A pipeline reactor, process waste gas treatment system and method

Abstract

The present invention discloses a pipeline reactor, a process waste gas treatment system and a method, which belongs to the field of pan-semiconductor waste gas treatment technology and is used to solve the problem that the prior art cannot effectively remove NO X , the water content in the exhaust gas is too high and combined with dust to stick to the inner wall of the pipeline, causing pipeline blockage. In the pipeline reactor, the physical deliquescence bed is used to reduce the humidity of the exhaust gas, NO X , part of the water vapor flows into the chemical catalytic reaction bed; ozone is introduced into the chemical catalytic reaction bed; the chemical catalytic reaction bed includes active components, in the chemical catalytic reaction bed, under the action of the active components, the water vapor is catalytically decomposed into hydroxyl free radicals, the ozone is catalytically decomposed into oxygen free radicals, and the hydroxyl free radicals and the oxygen free radicals oxidize NOx into NO2 and / or N2O5. The present invention can be used for process waste gas treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of pan-semiconductor waste gas treatment, and in particular relates to a pipeline reactor, a process waste gas treatment system and a method. Background Art

[0002] In the process of pan-semiconductor manufacturing, the reaction chamber temperature of the process waste gas treatment system (Local Scrubber) that uses combustion water washing, plasma water washing or other methods to treat waste gas is relatively high (>1000°C). The waste gas comes into contact with a large amount of air or nitrogen at high temperature, which will produce a large amount of nitrogen oxides (NO X ), which mainly include NO and NO2. These nitrogen oxides cannot be effectively removed by the alkali washing tower at the plant end connected to the back end of the process waste gas treatment system, resulting in NO X Escape occurs, causing harm to the environment.

[0003] In addition, the waste gas from processes such as Chemical Vapor Deposition (CVD) and etching (ETCH) contains a large amount of dust, which is usually removed by spraying water. However, this will greatly increase the water content in the waste gas. When the waste gas subsequently flows through the factory pipes, the water vapor in the waste gas will cool and liquefy and combine with the dust that has not been removed in the waste gas to stick to the inner wall of the pipe, causing the pipe to be blocked. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a pipeline reactor, a process waste gas treatment system and a method to solve the problem that the prior art cannot effectively remove NO X 2. The water content in the exhaust gas is too high and combines with the dust to stick to the inner wall of the pipe, causing at least one problem of pipe blockage.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions.

[0006] The present invention provides a pipeline reactor for water and NO in process waste gas X The process includes a shell and a physical deliquescence bed and a chemical catalytic reaction bed sequentially arranged in the shell along the flow direction of the exhaust gas; the exhaust gas inlet of the shell is connected to the exhaust gas outlet of the spray tower of the process exhaust gas treatment system, and the exhaust gas discharged from the exhaust gas outlet of the spray tower contains water vapor and NO X ; Physical deliquification bed is used to remove part of the water vapor in the exhaust gas, NO Xand the remaining water vapor flows into the chemical catalytic reaction bed; the chemical catalytic reaction bed includes active components; the chemical catalytic reaction bed is used for catalytic oxidation reaction of ozone, NOx and water vapor; in the chemical catalytic reaction bed, ozone, NOx and water vapor are mixed, diffused and mass transferred in the gap of the bed layer of the chemical catalytic reaction bed, and under the action of the active components, the water vapor is catalytically decomposed into hydroxyl free radicals, the ozone is catalytically decomposed into oxygen free radicals, the hydroxyl free radicals and the oxygen free radicals undergo oxidation reaction with NOx, and NOx is oxidized into NO2 and / or N2O5.

[0007] Furthermore, an ozone inlet hole is provided on the shell, and the ozone outlet of the ozone generator is connected with the ozone inlet hole on the shell, and the ozone inlet hole is located at the lower side of the chemical catalytic reaction bed.

[0008] Furthermore, the pipeline reactor also includes a supporting grid and a pressing grid. The supporting grid is located on a side of the physical deliquidation bed away from the chemical catalytic reaction bed, and the pressing grid is located on a side of the chemical catalytic reaction bed away from the physical deliquidation bed.

[0009] Furthermore, the outer shell includes a cylinder and a lining material arranged on the inner wall of the cylinder.

[0010] Furthermore, the pipeline reactor also includes a supporting grid, which is located on a side of the physical dehydration bed away from the chemical catalytic reaction bed; the lining material includes a first lining material and a second lining material, the second lining material is located between the cylinder and the physical dehydration bed, and the first lining material is arranged on the inner wall of the cylinder and is located below the second lining material; the supporting grid is located between the first lining material and the second lining material, the outer edge of the upper surface of the supporting grid is in contact with the lower edge of the second lining material, and the outer edge of the lower surface of the supporting grid is in contact with the upper edge of the first lining material, and the thickness of the first lining material is greater than the thickness of the second lining material.

[0011] The present invention also provides a process waste gas treatment system, comprising a reaction chamber, a water tank, a spray tower and a pipeline reactor which are sequentially connected along the waste gas flow direction, and the pipeline reactor is the above-mentioned pipeline reactor.

[0012] Furthermore, the water tank includes a baffle and a cyclone assembly, the inner cavity of the water tank is divided into a spray water cavity and an exhaust gas cavity in the vertical direction, the baffle is arranged in the exhaust gas cavity, the baffle divides the exhaust gas cavity into a mixed flow cavity and an exhaust cavity which are connected in sequence along the moving direction of the exhaust gas; the cyclone assembly is arranged in the exhaust cavity, the cyclone assembly includes at least one first side arc plate and a W-shaped plate, the first side arc plate protrudes toward the baffle, the W-shaped plate is located on the side of the first side arc plate away from the baffle, the W-shaped plate includes two second side arc plates arranged in parallel and protruding away from the baffle, the bottom end of the first side arc plate and the bottom end of the second side arc plate have a gap as two openings; the exhaust gas flowing into the exhaust cavity from the mixed flow cavity contacts the side of the first side arc plate, and is divided into two tangential airflows by the side of the first side arc plate, and enters the airflow channel formed by the first side arc plate and the W-shaped plate through the two openings respectively, and forms two symmetrical cyclones under the guidance of the two second side arc plates.

