Low concentration gas combustion device and system

Abstract

The application provides a low-concentration gas combustion device and system, and belongs to the field of low-concentration gas combustion. The device comprises a low-concentration gas conveying pipe, an auxiliary gas conveying pipe, a flue gas conveying pipe, an oxidation combustion device, an exhaust cylinder, an air conveying pipe and a control device. The oxidation combustion device comprises an oxidation combustion chamber, is used for mixing input low-concentration gas and auxiliary gas into mixed combustion gas, and outputs flue gas generated by combustion of the mixed combustion gas to the flue gas conveying pipe through a flue gas outlet. The air conveying pipe is used for inputting air to the auxiliary gas conveying pipe. The flue gas circulating pipe is used for inputting part of flue gas output by the flue gas conveying pipe to the auxiliary gas conveying pipe, and inputting auxiliary gas formed by mixing air and flue gas in the auxiliary gas conveying pipe to the oxidation combustion chamber. The control device is used for adjusting the ratio of flue gas flow and air flow within a set proportion range. The method provided by the application can improve the heat energy efficiency of the oxidation combustion device and reduce the concentration of nitrogen oxides generated by combustion.

Description

Technical Field

[0001] This invention relates to the field of low-concentration gas combustion technology, specifically to a low-concentration gas combustion device and a low-concentration gas combustion system. Background Technology

[0002] With the continuous introduction of environmental protection policies and coal mine gas management policies, coal mine gas has gradually transformed from "direct emission into atmosphere" to "rational utilization", truly realizing "turning waste into treasure".

[0003] Coal mine gas can be mainly classified into high-concentration gas and low-concentration gas based on its concentration. High-concentration gas typically refers to gas with a methane volume content of 30% or higher. This type of gas has many uses, such as: grid connection for internal combustion engine power generation, utilization in gas-fired boilers, and production and sale of CNG or LNG. Low-concentration gas typically refers to gas with a methane volume content of 8% to 30%. This type of gas is usually used for grid connection for internal combustion engine power generation.

[0004] In existing internal combustion engine oxidation combustion devices, low-concentration gas is mixed with air, and the oxygen in the air is used to assist the combustion of low-concentration gas. However, the input air temperature is low, the heat energy generated by the oxidation combustion device is low, the gas utilization efficiency is low, and the input air margin is too large, resulting in a high concentration of nitrogen oxides produced by combustion. Summary of the Invention

[0005] To address the technical problems of low heat energy generated and high nitrogen oxide concentration in existing oxidation combustion devices, this invention provides a low-concentration gas combustion device and a low-concentration gas combustion system. Using this low-concentration gas combustion device can increase the temperature of the air input to the oxidation combustion device, further increasing the heat energy generated by the oxidation combustion device, improving gas utilization efficiency, reducing air margin, and lowering the concentration of nitrogen oxides generated during combustion.

[0006] To achieve the above objectives, a first aspect of the present invention provides a low-concentration gas combustion device comprising: a low-concentration gas supply pipe for inputting low-concentration gas; an auxiliary gas supply pipe for inputting auxiliary gas; a flue gas supply pipe for outputting flue gas; and an oxidation combustion device including an oxidation combustion chamber; the oxidation combustion chamber having a gas inlet, an auxiliary gas inlet, and a flue gas outlet, wherein the gas inlet is connected to the low-concentration gas supply pipe, the auxiliary gas inlet is connected to the auxiliary gas supply pipe, and the flue gas outlet is connected to the flue gas supply pipe; the oxidation combustion chamber is used to mix the input low-concentration gas with the auxiliary gas to form a mixed combustion gas, and to output the flue gas generated by the combustion of the mixed combustion gas to the flue gas supply pipe through the flue gas outlet; an exhaust stack disposed at the outlet of the flue gas supply pipe for discharging flue gas; and an air supply pipe connected to the auxiliary gas supply pipe for inputting air into the auxiliary gas supply pipe, wherein the air supply pipe is equipped with an air flow meter and an air flow valve, the air flow meter being used for... An air flow meter is used to detect the air flow rate in the air supply pipe and generate an air flow rate signal. The air flow valve is used to adjust the air flow rate in the air supply pipe. A flue gas recirculation pipe is installed between the flue gas supply pipe and the auxiliary supply pipe. It is used to input a portion of the flue gas output from the flue gas supply pipe into the auxiliary supply pipe, and to input the auxiliary gas formed by the mixture of air and flue gas into the oxidation combustion chamber through the auxiliary supply pipe. The flue gas recirculation pipe is equipped with a recirculating flue gas flow meter and a recirculating flue gas flow valve. The recirculating flue gas flow meter is used to detect the flue gas flow rate in the flue gas recirculation pipe and generate a flue gas flow rate signal. The recirculating flue gas flow valve is used to adjust the flue gas flow rate in the flue gas recirculation pipe. A control device is connected to the air flow meter, the air flow valve, the recirculating flue gas flow meter, and the recirculating flue gas flow valve. It is used to control the opening degree of the recirculating flue gas flow valve and the air flow valve according to the received air flow rate signal and the flue gas flow rate signal, so as to adjust the ratio of flue gas flow rate to air flow rate within a set ratio range.

