Fuel premixing device of gas turbine

Abstract

The utility model relates to a fuel premixing device of a gas turbine, which is characterized in that an electric valve and a basket filter are sequentially connected on a fuel gas adjusting inlet pipeline, the input end of the electric valve is connected with natural gas, the output end of the basket filter is respectively connected with an ignition pipeline and a combustor pipeline, and the other end of the ignition pipeline is connected with the input end I of a mixer; the second input end of the mixer is connected with a gas compressor of the gas turbine, the output end of the mixer is connected into a gas ignition burner, and the other end of the burner pipeline is connected into a burner of the gas turbine. The three-way regulating valve has the advantages that the three-way regulating valve is convenient for ensuring that the flow distribution average and accuracy of the three-way regulating burner main path 2a and the three-way regulating burner main path 2b are improved by adopting the three-way regulating valve under a rated working condition, and the distribution accuracy of the three-way regulating burner main path 2b and the on-duty burner loop is improved by adopting the three-way regulating valve; and the safety of a combustor pipeline is ensured by adopting a redundant quick cut-off valve. And the basket type filter is adopted, so that the cleanliness of inlet air is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of gas turbines, in particular to a premixed fuel device for a gas turbine. Background Technique

[0002] The core problem of the dry low-emission combustion technology of gas turbines is to solve the stability of premixed combustion. For combustion control, diffusion combustion is the most stable state, but it is usually accompanied by high nitrogen oxide emissions. Premixed combustion can significantly reduce harmful gas emissions. However, the stability of premixed combustion itself is extremely poor, and it is impossible to ensure the continuity of combustion during the variable load operation and start-stop operation stages of gas turbines, resulting in a high probability of the gas turbine stalling and shutting down. Therefore, for a low-emission combustion chamber, it is necessary to solve the stability of the gas turbine under variable operating conditions.

[0003] The dry low-emission combustion chamber splits the fuel nozzle into two or more different channels, where at least one channel is a pure fuel channel and the remaining channels are fuel / air mixture channels. During the start-up stage and low-load stage of the gas turbine, the control valves in the fuel system can control most or all of the fuel to enter the pure fuel channel. When the power of the gas turbine reaches a certain load, the fuel in the mixing channel is gradually increased, and at the same time, the fuel in the pure fuel channel is synchronously reduced until all the fuel enters the combustion chamber through the mixing channel. At present, the distribution of fuel in different fuel channels completely depends on electric valves, and the existing problems are as follows:

[0004] 1. It is extremely difficult to ensure the control accuracy of the valve under low opening degrees;

[0005] 2. When load shedding occurs, the risk of stalling and shutting down is relatively high, and stalling and shutting down have a very bad impact on the service life of the gas turbine. Content of the Utility Model

[0006] The purpose of the utility model is to provide a premixed fuel device for a gas turbine, which reduces the risk of the gas turbine stalling and shutting down and improves the stability of the gas turbine in low-emission combustion.

[0007] To achieve the above purpose, the utility model is realized through the following technical solutions:

[0008] A premixed fuel system for a gas turbine includes a gas regulating inlet pipeline, a burner pipeline, and an ignition pipeline. An electric valve and a basket filter are sequentially connected to the gas regulating inlet pipeline. The input end of the electric valve is connected to natural gas, and the output end of the basket filter is respectively connected to the ignition pipeline and the burner pipeline. The other end of the ignition pipeline is connected to one input end of a mixer, the second input end of the mixer is connected to the gas compressor of the gas turbine, the output end of the mixer is connected to a gas ignition burner, and the other end of the burner pipeline is connected to the gas turbine burner.

[0009] The burner pipeline is successively connected with a first quick cut-off valve, a second quick cut-off valve, a first regulating valve, a first three-way regulating valve, and a second three-way regulating valve. The third port of the first three-way regulating valve is connected to the first main burner path, the third port of the second three-way regulating valve is connected to the standby burner loop, and the second port of the second three-way regulating valve is connected to the second main burner path.

[0010] The ignition pipeline is successively connected with a solenoid valve, a stop valve, and a second regulating valve. A stop valve is connected between the solenoid valve and the stop valve, and the input end of the stop valve is connected to the vent pipeline.

[0011] A flow meter is connected between the second quick cut-off valve and the first regulating valve.

[0012] It further includes a bypass pipeline. One end of the bypass pipeline is respectively communicated with the second quick cut-off valve and the first regulating valve, the other end of the bypass pipeline is communicated with the first three-way regulating valve, and an orifice plate is connected to the bypass pipeline.

[0013] The output end of the first quick cut-off valve is connected to the vent pipeline, the output end of the first regulating valve is connected to the vent pipeline, and the input end of the first quick cut-off valve is communicated with the output end of the first regulating valve.

