Gas treatment system and gas treatment method

Abstract

The embodiment of the present application provides a gas treatment system and a gas treatment method, the gas treatment system is used for treating byproduct gas containing nitric oxide; the gas treatment system comprises: a flow guide device used for guiding the flow of the byproduct gas; a first spraying device used for spraying an acidic denitration liquid to the byproduct gas in the process that the byproduct gas flows in the flow guide device; wherein the denitration liquid contains hydrogen ions and an oxidizing agent. Through the embodiment of the present application, the removal effect of nitric oxide in the byproduct gas is improved, and the content of gaseous nitrogen oxides in the byproduct gas is reduced.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of waste gas treatment, and in particular, to a gas treatment system and a gas treatment method. BACKGROUND

[0002] In a semiconductor manufacturing process, an acid washing process is usually used to remove impurity particles such as metal and organic material on a wafer surface, so as to improve the cleanliness of the wafer surface and to change the physical and chemical properties of the wafer surface to some extent, thereby improving the process precision and process quality of subsequent processes such as photolithography, etching and deposition.

[0003] However, the acid washing process produces a large amount of acid washing waste gas, and the content of acidic components in the acid washing waste gas is high. If the untreated acid washing waste gas is directly discharged into the atmosphere, it is easy to cause pollution such as acid rain, which poses a threat to the environment and human health.

[0004] In order to reduce the content of acidic components in the acid washing waste gas discharged into the atmosphere, in the prior art, the acid washing waste gas is usually subjected to acid-base neutralization treatment by using the "alkali absorption" method before being discharged. However, the "alkali absorption" method is difficult to reduce the content of nitrogen oxides in the acid washing waste gas. SUMMARY

[0005] Therefore, embodiments of the present application provide a gas treatment system and a gas treatment method to reduce the content of nitrogen oxides in the discharged waste gas.

[0006] In one aspect, one embodiment of the present application provides a gas treatment system for treating byproduct gas containing nitric oxide; the gas treatment system comprises: a flow guide device for guiding the flow of the byproduct gas; a first spraying device for spraying an acidic denitration liquid to the byproduct gas during the flow of the byproduct gas in the flow guide device; wherein the denitration liquid contains hydrogen ions and an oxidizing agent.

[0007] Optionally, in the denitration liquid, the hydrogen ions are provided by an acid source; the mass ratio of the acid source to water falls within 1:100-1:10; the mass ratio of the oxidizing agent to water falls within 1:1000 1:100.

[0008] Optionally, in the denitration liquid, the oxidizing agent is one of hydrogen peroxide, potassium permanganate and sodium hypochlorite.

[0009] Optionally, the denitration liquid is made based on a byproduct liquid generated in a semiconductor cleaning process; the byproduct liquid includes sulfuric acid, hydrogen peroxide, water and carbonized impurities.

[0010] Optionally, the gas treatment system further comprises a denitration liquid preparation device connected to the first spraying device, configured to prepare the denitration liquid based on the byproduct liquid; the denitration liquid preparation device comprises a filtering unit configured to filter the carbonized impurities in the byproduct liquid to obtain a filtered liquid; a dilution unit configured to dilute the filtered liquid to obtain a diluted liquid; and an oxidation unit configured to add an oxidizing agent to the diluted liquid to obtain the denitration liquid.

[0011] Optionally, the gas treatment system further comprises a second spraying device configured to spray an alkaline absorption liquid to the byproduct gas during the flowing of the byproduct gas in the flow guide device; wherein the absorption liquid contains hydroxyl ions.

[0012] Optionally, the flow guide device comprises an air inlet configured to introduce the byproduct gas; an air flow channel; and an air outlet configured to flow out the purified gas after gas treatment; the first spraying device and the second spraying device are arranged in the air flow channel; wherein the distance between the first spraying device and the air inlet is less than the distance between the first spraying device and the air outlet; and the distance between the second spraying device and the air inlet is greater than the distance between the second spraying device and the air outlet.

[0013] Optionally, the gas treatment system further comprises a nitrogen oxide sensor arranged between the first spraying device and the second spraying device, configured to detect the composition of nitrogen oxides contained in the gas flowing along the air flow channel.

