Composite desulfurizer for waste gas treatment and preparation method thereof

Abstract

The invention discloses a composite desulfurizer for waste gas treatment and a preparation method thereof, relates to the technical field of desulfurizers, and aims to improve treatment of sulfur-containing gas in waste gas and avoid the problem that the desulfurization performance of part of desulfurizers is reduced at high temperature. The preparation method comprises the following steps: taking 3-hydroxypropylamine as a raw material, and reacting with ethane tricarboxylic acid to obtain an intermediate containing a three-arm amino structure; on the basis, the modified triazine sulfur removal agent with the triazine ring structure is prepared by further mixing the modified triazine sulfur removal agent with the methoxyl and amino structure with 3-methoxyl propylamine, and the modified triazine sulfur removal agent with the triazine ring structure is prepared by utilizing the characteristics of high molecular weight, addition of nitrogen element and increase of molecular stability. Therefore, the finally prepared desulfurizer still has excellent desulfurization capacity at high temperature, the defect of poor desulfurization efficiency of high-temperature waste gas is avoided, and the pollution to the environment is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurizing agents, in particular to a composite desulfurizing agent for waste gas treatment and a preparation method thereof. Background Art

[0002] With the acceleration of my country's industrialization process and the growth of energy demand, the emission problem of sulfur-containing waste gas (such as SO2, H2S, etc.) is becoming increasingly serious. This type of gas not only has a serious corrosive effect on industrial equipment, but the long-term presence of sulfides will cause corrosion to pipelines, reactors, furnaces and other important equipment, shorten the service life of equipment, increase maintenance costs, and even cause equipment failure and production stagnation in severe cases. In addition, sulfur-containing gases are highly toxic and irritating, posing a threat to human health, and will also cause environmental pollution, resulting in serious air, soil and water pollution. Therefore, in order to reduce the emission of sulfur-containing gases in waste gas, the research and development and application of waste gas desulfurizers are particularly important. Modern waste gas treatment technology urgently needs a desulfurizer that can efficiently remove sulfides in waste gas, is easy to operate, cost-controlled and environmentally friendly. Summary of the invention

[0003] The object of the present invention is to provide a composite desulfurizing agent for waste gas treatment and a preparation method thereof, so as to solve the problems raised in the prior art.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a method for preparing a composite desulfurizer for waste gas treatment, comprising the following steps: after mixing a modified triazine desulfurizer with tetrahydrothiophene, adding a mixed solvent consisting of methyldiethanolamine and ethylenediamine thereto, stirring and dispersing them uniformly, adding triethylene glycol and deionized water thereto and mixing, mixing again for 30-120 minutes, adding sodium hydroxide, stirring uniformly, and discharging to obtain a composite desulfurizer for waste gas treatment.

[0005] Furthermore, the composite desulfurizer for waste gas treatment comprises, by weight, 30-45 parts of modified triazine desulfurizer, 15-22 parts of tetrahydrothiophene, 10-15 parts of methyldiethanolamine, 8-12 parts of ethylenediamine, 3-6 parts of triethylene glycol, 28-35 parts of deionized water, and 1-3 parts of sodium hydroxide.

[0006] Furthermore, the preparation method of the modified triazine desulfurizer comprises the following steps: a. Under nitrogen atmosphere protection, 3-hydroxypropylamine and di-tert-butyl dicarbonate are added to tetrahydrofuran, stirred at 20-35°C for 1-2h, ethanetricarboxylic acid is added thereto, the temperature is raised to 45-66°C, stirred, refluxed for 12-24h, excess solvent is removed by rotary evaporation, and the resulting product is dispersed in a hydrochloric acid solution, stirred at room temperature for 5-8h, heated to 68-75°C, stirred to react until di-tert-butyl dicarbonate evaporates, excess solvent is removed by rotary evaporation, the dried product is collected, heated to 108-110°C under nitrogen atmosphere, kept warm for 10-15min, and cooled to room temperature to obtain an intermediate; b. Add the intermediate and 3-methoxypropylamine to tetrahydrofuran, stir and mix evenly, protect under nitrogen atmosphere, raise the temperature to 55-65°C, add formaldehyde aqueous solution dropwise for 2-4 hours, continue stirring and reacting for 0.5-1 hour after the addition, and remove excess solvent by rotary evaporation to obtain a modified triazine desulfurizer.