[0013] The present invention also provides a method for treating process waste gas, comprising the following steps:

[0014] Step 1: The waste gas after thermal decomposition in the reaction chamber and water washing in the spray tower contains nitrogen oxides and water vapor. Part of the water vapor in the waste gas after thermal decomposition in the reaction chamber and water washing in the spray tower is removed in a physical deliquidation bed;

[0015] Step 2: The remaining water vapor and nitrogen oxides in the exhaust gas pass through the gaps of the physical deliquidation bed and enter the chemical catalytic reaction bed;

[0016] Step 3: Ozone is introduced into the chemical catalytic reaction bed. Under the action of the active components, water vapor is catalytically decomposed into hydroxyl free radicals, and ozone is catalytically decomposed into oxygen free radicals.

[0017] Hydroxyl free radicals and oxygen free radicals react with NOx on the surface of active components to convert NOx into NO2 and / or N2O5 that are easily soluble in water, thereby obtaining exhaust gas after dehumidification and removal of NOx.

[0018] Step 4: The exhaust gas after dehumidification and removal of NOx passes through an alkaline scrubber to remove NO2 and / or N2O5.

[0019] Furthermore, the active component is one or more of manganese oxide, iron oxide, chromium oxide and nickel oxide.

[0020] Furthermore, the chemical catalytic reaction bed includes a substrate and a coating applied to the exposed outer surface of the substrate, and the active components are located in the coating; the coating comprises aluminum oxide; the exhaust gas after thermal decomposition in the reaction chamber and water washing by the spray tower contains HF acid, and the HF acid reacts with the aluminum oxide to generate AlF3 which remains in the coating.

[0021] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects.

[0022] A) The pipeline reactor and process waste gas treatment method provided by the present invention combine physical liquid removal and chemical gas-solid phase catalytic reaction, and can simultaneously treat NOx, water vapor and dust in the process waste gas. NOx can be efficiently removed using a lower amount of ozone, and the cost of waste gas treatment is low and the amount of ozone escape is effectively reduced to avoid secondary pollution. Removing water vapor and dust can also avoid blockage of the plant service pipeline connected to the rear end of the pipeline reactor.

[0023] B) The pipeline reactor and process waste gas treatment method provided by the present invention contain a large amount of NOx (the volume percentage of NO is more than 90%) and water vapor in the waste gas after thermal decomposition and spray water washing. When flowing through the physical deliquidation bed, water vapor and dust above the micron level will be captured and intercepted by the physical deliquidation bed due to inertia, and most of the water vapor and dust are efficiently removed, and the humidity and dust content of the waste gas are significantly reduced, thereby avoiding blockage of the plant service pipeline connected to the rear end of the pipeline reactor.

[0024] C) The pipeline reactor and process waste gas treatment method provided by the present invention, when reaching the chemical catalytic reaction bed through the physical bed, there is still a trace amount of water vapor combined with NO X In the chemical catalytic reaction bed, O3, NOx and trace water vapor will mix, diffuse and transfer in the interlaced gaps of the bed. Under the action of active components, water molecules are catalytically decomposed into hydroxyl radicals (·OH) and removed, and O3 is catalytically decomposed into oxygen radicals (·O). Since the oxidation potentials of ·OH and ·O are higher than those of O3, their oxidizing properties are significantly stronger than those of O3, and they can be generated and reacted with NO in real time on the surface of active components. X Oxidation reaction occurs, making NO X It is converted into NO2 and / or N2O5 which are easily soluble in water, and then removed by the alkali washing tower of the plant, thus improving the overall NOx removal rate. The setting of the chemical catalytic reaction bed uses ozone to catalyze the trace water vapor below the micron level escaping from the upstream under the action of active components to produce highly oxidizing ·OH, thus improving the removal efficiency of NO and final NOx, and achieving the effect of removing NOx with less O3.

[0025] D) The pipeline reactor and process waste gas treatment method provided by the present invention use water vapor as a reactant while removing NOx in the chemical catalytic reaction bed, thereby preventing the residual water vapor from entering the exhaust pipe at the plant end and condensing and liquefying and combining with the escaped dust, agglomerating and adhering to the inner wall of the plant pipe, thereby blocking the pipe and effectively reducing the maintenance cycle.

[0026] E) The chemical catalytic reaction bed of the pipeline reactor of the present invention uses a metal wire mesh demister or a metal corrugated structured packing as a matrix, which can act as a gas uniform mixer on the one hand, so that O3 can be fully diffused in the gap channel and fully merged with the exhaust gas flowing through, thereby extending the residence time; on the other hand, it has a large external specific surface area, which helps to highly disperse the active components to form more active sites, and is beneficial for O3, NOx, H2O to fully contact with the active components and undergo decomposition and oxidation reactions.

[0027] F) The pipeline reactor of the present invention can be connected in series to the process waste gas treatment system through flanges in a skid-type manner for use, and its performance can be directly improved and modified during use, which is easy to operate.

[0028] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the embodiments of the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present invention. In the entire drawings, the same reference symbols represent the same components;

[0030] Figure 1 A schematic diagram of the structure of the pipeline reactor provided by the present invention;

[0031] Figure 2 A schematic diagram of the structure of a water tank in the process waste gas treatment system provided by the present invention;

[0032] Figure 3 A front view of a water tank in the process waste gas treatment system provided by the present invention;

[0033] Figure 4 This is a schematic diagram of the structure of a W-shaped plate in the process waste gas treatment system provided by the present invention.

[0034] Reference numerals:

[0035] 1-shell; 2-ozone air inlet; 3-physical deliquidation bed; 4-chemical catalytic reaction bed; 5-first flange; 6-second flange; 7-supporting grid; 8-pressing grid; 9-first lining material; 10-second lining material; 11-baffle; 12-spray water chamber; 13-mixing chamber; 14-exhaust chamber; 141-guide plate; 15-first side arc plate; 151-opening; 152-connecting plate; 16-W-shaped plate. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0037] The present invention provides a pipeline reactor for water and NO in waste gas X For removal, see Figure 1 , comprising a housing 1 (e.g., a stainless steel housing) and a physical deliquidation bed 3 and a chemical catalytic reaction bed 4 sequentially arranged in the housing 1 along the flow direction of the exhaust gas, the exhaust gas inlet of the housing 1 is connected to the exhaust gas outlet of the spray tower of the process exhaust gas treatment system; the exhaust gas discharged from the exhaust gas outlet of the spray tower contains a large amount of water vapor and NO X The physical deliquidation bed 3 can use a wire mesh demister. The waste gas after spraying and washing passes through the physical deliquidation bed 3 to remove large particles of dust and water vapor. At this time, some small particles of water vapor have not been removed. Specifically, the physical deliquidation bed 3 can remove water vapor with a particle size of more than 1 and dust with a particle size of less than 1 μm.

