Composite carrier type carbon monoxide catalyst, preparation method thereof and flue gas purification system

Abstract

The invention relates to a composite carrier type carbon monoxide catalyst, a preparation method thereof and a flue gas purification system.The catalyst takes Co3O4 as a catalytic main body, a formed Mo-O-Sn bond can initiate strong electron interaction, the adsorption degree of SO2 at active sites is weakened, and sulfate generation is inhibited from the source; the preparation method comprises the following steps: dissolving a cobalt source, a molybdenum source and a tin source in an ethanol solution by adopting a complexing agent-assisted ultrasonic coprecipitation method, and controlling the ratio of carboxyl in the complexing agent to cobalt ions, molybdenum ions and tin ions to prepare a catalyst precursor; and carrying out stepped heat treatment on the precursor to obtain the mesoporous metal oxide catalyst, the catalyst can realize complete conversion of CO under the conditions that the temperature is 120 DEG C and the air speed is 30000h <-1 >; the catalyst continuously operates for 21h in a harsh working condition containing 240ppm of SO2 and 13% of H2O, and the activity retention rate is greater than 89%.

Description

Technical Field

[0001] This application relates to the field of catalyst technology for air pollution control, and more particularly to a composite supported carbon monoxide catalyst and its preparation method, as well as a flue gas purification system. Background Technology

[0002] Carbon monoxide (CO), a major air pollutant, not only participates in the formation of photochemical smog, becoming an important precursor to haze, but also, due to its strong binding affinity to hemoglobin, easily causes asphyxiation in humans, significantly impacting the nervous and cardiovascular systems. In the steel production process, industrial exhaust gases from sintering and pelletizing processes contain large amounts of CO, typically at concentrations of 8000 mg / m³. 3 ~10000mg / m 3 .

[0003] Currently, CO treatment technologies mainly include catalytic oxidation, cryogenic separation, Cosorb, adsorption, and membrane separation. Catalytic oxidation has attracted significant attention due to its high activity and low pollution. The core of catalytic oxidation is the catalyst. Currently used catalysts are mainly divided into two categories: noble metal catalysts and transition metal oxide catalysts. Traditional noble metal catalysts (such as Pd / Al2O3) exhibit excellent low-temperature activity, but suffer from sensitivity to sulfides, easy poisoning, and high cost. Existing non-noble metal catalysts, while inexpensive, still have problems such as high ignition temperature, low activity, and poor sulfur and water resistance. For example, the disclosed CeO2-Co3O4 system exhibits significant defects under sulfur- and water-containing conditions: high ignition temperature (T... 90 The activity decays by more than 30% within 6 hours due to sulfation (>180℃). In addition, existing technologies show that MoO3, when used as a catalyst promoter, requires activation at temperatures above 500℃ to form an active phase, making it difficult to adapt to low-temperature flue gas conditions.

[0004] In view of this, it is necessary to design a composite supported carbon monoxide catalyst and its preparation method, as well as a flue gas purification system, to solve the above problems. Summary of the Invention

[0005] This application provides a composite supported carbon monoxide catalyst and its preparation method, as well as a flue gas purification system, to solve the problem that there is currently no non-precious metal catalyst that combines low-temperature activity with sulfur and water resistance. In a first aspect, this application provides a composite supported carbon monoxide catalyst, the composition of which includes a MoO3-SnO2-Co3O4 composite.

[0006] In some embodiments, the content of Co3O4 in the MoO3-SnO2-Co3O4 composite is 73.81% to 93% by mass, the content of SnO2 is 8% to 25.06%, and the content of MoO3 is 0.3% to 1.64%.

[0007] Secondly, this application provides a method for preparing the above-mentioned composite supported carbon monoxide catalyst, comprising the following steps: A cobalt source, a molybdenum source, and a tin source are provided. The cobalt source, the molybdenum source, and the tin source are dissolved in an ethanol-water solution to obtain a precursor solution. A complexing agent is added to the precursor solution to obtain a precursor chelate complex solution. Under ultrasonic treatment conditions, a precipitant is added to the precursor chelate complex solution to obtain an ultrasonic coprecipitate; the ultrasonic coprecipitate is then aged to obtain a catalyst precursor. The catalyst precursor was subjected to vacuum drying, pre-oxidation, and calcination in sequence to obtain the composite supported carbon monoxide catalyst.

[0008] In some embodiments, the molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is (93~94.5):(0.3~1.1):(5.5~17.5).

[0009] In some embodiments, in the step of adding a precipitant to the precursor chelate complex solution under ultrasonic treatment, the precipitant is added dropwise until the pH of the precursor chelate complex solution containing the precipitant is 8-11.

[0010] In some embodiments, the vacuum drying process includes drying the catalyst precursor for 4 to 12 hours at a temperature of 100°C to 150°C and a pressure of -0.1 MPa to -0.02 MPa.

[0011] In some embodiments, the pre-oxidation treatment includes: heating the vacuum-dried catalyst precursor to 300°C~400°C, holding it at 300°C~400°C for 1h~4h, and then cooling it to 0°C~40°C; the heating rate during the pre-oxidation treatment is 2°C / min~10°C / min; and / or, The calcination process includes: heating the pre-oxidized catalyst precursor to 400℃~650℃, holding it at 400℃~650℃ for 3h~6h, and then cooling it to 0℃~40℃; the heating rate during the calcination process is 2℃ / min~10℃ / min.

[0012] In some embodiments, the cobalt source includes any one or more of cobalt nitrate, cobalt acetate, cobalt chloride, and cobalt sulfate; and / or, The molybdenum source includes any one or more of ammonium molybdate, potassium molybdate, molybdenum nitrate, and molybdenum acetate; and / or, The tin source includes any one or more of stannous chloride, stannous tetrachloride, stannous nitrate, and stannous sulfate; and / or, In the ethanol-water solution, the mass percentage of ethanol is 50% to 75%; and / or, The mass ratio of the cobalt source to the ethanol-water solution is (1.5:1) to (2:1); and / or, The complexing agent includes any one or more of citric acid, acetic acid, oxalic acid, tartaric acid, and gluconic acid; and / or, The ratio of the molar mass of the carboxyl group in the complexing agent to the total molar mass of cobalt ions, molybdenum ions and tin ions in the precursor solution is (1:1) to (1:2).

