Low-concentration gas safe combustion device and method

Abstract

The invention discloses a low-concentration gas safe combustion device and method, and relates to the technical field of coal mine gas efficient governance, the low-concentration gas safe combustion device comprises a safety control unit, a gas pretreatment unit, a tempering and detonation prevention device, a combustor unit, a heat utilization unit, an efficiency detection unit and a flue gas purification unit, the gas pretreatment unit, the backfire and detonation prevention device, the burner unit, the heat utilization unit and the efficiency detection unit are in communication connection with the safety control unit, and the safety control unit is used for monitoring the pressure, temperature, gas concentration, gas flow, burner power and efficiency of the safety burning device in real time. The gas pretreatment unit can effectively achieve safe and stable combustion of low-concentration gas, the efficiency detection unit can monitor and optimize the combustion efficiency in real time, meanwhile, reliable anti-backfire and anti-deflagration measures are taken, the energy utilization rate is increased, and environmental pollution is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of efficient treatment of coal mine gas, and particularly to a low-concentration gas safe combustion device and method. Background Art

[0002] In order to reasonably solve the mine safety problem, the method of gas drainage is usually adopted to reasonably reduce the air-drained gas to a safe concentration below 1%. However, in the process of coal mine gas drainage in China, due to the single form of gas drainage, more air is mixed in, and the drainage volume fluctuates, resulting in most of the drained gas being low-concentration gas with a concentration below 30%. Among them, the drained gas with a concentration below 8% accounts for more than 70% of the total drainage volume. This part of the gas is in the explosion concentration range, and it is difficult to stably burn and efficiently utilize it by conventional combustion methods, so it is discharged into the atmospheric environment.

[0003] The main component of gas is methane, whose greenhouse effect is equivalent to 24.6 times that of CO2, and its ability to damage the atmospheric ozone layer is equivalent to 7 times that of CO2. Every year, a large amount of low-concentration gas gushes out and cannot be utilized, which not only causes serious waste of limited non-renewable resources, but also exacerbates air pollution and the greenhouse effect. Gas, as a high-quality energy source, has a calorific value of about 35000kJ / Nm 3 , which is equivalent to conventional natural gas and can be used as fuel and chemical raw materials, etc. Since oxygen is a combustible auxiliary agent, the introduction of oxygen increases the explosion risk of coalbed methane, bringing great difficulties to the processing and transportation of coalbed methane. At present, the categories, proportions, utilization rates and main utilization methods of drained coalbed methane. Among them, medium and high-concentration gas (C CH4 >30%) accounts for about 6%, and the utilization rate exceeds 90%. Low-concentration gas accounts for about 94%, but the utilization rate is lower than 35%. Due to the too low gas concentration in low-concentration gas, it is difficult to utilize. Its main utilization methods are regenerative oxidation and high-concentration gas blending combustion power generation, and the utilization efficiency of these methods is also relatively low. As a result, most of the low-concentration gas is directly discharged into the atmosphere, causing huge resource waste. At the same time, the environment has also been greatly damaged. A large amount of low-concentration gas with a concentration below 8% is difficult to be directly utilized and is discharged into the atmospheric environment, causing great waste of energy and serious environmental pollution.

[0004] Therefore, it is necessary to develop and design a low-concentration gas safe combustion device and method to effectively achieve the safe and stable combustion of low-concentration gas, and be able to monitor and optimize the combustion efficiency in real time. At the same time, it has reliable anti-backfire and deflagration measures. Improving the energy utilization rate and reducing environmental pollution are the technical problems that need to be solved urgently by those skilled in the art at present. Summary of the Invention

[0005] To solve the above problems, the present invention provides a low-concentration gas safety combustion device and method, which can effectively achieve the safe and stable combustion of low-concentration gas, can monitor and optimize the combustion efficiency in real time, and at the same time has reliable anti-backfire and deflagration prevention measures, improve energy utilization rate, and reduce environmental pollution.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A low-concentration gas safety combustion device includes a safety control unit, a gas pretreatment unit, an anti-backfire and deflagration device, a burner unit, a heat utilization unit, an efficiency detection unit, and a flue gas purification unit that are connected in sequence. The gas pretreatment unit, the anti-backfire and deflagration device, the burner unit, the heat utilization unit, and the efficiency detection unit are communicatively connected to the safety control unit. The safety control unit is used to monitor the pressure, temperature, gas concentration, gas flow rate, burner power, and efficiency of the safety combustion device in real time.

