Purging system, gasification furnace and purging control method

Abstract

The invention provides a purging system, a gasification furnace and a purging control method. Wherein the purging system comprises a purging structure, and the purging structure is used for purging a preset position; the communicating structure is provided with a first gas inlet end, a second gas inlet end, a gas outlet end and a communicating cavity, the first gas inlet end is communicated with the first gas supply structure, the second gas inlet end is communicated with the second gas supply structure, the first gas supply structure supplies nitrogen, and the second gas supply structure supplies carbon dioxide gas; the control valve assembly comprises a first control valve and a second control valve, the first control valve is used for controlling the first air inlet end to be communicated or disconnected, and the second control valve is used for controlling the second air inlet end to be communicated or disconnected; when the gasification furnace main body starts to operate, the first gas inlet end is communicated, and the second gas inlet end is disconnected; and when the gasification furnace main body stably operates, the first gas inlet end is disconnected, and the second gas inlet end is communicated. The problems that in the prior art, a GSP gasification furnace system is high in operation energy consumption and poor in operation safety are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of gasifiers, and in particular to a purge system, a gasifier and a purge control method. Background Art

[0002] At present, during the operation of the GSP gasifier system, high-pressure nitrogen is mainly used as the purge gas for purge during the start-up phase, while fresh gas is used as the purge gas for purge during the normal operation phase. The main purposes of the purge operation are: 1. Purge the space between the back side of the water-cooled wall of the gasifier and the pressure jacket to prevent dust accumulation and protect the water-cooled wall from corrosion; 2. Purge the gap between the burner support device and the burner to prevent high-temperature gas from passing through; 3. Purge the pressure-taking pipelines of the two quenching water nozzles in the quenching chamber to prevent blockage of the pressure-taking pipelines.

[0003] However, fresh gas is actually the raw material for synthesizing methanol. Using fresh gas as purge gas will increase the consumption of fresh gas, which in turn leads to higher operating energy consumption of the GSP gasifier. On the other hand, the main components of fresh gas are carbon monoxide and hydrogen, which are flammable, thus affecting the operating safety of the GSP gasifier. Summary of the invention

[0004] The main purpose of the present invention is to provide a purge system, a gasifier and a purge control method to solve the problems of high operating energy consumption and poor operating safety of the GSP gasifier system in the prior art.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a purging system is provided, comprising: a purging structure, arranged in a gasifier body, for purging a preset position; a connecting structure, having a first air inlet end, a second air inlet end, an air outlet end and a connecting cavity, the air outlet end is connected to the first air inlet end and the second air inlet end through the connecting cavity, the air outlet end is connected to the purging structure, the first air inlet end is connected to the first air supply structure, the second air inlet end is connected to the second air supply structure, the first air supply structure is used to supply nitrogen, and the second air supply structure is used to supply carbon dioxide gas; a control valve assembly, arranged on the connecting structure, the control valve assembly comprises a first control valve and a second control valve, the first control valve is used to control the first air inlet end to be connected or disconnected, and the second control valve is used to control the second air inlet end to be connected or disconnected; wherein, when the gasifier body starts to run, the first air inlet end is connected, and the second air inlet end is disconnected; when the gasifier body runs stably, the first air inlet end is disconnected, and the second air inlet end is connected.

[0006] Furthermore, the control valve assembly also includes: a third control valve, which is arranged between the second control valve and the second air inlet end, and the third control valve is used to control at least one of the pressure, flow rate, or flow rate of the carbon dioxide gas flowing through the third control valve.

[0007] Furthermore, the connecting structure also has a third air inlet end, which is connected to the air outlet end through a connecting cavity, and the third air inlet end is connected to a third air supply structure, which is used to supply a mixed gas, wherein the mixed gas is a mixture of carbon monoxide gas and hydrogen.

[0008] Furthermore, the control valve assembly also includes a fourth control valve, and the fourth control valve is used to control the connection or disconnection of the third air inlet end.

