Low carbon emission pipeline driven compressor unit control system and control method

Abstract

The present application relates to the technical field of gas turbine, and discloses a low-carbon emission pipeline combustion-driven compressor unit control system, which comprises a main fuel supply pipe, further comprises a low-carbon fuel pipe, the main fuel supply pipe is sequentially provided with a natural gas front stop valve, a natural gas separator, a natural gas rear stop valve and a natural gas regulating valve in the direction from the air inlet to the air outlet, the air inlet of the low-carbon fuel pipe is connected with the main fuel supply pipe at the inlet end of the natural gas front stop valve, the air outlet of the low-carbon fuel pipe is connected with the main fuel supply pipe at the outlet end of the natural gas regulating valve, the low-carbon fuel pipe is sequentially provided with a first low-carbon fuel stop valve, a second low-carbon fuel stop valve and a low-carbon fuel regulating valve in the direction from the air inlet to the air outlet; and a control method of the low-carbon emission pipeline combustion-driven compressor unit is also disclosed; the present application can stabilize the starting of the pipeline combustion-driven compressor unit, and can also stabilize the switching of the low-carbon fuel supply, thereby effectively improving the use effect of the pipeline combustion-driven compressor unit and reducing the risk of abnormal shutdown.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, and in particular to a control system and control method for a low-carbon emission pipeline gas-driven compressor unit. Background Technology

[0002] Implementing low-carbon emission reduction has become a global consensus. To achieve the ultimate goal of zero carbon emissions, my country will inevitably undergo a transition from traditional fossil fuels, primarily coal, to renewable energy. Ensuring a stable, orderly, safe, and controllable energy supply during this transition period, and guaranteeing the stable transportation of low-carbon fuels, such as hydrogen, across the country, is crucial. Based on existing oil and gas pipelines, developing natural gas blended with hydrogen transportation is the most economically feasible clean energy transportation approach. Natural gas blending technology involves adding hydrogen to natural gas at a specific volume ratio to create hydrogen-blended natural gas, which can be transported through existing natural gas pipelines and directly replace natural gas. By blending in an appropriate proportion of hydrogen, carbon emissions can be effectively reduced. Gas turbines, due to their high power density, high efficiency, and fast start-up speed, are currently the main power drive equipment for pressurizing natural gas transportation and are widely used in my country's natural gas pressurization and transportation industry. Gas turbines can directly use the pressurized natural gas as fuel, making gas turbine-driven natural gas compressor units independent of electricity supply and suitable for various harsh production environments.

[0003] When hydrogen and natural gas are blended for transportation, the gas turbine-driven natural gas compressor unit, also known as the combustion-driven compressor unit, needs to use a blended hydrogen and natural gas fuel as a new fuel. Furthermore, using hydrogen-containing fuel itself can achieve carbon emission reduction in the gas pressurization and transportation process. However, due to significant differences in the physical properties of hydrogen compared to natural gas, hydrogen is characterized by difficulties in controlling its combustion flame temperature, and is prone to backfire, self-ignition, and thermoacoustic instability. Therefore, the operating characteristics of gas turbines using high-hydrogen-content or pure hydrogen fuel differ considerably from those using traditional natural gas fuel. This led to Chinese invention patent application number 202211097541.1, which discloses a control method and device for a pure hydrogen gas turbine system to address the problem of unstable combustion flames in pure hydrogen gas turbines.

[0004] The existing technology has at least the following problems:

[0005] First, the high hydrogen content of the fuel makes it easy to diffuse, requires less energy to ignite, and has a fast flame propagation speed. Directly using hydrogen-rich low-carbon fuel as the ignition and starting fuel for gas turbines would be difficult to control, and new starting methods are needed to achieve safe starting of gas turbines.

[0006] Secondly, the combustion of hydrogen-rich low-carbon fuels is unstable. During the adjustment of operating conditions, local overheating or flameout may occur. Reasonable control technology is needed to ensure that when using hydrogen-rich low-carbon fuels, the risk of abnormal shutdown of natural gas pipeline combustion-driven compressor units does not increase compared with the use of traditional natural gas fuels. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention develops a low-carbon emission pipeline fuel-driven compressor unit control system and control method. This invention can stably start the pipeline fuel-driven compressor unit and stably switch the supply of low-carbon fuel, effectively improving the performance of the pipeline fuel-driven compressor unit and reducing the risk of abnormal shutdown.

