Catalyst for CO purification in coal chemical tail gas, preparation method and application

Abstract

The present invention belongs to the technical field of coal chemical tail gas treatment, and specifically relates to a catalyst for the catalytic oxidation of CO in the treatment of low-temperature methanol-washed sulfur-containing tail gas from coal chemical plants. More particularly, it relates to a honeycomb ceramic monolithic catalyst and its preparation method. The catalyst for CO purification from coal chemical tail gas described in the present invention uses platinum as the main active component, supplemented by a copper-manganese active component. The copper-manganese-based active component is combined with a precious metal platinum active component, utilizing its excellent low-temperature activity, as well as its tolerance and removal ability for sulfides. The catalyst exhibits excellent low-temperature catalytic oxidation activity for CO, completes conversion at a temperature lower than that of imported catalysts, and can tolerate trace sulfur in low-temperature methanol-washed tail gas from the coal chemical industry, meeting the technical requirements for the catalytic oxidation of CO in the aforementioned sulfur-containing tail gas.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal chemical tail gas treatment, and specifically relates to a catalyst for catalytic oxidation of CO in low-temperature methanol-washed sulfur-containing tail gas of a coal chemical plant, and more particularly to a honeycomb ceramic monolithic catalyst and a preparation method thereof. Background Art

[0002] Countries around the world have enacted laws and established VOCs emission standards to control VOCs emissions.

[0003] my country's environmental protection emission standards, such as the "Comprehensive Emission Standard of Air Pollutants" (GB16297-1996) and the "Petroleum Refining Industry Pollutant Emission Standard" (GB31570-2015), also stipulate basic requirements for pollutant emissions.

[0004] Currently, there are two main methods for treating VOC waste gas: recovery and destruction. Recovery involves separating VOCs through physical methods using pressure, temperature, selective adsorbents, and selective permeable membranes. These include carbon adsorption, pressure swing adsorption, condensation, and membrane separation technologies. Destruction involves converting volatile organic compounds into carbon dioxide and water through chemical or biochemical reactions, such as catalysts, heat, or microorganisms. These technologies include thermal combustion, catalytic oxidation, biological oxidation, and integrated technologies. Among these pollution control technologies, those that have been extensively researched and widely adopted include thermal destruction, adsorption, absorption, and condensation. Newer control technologies developed in recent years include catalytic oxidation, biofilm, ozone decomposition, corona, and plasma decomposition.

[0005] As early as 1840, Davy used catalytic oxidation technology (also known as catalytic combustion technology) in his research on the catalytic effect of platinum wire on the flameless combustion reaction of fuel and air mixture. Since then, theoretical research on catalytic oxidation has developed rapidly, and applied research has also achieved remarkable results. The principle of treating VOCs based on catalytic oxidation is to use a catalyst to make the combustible substances in the exhaust gas burn flamelessly at a lower temperature, and then oxidize and decompose the organic exhaust gas into carbon dioxide and water while releasing heat. This method has the characteristics of low auxiliary equipment cost, no secondary pollution, and high VOCs removal rate. It has become the main technical solution for VOCs treatment and one of the most promising treatment processes in this field.

[0006] In catalytic oxidation technology, catalysts are a key factor, with their catalytic performance decisively impacting the progress of the catalytic oxidation process. Consequently, the development of high-performance catalysts generates numerous publications and patent applications each year, with developed catalysts entering the market. Catalytic performance is continuously improving throughout this process, and catalyst additives and supports are also continuously developing and improving. Generally, catalysts can be categorized into four categories based on their active components: precious metal catalysts, transition metal oxide catalysts, spinel catalysts, and perovskite catalysts.

[0007] The gas purification unit at the Second Fertilizer Plant of Sinopec Qilu Branch uses Linde's low-temperature methanol scrubbing technology to absorb CO2 and H2S from the shifted and non-shifted gases of the coal-to-syngas plant, thereby purifying the process gas. The specific process flow is as follows: Process gas from the gasification unit undergoes shift and methanation reactions on one side before entering absorption tower C2201. The other, non-shifted gas, enters absorption tower C2202, where low-temperature methanol absorbs CO2 and H2S from each gas stream. Due to the inherent solubility of CO and H2 in low-temperature methanol, CO inevitably enters the methanol recovery process along with the methanol. The methanol, having absorbed CO2, H2S, CO, and H2, first enters a medium-pressure flash evaporation system, where a reduced-pressure flash evaporation process recovers most of the CO and H2. The methanol then enters a CO2 desorption tower C2203, where the CO2 is desorbed through reduced pressure and nitrogen stripping, resulting in the CO2 tail gas. Since incomplete flash-evaporation of CO is also partially desorbed during the desorption process, CO is present in the tail gas. After cold recovery, the tail gas enters the tail gas scrubber C2206 and is then discharged into the boiler stack. Typically, the CO concentration designed for the Linde low-temperature methanol scrubbing process is 0.58% (v / v). With the continuous optimization of this unit in recent years, the CO concentration can be reduced to the ultimate level of 0.4% (v / v).

