A catalytic oxidation system and burner for low-concentration methane

Abstract

The present invention discloses a catalytic oxidation system and a burner for diluted mine gas. The catalytic oxidation system for diluted mine gas includes: a catalytic reaction unit and a countercurrent gas path device; the countercurrent gas path device is communicated with the catalytic reaction unit; the catalytic reaction unit includes annular honeycomb ceramic heat storage bricks. The catalytic oxidation system for diluted mine gas of the present invention is provided with a countercurrent gas path device and annular honeycomb ceramic heat storage bricks. The annular honeycomb ceramic heat storage bricks can effectively increase the surface area of the carrier and enhance the heat storage capacity. The countercurrent gas path device can alternately heat the diluted mine gas, improve the conversion rate of the diluted mine gas, and reduce energy consumption, thereby realizing the self-sustaining operation of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of utilization of ventilation air methane, and in particular to a catalytic oxidation system and a burner for ventilation air methane. Background Art

[0002] If a large amount of ventilation air methane (methane content < 0.75 vol%) gushes out during coal mining and is directly discharged into the atmosphere, it will cause serious waste of resources and environmental pollution. Methane, the main component of ventilation air methane, is a strong greenhouse gas, and its global warming potential (GWP20) on a 20-year scale is about 84 - 87 times that of carbon dioxide. For every 100 million cubic meters of methane utilized, it is equivalent to reducing emissions of 1.5 million tons of carbon dioxide. Therefore, the efficient utilization of ventilation air methane in coal mines has great practical significance for the development of clean energy, ensuring the safe production of coal mines, reducing greenhouse gas emissions, and realizing the sustainable development of energy.

[0003] Since the concentration and flow rate of ventilation air methane will be affected by factors such as ventilation volume and mining volume during the mining process, when its concentration is lower than the lean combustion limit, it cannot be treated by conventional combustion methods, so it is difficult to utilize and the utilization ratio is extremely low. Catalytic combustion is a flameless combustion carried out with the aid of a catalyst at a lower ignition temperature, which can decompose methane into carbon dioxide, water and energy, and at the same time reduce the emissions of pollutant gases such as NOx and CO during the treatment process. However, the catalytic oxidation utilization system for ventilation air methane still has problems of high energy consumption during the reaction process and low conversion efficiency, which limits the industrial application of this technology. Summary of the Invention

[0004] The object of the present invention is to provide a catalytic oxidation system and a burner for ventilation air methane to reduce the energy consumption during the reaction process and improve the conversion efficiency.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A catalytic oxidation system for ventilation air methane, the catalytic oxidation system for ventilation air methane includes: a catalytic reaction unit and a countercurrent gas path device;

[0007] The countercurrent gas path device is communicated with the catalytic reaction unit;

[0008] The catalytic reaction unit includes a ring-shaped honeycomb ceramic heat storage brick, and the ring-shaped honeycomb ceramic heat storage brick is used for loading a catalyst.

[0009] Optionally, the countercurrent gas path device includes an air compressor, a methane gas cylinder, a mixing tank, a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve and an annular pipeline;

[0010] The first solenoid valve, the second solenoid valve, the third solenoid valve and the fourth solenoid valve are distributed on the annular pipeline;

[0011] The air compressor and the methane gas cylinder are both connected to the inlet of the gas mixing tank, and the outlet of the gas mixing tank is connected to a first preset position of the annular pipeline; the first preset position is located between the first electromagnetic valve and the second electromagnetic valve;

[0012] A first port of the catalytic reaction unit is connected to a second preset position of the annular pipeline, a second port of the catalytic reaction unit is connected to a third preset position of the annular pipeline, the second preset position is located between the first electromagnetic valve and the third electromagnetic valve, and the third preset position is located between the second electromagnetic valve and the fourth electromagnetic valve;

[0013] An air outlet is provided at a fourth preset position of the annular pipeline, and the fourth preset position is located between the third electromagnetic valve and the fourth electromagnetic valve.

[0014] Optionally, the countercurrent air-gas intake device further includes a temperature measuring device and a temperature data acquisition module, and the temperature measuring device includes a plurality of thermocouples;

[0015] The plurality of thermocouples are evenly distributed inside the catalytic reaction unit;

[0016] The temperature data acquisition module is connected to each thermocouple.

