DLN1A
Short Description
G...
Description
Scene 9A21
Graphic Description Menu (9100): 4 zones
9A2.0A1
Animation 9101: Simplified DLN 1 Gas Fuel System Diagram
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Graphic 9103: SRV/GCV Assembly
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Animation 9104:
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Animation 9105:
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Graphic 9106: SRV/GCV in Gas Fuel Module Graphic 9107
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Animation 2518:
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Graphic 9108:
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Animation 2518:
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Graphic 9109:
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Animation 9020:
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Graphic 9021: location of Gas Fuel Vent Valve Animation 9022:
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Graphic 9112:
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Animation 9113:
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Graphic 9114:
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Graphic 9116:
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Graphic 9117:
Text DLN 1 Gas Fuel System is divided into two topics. “Key Components” identifies the major components of a DLN 1 Gas Fuel System and explores the functions of the system components. “System Operation” illustrates the modes of operation of a DLN 1 combustor and traces the flow of gas fuel during normal operation of the DLN 1 Gas Fuel System. Key components of the DLN 1 Gas Fuel System include: the Stop/Speed Ratio and Gas Control Valve Assembly; SRV Servo Valve; SRV Dump Valve; GCV Servo Valve; Gas Fuel Vent Solenoid Valve; Gas Fuel Pressure Transmitters; Gas Fuel Splitter Valve; Gas Fuel Transfer Valve; and DLN 1 Combustor. The Stop/Speed Ratio and Gas Control Valve Assembly consists of two independently operated valves combined into one assembly. Both the Stop/Speed Ratio and Gas Control Valves are single-acting, electro-hydraulicly operated valves. The major components of the Stop/Speed Ratio Valve are the: valve inlet; valve stem; LVDTs; hydraulic cylinder; SRV Dump Valve; and SRV Servo Valve. The major components of the Gas Control Valve are the: valve outlet; valve stem; LVDTs; hydraulic cylinder; and GCV Servo Valve. The Stop/Speed Ratio and Gas Control Valve Assembly is located in the Gas Fuel Module. The Stop/Speed Ratio Valve Servo Valve is a four way, infinite position servo, mounted in the hydraulic position servo assembly. It is enclosed by a rugged steel cover box to protect it from damage. The major parts of a typical servo valve are the torque motor, motor armature, jet tube, spool valve, force feedback spring, and fail-safe bias spring. The Gas Control Valve Servo Valve is a four-way, infinite position servo, mounted in the hydraulic position servo assembly. It is enclosed by a rugged steel cover box to protect it from damage. The major parts of a typical servo valve are the torque motor, motor armature, jet tube, spool valve, force feedback spring, and fail-safe bias spring. The Stop/Speed Ratio Valve Dump Valve is mounted on the hydraulic cylinder housing for the Stop/Speed Ratio Valve. The main parts of the SRV Dump Valve are the: valve piston; piston porting sleeve; spring seat; spring; and spring retainer. The Gas Fuel Vent Valve is installed in the vent piping from the casing of the Stop/Speed Ratio and Gas Control Valve Assembly. The gas fuel vent is a normally open, solenoid-operated valve. The main parts of the vent solenoid valve are the: coil; plunger and stem assembly; piston; valve disc; and insert. The Gas Fuel Splitter Valve is a three-way valve actuated by a hydraulic cylinder. The splitter valve is located in the Gas Fuel Module. The main parts of the Gas Fuel Splitter valve are the: primary splitter valve; secondary splitter valve; hydraulic cylinder; splitter valve servo valve; and splitter valve primary and secondary LVDTs. The Gas Fuel Transfer Valve is a three-way valve actuated by a hydraulic cylinder. The transfer valve is located in the Gas Fuel Module. The DLN 1 combustor is a two-stage premixed combustor. The fuel injection system is designed to support combustion in either the primary zone, secondary zone, or both, depending on the mode of operation. The primary fuel injection system delivers fuel to the primary combustion zone. It consists of five to six nozzles that can be of the dual fuel type. These nozzles provide a stable flame from ignition to part load operation, while providing a good mixing distribution in the primary zone.