[0008] To further improve exhaust gas purification efficiency, the Second Fertilizer Plant completed the construction of an RCO unit in 2020. This unit utilizes a three-body regenerative catalytic oxidation (RCO) system, with catalytic oxidation as its core technology, to treat carbon monoxide, hydrogen, and other pollutants in exhaust gas. Analysis indicates that since exhaust gas primarily consists of CO₂, N₂, CO, H₂, and trace amounts of COS and H₂S, combustibles in the exhaust gas react with O₂ under the action of a catalyst, producing harmless water and carbon dioxide, thereby purifying the exhaust gas. The RCO unit utilizes the NHH-124 catalyst developed by Japan's Nichia Corporation, which uses platinum as the active component. The catalyst is designed to operate at a temperature of 310-550°C and has a theoretical service life of four years. However, in actual operation, the catalyst's activity has significantly decreased, requiring the operating temperature to be gradually increased from the initial 310°C to 390°C after three months of operation. Literature review and laboratory simulations indicate that platinum-based catalysts are sensitive to sulfur, and that sulfides in exhaust gas can significantly degrade catalyst performance. Therefore, the development of high-performance catalysts suitable for the catalytic oxidation treatment of CO in coal chemical tail gas has positive significance for the treatment of coal chemical tail gas. Summary of the Invention

[0009] To this end, the technical problem to be solved by the present invention is to provide a honeycomb ceramic monolithic catalyst for catalytic oxidation of CO in the low-temperature methanol-washed sulfur-containing tail gas of a coal chemical plant, wherein the catalyst has high catalytic efficiency and high overall performance;

[0010] The second technical problem to be solved by the present invention is to provide a preparation method and application of the above catalyst.

[0011] To solve the above technical problems, the present invention provides a method for preparing a catalyst for purifying CO from coal chemical tail gas, comprising the following steps:

[0012] (1) preparing an aluminum salt solution by preparing a water-soluble aluminum salt, and immersing a monolithic porous support in the aluminum salt solution for aluminum loading, followed by drying and calcining to form an aluminum oxide coating having a large specific surface area;

[0013] (2) preparing a water-soluble copper-manganese salt to form a copper-manganese salt solution, and partially immersing the support treated in step (1) in the copper-manganese salt solution to load copper and manganese, followed by drying to form a support partially loaded with copper and manganese;

[0014] (3) preparing a platinum salt solution using a water-soluble platinum salt, and immersing the portion of the support treated in step (2) that is not loaded with copper and manganese in the platinum salt solution for platinum loading, followed by drying and calcination to decompose the active metal salts into oxides, thereby obtaining the product.

[0015] Specifically, in step (1), the monolithic porous carrier comprises cordierite honeycomb ceramics.

[0016] Preferably, the cordierite honeycomb ceramic monolithic carrier has a size of 150 mm*150 mm*50 mm, a bulk density of 0.60-0.75 kg / L, a pore density of 200, and a specific surface area of ​​1.7-2.0 m 3 / g, pore volume 22-25cm 3 / g of cordierite carrier.

[0017] Specifically, in the method for preparing the catalyst for purifying CO from coal chemical tail gas, in step (1):

[0018] In the aluminum salt solution, the concentration of Al ions is 2-2.5 mol / L;

[0019] The aluminum salt includes aluminum nitrate.

[0020] Specifically, in step (1), the temperature of the calcination step is 500-600°C.

[0021] Preferably, in step (1), the dipping step is preferably performed for 30-45 minutes.

[0022] Specifically, in the method for preparing the catalyst for purifying CO from coal chemical tail gas, in step (2):

[0023] In the copper-manganese salt solution, the total concentration of Cu and Mn ions is 1.2-1.5 mol / L;

[0024] In the copper-manganese salt solution, the concentration ratio of Cu and Mn ions is 1:1-1:0.6;

[0025] The manganese salt includes manganese nitrate and / or manganese acetate;

[0026] The copper salt includes copper nitrate and / or copper sulfate.

[0027] It should be noted that although water-soluble manganese salts include manganese chloride, manganese nitrate, manganese sulfate, and manganese acetate, and copper salts include copper chloride and copper nitrate, the catalyst of the present invention also needs to load the active component platinum. To avoid contamination of platinum by chloride ions, copper chloride and manganese chloride are not selected. Similarly, manganese sulfate has a high decomposition temperature and is not suitable for this catalyst to avoid damaging the large specific surface area of ​​alumina.

[0028] Preferably, the immersion time is controlled within 60-90 minutes.

[0029] Specifically, in the method for preparing the catalyst for purifying CO from coal chemical tail gas, in step (3):

[0030] In the platinum salt solution, the concentration of Pt ions is 0.1-0.2 mol / L;

[0031] The platinum salt includes tetraammineplatinum dihydroxycarbonate dihydrate (Pt(NH3)4(OH)2]CO3·2H2O).

[0032] Specifically, in step (3), the temperature of the roasting step is 350-450° C. It should be noted that in the roasting step, the control of the roasting temperature is related to the manganese salt used. If manganese nitrate is used, the roasting temperature can be controlled at 350-400° C., and if manganese acetate is used, the roasting temperature is controlled at 425-450° C.

[0033] Preferably, in step (3), the impregnation step is equal volume impregnation, and the impregnation time is controlled to be 30-45 minutes.

[0034] Specifically, in the carrier, the portion for copper and manganese loading accounts for 1 / 2-2 / 3 of the carrier, and the portion for platinum loading accounts for 1 / 3-1 / 2 of the carrier.

[0035] The present invention also discloses a catalyst for purifying CO from coal chemical tail gas prepared by the method. In the catalyst, the platinum content (calculated as PtO2) is 0.41%-0.61%, the copper content (calculated as CuO) is 1.15%-1.45%, and the manganese content (calculated as MnO2) is 0.95%-1.27%.

[0036] The present invention also discloses a method for using the catalyst, that is, when the catalyst is loaded, the end loaded with copper and manganese faces the reactor inlet, and after the airflow enters the catalyst bed, it contacts the catalyst bed in the order of copper and manganese - platinum - copper and manganese - platinum.

