Method for removing carbon monoxide from flue gas by plasma discharge coupled catalytic oxidation

Abstract

The application discloses a method for removing carbon monoxide in flue gas by plasma discharge coupling catalytic oxidation. The method is that a copper-manganese co-oxide catalyst with oxygen vacancies on the surface is filled in a discharge cavity of a plasma reactor, and then flue gas is introduced into the discharge cavity to perform discharge catalytic oxidation to remove carbon monoxide in the flue gas. The method realizes perfect coupling of the advantages of plasma discharge and metal oxide catalytic oxidation, greatly improves the selectivity and high efficiency of the carbon monoxide oxidation reaction in the flue gas, prolongs the service life of the catalyst and the discharge equipment, reduces the energy consumption and treatment cost of the flue gas treatment, and realizes clean production.

Description

Technical Field

[0001] This invention relates to a method for removing carbon monoxide from flue gas, specifically a method for removing carbon monoxide from flue gas by plasma discharge coupled catalytic oxidation, belonging to the field of flue gas treatment technology. Background Technology

[0002] Carbon monoxide poses a serious threat to the environment and human health, and its emissions urgently need to be reduced to meet emission requirements. Currently, metal catalyst catalytic oxidation processes are widely used in flue gas treatment in industries such as iron and steel metallurgy and thermal power generation due to their advantages of high carbon monoxide removal efficiency, short process flow, low raw material cost, and small footprint. However, due to the high cost and scarcity of raw materials, they have been gradually replaced by transition metal catalysts in recent years, such as copper-based catalysts. However, copper-based catalysts suffer from insufficient catalytic activity at 200℃ and poor water resistance, severely restricting their widespread application in industrial fields.

[0003] To overcome these shortcomings of metal catalysts, scientists have made numerous attempts to improve traditional processes to enhance the reactivity and stability of metal catalysts in low-temperature and humid environments. Among these, plasma discharge oxidation technology has proven to have development potential. Currently, research into the principles of plasma discharge oxidation is deepening, and projects using plasma to improve the treatment of carbon monoxide in flue gas are increasing.

[0004] The principle of plasma discharge oxidation is to use a high-voltage electric field to accelerate free electrons in the air, causing them to collide with gas macromolecules at high speed. The gas macromolecules are ionized by these collisions, producing various free radicals with oxidizing activity. Because the reaction mechanism of plasma mainly relies on the collisions between active groups in space, its reaction selectivity is poor; components with higher concentrations in the flue gas are often more likely to react. Therefore, using plasma discharge oxidation alone to oxidize flue gas produces a large number of byproducts, such as nitrogen molecules being oxidized by free radical collisions to form nitrogen oxides. Carbon monoxide is not a major component in flue gas; therefore, plasma has poor selectivity for carbon monoxide and produces a large amount of nitrogen oxide byproducts, which not only increases the burden on subsequent selective catalytic reduction (SCR) denitrification processes but also reduces energy efficiency. This limits the widespread application of plasma discharge technology.

[0005] Therefore, the current application scope of plasma discharge technology is mainly limited to the oxidative degradation of volatile organic compounds (mainly aliphatic, aromatic, oxygen-containing hydrocarbons, chlorinated hydrocarbons, and nitrogen-containing hydrocarbons). Because the volume of organic macromolecules is much larger than nitrogen gas, they are more likely to undergo decomposition reactions upon impact, and are difficult to repolymerize; the overall reaction can be considered irreversible. However, regarding the application of plasma discharge technology in flue gas treatment, since nitrogen is the main component of flue gas, it is more prone to side reactions due to free radical collisions. How to suppress side reactions and improve the selectivity of reactive free radicals for carbon monoxide remains a key factor restricting the development and application of this technology. Summary of the Invention

[0006] To address the technical problem of low selectivity in carbon monoxide reaction during plasma discharge processes in flue gas treatment, this invention aims to provide a method for removing carbon monoxide from flue gas by coupling plasma discharge with catalytic oxidation. This method perfectly combines the advantages of plasma discharge and metal oxide catalytic oxidation, significantly improving the selectivity and efficiency of carbon monoxide reaction in flue gas. Furthermore, this method simultaneously extends the service life of the metal catalyst and the discharge equipment, reduces energy consumption and treatment costs in flue gas treatment, and achieves cleaner production.