[0008] Preferably, the gas pretreatment unit includes a dust removal unit, a cyclone dehumidification unit, and a pressure stabilization unit that are connected in sequence.

[0009] Preferably, the dust removal unit includes a dust removal bin, a low-concentration gas inlet provided on the dust removal bin, a spray device and a porous bed layer sequentially provided inside the dust removal bin, a spray water outlet communicated with a sedimentation tank, and a first gas outlet provided on the dust removal bin away from the low-concentration gas inlet;

[0010] The cyclone dehumidification unit includes a cyclone separator, a first gas inlet provided on the cyclone separator and communicated with the first gas outlet, a second gas outlet provided on the cyclone separator, and a dehumidified water outlet communicated with the sedimentation tank;

[0011] The pressure stabilization unit includes a pressure stabilization bin, a second gas inlet provided on the pressure stabilization bin and communicated with the second gas outlet, a third gas outlet, and a throttling device provided inside the pressure stabilization bin. An inlet of a pressure stabilization branch is provided on the pressure stabilization bin between the throttling device and the third gas outlet. The outlet of the pressure stabilization branch is provided between the second gas inlet and the throttling device. A first pressure regulating valve, a pressure regulating bin, and a second pressure regulating valve are sequentially provided on the pressure stabilization branch.

[0012] Preferably, the burner unit includes a burner body. A gas inlet channel, a gas inlet device, a flame stabilization device, an automatic ignition device, a flame monitoring device, a temperature monitoring device, and a burner outlet that are communicated with the third gas outlet are sequentially provided on the burner body. An air inlet is also provided on the burner body.

[0013] Preferably, the gas inlet passage is spiral or porous, and a flow guide plate is arranged on the inner wall of the burner. The flow guide plate near the gas inlet passage extends towards the gas inlet passage, and the flow guide plate near the burner outlet extends towards the burner outlet.

[0014] Preferably, the efficiency detection unit includes a temperature detection device, a methane detection device, a carbon monoxide detection device, a carbon dioxide detection device, and an oxygen detection device installed at the burner outlet.

[0015] Preferably, the anti-backfire and deflagration safety device includes a flashback arrester installed on the gas inlet passage, a cut-off valve arranged on the gas inlet passage, and a pressure sensor, a temperature sensor, and a flame sensor installed on the gas inlet passage.

[0016] Preferably, the flashback arrester is a water-sealed arrester or a dry flashback arrester.

[0017] The present invention also discloses a method for safe combustion of low-concentration gas, which applies the low-concentration gas safe combustion device as described above, and is characterized by including the following steps:

[0018] The low-concentration gas enters the gas pretreatment unit for dust removal, dehumidification, and pressure stabilization treatment;

[0019] The pretreated gas and air enter the burner unit, the gas and air are mixed and ignited inside the burner, and the flame state is monitored in real time;

[0020] The burned gas flue gas is reused through the heat utilization unit;

[0021] The efficiency detection unit monitors the gas combustion efficiency in real time, transmits relevant data to the safety control unit, and at the same time the anti-backfire and deflagration device monitors the combustion state in real time;

[0022] The flue gas is discharged after being purified by the flue gas purification unit.

[0023] Preferably, when the combustion efficiency is lower than the preset value, the safety control unit controls the gas and air intake ratio and the flame height in the burner to make the combustion efficiency reach the preset value;

[0024] When the anti-backfire and deflagration device monitors that the gas concentration is between 3 and 8, the gas intake stops, and the burner is purged. When the efficiency detection unit monitors that there is no methane in the gas tail gas, gas is continuously introduced into the burner unit and ignited.

