Temperature-resistant polymer denitration agent and preparation method thereof

Abstract

The invention relates to the technical field of denitration agents, and discloses a temperature-resistant high-molecular denitration agent and a preparation method thereof.The high-molecular denitration agent is prepared from, by weight, 60-75 parts of MOFs-based bimetallic oxide catalyst, 25-40 parts of melamine-urea-formaldehyde resin, 1.5-3 parts of sodium hydroxide and 0.6-1.2 parts of calcium carbonate; the preparation method comprises the following steps: carrying out solvothermal reaction on 3, 3 '-dihydroxy-[1, 1'-biphenyl]-4, 4 '-dicarboxylic acid, a manganese source and a cobalt source to obtain bimetallic MOFs, carrying out high-temperature calcination to obtain a novel MOFs-based bimetallic oxide catalyst, and compounding the novel MOFs-based bimetallic oxide catalyst with melamine-urea-formaldehyde resin as a main agent with sodium hydroxide and calcium carbonate to obtain a denitration catalyst with the NO conversion rate of 88.9-96.5%. The denitration performance is very good.

Description

Technical Field

[0001] The invention relates to the technical field of denitrification agents, in particular to a temperature-resistant polymer denitrification agent and a preparation method thereof. Background Art

[0002] In the process of coal-fired boiler operation and garbage incineration, a large amount of nitrogen monoxide, nitrogen dioxide, sulfur dioxide and other gases will be produced. These gases will cause acid rain, photochemical smog and other pollution problems in the air, which will have a great impact on the environment and human health and safety. The current denitrification processes mainly include polymer non-catalytic reduction method, selective catalytic reduction method, selective non-catalytic reduction method, etc.

[0003] The polymer non-catalytic reduction method decomposes at high temperature to produce active groups such as carbon nitrogen and carbon oxygen, which react with nitrogen monoxide in the flue gas to generate non-polluting substances such as nitrogen and water, achieving efficient denitration. The invention patent with publication number CN115970487A discloses a polymer resin denitrifier and its preparation method. Urea, melamine and formaldehyde are polymerized into an amino polymer resin, and then an alkali metal promoter is added. The obtained polymer resin denitrifier has strong heat resistance and can well improve the denitration performance. Combining the polymer resin denitrifier with an inorganic metal catalyst can further improve the denitration performance. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a high-denitrification-rate temperature-resistant polymer denitrification agent.

[0005] The technical solution provided by the present invention is: a temperature-resistant polymer denitrifying agent, comprising 60-75 parts by weight of MOFs-based bimetallic oxide catalyst, 25-40 parts by weight of melamine-urea-formaldehyde resin, 1.5-3 parts by weight of sodium hydroxide, and 0.6-1.2 parts by weight of calcium carbonate.

[0006] The preparation method of the MOFs-based bimetallic oxide catalyst comprises:

[0007] (1) Add N,N-dimethylformamide, water, ethanol, manganese source, cobalt source, and 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarboxylic acid into a flask, stir, and pour the solution into a hydrothermal reactor. After the reaction, centrifuge, wash with water and ethanol, and dry to obtain bimetallic MOFs.

[0008] (2) placing the bimetallic MOFs in a tubular furnace, heating the furnace to a calcination temperature, performing heat preservation treatment, and cooling the furnace to obtain a MOFs-based bimetallic oxide catalyst.

[0009] Preferably, in (1), the volume ratio of N,N-dimethylformamide, water and ethanol is 100:(12-20):(5-15).

[0010] Preferably, in (1), the molar ratio of the manganese source, the cobalt source, and 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarboxylic acid is (88-95):(5-12):50.

[0011] Preferably, in (1), the manganese source is manganese nitrate or manganese sulfate.

[0012] Preferably, in (1), the cobalt source is cobalt nitrate or cobalt sulfate.

[0013] Preferably, in (1), the reaction temperature is 100-130°C and the reaction time is 12-18h.

[0014] Preferably, in (2), the heating rate is 1-2°C / min, the calcination temperature is 500-600°C, and the holding time is 2-3h.

[0015] Preferably, the preparation method of melamine-urea-formaldehyde resin comprises: adding formaldehyde aqueous solution to a flask equipped with a condenser, adding sodium hydroxide to adjust the pH to 8-8.5, then adding urea, heating to 90-95°C, reacting for 40-60 minutes, adding formic acid to adjust the pH to 4.5-5, adding more urea, reacting for 30-40 minutes, adding sodium hydroxide to adjust the pH to 9-9.5, adding melamine, reacting for 60-90 minutes, cooling the material, drying and removing water, and obtaining melamine-urea-formaldehyde resin.