[0007] Furthermore, the oxidation combustion chamber also includes an air distribution valve, on which the gas inlet, auxiliary gas inlet, and flue gas outlet are integrated.

[0008] Furthermore, the flue gas transmission pipe also includes: a methane detection instrument, used to detect the methane content of the flue gas transported by the flue gas circulation pipe and output a methane content signal; the flue gas circulation pipe also includes: a quick shut-off valve; the control device is connected to the quick shut-off valve and the methane detection instrument, used to determine the current methane content of the flue gas based on the received methane content signal, and control the quick shut-off valve to shut off when the current methane content is greater than a set content.

[0009] Furthermore, the flue gas recirculation pipe also includes a shut-off valve for opening or closing the flue gas recirculation pipe.

[0010] Furthermore, the flue gas recirculation pipe also includes: an oxygen content detection instrument, used to detect the oxygen content of the flue gas transported by the flue gas recirculation pipe and generate an oxygen content signal; the control device is connected to the oxygen content detection instrument and is used to control the opening of the circulating flue gas flow valve according to the received oxygen content signal, so as to control the oxygen content of the flue gas transported by the flue gas recirculation pipe within a set range.

[0011] Furthermore, the oxidation combustion device also includes a heat storage chamber for storing the heat energy generated during the combustion of the mixed combustion gases inside the oxidation combustion chamber.

[0012] Furthermore, the low-concentration gas pipeline also includes a gas concentration detection instrument for detecting the content of gas input into the low-concentration gas pipeline.

[0013] Furthermore, the flue gas conveying pipe also includes a flue gas flow meter for detecting the flow rate of the flue gas conveyed by the flue gas conveying pipe.

[0014] Furthermore, the circulating flue gas flow valve and the air flow valve are explosion-proof flow valves.

[0015] A second aspect of the present invention provides a low-concentration gas combustion system, including the low-concentration gas combustion device described above.

[0016] The present invention has at least the following technical effects through the technical solution provided by the present invention:

[0017] The low-concentration gas combustion device of the present invention includes an oxidation combustion device and an exhaust stack. The oxidation combustion device has a gas inlet, an auxiliary gas inlet, and a flue gas outlet. The gas inlet is connected to a low-concentration gas supply pipe, the auxiliary gas inlet is connected to an auxiliary supply pipe, and the flue gas outlet is connected to a flue gas supply pipe. The oxidation combustion chamber is used to mix the input low-concentration gas with the auxiliary gas to form a mixed combustion gas, and outputs the flue gas generated by the combustion of the mixed combustion gas through the flue gas outlet to the flue gas supply pipe, and then discharges it into the atmosphere through the exhaust stack. An air supply pipe is connected to the auxiliary supply pipe and inputs air into the auxiliary supply pipe. A flue gas recirculation pipe is set between the flue gas supply pipe and the auxiliary supply pipe, and is used to input a portion of the flue gas output from the flue gas supply pipe into the auxiliary supply pipe, and input the auxiliary gas formed by the mixture of air and flue gas into the oxidation combustion chamber through the auxiliary supply pipe. The temperature of the flue gas discharged after combustion is used to raise the temperature of the input auxiliary gas, increase the heat energy generated by combustion, and at the same time reduce the input air margin. The control device is connected to the air flow meter and air flow valve of the air supply pipe, and the circulating flue gas flow meter and circulating flue gas flow valve of the flue gas circulation pipe. It controls the opening degree of the circulating flue gas flow valve and the air flow valve based on the received air flow signal and flue gas flow signal, thereby adjusting the ratio of flue gas flow to air flow within a set range. The low-concentration gas combustion device provided by this invention can increase the temperature of the air input to the oxidation combustion device, further increasing the heat energy generated by the oxidation combustion device, improving gas utilization efficiency, reducing air margin, and lowering the concentration of nitrogen oxides produced by combustion.