[0017] Optionally, the number of pores on the surface of the annular honeycomb ceramic heat storage brick is: 4(M1 + M2 + M3), and the total area of the catalyst loaded on the annular honeycomb ceramic heat storage brick is: 4(M1 + M2 + M3)×4aL;

[0018] Among them, M1 is the number of first pores in the 1 / 4 part. When (A / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 > 0, and (B / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 > 0,

[0019]

[0020] M2 is the number of second pores in the 1 / 4 part. When (A / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 > 0, and (B / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 ≤ 0,

[0021]

[0022] M3 is the number of the third holes in the 1 / 4 part. When (A / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 ≤0, and (B / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 ≤0, M3 = 0;

[0023] a is the aperture of the pore channel, L is the length of the pore channel, A and B are respectively the outer diameter and the inner diameter of the annular honeycomb ceramic regenerator brick, n is the number of the current layer of the annular honeycomb ceramic regenerator brick, and δ is the wall thickness of the pore channel.

[0024] Optionally, the burner includes: a pulverized coal combustion system and the above-mentioned exhausted air gas catalytic oxidation system;

[0025] The pulverized coal combustion system is arranged inside the ring of the annular honeycomb ceramic regenerator brick of the exhausted air gas catalytic oxidation system for providing heat for the exhausted air gas catalytic oxidation system.

[0026] Optionally, the pulverized coal combustion system includes a powder supply device, an annular heating device, and a pulverized coal combustion chamber; the pulverized coal combustion chamber is a cylindrical reaction pipeline;

[0027] The pulverized coal combustion chamber is arranged inside the ring of the heating device, and the heating device is arranged inside the ring of the annular honeycomb ceramic regenerator brick;

[0028] The powder supply device is communicated with the pulverized coal combustion chamber.

[0029] Optionally, the powder supply device includes a pulverized coal bin, a continuous powder feeder, a blower, a coke collection device, and a filter cartridge;

[0030] The continuous powder feeder and the blower are both communicated with the powder inlet of the pulverized coal combustion chamber, and the continuous powder feeder is also communicated with the pulverized coal bin;

[0031] The coke collection device and the filter cartridge are both communicated with the powder outlet of the pulverized coal combustion chamber.

[0032] Optionally, the burner further includes a heat energy recovery and utilization system;

[0033] The heat energy recovery and utilization system includes a water tank, a steam turbine system, and a generator;

[0034] The exhausted air gas catalytic oxidation system is arranged inside the water tank, the steam turbine system is communicated with the steam outlet of the water tank, and the steam turbine system is shaft-connected with the generator.

[0035] Optionally, the steam turbine system includes a water outlet tank, a filter screen, blades, and a steam turbine;

[0036] The water outlet tank is communicated with the steam outlet of the water tank, and the filter screen is arranged at the steam outlet of the water tank;

[0037] The blades are located in the water outlet tank. The blades are communicated with the steam turbine through a pipeline, and the output shaft of the steam turbine is connected to the generator shaft.

[0038] Optionally, a first gas detection port, a second gas detection port and a third gas detection port are arranged on the burner;

[0039] The first gas detection port is located at the outlet of the gas mixing tank of the exhausted air gas catalytic oxidation system;

[0040] The second gas detection port is located at the air outlet arranged on the annular pipeline of the exhausted air gas catalytic oxidation system;

[0041] The third gas detection port is located at the air outlet of the filter cartridge of the pulverized coal combustion system;

[0042] The first gas detection port, the second gas detection port and the third gas detection port are all used to connect an on-line methane analyzer.

[0043] According to the specific embodiments provided by the present invention, the following technical effects are disclosed by the present invention:

[0044] The present invention discloses an exhausted air gas catalytic oxidation system and a burner. The exhausted air gas catalytic oxidation system includes: a catalytic reaction unit and a countercurrent gas path device; the countercurrent gas path device is communicated with the catalytic reaction unit; the catalytic reaction unit includes annular honeycomb ceramic heat storage bricks. The exhausted air gas catalytic oxidation system of the present invention is provided with a countercurrent gas path device and annular honeycomb ceramic heat storage bricks. The annular honeycomb ceramic heat storage bricks can effectively increase the surface area of the carrier and enhance the heat storage capacity. The countercurrent gas path device can alternately heat the exhausted air gas, improve the conversion rate of the exhausted air gas and reduce the energy consumption, so as to realize the self-sustaining operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in 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.

[0046] Figure 1 It is a schematic structural diagram of a dual-channel countercurrent burner for exhausted air gas provided by an embodiment of the present invention;

[0047] Figure 2An axial side view of a low-concentration gas dual-channel countercurrent burner provided by an embodiment of the present invention;

[0048] Reference numerals:

[0049] 1 - air compressor; 2 - first pressure reducing valve; 3 - second pressure reducing valve; 4 - first mass flowmeter; 5 - second mass flowmeter; 6 - methane gas cylinder; 7 - gas mixing tank; 8 - first solenoid valve; 9 - second solenoid valve; 10 - third solenoid valve; 11 - fourth solenoid valve; 12 - first cover; 13 - second cover; 14 - on-line methane analyzer; 15 - first gas detection port; 16 - second gas detection port; 17 - thermocouple port; 18 - temperature data acquisition module; 19 - pulverized coal bin; 20 - continuous powder feeder; 21 - blower; 22 - powder inlet; 23 - powder outlet; 24 - coke collection device; 25 - filter cartridge; 26 - third gas detection port; 27 - water tank; 28 - water inlet; 29 - water outlet tank; 30 - steam turbine; 31 - generator; 32 - filter screen; 33 - blade; 34 - annular honeycomb ceramic heat storage brick; 35 - heat conduction layer; 36 - heating device. Detailed implementation manners

[0050] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with 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.