Scene 9A2.A93
Graphic Description Graphic 9118:
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Graphic 9119:
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Graphic 9119A:
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Gas Fuel Pressure Transmitters Graphic 9023 or 9111: Animation 9024: Graphic 9132:
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Graphic 9134
9A2.C1C1
Graphic 9135:
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Graphic 9137:
9A2.C1E2
Graphic 9139:
9A2.C1F1
Graphic 9140: 96SR-1, 2 Graphic 9141 96GC-1, 2
9A2.C1H2
Graphic 9143: VH5-1
9A2.C1I1
Graphic 9144:
90SR-1
9A2.C1J1
Graphic 9145:
65GC-1
Text The secondary fuel nozzle delivers fuel to the secondary zone. The secondary nozzle is inserted into the centerbody of the liner, and may have a secondary flame detector mounted on it to monitor flame conditions in the secondary zone. Secondary fuel flows through the premix nozzles, which are pegs attached to the secondary nozzle. Some secondary fuel also flows through the subpilot, which is located at the tip of the secondary nozzle. Tertiary fuel (also called transfer fuel) flows through a set of holes around the subpilot. Stop/Speed Ratio and Gas Control Valves- Components Three Gas Fuel Pressure Transmitters are installed in the piping on the gas fuel discharge side of the Stop/Speed Ratio Valve. The main parts of a typical pressure transmitter are the sensing element and printed circuit boards. These are assembled in a metal housing. 96FG-2A, 2B, 2C are the Gas Fuel Pressure Transmitters. Each transmitter produces a DC output directly proportional to the gas fuel pressure between the Stop/Speed Ratio and Gas Control Valves. • 20VG-1 is the Gas Fuel Vent Solenoid Valve. During normal turbine operation, 20VG-1 is energized to close the gas fuel vent. • When the turbine is shut down, 20VG-1 is de-energized. This vents to the atmosphere any gas fuel that might accumulate between the Stop/Speed Ratio Valve and the Gas Control Valve. 63FG-3 is the Gas Fuel Pressure Switch. This switch activates an alarm if the gas fuel supply pressure drops below 285 psi (19.7 bar). • VSR-1 is the Stop/Speed Ratio Valve. VSR-1 provides a regulated inlet pressure, called P2 pressure, for the Gas Control Valve. The position of VSR-1 based on turbine speed. • The Stop/Speed Ratio Valve also stops the flow of fuel to the turbine during an emergency trip or a normal shutdown. • VGC-1 is the Gas Control Valve. VGC-1 provides the final precise metering of gas fuel to the turbine. • The position of the Gas Control Valve is a linear function of the called-for fuel flow signal generated by the control system. VGC-1 is modulated as necessary to either maintain the turbine speed or to satisfy the load requirement when the generator is connected to the power grid. 96SR-1, 2 are the Stop/Speed Ratio Valve Linear Variable Differential Transducers, or LVDTs. The LVDTs provide an analog AC feedback to the control system. The feedback signal is directly proportional to the position of the Stop/Speed Ratio Valve. 96GC-1, 2 are the Gas Control Valve Linear Variable Differential Transducers, or LVDTs. The LVDTs provide an analog AC feedback to the control system. The feedback signal is directly proportional to the position of the Gas Control Valve. • VH5-1 is the Stop/Speed Ratio Valve Dump Valve. The dump valve is operated by the Trip Oil System. When trip oil is at normal pressure, the dump valve is maintained in a position that allows 90SR-1 to operate the hydraulic cylinder of the Stop/Speed Ratio Valve. • During a normal shutdown, or when the turbine is tripped during an emergency condition, trip oil pressure at the dump valve is relieved. As a result, VH5-1 dumps hydraulic oil in the actuating cylinder of the Stop/Speed Ratio Valve to drain. The closing spring shuts VSR-1 and all fuel flow to the turbine is stopped. 90SR-1 is the SRV Servo Valve. This servo valve controls the flow of hydraulic oil to and from the hydraulic actuator of the Stop/Speed Ratio Valve. 65GC-1 is the GCV Servo Valve. This servo valve controls the flow of hydraulic oil to and from the
Scene
Graphic Description
9A2.C1K1
Graphic 9146:
FH7-1
9A2.C1L1
Graphic 9147:
VGA-1 (see NOX88)
9A2.C2A1
Graphic 9151 VGS-3
9A2.C2A2
Graphic 9152: VGS-1 Graphic 9153: VGS-2 Graphic 9154: 96GS-1, 2. 96GS-1
Text hydraulic actuator of the Gas Control Valve. FH7-1 is the Gas Fuel Servo Hydraulic Supply Filter. It prevents contaminants from entering the servo valves 90SR-1 and 65GC-1. VGA-1 is the Stop/Speed Ratio and Gas Control Valve Assembly. VGA-1 regulates gas fuel input to the combustors in accordance with the speed and load requirements of the gas turbine.