[0007] To achieve the above-mentioned technical objectives, the present invention provides a method for removing carbon monoxide from flue gas by plasma discharge coupled catalytic oxidation. The method involves filling the discharge chamber of a plasma reactor with a copper-manganese cooxide catalyst containing oxygen vacancies on its surface, and then introducing flue gas into the discharge chamber for discharge catalytic oxidation to remove the carbon monoxide component from the flue gas.

[0008] The key to this invention lies in placing a copper-manganese cooxide catalyst with oxygen vacancies within the discharge chamber of a plasma discharge reactor. The oxygen vacancies on the catalyst surface capture free oxygen-containing groups generated by ionization, thus anchoring the active oxygen groups to the catalyst surface for stability. Simultaneously, the cuprous ions on the catalyst surface are typical carbon monoxide adsorption sites, readily adsorbing carbon monoxide and forming common composite structures. Carbon monoxide is adsorbed by the copper-manganese cooxide catalyst and undergoes oxidation with the adsorbed active oxygen-containing groups, significantly improving the selectivity of the active oxygen-containing groups for carbon monoxide oxidation. Furthermore, the adsorption selectivity of the copper-manganese cooxide catalyst surface for carbon monoxide is much higher than for other gases such as nitrogen, making it difficult for nitrogen to adsorb onto the surface and combine with active oxygen-containing groups to form nitrogen oxide byproducts, thereby reducing the content of nitrogen oxide byproducts and improving energy efficiency. Moreover, using active oxygen-containing groups generated by plasma discharge instead of oxygen as the oxygen source for carbon monoxide oxidation results in a lower reaction energy barrier, increasing the oxidation rate of carbon monoxide in low-temperature environments. In addition, the adsorption strength of water vapor ionization products (mainly hydroxyl groups) on the surface of copper-manganese cooxide catalysts also decreases due to space discharge, reducing their poisoning effect and thus improving the water resistance of copper-manganese cooxide catalysts.

[0009] As a preferred embodiment, the copper-manganese cooxide catalyst is prepared by the following method: a solution containing manganese ions and copper ions is subjected to coprecipitation to obtain a copper-manganese coprecipitate, which is then dried, calcined in air, and crushed to obtain the final product.

[0010] Alternatively, the copper-manganese cooxide catalyst can be prepared by calcining a manganese salt to obtain manganese oxide, soaking the manganese oxide in an acid solution containing copper ions, drying the mixed solution, roasting the resulting solid in air, and then crushing it to obtain the catalyst.

