construction competition specification

8/17/2019 Construction Competition Specification

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CONFORMED COPY

OF THE PRINCIPAL CONTRACT DATED 31ST

MARCH 2003

AND THE AMENDMENTS TO THE PRINCIPAL CONTRACT

PURSUANT TO THE DEED OF AMENDMENT DATED 28TH

MAY 2003

SCHEDULE 43

CONSTRUCTION COMPETITION SPECIFICATION

Energy from Waste – Technical Specification

Part 1

Specification – Electricity and Heat Recovery Facility

This specification covers the main design requirements for the Energy from Waste Plant

principally relating to the systems and facilities.

The main contents are:

• Performance and Operation Requirements

• Architectural Concept and Drawings

• Combustion Process, Boiler and HP Pipework

• Steam Turbine, Generator and Associated Steam Systems

•

Flue Gas Treatment Equipment, Ash and Metal Separation• Electrical Systems

• Instrumentation and Control

• Distributed Control System

• Other Facilities

• Civil Engineering and Building

• Detailed Civil Engineering Specification

• Construction Requirements

Part 2

Specification – Civil Engineering and Building Specification

This part of the specification covers the building works, fabric of the building and services. It

details the minimum acceptable standards and includes principally the following:

• Mechanical Services

• Electrical Services

• Excavations

• Structural Steelwork

• Fixtures and Fittings

• Civil and Building Works

Schedule 43 Page 1 of 1


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Purchaser EFW Contract

SPECIFICATION:

ELECTRICITY and HEAT RECOVERY FACILITY

EAST SUSSEX AND BRIGHTON & HOVE CITY COUNCIL

ESCC/B&HRev1 1 Specification


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Contents

1 Introduction

1.1 General1.2 Design Philosophy1.3 Scope of Work and Services supplied by the Contractor1.4 Performance Requirements1.5 Operational Requirements

2. Detailed Technical Requirements

2.1 Architectural Concept and Drawings2.2 Access, Tipping and Waste Handling Facilities2.3 Combustion Process, Boiler and HP Pipework2.4 Steam Turbine, Generator and Associated Steam Systems2.5 Flue Gas Treatment Equipment, Ash and Metal Separation2.6 Electrical Systems2.7 Instrumentation and Control2.8 Distributed Control System2.9 Other Facilities2.10 Civil Engineering and Building

2.11 Detailed Civil Engineering Specification

3. Construction Requirements

3.1 Design and Construction3.2 The Site3.3 Regulatory Requirements3.4 Health and Safety3.5 Project Documentation3.6 Spares and Warranties

Appendix A Weighbridge SpecificationAppendix B MassBalance, Energy Balance,

Service Life Schedule,and Data Sheets

Appendix C Architectural Concept DrawingsGlossary of Terms

ESCCBH_EFWSpec_Rev1.doc 2 Specification


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1. INTRODUCTION

1.1 GENERAL

The Intent and spirit of the Contract is to provide for the Works herein specified within the

Contract dates and Contract Price, in every detail for the purpose designed and it is herebyunderstood that the Contractor, in accepting the Contract, agrees to furnish everythingnecessary for such purpose notwithstanding any omission in the drawings or specifications.

The Contractor shall prepare a detailed Project Quality Plan, which shall be subject to approvalby the Purchaser. The Project Quality Plan shall detail, but not be limited to, the following: thedesign, construction, manufacture, welding, inspection, testing, installation and commissioningof all items within the Works.

The Contractor shall comply with all elements of this Specification and deviations or variationsfrom this Specification shall only be permitted with the written approval of the Purchaser.

The Contractor shall comply with the conditions of the Site Lease, the Environmental Protection Act 1990, the Waste Incineration Directive and all other Statutory Legislation.

Onyx intends to build a new Energy from Waste Plant at the following preferred site subject togranting of planning permission and at the following base capacity:

• Newhaven, North Quay 1 x 28 tonnes per hour

The Plant will form part of an integrated waste management scheme.

The Plant shall be designed to burn municipal solid waste. The plant shall be designed tomaximise the quantity of electricity generated, and subject to confirmation by the Purchaser, aquantity of heat exported to a District Heating Network yet to be identified.

The plant design shall allow the possibility to install, in the future, a second incineration line ina parallel configuration. The Contractor shall take special care on this point and shall not installheavy equipment on this provisional additional plant location without the approval of thePurchaser.

This Specification covers the main design requirements for the Energy from Waste Plant.



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1.2 DESIGN PHILOSOPHY

The Plant shall be designed for a service life of at least 25 years from Takeover.

The Contractor shall organise the following meetings with attendance by representatives from

the Purchaser and the Project Manager:

• HAZOP Reviews

• Main Purchase Order Meetings

• Design Reviews

The Plant shall comply with the standards in the following order of precedence:1. Standards referenced in this Specification2. British Standards and British and UK Codes of Practice3. Alternative Standards proposed by the Contractor which shall be approved in writingby the Purchaser.

Adherence to the applicable standards shall not be confined to the manufacture of equipmentand civil works but also extend to the regulations governing the construction andcommissioning of the Plant and include, but not be limited to, the following:

• Management of Health and Safety at Work Regulations

• Manual Handling Regulations

• Management Regulations

• Reporting of Injuries Diseases and Dangerous Occurrences Regulations (RIDDOR) 1995

• Construction (Design and Management) Regulations (CDM)

• The Workplace Health and Safety Welfare

• The Workplace Equipment Regulations• Site Noise Requirements

• Building Control Requirements

• Fire Codes

• COSHH Regulations

• The Construction (Health and Safety and Welfare) Regulations 1996

All phases of the Works shall comply with the relevant terms of the Planning Permission.

The Contractor shall be appointed as "Principal Contractor" in compliance with the CDMRegulations.



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1.3 SCOPE OF WORK AND SERVICES SUPPLIED BY THE CONTRACTOR

The Contractor shall be completely responsible for the site preparation, the design,manufacture, supply, works testing, transportation, delivery to site, unloading at site,construction, painting, commissioning and putting into commercial operation, and testing for

performance and reliability up to and after Takeover of the new Plant comprising, but not limitedto, the following basic elements:

• Presentation of a project as defined in this Specification and the Tender requirements.

• The complete execution of the works allowing the Acceptance by the Purchaser of a“turnkey” type installation in full working condition and including the installation at theworksite, the supply and transport to the worksite of all necessary materials and equipment,together with their implementation or assembly, and namely:

The installations for the reception and handling of waste materials: weighbridges, tippinghall and waste handling area, overhead cranes and grabs.

Incinerator furnace, waste heat boiler, the condensing turbogenerator, and air-cooledcondensers together with all required ancillary equipment.Installations and equipment for the extraction, evacuation and storage of residues.Gas treatment and purification systems including coolers, dust extractors, induceddraught fan as well as a chimney for the removal and dispersion of flue gases.Installations and equipment for the extraction, evacuation, storage and packaging of fluegas treatment and purification residuesControl System.Boiler Water Treatment Plant and Laboratory.Fire Tank and Pumps and associated Fire Systems to NFPA requirements.Transformer and Switchgear.LV Transformers and Switchgear.Standby Electrical Supply.Plant and Instrument Air.Export/import Connection to 33kV metering circuit breaker and Onsite Compound.UPS. Air conditioning of electrical rooms, control room, management offices and conferenceroom.Mechanical Ventilation Systems for technical rooms.Natural Ventilation system for boiler hall.Fuel Tanks and Delivery Systems (subject to the re-use provisions in 1.1).Site Circulation Roadways and Entrance/Exit Roadways and Ramps.Management Offices, Amenity Facilities, Mess, Washing and Changing Facilities.

• The loading diagrams and plans, foundation plans, equipment and civil works andassociated guidelines

• The file of works completed, the starting-up of the installation, and the tests carried outduring works and performance tests

• The remuneration for the services in particular includes: contract management of a “turnkey”type principal installations contract, co-ordination of works with sub-contractors, the start-up,maintenance and operating costs of all provisional construction works necessary forcompletion of the works

• All design costs

• All ancillary costs arising from materials acceptance testing and inspections and all checks,including the review of works plans as per Building Regulations and other regulations and

including pressurised appliances, handling equipment, electrical installations, etc• List of spare parts for two years



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• Expenses related to functional tests of equipment (3rd party tests will only be required to theextent required by law, codes and statutes)

• All cost of lighting, signposting and marking for the site, the equipment and materials stores

• All patent costs

• All costs resulting from the supply and installation of those protective devices required by lawincluding works legislation

• All taxes and duties together with Contractor profits, but excluding value added tax (VAT)• Responsibility for the organisation of traffic, cleanliness of roads, equipment deliveries in

relation to the Contractor’s activities.