[0007] Furthermore, in step a, the mass ratio of the 3-hydroxypropylamine, di-tert-butyl dicarbonate, and ethanetricarboxylic acid is 1:(2.7-3):(0.65-0.75) in parts by weight.

[0008] Furthermore, in step b, the mass ratio of the intermediate to 3-methoxypropylamine is 1:(1.2-1.4) by weight.

[0009] Furthermore, in step b, the concentration of the formaldehyde aqueous solution is 35-40wt%.

[0010] Furthermore, in step b, the mass volume ratio of the 3-methoxypropylamine to the formaldehyde aqueous solution is 1 g: (1.3-1.5) mL.

[0011] Furthermore, a composite desulfurizing agent for waste gas treatment is prepared by the above method.

[0012] Compared with the prior art, the present invention has the following beneficial effects: In order to improve the treatment of sulfur-containing gas in exhaust gas, the present invention prepares a composite desulfurizer containing a modified triazine desulfurizer. Compared with conventional liquid desulfurizers, triazine desulfurizers have good desulfurization performance, no odor and good thermal stability. However, in the current exhaust gas emission, due to the different types of exhaust gas, high-temperature gas is often encountered. At high temperatures, some desulfurizers will have a problem of reduced desulfurization performance, thereby increasing the sulfur content in the exhaust gas and causing the defect of unqualified pollution emissions; Therefore, the present invention performs a modification treatment on the triazine desulfurizer; the present invention first uses 3-hydroxypropylamine as a raw material, reacts it with an amino protecting agent di-tert-butyl dicarbonate to protect the amino group therein, reacts it with ethanetricarboxylic acid again, releases the amino group in an acidic environment, evaporates the di-tert-butyl dicarbonate at a high temperature, and heats the product again to remove the hydrogen chloride impurity in the product, thereby preparing an intermediate containing a three-arm amino structure; On this basis, the present invention further mixes it with 3-methoxypropylamine containing methoxy and amino structures, and then reacts with formaldehyde again, and uses the amine-aldehyde condensation method to prepare a modified triazine desulfurizer with a triazine ring structure, wherein the intermediate containing a three-arm amino structure can effectively increase the molecular weight of the prepared desulfurizer, and the large number of nitrogen atoms introduced therein can also play a role in increasing the molecular stability, so that the desulfurizer finally prepared still has excellent desulfurization ability at high temperature, avoids the defect of poor desulfurization efficiency of high-temperature exhaust gas, and reduces pollution to the environment. DETAILED DESCRIPTION

[0013] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0014] Example 1. A method for preparing a composite desulfurizing agent for waste gas treatment, comprising the following steps: After mixing 30 parts of modified triazine desulfurizer and 18 parts of tetrahydrothiophene by weight, a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto, and after stirring and dispersing evenly, 5 parts of triethylene glycol and 30 parts of deionized water were added thereto and mixed, and after mixing again for 90 minutes, 1 part of sodium hydroxide was added, and after stirring evenly, the material was discharged to obtain a composite desulfurizer for waste gas treatment; The preparation method of the modified triazine desulfurizer comprises the following steps: a. Under nitrogen atmosphere protection, 1 part of 3-hydroxypropylamine and 2.7 parts of di-tert-butyl dicarbonate were added to tetrahydrofuran by weight, stirred at 30°C for 1h, 0.65 parts of ethanetricarboxylic acid were added thereto, the temperature was raised to 60°C, stirred, refluxed for 12h in the dark, and the excess solvent was removed by rotary evaporation. The resulting product was dispersed in a hydrochloric acid solution, stirred at room temperature for 8h, heated to 72-75°C, stirred to react until di-tert-butyl dicarbonate evaporated, the excess solvent was removed by rotary evaporation, the dried product was collected, heated to 110°C under nitrogen atmosphere, kept warm for 15min, and cooled to room temperature to obtain an intermediate; b. By weight, 1 part of the intermediate and 1.2 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed evenly, and the mixture was heated to 60°C under nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was continued with stirring for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer; The concentration of the formaldehyde aqueous solution added in step b is 37 wt %, and the mass volume ratio of the added amount of 3-methoxypropylamine to the formaldehyde aqueous solution is 1 g:1.4 mL.