[0011] The impregnation method and coprecipitation method involved in this invention are two common methods for preparing copper-manganese coprecipitates in the prior art. The key to this invention lies in the calcination process of the copper-manganese coprecipitate. The calcination process allows the copper-manganese coprecipitate to be fully converted into copper-manganese cooxide and generates surface vacancies. Among them, the coprecipitation method is the simplest and most commonly used method for preparing copper-manganese coprecipitates. The specific steps are as follows: soluble salts of copper and manganese are mixed and dissolved in a solvent. The molar ratio of Mn / Cu in the copper-manganese cooxide catalyst is adjusted by controlling the concentration of soluble salts of copper and manganese in the mixed solution. The soluble salts of copper and manganese should have high solubility, for example, nitrates are used. Then, a precipitant is added to initiate coprecipitation, and the precipitate product is the copper-manganese coprecipitate. The precipitant is mainly an alkali, and the simultaneous precipitation of copper and manganese is caused by adjusting the pH of the solution. There are no strict requirements on the type of alkali used, such as concentrated ammonia. The formation of copper-manganese coprecipitates mainly involves three stages: supersaturation, nucleation, and growth. After aging, filtration, and washing, copper-manganese coprecipitates with amorphous or crystalline phases can be obtained. The copper-manganese coprecipitate is further dried and calcined to obtain a copper-manganese cooxide catalyst. Drying aims to remove adsorbed free water molecules from the catalyst surface; therefore, it is typically carried out at around 120°C for more than 12 hours. Calcination mainly decomposes the water of crystallization in the copper-manganese coprecipitate; therefore, it is typically carried out at temperatures above 300°C for 1–2 hours. Excessive calcination temperature or time can easily lead to recrystallization on the catalyst surface, thereby eliminating surface defects and reducing the number of active sites. The large solid particles after calcination are then crushed to obtain catalyst particles of the desired diameter for subsequent industrial applications in flue gas treatment. In addition, impregnation is also a common method for preparing copper-manganese coprecipitates. Typically, one of the metal oxide particles is first obtained; for example, manganese carbonate is decomposed at high temperature to produce manganese oxide particles. Then, a surface impregnation method is used to adsorb copper ions onto the surface of the manganese oxide solid particles, and through ion exchange, copper ions fully contact the manganese oxide on the surface of the manganese oxide support, finally forming an amorphous copper-manganese coprecipitate on the surface. The specific steps are as follows: Manganese oxide particles are immersed in a copper nitrate solution, with an appropriate amount of nitric acid added as a promoter. Copper ions in the solution are adsorbed onto the surface of the manganese oxide particles under the influence of Coulomb's force. Under the promoting effect of acid, ion exchange occurs between the copper ions and the charged manganese oxide particles, resulting in the replacement of some manganese ions on the surface of the solid manganese oxide with copper ions. Therefore, the loading of copper oxide on the surface can be adjusted by changing the concentration of the nitric acid solution. The calculated amount of copper nitrate is mixed evenly with nitric acid according to production requirements. Then, a MnO2 support is added under stirring. The solution is continuously dried at approximately 120°C for 12 hours to obtain a copper-manganese coprecipitate, which is then calcined at above 300°C for 1–2 hours.

[0012] As a preferred embodiment, the acid concentration in the copper-containing acid solution is 3–7 mol / L.

[0013] As a preferred embodiment, the molar ratio of Mn / Cu in the copper-manganese cooxide catalyst is 2.5:1 to 4:1. The molar ratio of Mn / Cu can alter the catalyst activity, and a Mn / Cu molar ratio of 2.5:1 to 4:1 exhibits optimal discharge matching. During the CO oxidation reaction, manganese oxides act as carriers for active oxygen-containing groups, while copper oxides provide adsorption sites for CO on the surface. Therefore, when the Mn ratio is too high, the surface of the copper-manganese cooxide catalyst lacks reaction sites that can stably adsorb CO gas molecules, thus affecting the removal efficiency of CO components from flue gas. Conversely, when the Mn ratio is too low, the oxidation reaction on the surface of the copper-manganese cooxide catalyst is limited by insufficient supply of active oxygen. Furthermore, oxygen vacancies can form around low-valence Mn ions, and O2 preferentially binds to these vacancies to form active oxygen functional groups that participate in CO surface oxidation. A low Mn ratio means fewer oxygen vacancies available for oxidation, similarly affecting the catalyst efficiency.

[0014] As a preferred embodiment, the calcination conditions are: temperature 300–450℃, time 1–2 hours. Calcination conditions primarily affect the solid surface area and phase composition. Under the preferred calcination conditions, the resulting copper-manganese cooxide catalyst exhibits high internal electron mobility and good electrical conductivity. If calcination is carried out at higher temperatures, the copper-manganese cooxide catalyst will undergo lattice defect elimination, such as oxygen vacancies, due to phase rearrangement, leading to a decrease in catalytic selectivity. Conversely, if the calcination temperature is too low, the metal hydroxide is difficult to dehydrate and form, making it impossible to obtain a copper-manganese cooxide catalyst with a high specific surface area and rich in oxygen vacancies. The most preferred calcination temperature is 350–400℃.

