tge gas engineering · rev1_2020 page 2 the cycle of process safety design typical safety systems...

www.tge-gas.com Rev1_2020

TGE GAS ENGINEERING

LIQUEFIED GAS TERMINALS

DESIGNED WITH SAFETY AT HEART


▪ The cycle of process safety design

▪ Typical safety systems in a cryogenic gas terminal

▪ Marine installations & Transfer System

▪ Storage Tank

▪ Sendout Systems

▪ Fire Protection

▪ Conclusions

OUTLINE


THE LIFE CYCLE OF PROCESS SAFETY DESIGN

HAZARDS

Identify• HAZID

• HAZOP

Analyse / Understand• Consequence Modelling

• Fire Hazards Assessment

• Quantitative Risk

Assessment (QRA) Control• Process Control

• Alarms

• Safety Instrumented Functions

→ SIL Assessment

Mitigate• Fire, Gas & Spill Detection System

• Control of Ignition Sources-

Hazardous Area Classification

• Spill Collection

• Fire Fighting System

• Passive fire and cold embrittlement

Protection


A TYPICAL IMPORT TERMINAL

Reganosa LNG Terminal. Spain


MARINE INSTALLATIONS

• Hazards

• Ship collision

• Releases on water → large flammable

clouds, pool fire, RPT

• Shared jetties, handling different products

• International crews → Human Factors

• Control / Mitigation

• Port traffic control

• Ship-to-shore link

• Powered Emergency Release

Couplings (PERC)

• Emergency Shutdown system (ESD)

• Impounding basinReganosa LNG Terminal. Spain


TRANSFER SYSTEM

• Long pipeline (can be a few km)

• Usually kept liquid full with recirculation

• Allows quick start-up

• Avoids formation of vapour pockets

• Risk of hydraulic pressure surge (e.g. in

case of emergency shutdown (ESD)

• Transient surge analysis to ensure inherently

safe pipeline and supports design.

• Risk of trapped cryogenic liquid

• Thermal Safety Valves (TSV)

• TSV discharge to the tank to avoid flaring

Vystok LNG Terminal. Russia


STORAGE TANK

• Very large inventory of liquefied gas

• Several tank designs:

• Single containment

• Double containment

• Full containment

• Steel outer wall

• Concrete outer wall

• In-tank pumps

• Often large, multi-level tank-top platforms

Grangemouth Ethane Tank, UK.


STORAGE TANK HAZARDS

SINES LNG Terminal

• Overpressure / Vacuum

• Overfilling

• Rollover (LNG)

• Leaks from pump head flanges

• Gas detection difficult due to high winds at tank top

• Jet Fire

• Short duration after pump stops

• Pool fire

• Pool formation avoided by sloping/ drainage to

downcomer and impounding basin.

• Ignited PSV Release


SEND-OUT SYSTEM

• Liquid send-out

• Truck loading

• Ship / barge loading

• Bunkering (LNG)

• Railcar loading

• Gaseous send-out

• To local low / high pressure mains pipeline


HAZARDS ASSOCIATED WITH TRUCK LOADING

• Human Factors

• Manual or automatic control systems?

• Operation by truck driver / terminal

personnel ?

• Interface between terminal & truck

• Different truck designs

• Overfilling & overpressure protection-

ensured by terminal and truck systems.

• Frequent connection/ disconnection

• Hard arms or flexible hoses?

• High potential for leaks

• Many loading bays → congested area

OX Ethylene Terminal, China


• Submerged Combustion Vaporisers

(SCV)

• Open Rack Vaporisers (ORV)

• Ambient Air Vaporisers (AAV)

• Intermediate Fluid Vaporisers

• Other …

GAS SEND-OUT SYSTEM

The choice of re-gasification system depends on fluid to be gasified, location,

ambient conditions and availability of heat transfer fluid.

ORV. Reganosa LNG Terminal. Spain


• High pressure pumps to meet required pipeline pressure• Potential for large, high pressure liquid releases• High pressure 2-phase / gas jet fires

HAZARDS ASSOCIATED WITH GAS SEND-OUT SYSTEM

• Design pressure (DP) of external mains pipeline

• Terminal piping able to withstand maximum pump shut-off pressure, but no control over design of external pipeline.

• High Integrity Pressure Protection System (HIPPS) might be required

• Material selection downstream of vaporiser• Cryogenic lines usually stainless steel. Gas pipeline usually carbon steel• Need to protect from liquid breakthrough - how far from vaporiser?• Reliance on Safety Instrumented Systems

• Vaporisers can create large congested areas (specially for AAV)


FIRE & COLD EMBRITTLEMENT PROTECTION

• Fire Hazard Assessment (FHA) identifies

equipment and structures to be protected

• Main objective: minimise the risk of escalation

• Informs the selection of:

• Fire, gas and spill detection systems

• Need for automatic ESD

• Passive Fire Protection (PFP)

• Active fire protection

• Embrittlement protection – avoid contact of

critical steel structures with cryogenic fluids.Shenzen LNG Terminal. China


ACTIVE FIRE PROTECTION

• Best fire fighting is to remove the fuel

• Rapid isolation and shut-down.

• Minimise inventories

• Water cooling of equipment and structures subjected to high

thermal loads.

• Contain spills in impounding basins.

• Reduce dispersion & thermal radiation by using foam/foam blocks.

Shenzen LNG Terminal. China

OX Ethylene Terminal, China


The safe design of a liquefied gas terminal requires a multidisciplinary approach

between process safety, process design, plant design, structural and

instrumentation engineers.

This can achieve a design that offers maximum reliability, operability and safety.

CONCLUSION


Thank you for your attention!


Is there a real need for a impounding basin to collect spills

from full containment LNG tanks? Considering that:

▪In-tank pumps in vertical columns

▪Piping is largely welded after the pump head flange

Q & A


LINKEDIN@TGE Gas Engineering

TWITTER@TGE_Gas

YOUTUBE@TGE Gas Engineering

CONTACT Karina.AlmeidaLeñero

@tge-gas.com

tge gas engineering · rev1_2020 page 2 the cycle of process safety design typical safety systems...

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