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, and relates to the technical field of desulfurizers. In order to improve the treatment of sulfur-containing gas in waste gas and avoid the problem of decreased desulfurization performance of some desulfurizers at high temperatures, the invention modifies triazine desulfurizers. 3-Hydroxypropylamine is used as a raw material, reacted with ethanetricarboxylic acid, and an intermediate containing a three-arm amino structure is obtained. On this basis, the invention further mixes the intermediate with 3-methoxypropylamine containing a methoxy group and an amino group to prepare a modified triazine desulfurizer with a triazine ring structure. The high molecular weight and the addition of nitrogen are utilized to increase the molecular stability, so that the desulfurizer finally prepared still has excellent desulfurization ability at high temperatures, avoids the defect of poor desulfurization efficiency of high-temperature waste gas, and reduces pollution to the environment.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurizers, in particular to a composite desulfurizer 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 of pipelines, reactors, furnaces and other important equipment, shortening the service life of equipment, increasing maintenance costs, and even leading to 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 pollution of the atmosphere, soil and water sources. 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 purpose of the present invention is to provide a composite desulfurizer 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 object, the present invention provides the following technical solution: a method for preparing a composite desulfurizer for waste gas treatment, comprising the following steps: 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, mixing them again for 30-120 minutes, adding sodium hydroxide, stirring them uniformly, and discharging the mixture 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:

[0007] a. Under nitrogen atmosphere, 3-hydroxypropylamine and di-tert-butyl dicarbonate were added to tetrahydrofuran, stirred at 20-35 ° C for 1-2h, ethanetricarboxylic acid was added thereto, the temperature was raised to 45-66 ° C, stirred, and refluxed for 12-24h. After removing excess solvent by rotary evaporation, the resulting product was dispersed in hydrochloric acid solution, stirred at room temperature for 5-8h, heated to 68-75 ° 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 108-110 ° C, kept warm for 10-15min, and cooled to room temperature to obtain an intermediate;

[0008] b. Add the intermediate and 3-methoxypropylamine to tetrahydrofuran, stir and mix thoroughly, protect under nitrogen atmosphere, raise the temperature to 55-65°C, and add formaldehyde aqueous solution dropwise for 2-4 hours. After the addition is completed, continue stirring and react for 0.5-1 hour, and then remove excess solvent by rotary evaporation to obtain a modified triazine desulfurizer.

[0009] 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.

[0010] Furthermore, in step b, the mass ratio of the intermediate to 3-methoxypropylamine is 1:(1.2-1.4) in parts by weight.

[0011] Furthermore, in step b, the concentration of the formaldehyde aqueous solution is 35-40 wt%.

[0012] 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.

[0013] Furthermore, a composite desulfurizer for waste gas treatment is prepared by the above method.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] In order to improve the treatment of sulfur-containing gases 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 current exhaust gas emissions, due to the different types of exhaust gases, high-temperature gases often occur. At high temperatures, some desulfurizers will experience a problem of reduced desulfurization performance, thereby increasing the sulfur content in the exhaust gas and causing unqualified pollution emissions.

[0016] Therefore, the present invention carries out a modification treatment on triazine desulfurizers; the present invention first uses 3-hydroxypropylamine as a raw material, reacts it with an amino protective agent di-tert-butyl dicarbonate to protect the amino group therein, then reacts it with ethanetricarboxylic acid again, releases the amino group under an acidic environment, removes di-tert-butyl dicarbonate by high-temperature evaporation, and then heats the product again to remove hydrogen chloride impurities in the product, thereby preparing an intermediate containing a three-arm amino structure;

[0017] On this basis, the present invention further mixes it with 3-methoxypropylamine containing methoxy and amino structures, and then reacts it with formaldehyde again to prepare a modified triazine desulfurizer with a triazine ring structure using an amine-aldehyde condensation method. 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 increase the molecular stability. As a result, the desulfurizer finally prepared still has excellent desulfurization ability at high temperatures, avoiding the defect of poor desulfurization efficiency of high-temperature exhaust gas and reducing pollution to the environment. DETAILED DESCRIPTION

[0018] 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.

