Fuel switching method and system

Abstract

The invention discloses a fuel switching method and system, relates to the technical field of fuel power generation, and can improve the power supply stability and the operation safety of a power supply unit. The method is applied to a fuel switching system, the system comprises a reciprocating supercharger, a buffer tank set and a gas turbine, a natural gas pipeline is connected with the reciprocating supercharger, the reciprocating supercharger is connected with the buffer tank set, the buffer tank set is connected with the gas turbine, and natural gas is contained in the buffer tank set; the method comprises the steps that after a fuel switching instruction is received, natural gas in a buffer tank set is controlled to be input into a gas turbine, so that the gas turbine completes fuel switching through the natural gas output by the buffer tank set; and when it is detected that the pressure of the buffer tank set is smaller than the preset pressure, natural gas in the natural gas pipeline is filled into the buffer tank set through the reciprocating supercharger till the pressure of the buffer tank set reaches the preset pressure.

Description

Technical Field

[0001] The present application relates to the field of fuel power generation technology, and in particular to a fuel switching method and system. Background Art

[0002] Natural gas-oil combined cycle power generation has the advantages of high thermal efficiency, fast start-up, strong peak-shaving capacity and low pollution, and is an ideal way of power generation. With the increase in gas turbine installed capacity, natural gas is generally used as the main fuel and fuel as the backup fuel. Therefore, when switching fuels, it is necessary to switch in a planned manner. Take the example of switching from burning natural gas to fuel power generation. It is necessary to gradually reduce the load of the gas turbine from the normal load state of burning natural gas, and gradually mix fuel into the gas turbine when the load reaches about 20%. At this time, the natural gas slowly withdraws and switches to complete fuel combustion. After that, the fuel load will be gradually increased to the normal load.

[0003] However, if the above fuel switching system encounters a natural gas pipeline failure and the natural gas supply is suddenly and unplannedly interrupted, the entire generator set cannot operate normally and can only be shut down quickly, and then the fuel is switched to fuel oil for restart. This rapid shutdown process will undoubtedly damage the life of the entire unit and cause certain fluctuations in the power grid. Summary of the invention

[0004] The present application provides a fuel switching method and system, which can improve power supply stability and operational safety of power supply units.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] In a first aspect of an embodiment of the present application, a fuel switching method is provided, which is applied to a fuel switching system, the system comprising: a reciprocating supercharger, a buffer tank group and a fuel engine, wherein a natural gas pipeline is connected to the reciprocating supercharger, the reciprocating supercharger is connected to the buffer tank group, the buffer tank group is connected to the fuel engine, and the buffer tank group is filled with natural gas; the method comprises:

[0007] After receiving the fuel switching instruction, controlling the natural gas in the buffer tank group to be input into the gas engine, so that the gas engine uses the natural gas output from the buffer tank group to complete the fuel switching;

[0008] When it is detected that the pressure of the buffer tank group is lower than the preset pressure, the natural gas in the natural gas pipeline is charged into the buffer tank group by using the reciprocating booster until the pressure of the buffer tank group reaches the preset pressure.

[0009] As a possible implementation, the system further includes: a heater and a pressure regulating valve, and the control of inputting the natural gas in the buffer tank group to the gas engine includes:

[0010] The heater is controlled to heat the natural gas output from the buffer tank group, and the pressure regulating valve is used to adjust the pressure of the heated natural gas before inputting it into the gas engine.

[0011] As a possible implementation manner, the natural gas pipeline is further connected to the buffer tank group, and the method further includes:

[0012] When it is detected that the pressure of the buffer tank group is lower than the output pressure of the natural gas pipeline, the natural gas pipeline is used to charge the buffer tank group with natural gas.

[0013] As a possible implementation, before receiving the fuel switching instruction, the method further includes:

[0014] Obtaining a target consumption of the gas engine, wherein the target consumption is the natural gas consumption of the gas engine during a fuel switching process;

[0015] Determine the target volume of the buffer tank group according to the target consumption, the first density and the second density, wherein the first density is the density of the buffer tank at the first pressure, the second density is the density of the buffer tank at the second pressure, the first pressure is the storage pressure of the buffer tank, and the second pressure is the pressure of the buffer tank after deflation;

[0016] The number of buffer tanks in the buffer tank group is determined according to the target volume and the preset individual volumes of the buffer tanks.

