HANDLING AND BALLAST

PROCEDURE NO 1/002: BALLAST OPERATIONS


FOLLOWING ACTIONS.

INTRODUCTION

This Procedure details the operator actions required to be carried out on the Ballast System

prior to and during loading/offloading operations. In the procedure it is assumed that Group ACargo Tanks (COT 2 and 4) are to be filled first and offloaded first. Similar Procedures will berequired when loading via the reception tank.

The Ballast System has a semi-automatic function for ballasting, de-ballasting and lineflooding. This function can be overridden to give manual control. Interlocks on the DCSensure only two ballast pumps can be operated at a time, normally one each port andstarboard.

The ballast ringmain is constructed of GRP and, under some circumstances, could besusceptible to surge damage if not completely filled with seawater. Whilst a system is fitted towarn of an empty ringmain, it is good operating practice when starting to ballast empty tanksto start by either using the flooding procedure or restricting the pump speed until the tanklevel is seen to start rising.

PRECONDITIONS

Supporting Drawings

The procedure utilises the following P&IDs:

• BON-SHI-008-P-00002-001 and 002 Ballast System

• BON-SHI-008-P-00002-004 Air and Sounding System (1/2)

Interface Systems

Before ballast operations can take place, the following systems are required to beoperational:

• Sludge and Bilge Systems. Refer to POPM Volume 18 (OPRM-2003-0318)

• Seawater System. Refer to POPM Volume 21 (OPRM-2003-0321)

• Fresh/Potable Water System. Refer to POPM Volume 22 (OPRM-2003-0322)

• Instrument and Utility Air System. Refer to POPM Volume 25 (OPRM-2003-0325)

• Power Generation and Distribution System. Refer to POPM Volume 30(OPRM-2003-0330)

• Deck Hydraulic Systems. Refer to POPM Volume 33 (OPRM-2003-0333)






Pre-requisites

No Work Permits are in force that will prohibit any part of this Procedure and allrelevant Hot Work Tags have been returned to the Installation Control Centre.Fire, Gas and Safety Systems are commissioned and are in readiness for operation.

PLANT STATUS

The system isolation valves are positioned as indicated in the following Valve Checklists.Valve Checklist No 1 indicates that all main Ballast Ringmain Valves are closed.

• Valve Checklist No 1: Start-up positions: Ballast Pumps (indicates initially all BallastPump Valves are closed)

• Valve Checklist No 2: Start-up positions port Ballast Main (indicates initially all portBallast Main Valves are closed with the exception of 58-ZCV-147)

• Valve Checklist No 3: Start-up positions starboard Ballast Main (indicates initially all

starboard Ballast Main Valves are closed with the exception of58-ZCV-148)

Assuming all Cargo Tanks are empty, the status of the Ballast Tanks at start of loading isas follows:

• The APWBT is empty but available for use

• The Port and Starboard WBTs 1 to 6 contain seawater

• The FPBT is empty but available for use

• The Port and Starboard submerged Ballast Pumps are available for operation

• The Port and Starboard Ballast Lines interconnecting all WBTs are available for use

Assuming all Group A Cargo Tanks are full, the status of the Ballast Tanks at start ofoffloading is as follows:

• The APWBT is empty but available for use

• The Port and Starboard WBTs 1 and 4 are empty, No 3 WBTs are reduced to6100 tonnes and No 6 WBTs are reduced to 1700 tonnes

• The FPBT is empty but available for use

• The Port and Starboard submerged Ballast Pumps are available for operation

• The Port and Starboard Ballast Lines interconnecting all WBTs are available for use