Gas Fuel Splitter and Transfer Valves
9A2.C2A3 9A2.C2B1 9A2.C2C1 9A2.C2D1 9A2.C2E1
9A2.C2F1 9A2.C2G1 9A2.C2H1 9A2.C2I1
Graphic 9155: 96GD-1, 2 Graphic 9156: VGDGraphic 9157: 20TS-1, Graphic 9158: 65GS-1 Graphic 9159: 65GD-1 Graphic 9160: FH14Graphic 9161 FH15-1
VGS-3 is the Gas Fuel Splitter Valve. The splitter valve takes the total fuel flow regulated by the Gas Control Valve and divides it between the primary and secondary fuel paths. The Gas Fuel Splitter Valve consists of VGS-1 and VGS-2, which operate simultaneously. VGS-1 is the Primary Splitter Valve. The primary splitter valve supplies fuel to the primary gas fuel manifold. VGS-2 is the Secondary Splitter Valve. The secondary splitter valve supplies fuel to the Gas Fuel Transfer Valve. The Gas Fuel Splitter Valve is equipped with two LVDTs, 96GS-1, 2. 96GS-1 produces a feedback signal proportional to the position of the primary splitter valve. 96GS-2 produces a feedback signal proportional to the position of the secondary splitter valve. Two redundant LVDTs 96GD-1, 2 are mounted on the Gas Fuel Transfer Valve to provide valve position feedback for closed loop control. VGD-1 is the Gas Fuel Transfer Valve. The transfer valve regulates the gas fuel flow to both the Secondary and Transfer Gas Fuel Manifolds. The Gas Fuel Splitter Valve is equipped with two Trip Solenoid Valves, 20TS-1, 2. Certain operational situations, such as load rejection, require the splitter valve to be tripped to either the full primary or full secondary position. The control system energizes 20TS-1 if the 100% primary position is required. 20TS2 is energized if the 100% secondary position is required. 65GS-1 is the Gas Fuel Splitter Valve Servo Valve. The servo valve is able to position the splitter valve in an infinite number of positions, from zero stroke to 100% stroke. 65GD-1 is the Gas Fuel Transfer Valve Servo Valve. The servo valve is able to position the transfer valve in an infinite number of positions, from zero stroke to 100% stroke. The Hydraulic Supply Filter for the Gas Fuel Splitter Valve, FH14-1, protects the servo valve and solenoid valves from dirt in the hydraulic system. The Hydraulic Supply Filter for the Gas Fuel Transfer Valve, FH15-1, protects the servo valve from dirt in the hydraulic system.
Gas Fuel Purge Valves 9A2.C3A1
Graphic 9171: VPR54-1
9A2.C3B2
Graphic 9173: 20PG-3, 4
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Graphic 9174: 33PG-5, 6
The Purge Control Valve Air Pressure Regulator, VPR54-1, regulates atomizing air at a safe operating pressure for VA13-3 and VA13-4. This avoids hardware damage when the gas fuel purge solenoid valves are energized. • 20PG-3, 4 are the Gas Fuel Purge Solenoid Valves. The solenoid valves are normally deenergized. This vents the air from the pneumatic actuators of VA13-3, 4, keeping the purge valves open. • The control system energizes the purge solenoid valves prior to opening the transfer valve. This applies atomizing air from VPR54-1 to the pneumatic actuators of VA13-3, 4, closing the purge valves. Purge valve VA13-3 is equipped with two limit switches that inform the control system of the valve's position. 33PG-5 is closed when the purge valve is closed and 33PG-6 is closed when the purge valve is
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Graphic Description
9A2.C3D1
Graphic 9175: 33PG-7, 8
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Graphic 9177: 20 VG-3
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Graphic 9179: VA13-3, 4
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Graphic 9179A: 63PG
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Graphic 9120:
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Graphic 9120A: Caution screen
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Animation 9121:
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Animation 9122:
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Animation 9123:
9A2.B41
Animation 9124:
9A2.D01
Graphic 9180: simplified diagram of DLN 1 System; see NOX28A Animation 9181: ; refer to NOX28B
Text open. Purge valve VA13-4 is equipped with two limit switches that inform the control system of the valve's position. 33PG-7 is closed when the purge valve is closed and 33PG-8 is closed when the purge valve is open. • 20VG-3 is a Gas Fuel Vent Solenoid Valve installed in the piping between purge valvesVA13-3, 4. 20VG-3 is normally de-energized (closed). • Prior to opening the transfer valve, the control system energizes 20VG-3. This opens 20VG-3 and vents the short section of pipe between VA13-3 and VA13-4. • The Gas Fuel Purge Valves VA13-3, 4 are normally open air-operated valves. They allow cooling and sealing air to purge the transfer ports in the secondary fuel nozzles during primary, lean-lean, and premix operation. • The purge valves are closed when the purge solenoid valves are energized by the control system. This shuts off purge air during the transfer phase of the secondary and premix transfer modes. 63PG-2 is the Gas Fuel Purge Pressure Switch, connected to the short section of pipe between the purge valves. 63PG-2 alerts the control system if it senses excessive pressure when the vent line should be open.