[0008] The technical solution to the technical problem solved by the present invention is as follows: On the one hand, the present invention provides a low-carbon emission pipeline combustion-driven compressor unit control system, including a main fuel supply pipe and a low-carbon fuel pipe. The main fuel supply pipe is provided with a natural gas pre-stop valve, a natural gas separator, a natural gas post-stop valve and a natural gas regulating valve in sequence from the inlet to the outlet. The inlet of the low-carbon fuel pipe is connected to the main fuel supply pipe at the inlet end of the natural gas pre-stop valve, and the outlet of the low-carbon fuel pipe is connected to the main fuel supply pipe at the outlet end of the natural gas regulating valve. The low-carbon fuel pipe is provided with a first low-carbon fuel stop valve, a second low-carbon fuel stop valve and a low-carbon fuel regulating valve in sequence from the inlet to the outlet.

[0009] As an optimization, a first discharge pipe is provided on the main fuel supply pipe between the natural gas separator and the natural gas after-stop valve, and a second discharge pipe is provided on the main fuel supply pipe between the natural gas after-stop valve and the natural gas regulating valve. By setting the first and second discharge pipes, all residual combustible gases in the pipeline and the natural gas separator can be removed before switching fuels.

[0010] As an optimization, a first vent valve is provided on the first discharge pipe, and a second vent valve is provided on the second discharge pipe. By setting the first vent valve and the second vent valve, the on / off state of the first discharge pipe and the second discharge pipe can be controlled respectively.

[0011] As an optimization, a third discharge pipe is provided on the low-carbon fuel pipe between the first and second low-carbon fuel shut-off valves, and a fourth discharge pipe is provided on the low-carbon fuel pipe between the second low-carbon fuel shut-off valve and the low-carbon fuel regulating valve. By setting the third and fourth discharge pipes, the pipeline can be filled in conjunction with the first low-carbon fuel shut-off valve to prevent pipeline delays from causing fluctuations in operating conditions. After shutdown, the mixed fuel in the low-carbon fuel pipe can be vented.

[0012] As an optimization, a third vent valve is installed on the third discharge pipe, and a fourth vent valve is installed on the fourth discharge pipe. By installing the third and fourth vent valves, the on / off state of the third and fourth discharge pipes can be controlled separately.

[0013] As an optimization, the natural gas pre-stop valve, natural gas post-stop valve, first low-carbon fuel stop valve, second low-carbon fuel stop valve, first vent valve, second vent valve, third vent valve, and fourth vent valve are all solenoid valves, while the natural gas regulating valve and low-carbon fuel regulating valve are all electric valves. By setting solenoid valves with faster opening or closing speeds, the pipeline can be opened or closed quickly; by setting electric valves, the valve opening degree can be controlled.

[0014] As an optimization, the natural gas separator is equipped with a separation pipeline. By setting up the separation pipeline, the separated hydrogen gas can be discharged.

[0015] On the other hand, the present invention also provides a control method for a low-carbon emission pipeline combustion-driven compressor unit, comprising the following steps:

[0016] S1. Gas generator turning gear start control: By controlling the supply of high-pressure hydraulic oil, the output power of the hydraulic motor installed on the gas generator is controlled, and the hydraulic motor drives the gas generator to start to 20% to 30% of the rated speed.

[0017] S2. Gas generator turning gear purging control: Through proportional-integral regulation, the gas generator is controlled to operate stably at 20% to 30% of the rated speed for 1.5 to 2 times the air flow channel replacement time. At the same time as the gas generator is purging, the natural gas front shut-off valve and the natural gas separator are opened.

[0018] S3. Ignition control of gas generator: By first reducing and then increasing the supply of high-pressure hydraulic oil, the power of the hydraulic motor is first reduced and then increased, so that the speed of the gas generator is first reduced and then increased; during the speed increase process, the first vent valve and the second vent valve are closed, the natural gas shut-off valve is opened at the same time, and the natural gas regulating valve is controlled to give a fixed amount of natural gas fuel within the range of 15% to 25% of the rated speed of the gas generator.

[0019] S4. Speed-up control after gas generator ignition: Based on the fixed natural gas fuel quantity given in step S3, and according to the deviation between the current speed and the idle speed, the fuel increment is calculated using the proportional-integral formula to obtain the fuel quantity of the gas turbine. The opening of the natural gas regulating valve is controlled according to the change in fuel demand, and the opening of the natural gas regulating valve is gradually increased. During the speed-up process, the hydraulic motor is separated from the gas generator, and the speed-up of the gas generator is driven entirely by the heat generated by the combustion of natural gas fuel.