[0038] NO X , the remaining water vapor flows into the chemical catalytic reaction bed 4. The chemical catalytic reaction bed 4 can use a metal wire mesh demister or a metal corrugated structured filler. Ozone is introduced into the chemical catalytic reaction bed 4 coated with active components. Under the action of the active components in the chemical catalytic reaction bed 4, the water vapor will be catalytically decomposed into hydroxyl radicals (·OH), and the ozone will be catalytically decomposed into oxygen radicals (·O). Under the joint action of hydroxyl radicals, oxygen radicals and active components, NOx will be oxidized into NO2 and / or N2O5. In this embodiment, an ozone generator can be used to generate ozone. In other embodiments, an oxygen source, air source or hydrogen peroxide can also be used to provide ozone. Because NO in the exhaust gas X Mainly NO, NO is subsequently used to remove NO from the pipeline reactor of the present invention X The process and principle are explained.

[0039] The active component is one or more of manganese oxide, iron oxide, chromium oxide, and nickel oxide, and the mass ratio of the active component in the coating is 5-13%. This is because if the mass ratio of the active component to the coating is too small, the number of active sites formed will be insufficient, and the catalytic ozone oxidation effect will be poor; if it is too large, the proportion of the coating will be reduced, the amount of the coating on the substrate will be insufficient, and the protective effect of the coating on the substrate will be reduced. At the same time, the low loading will actually reduce the content of the active component, and the number of effective active sites formed will also decrease.

[0040] The active components are manganese oxide and iron oxide. Manganese oxide, iron oxide or other non-precious metal oxides mainly composed of transition metals are low-cost and low-toxic.

[0041] Compared with the prior art, the pipeline reactor provided by the present invention combines physical liquid removal and chemical gas-solid phase catalytic reaction, making the equipment multifunctional. It can not only treat process waste gas, NOx and water vapor at the same time, improve the original treatment efficiency, but also reduce the amount of ozone used, reduce the amount of ozone escape, and avoid secondary pollution.

[0042] Specifically, the exhaust gas after thermal decomposition and spray water washing contains a large amount of NOx (the volume percentage of NO is more than 90%) and water vapor, and the temperature is about 30~40℃. When flowing through the physical deliquidation bed 3, the large-sized water vapor will be captured and intercepted by the physical deliquidation bed 3 due to inertia. Most of the water vapor is removed efficiently, and the exhaust gas humidity is significantly reduced. However, there is still a trace of water vapor that will be mixed with NO X Together, they pass through the gaps in the physical deliquescence bed 3 and enter the chemical catalytic reaction bed 4 .

[0043] In the chemical catalytic reaction bed 4, O3, NOx and trace water vapor will mix, diffuse and transfer in the criss-crossing gaps of the bed. Under the action of the active components, water molecules are catalytically decomposed into hydroxyl radicals (·OH) and removed, and O3 is catalytically decomposed into oxygen radicals ·O. Since the oxidation potentials of ·OH and ·O are higher than that of O3 (2.07 eV), their oxidizing properties are significantly stronger than O3. Although the survival time of ·OH and ·O is short, they can still be generated on the surface of the active components in real time and react with NO in real time. X Oxidation reaction occurs, making NO X It is converted into NO2 and / or N2O5 which are easily soluble in water, and then removed by the plant's alkali washing tower to improve the overall NOx removal rate.

[0044] The chemical catalytic reaction bed 4 is set up, and ozone is used to catalyze the water molecules escaping from the upstream to produce strong oxidizing OH under the action of active components, thereby improving the removal efficiency of NO and final NOx, reducing the original use of O3, and removing water vapor at the same time, preventing the water vapor from condensing and liquefying after entering the exhaust pipe and combining with the escaped dust, agglomerating and adhering to the inner wall of the plant service pipeline, blocking the pipeline, and effectively reducing the difficulty of maintenance.

[0045] It should be noted that, for the above-mentioned pipeline reactor, a physical deliquidation bed 3 must be set before the chemical catalytic reaction bed 4 to remove a large amount of large-sized water vapor in the exhaust gas, and only retain a trace amount of small-molecule water vapor to enter the chemical catalytic reaction bed 4. This is because when the water vapor content is too high, it will compete with O3 for adsorption, and some active sites will be covered by water molecules, the ability to decompose ozone will be reduced, and the number of active oxygen free radicals generated will decay, resulting in NO cannot be completely oxidized and converted. The physical deliquidation bed 3 is set to ensure that the water vapor entering the chemical catalytic reaction bed 4 is kept within a reasonable range, which can be catalyzed to produce strongly oxidizing OH, and will not compete with O3 for adsorption, fully ensuring the desired reaction direction.

[0046] In order to achieve communication between the housing 1 and the ozone generator, it is understandable that an ozone inlet 2 is provided on the housing 1, and the ozone outlet of the ozone generator is connected to the ozone inlet 2 on the housing 1 to achieve ozone supply.

[0047] Exemplarily, there are multiple ozone inlet holes 2, for example, 2 to 6, and the multiple ozone inlet holes 2 are evenly arranged along the axial direction of the housing 1 to ensure uniformity of ozone supply.

[0048] In order to prolong the ozone, active components and NO X The lower edge of the ozone inlet 2 is located at the same horizontal line as the lower surface of the chemical catalytic reaction bed 4, so that the dehumidified exhaust gas can react as soon as it enters the chemical catalytic reaction bed 4. Preferably, the ozone inlet 2 can also be arranged tangentially along the shell 1, so that ozone is introduced tangentially along the shell 1, further extending the residence time of ozone in the chemical catalytic reaction bed 4, so that ozone, active components and NO X Fully respond.

[0049] It can be understood that the chemical catalytic reaction bed 4 further includes a substrate and a coating coated on the exposed outer surface of the substrate, and the active components are located in the coating.