[0015] As a preferred embodiment, the copper-manganese cooxide catalyst has a specific surface area of ​​180–240 m². 2 / g, bulk density is 0.65~0.75g / cm³ 3 Adjusting product parameters allows copper-manganese cooxide catalysts with specific surface area and bulk density controlled within a certain range to achieve better coupling discharge.

[0016] As a preferred embodiment, the amount of copper-manganese cooxide catalyst filling the discharge chamber is proportional to the flow rate of the flue gas, and the mass space velocity of the flue gas is 25–35 m / s. 3 / (h*kg).

[0017] As a preferred embodiment, the carbon monoxide concentration in the flue gas is 8000–10000 ppm. The flue gas is a byproduct emitted at the end of the sintering process in a steel plant. After plasma discharge coupled catalytic oxidation, the carbon monoxide concentration in the flue gas can be reduced to below 1000 ppm, with a carbon monoxide removal efficiency exceeding 90%.

[0018] As a preferred embodiment, the discharge conditions are: voltage of 10-30kV and discharge frequency of 1-10kHz.

[0019] This invention removes carbon monoxide from flue gas through plasma discharge coupled with catalytic oxidation, achieving a carbon monoxide conversion rate of over 90% and a selectivity of over 75%.

[0020] The carbon monoxide oxidation process of this invention is an exothermic reaction, which can heat the flue gas during the carbon monoxide purification process, increase the initial temperature of the flue gas entering the selective catalytic reduction denitrification stage, increase the selective catalytic reduction denitrification rate, and reduce the energy consumption of the flue gas preheating stage.

[0021] This invention utilizes plasma discharge coupled with catalytic oxidation to remove carbon monoxide from flue gas, and modifies the chemical reaction pathways of carbon monoxide removal from flue gas by plasma discharge alone, as follows: Figure 2 As shown, if only plasma discharge is used, the highly reactive oxygen generated by the plasma can react simultaneously with oxygen to produce ozone, with nitrogen to produce nitrogen oxides, and with carbon monoxide to produce carbon dioxide, resulting in a reaction lacking high selectivity. However, after plasma discharge is coupled with catalytic oxidation, the selectivity of the carbon monoxide reaction increases due to the selective adsorption of carbon monoxide by the copper-manganese cooxide catalyst and the binding effect of oxygen vacancies on reactive oxygen. Simultaneously, the copper-manganese cooxide catalyst particles can act as conductors, improving discharge efficiency and discharge space uniformity, and protecting the electrode plates from damage caused by localized discharge disturbances.

[0022] Compared with the prior art, the beneficial technical effects of the technical solution of the present invention are as follows:

[0023] Currently, plasma discharge technology suffers from poor reaction selectivity, and using plasma discharge alone to oxidize flue gas produces a large amount of nitrogen oxide byproducts. Furthermore, solid metal catalysts have limitations in low-temperature reactivity and hydrophobicity, making it difficult to meet the industrial demands for efficient carbon monoxide treatment. The method for removing carbon monoxide from flue gas by plasma discharge coupled with catalytic oxidation, provided by this invention, perfectly combines the advantages of both plasma discharge and metal oxide catalytic oxidation processes. This significantly improves the selectivity and efficiency of carbon monoxide oxidation in flue gas and can be used for the oxidative removal of carbon monoxide components in flue gas from the steel industry. Compared to using solid catalysis or plasma discharge oxidation alone, this coupling of the two processes reduces energy consumption in flue gas treatment, increases carbon monoxide removal efficiency, extends the service life of catalysts and discharge equipment, reduces flue gas treatment costs, and achieves cleaner production.