[0019] Example 1. A method for preparing a composite desulfurizer for waste gas treatment, comprising the following steps:

[0020] 30 parts of a modified triazine desulfurizer and 18 parts of tetrahydrothiophene were mixed by weight, and a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto. After stirring and dispersing the mixture uniformly, 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 the mixture was stirred uniformly before discharging to obtain a composite desulfurizer for waste gas treatment.

[0021] The preparation method of the modified triazine desulfurizer comprises the following steps:

[0022] a. Under nitrogen atmosphere, 1 part of 3-hydroxypropylamine and 2.7 parts of di-tert-butyl dicarbonate were added to tetrahydrofuran by weight, and stirred at 30 ° C for 1 hour. Then, 0.65 parts of ethanetricarboxylic acid were added thereto, and the temperature was raised to 60 ° C, stirred, and refluxed in the dark for 12 hours. After removing the excess solvent by rotary evaporation, the resulting product was dispersed in hydrochloric acid solution, stirred at room temperature for 8 hours, and then heated to 72-75 ° C. The reaction was stirred until di-tert-butyl dicarbonate evaporated, and the excess solvent was removed by rotary evaporation. The dried product was collected, heated to 110 ° C under nitrogen atmosphere, kept warm for 15 minutes, and cooled to room temperature to obtain an intermediate;

[0023] b. In parts by weight, 1 part of the intermediate and 1.2 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed, and then heated to 60 ° C under a nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was stirred for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer;

[0024] 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.

[0025] Example 2. A method for preparing a composite desulfurizer for waste gas treatment, comprising the following steps:

[0026] Compared with Example 1, this example increases the amount of modified triazine desulfurizer added to the composite desulfurizer for waste gas treatment;

[0027] After mixing 45 parts of a 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. 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 exhaust gas treatment;

[0028] The preparation method of the modified triazine desulfurizer comprises the following steps:

[0029] a. Under nitrogen atmosphere, 1 part of 3-hydroxypropylamine and 2.7 parts of di-tert-butyl dicarbonate were added to tetrahydrofuran by weight, and stirred at 30 ° C for 1 hour. Then, 0.65 parts of ethanetricarboxylic acid were added thereto, and the temperature was raised to 60 ° C, stirred, and refluxed in the dark for 12 hours. After removing the excess solvent by rotary evaporation, the resulting product was dispersed in hydrochloric acid solution, stirred at room temperature for 8 hours, and then heated to 72-75 ° C. The reaction was stirred until di-tert-butyl dicarbonate evaporated, and the excess solvent was removed by rotary evaporation. The dried product was collected, heated to 110 ° C under nitrogen atmosphere, kept warm for 15 minutes, and cooled to room temperature to obtain an intermediate;

[0030] b. In parts by weight, 1 part of the intermediate and 1.2 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed, and then heated to 60 ° C under a nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was stirred for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer;

[0031] 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.

[0032] Example 3. A method for preparing a composite desulfurizer for waste gas treatment, comprising the following steps:

[0033] Compared with Example 1, this example increases the amount of di-tert-butyl dicarbonate added in step a;

[0034] 30 parts of a modified triazine desulfurizer and 18 parts of tetrahydrothiophene were mixed by weight, and a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto. After stirring and dispersing the mixture uniformly, 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 the mixture was stirred uniformly before discharging to obtain a composite desulfurizer for waste gas treatment.

[0035] The preparation method of the modified triazine desulfurizer comprises the following steps:

[0036] a. Under nitrogen atmosphere, 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, and then 0.65 parts of ethanetricarboxylic acid were added thereto, the temperature was raised to 60 ° C, stirred, and refluxed in the dark for 12 hours. After removing the excess solvent by rotary evaporation, the resulting product was dispersed in hydrochloric acid solution, stirred at room temperature for 8 hours, heated to 72-75 ° C, stirred and reacted 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 cooled to room temperature to obtain an intermediate;

[0037] b. In parts by weight, 1 part of the intermediate and 1.2 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed, and then heated to 60 ° C under a nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was stirred for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer;

[0038] 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.

