Multi-metal oxide low-temperature desulfurization and denitrification catalyst and preparation method thereof

Abstract

The invention provides a multi-metal oxide low-temperature desulfurization and denitrification catalyst and a preparation method thereof, and relates to the field of catalyst preparation. According to the catalyst, TiO2 is used as a catalyst carrier, Fe2O3, MnO2, CoO2, CeO2 and V2O5 are used as active components, and the surface of the catalyst carrier is coated with the active components; during preparation, a deposition-precipitation method is adopted, and the components are subjected to fractional precipitation or impregnation and then roasted to obtain the catalyst. By adopting the preparation method disclosed by the invention, the prepared multi-metal oxide low-temperature desulfurization and denitrification catalyst has good performance of removing nitrogen oxides and sulfides, the catalyst is good in stability, the preparation process is simple, and secondary pollution is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst preparation, and in particular to a multi-metal oxide low-temperature desulfurization and denitration catalyst and a preparation method thereof. Background Art

[0002] Coal is one of the main energy sources at this stage. When it is used, sulfur oxides and nitrogen oxides are continuously emitted. Among them, SO2 is easily soluble in water to form H2SO3, which is further oxidized to H2SO4 to form acid rain. Acid rain seriously damages the ecological environment and corrodes building steel. Direct emission without treatment will cause huge economic losses. NOx, mainly NO and NO2, is an important cause of photochemical smog and acid rain.

[0003] At present, air pollution in my country is mainly flue gas pollution, which is manifested as acid rain and photochemical smog caused by the emission of SO2 and NOx. Sulfide and nitrogen oxides will not only cause soil acidification, slow growth of plants and animals, acidification of water bodies, corrosion of buildings, etc., but also endanger human health; for example, SO2 has a strong irritating effect on the mucous membrane and conjunctiva of the upper respiratory tract, causing pneumonia, bronchitis, and even pulmonary edema and respiratory paralysis of respiratory organs. The harm of NOx to the human body is manifested in that NO combines with hemoglobin in the blood, causing methemoglobinemia, etc., as well as damage to the central nervous system, symptoms such as paralysis and spasm, and even lesions of respiratory organs such as lungs in severe cases; NO2 can also cause diseases such as asthma. Therefore, it is urgent to reduce and control the emission of SO2 and NOx in flue gas.

[0004] Sulfur dioxide and nitrogen oxides exist in flue gas at the same time. If they are removed separately during the removal process, it will bring about problems such as large floor space, many equipment, complex operation, and poor economic benefits. Since both gases are acidic oxides, they can be designed to be removed simultaneously. At present, the integration of flue gas desulfurization and denitrification mainly consists of wet desulfurization and denitrification, dry desulfurization and denitrification, and semi-dry desulfurization and denitrification. Among them, the wet removal effect is better, but the waste liquid pollution is serious; the dry removal operation cost is high; the semi-dry method has the advantages of both dry and wet methods, but there are problems such as unstable operation.

[0005] The prior art proposes a variety of catalysts for desulfurization and denitration, such as the flue gas low-temperature synchronous desulfurization and denitration catalyst of patent CN103691476B, which uses mesoporous SBA-15, nano titanium dioxide (anatase type) and various metal oxides (Mn, V, Cr, Ce, W, Mo) and ammonia and deionized water to mix and prepare the catalyst precursor, and uses reinforcing agent glass fiber, cross-linking agent methacrylate-2-hydroxyethyl ester, surfactant stearic acid and thermal stability for secondary mixing and molding, and calcination to prepare a porous catalyst. Patent CN105642339B discloses a simultaneous desulfurization and denitration catalyst without reducing gas, which uses a carrier ZSM-5 molecular sieve, active components are CuO, K2O, CoO, Ni2O3, V2O5 and WO3, and adopts a one-time or multiple impregnation method to obtain the catalyst after drying and calcination. Summary of the invention

[0006] The purpose of the present invention is to provide a multi-metal oxide low-temperature desulfurization and denitrification catalyst and a preparation method thereof. First, a precipitation method is used to precipitate part of the active components in steps, and then the remaining active components are impregnated by an impregnation method to finally obtain a catalyst. The method has simple procedures, readily available raw materials, a stable catalyst structure, excellent catalytic performance, and does not cause secondary pollution.