[0014] In another aspect, one embodiment of the present application provides a gas treatment method for treating byproduct gas containing nitric oxide; the gas treatment method comprises: introducing the byproduct gas into a flow guide device; and spraying an acidic denitration liquid to the byproduct gas by using a first spraying device during the flowing of the byproduct gas in the flow guide device; wherein the denitration liquid contains hydrogen ions and an oxidizing agent.

[0015] Optionally, the gas treatment method further comprises: spraying an alkaline absorption liquid to the byproduct gas by using a second spraying device during the flowing of the byproduct gas in the flow guide device; wherein the absorption liquid contains hydroxyl ions.

[0016] Optionally, the gas treatment method further comprises: detecting the composition of nitrogen oxides contained in the gas flowing along the flow guide device by using a nitrogen oxide sensor to obtain a detection result; and adjusting the ratio between the liquid volume of the denitration liquid and the liquid volume of the absorption liquid according to the detection result.

[0017] In the multiple embodiments provided in the present application, by providing a gas treatment system comprising a flow guide device and a first spraying device, the flow of byproduct gas containing nitric oxide is guided by the flow guide device, and the byproduct gas is sprayed with an acidic denitration liquid by the first spraying device during the flow, the denitration liquid containing hydrogen ions and oxidants, and unexpected effects achieved include that the hydrogen ions and oxidants in the denitration liquid can react with the nitric oxide in the byproduct gas to convert the nitric oxide into nitrate ions that are soluble in water, thereby reducing the content of gaseous nitrogen oxides in the byproduct gas. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used by the embodiments described below will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0019] Figure 1 Structure schematic diagram of an alkali absorption treatment system provided by the related art.

[0020] Figure 2 Structure schematic diagram of a gas treatment system provided by the embodiments of the present application.

[0021] Figure 3 Structure schematic diagram of a denitration liquid preparation device provided by the embodiments of the present application.

[0022] Figure 4 Flow process schematic diagram of preparing a denitration liquid by using a denitration liquid preparation device provided by the embodiments of the present application.

[0023] Figure 5 Flow process schematic diagram of a gas treatment method provided by the embodiments of the present application.

[0024] Figure 6 Comparison schematic diagram of nitric oxide removal rates of a waste gas treatment system provided by the related art and a gas treatment system provided by the embodiments of the present application.

[0025] STRUCTURE REFERENCE DESCRIPTION

[0026] 100, alkali absorption treatment system; 110, spray tower; 120, waste gas inlet; 130, treated gas outlet; 140, spray arm; 150, alkali storage tank; 200, gas treatment system; 210, flow guide device; 211, gas inlet; 212, gas flow channel; 213, gas outlet; 220, first spraying device; 230, denitration liquid preparation device; 231, filtration unit; 2311, by-product liquid storage tank; 2312, first liquid channel; 2313, filtration membrane; 2314, filtered liquid storage tank; 232, dilution unit; 2321, water storage tank; 2322, second liquid channel; 2323, dilution liquid storage tank; 233, oxidation unit; 2331, oxidant storage tank; 2332, third liquid channel; 2333, denitration liquid storage tank; 240, second spraying device; 250, absorption liquid storage tank; 260, nitrogen oxide sensor. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all embodiments of the present application.

[0028] The drawings provided in the embodiments of the present application only schematically illustrate the basic concept of the present application, and only show the components related to the present application in the drawings, not drawn according to the number, shape and size of the components when actually implemented. The shape, number and proportion of each component can be changed when actually implemented, and the component layout form can also be more complex.

[0029] In the description of the embodiments of the present application, it should be understood that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "center" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application, and do not indicate or imply that the indicated device or component must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. The terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include one or more of the features.

[0030] Experimental detection shows that the pickling waste gas discharged in the semiconductor pickling process mainly includes fluorides, sulfuric acid, hydrogen chloride, nitrogen oxides (Nitrogen Oxides, NO xacidic components. To promote regional air pollution control and reduce pollution sources, it is necessary to treat the pickling exhaust gas to reduce the content of acidic components in the pickling exhaust gas. Corresponding to the elements contained in different acidic components in the pickling exhaust gas, the exhaust gas treatment of the pickling exhaust gas includes desulfurization treatment, defluorination treatment, and denitration treatment for removing nitrogen oxides in the exhaust gas.

[0031] After detecting the pickling exhaust gas after denitration treatment, the researchers found that the denitration treatment method provided by the related technology had poor removal effect on nitrogen oxides in the pickling exhaust gas. The specific reasons are analyzed as follows.