[0039] Example 4. A method for preparing a composite desulfurizer for waste gas treatment, comprising the following steps:

[0040] Compared with Example 3, this example increases the amount of ethanetricarboxylic acid added in step a;

[0041] 30 parts of a modified triazine desulfurizer and 18 parts of tetrahydrothiophene were mixed by weight, and a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto. After stirring and dispersing the mixture uniformly, 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 the mixture was stirred uniformly before discharging to obtain a composite desulfurizer for waste gas treatment.

[0042] The preparation method of the modified triazine desulfurizer comprises the following steps:

[0043] a. Under nitrogen atmosphere, 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, and then 0.75 parts of ethanetricarboxylic acid were added thereto, the temperature was raised to 60 ° C, stirred, and refluxed in the dark for 12 hours. After removing the excess solvent by rotary evaporation, the resulting product was dispersed in hydrochloric acid solution, stirred at room temperature for 8 hours, heated to 72-75 ° C, stirred and reacted 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 cooled to room temperature to obtain an intermediate;

[0044] b. In parts by weight, 1 part of the intermediate and 1.2 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed, and then heated to 60 ° C under a nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was stirred for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer;

[0045] 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.

[0046] Example 5. A method for preparing a composite desulfurizer for waste gas treatment, comprising the following steps:

[0047] Compared with Example 4, this example increases the amount of 3-methoxypropylamine added in step b;

[0048] 30 parts of a modified triazine desulfurizer and 18 parts of tetrahydrothiophene were mixed by weight, and a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto. After stirring and dispersing the mixture uniformly, 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 the mixture was stirred uniformly before discharging to obtain a composite desulfurizer for waste gas treatment.

[0049] The preparation method of the modified triazine desulfurizer comprises the following steps:

[0050] a. Under nitrogen atmosphere, 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, and then 0.75 parts of ethanetricarboxylic acid were added thereto, the temperature was raised to 60 ° C, stirred, and refluxed in the dark for 12 hours. After removing the excess solvent by rotary evaporation, the resulting product was dispersed in hydrochloric acid solution, stirred at room temperature for 8 hours, heated to 72-75 ° C, stirred and reacted 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 cooled to room temperature to obtain an intermediate;

[0051] b. In parts by weight, 1 part of the intermediate and 1.4 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed, and then heated to 60 ° C under a nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was stirred for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer;

[0052] 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.

[0053] Example 6. A method for preparing a composite desulfurizer for waste gas treatment, comprising the following steps:

[0054] Compared with Example 5, this embodiment increases the amount of modified triazine desulfurizer added to the composite desulfurizer for waste gas treatment;

[0055] 30 parts of a modified triazine desulfurizer and 18 parts of tetrahydrothiophene were mixed by weight, and a mixed solvent consisting of 12 parts of methyldiethanolamine and 8 parts of ethylenediamine was added thereto. After stirring and dispersing the mixture uniformly, 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 the mixture was stirred uniformly before discharging to obtain a composite desulfurizer for waste gas treatment.

[0056] The preparation method of the modified triazine desulfurizer comprises the following steps:

[0057] a. Under nitrogen atmosphere, 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, and then 0.75 parts of ethanetricarboxylic acid were added thereto, the temperature was raised to 60 ° C, stirred, and refluxed in the dark for 12 hours. After removing the excess solvent by rotary evaporation, the resulting product was dispersed in hydrochloric acid solution, stirred at room temperature for 8 hours, heated to 72-75 ° C, stirred and reacted 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 cooled to room temperature to obtain an intermediate;

[0058] b. In parts by weight, 1 part of the intermediate and 1.4 parts of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed, and then heated to 60 ° C under a nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was stirred for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified triazine desulfurizer;

[0059] 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.