[0050] The substrate is a metal mesh demister or a metal corrugated structured packing. With a metal mesh demister or a metal corrugated structured packing as the substrate, on the one hand, the substrate can act as a gas mixer, and the abundant gaps form complex channels, prolonging the residence time, so that the different gas components flowing through are fully mixed and the mutual reaction rate is increased. On the other hand, the substrate has a larger surface area, which increases the loading amount of the coating, forms more catalytic active sites, and makes the reacted gas components contact the active sites more fully.

[0051] As for the material of the substrate, illustratively, the material of the substrate is one of carbon steel, stainless steel, and aluminum. From the perspective of corrosion resistance, the material of the substrate is stainless steel.

[0052] For the coating, its composition includes alumina or a mixture of alumina and other metal oxides that are sticky when in contact with water. Alumina and other metal oxides that are sticky when in contact with water are selected as binders in the catalyst molding process to bond the components to the carrier material, and increase the strength of the molded catalyst without affecting the activity and selectivity of the catalyst. Alumina and other metal oxides that are sticky when in contact with water account for 2-10% by mass in the coating, filling the gaps in the molded object to improve its plasticity and increase the bonding strength between particles, and have both dilution and lubrication effects. It should be noted that the use of alumina as a coating, on the one hand, as a large specific surface area carrier of the active component, promotes the diffusion and dispersion of the active component, and forms more active sites; on the other hand, it can effectively protect the metal matrix and the inner wall of the downstream pipeline from F- erosion. Specifically, when the trace HF acid (small amount but extremely corrosive) entrained in the exhaust gas flows through the chemical catalytic reaction bed 4, it will react with the alumina of the coating to generate AlF3 and stay in the coating, achieving the effect of capturing and intercepting F- and protecting the downstream pipeline.

[0053] Exemplarily, the height of the chemical catalytic reaction bed 4 is not less than 30 mm, and is not less than the ratio of the diameter of the chemical catalytic reaction bed 4 to the number of ozone inlet holes 2. For example, the height of the chemical catalytic reaction bed 4 is 80-150 mm. The height of the chemical catalytic reaction bed 4 is set in this way for the following purposes: on the one hand, the height of the chemical catalytic reaction bed 4 is limited within the above range, which can ensure that the ozone entering the chemical catalytic reaction bed 4 is fully mixed with other gases flowing through; on the other hand, the length of the air flow channel inside the chemical catalytic reaction bed 4 can be extended to ensure the residence time of ozone, make full use of active components, and improve the removal rate of NO; ​​on the other hand, since ozone enters from the bottom side of the chemical catalytic reaction bed 4, once the height of the chemical catalytic reaction bed 4 is too low, ozone will quickly escape from the upper surface of the bed layer, fail to fully participate in the reaction, and easily cause secondary pollution.

[0054] In order to achieve effective water vapor separation, the physical degassing bed 3 includes a wire mesh demister with a height of 100-150 mm, a porosity of 87.5-91.3%, and a specific surface area of ​​900-1520 m 2 / m 3 The wire diameter is 0.6~1.0mm, and the material is one of PTFE, PFA, PVDF, etc. In this way, by selecting a wire mesh demister of appropriate specifications, the best effect of removing mist and liquid foam can be achieved.

[0055] In order to facilitate the connection of the shell 1 with other treatment units (such as a spray tower) of the process waste gas treatment system and subsequent plant services (such as an exhaust pipe), the shell 1 also includes a connecting flange (such as a stainless steel connecting flange) arranged at its end. By way of example, there are two connecting flanges, namely a first flange 5 and a second flange 6. The first flange 5 and the second flange 6 are respectively arranged at both ends of the shell 1. For example, the first flange 5 is arranged at the upper end of the shell 1, and the second flange 6 is arranged at the lower end of the shell 1. At this time, the shell 1 can be detachably fixedly connected to the spray tower through the first flange 5, and the shell 1 can be detachably fixedly connected to the exhaust pipe through the second flange 6.

[0056] In order to achieve stable installation of the physical dehydration bed 3 and the chemical catalytic reaction bed 4, the above-mentioned pipeline reactor also includes a supporting grid 7 and a pressing grid 8. The supporting grid 7 is located on the side of the physical dehydration bed 3 away from the chemical catalytic reaction bed 4, and the pressing grid 8 is located on the side of the chemical catalytic reaction bed 4 away from the physical dehydration bed 3. Taking the pipeline reactor being vertically arranged and the flow direction of the exhaust gas in the pipeline reactor being from bottom to top as an example, the supporting grid 7, the physical dehydration bed 3, the chemical catalytic reaction bed 4 and the pressing grid 8 are arranged in contact with each other in sequence from bottom to top.

[0057] The compression grid 8 is provided to ensure that the chemical catalytic reaction bed 4 can be in close contact with the physical deliquification bed 3 to avoid a gap between the two. In addition, during the flow of the exhaust gas, the displacement of the chemical catalytic reaction bed 4 caused by the impact of the airflow is avoided to ensure that the ozone can be fully diffused in the chemical catalytic reaction bed 4 and fully mixed with the nitrogen oxides and water vapor in the exhaust gas to ensure the efficiency of the reaction.

[0058] Exemplarily, the thickness of the supporting grid 7 is 4-6 mm, and the material is one of PTFE, PFA, New-PTFE, etc.

[0059] As for the structure of the shell 1, specifically, it includes a cylinder and a lining material arranged on the inner wall of the cylinder, and the material of the lining material is one of PTFE, PFA, and New-PTFE.

[0060] Exemplarily, there are two lining materials, namely the first lining material 9 and the second lining material 10. The second lining material 10 is sleeved on the outer wall of the physical dehydration bed 3 and is located between the cylinder and the physical dehydration bed 3. The height of the second lining material 10 is equal to the height of the physical dehydration bed 3. The first lining material 9 is arranged on the inner wall of the cylinder and is located below the second lining material 10. The first lining material 9 and the second lining material 10 are both attached to the inner wall of the cylinder by plate lining. The supporting grid 7 is located between the first lining material 9 and the second lining material 10. The outer edge of the upper surface of the supporting grid 7 is in contact with the lower edge of the second lining material 10, and the outer edge of the lower surface of the supporting grid 7 is in contact with the upper edge of the first lining material 9. The bonding method is hot melt bonding or ultrasonic welding. Among them, the first lining material 9 has a dual role. On the one hand, it is used to support the supporting grid 7, the physical dehydration bed 3, the chemical catalytic reaction bed 4 and the compression grid 8. On the other hand, it can reduce the corrosion of the inner wall of the cylinder. The second lining material 10 is mainly used to protect the cylinder around the physical dehydration bed 3 and reduce the corrosion of the inner wall of the cylinder.