[0051] The object of the present invention is to provide a low-concentration gas catalytic oxidation system and a burner to reduce the energy consumption during the reaction process and improve the conversion efficiency.

[0052] 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 in conjunction with the accompanying drawings and specific implementation manners.

[0053] Embodiment 1

[0054] As Figure 1 and 2 shown, Embodiment 1 of the present invention provides a low-concentration gas catalytic oxidation system, including a catalytic reaction unit, a countercurrent gas path device and a temperature measuring device.

[0055] In this embodiment, the catalytic reaction unit is a plurality of annular honeycomb ceramic heat storage bricks 34, and the inner walls of the ceramics are all used for loading catalysts.

[0056] In this embodiment, the material of the above-mentioned annular honeycomb ceramic heat storage brick 34 is preferably a high-temperature heat storage material such as mullite ceramic. The heat transfer performance of the annular honeycomb ceramic heat storage brick 34 is described according to the temperature efficiency E and the waste heat recovery rate R:

[0057]

[0058]

[0059] wherein, t' air , t″ air respectively represent the inlet and outlet temperatures of the air, in °C; represents the inlet temperature of the exhausted air gas, in °C; M air , respectively represent the mass flow rates of the air and methane, in m 3 / h; C air , respectively represent the specific heat capacities of the air and methane, in kJ / (m 3 ·°C).

[0060] In this embodiment, the shape of the internal pores of the annular honeycomb ceramic heat storage brick 34 is square. Among them, the cross-sectional area of the square pore unit channel is, and the porosity is a 2 / (a + 2δ) 2 , and the specific surface area is 4a / (a + 2δ) 2 , where a is the side length of the pore and δ is the wall thickness of the pore;

[0061] The surface area on which the catalyst can be loaded is equal to the inner surface area of the honeycomb ceramic pores. The inner surface area of the square pore unit is 4aL, where L is the pore length; the total surface area on which the annular honeycomb ceramic heat storage brick 34 can be loaded with the catalyst is equal to the number of ceramic pores × the inner surface area. When only the pore diameter a and the wall thickness δ are known, the number of pores on a single ceramic can be estimated according to the outer ring diameter A and the inner ring diameter B according to the following steps: First, divide the annular honeycomb ceramic heat storage brick 34 into four equal parts, and the number of ceramic pores in the 1 / 4 part satisfies:

[0062] Case 1: When (A / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 > 0, and (B / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 > 0,

[0063]

[0064] wherein, M1 is rounded to an integer, and n is the number of layers where each layer of pores is located, which is sequentially counted from the diameter axis of the annular honeycomb ceramic heat storage brick 34 to the outside of the annular honeycomb ceramic heat storage brick 34;

[0065] Case 2: When (A / 2) 2 -{(2n - 1)×[(aa + δ) / 2]} 2 > 0, and (B / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 ≤ 0,

[0066]

[0067] wherein, M2 is rounded to an integer, n is the layer number where each layer of channels is located, which is sequentially counted from the diameter axis of the annular honeycomb ceramic regenerator brick 34 to the outside of the annular honeycomb ceramic regenerator brick 34;

[0068] Case 3: When (A / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 ≤ 0, and (B / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 ≤ 0, M3 = 0;

[0069] Therefore, there are a total of 4(M1 + M2 + M3) channels on the surface of the annular honeycomb ceramic regenerator brick 34, and the total area that can carry the catalyst is equal to 4(M1 + M2 + M3)×4aL. Since the shapes of some channels of the honeycomb ceramic regenerator brick may be incomplete during the production and processing process, this calculation method only estimates the number of channels, and the quantity is subject to the actually produced ceramics.

[0070] The calculation method for the total area that the above annular honeycomb ceramic regenerator brick 34 can carry the catalyst is as follows:

[0071] (1) The annular honeycomb ceramic regenerator brick 34 with an outer ring diameter A = 68 mm, an inner ring diameter B = 30 mm, a length L = 50 mm, and a square surface channel shape with a pore diameter a = 3 mm and a wall thickness δ = 0.8 mm is divided into four equal parts.