• Cargo offloading main is available for use






VALVE CHECKLIST No 1: START-UP POSITIONS: BALLAST PUMPS


Refer to P&ID BON-SHI-008-000002-001Port Ballast Pump

58-ZCV-103, 106 Actuated Valves on suction from port ballastmain

CLOSED

58-ZCV-101 1st in-line Actuated Valve on suction from portsea chest

CLOSED

58-ZCV-102, 105 2nd in-line Actuated Valves on suction fromport sea chest

CLOSED

58-ZCV-104, 107 Actuated Valves on discharge from port ballastpump

CLOSED

58-ZCV-145 Actuated Valve on pump discharge overboard CLOSED

58-ZCV-149 Actuated Valve on pump discharge to portballast main

CLOSED

Starboard Ballast Pump

58-ZCV-110, 113 Actuated Valve on suction from starboardballast main

CLOSED

58-ZCV-108 1st in-line Actuated Valve on suction fromstarboard sea chest

CLOSED

58-ZCV-109, 112 2nd in-line Actuated Valve on suction fromstarboard sea chest

CLOSED

58-ZCV-111, 114 Actuated Valve on discharge from starboardballast pump

CLOSED

58-ZCV-146 Actuated Valve on pump discharge overboard CLOSED

58-ZCV-150 Actuated Valve on pump discharge tostarboard ballast main

CLOSED

58-BUV-102 Manual Valve on pump discharge to tankcleaning line

CLOSED

58-BUV-101 Manual Valve on pump discharge to cargotransfer header

CLOSED






VALVE CHECKLIST No 2: START-UP POSITIONS: PORT BALLAST MAIN


Refer to P&ID BON-SHI-008-000002-001/002

58-ZCV-147 Port ballast main actuated section isolationvalve at No 4 WBT

OPEN

58-ZCV-141 Port ballast main actuated section isolationvalve at FPT

CLOSED

58-ZCV-139 Actuated Valve at FPT Suction/Dischargenozzle

CLOSED

58-ZCV-115 Actuated Valve at 1st No 1 P WBTSuction/Discharge nozzle

CLOSED

58-ZCV-116 Actuated Valve at 2nd No 1 P WBT

Suction/Discharge nozzle

CLOSED

58-ZCV-119 Actuated Valve at 1st No 2 port WBTSuction/Discharge nozzle

CLOSED

58-ZCV-120 Actuated Valve at 2nd No 2 port WBTSuction/Discharge nozzle

CLOSED


CLOSED

58-ZCV-124 Actuated Valve at 2nd No 3 WBTSuction/Discharge nozzle

CLOSED


CLOSED


CLOSED


CLOSED


CLOSED


CLOSED


CLOSED

58-ZCV-143 Actuated Valve at Aft peak tankSuction/Discharge nozzle

CLOSED






VALVE CHECKLIST No 3: START-UP POSITIONS: STARBOARD BALLAST MAIN


Refer to P&ID BON-SHI-008-000002-001/002

58-ZCV-148 Stbd ballast main actuated section isolationvalve at No 4 WBT

OPEN

58-ZCV-142 Stbd ballast main actuated section isolationvalve at FPT

CLOSED

58-ZCV-140 Actuated Valve at FPT Suction/DischargeNozzle

CLOSED

58-ZCV-117 Actuated Valve at 1st No 1S WBTSuction/Discharge nozzle

CLOSED

58-ZCV-118 Actuated Valve at 2nd No 1S WBT

Suction/Discharge nozzle

CLOSED

58-ZCV-121 Actuated Valve at 1st No 2 Stbd WBTSuction/Discharge nozzle

CLOSED

58-ZCV-122 Actuated Valve at 2nd No 2 Stbd WBTSuction/Discharge nozzle

CLOSED


CLOSED

58-ZCV-126 Actuated Valve at 2nd No 3 WBTSuction/Discharge nozzle

CLOSED


CLOSED


CLOSED


CLOSED


CLOSED


CLOSED


CLOSED

58-ZCV-144 Actuated Valve at Aft peak tankSuction/Discharge nozzle

CLOSED






PRE-START CHECKS AND CONDITIONS

Step Action

1 CHECK that Isolation Valves are positioned as indicated in the following ValveChecklists:

• Valve Checklist 1 Pre-start Positions: Ballast Facilities

• Valve Checklist 2 Pre-start Positions: Port Ballast Main and Tanks

• Valve Checklist 3 Pre-start Positions: Starboard Ballast Main and Tanks

2 ENSURE that the Nakakita Valve Hydraulic System is operating normally andhigh-pressure hydraulic oil is available at 90barg for the operation of the isolationvalves. The Nakakita Local Control Panel must be set to Remote control to allow theIsolation Valves to be OPENED and CLOSED from the DCS Console in the CCR.