[0061] It is worth noting that the lower surface of the first flange 5 will directly contact the exhaust gas. In order to protect the lower surface of the first flange 5, the structure of the first lining material 9 includes a liner and a liner ring connected to the lower end of the liner (i.e., the flange structure of the first lining material 9). The liner is attached to the inner wall of the cylinder, and the liner ring is attached to the lower surface of the first flange 5. The liner ring does not cover the flange threaded hole of the first flange 5. In this way, not only can the lower surface of the first flange 5 be effectively protected and corrosion reduced, but also the connection sealing performance between the first flange 5 and the spray tower can be improved.

[0062] Taking into account that the weight of the supporting grid 7, the physical dehydration bed 3, the chemical catalytic reaction bed 4 and the compression grid 8 is mainly borne by the first lining material 9, the thickness of the first lining material 9 is 1.5-3.5 mm. In this way, it can not only ensure that the first lining material 9 has sufficient mechanical strength and the installation stability of the supporting grid 7, the physical dehydration bed 3, the chemical catalytic reaction bed 4 and the compression grid 8, but also appropriately reduce the use of raw materials and reduce the production cost of the pipeline reactor.

[0063] In order to ensure the isolation between the physical deliquidation bed 3 and the cylinder, the thickness of the second lining material 10 is 1-1.5 mm, for example. That is, the thickness of the first lining material 9 is preferably greater than the thickness of the second lining material 10 .

[0064] The present invention also provides a process waste gas treatment system, which includes a reaction chamber, a water tank, a spray tower and a pipeline reactor which are sequentially connected along the waste gas flow direction, and the pipeline reactor is the above-mentioned pipeline reactor.

[0065] Compared with the prior art, the beneficial effects of the process waste gas treatment system provided by the present invention are substantially the same as the beneficial effects of the above-mentioned pipeline reactor, which will not be described in detail here.

[0066] For the structure of the water tank, see Figures 2 to 3 , including a baffle 11, a swirl component and a spray head. The inner cavity of the water tank is divided into a spray water chamber 12 and an exhaust gas chamber along the vertical direction. When the process exhaust gas treatment system is running, the spray water chamber 12 is filled with water. The baffle 11 is arranged in the exhaust gas chamber of the water tank. The baffle 11 divides the exhaust gas chamber into a mixed flow chamber 13 and an exhaust chamber 14 which are sequentially connected along the moving direction of the exhaust gas. The air inlet of the water tank is located at the top of the mixed flow chamber 13, and the air outlet of the water tank is located at the top of the exhaust chamber 14. A connecting hole is opened on the baffle 11, and the connecting hole is located below the baffle 11. When the process exhaust gas treatment system is running, the connecting hole is at least partially located above the water surface contained in the spray water chamber 12, that is, the connecting hole is used as a connecting port between the mixed flow chamber 13 and the exhaust chamber 14. Exemplarily, the three chambers may be arranged as follows: the spray water chamber 12 is located at the bottom, the mixing chamber 13 and the exhaust chamber 14 are located above the spray water chamber 12 , and the mixing chamber 13 is located on the left side of the exhaust chamber 14 .

[0067] The cyclone component is arranged in the exhaust chamber 14, the spray head is arranged in the cyclone component, the top of the cyclone component is connected to the air outlet of the water tank, and the bottom of the cyclone component is closed. In actual application, an opening can be set at the bottom of the cyclone component during processing. When the process waste gas treatment system is running, the liquid level of the spray water chamber 12 is controlled so that the bottom of the cyclone component can be above the bottom of the cyclone component, that is, the bottom of the cyclone component is inserted below the liquid level of the spray water chamber 12, thereby achieving closure, and a cyclone is formed when the waste gas passes through the cyclone component.

[0068] For the structure of the swirl assembly, specifically, it includes at least one first side arc plate 15 and a W-shaped plate 16, see Figure 4 The first side arc plate 15 and the W-shaped plate 16 are both long strips, and the length directions of the two are arranged parallel to each other. The first side arc plate 15 protrudes toward the baffle 11, and the cross-sectional shape of the first side arc plate 15 is a section of an arc protruding toward the baffle 11. The W-shaped plate 16 is located on the side of the first side arc plate 15 away from the baffle 11. The W-shaped plate 16 includes two second side arc plates arranged in parallel and protruding in the direction away from the baffle 11. The shapes and sizes of the two second side arc plates can be set to be exactly the same. The bottom end of the first side arc plate 15 and the bottom end of the second side arc plate have a gap as two openings 151. The openings 151 are for the exhaust gas to flow from the mixing chamber 13 to the W-shaped plate 16. The spray head is arranged in the internal space of the second side arc plate.

[0069] The exhaust gas flowing from the mixed flow chamber 13 to the exhaust chamber 14 through the connecting hole rushes to the side of the first side arc plate 15 at a certain pressure and flow rate, and is divided into two tangential airflows by the side of the first side arc plate 15, and enters the airflow channel formed by the first side arc plate 15 and the W-shaped plate through two openings 151 respectively. Under the guidance of the two second side arc plates, two symmetrical cyclones are formed. The exhaust gas swirls and rises in the space surrounded by the first side arc plate 15 and the W-shaped plate 16, extending the flow path of the exhaust gas. The exhaust gas fully exchanges heat with the first side arc plate 15 and the W-shaped plate 16, further improving the cooling effect on the exhaust gas, so that the overall purification effect of the water tank on the exhaust gas is balanced. Preferably, a spray assembly can also be set in the space surrounded by the first side arc plate 15 and the W-shaped plate 16.