[0037] In the original three-body regenerative catalytic oxidation unit (RCO) of the gas complex of the Second Fertilizer Plant of Sinopec Qilu Branch, each reactor was loaded with 1.15m3 of NHH-124 catalyst from Rihui Company. 3 , the catalyst is stacked vertically in 2 layers.

[0038] The catalyst for CO purification in coal chemical tail gas of the present invention comprises platinum as a main active component, supplemented by a copper-manganese active component. The copper-manganese-based active component utilizes its excellent low-temperature activity, tolerance for sulfides, and ability to remove sulfides, and is combined with a precious metal platinum active component. The catalyst exhibits excellent low-temperature catalytic oxidation activity for CO, completes conversion at a temperature lower than that of imported catalysts, and can tolerate trace sulfur in low-temperature methanol-washed tail gas from the coal chemical industry, thus meeting the technical requirements for the catalytic oxidation of CO in the aforementioned sulfur-containing tail gas. DETAILED DESCRIPTION

[0039] In the following embodiments of the present invention, the catalyst can be prepared using conventional equipment, or the equipment described in "An Impregnation Catalyst Preparation Equipment and Its Application" previously studied by the applicant can be used to prepare the catalyst.

[0040] Example 1

[0041] Weigh 938 g of aluminum nitrate nonahydrate (analytical grade), dissolve it in water, and prepare a 1 L solution for later use.

[0042] Weigh 221.66 g of copper nitrate hexahydrate and 156.70 g of manganese acetate tetrahydrate, dissolve them in water, and prepare a 1 L solution (copper to manganese ion ratio of 1:1) for later use.

[0043] Weigh 54.795 g of Pt(NH3)4(OH)2]CO3·2H2O, dissolve it in water, and prepare a 1 L solution for later use.

[0044] Select a piece with the specifications of 150mm*150mm*50mm, bulk density of 0.75kg / L, pore density of 200, and specific surface area of ​​1.7m 3 / g, pore volume 22cm 3 / g cordierite carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings, and then set aside.

[0045] The preparation method of the catalyst described in this embodiment comprises the following steps:

[0046] (1) The treated support was placed on a conventional impregnation device, and dust in the pores was blown away with instrument air. The support was then impregnated with the aluminum nitrate solution for 30 minutes. The support was then blown away with instrument air again to remove the residual aluminum nitrate solution in the pores. The support was then dried in an oven at 130°C for 120 minutes, and then calcined at 600°C for 120 minutes.

[0047] (2) The calcined support is placed on the impregnation equipment again, and the control program is set to insert the impregnation nozzle into 2 / 3 of the hole channel to perform copper and manganese impregnation. The impregnation time is controlled to be 90 minutes. After impregnation, the residual solution in the hole channel is purged; the support is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings;

[0048] (3) The semi-finished product obtained after the above-mentioned copper-manganese impregnation and roasting is turned over and placed on the impregnation equipment. The control program sets the impregnation nozzle to be inserted into 1 / 3 of the hole channel for impregnation with the platinum salt solution (the platinum salt solution is added at a rate of 20 mL / 100 g of the carrier). The unabsorbed impregnation liquid returns to the Pt solution intermediate storage tank and is sprayed on the semi-finished product again; the impregnation time is controlled to be 30 minutes. After impregnation, the residual liquid in the hole channel is purged; the semi-finished product is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings; the dried semi-finished product is stacked on the crawler of the tunnel kiln and roasted at a temperature of 450°C for 120 minutes to obtain a finished catalyst.

[0049] After analysis and determination, the platinum content (calculated as PtO2) on the finished catalyst was 0.41%, the copper content (calculated as CuO) was 1.15%, and the manganese content (calculated as MnO2) was 1.26%.

[0050] Example 2

[0051] Weigh 938 g of aluminum nitrate nonahydrate (analytical grade), dissolve it in water, and prepare a 1 L solution for later use.

[0052] Weigh 277.07 g of copper nitrate hexahydrate and 117.52 g of manganese acetate tetrahydrate, dissolve them in water, and prepare a 1 L solution (copper to manganese ion ratio of 1:0.6) for later use.

[0053] Weigh 81.81 g of Pt(NH3)4(OH)2]CO3·2H2O, dissolve it in water, and prepare a 1 L solution for later use.

[0054] Select a piece with the specifications of 150mm*150mm*50mm, bulk density of 0.75kg / L, pore density of 200, and specific surface area of ​​1.7m 3 / g, pore volume 22cm 3 / g cordierite carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings, and then set aside.

[0055] The preparation method of the catalyst described in this embodiment comprises the following steps:

[0056] (1) The carrier is placed on an impregnation device, dust in its pores is blown away with instrument air, and then the carrier is impregnated with the aluminum nitrate solution for 30 minutes. The carrier is again blown away with instrument air to remove the residual aluminum nitrate solution in the pores; the carrier is dried in an oven at 130°C for 120 minutes, and then calcined at 600°C for 120 minutes;

[0057] (2) The calcined support is placed on the impregnation equipment again, and the control program is set to insert the impregnation nozzle into the 2 / 3 of the hole channel to perform copper and manganese impregnation. The impregnation time is controlled to be 90 minutes. After impregnation, the residual solution in the hole channel is purged; the support is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings;

[0058] (3) The semi-finished product obtained after the above-mentioned copper-manganese impregnation and roasting is turned over and placed on the impregnation equipment. The control program sets the impregnation nozzle to be inserted into 1 / 3 of the hole channel for impregnation with the platinum salt solution (the platinum salt solution is added at a rate of 20 mL / 100 g of the carrier). The impregnation liquid that is not absorbed returns to the Pt solution intermediate storage tank and is sprayed on the semi-finished product again; the impregnation time is controlled to be 30 minutes. After impregnation, the residual liquid in the hole channel is purged; the semi-finished product is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings; the dried semi-finished product is stacked on the crawler of the tunnel kiln and roasted at a temperature of 425°C for 120 minutes to obtain a finished catalyst.

