Combustible gas tail gas treatment system and method

Abstract

The present invention relates to the technical field of waste gas treatment, and discloses a system and method for treating combustible gas exhaust. The system includes a tail gas preheater, a start-up heater, and a combustible gas reaction unit that are sequentially connected along the flow direction of the combustible gas exhaust, wherein the combustible gas reaction unit includes a reaction device, and an explosion-suppressing quenching filler layer is provided at one end near the bottom of the reaction device. A gas distributor and an explosion-proof and explosion-suppressing filler layer are sequentially provided on the upper part of the explosion-proof and explosion-suppressing filler layer from bottom to top, and a plurality of catalyst beds and explosion-suppressing quenching filler layers are alternately provided on the upper part of the explosion-proof and explosion-suppressing filler layer from bottom to top. The system provided by the present invention enables combustible gas and oxygen to undergo a gas-solid phase catalytic reaction within the explosion limit, thereby improving the selectivity and conversion rate of the oxidation process and increasing the removal rate of combustible gas.

Description

Technical Field

[0001] The present invention relates to the technical field of waste gas treatment, and in particular to a system and method for treating combustible gas. Background Art

[0002] Carbon monoxide (CO) is a colorless, odorless, toxic gas that generally originates from incomplete combustion or partial oxidation of coal, gasoline, and natural gas. CO has a strong binding affinity with hemoglobin and is therefore highly toxic. At higher concentrations, CO can cause varying degrees of poisoning in humans, harming the brain, heart, liver, kidneys, lungs, and other tissues, and even causing death by electric shock. The minimum lethal concentration for inhalation is 5000 ppm (5 minutes). Therefore, in the production process of petrochemical products, strict requirements should be made for the emission content of CO in tail gases. With increasingly stringent environmental protection requirements, Beijing, Zibo, and other regions have already implemented strict restrictions on the CO concentration in tail gases from chemical plants.

[0003] Currently, there are two main types of technologies for treating CO-containing tail gas: recovery and destruction. Recovery technologies involve enriching and separating CO through physical methods, such as changing temperature or pressure or using selective adsorbents and selective permeable membranes. These technologies primarily include adsorption, absorption, cryogenic separation, and membrane separation. Destruction technologies primarily use chemical or biochemical reactions, using heat, light, catalysts, and microorganisms to convert organic compounds into non-toxic or low-toxic inorganic small molecules such as carbon dioxide. These technologies primarily include direct combustion, catalytic combustion, biooxidation, photocatalytic oxidation, and plasma conversion. Recovery technologies primarily target gases with high concentrations or high economic value, while destruction technologies are primarily used when recovery technologies fail to meet environmental protection requirements or when recovery costs are high.

[0004] In some chemical production processes, the tail gas contains a high concentration of CO gas (volume content>3%). For this type of tail gas, the use of recovery technology to treat it has disadvantages such as high cost and complicated processes. The use of destruction technology to treat it is prone to safety and production accidents such as reactor overheating and catalyst damage. At the same time, when the CO and organic matter content in the tail gas is high, the synergistic effect of each component may cause an explosion accident in the reactor, posing a serious safety hazard. For example, when a company used thermal storage catalytic oxidation technology to treat tail gas, an explosion occurred due to fluctuations in the combustible content in the tail gas. Therefore, how to prevent the reactor from overheating when treating high-concentration combustible gases and eliminate the risk of explosion in the gas-solid phase combustible system has become a difficult problem that urgently needs to be solved in order to improve the quality and efficiency of the chemical industry in my country and even the world.

[0005] Patent application CN110013764A discloses an ionic liquid phase-change thermal storage catalytic oxidation device, comprising a gas mixer, a flame arrester, a catalytic oxidation reactor, a phase-change thermal storage device, and an exhaust gas treatment device. Its technical features include providing a novel ionic liquid phase-change thermal storage catalytic oxidation device with the advantages of constant temperature during the thermal storage and release process, high thermal storage density, and excellent safety. This patent utilizes a novel thermal storage element, addressing the issues of large temperature fluctuations and low thermal storage density during the thermal storage and release process in the prior art. However, it does not address the issues of reactor overheating and gas-phase explosions within the reactor caused by high combustible concentrations.

[0006] Patent application CN1903415A discloses a catalytic oxidation process for treating tail gas from an acrylonitrile plant's absorber. The primary technical problem addressed is a simple, low-resistance, no-boost-fan, no-auxiliary-fuel requirement, low-cost operation, no secondary pollution, and thorough tail gas treatment. However, the patent does not address the issues of reactor overheating and gas-phase explosions within the reactor caused by high combustible concentrations.

[0007] Patent application CN105066148A discloses a method for treating VOCs using low-temperature regenerative catalytic oxidation. This method, used in treating VOCs, offers advantages such as minimal safety hazards, a low ignition temperature, and low energy consumption. While this patent primarily reduces the reactor ignition temperature, addressing energy consumption, it does not address the issues of reactor overheating and gas-phase explosions caused by high combustible concentrations. Summary of the Invention

[0008] The present invention aims to overcome the inability of existing combustible gas treatment devices to effectively address reactor overheating and gas-phase explosions within the reactor caused by high combustible concentrations. The system provides a combustible gas tail gas treatment system and method. This system enables a gas-solid phase catalytic reaction between combustible gas and oxygen within explosion limits, improving the selectivity and conversion rate of the oxidation process and increasing the combustible gas removal rate.

[0009] In order to achieve the above-mentioned objectives, the present invention provides a combustible gas exhaust treatment system on the one hand, wherein the system includes an exhaust gas preheater, a start-up heater and a combustible gas reaction unit which are connected in sequence along the flow direction of the combustible gas exhaust, wherein the combustible gas reaction unit includes a reaction device, and an explosion-suppressing quenching filler layer is provided at one end near the bottom of the reaction device, and a gas distributor and an explosion-proof and explosion-suppressing filler layer are provided on the upper part of the explosion-proof and explosion-suppressing filler layer in sequence from bottom to top, and a plurality of catalyst beds and explosion-suppressing quenching filler layers are alternately provided on the upper part of the explosion-proof and explosion-suppressing filler layer in sequence from bottom to top.