[0032] In the pickling exhaust gas, in addition to the nitrogen oxides generated in the pickling process itself, there are also thermal type nitrogen oxides generated by using a combustion type exhaust gas treatment device or a plasma exhaust gas treatment device to treat the pickling exhaust gas. The main component of nitrogen oxides is nitric oxide (NO), which accounts for more than 90%, and the remaining components include nitrogen dioxide (NO2). Since nitrogen dioxide is easily soluble in water, and nitric oxide is difficult to dissolve in water, the key to denitration treatment is to remove nitric oxide. In the related technology, the following three methods are mainly used to remove nitric oxide.

[0033] The first is ammonia selective catalytic reduction (NH3-SCR). Please refer to formula 1. This method can use ammonia and oxygen to reduce nitric oxide to nitrogen under the action of a catalyst at a reaction temperature range of 300°C to 400°C. This method has the advantages of low ammonia escape rate and high denitration efficiency, and can remove 80% to 90% of the nitric oxide in the pickling exhaust gas. However, the catalyst used in this method is toxic and can easily react with other acidic components contained in the pickling exhaust gas to become inactive. In order to achieve safety and effectiveness in the denitration treatment process, a more complex process is required, and the process cost is high.

[0034] 4NH3+4NO+O2 4N2+6H2O Formula 1

[0035] The second is selective non-catalytic reduction (SNCR). Please refer to formula 2. This method can use ammonia and oxygen to reduce nitric oxide to nitrogen under the action of high temperature. This method has the advantages of simple process and low process cost, and can remove 40% to 60% of the nitric oxide in the pickling exhaust gas. However, the required reaction temperature range is 800°C to 1000°C, and the ammonia escape rate is high.

[0036] 4NH3+4NO+O2 4N2+6H2O Formula 2

[0037] The third is the alkali absorption method. Please refer to Equation 3 and Equation 4. This method can convert nitrogen monoxide and nitrogen dioxide into nitrite and nitrate which are easily soluble in water by using alkaline substances. This method has the advantages of simple process, low process cost, no ammonia escape problem, etc., and requires a relatively low reaction temperature range of 10°C~200°C.

[0038] NO + NO2+ O2+ 2OH - 2NO3 - + H2O Equation 3

[0039] 2NO2+ 2OH - NO3 - + NO2 - + H2O Equation 4

[0040] Considering the efficiency and process cost of the above three methods for removing nitrogen monoxide, the ammonia selective catalytic reduction method and the selective non-catalytic reduction method are less used in the actual denitration treatment of pickling waste gas, while the alkali absorption method is more widely used.

[0041] Please refer to Figure 1 . The alkali absorption method can be used to treat the pickling waste gas in the alkali absorption treatment system 100. The specific process includes: introducing the pickling waste gas from the waste gas inlet 120 into the spray tower 110, and controlling the alkali storage tank 150 to provide the alkaline liquid to the spray arm 140 during the movement of the pickling waste gas from the waste gas inlet 120 to the treated gas outlet 130, and the alkaline liquid is atomized and sprayed out by the spray head of the spray arm 140. The nitrogen monoxide in the pickling waste gas contacts and reacts with the alkaline liquid in the spray tower 110 to generate nitrite and nitrate, so that the content of nitrogen monoxide in the treated gas discharged from the treated gas outlet 130 is low.

[0042] However, researchers found that the denitration efficiency of the alkali absorption method is low after detecting the gas actually treated by the alkali absorption method. Even under ideal experimental conditions, the alkali absorption method can only remove 10%~20% of the nitrogen monoxide in the pickling waste gas, and under actual waste gas treatment conditions, the removal rate of nitrogen monoxide in the pickling waste gas by the alkali absorption method tends to be 0. According to the relevant regulations of the state and industry, the emission standard of pickling waste gas is that the concentration of nitrogen oxides should not exceed 50 mg per cubic meter, i.e., NOx≤50 mg / m 3 . In the pickling waste gas without denitration treatment, the concentration of thermal nitrogen oxides can reach 500 mg / m 3 Therefore, it is difficult to make the concentration of nitrogen oxides in the treated gas meet the emission standard of pickling waste gas by using the alkali absorption method to treat the pickling waste gas.