[0013] In some embodiments, the precipitant includes any one or more of sodium carbonate solution, sodium bicarbonate solution, ammonia, sodium hydroxide solution, and potassium hydroxide solution; and / or, The frequency of the ultrasonic treatment is 20kHz to 60kHz, and the power of the ultrasonic treatment is 100W to 400W; and / or, The aging process takes 6 to 48 hours.

[0014] Thirdly, this application provides a flue gas purification system, wherein the system is loaded with the composite carrier-type carbon monoxide catalyst as described above, and the system is equipped with an air velocity control module; The reaction space velocity in the airspeed control module is 25,000 h. -1 ~35000h -1 ; The system is suitable for processing flue gas from steel sintering pellets with a temperature of 100℃~180℃, a sulfur content of ≤500ppm, and a moisture content of ≤15%.

[0015] The technical solutions provided in this application have the following advantages compared with the prior art: 1. The composite supported carbon monoxide catalyst provided in this application comprises a MoO3-SnO2-Co3O4 composite, wherein the content of Co3O4 in the MoO3-SnO2-Co3O4 composite is 73.81%~93%, the content of SnO2 is 8%~25.06%, and the content of MoO3 is 0.3%~1.64%; this catalyst uses Co3O4 as the catalyst host, and the Co in its spinel structure 3+ / Co2+ Redox pairs are the main active sites in the CO oxidation reaction; however, when used alone, these active sites are easily deactivated by SO2 poisoning and the formation of cobalt sulfate. Therefore, the introduction of SnO2 not only enhances the density of acidic sites on the support surface and promotes O2 activation, but more importantly, it constructs a "high-speed electron channel" due to its high electron mobility. The key role of trace amounts of MoO3 is reflected in the dynamic oxygen regulation: during the reaction, Mo... 6+ Reversible conversion to Mo 5+ This effectively accelerates the cycling efficiency of lattice oxygen. At the same time, the Mo-O-Sn bond formed at the interface between MoO3 and SnO2 triggers strong electronic interactions and significantly weakens the adsorption strength of SO2 at the active sites, thus inhibiting sulfate formation at the source.

[0016] 2. The method for preparing composite supported carbon monoxide provided in this application involves using a complexing agent-assisted ultrasonic co-precipitation method. Cobalt, molybdenum, and tin sources are dissolved in an ethanol-water solution, and the ratio of carboxyl groups in the complexing agent to the total content of cobalt, molybdenum, and tin ions in the precursor solution is precisely controlled to obtain a catalyst precursor. Finally, the catalyst precursor is subjected to a stepwise heat treatment to obtain a mesoporous metal oxide catalyst. This preparation method is simple, low-cost, energy-efficient, and does not emit harmful gases, making it environmentally friendly. It has a wide applicable temperature range and exhibits good resistance to water and carbon dioxide toxicity. The prepared catalyst can withstand temperatures as low as 120°C and a space velocity of 30,000 h⁻¹. -1 It can achieve complete CO conversion under certain conditions; it can operate continuously for 21 hours with an activity retention rate of >89% in harsh conditions containing 240ppm SO2 and 13% H2O, and is suitable for the purification of low-temperature and high-sulfur environments such as steel sintering flue gas. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This shows a schematic diagram of XRD analysis in a composite supported carbon monoxide catalyst provided in Example 1 of this application; Figure 2 The diagram shows a comparison of in-situ infrared spectral analysis of the sulfur resistance performance of a composite supported carbon monoxide catalyst provided in Example 1 of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] Various embodiments of this application may exist in the form of a range. It should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of this application. Therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated in this application, it means including any referenced number (fraction or integer) within the indicated range. Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this application can be purchased commercially or prepared by existing methods. In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. In addition, in this application, the terms "comprising," "including," etc., mean "including but not limited to." In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any actual relationship or order between these entities or operations. In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or multiple.

[0022] This application provides a composite supported carbon monoxide catalyst, the composition of which includes a MoO3-SnO2-Co3O4 complex.

[0023] As an optional implementation, in the embodiments of this application, the content of Co3O4 in the MoO3-SnO2-Co3O4 composite is 73.81%~93% by mass percentage, the content of SnO2 is 8%~25.06%, and the content of MoO3 is 0.3%~1.64%.

[0024] However, if the Co3O4 content is below 73.81%, it will lead to insufficient number of active sites and a decrease in the overall structural strength of the catalyst; if the Co3O4 content is above 93%, it will lead to agglomeration and sintering of active phase crystals, weakening the support effect; if the SnO2 content is below 8%, it will lead to insufficient SnO2 dispersion ability and a decrease in the overall structural stability of the catalyst; if the SnO2 content is above 25.06%, it will lead to the active sites being covered and the pores being blocked; if the MoO3 content is below 0.3%, it will lead to ineffective electronic additives and insufficient anti-poisoning performance; if the MoO3 content is above 1.64%, it will lead to the formation of a low-melting-point molybdate phase, blocking the pores and covering strong sites.

[0025] It is understandable that, with Co3O4 as the catalyst host, the Co in its spinel structure... 3+ / Co 2+ Redox pairs are the main active sites in the CO oxidation reaction; however, when used alone, these active sites are easily deactivated by SO2 poisoning and the formation of cobalt sulfate. Therefore, the introduction of SnO2 not only enhances the acidic site density on the surface of the Co3O4 support and promotes O2 activation, but more importantly, it constructs a "high-speed electron channel" due to its high electron mobility.

[0026] The key role of trace amounts of MoO3 lies in the dynamic oxygen regulation: during the reaction process, Mo... 6+ Reversible conversion to Mo 5+ This effectively accelerates the cycling efficiency of lattice oxygen.

[0027] At the same time, the Mo-O-Sn bond formed at the interface between MoO3 and SnO2 will trigger strong electronic interactions and significantly weaken the adsorption strength of SO2 at the active site, thus inhibiting sulfate formation from the source.

[0028] It is evident that the functional division of labor among the aforementioned components becomes the core of coordinating electronic structure regulation.