[0017] As a possible implementation manner, obtaining the target consumption of the gas engine includes:

[0018] Obtaining a first consumption of natural gas in the gas engine, and obtaining a second consumption of natural gas in the gas engine, wherein the first consumption is the consumption of natural gas in a process in which the gas engine reduces its load from 100% to 20%, and the second consumption is the consumption of natural gas in a process in which the gas engine burns a mixture of natural gas and fuel oil;

[0019] The target consumption is determined according to the first consumption, the second consumption and a preset number of fuel engines.

[0020] As a possible implementation manner, obtaining the first consumption of natural gas in the gas engine includes:

[0021] Obtaining a first power generation power and a first natural gas consumption of the gas engine at 100% load, and obtaining a second power generation power and a second natural gas consumption of the gas engine at 20% load;

[0022] Determining the time required for the gas engine load to decrease according to the first power generation, the second power generation and a preset gas engine load decrease rate;

[0023] The first consumption is determined according to the first natural gas consumption, the second natural gas consumption and the drop time.

[0024] As a possible implementation manner, obtaining the second consumption of natural gas in the gas engine includes:

[0025] The second consumption is determined according to the second natural gas consumption, a preset switching time and a preset coefficient.

[0026] In a second aspect of the embodiment of the present application, a fuel switching system is provided, the system comprising: a processing device, a reciprocating supercharger, a buffer tank group and a gas engine, wherein a natural gas pipeline is connected to the reciprocating supercharger, the reciprocating supercharger is connected to the buffer tank group, the buffer tank group is connected to the gas engine, and the buffer tank group is filled with natural gas;

[0027] The processing device is used to: after receiving the fuel switching instruction, control the natural gas in the buffer tank group to be input into the gas engine, so that the gas engine uses the natural gas output by the buffer tank group to complete the fuel switching;

[0028] When it is detected that the pressure of the buffer tank group is lower than the preset pressure, the natural gas in the natural gas pipeline is charged into the buffer tank group by using the reciprocating booster until the pressure of the buffer tank group reaches the preset pressure.

[0029] As a possible implementation, the system further includes: a heater and a pressure regulating valve, and the step of inputting the natural gas in the buffer tank group to the gas engine includes:

[0030] The heater is controlled to heat the natural gas output from the buffer tank group, and the pressure regulating valve is used to adjust the pressure of the heated natural gas before inputting it into the gas engine.

[0031] As a possible implementation manner, the natural gas pipeline is further connected to the buffer tank group, and the method further includes:

[0032] When it is detected that the pressure of the buffer tank group is lower than the output pressure of the natural gas pipeline, the natural gas pipeline is used to charge the buffer tank group with natural gas.

[0033] The beneficial effects brought by the technical solution provided by the embodiment of the present application include at least:

[0034] The fuel switching method provided in the embodiment of the present application is applied to a fuel switching system, which includes: a reciprocating supercharger, a buffer tank group and a fuel engine, wherein a natural gas pipeline is connected to the reciprocating supercharger, the reciprocating supercharger is connected to the buffer tank group, the buffer tank group is connected to the fuel engine, and the buffer tank group is filled with natural gas. The method includes: after receiving a fuel switching instruction, controlling the natural gas in the buffer tank group to be input into the fuel engine, so that the fuel engine uses the natural gas output by the buffer tank group to complete the fuel switching; when it is detected that the pressure of the buffer tank group is less than the preset pressure, using the reciprocating supercharger to fill the natural gas in the natural gas pipeline into the buffer tank group until the pressure of the buffer tank group reaches the preset pressure. The fuel switching method provided in the embodiment of the present application, by setting a buffer tank group, uses the natural gas in the buffer tank group to be input into the fuel engine during the fuel switching process, so that the fuel engine can perform fuel switching, which can improve the power supply stability and the operating safety of the power supply unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A structural diagram of a fuel switching system provided in an embodiment of the present application;

[0036] Figure 2 A fuel switching method provided in the embodiment of the present application Figure 1 ;

[0037] Figure 3 A fuel switching method provided in the embodiment of the present application Figure 2 ;

[0038] Figure 4 A structural diagram of a processing device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0041] Additionally, the use of “based on” or “according to” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” or “according to” one or more conditions or values ​​may, in practice, be based on additional conditions or beyond values.