[0043] Therefore, it is necessary to provide a gas treatment system for denitration treatment of pickling waste gas, so that the concentration of nitrogen oxides in the purified gas obtained by denitration treatment can meet the pickling waste gas emission standard.

[0044] Please refer to Figure 2 One embodiment of the present application provides a gas treatment system 200. The gas treatment system 200 can utilize the combined action of chemical absorption and acid-base neutralization reaction to achieve removal of nitrogen oxides, and can be applied to industrial scenarios such as semiconductor manufacturing and thermal power generation that can generate byproduct gas containing nitrogen oxides. The gas treatment system 200 can include a flow guide device 210 and a first spraying device 220.

[0045] In this embodiment, the byproduct gas can be gas discharged in a semiconductor pickling process. In addition to nitrogen monoxide, the byproduct gas can also contain nitrogen dioxide or other nitrogen oxides.

[0046] In this embodiment, the flow guide device 210 can be used to establish a directional airflow channel from the gas inlet end to the gas outlet end, and guide the byproduct gas to flow along the directional airflow channel. Specifically, the flow guide device 210 can include a gas inlet 211 for introducing the byproduct gas, an airflow channel 212, and a gas outlet 213 for discharging the purified gas after gas treatment. To prolong the flow distance of the byproduct gas in the flow guide device 210 and improve the removal efficiency of nitrogen monoxide in the byproduct gas, the airflow channel 212 can include at least two flow guide plates arranged in an alternating manner. Since the byproduct gas contains acidic components, to improve the corrosion resistance of the flow guide device 210, the flow guide device 210 can be made of corrosion-resistant stainless steel or polytetrafluoroethylene.

[0047] In this embodiment, the first spraying device 220 can be arranged in the airflow channel 212 of the flow guide device 210, and can be used to spray acidic denitration liquid to the byproduct gas during the flow of the byproduct gas in the flow guide device 210. Specifically, the first spraying device 220 can include at least two spraying assemblies arranged in an interval along the movement direction of the byproduct gas. To increase the contact surface area of the byproduct gas and the denitration liquid, each spraying assembly can include a plurality of atomizing nozzles. For example, the atomizing nozzles can be pressure-type two-fluid nozzles to achieve micron-level atomization of the denitration liquid.

[0048] In the embodiment, the denitration liquid can convert the nitric oxide into soluble nitrate through an oxidation-reduction reaction. Specifically, the denitration liquid comprises an acid source, an oxidizing agent and water, and the acid source can provide hydrogen ions. The acid source can be sulfuric acid, nitric acid or hydrochloric acid. To reduce the reaction between the acid source and the oxidizing agent in the denitration liquid and improve the stability of the components of the denitration liquid, the acid source in the denitration liquid provided in the embodiment can be sulfuric acid. The mass ratio of the acid source to water can be between 1:100 and 1:10. For example, the mass ratio of the acid source to water can be 1:100, 1:50, 1:20 or 1:10. The mass ratio of the oxidizing agent to water can be between 1:1000 and 1:100. For example, the mass ratio of the oxidizing agent to water can be 1:1000, 1:500, 1:200 or 1:100. 1:100 between. For example, the mass ratio of the oxidizing agent to water can be 1:1000, 1:500, 1:200, 1:100.

[0049] In the embodiment, the oxidizing agent can be one of hydrogen peroxide (H2O2), potassium permanganate (KMnO4) and sodium hypochlorite (NaClO). Specifically, hydrogen peroxide, potassium permanganate or sodium hypochlorite can all achieve oxidation of nitric oxide. However, since hydrogen peroxide is prone to decomposition at a relatively high temperature and has a relatively low reactivity with nitric oxide, and sodium hypochlorite will slowly decompose at room temperature, to improve the oxidation effect of the denitration liquid on nitric oxide, potassium permanganate can be selected as the oxidizing agent in the embodiment.

