A method for preparing desulfurizing agent using fly ash

Abstract

The invention relates to the field of desulfurizers, and relates to a method for preparing a desulfurizer by using fly ash, comprising the steps of washing the fly ash with water, filtering and drying the fly ash; uniformly mixing the fly ash, additives, attapulgite, biomass and sludge, grinding and drying the mixture; calcining the dried mixture at high temperature, cooling it to room temperature, adding a desulfurization synergist, and grinding it to nanometer level to obtain a desulfurizer; the carboxyl lanthanum complex can form a stable coordination compound with sulfur-containing gas due to its empty molecular orbital and suitable electron affinity, which is helpful to adsorb and remove sulfide in flue gas; triazine sodium salt promotes the progress of mercapto-ene click reaction in a reaction system, produces a synergistic effect with other reaction components, and enhances the desulfurization performance of the entire system; the desulfurizer prepared by the invention can significantly improve the adsorption capacity of a sulfur adsorbent for sulfur-containing gas, thereby effectively reducing the sulfide content in industrial emissions, and the sulfur fixation rate is as high as 92%, which has a significant desulfurization effect.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurizing agent preparation, and in particular to a method for preparing a desulfurizing agent by utilizing fly ash. Background Art

[0002] After the incineration of municipal solid waste, fly ash equivalent to 2-5% of the original waste mass will be produced. At present, the fly ash from waste incineration is treated by melting / vitrification, cement solidification, chemical stabilization, acid or other solvent elution and other methods. Among them, melting technology is a new fly ash treatment technology in recent years. Compared with cement solidification and other methods, melting treatment technology has a thorough degree of harmlessness, high product stability, moderate operating costs, and significant reduction effect. Fly ash can also be converted into non-toxic and stable slag and used as construction materials such as roadbed and concrete.

[0003] Chinese patent CN109384228B: discloses a desulfurization and denitrification activated carbon and its preparation method, which relates to the field of activated carbon technology. The preparation method of the desulfurization and denitrification activated carbon comprises: mixing fly ash, bituminous coal, tar residue, coal tar, water, catalyst and heavy phase asphalt evenly to obtain a mixed primary material; molding the mixed primary material to obtain a carbon strip, and then carbonizing the carbon strip under anaerobic conditions to obtain a carbonized material; activating the carbonized material under process conditions of 850-920°C and 70-90pa; wherein, in the mixed primary material, the weight ratio of fly ash, bituminous coal, tar residue, coal tar, water and catalyst is 4:4-6:0.5-1.5:2-4:0.1-0.5:0.1-0.4; the catalyst is a nitrate catalyst, and the fixed carbon content in the fly ash is more than 30%. The desulfurization and denitrification activated carbon is prepared by the above preparation method.

[0004] Chinese patent CN105478001B: discloses a method for preparing a desulfurizer using waste copper and zinc catalysts, comprising the following steps: dissolving the waste copper and zinc catalysts in an alkaline solution in a water bath at 50-90°C to obtain a dissolving solution, wherein the alkaline solution is an aqueous solution of ammonia or an ammonium salt; adding an oxidant to the obtained dissolving solution to obtain a solution containing copper and zinc ions; adding a precipitant that can produce carbonate or bicarbonate ions to the solution containing copper and zinc ions to obtain a coprecipitate of copper and zinc; drying and roasting the coprecipitate to obtain a mixture of active copper oxide and zinc oxide, mixing the mixture with a binder, and then molding, drying, and roasting to obtain the desulfurizer.

[0005] Chinese patent CN112403254B: discloses a method for preparing a desulfurizer using red mud as a raw material and the desulfurizer prepared therefrom, the method comprising: mixing 5 to 8 parts by weight of red mud, 2 to 5 parts of a hydrothermal aid, 0.01 to 0.15 parts of a dispersant and 0.5 to 0.8 parts of a modifier to obtain a first mixture; subjecting the first mixture to a hydrothermal reaction and a first aging treatment, followed by solid-liquid separation to obtain hydrothermal red mud; mixing the hydrothermal red mud with an active aid, a skeleton agent, a complexing agent and an activator in a weight ratio of (7 to 9): (0.01 to 0.1): (0.5 to 1): (0.02 to 0.08): (0.01 to 0.05) to obtain a second mixture; subjecting the second mixture to a second aging treatment, followed by extrusion molding, weathering and drying to obtain a desulfurizer.