• Burdens resulting from the provisions required to observe building site regulations

• The works which the Contractor may be required to undertake to ensure that the Works arecompleted satisfactorily.

• The initial provisions of consumables such as oils, greases, printer paper, listing paper, etc

• The implementation of road and utilities connections .

• The supply and installation of a worksite notice board giving notice of the nature of the

works, the Purchaser, the Project Engineer, and Control and Monitoring Company(ies), theContractor and all Sub-Contractors

• The supply in sufficient number of all documents necessary for the Works

• The application for and receipt of Building Regulations approval

• The construction of the Plant in accordance with the Planning Authority, the Environment Agency and Statutory and Regulatory Authorities

• The installation and withdrawal of equipment from the Site and laydown areas, uponcompletion of the Works.

• Sound attenuation protection to equipment in all technical rooms and to meet the noise limitsidentified in Schedule 7

• Contractors personnel during commissioning

• Consumables and utilities during commissioning

• Connection to the existing water supply

The Plant shall be capable of achieving the requirements, levels and standards of performanceset out in this document. The Contractor shall provide all the necessary operation materials,lubricants, chemicals, raw materials, consumables and fuel other than municipal waste up tothe time of Takeover.

The Contractor shall be responsible for providing the Purchaser with all special tools requiredfor maintenance and repair of the Plant, and in particular, but not limited to, a mobile bridge toaccess the furnace during maintenance periods,and provision for a suspended platform for inspection of inconel cladding. In general, provision

shall be made for access where this is required every 6 months or more frequently.

The Plant layout shall be chosen to ensure that waste combustion takes place in the bestpossible conditions of hygiene, safety and efficiency. The general layout, the choice ofequipment, centralisation of control and monitoring devices, simple and rational automationshall all be considered in order to maximise operational efficiency, optimise personnelrequirements and avoid contact with the waste brought to the plant. The plant shall be designedsuch that the boiler, FGT residue and bottom ash extraction and loading areas are not recessedbelow floor level to enable clear access for forklift and other vehicles from site ingress andegress levels.

All requirements specified in this document shall be adhered to by the Contractor unless

specifically exempted and agreed in writing by the Purchaser.

The Contract Price shall exclude revenues derived from electricity sales, and waste gate fees



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derived prior to Takeover.



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1.4 PLANT PERFORMANCE

The Contractor shall design the plant for a 30 year operating life.

This shall be achieved by use of the appropriate design parameters, codes, standards andspecifications and the selection of suitable equipment, materials and methods of construction.

The Plant shall be designed to process Acceptable Combustible Waste which will comprise, thefollowing waste types:

• Unsorted waste including items up to 900mm by 700mm by 700mm in size and notexceeding 250kg in weight in the following categories:-Collected Household Waste and Commercial Waste (excluding loads of Commercial

that is inert in nature)-Grey Waste and Waste that is of a confidential nature (in either case where suitable for

combustion)• Combustible Waste shall include Collected Waste after the removal of Collected Dry

Recyclables, Biowaste and/or Green Garden Waste.

• Solid household waste: such as rubbish and refuse normally collected and disposed ofby residential households and commercial, institutional or industrial establishmentswhich may comprise: leaves, twigs, glass, metals and other constituents that normallyappear in household refuse and, certain wastes which are difficult to process such asleather or automotive waste when mixed with other Acceptable Wastes

• Solid combustible waste arising from segregated HWRC waste

• Solid industrial waste, in so far as it is of similar composition of household waste

• Any of the above waste, after storage in bales

•

All the above waste types may be delivered to Plant. The Plant shall be designed to burn all ofthese waste types.

The following waste shall not be considered as Acceptable Waste:

• sewage sludge, spoils, screenings, debris from waste water treatment plants

• rubble and materials rejected from rubble sorting

• waste liquids or bulk liquids from industrial processes or commercial premises

• Infectious wastes or human or animal body parts from hospitals or clinics, wastes fromslaughterhouses and special wastes which cannot be treated by the same means asmunicipal waste without risks to people or environment because of their flammability,

toxicity, corrosivity or explosiveness.



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The Plant shall meet the following design conditions:

Site Newhaven – North Quay

Design capacity based on 8000 hrs 220.000 tpa

Plant Design Capacity (MCR) 28 tphr

Design Waste Net Calorific Value(MCR)

9.2 MJ/kg

Waste LCV range **MJ/kg

Base Stream Arrangement single stream 1 x 28 tphr

Export/Import connection and voltage 33kV connection provided by Purchaser.

Water Supply Existing Towns water supply

Cooling Supply Air Condenser at 10°C reference temperature

Demolition Existing amenities and clinical incinerator to bedemolished

11kV Standby Supply Not Used

Weighbridge Automated to allow control from plant controlroom and local cabin 1 x entry

1 x exit

Crane/Grab 2 sets of equipment

The Contractor has been invited to assess the calorific value of the Acceptable Waste andestimate what parameters should be used.

The Contractor shall identify the effect and bottlenecks of operating the plant at the designwaste throughput but with a waste calorific value of 110% of design. The effects on the eachelement of the process: furnace, boiler, steam plant, flue gas treatment equipment shall bedocumented.

The steam turbine shall have the provision for a steam takeoff flange that shall be used toprovide steam for the district heating. The Contractor shall ensure that adequate provision andspace is provided in the Plant layout to enable district heating equipment, exchangers andpipework to be installed. The layout shall be reviewed by the Purchaser. The Contractor shallprovide in the form of a graph, the quantity and temperature of the maximum district heatingload that can be accommodated and the resultant reduction in exported electricity.

Mass Balances, Heat Balances, Service Life Schedule, and Data Sheets are contained in Appendix B.

Noise level studies shall be carried out on the following elements to ensure adherence to theguarantee levels detailed in Schedule 7:

-turbogenerator-bottom ash ferrous metal separator and large item separator-turbogenerator oil cooling system

-fluestack-fans-transformers



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-boiler water feed and condensate pumps-overhead cranes-air compressors-soundproofing to the turbogenerator room-soundproofing to technical rooms defined as the following: workshops, laboratory,stores, water treatment room, pump rooms, compressor rooms, electrical and

instrument rooms-soundproofing to the offices and control rooms

ESCCBH_EFWSpec_Rev1.doc 10Specification


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1.5 OPERATIONAL REQUIREMENTS

The Plant shall operate 24 hours per day, 7 days a week all year round except for plannedoutages and be designed for the minimum of downtime. The Plants shall be designed tomaximise electricity or heat export at 100% MCR.

The tipping hall and waste handling equipment shall be designed to function as a transferstation. Therefore the area and equipment shall be designed to enable bunker waste to bebackloaded into articulated vehicles in the event of extended maintenance and.

The Contractor shall design the Plant and associated facilities to take account of therequirements of the staff levels required for operation and maintenance , weighbridge,clerical/admin and plant management .

The Plant shall be automated sufficiently to enable a two person operator shift staff to operatethe Plant.

The two waste cranes shall be designed to operate simultaneously.

The Plant shall be designed to operate for extended periods at 100% MCR in island mode withsteam dumped to the condensers with an ambient temperature of up to 30ºC. Suitable noisesuppression shall be allowed in the design of the Plant to ensure that the noise level at the siteboundary is in accordance with the requirements in Schedule 7.

Load rejection testing shall confirm the turbogenerator operation is stable when going from fullloading to island mode.

The Plant shall also be designed with an emergency generator sufficient to safely shut downthe plant.

All metering, associated equipment and protection systems shall be designed to meet therequirements of:

• G59/1: Recommendations for connection and protection settings for embeddedgenerating plants


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2. DETAILED TECHNICAL REQUIREMENTS

2.1 ARCHITECTURAL CONCEPT

The Purchaser includes Architectural Concept Drawings prepared by Purchaser’s Consultant

which are to be used by the Contractor to develop the detailed design and these are containedin Appendix C. For the avoidance of doubt, the Contractor shall comply with the requirementsand concepts in the drawings and shall be solely responsible for the detailed design of the Plantand no deviations or claims or variations will be considered by the Purchaser in this respect.The Contractor is permitted to propose modifications as agreed in writing with the Purchaser.

The Contractor shall be responsible for the detailed design of the Plant.