[0029] Based on a general inventive concept, this application provides a method for preparing the above-mentioned composite supported carbon monoxide catalyst, comprising the following steps: Step S1: Provide a cobalt source, a molybdenum source, and a tin source. Dissolve the cobalt source, the molybdenum source, and the tin source in an ethanol-water solution to obtain a precursor solution. Add a complexing agent to the precursor solution to obtain a precursor chelate complex solution. Through liquid-phase mixing and molecular-level chelation, achieve highly uniform premixing of the three metal elements cobalt (Co), tin (Sn), and molybdenum (Mo) at the atomic scale, laying the foundation for the subsequent formation of an active phase with uniform composition, high dispersion, and specific microstructure. Step S2: Under ultrasonic treatment, a precipitant is added to the precursor chelate complex solution to obtain an ultrasonic coprecipitate; the ultrasonic coprecipitate is aged to obtain a catalyst precursor; the ultrasonic cavitation effect is used to achieve instantaneous and uniform nucleation and grain growth control in the precipitation process, and the crystal structure and physicochemical properties of the precipitate are further optimized by aging treatment, thereby obtaining a catalyst precursor with highly uniform composition, fine particles and narrow particle size distribution; Step S3: The catalyst precursor is subjected to vacuum drying, pre-oxidation, and calcination treatment in sequence to obtain the composite supported carbon monoxide catalyst. Through a staged heat treatment process, the removal of organic matter in the precursor, the crystallization of the amorphous phase, and the formation and growth of the target active crystalline phase are precisely controlled, and a composite metal oxide catalyst with high specific surface area, suitable pore structure, good crystallinity, and stable chemical state is finally constructed.

[0030] The method for preparing the composite supported carbon monoxide catalyst provided in this application involves using a complexing agent-assisted ultrasonic co-precipitation method to dissolve cobalt, molybdenum, and tin sources in an ethanol-water solution. The ratio of carboxyl groups in the complexing agent to the total content of cobalt, molybdenum, and tin ions in the precursor solution is precisely controlled to obtain a catalyst precursor. Finally, the catalyst precursor is subjected to a stepwise heat treatment to obtain a mesoporous metal oxide catalyst. This preparation method is simple, low-cost, energy-efficient, and does not emit harmful gases, making it environmentally friendly. It has a wide applicable temperature range and exhibits excellent resistance to water and carbon dioxide toxicity.

[0031] The catalyst prepared was subjected to low temperature of 120℃ and space velocity of 30,000 h⁻¹. -1 It can achieve complete CO conversion under certain conditions; it can operate continuously for 21 hours in harsh conditions containing 240ppm SO2 and 13% H2O, with an activity retention rate of >89% (30% higher than the traditional CeO2-Co3O4 system), and is suitable for the purification of low-temperature and high-sulfur environments such as steel sintering flue gas.

[0032] As an optional implementation, in this embodiment of the application, the molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is (93.5~94.5):(0.3~1.1):(5.5~17.5).

[0033] As an optional implementation, in this embodiment of the application, in the step of adding a precipitant to the precursor chelate complex solution under ultrasonic treatment, the precipitant is added until the pH of the precursor chelate complex solution containing the precipitant is 8-11; preferably, the precipitant is added until the pH of the precursor chelate complex solution containing the precipitant is 10.

[0034] Therefore, setting the pH of the precursor chelate complex solution to 8-11 ensures that cobalt (Co), tin (Sn), and molybdenum (Mo) metal ions in the solution can be simultaneously and completely precipitated as hydroxides or basic salts, thereby achieving highly uniform co-precipitation of multiple metal components at the atomic scale and avoiding component segregation caused by pH differences in precipitation of different metal ions.

[0035] As an optional implementation, in this embodiment of the application, the vacuum drying process includes drying the catalyst precursor for 4h to 12h at a temperature of 100℃ to 150℃ and a pressure of -0.1MPa to -0.02MPa; preferably, the vacuum drying process is drying the catalyst precursor for 6h at a temperature of 120℃ and a pressure of -0.05MPa.

[0036] This approach aims to maximize the protection of the catalyst precursor's microstructure while ensuring drying efficiency, preventing Ostwald ripening or agglomeration of nano-active components during drying. This results in a finished catalyst with high specific surface area, high porosity, and highly dispersed active sites. Vacuum drying, in particular, significantly lowers the boiling point of water, causing it to vaporize violently at temperatures well below 100°C, greatly weakening the capillary force caused by the surface tension of liquid water. However, the vacuum level cannot be lower than -0.1 MPa during drying. Excessive vacuum (extremely low absolute pressure) would cause water to vaporize rapidly and instantly, like a "boiling over." This violent phase transition would generate enormous internal stress, sufficient to destroy the already formed fine nanostructure or mesoporous / macroporous framework, leading to a decrease in catalyst mechanical strength or even pulverization, thus reducing the overall performance of the catalyst.

[0037] As an optional implementation, in this embodiment, the pre-oxidation treatment includes: heating the vacuum-dried catalyst precursor to 300°C~400°C, holding it at 300°C~400°C for 1h~4h, and then cooling it to 0°C~40°C; the heating rate during the pre-oxidation treatment is 2°C / min~10°C / min. Preferably, the pre-oxidation treatment is: heating the vacuum-dried catalyst precursor to 350°C at a heating rate of 2°C / min, holding it at 350°C for 3h, and then cooling it to 20°C.

[0038] The pre-oxidation stage is to carbonize the complexing agent to form a mesoporous template; however, the heating temperature during pre-oxidation should not exceed 400℃, otherwise it will lead to template failure and pore structure collapse, as well as sintering and deactivation of active components. Pre-oxidation can effectively decompose citric acid to produce a pore-forming template; therefore, it is indispensable for mesoporous construction.

[0039] As an optional implementation, in this embodiment of the application, the calcination treatment includes: heating the pre-oxidized catalyst precursor to 400℃~650℃, holding it at 400℃~650℃ for 3h~6h, and then cooling it to 0℃~40℃; the heating rate during the calcination treatment is 2℃ / min~10℃ / min. Preferably, the calcination treatment is: heating the pre-oxidized catalyst precursor to 550℃ at a heating rate of 5℃ / min, holding it at 550℃ for 4h, and then cooling it to 20℃.

[0040] The calcination stage is to complete the transformation of the Co3O4 spinel phase; however, the heating temperature during calcination must not exceed 400℃, otherwise it will cause significant sintering and growth of the Co3O4 nanocrystals. The sharp increase in grain size will directly lead to a significant decrease in the specific surface area of ​​the catalyst and a sharp reduction in the number of active sites. At the same time, the Co3O4 spinel phase will undergo irreversible thermal decomposition to generate CoO. The CO catalytic activity of CoO is much lower than that of Co3O4, and this process will lead to catalyst structural reorganization and densification, resulting in permanent deactivation. In addition, excessively high calcination temperatures will intensify the strong interaction between the active component (Co3O4) and the support (such as Al2O3, TiO2, etc.), which may lead to the formation of inert compounds such as inactive cobalt aluminum spinel (CoAl2O4) that coat the active sites. At the same time, it will also destroy the mesoporous structure carefully formed in the pre-oxidation stage, leading to pore collapse.

