50
NOTE: Refer vendor doc. title Turbomachinery Package Installation Guideline: Compressor and Mechanical Drive Unit, doc no. TPIM 1010 for further details
This subsection describes the shutdown procedures for the turbine package. There are four types of shutdown procedures; normal stop, pressurized fast stop, emergency stop, and control system stop.
Once the turbine is shutdown, operator at SMG-A to stop gas injection at SMDP-B and SMJT-E as necessary by closing the wellhead gas injection choke valves. Close injector well SSV followed by SCSSV from well control-o-maticWHCP unit.
2.4.1
NORMAL STOP
NOTE: Refer to Solar Turbines document title Unit-Control Balance of Plant Functional Specification, doc. no. 3Y041-149007 for more details.
This subsection describes the procedures to initiate a normal stop from the control console. A normal stop shutdown sequence includes a cooldown period, which allows the engine to run with no load for a preset period before the engine is stopped.
1. Press NORMAL STOP Switch (S1011) or select Operation display screen onscreen STOP button. The following events occur:
a. COOLDOWN Light (DS1013) illuminates, surge control valve is opened, and [Cooldown] highlights on Operation display screen.
b. Engine slows to idle speed and continues to run for a preset cooldown cycle.
NOTE : Engine may be restarted during cooldown cycle by pressing ACKNOWLEDGE Switch, RESET Switch, and then START Switch or by selecting Operation display screen onscreen RESET and START buttons.
c. After preset cooldown cycle, fuel system valves close, combustion ceases, and engine begins to decelerate. COOLDOWN Light (DS1013) extinguishes and [Cooldown] indication reverts to normal video.
d. When engine speed decreases below 25%, Slow Roll Time counts down under TIME REMAINING on Operation display screen.
NOTE : The Variable Frequency Drive (VFD) commands the starter motor to a speed of ~2 to 3.5% NGP. As the engine speed continues to slow from 25%, the overrunning clutch continues to overrun until the engine speed matches the starter speed. The clutch engages and the starter maintains the commanded speed until the slow roll timer times out.
e. After preset slow roll cycle, start motor is de-energized. STOPPING Light (DS1011) illuminates, and [Stopping] highlights on Operation display screen.
f. Gas compressors suction valves and discharge valves close and vent valves remains closed to maintain pressure in gas compressors and process piping for a preselected pressurization hold time period.
g. [Running] indication reverts to normal video. ENGINE HOURS/START COUNTER Meter (M210) stops logging operating time.
h. After engine coasts to a stop and rundown timer expires, a preset post lubrication cycle will be initiated.
i. After preselected pressurization hold time period ends, vent valves open to depressurize compressors and process piping and seal system is de- energized.
2.4.2
PRESSURIZED FAST STOP
NOTE: Refer vendor doc. title Unit-Control Balance of Plant Functional Specification, doc no. 3Y041-149008 for further details
A pressurized fast stop causes the unit to stop with the compressors pressurized, and vent valves and blowdown valves remain closed. To initiate a pressurized fast stop, press the customer- furnished FAST STOP (REMOTE) Switch (S513). The following events occur:
1. Compressor suction valves close, discharge valves close, vent valves, and blowdown valves remain closed to maintain pressure in gas compressors and process piping for a preselected pressurization hold time period.
2. Engine shuts down immediately with no cooldown cycle. Slow roll cycle is bypassed, STOPPING Light (DS1011) illuminates, and [Stopping] highlights on Operation display screen.
3. ENGINE HOURS/START COUNTER Meter (M210) stops logging operating time.
4. After engine coasts to a stop and rundown timer expires, a preset post lubrication cycle will be initiated.
5. After pre-selected pressurization hold time period ends, vent valves and blowdown valves open to depressurize compressors and process piping and seal system is de-energized.
2.4.2
EMERGENCY STOP
NOTE: Refer to Solar Turbines document title Unit-Control Balance of Plant Functional Specification, doc. no. 3Y041-149007 for more details.
An emergency stop does not include a cool down period, which allows the engine to run with no load for a preset period before the engine is stopped. The emergency stop shutdown should only be used when plant conditions require an immediate shutdown.