[0020] S5. Gas generator idle speed self-sustaining operation control: After accelerating to the gas generator idle speed, control the speed to the idle speed and warm up the machine. At the same time, open the first low-carbon fuel shut-off valve and the third vent valve to inject hydrogen and natural gas mixed fuel into the low-carbon fuel pipe to fill the pipeline and prevent pipeline delivery delays from causing fluctuations in operating conditions.

[0021] S6. Low-carbon fuel switching: After the warm-up is completed, start switching to low-carbon fuel. After closing the fourth vent valve, open the second low-carbon fuel shut-off valve. Then, control the low-carbon fuel regulating valve to start opening from the fully closed state, and at the same time control the natural gas regulating valve to start closing from the current opening state. Gradually close the natural gas regulating valve until it is completely closed, then close the natural gas front shut-off valve and the natural gas rear shut-off valve. Then, open the first vent valve and the second vent valve. At the same time, the natural gas separator stops working, and the fuel switching is completed.

[0022] S7. Power Turbine No-Load Speed ​​Increase: After completing the low-carbon fuel switch, the target speed of the power turbine is set to the no-load speed value, and the target speed of the gas generator is set to the safe speed limit value of 100% to 110% of the rated speed; the power turbine is accelerated to the no-load speed by the increased high-temperature and high-pressure gas flow from the gas generator.

[0023] S8. Compressor load regulation: After the power turbine reaches the no-load speed, set the target value of the coaxial speed of the power turbine and compressor required for the final gas compression and delivery production. The compressor speed is automatically increased through the same low-carbon fuel regulation method as the power turbine no-load speed increase, to reach the final production speed.

[0024] S9. Speed ​​Reduction Shutdown: When performing a normal shutdown while operating on low-carbon fuel, first reduce the operating speed from normal speed to the power turbine no-load condition; then reduce the power turbine no-load condition to the gas generator idle speed, and maintain operation for 5-10 minutes after reaching idle speed; finally, cut off the fuel supply directly at idle speed, close the first low-carbon fuel shut-off valve, the second low-carbon fuel shut-off valve, and the low-carbon fuel regulating valve, and open the third and fourth vent valves to automatically shut down the gas turbine. After supplying high-pressure hydraulic oil at 20%-30% turning speed for 10-15 minutes of turning, the speed is finally reduced to zero, completing the shutdown.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] By installing a main fuel supply pipe, fuel can be supplied to the gas turbine; by installing a low-carbon fuel pipe, blended fuel can be supplied to the gas turbine after fuel switching; by installing a natural gas pre-stop valve, the on / off state of the main fuel supply pipe can be controlled; by installing a natural gas separator, blended fuel can be separated, and pure natural gas can be supplied to the gas turbine through the main fuel supply pipe, enabling stable gas turbine start-up and reducing start-up difficulty; by installing a natural gas post-stop valve, in conjunction with the natural gas pre-stop valve, the on / off state of the main fuel supply pipe can be controlled; by installing a natural gas regulating valve, the opening degree can be adjusted during fuel switching to control and reduce the main fuel supply. The system supplies pure natural gas until it is completely shut off. A first low-carbon fuel shut-off valve controls the on / off flow of the low-carbon fuel pipeline. A second low-carbon fuel shut-off valve works in conjunction with the first to control the on / off flow of the low-carbon fuel pipeline. A low-carbon fuel regulating valve adjusts its opening during fuel switching to increase the supply of blended fuel in the low-carbon fuel pipeline, working in conjunction with the natural gas regulating valve to achieve stable fuel switching. This invention can stably start the pipeline fuel-driven compressor unit and stably switch the supply of low-carbon fuel, effectively improving the performance of the pipeline fuel-driven compressor unit and reducing the risk of abnormal shutdowns. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a low-carbon emission pipeline combustion-driven compressor unit control system according to the present invention.

[0028] Figure 2 This is a schematic flowchart of a low-carbon emission pipeline combustion-driven compressor unit control method according to the present invention.