[0041] As an optional implementation, in this embodiment of the application, the cobalt source includes any one or more of cobalt nitrate, cobalt acetate, cobalt chloride, and cobalt sulfate; preferably, the cobalt source is cobalt nitrate. The molybdenum source includes any one or more of ammonium molybdate, potassium molybdate, molybdenum nitrate, and molybdenum acetate; preferably, the molybdenum source is ammonium molybdate. The tin source includes any one or more of stannous chloride, stannous tetrachloride, stannous nitrate, and stannous sulfate; preferably, the tin source is stannous chloride. In the ethanol-water solution, the mass percentage of (anhydrous) ethanol is 50% to 75%. The mass ratio of the cobalt source to the ethanol-water solution is (1.5:1) to (2:1); The complexing agent includes any one or more of citric acid, acetic acid, oxalic acid, tartaric acid, and gluconic acid; preferably, the complexing agent is citric acid. The ratio of the molar mass of the carboxyl group in the complexing agent to the total molar mass of cobalt ions, molybdenum ions and tin ions in the precursor solution is (1:1) to (1:2); preferably, the ratio of the molar mass of the carboxyl group in the complexing agent to the total molar mass of cobalt ions, molybdenum ions and tin ions in the precursor solution is 1:1.2.

[0042] As an optional implementation, in this embodiment of the application, the precipitant includes any one or more of sodium carbonate solution, sodium bicarbonate solution, ammonia water, sodium hydroxide solution, and potassium hydroxide solution; preferably, the precipitant is sodium carbonate solution; The frequency of the ultrasonic treatment is 20kHz to 60kHz, and the power of the ultrasonic treatment is 100W to 400W; preferably, the frequency of the ultrasonic treatment is 40kHz, and the power of the ultrasonic treatment is 200W. The aging process takes 6 to 48 hours; preferably, it takes 24 hours.

[0043] Based on a general inventive concept, embodiments of this application provide a flue gas purification system, wherein the system is loaded with the composite carrier-type carbon monoxide catalyst as described above, and the system is equipped with an airspeed control module. The reaction space velocity in the airspeed control module is 25,000 h. -1 ~35000h -1 ; The system is suitable for processing flue gas from steel sintering pellets with a temperature of 100℃~180℃, a sulfur content of ≤500ppm, and a moisture content of ≤15%.

[0044] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0045] Example 1 Example 1 provides a method for preparing a composite supported carbon monoxide catalyst, comprising the following steps: Step S1: Provide cobalt nitrate hexahydrate, ammonium molybdate tetrahydrate, and stannous chloride dihydrate. 92.8 g of cobalt nitrate hexahydrate, 0.6 g of ammonium molybdate tetrahydrate, and 13.2 g of stannous chloride dihydrate were dissolved in 200 mL of an ethanol-water solution (the volume ratio of anhydrous ethanol to water was 3:1) to obtain a precursor solution; 24 g of citric acid was added to the precursor solution to ensure the formation of a stable complexing system, thus obtaining a precursor chelate complex solution. The molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is 94:1:17. The ratio of the molar mass of the carboxyl group in the citric acid to the total molar mass of cobalt ions, molybdenum ions, and tin ions in the precursor solution is 1.2:1. Step S2: Under ultrasonic treatment, sodium carbonate solution is added to the precursor chelate complex solution to obtain an ultrasonic coprecipitate; the ultrasonic coprecipitate is aged to obtain a catalyst precursor. In the step of adding a precipitant to the precursor chelate complex solution under ultrasonic treatment, sodium carbonate solution is added dropwise until the pH of the precursor chelate complex solution containing the sodium carbonate solution is 10 ± 0.2. The ultrasonic treatment frequency is 40kHz, the ultrasonic treatment power is 200W, and the aging treatment time is 24h. Step S3: The catalyst precursor is subjected to vacuum drying, pre-oxidation and calcination in sequence to obtain the composite supported carbon monoxide catalyst.

[0046] The vacuum drying process is as follows: the catalyst precursor is dried for 6 hours at a temperature of 120°C and a pressure of -0.05 MPa. The pre-oxidation treatment includes: heating the vacuum-dried catalyst precursor to 350°C at a heating rate of 2°C / min, holding it at 350°C for 3 hours, and then cooling it to room temperature. The calcination process is as follows: the pre-oxidized catalyst precursor is heated to 550°C at a heating rate of 5°C / min, held at 550°C for 4 hours, and then cooled to room temperature.

[0047] The catalyst prepared above comprises a MoO3-SnO2-Co3O4 composite; in the MoO3-SnO2-Co3O4 composite, the content of Co3O4 is 84.61% by mass percentage, the content of SnO2 is 14.58%, and the content of MoO3 is 0.81%.

[0048] The catalyst prepared in Example 1 was analyzed by X-ray diffraction spectra (XRD), and the results are as follows: Figure 1 As shown, obvious diffraction peaks of Co3O4 can be seen, indicating good crystallinity; no obvious SnO2 and MoO3 peaks were found, indicating that SnO2 and MoO3 are highly dispersed on the surface of Co3O4.

[0049] Analysis using the nitrogen adsorption-desorption isotherm (BET) revealed that the catalyst prepared in Example 1 had a specific surface area of ​​165 m². 2 / g, and the desorption curve data were processed and analyzed using the Barrett-Joyner-Halenda (BJH) model, and it was found that the mesoporous content of the catalyst in the 5nm~15nm range was 75%.

[0050] This embodiment also provides a flue gas purification system, which is loaded with the aforementioned catalyst and is equipped with a space velocity control module; the reaction space velocity in the space velocity control module is 30,000 h⁻¹. -1 ; The flue gas purification system under the above conditions was used to treat simulated flue gas with a temperature of 120℃ and a volume of 240ppm SO2 and 13% H2O. The results showed that the catalyst achieved a 100% conversion rate for the initial CO and maintained 95.2% activity after 21 hours of continuous operation.

[0051] Example 2 Example 2 provides a method for preparing a composite supported carbon monoxide catalyst. The difference between Example 1 and Example 2 is that the content of cobalt ions in the cobalt source is different in step S1.