[0024] The present invention provides a method for removing carbon monoxide from flue gas using plasma discharge coupled with catalytic oxidation. This method employs a transition metal oxide catalyst, which, compared to precious metal catalysts, is readily available and less expensive. Furthermore, the transition metal oxide catalyst's adaptability to water vapor in the flue gas is enhanced after the plasma discharge process, reducing the toxic effects of water vapor. In addition, the transition metal oxide catalyst particles act as conductors, improving plasma discharge efficiency and discharge space uniformity, and protecting the electrode plates from damage due to localized discharge disturbances. Attached Figure Description

[0025] Figure 1 The copper-manganese cooxide catalyst prepared in Example 1.

[0026] Figure 2 The chemical reaction pathways for removing carbon monoxide from flue gas by plasma discharge coupled with catalytic oxidation are different from those for removing carbon monoxide from flue gas by plasma discharge alone.

[0027] Figure 3 This is a process flow diagram for the removal of carbon monoxide from flue gas by plasma discharge coupled with catalytic oxidation. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] A steel plant filled the discharge chamber of non-thermal plasma with a copper-manganese cooxide catalyst, with a filling amount of approximately 180g, at a depth of 35m. 3 / h flue gas flow rate corresponds to 1kg catalyst content, used to improve the catalytic activity of carbon monoxide oxidation.

[0031] This copper-manganese cooxide catalyst was prepared by impregnation. The MnCO3 precursor was continuously calcined in air to form manganese oxide (MnO). x The product was selected as the support for the preparation of copper-manganese cooxide catalyst (CuO / MnO2) by the initial wet impregnation method. To compare the effect of calcination temperature on the catalytic performance of the copper-manganese cooxide catalyst, the calcination temperatures were adjusted to 300, 350, 400, 450, 500, and 600 °C, with a calcination time of 2 h. The corresponding products were denoted as MnO2. x -300, MnO x -350, MnO x -400, MnOx -450, MnO x -500 and MnO x -600. Structural characterization and catalytic activity evaluation were conducted: the activity of manganese oxide calcined at different temperatures was compared by measuring the temperature at which CO conversion reached 50%. MnO x -300, MnO x -350, MnO x -400 and MnO x -450 exhibited similar catalytic performance, with 50% CO conversion corresponding to temperatures of 126, 110, 133, and 154 °C, respectively. MnO... x -500 and MnO x -600 exhibited poor catalytic activity, with 50% CO conversion occurring at temperatures above 190℃. MnO x -350 exhibits the characteristics of MnO2 and the best catalytic performance for CO oxidation, therefore the calcination temperature was ultimately locked at 350℃.

[0032] Subsequently, industrial-grade >98% solid copper nitrate Cu(NO3)2 was weighed according to calculations to prepare a 0.25 mol / L aqueous solution. 5 mol / L dilute nitric acid was mixed with the copper nitrate solution, controlling the amounts of both solutions to achieve a copper nitrate solution to dilute nitric acid mass ratio of 2:3. 2 kg of copper nitrate solution was mixed with 3 kg of dilute nitric acid to form a mixture. Then, MnO2 solid particles were added to the mixture under stirring, with the MnO2 solid particles added at a mass ratio of MnO2 / CuO of 1:0.4, and mixed thoroughly. The resulting mixture was dried overnight at 120°C, and the obtained solid was calcined in air at 350°C for 2 hours. The resulting copper-manganese cooxide catalyst is hopcalite. The catalyst surface has a very dense concentration of oxygen vacancies, thus exhibiting strong macroscopic redox activity. Furthermore, the catalyst surface exhibits a densely porous honeycomb structure, such as... Figure 1 As shown, this structure significantly expands the specific surface area of ​​the copper-manganese cooxide catalyst, increasing its effective contact area with flue gas. Furthermore, oxygen vacancies can be formed on the inner side of the pore walls, effectively increasing the density of surface oxygen vacancies. Copper is loaded onto the surface of manganese dioxide particles, which are primarily spinel-structured. The particles are spherical with an average diameter of approximately 1.8 mm. The copper loading is approximately 20 wt%, and the average diameter of the copper-loaded particles ranges from approximately 15 to 26 nm, with a specific surface area of ​​approximately 180 m². 2 / g, bulk density is approximately 0.7g / cm³ 3 .