DLN-1 Gas System Operation There are four basic modes for distributing gas fuel to a DLN 1 Combustor. They are the primary, leanlean, secondary, and premix modes of operation. Typical values for unit speed, load, and temperature are used in this lesson. Refer to the control specifications for the correct operational parameters for a specific gas turbine. The first mode of distributing gas fuel to a DLN 1 combustor is the primary mode. Primary operation occurs from ignition to full speed, and continues from no load to approximately 35% load, or a combustion reference temperature of about 1600° F. Note that 100% of the fuel entering the combustor is admitted through the primary nozzles. The next mode, lean-lean, occurs from approximately 35% to 70% load, and a combustion reference temperature range from 1600° F to 1875° F. Fuel is supplied to, and combustion is taking place in, both the primary and secondary zones. Approximately 70% of the fuel being supplied to the combustor is delivered to the primary nozzles, while the remaining 30% is delivered to the secondary nozzles. The secondary mode occurs when the load is increased and the combustion reference temperature is raised to approximately 1875° F. At this point, all fuel is admitted to and burned in the secondary zone. The secondary mode is a transitory mode used to extinguish the flame in the primary zone by delivering no fuel to the primary nozzles and all of the fuel to the secondary nozzles. This mode prepares the combustor for premix operation. In the premix mode, fuel is delivered to both the primary and secondary zones. About 83% of the fuel is mixed with air in the primary zone, but combustion only occurs in the secondary zone. This premixing of fuel and air reduces the exhaust emissions. Typically, the premix mode occurs from 70% to 100% load, or at combustion reference temperatures above 1875° F.
DLN-1 Gas Operation 9A2.D02
This sequence illustrates the operation of the Gas Fuel System from startup through base load for a DLN 1 machine. Prior to startup, gas fuel is present up to the Stop/Speed Ratio Valve. When the control system gives the signal to fire the unit, the Stop/Speed Ratio and Gas Control Valves open and fuel flows to the combustors. From startup to about 35% load, or a combustion reference
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Graphic Description
9A2.D11
Animation 9182:
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Animation 9183:
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Animation 9184:
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Animation 9185
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Animation 9186:
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Animation 9187:
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Animation 9188:
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Animation 9189:
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Graphic 9189A: Caution Screen
9B21
Menu 9400: 4 zones
Text temperature of 1600º F, fuel flows only to the primary nozzles. This is the primary mode. The lean-lean mode of operation begins at a combustion reference temperature of about 1600º F. The Gas Fuel Splitter Valve opens allowing about 30% of the fuel to flow to the secondary nozzle while the remainder is burned in the primary zone of each combustor. The transfer valve is closed directing all of its fuel to the secondary manifold. When a system has no inlet bleed heat, the lean-lean mode occurs from approximately 35% to 70% load which corresponds to a combustion reference temperature of about 1600º F to 1875º F. The secondary mode begins when the combustion reference temperature reaches 1875º F. The fuel gas purge valves close to prevent gas from back-feeding into the compressor discharge casing. It is critical to prevent this back-feeding because combustion could take place in the compressor discharge casing, causing severe damage to the turbine. Once the purge valves are closed, the control system opens the Gas Fuel Transfer Valve and the splitter valve increases the quantity of gas supplied to the transfer valve. The transfer valve supplies a portion of the gas fuel to the transfer ports in the secondary fuel nozzles. Notice that an elapsed time of 12 seconds has occurred in this phase of the secondary mode. The splitter valve continues to open until 100% of the gas flow is supplied to the secondary zone. The transfer valve opens to approximately 83%. This causes the primary zone to flame out, while creating a large and stable diffusion flame in the secondary zone. When the primary flame detectors sense the loss of flame in the primary zone, the splitter valve starts to close allowing gas to enter the primary zone. The transfer valve maintains its position to ensure flame stability. Fuel is now entering the primary zone, but is being burned in the secondary zone. To ensure flame stability throughout the remainder of the transfer, the transfer valve opens to 100%. The splitter valve begins to close forcing more fuel into the primary zone, while the transfer valve remains at 100% to maintain flame stability and combustion in the secondary zone. Once the splitter valve has been positioned to supply about 87% of its fuel to the primary zone, the transfer to premix operation is almost complete. In order to complete the secondary mode and completely transfer to the premix mode, the transfer valve is closed, diverting gas fuel from the transfer ports to the secondary nozzle. In doing so, the secondary zone becomes essentially a premix zone with a small amount of gas burning in a diffusion flame from the subpilot. The premix mode of operation occurs from approximately 70% to 100% load for a unit not using inlet bleed heat. This correlates to a combustion reference temperature range of about 1920º F to 2350º F. Due to the fact that premixed combustion is taking place in both the primary and secondary zones, peak flame temperatures are lower and therefore NOx emissions are lower. Please note! Approximate values have been described throughout this lesson. The actual combustion reference temperatures used for each mode can be found in your unit's control specifications. Due to the fact that each machine has its own characteristics, during the initial startup these values may have to be adjusted by a qualified controls engineer to optimize your unit's performance.
DLN-1 Liquid Fuel System DLN 1 Liquid Fuel System is divided into four topics. “Key Components” identifies the major components of a DLN 1 Liquid Fuel System. “Liquid Fuel Modes” illustrates the normal operation of a DLN 1 combustor. “Component Functions” uses the Schematic Piping Diagrams of the DLN 1 Liquid Fuel System to explore the functions of the system components. “System Operation” traces the flow of liquid fuel during normal operation of the DLN 1 Liquid Fuel System. We suggest you begin with “Key Components.”