52
An emergency stop prevents package operation until the emergency stop shutdown is acknowledged and reset by pressing the local ACKNOWLEDGE and RESET switches and the backup relay system is reset.
NOTE : In the following procedures, display screen indications that highlight in (reverse video) are shown in brackets [ ].
To initiate an emergency stop, press either the EMERGENCY STOP Switch (S1012) located on the turbine control panel or the EMERGENCY STOP Switch (S312) located on the enclosure twin control station. The following events occur:
1. Pressurized hold sequence is bypassed. Compressor suction valves close, discharge valves close, and vent valves open.
2. Engine shuts down immediately with no cool down cycle. Slow roll cycle is bypassed, STOPPING Light (DS1011) illuminates, and [Stopping] highlights on Operation display screen.
3. ENGINE HOURS/START COUNTER Meter (M210) stops logging operating time.
4. After engine coasts to a stop and rundown timer expires, a preset post lubrication cycle will be initiated.
2.4.3
CONTROL SYSTEM STOP
NOTE: Refer to Solar Turbines document title Unit-Control Balance of Plant Functional Specification, doc. no. 3Y041-149007 for more details.
There are two types of control system stops; cool down stop and fast stop. If an unsafe operating condition is detected by the control system, the control system will initiate a shutdown. Depending upon the severity of the shutdown, the control system will initiate either a cool down stop or a fast stop. If the control system stop was initiated due to a condition that is self-correcting, the engine can be restarted after the condition returns to normal. If the control system stop was initiated due to a condition that is not self-correcting, contact maintenance personnel to perform corrective actions.
Cooldown Stop
If a cooldown stop has been initiated, the compressors are unloaded and the engine is shut down in the same manner as a normal stop. There are two types of cooldown stops; cooldown lockout and cooldown nonlockout.
Cooldown Nonlockout (CN) - Cooldown nonlockout shutdowns reduce engine speed to idle for a preset cooldown period before initiating a shutdown. Cooldown nonlockout shutdowns include operator initiated normal stops, operating conditions that reached a shutdown limit because maintenance was not performed, a momentary disruption that causes an out-of- limits condition, and operating conditions that exceed alarm levels but are not serious enough to cause any immediate damage. Cooldown nonlockout shutdowns can be reset after corrective action has been taken or operating conditions revert to normal using either the local or remote acknowledge and reset switches.
Cooldown Lockout (CL) - Cooldown lockout shutdowns reduce engine speed to idle for a preset cooldown period before initiating a shutdown. Cooldown lockout shutdowns typically result from a component failure and not because operating conditions have exceeded alarm or shutdown levels. Cooldown lockout shutdowns may not present immediate danger, but corrective action must be taken to avoid damage resulting from a component failure. Cooldown lockout shutdowns prevent package operation until the shutdown is acknowledged and reset using the local acknowledge and reset switches.
NOTE : Remote acknowledge and reset switches cannot acknowledge or reset cooldown lockout shutdowns.
Fast Stop
If a fast stop has been initiated, the compressors are unloaded and the engine is shut down in the same manner as an emergency stop. There are two types of fast stops; fast stop lockout and fast stop non lockout.
WARNING : When a fast stop shutdown has been initiated due to fire detection, the postlube oil pump will remain energized for a preset rundown period. After the preset rundown period expires, the postlube oil pump will be deenergized for 20 minutes. After the 20 minute time period expires, the postlube pump will cycle on and off for a preset postlube period. If unsafe conditions still exist, the operator must manually abort the post lube cycle by opening the facility contactors for the postlube and backup lube oil pumps.
Fast Stop Nonlockout (FN) - Fast stop nonlockout shutdowns initiate an immediate shutdown of the engine. Fast stop nonlockout shutdowns typically result from a disruption in operation due to abnormal operating conditions and may not require corrective action. Fast stop nonlockout shutdowns can be reset when operating conditions revert to normal using either the local or remote acknowledge and reset switches.
