6.2 LUBRICATION SYSTEM
6.2.1 Lube Oil System
The lubricating and hydraulic oil requirements for the gas turbine power plant are furnished by a separate, enclosed, forced-feed lubrication module. This lubrication module, complete with tank, pumps, coolers, filters, valves and various control and protection devices, furnishes oil to the gas turbine bearings, generator bearings (absorbing the heat rejection load), starting means, load gear and on dual fuel units the atomizing air/purge compressors as shown in Figure. (6.2) and Figure. (6.3). This module is also used to supply oil for the lift oil system, trip oil system and the hydrogen seals on the generator.
Additionally, a portion of the pressurized fluid is diverted and filtered again for use by hydraulic control devices as control fluid. Refer to “Lubricating Oil Recommendations for Gas Turbines with Bearing Ambient above 500F (260C)” in the fluid specifications section of this manual for the lubricating oil requirements. The lubrication system is designed to supply filtered lubricant at the proper temperature and pressure for operation of the turbine and its associated equipment. Refer to the Lube Oil Schematic Piping Diagram in this section. Major system components include:
1. Lubricant oil reservoir which serves as a base for the accessory module.
2. Two centrifugal pumps (PQ1-1 and PQ1-2) each driven by an AC electrical motor (88QA-1 and 88QA-2). Each AC motor includes a motor space heater (23QA-1 and -2) to prevent condensation in the motor.
3. Emergency oil pump (PQ2-1) with DC motor (88QE-1)
4. Main Seal oil pump (PQ3-1) driven by AC motor (88QS-1). AC motor includes motor space heater (23QS-1).
5. Emergency seal oil pump driven by DC motor (88ES-1). Note, in most instances PQ3-1 is a “piggy-back” AC/DC motor driving one pump. If the Customer has opted to purchase separate AC and DC seal oil pumps, the separate DC pump will be named PQ3-2.
6. Dual lubricating oil heat exchangers in parallel (LOHX-1 and LOHX-2).
7. Two full flow lubricating oil filters in parallel (LF3-1 and LF3-2).
8. Bearing header pressure regulator (VPR2-1).
9. Mist eliminator with redundant fan/motor (88QV-1A and 88QV-1B) and motor space heaters (23QV-2A and 23QV-2B).
10. Pressure Protection Switches (63QA-1A, 63QA-1B, 63QE-1, 63QT-2A and 63QT-2B and on units with liquid fuel 63QA-3).
11. Tank temperature switches (26QL-1, 26QN-1) or tank temperature thermocouples (LT-OT-4A, LT-OT-5A) for pump start permissive and immersion heater control.
12. Lube oil header thermocouples (LT-TH-1A, 1B, 2A, 2B, 3A, 3B).
13. Lube oil drain thermocouples (LT-B1D-1A/1B, LT-B2D-1A/1B, LT-G1D-1A/1B and LT-B2D-1A/1B). Note that LT-B1D-1A/1B and LT-B2D–1A/1B may be single thermocouples named LT-B1D-1 and LT-B2D-1 on some units. The lube oil is circulated by a redundant set of AC pumps. A DC pump is provided in case AC power to the site is interrupted. These pumps are the first of the auxiliary equipment to be energized during a startup.
Sequence. Following shutdown of the unit, these pumps continue to run throughout the extensive cool down period and are the last of the auxiliary equipment to be stopped. The lube oil system is self-contained. After Lubricating and removing heat from the rotating equipment, oil is returned to the lube oil tank. It is cooled by oil-to-water heat exchangers as it is pumped from the tank and re-circulated. Various sensing devices are Included in the design to ensure adequate oil level in the tank, oil pressure, and oil temperature.
All pumps have a check valve on the pump discharge line so that oil does not flow into the tank through a pump, which is not in service. Oil tank temperature is indicated by a thermometer on the side of the tank. Thermocouples connected to the control panel indicate lube oil temperature in the bearing header. Thermocouples in the bearing drains are also wired to the turbine control panel for monitoring. A bearing header oil sampling port is located upstream of VPR2-1.
For turbine starting, a maximum oil viscosity of 800 SUS (173 centistokes) is specified for reliable operation of the control system and for bearing lubrication. Temperature switch 26QN-1 or LT-OT-4A prevents turbine startup if the temperature of the lubricant decreases to a point where oil viscosity exceeds 800 SUS (173 centistokes).
