Combustible gas tail gas treatment system and method

Abstract

The invention relates to the technical field of waste gas treatment, and discloses a combustible gas tail gas treatment system and method. The system comprises a tail gas preheater, a start-up heater and a combustible gas reaction unit which are sequentially communicated in the flowing direction of combustible gas tail gas, the combustible gas reaction unit comprises a reaction device, and an explosion suppression quenching filler layer is arranged at the end, close to the bottom, of the interior of the reaction device. A gas distributor and an explosion-proof explosion-suppression filler layer are sequentially arranged at the upper part of the explosion-suppression quenching filler layer from bottom to top, and a plurality of catalyst bed layers and explosion-suppression quenching filler layers are sequentially and alternately arranged at the upper part of the explosion-proof explosion-suppression filler layer from bottom to top. According to the system provided by the invention, combustible gas and oxygen can be subjected to a gas-solid phase catalytic reaction within the explosion limit, the selectivity and conversion rate of an oxidation process are improved, and the removal rate of the combustible gas is improved.

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 tail gas. Background Art

[0002] Carbon monoxide (CO) is a colorless, odorless, toxic gas that generally comes from incomplete combustion or partial oxidation of coal, gasoline and natural gas. CO has a strong binding force with hemoglobin and is therefore highly toxic. At higher concentrations, it can cause varying degrees of poisoning symptoms in people, harming the brain, heart, liver, kidney, lungs and other tissues of the human body, and even electric shock-like death. The minimum lethal concentration for human inhalation is 5000ppm (5 minutes). Therefore, in the production process of petrochemical products, strict requirements should be made for the emission content of CO in tail gas. With increasingly stringent environmental protection requirements, Beijing, Zibo and other regions have strictly restricted the CO concentration in the tail gas of chemical plants.

[0003] At present, there are two main types of treatment technologies for treating tail gas containing CO: one is recovery technology and the other is destruction technology. Recovery technology is a method of enriching and separating CO by physical methods, such as changing temperature, pressure or adopting selective adsorbents and selective permeable membranes. It mainly includes adsorption technology, absorption technology, deep cold separation technology, membrane separation and other technologies. Destruction technology mainly uses heat, light, catalysts and microorganisms to convert organic compounds into non-toxic or low-toxic inorganic small molecule compounds such as carbon dioxide through chemical or biochemical reactions. It mainly includes direct combustion method, catalytic combustion method, biological oxidation, photocatalytic oxidation, plasma conversion method, etc. Recovery technology is mainly used to recover gases with high concentration or high economic value, while destruction technology is mainly used for treatment technologies that cannot meet environmental protection requirements or have high recovery costs.

[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 the disadvantages of high cost and complicated process. 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 content of CO and organic matter 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 the fluctuation of 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 combustion and explosion of gas-solid phase combustible systems has become a difficult problem that urgently needs to be solved in the development of quality and efficiency improvement in the chemical industry in my country and even the world.

[0005] Patent application CN110013764A discloses an ionic liquid phase change heat storage catalytic oxidation device, including a gas mixer, a flame arrester, a catalytic oxidation reactor, a phase change heat storage device, and an exhaust gas treatment device. Its technical features: It provides a new ionic liquid phase change heat storage catalytic oxidation device, which has the advantages of constant temperature during the heat storage and heat release process, high heat storage density, and good safety. This patent adopts a new heat storage body, which solves the problems of large temperature changes and low heat storage density during the heat storage and heat release process in the prior art, but does not solve the problems of overheating of the reactor and gas phase explosion in the reactor caused by high concentration of combustibles.

[0006] Patent application CN1903415A discloses a catalytic oxidation treatment process for tail gas from an acrylonitrile plant absorber, and the main technical problem to be solved is to provide a catalytic oxidation treatment process for tail gas from an acrylonitrile plant absorber with simple process, low system resistance, no need for a booster fan, no need for auxiliary fuel, low operating cost, no secondary pollution, and thorough tail gas treatment. This patent does not solve the problem of overheating of the reactor and gas phase explosion in the reactor caused by high concentration of combustibles.

