CO2 EE-00100-CO2-002

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30621127-000-3BD-EE-00100-CO2 REV 002

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30621127-000-3BD-EE-00100-CO2 REV 002

12620-001

QURAYYAH COMBINED CYCLE PLANT SYSTEM DESCRIPTION DOCUMENT NO. EE-00100-CO2

Sargent & Lundy LLC

DOCUMENT NO. EE-00100-CO2 QURAYYAH COMBINED CYCLE PLANT CARBON DIOXIDE SYSTEM DESCRIPTION

Revision 000 001 002

Date 14 May 10 21 Sep 10 25 Apr 11

Purpose Issued For Approval Issued For Approval Issued For Approval

Prepared AJM AJM AJM

Reviewed KB KB KB

Approved PMK PMK SSG

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30621127-000-3BD-EE-00100-CO2 REV 002

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QURAYYAH COMBINED CYCLE PLANT SYSTEM DESCRIPTION DOCUMENT NO. EE-00100-CO2

Sargent & Lundy LLC

1. 1.1

CARBON DIOXIDE SYSTEM System Function The carbon dioxide system is required to supply carbon dioxide for the purging of air and hydrogen from the main generators prior to the filling of hydrogen and subsequent shutdown respectively. The Generator has a large open volume internally. This volume contains hydrogen during normal operation. It contains air during maintenance outages. An inert gas is put into the generator volume as an intermediate gas so that air and hydrogen do not mix inside the generator casing. Carbon dioxide gas is used as the inert gas because it has a substantially higher density and lower thermal conductivity compared to hydrogen or air. For detailed P&ID of Carbon dioxide (CO2 ) System refer to Dwg. No. EA-682813.

1.2

General Description General Purging of generator is carried out to remove the hydrogen gas prior to a maintenance activity. This results in effective inerting the generator. Prior to personnel working inside the generator, the CO2 gas must be purged with instrument air. The second instance a CO2 purge is performed after the generator has been opened up and maintenance has been completed. In this case CO2 is used to purge the generator cavity of air prior to refilling with hydrogen gas. The substantially different properties are used by the gas analyzer (inside the hydrogen cabinet) so that gas concentration during purging can be monitored. The carbon dioxide is supplied from a centralized carbon dioxide storage where carbon dioxide gas is stored in dip tube type cylinder. Open cycle loose carbon dioxide cylinder that are located in CO2 & N2 shelter of Project-B (Item no# 42 in site layout) will be relocated in centralized carbon dioxide gas storage shelter (Item#233 in Site layout) of Project-C. CO2 gas from centralized storage is supplied to both open cycle and combined cycle generators for purging. Combined Cycle carbon dioxide cylinder manifolds are arranged in five groups with each group having dual redundant headers to facilitate removal and replacement of cylinders on one manifold whilst the other manifold is in use. CO2 cylinder are kept in racks with each rack consisting of 16 cylinders. Open Cycle carbon dioxide bottles are also kept in racks with each rack consisting of 16 cylinders. Open cycle carbon dioxide cylinder manifolds are arranged in ten (10) groups with each group having dual redundant headers to facilitate removal and replacement of cylinders on one manifold whilst the other manifold is in use, similar to combined cycle.

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30621127-000-3BD-EE-00100-CO2 REV 002

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QURAYYAH COMBINED CYCLE PLANT SYSTEM DESCRIPTION DOCUMENT NO. EE-00100-CO2

Sargent & Lundy LLC

The redundant header of each rack is connected to redundant main header (C00-025QJK-011-Q0605,C00-025-QJK-012-Q0605) and these redundant main headers are connected to redundant streams each of them provided with a waterbath heater (C00QJK-50-AC-001/002).Downstream of waterbath heater, redundant central pressure reduction station (CPRS) (C00-QJK-50-AA-081/082) are provided. From CPRS, CO2 gas is supplied to STG area pressure reducing stations (two STG PRS - one (C00-QJK-50AA-084) for STG block#1,2,3 and other (C00-QJK-50-AA-083) for STG block 4,5 & 6 (future)) from where CO2 is supplied to Generator Gas Control Station of individual steam turbine generators at required pressure. A low pressure side interconnection is provided from combined cycle header to open cycle enabling supply of CO2 gas supply to Open cycle Gas turbines. Interconnection is provided from downstream of central pressure reducing station (CPRS) and extended to GTG area. Pressure reducing stations (PRS) (C10/20/30/40/50-QJK-50-AA-081) are provided at GTG area (One PRS for each block GTGs) to supply CO2 gas to generator at required pressure. Each GTG area PRS has one orifice in bypass header .A spool pipe with a NRV is added at low pressure side of open cycle CO2 piping. before flow transmitter on pipeline connecting to GE terminal point LE002. QCPP interconnection pipe is connected to this spool pipe (after NRV). At each main header a safety relief valve (C00-WJK-50-AA-195/196) is provided to protect the system from overpressure. Carbon dioxide system consist of following major components /equipments Five (5) banks of QCCPP Carbon dioxide dip tube type cylinder for generator purging. Each bank consists of 40 cylinders. Two (2 x 100%) capacity waterbath heaters (C00-QJK-50-AC-001/002) One (1) redundant pressure reducing stream (C00-QJK-50-AA-081/082) to supply carbon dioxide gas to the generator terminal point at the pressure required for STG / GTG. Two (2) redundant pressure reducing station (C00-QJK-50-AA-083/084) for STG area is provided to supply CO2 to STG at required pressure. Each pressure reducing stream is having orifice (C00-QJK-50-BP-001/002 respectively) in bypass header. Five (5) Pressure Reducing station (C10/20/30/40/50-QJK-50-AA-081), one (1) for each block GTGs is provided to supply CO2 to GTG at required Pressure. Each pressure reducing stream is having orifice (C10/20/30/40/50-QJK-50-BP001 respectively). Ten (10) banks of QCCPP Carbon dioxide dip tube type cylinder for generator purging. Nine (9) banks consist of 40 cylinders and One(1) bank consists of 30 cylinders.