6.2.1 Lube Oil System
The lubricating and hydraulic oil requirements for the gas turbine power plant are furnished by a separate, enclosed, forced-feed lubrication module. This lubrication module, complete with tank, pumps, coolers, filters, valves and various control and protection devices, furnishes oil to the gas turbine bearings, generator bearings (absorbing the heat rejection load), starting means, load gear and on dual fuel units the atomizing air/purge compressors as shown in Figure. (6.2) and Figure. (6.3). This module is also used to supply oil for the lift oil system, trip oil system and the hydrogen seals on the generator.
Additionally, a portion of the pressurized fluid is diverted and filtered again for use by hydraulic control devices as control fluid. Refer to “Lubricating Oil Recommendations for Gas Turbines with Bearing Ambient above 500F (260C)” in the fluid specifications section of this manual for the lubricating oil requirements. The lubrication system is designed to supply filtered lubricant at the proper temperature and pressure for operation of the turbine and its associated equipment. Refer to the Lube Oil Schematic Piping Diagram in this section. Major system components include:
1. Lubricant oil reservoir which serves as a base for the accessory module.
2. Two centrifugal pumps (PQ1-1 and PQ1-2) each driven by an AC electrical motor (88QA-1 and 88QA-2). Each AC motor includes a motor space heater (23QA-1 and -2) to prevent condensation in the motor.
3. Emergency oil pump (PQ2-1) with DC motor (88QE-1)
4. Main Seal oil pump (PQ3-1) driven by AC motor (88QS-1). AC motor includes motor space heater (23QS-1).
5. Emergency seal oil pump driven by DC motor (88ES-1). Note, in most instances PQ3-1 is a “piggy-back” AC/DC motor driving one pump. If the Customer has opted to purchase separate AC and DC seal oil pumps, the separate DC pump will be named PQ3-2.
6. Dual lubricating oil heat exchangers in parallel (LOHX-1 and LOHX-2).
7. Two full flow lubricating oil filters in parallel (LF3-1 and LF3-2).
8. Bearing header pressure regulator (VPR2-1).
9. Mist eliminator with redundant fan/motor (88QV-1A and 88QV-1B) and motor space heaters (23QV-2A and 23QV-2B).
10. Pressure Protection Switches (63QA-1A, 63QA-1B, 63QE-1, 63QT-2A and 63QT-2B and on units with liquid fuel 63QA-3).
11. Tank temperature switches (26QL-1, 26QN-1) or tank temperature thermocouples (LT-OT-4A, LT-OT-5A) for pump start permissive and immersion heater control.
12. Lube oil header thermocouples (LT-TH-1A, 1B, 2A, 2B, 3A, 3B).
13. Lube oil drain thermocouples (LT-B1D-1A/1B, LT-B2D-1A/1B, LT-G1D-1A/1B and LT-B2D-1A/1B). Note that LT-B1D-1A/1B and LT-B2D–1A/1B may be single thermocouples named LT-B1D-1 and LT-B2D-1 on some units. The lube oil is circulated by a redundant set of AC pumps. A DC pump is provided in case AC power to the site is interrupted. These pumps are the first of the auxiliary equipment to be energized during a startup.
Sequence. Following shutdown of the unit, these pumps continue to run throughout the extensive cool down period and are the last of the auxiliary equipment to be stopped. The lube oil system is self-contained. After Lubricating and removing heat from the rotating equipment, oil is returned to the lube oil tank. It is cooled by oil-to-water heat exchangers as it is pumped from the tank and re-circulated. Various sensing devices are Included in the design to ensure adequate oil level in the tank, oil pressure, and oil temperature.
All pumps have a check valve on the pump discharge line so that oil does not flow into the tank through a pump, which is not in service. Oil tank temperature is indicated by a thermometer on the side of the tank. Thermocouples connected to the control panel indicate lube oil temperature in the bearing header. Thermocouples in the bearing drains are also wired to the turbine control panel for monitoring. A bearing header oil sampling port is located upstream of VPR2-1.
For turbine starting, a maximum oil viscosity of 800 SUS (173 centistokes) is specified for reliable operation of the control system and for bearing lubrication. Temperature switch 26QN-1 or LT-OT-4A prevents turbine startup if the temperature of the lubricant decreases to a point where oil viscosity exceeds 800 SUS (173 centistokes).
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