[0072] (2) Calculate the number of pores of 1 / 4 of the annular honeycomb ceramic regenerator brick 34: Substitute A, B, a, δ, (A / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 =(68 / 2) 2 -{(2n - 1)×[(3 + 0.8) / 2]} 2 = 1156 - 3.61(2n - 1) 2 , (B / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 =(30 / 2) 2 -{(2n - 1)×[(3 + 0.8) / 2]}2 , it can be known that when n < 9.45, (A / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 > 0, when n < 4.45, (B / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 > 0, and when n ≥ 9.45, (A / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 ≤0, when n ≥ 4.45, (B / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 ≥0;

[0073] Therefore, when n = 1, 2, 3, 4, it simultaneously satisfies (A / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 > 0, (B / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 > 0. According to the formula,

[0074]

[0075] it is obtained that M1 are 5 (n = 1), 5 (n = 2), 6 (n = 3), 6 (n = 4) respectively;

[0076] When n = 5, 6, 7, 8, 9, it simultaneously satisfies (A / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 > 0, (B / 2) 2 -{(2n - 1)×[(a + δ) / 2]} 2 < 0. According to the formula,

[0077]

[0078] it is obtained that M2 are 8 (n = 5), 7 (n = 6), 6 (n = 7), 5 (n = 8), 3 (n = 9) respectively;

[0079] When n > 9, M3 = 0;

[0080] (3) The surface of the annular honeycomb ceramic heat storage brick 34 has a total of 4(M1 + M2 + M3) = 204 pore channels, and the total area that can carry the catalyst is equal to 4(M1 + M2 + M3)×4aL = 122400mm 2 . Since there will be a situation where the shapes of some pore channels of the honeycomb ceramic heat storage brick are incomplete during the production and processing process, this calculation method only estimates the number of pore channels, and the quantity is subject to the actual production of ceramics.

[0081] In this embodiment, the countercurrent gas path device includes a goaf gas inlet device and a clean gas exhaust device. Among them, the goaf gas inlet device includes an air compressor 1, a methane gas cylinder 6, a gas mixing tank 7, a first solenoid valve 8, a second solenoid valve 8, a third solenoid valve 10, a fourth solenoid valve 11, and an annular pipeline ( Figure 1 and 2 not shown in). As Figure 1 shown, the first solenoid valve 8, the second solenoid valve 9, the third solenoid valve 10, and the fourth solenoid valve 11 are distributed on the annular pipeline; both the air compressor 1 and the methane gas cylinder 6 are connected to the inlet of the gas mixing tank 7, and the outlet of the gas mixing tank 7 is connected to the first preset position of the annular pipeline; the first preset position is between the first solenoid valve 8 and the second solenoid valve 9; the first port of the catalytic reaction unit is connected to the second preset position of the annular pipeline, and the second port of the catalytic reaction unit is connected to the third preset position of the annular pipeline. The second preset position is between the first solenoid valve 8 and the third solenoid valve 10, and the third preset position is between the second solenoid valve 8 and the fourth solenoid valve 11; an air outlet (this air outlet is the above-mentioned clean gas exhaust device) is provided at the fourth preset position of the annular pipeline, and the fourth preset position is between the third solenoid valve 10 and the fourth solenoid valve 11.

[0082] Exemplarily, the diluted wind gas inlet device further includes a first pressure reducing valve 2 and a second pressure reducing valve 3, a first mass flowmeter 4 and a second mass flowmeter 5, a first cover 12 connected to the front end of the catalytic reaction unit, and a second cover 13 connected to the tail end of the catalytic reaction unit; a first gas detection port 15 is provided at the outlet position of the mixing tank 7, and a clean gas exhaust device, that is, a second gas detection port 16 is provided at the outlet position as described above. The first gas detection port 15 and the second gas detection port 16 are connected to an on-line methane analyzer 14; during the working process, the required concentration of diluted wind gas is prepared in the mixing tank 7 by an air compressor 1 and a methane gas cylinder 6. In the first cycle, the first solenoid valve 8 and the fourth solenoid valve 11 are opened simultaneously, and the second solenoid valve 9 and the third solenoid valve 10 are closed. The diluted wind gas flows through the first solenoid valve 8 and enters the inside of the annular honeycomb ceramic regenerator brick 34 through the ports (four air inlets) on the first cover 12, and then is discharged through the second cover 13 and the fourth solenoid valve 11; in the second cycle, the first solenoid valve 8 and the fourth solenoid valve 11 are closed, and the second solenoid valve 9 and the third solenoid valve 10 are opened simultaneously. The flow direction of the diluted wind gas changes, and it enters the inside of the annular honeycomb ceramic regenerator brick 34 through the ports (4 air inlets) on the second cover 13 through the second solenoid valve 9, and then is discharged through the first cover 12 and the third solenoid valve 10. Repeat the first and second cycles in this step; during the working process, the methane concentrations before and after the reaction are measured by the first gas detection port 15 and the second gas detection port 16 connected to the on-line methane analyzer 14 respectively; due to the cyclic switching period process, the heat generated by the reaction of the gas flow can repeatedly heat the annular honeycomb ceramic regenerator brick 34, and at the same time, the heat stored in the annular honeycomb ceramic regenerator brick 34 heats the diluted wind gas flow, so that the diluted wind gas is always in a state of being alternately heated, thereby realizing the self-sustaining operation of the device.

