Power

Datastream | Convert | ProcessBook
 

Integrated Shutdown

small logo

1.0   Purpose

2.0   Overview

3.0   Procedure

3.1   Limits and Precautions

3.2   Lead GT Shutdown

3.3   Integrated Plant Shutdown Full Facility

4.0   REFERENCES

1.0 Purpose

The purpose of this procedure is to provide the normal shutdown activities that will be completed prior to and during shutdown of the facility. Beginning with the shutdown of the Lead GT and continuing on to the shutdown of the full facility.

Back to top

2.0 Overview

This procedure shall be used to provide uniform shutdown of a single unit and the complete block if required when the plant is being is dispatched off-line.   

Back to top

3.0 Procedure

3.1 Limits and Precautions

General Plant

The duration of the shutdown should be evaluated and efforts should be taken to minimize the start-up time of the facility if the plant is expected to be down for a short period. Evaluate the following if the unit is expected to be off for more than 3 days.

  • Chemical Lay-up of the condenser and HRSG
  • N2 blanket of the HRSG drums
  • Complete draining of the HRSG
  • Maintain the Units in Cool down mode until the highest wheel space temp is < 150F.
  • Perform an off-line water wash if time allows.
  • Complete the extended shutdown PM is the unit will off for greater than a week.

Back to top

3.2 Lead GT Shutdown

______Verify shutdown time is in accordance with dispatch generation schedule.

______Verify bypass valves on off-going unit are in calculated set point.

  • HP to CRH (SGG-X008/X008)
  • HRH BYPASS (SGJ-X008/X008)
  • LP BYPASS (SGH-X010/X010)

______Secure GT Evaporator cooling system if in service

______Secure HRSG duct burners (if in service)

______Select “Stop” on the Mark V HMI

______With GT out of mode 6Q, close ammonia injection manual shut off valve and close automatic ammonia shutoff valve (ABV200) on the ammonia line

Continue to run the blower to purge ammonia from the system to prevent collection of condensation.

______Secure HP to IP and IP to LP cont, blow down valves.

______Secure HP to IP and IP to LP pegging steam if in service.

______Record time when GT goes offline.

______Place bypass valves in manual close.

  • HP to CRH (SGG-X008/X008)
  • HRH BYPASS (SGJ-X008/X008)
  • LP BYPASS (SGH-X010/X010)

______Ensure  HRSG MOV block valves close.

  • CRH MOV(SGK X011/X012)
  • HRH MOV(SGJ X001/X002)
  • HP Stop MOV (SGG X001/X001)
  • LP Stop MOV (SGH X013/X013)

______Ensure GT goes on turning gear and record time

______Fill HP drum to normal level and perform the following:

  • Close ACV--X009/X009 (HP Drum level control valve)
  • Close ACV-X006/X009 (S/U FW control valve)
  • Close MOV-X100/X100 (HP FW isolation valve)

______Fill IP drum to normal and perform the following:

  • Close ACV X228/X228 (IP Drum level control valve)
  • Close ACV X231/X231 (IP Drum level control valve)
  • Close MOV X201/X201 (IP FW isolation valve)

______Fill LP drum to +1 inches, and perform the following:

  • Close ACV X437/X437(LP Drum level Control Valve)
  • Close ACV X442/X442 (LP Drum level Control Valve)
  • Close MBV X402/X402 (LP FW isolation valve)

______Secure Boiler feed water pump and HRSG chemical injection

______HRSG chemical injection pumps..

______Secure one circulating water pump.

______Place HRSG start up drain in manual, close

______Place start up vents in auto with set point 50 psi below drum safety setting

Back to top

3.3 Integrated Plant Shutdown Full Facility

______Verify shutdown time is in accordance with dispatch generation schedule.

______One hour before plant shutdown lower cooling tower basin level approx, 5” to accommodate level rise when shutting down main circulating water pumps.

______Increase HP and IP continuous blow down by 10 %.

______Secure GT Evaporator cooling system and HRSG duct burner (if in service)

______Secure pegging steam from HP to IP and IP to LP drums

______Select “Stop Command” on GT MK V and Record time.

______Select STG LOAD CONTROL function on the MK V to 40%,

______Monitor HP steam pressure, if HP pressure falls within 50 psi of IPC set point, Move STG Load Command set point to 30%.

______Select ADMISSION CONTROL PRESSURE to 10% on the MK V

NOTE:  IF HP STEAM PRESSURE DROPS TO 50 PSI OF IPC SETPOINT TAKE STG OUT OF IPC OPERATION

______With GT out of mode 6Q close Ammonia Injection manual shutoff valve and close automatic Ammonia shutoff valve

______As load decreases below 70 MW on the GT lower STG LOAD CONTROL down to 10% to minimize HRSG HP steam pressure decay.

______Secure the performance heater by placing 1GT1/1GT2-TC 4233 (fuel gas temperature control valve) in manual and closed.

______Record GT Breaker Open Time

______Close off HP and IP cont, blow down valves.

______Secure 1 circulating water pump

______Secure 1 Boiler Feed water pump

______Secure 1 condensate pump

______Set STG LOAD CONTROL and ADMISSION CONTRL at zero

______With STG at approximately 10 MW select STG shutdown on DCS.

______Record STG Breaker Open Time

______After STG is off line steam bypass valves may open if so place valves in manual and close.

______Record GT Flame Out Time

______Ensure that HRSG MOV block valves close off except for at least one HP Stop MOV(SGGX001/X001) re-open to maintain sealing steam supply

  • CRH MOV (SGK X011/X012)
  • HRH MOV (SGJ X001/X002)
  • HP Stop MOV (SGG X001/X001)
  • LP Stop MOV (SGH X013/X013)

______With STG below 2000 RPM secure vacuum pumps, open vacuum breaker

______At zero vacuum in the condenser select steam seal off from the MK V and shut down gland exhauster fan.

______Secure HP Stop MOV (SGG X001/X001)

______Ensure STG goes on Turning Gear and Record time

______Fill HP drum to +5 inches and perform the following:

  • Close ACV-X009/X009 (HP Drum level control valve)
  • Close ACV-X006/X009 (S/U FW control valve)
  • Close MOV-X100/X100 (HP FW isolation valve)

______Fill IP drum to +5 inches and perform the following:

  • Close ACV X228/X228 (IP Drum level control valve)
  • Close ACV X231/X231 (IP Drum level control valve)
  • Close MOV X201/X201 (IP FW isolation valve)

______Fill LP drum to +5 inches, and perform the following:

  • Close ACV X437/X437(LP Drum level Control Valve)
  • Close ACV X442/X442 (LP Drum level Control Valve)
  • Close MBV X402/X402 (LP FW isolation valve)

______Secure Boiler feed water pump and HRSG chemical injection.

______Ensure cooling tower is approximately 5” below normal level prior to Securing one Circulating Water pump P-X001B/1A,

______Secure condensate chemical injection pumps.

______Run condensate pump after STG shut down to ensure the exhaust hood Temp. is below 120F.

______Secure condensate pump

Back to top

4.0REFERENCES

GEK

GE Manuals Gas and Steam Turbines

NE Manuals

Back to top

About Us | Email Settings | Policy Manuals | Email Control Room