[0009] Furthermore, the purge system also includes: a detection device, which is arranged on the gasifier body, and the detection device is used to detect the gas pressure value in the gasifier body; a control module, which is connected to the detection device, the first control valve and the second control valve, and the control module controls the opening of the first control valve according to the detection value of the detection device; and / or the control module controls the opening of the second control valve according to the detection value of the detection device.

[0010] Furthermore, the connecting structure is tubular and includes: a first pipeline, the two ends of the first pipeline are respectively a first air inlet end and an air outlet end; a third pipeline, connected to the first pipeline, the first connecting point between the third pipeline and the first pipeline is located between the first air inlet end and the air outlet end, the first control valve is arranged on the first pipeline and is located between the first connecting point and the first air inlet end, and the end of the third pipeline away from the first pipeline is the third air inlet end; a second pipeline, connected to the third pipeline, the second connecting point between the second pipeline and the third pipeline is located between the first connecting point and the third air inlet end, the fourth control valve is located between the second connecting point and the third air inlet end, and the second control valve and the third control valve are both arranged on the second pipeline.

[0011] Furthermore, the second gas supply structure is a carbon dioxide delivery pipeline of the pulverized coal delivery pipeline of the gasifier body.

[0012] According to another aspect of the present invention, a gasifier is provided. The gasifier includes a gasifier body and a purge system arranged on the gasifier body. The purge system is the purge system described above.

[0013] According to another aspect of the present invention, a purge control method is provided. The purge control method is applicable to the above-mentioned gasifier, and the purge control method comprises:

[0014] Step S1: when the gasifier body of the gasifier starts to operate, the first control valve of the purge system of the gasifier is opened, and the second control valve, the third control valve and the fourth control valve of the purge system are all closed;

[0015] Step S2: After the internal pressure value of the gasifier body reaches the first preset value A1, the first gas supply structure of the purge system is opened, and the third control valve is opened to the first working state;

[0016] Step S3: After the gas pressure value at the third control valve reaches the second preset value A2, the second control valve is opened, and the third control valve is opened to the second working state;

[0017] Step S4: After the gas pressure value at the third control valve reaches the third preset value A3, the third control valve is opened to the third working state, and the first control valve is closed.

[0018] Further, the first preset value A1 satisfies: 3.6 MPa≤A1≤4.0 MPa, the second preset value A2 satisfies: 4.3 MPa≤A2≤4.7 MPa, and the third preset value A3 satisfies: 4.5 MPa≤A3≤5 MPa.

[0019] According to the technical solution of the present invention, the purge structure of the purge system is arranged in the main body of the gasifier to purge the preset position. The connecting structure has a first air inlet end, a second air inlet end, an air outlet end and a connecting cavity. The air outlet end is connected to the first air inlet end and the second air inlet end through the connecting cavity. The air outlet end is connected to the purge structure. The first air inlet end is connected to the first air supply structure, and the second air inlet end is connected to the second air supply structure. The first air supply structure is used to supply nitrogen, and the second air supply structure is used to supply carbon dioxide gas. The control valve assembly is arranged on the connecting structure and includes a first control valve and a second control valve. The first control valve is used to control the connection or disconnection of the first air inlet end, and the second control valve is used to control the connection or disconnection of the second air inlet end. When the main body of the gasifier starts to run, the first air inlet end is connected and the second air inlet end is disconnected; when the main body of the gasifier runs stably, the first air inlet end is disconnected and the second air inlet end is disconnected. In this way, the purge system in this application actually uses carbon dioxide with relatively stable chemical properties as the purge medium during the stable operation of the gasifier to replace the "fresh gas" in the prior art. While reducing the operating energy consumption of the gasifier, it can avoid the safety problems caused by the flammable "fresh gas", thereby solving the problem of high operating energy consumption and poor operating safety of the GSP gasifier system in the prior art. At the same time, in the "start-up phase" (the phase of starting operation) of the gasifier, this application still uses nitrogen with a more stable chemical medium as the purge medium for purge, so as to ensure that the gasifier has a sufficiently high reaction stability during the initial feeding reaction, thereby improving the product quality of the gasifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 It shows a schematic diagram of the overall structure of an embodiment of a purge system according to the present invention;

[0022] Figure 2 A flow chart showing an embodiment of a purge control method according to the present invention is shown.