2.2 ACCESS, TIPPING AND WASTE HANDLING FACILITIES

2.2.1 Plant Access

The following vehicular access shall be provided to the Plant:• Tipping hall for waste deliveries• Bottom Ash and FGT Residue collection vehicles• Vehicle access for maintenance purposes• Vehicle access for reagent and consumables deliveries• Vehicle access to staff parking areas• Allocated parking spaces for 2 Articulated Trailers

Acceptable combustible waste shall be delivered to the site by the Purchaser.

The Plant storage areas shall segregate the dirty and dusty bottom ash and ferrous storage

bays. Wheel wash facilities shall be provided for all site vehicles to ensure clean and dirty areasand bays are contained. In addition a fuelling area shall be provided for off-road and sitevehicles.

The Contractor shall ensure that the layout of the plant and equipment enables forklift access toall necessary areas.

2.2.2 Weighbridge and weighing software

A computerised weighing facility shall be provided which complies with the requirements of TheEnvironmental Protection (Duty of Care) Regulations 1996 and Customs and ExciseRequirements. The equipment shall record and issue waste transfer tickets with the followingdetails: tare weight, gross weight, net weight, waste type, carrier, vehicle registration, vehicletype, etc and as required by the Principal Contract with East Sussex County Council andBrighton & Hove City Council.

Two 18 metre weighbridges shall be provided, one on incoming and one on outgoing roadways.The following equipment shall be provided: barrier induction loops, traffic lights, weighingterminal including: weatherproof casing, electrical heater, digital display, tag reader, ticketprinter, entrance and exit barriers, two way intercom system. Vehicle identification shall beachieved using radio frequency/proximity tags. These tags shall have been used in similarsituations.

An automatic weighing system which interfaces with the Sabre 8000 shall be installedcomprise the following: one digital weight indicator, one complete Pentium Windows based



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computer , one printer for summaries/reports, one floppy disc reader/writer for data saving,hardware, twin weighbridge computer input screens, CCTV of weighbridge. A modem link shallbe installed to enable weighbridge information to be transferred to other Purchaser facilities.The weighbridges shall be preferably visible from the CCR and CCTV of front and rear of theweighbridge shall be provided in all cases. Audiovisual communication shall be providedbetween the weighbridge and the CCR. Typical weighbridge details are found in Appendix A.

In addition to the weighbridge administration facilities with the CCR, a duplicate automaticweighbridge system shall be installed at the weighbridge administration/security gatehousewhich is provided with additional weighbridge inputing facilities and site cameras and displaymonitors. This weighbridge/security gatehouse shall have the following facilities: an office and atoilet with washbasin, heating and lighting and 240V mains.

Weighbridge electrical supplies shall be taken from the emergency distribution board.

2.2.3 Tipping Hall

The hall shall be installed with electrically operated incoming and outgoing sliding doors with aheight clearance of 8 metres and capable of being controlled remotely from the CCR andlocally. The Contractor shall provide details of the doors for review by the Purchaser.

Air for combustion shall be drawn through the building to minimise odours. The shutter doorsshall be capable of withstanding air pressure loading when closed.

The tipping hall shall have unloading bays for acceptable combustible waste.

The turning area and unloading bays shall be suitable for the unloading vehicles commonlyused for the transportation of waste such as, but not limited to, the following:

-Conventional Refuse Collection Vehicles (RCV)-80m³ articulated vehicles-Walking floor type transfer station vehicles-Rolonofs tipping and drag type-Commercial waste in containers and skips with allowance for hook lift-Compactor trailers

The Contractor shall provide large enough tipping hall for the waste capacity of the Plant and toensure vehicle turnaround is as fast as possible.

Traffic lights shall be provided to control traffic flows and avoid congestion. Particular attentionshould be paid to avoidance of queuing on the ramp and associated roadways.

Unloading bays shall be provided with bollards and raised kerbs to enable vehicles to reversesafely. The raised kerbs shall have a notch to allow waste to be brushed back into the bunker.Red/green lights shall be installed to indicate which bays are operational and designed to beclearly seen by reversing vehicles. Any structural steel columns shall be protected from fire andfrom damage from refuse vehicles in the tipping hall and from crane/grab movements in thebunker. The Contractor shall provide Armco or equivalent to all other areas where damage isexpected. Water floor wash facilities shall be provided around the feedchutes.

The tipping area shall have a power floated hardened concrete surface to accommodate frontloading shovel activities at unloading bays.

The tipping hall shall be well lit to enable efficient delivery operations to take place.



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Pushwalls shall be provided as indicated on the pushwall drawings in section 2.11 Detailed CivilEngineering Specification.

2.2.4 Waste Bunker

The fully enclosed waste bunker shall include a solid concrete wall directly above the raised

curb between the tipping hall and the bunker areas (as constructed at SELCHP) and shall bedesigned to provide 3 day storage as a minimum at normal waste discharge level withoutstacking. Further capacity shall be accommodated by readily stacking waste above the vehicleunloading level, without it emerging from the bunker. Waste delivery vehicles shall offloadwaste from one side of the bunker. The bunker width shall be at least twice the maximumdiameter of the grab. The bunker shall be designed and constructed as an “aqueous liquidretaining structure” to BS 8007.

The bunker and structure directly above shall be designed with no horizontal shelves andledges to avoid dusts and refuse collecting.

The Contractor shall provide smoke vents in the bunker area. Roof vents/louvres shall bedesigned for a maximum differential temperature of 10°C between inside and outsideconditions.

2.2.5 Travelling Crane and Grab

Travelling CraneEach crane and grab shall be designed to transfer the Plant’s daily waste capacity into the feedhopper in a 16-hour period. In addition, the crane and grab shall be capable of furthercontinuous operation for the remaining 8 hours of the day for lifting, moving, mixing, casting and

stacking waste in the storage bunker. Continuous operation of each crane shall be clearlydemonstrated and tested during the Reliability Testing Period prior to Takeover. Two identicaltravelling cranes shall be supplied, designed for heavy duty class incorporating well provenfeatures developed especially for waste grabbing duty ensuring continuous highly reliableservice and availability in a dusty atmosphere. The capacity of the grab shall be based on amaximum of 30 grab loadings per hour during the 16-hour period. The crane controls andrelays shall be located in a control panel near the crane laydown area/tipping hall.

The Contractor shall ensure that a suitable crane and grab parking and laydown area isprovided and that either of the cranes can continue to feed the hopper while the other crane isundergoing maintenance.

The travelling crane and grab shall meet BS 466 and BS 2573 latest editions as a minimumwith the highest classifications:

Crane as a whole - A8

Class utilisation - U8Group Class - Q4

Mechanism Classification.Hoist - M8Bridge - M7

Trolley - M7State of Loading - L4Class of utilisation - T8



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The travelling crane of a double beam type resting on 4 wheels, two of which are driven. Eachdriven wheel is actuated by one geared motor-brake unit. Anti-collision devices shall beprovided for safe operation. A maintenance gantry and access way on both sides shall beprovided on each crane together with anti-personnel limit switches. All crane travel limitswitches and drives shall have visual indication of being tripped out.

The crane shall be capable of manual, semi-automatic and fully automatic operation. The craneoperator shall be able to direct and discharge the grab automatically into predetermined feedhopper positions once the grab is loaded (semi-automatic function).

The crane shall be complete in all respects including software, instrumentation and mechanicalequipment.

The crane operator station shall allow clear unimpaired vision of the waste bunker and visiondirectly below the operator station. The crane operator station shall be incorporated into theCentral Control Room. The crane operator station glass panel shall have 2 hour fire protectionthrough water spray and/or fireglass. The glass windows shall be designed to enable the

manual cleaning of both sides of the window from within the crane operator station. The feedhoppers shall be monitored by colour CCTV cameras and displayed in the crane cabin. Eachcrane shall be designed to have access to all areas of the waste bunker. Two of the officesdetailed in section 2.10.20 shall be provided adjacent or on the same floor as the CCR..

The crane operators’ chair shall be ergonomically designed and capable of swivelling to allorientations necessary. It shall enable the chair to be replaced easily without the removal of thecontrol harness. Traffic lights and management systems shall be duplicated on each craneoperator control console.

The hoisting ropes shall be specified to be widely spread between the trolley anchorage anddrum mounting position. This is to attain the widest possible rope fleet angle to improve the

crane's resistance to grab spinning. The hoist drum grooving shall be specified to be surfacehardened to 500 Brinnell Hardness and optimised with rope material hardness to produce asatisfactory life for the drum and so as not to cause excessive rope wear. These features shallensure long life and lower stress fatigue induced by arduous continuous grabbing activity.Special features including limit switches shall also be incorporated to prevent ropes doublewinding and fouling on the drum. The grab shall be connected to the crane block with hightensile bolting.

