Dual-fuel switching and purging cooling system of gas turbine

Abstract

The utility model provides a dual-fuel switching and purging cooling system of a gas turbine, and aims to solve the problems that the dual-fuel switching fuel utilization rate of the gas turbine in the prior art is low, and fuel is unstable before and after switching. The device mainly comprises a combustion chamber unit, a gas fuel supply unit, a liquid fuel supply unit, an external gas source supply unit, an external water source supply unit and a gas compressor exhaust introduction unit, gas and liquid fuel are premixed and atomized through an external gas source respectively, pipelines before and after switching are purged, the safety and reliability of the fuel operation environment are ensured, gas and liquid fuel are reversely blown through exhaust of the gas compressor or introduction of inert gas, and the safety and reliability of the fuel operation environment are ensured. The cut-off gas fuel is discharged or the residual liquid fuel in the pipeline returns to the container, the liquid fuel pipeline is cooled through an external water source, blockage of the pipeline and the nozzle is prevented, and the problems that the dual-fuel switching fuel utilization rate of the gas turbine is low, and the fuel is unstable before and after switching are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of gas turbines, in particular to a dual-fuel switching and purging cooling system for gas turbines. Background Technique

[0002] The fuel supply responsible by the fuel system of a gas turbine is an important key technology. With the development of technology, the working environment of gas turbines is flexible and changeable, and the requirements for maintaining fuel parameters within a certain range are getting higher and higher. Under actual working conditions, a single fuel is difficult to maintain stable process parameters such as pressure, temperature, and flow rate within a range. Therefore, when one fuel cannot meet the system requirements, it is necessary to switch to another fuel for supplementary supply to enable the reliable operation of the gas turbine.

[0003] Enabling a gas turbine to use gaseous fuel and liquid fuel and being able to switch according to needs is a problem that must be overcome on the road of the development of fuel system technology; however, existing research has focused on fuel switching. For example, sensors are set for the control center to master parameter conditions. When switching between two fuels, manual judgment is made on whether the liquid pipeline or gas pipeline meets the switching conditions, but the impact of the working conditions in the pipeline on the fuel itself during fuel switching has not been considered. For example, when switching from natural gas fuel to fuel oil fuel, due to the relatively high working condition temperature, the temperature of the fuel oil pipeline is also high, which will cause the fuel oil fuel to be oxidized and sintered in the pipeline and adhere to the pipe wall, thereby greatly reducing the efficiency of the fuel after switching. Therefore, it is necessary to solve the problem of purging and cooling the pipeline during dual-fuel switching of gas turbines. Content of the Utility Model

[0004] This application aims at the above-mentioned disadvantages in the prior art and provides a dual-fuel switching and purging cooling system for gas turbines. Compared with the fuel supply of traditional systems, it can meet more working conditions, has stronger fuel supply stability, higher fuel utilization efficiency, and its system structure is simple, reliable, recyclable, can effectively reduce costs, and has wide application value.

[0005] The technical solution adopted by the utility model is as follows:

[0006] A dual-fuel switching and purging cooling system for gas turbines, which includes:

[0007] A combustion chamber unit, which is used to convert the chemical energy in the fuel into thermal energy to drive the turbine to do work, and has connecting pipes on both sides to connect fuels of different media;

[0008] A gaseous fuel supply unit, one end of which is connected to the outside as an inlet, and the other end is connected to one connecting pipe of the combustion chamber unit as an outlet, and is used to transport gaseous fuel to the combustion chamber;

[0009] A liquid fuel supply unit, with one end connected to the outside as an inlet and the other end connected to the connecting pipe at the other end of the combustion chamber unit, for delivering liquid fuel to the combustion chamber;

[0010] An external gas source supply unit, which is connected in parallel to the gas fuel supply unit and the liquid fuel supply unit. One side branch of the external gas source supply unit is connected to the middle and rear sections of the gas fuel supply unit to increase the intervention of the gas source to achieve fuel premixing and the back blowing and discharging of the gas fuel. The other side branch of the external gas source supply unit is connected to the middle and rear ends of the liquid fuel supply unit to increase the intervention of the gas source to achieve atomization of the liquid fuel and the back blowing of the liquid fuel;

[0011] An external water source supply unit, which is connected to the liquid fuel connecting pipe in front of the combustion chamber to cool down the pipeline before switching from gas fuel to liquid fuel;

[0012] A compressor exhaust gas introduction unit, which is connected to the liquid fuel connecting pipe to back blow the liquid fuel pipeline after switching from liquid fuel to gas fuel.