[0070] The cyclone component of this structure adopts the structure of "first side arc plate 15 + W-shaped plate 16", so that the exhaust gas is diverted by the first side arc plate 15, and converges after forming a vortex in the cyclone component, which prolongs the flow path of the exhaust gas, increases the residence time of the exhaust gas in the cyclone component, and enhances the mixing of the spray water sprayed by the spray head and the dust particles in the exhaust gas. The dust particles with larger particle sizes in the exhaust gas collide with the wall surface of the cyclone component under the action of the vortex, and the dust particles are separated from the gas under the action of centrifugal force, thereby reducing the risk of blockage of the exhaust gas treatment equipment and extending the maintenance period of the exhaust gas treatment equipment; at the same time, the exhaust gas is fully in contact with the cyclone component, the contact area is large, and the exhaust gas stays in the cyclone component for a long time, the heat carried by the exhaust gas can be fully transferred to the cyclone component, the spray head provides continuous spray water, and the cyclone component is continuously flushed by the spray water in the water tank, and its heat is also taken away by the spray water, thereby effectively improving the cooling effect of the exhaust gas in the water tank and reducing the cooling energy consumption. At the same time, when the exhaust gas flows through the exhaust chamber 14, the dust particles with larger particle sizes will collide with the first side arc plate 15 and the W-shaped plate 16 under the action of centrifugal force, and separate from the airflow under the action of gravity, and fall into the spray water chamber 12, so as to keep the water tank unobstructed and extend the maintenance period of the water tank and the process exhaust gas treatment system.

[0071] For example, the radius ratio of the first side arc plate 15 to the second side arc plate is 1:1.2-1.8. This arrangement ensures that the exhaust gas leaving the first side arc plate 15 runs into the inner wall of the second side arc plate, and forms a cyclone between the first side arc plate 15 and the W-shaped plate 16 under the guidance of the arc surface.

[0072] In order to remove dust particles with smaller diameters (e.g., dust particles below micron level) in the exhaust gas, the water tank further includes a fogging assembly (e.g., ultrasonic fogger, jet atomizer, or mesh atomizer) disposed on the inner wall of the W-shaped plate 16. In this way, the spray water is sprayed onto the fogging surface of the fogging assembly, and the spray water is broken into small-diameter droplets through high-frequency vibration. The small-diameter droplets combine with the dust particles with smaller diameters in the exhaust gas, and the combination of the two makes it easier to separate from the exhaust gas, thereby removing the small-diameter dust particles of micron level.

[0073] To further extend the exhaust gas flow path, such as Figure 4 As shown, a guide plate 141 is further provided between the baffle plate 11 and the first side arc plate 15. During the operation of the process waste gas treatment system, the bottom of the guide plate 141 extends into the water surface of the spray water chamber 12, and a gap is provided between the top of the guide plate 141 and the top of the water tank. The waste gas flows from the connecting hole into the exhaust chamber 14, flows upward along the guide plate 141, and flows downward from the space surrounded by the guide plate 141 and the first side arc plate 15, extending the flow path of the waste gas in the exhaust chamber 14, and further improving the efficiency of sufficient heat exchange between the waste gas and the water tank, ensuring the cooling effect of the water tank on the waste gas.

[0074] In conjunction with this Figure 4 As shown, the first side arc plate 15 is also provided with connecting plates 152 on both sides, and the connecting plates 152 connect the first side arc plate 15 and the two sides of the W-shaped plate 16, so as to ensure that the exhaust gas can continue to flow downward when it flows from the upper end of the guide plate 141 to the space surrounded by the first side arc plate 15, and will not cause the following situation: the exhaust gas directly flows from the upper part of both sides of the first side arc plate 15 to the vicinity of the W-shaped plate 16 and the water tank outlet, and does not pass through the space surrounded by the first side arc plate 15 and the W-shaped plate 16. The space swirls upward from the bottom to the water tank outlet. This ensures the cooling and dust removal effect of the exhaust gas.

[0075] The present invention also provides a method for treating process waste gas, comprising the following steps:

[0076] Step 1: After thermal decomposition in the reaction chamber and water washing in the spray tower, the waste gas contains a large amount of NOx (the volume percentage of NO is more than 90%) and water vapor, with a temperature of about 30~40℃. This waste gas flows into the physical deliquidation bed; the spray tower sprays water to capture and remove dust with a particle size of more than 1μm.

[0077] Step 2: In the physical deliquidation bed, the larger water vapor is captured and intercepted by the physical deliquidation bed due to inertia. Most of the water vapor is removed efficiently and the exhaust gas humidity is significantly reduced. However, there is still a trace amount of water vapor that will be combined with NO X Together they pass through the gaps in the physical deliquidation bed and enter the chemical catalytic reaction bed; in step 2, the physical deliquidation bed can capture water vapor with a particle size of more than 1 μm and dust with a particle size of less than 1 μm.

[0078] Step 3: In the chemical catalytic reaction bed, ozone, NOx and trace water vapor will mix, diffuse and transfer in the criss-crossing gaps of the bed. Under the action of the active components, water molecules are catalytically decomposed into hydroxyl radicals (·OH) and removed, and O3 is catalytically decomposed into oxygen radicals ·O. Since the oxidation potentials of ·OH and ·O are higher than that of O3 (2.07 eV), their oxidizing properties are significantly stronger than O3. Although the survival time of ·OH and ·O is short, they can still be generated in real time on the surface of the active components and react with NO in real time to oxidize NO, so that NO is converted into NO2 and / or N2O5 that are easily soluble in water, and the exhaust gas after dehumidification and NO removal is obtained. In this step, the trace water vapor is water vapor below the micron level.

[0079] Step 4: The exhaust gas after dehumidification and removal of NO is passed through an alkaline scrubbing tower to remove NO2 and / or N2O5.

[0080] Compared with the prior art, the beneficial effects of the process waste gas treatment method provided by the present invention are substantially the same as the beneficial effects of the above-mentioned process waste gas treatment system, which will not be elaborated here one by one.

[0081] In practical applications, considering that the pipeline reactor can be applied to the existing process waste gas treatment system, the pipeline reactor needs to be connected to the exhaust pipe and the spray tower respectively. Therefore, the following steps are also included before the above step 1:

[0082] Step a: connect one end of the first flange provided with a lining ring to the exhaust gas outlet of the spray tower, and connect the second flange to the exhaust pipe;

[0083] Step b: Connect the ozone inlet hole on the housing to the ozone outlet of the ozone generator through a pipeline.

[0084] In order to ensure efficient removal of NO, the ratio of the amount of ozone delivered to the chemical catalytic reaction bed per unit time to the amount of NO at the exhaust gas outlet through the spray tower is 0.8~1.0.