[0015] Example 2. A method for preparing a composite desulfurizer for waste gas treatment, comprising the following steps: Compared with Example 1, this example increases the amount of modified triazine desulfurizer added to the composite desulfurizer for waste gas treatment; By weight, 45 parts of modified triazine desulfurizer and 18 parts of tetrahydrothiophene were mixed, and a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto. After stirring and dispersing evenly, 5 parts of triethylene glycol and 30 parts of deionized water were added thereto and mixed. After mixing again for 90 minutes, 1 part of sodium hydroxide was added, and after stirring evenly, the material was discharged to obtain a composite desulfurizer for waste gas treatment; The preparation method of the modified triazine desulfurizer comprises the following steps: a. Under nitrogen atmosphere protection, 1 part of 3-hydroxypropylamine and 2.7 parts of di-tert-butyl dicarbonate were added to tetrahydrofuran by weight, stirred at 30°C for 1h, 0.65 parts of ethanetricarboxylic acid were added thereto, the temperature was raised to 60°C, stirred, refluxed for 12h in the dark, and the excess solvent was removed by rotary evaporation. The resulting product was dispersed in a hydrochloric acid solution, stirred at room temperature for 8h, heated to 72-75°C, stirred to react until di-tert-butyl dicarbonate evaporated, the excess solvent was removed by rotary evaporation, the dried product was collected, heated to 110°C under nitrogen atmosphere, kept warm for 15min, and cooled to room temperature to obtain an intermediate; b. By weight, 1 part of the intermediate and 1.2 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed evenly, and the mixture was heated to 60°C under nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was continued with stirring for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer; The concentration of the formaldehyde aqueous solution added in step b is 37 wt %, and the mass volume ratio of the added amount of 3-methoxypropylamine to the formaldehyde aqueous solution is 1 g:1.4 mL.

[0016] Example 3. A method for preparing a composite desulfurizing agent for waste gas treatment, comprising the following steps: Compared with Example 1, the amount of di-tert-butyl dicarbonate added in step a is increased in this example; After mixing 30 parts of modified triazine desulfurizer and 18 parts of tetrahydrothiophene by weight, a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto, and after stirring and dispersing evenly, 5 parts of triethylene glycol and 30 parts of deionized water were added thereto and mixed, and after mixing again for 90 minutes, 1 part of sodium hydroxide was added, and after stirring evenly, the material was discharged to obtain a composite desulfurizer for waste gas treatment; The preparation method of the modified triazine desulfurizer comprises the following steps: a. Under nitrogen atmosphere protection, 1 part of 3-hydroxypropylamine and 3 parts of di-tert-butyl dicarbonate were added to tetrahydrofuran by weight, stirred at 30°C for 1 hour, 0.65 parts of ethanetricarboxylic acid were added thereto, the temperature was raised to 60°C, stirred, refluxed for 12 hours in the dark, and the excess solvent was removed by rotary evaporation. The resulting product was dispersed in a hydrochloric acid solution, stirred at room temperature for 8 hours, heated to 72-75°C, stirred to react until di-tert-butyl dicarbonate evaporated, the excess solvent was removed by rotary evaporation, and the dried product was collected. Under nitrogen atmosphere, the temperature was raised to 110°C, kept warm for 15 minutes, and then cooled to room temperature to obtain an intermediate; b. By weight, 1 part of the intermediate and 1.2 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed evenly, and the mixture was heated to 60°C under nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was continued with stirring for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer; The concentration of the formaldehyde aqueous solution added in step b is 37 wt %, and the mass volume ratio of the added amount of 3-methoxypropylamine to the formaldehyde aqueous solution is 1 g:1.4 mL.