[0013] Further, the gas fuel supply unit successively includes a manual switch valve, a gas fuel filter, a gas fuel flow meter, a fuel premixing valve, an exhaust control valve, a gas fuel stop valve, a temperature sensor, a pressure sensor, a main fuel flow control valve, and a bypass fuel control valve. When the gas turbine is ignited, the main fuel flow control valve and the bypass fuel valve are opened. After the fuel is ignited, the bypass fuel valve is closed, and the fuel is supplied by the main fuel flow control valve. When there is too much gas fuel, the excess gas fuel is discharged by the exhaust control valve.

[0014] Further, the liquid fuel supply unit successively includes a pressure sensor, a gear pump, a liquid fuel filter, a liquid fuel stop valve, a liquid fuel flow meter, a liquid fuel check valve, a shunt valve, an auxiliary oil circuit flow meter, a main oil circuit check valve, and an auxiliary oil circuit check valve. The liquid fuel is configured to enter the liquid fuel pipeline through the gear pump, be filtered by the liquid fuel filter and pass through the liquid fuel stop valve, then be mixed and atomized with the gas supplied by the external gas source unit, and then enter the shunt valve through the flow meter and the check valve, and the shunt valve is adjusted by the parameters of the two flow meters, and finally enters the combustion chamber for combustion.

[0015] Further, the external gas source supply unit successively includes an external gas source switch, an external gas source filter, and a three-way valve.

[0016] Further, the external water source supply unit includes an external water source and an external water source check valve, and the external water source check valve is connected before switching from gas fuel to liquid fuel.

[0017] Further, the compressor exhaust gas introduction unit includes a heat exchanger and two groups of backflush control valves provided on the liquid fuel pipeline.

[0018] Further, the gas source of the compressor exhaust gas is an inert gas.

[0019] The beneficial effects of the present utility model are as follows:

[0020] Compared with the prior art:

[0021] 1) When the fuel system of the present utility model is operating, it is not a traditional single fuel supply, but a combined supply of gaseous fuel and liquid fuel. When the gaseous fuel is insufficient to support the supply requirement, the system switches to liquid fuel supply. Similarly, when the liquid fuel is insufficient, it switches to gaseous fuel. This can effectively meet the supply requirements of various working conditions, ensure the stability of fuel supply, and effectively prevent the operation interruption caused by the gas turbine tripping or even shutting down.

[0022] 2) When the fuel system of the present utility model switches from gaseous fuel to liquid fuel, before the switch, water is introduced from an external water source into the liquid fuel pipeline near the combustion chamber to cool the liquid fuel pipeline, effectively preventing the liquid fuel from oxidizing and sintering due to high temperature, and then blocking the nozzle; after the switch, a clean external gas source and compressor exhaust gas or nitrogen gas source will purge the gaseous fuel pipeline, and safely discharge the gaseous fuel from the discharge valve to ensure a safe environment.

[0023] 3) When the fuel system of the present utility model switches from liquid fuel to gaseous fuel, after the switch, a clean external gas source and the gas of the compressor exhaust gas will backflush the liquid fuel pipeline, blowing the residual liquid fuel in the liquid fuel pipeline back into the container, effectively recovering the liquid fuel that cannot be utilized in the pipeline, and improving the fuel utilization efficiency. Description of the Drawings

[0024] Figure 1 is the system block diagram of the present utility model;

[0025] Figure 2 is the system block diagram of the present utility model based on a nitrogen gas source.