[0083] In this embodiment, the temperature measuring device includes a plurality of thermocouples, and the temperature is measured by penetrating into the inside of the regenerator brick through the surface pores of the annular honeycomb ceramic regenerator brick 34, and is evenly distributed in the catalytic reaction unit. The thermocouple port 17 is connected to the temperature data acquisition module 18.

[0084] In summary, the low-concentration ventilation air methane catalytic oxidation system proposed in this technical solution includes a catalytic reaction unit, a countercurrent gas path device, and a temperature measurement device. The annular honeycomb ceramic regenerator brick 34 can effectively increase the surface area of the carrier and enhance the heat storage capacity. The countercurrent gas path device can alternately heat the low-concentration ventilation air methane to improve the conversion rate of low-concentration ventilation air methane and achieve the self-sustaining operation of the device. The temperature measurement device can effectively measure the internal temperature of the annular honeycomb ceramic regenerator brick 34 to provide data for subsequent heat calculation; a general formula for calculating the number of holes is deduced, which is applicable to any annular honeycomb ceramic regenerator brick 34 with square channels on its surface. Therefore, the low-concentration ventilation air methane catalytic oxidation system proposed in this embodiment overcomes the deficiencies of the existing low-concentration ventilation air methane catalytic oxidation system, such as the small catalyst loadable area, the inability to theoretically calculate the number of holes on the honeycomb ceramic surface, and the large reaction energy consumption.

[0085] Embodiment 2

[0086] This embodiment proposes a dual-channel countercurrent burner for low-concentration ventilation air methane. The burner includes a pulverized coal combustion system and the low-concentration ventilation air methane catalytic oxidation system in Embodiment 1, where the pulverized coal combustion system includes a powder supply device, a heating device 36, and a pulverized coal combustion chamber.

[0087] As Figure 1 shown, the above powder supply device mainly includes: a pulverized coal bin 19, a continuous powder feeder 20, a blower 21, a powder inlet 22, a powder outlet 23, a coke collection device 24, a filter cartridge 25, and a third gas detection port 26 connected to the on-line methane analyzer 14. In this embodiment, the pulverized coal controls the binning speed through the blower 21 and enters the internal pulverized coal combustion pipeline of the pulverized coal combustion chamber through the powder inlet 22;

[0088] As Figure 2 shown, the above heating device 36 is wrapped around the outer layer of the pulverized coal combustion pipeline and is embedded in the inner ring of the annular honeycomb ceramic regenerator brick 34. During the working process, the temperature of the heating device is controlled by a temperature controller to provide the heat required for pulverized coal combustion. Through the heat supply of the heating device, the pulverized coal burns and generates heat in the combustion chamber inside the heating device ring.

[0089] The above pulverized coal combustion chamber is a cylindrical reaction pipeline and is built inside the inner ring of the annular honeycomb ceramic regenerator brick 34; the injected pulverized coal burns in a suspended state in the cylindrical reaction pipeline, that is, ρV>m is satisfied, where ρ represents the air density, kg / m 3 , V represents the volume of the displaced gas, m 3, where \(m\) represents the mass of pulverized coal, in kg. Among them, too high an ash content will reduce the tuyere flame temperature, reduce the activity of the coal, and affect the ignition and combustion of the pulverized coal. Therefore, a coal sample with an ash content lower than or close to that of coke is selected, with a maximum not exceeding 15%. The higher the volatile matter, the more complete the combustion of the coal. To ensure the full combustion of the pulverized coal, a coal sample with a higher volatile matter is selected. To ensure that the combustion concentration of the pulverized coal is far lower than the lower explosion limit of the pulverized coal, a pulverized coal concentration with a lower explosion limit of 20% is selected.

