7. Yazd-System Description for Condensate System.pdf

MINISTRY OF ENERGY IRAN POWER DEVELOPMENT CO.

I P D C

PROJECT : 22 COMBINED CYCLE POWER PLANTS YAZD COMBINED CYCLE POWER PLANT

SYSTEM DESCRIPTION

FOR

CONDENSATE SYSTEM

E REVISED BY MAPNA COMMENT DATED NOV. 07, 2005 Nov.07,’05 Y.K.CHOI Nov.07,’05 H. C. YOO Nov.07,’05 C.H. LEE Nov.07,’05

D REVISED Sep.29,’05 Y.K.CHOI Sep.29,’05 H. C. YOO Sep.29,’05 C.H. LEE Sep.29,’05

C IN CORPORATED MOM DATED 27~31 AUG. AND 08~12 SEP. ‘04 Nov.09,’04 Y.K.CHOI Nov.09,’04 H. C. YOO Nov.09,’04 W. Y. LEE Nov.09,’04

B FOR CONSTRUCTION July 5,’04 Y.K.CHOI July 5,’04 H. C. YOO July 5,’04 W. Y. LEE July 5,’04

A First Issue Dec.5,’03 D.C.KIM Dec.5,’03 H. C. YOO Dec.5,’03 W. Y. LEE Dec.5,’03

REV DESIGNATION DATE DESIGN DATE CHKD DATE APPROVED DATE

DOCUMENT NO. : MP-YZC-GA-04-HN0-001 REV. E MAPNA C o . ( PRIVATE JOINT STOCK )

IRAN POWER PLANT PROJECTS MANAGEMENT Co. CONTRACT NO. : 22-0701/BA/TL PAGE 1 OF 9

ORIGINATOR NO. : YZC-A-SP-470-SDE-003 A4 ORIGINATOR

DOOSAN HEAVY INDUSTRIES & CONSTRUCTION CO.,LTD. ORIG

LOC.ORIG. DEPT.

PROJ. NAME

DISC.

DOC. TYPE

AREA TYPE

SYS. FA.N

SEQ. N.

SH. N. REV. E

FOR CONSTRUCTION

MINISTRY OF ENERGY IRAN POWER DEVELOPMENT CO.

I P D C

PROJECT : 22 COMBINED CYCLE POWER PLANTS YAZD COMBINED CYCLE POWER PLANT

REVISION REVISION

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DOCUMENT NO. : MP-YZC-GA-04-HN0-001 REV. E MAPNA C o . ( PRIVATE JOINT STOCK )

IRAN POWER PLANT PROJECTS MANAGEMENT Co. CONTRACT NO. : 22-0701/BA/TL PAGE 2 OF 9

ORIGINATOR NO. : YZC-A-SP-470-SDE-003 A4 ORIGINATOR

DOOSAN HEAVY INDUSTRIES & CONSTRUCTION CO.,LTD. ORIG

LOC.ORIG. DEPT.

PROJ. NAME

DISC.

DOC. TYPE

AREA TYPE

SYS. FA.N

SEQ. N.

SH. N. REV. E

YAZD Combined Cycle

SYSTEM DESCRIPTION CONDENSATE SYSTEM

DOOSAN Changwon, KOREA

Contract No. : 22-0701/BA/TL

Doc. No. : MP-YZC-GA-04-HN0-001 Originator No. : YZC-A-SP-470-SDE-003

Revision : E Date : Nov. 07, ‘05 Page: 3 / 9

CONDENSATE SYSTEM

CONTENTS

CLAUSE NO. DESCRIPTION PAGE

1.0.0 REFERENCE DRAWINGS 4

2.0.0 INTRODUCTION 4

3.0.0 CONDENSATE SYSTEM CONFIGURATION 4

4.0.0 DESIGN BASIS OF CONDENSATE EXTRACTION 6

PUMP

5.0.0 OPERATION 6

6.0.0 GENERAL CONTROL DESCRIPTION 8

YAZD Combined Cycle






CONDENSATE SYSTEM 1.0.0 REFERENCE DRAWINGS

• HRSG Feedwater storage section P & I diagrams (MP-YZC-GA-02-HL0-003) • Condensate system P & I diagrams (MP-YZC-GA-02-HN0-001)

2.0.0 INTRODUCTION 2.1.0 The condensate system consists of the following main components;

• Two (2) x 100 % centrifugal, vertical can type condensate extraction pumps

(LCB11/21AP001) for two (2) HRSGs. • Condensate polishing plant (supplied by others). • Ejector condensers (supplied by others). • Gland steam condenser (supplied by others). • Two (2) x 100% level control valves (LCB80AA151/AA152) for each HRSG • Each of the above named components is provided with the necessary piping,

fittings and instrumentation. 3.0.0 CONDENSATE SYSTEM CONFIGURATION 3.1.0 The purpose of the condensate system is

• Return condensate to thermal cycle from the condenser hotwell to the deaerator (HAD80BB002) through condensate polishing plant, ejector condenser, gland steam condenser and condensate preheater maintain the operating level in the feedwater storage tank (HAD80BB001).