[0052] In step S1 of Example 2, the molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is 93:1:17.

[0053] The remaining steps are the same as in Example 1, and will not be repeated here.

[0054] The catalyst prepared above comprises a complex of MoO3-SnO2-Co3O4; In the MoO3-SnO2-Co3O4 composite prepared in Example 2, the content of Co3O4 was 75.13% by mass percentage, the content of SnO2 was 23.46% and the content of MoO3 was 1.41%.

[0055] Analysis using the nitrogen adsorption-desorption isotherm (BET) revealed that the catalyst prepared in Example 2 had a specific surface area of ​​160 m². 2 / g.

[0056] Example 2 also provides a flue gas purification system, which differs from Example 1 in that the catalyst loaded is different. The catalyst loaded in the flue gas purification system of Example 2 corresponds to the catalyst prepared in Example 2.

[0057] The remaining steps are the same as in Example 1, and will not be repeated here.

[0058] The flue gas purification system provided in Example 2 was used to treat simulated flue gas, which was the same as that in Example 1.

[0059] The results showed that the catalyst in Example 2 achieved a conversion rate of 99% for the initial CO, and after 21 hours of continuous operation, the catalyst maintained 95.7% of its activity.

[0060] Comparative Examples 1-2 Comparative Examples 1 and 2 respectively provide a method for preparing a composite supported carbon monoxide catalyst. The difference between them and Example 1 is that the content of cobalt ions in the cobalt source is different in step S1.

[0061] In step S1 of Comparative Example 1, the molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is 90:1:17.

[0062] In step S1 of Comparative Example 2, the molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is 97:1:17.

[0063] The remaining steps are the same as in Example 1, and will not be repeated here.

[0064] The catalyst prepared above comprises a complex of MoO3-SnO2-Co3O4; In the MoO3-SnO2-Co3O4 composite prepared in Comparative Example 1, the content of Co3O4 was 74.26% by mass percentage, the content of SnO2 was 24.31% and the content of MoO3 was 1.43%. In the MoO3-SnO2-Co3O4 composite prepared in Comparative Example 2, the content of Co3O4 was 76.78% by mass percentage, the content of SnO2 was 1.38%, and the content of MoO3 was 21.94%.

[0065] Analysis using the nitrogen adsorption-desorption isotherm (BET) revealed that the catalyst prepared in Comparative Example 1 had a specific surface area of ​​142 m². 2 / g; The specific surface area of ​​the catalyst prepared in Comparative Example 2 was 159 m² / g. 2 / g.

[0066] Comparative Examples 1 and 2 also provide a flue gas purification system, which differs from Example 1 in that the catalyst loaded is different. The catalyst loaded in the flue gas purification systems of Comparative Examples 1 and 2 corresponds to the catalyst prepared in Comparative Examples 1 and 2, respectively.

[0067] The remaining steps are the same as in Example 1, and will not be repeated here.

[0068] The flue gas purification systems provided in Comparative Examples 1 and 2 were used to treat simulated flue gas, which was the same as that in Example 1.

[0069] The results showed that the catalyst in Comparative Example 1 achieved a conversion rate of 90% for the initial CO, and after 21 hours of continuous operation, the catalyst maintained 76% of its activity.

[0070] The catalyst in Comparative Example 2 achieved a conversion rate of 92% for the initial CO and maintained 63% activity after 21 hours of continuous operation.

[0071] Comparative Examples 1-2 and 1-2 show that the change in cobalt content has little effect on the specific surface area of ​​the prepared catalyst. However, after application, the catalyst with cobalt content within the scope of this application still has high activity.

[0072] Example 3 Example 3 provides a method for preparing a composite supported carbon monoxide catalyst. The difference from Example 1 is that the content of molybdenum ions in the molybdenum source is different in step S1.

[0073] In step S1 of Example 3, the molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is 94:0.8:17.

[0074] The remaining steps are the same as in Example 1, and will not be repeated here.

[0075] The catalyst prepared above comprises a MoO3-SnO2-Co3O4 composite; in the MoO3-SnO2-Co3O4 composite, the content of Co3O4 is 73.81% by mass percentage, the content of SnO2 is 25.06%, and the content of MoO3 is 1.13%.

[0076] Example 3 also provides a flue gas purification system, which differs from Example 1 in that the catalyst loaded is different. The catalyst loaded in the flue gas purification system in Example 3 corresponds to the catalyst prepared in Example 3.

[0077] The remaining steps are the same as in Example 1, and will not be repeated here.

[0078] The flue gas purification system provided in Example 3 was used to treat simulated flue gas, which was the same as that in Example 1.

[0079] The results showed that the catalyst in Example 3 achieved a conversion rate of 99.2% for the initial CO, and after 21 hours of continuous operation, the catalyst maintained an activity of 94.3%.

[0080] Comparative Examples 3-4 Comparative Examples 3 and 4 respectively provide a method for preparing a composite supported carbon monoxide catalyst. The difference between them and Example 1 is that the content of molybdenum ions in the molybdenum source is different in step S1.

[0081] In step S1 of Comparative Example 3, the molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is 94:0:17.

[0082] In step S1 of Comparative Example 4, the molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is 94:1.5:17.

[0083] The remaining steps are the same as in Example 1, and will not be repeated here.

[0084] The catalyst prepared above comprises a complex of MoO3-SnO2-Co3O4; In the MoO3-SnO2-Co3O4 composite prepared in Comparative Example 3, the content of Co3O4 was 76.38% by mass percentage, the content of SnO2 was 23.62% and the content of MoO3 was 0%.

[0085] In the MoO3-SnO2-Co3O4 composite prepared in Comparative Example 4, the content of Co3O4 was 73.89% by mass percentage, the content of SnO2 was 24% and the content of MoO3 was 2.11%.

[0086] Analysis using the nitrogen adsorption-desorption isotherm (BET) revealed that the catalyst prepared in Comparative Example 3 had a specific surface area of ​​154 m². 2 / g; the specific surface area of ​​the catalyst prepared in Comparative Example 4 was 156 m² / g. 2 / g.