[0006] The desulfurizers prepared by current technology have defects such as complex process, high production cost and poor sulfur fixation effect. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing a desulfurizing agent by utilizing fly ash, which improves the adsorption capacity of the sulfur adsorbent for sulfur-containing gases, thereby effectively reducing the sulfide content in industrial emissions and having a significant desulfurization effect.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] A method for preparing a desulfurizing agent using fly ash comprises the following steps:

[0010] Step 1: Wash the fly ash with water, filter and dry it;

[0011] Step 2: Evenly mix the fly ash, additives, attapulgite, biomass and sludge, grind them and dry them;

[0012] Step 3: The dried mixture is calcined at high temperature, cooled to room temperature, a desulfurization synergist is added, and ground to nanometer scale to obtain a desulfurization agent;

[0013] Wherein, the preparation method of the desulfurization synergist is:

[0014] According to weight, dimethyl propylene phosphate diammonium salt, lanthanum acrylate, trimercapto-s-triazine sodium salt, cyclohexane and photoinitiator are reacted under ultraviolet light irradiation; after the reaction is completed, cyclohexane is removed by reduced pressure distillation to obtain a desulfurization synergist.

[0015] As a further solution of the present invention: in step 2 and step 3, the weight ratio of fly ash, additive, attapulgite, biomass, sludge and desulfurization enhancer is 80-100:30-40:10-20:5-10:5-10:0.05-0.5.

[0016] As a further solution of the present invention: in step 3, the weight ratio of dimethyl acryloyl phosphate-diammonium salt, lanthanum acrylate, trimercapto-s-triazine sodium salt, cyclohexane, and photoinitiator is 15-30: 0.07-0.2: 6-12: 120-160: 0.5-2.5.

[0017] As a further solution of the present invention: in step 2, the drying temperature is 100-110° C. and the time is 1-3 hours.

[0018] As a further solution of the present invention: in step 2, the additive is one of sodium metasilicate nonahydrate, gypsum, calcium hydroxide, and sodium hydroxide.

[0019] As a further solution of the present invention: in step 2, the biomass is one of straw, wood chips, rice husks, wood waste, and livestock manure.

[0020] As a further solution of the present invention: in step 2, the grinding time is 5-10 min.

[0021] As a further solution of the present invention: Step 3, the calcination temperature is 1000-1200° C., and the time is 1-3 hours.

[0022] As a further embodiment of the present invention: the photoinitiator is one of 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, α-hydroxyacetophenone, and dialkoxyacetophenone.

[0023] As a further solution of the present invention: the conditions of ultraviolet light irradiation are: the wavelength of ultraviolet light is 200-370 nanometers, and the irradiation time is 20-40 minutes.

[0024] Beneficial effects of the present invention:

[0025] The present invention utilizes carboxyl lanthanum complexes because they have empty molecular orbitals and suitable electron affinity, and can form stable coordination compounds with sulfur-containing gases, which helps to adsorb and remove sulfides in flue gas; triazine sodium salt promotes the progress of mercapto-ene click reaction in the reaction system and produces synergistic effects with other reaction components, thereby enhancing the desulfurization performance of the entire system;

[0026] Reaction mechanism of desulfurization synergist:

[0027] In the preparation method of the desulfurization synergist, dimethyl propylene phosphate-diammonium salt and trimercapto-s-triazine sodium salt are the core reactants; these chemical substances react chemically under the irradiation of ultraviolet light to generate a desulfurization synergist with specific functions;

[0028] Dimethyl propylene phosphate-diammonium salt: As a multifunctional compound, it undergoes photo-initiated free radical polymerization under ultraviolet light irradiation. The unsaturated double bonds (olefin structure) in dimethyl propylene phosphate-diammonium salt can react with free radicals to form high molecular polymers.

[0029] Lanthanum acrylate acts as a catalyst or participating substance in this reaction. Lanthanide elements have multiple coordination positions and can coordinate with various functional groups such as carboxyl and phosphate groups.

[0030] The thiol group (-SH) in the sodium salt of trimercapto-s-triazine is a very active functional group that easily loses hydrogen atoms to form thiol free radicals. These thiol free radicals can attack the olefin double bonds in dimethyl allyl phosphate-diammonium salt and lanthanum acrylate, triggering a thiol-olefin click chemistry reaction.