Scene 9B2.0A1
Graphic Description Animation 9401:
9B2.A11 9B2.A12
Graphic 9313: Liquid Fuel Stop Valve Animation 9314:
9B2.A13 9B2.A21
Graphic 9315: Graphic 9316:
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Animation 9317:
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Graphic 9318: Graphic 9319: fuel pump Graphic 9320: Graphic 9321: Graphic 9322: Graphic 9323: flow divider
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Graphic 9324: flow selector Graphic 9325: Graphic 9116:
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Graphic 9117:
9B2.A53
Graphic 9118:
9B2.A54
Animation 9402A:
9B2.C1A1
Graphic 9412: FH3-1 Graphic 9413: servo valve Graphic 9415: 63LF-1
9B2.C1B1 9B2.C1C2
9B2.C1D1
Graphic 9416:
Bypass Valve
Text Key components of the DLN 1 Liquid Fuel System include the: Liquid Fuel Stop Valve; Liquid Fuel Bypass Valve; Liquid Fuel Pump; Flow Divider; and DLN 1 Combustor. The Liquid Fuel Stop Valve is a hydraulically operated, two-position, venturi-type, valve-and-seat assembly. The main parts of the Liquid Fuel Stop Valve are the: closing spring; spring seat; valve disc; valve seat; valve stem; actuator rod; and hydraulic cylinder. The Liquid Fuel Stop Valve is mounted on the Accessory Base Module. The Liquid Fuel Bypass Valve is an electro-hydraulically operated valve, connected between the inlet and discharge sides of the Liquid Fuel Pump. The bypass valve is an assembly consisting of a: hydraulic supply filter; hydraulic cylinder; actuator rod; valve position indicator; valve stem; and valve body. The Liquid Fuel Bypass Valve is mounted on the Accessory Base Module. The Liquid Fuel Pump is a positive displacement, screw-type pump, driven by the Accessory Drive Gear. The fuel pump contains two pairs of opposed screws. Each pair of screws conveys liquid fuel to the center of the pump where the discharge port is located. The Liquid Fuel Pump is mounted on the Accessory Base Module. The flow divider is a continuous-flow, free-wheeling device consisting of ten gear pump elements in a circular arrangement. A single timing gear maintains true synchronous speed among the gear pump elements. A 12-position selector valve and pressure gauge assembly is located at the output of the flow divider. This allows manual monitoring of fuel oil pressure in a selected fuel nozzle inlet line. The flow divider is mounted on the Accessory Base Module. The DLN 1 combustor is a two-stage combustor. The fuel injection system is designed to support combustion in either the primary zone, secondary zone, or both, depending on the mode of operation. The primary fuel injection system delivers fuel to the primary combustion zone. It consists of five to six nozzles that can be of the dual fuel type. The secondary fuel nozzle delivers fuel to the secondary zone. The secondary nozzle is inserted into the centerbody of the liner, and may have a secondary flame detector mounted on it to monitor flame conditions in the secondary zone. This photo shows the end cover of a DLN 1 combustor configured for liquid fuel operation. The connections that are visible include: the liquid fuel distribution valve which feeds the primary zone; the liquid fuel connection to the secondary zone; the atomizing air connection; and the optional water injection connection. FH3-1 is the hydraulic oil supply filter for the Liquid Fuel Bypass Valve. The oil filter prevents particles in the hydraulic oil from affecting the normal operation of the bypass valve servo valve. 65FP-1 is the Liquid Fuel Bypass Valve Servo Valve. This servo valve controls the flow of hydraulic oil to and from the hydraulic actuator of VC3-1. • 63LF-1 is a differential pressure switch installed in parallel with the Low Pressure Liquid Fuel Oil Filter. • The differential pressure switch activates an alarm when the differential pressure across FF1-1 reaches 15 psi (103.4 kPa). This alerts the operator that the filter is getting plugged and that maintenance of the filter is required. VC3-1 is the Liquid Fuel Bypass Valve. VC3-1 meters the flow of fuel to the turbine by diverting excess
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Graphic Description
9B2.C1E2
Graphic 9418: 63LF-2
9B2.C1F1
Graphic 9419: FD1-1 Graphic 9420: FF1-1
9B2.C1G1 9B2.C1H2
Graphic 9422: VS1-1
9B2.C1I1
Graphic 9423:
9B2.C1J2
Graphic 9425: fuel pump
9B2.C1K1
Graphic 9426:
FF2-1
9B2.C1L1
Graphic 9427:
33FL-1
9B2.C1M1
Graphic 9428: pickups
magnetic speed
9B2.C2A1
Graphic 9431:
VCK1-1 to 10 (
9B2.C2C1
Graphic 9433:
33FK-1
9B2.C2D2
Graphic 9435: VH9-1
9B2.C2E1
Graphic 9436:
9B2.C2F1
Graphic 9437: FH4-2 Graphic 9438:
9B2.C2G1
20CF-1
VPR53-2