[0029] In the diagram: 1. Main fuel supply pipe; 11. Natural gas front shut-off valve; 12. Natural gas separator; 13. Natural gas rear shut-off valve; 14. Natural gas regulating valve; 2. Low-carbon fuel pipe; 21. First low-carbon fuel shut-off valve; 22. Second low-carbon fuel shut-off valve; 23. Low-carbon fuel regulating valve; 3. Blended fuel supply pipe; 4. Gas turbine body fuel supply pipe; 5. First exhaust pipe; 51. First vent valve; 6. Second exhaust pipe; 61. Second vent valve; 7. Third exhaust pipe; 71. Third vent valve; 8. Fourth exhaust pipe; 81. Fourth vent valve. Detailed Implementation

[0030] To clearly illustrate the technical features of this solution, the invention will be described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0031] Example 1

[0032] Figure 1This is a schematic diagram of an embodiment of the present invention. As shown in the figure, a low-carbon emission pipeline combustion-driven compressor unit control system includes a main fuel supply pipe 1 and a low-carbon fuel pipe 2. The inlet of the main fuel supply pipe 1 is connected to a blended fuel supply pipe 3, and the outlet is connected to a gas turbine body fuel supply pipe 4. The main fuel supply pipe 1 is provided with a natural gas pre-stop valve 11, a natural gas separator 12, a natural gas post-stop valve 13, and a natural gas regulating valve 14 in sequence from the inlet to the outlet. The inlet of the low-carbon fuel pipe 2 is connected to the main fuel supply pipe 1 at the inlet end of the natural gas pre-stop valve 11, and the outlet of the low-carbon fuel pipe 2 is connected to the main fuel supply pipe 1 at the outlet end of the natural gas regulating valve 14. The low-carbon fuel pipe 2 is provided with a first low-carbon fuel stop valve 21, a second low-carbon fuel stop valve 22, and a low-carbon fuel regulating valve 23 in sequence from the inlet to the outlet.

[0033] By setting up the main fuel supply pipe 1, fuel can be supplied to the gas turbine; by setting up the low-carbon fuel pipe 2, blended fuel can be supplied to the gas turbine after fuel switching; by setting up the natural gas pre-stop valve 11, the on / off state of the main fuel supply pipe 1 can be controlled; by setting up the natural gas separator 12, blended fuel can be separated, and pure natural gas can be separated and supplied to the gas turbine through the main fuel supply pipe 1, so that the gas turbine can start stably and reduce the difficulty of starting; by setting up the natural gas post-stop valve 13, it can work in conjunction with the natural gas pre-stop valve 11 to control the on / off state of the main fuel supply pipe 1; by setting up the natural gas pre-stop valve 12, the on / off state of the main fuel supply pipe 1 can be controlled; by setting up the natural gas pre-stop valve 13, the on / off state of the main fuel supply pipe 1 can be controlled; by setting up the natural gas pre-stop valve 12, the on / off state of the main fuel supply pipe 1 can be controlled; by setting up the natural gas pre-stop valve 13, the on / off state of the main fuel supply pipe 1 can be controlled; by setting up the natural gas pre-stop valve 12, the on / off state of the main fuel supply pipe 1 can be controlled; by setting up the natural gas pre-stop valve 12, the on / off state of the main fuel supply pipe 1 can be controlled; by setting up the natural gas pre-stop valve 12, the on / off state of the main fuel supply pipe 12 ... The natural gas regulating valve 14 can adjust its opening degree during fuel switching to control and reduce the pure natural gas flow supply of the main fuel supply pipe 1 until it is completely closed. By setting a first low-carbon fuel shut-off valve 21, it can control the on / off of the low-carbon fuel pipe 2. By setting a second low-carbon fuel shut-off valve 22, it can cooperate with the first low-carbon fuel shut-off valve 21 to control the on / off of the low-carbon fuel pipe 2. By setting a low-carbon fuel regulating valve 23, it can adjust its opening degree during fuel switching to control and increase the flow supply of blended fuel in the low-carbon fuel pipe 2. In conjunction with the natural gas regulating valve 14, it can achieve stable fuel switching.

[0034] A first discharge pipe 5 is provided on the main fuel supply pipe 1 between the natural gas separator 12 and the natural gas downstream shut-off valve 13, and a second discharge pipe 6 is provided on the main fuel supply pipe 1 between the natural gas downstream shut-off valve 13 and the natural gas regulating valve 14. By setting the first discharge pipe 5 and the second discharge pipe 6, all residual combustible gases in the pipeline and in the natural gas separator 12 can be removed before switching fuels.

[0035] The first discharge pipe 5 is equipped with a first vent valve 51, and the second discharge pipe 6 is equipped with a second vent valve 61. By setting the first vent valve 51 and the second vent valve 61, the on / off state of the first discharge pipe 5 and the second discharge pipe 6 can be controlled respectively.