[0014] The first main burner path, the second main burner path, and the standby burner loop are all connected to the burner in the combustion chamber.

[0015] The number of burners is several. Each burner is provided with a first fuel hole, a second fuel hole, and a third fuel hole. The first main burner path is connected to the first fuel hole, the second main burner path is connected to the second fuel hole, the standby burner loop is connected to the third fuel hole, and the numbers of the first fuel hole, the second fuel hole, and the third fuel hole are all several.

[0016] Compared with the prior art, the beneficial effects of the present utility model are:

[0017] 1. A basket filter GLD is connected to the gas regulating inlet pipeline to ensure the cleanliness of the inlet gas and filter out impurities such as particulate matter contained in the gas;

[0018] 2. The use of a three-way regulating valve 90GS1 improves the flow distribution evenness and accuracy of the first main burner path of the three-way regulating burner and the second main burner path of the three-way regulating burner. The use of a three-way regulating valve 90GS2 improves the accuracy of the distribution between the second main burner path of the three-way regulating burner and the standby burner loop;

[0019] 3. The first quick cut-off valve GSOV25 and the second quick cut-off valve GSOV25 of the burner pipeline are used to double-redundantly cut off the fuel of the main path to ensure the safety of the burner pipeline;

[0020] 4. The output end of the quick cut-off valve GSOV25 is connected to the vent pipeline, and the output end of the regulating valve GS16 is connected to the vent pipeline, so that after the shutdown, the residual natural gas in the discharge pipeline can be discharged to improve safety.

[0021] 5. In the bypass pipeline, a replaceable orifice plate 96GFDA is provided, which is used to determine the natural gas flow rate through the bypass during the commissioning process. The structure is simple and the operation is convenient.

[0022] 6. In the ignition pipeline, a switch valve 20GFI1 and a stop valve 20GFI2 are set to ensure that natural gas enters the mixer in the ignition pipeline, increasing the ignition success rate.

[0023] 7. The small amount of diffusion combustion in the duty burner circuit can ensure a relatively stable ignition source point in the main combustion zone of the combustion chamber, ensuring the continuous and stable combustion. Brief Description of the Drawings

[0024] Figure 1 It is a schematic structural diagram of a gas turbine premixed fuel system. Detailed Embodiment

[0025] The present invention will be described in detail below with reference to the accompanying drawings of the specification, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0026] The following embodiments are implemented on the premise of the technical solution of the present invention, and the detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments. The methods used in the following embodiments are all conventional methods unless otherwise specified.

[0027]

Embodiment 1

[0028] See Figure 1 , a gas turbine premixed fuel device, including a gas regulation inlet pipeline, a burner pipeline, an ignition pipeline, and a bypass pipeline. An electric valve 20GSD and a basket filter GLD are sequentially connected to the gas regulation inlet pipeline. The input end of the electric valve 20GSD is connected to natural gas, and the output end of the basket filter GLD is respectively connected to the ignition pipeline and the burner pipeline. The other end of the ignition pipeline is connected to the first input end of the mixer, the second input end of the mixer is connected to the gas turbine compressor, and the output end of the mixer is connected to the gas ignition burner. The other end of the burner pipeline is connected to the gas turbine burner.

[0029] The burner pipeline is successively connected with a quick cut-off valve 1 GSOV25, a quick cut-off valve 2 GSOV25, a regulating valve 1 GS16, a three-way regulating valve 90GS1, and a three-way regulating valve 90GS2. The third port of the three-way regulating valve 90GS1 is connected to the main burner path 2a, and the third port of the three-way regulating valve 90GS2 is connected to the duty burner loop. The second port of the three-way regulating valve 90GS2 is connected to the main burner path 2b. The fuel system is connected to the combustion chamber (from the outlet section of the fuel system to the burner, and the burner is also called the fuel nozzle. There are six fuel nozzles in each combustion chamber, and the six fuel nozzles are connected in parallel. Each fuel nozzle has seven fuel holes. Among them, three fuel holes of each fuel nozzle are connected to the main burner path 2a, and the other three fuel holes of each fuel nozzle are connected to the main burner path 2b. The last fuel hole of each fuel nozzle is connected to the duty burner loop. The existence of the duty burner loop ensures that there is a certain amount of pure natural gas diffusion combustion in the combustion chamber at any operating stage. That is, through the three-way regulating valve 90GS1 and the three-way regulating valve 90GS2, all the natural gas enters the main burner path 2a and the main burner path 2b. The three-way regulating valve 90GS1 is in an evenly distributed state. When the three-way regulating valve 90GS2 completely closes the duty burner loop, there is still pure natural gas entering the duty burner loop through the bypass. The main burner path 2a and the main burner path 2b are both premixed combustion, and their stability is poor. There is a high risk of flameout under conditions such as the gas turbine shedding load and reducing power. The small amount of diffusion combustion in the duty burner loop can ensure a relatively stable ignition source point in the main combustion zone of the combustion chamber, ensuring the continuous and stable combustion.