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a schematic diagram of a low-concentration gas combustion device provided in an embodiment of the present invention.

[0021] Explanation of reference numerals in the attached figures

[0022] 1-Low-concentration methane gas supply pipe; 2-Auxiliary gas supply pipe; 3-Flue gas supply pipe; 4-Oxidation combustion device; 5-Exhaust stack; 6-Air supply pipe; 7-Flue gas circulation pipe; 8-Control device; 101-Methane concentration detection instrument; 102-Methane flow meter; 201-Auxiliary gas fan; 202-Inlet port pipe; 301-Methane detection instrument; 302-Flue gas flow meter; 303-Flue gas diversion interface; 304-Flue gas fan; 401-Oxidation combustion chamber; 402-Methane inlet; 403-Auxiliary gas inlet; 404-Flue gas outlet; 405-Air distribution valve; 406-Heat storage chamber; 601-Air flow meter; 602-Air flow valve; 701-Circulating flue gas flow meter; 702-Circulating flue gas flow valve; 703-Quick shut-off valve; 704-Shut-off valve; 705-Oxygen content detection instrument. Detailed Implementation

[0023] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0025] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used to describe the relative positions of components in relation to the directions shown in the accompanying drawings or in relation to the vertical, perpendicular, or gravitational directions.

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] Please refer to Figure 1The first aspect of this invention provides a low-concentration gas combustion device, comprising: a low-concentration gas supply pipe 1 for inputting low-concentration gas; an auxiliary gas supply pipe 2 for inputting auxiliary gas; a flue gas supply pipe 3 for outputting flue gas; and an oxidation combustion device 4, including an oxidation combustion chamber 401. The oxidation combustion chamber 401 has a gas inlet 402, an auxiliary gas inlet 403, and a flue gas outlet 404. The gas inlet 402 is connected to the low-concentration gas supply pipe 1, the auxiliary gas inlet 403 is connected to the auxiliary gas supply pipe 2, and the flue gas outlet 404... The gas outlet 404 is connected to the flue gas supply pipe 3. The oxidation combustion chamber 401 is used to mix the input low-concentration gas with the auxiliary gas to form a mixed combustion gas, and output the flue gas generated by the combustion of the mixed combustion gas to the flue gas supply pipe 3 through the gas outlet 404. The exhaust stack 5 is set at the outlet of the flue gas supply pipe 3 and is used to discharge the flue gas. The air supply pipe 6 is connected to the auxiliary air supply pipe 2 and is used to input air into the auxiliary air supply pipe 2. The air supply pipe 6 is equipped with an air flow meter 601 and an air flow valve 602. The meter 601 is used to detect the air flow rate of the air supply pipe and generate an air flow rate signal. The air flow valve 602 is used to adjust the air flow rate of the air supply pipe. The flue gas circulation pipe 7 is located between the flue gas supply pipe 3 and the auxiliary gas supply pipe 2. It is used to input part of the flue gas output from the flue gas supply pipe 3 into the auxiliary gas supply pipe 2, and to input the auxiliary gas formed by the mixture of air and flue gas into the oxidation combustion chamber 401 through the auxiliary gas supply pipe 2. The flue gas circulation pipe 7 is equipped with a circulating flue gas flow meter 701 and a circulating flue gas flow valve 702. The air flow meter 701 is used to detect the flue gas flow rate of the flue gas circulation pipe 7 and generate a flue gas flow rate signal. The circulating flue gas flow valve is used to adjust the flue gas flow rate of the flue gas circulation pipe 7. The control device 8 is connected to the air flow meter 601, the air flow valve 602, the circulating flue gas flow meter 701, and the circulating flue gas flow valve 702. It is used to control the opening degree of the circulating flue gas flow valve 702 and the air flow valve 602 according to the received air flow rate signal and flue gas flow rate signal, so as to adjust the ratio of flue gas flow rate to air flow rate within a set ratio range.