[0007] Patent application CN105066148A discloses a method for treating VOCs gas by low-temperature thermal storage catalytic oxidation, providing a new method for treating VOCs gas by low-temperature thermal storage catalytic oxidation. This method is used to treat VOCs gas, and has the advantages of low safety hazards, low ignition temperature, and low energy consumption. This patent mainly reduces the ignition temperature of the reactor and solves the energy consumption problem, but does not solve the problem of overheating of the reactor and gas phase explosion in the reactor caused by high concentration of combustibles. Summary of the invention

[0008] The purpose of the present invention is to provide a system and method for treating combustible gas exhaust in order to overcome the problem that the existing combustible gas treatment device cannot well solve the problem of overheating of the reactor and gas phase explosion in the reactor caused by high concentration of combustibles. The system provided by the present invention enables the combustible gas and oxygen to undergo gas-solid phase catalytic reaction within the explosion limit, improves the selectivity and conversion rate of the oxidation process, and increases the removal rate of the combustible gas.

[0009] In order to achieve the above-mentioned objectives, the present invention provides a combustible gas exhaust treatment system on the one hand, the system comprising a tail gas preheater, a start-up heater 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, an explosion-suppressing and quenching packing layer is arranged at one end near the bottom of the reaction device, a gas distributor and an explosion-proof and explosion-suppressing packing layer are sequentially arranged on the upper part of the explosion-proof and explosion-suppressing packing layer from bottom to top, and a plurality of catalyst beds and explosion-suppressing and quenching packing layers are alternately arranged on the upper part of the explosion-proof and explosion-suppressing packing layer 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 spacing 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] Wherein, 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 outside 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 explosion suppression and quenching filler layer has a height d2 of 0.02 to 1.5 m, preferably 0.03 to 1 m.

[0018] Preferably, the distance 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 into 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 comprises 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 comprises 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 tail gas preheater along the flow direction of the combustible tail gas;

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

[0030] Preferably, the bottom of the reaction device has 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 has a combustible gas outlet, and the combustible gas outlet is connected to the exhaust 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 tail 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 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] An isothermal explosion-proof and explosion-suppressed reaction device is configured in the combustible gas reaction unit in the combustible gas tail gas treatment system described in the present invention. 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 the preferred conditions, on the one hand, the reaction device of the present invention adopts a special feeding method to mix 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, so as to ensure that carbon monoxide can be catalytically oxidized within the explosion limit. On the second hand, a steam generator is provided in the combustible gas reaction unit of the present invention, which can not only prevent the reaction device from overheating and damaging the catalyst, but also effectively recover the heat generated by the device and reduce 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, 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 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 a combustible gas reaction unit according to the present invention;

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

[0042] Figure 4 1 is a top view of the gas distributor of 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 meter; 182 pressure gauge; 183 thermometer; 184 steam pipeline; 185 pressure regulating valve. DETAILED DESCRIPTION

[0045] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0046] The endpoints and any values ​​of the ranges disclosed in this article 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 endpoint values ​​of each range, the endpoint values ​​of each range and the 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 as specifically disclosed in this article.

[0047] The first aspect of the present invention provides a combustible gas exhaust treatment system, such as Figure 1 As shown, the system includes a tail 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 tail gas. In the present invention, the combustible gas tail gas is first preheated by the tail gas preheater 2, and then the combustible gas tail gas is heated to the reaction temperature of the catalyst loaded in the reaction device 1 of the combustible gas reaction unit by the start-up heater 3, and then the heated combustible gas tail gas is passed into the reaction device 1 of the combustible gas reaction unit for catalytic oxidation reaction.

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

[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 arranged at intervals 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 also play the role of flame quenching, 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 existing green process routes, and providing an inherently safe solution for gas-solid phase catalytic reaction processes with higher explosion risks.