Text fuel delivered by the Liquid Fuel Pump back to the pump inlet. • 63LF-2 is a differential pressure switch installed in parallel with the High Pressure Liquid Fuel Oil Filter. • The differential pressure switch activates an alarm when the differential pressure across FF2-1 reaches 15 psi (103.4 kPa). This alerts the operator that the filter is getting plugged and that maintenance of the filter is required. The Liquid Fuel Flow Divider, FD1-1, distributes an equal amount of fuel oil to each of the turbine combustors. The Low Pressure Liquid Fuel Filter, FF1-1, prevents any contaminants that might be in the fuel system from passing through and interfering with the proper operation of the Liquid Fuel Stop Valve and the Liquid Fuel Pump. • VS1-1 is the Liquid Fuel Stop Valve. This stop valve shuts off the supply of liquid fuel to the turbine during normal and emergency shutdowns. • During normal operation of the turbine, the Liquid Fuel Stop Valve is held open by high pressure hydraulic oil. 20CF-1 is the Liquid Fuel Pump Clutch Solenoid. 20CF-1 is energized at the appropriate point in the turbine startup sequence. This engages the clutch allowing the Accessory Drive Gear to drive the Liquid Fuel Pump. • The Liquid Fuel Pump, PF1-1, is driven by the Accessory Drive Gear. Therefore, the speed of the fuel pump is directly proportional to turbine speed. • The discharge flow of the Liquid Fuel Pump at any given turbine speed is greater than the turbine combustion requirement at that speed. FF2-1 is the High Pressure Liquid Fuel Filter. This filter is a backup device to protect the flow divider and components downstream from being damaged by contaminants. The Liquid Fuel Stop Valve Limit Switch, 33FL-1, communicates to the control system whether the Liquid Fuel Stop Valve is open or closed. It will not allow the liquid fuel pump clutch to engage unless the stop valve is open. The Liquid Fuel Flow Divider is equipped with three magnetic speed pickups, 77FD-1, 2, 3. Each of these devices produces a feedback signal that is proportional to the rate of fuel flow to the combustor fuel nozzles. This feedback signal is used to control the position of the Liquid Fuel Bypass Valve. The Liquid Fuel Nozzle Check Valves, VCK1-1 to 10, are installed in the fuel piping to the primary and secondary nozzles. The check valves provide a clean cutoff of fuel during shutdown. 33FK-1 is a limit switch that provides the control system with the position of the Multi-Port Fuel Isolation Valve. 33FK-1 is closed when VH9-1 is closed, and is open when VH9-1 is open. • The Multi-Port Fuel Isolation Valve, VH9-1, has one port for each combustor. When VH9-1 is closed, it allows liquid fuel to flow only to the primary fuel nozzles. • When VH9-1 is open, it allows the flow of liquid fuel to be split between the primary and secondary fuel nozzles. VPR53-2 is the Hydraulic Oil Pressure Regulator. To avoid hardware damage, VPR53-2 regulates the strength with which the Multi-Port Fuel Isolation Valve is opened and closed. FH4-2 is the hydraulic oil supply filter for the Multi-Port Fuel Isolation Valve Solenoid Valve. The filter prevents contaminants from entering solenoid valve 20FK-1. 20FK-1 is the Multi-Port Fuel Isolation Valve Solenoid Valve. When 20FK-1 is activated by the control
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Graphic Description
9B2.C2H2
Graphic 9440: 20FK-1
9B2.C2I2
Graphic 9442: VA17-5
9B2.B01 9B2.B02 9B2.B11
Graphic 9403: Graphic 9120A: Caution screen "Refer to Control Specifications . . . " Animation 9404:
9B2.B12
Animation 9405:
9B2.B21
Animation 9406:
9B2.B22
Animation 9407
9B2.D01
Graphic 9450: use NOX99A
9B2.D02
Animation 9450A:
9B2.D11
Animation 9451:
9B2.D12
Animation 9452:
9B2.D21
Animation 9453:
Text system, it directs hydraulic oil to either open or close the Multi-Port Fuel Isolation Valve. • VA17-5 is the Exhaust Plenum False Start Drain Valve. False start drain valves are spring-loaded to the open position, and are closed during turbine startup by compressor discharge air. • If an attempt to start the turbine is unsuccessful, any accumulation of combustible fuel oil in the exhaust plenum is drained through VA17-5. • VA17-1 is the Combustion Wrapper False Start Drain Valve. False start drain valves are springloaded to the open position, and are closed during turbine startup by compressor discharge air. • If an attempt to start the turbine is unsuccessful, any accumulation of combustible fuel oil in the combustion wrapper is drained through VA17-1.
DLN-1 Gas System Operation There are two modes of distributing liquid fuel to a DLN1 combustor: primary; and lean-lean. Typical values for unit speed, load, and temperature are used in this lesson. Be sure to refer to the control specifications for the correct operational parameters for a specific gas turbine. In the primary mode all fuel is admitted through the primary nozzles in each combustor. Liquid fuel burns in the primary zone as a diffusion flame. The primary mode of operation ranges from ignition to approximately 35% load or a combustion reference temperature of approximately 1600° F. During the lean-lean mode, a portion of the liquid fuel is diverted to the secondary nozzles and combustion occurs in both the primary and secondary zones. Diverting some of the total fuel flow into the secondary zone is necessary to prevent the primary zone flame from impinging on and damaging the combustion liner venturi and centerbody. The lean-lean mode of operation occurs from approximately 35% to 100% load. A 50/50 primary to secondary fuel split will remain constant throughout the load range.
