A detachable low-concentration gas catalytic oxidation reactor suitable for multiple working conditions

Abstract

This invention discloses a detachable low-concentration methane catalytic oxidation reactor suitable for multiple operating conditions, comprising a reactor body, a reactor cover, a burner, a gas supply device, and a gas collection and detection device. The reactor body has a connecting base inside, and the burner is detachably connected to the connecting base. The reactor cover is detachably connected to the reactor body via a quick-opening mechanism. Depending on the operating conditions, a preheating burner, a high-gas-velocity burner, or a two-stage burner can be selected for installation within the reactor body. The preheating burner utilizes high-temperature flue gas for heat exchange and preheating of the gas mixture to be combusted; the high-gas-velocity burner improves gas distribution through an inner cylinder, an outer cylinder, and a radial flow distribution structure; the two-stage burner improves the conversion rate of combustible components through upper and lower catalytic reaction zones and high-temperature gas circulation. This reactor can adapt to different concentrations, flow rates, and thermal circulation requirements, facilitates rapid assembly and disassembly of the burner and catalyst, and improves the stability and detection convenience of low-concentration methane catalytic combustion.

Description

Technical Field

[0001] This invention relates to the field of catalytic oxidation technology, and more specifically to a low-concentration gas catalytic oxidation reactor that is detachable and suitable for multiple operating conditions. Background Technology

[0002] Catalytic oxidation technology, by loading catalytically active substances onto the surface of porous media, can effectively reduce the activation energy of fuel, enabling difficult-to-ignite gas mixtures to undergo chemical reactions at low temperatures. This is a surface heterogeneous reaction. This technology can significantly broaden the lean-burn limit of fuels, achieving stable processing under ultra-low equivalence ratio conditions. Furthermore, through kinetic control, the reaction temperature can be maintained at a low level, suppressing the generation of harmful gases such as nitrogen oxides at the source. It has significant application value in the treatment of ultra-low calorific value fuels such as low-concentration methane.

[0003] Currently, mainstream catalytic oxidation reactors are relatively simple in design, mostly adopting fixed structures or integrated encapsulation modes. They are poorly adaptable to complex and changing operating conditions, specifically manifested in the following ways:

[0004] 1. Cumbersome disassembly and maintenance, high cost and long cycle: Traditional reactors mostly adopt integrated packaging or bolt-fastened sealing, without convenient modular disassembly and assembly design. When the catalyst has problems such as high temperature sintering, carbon deposits, dust covering and other activity reduction problems, it is necessary to shut down for a long time to cool before large-scale disassembly and replacement. The maintenance cost is high and the cycle is long, which makes it difficult to meet the industrial demand for rapid performance recovery.

[0005] 2. Poor compatibility between flow field and thermal cycle, and easy flameout due to lean combustion: Most existing reactors are axial flow fixed layer structures with fixed internal heat transfer paths. The heat recirculation efficiency cannot be dynamically adjusted according to the fluctuation of fuel calorific value, which easily leads to unstable flame stationary position. Under lean combustion conditions, flameout or flameout is very likely to occur.

[0006] 3. High gas velocity conditions result in high resistance, which can easily induce instability and oscillation: For high gas velocity conditions, existing technologies often suppress oscillation and tempering by increasing the thickness of porous media or setting pore gradient stratification. However, axial flow will cause the fluid resistance (pressure drop) to increase exponentially, and a single flow channel layout is prone to causing local flow field instability and thermoacoustic oscillation. Summary of the Invention

[0007] The purpose of this invention is to provide a multi-condition catalytic oxidation reactor adapted to low-concentration methane, so as to overcome the defects of existing catalytic oxidation reactors, such as poor adaptability to operating conditions, unadjustable thermal cycle efficiency, large flow resistance at high gas velocities, and susceptibility to thermoacoustic vibration. It achieves modular and rapid disassembly and assembly, reduces catalyst replacement and maintenance costs, and meets the needs of rapid maintenance and efficient and stable operation in laboratory and industrial settings.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a low-concentration gas catalytic oxidation reactor suitable for multiple working conditions and detachable, comprising a reactor body, a reactor cover, a burner, a gas supply device, and a gas collection and detection device;

[0009] The reactor body has an internal cavity for accommodating the burner. A connecting base is provided at the bottom of the internal cavity. The burner is disposed in the internal cavity and is detachably connected to the connecting base so that the burner can be installed or removed through the upper opening of the internal cavity of the reactor body.