The Grab

The electrical connection between the crane and the grab shall be hard wired without socketsand be highly durable and well proven.

The layout of the cranes shall allow for the effective maintenance of each crane grab. Asdetailed in figure 1, the maintenance area shall allow for the grab to be lowered to ground levelfor transportation to the appropriate laydown area or off-site.

The crane grab shall be capable of simultaneous operation in two directions in the horizontalplane whilst operation raising and lowering the grab in the vertical plane. Semi-automaticcontrol of the crane shall be provided which includes combined motions of the crane tominimise grab swing. The Contractor shall ensure the safe segregation of the two operationalcranes. The grab shall be fitted with visual indication of being tripped out.

A load cell based weighing system for the grab shall be provided to enable the operator torecord the weight of each grab load before discharge into the feed chute. The weighing systemshall have an accuracy better than 2.5% and be displayed in the crane operator station and



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connected to the DCS.

2.2.6 Feed Hopper

The dimensions of the hopper shall be greater than those of the grab when fully open andsufficient clearance shall be provided around the grab during feeding operations.

The feed hopper shall be designed to avoid jamming. In the event of a jam, there needs to beeasy access to remove the obstruction. Lifting beams and electric winches shall be fitted aboveeach loading hopper to enable the removal of blockages from the furnace feed mechanism. Thelifting beam shall be rated at SWL 2 tonne minimum.

The feed hopper perimeter shall be surrounded by 1.1m high above floor level solid balustradeat least 150mm thick on three sides to allow access for manual stroking in the event that thehopper becomes obstructed by bulky waste. All other edges to the upper feed hopper floor areashall be fitted with 1.1m high above floor level heavy duty steel railings of 150mmdiameter/concrete balustrades at least 150mm thick to act as physical and safety protection forpersonnel as regular access in this area is required.

Sufficient access hatches, fitted with a handling system to enable easy opening and closureand grab laydown areas shall be provided to enable both grabs to be transported to tipping halllevel. A general arrangement showing the balustrades and the overall arrangement shall besubmitted to the Purchaser for approval.

Efficient hoists and lift systems shall be provided for maintenance of the crane and grabbetween hopper floor level and tipping hall level.

A back-loading hopper shall be provided by the Contractor. Access to MaintenanceHatch and GrabLaydown Area

Feed hopperBunker So15

lid balustrade0mm thick Heavy duty steel orconcrete railings at

least 150mm thick

Hopper to enablebackloading of waste

to bulker vehicle below



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2.3 COMBUSTION PROCESS, BOILER AND HP STEAM PIPEWORK

The Contractor shall provide a furnace with the ability to combust fuel without leading toexcessive slagging or fouling and with an online cleaning system such as rappers andsootblowers (either semi or fully retractable type). If sootblowers are fitted, they shall operate

intermittently and be designed not to reduce Plant net electrical output by more than 1.0%.

The Contractor shall design the plant in all respects to operate at 6% O 2 and to meet theperformance improvements at 6% O2.

The current guarantees in Schedule 7 paragraph 7.4.2 are based on 7.5% oxygen levels and inthe event of favourable experience gained from operation at lower oxygen set points at otherPlants operated by the Contractor, the Contractor shall link these improvements in theguarantees of performance, efficiency, plant lifetimes and electricity generated in line with anyreduction in the oxygen set point.

2.3.1 Moving Grate

The moving grate shall be suitable for the combustion of all wastes identified in Section 1. Aswith the design of the whole Plant, the grate shall be designed to operate safely and efficientlyover a 30-year design life with minimal maintenance. Residence times shall meet therequirements specified in section 1.4.

The grate shall consist of reciprocating bars slowly stirring and mixing the waste in order to givegood mixing, combustion and flame position control. The stroke of bars shall be adjustable. Thegrate bars shall be designed to be self-cleaning and avoid the build up of clinker residue. The

grate shall give consistently good performance with a wide range of waste types and have along trouble-free life. The Contractor shall provide data on the grate life and operatingtemperatures and give details and full costs of spares and equipment required over the designlife.

The grate shall be designed to accept possible future water cooling, in case of LCV increase.

The Contractor shall be responsible for designing effective combustion and airflows through thefurnace. Combined primary air and secondary air fans shall be direct shaft driven by the motorand provide combustion air to the furnace. The air fans shall be motor driven and draw air viathe air heater (at low steam pressure) from the waste bunker to ensure that odours and dustsare drawn into the incineration stream and prevented from escaping directly from the tippinghall into the environment.

At least, the following furnace parameters shall be controlled from the DCS:

• quantity of undergrate air in each zone

• speed of grates

• speed of feeders

• quantity of secondary air

• burner operation

Flow measurement of the primary air shall be with equipment designed for a dusty environmentand be self-cleaning.

The Contractor shall present whole life cycle assessment costs in the choice of refractorymaterial. The tube walls in the flame area are to be covered with high quality refractory retained



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bysuitable anchors. Inconel overlay and wear tubes shall be considered for all the first pass(roof included) in order to minimise corrosion and improve life.. The Plant design shall take intoaccount this overlay.

The grate bars shall be manufactured from high-grade chrome cast iron alloy capable of goodlongevity, withstanding high temperatures and being easily removed and replaced. The

Contractor shall specify life and replacement profiles. The grate bars shall be powered in sucha manner as to provide variable control of the reciprocating or rotating movement. Thehydraulic mechanism shall be filled with fire resistant oil. Hydraulic equipment shall be to highquality standards to minimise leaks. The Contractor shall ensure that such fittings can bepurchased locally. Good quality, fine mesh strainers shall be provided in the hydraulic system. A waste hydraulic oil storage tank shall be provided and suitably piped for draining down thehydraulic system.

All lubrication for the grate, feeder and discharger shall be centralised for ease of maintenance.

Operation of auxiliary burners shall be protected by the effective and reliable use of flameprotection cells to specifically monitor the burner flame as opposed to the waste combustion.

The grate ash and boiler ash streams shall be collected together to constitute bottom ash.However the Plant shall possess a flange connection that enables boiler ashes to be collectedseparately. The Contractor shall ensure that the boiler design allows the future modifying andeasy separation of the boiler ash from the bottom ash by directing the boiler ash to the FGTresidue using suitably designed conveyors. The Contractor shall submit the conveyingarrangement to the Purchaser for review prior to construction.

The Plant shall possess thermowells positioned on the front and back walls of the furnace tomonitor fire positioning in the combustion chamber. Provision in the furnace shall be made forthe installation of infrared cameras and associated equipment in order to monitor the furnacefire. The DCS shall be compatible with the future installation of infrared cameras.

In order to meet the NOx emissions limits, the Contractor shall install SNCR. These systemsshall be integrated with the DCS. The Contractor shall provide full details of the proposedDeNOx processes. Systems shall be of proven design and operational in Europe.

The SNCR system shall at least include: a duty and a standby pump arrangement, filtration,preparation vessel, instrumentation, injection lances for long life operation in the furnace, quickconnection fittings for ease of maintenance, all necessary strainers, non-return valves, isolatingvalves, loading valves, and piping. Automatic changeover to the standby system, should theduty system fail in service, and shall be provided complete with all necessary controls/electricalitems and alarm indication. The SNCR reagent shall have at least a 3-day storage capacity.

Where the SNCR system is based upon liquid Urea, the SNCR system shall include sufficientequipment to receive dry Urea prills in bulk and process this to provide liquid urea of the correctstrength and quality. The water volume and quality requirements of this process shall beincluded in the plant water treatment systems.

2.3.2 Boiler

Heat recovery shall be achieved by means of an integral water tube boiler.

The boiler shall be designed for a steam outlet temperature of up to 400ºC. The boiler shall be

designed for 100% MCR and a 250,000 hours operating life in accordance with BS 1113 andresist erosion and corrosion.



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The boiler shall be designed with a 10% temporary overload above MCR for 1 hour in every 24hours. The Contractor shall declare the boiler design philosophy including time at temperature,pressure and temperature cycling and testing. The Contractor shall provide the complete boilerdesign file with his O&M manuals. The Contractor shall also provide with the O&M manuals theoverall maintenance requirements.

The boiler shall be of horizontal type with rapping cleaning system.

The boiler shall be designed such that no manual cleaning shall be required before 8000 hoursof continuous operation.

The boiler shall be of regulated temperature type, with automatic regulation of flue gas outlettemperature according to tubes fouling.

The boiler tube thickness shall include a declared corrosion allowance. The boiler andassociated equipment shall be of the type and quality suitable for municipal waste incinerationplant service and shall be a well proven design. The boiler shall meet the steam requirementsof the turbine generator as well as all other steam requirements of the Plant. Boiler tube

minimum thicknesses are detailed in Appendix B Data Sheets.