[0059] After analysis and determination, the platinum content (calculated as PtO2) on the finished catalyst was 0.61%, the copper content (calculated as CuO) was 1.45%, and the manganese content (calculated as MnO2) was 0.95%.

[0060] Example 3

[0061] Weigh 938 g of aluminum nitrate nonahydrate (analytical grade), dissolve it in water, and prepare a 1 L solution for later use.

[0062] Weigh 277.07 g of copper nitrate hexahydrate and 117.52 g of manganese acetate tetrahydrate, dissolve them in water, and prepare a 1 L solution (copper to manganese ion ratio of 1:0.6) for later use.

[0063] Weigh 54.795 g of Pt(NH3)4(OH)2]CO3·2H2O, dissolve it in water, and prepare a 1 L solution for later use.

[0064] Select a piece with the specifications of 150mm*150mm*50mm, bulk density of 0.75kg / L, pore density of 200, and specific surface area of ​​1.7m 3 / g, pore volume 22cm 3 / g cordierite carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings, and then set aside.

[0065] The preparation method of the catalyst described in this embodiment comprises the following steps:

[0066] (1) The carrier is placed on an impregnation device, dust in its pores is blown away with instrument air, and then the carrier is impregnated with the aluminum nitrate solution for 30 minutes. The carrier is again blown away with instrument air to remove the residual aluminum nitrate solution in the pores; the carrier is dried in an oven at 130°C for 120 minutes, and then calcined at 600°C for 120 minutes;

[0067] (2) The calcined support is placed on the impregnation equipment again, and the control program is set to insert the impregnation nozzle into 2 / 3 of the hole channel to perform copper and manganese impregnation. The impregnation time is controlled to be 90 minutes. After impregnation, the residual solution in the hole channel is purged; the support is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings;

[0068] (3) The semi-finished product obtained after the copper-manganese impregnation and roasting is turned over and placed on the impregnation equipment. The control program sets the impregnation nozzle to be inserted into 1 / 3 of the hole channel for impregnation with the platinum salt solution (the platinum salt solution is added at a rate of 20 mL / 100 g of the carrier). The impregnation liquid that is not absorbed returns to the Pt solution intermediate storage tank and is sprayed on the semi-finished product again; the impregnation time is controlled to be 30 minutes. After impregnation, the residual liquid in the hole channel is purged; the semi-finished product is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings; the dried semi-finished product is stacked on the crawler of the tunnel kiln and roasted at a temperature of 425°C for 120 minutes to obtain a finished catalyst.

[0069] After analysis and determination, the platinum content (calculated as PtO2) on the finished catalyst was 0.41%, the copper content (calculated as CuO) was 1.45%, and the manganese content (calculated as MnO2) was 0.95%.

[0070] Example 4

[0071] Weigh 938 g of aluminum nitrate nonahydrate (analytical grade), dissolve it in water, and prepare a 1 L solution for later use.

[0072] Weigh 221.66 g of copper nitrate hexahydrate and 156.70 g of manganese acetate tetrahydrate, dissolve them in water, and prepare a 1 L solution (copper to manganese ion ratio of 1:1) for later use.

[0073] Weigh 81.81 g of Pt(NH3)4(OH)2]CO3·2H2O, dissolve it in water, and prepare a 1 L solution for later use.

[0074] Select a piece with the specifications of 150mm*150mm*50mm, bulk density of 0.75kg / L, pore density of 200, and specific surface area of ​​1.7m 3 / g, pore volume 22cm 3 / g cordierite carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings, and then set aside.

[0075] The preparation method of the catalyst described in this embodiment comprises the following steps:

[0076] (1) The carrier is placed on an impregnation device, dust in its pores is blown away with instrument air, and then the carrier is impregnated with the aluminum nitrate solution for 30 minutes. The carrier is again blown away with instrument air to remove the residual aluminum nitrate solution in the pores; the carrier is dried in an oven at 130°C for 120 minutes, and then calcined at 600°C for 120 minutes;

[0077] (2) The calcined support is placed on the impregnation equipment again, and the control program is set to insert the impregnation nozzle into 2 / 3 of the hole channel to perform copper and manganese impregnation. The impregnation time is controlled to be 90 minutes. After impregnation, the residual solution in the hole channel is purged; the support is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings;

[0078] (3) The semi-finished product obtained after the copper-manganese impregnation and roasting is turned over and placed on the impregnation equipment. The control program sets the impregnation nozzle to be inserted into 1 / 3 of the hole channel for impregnation with the platinum salt solution (the platinum salt solution is added at a rate of 20 mL / 100 g of the carrier). The impregnation liquid that is not absorbed returns to the Pt solution intermediate storage tank and is sprayed on the semi-finished product again; the impregnation time is controlled to be 30 minutes. After impregnation, the residual liquid in the hole channel is purged; the semi-finished product is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings; the dried semi-finished product is stacked on the crawler of the tunnel kiln and roasted at a temperature of 450°C for 120 minutes to obtain a finished catalyst.

[0079] After analysis and determination, the platinum content (calculated as PtO2) on the finished catalyst was 0.61%, the copper content (calculated as CuO) was 1.15%, and the manganese content (calculated as MnO2) was 1.26%.

[0080] Example 5

[0081] Weigh 938 g of aluminum nitrate nonahydrate (analytical grade), dissolve it in water, and prepare a 1 L solution for later use.