[0033] A coil-type electrode was placed inside the discharge reactor as a high-voltage electrode, and silver paste was applied to the outside of the tube as a grounding electrode. An external AC voltage of 30 kV and a frequency of 10 kHz was applied. CO was oxidized using a low-temperature plasma discharge process. The spatial energy density during discharge was controlled at 500 J / L. In the discharge catalytic oxidation process, plasma was directly applied to the catalyst bed, then entered the catalyst bed and formed surface active oxygen functional groups. To directly enhance the in-situ oxidation of carbon monoxide, plasma was applied to a copper-manganese catalyst. All steps were carried out at room temperature and atmospheric pressure. The initial carbon monoxide concentration was approximately 10,000 ppm, and through the direct interaction between the non-thermal plasma and the catalyst, the carbon monoxide removal rate exceeded 90%.

[0034] Example 2

[0035] A steel plant uses copper-manganese cooxide as a catalyst for the synergistic plasma catalytic oxidation of carbon monoxide. The amount of copper-manganese cooxide catalyst packed inside the non-thermal plasma discharge chamber is approximately 300g, and the mass hourly space velocity of the flue gas is 30m. 3 / (h*kg). A mixed metal salt solution was prepared by adding a solution of manganese nitrate hexahydrate (Mn(NO3)2·6H2O) to a solution of copper nitrate trihydrate (Cu(NO3)2·3H2O). The concentration of the copper nitrate solution was 0.25 mol / L, and the concentration of the manganese nitrate solution was 1 mol / L. Both solutions were added in equal volumes (2 L each) to maintain a mass ratio of Mn(NO3)2 / Cu(NO3)2 of approximately 4 / 1. After stirring the mixture for 1 h, approximately 1 L of industrial ammonia water containing 25% ammonia was passed through as a precipitant, eventually forming a precipitate. The precipitate was dried in air at 110 °C for 12 h and then calcined at 400 °C for 2 h to obtain the precursor of the hopcalite catalyst. To compare the effect of different calcination temperatures on the structure of the coprecipitate, calcination temperatures were adjusted to 300, 400, 500, and 600 °C for 2 h. The catalyst sample calcined at 400 °C showed the best reactivity. However, calcination temperatures above 500℃ lead to the sintering of active microcrystals. This results in a loss of active surface area and adversely affects the performance of the obtained catalyst. Therefore, to minimize the drawbacks of the two-step calcination and pretreatment process, the calcination temperature is controlled at 400℃.

[0036] The plasma reactor was then a dielectric barrier discharge reactor, consisting of a quartz tube, a stainless steel rod (high-voltage electrode) connected to a high-voltage power supply and placed along the central axis of the quartz tube, and a stainless steel mesh (grounding electrode) outside the reactor. The high-voltage AC power supply generating the plasma used a peak voltage of 20kV and a frequency of 10kHz. The CO-containing mixed flue gas was oxidized by discharge at room temperature. Compared to the unfilled catalyst, the catalyst-filled reactor resulted in smaller voltage and current fluctuations during plasma discharge, leading to a more stable discharge process. The initial carbon monoxide concentration was approximately 1 vol%, and after plasma-catalyst synergistic oxidation, the CO concentration in the tail gas approached zero, with a conversion rate exceeding 99%.