[0023] The above drawings include the following reference numerals:

[0024] 10. Connecting structure; 11. First air inlet end; 12. Second air inlet end; 13. Air outlet end; 14. Third air inlet end; 15. First pipeline; 16. Second pipeline; 17. Third pipeline;

[0025] 20. Control valve assembly; 21. First control valve; 22. Second control valve; 23. Third control valve; 24. Fourth control valve. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0027] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0028] In the present invention, unless otherwise specified, the directional words used, such as "up" and "down", usually refer to the directions shown in the drawings, or to the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "left" and "right" usually refer to the left and right shown in the drawings; "inside" and "outside" refer to the inside and outside relative to the outline of each component itself, but the above directional words are not used to limit the present invention.

[0029] In order to solve the problems of high operating energy consumption and poor operating safety of the GSP gasifier system in the prior art, the present application provides a purge system, a gasifier and a purge control method.

[0030] like Figure 1As shown, the purge system includes: a purge structure, which is arranged in the gasifier body and is used to purge a preset position; a connecting structure 10, which has a first air inlet end 11, a second air inlet end 12, an air outlet end 13 and a connecting cavity, the air outlet end 13 is connected to the first air inlet end 11 and the second air inlet end 12 through the connecting cavity, the air outlet end 13 is connected to the purge structure, the first air inlet end 11 is connected to the first air supply structure, the second air inlet end 12 is connected to the second air supply structure, the first air supply structure is used to supply nitrogen, and the second air supply structure is used to supply dioxygen carbonized gas; a control valve assembly 20 is arranged on the connecting structure 10, the control valve assembly 20 includes a first control valve 21 and a second control valve 22, the first control valve 21 is used to control the first air inlet end 11 to be connected or disconnected, and the second control valve 22 is used to control the second air inlet end 12 to be connected or disconnected; wherein, when the gasifier body starts to run, the first air inlet end 11 is connected and the second air inlet end 12 is disconnected; when the gasifier body is running stably, the first air inlet end 11 is disconnected and the second air inlet end 12 is connected.

[0031] According to the technical solution of this embodiment, the purge structure of the purge system is arranged in the gasifier body to purge the preset position. The connecting structure has a first air inlet end 11, a second air inlet end 12, an air outlet end 13 and a connecting cavity. The air outlet end 13 is connected to the first air inlet end 11 and the second air inlet end 12 through the connecting cavity. The air outlet end 13 is connected to the purge structure. The first air inlet end 11 is connected to the first air supply structure, and the second air inlet end 12 is connected to the second air supply structure. The first air supply structure is used to supply nitrogen, and the second air supply structure is used to supply carbon dioxide. The control valve assembly 20 is arranged on the connecting structure 10 and includes a first control valve 21 and a second control valve 22. The first control valve 21 is used to control the first air inlet end 11 to be connected or disconnected, and the second control valve 22 is used to control the second air inlet end 12 to be connected or disconnected. When the gasifier body starts to run, the first air inlet end 11 is connected and the second air inlet end 12 is disconnected; when the gasifier body is running stably, the first air inlet end 11 is disconnected and the second air inlet end 12 is connected. In this way, the purge system in this embodiment actually uses carbon dioxide with relatively stable chemical properties as the purge medium during the operation of the gasifier to replace the "fresh gas" in the prior art. While reducing the operating energy consumption of the gasifier, it can avoid the safety problems caused by the flammable "fresh gas", thereby solving the problem of high operating energy consumption and poor operating safety of the GSP gasifier system in the prior art. At the same time, in the "start-up phase" (the phase when the operation just starts) of the gasifier, this embodiment still uses nitrogen with a more stable chemical medium as the purge medium for purge, so as to ensure that the gasifier has a sufficiently high reaction stability during the initial feeding reaction, thereby improving the product quality of the gasifier.