• To supply condensate to auxiliary steam system. • To supply condensate to condensate extraction pump (LCB11/21AP001) for

pump sealing in normal operation. The initial seal water for condensate extraction pump is to be supplied from the condensate transfer pump.

• To supply condensate for valve water sealing. • To supply condensate to flash tank (LCM30BB001). • To supply condensate to steam turbine service (HP/LP bypass attemperators, ST

flash/stand pipe filling, sealing water of ST consumers & permanent filling of HP-bypass, Gland steam condenser).

• To supply condensate to chemical dosing

YAZD Combined Cycle






3.2.0 Condensate flow paths:

• Each condensate extraction pump (LCB11/21AP001) takes suction from the condenser hotwell through the condensate common suction line. Only one pump operates at a time. The second pump is in standby.

• Condensate flows from condenser hotwell to the suction of condensate extraction pump (LCB11/21AP001) through a 16 inch pipeline.

• Each pump suction is having a relief valve (LAC10/20AA191), basket type strainer (LCB10/20AT001) with pressure differential switch (LCB10/20CP001) and manual isolating valve (LCB10/20AA201) with limit switch (LCB10/20CG001).

• The condensate extraction pumps (LCB11/21AP001) discharge into common header.

• Each discharge circuit is fitted with a check valve (LCB14/24AA201) and manual isolation valve (LCB14/24AA252).

• Condensate from the pump discharge is piped to the shaft seals of each pump after the check valve (LAC14/24AA201) to prevent air-in leakage when the condensate extraction pump (LCB11/21AP001) is on "auto" standby mode and to provide shaft lubrication. In addition, each pump has a suction vent line (LCB12/ 22AA401) / discharge vent line (LCB12/22AA402) piped to the condenser.

• A branch off from condensate extraction pump (LCB11/21AP001) discharge line prior to condensate polishing plant is provided for supplying sealing water to pump/valves with sealing arrangement.

• A branch off from condensate extraction pump (LCB11/21AP001) discharge line prior to condensate polishing plant is provided for supplying of auxiliary steam system, flank tank (LCM30BB001) and turbine services water.

• A flow measurement device (LCB60CF102) is provided for measuring the total flow of condensate between gland steam condenser outlet and HRSG inlet.

• The minimum flow recirculation system including flow control valve (LCB61AA151) is branched off from the downstream of the gland steam condenser. A minimum flow recirculation to the condenser is controlled by the minimum flow recirculation control valve (LCB61AA151) which protects the condensate extraction pumps (LCB11/21AP001) from overheating by keeping the minimum flow rate requirements, when the system demand is lowered than the minimum flow rate.

• A branch off from condensate line after flow measurement device (LCB60CF102) is provided for supplying of condensate water to chemical dosing system.

• Two (2) x 100% feed water storage tank level control valves (LCB80AA151/ AA152) in parallel, two upstream motor operated valves (LCB80AA053/AA054), two (2) downstream manual valves (LCB80AA253/AA256) are provided for each HRSG.

• Motor operated valves (LCB80AA052) with its integral manual bypass valve (LCB80AA259) is provided for each HRSG before condensate preheater. Motor operated valve (LCB80AA051) is used to bypass the condensate preheater to prevent corrosion of the condensate preheater.

YAZD Combined Cycle






4.0.0 DESIGN BASIS OF CONDENSATE EXTRACTION PUMP 4.1.0 Guarantee point

(19℃ ambient temperature, 32% relative humidity, Supplementary firing, Natural gas, base load without bypass mode) Flow kg/s 157.83*Temperature at pump suction Deg.C 49 Discharge Pressure bara 21.51 Suction Pressure bara 0.117 TDH mH 220 NPSHA @ 1st impeller mH 4.65 NPSHR @ 1st Impeller mH 2.6 BHP kW 452 Aux. Power Consumption kW 470

* Pump self sealing water is not included in this flow 5.0.0 OPERATION 5.1.0 Condensate Extraction Pumps 5.1.1 Preparation for Start-up

The condensate extraction pumps (LCB11/21AP001) are to be started and operated in co-ordination with the HRSG start-up and operation.

Fill-up the condenser to the normal level. Fill-up the feed water storage tank (HAD80BB001) to the normal level by running

the condensate transfer pump and then close the motorized isolating valves (LCB80AA053/AA054) in the suction of the feed water storage tank (HAD80BB001).

Fill-up the condensate extraction pump discharge piping including ejector condenser, gland steam condenser, minimum flow recirculation line, etc., using condensate system fill-up line with the help of the condensate transfer pump.

Fill-up the LP & HP drums, economizers, evaporators and related piping by running the condensate transfer pump.