[0017] Example 4. A method for preparing a composite desulfurizing agent for waste gas treatment, comprising the following steps: Compared with Example 3, this example increases the amount of ethanetricarboxylic acid added in step a; After mixing 30 parts of modified triazine desulfurizer and 18 parts of tetrahydrothiophene by weight, a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto, and after stirring and dispersing evenly, 5 parts of triethylene glycol and 30 parts of deionized water were added thereto and mixed, and after mixing again for 90 minutes, 1 part of sodium hydroxide was added, and after stirring evenly, the material was discharged to obtain a composite desulfurizer for waste gas treatment; The preparation method of the modified triazine desulfurizer comprises the following steps: a. Under nitrogen atmosphere protection, 1 part of 3-hydroxypropylamine and 3 parts of di-tert-butyl dicarbonate were added to tetrahydrofuran by weight, stirred at 30°C for 1 hour, 0.75 parts of ethanetricarboxylic acid were added thereto, the temperature was raised to 60°C, stirred, refluxed for 12 hours in the dark, and the excess solvent was removed by rotary evaporation. The resulting product was dispersed in a hydrochloric acid solution, stirred at room temperature for 8 hours, heated to 72-75°C, stirred to react until di-tert-butyl dicarbonate evaporated, the excess solvent was removed by rotary evaporation, and the dried product was collected. Under nitrogen atmosphere, the temperature was raised to 110°C, kept warm for 15 minutes, and then cooled to room temperature to obtain an intermediate; b. By weight, 1 part of the intermediate and 1.2 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed evenly, and the mixture was heated to 60°C under nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was continued with stirring for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer; The concentration of the formaldehyde aqueous solution added in step b is 37 wt %, and the mass volume ratio of the added amount of 3-methoxypropylamine to the formaldehyde aqueous solution is 1 g:1.4 mL.

[0018] Example 5. A method for preparing a composite desulfurizing agent for waste gas treatment, comprising the following steps: Compared with Example 4, this example increases the amount of 3-methoxypropylamine added in step b; After mixing 30 parts of modified triazine desulfurizer and 18 parts of tetrahydrothiophene by weight, a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto, and after stirring and dispersing evenly, 5 parts of triethylene glycol and 30 parts of deionized water were added thereto and mixed, and after mixing again for 90 minutes, 1 part of sodium hydroxide was added, and after stirring evenly, the material was discharged to obtain a composite desulfurizer for waste gas treatment; The preparation method of the modified triazine desulfurizer comprises the following steps: a. Under nitrogen atmosphere protection, 1 part of 3-hydroxypropylamine and 3 parts of di-tert-butyl dicarbonate were added to tetrahydrofuran by weight, stirred at 30°C for 1 hour, 0.75 parts of ethanetricarboxylic acid were added thereto, the temperature was raised to 60°C, stirred, refluxed for 12 hours in the dark, and the excess solvent was removed by rotary evaporation. The resulting product was dispersed in a hydrochloric acid solution, stirred at room temperature for 8 hours, heated to 72-75°C, stirred to react until di-tert-butyl dicarbonate evaporated, the excess solvent was removed by rotary evaporation, and the dried product was collected. Under nitrogen atmosphere, the temperature was raised to 110°C, kept warm for 15 minutes, and then cooled to room temperature to obtain an intermediate; b. By weight, 1 part of the intermediate and 1.4 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed evenly, and the mixture was heated to 60°C under nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was continued with stirring for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer; The concentration of the formaldehyde aqueous solution added in step b is 37 wt %, and the mass volume ratio of the added amount of 3-methoxypropylamine to the formaldehyde aqueous solution is 1 g:1.4 mL.