[0090] According to the combustion heat balance, the combustion temperature \(T\) of the pulverized coal can be obtained coal , in °C;

[0091]

[0092] Among them, \(Q\) net,ad represents the lower calorific value of the fuel on an air-dried basis, in kJ / kg; \(Q\) air represents the physical heat brought in by the air, in kJ / kg; \(Q\) coal represents the physical heat brought in by the pulverized coal, in kJ / kg; \(Q\) co represents the incomplete combustion heat loss of CO, in kJ / kg; \(V\) gas is the gas combustion product generation amount, in Nm 3 / kg; \(C\) gas represents the average specific heat of the gas combustion products, in kJ / (Nm 3 / ·K); \(C\) ash represents the average heat capacity of the ash in the combustion products, in kJ / (Nm 3 / ·K); \(m\) ash represents the mass of the coal ash in the combustion products, in kg;

[0093] In this embodiment, anthracite with low sulfur and low temperature is used;

[0094] In this embodiment, to ensure that the pulverized coal concentration is far lower than the lower explosion limit of the pulverized coal, a pulverized coal concentration with a lower explosion limit of 20% is selected;

[0095] In this embodiment, the temperature of the heating device is controlled by a temperature controller, and the temperature is raised from room temperature to the set temperature and kept for 1 h to make the temperature distribution in the pipeline uniform.

[0096] In this embodiment, pulverized coal with the same concentration is continuously injected for 1 h to transfer heat to the exhausted air gas catalytic oxidation device, and the internal temperature of the exhausted air gas catalytic oxidation device is measured by a thermocouple.

[0097] In summary, the pulverized coal combustion system proposed in this technical solution includes a coal powder supply device, a heating device, and a pulverized coal combustion chamber. Using inexpensive pulverized coal as raw material, air volume is provided to the pulverized coal by a blower, so that the pulverized coal is evenly distributed in the reaction pipeline in a suspended state, and a relatively low temperature value is applied to the pulverized coal combustion pipeline. The pulverized coal is heated and starts to release heat, and the released heat is used for the lean gas catalytic oxidation system. Therefore, the pulverized coal combustion system proposed in this technical solution overcomes the deficiencies of high energy consumption, large heat loss, and high operating cost in the existing lean gas catalytic oxidation system.

[0098] Embodiment 3

[0099] As Figure 1 and Figure 2 shown, the lean gas two-channel countercurrent burner provided in this Embodiment 3 further includes a heat energy recovery and utilization system on the basis of the structure of Embodiment 2. The heat energy recovery and utilization system includes a water tank 27, a steam turbine system, and a generator 31; the lean gas catalytic oxidation system is arranged in the water tank 27, and the steam turbine system is communicated with the steam outlet of the water tank 27. The steam turbine system includes a water outlet tank 29, a filter screen 32, and a steam turbine 30; the water outlet tank 29 is communicated with the steam outlet of the water tank 27, and the filter screen 32 is arranged at the steam outlet of the water tank 27; the blades 33 of the steam turbine 30 are located in the water outlet tank 29, and the output shaft of the steam turbine 30 is shaft-connected with the generator 31. As Figure 2 shown, a heat conduction layer 35 is arranged between the water tank 27 and the annular honeycomb ceramic heat storage brick 34.

[0100] In this embodiment, the above burner supplements the heat required for lean gas catalytic oxidation by the heat generated from pulverized coal combustion to reduce the energy consumption of the lean gas catalytic oxidation reaction.

[0101] In this embodiment, the heat Q1, kJ required for preheating air in a commutation cycle is calculated through a thermodynamic calculation formula; Q1 = V air (C″ air t″ air -C' air t' air )×Z k , where V air represents the preheated air volume, m 3 / h; C″ air , C' air respectively represent the average specific heat capacities of the inlet and outlet air of the annular honeycomb ceramic heat storage brick 34, kJ / (m 3 ·℃); t″ air , t' air respectively represent the inlet and outlet temperatures of the air, °C; Z k represents the air commutation time, h;

[0102] In this embodiment, the heat Q1 required to preheat air in a commutation cycle is calculated by a thermodynamic calculation formula, in kJ; Q1 = V air (C″ air t″ air -C' air t' air )×Z k , where V air represents the preheated air volume, in m 3 / h; C″ air and C' air respectively represent the average specific heat capacity of air entering and leaving the annular honeycomb ceramic regenerator brick 34, in kJ / (m 3 ·℃); t″ air and t' air respectively represent the inlet and outlet temperatures of air, in °C; Z k represents the air commutation time, in h;

[0103] In this embodiment, the heat Q2 that can be generated by unit mass of pulverized coal is calculated, in kJ; Q2 = q coal-LHV ×m coal ; where q coal-LHV represents the lower calorific value of pulverized coal, in kJ / kg; m coal represents the mass of pulverized coal, in kg; to enable the pulverized coal to provide sufficient heat to the catalytic oxidation system, it is necessary to satisfy Q2≥Q1;

[0104] In this embodiment, the heat Q3 that can be generated by methane in the catalytic oxidation reaction is calculated, in kJ; where L represents the flow rate of the exhausted ventilation gas to be treated, in m 3 / h; represents the methane concentration in the exhausted ventilation gas, in vol.%; represents the lower calorific value of methane, in kJ / m 3 , generally taking 35.88×10 3 kJ / m 3 ; η represents the oxidation rate of methane, in %; therefore, the residual heat Q4 generated during the reaction, in kJ, satisfies Q4 = Q3+Q2-Q1;