3 Prior to commencement of Cargo Loading or any Ballasting adjustments, a completesimulation of the Loading Sequence must be completed on the Loading Computer.

4 The Loading/Ballast Plan has been issued by the Marine Supervisor and approvedby the OIM.

5 ENSURE that the Framo Hydraulic System is operating normally and high-pressurehydraulic oil is available for operation of the Ballast Pump Motors. The FramoControl Panel must be set to Remote control to allow the Ballast Pumps to beoperated from the DCS Console.

6 ENSURE that the set points for the Ballast Pump Speed Controllers are set to zeroon the DCS Console.







FOLLOWING ACTIONS.

NORMALLY BALLAST WATER WILL BE TRANSFERRED EITHER INTO THEHULL, OUT OF THE HULL, OR GRAVITATED BETWEEN TANKS (ONE

OPERATION AT ANY ONE TIME).

BALLAST WATER CANNOT BE PUMPED FROM TANK TO TANK.

THE CARGO PLANNING PROCEDURE MUST BE COMPILED AT ALLTIMES WHEN TRANSFERRING WEIGHTS WITHIN THE HULL.

PROCEDURE FOR DE-BALLASTING (MANUAL OPERATION)

Step Action

1 When the requirement to de-ballast is identified in the loading plan, check on theLoad Computer that during the intended ballast changes the vessel is and willremain within permissible trim, stability and stress limits. For this procedure it isassumed that de-ballasting will take place using ballast pumps P-5804A and C,initially from No 2 WBT followed by No 4, No 3 and No 6 P&S WBTs during the

loading of the Group A Cargo Tanks. Only the 20in suction valves in each BallastTank are used during normal de-ballasting operations.

2 OPEN the Isolation Valves 58-ZCV-103 from the Port Ballast Main to Port BallastWater Pump P-5804A suction.

3 OPEN the Isolation Valve ZCV-104 and 145 on the Port Ballast Water PumpP-5804A Discharge to overboard.

4 OPEN the Isolation Valves ZCV-110 from the Starboard Ballast Main to Port BallastWater Pump P-5804C suction.

5 OPEN the Isolation Valve ZCV-111 and 146 on the Starboard Ballast Water PumpP-8504C Discharge to overboard.






Step Action

6 OPEN the Tank Valves ZCV-119 and ZCV-121 on the Port and Starboard No 2

WBTs respectively.

7 SET pump outputs to 5% then START Ballast Water Pumps P-5804A and P-5804C.ENSURE the level in the Port and Starboard No 2 WBTs is decreasing. ENSUREthat the levels in all other Ballast Tanks are not changing.

8 Record the time of commencement and the Ballast volume onboard at that time.Total ballast onboard from the Load Computer display will normally suffice.

9 Adjust the ballast pump speed to reduce the ballast at the correct rate to meet therequirement of the loading plan.

10 Monitor the surface of the sea around the overboard discharges at intervalsto ensure that any cargo or hydraulic oil leakage into the Ballast Tank is detected as

soon as possible.

11 Monitor hull criteria on the Load Computer during the transfer. List may developrapidly, particularly during the start and end of the de-ballast transfer. MAINTAIN theport and starboard tank levels approximately equal at all times by adjusting thespeed of the port or starboard pumps.

12 When required in the loading plan, OPEN the Tank Valves ZCV-127 and ZCV-129on the Port and Starboard No 4 WBTs respectively.

13 Open and close as required the tank suction valves on No 2 and No 4 WBTs tocontrol the de-ballasting from each tank at the correct rate to meet the requirementof the loading plan.

14 When No 2 WBT Port and Starboard are empty, CLOSE the tank valves ZCV-119and ZCV-121 on the Port and Starboard No 2 WBTs respectively.

15 ADJUST the ballast pump speed to control the de-ballasting from each tank at thecorrect rate to meet the requirement of the loading plan.

16 As further de-ballasting is required, OPEN the tank valves on the tanks to beemptied, ADJUSTING the rates for other tanks (via opening and closing theappropriate valves) already de-ballasting accordingly. This is necessary to maintainthe de-ballasting schedule in accordance with the loading plan simulation.

17 When the ballast operation is complete, SET pump outputs to zero, STOP andISOLATE the ballast pumps and CLOSE all WBT Tank valves.