[0010] Preferably, the explosion suppression and quenching filler layer comprises a plurality of corrugated plates stacked in a direction parallel to the axial direction of the reaction device, and a plurality of through holes are formed on the plate body of each of the corrugated plates for quenching the flame generated by the reaction raw materials.

[0011] Preferably, the height d1 of the catalyst bed, the height d2 of the explosion suppression and quenching packing layer, the distance d3 between two adjacent corrugated plates, the thickness δ of each corrugated plate, and the inner diameter R of the reaction device satisfy the following relationship:

[0012] d2=(m / 16)×22.963×10 3 ×d3 2 ×d1×M÷R 2

[0013] Where M is the relative molecular mass of the combustible gas.

[0014] Preferably, each catalyst bed comprises a plurality of reactors.

[0015] Preferably, each reactor is provided with a cooling jacket for containing cooling water.

[0016] Preferably, the height d1 of each catalyst bed is 0.2 to 3 m, preferably 0.3 to 2.5 m.

[0017] Preferably, the height d2 of the explosion suppression and quenching filler layer is 0.02 to 1.5 m, preferably 0.03 to 1 m.

[0018] Preferably, the spacing d3 between two adjacent corrugated plates (111) is 0.05 to 0.5 mm, preferably 0.1 to 0.3 mm.

[0019] Preferably, the thickness δ of each corrugated plate (111) is 0.1 to 2 mm, preferably 0.3 to 1.8 mm.

[0020] Preferably, the explosion-proof and explosion-suppressing filler in the explosion-proof and explosion-suppressing filler layer is a porous spherical non-metallic organic material.

[0021] Preferably, the inner diameter R of the reaction device is 0.2 to 3.5 m, preferably 0.4 to 3 m.

[0022] Preferably, the gas distributor comprises a coil and gas nozzles arranged at equal intervals on the coil.

[0023] Preferably, the combustible gas reaction unit further comprises a cooling water supply unit and a cooling water feed pipeline, and the cooling water from the cooling water supply unit enters the cooling jacket outside each reactor of the catalyst bed through the cooling water feed pipeline.

[0024] Preferably, a cooling water feed regulating valve is provided between the cooling water supply unit and the cooling water feed pipeline, and a cooling water flow meter is provided between the cooling water feed regulating valve and the catalyst bed.

[0025] Preferably, the combustible gas reaction unit further includes a steam generator and a cooling water discharge pipeline, and the cooling water from the cooling water supply unit enters the steam generator through the cooling water discharge pipeline after heat exchange in the cooling jacket.

[0026] Preferably, the combustible gas reaction unit further comprises a liquid level meter for monitoring the liquid level of water in the steam generator.

[0027] Preferably, the combustible gas reaction unit further includes a pressure gauge and a thermometer, which are used to monitor the pressure and temperature of the steam generator respectively.

[0028] Preferably, the system further comprises a flame arrester, which is arranged before the exhaust gas preheater along the flow direction of the combustible exhaust gas;

[0029] Preferably, the system further comprises an online combustible gas monitor, which is arranged between the flame arrester and the exhaust gas preheater.

[0030] Preferably, the bottom of the reaction device is provided with a combustible gas inlet, and the combustible gas tail gas from the start-up heater enters the reaction device through the combustible gas inlet.

[0031] Preferably, the top of the reaction device is provided with a combustible gas outlet, and the combustible gas outlet is connected to the tail gas preheater.

[0032] Preferably, the reaction device has an air inlet at one end close to the bottom for introducing air into the reaction device.

[0033] A second aspect of the present invention provides a method for treating combustible gas, which is implemented in the system described above and comprises the following steps:

[0034] The combustible gas tail gas is sequentially introduced into the tail gas preheater and the start-up heater for heating, and then the heated combustible gas tail gas and air are introduced into the combustible gas reaction unit for catalytic oxidation reaction.

[0035] Preferably, the volume flow ratio of the combustible gas to air is 10-30, preferably 12-25.

[0036] Preferably, the conditions for the catalytic oxidation reaction include: a temperature of 150-250°C.

[0037] The combustible gas reaction unit in the combustible gas exhaust treatment system described in the present invention is equipped with an isothermal explosion-proof and explosion-suppressed reaction device. By dividing the catalyst bed in the reaction device into multiple layers and arranging them at intervals along the flow direction of the reaction raw materials, the intensity of the gas-solid phase catalytic reaction in the catalyst bed is directly reduced, thereby avoiding the release of excessive heat to cause the combustible gas in the reaction raw materials to explode; and by arranging an explosion-suppressing quenching filler layer on the upper part of each catalyst bed, that is, on the discharge side of each catalyst bed, the explosion-suppressing quenching filler layer is used to quench the flame generated by the reaction raw materials, so that the combustible gas and oxygen can undergo a gas-solid phase catalytic reaction within the explosion limit, thereby improving the selectivity and conversion rate of the oxidation process and improving the removal rate of the combustible gas.

[0038] Under preferred conditions, on the one hand, the reaction device of the present invention adopts a special feeding method to mix the materials and then enter the catalyst bed through the explosion suppression quenching filler, and proposes a structure-activity relationship between the diameter and height of the explosion suppression quenching filler and the catalyst bed height and the reactor diameter, thereby ensuring that carbon monoxide can undergo catalytic oxidation reaction within the explosion limit. On the second hand, the combustible gas reaction unit of the present invention is provided with a steam generator, which not only prevents the reaction device from overheating and damaging the catalyst, but also effectively recovers the heat generated by the device and reduces the energy consumption of the device. The reaction device can ensure the safety of the catalytic oxidation reaction of combustible gas and oxygen within its explosion limit, can reduce the use of stabilizing gas or inert gas, improve the selectivity and conversion rate of the oxidation process, and improve the removal rate of combustible gas. On the third hand, the reactor is provided with a cooling jacket and a steam generator, which can not only protect the catalyst bed from overheating due to high carbon monoxide concentration and damage to the catalyst and reactor, but also effectively recover the heat generated by the catalytic oxidation reaction, ensuring the safe, stable and efficient operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic diagram of the combustible gas tail gas treatment system of the present invention;

[0040] Figure 2 is a schematic diagram of the combustible gas reaction unit of the present invention;

[0041] Figure 3 This is a top view of the explosion suppression and quenching filler layer of the present invention;

[0042] Figure 4 1 is a top view of the gas distributor according to the present invention.