[0025] The present invention has achieved the following technical effects compared with the prior art:

[0026] It can be automatically adjusted and alarmed according to the preset safety threshold. When abnormal situations occur, it can quickly cut off the gas supply, and organically integrate the gas pretreatment unit, anti-backfire and deflagration device, burner unit, heat utilization unit, efficiency detection unit, flue gas purification unit and safety control unit. The gas pretreatment unit can effectively achieve the safe and stable combustion of low-concentration gas. The efficiency detection unit can monitor and optimize the combustion efficiency in real time, and at the same time has reliable anti-backfire and deflagration measures, improving the energy utilization rate and reducing environmental pollution. Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Attached Figure 1 It is a schematic diagram of the overall structure of the low-concentration gas safe combustion device disclosed by the present invention;

[0029] Attached Figure 2 It is a schematic diagram of the overall structure of the gas pretreatment unit of the low-concentration gas safe combustion device disclosed by the present invention;

[0030] Attached Figure 3 It is a schematic diagram of the overall structure of the burner unit of the low-concentration gas safe combustion device disclosed by the present invention;

[0031] Attached Figure 4 It is a schematic diagram of the overall structure of the efficiency detection unit of the low-concentration gas safe combustion device disclosed by the present invention;

[0032] Among them, 1. Safety control unit; 2. Gas pre-treatment unit; 3. Backfire and deflagration prevention device; 4. Burner unit; 5. Heat utilization unit; 6. Efficiency detection unit; 7. Flue gas purification unit; 8. Dust removal bin; 9. Low-concentration gas inlet; 10. Spraying device; 11. Porous bed layer; 12. First gas outlet; 13. Sedimentation tank; 14. Cyclone separator; 15. First gas inlet; 16. Second gas outlet; 17. Dehumidified water outlet; 18. Pressure stabilizing bin; 19. Second gas inlet; 20. Third gas outlet; 21. Throttling device; 22. First pressure regulating valve; 23. Second pressure regulating valve; 24. Pressure regulating bin; 25. Burner body; 26. Third gas inlet; 27. Gas inlet channel; 28. Gas inlet device; 29. Flame stabilizing device; 30. Automatic ignition device; 31. Flame monitoring device; 32. Temperature monitoring device; 33. Burner outlet; 34. Deflector; 35. Temperature detection device; 36. Methane detection device; 37. Carbon monoxide detection device; 38. Carbon dioxide detection device; 39. Oxygen detection device. Detailed implementation manners

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] The purpose of the present invention is to provide a low-concentration gas safety combustion device and method, which can effectively achieve the safe and stable combustion of low-concentration gas, can monitor and optimize the combustion efficiency in real time, and at the same time has reliable backfire and deflagration prevention measures, improves the energy utilization rate, and reduces environmental pollution.

[0035] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0036] Refer to Figure 1, the low-concentration gas safety combustion device disclosed in the embodiments of the present invention at least includes a safety control unit 1, a gas pretreatment unit 2, an anti-backfire and deflagration device 3, a burner unit 4, a heat utilization unit 5, an efficiency detection unit 6, and a flue gas purification unit 7 that are connected in sequence. The gas pretreatment unit 2, the anti-backfire and deflagration device 3, the burner unit 4, the heat utilization unit 5, and the efficiency detection unit 6 are communicatively connected to the safety control unit 1. The safety control unit 1 is used to monitor the pressure, temperature, gas concentration, gas flow rate, combustion power, and efficiency in the entire safety combustion device in real time, and can automatically adjust and alarm according to preset safety thresholds. When abnormal conditions occur, it can quickly cut off the gas supply, integrating the gas pretreatment unit 2, the anti-backfire and deflagration device 3, the burner unit 4, the heat utilization unit 5, the efficiency detection unit 6, the flue gas purification unit 7, and the safety control unit 1 organically. The gas pretreatment unit 2 can effectively achieve the safe and stable combustion of low-concentration gas. The efficiency detection unit 6 can monitor and optimize the combustion efficiency in real time, and at the same time has reliable anti-backfire and deflagration measures, improving the energy utilization rate and reducing environmental pollution.