[0031] Click chemistry is a fast and highly selective chemical reaction, which is usually used for the synthesis of functional materials and bioconjugation. Here, the sodium salt of trithiolstriazine can be effectively connected with dimethylallyl phosphate-diammonium salt and lanthanum acrylate through a click reaction under ultraviolet light excitation.

[0032] Desulfurization principle

[0033] Desulfurization enhancers can significantly improve the adsorption capacity of sulfur adsorbents for sulfur-containing gases, thereby effectively reducing the sulfide content in industrial emissions;

[0034] Desulfurization enhancers may contain various functional groups, such as amine and phosphate groups, which can react with SO during the desulfurization process. 2 The sulfides such as sulfide react chemically or physically adsorb, thereby increasing the removal rate of sulfide. Through the click reaction under ultraviolet light excitation, the sodium salt of trithiolstriazine can be effectively connected with dimethyl propylene phosphate-diammonium salt to form a high molecular polymer with specific functions. This polymer not only contains a variety of functional groups, such as amine and phosphate groups, but also provides abundant reaction sites and interfaces, thereby optimizing the desulfurization process. This is mainly because the high molecular structure of the desulfurization enhancer helps to increase the gaseous SO 2 The contact and reaction efficiency with the desulfurizer. In addition, the use of this desulfurization synergist can also reduce the energy and chemical consumption required in the traditional desulfurization process, reduce the generation of secondary pollution, and make the entire desulfurization process more environmentally friendly.

[0035] The polymer structure of the desulfurization enhancer provides more reaction sites and interfaces, making the gaseous SO 2It is easier to contact and react with the desulfurizer. Lanthanum carboxyl complexes can form stable coordination compounds with sulfur-containing gases due to their empty molecular orbitals and suitable electron affinity, which helps to adsorb and remove sulfides in flue gas; triazine sodium salt promotes the thiol-ene click reaction in the reaction system and produces a synergistic effect with other reaction components, enhancing the desulfurization performance of the entire system.

[0036] The use of this desulfurization enhancer can reduce the energy and chemical consumption required in the traditional desulfurization process, reduce the generation of secondary pollution, and make the entire desulfurization process more environmentally friendly.

[0037] In summary, the research and development and application of desulfurization enhancers are of great significance for improving desulfurization efficiency and reducing environmental pollution. Desulfurization enhancers prepared by UV-induced click chemistry and other related chemical reactions have significantly optimized the desulfurization process, improved the removal efficiency of sulfides, and reduced environmental impact; in the future, research in this field can further explore new reactants and preparation methods to achieve more efficient and environmentally friendly desulfurization technology;

[0038] By utilizing the reaction characteristics of phosphate-diammonium salt, carboxyl lanthanum complex and triazine sodium salt, the prepared desulfurization enhancer may have good thermal stability and chemical stability, which is crucial to improving the service life and environmental adaptability of desulfurization materials;

[0039] The use of these chemicals not only improves the desulfurization efficiency, but also makes the entire desulfurization process more environmentally friendly and economical, optimizing the traditional desulfurization process by reducing energy consumption and reducing the generation of by-products. DETAILED DESCRIPTION

[0040] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0041] The present invention is a method for preparing a desulfurizing agent using fly ash, comprising the following steps:

[0042] S1: Wash the fly ash with water twice, filter and dry;

[0043] S2: Weigh 80g of dried fly ash, 30g of additives, 10g of attapulgite, 5g of biomass, and 5g of sludge, mix them evenly, grind them, and dry them;

[0044] S3: The dried mixture is calcined at high temperature, cooled to room temperature, 0.05 g of a desulfurization synergist is added, and ground to nanometer scale to obtain a desulfurization agent.

[0045] The drying temperature is 100° C. and the drying time is 1 hour.

[0046] The additive is sodium metasilicate nonahydrate.

[0047] The biomass is straw.

[0048] The grinding time is 5 min.

[0049] The calcination temperature is 1000° C. and the calcination time is 1 hour.