[0019] Example 6. A method for preparing a composite desulfurizing agent for waste gas treatment, comprising the following steps: Compared with Example 5, this example increases the amount of modified triazine desulfurizer added to the composite desulfurizer for waste gas treatment; After mixing 30 parts of modified triazine desulfurizer and 18 parts of tetrahydrothiophene by weight, a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto, and after stirring and dispersing evenly, 5 parts of triethylene glycol and 30 parts of deionized water were added thereto and mixed, and after mixing again for 90 minutes, 1 part of sodium hydroxide was added, and after stirring evenly, the material was discharged to obtain a composite desulfurizer for waste gas treatment; The preparation method of the modified triazine desulfurizer comprises the following steps: a. Under nitrogen atmosphere protection, 1 part of 3-hydroxypropylamine and 3 parts of di-tert-butyl dicarbonate were added to tetrahydrofuran by weight, stirred at 30°C for 1 hour, 0.75 parts of ethanetricarboxylic acid were added thereto, the temperature was raised to 60°C, stirred, refluxed for 12 hours in the dark, and the excess solvent was removed by rotary evaporation. The resulting product was dispersed in a hydrochloric acid solution, stirred at room temperature for 8 hours, heated to 72-75°C, stirred to react until di-tert-butyl dicarbonate evaporated, the excess solvent was removed by rotary evaporation, and the dried product was collected. Under nitrogen atmosphere, the temperature was raised to 110°C, kept warm for 15 minutes, and then cooled to room temperature to obtain an intermediate; b. By weight, 1 part of the intermediate and 1.4 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed evenly, and the mixture was heated to 60°C under nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was continued with stirring for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer; The concentration of the formaldehyde aqueous solution added in step b is 37 wt %, and the mass volume ratio of the added amount of 3-methoxypropylamine to the formaldehyde aqueous solution is 1 g:1.4 mL.

[0020] Comparative Example 1. A method for preparing a composite desulfurizing agent for waste gas treatment, comprising the following steps: Compared with Example 1, this comparative example did not perform step a treatment; By weight, 30 parts of the modified desulfurizer 1 and 18 parts of tetrahydrothiophene were mixed, and a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto. After stirring and dispersing evenly, 5 parts of triethylene glycol and 30 parts of deionized water were added thereto and mixed. After mixing again for 90 minutes, 1 part of sodium hydroxide was added, and after stirring evenly, the material was discharged to obtain a composite desulfurizer for waste gas treatment; The preparation method of the modified desulfurizer 1 comprises the following steps: b. 1.2 parts by weight of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed, and then heated to 60°C under nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was continued with stirring for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified desulfurizer 1; The concentration of the formaldehyde aqueous solution added in step b is 37 wt %, and the mass volume ratio of the added amount of 3-methoxypropylamine to the formaldehyde aqueous solution is 1 g:1.4 mL.

[0021] Comparative Example 2. A method for preparing a composite desulfurizing agent for waste gas treatment, comprising the following steps: Compared with Example 1, this comparative example did not perform step b. By weight, 30 parts of modified desulfurizer 2 and 18 parts of tetrahydrothiophene were mixed, and a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto. After stirring and dispersing evenly, 5 parts of triethylene glycol and 30 parts of deionized water were added thereto and mixed. After mixing again for 90 minutes, 1 part of sodium hydroxide was added, and after stirring evenly, the material was discharged to obtain a composite desulfurizer for waste gas treatment; Wherein, the preparation method of the modified desulfurizer 2 comprises the following steps: a. Under nitrogen atmosphere protection, 1 part of 3-hydroxypropylamine and 2.7 parts of di-tert-butyl dicarbonate were added to tetrahydrofuran by weight, stirred at 30°C for 1 hour, and then 0.65 parts of ethanetricarboxylic acid were added thereto. The temperature was raised to 60°C, stirred, and refluxed for 12 hours in the dark. After removing the excess solvent by rotary evaporation, the resulting product was dispersed in a hydrochloric acid solution, stirred at room temperature for 8 hours, and then heated to 72-75°C. After stirring and reacting until di-tert-butyl dicarbonate evaporated, the excess solvent was removed by rotary evaporation, and the dried product was collected. Under nitrogen atmosphere, the temperature was raised to 110°C, kept warm for 15 minutes, and then cooled to room temperature to obtain a modified desulfurizer 2.

[0022] Comparative Example 3. A method for preparing a composite desulfurizing agent for waste gas treatment, comprising the following steps: Compared with Example 1, this comparative example uses 1,3,5-tris(2-hydroxyethyl)-hexahydro-s-triazine to replace the modified triazine desulfurizer; According to the weight percentage, 30 parts of 1,3,5-tris(2-hydroxyethyl)-hexahydro-s-triazine and 18 parts of tetrahydrothiophene are mixed, and a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine is added thereto. After stirring and dispersing evenly, 5 parts of triethylene glycol and 30 parts of deionized water are added thereto and mixed. After mixing again for 90 minutes, 1 part of sodium hydroxide is added, and after stirring evenly, the material is discharged to obtain a composite desulfurizer for waste gas treatment.