[0010] The reactor cover is located on the upper opening of the inner cavity of the reactor body and is detachably connected to the reactor body via a quick-opening mechanism.

[0011] The reactor cover is provided with a first flue gas outlet, an electrode igniter and a heat exchange coil sealing interface. The reactor body is provided with a gas inlet, a second flue gas outlet and multiple temperature sensor interfaces. Valves are provided at the first flue gas outlet, the second flue gas outlet, the gas inlet and the heat exchange coil sealing interface respectively.

[0012] The gas supply device is selectively connected to the gas inlet and / or the heat exchange coil sealing interface, and is used to supply combustion gas to the burner;

[0013] The gas collection and detection device is selectively connected to the first flue gas outlet and / or the second flue gas outlet, and is used to collect and detect the flue gas generated by the burner;

[0014] The burner is any one of a preheating burner, a high-gas-velocity burner, or a two-stage burner, and different types of burners can be selectively installed in the reactor body according to the operating conditions.

[0015] As a further improvement of the present invention, the quick-opening mechanism is a clamp assembly, which includes a clamp body, a screw locking handle, and a locking nut. The clamp body includes two identical semi-circular clamp strips, one end of which is hinged, and the other end is respectively connected to the screw locking handle and the locking nut. The screw locking handle is threadedly connected to the locking nut. The clamp strips are provided with a groove along their length. After the upper edge of the reactor cover and the upper edge of the reactor body are aligned, they are located in the groove and locked by the screw locking handle and the locking nut threadedly.

[0016] As a further improvement of the present invention, the gas supply device includes a fuel gas cylinder, an air cylinder, a mixing chamber, and a gas distribution box. The fuel gas cylinder and the air cylinder are both connected to the gas distribution box, the gas distribution box is connected to the mixing chamber, and the mixing chamber is connected to the gas inlet pipeline.

[0017] As a further improvement of the present invention, the preheating burner has a cylindrical structure, with its upper end open, forming a flue gas flow space between it and the reactor cover; the preheating burner is filled with a catalyst, and its outer wall is wound with a heat exchange coil, the inlet end of which is connected to a sealed interface, and the outlet end of which is connected to a preheating gas inlet located at the lower part of the side wall of the preheating burner; an inner flow channel is formed inside the preheating burner, and an outer flow channel is formed between the preheating burner and the reactor body, the inner flow channel and the outer flow channel being connected via the preheating burner... The upper opening of the burner is connected; the outer flow channel is connected to the second flue gas outlet, so that the high-temperature flue gas generated by the preheating burner enters the outer flow channel through its upper opening, and exchanges heat with the gas mixture to be combusted in the heat exchange coil when it flows through the heat exchange coil, and then is discharged through the second flue gas outlet; the two side walls of the reactor body are respectively provided with multiple temperature sensor interfaces arranged at intervals in the vertical direction, one side of which is used to install a thermocouple to measure the temperature of the inner flow channel, and the other side of which is used to install a thermocouple to measure the temperature of the outer flow channel.

[0018] As a further improvement of the present invention, the burner cylinder wall is provided with an inner insulation layer, and the reactor main cylinder wall is provided with an outer insulation layer.

[0019] As a further improvement of the present invention, the high-gas-velocity burner includes an inner cylinder and an outer cylinder arranged coaxially. An annular catalytic reaction zone is formed between the inner cylinder and the outer cylinder, and a catalyst is filled in the annular catalytic reaction zone. The lower end of the inner cylinder is detachably connected to the connecting base and communicates with the gas inlet. The inner cylinder wall is provided with a plurality of first vent holes at intervals along the circumference and axial direction, so that the mixed gas entering the inner cylinder from the gas inlet is dispersed through the plurality of first vent holes and enters the annular catalytic reaction zone radially. The outer cylinder is arranged around the outside of the inner cylinder. The outer cylinder wall is provided with a plurality of second vent holes, so that the flue gas after catalytic reaction in the annular catalytic reaction zone is discharged through the plurality of second vent holes to the flue gas flow channel between the outer cylinder and the reactor body, and discharged through the first flue gas outlet. The top of the inner cylinder is closed or sealed with the reactor cover to restrict the mixed gas from flowing out directly along the axial direction of the inner cylinder, so that the mixed gas entering the inner cylinder flows radially into the annular catalytic reaction zone through the first vent holes.