[0037] Reference Figure 2 , in one embodiment, the gas pretreatment unit 2 includes a dust removal unit, a cyclone dehumidification unit, and a pressure stabilizing unit that are connected in sequence, which can ensure the stable quality of the gas entering the burner unit 4.

[0038] Reference Figure 2 , as a preferred method, the dust removal unit includes a dust removal bin 8. A low-concentration gas inlet 9 is provided on the dust removal bin 8. A spraying device 10 and a porous bed layer 11 are sequentially arranged inside the dust removal bin 8. A spraying water outlet communicating with a sedimentation tank 13 is also provided on the dust removal bin 8. A first gas outlet 12 is provided at one end of the dust removal bin 8 away from the low-concentration gas inlet 9. Through the setting of the dust removal unit, gas enters the dust removal unit from the low-concentration gas inlet 9, is atomized and sprayed, and then enters the porous bed layer 11 for filtration to purify the gas.

[0039] The cyclone dehumidification unit includes a cyclone separator 14, a first gas inlet 15 provided on the cyclone separator 14 and communicating with the first gas outlet 12, a second gas outlet 16 provided on the cyclone separator 14, and a dehumidified water outlet 17 provided on the cyclone separator 14 and communicating with the sedimentation tank 13;

[0040] It should be noted that a humidity sensor is also provided at the second gas outlet 16, and a circulation pipeline communicating with the first gas inlet 15 is provided at the second gas outlet 16. The purified gas enters the cyclone separator 14 for dehumidification. After dehumidification, the gas is detected for its humidity by the humidity sensor provided at the second gas outlet 16, and the data is fed back to the safety control unit 1. After meeting the intake requirements of the combustion unit, it enters the next unit through the pressure stabilizing device. If the intake requirements are not met, it enters the first gas inlet 15 through the circulation pipeline for secondary dehumidification until the requirements are met. The water after spraying and the water separated by dehumidification enter the sedimentation tank 13 together. After sedimentation and separation, it is pumped to the atomization of the dust removal unit for dust removal of the gas. The water separated by the dehumidification unit can be directly sent to the dust removal unit to spray the gas.

[0041] The pressure stabilizing unit includes a pressure stabilizing chamber 18. A second gas inlet 19 communicating with the second gas outlet 16 is provided on the pressure stabilizing chamber 18. A third gas outlet 20 is provided on the pressure stabilizing chamber 18. A throttling device 21 is arranged inside the pressure stabilizing chamber 18. A pressure stabilizing branch is provided on the pressure stabilizing chamber 18 between the throttling device 21 and the third gas outlet 20. The outlet of the pressure stabilizing branch is arranged between the second gas inlet 19 and the throttling device 21. A first pressure regulating valve 22 and a second pressure regulating valve 23 are successively arranged on the pressure stabilizing branch. A plurality of pressure regulating chambers 24 are arranged between the first pressure regulating valve 22 and the second pressure regulating valve 23. Pressure sensors are provided at both the second gas inlet 19 and the third gas outlet 20.

[0042] The pressure stabilizing unit ensures that the gas is in the range of 2 kPa to 10 kPa. When the sensor at the second gas inlet 19 detects that the gas pressure exceeds 10 kPa, a signal is transmitted to the safety control unit 1. The safety control unit 1 controls the first pressure regulating valve 22 and the second pressure regulating valve 23 to open automatically. The gas enters the pressure stabilizing chamber 18 from the second pressure regulating valve 23 for pressure stabilization to reduce the pressure value. Then, the gas pressure value at the third gas outlet 20 is monitored by the pressure sensor provided at the third gas outlet 20 to see if it meets the requirements. If it does not meet the requirements, the third gas outlet 20 is closed through the safety control unit 1. If it meets the requirements, it is transported to the next unit. When the sensor at the second gas inlet 19 detects that the gas pressure is lower than 2 kPa, the throttling device 21 is adjusted through the safety control unit 1 to increase the intake pressure.