[0051] In a specific embodiment, Figure 3 As shown, 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 for quenching the flame generated by the reaction raw materials. Furthermore, the explosion suppression quenching packing layer 11 also includes a packing ring for fixing the plurality of stacked corrugated plates 111 to form an explosion suppression quenching packing layer 11 with a certain height.

[0052] Furthermore, the through holes provided on the corrugated plate 111 can change the direction of the airflow, so that the flame cannot propagate and quench the flame. The through holes can be holes of various shapes, such as circular holes, triangular holes, square holes or rectangular holes, preferably rectangular holes. The multiple through holes can be holes of the same shape or holes of different shapes.

[0053] According to the present invention, the material of the corrugated plate 111 needs to be specifically selected according to the reaction raw materials of the reaction device 1. For example, when the reaction raw materials contain acidic gas, it is necessary to select a material resistant to acid corrosion, such as aluminosilicate acid-resistant and chemical-resistant ceramic material. Further, the reaction device 1 can be a reactor in which the gas phase performs a gas-solid phase catalytic reaction under the catalytic action of a solid phase catalyst.

[0054] In the present invention, by alternately installing multiple catalyst beds 14 and multiple explosion-suppressing 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 be operated 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 proposes the structure-activity relationship between the distance d3 between two adjacent corrugated plates 111 in the explosion suppression quenching packing layer 11, the height d2 of the explosion suppression 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 quenching packing layer 11 and the height d1 of the catalyst bed 14, so as to design the matching form between different types of explosion suppression 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 having the 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] Wherein, 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, and pass 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, and 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 arranged at one end of the reaction device 1 close to the bottom, one end of the reaction device 1 close to the top, and between 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 catalyst beds 14 and explosion suppression and quenching filler layers 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-suppressing 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-suppressing 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-suppressing 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-suppressing and quenching packing layer 11, a catalyst bed 14, an explosion-suppressing and quenching packing layer 11, a catalyst bed 14, and an explosion-suppressing 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-suppressing and quenching packing layer 11 is arranged between two catalyst beds 14, and finally an explosion-suppressing and quenching packing layer 11 is arranged at one end of the reaction device 1 close to 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 in a conventional manner 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, and 3 reactors 141 are 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. By passing cooling water into the cooling jacket 142, cooling by passing cooling water can prevent the catalyst bed 14 from overheating due to high concentration of combustible gas and damage to the catalyst and the reactor. At the same time, the circulation of cooling water ensures that the combustible gas is catalytically reacted at a constant temperature in the catalyst bed 14.

[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, and 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 may correspond to a cooling water feed pipeline 15. Specifically, a main pipeline may be set from the output end of the cooling water supply unit, and then divided from the main pipeline into a plurality of cooling water feed pipelines 15, and the plurality of cooling water feed pipelines 15 are respectively connected to the plurality of catalyst beds 14 to transport the cooling water to the cooling jacket 142 in each catalyst bed 14. The source of the cooling water is not limited, and it may be pure water or boiler water generated in other process, 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, and the cooling water feed regulating valve 16 is used to regulate the amount of cooling water entering the catalyst bed 14, so as to ensure that the catalytic deoxygenation reaction in the catalyst bed 14 can be carried out at a constant temperature. More preferably, a cooling water feed regulating valve 16 can be provided on each cooling water feed pipeline 15 to separately 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 introduced 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 filler layer 11, the distance 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 above-mentioned 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 choice commonly used in the art. The explosion-proof and explosion-suppressing filler layer 13 can not only play a role in flame retardancy and explosion prevention, but also can promote the reaction raw materials entering the first catalyst bed 14 to be more evenly distributed 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 arranged on the coil 121. In order to make the combustible gas and oxygen enter the explosion-proof and explosion-suppressing filler layer 13 and the catalyst bed layer 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 enters the steam generator 18 through the cooling water discharge pipeline 19 after heat exchange in the cooling jacket 142. 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 the 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 taken away from the catalyst bed 14 through the cooling water discharge pipeline 19, and the heat in the catalyst bed 14 can be taken away, so that the catalyst bed 14 is operated at a constant temperature, thereby preventing the catalyst and the reactor from being damaged due to overheating of the catalyst bed caused by excessive concentration of combustible gas, and at the same time avoiding abnormal operating conditions such as excessive temperature causing the catalyst bed to catch fire.