18 Log the time of completion of ballast and record the Ballast Tank levels andvolumes.






PROCEDURE FOR DE-BALLASTING (SEMI-AUTOMATIC OPERATION)

Step Action

For this procedure it is assumed that de-ballasting will take place using ballastpumps P-5804A and C, initially from No 2 WBTs followed by No 4, No 3 and No 6P&S WBTs during the loading of the Group A Cargo Tanks. Only the 20in suctionvalves in each Ballast Tank are used during normal de-ballasting operations.

1 OPEN the Tank Valves ZCV-119 and ZCV-121, on the Port and Starboard No 2WBTs respectively.

2 On the DCS screen, SELECT the ‘de-ballasting’ button and SELECT the ‘sequence’button for pumps P-5804A and C. The associated valves will be opened(58-ZCV-103/145 and 58-ZCV-110/146) and provided all the interlock conditions aremet, the pump will be automatically started with pump output set to 5%.Once confirmation that the pump is operating (from the discharge line pressuretransmitter 58-PIT-103/109), the discharge valves (58-ZCV-104/111) will beautomatically opened to 5% initially, then the valve may be opened further from thevalve overlay on the DCS screen and the pump speed increased as required.

3 FOLLOW Steps 8 to 16 under De-ballasting (Manual Operation).

4 When the pumps are stopped from the DCS overlay, the starting sequence shall bereversed – stopping the pumps and then closing the isolation valves(58-ZCV-103/145 and 58-ZCV-110/146). If the sequence is manually overridden andthe pump is stopped, the valves will remain in the open position until closed by theoperator.

5 CLOSE all WBT tank valves and log the time of completion of Ballast and record the

Ballast tank levels and volumes.






PROCEDURE FOR BALLASTING (MANUAL OPERATION)

Step Action

1 When the requirement to increase ballast is identified in the loading plan, check onthe Load Computer that during the intended ballast changes the vessel is and willremain within permissible trim, stability and stress limits. For this procedure it isassumed that water ballast will be increased using ballast pumps P-5804A and C,initially filling No 3 and No 6 WBTs followed by No 4 P&S WBTs during theoffloading of the Group A Cargo Tanks. Only the 20in suction valves in each BallastTank are used during normal de-ballasting operations.

2 OPEN the Isolation Valves ZCV-101/102 from the sea chest to Port Ballast WaterPump P-5804A suction.

3 OPEN the Isolation Valve ZCV-104 and ZCV-149 on the Port Ballast Water PumpP-5804A. Discharge to the port ballast main.

4 OPEN the Isolation Valves ZCV-108/109 from the sea chest to Starboard BallastWater Pump P-5804C suction.

5 OPEN the Isolation Valve ZCV-111 and ZCV-150 on the Starboard Ballast WaterPump P-5804C Discharge to the Starboard Ballast Main.

6 OPEN the Tank Valves ZCV-123, ZCV-125, ZCV-135 and ZCV-137 on the Port andStarboard No 3 and No 6 WBTs respectively.

7 SET pump output to 5% and START Ballast Water Pump P-5804A and P-5804C.Bring pump speeds up to a maximum speed of 10% and ENSURE the level in thePort and Starboard No 3 and No 6 WBTs is increasing. Speed up the ballast pumpsto achieve the desired ballasting rate. ENSURE that the levels in all other BallastTanks are not changing.

8 Record the time of commencement and the Ballast volume onboard at that time.Total Ballast onboard from the Load Computer display will normally suffice.

9 Open and close as required the tank suction valves to reduce the ballast at thecorrect rate to meet the requirement of the loading plan.

10 Monitor hull criteria on the Load Computer during the transfer. List may developrapidly, particularly during the start and end of the De-ballast transfer. MAINTAINthe port and starboard tank levels approximately equal at all times by adjusting thespeed of the port or starboard pumps.

11 When required in the loading plan, OPEN the Tank Valves ZCV-127 and ZCV-129on the Port and Starboard No 4 WBTs respectively.

12 Adjust the tank valves on No 3, No 6 and No 4 WBTs to control the ballasting toeach tank at the correct rate to meet the requirement of the loading plan.