All the boiler first pass, including the roof, shall have Inconel overlay. It shall be the Contractordecision to execute these works either on site or directly in the workshop.

The boiler fabrication shall be maximised at the supplier’s works to minimise fabrication andinstallation work at site.

The Contractor shall design a boiler, which shall incorporate:-exit temperatures to avoid excessive fouling in the furnace-combustion chamber sized for low gas velocity and long residence time-adequate spacing of tubes in the tube banks to prevent bridging of tubes by fouling and

allow access for repair-cleaning of boiler pressure parts by methods of well-proven design. If provided,sootblowers shall be of the semi-retractable type.-superheaters providing steady steam temperatures matched to turbine operatingconditions-system to control and maintain a steady boiler outlet flue gas temperature during alloperating periods

All vessels within the steam circuit, including condensate drum and deaerator shall be designedto BS 5500 Category 2 with NDT reviewed by the Purchaser.

The boiler drum shall have at least two independent water level gauges and comply withBS1113 section 7.3.1.

The Contractor shall state the full and part load steam conditions, which at least shall be met.

The boiler shall be insulated to ensure that the surface temperature is not higher than 50°C.External cladding shall be minimum 0.75mm aluminium.

The superheater shall be installed with the inlet and outlet headers located outside the flue gasstream.

Deadends shall be avoided in the design of the boiler.

Access doors and inspection holes shall be provided to enable satisfactory access to theconvective passes and to enable the furnace to be observed. These inspection doors shall be



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suitably large enough to enable on-line cleaning with high-pressure water. Inspection doorsshall be positioned face to face on the same horizontal plane and at waist/shoulder levelrelative to the walkways. Walkways shall be suitable for all maintenance, access and cleaningactivities.

2.3.3 Steam and Feedwater Pipework

All equipment and pipework shall be insulated to ensure that the surface temperature is nothigher than 50°C. External cladding shall be minimum 0.75mm aluminium.

The high pressure and low pressure, steam and feed water pipework shall be designed andmanufactured in accordance with BS 806. Welding and testing shall comply with the PurchaserQuality Plan.

All steam and feedwater pipework shall be adequately supported. Wherever possible,expansion shall be accommodated within the pipework arrangement. The Purchaser shall havethe final opportunity to reject expansion joints.

A cold water fill system shall be provided for leak testing.

All pumps wherever located in the Plant shall be provided with adequate bypasses to avoidoverheating in continuous operation against closed valve.

Motorised vent valves on the boiler drums shall be provided with remote control from the DCS.Start up vents and safety valves shall be silenced by means of silencers to minimise noiseemissions in the event of the following: start-up, shut-down, air cooled condenser trips, etc.Vents and drains shall be located to provide easy operational access and allow discharge totundishes. Vent drains shall be fed back to the feedwater system via a suitably sized andlocated flash drum.

Feedwater heating shall be provided to optimise the thermal cycle.

Valves shall be positioned in vertical steam pipework wherever possible. The steam pipeworkshall be tested to ensure the integrity of all valves.

A “double isolation valve and drain” philosophy shall be applied to the design of the steamsystem pipework and equipment to enable online maintenance of all main equipment items.

All safety valves shall meet BS 1113 requirements and shall be to the approval of thePurchaser’s statutory boiler insurer. These valves shall be designed to adequately pass therequired flow of steam and water without blowing back.



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2.4 STEAM TURBINE, GENERATOR AND ASSOCIATED STEAM SYSTEMS

2.4.1 Steam Turbine

Steam turbine shall be designed to API 612, NEMA SM 24 for piping forces and moments, and

BS EN 60045. Deviations from these Codes proposed by the turbine manufacturer shall besubject to approval by the Purchaser. The Contractor shall state the forces and moments on theturbine in cold and hot conditions and state how the forces and moments due to dead-weightwill be minimised.

The steam turbine shall be designed for 110% MCR steam flow.

A high efficiency turbine shall be specifically provided by the Contractor in order to maximisethe electricity and, if notified by the Purchaser, heat generated by the EfW plant. The designshall be well proven in small and medium sized power stations worldwide. The turbinemanufacturer shall demonstrate reliable operation of reference machines at the condensingconditions.

Upon loss of the main 33kV export system whilst the turbogenerator is running, the turbineoutput shall automatically reduce in a stable manner to island mode without tripping.

The preferred turbine shall be single or multiple cylinder, multistage, condensing type with ahorizontal split design and axial or vertical flow design. Steam takeoffs shall be provided forplant use and, unless otherwise agreed with the Purchaser, to provide for the district heatingtake off. The Contractor shall advise the number, pressure and maximum flow of the districtheating steam takeoffs.

The turbine rotor shall be machined from a solid steel forged block. The turbine shall bedesigned such that the first and second lateral critical speeds are well outside the turbine

running speed. The complete rotor shall be dynamically balanced.

The Contractor shall state the vibration levels of each element of the steam turbine-gearbox-generator.

All steam turbine inlet and exhaust pipework shall be fitted with an isolation valve and a ringposition to enable an isolation spade to be inserted in order to fully isolate the turbine withoutshutting down the process. The valve shall be motor or pneumatically actuated and operate andseal effectively and the time from fully open to closed sealing position shall be less than 2hours. The Contractor shall provide the spades and rings for each location. A bleed valvearrangement shall be provided between the valve and the ring position.

All turbine casing drains shall have double isolation using master/martyr valving principles.

The steam turbine, gearbox if applicable, and generator shall be located in a noise proofed areaand be protected with a fire protection system. This shall also be to the satisfaction of the LocalFire Officer. If a liquid spray system is installed, the turbogenerator package shall be suitablydesigned for liquid deluge conditions such that there are no deleterious effects on the following:motors, lube oil tank vents, lube oil quality and control systems.

Upstream steam pressure shall be regulated through the turbine by the governor-controlledsteam admission valves. The governor valves shall operate sequentially to provide maximumefficiency corresponding with the design rating of the boiler at 100% MCR.

The operation of the turbine and auxiliaries shall be interfaced with, controlled from anddisplayed on the DCS. The Contractor shall supply and install a full health monitoring system



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which can be externally interrogated via function analysers; recording devices and also bymodem.

A turbine maintenance crane shall be provided suitable for the lifting and removal of theelements of the turbine-gearbox-generator onto road vehicles. The crane shall be capable oflifting the heaviest element clear, including turbine rotor withdrawal, without disturbing the

existing ducting, cabling and associated equipment from the rest of the turbine-gearbox-generator assembly except as agreed by the Purchaser. All special tools and lifting beams forthe maintenance and overhaul of the turbine-gearbox-generator assembly shall be provided bythe Contractor.

Drains from the steam pipework and casing shall be provided to heat the turbine casing fromcold within 2 hours.

All pipework sections between boiler drum and turbine shall be subject to a steamblowprocedure to be agreed between the parties. A calculation shall be presented no later than 12months after notification to proceed tabulating the steam flows, pressures and disturbancefactors to be achieved at inlet and outlet of each pipework section during the steamblows. In

addition the turbine shall be protected with inlet steam strainers during commissioning andstart-up. All necessary steam blow-down pipework and silencers shall be provided by theContractor.

The turbine foundation shall be designed using a three dimensional dynamic calculation to DIN4024/BS 4675 Part 1 Class IV as well as to the approval of the turbine maker.

Combined stop and emergency valves shall be provided on the inlet and extraction pipework toprevent turbine overspeed in any circumstances.

Inlet Governing Valves shall provide stable modulating control of the steam pressure at allloads.

A gland steam exhauster system consisting of a condenser and fan exhauster shall recoverheat and condensate to the feedwater system, while non-condensable gases are exhausted toatmosphere outside the building.

The turbine oil system shall meet API 614 and shall supply oil for lubricating the turbine andgenerator main and subsidiary bearings as well as for hydraulic operation and servo-control ofthe governing and emergency valves. Deviations from API 614 proposed by the turbinemanufacturer shall be subject to approval by the Purchaser.

The main oil pump shall be ac electric and supply oil to the complete assembly for bothlubrication and power control purposes. A standby pump shall be provided to start in the eventof failure of the main pump. A dc or ac UPS rundown/cooling pump shall be supplied for safestoppage in case of failure of the main pump. A high pressure control oil system shall bepermitted.

Lubrication oil shall be passed through one of two 100% heat exchangers and a duplex filter forremoving particles down to at least 5 microns. A lube oil centrifuge shall be provided for lube oilconditioning together with fan extraction vented to the outside.