[0016] Preferably, the molar ratio of formaldehyde, urea and melamine is (4.2-4.8):(0.3-0.4):1.

[0017] Preferably, the preparation method of the heat-resistant polymer denitrifier comprises: adding a MOFs-based bimetallic oxide catalyst, melamine-urea-formaldehyde resin, calcium carbonate, and sodium hydroxide into a mixer, mixing and discharging the materials to obtain a heat-resistant polymer denitrifier.

[0018] The technical effect of the present invention is: the present invention uses 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarboxylic acid, a manganese source and a cobalt source for solvent thermal reaction to obtain bimetallic MOFs, and then obtains a novel MOFs-based bimetallic oxide catalyst through high-temperature calcination.

[0019] The present invention uses MOFs-based bimetallic oxide catalyst and melamine-urea-formaldehyde resin as the main agent of the denitration catalyst, and compound them with sodium hydroxide and calcium carbonate. The NO conversion rate of the obtained denitration catalyst reaches 88.9-96.5%, showing good denitration performance. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present disclosure clearer, the technical solution of the present disclosure will be clearly and completely described in combination with the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be arbitrarily combined with each other without conflict.

[0021] Example 1

[0022] (1) Add 200 mL of N,N-dimethylformamide, 24 mL of water, 10 mL of ethanol, 9.5 mmol of manganese nitrate, 0.5 mmol of cobalt nitrate, and 5 mmol of 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarboxylic acid into a flask, stir, and then pour the solution into a hydrothermal reactor, react at 130°C for 12 h, cool, centrifuge, wash with water, ethanol, and dry to obtain bimetallic MOFs.

[0023] (2) The bimetallic MOFs were placed in a tubular furnace, heated to 500°C at a heating rate of 1°C / min, kept at this temperature for 2 hours, and cooled to obtain a MOFs-based bimetallic oxide catalyst.

[0024] (3) Add 800 mL of an aqueous solution containing 4.5 mol formaldehyde to a flask equipped with a condenser, add sodium hydroxide to adjust the pH to 8, then add 0.12 mol urea, heat to 95° C., react for 40 min, add formic acid to adjust the pH to 4.5, then add 0.28 mol urea, react for 40 min, add sodium hydroxide to adjust the pH to 9.5, add 0.1 mol melamine, react for 60 min, cool the material, dry and remove water to obtain melamine-urea-formaldehyde resin.

[0025] (4) Add 60 g of MOFs-based bimetallic oxide catalyst, 40 g of melamine-urea-formaldehyde resin, 0.8 g of calcium carbonate, and 2.2 g of sodium hydroxide into a mixer, mix and discharge, and obtain a temperature-resistant polymer denitrification agent.

[0026] Example 2

[0027] (1) Add 200 mL of N,N-dimethylformamide, 40 mL of water, 30 mL of ethanol, 9.2 mmol of manganese nitrate, 0.8 mmol of cobalt nitrate, and 5 mmol of 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarboxylic acid into a flask, stir, and then pour the solution into a hydrothermal reactor, react at 120°C for 12 h, cool, centrifuge, wash with water, ethanol, and dry to obtain bimetallic MOFs.

[0028] (2) The bimetallic MOFs were placed in a tubular furnace, heated to 600°C at a heating rate of 1°C / min, kept at this temperature for 3 hours, and cooled to obtain a MOFs-based bimetallic oxide catalyst.

[0029] (3) Add 600 mL of an aqueous solution containing 4.8 mol formaldehyde to a flask equipped with a condenser, add sodium hydroxide to adjust the pH to 8.5, then add 0.1 mol urea, heat to 90°C, react for 60 min, add formic acid to adjust the pH to 5, then add 0.25 mol urea, react for 40 min, add sodium hydroxide to adjust the pH to 9.5, add 0.1 mol melamine, react for 60 min, cool the material, dry and remove water to obtain melamine-urea-formaldehyde resin.

[0030] (4) Add 75 g of MOFs-based bimetallic oxide catalyst, 25 g of melamine-urea-formaldehyde resin, 0.6 g of calcium carbonate, and 3 g of sodium hydroxide into a mixer, mix and discharge, and obtain a temperature-resistant polymer denitrification agent.

[0031] Example 3

[0032] (1) Add 200 mL of N,N-dimethylformamide, 24 mL of water, 10 mL of ethanol, 8.8 mmol of manganese sulfate, 1.2 mmol of cobalt sulfate, and 5 mmol of 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarboxylic acid into a flask, stir, and then pour the solution into a hydrothermal reactor, react at 100°C for 18 h, cool, centrifuge, wash with water, ethanol, and dry to obtain bimetallic MOFs.