[0007] To achieve the above object, the present invention proposes the following technical solutions:

[0008] In the first aspect, a multi-metal oxide low-temperature desulfurization and denitrification catalyst is provided, comprising: a catalyst carrier, TiO2; active components, Fe2O3, MnO2, CoO2, CeO2 and V2O5; the active components are coated on the surface of the catalyst carrier, and the molar ratio of each metal element in the catalyst is Ti:Mn:Co:Ce:Fe:V=100:(6-8):(1-2):(1-2):(1-3):(1-3); preferably, the molar ratio of each metal element is: Ti:Mn:Co:Ce:Fe:V=100:6:2:2:3:3.

[0009] A method for preparing the above-mentioned multi-metal oxide low-temperature desulfurization and denitrification catalyst is provided. The method first distributes and precipitates to obtain a catalyst carrier TiO2 and a metal salt mixture corresponding to each active component Fe2O3, MnO2, CoO2, and CeO2, and then uses an impregnation method to load the metal salt corresponding to V2O5 on the surface of the first calcined product after the metal salt mixture is calcined. Finally, the first calcined product with the metal salt corresponding to V2O5 on the surface is calcined for a second time to obtain a multi-metal oxide low-temperature desulfurization and denitrification catalyst.

[0010] Furthermore, the method comprises the following steps:

[0011] 1) dissolving Ti salt and Fe salt weighed in proportion and mixing with excess alkaline precipitant for reaction, maintaining the pH of the reaction solution at 9-10 until the reaction is completed to obtain a first reaction solution;

[0012] 2) using a sedimentation precipitation method, adding proportionally weighed Mn salt, Co salt, and Ce salt to the first reaction solution in sequence to continue the reaction, maintaining the pH of the reaction solution at 9-10 until the reaction is completed to obtain a second reaction solution;

[0013] 3) aging, washing, drying, calcining, and then forming tablets of the solid product of the second reaction solution to obtain a first calcined product;

[0014] 4) impregnating an equal volume of the first calcined product into a mixed solution of ammonium metavanadate and acid configured in proportion, and standing for 3-4 hours to obtain a third reaction solution;

[0015] 5) washing, drying and calcining the solid product of the third reaction solution to obtain a multi-metal oxide low-temperature desulfurization and denitrification catalyst.

[0016] Furthermore, in the step 1), the alkaline precipitant is Na2CO3, NaHCO3, K2CO3 or KHCO3.

[0017] Furthermore, the aging time of the solid product of the second reaction solution in step 3) is 4-6 hours.

[0018] Furthermore, the standard for washing the solid product of the second reaction solution in step 3) is to wash until the solution pH is 7.0 and no blue color is developed after adding five drops of diphenylamine sulfuric acid solution.

[0019] Furthermore, the acid in step 4) is oxalic acid.

[0020] Furthermore, the drying standards of the product in step 3) and step 5) are: drying temperature 100-120° C., and weight loss after drying 80-82%.

[0021] Furthermore, the conditions for calcining the product in step 5) are: calcination temperature 450-480° C., calcination time 4-6 h.

[0022] It can be seen from the above technical solutions that the technical solutions of the present invention have the following beneficial effects:

[0023] The present invention discloses a multi-metal oxide low-temperature desulfurization and denitrification catalyst and a preparation method thereof, wherein the catalyst uses TiO2 as a catalyst carrier, and Fe2O3, MnO2, CoO2, CeO2 and V2O5 as active components, the active components are coated on the surface of the catalyst carrier, and the molar ratio of each metal element in the catalyst is Ti:Mn:Co:Ce:Fe:V=100:(6-8):(1-2):(1-2):(1-3):(1-3); during preparation, firstly, a catalyst carrier TiO2 and each active component Fe2O3, MnO2, CoO2, CeO2 and V2O5 are obtained by distributed precipitation; A metal salt mixture corresponding to V2O5 is prepared, and a metal salt mixture corresponding to V2O5 is loaded on the surface of a first calcined product after the metal salt mixture is calcined by an impregnation method. Finally, the first calcined product with the metal salt corresponding to V2O5 loaded on the surface is calcined for a second time to obtain a multi-metal oxide low-temperature desulfurization and denitrification catalyst. The multi-metal oxide low-temperature desulfurization and denitrification catalyst prepared by the preparation method disclosed in the present invention does not form a solid solution compound when it is calcined. When used in desulfurization and denitrification reactions, it has good performance in removing nitrogen oxides and sulfides. A large number of experiments have shown that the catalyst of the present invention has good stability and no secondary pollution.