[0050] Please refer to Formulas 5 to 7. Taking potassium permanganate as the oxidizing agent, the reaction principle of the denitration liquid for converting nitric oxide into nitrate is as follows: nitric oxide reacts with hydrogen ions and permanganate ions, and under the action of hydrogen ions, the oxidation performance of the permanganate ions is enhanced, and the reaction rate between the permanganate ions and nitric oxide is accelerated. In the case that the oxidation capacity of the denitration liquid is relatively strong, for example, in the case that the initial concentrations of the acid source and potassium permanganate are both relatively high before the denitration liquid reacts with nitric oxide, nitric oxide is directly converted into nitrate ions. In the case that the oxidation capacity of the denitration liquid gradually decreases, for example, in the case that the initial concentrations of the acid source and potassium permanganate are both relatively low before the denitration liquid reacts with nitric oxide, or in the case that the concentrations of the acid source and potassium permanganate in the denitration liquid gradually decrease as the reaction proceeds, nitric oxide is converted into nitrogen dioxide which is easily soluble in water, and the nitrogen dioxide dissolves in water and reacts with water to generate nitrate ions and a small amount of nitric oxide.

[0051] 4H + +3MnO4 - +5NO 3Mn 2+ +5NO3 - +2H2O Formula 5

[0052] 2H + +2MnO4 -+ 3NO 3NO2+ 2MnO2+ H2O Equation 6

[0053] 3NO2+ H2O 2HNO3+ NO Equation 7

[0054] In the existing semiconductor cleaning process, the SPM solution (Sulfuric Peroxide Mixture, a mixed solution of concentrated sulfuric acid and hydrogen peroxide) is usually used to wash away the organic matter such as photoresist remaining on the wafer. Specifically, in the process of washing away the remaining organic matter by using the SPM solution, the organic matter is first dehydrated and carbonized by reacting with sulfuric acid in the SPM solution to form solid carbonized impurities. Subsequently, the carbonized impurities are oxidized to gas by reacting with hydrogen peroxide, thereby realizing the removal of the remaining organic matter. However, since the hydrogen peroxide in the SPM solution is unstable and is easy to decompose under high temperature conditions, a small amount of carbonized impurities that have not been oxidized remains in the reaction after-product liquid after the reaction is completed. At the same time, the reaction also produces a large amount of water, which causes the SPM solution to be diluted.

[0055] Therefore, with the continuous increase of the production batch of semiconductors, a large amount of mixed liquid of sulfuric acid, hydrogen peroxide, water and carbonized impurities, i.e., the after-product liquid, will be produced in the cleaning process, in which the concentration of sulfuric acid can reach 60% to 80%, and the content of carbonized impurities is relatively small. In order to reduce environmental pollution, the after-product liquid needs to be treated for harmless discharge, but since the concentration of sulfuric acid in the after-product liquid is high, the treatment of the after-product liquid is difficult and the treatment cost is high. According to statistics, the global use of SPM solution has reached more than 1.8 million tons, and accordingly, there is a large amount of after-product liquid that needs to be treated for harmless discharge.

[0056] Please refer to Figures 2 to 4 together. In order to realize "waste treatment with waste", while treating the after-product liquid for harmless discharge, the sulfuric acid in the after-product liquid is used. In some embodiments, the gas treatment system 200 can further include a denitration liquid preparation device 230 connected with the first spraying device 220. The denitration liquid preparation device 230 can be used to prepare a denitration liquid based on the after-product liquid, and provide the denitration liquid to the first spraying device 220.

[0057] In the embodiment, the denitration liquid preparation device 230 can include a filtering unit 231, a dilution unit 232. Specifically, to reduce impurities in the denitration liquid and improve the reaction rate of the denitration liquid and the byproduct gas, the filtering unit 231 can be used to filter carbonized impurities in the byproduct liquid to obtain a filtered liquid. To improve the safety of subsequent denitration processing and save process cost, the dilution unit 232 can be used to dilute the filtered liquid after the filtered liquid is obtained to obtain a diluted liquid. The filtering unit 231 can include a byproduct liquid storage tank 2311, a first liquid channel 2312, a filtering membrane 2313, and a filtered liquid storage tank 2314. The dilution unit 232 can include a water storage tank 2321, a second liquid channel 2322, and a diluted liquid storage tank 2323. The first liquid channel 2312 and the second liquid channel 2322 can be provided with a metering pump. The filtering membrane 2313 can be made of polytetrafluoroethylene, and the filtering precision can reach 1 μm.

[0058] To maintain the stability of the oxidizing agent in the denitration liquid and improve the reaction activity between the oxidizing agent and nitric oxide in the denitration liquid, the denitration liquid preparation device 230 can further include an oxidation unit 233 in the embodiment. The oxidation unit 233 can be used to add an oxidizing agent to the diluted liquid to obtain a denitration liquid. Specifically, the oxidation unit 233 can include an oxidizing agent storage tank 2331, a third liquid channel 2332, and a denitration liquid storage tank 2333. The third liquid channel 2332 can be provided with a metering pump. The denitration liquid storage tank 2333 can be connected with the first spraying device 220.