[0026] Wherein: 1. Gaseous fuel supply unit; 10. Manual switch valve; 11. Gaseous fuel filter; 12. Gaseous fuel flowmeter; 13. Fuel premixing valve; 14. Exhaust control valve; 15. Gaseous fuel stop valve; 16. Temperature sensor; 17. Pressure sensor a; 18. Main fuel flow control valve; 19. Bypass fuel control valve;

[0027] 2. External gas source supply unit; 20. External gas source filter; 21. Three-way valve a; 22. Three-way valve b;

[0028] 3. Liquid fuel supply unit; 30. Pressure sensor b; 31. Gear pump; 32. Liquid fuel filter; 33. Liquid fuel shut-off valve; 34. Liquid fuel three-way valve; 351. Liquid fuel flowmeter; 361. Liquid fuel check valve b; 37. Diverting valve; 352. Auxiliary oil circuit flowmeter; 363. Main oil circuit check valve; 362. Auxiliary oil circuit check valve; 38. Pressure sensor c;

[0029] 4. External water source supply unit; 401. External water source check valve a; 402. External water source check valve b;

[0030] 5. Compressor exhaust gas introduction unit; 50. Heat exchanger; 511. Backflush control valve a; 512. Backflush control valve b;

[0031] 6. Combustion chamber unit; 7. Nitrogen gas source. Detailed implementation manners

[0032] The following combines with the attached drawings to illustrate the detailed implementation manners of the present utility model.

[0033] The present utility model provides a gas turbine dual-fuel switching and purging cooling system, aiming to solve the problems of low fuel utilization rate in dual-fuel switching of existing gas turbines and unstable fuel before and after switching.

[0034] The present utility model includes a combustion chamber unit 6, which is used to convert the chemical energy in the fuel into heat energy to drive the turbine to do work, and has connecting pipes on both sides thereof to connect fuels of different media;

[0035] A gas fuel supply unit 1, one end of which is connected to the outside as an inlet and the other end of which is connected to one connecting pipe end of the combustion chamber unit 6 as an outlet, is used to supply gas fuel to the combustion chamber;

[0036] A liquid fuel supply unit 3, one end of which is connected to the outside as an inlet and the other end of which is connected to the other connecting pipe end of the combustion chamber unit 6 as an outlet, is used to supply liquid fuel to the combustion chamber;

[0037] An external gas source supply unit 2, which is connected in parallel to the gas fuel supply unit 1 and the liquid fuel supply unit 3. One side branch of the external gas source supply unit 2 is connected to the middle and rear sections of the gas fuel supply unit 1 to increase the intervention of the gas source to achieve fuel premixing and backflushing and discharging of the gas fuel. The other side branch of the external gas source supply unit 2 is connected to the middle and rear ends of the liquid fuel supply unit 3 to increase the intervention of the gas source to achieve atomization of the liquid fuel and backflushing of the liquid fuel;

[0038] An external water source supply unit 4, which is connected to the liquid fuel connecting pipe in front of the combustion chamber, is used to cool down the pipeline before switching from gas fuel to liquid fuel;

[0039] A compressor exhaust gas introduction unit 5, which is connected to a liquid fuel connection pipe to backflush the liquid fuel pipeline after the liquid fuel is switched to gas fuel.

[0040] In an embodiment of the present utility model, the gas fuel supply unit 1 sequentially includes a manual switch valve 10, a gas fuel filter 11, a gas fuel flowmeter 12, a fuel premixing valve 13, an exhaust control valve 14, a gas fuel stop valve 15, a temperature sensor 16, a pressure sensor a 17, a main fuel flow control valve 18, and a bypass fuel control valve 19. When the gas turbine is ignited, the main fuel flow control valve and the bypass fuel valve are opened. After the fuel is ignited, the bypass fuel valve is closed, and the main fuel flow control valve supplies the fuel. When there is too much gas fuel, the exhaust control valve 14 discharges the excess gas fuel.

