Preparation method of carbon monoxide synergistic denitrification powder catalyst

Abstract

The present invention belongs to the field of catalytic technology, and specifically relates to a method for preparing a powder catalyst for carbon monoxide synergistic denitration. The method comprises the following steps: uniformly mixing cobalt salt, copper salt, template agent and pure water to obtain a precursor solution, spray drying to obtain a spray material, and then calcining to obtain a calcined material, mixing the calcined material, vanadium salt and water and performing a hydrothermal reaction to obtain a slurry, and calcining to obtain a powder; and screening to obtain a powder catalyst for carbon monoxide synergistic denitration. The present invention reduces the overall preparation time of the catalyst, reduces the preparation steps of the carrier, and innovatively uses a template agent and sprays and calcines to directly prepare copper-cobalt microspheres with a copper-cobalt ion composite structure. The copper-cobalt microspheres can serve as both a carrier and an active component, synergizing with vanadium oxide to improve the denitration efficiency and decarbonization efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysis, and in particular relates to a method for preparing a carbon monoxide synergistic denitration powder catalyst. Background Art

[0002] With the continuous deepening of air pollution prevention and control work in my country, nitrogen oxides NO X CO and CO have been effectively controlled, and environmental quality has improved. As a major atmospheric pollutant, CO is very easy to combine with hemoglobin, which carries oxygen in the blood. At low concentrations, it can cause hypoxia damage to humans or animals. Therefore, reducing CO emissions is receiving increasing attention from governments and companies. The sintering flue gas in the steel industry is CO and NO. X The main source of CO and NO X Emissions are crucial to continuously improving the quality of the atmospheric environment.

[0003] Chinese patent CN114160152A discloses a dual-action denitrification and decarbonization catalyst and its preparation method. The catalyst comprises copper-cobalt composite oxide and vanadium (V2O5) as active components, with TiO2 as a carrier. Based on the mass of the carrier, the mass percentage of the copper-cobalt composite oxide active component is 6.65% to 11.12%, and the mass percentage of the vanadium (V2O5) active component is 0.65% to 1.94%. The molar ratio of Cu to Co in the copper-cobalt composite oxide active component is 1:(0.64-1.64). This patent uses TiO2 as a carrier, copper-cobalt composite oxide, and vanadium (V2O5) as active components. The addition of the TiO2 carrier requires a long preparation time, reduces the active component content, and ultimately fails to achieve high denitrification and decarbonization efficiencies.

[0004] Chinese patent CN114160186A discloses a catalyst for the simultaneous removal of nitrogen oxides and carbon monoxide, as well as its preparation method and application. The invention relates to a catalyst for the simultaneous removal of nitrogen oxides and carbon monoxide, as well as its preparation method and application. The catalyst utilizes an acid-modified microporous or mesoporous material as a support, which is loaded with an active component; the active component comprises any one or a combination of at least two oxides of copper, manganese, vanadium, cerium, niobium, cobalt, or iron. The catalyst exhibits high medium-temperature SCR denitrification and CO removal activity within the temperature range of 150-300°C, with denitrification and CO removal efficiencies exceeding 90%. The catalyst system components are environmentally friendly and suitable for most NH3-SCR systems, requiring no reductant replacement and unrestricted by oxygen-deficient flue gas conditions. The catalyst has a simple preparation process and low cost, making it suitable for the simultaneous removal of NOx and CO from most industrial flue gases. The patent utilizes an acid-modified microporous or mesoporous material as a support, which takes a long time to prepare and reduces the active component content, resulting in lower denitrification and decarbonization efficiencies.

[0005] There is an urgent need for a method to remove CO and NO in sintering flue gas. X The powder catalyst for highly efficient carbon monoxide treatment is used to coordinate denitrification and improve both denitrification and decarbonization efficiencies. Summary of the Invention

[0006] The present invention provides a method for preparing a carbon monoxide synergistic denitration powder catalyst. The prepared catalyst has a high content of active components and a good carbon monoxide synergistic denitration effect.