[0036] A third discharge pipe 7 is provided on the low-carbon fuel pipe 2 between the first low-carbon fuel shut-off valve 21 and the second low-carbon fuel shut-off valve 22, and a fourth discharge pipe 8 is provided on the low-carbon fuel pipe 2 between the second low-carbon fuel shut-off valve 22 and the low-carbon fuel regulating valve 23. By setting the third discharge pipe 7 and the fourth discharge pipe 8, the pipeline can be filled in conjunction with the first low-carbon fuel shut-off valve 21 to prevent the pipeline from being delayed and causing fluctuations in operating conditions. After shutdown, the mixed fuel in the low-carbon fuel pipe 2 can be vented.

[0037] The third discharge pipe 7 is equipped with a third vent valve 71, and the fourth discharge pipe 8 is equipped with a fourth vent valve 81. By setting the third vent valve 71 and the fourth vent valve 81, the on / off state of the third discharge pipe 7 and the fourth discharge pipe 8 can be controlled respectively.

[0038] Natural gas inlet shut-off valve 11, natural gas outlet shut-off valve 13, first low-carbon fuel shut-off valve 21, second low-carbon fuel shut-off valve 22, first vent valve 51, second vent valve 61, third vent valve 71, and fourth vent valve 81 are all solenoid valves, while natural gas regulating valve 14 and low-carbon fuel regulating valve 23 are both electric valves. By setting solenoid valves with fast opening or closing speeds, the pipeline can be opened or closed quickly; by setting electric valves, the valve opening degree can be controlled.

[0039] The natural gas separator 12 is equipped with a separation pipeline. The first discharge pipe 5, the second discharge pipe 6, the third discharge pipe 7, the fourth discharge pipe 8, and the exhaust end of the separation pipeline are all located within a safe emission area. By setting up the separation pipeline, the separated hydrogen gas can be discharged.

[0040] like Figure 2 As shown, a control method for a low-carbon emission pipeline combustion-driven compressor unit includes the following steps:

[0041] S1. Gas generator turning gear start control: The output power of the hydraulic motor installed on the gas generator is controlled by controlling the supply of high-pressure hydraulic oil. The hydraulic motor drives the gas generator to start up to 20% of the rated speed.

[0042] S2. Gas generator turning gear purging control: Through proportional-integral regulation, the gas generator is controlled to operate stably at 20% of the rated speed for 1.5 times the air flow channel replacement time. That is, at the current speed, the total volume of air discharged by the gas generator is equal to 1.5 times the volume of the space where the gas-driven compressor unit and the main flow inside the gas generator are connected. At the same time as the gas generator is purging, the natural gas front shut-off valve 11 and the natural gas separator 12 are opened to remove all residual combustible gas.

[0043] S3. Gas generator ignition control: By first reducing and then increasing the supply of high-pressure hydraulic oil, the power of the hydraulic motor is first reduced and then increased, so that the speed of the gas generator is reduced to 15% of the rated speed, first decelerating and then increasing; during the speed increase process, the first vent valve 51 and the second vent valve 61 are closed, the natural gas after-stop valve 13 is opened, and the natural gas regulating valve 14 is controlled to give a fixed amount of natural gas fuel within the range of 15% to 25% of the rated speed of the gas generator, which is introduced into the fuel supply pipe 4 of the gas turbine body;

[0044] S4. Gas Generator Ignition Speed-Up Control: Based on the fixed natural gas fuel quantity given in step S3, and according to the deviation between the current speed and the idle speed, the fuel increment is calculated using a proportional-integral formula to obtain the fuel quantity for the gas turbine. The opening of the natural gas regulating valve 14 is controlled according to changes in fuel demand, gradually increasing the opening of the natural gas regulating valve 14. During the speed-up process, when 45% of the rated speed is reached, the high-pressure hydraulic oil supply is reduced, separating the hydraulic motor from the gas generator, allowing the gas generator speed-up to be driven entirely by the heat generated from the combustion of natural gas fuel. The proportional-integral formula is:

[0045]

[0046] In the formula: W represents the fuel increment from the previous time step after priority selection. f For fuel increment, K is the proportional gain parameter, which is a fixed parameter. I The integral gain parameter is a fixed parameter; Δ is the difference between the current speed and the idle speed; τ is the number of control logic operations that have been performed; and t is the current number of operations.