[0041] In an embodiment of the present utility model, the liquid fuel supply unit 3 sequentially includes a pressure sensor b 30, a gear pump 31, a liquid fuel filter 32, a liquid fuel stop valve 33, a liquid fuel flowmeter 351, a liquid fuel check valve 361, a flow dividing valve 37, an auxiliary oil circuit flowmeter 352, a main oil circuit check valve 363, an auxiliary oil circuit check valve 362, and a pressure sensor c 38. The liquid fuel is configured to enter the liquid fuel pipeline through the gear pump 31, be filtered by the liquid fuel filter 32 and pass through the liquid fuel stop valve 33, then be mixed and atomized with the gas supplied by the external gas source unit, and then enter the flow dividing valve 37 through the flowmeter and the check valve for flow division. The flow dividing valve 37 is adjusted by the parameters of the two flowmeters, and finally enters the combustion chamber for combustion.

[0042] In an embodiment of the present utility model, the external gas source supply unit 2 sequentially includes an external gas source switch, an external gas source filter 20, a three-way valve a 21, and a three-way valve b 22.

[0043] In an embodiment of the present utility model, the external water source supply unit 4 includes an external water source, an external water source check valve a 401, and an external water source check valve b 402. The two check valves are connected before the gas fuel is switched to liquid fuel.

[0044] In an embodiment of the present utility model, the compressor exhaust gas introduction unit 5 includes a heat exchanger 50, a backflush control valve a 511, and a backflush control valve b 512 provided on the liquid fuel pipeline.

[0045] In an embodiment of the present utility model, the gas source of the compressor exhaust gas is an inert gas.

[0046] The specific structure and working principle of the present utility model:

[0047] Such as Figure 1As shown in the figure, the utility model mainly includes a gas fuel supply unit 1, an external gas source supply unit 2, a liquid fuel supply unit 3, an external water source supply unit 4, a compressor exhaust gas introduction unit 5, and a combustion chamber unit 6.

[0048] The preferred embodiment of the gas fuel supply unit 1 is as follows: it includes a manual switch valve 10, a gas fuel filter 11, a gas fuel flowmeter 12, a fuel premixing valve 13, an exhaust control valve 14, a gas fuel stop valve 15, a temperature sensor 16, a pressure sensor a 17, a main fuel flow control valve 18, and a bypass fuel control valve 19; its working principle is as shown in the figure, and the working process is as follows: First, the gas fuel enters the pipeline through the manual switch valve 10, is filtered by the gas fuel filter 11 and metered by the gas fuel flowmeter 12, and then is pre-mixed with the filtered external gas source, and then sent to the main fuel flow control valve. When the gas turbine is ignited, the main fuel flow control valve and the bypass fuel valve are opened. After the fuel is ignited, the bypass fuel valve is closed, and the main fuel flow control valve supplies the fuel; at the same time, when there is too much gas fuel, the excess gas fuel can also be safely discharged through the exhaust control valve 14.

[0049] The preferred embodiment of the external gas source supply unit 2 is as follows: it includes an external gas source switch, an external gas source filter 20, a three-way valve a 21, and a three-way valve b 22. The schematic diagram is as Figure 1 shown. The working process is as follows: After the external gas is filtered, a part of it enters the pipeline of the gas fuel to be pre-mixed with the fuel; a part enters the liquid fuel pipeline to atomize the liquid fuel to prevent blockage of the pipeline and nozzle; a part enters the rear side of the gas fuel discharge valve for backwashing to ensure the complete discharge of the gas fuel; finally, a part of the gas enters the backwashing pipeline of the liquid fuel to blow the liquid fuel back into the container.

[0050] The preferred embodiment of the liquid fuel supply unit 3 is as follows: it includes a pressure sensor b 30, a motor-driven gear pump 31, a liquid fuel filter 32, a liquid fuel stop valve 33, a liquid fuel flowmeter 351, a liquid fuel check valve 361, a flow dividing valve 37, an auxiliary oil circuit flowmeter 352, a main oil circuit check valve 363, an auxiliary oil circuit check valve 362, and a pressure sensor c 38. The principle is as Figure 1 shown. The working process is as follows: First, the liquid fuel enters the liquid fuel pipeline through the gear pump 31, is filtered by the liquid fuel filter 32 and passes through the liquid fuel stop valve 33, and then is mixed and atomized with the gas from the external gas source. Subsequently, it passes through the liquid fuel flowmeter 351 and the liquid fuel check valve 361 and enters the flow dividing valve 37 for flow division, and the flow dividing valve 37 can be adjusted through the parameters of the two flowmeters, and finally enters the combustion chamber for combustion.