[0105] In this embodiment, a water inlet 28 is provided on the water tank 27 of the above heat energy recovery and utilization system; the working principle of the above heat energy recovery and utilization system is to utilize the waste heat energy Q4 to heat and vaporize the water in the annular cylindrical water tank 27 outside the exhausted ventilation gas catalytic oxidation system to generate steam, and these steams enter the pipeline through the filter screen 32 and the blade 33 to drive the rotor group of the steam turbine 30 to rotate, and the rotor group then drives the generator to convert electrical energy for power generation;

[0106] In this embodiment, it is assumed that all the waste heat Q4 is absorbed by water and the water temperature rises from t0 to t1. Calculate the heat absorbed by water, Q5 = C w ρ w V w (t1 - t0), where Q5 represents the heat absorbed by water when the temperature rises from t0 to t1, kJ; t1 and t0 represent the temperature of water in the water tank after being heated by waste heat energy and the initial temperature of water, °C; C w is the specific heat capacity of water, taking 4.2 kJ / (kg·°C); ρ w represents the density of water, taking 1000 kg / m 3 ; V w represents the volume of water added to the water tank, m 3 ;

[0107] In this embodiment, the working efficiency of the annular cylindrical water tank is: η 水箱 = Q5 / Q4×100%, where η 水箱 represents the working efficiency of the annular cylindrical water tank, %;

[0108] In this embodiment, the internal power of the steam turbine is: P' 汽轮机 = D0(h0 - h nl )η' 汽轮机 / 3.6, where P' 汽轮机 represents the internal power of the steam turbine, kW; D0 represents the steam intake of the steam turbine, t / h; η' 汽轮机 represents the relative internal efficiency of the steam turbine, taking 83%; h0 represents the intake heat energy value of the steam turbine, taking 3305.04 kJ / kg; h nl represents the final heat energy value of the ideal process (isentropic process) of the steam turbine, taking 2104.1 kJ / kg;

[0109] In this embodiment, the shaft-end power of the steam turbine is: P″ 汽轮机 = P' 汽轮机 η″ 汽轮机 , where P″ 汽轮机 represents the shaft-end power of the steam turbine, kW; η″ 汽轮机 represents the mechanical efficiency of the steam turbine, taking 98.6%;

[0110] In this embodiment, the power generation efficiency of the steam turbine: η″′ 汽轮机 = η' 汽轮机 η″ 汽轮机 η 发电机 , where η” 汽 ' 轮机 represents the power generation efficiency of the steam turbine, %; η 发电机 represents the efficiency of the generator, taking 96%;

[0111] In this embodiment, the power of the waste heat generator: P 发电机 = P 发电机 η 发电机 , where P 发电机 represents the power of the waste heat generator, in kW;

[0112] In this embodiment, the steam output consumed for each 1 kW·h of electric energy produced: d = 1000D0 / P 发电机 , where d represents the steam consumption rate, in kg / kW·h;

[0113] In summary, a vitiated air gas catalytic oxidation system and burner proposed by this technical solution belong to the technical fields of vitiated air gas catalytic oxidation utilization and coal mine energy conservation and emission reduction; the annular honeycomb ceramic heat storage brick 34 therein can effectively increase the surface area of the carrier and enhance the heat storage capacity; the countercurrent gas path device can alternately heat the vitiated air gas, improve the conversion rate of the vitiated air gas, and realize the self-sustaining operation of the device; deduce a general formula for calculating the number of holes, which is applicable to any annular honeycomb ceramic heat storage brick 34 with square channels on the surface; use inexpensive pulverized coal as the raw material, provide air volume to the pulverized coal through a blower, and make the pulverized coal evenly distributed in the reaction pipeline in a suspended state; set a relatively low heating temperature, use the heat generated by the combustion of the pulverized coal to supply heat to the vitiated air gas catalytic oxidation system, effectively reduce the reaction energy consumption, and the released heat is used for the vitiated air gas catalytic oxidation system; calculate the heat generated by the pulverized coal combustion reaction, the heat generated by the vitiated air gas reaction, and the waste heat of the system reaction, and provide a heat calculation process for the complete reaction process; heat and vaporize the water in the water tank through the waste heat energy to generate steam, and then the steam drives the rotor group of the steam turbine to rotate through the filter screen and blades, and the rotor group then drives the generator to convert electrical energy for power generation. While fully catalytically oxidizing and utilizing the vitiated air gas, the energy utilization of the entire reaction system is realized, and the problems of large energy consumption, large heat loss, and low conversion efficiency in the process of vitiated air gas catalytic oxidation are overcome.