[0047] S5. Gas generator idle speed self-sustaining operation control: After accelerating to the gas generator idle speed (approximately 70% of the rated speed), according to the proportional-integral calculation formula in S4, the fuel increment will fluctuate around a small value, thereby maintaining the gas generator at idle speed; control the speed to idle speed and run for 5-10 minutes to warm up, while opening the first low-carbon fuel shut-off valve 21 and the third vent valve 71 to inject hydrogen and natural gas blended fuel into the low-carbon fuel pipe 2 to fill the pipeline and prevent pipeline delivery delays from causing fluctuations in operating conditions;

[0048] S6. Low-carbon fuel switching: After warm-up, begin switching to low-carbon fuel. After closing the fourth vent valve 81, open the second low-carbon fuel shut-off valve 22. Then, control the low-carbon fuel regulating valve 23 to open from the fully closed state, and simultaneously control the natural gas regulating valve 14 to close from its current opening position. At the start of low-carbon fuel switching, first calculate the current fuel supply heat based on the current natural gas supply. Divide the current fuel supply heat by the calorific value of the low-carbon fuel to obtain the target flow rate required for a complete switch to low-carbon fuel. Simultaneously, calculate the limit value of the current hydrogen increment based on the loop difference and non-uniformity characteristics of the temperature measuring points arranged circumferentially at the compressor outlet and gas generator outlet. Then, the increment per second at 1% of the target flow rate is compared with the limit value of hydrogen increment, and the smaller value is taken as the current increment of low-carbon fuel. During the low-carbon fuel switching process, the increment of low-carbon fuel is continuously accumulated to obtain the current supply of low-carbon fuel, which corresponds to the opening degree of low-carbon fuel regulating valve 23. The decrease in natural gas is the same as the heat of the increase in low-carbon fuel, which corresponds to the opening degree of natural gas regulating valve 14. The natural gas regulating valve 14 is gradually closed until it is completely closed, and then the natural gas front shut-off valve 11 and the natural gas rear shut-off valve 13 are closed. Then, the first vent valve 51 and the second vent valve 61 are opened, and at the same time, the natural gas separator 12 stops working, and the fuel switching ends.

[0049] S7. Power Turbine No-Load Speed ​​Increase: After completing the low-carbon fuel switch, the target speed of the power turbine is manually set to the no-load speed value, and the target speed of the gas generator is set to the safe speed limit value of 105% of the rated speed. According to the proportional-integral calculation formula in S4, the corresponding data is replaced, and the fuel increment obtained based on the difference between the current gas generator and power turbine speeds and the target speeds is calculated. Based on the ring difference and non-uniformity characteristics of the circumferential temperature measurement points at the compressor outlet and gas generator outlet, the limit value of the current hydrogen increment is calculated to obtain the limit value of the low-carbon fuel increment. The minimum value of the three is compared, and the minimum value is then compared with the maximum value of the current low-carbon fuel shutdown fuel limit value. Finally, the fuel increment that drives the gas generator to speed up is obtained, and the increased high-temperature and high-pressure gas flow from the gas generator drives the power turbine to speed up to the no-load speed.

[0050] S8. Compressor load regulation: After the power turbine reaches the no-load speed, the manual operation sets the target value of the coaxial speed of the power turbine and compressor required for the final gas compression and delivery production. The compressor speed is automatically increased through the same low-carbon fuel regulation method as the power turbine no-load speed increase, to reach the final production speed.

[0051] S9. Speed ​​Reduction Shutdown: When performing a normal shutdown under low-carbon fuel operation, firstly, the speed is reduced from the normal operating speed to the no-load condition of the power turbine. During the reduction, only the target value of the power turbine speed is changed from the production speed to the no-load speed; the target speed of the gas generator remains at the safety limit. Based on the difference between the power turbine speed and the target value, the fuel reduction is calculated using the proportional-integral formula in S4. This is then compared with the minimum difference between the current gas generator speed and the limit for hydrogen combustion shutdown, and the fuel reduction is performed at the minimum amount. Secondly, the speed is reduced from the no-load condition of the power turbine to the idle condition of the gas generator. At this time, the speed is... The target speed of the gas generator is changed to idle speed, and the minimum difference between this speed and the limit value of hydrogen combustion shutdown is compared. The fuel is reduced by the minimum amount. After the speed drops to idle speed, the operation is maintained for 5 to 10 minutes. Finally, the fuel supply is directly cut off at idle speed, the first low-carbon fuel shut-off valve 21, the second low-carbon fuel shut-off valve 22 and the low-carbon fuel regulating valve 23 are closed, and the third vent valve 71 and the fourth vent valve 81 are opened, so that the gas turbine can automatically shut down. After supplying high-pressure hydraulic oil at 20% turning speed for 15 minutes of turning, the speed is finally reduced to zero, and the shutdown is completed.