[0020] As a further improvement of the present invention, the two-stage burner includes an upper burner and a lower burner. The bottom of the lower burner is detachably connected to the connecting base, and the upper part of the lower burner is detachably connected to the upper burner. The upper and lower burners are respectively filled with different types of porous catalytic media. One side of the reactor body is provided with multiple temperature sensor interfaces, and thermocouples are inserted into the upper and lower burners through the temperature sensor interfaces to measure the combustion temperature in the two burners. The other side of the reactor body is provided with a suction pump, which is connected to the outlet of the upper burner through an inflow pipe and to the space between the upper and lower burners through an outflow pipe, so as to draw a portion of the high-temperature flue gas at the outlet of the upper burner back to the space between the upper and lower burners. The gas inlet is connected to the lower burner, and the first flue gas outlet is connected to the outlet side of the upper burner.

[0021] As a further improvement of the present invention, it also includes a reactor platform, wherein the reactor body is disposed on the reactor platform.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. This invention incorporates a connecting base within the reactor body, allowing for a detachable connection between the burner and the base. This enables the reactor body to be equipped with a preheating burner, a high-gas-velocity burner, or a two-stage burner, depending on the concentration, calorific value, inlet gas velocity, and combustion test requirements of the low-concentration gas. Different types of burners share the same reactor body, gas supply device, ignition device, temperature detection device, and gas collection and detection device, eliminating the need for separate reactor configurations for different operating conditions. This improves the equipment's versatility and adaptability to various operating conditions, while reducing equipment configuration costs.

[0024] 2. The reactor cover and reactor body of the present invention are detachably connected via a quick-opening mechanism, and the bottom of the burner is detachably connected to the connecting base. When it is necessary to replace the burner or catalyst, the reactor cover can be opened, and the burner can be directly removed from the upper opening of the inner cavity of the reactor body. There is no need to disassemble the reactor body and its surrounding gas supply and detection equipment as a whole, thereby simplifying the disassembly and assembly steps, shortening downtime for maintenance, and reducing the cost of catalyst replacement and equipment maintenance.

[0025] 3. The preheating burner, through the installation of heat exchange coils, inner and outer flow channels, allows the high-temperature flue gas generated during combustion to enter the outer flow channel from the top of the burner and exchange heat with the unburned mixture in the heat exchange coils. The preheated mixture then enters the burner to participate in the reaction, thereby recovering and utilizing the waste heat of the flue gas and increasing the temperature of the mixture entering the catalyst zone. Combined with the insulation structures on the burner and reactor walls, heat loss is reduced, improving the ignition and self-sustaining combustion conditions for low-concentration, low-calorific-value gases, and reducing the risk of flameout or unstable combustion under lean-burn conditions.

[0026] 4. The high-gas-velocity burner is equipped with a porous inner cylinder and a porous outer cylinder that work together, forming a catalyst zone between the inner and outer cylinders. High-speed mixed gas entering from the bottom of the reactor first enters the inner cylinder, and then disperses into the catalyst zone through the circumferential and height-direction holes in the inner cylinder, transforming the concentrated axial flow of the gas into a radially dispersed flow. This structure increases the effective flow area, improves the uniformity of gas distribution within the catalyst zone, reduces local airflow velocity and local pressure drop, lowers the risk of local flow field instability, backfire, and thermoacoustic oscillation caused by concentrated high-speed airflow, and improves combustion stability under high-gas-velocity conditions.

[0027] 5. The two-stage burner consists of a detachably connected upper burner and a lower burner, each containing porous catalytic media with different properties. Low-concentration methane entering the reactor undergoes primary oxidation in the lower burner before entering the upper burner, where a more catalytically active medium further oxidizes the remaining combustible components. By segmenting the catalytic reaction zones, appropriate catalytic media can be selected for different reaction stages, improving the overall conversion rate of combustible components and reducing the content of residual combustible components in the exhaust gas while balancing catalyst cost and high-temperature resistance.

[0028] 6. This invention includes an external extraction pump for the two-stage burner. The extraction pump is connected to the outlet of the upper burner via an inflow pipe and to the space between the upper and lower burners via an outflow pipe. The extraction pump extracts a portion of the high-temperature gas from the outlet of the upper burner and reintroduces it into the space between the two burners. The residual heat of the high-temperature gas increases the temperature of the gas entering the upper burner, enhancing heat transfer between the two burners and promoting further oxidation of residual combustible components. By adjusting the extraction rate of the extraction pump, the flow rate and thermal cycle intensity of the circulating high-temperature gas can also be adjusted, thereby improving the adaptability of the two-stage burner to different gas concentrations, calorific values, and inlet gas flow rates. Attached Figure Description

[0029] Figure 1 This is a structural diagram of the low-concentration gas catalytic oxidation reactor of the present invention, which is detachable and suitable for multiple operating conditions.