The emergency dc or ac UPS driven pump which operates on low pressure in the event of boththe main pumps being unavailable for maintaining bearing lubrication, and shall maintaineffective cooling for a sufficient length of time, while the unit coasts to a halt and is

mechanically or hand barred.

The turbine shall be protected with a mechanical overspeed trip device and an electronic



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overspeed unit using speed sensors and operating a 2 out of 3 voting system. The subsequentloss of oil pressure causing the stop valves to rapidly close and the governing valves to close.The vacuum condensers shall be designed for full vacuum to protect against turbine trip.

The reduction gearbox shall be designed to API 613 with minimum service factor of 1.1.

The steam turbine shall be fitted with motor driven barring gear.

Hand barring facilities shall also be provided independent of the ac motor driven barring gear.This barring shall be demonstrated to be easy enough for a single employee. Sufficient accessshall be provided to achieve effective handbarring.

2.4.2 Generator

The generator shall consist of a synchronous 2 pole or 4 pole totally enclosed cooling air-cooling water (CACW) machine excited by rotating diodes with no brushes or rings. Thegenerator shall be designed for 110% MCR and a 0.8 power factor. The generator shall be

designed for 120% overspeed with BS 2757 class F insulation. The generator shall complygenerally with BS 5000 Part 2. The generator shall be mounted on a discrete baseplate whichshall also accommodate a shaft mounted fan and which may be common with the turbine andgearbox baseplate. The exciter shall use a brushless rotating rectifier system and be mountedon the baseplate. Careful provisions shall be made to avoid any possibility of oil contaminationof the windings from bearing leakage.

The generator shall be supplied with appropriate excitation cabinet containing:-auto excitation controller for voltage control, power factor-neutral point cabinet with current transformers, earth resistor with a homopolardetection core and connection terminals.-monitoring panel containing the following: line voltage meter, excitation ammeter,

wattmeter, phase meter, frequency meter, duplex voltage meter, duplex frequencymeter, a synchroscope, emergency stop switch, power factor control, voltage andcurrent excitation control, automatic or manual control, control for turbine speed,generator voltage, generator power factor

Stator laminations shall be punched from low loss electrical sheet, coated with an insulatingfilm, to minimise eddy current losses. The stator coil insulation shall be fully rated Class F. Aminimum of six RTD's shall be embedded in the stator winding for sensing temperature.

The synchronous rotor shall be of a solid, single piece construction in which the pole bodies,pole tips, spider and shaft are machined from a single steel forging. The machine rotor shallhave Class F insulated strip-wound field winding applied to the pole bodies.

After assembly the generator shall be run at rated speed, rated voltage and frequency for a finalcheck to ensure vibration is within the required limits.

Brushless Excitation System shall consist of a stationary exciter field, the exciter rotatingelement generating 3 phase AC power, plus the rotor mounted rectifier system. The field coilshall be wound Class F insulated, and vacuum pressure processed in epoxy resin. Thearmature shall be a laminated core supported by a spider, which has provision for mounting onthe generator shaft and for mounting the converter on the armature. The laminated core shallbe made up of resin enamelled magnetic steel punchings. The 3 phase armature windings arerandom wound coils that are coated with epoxy resin under vacuum pressure. The AC-DC

converter shall be made up of solid state rectifiers mounted on revolving case aluminium heatsinks. The rectifier system shall consist of silicon diodes, thyristors and static switchingdevices.



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Terminal box enclosure shall contain three line leads with surge capacitors, currenttransformers and lightning arresters. Also three neutral leads with different currenttransformers.

The governor programmable microprocessor control unit shall control the turbine speed and

accept an external control signal generated from boiler outlet steam pressure, and provide allthe control functions required to maintain safe operation of the turbine. The control unit shall befully interfaced with the DCS and the boiler control system.

2.4.3 Associated Steam Systems

Condensers and associated pipeworkExhaust steam from the turbine shall be ducted to an air cooled condenser. The unit shallperform in a vacuum condensing mode under all turbine operating conditions. The design andprovision of auxiliary equipment shall permit the condenser to function as a dump condenserwhen all or any proportion of the steam flow bypasses the turbine.

The turbine bypass valve shall be of proven design and be capable of tight shut-off and longterm full flow operation without erosion and comply with leakage rates to Class V ANSI/FCI 70-2 1991.

Condenser fan motors shall be variable speed type and be protected with vibration monitoringinstrumentation.

Bursting discs shall not be permitted for pressure relief in any part of the steam system. Acombination of bursting disc and relief valve shall be permitted to protect the turbine exhaustand ACC and sized and positioned to avoid the bursting disc breaking under operationalevents, such as ACC fan failure, island mode, turbine bypass.

At the earliest opportunity following erection the Contractor shall vacuum test the condenserusing temporary exhausters, if necessary. Vacuum decay test shall not exceed 50mbar/hourfrom 0.07 bara.

The condenser capacity and system absorbed power shall be optimised by producing turbinepower generation versus exhaust pressure curve against the local average temperature data.These shall be provided by the Contractor for review by the Purchaser.

Condenser power consumption shall be displayed on the DCS and incorporated into theperformance monitoring system.

Condenser performance shall be demonstrated using an agreed standard such as VDEWRegulation "Acceptance and Operational test of Air Cooled Steam Condensers".

The condenser supporting structure shall allow adequate full air entry and discharge takingaccount of all adjacent restrictions. The Contractor shall ensure a suitable condenser designand orientation, which avoids hot air recirculation through the air condensers.

Condensate systemsThe ducts, pipework and valves included in the main steam duct between turbine and steamcondenser, condensate pipework connecting condenser, condensate tank, condensate pumpsand flow control valve shall have the following:

-isolation of the turbine exhaust without interrupting the operation of the boiler.-vacuum line from the condenser to the ejectors



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-condensate pump isolating valves and non-return valves and all necessary upstreamfilters, drain and vent valves.-pump isolation valves and non-return swing check valves.-vacuum breakers are not required as system shall be designed for full vacuum.- bursting discs shall not be permitted for pressure relief in any part of the steamsystem.

- the air condensers design shall also meet the 10ºC ambient air temperature condition.-the design systems and configuration chosen shall not limit the ability of thecondensers to operate at 100% MCR at less than atmospheric pressure with 30ºC airtemperature in the dump mode in the event that one condenser fan is non-operational.

The condensate tank shall be sized for at least 5 minutes storage capacity at design throughputbetween the upper and lower operating levels. The Contractor shall justify and demonstrate theadequacy of the design.

Two 100% duty centrifugal condensate pumps shall be provided.

A separate steam hogger ejector shall be provided for start-up.

The condensate tank level shall be monitored with high and low level alarms and shall bemaintained at minimum levels using a bypass from the condensate return line.

The condensate and treated water tank shall be epoxy lined or have other protection againstcorrosion. These tanks should be sized to enable prompt boiler start-up and shutdown.

A spray type deaerating heater and feedwater storage tank shall be provided operating atapproximately 130oC. The storage tank below the deaerator shall be designed for 20 minutesstorage capacity at design throughput between the upper and lower operating levels. Thedeaerator shall be fitted with an off-gas condenser and shall meet a residual oxygen contentguarantee of less than 0.02 mg/litre. Dearator performance and related reagent consumptions

shall be referenced to the Plant Operation Guarantee Schedule in Schedule 7.

Boiler feed pumpsElectrically or steam driven boiler feed pumps shall be provided with one pump acting asstandby.

Centrifugal boiler feed pumps shall be designed and tested to API 610 or other manufacturerstandard as approved by the Purchaser. The rated capacity shall not exceed the capacity at thebest efficiency point of the pump curve. The impeller diameter shall be not exceed 95% of themaximum impeller diameter for the pump casing. The pump shall be witness tested for NPSH atthe manufacturer’s works to meet BS 5316 Class B or other standard as approved by thePurchaser. Stainless steel strainers shall be fitted in the suction lines to the boiler feed pumps.

The pump discharge pipework shall be fitted with double isolation, which may be achievedthrough a lockable non-return valve, and an isolation valve downstream of each boiler feedpump.

2.4.4 Water Treatment and Makeup Facilities

General The intent of this section is to define a complete Water Treatment and Makeup Facility capable

of continuous satisfactory operation with the minimum of maintenance. The Contractor shallpropose a water treatment system based on towns water.



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The Facilities shall be designed for the bulk delivery of materials and chemical products with nomanual handling of caustic soda and should be located in a closed room. All materials shall besuitable for a corrosive environment. The area shall be designed for wash down and all junctionboxes shall be designed to at least IP65.