[0052] This invention is applicable to the start-up, operation, and shutdown control of pipeline gas-driven compressor units used in the production of hydrogen and natural gas blended with low-carbon fuels. It provides a reliable control method for the production operation of gas-driven compressor units using low-carbon fuels with different hydrogen content ratios, thereby solving the instability problems that exist during the start-up, ignition, operation, and shutdown processes when using low-carbon fuels. This invention is applicable to all scenarios where gas turbines drive gas booster compressors using a dual-shaft structure consisting of a gas generator and a power turbine. Currently, all gas-driven compressor units used in my country are of this type.

[0053] The descriptions of the orientation or relative positional relationships of the structures in this invention, such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inner", and "outer", are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the structure referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

Claims

1. A control method for a low-carbon emission pipeline fuel-driven compressor unit, applied to a control system for a low-carbon emission pipeline fuel-driven compressor unit, the control system for the low-carbon emission pipeline fuel-driven compressor unit includes a main fuel supply pipe (1) and a low-carbon fuel pipe (2), the main fuel supply pipe (1) being provided with a natural gas pre-stop valve (11), a natural gas separator (12), a natural gas post-stop valve (13) and a natural gas regulating valve (14) in sequence from the inlet to the outlet, the inlet of the low-carbon fuel pipe (2) being connected to the main fuel supply pipe (1) at the inlet end of the natural gas pre-stop valve (11), the outlet of the low-carbon fuel pipe (2) being connected to the main fuel supply pipe (1) at the outlet end of the natural gas regulating valve (14), the low-carbon fuel pipe (2) being provided with a first low-carbon fuel stop valve (21), a second low-carbon fuel stop valve (22) and a low-carbon fuel regulating valve (23) in sequence from the inlet to the outlet, characterized in that, Includes the following steps: S1. Gas generator turning gear start control: The output power of the hydraulic motor installed on the gas generator is controlled by controlling the supply of high-pressure hydraulic oil. The hydraulic motor drives the gas generator to start to 20% to 30% of the rated speed. S2. Gas generator turning gear cleaning control: By using the proportional-integral regulation method, the gas generator is controlled to operate stably at 20% to 30% of the rated speed for 1.5 to 2 times the air flow channel replacement time. At the same time as the gas generator is cleaning, the natural gas front shut-off valve (11) and the natural gas separator (12) are opened. S3, Ignition control of gas generator: By first reducing and then increasing the supply of high-pressure hydraulic oil, the power of the hydraulic motor is first reduced and then increased, so that the speed of the gas generator is first reduced and then increased; and during the speed increase process, the discharge pipe on the main fuel supply pipe (1) is closed, the natural gas shut-off valve (13) is opened at the same time, and the natural gas regulating valve (14) is controlled to give a fixed amount of natural gas fuel within the range of 15% to 25% of the rated speed of the gas generator; S4. Speed-up control after gas generator ignition: Based on the fixed amount of natural gas fuel given in step S3, the fuel increment is calculated by using the proportional-integral formula according to the deviation between the current speed and the idle speed to obtain the fuel quantity of the gas turbine. The opening of the natural gas regulating valve (14) is controlled according to the change in fuel quantity demand, and the opening of the natural gas regulating valve (14) is gradually increased. During the speed-up process, the hydraulic motor is separated from the gas generator, and the gas generator speed-up is driven entirely by the heat generated by the combustion of natural gas fuel. S5. Gas generator slow speed self-sustaining operation control: After speeding up to the gas generator slow speed, control the speed to the slow speed and warm up the machine. Open the first low-carbon fuel shut-off valve (21) and at the same time open the discharge pipe between the first low-carbon fuel shut-off valve (21) and the second low-carbon fuel shut-off valve (22) to inject hydrogen and natural gas mixed fuel into the low-carbon fuel pipe (2) to fill the pipeline. S6. Low-carbon fuel switching: After the warm-up is completed, start switching to low-carbon fuel. After closing the discharge pipe between the second low-carbon fuel shut-off valve (22) and the low-carbon fuel regulating valve (23), open the second low-carbon fuel shut-off valve (22). Then control the low-carbon fuel regulating valve (23) to start opening from the fully closed state. At the same time, control the natural gas regulating valve (14) to start closing from the current opening state. Gradually close the natural gas regulating valve (14) until it is completely closed. Then close the natural gas front shut-off valve (11) and the natural gas rear shut-off valve (13). Then open the discharge pipe on the main fuel supply pipe (1). At the same time, the natural gas separator (12) stops working. The fuel switching is over. S7. Power Turbine No-Load Speed ​​Increase: After completing the low-carbon fuel switch, the target speed of the power turbine is set to the no-load speed value, and the target speed of the gas generator is set to the safe speed limit value of 100% to 110% of the rated speed; the increased high-temperature and high-pressure gas flow from the gas generator drives the power turbine to increase its speed to the no-load speed. S8. Compressor load regulation: After the power turbine reaches the no-load speed, set the target value of the coaxial speed of the power turbine and compressor required for the final gas compression and delivery production. The compressor speed is automatically increased through the same low-carbon fuel regulation method as the power turbine no-load speed increase, to reach the final production speed. S9. Speed ​​Reduction Shutdown: When performing a normal shutdown under low-carbon fuel operation, first reduce the operating speed to the power turbine no-load condition, then reduce the power turbine no-load condition to the gas generator idle condition. After reducing to idle speed, maintain operation for 5-10 minutes. Finally, cut off the fuel supply directly at idle speed, close the first low-carbon fuel shut-off valve (21), the second low-carbon fuel shut-off valve (22) and the low-carbon fuel regulating valve (23), and open the discharge pipe on the low-carbon fuel pipe (2) to automatically shut down the gas turbine. After supplying high-pressure hydraulic oil at 20%-30% turning speed for 10-15 minutes of turning, the speed is finally reduced to zero, and the shutdown is completed.