[0085] Example 1

[0086] In the pipeline reactor of this embodiment, the outer shell is made of stainless steel, and four ozone inlet holes are evenly arranged on the circumference of the outer shell; the first lining material and the second lining material are made of PTFE, the thickness of the first lining material is 3 mm, and the thickness of the second lining material is 1 mm; the thickness of the supporting grid is 5 mm, and the material is PTFE; the physical deliquidation bed is a wire mesh demister with a height of 150 mm, a porosity of 88.3%, and a specific surface area of ​​1300 m 2 / m 3The wire diameter is 0.8mm and the material is PTFE; the chemical catalytic reaction bed is 80mm high and 200mm in diameter. The substrate is a metal wire mesh demister made of stainless steel, the coating is alumina, and the loading capacity is 15%; the active components are manganese oxide and iron oxide, and the mass ratio of the active components to the coating is 8%.

[0087] The above-mentioned pipeline reactor is vertically connected in series between the spray tower of the process waste gas treatment system and the exhaust pipe at the plant end by means of a flange. The ratio of the amount of ozone delivered to the chemical catalytic reaction bed per unit time to the amount of NO at the waste gas outlet of the spray tower is 0.8.

[0088] A temperature sensor, a humidity sensor and a NO detector are respectively installed at the exhaust gas outlet of the spray tower and the exhaust gas inlet of the exhaust pipe. A low-concentration ozone detector is also installed at the exhaust gas inlet of the exhaust pipe. The exhaust gas volume at the exhaust gas inlet of the exhaust pipe is 1000L / min.

[0089] During the exhaust gas treatment process, the humidity, NO content and O3 concentration of the top of the spray tower and the exhaust pipe before and after the pipeline reactor was connected were collected and recorded, see Table 1.

[0090] When the pipeline reactor is not connected, the relative humidity of the exhaust pipe increases compared to the spray tower because the temperature drops and the relative humidity increases slightly. It can be clearly seen from Table 1 that when the pipeline reactor is connected, the relative humidity of the exhaust pipe decreases significantly, indicating that the water vapor content decreases significantly; NO is almost completely converted, and no ozone is detected in the exhaust gas.

[0091] Example 2

[0092] In the pipeline reactor of this embodiment, the outer shell is made of stainless steel, and two ozone inlet holes are evenly arranged on the circumference of the outer shell; the first lining material and the second lining material are made of PTFE, the thickness of the first lining material is 3.2 mm, and the thickness of the second lining material is 1 mm; the thickness of the supporting grid is 5 mm, and the material is PTFE; the physical deliquidation bed is a wire mesh demister with a height of 120 mm, a porosity of 90%, and a specific surface area of ​​1140 m 2 / m 3 The wire diameter is 0.9mm and the material is PTFE; the chemical catalytic reaction bed has a height of 150mm and a diameter of 200mm. The substrate is a metal wire mesh demister made of stainless steel, the coating is alumina, and the loading capacity is 14%; the active components are manganese oxide and iron oxide, and the mass ratio of the active components to the coating is 10%.

[0093] The above pipeline reactor is vertically connected in series between the spray tower and the exhaust pipe of the process waste gas treatment system by flange, and the ratio of the amount of ozone delivered to the chemical catalytic reaction bed per unit time to the amount of NO at the waste gas outlet of the spray tower is 0.9.

[0094] A temperature sensor, a humidity sensor and a NO detector are respectively installed at the exhaust gas outlet of the spray tower and the exhaust gas inlet of the exhaust pipe. A low-concentration ozone detector is also installed at the exhaust gas inlet of the exhaust pipe. The exhaust gas volume at the exhaust gas inlet of the exhaust pipe is 1000L / min.

[0095] During the exhaust gas treatment process, the humidity, NO content, and O3 concentration at the top of the spray tower and the exhaust pipe were collected and recorded, see Table 1.

[0096] Comparative Example 1

[0097] Compared with Example 1, the difference is that no physical liquid removal bed and chemical catalytic reaction bed are arranged in the pipeline reactor, and the other structures and parameters remain unchanged.

[0098] As can be seen from Table 1, compared with Example 1, after connecting to the pipeline reactor, the relative humidity of Comparative Example 1 did not drop significantly, and the NO conversion rate was not high, still at 142.2 mg / m 3 The NO with high concentration is discharged, and the O3 is also completely reacted, and there is secondary pollution. This is because the physical dehydration bed and the chemical catalytic reaction bed are not set in Comparative Example 1, the contact time between NO and O3 is short, the NO conversion efficiency is not high, the O3 has no decomposition catalytic active components and the decomposition is incomplete, and some water vapor will participate in the reaction, but the dehumidification effect cannot be achieved.

[0099] Comparative Example 2

[0100] Compared with Example 1, the difference is that no physical liquid removal bed is provided in the pipeline reactor, and the rest remains unchanged.

[0101] As can be seen from Table 1, compared with Example 1, after connecting to the pipeline reactor, the relative humidity of Comparative Example 2 has decreased, but the dehumidification effect is not as good as that of Example 1, NO cannot be completely converted, and O3 also has some escape. This is because Comparative Example 2 does not have a physical dehydration bed, and the chemical catalytic reaction bed plays the role of a partial defoamer, but the thickness is not enough, and the dehumidification effect is not good. After the high-humidity exhaust gas is sprayed, it directly enters the catalytic reaction bed, and water vapor competes with O3 for adsorption. Part of the active sites are covered by water vapor, the ability to decompose ozone is reduced, the number of active oxygen free radicals generated is attenuated, and NO cannot be completely oxidized and converted.

[0102] Comparative Example 3

[0103] Compared with Example 1, the difference is that the chemical catalytic reaction bed only includes a stainless steel wire mesh demister substrate, does not contain a coating and active components, and the rest remains unchanged.

[0104] As can be seen from Table 1, compared with Example 1, after connecting to the pipeline reactor, the relative humidity of Comparative Example 3 dropped significantly, but the dehumidification effect was not as good as that of Example 1, NO was not completely converted, and a small amount of ozone escaped. This is because Comparative Example 3 does not contain active components and cannot catalyze O3 and H2O to produce more oxidizing free radicals. When the amount of O3 is insufficient, it is difficult for NO to be completely oxidized.