[0030] A flow meter 96GFD3 is connected between the quick cut-off valve 2 GSOV25 and the regulating valve 1 GS16; one end of the bypass pipeline is respectively communicated with the quick cut-off valve 2 GSOV25 and the regulating valve 1 GS16, and the other end of the bypass pipeline is communicated with the three-way regulating valve 90GS1. A throttle orifice plate 96GFDA is connected to the bypass pipeline.

[0031] The ignition pipeline is successively connected with a switch solenoid valve 20GFI1, a stop valve 20GFI2, and a regulating valve 2 96GFD0; a stop valve 20VG2 is connected between the stop valves 20GFI2, and the input end of the stop valve 20VG2 is connected to the vent pipeline.

[0032] Working process:

[0033] Natural gas enters from the inlet, passes through the electric valve 20GSD, and divides into two paths in front of the quick cut-off valve one GSOV25. One path leads to the ignition pipeline, and the other path continues to flow towards the main burner. Two quick cut-off valves are installed in the main circuit: the quick cut-off valve one GSOV25 and the quick cut-off valve two GSOV25 are sequentially arranged in the burner pipeline to ensure dual-redundancy cut-off to ensure safety. After passing through the flowmeter 96GFD3, it divides into two paths. The main path enters the regulating valve one GS16, and the bypass pipeline bypasses all the subsequent valves through a DN20 pipeline and directly accesses the duty circuit. A replaceable orifice plate 96GFDA is installed in the bypass pipeline to facilitate adjusting and determining the natural gas flow through the duty bypass during the commissioning process. After the natural gas in the main path passes through the regulating valve one GS16, it divides into two paths at the input end of the three-way regulating valve 90GS1. One path leads to the main path 2a of the three-way regulating burner, and the other path leads to the regulating valve two 90GS2. It further divides into two paths at the output end of the three-way regulating valve 90GS2, leading to the main path 2b of the three-way regulating burner and the duty burner circuit respectively. There is natural gas passing through the main circuit three-way regulating valve 90GS1 and continuously flowing into the duty burner circuit in the duty burner circuit; The working mode specifically includes the following contents: 1) The cut-off valve 20GFI2 in the ignition pipeline works in an intermittent start mode, and the maintained switching time ratio is adjustable between 1:1 and 6:1; 2) The proportion of the natural gas volume passing through the bypass in the orifice plate 96GFDA does not exceed 8% of the total natural gas flow, so that the combustion emissions do not exceed the standard; It should be ensured that the proportion of the natural gas volume passing through the bypass in the orifice plate 96GFDA is not less than 4% of the total flow, so that the stable combustion of the ignition source point in the duty burner circuit can be achieved; 3) When the gas turbine enters the ignition condition: the electric valve 20GSD is opened, the quick cut-off valve one GSOV25 and the quick cut-off valve two GSOV25 are closed, the switching solenoid valve 20GFI1 and the cut-off valve 20GFI2 are opened, and the ignition circuit is ignited; The three-way regulating valve 90GS1 is fully directed towards the three-way regulating valve 90GS2, the main path 2a of the three-way regulating burner is in the closed state, the three-way regulating valve 90GS2 is fully directed towards the duty burner circuit, and the main path 2b of the three-way regulating burner is fully closed; 4) After ignition is successful until the gas turbine is at full speed and no-load state, the content is as follows: a. The ignition circuit is closed: the three-way regulating valve 90GS1 and the three-way regulating valve 90GS2 are not adjusted, the switching solenoid valve 20GFI1 and the cut-off valve 20GFI2 are closed, and the quick cut-off valve one GSOV25 and the quick cut-off valve two GSOV25 are opened; b. Gradually increase the opening of the electric valve 20GSD to increase the natural gas volume; c. When the gas turbine increases the output power from full speed and no-load, when the output power of the gas turbine increases to 30% of the load, adjust the three-way regulating valve 90GS1 and the three-way regulating valve 90GS2 to distribute the natural gas fuel volume to the main path 2a of the three-way regulating burner and the main path 2b of the three-way regulating burner, and reduce the natural gas fuel volume passing through the duty burner circuit;When the output power of the gas turbine increases to 50% load, adjust the three-way regulating valve 90GS1 and the three-way regulating valve 90GS2 so that the natural gas fuel quantities distributed to the main burner paths 2a and 2b of the three-way regulating burner are the same, point the three-way regulating valve 90GS1 completely towards the three-way regulating valve 90GS2, and close the standby burner circuit to ensure that the gas turbine does not flame out; when the output power of the gas turbine increases to 75% load, confirm that the three-way regulating valve 90GS1 is completely pointed towards the three-way regulating valve 90GS2 and close the standby burner circuit; when continuously increasing the output power of the gas turbine, for the three-way regulating valve 90GS1, evenly distribute the fuel to the main burner paths 2a of the three-way regulating burner and the three-way regulating valve 90GS2, and adjust the fuel quantity of the gas turbine only by adjusting the opening degree of the electric valve 20GSD.;