[0059] The specific process of preparing the denitration liquid by using the denitration liquid preparation device 230 is as follows.

[0060] First, the metering pump on the first liquid channel 2312 is opened, so that the byproduct liquid stored in the byproduct liquid storage tank 2311 flows into the filtered liquid storage tank 2314 through the filtering membrane 2313, the solid organic impurities in the byproduct liquid are filtered out by using the filtering membrane 2313, and a filtered liquid is obtained.

[0061] Then, the metering pump on the second liquid channel 2322 is opened, so that the filtered liquid stored in the filtered liquid storage tank 2314 and the water in the water storage tank 2321 flow into the diluted liquid storage tank 2323 to dilute the filtered liquid, and a diluted liquid is obtained. The concentration of sulfuric acid in the diluted liquid is lower than that in the filtered liquid.

[0062] Subsequently, the metering pump on the third liquid channel 2332 is opened, so that the diluted liquid stored in the diluted liquid storage tank 2323 and the oxidizing agent liquid stored in the oxidizing agent storage tank 2331 flow into the denitration liquid storage tank 2333 to add the oxidizing agent to the diluted liquid, and a denitration liquid is obtained.

[0063] The researchers found that by spraying the byproduct gas with the acidic denitration liquid, about 80% of the nitrogen oxides in the byproduct gas can be removed.

[0064] Please continue to refer to Figure 2 To further reduce the content of nitrogen oxides in the byproduct gas, the gas treatment system 200 can further include a second spraying device 240.

[0065] In this embodiment, the second spraying device 240 can be arranged in the airflow channel 212 of the flow guide device 210, and can be used to spray the byproduct gas with the alkaline absorption liquid during the flow of the byproduct gas in the flow guide device 210, so as to absorb the unremoved nitrogen oxides by the absorption liquid. Specifically, the second spraying device 240 can include at least two spraying assemblies arranged at intervals along the movement direction of the byproduct gas. To increase the contact surface area of the byproduct gas and the absorption liquid, each spraying assembly can include a plurality of atomizing nozzles. For example, the atomizing nozzles can adopt pressure type double fluid nozzles to achieve micron-level atomization of the absorption liquid.

[0066] In this embodiment, the absorption liquid contains hydroxyl ions. For example, the absorption liquid can be a 10% sodium hydroxide (NaOH) solution.

[0067] To improve the removal effect of nitrogen oxides in the byproduct gas, in this embodiment, the distance between the first spraying device 220 and the gas inlet 211 can be less than the distance between the first spraying device 220 and the gas outlet 213, and the distance between the second spraying device 240 and the gas inlet 211 can be greater than the distance between the second spraying device 240 and the gas outlet 213. Specifically, along the movement direction of the byproduct gas in the flow guide device 210, the byproduct gas can flow through the first spraying device 220 and the second spraying device 240 in turn, and be converted into purified gas.

[0068] In this embodiment, the reaction principle of the absorption liquid absorbing unremoved nitrogen oxides is similar to that of the alkali absorption method in the related art, which will not be described here.

[0069] The researchers found in the actual gas treatment process that as the amount of the denitration liquid sprayed by the first spraying device 220 decreases, the content of nitrogen dioxide in the gas flowing through the first spraying device 220 increases, and the content of the nitrate generated by the reaction between the byproduct gas and the denitration liquid decreases. The increased nitrogen dioxide can be absorbed by the absorption liquid in the subsequent process of the gas flowing through the second spraying device 240. Therefore, in order to reduce the use amount of the denitration liquid while maintaining the denitration effect on the byproduct gas and reducing the process cost, the gas treatment system 200 in the embodiment can further include a nitrogen oxide sensor 260 for detecting the composition of the nitrogen oxides contained in the gas flowing along the airflow channel 212. Specifically, the detection result of the nitrogen oxide sensor 260 can reflect the content of nitrogen monoxide and nitrogen dioxide contained in the gas flowing along the airflow channel 212, so that the ratio between the amount of the denitration liquid and the amount of the absorption liquid can be adjusted according to the detection result. In order to improve the control ability of the liquid amount ratio of the sprayed denitration liquid and absorption liquid, the nitrogen oxide sensor 260 can be arranged between the first spraying device 220 and the second spraying device 240. For example, in the movement direction of the byproduct gas, the distance between the nitrogen oxide sensor 260 and the first spraying device 220 can be less than the distance between the nitrogen oxide sensor 260 and the second spraying device 240.