DLN-1 Liquid Fuel Operation In this sequence you will see how the DLN 1 Liquid Fuel System functions from startup through base load. Prior to firing the unit, liquid fuel is present up to the Liquid Fuel Stop Valve. During the startup sequence, but before ignition, the Atomizing Air System is activated and atomizing air flows to the turbine combustors. When the control system gives the signal to fire the unit, the Liquid Fuel Stop Valve opens and fuel flows to the fuel pump. The fuel pump is engaged by the solenoid clutch. At this point, the bypass valve is fully open allowing full recirculation of the liquid fuel. During the primary mode, the bypass valve slowly closes to force fuel to the flow divider. The flow divider distributes the fuel to each combustor. From startup to about 50% load or a combustion reference temperature of about 1600° F, the Multi-Port Fuel Isolation Valve is closed and fuel flows only to the primary nozzles. At a combustion reference temperature of about 1600° F, the fuel system switches to the lean-lean mode of operation. The Multi-Port Fuel Isolation Valve opens allowing about 50% of the fuel to flow to the secondary nozzles while the remainder flows to the primary nozzles. The liquid fuel system remains in the lean-lean mode throughout full load operation.
DLN-1 Dual Fuel Operation 9C21
Menu 9620: 3 zones
DLN 1 Dual Fuel System is divided into three topics. "Dual Fuel Combustor" describes the unique features of a DLN 1 combustor configured for dual fuel operation. "Dual Fuel Purge" explores the functions of the purge system devices. "Fuel Transfer Operation" illustrates a transfer from gas fuel operation to liquid fuel
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Graphic 9631:
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Graphic 9634: VA19-2
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Graphic 9646: VA13-1, 2
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Graphic 9649: text box on schematic with this message Graphic 9635: purge check valves
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Graphic 9635A: 20PL-1 Graphic 9636: 20PL-2
limit switches
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Text operation. A gas turbine with DLN 1 dual fuel capability requires a Dual Fuel Purge System. During liquid fuel operation, the gas fuel passages in the primary nozzles are purged with compressor discharge air. During gas fuel operation, the liquid fuel passages in the primary and secondary nozzles are purged with atomizing air. This diagram illustrates the end cover of a DLN 1 combustor configured for dual fuel operation. There are connections for: primary gas fuel; primary liquid fuel; secondary gas fuel; secondary liquid fuel; atomizing air; transfer gas fuel; secondary water injection; and primary water injection. The details of a primary nozzle are shown here. During gas fuel operation, natural gas is fed through manifolds in the end cover and enters the primary zone through metering holes in the gas tip. During liquid fuel operation, fuel oil is fed through the oil tip and is injected into the primary zone. Atomizing air is fed through the oil tip and impinges on the stream of fuel oil, breaking it up into a mist of fine particles to optimize combustion. The details of the secondary nozzle are illustrated here. During gas fuel operation, secondary gas is delivered to the premix pegs and the subpilot. Transfer gas exits from the end of the secondary nozzle through the transfer ports. During liquid fuel operation, fuel oil is fed through the oil tip and is injected into the secondary zone. Water may be mixed with the fuel oil at the outlet of the oil tip if the water injection option is available. • VA19-2 is the Secondary Liquid Fuel Nozzle Purge Valve. When VA19-2 is actuated, it allows atomizing air to purge the oil tubes in the secondary fuel nozzles. • When VA19-2 is deactivated, it vents to a telltale leak off. This allows an operator to check for any liquid fuel that has leaked past the purge air check valves into the purge air manifold. Purge valve VA13-1 is equipped with two limit switches that inform the control system of the valve's position. 33PG-1 is closed when the purge valve is closed and 33PG-2 is closed when the purge valve is open. • The Primary Gas Fuel Purge Valves VA13-1, 2 are normally closed, air-operated valves. • The purge valves open when solenoid valves 20PG-1, 2 are energized during liquid fuel operation. Compressor discharge air then purges the primary gas fuel passages to prevent coking of the nozzle orifices. When the Gas Fuel Vent Solenoid Valve 20VG-2 is energized by the control system, it vents the short piece of purge line between VA13-1 and VA13-2. Purge valve VA13-2 is equipped with two limit switches that inform the control system of the valve's position. 33PG-3 is closed when the purge valve is closed and 33PG-4 is closed when the purge valve is open. These components are part of the Transfer Gas Fuel Purge System, used to cool the transfer portion of the secondary nozzle. Refer to the Gas Fuel System unit of this lesson to learn about these components. The Secondary Liquid Fuel Nozzle Purge Check Valves, VCK2-11 to 20, are installed in the oil fuel lines to each secondary fuel nozzle. These check valves prevent oil from entering the purge air manifold when the turbine is operating on liquid fuel. 20PL-1 is the Liquid Fuel System Primary Purge Solenoid Valve. When activated by the control system, this solenoid valve actuates VA19-1. 20PL-2 is the Liquid Fuel System Secondary Purge Solenoid Valve. When activated by the control system, this solenoid valve actuates VA19-2.