[0082] Weigh 277.07 g of copper nitrate hexahydrate and 161.46 g of manganese nitrate hexahydrate, dissolve them in water, and prepare a 1 L solution (copper to manganese ion ratio of 1:0.6) for later use.

[0083] Weigh 54.795 g of Pt(NH3)4(OH)2]CO3·2H2O, dissolve it in water, and prepare a 1 L solution for later use.

[0084] Select a piece with the specifications of 150mm*150mm*50mm, bulk density of 0.75kg / L, pore density of 200, and specific surface area of ​​1.7m 3 / g, pore volume 22cm 3 / g cordierite carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings, and then set aside.

[0085] The preparation method of the catalyst described in this embodiment comprises the following steps:

[0086] (1) The carrier was placed on an impregnation device, and dust in its pores was blown away with instrument air. The carrier was then impregnated with the aluminum nitrate solution for 30 minutes. The carrier was then blown away with instrument air again to remove the residual aluminum nitrate solution in the pores. The carrier was then dried in an oven at 130°C for 120 minutes, and then calcined at 600°C for 120 minutes.

[0087] (2) The calcined support is placed on the impregnation equipment again, and the control program is set to insert the impregnation nozzle into 2 / 3 of the hole channel to perform copper and manganese impregnation. The impregnation time is controlled to be 90 minutes. After impregnation, the residual solution in the hole channel is purged; the support is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings;

[0088] (3) The semi-finished product obtained after the copper-manganese impregnation and roasting is turned over and placed on the impregnation equipment. The control program sets the impregnation nozzle to be inserted into 1 / 3 of the hole channel for impregnation with the platinum salt solution (the platinum salt solution is added at a rate of 20 mL / 100 g of the carrier). The impregnation liquid that is not absorbed returns to the Pt solution intermediate storage tank and is sprayed on the semi-finished product again; the impregnation time is controlled to be 30 minutes. After impregnation, the residual liquid in the hole channel is purged; the semi-finished product is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until it reaches a constant weight after two consecutive weighings; the dried semi-finished product is stacked on the crawler of the tunnel kiln and roasted at a temperature of 400°C for 120 minutes to obtain a finished catalyst.

[0089] After analysis and determination, the platinum content (calculated as PtO2) on the finished catalyst was 0.41%, the copper content (calculated as CuO) was 1.45%, and the manganese content (calculated as MnO2) was 0.95%.

[0090] Example 6

[0091] Weigh 938 g of aluminum nitrate nonahydrate (analytical grade), dissolve it in water, and prepare a 1 L solution for later use.

[0092] Weigh 221.66 g of copper nitrate hexahydrate and 215.28 g of manganese nitrate hexahydrate, dissolve them in water, and prepare a 1 L solution (copper to manganese ion ratio of 1:1) for later use.

[0093] Weigh 81.81 g of Pt(NH3)4(OH)2]CO3·2H2O, dissolve it in water, and prepare a 1 L solution for later use.

[0094] Select a piece with the specifications of 150mm*150mm*50mm, bulk density of 0.75kg / L, pore density of 200, and specific surface area of ​​1.7m 3 / g, pore volume 22cm 3 / g cordierite carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings, and then set aside.

[0095] The preparation method of the catalyst described in this embodiment comprises the following steps:

[0096] (1) The carrier was placed on an impregnation device, and dust in its pores was blown away with instrument air. The carrier was then impregnated with the aluminum nitrate solution for 30 minutes. The carrier was then blown away with instrument air again to remove the residual aluminum nitrate solution in the pores. The carrier was then dried in an oven at 130°C for 120 minutes, and then calcined at 600°C for 120 minutes.

[0097] (2) The calcined support is placed on the impregnation equipment again, and the control program is set to insert the impregnation nozzle into 2 / 3 of the hole channel to perform copper and manganese impregnation. The impregnation time is controlled to be 90 minutes. After impregnation, the residual solution in the hole channel is purged; the support is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings;

[0098] (3) The semi-finished product obtained after the copper-manganese impregnation and roasting is turned over and placed on the impregnation equipment. The control program sets the impregnation nozzle to be inserted into 1 / 3 of the hole channel for impregnation with the platinum salt solution (the platinum salt solution is added at a rate of 20 mL / 100 g of the carrier). The impregnation liquid that is not absorbed returns to the Pt solution intermediate storage tank and is sprayed on the semi-finished product again; the impregnation time is controlled to be 30 minutes. After impregnation, the residual liquid in the hole channel is purged; the semi-finished product is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings; the dried semi-finished product is stacked on the crawler of the tunnel kiln and roasted at a temperature of 350°C for 120 minutes to obtain a finished catalyst.

[0099] After analysis and determination, the platinum content (calculated as PtO2) on the finished catalyst was 0.61%, the copper content (calculated as CuO) was 1.15%, and the manganese content (calculated as MnO2) was 1.26%.

[0100] Example 7

[0101] Weigh 938 g of aluminum nitrate nonahydrate (analytical grade), dissolve it in water, and prepare a 1 L solution for later use.

[0102] Weigh 221.66 g of copper nitrate hexahydrate and 215.28 g of manganese nitrate hexahydrate, dissolve them in water, and prepare a 1 L solution (copper to manganese ion ratio of 1:1) for later use.

[0103] Weigh 90.04 g of Pt(NH3)4(OH)2]CO3·2H2O, dissolve it in water, and prepare a 1 L solution for later use.

[0104] Select a piece with the specifications of 150mm*150mm*50mm, bulk density of 0.75kg / L, pore density of 200, and specific surface area of ​​1.7m 3 / g, pore volume 22cm 3 / g cordierite carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings, and then set aside.