[0024] It should be appreciated that all combinations of the foregoing concepts, as well as additional concepts described in greater detail below, may be considered to be part of the inventive subject matter of the present disclosure, provided such concepts are not mutually inconsistent.

[0025] The foregoing and other aspects, embodiments and features of the present invention can be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as the features and / or beneficial effects of the exemplary embodiments, will be apparent from the following description or learned from the practice of the specific embodiments according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For clarity, not every component is labeled in every figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0027] Figure 1 This is a flow chart of the method for preparing the multi-metal oxide low-temperature desulfurization and denitrification catalyst of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meaning understood by people with general skills in the field to which the present invention belongs.

[0029] The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "a", "an" or "the" and other similar words do not indicate a quantitative limitation, but indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before "include" or "comprise" cover the features, wholes, steps, operations, elements and / or components listed after "include" or "comprise", and do not exclude the existence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0030] Based on the current flue gas desulfurization and denitrification integration mainly consisting of wet desulfurization and denitrification, dry desulfurization and denitrification, and semi-dry desulfurization and denitrification; although the dry desulfurization and denitrification operation cost is high, it has always been the research direction of desulfurization and denitrification because it does not produce waste liquid and has stable effect. The present invention aims to propose a multi-metal oxide low-temperature desulfurization and denitrification catalyst for dry desulfurization and denitrification and a preparation method thereof. The catalyst has a simple process, is efficient and stable in desulfurization and denitrification, has low cost, and does not produce secondary pollution.

[0031] Specifically, the preparation method of the multi-metal oxide low-temperature desulfurization and denitrification catalyst comprises the following steps: 1) dissolving Ti salt and Fe salt weighed in proportion and mixing with excess alkaline precipitant for reaction, maintaining the pH of the reaction solution at 9-10 until the reaction is completed to obtain a first reaction solution; wherein the alkaline precipitant is Na2CO3, NaHCO3, K2CO3 or KHCO3; 2) using a sedimentation precipitation method, adding Mn salt, Co salt and Ce salt weighed in proportion to the first reaction solution in sequence to continue the reaction, maintaining the pH of the reaction solution at 9-10 until the reaction is completed to obtain a second reaction solution; wherein, when adding the next metal salt, it is necessary to stir the previous metal salt for reaction for 0.5-1h; 3) aging the solid product of the second reaction solution for 4-6h, washing, After drying and calcining, the first calcined product is formed into a sheet; 4) the first calcined product is immersed in an equal volume of a mixed solution of ammonium metavanadate and acid configured in proportion, and allowed to stand for 3-4 hours to obtain a third reaction solution; wherein the acid is oxalic acid; 5) the solid product of the third reaction solution is washed, dried, and calcined to obtain a multi-metal oxide low-temperature desulfurization and denitrification catalyst; the catalyst comprises: a catalyst carrier, TiO2; active components, Fe2O3, MnO2, CoO2, CeO2 and V2O5; the active components are coated on the surface of the catalyst carrier, and the molar ratio of each metal element in the catalyst is Ti:Mn:Co:Ce:Fe:V=100:(6-8):(1-2):(1-2):(1-3):(1-3). In the above steps, Ti salt, Fe salt, Mn salt, Co salt, and Ce salt are all nitrates.

[0032] The multi-metal oxide low-temperature desulfurization and denitrification catalyst and its preparation method disclosed in the present invention are further specifically introduced below in conjunction with the specific process and embodiments shown in the accompanying drawings.

[0033] The multi-metal oxide low-temperature desulfurization and denitrification catalyst disclosed in the present invention adopts titanium dioxide as a catalyst carrier and uses manganese, cobalt, cerium, iron and vanadium as active ingredients. During preparation, the multi-metal oxide does not form a solid solution compound after roasting. The advantage of this method is that the active components are precipitated step by step by a precipitation method, and then the active components are impregnated by an impregnation method to finally obtain a catalyst. The preparation parameters of the optimal catalyst are determined through a large number of examples as follows, and the optimal catalyst has a good desulfurization and denitrification effect.