[0042] Natural gas-oil combined cycle power generation has the advantages of high thermal efficiency, fast start-up, strong peak-shaving capacity and low pollution, and is an ideal way of power generation. With the increase in gas turbine installed capacity, natural gas is generally used as the main fuel and fuel as the backup fuel. Therefore, when switching fuels, it is necessary to switch in a planned manner. Take the example of switching from burning natural gas to fuel power generation. It is necessary to gradually reduce the load of the gas turbine from the normal load state of burning natural gas, and gradually mix fuel into the gas turbine when the load reaches about 20%. At this time, the natural gas slowly withdraws and switches to complete fuel combustion. After that, the fuel load will be gradually increased to the normal load.

[0043] However, if the above fuel switching system encounters a natural gas pipeline failure and the natural gas supply is suddenly and unplannedly interrupted, the entire generator set cannot operate normally and can only be shut down quickly, and then the fuel is switched to fuel oil for restart. This rapid shutdown process will undoubtedly damage the life of the entire unit and cause certain fluctuations in the power grid.

[0044] In order to ensure the safety of unit operation and prevent power grid fluctuations, the unit must have the ability to switch fuel online without stopping. To do this, a natural gas buffer system needs to be set up to provide sufficient natural gas reserves for the unit to complete the fuel switching process.

[0045] In order to solve the above problems, the present application embodiment provides a fuel switching system, such as Figure 1 As shown, the system includes: a reciprocating supercharger 40, a buffer tank group 20 and a gas engine 30. The natural gas pipeline is connected to the reciprocating supercharger 40, the reciprocating supercharger 40 is connected to the buffer tank group 20, the buffer tank group 20 is connected to the gas engine 30, and the buffer tank group 20 is filled with natural gas.

[0046] Based on Figure 1 The fuel switching system shown in the figure, the embodiment of the present application also provides a fuel switching method, such as Figure 2 As shown, the method comprises the following steps:

[0047] Step 201: After receiving a fuel switching instruction, control the natural gas in the buffer tank group to be input into the gas engine, so that the gas engine uses the natural gas output from the buffer tank group to complete the fuel switching.

[0048] The fuel switching instruction is used to instruct switching from natural gas to fuel oil. The buffer tank group stores compressed natural gas.

[0049] When no fuel switching command is received, the natural gas in the natural gas pipeline is directly delivered to the gas engine.

[0050] Step 202: When it is detected that the pressure of the buffer tank group is less than the preset pressure, the natural gas in the natural gas pipeline is charged into the buffer tank group by using the reciprocating booster until the pressure of the buffer tank group reaches the preset pressure.

[0051] The preset pressure is the pressure after the buffer tank group is fully stored with natural gas, and the preset pressure may be 110 bar.g.

[0052] The fuel switching method provided in the embodiment of the present application is applied to a fuel switching system, which includes: a reciprocating supercharger, a buffer tank group and a fuel engine, wherein a natural gas pipeline is connected to the reciprocating supercharger, the reciprocating supercharger is connected to the buffer tank group, the buffer tank group is connected to the fuel engine, and the buffer tank group is filled with natural gas. The method includes: after receiving a fuel switching instruction, controlling the natural gas in the buffer tank group to be input into the fuel engine, so that the fuel engine uses the natural gas output by the buffer tank group to complete the fuel switching; when it is detected that the pressure of the buffer tank group is less than the preset pressure, using the reciprocating supercharger to fill the natural gas in the natural gas pipeline into the buffer tank group until the pressure of the buffer tank group reaches the preset pressure. The fuel switching method provided in the embodiment of the present application, by setting a buffer tank group, uses the natural gas in the buffer tank group to be input into the fuel engine during the fuel switching process, so that the fuel engine can perform fuel switching, which can improve the power supply stability and the operating safety of the power supply unit.

[0053] Optionally, the system further includes: a heater and a pressure regulating valve. The step 201 described in the above-mentioned step of controlling the natural gas in the buffer tank group to be input to the gas turbine includes:

[0054] The heater is controlled to heat the natural gas output from the buffer tank group, and the pressure regulating valve is used to adjust the pressure of the heated natural gas before inputting it into the gas engine.

[0055] When the buffer tank supplies gas to the gas turbine, the natural gas output by the buffer tank group is heated by the water jacket furnace heater to offset the temperature drop of the natural gas after pressure regulation, so as to ensure the temperature requirement of the natural gas after pressure regulation; then the pressure is reduced to 18.5~46.9bar.g through the pneumatic pressure regulating valve and sent to the downstream pipeline to supply gas to the gas turbine.