[0105] The preparation method of the catalyst described in this embodiment comprises the following steps:

[0106] (1) The carrier was placed on an impregnation device, and dust in its pores was blown away with instrument air. The carrier was then impregnated with the aluminum nitrate solution for 30 minutes. The carrier was then blown away with instrument air again to remove the residual aluminum nitrate solution in the pores. The carrier was then dried in an oven at 130°C for 120 minutes, and then calcined at 600°C for 120 minutes.

[0107] (2) The calcined support is placed on the impregnation equipment again, and the control program is set to insert the impregnation nozzle into the 1 / 2 of the hole channel to perform copper and manganese impregnation. The impregnation time is controlled to be 90 minutes. After impregnation, the residual solution in the hole channel is purged; the support is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings;

[0108] (3) The semi-finished product obtained after the copper-manganese impregnation and roasting is turned over and placed on the impregnation equipment. The control program sets the impregnation nozzle to be inserted into 1 / 2 of the hole channel for impregnation with the platinum salt solution (the platinum salt solution is added at a rate of 20 mL / 100 g of the carrier). The impregnation liquid that is not absorbed returns to the Pt solution intermediate storage tank and is sprayed on the semi-finished product again; the impregnation time is controlled to be 30 minutes. After impregnation, the residual liquid in the hole channel is purged; the semi-finished product is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until it reaches a constant weight after two consecutive weighings; the dried semi-finished product is stacked on the crawler of the tunnel kiln and roasted at a temperature of 400°C for 120 minutes to obtain a finished catalyst.

[0109] After analysis and determination, the platinum content (calculated as PtO2) on the finished catalyst was 0.50%, the copper content (calculated as CuO) was 1.15%, and the manganese content (calculated as MnO2) was 1.26%.

[0110] Example 8

[0111] Weigh 938 g of aluminum nitrate nonahydrate (analytical grade), dissolve it in water, and prepare a 1 L solution for later use.

[0112] Weigh 177.32 g of copper nitrate hexahydrate and 172.22 g of manganese nitrate hexahydrate, dissolve them in water, and prepare a 1 L solution (copper to manganese ion ratio of 1:1) for later use.

[0113] Weigh 56.265 g of Pt(NH3)4(OH)2]CO3·2H2O, dissolve it in water, and prepare a 1 L solution for later use.

[0114] Select a piece with the specifications of 150mm*150mm*50mm, bulk density of 0.60kg / L, pore density of 200, and specific surface area of ​​2m 3 / g, pore volume 25cm 3 / g cordierite carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings, and then set aside.

[0115] The preparation method of the catalyst described in this embodiment comprises the following steps:

[0116] (1) The carrier was placed on an impregnation device, and dust in its pores was blown away with instrument air. The carrier was then impregnated with the aluminum nitrate solution for 30 minutes. The carrier was then blown away with instrument air again to remove the residual aluminum nitrate solution in the pores. The carrier was then dried in an oven at 130°C for 120 minutes, and then calcined at 600°C for 120 minutes.

[0117] (2) The calcined support is placed on the impregnation equipment again, and the control program is set to insert the impregnation nozzle into 2 / 3 of the hole channel to perform copper and manganese impregnation. The impregnation time is controlled to be 90 minutes. After impregnation, the residual solution in the hole channel is purged; the support is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings;

[0118] (3) The semi-finished product obtained after the copper-manganese impregnation and roasting is turned over and placed on the impregnation equipment. The control program sets the impregnation nozzle to be inserted into 1 / 3 of the hole channel for impregnation with the platinum salt solution (the platinum salt solution is added at a rate of 24 mL / 100 g of the carrier). The impregnation liquid that is not absorbed returns to the Pt solution intermediate storage tank and is sprayed on the semi-finished product again; the impregnation time is controlled to be 30 minutes. After impregnation, the residual liquid in the hole channel is purged; the semi-finished product is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings; the dried semi-finished product is stacked on the crawler of the tunnel kiln and roasted at a temperature of 380°C for 120 minutes to obtain a finished catalyst.

[0119] After analysis and determination, the platinum content (calculated as PtO2) on the finished catalyst was 0.50%, the copper content (calculated as CuO) was 1.11%, and the manganese content (calculated as MnO2) was 1.21%.

[0120] Comparative Example 1

[0121] XRF analysis of the NHH-124 catalyst produced by Rihui Company showed that the platinum content of the catalyst (calculated as PtO2) was 0.50%. A trial production was carried out according to the preparation method of the present invention, except that the copper-manganese impregnation was not performed.

[0122] Weigh 938 g of aluminum nitrate nonahydrate (analytical grade), dissolve it in water, and prepare a 1 L solution for later use.

[0123] Weigh 42.05 g of Pt(NH3)4(OH)2]CO3·2H2O, dissolve it in water, and prepare a 1 L solution for later use.

[0124] Select a piece with the specifications of 150mm*150mm*50mm, bulk density of 0.75kg / L, pore density of 200, and specific surface area of ​​1.7m 3 / g, pore volume 22cm 3 / g cordierite carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings, and then set aside.

[0125] The preparation method of the catalyst described in this comparative example comprises the following steps:

[0126] (1) The carrier was placed on an impregnation device, and dust in its pores was blown away with instrument air. The carrier was then impregnated with the aluminum nitrate solution for 30 minutes. The carrier was then blown away with instrument air again to remove the residual aluminum nitrate solution in the pores. The carrier was then dried in an oven at 130°C for 120 minutes, and then calcined at 600°C for 120 minutes.