[0034] Example 1

[0035] Add the mixed solution containing Ti(NO3)4 and Fe(NO3)3 to water in parallel with Na2CO3 solution, stir and maintain for 0.5-1h. Add Mn(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Co(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Mn:Co:Ce:Fe=100:8:1:1:1. The precipitate was aged for 4 hours, washed until it was blue with five drops of diphenylamine sulfuric acid solution, dried at 120°C until it lost 80% of its weight, programmed to rise to 460°C for calcination for 4 hours, and then formed into tablets. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the tableted catalyst was immersed in the ammonium oxalic acid metavanadate solution, immersed in equal volumes for 3 hours, washed, calcined at 450°C for 3 hours, and decomposed to obtain Ti:Mn:Co:Ce:Fe:V=100:8:1:1:1:2 catalyst I.

[0036] Example 2

[0037] Add the mixed solution containing Ti(NO3)4 and Fe(NO3)3 and NaHCO3 solution to water in parallel, stir and maintain for 0.5-1h. Add Mn(NO3)2 solution to the above solution, add NaHCO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Co(NO3)2 solution to the above solution, add NaHCO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add NaHCO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Mn:Co:Ce:Fe=100:6:1.5:2:1. The precipitate was aged for 4 hours, washed until it was blue with five drops of diphenylamine sulfuric acid solution, dried at 120°C until it lost 82% of its weight, programmed to rise to 480°C for calcination for 4 hours, and then formed into tablets. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the tableted catalyst was immersed in the ammonium oxalic acid metavanadate solution, immersed in equal volumes for 3 hours, washed, calcined at 460°C for 3 hours, and decomposed to obtain Ti:Mn:Co:Ce:Fe:V=100:6:1.5:2:1:2 catalyst II.

[0038] Example 3

[0039] Add the mixed solution containing Ti(NO3)4 and Fe(NO3)3 and K2CO3 solution to water in parallel, stir and maintain for 0.5-1h. Add Mn(NO3)2 solution to the above solution, add K2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Co(NO3)2 solution to the above solution, add K2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add K2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Mn:Co:Ce:Fe=100:8:1:1:1. The precipitate was aged for 4 hours, washed until it was blue with five drops of diphenylamine sulfuric acid solution, dried at 120°C until it lost 80% of its weight, programmed to rise to 460°C for calcination for 4 hours, and then cut into pieces. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the cut-piece catalyst was immersed in the ammonium oxalic acid metavanadate solution, immersed in equal volumes for 3 hours, washed, calcined at 450°C for 3 hours, and decomposed to obtain Ti:Mn:Co:Ce:Fe:V=100:8:1:1:1:1 catalyst III.

[0040] Example 4

[0041] Add the mixed solution containing Ti(NO3)4 and Fe(NO3)3 and KHCO3 solution to water in parallel, stir and maintain for 0.5-1h. Add Mn(NO3)2 solution to the above solution, add KHCO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Co(NO3)2 solution to the above solution, add NaHCO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add KHCO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Mn:Co:Ce:Fe=100:6:2:2:3. The precipitate was aged for 4 hours, washed until it was blue with five drops of diphenylamine sulfuric acid solution, dried at 120°C until it lost 80% of its weight, programmed to rise to 460°C for calcination for 4 hours, and then formed into tablets. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the tableted catalyst was immersed in the ammonium oxalic acid metavanadate solution, immersed in equal volumes for 4 hours, washed, calcined at 450°C for 5 hours, and decomposed to obtain Ti:Mn:Co:Ce:Fe:V=100:6:2:2:3:3 catalyst IV.

[0042] Example 5

[0043] Add the mixed solution containing Ti(NO3)4 and Fe(NO3)3 and K2CO3 solution to water in parallel, stir and maintain for 0.5-1h. Add Mn(NO3)2 solution to the above solution, add KHCO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Co(NO3)2 solution to the above solution, add NaHCO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add KHCO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Mn:Co:Ce:Fe=100:8:2:2:3. The precipitate was aged for 4 hours, washed until it was blue with five drops of diphenylamine sulfuric acid solution, dried at 120°C until it lost 81% of its weight, programmed to 480°C for calcination for 6 hours, and then cut into pieces. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the cut-piece catalyst was immersed in the ammonium oxalic acid metavanadate solution, immersed in equal volumes for 3 hours, washed, calcined at 450°C for 4 hours, and decomposed to obtain Ti:Mn:Co:Ce:Fe:V=100:8:2:2:3:3 catalyst V.