[0056] Optionally, the natural gas pipeline is also connected to the buffer tank group, and the method further includes: when it is detected that the pressure of the buffer tank group is lower than the output pressure of the natural gas pipeline, using the natural gas pipeline to charge the buffer tank group with natural gas.

[0057] Optional, such as Figure 3As shown, before receiving the fuel switching instruction in step 201, the method further includes the following steps:

[0058] Step 301: Obtain the target consumption of the gas engine, where the target consumption is the natural gas consumption of the gas engine during the fuel switching process.

[0059] Step 302: Determine the target volume of the buffer tank group according to the target consumption, the first density and the second density, wherein the first density is the density of the buffer tank at the first pressure, the second density is the density of the buffer tank at the second pressure, the first pressure is the storage pressure of the buffer tank, and the second pressure is the pressure of the buffer tank after being deflated.

[0060] The first pressure may be a storage pressure of 110 bar.g, and the second pressure may be 23.5 bar.g.

[0061] Step 303: Determine the number of buffer tanks in the buffer tank group according to the target volume and the preset individual volume of the buffer tank.

[0062] It is understandable that before setting up the buffer tank group in the fuel switching system, it is necessary to first determine the volume of the buffer tank group or the number of buffer tanks in the buffer tank group, and configure the buffer tank group according to the determined number of buffer tanks.

[0063] For example, the target consumption can be represented by B, then the target volume

[0064] Wherein, ρ1 is the first density, ρ2 is the second density, and γ is the volume margin coefficient, which can be 110%. After determining the target volume V, it is known that the single volume of each buffer tank can be 33.63m 3 , so the number of buffer tanks in the buffer tank group can be determined.

[0065] Specifically, the step 301 of obtaining the target consumption of the gas engine includes:

[0066] Obtaining a first consumption of natural gas in the gas engine, and obtaining a second consumption of natural gas in the gas engine, wherein the first consumption is the consumption of natural gas in a process in which the gas engine reduces its load from 100% to 20%, and the second consumption is the consumption of natural gas in a process in which the gas engine burns a mixture of natural gas and fuel oil;

[0067] The target consumption is determined according to the first consumption, the second consumption and a preset number of fuel engines.

[0068] For example, the target consumption B=(B1+B2)*n, where B1 is the first consumption, B2 is the second consumption, and n is the number of combustion engines.

[0069] Furthermore, obtaining the first consumption of natural gas in the gas engine includes:

[0070] Obtaining a first power generation power and a first natural gas consumption of the gas engine at 100% load, and obtaining a second power generation power and a second natural gas consumption of the gas engine at 20% load;

[0071] Determining the time required for the gas engine load to decrease according to the first power generation, the second power generation and a preset gas engine load decrease rate;

[0072] The first consumption is determined according to the first natural gas consumption, the second natural gas consumption and the drop time.

[0073] For example, B1=(Q 100 +Q 20 ) / 2*T1, T1=(P 100 -P 20 ) / V. Among them, Q 100 is the first natural gas consumption, Q 20 is the second natural gas consumption, T1 is the above-mentioned decline time, P 100 is the first power generation, P 20 is the second power generation power, and V is the rate of decrease of the gas turbine load.

[0074] Optionally, the obtaining of the second consumption of natural gas in the gas engine includes:

[0075] The second consumption is determined according to the second natural gas consumption, a preset switching time and a preset coefficient.

[0076] For example, B2 = Q 20 *0.5*T2. T2 is the switching time mentioned above, and the switching time is the time to complete the switch from natural gas to fuel oil.

[0077] The present application also provides a fuel switching system. Figure 1 As shown, the system includes: a processing device 10, a reciprocating supercharger 40, a buffer tank group 20 and a gas engine 30, wherein a natural gas pipeline is connected to the reciprocating supercharger 40, the reciprocating supercharger 40 is connected to the buffer tank group 20, the buffer tank group 20 is connected to the gas engine 30, and the buffer tank group 20 is filled with natural gas;

[0078] The processing device 10 is used to: after receiving the fuel switching instruction, control the natural gas in the buffer tank group 20 to be input into the gas engine 30, so that the gas engine 30 completes the fuel switching by using the natural gas output by the buffer tank group 20;

[0079] When it is detected that the pressure of the buffer tank group 20 is lower than the preset pressure, the reciprocating booster 40 is used to charge the natural gas in the natural gas pipeline into the buffer tank group 20 until the pressure of the buffer tank group 20 reaches the preset pressure.