[0032] Optionally, the purge structure is a nozzle.

[0033] Optionally, the first air supply structure is an air supply device.

[0034] In this embodiment, there are at least four purge structures, and there are also at least four corresponding gas outlets 13 . The at least four gas outlets 13 are arranged in one-to-one correspondence with the at least four purge structures.

[0035] In this embodiment, four purge structures are used to purge the space between the water-cooled wall and the pressure jacket, and the gap between the burner support and the burners, respectively.

[0036] In this embodiment, the first control valve 21 and the second control valve 22 are both cut-off valves.

[0037] In this embodiment, the control valve assembly 20 further includes: a third control valve 23, which is arranged between the second control valve 22 and the second air inlet end 12, and the third control valve 23 is used to control at least one of the pressure, flow rate, or flow rate of the carbon dioxide gas flowing through the third control valve 23. In this way, the arrangement of the third control valve 23 can adjust the pressure of the carbon dioxide gas to ensure that the pressure value of the carbon dioxide gas purged into the gasifier body through the purging structure is relatively appropriate, thereby improving the operating stability of the purging structure (that is, if the pressure of the carbon dioxide gas is insufficient, there is a possibility that purging cannot be performed), ensuring that the pressure inside the gasifier body is relatively stable, thereby improving the operating stability of the gasifier.

[0038] Specifically, the above arrangement can also prevent the pressure of the carbon dioxide gas from being too high and damaging the water-cooled wall, thereby extending the service life of the gasifier.

[0039] Optionally, the third control valve 23 is a pressure reducing valve.

[0040] In this embodiment, the connecting structure 10 also has a third air inlet end 14, which is connected to the air outlet end 13 through a connecting cavity, and the third air inlet end 14 is connected to a third air supply structure, which is used to supply a mixed gas, wherein the mixed gas is a mixture of carbon monoxide gas and hydrogen. In this way, the above-mentioned setting actually retains the original "fresh gas" purge pipeline of the gasifier, that is, the purge system in this embodiment can be directly improved on the original purge system to reduce the setting cost of the purge system. At the same time, the original "fresh gas" purge pipeline can also play the role of emergency purge, thereby avoiding damage to the carbon dioxide supply pipeline of the purge system, which causes the gasifier to be shut down for maintenance, and further improves the operating stability of the gasifier.

[0041] In this embodiment, the control valve assembly 20 further includes a fourth control valve 24, which is used to control the connection or disconnection of the third air inlet end 14. In this way, the above arrangement can control the connection state of the third air inlet end 14 (i.e., the supply state of "fresh air") to ensure that "fresh air" is not supplied when the carbon dioxide gas is purged normally.

[0042] Optionally, the purge system further includes: a detection device, which is arranged on the gasifier body, and is used to detect the gas pressure value in the gasifier body; a control module, which is connected to the detection device, the first control valve 21 and the second control valve 22, and the control module controls the opening of the first control valve 21 according to the detection value of the detection device; and / or the control module controls the opening of the second control valve 22 according to the detection value of the detection device. In this way, by controlling the operating states of the first control valve 21 and the second control valve 22 through the control module, the automation and intelligence of the gasifier system can be improved, thereby reducing the labor intensity of the staff.