The Contractor shall provide a suitably sized boiler water connection point for the rapid filling of

the boiler by external means.

Boiler water treatment plantThe equipment shall be located in a bunded area with additional bunds for each tank. Tankbunds shall be suitably coated for acid or alkali resistance and the floor shall be epoxy coatedand laid to falls. The plant shall treat towns water and have a total capacity allowing a minimumof 2% of losses peak flow and a minimum storage tank volume of at least 150% of the capacityof the boiler. The treated water quality shall equal or be better than to BS2486 Table 3 for watertube boilers up to 60 bara with conductivity less than 5 micro ohms/cm and silica content lessthan 0.02 mg/l SiO2

The water treatment plant shall be self contained in terms of control and monitoring equipmentwith status monitored via DCS control system. Automatic ion exchange regeneration shall beinitiated by a water flow meter with conductivity cells, pH meter and silica analyser constantlymonitoring the outlet water quality. Resin traps shall be provided downstream of the ionexchange vessels.

Boiler feedwater dosing package A boiler feedwater dosing package shall consist of the following major components:-pH adjustment chemical stock tank and dosing pumps.-oxygen scavenger stock tanks and dosing pumps.-additional chemical stock tank and dosing pumps.

-amine inhibitor chemical stock tank and dosing pumps.

The boiler feedwater dosing package shall be self contained in terms of control and monitoringequipment and shall be fully automatic in normal daily operation. The status of the plant shallbe monitored via control system to the DCS.

Two chemical dosing pumps shall be supplied with each chemical dosing package, one dutyand one standby. The pumps shall be complete with all necessary strainers, non-return valves,isolating valves, loading valves, piping etc. Automatic changeover to the standby pump, shoulda duty item fail in service, and shall be provided complete with all necessary controls/electricalitems and alarm indication.

Chemicals typically for, but not limited to, pH adjustment, phosphate and amine inhibitor shallbe injected directly into the boiler drum. The oxygen scavenger chemical shall be injected in thedeaerator through a stainless steel injection quill. Stainless steel capillary pipework shall beused for the injection of all chemicals. Provision shall also be made for dosing of amine inhibitorinto the steam main.



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2.5 FLUE GAS TREATMENT EQUIPMENT, ASH AND METAL SEPARATION

2.5.1 FLUE GAS TREATMENT EQUIPMENT

2.5.1.1 General

The Contractor shall install a dry flue gas treatment system, which is designed to be easilyadapted with further equipment to meet more stringent emission regulations.Particularly, the Plant shall be convertible in a semi-dry system with simple modification of theeconomiser and with the addition of a reactor. Place shall be let to allow these modifications.The Contractor shall consider various emissions scenarios with the Purchaser to identify spacein the FGT layout for future equipment. A semi-dry option shall be presented, showing specifically the possibility to implement thismodification.

The FGT shall allow place for the addition of, as a minimum, a two fieldselectrostaticprecipitator: this device could be added to do pre-separation of dust and recirculation of

reaction products only.

Flue gas treatment equipment shall be provided consisting of:

• a gas scrubber (as an option)

• a Fabric filter containing fabric filters

• reagent injection system (slaked lime),

• activated carbon injection system

• system for removal of waste/recycled product from the Fabric filter

• quicklime reagent preparation and distribution system (as an option)

• activated carbon preparation and distribution system (as an option),

• bulk reagent storage facility capable of receiving bulk deliveries of reagent

• NOx reduction system

• flue gas sampling points

• forward feeding HCl monitoring and control system which guarantees spikes not exceedingthe guaranteed emission requirements whilst processing Acceptable Waste.

The flue gas treatment system shall be designed to meet the emission requirements detailed inSchedule 7.

The Contractor shall as far as possible ensure that the FGT equipment spares such as silo ventfilters, instrumentation, bag filters, motors, etc shall be kept to a minimum by standardising the

equipment.

Convenient openings shall be provided for duct cleaning.

The flue gas treatment system shall be capable of continuously treating the full operating rangeof gas flow 60% to 100% MCR and shall also be capable of treating short term peaks in the fluegas flow within the capacity of the firing diagram, including overload.

The Contractor shall provide adjustable temperature heat tracing to vessels and ductworkwhere required to ensure that blockages do not occur. All vessels and ductwork shall bethermally insulated and clad to prevent heat loss.

Screw conveyors with intermediate bearings shall only be permitted after Purchaser’s review.



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Pipework shall be designed with drawn or long radius bends to minimise blockages.

Air connections should be provided to unplug blockages.

2.5.1.2 Reagent and Activated Carbon Storage

Reagent shall have at least 5 days storage capacity and make best use of delivery truckcapacities to minimise delivery costs. These vessels and pipework shall be designed for longcorrosion free operation, the effective filling from articulated vehicles containing reagent and forthe blockage-free emptying to the reagent mixing and atomiser/injection equipment.

Option: A standby lime slurry pump shall be provided per Plant. The pumps shall be complete with allnecessary strainers, non-return valves, isolating valves, loading valves, piping etc. Nonautomatic changeover to the standby pump, should a duty item fail in service, and shall beprovided complete with all necessary controls/electrical items and alarm indication.

The Contractor shall ensure that the lime preparation room is provided with a heating system.

The Contractor shall provide a lime slaker grid to ensure that inerts are not introduced into theslaking process.

The FGT system shall be supplied with a dual feed for towns water and raw water.

2.5.1.3 Scrubber Reactor (as an option)

The reactor vessel and associated mechanical handling equipment shall be designed to allowrapid changeout of the reagent atomisers or injection devices making use of quick couplingsand connectors. A standby lime turbine shall be provided at the Plant. A spare atomiser/injectorposition shall be located on top of thereactor. A cover plate shall be provided on the atomiser

flange to avoid ingress of materials and air during changeout of the atomiser.

The atomisers/lime turbines and shall meet the availability requirements specified in Schedule7. Chemical storage tanks and pipework shall be designed for blockage-free operation with110% bunded tanks. The Contractor shall conduct a HAZOP study for this installation and thedesign of the cleaning system shall be reviewed and approved by the Purchaser.

The reagent feed control system shall be PLC based and interfaced with the DCS.

Viewports and manholes shall be provided to enable easy and safe inspection of the interior ofthe reactor. Support points shall be provided to enable easy scaffold erection, and shall notaffect the flow of dried reacted reagent to the discharge conveying system. Manholes for theremoval of reagent shall be at least 1000mm x 500mm to allow reagent to be dug out andremoved effectively.

Thermal insulation shall be provided to ensure there are no cold spots and no steel is in directcontact with the atmosphere. Hopper heaters shall be included to keep the walls warm andprevent condensation. Hammer blocks and chain arch breakers shall also be provided tocounteract any bridging.

The reagent mixing equipment shall be designed to allow the direct feeding of reagent via bigbags or similar into the mixing vessel to enable the flue gas treatment equipment to continueoperation in the event of a blockage in the hoppers.

The Contractor shall install a nozzle on the mixing tank for connection to a future secondpreparation tank and allow sufficient space in his layout design for the future installation of a



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second preparation tank.

2.5.1.4 Fabric filter

The Fabric filter shall be consist of filter bags made from Ryton or P84 or coated glassfibre orGore-Tex with access platforms, safety locking access doors and bypass ducts. The Fabric

filter shall be a modular design with on-line cleaning and the ability to isolate one compartmentsuch that performance remains within emission limits.

Fabric filter design velocities shall be limited to 65m/hr.

The Contractor shall provide maintenance procedures, which describe how the maintenance offilter bags can be achieved safely with a filter compartment isolated.

The Contractor shall provide filter bags with a service life of greater than 4 years.

Stairs shall be provided to access to all platforms. A walking route shall be provided whichdirectly links the flue gas treatment Fabric filter to adjacent plant equipment at a similar level.

In order to avoid cold spots, the insulation arrangement shall be such that no steel is in directcontact with the atmosphere.

There shall be sufficient headroom above the Fabric filter to ensure that the complete bagsection can be readily removed and a new bag installed without difficulty.

The cleaning sequence shall be such that it avoids creating preferential paths for the gasthrough the Fabric filter. The system shall be normally fully automatic. Manual cleaning of anyrow of bags shall be possible direct from thelocal panel. The filter cleaning cycle shall haveadjustable pulse and interval control.

The hoppers of each Fabric filter compartment shall be provided with heaters to maintain metalsurface temperature at an acceptable level and anti-bridging devices. The Contractor shallensure that the fluidising system gives smooth flow.