[0080] In the present invention, preferably, the combustible gas reaction unit also 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, preferably, the combustible gas reaction unit 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 the DCS control device to form an interlocking control. The DCS control device is configured to control the opening of the pressure regulating valve 185 according to the pressure signal of the steam generator 18 monitored by the pressure gauge 182. When in use, the pressure in the steam generator 18 is monitored in real time by the pressure gauge 182, and the opening of the pressure regulating valve 185 is controlled by feedback adjustment, so that the steam generated in the steam generator 18 is discharged in time to ensure the safe operation of the steam generator 18. The thermometer 183 is used to detect the real-time temperature in the steam generator 18.

[0082] In a specific embodiment, the top of the steam generator 18 has a steam outlet, and the steam outlet is connected to a steam pipeline 184, which is used to extract and reuse the steam generated by the steam generator 18. 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 comprises 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 spreads in the reverse direction opposite to 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 arranged 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 combustible tail gas online.

[0085] In the combustible gas exhaust treatment system of the present invention, preferably, the bottom of the reaction device 1 has 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 has 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, and 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 tail gas, which is implemented in the system described above and comprises the following steps:

[0088] 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.

[0089] In the method of the present invention, specifically, during the catalytic oxidation reaction of the combustible gas exhaust and air into 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 heat exchange with the cooling water enters the steam generator 18, effectively recovering the heat of the reaction device 1.

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

[0091] In the method of the present invention, the conditions of the catalytic oxidation reaction include: a temperature of 150-250° C. In the present invention, the catalyst used in the catalytic oxidation reaction can be a conventional choice 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 protection scope 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 embodiments 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 sequentially connected 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 arranged at one end near the bottom of the reaction device 1, and a gas distributor 12 and an explosion-proof and explosion suppression packing layer 13 are sequentially arranged on the upper part of the explosion-proof and explosion suppression packing layer 11 from bottom to top, and a plurality of catalyst beds 14 and explosion suppression quenching packing layers 11 are alternately arranged on the upper part of the explosion-proof and explosion suppression packing layer 13 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 It is used to quench the flames 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) outside for containing cooling water. The catalyst carrier loaded in the reactor 141 is a honeycomb Al2O3, and 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, which are respectively used to monitor the liquid level of water in the steam generator 18. 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 exhaust, 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, and 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 exhaust outlet 7, and the combustible gas exhaust outlet 7 is connected to the exhaust gas preheater 2. The end of the reaction device 1 close to 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] The methods for treating combustible tail gas include:

[0098] The flow rate is 12000Nm 3 / h 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 is mixed with the 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 device 1 did not overheat and did not explode. When the relevant parameters of the reaction device satisfied 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 device 1 was about 96ppm (molar percentage), and the carbon monoxide removal rate was 99.4%; when the relevant parameters of the reaction device 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 device 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] The methods for treating combustible tail gas include:

[0109] The flow rate is 20000Nm 3 / h 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 is mixed with the 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 device 1 did not overheat and did not explode. When the relevant parameters of the reaction device satisfied 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 device 1 was about 98ppm (molar percentage), and the carbon monoxide removal rate was 99.39%; when the relevant parameters of the reaction device 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 device 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] The methods for treating combustible tail gas include:

[0118] The flow rate is 30000Nm 3 / h 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 is mixed with the 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 device 1 did not overheat and did not explode. When the relevant parameters of the reaction device satisfied 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 device 1 was 99ppm (molar percentage), and the carbon monoxide removal rate was 99.38%; when the relevant parameters of the reaction device 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 device 1 was less than 100ppm.