[0087] In addition, the antisulfur performance of the catalyst prepared in Example 1 (Co:Mo:Sn = 94:1:17) was evaluated. The catalyst was placed in SO2-free flue gas and subjected to in-situ infrared spectroscopy analysis. The results are as follows: Figure 2 As shown in (a); in addition, the same catalyst was placed in a flue gas containing SO2 and in-situ infrared spectroscopy analysis was performed, and the results are as follows. Figure 2 As shown in (b). As can be seen, the catalyst of Example 1, after undergoing sulfur resistance testing, Figure 2 (a) shows that after CO + O2 + H2O is introduced at the test temperature, the composite catalyst at 1244 cm⁻¹... -1 and 1445cm -1 The peak appearing at 1338 cm⁻¹ can be attributed to monodentate carbonate, while the peak at 1338 cm⁻¹ belongs to monodentate carbonate. -1 and 1558cm -1 The peak appearing at 2100–2200 cm⁻¹ can be attributed to the carboxylate vibrational mode. -1 The bimodal pattern observed within the range can be attributed to gaseous CO, while the peak at 2300–2400 cm⁻¹ can be attributed to gaseous CO. -1 The double peaks observed within the catalyst can be attributed to gaseous CO2, indicating that CO is converted to CO2 under the action of the catalyst, and CO2 forms carbonates on the catalyst surface. As time progresses, the intensity of the carbonate peak on the catalyst surface decreases, while the peak intensity at 1620 cm⁻¹ decreases. -1 A new peak appeared, which can be attributed to adsorbed H2O, and the intensity of the peak gradually increased.

[0088] Figure 2 (b) Introduce 50 ppm SO2 at 800~1050 cm⁻¹ -1 The intensity of the bicarbonate peak within the range increases significantly with time, and reaches 1180 cm⁻¹. -1 A sulfate peak was observed at 1359 cm⁻¹, and its intensity increased with time, indicating the accumulation of sulfate and bicarbonate on the catalyst surface. Furthermore, a peak of sulfate was observed at 1359 cm⁻¹. -1 and 1510cm -1 SO2 and SO3 adsorption were detected at 2067 cm⁻¹, respectively. With increasing time, the adsorption of SO2 and SO3 at 2067 cm⁻¹ increased. -1CO adsorption on SnO2 was observed, indicating that some SnO2 was reduced to SnO in the catalyst. It can be inferred that the presence of MnO3-SnO2-Co3O4 in the composite catalyst allows H2O to dissociate into OH and H groups on the catalyst surface. The OH groups can participate in the CO oxidation reaction, thereby improving the CO oxidation activity. The accumulation of carbonates and sulfates on the catalyst surface will affect the catalyst activity.

[0089] In addition, a sulfur resistance experiment was also conducted on the catalyst of Comparative Example 3. In-situ infrared spectroscopy analysis of the catalyst after the sulfur resistance experiment showed that, after being treated with the same sulfide adsorption as in Example 1, the SO₂ concentration of Comparative Example 3 was significantly reduced. 2- The characteristic peak intensity is extremely high, at 1180 cm⁻¹. - ¹(The results of the in-situ infrared spectroscopy analysis of Comparative Example 3 can be obtained experimentally and are therefore not provided here). However, after conducting the sulfur resistance experiment, the intensity of the corresponding peak using the catalyst of Example 1 of this invention decreased by 63%, indicating that the catalyst prepared in Example 1 can deposit a large amount of sulfate, thus exhibiting excellent sulfur resistance.

[0090] Comparative Examples 3 and 4 also provide a flue gas purification system, which differs from Example 1 in that the catalyst loaded is different. The catalyst loaded in the flue gas purification systems of Comparative Examples 3 and 4 are respectively the catalysts prepared in Comparative Examples 3 and 4.

[0091] The remaining steps are the same as in Example 1, and will not be repeated here.

[0092] The flue gas purification systems provided in Comparative Examples 3 and 4 were used to treat simulated flue gas, which was the same as that in Example 1.

[0093] The results showed that the catalyst in Comparative Example 3 achieved a conversion rate of 97% for the initial CO, and after 21 hours of continuous operation, the catalyst maintained 46% of its activity.

[0094] The catalyst in Comparative Example 4 achieved a conversion rate of 94.3% for the initial CO, and after 21 hours of continuous operation, the catalyst maintained 86% of its activity.

[0095] Analysis of the catalysts in Examples 1, 3, and Comparative Examples 3-4 revealed that when the MoO3 content in the catalyst exceeded 1%, molybdenum enrichment occurred on the catalyst surface. When the molybdenum content in the catalyst precursor was excessive, during calcination at 550°C, molybdenum species (mainly in the form of MoO3) achieved high mobility due to the high temperature, migrating and agglomerating into large particles on the catalyst surface. This process produces two destructive effects: physical blockage and structural damage: the migrating MoO3 particles block the mesoporous template formed by the carbonization of the complexing agent, directly damaging the integrity of the pores during aggregation; and promoting overall sintering: as a low-temperature eutectic component, MoO3 significantly accelerates the sintering rate of Co3O4 and SnO2 nanoparticles, leading to particle coarsening. These "migration and aggregation" effects collectively cause the structural collapse of the catalyst framework, manifested as a sharp decrease in specific surface area (see Comparative Example 4, where the BET specific surface area is only 50 m²). 2 The MoO3 content (g) and porosity decrease significantly, leading to a sharp decline in catalytic activity. Therefore, the MoO3 content in the catalyst must be strictly controlled between 0.3% and 1%.

[0096] Example 4 Example 4 provides a method for preparing a composite supported carbon monoxide catalyst. The difference from Example 1 is that the content of tin ions in the tin source is different in step S1.

[0097] In step S1 of Example 4, the molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is 94:1:5.5.

[0098] The remaining steps are the same as in Example 1, and will not be repeated here.

[0099] The catalyst prepared above comprises a complex of MoO3-SnO2-Co3O4; In the MoO3-SnO2-Co3O4 composite prepared in Example 4, the content of Co3O4 was 87.83% by mass percentage, the content of SnO2 was 10.53% and the content of MoO3 was 1.64%.

[0100] Analysis using the nitrogen adsorption-desorption isotherm (BET) revealed that the catalyst prepared in Example 4 had a specific surface area of ​​132 m². 2 / g.

[0101] Example 4 also provides a flue gas purification system, which differs from Example 1 in that the catalyst loaded is different. The catalyst loaded in the flue gas purification system of Example 4 corresponds to the catalyst prepared in Example 4.

[0102] The remaining steps are the same as in Example 1, and will not be repeated here.