[0030] Figure 2 This is a schematic diagram of a preheating burner.

[0031] Figure 3 This is a schematic diagram of a high-gas-velocity burner.

[0032] Figure 4 This is a schematic diagram of a two-stage burner.

[0033] Figure 5 This is a diagram showing the structure and location of the limiting ring.

[0034] Explanation of reference numerals in the attached diagram: 1. Fuel cylinder; 2. Air cylinder; 3. Gas distribution box; 4. Mixing chamber; 5. Temperature control digital display device; 6. Thermocouple; 7. Reactor body; 8. First flue gas outlet; 9. Second flue gas outlet; 10. Electrode igniter; 11. Heat exchange coil sealing interface; 12. Reactor top cover; 13. Clamp assembly; 14. Reactor platform; 15. Gas inlet; 16. Gas collection and detection device; 17. Connecting base; 18. Inner flow channel; 19. Heat exchange coil; 20. Catalyst; 21. Outer flow channel; 22. Inner insulation layer; 23. Outer insulation layer; 24. Preheating gas inlet; 25. Venturi flame arrestor; 26. Inner cylinder; 27. Outer cylinder; 28. Upper burner; 29. ​​Lower burner; 30. First catalyst; 31. Second catalyst; 32. Air pump; 33. Inflow pipe; 34. Outflow pipe; 35. Metal perforated plate; 36. Limiting ring. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0036] like Figure 1 As shown, this invention discloses a detachable low-concentration gas catalytic oxidation reactor suitable for multiple operating conditions, comprising a reactor body 7, a reactor cover 12, and a burner. The reactor body 7 has a cylindrical structure with an internal cavity and a connecting base 17 at the bottom. The entire reactor is placed on a reactor platform 14. The reactor cover 12 is connected to the reactor body 7 via a quick-opening mechanism, allowing for rapid separation and closure between the cover and the body. The cavity of the reactor body 7 houses the burner. Different types of burners can be installed depending on the operating conditions, allowing the reactor to be designed as a modular structure for quick replacement of different burners according to varying operating conditions.

[0037] First, the reactor body 7 and the reactor cover 12 are equipped with interface valves necessary for the operation of each burner. Specifically, the reactor body 7 and the reactor cover 12 are provided with burner-specific interfaces, with the reactor cover 12 having a first flue gas outlet 8, an electrode igniter 10, and a heat exchange coil sealing interface 11. Temperature sensor interfaces are provided on the two side walls of the reactor body 7, with each side's temperature sensor interface arranged vertically along the body, for connecting thermocouples to measure the temperature inside the reactor body 7 or the burner. Each temperature sensor interface can be either connected to a sensor or sealed, depending on the actual situation. A second flue gas outlet 9 and a gas inlet 15 are provided at the bottom.

[0038] Secondly, a gas supply device and a gas collection and detection device are installed around the outer periphery of the reactor body 7. The gas supply device includes a fuel cylinder 1, an air cylinder 2, a gas distribution box 3, and a mixing chamber 4. Both fuel cylinder 1 and air cylinder 2 are connected to the gas distribution box 3, which is connected to the mixing chamber 4. The mixing chamber 4 is connected to the air inlet 15 or the heat exchange coil sealing interface 11. The gas collection and detection device is connected to the first flue gas outlet 8 and the second flue gas outlet 9 to detect the flue gas composition. All pipelines involving combustible gases are equipped with flame arresters. The first flue gas outlet 8 and the second flue gas outlet 9 are used for different types of burners; when one flue gas outlet is operating, the other flue gas outlet is closed.

[0039] The reactor cover 12 has a circular protrusion in the middle. The edge of the reactor cover 12 has the same diameter as the edge of the upper opening of the reactor body 7. When the reactor cover and the reactor body 7 are closed, their edges are aligned.