[0044] Example 6

[0045] Add the mixed solution containing Ti(NO3)4 and Fe(NO3)3 and K2CO3 solution to water in parallel, stir and maintain for 0.5-1h. Add Mn(NO3)2 solution to the above solution, add K2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Co(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add K2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Mn:Co:Ce:Fe=100:6:1:1:3. The precipitate was aged for 4 hours, washed until it was blue with five drops of diphenylamine sulfuric acid solution, dried at 120°C until it lost 81% of its weight, programmed to 480°C for calcination for 4 hours, and then cut into pieces. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the cut-piece catalyst was immersed in an ammonium oxalic acid metavanadate solution, immersed in equal volumes for 4 hours, washed, calcined at 450°C for 4 hours, and decomposed to obtain Ti:Mn:Co:Ce:Fe:V=100:6:1:1:3:3 catalyst VI.

[0046] Example 7

[0047] Add the mixed solution containing Ti(NO3)4 and Fe(NO3)3 to water in parallel with NaHCO3 solution, stir and maintain for 0.5-1h. Add Mn(NO3)2 solution to the above solution, add NaHCO3 solution, maintain the pH of the solution at 9-10, continue stirring and maintain for 0.5-1h. Add Co(NO3)2 solution to the above solution, add NaHCO3 solution, maintain the pH of the solution at 9-10, continue stirring and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add NaHCO3 solution, maintain the pH of the solution at 9-10, continue stirring and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Mn:Co:Ce:Fe=100:6:1:1:1. The precipitate was aged for 4 hours, washed until it was blue with five drops of diphenylamine sulfuric acid solution, dried at 120°C until it lost 81% of its weight, programmed to rise to 480°C for calcination for 6 hours, and then cut into pieces. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the formed catalyst was immersed in the ammonium oxalic acid metavanadate solution, immersed in equal volumes for 3.5 hours, washed, calcined at 450°C for 4 hours, and decomposed to obtain Ti:Mn:Co:Ce:Fe:V=100:6:1:1:1:1 catalyst VII.

[0048] Comparative Example 1

[0049] Add the mixed solution containing Ti(NO3)4 and Fe(NO3)3 to water in parallel with Na2CO3 solution, stir and maintain for 0.5-1h. Add Co(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Co:Ce:Fe=100:1:1:1. The precipitate is aged for 4h, washed until it is blue with five drops of diphenylamine sulfuric acid solution, dried at 120℃ until the weight loss is 80%, programmed to 460℃ for calcination for 4 hours, and then formed into sheets. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the tableted catalyst was immersed in the ammonium oxalic acid metavanadate solution for 4 hours, washed, calcined at 450°C for 3 hours, and decomposed to obtain Ti:Co:Ce:Fe:V=100:1:1:1:2 catalyst A.

[0050] Comparative Example 2

[0051] Add the mixed solution containing Ti(NO3)4 and Fe(NO3)3 to water in parallel with K2CO3 solution, stir and maintain for 0.5-1h. Add Co(NO3)2 solution to the above solution, add K2CO3 solution, maintain the pH of the solution at 9-10, continue stirring and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add K2CO3 solution, maintain the pH of the solution at 9-10, continue stirring and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Co:Ce:Fe=100:2:2:3. The precipitate is aged for 4h, washed until it is blue with five drops of diphenylamine sulfuric acid solution, dried at 120℃ until the weight loss is 81%, programmed to 480℃ for calcination for 6 hours, and then formed into sheets. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the tableted catalyst was immersed in the ammonium oxalic acid metavanadate solution for 3 hours, washed, calcined at 450°C for 4 hours, and decomposed to obtain catalyst B with a metal element ratio of Ti:Co:Ce:Fe:V=100:2:2:3:3.