[0037] Example 3

[0038] A carbon monoxide removal unit in a steel plant consists of a catalyst bed directly packed in the plasma zone of a dielectric barrier discharge reactor, 35m 3 / h flue gas flow rate corresponds to 1kg catalyst content. A copper-manganese cooxide catalyst was prepared using an impregnation method. The specific preparation method for the manganese dioxide particles is described in Example 1. The manganese dioxide particles, with a diameter of 5mm, were impregnated with an aqueous solution of copper nitrate trihydrate. The carrier particles and impregnation solution were dried in a furnace at 120℃ for 12h, and the resulting solid was calcined in air at 400℃ for 2h. The copper mass fraction on the particles was approximately 30wt%, and the specific surface area of ​​the catalyst particles was approximately 280m². 2 / g. The dielectric barrier discharge reactor consists of stainless steel wire and stainless steel mesh. The stainless steel wire is suspended along the axis of the tube inside and serves as a high-voltage electrode. The grounding electrode is made of stainless steel wire mesh wound around the outside of the reactor. Copper-manganese mixed oxide particles are filled into the discharge gap as a catalyst. A high-voltage power supply is applied to the internal electrodes to generate plasma. Energy is provided by an AC power supply for ionizing the reaction gas. The peak voltage is 20kV and the frequency of the AC power supply is fixed at 8.5kHz. O2 is ionized, and active oxygen particles O( 1 D). Reactive oxygen can react to generate ozone or other oxygen-containing functional groups and act on the catalyst bed. After oxidation by the active groups generated by discharge, the CO content in the flue gas is reduced from over 8000 ppm to 400 ppm, with a conversion rate of over 95%.

[0039] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the inventive concept should also be considered within the scope of protection of the present invention.

Claims

1. A method for removing carbon monoxide from flue gas by plasma discharge coupled catalytic oxidation, characterized in that: A copper-manganese cooxide catalyst with oxygen vacancies on its surface is filled into the discharge chamber of a plasma reactor, and then flue gas is introduced into the discharge chamber for discharge catalytic oxidation to remove carbon monoxide components from the flue gas. The copper-manganese cooxide catalyst is prepared by the following method: a solution containing manganese ions and copper ions is subjected to coprecipitation to obtain a copper-manganese coprecipitate, which is then dried, calcined in air, and crushed to obtain the final product. or, The copper-manganese cooxide catalyst is prepared by the following method: manganese salt is calcined to obtain manganese oxide, the manganese oxide is soaked in an acid solution containing copper ions, the mixture is dried, the resulting solid is calcined in air and then crushed to obtain the catalyst. The molar ratio of Mn / Cu in the copper-manganese cooxide catalyst is 2.5:1 to 4:1; The roasting conditions are: temperature 300~450℃, time 1~2h.

2. The method for removing carbon monoxide from flue gas by plasma discharge coupled catalytic oxidation according to claim 1, characterized in that: The acid concentration in the copper-containing acid solution is 3~7 mol / L.

3. A method for removing carbon monoxide from flue gas by plasma discharge coupled catalytic oxidation according to any one of claims 1 to 2, characterized in that: The specific surface area of the copper-manganese co-oxide catalyst is 180-240 m 2 / g, and the bulk density is 0.65-0.75 g / cm 3 .

4. The method for removing carbon monoxide from flue gas by plasma discharge coupled catalytic oxidation according to claim 1, characterized in that: The filling amount of the copper-manganese co-oxide catalyst in the discharge cavity is proportional to the flow of the flue gas; the mass space velocity of the flue gas is 25-35 m 3 / (h*kg).

5. The method for removing carbon monoxide from flue gas by plasma discharge coupled catalytic oxidation according to claim 1, characterized in that: The carbon monoxide concentration in the flue gas is 8000~10000 ppm.

6. The method for removing carbon monoxide from flue gas by plasma discharge coupled catalytic oxidation according to claim 1, characterized in that: The discharge conditions are: voltage of 10~30kV and discharge frequency of 1~10kHz.

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