[0080] In one embodiment, the system further comprises: a heater and a pressure regulating valve, and the processing device 10 is specifically used for:

[0081] After the heater is controlled to heat the natural gas output from the buffer tank group 20 , the pressure regulating valve is used to adjust the pressure of the heated natural gas and then the natural gas is input to the gas engine 30 .

[0082] In one embodiment, the natural gas pipeline is also connected to the buffer tank group 20, and the processing device 10 is also used for:

[0083] When it is detected that the pressure of the buffer tank group 20 is lower than the output pressure of the natural gas pipeline, the natural gas pipeline is used to fill the buffer tank group 20 with natural gas.

[0084] In one embodiment, the processing device 10 is further used for:

[0085] Obtaining a target consumption of the gas engine 30, wherein the target consumption is the natural gas consumption of the gas engine 30 during the fuel switching process;

[0086] Determine the target volume of the buffer tank group 20 according to the target consumption, the first density and the second density, wherein the first density is the density of the buffer tank at the first pressure, the second density is the density of the buffer tank at the second pressure, the first pressure is the storage pressure of the buffer tank, and the second pressure is the pressure of the buffer tank after deflation;

[0087] The number of buffer tanks in the buffer tank group 20 is determined according to the target volume and the preset individual volumes of the buffer tanks.

[0088] In one embodiment, the processing device 10 is specifically used for:

[0089] Obtaining a first consumption of natural gas in the gas engine 30, and obtaining a second consumption of natural gas in the gas engine 30, wherein the first consumption is the consumption of natural gas in a process in which the gas engine 30 decreases from 100% load to 20% load, and the second consumption is the consumption of natural gas in a process in which the gas engine 30 is mixed with natural gas and fuel for combustion;

[0090] The target consumption is determined according to the first consumption, the second consumption and the preset number of combustion engines 30 .

[0091] In one embodiment, the processing device 10 is specifically used for:

[0092] Obtaining a first power generation and a first natural gas consumption of the gas engine 30 at 100% load, and obtaining a second power generation and a second natural gas consumption of the gas engine 30 at 20% load;

[0093] Determine the load reduction time required for the gas engine 30 to reduce the load according to the first power generation, the second power generation and a preset load reduction rate of the gas engine 30;

[0094] The first consumption is determined according to the first natural gas consumption, the second natural gas consumption and the drop time.

[0095] In one embodiment, the processing device 10 is specifically used for:

[0096] The second consumption is determined according to the second natural gas consumption, a preset switching time and a preset coefficient.

[0097] The processing device in the fuel switching system provided in this embodiment can execute the above-mentioned fuel switching method embodiment, and its implementation principle and technical effect are similar, which will not be elaborated here.

[0098] For the specific definition of the fuel switching system, please refer to the definition of the fuel switching method above, which will not be repeated here. Each module in the processing device in the above-mentioned fuel switching system can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor of the electronic device in the form of hardware, or can be stored in the memory of the electronic device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0099] The execution entity of the fuel switching method provided in the embodiment of the present application may be a processing device. Figure 4 This is a schematic diagram of the internal structure of a processing device provided in an embodiment of the present application. Figure 4 As shown, the processing device includes a processor and a memory connected via a system bus. The processing device is used to provide computing and control capabilities. The memory may include a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The computer program can be executed by the processor to implement the steps of the fuel switching method provided in each of the above embodiments. The internal memory provides a cache operating environment for the operating system and the computer program in the non-volatile storage medium.

[0100] Those skilled in the art will understand that Figure 4The internal structure diagram of the processing device shown in the figure is only a block diagram of a partial structure related to the present application scheme, and does not constitute a limitation on the processing device to which the present application scheme is applied. The specific processing device may include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0101] In another embodiment of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the fuel switching method in the embodiment of the present application are implemented.

[0102] In another embodiment of the present application, a computer program product is provided. The computer program product includes computer instructions. When the computer instructions execute the various steps of the fuel switching method in the method flow shown in the above method embodiment.