[0043] Description of Reference Numerals

[0044] 1. Reaction unit; 2. Tail gas preheater; 3. Start-up heater; 4. Flame arrester; 5. Online combustible gas monitor; 6. Combustible gas inlet; 7. Combustible gas tail gas outlet; 8. Air inlet; 11. Explosion suppression and quenching packing layer; 12. Gas distributor; 13. Explosion-proof and explosion suppression packing layer; 14. Catalyst bed; 15. Cooling water feed pipeline; 16. Cooling water feed regulating valve; 17. Cooling water flow meter; 18. Steam generator; 19. Cooling water discharge pipeline; 101. Tail gas discharge pipeline; 111. Corrugated plate; 121. Coil; 122. Gas nozzle; 141. Reactor; 142. Cooling jacket; 181. Liquid level gauge; 182. Pressure gauge; 183. Thermometer; 184. Steam pipeline; 185. Pressure regulating valve. DETAILED DESCRIPTION

[0045] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0046] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0047] The first aspect of the present invention provides a combustible gas treatment system, such as Figure 1 As shown, the system includes a tail gas preheater 2, a startup heater 3, and a combustible gas reaction unit, which are sequentially connected along the flow direction of the combustible gas. In the present invention, the combustible gas is first preheated by the tail gas preheater 2. The startup heater 3 then heats the combustible gas to the reaction temperature of the catalyst loaded in the reaction device 1 of the combustible gas reaction unit. The heated combustible gas is then passed into the reaction device 1 of the combustible gas reaction unit for a catalytic oxidation reaction.

[0048] According to the present invention, Figure 2 As shown, the combustible gas reaction unit includes a reaction device 1, and an explosion-suppressing and quenching packing layer 11 is provided at one end near the bottom of the reaction device 1. A gas distributor 12 and an explosion-proof and explosion-suppressing packing layer 13 are provided on the upper part of the explosion-proof and explosion-suppressing packing layer 11 in sequence from bottom to top. A plurality of catalyst beds 14 and explosion-suppressing and quenching packing layers 11 are provided on the upper part of the explosion-proof and explosion-suppressing packing layer 13 in sequence from bottom to top.

[0049] In the combustible gas reaction unit in the combustible gas exhaust treatment system described in the present invention, the catalyst bed 14 in the reaction device 1 is divided into multiple layers and spaced apart along the flow direction of the reaction raw materials, thereby directly reducing the intensity of the gas-solid phase catalytic reaction in the catalyst bed 14, thereby avoiding the release of excessive heat to cause the combustible gas in the reaction raw materials to explode; and by arranging an explosion-suppressing quenching filler layer 11 on the upper part of each catalyst bed 14, that is, on the discharge side of each catalyst bed 14, the explosion-suppressing quenching filler layer 11 is used to quench the flame generated by the reaction raw materials, so that the combustible gas and oxygen can undergo a gas-solid phase catalytic reaction within the explosion limit, thereby improving the selectivity and conversion rate of the oxidation process and improving the removal rate of the combustible gas.

[0050] In the present invention, the function of the explosion suppression and quenching filler layer 11 is to prevent the continuous propagation of the flame in the catalyst bed 14. Even if the combustible gas and oxygen explode within the explosion limit, the explosion suppression and quenching filler layer 11 can still quench the flame, thereby allowing the combustible gas to undergo gas-solid phase catalytic reaction under high concentration conditions, breaking through the bottleneck of low reaction efficiency and inability to achieve large-scale production of the existing green process route, and providing an inherently safe solution for the gas-solid phase catalytic reaction process with a higher risk of explosion.

[0051] In a specific embodiment, Figure 3 As shown, the explosion-suppression and quenching packing layer 11 comprises multiple corrugated plates 111 stacked parallel to the axial direction of the reaction apparatus 1. Each corrugated plate 111 has multiple through-holes for quenching the flames generated by the reaction raw materials. Furthermore, the explosion-suppression and quenching packing layer 11 includes a packing ring for securing the stacked corrugated plates 111, forming a certain height of the explosion-suppression and quenching packing layer 11.

[0052] Furthermore, the through holes provided in the corrugated plate 111 can redirect the airflow, preventing the flame from propagating and quenching the flame. The through holes can be of various shapes, such as circular, triangular, square, or rectangular, with rectangular holes being preferred. The multiple through holes can be of the same shape or of different shapes.

[0053] According to the present invention, the material of the corrugated plate 111 needs to be specifically selected based on the reaction raw materials of the reaction apparatus 1. For example, if the reaction raw materials contain acidic gas, a material resistant to acid corrosion, such as an aluminosilicate acid-resistant and chemical-resistant ceramic material, needs to be selected. Furthermore, the reaction apparatus 1 can be a reactor in which a gas-phase catalytic reaction is carried out under the catalytic action of a solid-phase catalyst.

[0054] In the present invention, by alternately installing multiple catalyst beds 14 and multiple explosion suppression and quenching filler layers 11 in the reaction device 1, the heat generated by the gas-solid phase catalytic reaction can be reduced, and the flame generated by the reaction raw materials can be quenched, so that the catalytic oxidation reaction of air (or oxygen) and combustible gas can operate within the explosion limit, thereby increasing its oxidation efficiency.

[0055] The combustible gas reaction unit of the present invention is used for catalytic oxidation reaction of combustible gas, and the combustible gas includes but is not limited to carbon monoxide, and the combustible gas can also be methane, ethane and propane. In the present invention, the inventor proposed a structure-activity relationship between the distance d3 between two adjacent corrugated plates 111 in the explosion suppression and quenching packing layer 11, the height d2 of the explosion suppression and quenching packing layer 11 and the height d1 of the catalyst bed 14, and the inner diameter R of the reaction device 1 based on the quenching distance between the combustible gas flame in the explosion suppression and quenching packing layer 11 and the height d1 of the catalyst bed 14, so as to design a matching form between different types of explosion suppression and quenching packing layers 11 and the height of the catalyst bed 14, so that the combustible gas content can be catalytically oxidized within the explosion limit. The main reason is that even if the combustible gas, especially carbon monoxide, ignites in the catalyst bed due to static electricity or abnormal working conditions, the special packing structure and catalyst bed design can quench the flame, thereby preventing the combustible gas from exploding in the reactor. At the same time, the catalytic oxidation reaction of the combustible gas with this structure can improve the selectivity and conversion rate of the combustible gas, especially carbon monoxide, and improve the removal rate of carbon monoxide.