[0040] The quick-opening mechanism is a clamp assembly 13, which includes a clamp body, a screw locking handle, and a locking nut. The clamp body includes two identical semi-circular clamp strips, one end of which is hinged, and the other end is respectively connected to the screw locking handle and the locking nut. The screw locking handle and the locking nut are threadedly connected. The clamp strips have grooves along their length. After the upper edges of the reactor cover and the reactor body are aligned, they are located in the grooves and locked by the screw locking handle and the locking nut. This secures the reactor cover and the reactor body 7, preventing them from separating during operation, facilitating opening for burner replacement, and ensuring that the reactor body is under positive pressure when the burner is burning, thus requiring strong force to press the two together.

[0041] like Figure 5As shown, a connecting base 17 is provided at the bottom of the inner cavity of the reactor body 7. The connecting base 17 includes a limiting ring 36, the inner hole of which communicates with the gas inlet 15. When installing the burner, the bottom of the burner is fitted onto the outer circumference of the limiting ring 36 to radially position the burner and to connect the inside of the burner with the gas inlet 15. This structure facilitates the installation and positioning of the burner, as well as the disassembly and replacement of the burner according to different operating conditions.

[0042] This embodiment includes three types of burners: a preheating burner, a high-gas-velocity burner, and a two-stage burner.

[0043] like Figure 2 As shown, the preheating burner has an open top, spaced a certain distance from the reactor cover 12, allowing flue gas to flow into the reactor body 7 outside the burner. The bottom of the burner is embedded in the connecting base 17 of the reactor body 7. The preheating burner is filled with catalyst 20, and its outer wall is wrapped with heat exchange coils 19. The upper port of the heat exchange coils 19 is connected to the heat exchange coil sealing interface 11, and the outlet end of the heat exchange coils 19 is connected to the preheating gas inlet 24 via a Venturi flame arrestor valve 25, allowing the heat-exchanged mixed gas to enter the burner cavity. The flue gas outlet 9 at the bottom is connected to the inner cavity of the reactor body 7. According to the gas flow path, the gas flow channel inside the burner is designated as the inner layer flow channel 18, and the gas flow channel between the burner and the reactor body 7 is designated as the outer layer flow channel 21. Multiple thermocouples 6 are arranged vertically on both sides of the reactor body 7 and are fed into the inner cavity of the reactor body 7 through a temperature sensor interface. The thermocouple 6 on one side of the reactor body 7 is used to measure the gas temperature in the inner flow channel of the burner, and the thermocouple 6 on the other side of the reactor body 7 is used to measure the gas temperature in the outer flow channel of the burner.

[0044] Specifically, the preheating burner has an inner insulation layer 22 on its shell and an outer insulation layer 23 on the outer surface of the reactor body 7. The preheated gas enters the burner through the preheating gas inlet 24.

[0045] The working principle of the preheating burner is as follows: During operation, the first flue gas outlet 8 is closed, the second flue gas outlet 9 is opened, and the mixing chamber 4 is connected to the heat exchange coil sealing interface 11. The mixing chamber 4 delivers the mixture of methane and air to the heat exchange coil 19. The mixture flows along the heat exchange coil 19 wrapped around the outside of the burner body, enters the bottom of the preheating burner through the outlet end of the heat exchange coil 19, and flows upward through the porous medium catalyst in the inner flow channel 18. After the electrode igniter 10 is turned on, the mixture undergoes catalytic oxidation under the action of the porous medium catalyst.

[0046] The high-temperature flue gas generated by the reaction flows out from the top of the preheating burner, then enters the outer flow channel 21 formed between the burner cylinder and the reactor body 7, and flows downward along the outer flow channel 21. During this process, the high-temperature flue gas exchanges heat with the premixed gas in the heat exchange coil 19, preheating the premixed gas before it enters the burner. The preheated mixed gas continues to enter the inner flow channel 18 to participate in catalytic oxidation, thus forming a thermal cycle process of flue gas waste heat recovery and continuous preheating of the inlet gas. The flue gas after heat exchange is finally discharged from the second flue gas outlet 9 at the bottom of the reactor body 7.

[0047] By cooperating with the aforementioned inner and outer flow channels and heat exchange coil 19, the waste heat of the flue gas can be fully utilized to increase the temperature of the mixed gas entering the catalyst region, improve the ignition and self-sustaining oxidation conditions of low-concentration methane, thereby reducing the risk of unstable reaction or flameout due to low calorific value of the mixed gas or low methane concentration.