[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 are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A combustible gas tail gas 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 arranged 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 arranged on the upper part of the explosion-proof and explosion-suppressing packing layer (13) from bottom to top, and a plurality of catalyst beds (14) and explosion suppression quenching packing layers (11) are alternately arranged on the upper part of the explosion-proof and explosion-suppressing packing layer (13) from bottom to top.

2. The combustible gas tail gas treatment system according to claim 1, characterized in that: The explosion suppression and quenching filler 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.

3. The combustible gas tail gas treatment system according to claim 2, characterized in that: The height d1 of the catalyst bed (14), the height d2 of the explosion suppression and quenching filler layer (11), the distance 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: Wherein, M is the relative molecular mass of the combustible gas.

4. The combustible gas tail gas treatment system according to any one of claims 1 to 3, characterized in that: Each catalyst bed (14) includes a plurality of reactors (141); Preferably, each reactor (141) is provided with a cooling jacket (142) outside for containing cooling water.

5. The combustible gas tail gas treatment system according to any one of claims 1 to 4, characterized in that: The height d1 of each catalyst bed (14) is 0.2 to 3 m, preferably 0.3 to 2.5 m.

6. The combustible gas tail gas treatment system according to any one of claims 1 to 5, characterized in that: The height d2 of the explosion suppression and quenching filler layer (11) is 0.02 to 1.5 m, preferably 0.03 to 1 m.

7. The combustible gas tail gas treatment system according to any one of claims 1 to 6, characterized in that: The distance d3 between two adjacent corrugated plates (111) is 0.05 to 0.5 mm, preferably 0.1 to 0.3 mm; Preferably, the thickness δ of each corrugated plate (111) is 0.1 to 2 mm, preferably 0.3 to 1.8 mm.

8. The combustible gas tail gas treatment system according to any one of claims 1 to 7, 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.

9. The combustible gas tail gas treatment system according to any one of claims 1 to 8, characterized in that: The inner diameter R of the reaction device (1) is 0.2 to 3.5 m, preferably 0.4 to 3 m.

10. The combustible gas tail gas treatment system according to any one of claims 1 to 9, characterized in that: The gas distributor (12) comprises a coil (121) and gas nozzles (122) arranged at equal intervals on the coil (121).

11. The combustible gas tail gas treatment system according to any one of claims 5 to 10, 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 into a cooling jacket (142) outside each reactor (141) of the catalyst bed (14) through the cooling water feed pipeline (15).

12. The combustible gas tail gas treatment system according to claim 11, 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).

13. The combustible gas tail gas treatment system according to claim 11 or 12, characterized in that: The combustible gas reaction unit further comprises a steam generator (18) and a cooling water discharge pipeline (19), wherein 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).

14. The combustible gas tail gas treatment system according to claim 13, 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); Preferably, the combustible gas reaction unit further comprises a pressure gauge (182) and a thermometer (183), which are used to monitor the pressure and temperature of the steam generator (18), respectively.

15. 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; Preferably, the system further comprises an online combustible gas monitor (5), and the online combustible gas monitor (5) is arranged between the flame arrester (4) and the exhaust gas preheater (2).

16. 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); Preferably, the top of the reaction device (1) is provided with a combustible gas outlet (7), and the combustible gas outlet (7) is connected to the exhaust gas preheater (2).

17. The combustible gas tail gas treatment system according to any one of claims 1 to 16, characterized in that: The reaction device (1) has an air inlet (8) at one end close to the bottom, which is used to introduce air into the reaction device (1).

18. A method for treating combustible gas, characterized in that: The method is implemented in the system according to any one of claims 1 to 17, 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.

19. The method according to claim 18, characterized in that The volume flow ratio of combustible gas exhaust to air is 10-30, preferably 12-25.

20. The method according to claim 18 or 19, characterized in that The conditions for the catalytic oxidation reaction include: a temperature of 150-250°C.

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