[0056] Specifically, the height d1 of the catalyst bed 14, the height d2 of the explosion suppression and quenching packing layer 11, the spacing d3 between two adjacent corrugated plates 111, the thickness δ of each corrugated plate 111, and the inner diameter R of the reaction device 1 satisfy the following relationship:

[0057] Where M is the relative molecular mass of the combustible gas.

[0058] In the combustible gas reaction unit, combustible gas exhaust and air are introduced from the bottom of the reaction device 1, and the combustible gas exhaust and air (or oxygen) move from bottom to top, passing through the explosion suppression and quenching packing layer 11, the gas distributor 12 and the explosion-proof and explosion suppression packing layer 13 in sequence, and then react in multiple catalyst beds 14. The exhaust gas after the catalytic reaction is completed flows out from the exhaust gas discharge pipeline 101 connected to the top of the reaction device 1. In the present invention, an explosion suppression and quenching packing layer 11 is provided at one end of the reaction device 1 near the bottom, at one end of the reaction device 1 near the top, and between the two catalyst beds 14, which can quickly quench the flame at any part of the reaction device 1, thereby preventing the combustible gas from exploding in the reactor.

[0059] In the present invention, the exhaust gas preheater 2 can be a common heating device in the art, as long as it can preheat the exhaust gas; similarly, the start-up heater 3 can be a common heating device in the art, as long as it can heat the exhaust gas.

[0060] In the combustible gas reaction unit of the present invention, the number of the catalyst bed 14 and the explosion suppression and quenching filler layer 11 in the reaction device 1 is determined according to the size of the reaction device.

[0061] In a preferred embodiment, 2 to 15 catalyst beds 14 and explosion suppression and quenching packing layers 11 are alternately arranged in sequence from bottom to top on the upper part of the explosion-proof and explosion-suppressing packing layer 13. In a more preferred embodiment, 3 to 10 catalyst beds 14 and explosion suppression and quenching packing layers 11 are alternately arranged in sequence from bottom to top on the upper part of the explosion-proof and explosion-suppressing packing layer 13. When 3 catalyst beds 14 and explosion suppression and quenching packing layers 11 are alternately arranged in sequence from bottom to top on the upper part of the explosion-proof and explosion-suppressing packing layer 13, a catalyst bed 14, an explosion suppression and quenching packing layer 11, a catalyst bed 14, an explosion suppression and quenching packing layer 11, a catalyst bed 14, and an explosion suppression and quenching packing layer 11 are arranged in sequence on the upper part of the explosion-proof and explosion-suppressing packing layer 13. That is, an explosion suppression and quenching packing layer 11 is arranged between two catalyst beds 14, and finally an explosion suppression and quenching packing layer 11 is arranged at one end of the reaction device 1 near the top.

[0062] In the method of the present invention, the number of reactors 141 contained in each catalyst bed 14 can be determined according to the size of the catalyst bed 14. In a preferred embodiment, each catalyst bed 14 includes 9 to 30 reactors 141. In a more preferred embodiment, each catalyst bed 14 includes 12 to 24 reactors 141.

[0063] The arrangement of the multiple reactors 141 in the catalyst bed 14 is not limited and can be arranged according to conventional methods in the art. In a specific embodiment, each catalyst bed 14 includes multiple reactors 141. Preferably, each catalyst bed 14 includes 18 reactors 141, and the 18 reactors 141 are arranged in 6 rows at equal intervals, with 3 reactors 141 stacked in each row.

[0064] In some embodiments, the explosion suppression and quenching filler layer 11 is arranged to be spaced apart from the adjacent catalyst bed layer 14. Figure 2As shown, a plurality of catalyst beds 14 arranged at intervals are provided in the reaction device 1. After the reaction raw materials pass through a layer of catalyst bed 14 and react under the catalytic action of the catalyst, the reaction raw materials are still uneven in the radial direction of the reaction device 1. By setting a spacing between the explosion suppression and quenching filler layer 11 and the adjacent catalyst bed 14, the reaction raw materials are further mixed in the spacing, which makes the reaction raw materials tend to be uniform when entering the next layer of catalyst bed 14, thereby improving the uniformity of the gas-solid phase catalytic reaction.

[0065] In a preferred embodiment, each reactor 141 is provided with a cooling jacket 142 for containing cooling water. Cooling water is passed through the cooling jacket 142 to prevent overheating of the catalyst bed 14 due to high concentrations of combustible gas, which could damage the catalyst and reactor. The circulating cooling water also ensures that the combustible gas maintains a constant temperature within the catalyst bed 14 for the catalytic reaction.

[0066] In a specific embodiment, Figure 1 As shown, the combustible gas reaction unit further includes a cooling water supply unit and a cooling water feed pipeline 15. The cooling water from the cooling water supply unit enters the cooling jacket 142 outside each reactor 141 of the catalyst bed 14 through the cooling water feed pipeline 15. In a preferred embodiment, each catalyst bed 14 can correspond to a cooling water feed pipeline 15. Specifically, a main pipeline can be set from the output end of the cooling water supply unit, and then divided from the main pipeline into multiple cooling water feed pipelines 15. The multiple cooling water feed pipelines 15 are respectively connected to the multiple catalyst beds 14 to transport cooling water to the cooling jacket 142 in each catalyst bed 14. The source of the cooling water is not limited. It can be pure water or boiler water generated in other process processes, as long as it can achieve a cooling effect.

[0067] In the combustible gas reaction unit of the present invention, if Figure 1 As shown, preferably, a cooling water feed regulating valve 16 is provided between the cooling water supply unit and the cooling water feed pipeline 15. The cooling water feed regulating valve 16 is used to regulate the amount of cooling water entering the catalyst bed 14, thereby ensuring that the catalytic deoxygenation reaction in the catalyst bed 14 can proceed at a constant temperature. More preferably, a cooling water feed regulating valve 16 can be provided on each cooling water feed pipeline 15 to independently control the amount of cooling water entering each catalyst bed 14.