[0034] A basket filter GLD is connected to the gas regulating intake pipeline of the present utility model to ensure the cleanliness of the intake air and filter out impurities such as particulate matter contained in the gas; the use of the three-way regulating valve 90GS1 improves the flow distribution evenness and accuracy between the main burner paths 2a and 2b of the three-way regulating burner, and the use of the three-way regulating valve 90GS2 improves the distribution accuracy between the main burner path 2b of the three-way regulating burner and the standby burner circuit; the quick cut-off valve I GSOV25 and the quick cut-off valve II GSOV25 on the burner pipeline are used for double-redundancy cut-off of the fuel in the main path to ensure the safety of the burner pipeline; the output end of the quick cut-off valve I GSOV25 is connected to the vent pipeline, and the output end of the regulating valve I GS16 is connected to the vent pipeline, so that after shutdown, the residual natural gas in the pipeline is discharged to improve safety; in the bypass pipeline, a replaceable orifice plate 96GFDA is provided, which is used to determine the natural gas flow rate through the bypass during the commissioning process, with a simple structure and convenient operation; in the ignition pipeline, a switch valve 20GFI1 and a stop valve 20GFI2 are provided to ensure that natural gas enters the mixer in the ignition pipeline and increase the ignition success rate; the small amount of diffusion combustion in the standby burner circuit can ensure a relatively stable ignition source point in the main combustion zone of the combustion chamber and ensure the continuous and stable combustion.

Claims

1. A gas turbine premix fuel device, characterized in that: It includes a gas regulating air intake pipeline, a burner pipeline, and an ignition pipeline. The gas regulating air intake pipeline is connected with an electric valve and a basket filter in sequence. The input end of the electric valve is connected to natural gas, and the output end of the basket filter is connected to the ignition pipeline and the burner pipeline respectively. The other end of the ignition pipeline is connected to the input end 1 of the mixer, and the input end 2 of the mixer is connected to the gas turbine compressor. The output end of the mixer is connected to the gas ignition burner, and the other end of the burner pipeline is connected to the gas turbine burner.

2. A gas turbine premix fuel device according to claim 1, characterized in that: The burner pipeline is connected with quick shut-off valve 1, quick shut-off valve 2, regulating valve 1, three-way regulating valve 1, and three-way regulating valve 2 in sequence. The third port of three-way regulating valve 1 is connected to burner main line 1, the third port of three-way regulating valve 2 is connected to the duty burner circuit, and the second port of three-way regulating valve 2 is connected to burner main line 2.

3. A gas turbine premix fuel device according to claim 1, characterized in that: The ignition pipeline is connected with a switch solenoid valve, a stop valve and a second regulating valve in sequence, a stop valve is connected between the switch solenoid valve and the stop valve, and an input end of the stop valve is connected to a vent pipeline.

4. A gas turbine premix fuel device according to claim 2, characterized in that: A flow meter is connected between the second quick-cut valve and the first regulating valve.

5. A gas turbine premix fuel device according to claim 2, characterized in that: It also includes a bypass pipeline, one end of which is connected to the second quick-cut valve and the first regulating valve respectively, and the other end of the bypass pipeline is connected to the first three-way regulating valve. A throttling orifice plate is connected to the bypass pipeline.

6. A gas turbine premix fuel device according to claim 2, characterized in that: The output end of the quick cut-off valve 1 is connected to the venting pipeline, the output end of the regulating valve 1 is connected to the venting pipeline, and the input end of the quick cut-off valve 1 is connected to the output end of the regulating valve 1.

7. A gas turbine premix fuel device according to claim 2, characterized in that: Burner main circuit 1, burner main circuit 2 and duty burner circuit are all connected to the burner in the combustion chamber.

8. A gas turbine premix fuel device according to claim 7, characterized in that: The number of burners is several, and each burner is provided with fuel hole one, fuel hole two, and fuel hole three. The main line one of the burner is connected with the combustion hole one, the main line two of the burner is connected with the combustion hole two, and the duty burner circuit is connected with the combustion hole three. The number of fuel hole one, fuel hole two, and fuel hole three are all several.

Images