[0052] Comparative Example 3

[0053] Add the mixed solution containing Ti(NO3)4 and Fe(NO3)3 to water in parallel with Na2CO3 solution, stir and maintain for 0.5-1h. Add Mn(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Mn:Ce:Fe=100:8:1:1. The precipitate is aged for 4h, washed until it is blue with five drops of diphenylamine sulfuric acid solution, dried at 120℃ until the weight loss is 80%, programmed to 460℃ for calcination for 4 hours, and then formed into sheets. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the tableted catalyst was immersed in the ammonium oxalic acid metavanadate solution for 3 hours, washed, calcined at 450°C for 3 hours, and decomposed to obtain catalyst C with a metal element ratio of Ti:Mn:Ce:Fe:V=100:8:1:1:2.

[0054] Comparative Example 4

[0055] Add the mixed solution containing Ti(NO3)4 and Fe(NO3)3 to water in parallel with Na2CO3 solution, stir and maintain for 0.5-1h. Add Mn(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Co(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Mn:Co:Fe=100:8:1:1. The precipitate is aged for 4h, washed until it is blue with five drops of diphenylamine sulfuric acid solution, dried at 120℃ until the weight loss is 80%, programmed to 460℃ for calcination for 4 hours, and then formed into sheets. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the tableted catalyst was immersed in the ammonium oxalic acid metavanadate solution for 3 hours, washed, calcined at 450°C for 3 hours, and decomposed to obtain catalyst D with a metal element composition of Ti:Mn:Co:Fe:V=100:8:1:1:2.

[0056] Comparative Example 5

[0057] Add the solution containing Ti(NO3)4 and Na2CO3 solution to water in parallel, stir and maintain for 0.5-1h. Add Mn(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Co(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue to stir and maintain for 0.5-1h. The molar ratio of the constituent elements of the catalyst is Ti:Mn:Co:Ce=100:8:1:1. The precipitate is aged for 4h, washed until it is blue with five drops of diphenylamine sulfuric acid solution, dried at 120℃ until the weight loss is 80%, programmed to 460℃ for calcination for 4 hours, and then formed into sheets. Oxalic acid and ammonium metavanadate solution were prepared in a molar ratio of 1:2, and the tableted catalyst was immersed in the ammonium oxalic acid metavanadate solution for 3 hours, washed, calcined at 450°C for 3 hours, and decomposed to obtain catalyst E with metal element composition of Ti:Mn:Co:Ce:V=100:8:1:1:2.

[0058] Comparative Example 6

[0059] Add a mixed solution containing Ti(NO3)4 and Fe(NO3)3 to water in parallel with a Na2CO3 solution, stir and maintain for 0.5-1h; add Mn(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue stirring and maintain for 0.5-1h. Add Ce(NO3)2 solution to the above solution, add Na2CO3 solution, maintain the pH of the solution at 9-10, continue stirring and maintain for 0.5-1h. Aging of the precipitate for 4h, washing until five drops of diphenylamine sulfuric acid solution are blue, drying at 120℃ until the weight loss is 80%, program heating to 460℃ and roasting for 4 hours, decomposing to obtain a catalyst F with a metal component molar ratio of Ti:Mn:Co:Ce:Fe=100:8:1:1:1.

[0060] Catalyst performance evaluation

[0061] Catalysts I-VII and AF were loaded in fixed bed tubular reactors respectively. The reaction conditions were as follows: pressure 0.2 MPa, gas composition SO2 800 ppm, NO 600 ppm, NH3 900 ppm, O2 volume 5%, nitrogen as balance gas, space velocity 5000 h -1 , reaction temperature 240℃, test SO2 and NO outlet concentrations.

[0062] Table 1 Catalyst performance test data

[0063]

[0064]

[0065] As can be seen from Table 1, Examples 1-7 show that the catalysts prepared by the present invention with a metal element ratio of Ti:Mn:Co:Ce:Fe:V=100:(6-8):(1-2):(1-2):(1-3):(1-3) all have excellent desulfurization and denitrification effects when used, and have high removal efficiency after running for a set time; this indicates that the catalyst of the present invention still has high desulfurization and denitrification performance after long-term operation, indicating that the catalyst has good removal performance. The removal efficiency of the catalysts A and B without Mn obtained in Comparative Examples 1 and 2 is low after running for 1h and 4h, indicating that the desulfurization and denitrification performance is not good without Mn element; Comparative Examples 3-6 are catalysts without Co, Ce, Fe and V, respectively, and the removal efficiency of sulfur and nitrate is poor when used, which indicates that the reason why the catalyst of the present invention has excellent desulfurization and denitrification efficiency is the synergistic effect brought about when each metal element forms active sites and combines with sulfur dioxide and nitrogen oxides.