[0043] Reference Figure 3, as an implementation, the burner unit 4 includes a burner body 25. A gas inlet passage 27 communicating with the third gas inlet 26, a gas inlet device 28, a flame stabilization device 29, an automatic ignition device 30, a flame monitoring device 31, a temperature monitoring device 32, and a burner outlet 33 are sequentially arranged on the burner body 25. An air inlet is also arranged on the burner body 25. Inside the burner unit 4, gas and air can be mixed, and the automatic ignition device 30 is controlled by the safety control unit 1 to perform ignition, realizing the combustion of the gas. The shape of the flame is monitored through the flame monitoring device 31. If the flame is unstable, the intake ratio of gas and air is adjusted to dynamically mix the gas and air and form a stable flame shape, preventing flashback and blowout phenomena. The temperature inside the burner is monitored in real time through the temperature monitoring device 32.

[0044] Reference Figure 3 , as a preferred way, the gas inlet passage 27 is spiral or porous. A deflector 34 is arranged on the inner wall of the burner. The deflector 34 near the gas inlet passage 27 extends towards the gas inlet passage 27, and the deflector 34 near the burner outlet 33 extends towards the burner outlet 33. The spiral gas inlet passage 27 forms a swirling flow field through the action of centrifugal force, extending the mixing path of gas and air and ensuring uniform mixing. The porous gas inlet passage 27 increases micro-scale turbulence, increases the contact area between gas and oxygen, and improves the combustion reaction rate. The extending direction of the deflector 34 near the gas inlet passage 27 is the same as the direction of the spiral gas flow, which can maintain the swirling intensity and avoid too rapid energy decay. The deflector 34 near the burner outlet 33 extending towards the burner outlet 33 can guide the high-temperature flue gas to be discharged quickly, reducing the retention of unburned gas.

[0045] Reference Figure 4 , as a preferred way, the efficiency detection unit 6 includes a temperature detection device 35, a methane detection device 36, a carbon monoxide detection device 37, a carbon dioxide detection device 38, and an oxygen detection device 39 installed at the burner outlet 33. The temperature, methane content, carbon monoxide, carbon dioxide, and oxygen data detected by the efficiency detection unit 6 are transmitted to the safety control unit 1. By detecting the unburned gas components and oxygen content parameters at the burner outlet 33, combining the intake gas volume and air volume, the combustion efficiency of the gas is calculated using a specific algorithm, and the data is transmitted to the controller for further optimization and adjustment of the combustion process;

[0046] It should be noted that the efficiency calculation method is as follows:

[0047] CH4 + 3O2 = 4CO + 2H2O

[0048] CH4 ——> CH4

[0049] According to the amount of methane equivalent converted from the carbon monoxide content in the flue gas after combustion over a period of time, plus the residual amount of unburned methane in the flue gas, the total amount of methane Vt in the flue gas is obtained. By detecting the total volume V0 of methane in the gas before combustion, and then through the formula (V0 - Vt) / V0 = efficiency, the combustion efficiency is obtained.

[0050] Reference Figure 1 As an implementation method, the backfire and deflagration prevention device 3 includes a flashback arrester installed on the gas inlet channel 27, a cut-off valve provided on the gas inlet channel 27, and a pressure sensor, a temperature sensor, and a flame sensor installed on the gas inlet channel 27. Once the pressure sensor detects a sudden increase in pressure, the pressure is greater than 10 kPa, or the flame sensor monitors abnormal fluctuations in the flame, and the temperature sensor monitors an increase in temperature and the temperature is greater than 180°C. For these signs of backfire or deflagration, the safety control unit 1 immediately controls the quick cut-off valve to close and initiates emergency measures, such as turning on the air purge device provided in the burner body 25 to reduce the gas concentration in the combustion area and prevent deflagration from occurring.

[0051] Reference Figure 4 As an implementation method, the flashback arrester is a water-sealed arrester or a dry flashback arrester.