[0050] The preparation method of the desulfurization synergist is as follows:

[0051] 15g of dimethyl propylene phosphate diammonium salt, 0.07g of lanthanum acrylate, 6g of trimercapto-s-triazine sodium salt, 120g of cyclohexane, and 0.5g of photoinitiator are irradiated with ultraviolet light of a wavelength of 200 nanometers for 20 minutes; after the reaction is completed, the cyclohexane is removed by reduced pressure distillation to obtain a desulfurization synergist.

[0052] The photoinitiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone. Example 2

[0053] The present invention is a method for preparing a desulfurizing agent using fly ash, comprising the following steps:

[0054] S1: Wash the fly ash with water twice, filter and dry;

[0055] S2: Weigh 85g of dried fly ash, 33g of additives, 14g of attapulgite, 6g of biomass, and 6g of sludge, mix them evenly, grind them, and dry them;

[0056] S3: The dried mixture is calcined at high temperature, cooled to room temperature, 0.2 g of a desulfurization synergist is added, and ground to nanometer scale to obtain a desulfurization agent.

[0057] The drying temperature is 105° C. and the drying time is 2 hours.

[0058] The additive is gypsum.

[0059] The biomass is wood chips.

[0060] The grinding time is 6 minutes.

[0061] The calcination temperature is 1050°C and the calcination time is 2h.

[0062] The preparation method of the desulfurization synergist is as follows:

[0063] 20g of dimethyl propylene phosphate diammonium salt, 0.1g of lanthanum acrylate, 8g of trimercapto-s-triazine sodium salt, 130g of cyclohexane, and 1g of photoinitiator are irradiated with ultraviolet light of a wavelength of 260 nanometers for 25 minutes; after the reaction is completed, the cyclohexane is removed by reduced pressure distillation to obtain a desulfurization synergist.

[0064] The photoinitiator is α-hydroxyacetophenone. Example 3

[0065] The present invention is a method for preparing a desulfurizing agent using fly ash, comprising the following steps:

[0066] S1: Wash the fly ash with water three times, filter and dry;

[0067] S2: Weigh 95g of dried fly ash, 38g of additives, 18g of attapulgite, 9g of biomass, and 9g of sludge, mix them evenly, grind them, and dry them;

[0068] S3: The dried mixture is calcined at high temperature, cooled to room temperature, 0.4 g of a desulfurization synergist is added, and ground to nanometer scale to obtain a desulfurization agent.

[0069] The drying temperature is 105° C. and the drying time is 2 hours.

[0070] The additive is calcium hydroxide.

[0071] The biomass is rice husk.

[0072] The grinding time is 8 minutes.

[0073] The calcination temperature is 1150° C. and the calcination time is 2 hours.

[0074] The preparation method of the desulfurization synergist is as follows:

[0075] 25g of dimethyl propylene phosphate diammonium salt, 0.15g of lanthanum acrylate, 10g of trimercapto-s-triazine sodium salt, 150g of cyclohexane, and 2g of photoinitiator are irradiated with ultraviolet light of a wavelength of 320 nanometers for 35 minutes; after the reaction is completed, the cyclohexane is removed by reduced pressure distillation to obtain a desulfurization synergist.

[0076] The photoinitiator is α-hydroxyacetophenone. Example 4

[0077] The present invention is a method for preparing a desulfurizing agent by utilizing fly ash, comprising the following steps:

[0078] S1: Wash the fly ash with water three times, filter and dry;

[0079] S2: Weigh 100g of dried fly ash, 40g of additives, 20g of attapulgite, 10g of biomass, and 10g of sludge, mix them evenly, grind them, and dry them;

[0080] S3: The dried mixture is calcined at high temperature, cooled to room temperature, 0.5 g of a desulfurization synergist is added, and ground to nanometer scale to obtain a desulfurization agent.

[0081] The drying temperature is 110° C. and the drying time is 3 hours.

[0082] The additive is sodium hydroxide.

[0083] The biomass is wood waste.

[0084] The grinding time is 10 min.

[0085] The calcination temperature is 1200° C. and the calcination time is 3 hours.

[0086] The preparation method of the desulfurization synergist is as follows:

[0087] 30g of dimethyl propylene phosphate diammonium salt, 0.2g of lanthanum acrylate, 12g of trimercapto-s-triazine sodium salt, 160g of cyclohexane, and 2.5g of photoinitiator are irradiated with ultraviolet light of a wavelength of 370 nanometers for 40 minutes; after the reaction is completed, the cyclohexane is removed by reduced pressure distillation to obtain a desulfurization synergist.