A bypass duct and associated dampers for each Fabric filter shall be provided for start-up withauxiliary burners and under emergency conditions. The ducting arrangement shall be such thatair can be recirculated through the system and heated on start-up to achieve the requiredtemperature.

2.5.2 Bottom Ash, FGT Residue and Metals Separation Handling

GeneralFork lift access shall be provided to all ash handling areas.

Bottom and ferrous storage bays shall each be designed for at least four days storage and bedesigned to avoid the build up of materials into piles. The bays shall be designed for a loadingshovel to load ash or metals directly into bulk vehicles. Each bay layout shall be designed toaccommodate 16.5m long articulated vehicles and the layout must allow at least a 7 metreheadroom directly under the bottom ash and ferrous metal conveyors. These areas shall besteel floored or have power floated hardened concrete surface suitable for front loading shovelactivities.

The ash areas and metals bays shall be separated by walls to ensure that smell and gases

emanating from these areas do not contaminate the atmosphere of the main Plant. Any liquidsdrained from the ash and ferrous shall be contained and reused within the process.



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The Contractor shall have facilities to sample bottom ash and FGT residue from within theprocess.

Bottom Ash and Metal Separation

The Contractor shall propose a conveyor arrangement for review by the Purchaser.

A ram bottom ash discharger shall push the residue ash onto a vibrating or slipstick typeinternal conveyor via a “large item” separator and ferrous separator to a bottom ash storagearea. A bottom ash bypass system shall be installed to enable bottom ash to be routed tocontainers for collection by forklift truck. The bottom ash discharger tank shall be fitted withequipment to enable the discharger liquids to be sampled and injected with stabiliser. Thebottom ash shall be loaded onto bulk vehicles using a shovel loader. External belt conveyorsshall be covered and designed such that no ashes are discharged into the open and thatbottom ash does not collect on the floor of the building. The belt conveyors shall possess atungsten return blade to clean the belts and belt tightening/self-cleaning devices, which can bereadily accessed from the plant floor. The bottom ash conveyor shall be designed so that the

bottom ash is spread and distributed evenly at the back of the bottom ash storage bay and notdischarged into one pile. The bottom ash conveyor shall also be fitted with rotation detectors.The ash discharger shall be supplied with a dual feed for towns water and raw water.

For areas where vehicles require access underneath transportation conveyors betweenfurnace/boiler buildings and the ash storage area, the Contractor shall ensure there is aclearance of at least 5m to enable obstruction free vehicle movement.

A ferrous metal separator of the drum type shall be provided immediately prior to the dischargeof the residue streams into the ash bay. The position of the ferrous metal separator shall beadjustable above the horizontal conveyor and achieve at least the guaranteed ferrous metalrecovery rate. A lifting beam shall be provided above the metal separator. Ferrous metals shall

be discharged to a storage area to be loaded by front loading shovel into articulated vehicles.This floor area shall be designed for front loading shovel activities.

The Contractor shall make provision for the installation and operation of non ferrous separationfacilities located downstream of the ferrous separator.

FGT Residue

FGT residue shall be collected and discharged into fully enclosed silos with at least 4 daysstorage.. The system shall be provided for FGT residues recirculation but shall be able tooperate without it. The Contractor shall take into account all the possible problems associatedwith this system, particularly residues obstruction (moisture) and pipework erosion. Theconfiguration, bending radii, design and material specification of the pipework or the means ofconveying, shall take into account the high wear rate due to erosion, the potential for blockageand any necessary rodding points. All pipework shall be soundly lagged and trace heated.Pneumatic conveyors shall use heated air or dry air with a dewpoint less than -20°C to avoidblockages.

The FGT residue silo shall be kept at a sufficient temperature using temperature adjustableexternal electric or water heating with insulation and cladding on the outside of the silos to

prevent condensation. Manways in the cone shall be provided to enable access to removeblockages. The silo temperature, level and diverter valve positions shall be monitored. TheContractor shall make provision for the installation of a big bag position to collect FGT residues



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upstream of the FGT residue silo in the event of a blockage in the silo itself.

FGT residue Silo and Bagging System

The Contractor shall install a dual FGT residue discharging system, one direct into powdertankers and the other direct into a single line of 2m3 double skinned sealed bags. The FGTresidue silo shall be designed to discharge FGT residue into 20 tonne powder tankers togetherwith associated control and safety equipment. In addition the silo shall also be designed suchthat FGT residue can be routed onto a bagging machine consisting of a single line of 5 bags.The bagging machine shall allow the empty bag to be inflated with air prior to filling, to preventany risk of residue spillage during filling and enable full bags to be handled using a 4 tonneforklift truck.. The full big bags shall be rolled on one roller conveyor and capable of storing atleast five full bags. The whole system shall be internal to the building and protected from windand rain. The Contractor shall ensure forklift truck access to all areas where big bags arelocated and require lifting. The discharge equipment shall be specifically designed to avoidspillage of dust into the environment.

2.5.3 Induced Draught Fan

A variable speed ID fan shall be provided by the Contractor. Greasing of fan bearings shall beaccessible externally to the ductwork and noise attenuation equipment.

2.5.4 Chimney

Where an existing chimney is not re-used, the Chimney shall be self supporting and fullyinsulated complete with test ports and access platforms. The chimney shall be designed for allatmospheric conditions including wind and snow loadings. Vortex shedding studies shall beconducted by the Contractor to confirm the design and these shall be reviewed by thePurchaser.. Suitable access ladder fixing points shall be provided on the chimney above thebuilding to enable inspection to the top. The chimney insulation shall be completely sealed andshall not allow any water or vapour ingress.. The chimney shall be designed to BS 4076 with a25 year life. In addition to the British Standard, the chimney shall receive a paint system with aminimum of 25 year life to first maintenance to BS 5493. The Plant shall be designed to enablethe changing of chimney lamps from the top of the building CEMS platform.The Contractor shall demonstrate and satisfy to the Purchaser and the Environment Agencythat the chimney height is satisfactory.Where emissions monitoring equipment is located in the chimney, the emission monitoringequipment shall be protected from water ingress and all cable entries shall be from below andequipment and terminal boxes shall be at least IP55. The test ports shall be positioned asrecommended by the MCERTS emissions monitoring equipment supplier and in accordancewith ISO 9096, HMIP Technical Guidance Note M1, Source Testing Associationrecommendations and shall enable effective measurement of all gas species. The chimneyshall be provided with permanent access ladders and step off platforms up to the CEMS level

The new plant shall have to re-use the existing stack or at least the existing stack location inorder to avoid Planning permission problems.

The Contractor shall check, and demonstrate to satisfy the Purchaser and the Environment Agency, that the existing stack is suitable for the operation of the new Plant during all its



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Service Life.

The Contractor shall ensure that the flue gases are above their dewpoints at all times.

Test ports shall be provided in the ductwork leading to the Chimney. The test ports shall bepositioned as recommended by the MCERTS emissions monitoring equipment supplier and in

accordance with ISO 9096, HMIP Technical Guidance Note M1, Source Testing Associationrecommendations and shall enable effective measurement of all gas species. The equipmentshall be provided with permanent access ladders and step off platforms up to the CEMS level.The emission monitoring equipment shall be protected from water ingress and all cable entriesshall be from below and equipment and terminal boxes shall be at least IP55.



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2.6 ELECTRICAL SYSTEMS

2.6.1 Electrical Design

Electrical equipment and systems shall comply with all relevant Electrical Regulations,Standards and Codes of Practices including the Distribution Code, EngineeringRecommendations G59, BS 7671 IEE Wiring Regulations 16th edition. The Contractor shall beresponsible for the satisfactory progress and for the timely liaison with Electricity DistributionCompany (EDC) on matters pertaining to the electrical import/export connection, overallprotection and interlocking arrangements for the electrical connection and metering. Thetechnical design and progress meetings shall be organised by the Contractor but initiated anddirected by the Purchaser, who shall chair each meeting and monitor the progress of thedetailed design of the electrical connection and metering. Minutes of meeting and otherrecords shall be written and issued by the Purchaser.

The Contractor shall provide an integrated electrical system for the EfW Plant. It shall providefor the export of power to the local EDC, import power to run the plant when not generatingand for the distribution of power to the plant auxiliaries. A standby power supply shall beprovided as shown in Figure 2(a). Interlocks shall comply with the requirements of the EDC,and satisfy the Engineering Recommendations G59 and the NETA Contract requirements.

The electrical design proposed in Figures 2(a) and 2(b) are intended to indicate how theGenerator Supply interfaces with the main switchboard and this philosophy shall be applied bythe Contractor to the Plant. This in no wa

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