[0007] The method for preparing the carbon monoxide synergistic denitrification powder catalyst of the present invention comprises the following steps:

[0008] (1) Prepare the precursor solution: mix the cobalt salt, copper salt, template and pure water to obtain a precursor solution;

[0009] (2) Spray drying: spray drying the precursor solution to obtain a spray material;

[0010] (3) Calcination: Calcination of the sprayed material to obtain a calcined material;

[0011] (4) Hydrothermal reaction: the calcined material, vanadium salt and water are mixed and subjected to hydrothermal reaction to obtain a slurry;

[0012] (5) Calcination: Calcinate the slurry to obtain powder;

[0013] (6) Screening: Use a sample sieve to screen the powder to obtain a carbon monoxide synergistic denitrification powder catalyst.

[0014] in:

[0015] In step (1), the cobalt salt is one or more of cobalt nitrate or cobalt chloride; the copper salt is one or more of copper nitrate or copper chloride; and the template agent is one or more of tryptophan, glutamic acid or glycine.

[0016] In step (1), the mass ratio of cobalt salt, copper salt, template agent and pure water is (160-300): (600-800): (10-12): 1000.

[0017] In step (2), the spray drying temperature is 95-100°C, and the spray material D50 is 50-100 μm.

[0018] In step (3), the calcination temperature is 400-450°C and the calcination time is 2-4 h.

[0019] In step (3), the calcined material is copper-cobalt microspheres.

[0020] In step (4), the mass ratio of the roasting material, the vanadium salt and the water is 1000:(30-45):1200.

[0021] In step (4), the vanadium salt is ammonium metavanadate.

[0022] In step (4), the hydrothermal reaction temperature is 105-125° C., the hydrothermal reaction pressure is 0.1-0.4 MPa, and the hydrothermal reaction time is 2-6 h.

[0023] In step (5), the calcination temperature is 400-500°C and the calcination time is 2-6 h.

[0024] In step (6), the particle size of the carbon monoxide collaborative denitrification powder catalyst is 10-40 mesh.

[0025] The beneficial effects of the present invention are as follows:

[0026] The precursor solution of the present invention is sprayed and calcined to form copper-cobalt microspheres with a copper-cobalt ion composite structure, which has a pore structure and increases the specific surface area. After hydrothermal treatment, vanadium oxide is in situ loaded on the surface of the copper-cobalt microspheres to form a carbon monoxide synergistic denitrification powder catalyst, which has a high efficiency in the removal of CO and NO. X Performs dual adsorption and redox.

[0027] The present invention innovatively prepares copper-cobalt microspheres with a copper-cobalt ion composite structure, replacing conventional catalyst supports to load vanadium oxide. This reduces the overall catalyst preparation time and the number of steps required to prepare the support. The innovative use of a template, followed by spraying and calcination, directly produces copper-cobalt microspheres with a copper-cobalt ion composite structure. The copper-cobalt microspheres serve as both a support and an active component, synergizing with vanadium oxide.

[0028] The catalyst of the present invention has the advantages of high activity, large specific surface area and wide window range, thereby improving the denitrification efficiency and decarbonization efficiency. The present invention is simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a SEM image of the copper-cobalt microspheres of Example 1 of the present invention;

[0030] Figure 2 1-2 is a graph showing the CO removal efficiency of Examples 1-4 and Comparative Examples 1-2 of the present invention;

[0031] Figure 3 It is a graph showing the denitration efficiency data of Examples 1-4 of the present invention and Comparative Examples 1-2. DETAILED DESCRIPTION

[0032] The present invention is described and illustrated in detail below with reference to the embodiments.

[0033] Example 1

[0034] (1) Weigh 160 g of cobalt nitrate and transfer it to a 5 L reactor. Then add 800 g of copper nitrate, 10 g of tryptophan, and 1000 g of pure water in sequence. Stir for 30 minutes until all the above materials are dissolved to obtain a precursor solution.

[0035] (2) spray drying the precursor solution to obtain a spray material; the spray drying temperature is controlled to be 95°C, and the spray material D50 is 50-100 μm;

[0036] (3) After spray drying, the spray material is placed in an electric furnace and calcined at a temperature of 420°C for 4 hours to obtain a calcined material; the calcined material is copper-cobalt microspheres;

[0037] (4) Weigh 1000 g of the calcined material, 35 g of ammonium metavanadate, and 1200 g of pure water, transfer them to a reactor, start stirring, heat to 105°C, and control the pressure in the reactor to 0.1 MPa. The reaction time is 6 h, and a slurry is obtained by hydrothermal reaction.