2. The control method for low-carbon emission pipeline combustion-driven compressor units according to claim 1, characterized in that, A first discharge pipe (5) is provided on the main fuel supply pipe (1) between the natural gas separator (12) and the natural gas downstream shut-off valve (13), and a second discharge pipe (6) is provided on the main fuel supply pipe (1) between the natural gas downstream shut-off valve (13) and the natural gas regulating valve (14).

3. The control method for low-carbon emission pipeline combustion-driven compressor units according to claim 2, characterized in that, The first discharge pipe (5) is equipped with a first vent valve (51), and the second discharge pipe (6) is equipped with a second vent valve (61).

4. The control method for low-carbon emission pipeline combustion-driven compressor units according to claim 3, characterized in that, A third discharge pipe (7) is provided on the low-carbon fuel pipe (2) between the first low-carbon fuel shut-off valve (21) and the second low-carbon fuel shut-off valve (22), and a fourth discharge pipe (8) is provided on the low-carbon fuel pipe (2) between the second low-carbon fuel shut-off valve (22) and the low-carbon fuel regulating valve (23).

5. The control method for low-carbon emission pipeline combustion-driven compressor units according to claim 4, characterized in that, The third discharge pipe (7) is equipped with a third vent valve (71), and the fourth discharge pipe (8) is equipped with a fourth vent valve (81).

6. The control method for low-carbon emission pipeline combustion-driven compressor units according to claim 5, characterized in that, The natural gas front shut-off valve (11), natural gas rear shut-off valve (13), first low-carbon fuel shut-off valve (21), second low-carbon fuel shut-off valve (22), first vent valve (51), second vent valve (61), third vent valve (71) and fourth vent valve (81) are all solenoid valves, and the natural gas regulating valve (14) and low-carbon fuel regulating valve (23) are both electric valves.

7. The control method for low-carbon emission pipeline combustion-driven compressor units according to claim 6, characterized in that, The natural gas separator (12) is equipped with a separation pipeline.

8. The control method for a low-carbon emission pipeline combustion-driven compressor unit according to claim 1, characterized in that, S6 It also includes: at the start of the low-carbon fuel switch, first calculate the current fuel supply heat based on the current natural gas supply fuel quantity, divide the current fuel supply heat by the heat value of the low-carbon fuel to obtain the target flow rate required when fully switching to low-carbon fuel; at the same time, calculate the current hydrogen increment limit based on the ring difference and non-uniformity characteristics of the temperature measuring points arranged circumferentially at the compressor outlet and gas generator outlet, and then compare the increment per second at 1% of the target flow rate with the hydrogen increment limit value, and take the smaller value as the current low-carbon fuel increment; during the low-carbon fuel switch, continuously accumulate the low-carbon fuel increment to obtain the current low-carbon fuel supply quantity, and obtain the opening degree of the low-carbon fuel regulating valve (23) accordingly. The decrease in natural gas is the same as the heat of the increase in low-carbon fuel, and obtain the opening degree of the natural gas regulating valve (14) accordingly.

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