[0033] (2) The bimetallic MOFs were placed in a tubular furnace, heated to 600°C at a heating rate of 2°C / min, kept at this temperature for 2 hours, and cooled to obtain a MOFs-based bimetallic oxide catalyst.

[0034] (3) Add 600 mL of an aqueous solution containing 4.2 mol formaldehyde to a flask equipped with a condenser, add sodium hydroxide to adjust the pH to 8, then add 0.1 mol urea, heat to 90°C, react for 40 min, add formic acid to adjust the pH to 5, then add 0.2 mol urea, react for 30 min, add sodium hydroxide to adjust the pH to 9, add 0.1 mol melamine, react for 90 min, cool the material, dry and remove water to obtain melamine-urea-formaldehyde resin.

[0035] (4) Add 67 g of MOFs-based bimetallic oxide catalyst, 33 g of melamine-urea-formaldehyde resin, 1.2 g of calcium carbonate, and 1.5 g of sodium hydroxide into a mixer, mix and discharge the materials to obtain a temperature-resistant polymer denitrification agent.

[0036] Comparative Example 1

[0037] The difference between this comparative example and Example 1 is that no MOFs-based bimetallic oxide catalyst is added.

[0038] (1) Add 40 g of melamine-urea-formaldehyde resin, 0.8 g of calcium carbonate, and 2.2 g of sodium hydroxide into a mixer, mix and discharge the materials to obtain a temperature-resistant polymer denitrification agent.

[0039] Comparative Example 2

[0040] The difference between this comparative example and Example 1 is that no melamine-urea-formaldehyde resin is added.

[0041] (1) Add 60 g of MOFs-based bimetallic oxide catalyst, 0.8 g of calcium carbonate, and 2.2 g of sodium hydroxide into a mixer, mix and discharge, and obtain a denitrification agent.

[0042] Comparative Example 3

[0043] The difference between this comparative example and Example 1 is that when preparing the bimetallic MOFs, 4,4'-biphenyldicarboxylic acid is used instead of 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarboxylic acid.

[0044] (1) Add 200 mL of N,N-dimethylformamide, 24 mL of water, 10 mL of ethanol, 9.5 mmol of manganese nitrate, 0.5 mmol of cobalt nitrate, and 5 mmol of 4,4'-biphenyldicarboxylic acid into a flask, stir, and then pour the solution into a hydrothermal reactor, react at 130°C for 12 h, cool, centrifuge, wash with water, ethanol, and dry to obtain bimetallic MOFs.

[0045] (2) The bimetallic MOFs were placed in a tubular furnace, heated to 500°C at a heating rate of 1°C / min, kept at this temperature for 2 hours, and cooled to obtain a MOFs-based bimetallic oxide catalyst.

[0046] (3) Add 60 g of MOFs-based bimetallic oxide catalyst, 40 g of melamine-urea-formaldehyde resin, 0.8 g of calcium carbonate, and 2.2 g of sodium hydroxide into a mixer, mix and discharge the materials to obtain a temperature-resistant polymer denitrification agent.

[0047] Comparative Example 4

[0048] The difference between this comparative example and Example 1 is that cobalt nitrate is not added when preparing the bimetallic MOFs.

[0049] (1) Add 200 mL of N,N-dimethylformamide, 24 mL of water, 10 mL of ethanol, 10 mmol of manganese nitrate, cobalt nitrate, and 5 mmol of 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarboxylic acid into a flask, stir, and then pour the solution into a hydrothermal reactor, react at 130°C for 12 h, cool, centrifuge, wash with water, ethanol, and dry to obtain manganese-based MOFs.

[0050] (2) placing the manganese-based MOFs in a tubular furnace, heating the temperature to 500°C at a heating rate of 1°C / min, keeping the temperature for 2 hours, and cooling to obtain a MOFs-based metal oxide catalyst.

[0051] (3) Add 60 g of MOFs-based metal oxide catalyst, 40 g of melamine-urea-formaldehyde resin, 0.8 g of calcium carbonate, and 2.2 g of sodium hydroxide into a mixer, mix and discharge the materials to obtain a temperature-resistant polymer denitrification agent.

[0052] The denitrification performance of the denitrifier was tested in a fixed bed reactor. The filling amount of the denitrifier was 3 mL and the reaction space velocity was 25000 h -1 The test temperature is 900-1100℃, the concentration of NO in the flue gas is 1000ppm (C0), the concentration of O2 is 8%, and N2 is used as the balance gas. The concentration of NO in the flue gas at the outlet of the fixed bed reactor after the reaction reaches a stable state is tested using a flue gas analyzer (C1).