[0048] like Figure 3 As shown, the high-gas-velocity burner has an inner cylinder 26 and an outer cylinder 27, with the top of the burner contacting the inner side of the reactor cover 12. The inner cylinder 26 is a porous cylinder, and the outer cylinder 27 also has porous walls. The inner cylinder 26 is embedded outside the limiting ring. A catalyst zone is formed in the space between the inner cylinder 26 and the outer cylinder 27 for filling with catalyst 20. The inner cylinder 26 is a screen-type cylinder for gas passage. Thermocouples 6 extend from both sides of the reactor body 7 through temperature sensor interfaces into the porous catalyst zone (oxidation zone) and the gas flow zone of the inner cylinder, respectively.

[0049] The high-gas-velocity burner operates as follows: When the high-gas-velocity burner is working, the gas inlet 15 and the first flue gas outlet 8 are opened, while the second flue gas outlet 9 is closed. The mixed gas enters the inner cylinder from the gas inlet 15 at the bottom of the reactor body, and flows through the pores of the inner cylinder 26 into the porous medium catalyst zone between the inner cylinder 26 and the outer cylinder 27. The electrode igniter 10 is activated, and the mixed gas reacts in the porous medium catalyst zone. The generated high-temperature flue gas flows from the holes of the outer cylinder 27 into the space between the outer cylinder 27 and the reactor body 7, and then exits from the first flue gas outlet 8 at the top.

[0050] The high-gas-velocity burner employs an inner cylinder 26, an outer cylinder 27, and an annular catalyst zone located between them, forming a radially split-flow combustion structure. The inner cylinder 26 has multiple vents distributed along its height and circumference. This allows the high-speed mixed gas entering the inner cylinder 26 axially from the gas inlet 15 to no longer directly impact the catalyst along a single axial flow path. Instead, it is split at multiple points through vents at different heights and circumferential positions, and then enters the catalyst zone radially. This combination of axial flow convergence and radial flow splitting increases the effective contact range between the mixed gas and the catalyst zone, weakens the local concentration effect of the high-speed gas flow, and makes the gas flow rate and reaction load distribution within the catalyst zone more uniform, while reducing local pressure pulsations. Therefore, this structure improves flow field stability under high-gas-velocity conditions, reduces the risks of flashback, flameout, and thermoacoustic vibration, and enables stable catalytic oxidation of low-concentration methane even at higher inlet velocities.

[0051] like Figure 4 As shown, the two-stage burner includes an upper burner 28 and a lower burner 29. The bottom inner cavity of the lower burner 29 is fitted outside the limiting ring 36 to achieve the installation and positioning of the lower burner 29 within the reactor body 7; the bottom of the upper burner 28 is fitted with the upper opening of the lower burner 29, thus forming a two-stage combustion structure connected in series. The inner bottom of the upper burner 28 and the lower burner 29 are respectively provided with a porous metal plate 35 to support the corresponding porous media catalyst.

[0052] The upper burner 28 contains a first catalytic reaction zone filled with a highly active precious metal catalytic medium. This zone further catalytically oxidizes the residual combustible components after primary oxidation in the lower burner 29, thereby improving the overall conversion rate of the combustible components. The lower burner 29 contains a second catalytic reaction zone filled with a high-temperature resistant and low-cost porous catalytic medium. This zone performs primary catalytic oxidation on the low-concentration methane entering from the bottom of the reactor. A thermocouple 6 extends from a temperature sensor interface on one side of the reactor body 7, connecting to the catalytic reaction zones of both the upper burner 28 and the lower burner 29 to detect the temperatures of the first and second catalytic reaction zones.

[0053] Under this operating condition, an external air pump 32 is connected. The air pump 32 has two insulated pipes: a gas inlet pipe 33 and a gas outlet pipe 34. One end of the gas inlet pipe 33 is connected to the upper opening of the combustion zone of the upper burner 28, and the other end is connected to the air pump 32. One end of the outlet pipe 34 is connected to the air pump 32, and the other end is connected to the space between the upper burner 28 and the lower burner 29.

[0054] The working principle of the two-stage burner is as follows: During operation, the gas inlet 15 and the first flue gas outlet 8 are opened, while the second flue gas outlet 9 is closed. The mixed gas enters the lower burner 29 through the gas inlet 15 at the bottom of the reactor body 7, first passing through the second catalytic reaction zone. After the electrode igniter 10 is turned on, the mixed gas undergoes primary catalytic oxidation under the action of the high-temperature resistant porous catalytic medium packed in the second catalytic reaction zone. The gas after primary catalytic oxidation continues to flow upward and enters the first catalytic reaction zone in the upper burner 28, where it undergoes further catalytic oxidation under the action of the highly catalytically active first catalyst 30 to promote the deep conversion of residual combustible components. Through the series coordination of the upper and lower catalytic reaction zones, the low-concentration gas completes primary oxidation and deep oxidation sequentially, thereby improving the overall conversion rate of combustible components and reducing the content of residual combustible components in the exhaust gas.