[0070] Referring to Figure 5 Another embodiment of the present application provides a gas treatment method, which can be used for treating byproduct gas containing nitrogen monoxide. The gas treatment method can be implemented by the gas treatment system described in the above embodiments. The gas treatment method can include steps S310 and S320.

[0071] S310: introducing the byproduct gas into the flow guide device.

[0072] S320: spraying the acidic denitration liquid to the byproduct gas by using the first spraying device during the flowing process of the byproduct gas in the flow guide device; wherein the denitration liquid contains hydrogen ions and oxidants.

[0073] In order to improve the removal effect of the nitrogen oxides in the byproduct gas and further reduce the content of the nitrogen oxides in the byproduct gas, the gas treatment method in the embodiment can further include: spraying the alkaline absorption liquid to the byproduct gas by using the second spraying device during the flowing process of the byproduct gas in the flow guide device; wherein the absorption liquid contains hydroxide ions.

[0074] To reduce the use of the denitration liquid while maintaining the denitration effect on the byproduct gas, and save the process cost, in the embodiment, the gas treatment method can further include: detecting the composition of nitrogen oxides contained in the gas flowing along the flow guide device by using a nitrogen oxide sensor to obtain a detection result; and adjusting the ratio between the liquid amount of the denitration liquid and the liquid amount of the absorption liquid according to the detection result. Specifically, for example, the denitration liquid preset liquid amount and the absorption liquid preset liquid amount can be determined based on historical experimental data, and then the control variable method is used to keep the liquid amount of the sprayed absorption liquid unchanged at the absorption liquid preset liquid amount, and gradually reduce the liquid amount of the sprayed denitration liquid from the denitration liquid preset liquid amount. The content of nitrogen dioxide in the gas flowing through the first spraying device is detected by using the nitrogen oxide sensor, and the content of nitrogen oxides in the purified gas discharged from the gas outlet is detected. In the case of an increase in the content of nitrogen oxides in the purified gas, the liquid amount of the corresponding denitration liquid and the liquid amount of the absorption liquid are taken as the liquid amount ratio threshold.

[0075] Please refer to Figure 6 . The researchers compared the treated gas obtained after the denitration treatment by using the "alkali absorption" method provided by the related art with the purified gas obtained after the denitration treatment by using the gas treatment method provided by the embodiment. Specifically, based on laboratory conditions, the researchers used an experimental device simulating actual denitration treatment to make the byproduct gas flow only through the alkaline absorption liquid, or to make the byproduct gas flow through the acidic denitration liquid and the alkaline absorption liquid in sequence, and then used a flue gas analyzer to detect the gas flowing only through the alkaline absorption liquid and the gas flowing through the acidic denitration liquid and the alkaline absorption liquid in sequence, respectively. The detection results show that by making the byproduct gas flow through the alkaline absorption liquid, 7.4% of the nitric oxide in the byproduct gas can be removed, and by making the byproduct gas flow through the acidic denitration liquid and the alkaline absorption liquid in sequence, 96.7% of the nitric oxide in the byproduct gas can be removed. By comparing the nitric oxide removal rates of the two methods, it can be seen that compared with the "alkali absorption" method in the related art, the application of the gas treatment method provided by the application to actual denitration treatment can greatly improve the removal effect of nitric oxide in the byproduct gas.

[0076] The other technical effects of the gas treatment method described in the above embodiments can be explained by referring to other embodiments of the application, which will not be described here.

[0077] In the gas treatment system and the gas treatment method provided by the embodiment of the present application, the byproduct gas containing nitric oxide is guided by the flow guide device, and the byproduct gas is sprayed with the acidic denitration liquid containing hydrogen ions and oxidants by the first spraying device during the flow process, and unexpected effects are achieved, including that the hydrogen ions and the oxidants in the denitration liquid can react with the nitric oxide in the byproduct gas to convert the nitric oxide into nitrate ions that are soluble in water, thereby improving the removal effect of the nitric oxide in the byproduct gas and reducing the content of gaseous nitrogen oxides in the byproduct gas, and the denitration liquid is made of the byproduct liquid generated in the semiconductor cleaning process, "waste treatment with waste" is achieved, the harmless treatment difficulty of the byproduct gas and the byproduct liquid is reduced, and the process cost is saved.