[0105] Comparative Example 4

[0106] Compared with Example 1, the difference is that the chemical catalytic reaction bed only includes a stainless steel wire mesh demister substrate without a coating and active components, the ratio of the amount of ozone delivered to the amount of NO passing is controlled at 1.3, and the rest remains unchanged.

[0107] As can be seen from Table 1, compared with Example 1, after connecting to the pipeline reactor, the relative humidity of Comparative Example 4 decreased significantly, but the dehumidification effect was not as good as that of Example 1, NO was almost completely converted, the ozone outlet concentration was high, and secondary pollution occurred. This is because, compared with Comparative Example 3, Comparative Example 4 input a sufficient amount of O3 to fully oxidize NO, but O3 would have an incomplete reaction, resulting in secondary pollution.

[0108]

[0109] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A process waste gas treatment system, characterized in that: It includes a reaction chamber, a water tank, a spray tower and a pipeline reactor which are sequentially connected along the flow direction of the exhaust gas; The pipeline reactor is used for water and NO in process waste gas X The process waste gas treatment system comprises a shell and a physical deliquescence bed and a chemical catalytic reaction bed sequentially arranged in the shell along the flow direction of the waste gas; the waste gas inlet of the shell is connected to the waste gas outlet of the spray tower of the process waste gas treatment system, and the waste gas discharged from the waste gas outlet of the spray tower contains water vapor and NO X The physical deliquidation bed is used to remove part of the water vapor in the exhaust gas, NO X and the remaining water vapor flows into a chemical catalytic reaction bed; the chemical catalytic reaction bed comprises active components; the chemical catalytic reaction bed is used for catalytic oxidation reaction of ozone, NOx and water vapor; in the chemical catalytic reaction bed, ozone, NOx and water vapor are mixed, diffused and mass transferred in the gap of the chemical catalytic reaction bed layer, under the action of the active components, the water vapor is catalytically decomposed into hydroxyl free radicals, the ozone is catalytically decomposed into oxygen free radicals, the hydroxyl free radicals and oxygen free radicals undergo oxidation reaction with NOx, and NOx is oxidized into NO2 and / or N2O5; The water tank includes a baffle and a swirl assembly, the inner cavity of the water tank is divided into a spray water cavity and an exhaust gas cavity in the vertical direction, the baffle is arranged in the exhaust gas cavity, and the baffle divides the exhaust gas cavity into a mixed flow cavity and an exhaust gas cavity which are sequentially connected along the exhaust gas moving direction; the swirl assembly is arranged in the exhaust gas cavity, the swirl assembly includes at least one first side arc plate and a W-shaped plate, the first side arc plate protrudes toward the baffle, the W-shaped plate is located on a side of the first side arc plate away from the baffle, the W-shaped plate includes two second side arc plates which are arranged in parallel and protrude in the direction away from the baffle, and the bottom end of the first side arc plate and the bottom end of the second side arc plate have a gap as two openings; The exhaust gas flowing from the mixing chamber into the exhaust chamber contacts the side surface of the first side arc plate and is divided into two tangential airflows by the side surface of the first side arc plate. The exhaust gas enters the airflow channel formed by the first side arc plate and the W-shaped plate through two openings respectively, and forms two symmetrical cyclones under the guidance of the two second side arc plates.

2. The process waste gas treatment system according to claim 1, characterized in that: An ozone air inlet is provided on the shell, and an ozone air outlet of the ozone generator is communicated with the ozone air inlet on the shell. The ozone air inlet is located at the lower side of the chemical catalytic reaction bed.

3. The process waste gas treatment system according to claim 1, characterized in that: It also includes a supporting grid and a pressing grid. The supporting grid is located on a side of the physical dehydration bed away from the chemical catalytic reaction bed, and the pressing grid is located on a side of the chemical catalytic reaction bed away from the physical dehydration bed.

4. The process waste gas treatment system according to claim 1, characterized in that: The shell comprises a cylinder and a lining material arranged on the inner wall of the cylinder.

5. The process waste gas treatment system according to claim 4, characterized in that: It also includes a supporting grid, which is located on a side of the physical deliquidation bed away from the chemical catalytic reaction bed; The lining material comprises a first lining material and a second lining material, wherein the second lining material is located between the cylinder and the physical deliquidation bed, and the first lining material is arranged on the inner wall of the cylinder and is located below the second lining material; The supporting grid is located between the first lining material and the second lining material, the outer edge of the upper surface of the supporting grid is in contact with the lower edge of the second lining material, the outer edge of the lower surface of the supporting grid is in contact with the upper edge of the first lining material, and the thickness of the first lining material is greater than that of the second lining material.

6. A process waste gas treatment method, characterized in that: Using the process waste gas treatment system according to any one of claims 1 to 5, the treatment method comprises the following steps: Step 1: The waste gas after thermal decomposition in the reaction chamber and water washing in the spray tower contains nitrogen oxides and water vapor. Part of the water vapor in the waste gas after thermal decomposition in the reaction chamber and water washing in the spray tower is removed in a physical deliquidation bed; Step 2: The remaining water vapor and nitrogen oxides in the exhaust gas pass through the gaps of the physical deliquidation bed and enter the chemical catalytic reaction bed; Step 3: ozone is introduced into the chemical catalytic reaction bed. Under the action of the active components, water vapor is catalytically decomposed into hydroxyl free radicals, and ozone is catalytically decomposed into oxygen free radicals. The hydroxyl free radicals and oxygen free radicals react with NOx on the surface of the active components to convert NOx into NO2 and / or N2O5 that are easily soluble in water, thereby obtaining the exhaust gas after dehumidification and NOx removal; Step 4: The exhaust gas after dehumidification and removal of NOx passes through an alkaline scrubber to remove NO2 and / or N2O5.

7. The process waste gas treatment method according to claim 6, characterized in that: The active component is one or more of manganese oxide, iron oxide, chromium oxide and nickel oxide.

8. The process waste gas treatment method according to claim 6, characterized in that: The chemical catalytic reaction bed comprises a substrate and a coating coated on the exposed outer surface of the substrate, wherein the active component is located in the coating; The coating comprises aluminum oxide; The waste gas after thermal decomposition in the reaction chamber and water washing in the spray tower contains HF acid, which reacts with alumina to generate AlF3 which remains in the coating.

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