[0055] High-temperature flue gas flows out from the first flue gas outlet 8 at the top of the reactor body 7, while the second flue gas outlet 9 is closed. A portion of the high-temperature flue gas is drawn into the inlet pipe 33 and pumped to the extraction pump 32, then returned to the bottom of the upper burner 28 via the outlet pipe 34. By setting up the extraction pump 32 and utilizing the inlet pipe 33 and outlet pipe 34 to form a high-temperature flue gas circulation loop, a portion of the high-temperature flue gas at the outlet of the upper burner 28 is extracted and re-transported to the area between the upper burner 28 and the lower burner 29. This utilizes the residual heat of the high-temperature flue gas to preheat the gas entering the upper burner 28, increasing the gas temperature at the inlet of the upper burner 28, improving the ignition and reaction conditions of low-concentration methane under low calorific value conditions, and reducing the risk of flameout due to insufficient temperature. Simultaneously, the directional circulation of the high-temperature flue gas enhances heat transfer between the upper and lower burners, resulting in a more uniform temperature distribution inside the reactor, promoting further oxidation of residual combustible components in the upper burner, and improving the overall conversion rate and reaction stability of the low-concentration methane. By adjusting the circulating flue gas flow rate through the extraction pump, the thermal cycle intensity can also be adjusted according to operating parameters such as gas concentration and air intake flow rate, thereby improving the adaptability of the two-stage burner to different operating conditions.

[0056] In summary, this embodiment allows the reactor to adapt to low-concentration gas catalytic oxidation conditions under different concentrations, flow rates, and thermal cycling requirements by detachably installing a preheating burner, a high-gas-velocity burner, or a two-stage burner within the same reactor body. The preheating burner utilizes waste heat from the flue gas to preheat the mixed gas; the high-gas-velocity burner improves gas distribution through its inner and outer cylinder structure; and the two-stage burner promotes the full reaction of combustible components through segmented catalysis and high-temperature gas circulation. Each burner can share gas supply, ignition, temperature detection, and flue gas detection devices, and can be disassembled and reassembled via the reactor cover and connecting base 17, facilitating operating condition switching, testing, and routine maintenance.

[0057] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes that can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention are all within the protection scope of the claims of the present invention.

Claims

1. A detachable, multi-condition low-concentration gas catalytic oxidation reactor, characterized in that, It includes the reactor body, reactor cover, burner, gas supply device, and gas collection and detection device; The reactor body has an internal cavity for accommodating the burner. A connecting base is provided at the bottom of the internal cavity. The burner is disposed in the internal cavity and is detachably connected to the connecting base so that the burner can be installed or removed through the upper opening of the internal cavity of the reactor body. The reactor cover is located on the upper opening of the inner cavity of the reactor body and is detachably connected to the reactor body via a quick-opening mechanism. The reactor cover is provided with a first flue gas outlet, an electrode igniter and a heat exchange coil sealing interface. The reactor body is provided with a gas inlet, a second flue gas outlet and multiple temperature sensor interfaces. Valves are provided at the first flue gas outlet, the second flue gas outlet, the gas inlet and the heat exchange coil sealing interface respectively. The gas supply device is selectively connected to the gas inlet and / or the heat exchange coil sealing interface, and is used to supply premixed gas to the burner; The gas collection and detection device is selectively connected to the first flue gas outlet and / or the second flue gas outlet, and is used to collect and detect the flue gas generated by the burner; The burner is any one of a preheating burner, a high-gas-velocity burner, or a two-stage burner, and different types of burners can be selectively installed in the reactor body according to the operating conditions.

2. The low-concentration gas catalytic oxidation reactor suitable for multiple operating conditions and capable of being disassembled, as described in claim 1, is characterized in that... The quick-opening mechanism is a clamp assembly, which includes a clamp body, a screw locking handle, and a locking nut. The clamp body includes two identical semi-circular clamp strips, one end of which is hinged, and the other end is respectively connected to the screw locking handle and the locking nut. The screw locking handle is threadedly connected to the locking nut. The clamp strips have a groove along their length. After the upper edge of the reactor cover and the upper edge of the reactor body are aligned, they are located in the groove and locked by the screw locking handle and the locking nut threadedly.