[0028] Specifically, in this embodiment of the invention, the low-concentration gas combustion device includes: a low-concentration gas supply pipe 1, an auxiliary gas supply pipe 2, a flue gas supply pipe 3, an oxidation combustion device 4, and an exhaust stack 5. The oxidation combustion device 4 includes an oxidation combustion chamber 401, which has a gas inlet 402, an auxiliary gas inlet 403, and a flue gas outlet 404. The gas inlet 402 is connected to the low-concentration gas supply pipe 1, the auxiliary gas inlet 403 is connected to the auxiliary gas supply pipe 2, and the flue gas outlet 404 is connected to the flue gas supply pipe 3. Low-concentration gas supply pipe 1 inputs low-concentration gas into oxidation combustion chamber 401, and auxiliary gas supply pipe 2 inputs auxiliary gas into oxidation combustion chamber 401. Oxidation combustion chamber 401 mixes the input low-concentration gas with the auxiliary gas to form a mixed combustion gas, and outputs the flue gas generated by the combustion of the mixed combustion gas through flue gas outlet 404 to flue gas supply pipe 3. Flue gas supply pipe 3 then discharges the flue gas through exhaust pipe 5.

[0029] The low-concentration gas combustion device also includes an air supply pipe 6 and a flue gas recirculation pipe 7. A three-way flue gas diversion interface 303 is provided on the flue gas supply pipe 3. One interface of the flue gas diversion interface 303 is connected to the exhaust stack 5 through the supply pipe, and the other interface is connected to the flue gas recirculation pipe 7, which can deliver part of the flue gas to the flue gas recirculation pipe 7. The air inlet of the auxiliary supply pipe 2 is provided with a three-way air inlet interface pipe 202. The air inlet interface pipe 202 is connected to the air supply pipe 6 and the flue gas recirculation pipe 7 respectively. The auxiliary supply pipe 2 inputs the auxiliary gas formed by mixing air and part of the flue gas into the oxidation combustion chamber 401, which can increase the temperature in the oxidation combustion chamber 401, increase the heat energy generated by gas combustion in the oxidation combustion chamber 401, and improve the gas utilization efficiency. At the same time, the recirculated part of the flue gas can reduce the air margin, reduce the oxygen-air coefficient, and reduce the concentration of nitrogen oxides generated by combustion.

[0030] An air flow meter 601 and an air flow valve 602 are installed on the air supply pipe 6. The air flow meter 601 detects the air flow rate in the air supply pipe and generates an air flow signal, while the air flow valve 602 regulates the air flow rate in the air supply pipe. A circulating flue gas flow meter 701 and a circulating flue gas flow valve 702 are installed on the flue gas recirculation pipe 7. The circulating flue gas flow meter 701 detects the flue gas flow rate in the flue gas recirculation pipe 7 and generates a flue gas flow signal, while the circulating flue gas flow valve regulates the flue gas flow rate in the flue gas recirculation pipe 7. A control device 8 is connected to the air flow meter 601, air flow valve 602, circulating flue gas flow meter 701, and circulating flue gas flow valve 702. Based on the received air flow signal and flue gas flow signal, it controls the opening degree of the circulating flue gas flow valve 702 and the air flow valve 602 to adjust the ratio of flue gas flow rate to air flow rate within a set range. In one possible embodiment, the ratio of flue gas flow rate to air flow rate is less than or equal to 45%.

[0031] The low-concentration gas combustion device provided by the present invention can increase the temperature of the air input to the oxidation combustion device, further increase the heat energy generated by the oxidation combustion device, improve gas utilization efficiency, reduce air margin, and reduce the concentration of nitrogen oxides generated by combustion.

[0032] Furthermore, the oxidation combustion chamber 401 also includes an air distribution valve 405, wherein the gas inlet 402, the auxiliary gas inlet 403, and the flue gas outlet 404 are integrated on the air distribution valve 405.

[0033] Specifically, in this embodiment of the invention, the oxidation combustion chamber 401 further includes an air distribution valve 405, on which a gas inlet 402, an auxiliary gas inlet 403, and a flue gas outlet 404 are integrated. This facilitates centralized control of the inlet and outlet of the oxidation combustion chamber 401, improving control efficiency.

[0034] Furthermore, the flue gas transmission pipe 3 also includes: a methane detection instrument 301, used to detect the methane content of the flue gas transported by the flue gas circulation pipe 7 and output a methane content signal; the flue gas circulation pipe 7 also includes: a quick shut-off valve 703; the control device 8 is connected to the quick shut-off valve 703 and the methane detection instrument 301, used to determine the current methane content of the flue gas according to the received methane content signal, and control the quick shut-off valve 703 to shut off when the current methane content is greater than the set content.