[0060] Comparative Example 1. A method for preparing a composite desulfurizer for waste gas treatment, comprising the following steps:

[0061] Compared with Example 1, this comparative example did not undergo step a treatment;

[0062] 30 parts of the modified desulfurizer 1 and 18 parts of tetrahydrothiophene were mixed by weight, 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.

[0063] The preparation method of the modified desulfurizer 1 comprises the following steps:

[0064] b. 1.2 parts by weight of 3-methoxypropylamine were added to tetrahydrofuran, stirred and mixed, and then heated to 60 ° C under a nitrogen atmosphere. A formaldehyde solution was added dropwise for 2 hours. After the addition was completed, the reaction was stirred for 1 hour, and the excess solvent was removed by rotary evaporation to obtain a modified desulfurizer 1;

[0065] 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.

[0066] Comparative Example 2. A method for preparing a composite desulfurizer for waste gas treatment, comprising the following steps:

[0067] Compared with Example 1, this comparative example did not undergo step b.

[0068] 30 parts of modified desulfurizer 2 and 18 parts of tetrahydrothiophene were mixed by weight, 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.

[0069] The preparation method of the modified desulfurizer 2 comprises the following steps:

[0070] a. Under nitrogen atmosphere, 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 in the dark for 12 hours. The excess solvent was removed by rotary evaporation, and the resulting product was dispersed in hydrochloric acid solution. After stirring at room temperature for 8 hours, the temperature was raised to 72-75°C, and the reaction was stirred 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 modified desulfurizer 2.

[0071] Comparative Example 3. A method for preparing a composite desulfurizing agent for waste gas treatment, comprising the following steps:

[0072] Compared with Example 1, this comparative example uses 1,3,5-tris(2-hydroxyethyl)-hexahydro-s-triazine instead of the modified triazine desulfurizer;

[0073] 30 parts of 1,3,5-tris(2-hydroxyethyl)-hexahydro-s-triazine and 18 parts of tetrahydrothiophene were mixed by weight, 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 the mixture was stirred evenly. Then, the material was discharged to obtain a composite desulfurizer for waste gas treatment.

[0074] Detection: The exhaust 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;

[0075] 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;

[0076] The test results are shown in the table below:

[0077]

[0078] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are 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 will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a composite desulfurizer for waste gas treatment, characterized in that: The following steps are involved: After mixing the modified triazine desulfurizer with tetrahydrothiophene, a mixed solvent consisting of methyldiethanolamine and ethylenediamine is added thereto, and after stirring and dispersing evenly, triethylene glycol and deionized water are added thereto and mixed, and after mixing again for 30-120 minutes, sodium hydroxide is added thereto, and after stirring evenly, the material is 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, 3-hydroxypropylamine and di-tert-butyl dicarbonate were added to tetrahydrofuran, stirred at 20-35 ° C for 1-2h, ethanetricarboxylic acid was added thereto, the temperature was raised to 45-66 ° C, stirred, and refluxed for 12-24h. After removing excess solvent by rotary evaporation, the resulting product was dispersed in hydrochloric acid solution, stirred at room temperature for 5-8h, heated to 68-75 ° 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 108-110 ° C, 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 thoroughly, protect under nitrogen atmosphere, raise the temperature to 55-65°C, and add formaldehyde aqueous solution dropwise for 2-4 hours. After the addition is completed, continue stirring and react for 0.5-1 hour, and then remove excess solvent by rotary evaporation to obtain a modified triazine desulfurizer.

2. The method for preparing a composite desulfurizer for waste gas treatment according to claim 1, characterized in that: 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.

3. The method for preparing a composite desulfurizer for waste gas treatment according to claim 1, 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.

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

5. The method for preparing a composite desulfurizer for waste gas treatment according to claim 1, characterized in that: In step b, the concentration of the formaldehyde aqueous solution is 35-40wt%.

6. The method for preparing a composite desulfurizer for waste gas treatment according to claim 1, 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.

7. A composite desulfurizer for waste gas treatment prepared by the preparation method according to any one of claims 1 to 6.

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