Fast Stop Lockout (FL) - Fast stop lockout shutdowns initiate an immediate shutdown of the engine. Fast stop lockout shutdowns prevent package operation until the shutdown is acknowledged and reset using the local acknowledge and reset switches. In addition to using the local acknowledge and reset switches, fast stop lockout shutdowns initiated due to a microprocessor failure, fire detection, backup overspeed, or pressing of emergency stop switch will require the backup relay system to be reset. Fast stop lockout shutdowns
54
are the most severe shutdown types and require corrective action before the package can be restarted.
NOTE : Remote acknowledge and reset switches cannot acknowledge or reset fast stop lockout shutdowns.
Shutdown Initiators
Any of the following process abnormality signals will result an export compressor USD. 1st stage GI compressor scrubber liquid level high high LZAHH-2415
1st stage GI compressor suction pressure low low PZALL-2426 1st stage GI compressor suction flow low low FZALL-2425
1st stage GI compressor discharge pressure high high PZAHH-2427 1st stage GI compressor discharge pressure low low PZAHH-2425
1st stage GI compressor after cooler inlet temperature high high TZAHH-2427A/B 1st stage GI compressor after cooler outlet temperature high high TZAHH-2436 2nd stage GI compressor scrubber liquid level high high LZAHH-2416
2nd stage GI compressor suction pressure low low PZALL-2446 2nd stage GI compressor suction flow low low FZALL-2445
2nd stage GI compressor discharge pressure high high PZAHH-2447 2nd stage GI compressor discharge pressure low low PZAHH-2445
2nd stage GI compressor after cooler inlet temperature high high TZAHH-2447A/B 2nd stage GI compressor after cooler outlet temperature high high TZAHH-2456 PSD
ESD
In addition to this a number of machine related signals can give a USD. For details on this refer to vendors operation and maintenance manuals.
In the event of crash shutdown is initiated check the following actions occur. 1. Check lube oil supply from run down tank is maintained during speed down. 2. Check that fuel gas SABDV has closed.
3. Check that compressor inlet, outlet valves have closed and compressor has been depressurised.
56
2.42.5 Instrument Set Points
Downstream of Gas/Glycol Heat Exchanger at SUPG-B
Tag No. Location/Description Set Point
TIAH-2230 Downstream of Gas/Glycol Heat Exchanger
temperature high 65°C
PSV-2230 A/B Gas/Glycol Heat Exchanger pressure safety valves 8740 kPag (1267 psig)
1st Stage Gas Injection Compressor Suction Scrubber V-2415 at SUPG-B
Tag No. Location/Description Set Point
LZAHH-2415 1st Stage Gas Injection Compressor Suction Scrubber level high high
800mm from vessel bottom
tangent line
LZALL-2415 1st Stage Gas Injection Compressor Suction Scrubber level low low
250mm from vessel bottom
tangent line
LICAH-2415 1st Stage Gas Injection Compressor Suction Scrubber level high
700mm from vessel bottom
tangent line
LICAL-2415 1st Stage Gas Injection Compressor Suction Scrubber level low
350mm from vessel bottom
tangent line
PSV-2415 A/B 1st Stage Gas Injection Compressor Suction Scrubber pressure safety valves
13700 kPag (1986.5 psig)
1st Stage Gas Injection Compressor K-2425 & After Cooler E-2435 at SUPG-B
Tag No. Location/Description Set Point
PZALL-2426 1st Stage Gas Injection Compressor suction pressure low low
5250 kPag (761 psig)
Tag No. Location/Description Set Point
FZALL-2425 1st Stage Gas Injection Compressor suction flow
low low HOLD
PZALL-2425 1st Stage Gas Injection Compressor discharge pressure low low
8870 kPag (1286 psig)
PZAHH-2427 1st Stage Gas Injection Compressor discharge pressure high high