[0023] Detection: The waste gas contains 1000mg / Nm3 of organic sulfur 3 , H2S 20%, the exhaust gas is mixed with a liquid desulfurizer at a temperature of 60°C in an absorption tower, the purified gas after desulfurization is discharged and tested, and the organic sulfur and sulfur dioxide content before and after is tested; The waste gas contains organic sulfur 1000mg / Nm 3 , H2S 20%, the exhaust gas is mixed with a liquid desulfurizer at a temperature of 90°C in an absorption tower, the purified gas after desulfurization is discharged and tested, and the organic sulfur and sulfur dioxide content before and after is tested; The test results are shown in the table below:

[0024] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a composite desulfurizer for waste gas treatment, characterized in that: After the modified triazine desulfurizer is mixed with tetrahydrothiophene, a mixed solvent consisting of methyldiethanolamine and ethylenediamine is added thereto, and after being stirred and dispersed evenly, triethylene glycol and deionized water are added thereto and mixed, and after mixing again for 30-120 minutes, sodium hydroxide is added, stirred evenly, and discharged to obtain a composite desulfurizer for waste gas treatment.

2. The method for preparing a composite desulfurizing agent for waste gas treatment according to claim 1, characterized in that: In terms of weight, the composite desulfurizer for waste gas treatment comprises 30-45 parts of modified triazine desulfurizer, 15-22 parts of tetrahydrothiophene, 10-15 parts of methyldiethanolamine, 8-12 parts of ethylenediamine, 3-6 parts of triethylene glycol, 28-35 parts of deionized water, and 1-3 parts of sodium hydroxide.

3. The method for preparing a composite desulfurizing agent for waste gas treatment according to claim 1, characterized in that: The preparation method of the modified triazine desulfurizer comprises the following steps: a. Under nitrogen atmosphere protection, 3-hydroxypropylamine and di-tert-butyl dicarbonate are added to tetrahydrofuran, stirred at 20-35°C for 1-2h, ethanetricarboxylic acid is added thereto, the temperature is raised to 45-66°C, stirred, refluxed for 12-24h, excess solvent is removed by rotary evaporation, and the resulting product is dispersed in a hydrochloric acid solution, stirred at room temperature for 5-8h, heated to 68-75°C, stirred to react until di-tert-butyl dicarbonate evaporates, excess solvent is removed by rotary evaporation, the dried product is collected, heated to 108-110°C under nitrogen atmosphere, kept warm for 10-15min, and cooled to room temperature to obtain an intermediate; b. Add the intermediate and 3-methoxypropylamine to tetrahydrofuran, stir and mix evenly, protect under nitrogen atmosphere, raise the temperature to 55-65°C, add formaldehyde aqueous solution dropwise for 2-4 hours, continue stirring and reacting for 0.5-1 hour after the addition, and remove excess solvent by rotary evaporation to obtain a modified triazine desulfurizer.

4. The method for preparing a composite desulfurizing agent for waste gas treatment according to claim 3, characterized in that: In step a, the mass ratio of the 3-hydroxypropylamine, di-tert-butyl dicarbonate and ethanetricarboxylic acid is 1:(2.7-3):(0.65-0.75) in parts by weight.

5. The method for preparing a composite desulfurizing agent for waste gas treatment according to claim 3, characterized in that: In step b, the mass ratio of the intermediate to 3-methoxypropylamine is 1:(1.2-1.4) by weight.

6. The method for preparing a composite desulfurizing agent for waste gas treatment according to claim 3, characterized in that: In step b, the concentration of the formaldehyde aqueous solution is 35-40wt%.

7. The method for preparing a composite desulfurizing agent for waste gas treatment according to claim 3, characterized in that: In step b, the mass volume ratio of the 3-methoxypropylamine to the formaldehyde aqueous solution is 1 g: (1.3-1.5) mL.

8. A composite desulfurizing agent for waste gas treatment prepared by the preparation method according to any one of claims 1 to 7.

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