[0053] Calculate the NO conversion rate R. R = (C0-C1) / C0×100%, the results are shown in Table 1.

[0054] Table 1 NO conversion test

[0055]

[0056]

[0057] After testing, the MOFs-based manganese-cobalt bimetallic oxide catalyst obtained by using 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarboxylic acid as a ligand and the polymer melamine-urea-formaldehyde resin as the main agent of the denitrification agent in Examples 1-3 has a NO conversion rate of 88.9-96.5% at 950°C, showing good denitrification performance.

[0058] No MOFs-based bimetallic oxide catalyst was added in Comparative Example 1. No melamine-urea-formaldehyde resin was added in Comparative Example 2. Both had poor NO conversion rates and poor denitrification performance.

[0059] In Comparative Example 3, 4,4'-biphenyldicarboxylic acid was used as a ligand to obtain a MOFs-based manganese-cobalt bimetallic oxide catalyst, which had poor catalytic performance, a NO conversion rate lower than that of Example 1, and poor denitrification performance.

[0060] In the preparation of bimetallic MOFs in Comparative Example 4, cobalt nitrate was not added. The obtained MOFs-based manganese-based metal oxide catalyst had poor catalytic performance, a NO conversion rate lower than that of Example 1, and poor denitration performance.

[0061] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A temperature-resistant polymer denitrifier, characterized in that: The temperature-resistant polymer denitrification agent comprises 60-75 parts by weight of a MOFs-based bimetallic oxide catalyst, 25-40 parts by weight of a melamine-urea-formaldehyde resin, 1.5-3 parts by weight of sodium hydroxide, and 0.6-1.2 parts by weight of calcium carbonate; The preparation method of the MOFs-based bimetallic oxide catalyst comprises: (1) Add N,N-dimethylformamide, water, ethanol, manganese source, cobalt source, and 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarboxylic acid into a flask, stir, and pour the solution into a hydrothermal reactor. After the reaction, centrifuge, wash with water and ethanol, and dry to obtain bimetallic MOFs. (2) placing the bimetallic MOFs in a tubular furnace, heating the furnace to a calcination temperature, performing heat preservation treatment, and cooling the furnace to obtain a MOFs-based bimetallic oxide catalyst.

2. The heat-resistant polymer denitrification agent according to claim 1, characterized in that: In the above (1), the volume ratio of N,N-dimethylformamide, water and ethanol is 100:(12-20):(5-15).

3. The heat-resistant polymer denitrification agent according to claim 1, characterized in that: In the above (1), the molar ratio of the manganese source, the cobalt source, and 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarboxylic acid is (88-95):(5-12):

50.

4. The heat-resistant polymer denitrification agent according to claim 1, characterized in that: In the above (1), the manganese source is manganese nitrate or manganese sulfate.

5. The heat-resistant polymer denitrification agent according to claim 1, characterized in that: In the above (1), the cobalt source is cobalt nitrate or cobalt sulfate.

6. The heat-resistant polymer denitrification agent according to claim 1, characterized in that: In the step (1), the reaction temperature is 100-130° C. and the reaction time is 12-18 h.

7. The heat-resistant polymer denitrification agent according to claim 1, characterized in that: In the above (2), the heating rate is 1-2°C / min, the calcination temperature is 500-600°C, and the insulation time is 2-3h.

8. The heat-resistant polymer denitrification agent according to claim 1, characterized in that: The preparation method of the melamine-urea-formaldehyde resin comprises: adding formaldehyde aqueous solution into a flask equipped with a condenser, adding sodium hydroxide to adjust the pH to 8-8.5, then adding urea, heating to 90-95° C., reacting for 40-60 minutes, adding formic acid to adjust the pH to 4.5-5, adding more urea, reacting for 30-40 minutes, adding sodium hydroxide to adjust the pH to 9-9.5, adding melamine, reacting for 60-90 minutes, cooling and discharging, and drying to remove water to obtain the melamine-urea-formaldehyde resin.

9. The heat-resistant polymer denitrification agent according to claim 1, characterized in that: The molar ratio of formaldehyde, urea and melamine is (4.2-4.8):(0.3-0.4):

1.

10. A method for preparing a temperature-resistant polymer denitrifying agent according to any one of claims 1 to 9, characterized in that: The preparation method comprises: adding a MOFs-based bimetallic oxide catalyst, a melamine-urea-formaldehyde resin, calcium carbonate and sodium hydroxide into a mixer, mixing and discharging the materials to obtain a temperature-resistant polymer denitrifying agent.

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