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30621127-000-3BD-EE-00100-CO2 REV 002

12620-001

QURAYYAH COMBINED CYCLE PLANT SYSTEM DESCRIPTION DOCUMENT NO. EE-00100-CO2

Sargent & Lundy LLC

1.2.1

Carbon dioxide cylinder and storage racks Carbon dioxide cylinders of dip tube type will be stored in a storage rack. The cylinders are segregated in storage rack separately for STG purging & open cycle purging. Number of carbon dioxide cylinder is estimated considering three (3) air and three (3) hydrogen purging for each of the five (5) steam turbine generators. Additionally 5% margin is provided to cover leakages. Total 200 cylinders (40 per block) in are kept at central CO2 storage in racks consisting of 16 cylinders each. Total 390 Open cycle cylinders are relocated to central CO2 storage and are kept in racks of 16 cylinders each Number of QCPP cylinder racks - 13 Number of OCPP cylinder racks - 25 Carbon dioxide gas will be supplied from centralized storage shelter (item#233 in Site layout) with dual manifold arrangement to facilitate removal and replacement of cylinders on one manifold whilst the other manifold is in use.

1.2.2 1.2.3

Electrically heated waterbath type evaporators (C00-QJK-50-AC-001/002) with temperature gauges, alarms, thermostats and water level gauges. Central Pressure reducing station, consisting of one self regulating pressure reducing valve (in each header) reduces the carbon dioxide gas pressure to required pressure suitable for distribution to the generator. STG and GTG area pressure reducing station consist of one self regulating pressure reducing valve which reduces pressure to required pressure suitable for distribution to the generator. A ball valve along with orifice is provided in bypass line. Carbon dioxide gas is supplied from storage at 74 barg and pressure is reduced to 11 barg at central pressure reduction stage. Further pressure is reduced to 8.62 barg (required pressure at Generator) at STG and GTG area PRV stations.

1.2.4

1.2.5

Relief valves are located downstream of pressure-regulating valves to protect the system from overpressure. Vents of relief valve will be routed to safe height approximately 1 m above the building/facility. Piping is designed per ANSI/ASME B31.1, Power Piping. Generator purging requirement and interconnecting piping between STG modules are as per STG Supplier recommendations. Low pressure side interconnection is provided between combined cycle and open cycle.

1.2.6 1.2.7

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30621127-000-3BD-EE-00100-CO2 REV 002

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QURAYYAH COMBINED CYCLE PLANT SYSTEM DESCRIPTION DOCUMENT NO. EE-00100-CO2

Sargent & Lundy LLC

pipe sizing of pipe line up to interconnection junction point is sized considering six(6) generator (5 STG+1GTG) simultaneously at any point of time. CO2 Consumption data Total Carbon Dioxide (CO2) gas 247 m3 required for air and hydrogen purge for each generator (at STP condition)

The carbon dioxide gas is stored in cylinder at central storage area. From the storage unit, CO2 will be supplied to combined cycle steam generator terminal point and open cycle CO2 gas supply low pressure side (interconnection junction) at 8.62 barg. See GEs product literature (Attachment 1.11.2) for details of carbon dioxide operating pressure range for each generator design.

1.3

System Operation Normal Operation The operation of the system is manual and as required by the generator manufacturers operating instructions. Carbon dioxide gas flows from the centralized bulk storage through watebath heater and Pressure reducing station (PRS) for distribution to respective generators at required pressure, i.e., 8.62 barg One local control panel will be supplied