[0066] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A multi-metal oxide low-temperature desulfurization and denitrification catalyst, characterized in that: include: Catalyst support, TiO2; Active components, Fe2O3, MnO2, CoO2, CeO2 and V2O5; The active components are coated on the surface of the catalyst carrier, and the molar ratio of the metal elements in the catalyst is Ti:Mn:Co:Ce:Fe:V=100:(6-8):(1-2):(1-2):(1-3):(1-3).

2. The method for preparing a multi-metal oxide low-temperature desulfurization and denitrification catalyst according to claim 1, characterized in that: First, a catalyst carrier TiO2 and a metal salt mixture corresponding to each active component Fe2O3, MnO2, CoO2, and CeO2 are obtained by distributed precipitation. The metal salt corresponding to V2O5 is loaded on the surface of the first calcined product after the metal salt mixture is calcined by an impregnation method. Finally, the first calcined product with the metal salt corresponding to V2O5 loaded on the surface is calcined for a second time to obtain a multi-metal oxide low-temperature desulfurization and denitrification catalyst.

3. The method for preparing a multi-metal oxide low-temperature desulfurization and denitrification catalyst according to claim 2, characterized in that: The steps include: 1) dissolving Ti salt and Fe salt weighed in proportion and mixing with excess alkaline precipitant for reaction, maintaining the pH of the reaction solution at 9-10 until the reaction is completed to obtain a first reaction solution; 2) using a sedimentation precipitation method, adding proportionally weighed Mn salt, Co salt, and Ce salt to the first reaction solution in sequence to continue the reaction, maintaining the pH of the reaction solution at 9-10 until the reaction is completed to obtain a second reaction solution; 3) aging, washing, drying, calcining, and then tableting the solid product of the second reaction solution to obtain a first calcined product; 4) impregnating an equal volume of the first calcined product into a mixed solution of ammonium metavanadate and an acid configured in proportion, and standing for 3-4 hours to obtain a third reaction solution; 5) washing, drying and calcining the solid product of the third reaction solution to obtain a multi-metal oxide low-temperature desulfurization and denitrification catalyst.

4. The method for preparing a multi-metal oxide low-temperature desulfurization and denitrification catalyst according to claim 3, characterized in that: In the step 1), the alkaline precipitant is Na2CO3, NaHCO3, K2CO3 or KHCO3.

5. The method for preparing a multi-metal oxide low-temperature desulfurization and denitrification catalyst according to claim 3, characterized in that: The aging time of the solid product of the second reaction solution in step 3) is 4-6 hours.

6. The method for preparing a multi-metal oxide low-temperature desulfurization and denitrification catalyst according to claim 3, characterized in that: The standard for washing the solid product of the second reaction solution in step 3) is to wash until the solution pH is 7.0 and no blue color is developed after adding five drops of diphenylamine sulfuric acid solution.

7. The method for preparing a multi-metal oxide low-temperature desulfurization and denitrification catalyst according to claim 3, characterized in that: The acid in step 4) is oxalic acid.

8. The method for preparing a multi-metal oxide low-temperature desulfurization and denitrification catalyst according to claim 3, characterized in that: The drying standards of the product in step 3) and step 5) are: drying temperature 100-120° C., and weight loss after drying 80-82%.

9. The method for preparing a multi-metal oxide low-temperature desulfurization and denitrification catalyst according to claim 3, characterized in that: The conditions for calcining the product in step 5) are: calcination temperature 450-480° C., calcination 4-6 hours.

10. The method for preparing a multi-metal oxide low-temperature desulfurization and denitrification catalyst according to claim 3, characterized in that: The molar ratio of each metal element in the multi-metal oxide low-temperature desulfurization and denitrification catalyst is: Ti:Mn:Co:Ce:Fe:V=100:6:2:2:3:3.

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