[0035] Specifically, in this embodiment of the invention, due to incomplete mixing of the input gas, the gas may not burn completely in the oxidation combustion chamber 401, resulting in some gas remaining in the discharged flue gas. To prevent excessive gas discharge, which could lead to excessive gas content circulating back to the oxidation combustion chamber 401 and exceed the standard concentration of gas mixed with auxiliary gas, a methane detector 301 is installed on the flue gas supply pipe 3 in this embodiment. The methane detector 301 can detect the gas content of the flue gas transported by the flue gas circulation pipe 7 and output a gas content signal. A quick-shutdown valve 703 is installed on the flue gas circulation pipe 7. The control device 8 is connected to the quick-shutdown valve 703 and the methane detector 301. Based on the received gas content signal, it determines the current gas content of the flue gas. If the current gas content is greater than a set content, such as 0.01%, it controls the quick-shutdown valve 703 to close.

[0036] The low-concentration gas combustion device provided by the present invention can control the mixing concentration of gas and auxiliary gas, ensure gas combustion efficiency, improve gas utilization, reduce gas content in flue gas, reduce resource waste, and avoid air pollution.

[0037] Furthermore, the flue gas recirculation pipe 7 also includes a shut-off valve 704, used to open or close the flue gas recirculation pipe 7.

[0038] Furthermore, the flue gas recirculation pipe 7 also includes: an oxygen content detection instrument 705, used to detect the oxygen content of the flue gas transported by the flue gas recirculation pipe 7 and generate an oxygen content signal; the control device 8 is connected to the oxygen content detection instrument 705 and is used to control the opening degree of the circulating flue gas flow valve 702 according to the received oxygen content signal, so as to control the oxygen content of the flue gas transported by the flue gas recirculation pipe 7 within a set range.

[0039] Specifically, in this embodiment of the invention, it is necessary to ensure a minimum oxygen content in the circulating flue gas, for example, a minimum oxygen content of 8%. An oxygen content detection instrument 705 is installed on the flue gas circulation pipe 7. The oxygen content detection instrument 705 can detect the oxygen content of the flue gas transported by the flue gas circulation pipe 7 and generate an oxygen content signal. The control device 8 is connected to the oxygen concentration detection instrument 705. If the oxygen content in the circulating flue gas is lower than the minimum oxygen content, the opening degree of the circulating flue gas flow valve 702 is increased.

[0040] Furthermore, the oxidation combustion device 4 also includes a heat storage chamber 406 for storing the heat energy generated during the combustion of the mixed combustion gas in the oxidation combustion chamber 401.

[0041] Furthermore, the low-concentration gas transmission pipe 1 also includes a gas concentration detection instrument 101, used to detect the content of gas input into the low-concentration gas transmission pipe 1.

[0042] Specifically, in this embodiment of the invention, a gas concentration detection instrument 101 is installed on the low-concentration gas transmission pipe 1. The gas concentration detection instrument 101 can detect the content of gas input into the low-concentration gas transmission pipe 1, facilitating real-time monitoring of the gas concentration. A gas flow meter 201 is also installed on the low-concentration gas transmission pipe 1 to monitor the gas flow rate.

[0043] Furthermore, the flue gas conveying pipe 3 also includes a flue gas flow meter 302, used to detect the flow rate of the flue gas conveyed by the flue gas conveying pipe 3.

[0044] Furthermore, an auxiliary gas fan 201 is installed on the auxiliary gas supply pipe 2, which can reduce the system resistance of the auxiliary gas flowing in the auxiliary gas supply pipe 2; a flue gas fan 304 is installed between the flue gas diversion interface 303 and the exhaust stack 5, which can reduce the system resistance of the flue gas flowing in the flue gas supply pipe 3.

[0045] Furthermore, the circulating flue gas flow valve 702 and the air flow valve 602 are explosion-proof flow valves.

[0046] Specifically, the valves and fans in the embodiments of the present invention, such as the circulating flue gas flow valve 702, the air flow valve 602, the quick shut-off valve 703, the shut-off valve 704, and the air distribution valve 405, are all explosion-proof valves, and the flue gas fan 304 and the auxiliary gas fan 201 are explosion-proof fans, so as to improve the safety of the low-concentration gas combustion device.

[0047] A second aspect of the present invention provides a low-concentration gas combustion system, including the low-concentration gas combustion device described above.