13500 kPag (1975.6 psig)
TZAHH-2427A 1st Stage Gas Injection Compressor discharge
temperature high high 115°C
TZAHH-2427B 1st Stage Gas Injection Compressor discharge
temperature high high 115°C
TZAHH-2436 1st Stage Gas Injection Compressor After Cooler
outlet temperature high high 60°C
PSV-2425 A/B 1st Stage Gas Injection Compressor pressure safety valves
15000 kPag (2175 psig)
Gas Injection Launcher L-2930 and Compressor Seal Gas Supply at SUPG-B
Tag No. Location/Description Set Point
PZAHH-2932 Seal gas pressure high high 17080 kPag
(2477 psig)
PSV-2930 A/B Seal gas line pressure safety valves 18200 kPag (2639 psig)
2nd Stage Gas Injection Compressor Suction Scrubber V-2416 at SUPG-B
58
LZAHH-2416 2nd Stage Gas Injection Compressor Suction Scrubber level high high
800mm from vessel bottom
tangent line
LZALL-2416 2nd Stage Gas Injection Compressor Suction Scrubber level low low
250mm from vessel bottom
tangent line
LICAH-2416 2nd Stage Gas Injection Compressor Suction Scrubber level high
700mm from vessel bottom
tangent line
LICAL-2416 2nd Stage Gas Injection Compressor Suction Scrubber level low
350mm from vessel bottom
tangent line
PSV-2416 A/B 2nd Stage Gas Injection Compressor Suction Scrubber pressure safety valves
17350 kPag (2516 psig)
2nd Stage Gas Injection Compressor K-2426 & After Cooler E-2436 at SUPG-B
Tag No. Location/Description Set Point
PZALL-2446 2nd Stage Gas Injection Compressor suction pressure low low
6600 kPag (960 psig)
FZALL-2445 2nd Stage Gas Injection Compressor suction flow
low low HOLD
PZALL-2445 2nd Stage Gas Injection Compressor discharge pressure low low
20000 kPag (2900 psig)
PZAHH-2447 2nd Stage Gas Injection Compressor discharge pressure high high
25200 kPag (3654 psig)
TZAHH-2447A 2nd Stage Gas Injection Compressor discharge
temperature high high 123°C
TZAHH-2447B 2nd Stage Gas Injection Compressor discharge
temperature high high 123°C
PSV-2426 A/C 2nd Stage Gas Injection Compressor pressure safety valves
28000 kPag (4060 psig)
PSV-2426 B 2nd Stage Gas Injection Compressor pressure safety valve
29400 kPag (4264 psig)
TZAHH-2456 2nd Stage Gas Injection Compressor After Cooler
outlet temperature high high 80°C
TIAH-2457 2nd Stage Gas Injection Compressor After Cooler
outlet temperature high 75°C
Gas Injection Launcher L-2930 and Compressor Seal Gas Supply at SUPG-B
Tag No. Location/Description Set Point
PICAH-2430 Gas injection compression discharge header pressure high
24150 kPag (3503 psig)
PICAL-2430 Gas injection compression discharge header pressure low
21850 kPag (3170 psig)
PIAL-2931 Gas injection to SMP-B pressure low 18952 kPag (2720 psig)
60
Tag No. Location/Description Set Point
PZALL-2932
A/B/C Gas injection to SMP-B pressure low low
16408 kPag (2380 psig)
PZAHH-2932 Gas supply to compressor turbine seal gas system 17080 kPag (2477 psig)
Gas Injection Receiver at SMP-B
Tag No. Location/Description Set Point
PEL-2940 Pressure Alarm Low for Gas Injection from SUPG-B 148 barg (2146.6 psig)
Gas Injection Launcher at SMP-B
Tag No. Location/Description Set Point
PEL-2950 Pressure Alarm Low for Gas Injection to SMJT-E 148 barg (2146.6 psig)
Gas Injection Manifold at SMDP-B
Tag No. Location/Description Set Point
PEL-6151 Pressure Alarm Low for Gas Injection to SMDP-B 144.8 barg PEL-4751 Pressure Alarm Low for Gas Injection to SMDP-B 144.8 barg
Gas Injection Receiver at SMJT-E
Tag No. Location/Description Set Point
PEL-2910 Pressure Alarm Low for Gas Injection from SMP-B 145.6 barg (2111.8 psig)
Tag No. Location/Description Set Point PEL-1214853 Pressure Alarm Low for Gas Injection at SMJT-E 144.8 barg
(172962-D)