[0043] like Figure 1 As shown, the connecting structure 10 is tubular and includes: a first pipeline 15, the two ends of the first pipeline 15 are the first air inlet end 11 and the air outlet end 13 respectively; a third pipeline 17, which is connected with the first pipeline 15, the first connecting point between the third pipeline 17 and the first pipeline 15 is located between the first air inlet end 11 and the air outlet end 13, the first control valve 21 is arranged on the first pipeline 15 and is located between the first connecting point and the first air inlet end 11, and the end of the third pipeline 17 away from the first pipeline 15 is the third air inlet end 14; a second pipeline 16, which is connected with the third pipeline 17, the second connecting point between the second pipeline 16 and the third pipeline 17 is located between the first connecting point and the third air inlet end 14, the fourth control valve 24 is located between the second connecting point and the third air inlet end 14, and the second control valve 22 and the third control valve 23 are both arranged on the second pipeline 16. In this way, the above arrangement makes the structure of the connecting structure 10 simpler, easier to process and realize; on the other hand, the position setting of each control valve ensures that the function of each control valve can be realized normally.

[0044] In this embodiment, the second gas supply structure is the carbon dioxide delivery pipeline of the coal powder delivery pipeline of the gasifier body. In this way, in fact, the second gas supply structure in this embodiment is the second carbon dioxide delivery pipeline of the original coal powder delivery pipeline of the gasifier, that is, the purge system does not need to be additionally provided with a carbon dioxide gas supply structure, further reducing the installation cost of the purge system.

[0045] Specifically, for some gasifiers, the pulverized coal in the pulverized coal conveying pipeline is conveyed by the carbon dioxide gas conveyed from the carbon dioxide conveying pipeline. This embodiment uses the carbon dioxide gas in the original carbon dioxide conveying pipeline of the gasifier as the purge medium, which can greatly reduce the setting cost of the purge system.

[0046] Specifically, the carbon dioxide gas in the carbon dioxide transmission pipeline is actually the carbon dioxide generated during the operation of the gasifier. Therefore, in the initial operation of the gasifier, the carbon dioxide gas generated by the gasifier is insufficient and the pressure cannot meet the corresponding demand. Therefore, this embodiment controls the switching state of the control valve in different operation periods of the gasifier body to ensure that the pressure value of the carbon dioxide gas introduced into the gasifier body can meet the corresponding demand.

[0047] This embodiment further provides a gasifier, which includes a gasifier body and a purge system arranged on the gasifier body, and the purge system is the purge system mentioned above.

[0048] This embodiment also provides a purge control method, such as Figure 2 As shown, the purge control method is applicable to the above-mentioned gasifier, and the purge control method includes:

[0049] Step S1: when the gasifier body of the gasifier starts to operate, the first control valve 21 controlling the purge system of the gasifier is opened, and the second control valve 22, the third control valve 23 and the fourth control valve 24 controlling the purge system are all closed;

[0050] Step S2: After the internal pressure value of the gasifier body reaches the first preset value A1, the first gas supply structure of the purge system is opened, and the third control valve 23 is opened to the first working state;

[0051] Step S3: After the gas pressure value at the third control valve 23 reaches the second preset value A2, the second control valve 22 is opened, and the third control valve 23 is opened to the second working state;

[0052] Step S4: after the gas pressure value at the third control valve 23 reaches the third preset value A3, the third control valve 23 is opened to the third working state, and the first control valve 21 is closed.

[0053] In this way, the above operation steps can ensure that the pressure value of the carbon dioxide gas introduced into the gasifier body is not only relatively stable, but also can meet the operation requirements of the gasifier.

[0054] Optionally, the first preset value A1 satisfies: 3.6 MPa≤A1≤4.0 MPa, the second preset value A2 satisfies: 4.3 MPa≤A2≤4.7 MPa, and the third preset value A3 satisfies: 4.5 MPa≤A3≤5 MPa.

[0055] In this embodiment, the first preset value A1 is 3.8 MPa, and the second preset value A2 is 4.5 MPa.

[0056] In this embodiment, the operating pressure of the gasifier is 5 MPa.