Check the readiness of the condensate extraction pump and its integral system such as seal water, electrical and instrumentation system as per pump manufacture’s O&M manual.

The pump can be kept running through the minimum flow recirculation control line till the HRSG is ready for start-up.

5.1.2 Starting the first condensate extraction pumps (LCB11/21AP001) Preselect the pump as the first running pump (LCB11AP001). In case of other pump (LCB21AP001), its relative valves and switches shall be considered in the following sequence. When a particular pump is selected for running, the following permissive are to be satisfied. i) Condenser water level is not low.

YAZD Combined Cycle






ii) Suction valve (LCB10AA201) with limit switch (LCB10CG001) is opened.

iii) Suction Vent valve (LCB12AA401) is opened. Discharge vent valve (LCB12AA402) shall be closed after 2 seconds from pump (LCB11AP001) start up.

iv) When GT is running on natural gas firing, the motorized valve (LAC80AA051) in CPH (Condensate Preheater) bypass is closed and When GT is running on gas oil firing, it is required to bypass the CPH.

v) The inlet and outlet isolation valves for Condensate polishing plant/Gland steam condenser/Ejector condenser are kept open.

vi) Minimum recirculation control valve (LCB61AA151) is in Auto-mode and its isolation valve (LCB61AA251) is opened.

vii) The feed water storage tank level control valve (LCB80AA151/AA152) is in Auto-mode and its isolation valves (LCB80AA053/AA054) are opened.

viii) All isolation valves on main condensate line to deaerator are opened.

ix) No trip condition exists. 5.1.3 Tripping of the condensate extraction pump

The running condensate extraction pump shall trip when any of the following condition is true: i) A low alarm is considered in case condensate flow decreases to reach minimum

flow. If the flow decreases to reach a flow lower than minimum flow, after a time delay the condensate extraction pump will trip and valve of minimum flow will be closed.

ii) Condenser level Low-Low.

iii) Motor bearing temperature High-High.

iv) Motor winding temperature High-High. 5.1.4 Alarm of the condensate extraction pump

Condensate extraction pumps will alarms for the following conditions i) Condensate extraction pump failed to start.

ii) Condensate extraction pump failed to stop.

iii) Condensate extraction pump has electrical fault.

iv) Condensate extraction pump tripped.

v) Condensate extraction pump Motor bearing temperature High.

vi) Condensate extraction pump Motor winding temperature High.

vii) Differential pressure across the suction strainer (LCB10AT001) High. (Trip of pump will be decided by operator after a time delay of suction strainer differential pressure switch alarm activated.)

5.1.5 Change-over of the pumps

YAZD Combined Cycle






The changeover of the condensate extraction pumps can be automatically carried out from DCS. The standby pump is kept ready for start-up during normal operation. The standby pump starts automatically in case of the following: i) If discharge header pressure is at the low alarm;

Two pumps (LCB11/21AP001) will be delivering the condensate together during the short time period. And then, if the discharge header pressure is not low, the existing running pump will be automatically tripped and selected as the standby pump.

ii) If running condensate extraction pump trip signal is initiated;

The standby pump shall be started immediately. And then, the running pump will be tripped.

6.0.0 GENERAL CONTROL DESCRIPTION 6.1.0 Minimum Flow Recirculation Control

A pneumatic operated control valve (LCB61AA151) ensures the minimum flow through the condensate extraction pump. Flow device (LCB60CF101) measures the discharge flow of condensate extraction pump. At low loads and start-up, a portion of the condensate flow is recirculated to the condenser to maintain the minimum required flow through the condensate extraction pump, gland steam condenser, steam air ejector.

6.2.0 Condensate Flow Control

Condensate water flow control system is to maintain the feed water storage tank (HAD80BB001) level within the allowable limits by modulating the feed water storage tank level control valve (LCB80AA151/AA152). The feed water storage tank level control station consists of two(2) 100% control valves (LCB80AA151/AA152). One serves as the backup to the other.

6.2.1 Operation with two (2) HRSGs

• The condensate water is supplied to two (2) deaerators by one (1) of condensate extraction pump.

• Heat is recovered in gland steam condenser, ejector condenser and condensate preheater.

• Feed water storage tank level is kept constant by level control valve.

• The minimum flow recirculation control valve is closed.

• The gland steam condenser bypass is closed

• Condensate extraction pump discharge isolation valve (LCB14/24AA252) is opened by manual.

YAZD Combined Cycle






• The sealing water circuit is in operation. 6.2.2 Operation with a single HRSG The same operation as in paragraph above except the condensate preheater of the

stopped HRSG is isolated. 6.3.0 Excess Condensate Dump Control

During plant load change or abnormal operation. The excess condensate water shall be controlled by main cooling water system (Heller) in order to prevent the condenser level high.

7. Yazd-System Description for Condensate System.pdf

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