[0052] The present invention also discloses a method for safe combustion of low-concentration gas, which is applied as described in any one of the above, and includes the following steps:

[0053] The low-concentration gas enters the gas pretreatment unit 2 for dust removal, dehumidification, and pressure stabilization treatment;

[0054] The pretreated gas and air enter the burner unit 4, the gas and air are mixed and ignited inside the burner, and the flame state is monitored in real time through the flame monitoring device 31;

[0055] The combusted gas flue gas is reused through the heat utilization unit 5;

[0056] The efficiency detection unit 6 monitors the gas combustion efficiency in real time and transmits relevant data to the safety control unit 1. When the combustion efficiency is lower than the preset value, the safety control unit 1 controls the gas and air intake ratio and the flame height in the burner to make the combustion efficiency reach the preset value;

[0057] At the same time, the backfire and deflagration prevention device 3 monitors the combustion state in real time. When the backfire and deflagration prevention device 3 monitors that the gas concentration is greater than 9% for a long time (longer than 5 minutes), the gas intake stops, and the burner body 25 is purged through the air purge device in the burner body 25. When the efficiency detection unit 6 monitors that there is no methane in the gas tail gas, the gas is continuously introduced into the burner unit 4 and ignited;

[0058] The flue gas is discharged after being purified by the flue gas purification unit 7.

[0059] In this embodiment, the gas pretreatment unit 2, the anti-backfire and deflagration device 3, the burner unit 4, the heat utilization unit 5, the efficiency detection unit 6, the flue gas purification unit 7 and the safety control unit 1 are organically integrated. The gas pretreatment unit 2 lays a foundation for subsequent stable combustion through dust removal, dehumidification and pressure stabilization, ensuring the reliable quality of the gas entering the system and reducing unstable factors from the source; the unique intake air and combustion chamber design of the burner unit 4 realizes the dynamic mixing of gas and air and the formation of a stable flame, overcoming the problems of easy backfire and flashback in traditional combustion. Each unit operates in coordination to solve various problems faced by low-concentration gas combustion in one stop. Compared with decentralized treatment or single-function equipment, the integrity and reliability of the system are greatly improved;

[0060] Precise combustion efficiency monitoring and regulation: The combustion efficiency detection unit 6 real-time detects key parameters such as the composition of unburned gas and the oxygen content, combines the intake air data, calculates the combustion efficiency by means of a specific algorithm, and transmits it to the safety control unit 1. The safety control unit 1 automatically optimizes the combustion process based on this information, such as precisely adjusting the intake ratio of gas and air and the flame intensity, breaking the limitation of traditional combustion adjustment based solely on experience or rough estimation, realizing intelligent and refined combustion management, and ensuring efficient energy utilization;

[0061] Reliable anti-backfire and deflagration protection system: The anti-backfire and deflagration device 3 adopts a water-sealed or dry structure, which can effectively cut off the backfire path and prevent the spread of backfire to the gas source, ensuring safety from the transmission link; the electromagnetic fast cut-off valve has a response speed of milliseconds. It immediately cuts off the gas supply when signs of backfire or deflagration are detected, and cooperates with the safety control unit 1 to increase the air purge volume and other emergency operations to quickly dilute the gas concentration in the combustion area. Multiple measures are taken to nip the risks of backfire and deflagration in the bud, greatly improving the safety of the combustion system and filling the shortcoming of the safety protection of traditional low-concentration gas combustion.

[0062] It should be noted that for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

Claims

1. A low-concentration gas safe combustion device, characterized in that: It includes a safety control unit, a gas pretreatment unit, a backfire and deflagration prevention device, a burner unit, a heat utilization unit, an efficiency detection unit and a flue gas purification unit which are connected in sequence. The gas pretreatment unit, the backfire and deflagration prevention device, the burner unit, the heat utilization unit and the efficiency detection unit are communicatively connected with the safety control unit. The safety control unit is used for real-time monitoring of the pressure, temperature, gas concentration, gas flow, burner power and efficiency of the safety combustion device.