[0051] A preferred embodiment of the external water source supply unit 4 is as follows: it includes an external water source, an external water source check valve a401, and an external water source check valve b402; the principle is as Figure 1 shown. Its working process is as follows: First, before switching the gaseous fuel to the liquid fuel, the external water source is introduced and flows into the liquid fuel pipe before the combustion chamber through the external water source check valve to cool down the pipe, thereby preventing the oxidation and consolidation of the liquid fuel.

[0052] A preferred embodiment of the compressor exhaust gas introduction unit 5 is as follows: it includes a heat exchanger 50, a backflush control valve a511, and a backflush control valve b512, and the principle is as Figure 1 shown. Its working process is as follows: First, the gas discharged from the compressor is cooled by the heat exchanger 50 and then enters the liquid fuel pipe. After switching the liquid fuel to the gaseous fuel, the liquid fuel pipe is purged to blow the residual liquid fuel in the pipe back into the container, thereby improving the fuel utilization efficiency; in addition, the gas fuel manifold can also be backflushed and then discharged from the gas fuel discharge valve. As a preferred solution, to ensure the safety of the gas fuel pipe, the backflush gas is replaced with an inert gas such as a nitrogen gas source 7, and the system block diagram of the nitrogen gas source 7 is as Figure 2 shown.

[0053] The specific working principle of the present utility model:

[0054] The present utility model adopts a combined supply of gaseous fuel and liquid fuel. When one kind of fuel is not sufficient to supply the demand, the system will switch to supply with the other kind of fuel. And whether it is liquid fuel supply or gaseous fuel supply, the pipe can be backflushed or cooled by an external gas source or an external water source, thereby improving the fuel utilization efficiency.

[0055] Specifically, when the gas turbine switches from gaseous fuel to liquid fuel, before the switch, relevant parameters are transmitted by the pressure sensor a17 to determine the need to switch fuels, and the external water source is introduced in advance. The cooling water enters the main liquid fuel pipe and the auxiliary liquid fuel pipe through the external water source check valve a401 and the external water source check valve b402 to cool the pipe. After cooling, the liquid fuel is introduced. The liquid fuel is divided into the combustion chamber after passing through the gear pump 31, the liquid fuel filter 32, the liquid fuel stop valve 33, atomization, the liquid fuel flowmeter 351, and the liquid fuel check valve 361. As the liquid fuel enters, the stop valve of the gaseous fuel is closed, and at the same time, an external gas source and the compressor exhaust gas are introduced to backflush the gas pipe, so that the gaseous fuel in the pipe is safely discharged through the discharge valve.

[0056] When the gas turbine is switched from liquid fuel to gas fuel, before the switch, relevant parameters are transmitted by pressure sensor b30 and pressure sensor c38 to determine the need to switch fuels. The liquid fuel stop valve 33 on the liquid fuel pipeline is closed, and gas fuel is introduced. Subsequently, the external gas source is filtered clean by the external gas source filter 20 and then passes through the three-way valve a21, the three-way valve b22, and the liquid fuel three-way valve 34 to purge the residual liquid fuel in the pipeline. At the same time, the gas discharged from the compressor passes through the heat exchanger 50 and then backwashes the pipelines of the main liquid fuel and the auxiliary liquid fuel. After passing through the backwash control valve a511 and the backwash control valve b512, the purged liquid fuel is sent back to the container.

[0057] The above description is an explanation of the present invention, not a limitation of the invention. The scope defined by the present invention can be seen in the claims. Any form of modification can be made within the protection scope of the present invention.