3. The low-concentration gas catalytic oxidation reactor suitable for multiple operating conditions and capable of being disassembled, as described in claim 1, is characterized in that... The gas supply device includes a fuel gas cylinder, an air cylinder, a mixing chamber, and a gas distribution box. The fuel gas cylinder and the air cylinder are both connected to the gas distribution box, the gas distribution box is connected to the mixing chamber, and the mixing chamber is connected to the gas inlet pipeline.

4. The low-concentration gas catalytic oxidation reactor suitable for multiple operating conditions and capable of being disassembled, as described in claim 1, is characterized in that... The preheating burner has a cylindrical structure with an open upper end, forming a flue gas flow space between it and the reactor cover. The preheating burner is filled with a catalyst, and its outer wall is wound with heat exchange coils. The inlet end of the heat exchange coils is connected to a sealed interface, and the outlet end is connected to a preheating gas inlet located at the lower part of the side wall of the preheating burner. An inner flow channel is formed inside the preheating burner, and an outer flow channel is formed between the preheating burner and the reactor body. The inner and outer flow channels are connected via the open upper end of the preheating burner. The outer flow channel is connected to the second flue gas outlet so that the high-temperature flue gas generated by the preheating burner enters the outer flow channel through its upper opening and exchanges heat with the gas mixture to be combusted in the heat exchange coil when it flows through the heat exchange coil, and then is discharged through the second flue gas outlet; the two side walls of the reactor body are respectively provided with multiple temperature sensor interfaces arranged at intervals in the vertical direction, one side of which is used to install a thermocouple to measure the temperature of the inner flow channel, and the other side of which is used to install a thermocouple to measure the temperature of the outer flow channel.

5. The low-concentration gas catalytic oxidation reactor suitable for multiple operating conditions and capable of being disassembled, as described in claim 4, is characterized in that... The burner cylinder wall is provided with an inner insulation layer, and the reactor main cylinder wall is provided with an outer insulation layer.

6. The low-concentration gas catalytic oxidation reactor suitable for multiple operating conditions and capable of being disassembled, as described in claim 1, is characterized in that... The high-gas-velocity burner includes an inner cylinder and an outer cylinder arranged coaxially. An annular catalytic reaction zone is formed between the inner cylinder and the outer cylinder, and a catalyst is filled in the annular catalytic reaction zone. The lower end of the inner cylinder is detachably connected to the connecting base and communicates with the gas inlet. The inner cylinder wall is provided with a plurality of first vent holes at intervals along the circumference and axial direction, so that the mixed gas entering the inner cylinder from the gas inlet is dispersed through the plurality of first vent holes and enters the annular catalytic reaction zone radially. The outer cylinder is arranged around the outside of the inner cylinder. The outer cylinder wall is provided with a plurality of second vent holes so that the flue gas after catalytic reaction in the annular catalytic reaction zone is discharged through the plurality of second vent holes to the flue gas flow channel between the outer cylinder and the reactor body, and is discharged through the first flue gas outlet. The top of the inner cylinder is closed or sealed with the reactor cover to restrict the mixed gas from flowing directly out along the axial direction of the inner cylinder, so that the mixed gas entering the inner cylinder flows radially into the annular catalytic reaction zone through the first vent holes.

7. The low-concentration gas catalytic oxidation reactor suitable for multiple operating conditions and capable of being disassembled, as described in claim 1, is characterized in that... The two-stage burner includes an upper burner and a lower burner. The bottom of the lower burner is detachably connected to the connecting base, and the upper part of the lower burner is detachably connected to the upper burner. The upper and lower burners are respectively filled with different types of porous catalytic media. Multiple temperature sensor interfaces are provided on one side of the reactor body, and thermocouples are inserted into the upper and lower burners through these interfaces to measure the combustion temperature within both burners. A vacuum pump is provided on the other side of the reactor body. The vacuum pump is connected to the outlet of the upper burner via an inflow pipe and to the space between the upper and lower burners via an outflow pipe, thereby drawing a portion of the high-temperature flue gas from the outlet of the upper burner back to the space between the upper and lower burners. The gas inlet is connected to the lower burner, and the first flue gas outlet is connected to the outlet side of the upper burner.

8. The low-concentration gas catalytic oxidation reactor suitable for multiple operating conditions and capable of being disassembled, as described in claim 1, is characterized in that... It also includes a reactor platform, on which the reactor body is mounted.

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