[0038] (5) calcining the slurry to obtain powder at a temperature of 400°C for 4 hours;

[0039] (6) Screening: Use a sample sieve to screen the powder to obtain a carbon monoxide synergistic denitrification powder catalyst with a particle size of 40 mesh.

[0040] Example 2

[0041] (1) Weigh 300 g of cobalt nitrate and transfer it to a 5 L reactor. Then add 800 g of copper nitrate, 10 g of glutamic acid, and 1000 g of pure water in sequence. Stir for 30 minutes until all the above materials are dissolved to obtain a precursor solution.

[0042] (2) spray drying the precursor solution to obtain a spray material; the spray drying temperature is controlled to be 100°C, and the spray material D50 is 50-100 μm;

[0043] (3) After spray drying, the spray material is placed in an electric furnace and calcined at a temperature of 450°C for 2 hours to obtain a calcined material; the calcined material is copper-cobalt microspheres;

[0044] (4) Weigh 1000 g of the calcined material, 30 g of ammonium metavanadate, and 1200 g of pure water, transfer them to a reactor, start stirring, heat to 110°C, and control the pressure in the reactor to 0.2 MPa. The reaction time is 4 h, and the slurry is obtained by hydrothermal reaction;

[0045] (5) calcining the slurry to obtain powder at a temperature of 500°C and a calcination time of 2 hours;

[0046] (6) Screening: Use a sample sieve to screen the powder to obtain a carbon monoxide synergistic denitrification powder catalyst with a particle size of 20 mesh.

[0047] Example 3

[0048] (1) Weigh 200 g of cobalt chloride and transfer it to a 5 L reactor. Then add 600 g of copper chloride, 5 g of glycine, 6 g of tryptophan, and 1000 g of pure water in sequence. Stir for 30 minutes until all the above materials are dissolved to obtain a precursor solution.

[0049] (2) spray drying the precursor solution to obtain a spray material; the spray drying temperature is controlled to be 100°C, and the spray material D50 is 50-100 μm;

[0050] (3) After spray drying, the spray material is placed in an electric furnace and calcined at a temperature of 400°C for 4 hours to obtain a calcined material; the calcined material is copper-cobalt microspheres;

[0051] (4) Weigh 1000 g of the calcined material, 40 g of ammonium metavanadate, and 1200 g of pure water, transfer them to a reactor, start stirring, heat to 120°C, and control the pressure in the reactor to 0.3 MPa. The reaction time is 3 h, and a slurry is obtained by hydrothermal reaction.

[0052] (5) calcining the slurry to obtain powder at a temperature of 450°C for 6 hours;

[0053] (6) Screening: Use a sample sieve to screen the powder to obtain a carbon monoxide synergistic denitrification powder catalyst with a particle size of 10 mesh.

[0054] Example 4

[0055] (1) Weigh 200 g of cobalt chloride and transfer it to a 5 L reactor. Then add 800 g of copper chloride, 6 g of glutamic acid, 6 g of tryptophan, and 1000 g of pure water in sequence. Stir for 30 minutes until all the above materials are dissolved to obtain a precursor solution.

[0056] (2) spray drying the precursor solution to obtain a spray material; the spray drying temperature is controlled to be 98°C, and the spray material D50 is 50-100 μm;

[0057] (3) After spray drying, the spray material is placed in an electric furnace for calcination at a temperature of 430°C for 3.5 hours to obtain a calcined material; the calcined material is copper-cobalt microspheres;

[0058] (4) Weigh 1000 g of the calcined material, 45 g of ammonium metavanadate, and 1200 g of pure water, transfer them to a reactor, start stirring, heat to 125°C, and control the pressure in the reactor to 0.4 MPa. The reaction time is 2 h, and a slurry is obtained by hydrothermal reaction.

[0059] (5) calcining the slurry to obtain powder at a temperature of 480°C for 3 hours;

[0060] (6) Screening: Use a sample sieve to screen the powder to obtain a carbon monoxide synergistic denitrification powder catalyst with a particle size of 30 mesh.