[0127] (2) The calcined carrier is placed on the impregnation equipment again, and the control program is set to insert the impregnation nozzle into the entrance of the hole channel to perform impregnation with the platinum salt solution (21 mL / 100 g carrier is put into the platinum salt solution). The unabsorbed impregnation liquid returns to the Pt solution intermediate storage tank and is sprayed on the semi-finished product again; the impregnation time is controlled to be 30 minutes. After impregnation, the residual liquid in the hole channel is purged; the carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings; the dried semi-finished product is stacked on the crawler of the tunnel kiln and calcined at a temperature of 450°C for 120 minutes to obtain a finished catalyst.

[0128] The analysis showed that the platinum content (calculated as PtO2) on the finished catalyst was 0.50%.

[0129] Comparative Example 2

[0130] The catalyst described in this comparative example is only used to prepare copper-manganese-based catalysts for comparison.

[0131] Weigh 938 g of aluminum nitrate nonahydrate (analytical grade), dissolve it in water, and prepare a 1 L solution for later use.

[0132] Weigh 264.14 g of copper nitrate hexahydrate and 153.92 g of manganese acetate tetrahydrate, dissolve them in water, and prepare a 1 L solution (copper to manganese ion ratio of 1:0.6) for later use.

[0133] Select a piece with the specifications of 150mm*150mm*50mm, bulk density of 0.75kg / L, pore density of 200, and specific surface area of ​​1.7m 3 / g, pore volume 22cm 3 / g cordierite carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings, and then set aside.

[0134] The preparation method of the catalyst described in this comparative example comprises the following steps:

[0135] (1) The carrier was placed on an impregnation device, and dust in its pores was blown away with instrument air. The carrier was then impregnated with the aluminum nitrate solution for 30 minutes. The carrier was then blown away with instrument air again to remove the residual aluminum nitrate solution in the pores. The carrier was then dried in an oven at 130°C for 120 minutes, and then calcined at 600°C for 120 minutes.

[0136] (2) The calcined carrier is placed on the impregnation equipment again. The control program sets the impregnation nozzle to be inserted into the entrance of the hole channel to carry out copper and manganese impregnation. The impregnation time is controlled to be 90 minutes. After impregnation, the residual solution in the hole channel is blown away. Dry in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, weigh it every 30 minutes until the weight is constant after two consecutive weighings. The dried semi-finished product is stacked on the crawler of the tunnel kiln and calcined at a temperature of 400°C for 120 minutes to obtain the finished catalyst.

[0137] The analysis showed that the copper content (calculated as CuO) in the finished catalyst was 1.45%, and the manganese content (calculated as MnO2) was 0.95%.

[0138] Comparative Example 3

[0139] The catalyst described in this comparative example is only used to prepare a catalyst having another copper-manganese ratio for comparison.

[0140] Weigh 938 g of aluminum nitrate nonahydrate (analytical grade), dissolve it in water, and prepare a 1 L solution for later use.

[0141] Weigh 209.84 g of copper nitrate hexahydrate and 203.80 g of manganese acetate tetrahydrate, dissolve them in water, and prepare a 1 L solution (copper to manganese ion ratio of 1:1) for later use.

[0142] Select a piece with the specifications of 150mm*150mm*50mm, bulk density of 0.75kg / L, pore density of 200, and specific surface area of ​​1.7m 3 / g, pore volume 22cm 3 / g cordierite carrier is dried in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, it is weighed every 30 minutes until a constant weight is obtained after two consecutive weighings, and then set aside.

[0143] The preparation method of the catalyst described in this comparative example comprises the following steps:

[0144] (1) The carrier was placed on an impregnation device, and dust in its pores was blown away with instrument air. The carrier was then impregnated with the aluminum nitrate solution for 30 minutes. The carrier was then blown away with instrument air again to remove the residual aluminum nitrate solution in the pores. The carrier was then dried in an oven at 130°C for 120 minutes, and then calcined at 600°C for 120 minutes.

[0145] (2) The calcined carrier is placed on the impregnation equipment again. The control program sets the impregnation nozzle to be inserted into the entrance of the hole channel to carry out copper and manganese impregnation. The impregnation time is controlled to be 90 minutes. After impregnation, the residual solution in the hole channel is blown away. Dry in an oven at 130°C for 120 minutes or more. After drying for 60 minutes, weigh it every 30 minutes until the weight is constant after two consecutive weighings. The dried semi-finished product is stacked on the crawler of the tunnel kiln and calcined at a temperature of 400°C for 120 minutes to obtain the finished catalyst.

[0146] After analysis and determination, the copper content (calculated as CuO) on the finished catalyst was 1.16%, and the manganese content (calculated as MnO2) was 1.26%.

[0147] Comparative Example 4

[0148] This comparative example uses Rihui Industrial Catalyst NHH-124 as a control.

[0149] Comparative Example 5

[0150] The preparation method of the catalyst in this comparative example is the same as that in Example 4, the only difference is that in step (2), all the supports are loaded with copper and manganese, while in step (3), all the supports are loaded with platinum.

[0151] However, during the entire operation process, a considerable amount of platinum will inevitably interact with copper-manganese oxide, causing the copper oxide grains to grow during the use of the catalyst, which will also affect the platinum and seriously affect the use effect of the catalyst.

[0152] Comparative Example 6

[0153] The preparation method of the catalyst in this comparative example is the same as that in Example 4, the only difference being that in step (2), only a single active component of copper or manganese is loaded.

[0154] However, when a single copper or manganese active component is loaded, not only is the activity of the catalyst relatively low (lower than that of the copper-manganese co-loaded catalyst solution), but a conversion rate of 90% or above can only be achieved at 370°C or higher, while the copper-manganese co-loaded catalyst solution can achieve a conversion rate of 90% or above at about 300-310°C.