[0103] The flue gas purification system provided in Example 4 was used to treat simulated flue gas, which was the same as that in Example 1.

[0104] The results showed that the catalyst in Example 4 achieved a conversion rate of 98.3% for the initial CO, and after 21 hours of continuous operation, the catalyst maintained 90% of its activity.

[0105] Comparative Examples 5-6 Comparative Examples 5 and 6 respectively provide a method for preparing a composite supported carbon monoxide catalyst. The difference between them and Example 1 is that the content of tin ions in the tin source is different in step S1.

[0106] In step S1 of Comparative Example 5, the molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is 94:1:4.8.

[0107] In step S1 of Comparative Example 6, the molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is 94:1:20.

[0108] The remaining steps are the same as in Example 1, and will not be repeated here.

[0109] The catalyst prepared above comprises a complex of MoO3-SnO2-Co3O4; In the MoO3-SnO2-Co3O4 composite prepared in Comparative Example 5, the content of Co3O4 was 89.7%, the content of SnO2 was 8.63%, and the content of MoO3 was 1.71% by mass percentage.

[0110] In the MoO3-SnO2-Co3O4 composite prepared in Comparative Example 6, the content of Co3O4 was 70.5% by mass percentage, the content of SnO2 was 28.16% and the content of MoO3 was 1.34%.

[0111] Analysis using the nitrogen adsorption-desorption isotherm (BET) revealed that the catalyst prepared in Comparative Example 5 had a specific surface area of ​​159 m². 2 / g. The specific surface area of ​​the catalyst prepared in Comparative Example 6 is 110 m². 2 / g.

[0112] Comparative Examples 5 and 6 also provide a flue gas purification system, which differs from Example 1 in that the catalyst loaded is different. The catalyst loaded in the flue gas purification systems of Comparative Examples 5 and 6 are respectively the catalysts prepared in Comparative Examples 5 and 6.

[0113] The remaining steps are the same as in Example 1, and will not be repeated here.

[0114] The flue gas purification systems provided in Comparative Examples 5 and 6 were used to treat simulated flue gas, which was the same as that in Example 1.

[0115] The results showed that the catalyst in Comparative Example 5 achieved an initial CO conversion rate of 89%, and after 21 hours of continuous operation, the catalyst maintained 55% activity.

[0116] The catalyst in Comparative Example 6 achieved a conversion rate of 79% for the initial CO and maintained 43% activity after 21 hours of continuous operation.

[0117] Example 5 Example 5 provides a method for preparing a composite supported carbon monoxide catalyst. The difference between Example 5 and Example 1 is that the cobalt source used in step S1 of Example 8 is different. The cobalt source used in Example 5 was cobalt acetate.

[0118] The remaining steps are the same as in Example 1, and will not be repeated here.

[0119] The catalyst prepared above comprises a complex of MoO3-SnO2-Co3O4; Example 5 also provides a flue gas purification system, which differs from Example 1 in that the catalyst loaded is different. The catalyst loaded in the flue gas purification system of Comparative Example 8 corresponds to the catalyst prepared in Comparative Example 8.

[0120] The remaining steps are the same as in Example 1, and will not be repeated here.

[0121] Analysis using the nitrogen adsorption-desorption isotherm (BET) revealed that the catalyst prepared in Example 5 had a specific surface area of ​​85 m². 2 / g.

[0122] The flue gas purification system provided in Example 5 was used to treat simulated flue gas, which was the same as that in Example 1.

[0123] The results showed that the catalyst in Example 5 had a conversion rate of 92% for the initial CO, and its activity was 87% after 12 hours of continuous operation.

[0124] The reduced performance compared to Example 1 is due to the fact that the organic acid anions in the cobalt acetate used produce residual carbon during high-temperature decomposition, which partially blocks the pores in the catalyst structure. This leads to a decrease in the specific surface area of ​​the catalyst, directly reducing the accessible active sites for the CO oxidation reaction and resulting in a lower CO conversion rate. More importantly, these carbon residues damage the purity and homogeneity of the catalyst framework, making it more susceptible to structural degradation and sulfur poisoning in high-temperature, high-humidity, sulfur-containing atmospheres, thus exhibiting poor long-term stability. In contrast, the cobalt nitrate used in Example 1 of this invention has a lower nitrate content (NO3). - The decomposition is complete, and the products are all gaseous, which can achieve "self-purification", thus obtaining a composite metal oxide catalyst with no carbon residue, unobstructed pores and pure structure.

[0125] Comparative Example 7 Comparative Example 7 provides a method for preparing a composite supported carbon monoxide catalyst. The difference from Example 1 is that in step S2 of Comparative Example 7, mechanical stirring is used instead of ultrasonic treatment.

[0126] The remaining steps are the same as in Example 1, and will not be repeated here.

[0127] The catalyst prepared above comprises a complex of MoO3-SnO2-Co3O4; In the MoO3-SnO2-Co3O4 composite prepared in Comparative Example 7, the content of Co3O4 was 84.61% by mass, the content of SnO2 was 14.58%, and the content of MoO3 was 0.81%.

[0128] Comparative Example 7 also provides a flue gas purification system, which differs from Example 1 in that the catalyst loaded is different. The catalyst loaded in the flue gas purification system of Comparative Example 7 corresponds to the catalyst prepared in Comparative Example 7.

[0129] The remaining steps are the same as in Example 1, and will not be repeated here.

[0130] Analysis using the nitrogen adsorption-desorption isotherm (BET) revealed that the catalyst prepared in Comparative Example 7 had a specific surface area of ​​140 m². 2 / g.

[0131] The flue gas purification system provided in Comparative Example 7 was used to treat simulated flue gas, which was the same as that in Example 1.

[0132] The results showed that the catalyst in Comparative Example 7 had a conversion rate of 95% for the initial CO, and its activity was 82.1% after 6 hours of continuous operation.

[0133] The reduced effect compared to Example 1 is due to decreased uniformity of metal ion mixing during precipitation. Furthermore, detection revealed a sharp drop in the proportion of mesopores in the 5nm-15nm range to 62%, indicating that component segregation weakens the synergistic electronic effect of SnO2-MoO3. This suggests that ultrasonic cavitation plays a crucial role in atomic-level dispersion.