[0061] Comparative Example 1

[0062] The other steps were the same as in Example 1 except that tryptophan was not added.

[0063] (1) Weigh 160 g of cobalt nitrate and transfer it to a 5 L reactor. Then add 800 g of copper nitrate and 1000 g of pure water in sequence. Stir for 30 minutes until all the above materials are dissolved to obtain a precursor solution.

[0064] (2) spray drying the precursor solution to obtain a spray material; the spray drying temperature is controlled to be 95°C, and the spray material D50 is 50-100 μm;

[0065] (3) After spray drying, the spray material is placed in an electric furnace and calcined at a temperature of 420°C for 4 hours to obtain a calcined material; the calcined material is copper-cobalt microspheres;

[0066] (4) Weigh 1000 g of the calcined material, 35 g of ammonium metavanadate, and 1200 g of pure water, transfer them to a reactor, start stirring, heat to 105°C, and control the pressure in the reactor to 0.1 MPa. The reaction time is 6 h, and a slurry is obtained by hydrothermal reaction.

[0067] (5) calcining the slurry to obtain powder at a temperature of 400°C for 4 hours;

[0068] (6) Screening: Use a sample sieve to screen the powder to obtain a carbon monoxide synergistic denitrification powder catalyst with a particle size of 40 mesh.

[0069] Comparative Example 2

[0070] The remaining steps were the same as in Example 2 except that glutamic acid was not added.

[0071] (1) Weigh 300 g of cobalt nitrate and transfer it to a 5 L reactor. Then add 800 g of copper nitrate and 1000 g of pure water in sequence. Stir for 30 minutes until all the above materials are dissolved to obtain a precursor solution.

[0072] (2) spray drying the precursor solution to obtain a spray material; the spray drying temperature is controlled to be 100°C, and the spray material D50 is 50-100 μm;

[0073] (3) After spray drying, the spray material is placed in an electric furnace and calcined at a temperature of 450°C for 2 hours to obtain a calcined material; the calcined material is copper-cobalt microspheres;

[0074] (4) Weigh 1000 g of the calcined material, 30 g of ammonium metavanadate, and 1200 g of pure water, transfer them to a reactor, start stirring, heat to 110°C, and control the pressure in the reactor to 0.2 MPa. The reaction time is 4 h, and the slurry is obtained by hydrothermal reaction;

[0075] (5) calcining the slurry to obtain powder at a temperature of 500°C and a calcination time of 2 hours;

[0076] (6) Screening: Use a sample sieve to screen the powder to obtain a carbon monoxide synergistic denitrification powder catalyst with a particle size of 20 mesh.

[0077] The data of the catalyst compositions and specific surface areas of Examples 1-4 and Comparative Examples 1-2 are shown in Table 1.

[0078]

[0079] The performance of the carbon monoxide synergistic denitration powder catalysts prepared in Examples 1 to 4 and Comparative Examples 1 to 2 was evaluated. The performance evaluation unit consisted of a gas distribution system, a flue gas heating system, a reactor system, and a flue gas exhaust system connected in sequence.

[0080] 1. Gas distribution system

[0081] The performance evaluation test used standard cylinder gas to simulate flue gas, with N2 generated using a nitrogen generator. The flue gas composition included N2, H2O, O2, NO, SO2, and CO. The gases were metered by a mass flow meter and then fed into a mixer. After mixing, they entered a flue gas preheater.

[0082] Test conditions:

[0083] Flue gas volume composition: N2 approximately 80.2%, H2O approximately 9.8%, O2 approximately 9.9%, NO approximately 300ppm, SO2 approximately 50ppm, CO approximately 1000ppm.

[0084] Total flue gas volume: 1L / min, catalyst loading: 5g.

[0085] 2. Flue gas heating system

[0086] The flue gas heater heats the flue gas to 125°C to ensure that the required temperature conditions are achieved in the reactor. A temperature controller is used to control the temperature of the flue gas at the flue gas preheater outlet with a control accuracy of ±5°C.