[0155] Experimental example

[0156] The activities of the samples of Examples 1-8 and Comparative Examples 1-4 were evaluated respectively. The evaluation device used was the device disclosed in Chinese Patent CN107478732B. Test blocks with a size of 80*80*50 mm were cut from the honeycomb catalyst and tested respectively.

[0157] The composition of the raw gas is shown in Table 1 below, the evaluation conditions are shown in Table 2 below, and the evaluation results are shown in Table 3 below.

[0158] Table 1 Composition of raw gas

[0159] Components Composition, vol% <![CDATA[H2]]> 0.5 <![CDATA[N2]]> 97.5 CO 0.5 <![CDATA[H2S]]> 1.5

[0160] Table 2 Evaluation conditions

[0161] project parameter Raw gas flow 6400L / h Air flow 1280L / h pressure 0.015MPa Inlet temperature 300℃ Judging Criteria After running for 50 hours, take the average value of 51-60 hours as the result

[0162] Table 3 Evaluation results

[0163] serial number Carbon monoxide content of outlet process gas, % Example 1 0.0116 Example 2 0.0098 Example 3 0.0114 Example 4 0.0097 Example 5 0.0113 Example 6 0.0097 Example 7 0.0099 Example 8 0.0101 Comparative Example 1 0.0124 Comparative Example 2 0.0157 Comparative Example 3 0.0171 NHH-124 0.0121

[0164] As can be seen from the data in the above table, the catalyst of the present invention exhibits excellent low-temperature catalytic oxidation activity for CO, completes the conversion at a temperature lower than that of imported agents, can tolerate trace amounts of sulfur in low-temperature methanol-washed tail gas from coal chemical industry, and can meet the technical requirements for the catalytic oxidation of CO in the above-mentioned sulfur-containing tail gas.

[0165] In the comparative example, the catalyst loaded only with copper manganese (without Pt loading) not only causes the reaction temperature to rise, but also reduces the activity and stability of the catalyst. This is mainly because the stability of copper oxide is insufficient at high temperature, and the grains sinter and grow, which affects the effect of the catalyst.

[0166] Therefore, the catalyst prepared by the present invention based on the method of co-loading copper, manganese and platinum elements in different regions not only has good catalytic performance, but also has high catalyst stability. Even when reacting at a high temperature of 500°C, the stability is still very good.

[0167] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst for purifying CO from coal chemical tail gas, characterized in that: The steps include: (1) preparing an aluminum salt solution by preparing a water-soluble aluminum salt, and immersing a monolithic porous support in the aluminum salt solution for aluminum loading, followed by drying and calcining to form an aluminum oxide coating having a large specific surface area; (2) preparing a water-soluble copper-manganese salt to form a copper-manganese salt solution, and partially immersing the carrier treated in step (1) in the copper-manganese salt solution to load copper and manganese, and drying the carrier to form a carrier partially loaded with copper and manganese; (3) taking a water-soluble platinum salt to form a platinum salt solution, and immersing the portion of the support treated in step (2) without copper and manganese loading in the platinum salt solution for platinum loading, drying and calcining to obtain; Wherein, in the carrier, the portion for copper and manganese loading accounts for 1 / 2-2 / 3 of the carrier, and the portion for platinum loading accounts for 1 / 3-1 / 2 of the carrier; The obtained catalyst has a platinum content of 0.41%-0.61%, a copper content of 1.15%-1.45%, and a manganese content of 0.95%-1.27%.

2. The method for preparing a catalyst for purifying CO from coal chemical tail gas according to claim 1, characterized in that: In the step (1), the monolithic porous carrier comprises cordierite honeycomb ceramics.

3. The method for preparing a catalyst for purifying CO from coal chemical tail gas according to claim 1 or 2, characterized in that: In step (1): In the aluminum salt solution, the concentration of Al ions is 2-2.5 mol / L; The aluminum salt includes aluminum nitrate.

4. The method for preparing a catalyst for purifying CO from coal chemical tail gas according to claim 3, characterized in that: In the step (1), the temperature of the calcination step is 500-600°C.

5. The method for preparing a catalyst for purifying CO from coal chemical tail gas according to claim 1, characterized in that: In step (2): In the copper-manganese salt solution, the total concentration of Cu and Mn ions is 1.2-1.5 mol / L; In the copper-manganese salt solution, the concentration ratio of Cu and Mn ions is 1:1-1:0.6; The manganese salt includes manganese nitrate and / or manganese acetate; The copper salt includes copper nitrate and / or copper sulfate.

6. The method for preparing a catalyst for purifying CO from coal chemical tail gas according to claim 1, characterized in that: In step (3): In the platinum salt solution, the concentration of Pt ions is 0.1-0.2 mol / L; The platinum salt includes dihydroxytetraammineplatinum carbonate dihydrate.

7. The method for preparing a catalyst for purifying CO from coal chemical tail gas according to claim 6, characterized in that: In the step (3), the temperature of the calcination step is 350-450°C.

8. A catalyst for purifying CO from coal chemical tail gas prepared by the method according to any one of claims 1 to 7, characterized in that: The catalyst has a platinum content of 0.41%-0.61%, a copper content of 1.15%-1.45%, and a manganese content of 0.95%-1.27%.

9. The method for using the catalyst according to claim 8, characterized in that: When the catalyst is loaded, the end loaded with copper and manganese faces the reactor inlet. After the airflow enters the catalyst bed, it contacts the catalyst bed in the order of copper and manganese - platinum - copper and manganese - platinum.