[0134] In summary, this invention provides a composite supported carbon monoxide catalyst and its preparation method, as well as a flue gas purification system. The catalyst comprises a MoO3-SnO2-Co3O4 composite, wherein the content of Co3O4 in the MoO3-SnO2-Co3O4 composite is 73.81%~93%, the content of SnO2 is 8%~25.06%, and the content of MoO3 is 0.3%~1.64%. This catalyst uses Co3O4 as the catalyst host, and its spinel structure contains Co... 3+ / Co 2+ Redox pairs are the main active sites in the CO oxidation reaction; however, when used alone, these active sites are easily deactivated by SO2 poisoning and the formation of cobalt sulfate. Therefore, the introduction of SnO2 not only enhances the density of acidic sites on the support surface and promotes O2 activation, but more importantly, it constructs a "high-speed electron channel" due to its high electron mobility. The key role of trace amounts of MoO3 is reflected in the dynamic oxygen regulation: during the reaction, Mo... 6+ Reversible conversion to Mo 5+ This effectively accelerates the cycling efficiency of lattice oxygen. Simultaneously, the Mo-O-Sn bonds formed at the MoO3-SnO2 interface trigger strong electronic interactions and significantly weaken the adsorption strength of SO2 at the active sites, inhibiting sulfate formation at the source. The preparation method employs a complexing agent-assisted ultrasonic co-precipitation method, dissolving cobalt, molybdenum, and tin sources in an ethanol-water solution, and precisely controlling the ratio of carboxyl groups in the complexing agent to the total content of cobalt, molybdenum, and tin ions in the precursor solution to obtain the catalyst precursor. Finally, the catalyst precursor undergoes a stepwise heat treatment to obtain a mesoporous metal oxide catalyst. This preparation method is simple, low-cost, energy-efficient, and does not emit harmful gases, making it environmentally friendly, applicable to a wide temperature range, and exhibiting excellent resistance to water and carbon dioxide toxicity.

[0135] The catalyst prepared was subjected to low temperature of 120℃ and space velocity of 30,000 h⁻¹. -1 It can achieve complete CO conversion under certain conditions; it can operate continuously for 21 hours in harsh conditions containing 240ppm SO2 and 13% H2O, with an activity retention rate of >89% (30% higher than the traditional CeO2-Co3O4 system), and is suitable for the purification of low-temperature and high-sulfur environments such as steel sintering flue gas.

[0136] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A composite supported carbon monoxide catalyst, characterized in that, The catalyst comprises a complex of MoO3-SnO2-Co3O4.

2. The composite supported carbon monoxide catalyst according to claim 1, characterized in that, In the MoO3-SnO2-Co3O4 composite, the content of Co3O4 is 73.81%~93% by mass percentage, the content of SnO2 is 8%~25.06%, and the content of MoO3 is 0.3%~1.64%.

3. A method for preparing the composite supported carbon monoxide catalyst according to claim 1 or 2, characterized in that, Includes the following steps: A cobalt source, a molybdenum source, and a tin source are provided, and the cobalt source, the molybdenum source, and the tin source are dissolved in an ethanol-water solution to obtain a precursor solution; A complexing agent is added to the precursor solution to obtain a precursor chelate complex solution; Under ultrasonic treatment conditions, a precipitant is added to the precursor chelate complex solution to obtain an ultrasonic coprecipitate; The ultrasonic coprecipitate was aged to obtain a catalyst precursor. The catalyst precursor was subjected to vacuum drying, pre-oxidation, and calcination in sequence to obtain the composite supported carbon monoxide catalyst.

4. The preparation method according to claim 3, characterized in that, The molar ratio of cobalt ions in the cobalt source, molybdenum ions in the molybdenum source, and tin ions in the tin source is (93~94.5):(0.3~1.1):(5.5~17.5).

5. The preparation method according to claim 3, characterized in that, In the step of adding a precipitant to the precursor chelate complex solution under ultrasonic treatment, the precipitant is added dropwise until the pH of the precursor chelate complex solution containing the precipitant is 8-11.

6. The preparation method according to claim 3, characterized in that, The vacuum drying process includes drying the catalyst precursor for 4 to 12 hours at a temperature of 100°C to 150°C and a pressure of -0.1 MPa to -0.02 MPa.

7. The preparation method according to claim 3, characterized in that, The pre-oxidation treatment includes: heating the vacuum-dried catalyst precursor to 300℃~400℃, holding it at 300℃~400℃ for 1h~4h, and then cooling it to 0℃~40℃; the heating rate during the pre-oxidation treatment is 2℃ / min~10℃ / min; and / or, The calcination process includes: heating the pre-oxidized catalyst precursor to 400℃~650℃, holding it at 400℃~650℃ for 3h~6h, and then cooling it to 0℃~40℃; the heating rate during the calcination process is 2℃ / min~10℃ / min.

8. The preparation method according to claim 4, characterized in that, The cobalt source includes any one or more of cobalt nitrate, cobalt acetate, cobalt chloride, and cobalt sulfate; and / or, The molybdenum source includes any one or more of ammonium molybdate, potassium molybdate, molybdenum nitrate, and molybdenum acetate; and / or, The tin source includes any one or more of stannous chloride, stannous tetrachloride, stannous nitrate, and stannous sulfate; and / or, In the ethanol-water solution, the mass percentage of ethanol is 50% to 75%; and / or, The mass ratio of the cobalt source to the ethanol-water solution is (1.5:1) to (2:1); and / or, The complexing agent includes any one or more of citric acid, acetic acid, oxalic acid, tartaric acid, and gluconic acid; and / or, The ratio of the molar mass of the carboxyl group in the complexing agent to the total molar mass of cobalt ions, molybdenum ions and tin ions in the precursor solution is (1:1) to (1:2).

9. The preparation method according to any one of claims 3 to 8, characterized in that, The precipitant includes any one or more of sodium carbonate solution, sodium bicarbonate solution, ammonia, sodium hydroxide solution, and potassium hydroxide solution; and / or, The frequency of the ultrasonic treatment is 20kHz to 60kHz, and the power of the ultrasonic treatment is 100W to 400W; and / or, The aging process takes 6 to 48 hours.

10. A flue gas purification system, characterized in that, The system is loaded with the composite supported carbon monoxide catalyst as described in claim 1 or 2, and the system is equipped with an air velocity control module. The reaction space velocity in the airspeed control module is 25,000 h. -1 ~35000h -1 ; The system is suitable for processing flue gas from steel sintering pellets with a temperature of 100℃~180℃, a sulfur content of ≤500ppm, and a moisture content of ≤15%.

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