[0103] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using a software program, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loading and executing computer execution instructions on a computer, the process or function according to the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. Computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, computer instructions can be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server, data center, etc. that contains one or more servers that can be integrated with a medium. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0104] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A fuel switching method, characterized in that: Applied to a fuel switching system, the system comprises: a reciprocating supercharger, a buffer tank group and a gas engine, wherein a natural gas pipeline is connected to the reciprocating supercharger, the reciprocating supercharger is connected to the buffer tank group, the buffer tank group is connected to the gas engine, and the buffer tank group is filled with natural gas; the method comprises: After receiving the fuel switching instruction, controlling the natural gas in the buffer tank group to be input into the gas engine, so that the gas engine uses the natural gas output from the buffer tank group to complete the fuel switching; When it is detected that the pressure of the buffer tank group is lower than the preset pressure, the natural gas in the natural gas pipeline is charged into the buffer tank group by using the reciprocating booster until the pressure of the buffer tank group reaches the preset pressure.

2. The method according to claim 1, characterized in that The system further comprises: a heater and a pressure regulating valve, and the control of inputting the natural gas in the buffer tank group to the combustion engine comprises: The heater is controlled to heat the natural gas output from the buffer tank group, and the pressure regulating valve is used to adjust the pressure of the heated natural gas before inputting it into the gas engine.

3. The method according to claim 1, characterized in that The natural gas pipeline is also connected to the buffer tank group, and the method further includes: When it is detected that the pressure of the buffer tank group is lower than the output pressure of the natural gas pipeline, the natural gas pipeline is used to charge the buffer tank group with natural gas.

4. The method according to claim 1, characterized in that: Before receiving the fuel switching instruction, the method further includes: Obtaining a target consumption of the gas engine, wherein the target consumption is the natural gas consumption of the gas engine during a fuel switching process; Determine the target volume of the buffer tank group according to the target consumption, the first density and the second density, wherein the first density is the density of the buffer tank at the first pressure, the second density is the density of the buffer tank at the second pressure, the first pressure is the storage pressure of the buffer tank, and the second pressure is the pressure of the buffer tank after deflation; The number of buffer tanks in the buffer tank group is determined according to the target volume and the preset individual volumes of the buffer tanks.

5. The method according to claim 4, characterized in that The obtaining of the target consumption of the gas engine comprises: Obtaining a first consumption of natural gas in the gas engine, and obtaining a second consumption of natural gas in the gas engine, wherein the first consumption is the consumption of natural gas in a process in which the gas engine reduces its load from 100% to 20%, and the second consumption is the consumption of natural gas in a process in which the gas engine burns a mixture of natural gas and fuel oil; The target consumption is determined according to the first consumption, the second consumption and a preset number of fuel engines.

6. The method according to claim 5, characterized in that The obtaining of the first consumption of natural gas in the gas engine comprises: Obtaining a first power generation and a first natural gas consumption of the gas engine at 100% load, and obtaining a second power generation and a second natural gas consumption of the gas engine at 20% load; Determining the time required for the gas engine load to decrease according to the first power generation, the second power generation and a preset gas engine load decrease rate; The first consumption is determined according to the first natural gas consumption, the second natural gas consumption and the falling time.

7. The method according to claim 6, characterized in that The obtaining of the second consumption of natural gas in the gas engine comprises: The second consumption is determined according to the second natural gas consumption, a preset switching time and a preset coefficient.

8. A fuel switching system, characterized in that: The system comprises: a processing device, a reciprocating supercharger, a buffer tank group and a gas engine, wherein a natural gas pipeline is connected to the reciprocating supercharger, the reciprocating supercharger is connected to the buffer tank group, the buffer tank group is connected to the gas engine, and the buffer tank group is filled with natural gas; The processing device is used to: after receiving the fuel switching instruction, control the natural gas in the buffer tank group to be input into the gas engine, so that the gas engine uses the natural gas output by the buffer tank group to complete the fuel switching; When it is detected that the pressure of the buffer tank group is lower than the preset pressure, the natural gas in the natural gas pipeline is charged into the buffer tank group by using the reciprocating booster until the pressure of the buffer tank group reaches the preset pressure.

9. The system according to claim 8, characterized in that The system further comprises: a heater and a pressure regulating valve, and the natural gas in the buffer tank group is input to the combustion engine, comprising: The heater is controlled to heat the natural gas output from the buffer tank group, and the pressure regulating valve is used to adjust the pressure of the heated natural gas before inputting it into the gas engine.

10. The system according to claim 8, characterized in that The natural gas pipeline is also connected to the buffer tank group, and the method further includes: When it is detected that the pressure of the buffer tank group is lower than the output pressure of the natural gas pipeline, the natural gas pipeline is used to charge the buffer tank group with natural gas.

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