[0114] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0115] Specific examples are used in this article to elaborate on the principles and implementation methods of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A catalytic oxidation system for low-concentration methane, characterized in that, The diluted wind gas catalytic oxidation system includes: a catalytic reaction unit and a countercurrent gas path device; The countercurrent gas path device is connected to the catalytic reaction unit; The catalytic reaction unit includes annular honeycomb ceramic heat storage bricks, a pulverized coal combustion system is arranged inside the ring of the annular honeycomb ceramic heat storage bricks, and the annular honeycomb ceramic heat storage bricks are used to carry the catalyst.

2. The catalytic oxidation system for low-concentration methane in exhausted air according to claim 1, wherein The countercurrent gas path device includes an air compressor, a methane gas cylinder, a gas mixing tank, a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve and an annular pipeline; The first solenoid valve, the second solenoid valve, the third solenoid valve and the fourth solenoid valve are distributed on the annular pipeline; The air compressor and the methane gas cylinder are both connected to the inlet of the gas mixing tank, and the outlet of the gas mixing tank is connected to a first preset position on the annular pipeline; the first preset position is between the first solenoid valve and the second solenoid valve; A first port of the catalytic reaction unit is connected to a second preset position on the annular pipeline, a second port of the catalytic reaction unit is connected to a third preset position on the annular pipeline, the second preset position is between the first solenoid valve and the third solenoid valve, and the third preset position is between the second solenoid valve and the fourth solenoid valve; An air outlet is arranged at a fourth preset position on the annular pipeline, and the fourth preset position is between the third solenoid valve and the fourth solenoid valve.

3. The catalytic oxidation system for ventilation air methane according to claim 2, wherein The countercurrent wind gas inlet device further includes a temperature measuring device and a temperature data acquisition module, and the temperature measuring device includes a plurality of thermocouples; The plurality of thermocouples are evenly distributed inside the catalytic reaction unit; The temperature data acquisition module is connected to each thermocouple.

4. A dual-channel countercurrent flow inert gas combustion burner, characterized in that, The burner includes: a pulverized coal combustion system and the diluted wind gas catalytic oxidation system according to any one of claims 1-3; The pulverized coal combustion system is arranged inside the ring of the annular honeycomb ceramic heat storage bricks of the diluted wind gas catalytic oxidation system and is used to provide heat for the diluted wind gas catalytic oxidation system.

5. The exhausted air gas two-channel countercurrent burner according to claim 4, characterized in that, The pulverized coal combustion system includes a powder supply device, an annular heating device and a pulverized coal combustion chamber; the pulverized coal combustion chamber is a cylindrical reaction pipeline; The pulverized coal combustion chamber is arranged inside the ring of the heating device, and the heating device is arranged inside the ring of the annular honeycomb ceramic heat storage bricks; The powder supply device is communicated with the pulverized coal combustion chamber.

6. The exhausted air gas dual-channel countercurrent burner according to claim 5, characterized in that, The powder supply device includes a pulverized coal bin, a continuous powder feeder, a blower, a coke collection device and a filter cartridge; The continuous powder feeder and the blower are both communicated with the powder inlet of the pulverized coal combustion chamber, and the continuous powder feeder is also communicated with the pulverized coal bin; The coke collection device and the filter cartridge are both communicated with the powder outlet of the pulverized coal combustion chamber.

7. The exhausted mine gas dual-channel countercurrent burner according to claim 4, characterized in that, The burner further includes a heat energy recovery and utilization system; The heat energy recovery and utilization system includes a water tank, a steam turbine system and a generator; The diluted wind gas catalytic oxidation system is arranged inside the water tank, the steam turbine system is communicated with the steam outlet of the water tank, and the steam turbine system is shaft-connected to the generator.

8. The exhausted air gas two-channel countercurrent burner according to claim 7, characterized in that, The steam turbine system includes a water outlet tank, a filter screen, blades and a steam turbine; The water outlet tank is communicated with the steam outlet of the water tank, and the filter screen is arranged at the steam outlet of the water tank; The blade is located inside the water outlet tank. The blade is communicated with the steam turbine through a pipeline, and the output shaft of the steam turbine is connected to the generator shaft.

9. The exhausted mine gas dual-channel countercurrent burner according to claim 5, characterized in that, A first gas detection port, a second gas detection port, and a third gas detection port are provided above the burner. The first gas detection port is located at the outlet of the gas mixing tank of the exhausted gas catalytic oxidation system. The second gas detection port is located at the gas outlet provided on the annular pipeline of the exhausted gas catalytic oxidation system. The third gas detection port is located at the gas outlet of the filter cartridge of the pulverized coal combustion system. The first gas detection port, the second gas detection port, and the third gas detection port are all used to connect an on-line methane analyzer.

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