[0087] 3. Reactor system

[0088] To prevent flue gas short-circuiting, the catalyst is wrapped with asbestos tape before being placed in the reactor, sealing the gap between the catalyst and the reactor's inner wall. The reactor is electrically heated, with a thermocouple measuring the reactor temperature. A temperature controller controls the reaction temperature with an accuracy of ±5°C.

[0089] 4. Flue gas emission system

[0090] The treated flue gas will be discharged through the flue gas emission system after being tested and found to meet the standards.

[0091] 5. Data processing

[0092] (1) CO removal efficiency

[0093] ;

[0094] Where:

[0095] CO removal efficiency, unit: %

[0096] C1—CO content in the flue gas at the reactor inlet, gaseous volume ratio, dry basis, μl / L;

[0097] C2—CO content in the flue gas at the reactor outlet, gaseous volume ratio, dry basis, μl / L.

[0098] (2) Denitrification efficiency, i.e. NO x The removal rate is calculated as follows:

[0099] ;

[0100] Where:

[0101] Denitrification efficiency, unit: %;

[0102] D1—NO in flue gas at the reactor inletx Content, gas volume ratio, dry basis, mg / Nm 3 ;

[0103] D2—NO in flue gas at reactor outlet x Content, gas volume ratio, dry basis, mg / Nm 3 .

[0104] Experiments have shown that the optimal operating temperature for the catalysts of Examples 1-4 is 320° C. The CO removal efficiency and denitrification efficiency data of the catalysts of Examples 1-4 and Comparative Example 1-2, when operated at 320° C., are shown in Table 2.

[0105]

[0106] Although the present invention has been described in detail with reference to the accompanying drawings and in conjunction with the embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, those skilled in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall fall within the scope of the present invention.

Claims

1. A method for preparing a powder catalyst for removing carbon monoxide and denitrification, characterized in that: The following steps are involved: (1) Prepare the precursor solution: mix the cobalt salt, copper salt, template and pure water to obtain a precursor solution; (2) Spray drying: spray drying the precursor solution to obtain a spray material; (3) Calcination: Calcination of the sprayed material to obtain a calcined material; (4) Hydrothermal reaction: the calcined material, vanadium salt and water are mixed and subjected to hydrothermal reaction to obtain a slurry; (5) Calcination: Calcinate the slurry to obtain powder; (6) Sieving: Use a sample sieve to sieve the powder to obtain a powder catalyst; The template agent is one or more of tryptophan, glutamic acid or glycine; the mass ratio of cobalt salt, copper salt, template agent and pure water is (160-300): (600-800): (10-12): 1000.

2. The method for preparing a powder catalyst for removing carbon monoxide and denitrification according to claim 1, characterized in that: In step (1), the cobalt salt is one or more of cobalt nitrate and cobalt chloride; the copper salt is one or more of copper nitrate and copper chloride.

3. The method for preparing a powder catalyst for removing carbon monoxide and denitrification according to claim 1, characterized in that: In step (2), the spray drying temperature is 95-100°C.

4. The method for preparing a powder catalyst for removing carbon monoxide and denitrification according to claim 1, characterized in that: In step (3), the calcination temperature is 400-450°C and the calcination time is 2-4 h.

5. The method for preparing a powder catalyst for removing carbon monoxide and denitrification according to claim 1, characterized in that: In step (4), the mass ratio of the roasting material, the vanadium salt and the water is 1000:(30-45):1200.

6. The method for preparing a powder catalyst for removing carbon monoxide and denitrification according to claim 1, characterized in that: In step (4), the vanadium salt is ammonium metavanadate.

7. The method for preparing a powder catalyst for removing carbon monoxide and denitrification according to claim 1, characterized in that: In step (4), the hydrothermal reaction temperature is 105-125° C., the hydrothermal reaction pressure is 0.1-0.4 MPa, and the hydrothermal reaction time is 2-6 h.

8. The method for preparing a powder catalyst for removing carbon monoxide and denitrification according to claim 1, characterized in that: In step (5), the calcination temperature is 400-500°C and the calcination time is 2-6 h.

9. The method for preparing a powder catalyst for removing carbon monoxide and denitrification according to claim 1, characterized in that: In step (6), the particle size of the powder catalyst is 10-40 mesh.

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