[0048] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0049] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0050] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A low-concentration gas combustion device, characterized in that, The low-concentration gas combustion device includes: Low-concentration methane gas pipeline, used for introducing low-concentration methane; Auxiliary gas supply pipe, used to input auxiliary gas; Flue gas delivery pipe, used to output flue gas; An oxidation combustion device includes an oxidation combustion chamber; the oxidation combustion chamber has a gas inlet, an auxiliary gas inlet, and a flue gas outlet, the gas inlet being connected to a low-concentration gas supply pipe, the auxiliary gas inlet being connected to an auxiliary gas supply pipe, and the flue gas outlet being connected to a flue gas supply pipe; the oxidation combustion chamber is used to mix the input low-concentration gas with the auxiliary gas to form a mixed combustion gas, and to output the flue gas generated by the combustion of the mixed combustion gas to the flue gas supply pipe through the flue gas outlet. An exhaust stack is installed at the outlet of the flue gas conveying pipe to discharge flue gas; An air supply pipe, connected to the auxiliary air supply pipe, is used to supply air to the auxiliary air supply pipe. An air flow meter and an air flow valve are installed on the air supply pipe. The air flow meter is used to detect the air flow rate of the air supply pipe and generate an air flow signal. The air flow valve is used to adjust the air flow rate of the air supply pipe. A flue gas recirculation pipe is disposed between the flue gas supply pipe and the auxiliary supply pipe. It is used to input a portion of the flue gas output from the flue gas supply pipe into the auxiliary supply pipe, and to input the auxiliary gas formed by the mixture of air and flue gas into the oxidation combustion chamber through the auxiliary supply pipe. The flue gas recirculation pipe is equipped with a recirculating flue gas flow meter and a recirculating flue gas flow valve. The recirculating flue gas flow meter is used to detect the flue gas flow rate of the flue gas recirculation pipe and generate a flue gas flow rate signal. The recirculating flue gas flow valve is used to adjust the flue gas flow rate of the flue gas recirculation pipe. The flue gas transmission pipe also includes: a methane detection instrument, used to detect the methane content of the flue gas transported by the flue gas circulation pipe and output a methane content signal to prevent excessive methane content from circulating back to the oxidation combustion chamber due to incomplete combustion; the flue gas circulation pipe also includes: a quick shut-off valve. The flue gas recirculation pipe also includes: an oxygen content detection instrument, used to detect the oxygen content of the flue gas transported by the flue gas recirculation pipe and generate an oxygen content signal; A control device, connected to the air flow meter, the air flow valve, the circulating flue gas flow meter and the circulating flue gas flow valve, the methane detector, the quick-shut-off valve, and the oxygen content detector, is used to control the opening degree of the circulating flue gas flow valve and the air flow valve according to the received air flow signal and flue gas flow signal, so as to adjust the ratio of flue gas flow to air flow within a set ratio range; determine the current gas content of the flue gas according to the received gas content signal, and control the quick-shut-off valve to close when the current gas content is greater than a set content; control the opening degree of the circulating flue gas flow valve according to the received oxygen content signal, so as to control the oxygen content of the flue gas transported by the flue gas circulation pipe within a set content range, the set content range including a minimum oxygen content, and when the oxygen content in the circulating flue gas is lower than the minimum oxygen content, the control device increases the opening degree of the circulating flue gas flow valve.

2. The low-concentration gas combustion device according to claim 1, characterized in that, The oxidation combustion chamber further includes an air distribution valve, on which the gas inlet, auxiliary gas inlet, and flue gas outlet are integrated.

3. The low-concentration gas combustion device according to claim 1, characterized in that, The flue gas recirculation pipe further includes a shut-off valve for opening or closing the flue gas recirculation pipe.

4. The low-concentration gas combustion device according to claim 1, characterized in that, The oxidation combustion device further includes a heat storage chamber for storing the heat energy generated during the combustion of the mixed combustion gases inside the oxidation combustion chamber.

5. The low-concentration gas combustion device according to claim 1, characterized in that, The low-concentration gas pipeline also includes a gas concentration detection instrument for detecting the content of gas input into the low-concentration gas pipeline.

6. The low-concentration gas combustion device according to claim 1, characterized in that, The flue gas conveying pipe also includes a flue gas flow meter, used to detect the flow rate of the flue gas conveyed by the flue gas conveying pipe.

7. The low-concentration gas combustion device according to claim 1, characterized in that, The circulating flue gas flow valve and the air flow valve are explosion-proof flow valves.

8. A low-concentration gas combustion system, characterized in that, The low-concentration gas combustion device includes any one of claims 1 to 7.

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