[0078] It can be understood that the specific examples in the present application are only to help those skilled in the art to better understand the embodiments of the present application, and not to limit the scope of the present application.

[0079] It can be understood that in various embodiments in the present application, the size of the serial number of each process does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0080] It can be understood that the various embodiments described in the present application can be implemented alone or in combination, and the embodiments of the present application do not limit this.

[0081] Unless otherwise specified, all technical and scientific terms used in the embodiments of the present application have the same meanings as those commonly understood by those skilled in the art of the present application. The terms used in the present application are only for the purpose of describing the specific embodiments and are not intended to limit the scope of the present application. The term "and / or" used in the present application includes any and all combinations of one or more related listed items. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0082] In several embodiments provided in the present application, it should be understood that the disclosed gas treatment system can be implemented in other ways. For example, the embodiments of the gas treatment system described above are only illustrative.

[0083] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A gas processing system, characterized in that, The gas processing system is used to process byproduct gases containing nitric oxide; The gas processing system includes: A flow guiding device is used to guide the flow of the by-product gas; the flow guiding device includes: an air inlet for introducing the by-product gas; an airflow channel; and an air outlet for discharging purified gas after gas treatment. A first spraying device is used to spray an acidic denitrification liquid onto the by-product gas as it flows within the flow guiding device. The first spraying device is disposed within the airflow channel. The distance between the first spraying device and the air inlet is less than the distance between the first spraying device and the air outlet. The denitrification liquid contains hydrogen ions and an oxidant. The denitrification liquid is based on a by-product liquid generated during a semiconductor cleaning process. The by-product liquid includes sulfuric acid, hydrogen peroxide, water, and carbonized impurities. The gas processing system also includes: A second spraying device is used to spray an alkaline absorbing liquid onto the by-product gas as it flows within the flow guiding device; the second spraying device is disposed within the airflow channel; the distance between the second spraying device and the air inlet is greater than the distance between the second spraying device and the air outlet; wherein the absorbing liquid contains hydroxide ions; A nitrogen oxide sensor is disposed between the first spray device and the second spray device for detecting the nitrogen oxide composition of the gas flowing along the airflow channel; A denitrification liquid preparation device connected to the first spraying device is used to prepare the denitrification liquid based on the by-product liquid; the denitrification liquid preparation device includes: A filtration unit is used to filter the carbonized impurities in the byproduct liquid to obtain a filtered liquid; A dilution unit is used to dilute the filtered liquid to obtain a diluted liquid; An oxidation unit is used to add an oxidant to the diluted liquid to obtain the denitrified liquid.

2. The gas processing system according to claim 1, characterized in that, In the denitrification liquid, the hydrogen ions are provided by an acid source; the mass ratio of the acid source to water falls between 1:100 and 1:10; the mass ratio of the oxidant to water falls between 1:1000. Between 1:

100.

3. The gas processing system according to claim 1, characterized in that, In the denitrification liquid, the oxidant is one of hydrogen peroxide, potassium permanganate, and sodium hypochlorite.

4. A gas treatment method, characterized in that, Applied to the gas treatment system as described in any one of claims 1-3; the gas treatment method is used to treat byproduct gases containing nitric oxide; the gas treatment method includes: The byproduct gas is introduced into the flow guide device; During the flow of the byproduct gas within the guiding device, an acidic denitrification liquid is sprayed onto the byproduct gas using a first spraying device; wherein the denitrification liquid contains hydrogen ions and an oxidant.

5. The gas treatment method according to claim 4, characterized in that, The gas treatment method further includes: During the flow of the byproduct gas within the guiding device, an alkaline absorption liquid is sprayed onto the byproduct gas using a second spraying device; wherein the absorption liquid contains hydroxide ions.

6. The gas treatment method according to claim 5, characterized in that, The gas treatment method further includes: The composition of nitrogen oxides in the gas flowing along the flow guide device is detected using a nitrogen oxide sensor, and the detection results are obtained. Adjust the ratio between the volume of the denitrification liquid and the volume of the absorption liquid according to the test results.

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