Claims

1. A gas turbine dual-fuel switching and purging cooling system, characterized in that, Comprising: A combustion chamber unit (6) for converting the chemical energy in the fuel into heat energy to drive the turbine to do work, and having connecting pipes on both sides thereof to connect fuels of different media; A gaseous fuel supply unit (1), one end of which is connected to the outside as an inlet and the other end of which is connected to a connecting pipe at one end of the combustion chamber unit (6) as an outlet, for supplying gaseous fuel to the combustion chamber; A liquid fuel supply unit (3), one end of which is connected to the outside as an inlet and the other end of which is connected to a connecting pipe at the other end of the combustion chamber unit (6) as an outlet, for supplying liquid fuel to the combustion chamber; An external gas source supply unit (2) which is connected in parallel to the gaseous fuel supply unit (1) and the liquid fuel supply unit (3). One side branch of the external gas source supply unit (2) is connected to the middle section and the rear section of the gaseous fuel supply unit (1) to increase the intervention of the gas source to achieve pre-mixing of the fuel and the back-blowing and discharging of the gaseous fuel. The other side branch of the external gas source supply unit (2) is connected to the middle section and the rear end of the liquid fuel supply unit (3) to increase the intervention of the gas source to achieve atomization of the liquid fuel and the back-blowing of the liquid fuel; An external water source supply unit (4) which is connected to the liquid fuel connecting pipe in front of the combustion chamber for cooling and temperature reduction of the pipeline before the gaseous fuel is switched to liquid fuel; A compressor exhaust gas introduction unit (5) which is connected to the liquid fuel connecting pipe to back-blow the liquid fuel pipeline after the liquid fuel is switched to gaseous fuel; 2. The dual-fuel switching and purging cooling system for a gas turbine according to claim 1, wherein: The gaseous fuel supply unit (1) sequentially includes a manual switch valve (10), a gaseous fuel filter (11), a gaseous fuel flowmeter (12), a fuel pre-mixing valve (13), an exhaust control valve (14), a gaseous fuel stop valve (15), a temperature sensor (16), a pressure sensor, a main fuel flow control valve (18), and a bypass fuel control valve (19). When the gas turbine is ignited, the main fuel flow control valve (18) and the bypass fuel control valve (19) are opened. After the fuel is ignited, the bypass fuel control valve (19) is closed, and the main fuel flow control valve (18) supplies the fuel. When there is too much gaseous fuel, the exhaust control valve (14) discharges the excess gaseous fuel; 3. A gas turbine dual-fuel switching and purging cooling system according to claim 1, characterized in that: The liquid fuel supply unit (3) sequentially includes two pressure sensors at the front and rear, a gear pump (31), a liquid fuel filter (32), a liquid fuel stop valve (33), a liquid fuel flowmeter (351), a liquid fuel check valve (361), a diverter valve (37), an auxiliary oil circuit flowmeter (352), a main oil circuit check valve (363), and an auxiliary oil circuit check valve (362). The liquid fuel is configured to enter the liquid fuel pipeline through the gear pump (31), be filtered by the liquid fuel filter (32) and pass through the liquid fuel stop valve (33), then be mixed and atomized with the gas supplied by the external gas source unit, and then enter the diverter valve (37) for diversion through the flowmeter and the check valve. The diverter valve (37) is adjusted by the parameters of the two flowmeters and finally enters the combustion chamber for combustion; 4. A gas turbine dual-fuel switching and purging cooling system according to claim 1, characterized in that: The external gas source supply unit (2) sequentially includes an external gas source switch, an external gas source filter (20), and two three-way valves.

5. A gas turbine dual-fuel switching and purging cooling system according to claim 1, characterized in that: The external water source supply unit (4) includes an external water source and an external water source one-way valve, and the external water source one-way valve is connected before the gas fuel is switched to liquid fuel.

6. A gas turbine dual-fuel switching and purging cooling system according to claim 1, characterized in that: The compressor exhaust gas introduction unit (5) includes a heat exchanger (50) provided on the liquid fuel pipeline and two groups of backflush control valves.

7. The dual-fuel switching and purging cooling system of a gas turbine according to claim 6, characterized in that: The gas source of the compressor exhaust gas is an inert gas.

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