[0068] Preferably, a cooling water flow meter 17 is provided between the cooling water feed regulating valve 16 and the catalyst bed 14. In order to individually monitor the amount of cooling water flowing into each catalyst bed 14, a cooling water flow meter 17 may be provided on each cooling water feed pipeline 15.

[0069] In the combustible gas reaction unit of the present invention, the height d1 of the catalyst bed 14, the height d2 of the explosion suppression and quenching packing layer 11, the spacing d3 between two adjacent corrugated plates 111, and the inner diameter R of the reaction device 1 are set according to the actual size and type of the reaction device 1, as long as the aforementioned relationship is satisfied.

[0070] Specifically, the height d1 of each catalyst bed 14 may be 0.2 to 3 m, preferably 0.3 to 2.5 m.

[0071] Specifically, the height d2 of the explosion suppression and quenching filler layer 11 may be 0.02 to 1.5 m, preferably 0.03 to 1 m.

[0072] In a specific embodiment, Figure 3 As shown, the distance d3 between two adjacent corrugated plates 111 is 0.05-0.5 mm, preferably 0.1-0.3 mm.

[0073] In a specific embodiment, the thickness δ of each corrugated plate 111 is 0.1-2 mm, preferably 0.3-1.8 mm.

[0074] In the combustible gas reaction unit of the present invention, the explosion-proof and explosion-suppressing filler layer 13 can be a conventional option commonly used in the art. The explosion-proof and explosion-suppressing filler layer 13 not only serves to prevent fire and explosion, but also promotes a more uniform distribution of the reaction materials entering the first catalyst bed 14 in the radial direction of the reaction device 1, thereby improving the uniformity of the gas-solid phase catalytic reaction, avoiding the generation of local hot spots in the catalyst bed 14, and reducing the risk of explosion.

[0075] In a preferred embodiment, the explosion-proof and explosion-suppressing filler in the explosion-proof and explosion-suppressing filler layer 13 is a porous spherical non-metallic organic material.

[0076] In the combustible gas reaction unit of the present invention, specifically, the reaction device 1 is divided into a top, a middle and a bottom, and the explosion suppression and quenching filler layer 11, the gas distributor 12, the explosion-proof and explosion suppression filler layer 13 and the catalyst bed 14 are all arranged in the middle of the reaction device 1.

[0077] Preferably, the middle portion of the reaction device 1 is cylindrical, and the inner diameter R of the reaction device 1 is 0.2 to 3.5 m, preferably 0.4 to 3 m.

[0078] In the combustible gas reaction unit of the present invention, if Figure 4As shown, the gas distributor 12 includes a coil 121 and gas nozzles 122 provided on the coil 121. In order to allow the combustible gas and oxygen to enter the explosion-proof and explosion-suppressing filler layer 13 and the catalyst bed 14 evenly and smoothly, the gas nozzles 122 are arranged on the coil 121 at equal intervals.

[0079] In the present invention, the combustible gas reaction unit further includes a steam generator 18 and a cooling water discharge pipeline 19. The cooling water from the cooling water supply unit undergoes heat exchange in the cooling jacket 142 and then enters the steam generator 18 through the cooling water discharge pipeline 19. The hot water obtained after the cooling water from the cooling water supply unit undergoes heat exchange in the cooling jacket 142 enters the steam generator 18 through the cooling water discharge pipeline 19 for evaporation. The obtained water vapor can be passed through a steam pipeline to other process operations for reuse, effectively recovering the heat generated by the catalytic oxidation reaction. At the same time, the hot water obtained by heat exchange is removed from the catalyst bed 14 through the cooling water discharge pipeline 19, thereby removing the heat in the catalyst bed 14, allowing the catalyst bed 14 to operate at a constant temperature, preventing the catalyst bed from overheating due to excessively high combustible gas concentration, which could damage the catalyst and reactor, and also avoiding abnormal operating conditions such as excessively high temperatures that could cause the catalyst bed to ignite.

[0080] In the present invention, preferably, the combustible gas reaction unit further includes a liquid level meter 181, and the liquid level meter 181 is electrically connected to the control device so that the control device can control the opening of the cooling water feed regulating valve 16 according to the liquid level height signal of the steam generator 18 monitored by the liquid level meter 181.

[0081] In the present invention, the combustible gas reaction unit preferably further includes a pressure gauge 182 and a thermometer 183. The pressure regulating valve 185 and the pressure gauge 182 are both electrically connected to a DCS control device to form an interlocking control. The DCS control device is configured to control the opening of the pressure regulating valve 185 based on the pressure signal from the steam generator 18 monitored by the pressure gauge 182. During operation, the pressure within the steam generator 18 is monitored in real time via the pressure gauge 182, and the opening of the pressure regulating valve 185 is adjusted and controlled based on feedback, allowing the steam generated within the steam generator 18 to be discharged in a timely manner, thereby ensuring safe operation of the steam generator 18. The thermometer 183 is used to detect the real-time temperature within the steam generator 18.

[0082] In a specific embodiment, the steam generator 18 has a steam outlet at the top, which is connected to a steam pipeline 184. The steam pipeline 184 is used to discharge the steam generated by the steam generator 18 for reuse. Preferably, a pressure regulating valve 185 is provided on the steam pipeline 184 to regulate the pressure in the steam generator 18.

[0083] In a specific embodiment, the system further includes a flame arrester 4, which is arranged before the exhaust gas preheater 2 along the flow direction of the combustible gas. When the combustible gas flame generated in the reaction device 1 propagates in the opposite direction of the flow direction of the combustible gas, the flame arrester 4 prevents the flame from further spreading.

[0084] In a preferred embodiment, the system further comprises an online combustible gas monitor 5, which is disposed between the flame arrester 4 and the tail gas preheater 2. The online combustible gas monitor 5 can monitor the concentration and content of the combustible gas in the tail gas online.

[0085] In the combustible gas exhaust treatment system of the present invention, preferably, the bottom of the reaction device 1 is provided with a combustible gas inlet 6, and the combustible gas exhaust from the start-up heater 3 enters the reaction device 1 through the combustible gas inlet 6. In the combustible gas exhaust treatment system of the present invention, preferably, the top of the reaction device 1 is provided with a combustible gas exhaust outlet 7, and the combustible gas exhaust outlet 7 is connected to the exhaust gas preheater 2. After the combustible gas exhaust reacts in the reaction device 1, the obtained high-temperature combustible gas exhaust flows out from the combustible gas exhaust outlet 7 and enters the exhaust gas preheater 2. The high-temperature combustible gas exhaust can be heat-exchanged with the newly introduced combustible gas exhaust, thereby recycling the heat in the high-temperature combustible gas exhaust after the reaction, saving energy consumption, and finally the treated exhaust gas is discharged from the chimney.