2. The low-concentration gas safe combustion device according to claim 1, characterized in that: The gas pretreatment unit comprises a dust removal unit, a cyclone dehumidification unit and a pressure stabilization unit which are connected in sequence.

3. The low-concentration gas safe combustion device according to claim 2 is characterized in that: The dust removal unit includes a dust removal bin, a low-concentration gas inlet arranged on the dust removal bin, a spray device and a porous bed layer arranged in sequence inside the dust removal bin, a spray water outlet connected to the sedimentation tank, and a first gas outlet arranged in the dust removal bin away from the low-concentration gas inlet; The cyclone dehumidification unit includes a cyclone separator, a first gas inlet disposed on the cyclone separator and communicating with the first gas outlet, a second gas outlet disposed on the cyclone separator, and a dehumidified water outlet communicating with the settling tank; The pressure stabilizing unit includes a pressure stabilizing chamber, a second gas inlet and a third gas outlet arranged on the pressure stabilizing chamber and connected to the second gas outlet, and a throttling device arranged inside the pressure stabilizing chamber, an inlet of a pressure stabilizing branch is arranged on the pressure stabilizing chamber between the throttling device and the third gas outlet, and the outlet of the pressure stabilizing branch is arranged between the second gas inlet and the throttling device, and a first pressure regulating valve, a pressure regulating chamber and a second pressure regulating valve are arranged in sequence on the pressure stabilizing branch.

4. The low-concentration gas safe combustion device according to claim 3 is characterized in that: The burner unit includes a burner body, on which a gas inlet passage connected to the third gas outlet, a gas inlet device, a flame stabilization device, an automatic ignition device, a flame monitoring device, a temperature monitoring device and a burner outlet are sequentially arranged, and the burner body is also provided with an air inlet.

5. The low-concentration gas safe combustion device according to claim 4, characterized in that: The gas inlet passage is spiral or porous, and the inner wall of the burner is provided with a guide plate. The guide plate close to the gas inlet passage extends toward the gas inlet passage, and the guide plate close to the burner outlet extends toward the burner outlet.

6. The low-concentration gas safe combustion device according to claim 4, characterized in that: The efficiency detection unit includes a temperature detection device, a methane detection device, a carbon monoxide detection device, a carbon dioxide detection device and an oxygen detection device installed at the burner outlet.

7. The low-concentration gas safe combustion device according to claim 4, characterized in that: The anti-backfire and deflagration safety device comprises a backfire preventer installed on the gas inlet passage, a cut-off valve arranged on the gas inlet passage, and a pressure sensor, a temperature sensor and a flame sensor installed on the gas inlet passage.

8. The low-concentration gas safe combustion device according to claim 7, characterized in that: The flashback arrester is a water-sealed flashback arrester or a dry flashback arrester.

9. A low-concentration gas safe combustion method, using the low-concentration gas safe combustion device as described in any one of claims 1 to 8, characterized in that: The following steps are involved: Low-concentration gas enters the gas pretreatment unit for dust removal, dehumidification and pressure stabilization; The pre-treated gas and air enter the burner unit, the gas and air are mixed and ignited inside the burner, and the flame state is monitored in real time; The combusted gas and flue gas are recycled through the heat utilization unit; The efficiency detection unit monitors the gas combustion efficiency in real time and transmits relevant data to the safety control unit, while the anti-backfire and deflagration device monitors the combustion state in real time; The flue gas is discharged after being purified by the flue gas purification unit.

10. The low-concentration gas safe combustion method according to claim 9, characterized in that: When the combustion efficiency is lower than a preset value, the safety control unit controls the gas and air intake ratio and the flame height in the burner to make the combustion efficiency reach the preset value; When the anti-backfire and deflagration device detects that the gas concentration is between 3 and 8, the gas intake stops and the burner body is purged. When the efficiency detection unit detects that there is no methane in the gas tail gas, the gas continues to be introduced into the burner unit and ignited.

Images