[0057] Specifically, the first working state, the second working state and the third working state are all working states under different pressure control values ​​and different openings of the pressure reducing valve (third control valve 23), that is, at the initial operation stage of the gasifier body, the gasifier fails to produce enough carbon dioxide gas, and the internal reaction state has not tended to be stable, so nitrogen is first introduced into the gasifier body until the gas pressure value in the gasifier body reaches 3.8Mpa, and then the pressure control value of the third control valve 23 is set to 4.5Mpa, and the opening is maintained at about 5% (the first working state). Since the amount of carbon dioxide gas generated at this time is insufficient (the gas pressure is low), the second control valve 22 is still in a closed state to prevent the high-pressure gas in the gasifier body from flowing back until After the gas pressure value at the third control valve 23 reaches 4.5Mpa (that is, the amount of carbon dioxide gas generated can meet the pressure control requirements, and the gasifier body tends to be in a stable operating state), the second control valve 22 is opened to introduce carbon dioxide gas into the gasifier body. At the same time, the pressure control value of the third control valve 23 is increased (set between 4.5Mpa and 5Mpa, and the opening is further increased, the second working state) to ensure that the pressure in the gasifier body can be stably increased. After the gas pressure value at the third control valve 23 reaches the increased pressure value (the internal pressure value of the gasifier body tends to be stable and officially enters a stable operating state), the first control valve 21 can be completely closed and the third control valve 23 can be fully opened (the third working state).

[0058] Specifically, the above operation can prevent the high-pressure gas of the gasifier body from flowing back into the carbon dioxide delivery pipeline through the purge structure while ensuring the gas pressure value in the gasifier body to rise steadily, thereby greatly improving the operating stability of the gasifier.

[0059] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0060] The purge structure of the purge system is arranged in the gasifier body to purge the preset position. The connecting structure has a first air inlet end, a second air inlet end, an air outlet end and a connecting cavity. The air outlet end is connected to the first air inlet end and the second air inlet end through the connecting cavity. The air outlet end is connected to the purge structure. The first air inlet end is connected to the first air supply structure, and the second air inlet end is connected to the second air supply structure. The first air supply structure is used to supply nitrogen, and the second air supply structure is used to supply carbon dioxide gas. The control valve assembly is arranged on the connecting structure and includes a first control valve and a second control valve. The first control valve is used to control the connection or disconnection of the first air inlet end, and the second control valve is used to control the connection or disconnection of the second air inlet end. Wherein, when the gasifier body starts to run, the first air inlet end is connected and the second air inlet end is disconnected; when the gasifier body runs stably, the first air inlet end is disconnected and the second air inlet end is connected. In this way, the purge system in this application actually uses carbon dioxide with relatively stable chemical properties as the purge medium during the operation of the gasifier to replace the "fresh gas" in the prior art. While reducing the operating energy consumption of the gasifier, it can avoid the safety problems caused by the flammable "fresh gas", thereby solving the problem of high operating energy consumption and poor operating safety of the GSP gasifier system in the prior art. At the same time, in the "start-up phase" (the phase when the operation just starts) of the gasifier, this application still uses nitrogen with a more stable chemical medium as the purge medium for purge, so as to ensure that the gasifier has a sufficiently high reaction stability during the initial feeding reaction, thereby improving the product quality of the gasifier.

[0061] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0062] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0063] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A purge system, characterized in that: include: A purge structure is arranged in the gasifier body to purge a preset position; A connecting structure (10) comprising a first air inlet end (11), a second air inlet end (12), an air outlet end (13) and a connecting cavity, wherein the air outlet end (13) is connected to the first air inlet end (11) and the second air inlet end (12) through the connecting cavity, the air outlet end (13) is connected to the purge structure, the first air inlet end (11) is connected to a first air supply structure, the second air inlet end (12) is connected to a second air supply structure, the first air supply structure is used to supply nitrogen gas, and the second air supply structure is used to supply carbon dioxide gas; a control valve assembly (20) disposed on the communication structure (10), the control valve assembly (20) comprising a first control valve (21) and a second control valve (22), the first control valve (21) being used to control the connection or disconnection of the first air inlet end (11), and the second control valve (22) being used to control the connection or disconnection of the second air inlet end (12); Wherein, when the gasifier body starts to operate, the first air inlet end (11) is connected and the second air inlet end (12) is disconnected; when the gasifier body operates stably, the first air inlet end (11) is disconnected and the second air inlet end (12) is connected.