[0086] In a preferred embodiment, Figure 1 As shown, the reaction device 1 has an air inlet 8 at one end near the bottom for introducing air into the reaction device 1. After the air enters the reaction device 1, it contacts the combustible gas entering the reaction device 1. The combustible gas and oxygen in the air undergo a catalytic oxidation reaction in the catalyst bed 14. The air can be blown into the reaction device 1 by an air blower.

[0087] A second aspect of the present invention provides a method for treating combustible gas, which is implemented in the system described above and comprises the following steps:

[0088] The combustible gas is sequentially introduced into the tail gas preheater 2 and the start-up heater 3 for heating, and then the heated combustible gas and air are introduced into the combustible gas reaction unit for catalytic oxidation reaction.

[0089] In the method of the present invention, specifically, during the catalytic oxidation reaction of the combustible gas and air in the combustible gas reaction unit, the reactor 141 is continuously cooled by cooling water in the catalyst bed 14, so that the catalytic oxidation reaction is carried out at a constant temperature. The hot water obtained after the heat exchange of the cooling water enters the steam generator 18, effectively recovering the heat of the reaction device 1.

[0090] Preferably, the volume flow ratio of the combustible gas to air may be 10-30, preferably 12-25.

[0091] In the method of the present invention, the conditions for the catalytic oxidation reaction include: a temperature of 150 to 250° C. In the present invention, the catalyst used in the catalytic oxidation reaction can be a conventional catalyst in the art, for example, the catalyst carrier is honeycomb Al2O3, and the active component is Pd, Au or Ag.

[0092] The present invention will be described in detail below through examples, but the scope of protection of the present invention is not limited thereto. In the following examples, the combustible gas refers to carbon monoxide, and its relative molecular mass M is 28.

[0093] The following examples are implemented in a combustible gas tail gas treatment system, such as Figure 1-4As shown, the system includes a tail gas preheater 2, a start-up heater 3 and a combustible gas reaction unit which are connected in sequence along the flow direction of the combustible gas tail gas, wherein the combustible gas reaction unit includes a reaction device 1, and an explosion suppression quenching packing layer 11 is provided at one end near the bottom of the reaction device 1, and a gas distributor 12 and an explosion-proof and explosion-suppressing packing layer 13 are provided on the upper part of the explosion-proof and explosion-suppressing packing layer 11 in sequence from bottom to top, and a plurality of catalyst beds 14 and explosion suppression quenching packing layers 11 are alternately provided on the upper part of the explosion-proof and explosion-suppressing packing layer 13 in sequence from bottom to top, and the explosion suppression quenching packing layer 11 includes a plurality of corrugated plates 111 stacked in a direction parallel to the axial direction of the reaction device 1, and a plurality of through holes are opened on the plate body of each of the corrugated plates 111 to Used to quench the flame generated by the reaction raw materials, each catalyst bed 14 includes a plurality of reactors 141, each reactor 141 is provided with a cooling jacket (142) for accommodating cooling water, the catalyst carrier filled in the reactor 141 is a honeycomb Al2O3, the active component is Ag, the explosion-proof and explosion-suppressing filler in the explosion-proof and explosion-suppressing filler layer 13 is a porous spherical non-metallic organic material, the gas distributor 12 includes a coil 121 and gas nozzles 122 arranged at equal intervals on the coil 121, the combustible gas reaction unit also includes a cooling water supply unit and a cooling water feed pipeline 15, the cooling water from the cooling water supply unit enters each reaction of the catalyst bed 14 through the cooling water feed pipeline 15 In the cooling jacket 142 outside the reactor 141, a cooling water feed regulating valve 16 is provided between the cooling water supply unit and the cooling water feed pipeline 15, and a cooling water flow meter 17 is provided between the cooling water feed regulating valve 16 and the catalyst bed 14. The combustible gas reaction unit also includes a steam generator 18 and a cooling water discharge pipeline 19. The cooling water from the cooling water supply unit enters the steam generator 18 through the cooling water discharge pipeline 19 after heat exchange in the cooling jacket 142. The combustible gas reaction unit also includes a liquid level meter 181 for monitoring the liquid level of water in the steam generator 18; the combustible gas reaction unit also includes a pressure gauge 182 and a thermometer 183, respectively for monitoring The pressure and temperature of the steam generator 18 are measured. The system also includes a flame arrester 4. Along the flow direction of the combustible gas, the flame arrester 4 is arranged before the exhaust gas preheater 2. The system also includes an online combustible gas monitor 5. The online combustible gas monitor 5 is arranged between the flame arrester 4 and the exhaust gas preheater 2. The bottom of the reaction device 1 has a combustible gas inlet 6. The combustible gas exhaust from the start-up heater 3 enters the reaction device 1 through the combustible gas inlet 6. The top of the reaction device 1 has a combustible gas outlet 7. The combustible gas outlet 7 is connected to the exhaust gas preheater 2. The end of the reaction device 1 near the bottom has an air inlet 8 for introducing air into the reaction device 1.

[0094] Example Group 1

[0095] In this experimental group, the height d1 of the catalyst bed 14, the height d2 of the explosion suppression quenching packing layer 11, the spacing d3 between two adjacent corrugated plates 111, the thickness M of each corrugated plate 111, and the inner diameter R of the reaction device 1 are set as shown in Table 1. The height d1 of the catalyst bed 14, the height d2 of the explosion suppression quenching packing layer 11, the spacing d3 between two adjacent corrugated plates 111, the thickness δ of each corrugated plate 111, and the inner diameter R of the reaction device 1 satisfy the following relationship:

[0096]

[0097] Combustible gas tail gas treatment methods include:

[0098] The flow rate is 12000Nm 3 / h of combustible gas exhaust is sequentially introduced into the exhaust gas preheater 2 and the start-up heater 3 for heating, and then the heated combustible gas exhaust is mixed with a flow rate of 500Nm 3 / h of air is introduced into the combustible gas reaction unit to carry out catalytic oxidation reaction at 200°C.