13 When No 3 and No 6 WBTs Port and Starboard are full, CLOSE the tank valvesZCV-123, ZCV-125, ZCV-135 and ZCV-137 on the Port and Starboard WBTsrespectively.

14 ADJUST the speed of the ballast pumps to control the ballasting of No 4 WBTs atthe correct rate to meet the requirement of the loading plan.






Step Action

15 As more ballast is required, OPEN the tank valves on the tanks to be filled,

ADJUSTING the rates for other tanks (via opening and closing the appropriatevalves) already receiving ballast accordingly. This is necessary to maintain theballast schedule in accordance with the loading plan.

16 When the ballast operation is complete, STOP and ISOLATE the ballast pumps andCLOSE all WBT Tank valves.

17 Log the time of completion of Ballast and record the Ballast tank levels and volumes.






PROCEDURE FOR BALLASTING (SEMI-AUTOMATIC OPERATION)

Step Action

1 For this procedure it is assumed that water ballast will be increased using ballastpumps P-5804A and C initially filling No 3 and No 6 WBTs followed by No 4 P&SWBTs during the offloading of the Group A Cargo Tanks. Only the 20in suctionvalves in each Ballast Tank are used during normal de-ballasting operations.

2 OPEN the Tank Valves ZCV-123, ZCV-125, ZCV-135 and ZCV-137 on the Port andStarboard No 3 and No 6 WBTs respectively.

3 On the DCS screen, SELECT the ‘ballasting’ button and SELECT the ‘sequence’button for pumps P-5804A and C. The associated valves will be opened(58-ZCV-101/102/149 and ZCV-108/109/150) and provided all the interlockconditions are met, the pump will be automatically started to 5%. Once confirmationthat the pump is operating (from the discharge line pressure transmitter58-PIT-103/109), the discharge valves (58-ZCV-104/111) will automatically beopened, initially to 5%, then the valve may be opened further from the valve overlayon the DCS screen as required and the pumps speeded to meet the demand.

4 FOLLOW Steps 8 to 15 under Ballasting (Manual Operation).

5 When the pumps are stopped from the DCS overlay, the starting sequence shall bereversed – stopping the pumps and then closing the isolation valves(58-ZCV-101/102/104/149 and 58-ZCV-108/109/111/150). If the sequence ismanually overridden and the pump is stopped, the valves shall remain in the openposition until closed by the operator.

6 CLOSE all WBT Tank valves, log the time of completion of Ballast and record the

Ballast tank levels and volumes.






PROCEDURE FOR BALLAST LINE FLOODINGBoth the port and starboard ballast lines are fitted with capacitance level probes near theforward and aft ends of the lines (58-LZT-133/34/35/36). These are to give an indication if theballast line in its vicinity is flooded. On sensing a non-flooded condition (pipe less than

90% full) on any of the sensors, an alarm will be raised in the DCS. Re-flooding of the ballastline will normally be sequenced automatically from the DCS.

If any ballast pump is running and the above condition occurs, the stopping of the pump(s)and closing of the tank isolation valves will be delayed for a configurable time (0 to60 seconds initially set at 10). The DCS programme will also prevent the opening of anyfurther valves (except those mentioned below) and pumps from starting until the non-floodedcondition is reset. This is to allow adequate stripping of any tank (when stripping a tank someair is likely to be sucked into the main header after the water level falls below the bottom ofthe suction pipe). Manual closing of the valves is not affected. This sequence and interlockswill operate irrespective of the selection of the ‘Manual Override’.

The ballast line will be flooded by gravity filling through the following valves: ZCV-101/108,

ZCV-102/112 (limited to 5% open), ZCV-103/113, ZCV-147/148, ZCV-141/142 and ZCV-151.These valves will be permitted to open either under sequence control or manually while thelow level in the ballast lines exists.

Step Action

1 To ‘re-flood’ the system, PRESS the ‘flooding’ button which will automatically openthe following valves in this sequence (the pumps must be confirmed as stopped):

• 58-ZCV-151 – Ballast line vent

•

58-ZCV-141/142 – Forward ringmain isolation valves• 58-ZCV-147/148 – Middle ringmain isolation valves

• 58-ZCV-103/113 – Pump A/D ballast lines suction

• 58-ZCV-102/112 – Pump A/D sea suction (proportional to 5%)