2. The purge system according to claim 1, characterized in that: The control valve assembly (20) further comprises: A third control valve (23) is arranged between the second control valve (22) and the second air inlet end (12), and the third control valve (23) is used to control at least one of the pressure, flow rate, or flow rate of the carbon dioxide gas flowing through the third control valve (23).

3. The purge system according to claim 2, characterized in that: The connecting structure (10) further comprises a third air inlet end (14), wherein the third air inlet end (14) is connected to the air outlet end (13) via the connecting cavity, and the third air inlet end (14) is connected to a third air supply structure, wherein the third air supply structure is used to supply a mixed gas, wherein the mixed gas is a mixture of carbon monoxide gas and hydrogen.

4. The purge system according to claim 3, characterized in that: The control valve assembly (20) further comprises a fourth control valve (24), wherein the fourth control valve (24) is used to control the connection or disconnection of the third air inlet end (14).

5. The purge system according to claim 1, characterized in that: The purge system also includes: A detection device, disposed on the gasifier body, and used to detect the gas pressure value in the gasifier body; A control module is connected to the detection device, the first control valve (21) and the second control valve (22), and the control module controls the opening of the first control valve (21) according to the detection value of the detection device; and / or the control module controls the opening of the second control valve (22) according to the detection value of the detection device.

6. The purge system according to claim 4, characterized in that: The communication structure (10) is tubular and comprises: A first pipeline (15), wherein two ends of the first pipeline (15) are respectively the first air inlet end (11) and the air outlet end (13); a third pipeline (17) connected to the first pipeline (15); a first connection point between the third pipeline (17) and the first pipeline (15) is located between the first air inlet end (11) and the air outlet end (13); the first control valve (21) is arranged on the first pipeline (15) and is located between the first connection point and the first air inlet end (11); an end of the third pipeline (17) away from the first pipeline (15) is the third air inlet end (14); The second pipeline (16) is connected to the third pipeline (17); the second connection point between the second pipeline (16) and the third pipeline (17) is located between the first connection point and the third air inlet end (14); the fourth control valve (24) is located between the second connection point and the third air inlet end (14); and the second control valve (22) and the third control valve (23) are both arranged on the second pipeline (16).

7. The purge system according to claim 1, characterized in that: The second gas supply structure is a carbon dioxide delivery pipeline of the pulverized coal delivery pipeline of the gasifier body.

8. A gasifier, characterized in that: The gasifier comprises a gasifier body and a purge system arranged on the gasifier body, and the purge system is the purge system according to any one of claims 1 to 7.

9. A purge control method, characterized in that: The purge control method is applicable to the gasifier described in claim 8, and the purge control method comprises: Step S1: when the gasifier body of the gasifier starts to operate, the first control valve (21) of the purge system of the gasifier is opened, and the second control valve (22), the third control valve (23) and the fourth control valve (24) of the purge system are all closed; Step S2: after the internal pressure value of the gasifier body reaches a first preset value A1, the first air supply structure of the purge system is opened, and the third control valve (23) is opened to a first working state; Step S3: After the gas pressure value at the third control valve (23) reaches a second preset value A2, the second control valve (22) is opened, and the third control valve (23) is opened to a second working state; Step S4: After the gas pressure value at the third control valve (23) reaches a third preset value A3, the third control valve (23) is opened to a third working state, and the first control valve (21) is closed.

10. The purge control method according to claim 9, characterized in that: The first preset value A1 satisfies: 3.6 MPa≤A1≤4.0 MPa, the second preset value A2 satisfies: 4.3 MPa≤A2≤4.7 MPa, and the third preset value A3 satisfies: 4.5 MPa≤A3≤5 MPa.

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