[0099] Among them, the steam generator pressure is 0.6MPa, the steam flow rate is 1.1t / h, and the combustible gas composition is shown in Table 2.

[0100] During the operation of the system, the reaction unit 1 did not overheat and did not explode. When the relevant parameters of the reaction unit met d1 of 0.5m, d3 of 0.1mm, δ of 0.3mm, R of 0.5m, and d2 of 0.048m, the carbon monoxide content in the treated tail gas flowing out from the tail gas discharge line 101 at the top of the reaction unit 1 was approximately 96ppm (molar percentage), and the carbon monoxide removal rate was 99.4%; when the relevant parameters of the reaction unit met the other conditions in Table 1, the carbon monoxide content in the treated tail gas flowing out from the tail gas discharge line 101 at the top of the reaction unit 1 was less than 100ppm.

[0101] Table 1 Reaction device related parameters

[0102]

[0103] Table 2

[0104] Combustible gas components Content (mol%) <![CDATA[H2]]> 2.3 <![CDATA[N2]]> 34 CO 1.8 <![CDATA[CO2]]> 61.5 <![CDATA[CH4]]> 0.3 <![CDATA[CH3OH]]> 0.1

[0105] Example Group 2

[0106] In this experimental group, the height d1 of the catalyst bed 14, the height d2 of the explosion suppression quenching packing layer 11, the spacing d3 between two adjacent corrugated plates 111, the thickness M of each corrugated plate 111, and the inner diameter R of the reaction device 1 are set as shown in Table 1. The height d1 of the catalyst bed 14, the height d2 of the explosion suppression quenching packing layer 11, the spacing d3 between two adjacent corrugated plates 111, the thickness δ of each corrugated plate 111, and the inner diameter R of the reaction device 1 satisfy the following relationship:

[0107]

[0108] Combustible gas tail gas treatment methods include:

[0109] The flow rate is 20000Nm 3 / h of combustible gas exhaust is sequentially introduced into the exhaust gas preheater 2 and the start-up heater 3 for heating, and then the heated combustible gas exhaust is mixed with a flow rate of 900Nm 3 / h of air is introduced into the combustible gas reaction unit to carry out catalytic oxidation reaction at 200°C.

[0110] Among them, the steam generator pressure is 0.6MPa, the steam flow rate is 2.3t / h, and the combustible gas composition is shown in Table 3.

[0111] During the operation of the system, the reaction unit 1 did not overheat and did not explode. When the relevant parameters of the reaction unit met d1 of 0.5m, d3 of 0.1mm, δ of 0.3mm, R of 0.5m, and d2 of 0.048m, the carbon monoxide content in the treated tail gas flowing out of the tail gas discharge line 101 at the top of the reaction unit 1 was approximately 98ppm (molar percentage), and the carbon monoxide removal rate was 99.39%; when the relevant parameters of the reaction unit met the other conditions in Table 1, the carbon monoxide content in the treated tail gas flowing out of the tail gas discharge line 101 at the top of the reaction unit 1 was less than 100ppm.

[0112] Table 3

[0113] Combustible gas components Content (mol%) <![CDATA[H2]]> 2.2 <![CDATA[N2]]> 34 CO 1.9 <![CDATA[CO2]]> 61.3 <![CDATA[CH4]]> 0.5 <![CDATA[CH3OH]]> 0.1

[0114] Example Group 3

[0115] In this experimental group, the height d1 of the catalyst bed 14, the height d2 of the explosion suppression quenching packing layer 11, the spacing d3 between two adjacent corrugated plates 111, the thickness M of each corrugated plate 111, and the inner diameter R of the reaction device 1 are set as shown in Table 1. The height d1 of the catalyst bed 14, the height d2 of the explosion suppression quenching packing layer 11, the spacing d3 between two adjacent corrugated plates 111, the thickness δ of each corrugated plate 111, and the inner diameter R of the reaction device 1 satisfy the following relationship:

[0116]

[0117] Combustible gas tail gas treatment methods include:

[0118] The flow rate is 30000Nm 3 / h of combustible gas exhaust is sequentially introduced into the exhaust gas preheater 2 and the start-up heater 3 for heating, and then the heated combustible gas exhaust is mixed with a flow rate of 1500Nm 3 / h of air is introduced into the combustible gas reaction unit to carry out catalytic oxidation reaction at 200°C.

[0119] Among them, the steam generator pressure is 0.6MPa, the steam flow rate is 3.6t / h, and the combustible gas composition is shown in Table 4.

[0120] During the operation of the system, the reaction unit 1 did not overheat and did not explode. When the relevant parameters of the reaction unit met the conditions of d1 being 0.5 m, d3 being 0.1 mm, δ being 0.3 mm, R being 0.5 m, and d2 being 0.048 m, the carbon monoxide content in the treated tail gas flowing out from the tail gas discharge line 101 at the top of the reaction unit 1 was 99 ppm (molar percentage), and the carbon monoxide removal rate was 99.38%. When the relevant parameters of the reaction unit met the other conditions in Table 1, the carbon monoxide content in the treated tail gas flowing out from the tail gas discharge line 101 at the top of the reaction unit 1 was less than 100 ppm.

[0121] Table 4

[0122] Combustible gas components Content (mol%) <![CDATA[H2]]> 2.3 <![CDATA[N2]]> 34 CO 1.6 <![CDATA[CO2]]> 61.6 <![CDATA[CH4]]> 0.3 <![CDATA[CH3OH]]> 0.2

[0123] It can be seen from the above embodiments that when the system of the present invention is used to treat carbon monoxide in combustible gas, the reaction device 1 does not overheat, does not explode, and the carbon monoxide removal rate is greater than 99%.