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Graphic Description Graphic 9638: VA19-1
Text VA19-1 is the Primary Liquid Fuel Nozzle Purge Valve. When VA19-1 is actuated, it allows atomizing air to purge the oil tubes in the primary fuel nozzles. • When VA19-1 is deactivated, it vents to a telltale leak off. This allows an operator to check for any liquid fuel that has leaked past the purge air check valves into the purge air manifold. Graphic 9639: check valves The Primary Liquid Fuel Nozzle Purge Air Check Valves, VCK2-1 to 10, are installed in the oil fuel lines to the primary fuel nozzles. These check valves prevent oil from entering the purge air manifold when the turbine is operating on liquid fuel. Graphic 9640: VPR54-1 The Purge Control Valve Air Pressure Regulator, VPR54-1, regulates atomizing air at a safe operating pressure for VA19-1 and VA19-2. This avoids hardware damage when the liquid fuel purge solenoid valves are energized. Graphic 9641: 63PG-1 63PG-1 is the Primary Gas Fuel Purge Pressure Switch, connected to the short section of pipe between the gas fuel purge valves. This pressure switch alerts the control system if there is excessive pressure in the vent piping when the vent line should be open. Graphic 9643: Build on previous, add • 20PG-1, 2 are the Primary Gas Fuel Purge Solenoid Valves. The solenoid valves are normally de2nd bullet energized. This vents the air from the pneumatic actuators of the purge valves and keeps the purge valves closed. • When energized by the control system, the solenoid valves allow atomizing air to open the purge valves, VA13-1, 2. DLN-1 Dual Fuel System Operation Animation 9650: DLN 1 gas fuel, primary When operating a turbine equipped with a dual fuel system, the turbine is able to start on either fuel and mode switch to the alternate fuel after full speed has been attained. In this example the turbine is operating on gas fuel at full speed no load. The gas fuel system is in the primary mode. Animation 9651: DLN 1 liquid fuel During operation on gas fuel, the Liquid Fuel Stop Valve is closed and the fuel oil tubes in the primary and animation secondary fuel nozzles are being purged with atomizing air. The Gas Fuel Primary Purge Valves are closed but the transfer ports in the secondary fuel nozzles are being purged with compressor discharge air. Animation 9652: liquid fuel purge shuts When the control system gets a signal to transfer to liquid fuel, the Primary and Secondary Liquid Fuel off, liquid fuel flow begins Purge Valves are closed. The Liquid Fuel Stop Valve opens and the Liquid Fuel Pump is engaged. As liquid fuel flows to the combustors the amount of gas fuel flow is decreased in order to maintain stable operating parameters during the transfer. Animation 9653: show primary gas fuel Once the transfer to liquid fuel operation is complete, the Stop/Speed Ratio Valve in the gas fuel system is purge closed and the Primary Gas Fuel Purge Valve opens. Throughout liquid fuel operation, the primary and transfer gas fuel nozzles are purged with compressor discharge air to prevent the nozzles from fouling. •
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Graphic 9191:diagram of splitter valve with LVDTs called out Graphic 9192:diagram of DLN 1 combustor Graphic 9193:diagram of VGA-1
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Graphic 9655: DLN 1 end cover diagram (see A9622)
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DLN-1 Review Questions The arrows in this diagram are pointing to what devices? Where is gas fuel burned during premix operation in a DLN 1 combustor? During a normal shutdown or an emergency trip, all oil in the hydraulic actuator of the Stop/Speed Ratio Valve is dumped to drain by which device? During what mode of operation is gas fuel burned in both the primary and secondary zones of a DLN 1 combustor? components and operation of the DLN 1 Dual Fuel System. What connection on the DLN 1 dual fuel combustor is for secondary gas fuel?
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Graphic 9657: liquid fuel half of DLN 1 Dual Fuel Purge System schematic Graphic 9464
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In the DLN 1 Dual Fuel System during gas fuel operation, the liquid fuel passages in the primary and secondary fuel nozzles are purged with: What device is the Primary Liquid Fuel Nozzle Purge Valve? Liquid fuel is burned in what zone, or zones, during the lean-lean mode of a DLN 1 combustor? Which liquid fuel system component contains a closing spring that enables it to shut off all fuel flow during an emergency shutdown? What are the liquid fuel modes of operation for a DLN 1 combustor?
Graphic 9461:) dwg. of system from A9401 Graphic 9462: DLN 1 combustor from A9118 Graphic 9463: photo from A9434 What is the DLN 1 liquid fuel system component in this photograph?
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