[0088] The photoinitiator is dialkoxyacetophenone. Comparative Example 1

[0089] As a comparative example, this example is consistent with Example 1 except that no desulfurization synergist is added.

[0090] The desulfurization rate of the desulfurizer prepared in this comparative example is found to be 48% through analysis and calculation. Comparative Example 2

[0091] As a comparative example, this example is consistent with Example 1 except that dimethyl propylene phosphate diammonium salt is not added.

[0092] The analysis and calculation showed that the sulfur fixation rate of the desulfurizer prepared in this comparative example was 57%. Comparative Example 3

[0093] As a comparative example, this example is the same as Example 1 except that trimercapto-s-triazine sodium salt is not added.

[0094] The desulfurization rate of the desulfurizer prepared in this comparative example was found to be 63% through analysis and calculation.

[0095] Performance Testing:

[0096] The performance test of the desulfurizers of Examples 1-4 and Comparative Examples 1-3 was carried out: 50 mg of desulfurizer was loaded into a fluidized bed reactor, the reaction temperature was 900 ° C, the reaction time was 150 min, and the SO 2 The content is 0.15%, and the gas flow rate is 500cm 3 / min, the sulfur fixation rate is calculated by the mass change before and after the reaction; the test results are shown in the following table:

[0097] Sulfur fixation rate (%) Example 1 85 Example 2 87 Example 3 89 Example 4 92 Comparative Example 1 48 Comparative Example 2 57 Comparative Example 3 63

[0098] Through the data analysis of the above examples and comparative examples, the desulfurization synergist prepared by the present invention can significantly improve the sulfur fixation rate, thereby effectively reducing the sulfide content of the emission.

[0099] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for preparing a desulfurizing agent using fly ash, characterized in that: The following steps are involved: Step 1: Wash the fly ash with water, filter and dry it; Step 2: Evenly mix the fly ash, additives, attapulgite, biomass and sludge, grind them and dry them; Step 3: The dried mixture is calcined at high temperature, cooled to room temperature, a desulfurization synergist is added, and ground to nanometer scale to obtain a desulfurization agent; Wherein, the preparation method of the desulfurization synergist is: According to weight, dimethyl acryloyl phosphate diammonium salt, lanthanum acrylate, trimercapto-s-triazine sodium salt, cyclohexane, and a photoinitiator are reacted under ultraviolet light irradiation; after the reaction is completed, the cyclohexane is removed by reduced pressure distillation to obtain a desulfurization synergist; In step 2 and step 3, the weight ratio of fly ash, additive, attapulgite, biomass, sludge and desulfurization synergist is 80-100:30-40:10-20:5-10:5-10:0.05-0.5; In step 2, the additive is one of sodium metasilicate nonahydrate, gypsum, calcium hydroxide, and sodium hydroxide.

2. The method for preparing a desulfurizing agent using fly ash according to claim 1, characterized in that: In step 3, the weight ratio of dimethyl acryloyl phosphate-diammonium salt, lanthanum acrylate, trimercapto-s-triazine sodium salt, cyclohexane, and photoinitiator is 15-30: 0.07-0.2: 6-12: 120-160: 0.5-2.

5.

3. The method for preparing a desulfurizing agent using fly ash according to claim 1, characterized in that: In step 2, the drying temperature is 100-110° C. and the time is 1-3 hours.

4. The method for preparing a desulfurizing agent using fly ash according to claim 1, characterized in that: In step 2, the biomass is one of straw, wood chips, rice husks, wood waste, and livestock manure.

5. The method for preparing a desulfurizing agent using fly ash according to claim 1, characterized in that: In step 2, the grinding time is 5-10 min.

6. The method for preparing a desulfurizing agent using fly ash according to claim 1, characterized in that: Step 3, the calcination temperature is 1000-1200°C and the time is 1-3h.

7. The method for preparing a desulfurizing agent using fly ash according to claim 1, characterized in that: The photoinitiator is one of 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, α-hydroxyacetophenone and dialkoxyacetophenone.

8. The method for preparing a desulfurizing agent using fly ash according to claim 1, characterized in that: The conditions for ultraviolet light irradiation are: the wavelength of ultraviolet light is 200-370 nanometers, and the irradiation time is 20-40 minutes.