[0124] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A combustible gas exhaust treatment system, characterized in that: The system comprises an exhaust gas preheater (2), a start-up heater (3) and a combustible gas reaction unit which are sequentially connected along the flow direction of the combustible gas exhaust, wherein the combustible gas reaction unit comprises a reaction device (1), an explosion suppression quenching packing layer (11) is provided at one end near the bottom of the reaction device (1), a gas distributor (12) and an explosion-proof and explosion-suppressing packing layer (13) are sequentially provided on the upper part of the explosion-proof and explosion-suppressing packing layer (11) from bottom to top, a plurality of catalyst beds (14) and explosion suppression quenching packing layers (11) are alternately provided on the upper part of the explosion-proof and explosion-suppressing packing layer (13) from bottom to top, the explosion suppression quenching packing layer (11) comprises a plurality of corrugated plates (111) stacked in a direction parallel to the axial direction of the reaction device (1), and a plurality of through holes are provided on the plate body of each of the corrugated plates (111) for quenching the flame generated by the reaction raw materials; The height of the catalyst bed (14) d 1. The height of the explosion suppression and quenching packing layer (11) d 2. The distance between two adjacent corrugated plates (111) d 3. Thickness of each corrugated plate (111) δ and the inner diameter of the reaction device (1) R The following relationship is satisfied: Where M is the relative molecular mass of the combustible gas.

2. The combustible gas exhaust treatment system according to claim 1, characterized in that: Each catalyst bed (14) includes a plurality of reactors (141).

3. The combustible gas exhaust treatment system according to claim 2, characterized in that: Each reactor (141) is provided with a cooling jacket (142) for containing cooling water.

4. The combustible gas tail gas treatment system according to claim 1, characterized in that: The height of each catalyst bed (14) d 1 is 0.2~3m.

5. The combustible gas tail gas treatment system according to claim 4, characterized in that: The height of each catalyst bed (14) d 1 is 0.3~2.5m.

6. The combustible gas tail gas treatment system according to claim 1, characterized in that: The height of the explosion suppression and quenching packing layer (11) d 2 is 0.02~1.5m.

7. The combustible gas tail gas treatment system according to claim 6, characterized in that: The height of the explosion suppression and quenching packing layer (11) d 2 is 0.03~1m.

8. The combustible gas tail gas treatment system according to claim 1, characterized in that: The distance between two adjacent corrugated plates (111) d 3 is 0.05~0.5mm.

9. The combustible gas tail gas treatment system according to claim 8, characterized in that: The distance between two adjacent corrugated plates (111) d 3 is 0.1~0.3mm.

10. The combustible gas tail gas treatment system according to claim 1, characterized in that: The thickness of each corrugated plate (111) δ 0.1~2mm.

11. The combustible gas tail gas treatment system according to claim 10, characterized in that: The thickness of each corrugated plate (111) δ 0.3~1.8mm.

12. The combustible gas tail gas treatment system according to claim 1, characterized in that: The explosion-proof and explosion-suppressing filler in the explosion-proof and explosion-suppressing filler layer (13) is a porous spherical non-metallic organic material.

13. The combustible gas tail gas treatment system according to claim 1, characterized in that: The inner diameter of the reaction device (1) R 0.2~3.5m.

14. The combustible gas tail gas treatment system according to claim 13, characterized in that: The inner diameter of the reaction device (1) R 0.4~3m.

15. The combustible gas tail gas treatment system according to claim 1, characterized in that: The gas distributor (12) comprises a coil (121) and gas nozzles (122) arranged at equal intervals on the coil (121).

16. The combustible gas tail gas treatment system according to claim 4, characterized in that: The combustible gas reaction unit further comprises a cooling water supply unit and a cooling water feed pipeline (15), and cooling water from the cooling water supply unit enters the cooling jacket (142) outside each reactor (141) of the catalyst bed (14) through the cooling water feed pipeline (15).

17. The combustible gas tail gas treatment system according to claim 16, characterized in that: A cooling water feed regulating valve (16) is provided between the cooling water supply unit and the cooling water feed pipeline (15), and a cooling water flow meter (17) is provided between the cooling water feed regulating valve (16) and the catalyst bed (14).

18. The combustible gas tail gas treatment system according to claim 16 or 17, characterized in that: The combustible gas reaction unit further comprises a steam generator (18) and a cooling water discharge pipeline (19). The cooling water from the cooling water supply unit enters the steam generator (18) through the cooling water discharge pipeline (19) after heat exchange in the cooling jacket (142).

19. The combustible gas tail gas treatment system according to claim 18, characterized in that: The combustible gas reaction unit further comprises a liquid level meter (181) for monitoring the liquid level of water in the steam generator (18).

20. The combustible gas tail gas treatment system according to claim 18, characterized in that: The combustible gas reaction unit further includes a pressure gauge (182) and a thermometer (183), which are used to monitor the pressure and temperature of the steam generator (18), respectively.

21. The combustible gas tail gas treatment system according to claim 1, characterized in that: The system further comprises a flame arrester (4), which is arranged before the tail gas preheater (2) along the flow direction of the combustible tail gas.

22. The combustible gas tail gas treatment system according to claim 21, characterized in that: The system further comprises an online combustible gas monitor (5), wherein the online combustible gas monitor (5) is arranged between the flame arrester (4) and the tail gas preheater (2).

23. The combustible gas tail gas treatment system according to claim 1 or 2, characterized in that: The bottom of the reaction device (1) is provided with a combustible gas inlet (6), and the combustible gas tail gas from the start-up heater (3) enters the reaction device (1) through the combustible gas inlet (6).

24. The combustible gas tail gas treatment system according to claim 1 or 2, characterized in that: The top of the reaction device (1) is provided with a combustible gas tail gas outlet (7), and the combustible gas tail gas outlet (7) is connected to the tail gas preheater (2).

25. The combustible gas tail gas treatment system according to claim 1, characterized in that: An end of the reaction device (1) close to the bottom is provided with an air inlet (8) for introducing air into the reaction device (1).

26. A method for treating combustible gas, characterized in that: The method is implemented in the system according to any one of claims 1 to 25, and the method comprises the following steps: The combustible gas tail gas is sequentially introduced into the tail gas preheater (2) and the start-up heater (3) for heating, and then the heated combustible gas tail gas and air are introduced into the combustible gas reaction unit for catalytic oxidation reaction.

27. The method according to claim 26, characterized in that The volume flow ratio of combustible gas to air is 10~30.

28. The method according to claim 26, characterized in that The volume flow ratio of combustible gas to air is 12~25.

29. The method according to claim 26 or 27, characterized in that The conditions for the catalytic oxidation reaction include: a temperature of 150-250°C.

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