Method for recovering sulfur from thiophanate-methyl tail gas

Abstract

The invention belongs to the technical field of sulfur recovery, and provides a method for recovering sulfur from thiophanate-methyl tail gas, the preparation method comprises the following steps: step 1, adding a complexing agent, an iron source and a stabilizer into deionized water, adjusting the pH value to 7.0-7.5, heating to 40-50 DEG C, and stirring to react for 3-5 hours to obtain a desulfurization catalyst; 2, sulfur-containing tail gas generated in the thiophanate-methyl production process is introduced into a combustion furnace to be combusted, and hydrogen sulfide gas is obtained; 3, the hydrogen sulfide gas is introduced into a desulfurization reactor containing a desulfurization catalyst for a removal reaction, the removed gas enters a liquid filter for gas-liquid-solid separation, and purified gas and a solid solution are obtained; 4, the solid solution enters a sedimentation reactor, sulfur in the solid solution is enriched through sedimentation, then filter pressing is conducted, and recovery liquid and sulfur are obtained. The method is high in tail gas desulfurization efficiency, capable of producing high-purity sulfur, simple in operation, low in energy consumption and suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of sulfur recovery, and particularly relates to a method for recovering sulfur from thiophanate-methyl tail gas. Background Art

[0002] Thiophanate-methyl, also known as thiophanate-methyl (abbreviated as "thiophanate-methyl"), is a benzimidazole fungicide. It is a broad-spectrum, systemic, low-toxic fungicide with systemic, preventive, and therapeutic effects. Thiophanate-methyl works by rapidly being absorbed by crops when sprayed on them. Within the plant, it undergoes a series of biochemical reactions to transform into carbendazim, disrupting the cell division of pathogens and preventing their normal growth, achieving a bactericidal effect. Therefore, it is widely used to control diseases of cereals, vegetables, fruit trees, and other economic crops.

[0003] However, since the raw materials used in the production process of methyl thiophanate contain a small amount of sulfide, the sulfide reacts with hydrochloric acid during the reaction process to produce hydrogen sulfide gas. In the existing technology, liquid alkali is generally used to destroy the hydrogen sulfide gas before it is transported to the exhaust gas treatment device. However, this treatment process consumes a lot of energy and the effective components in the exhaust gas are greatly lost, resulting in a waste of resources.

[0004] Therefore, developing a method that can efficiently recover sulfur from thiophanate-methyl tail gas and can save energy, increase efficiency and protect the environment is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The object of the present invention is to provide a method for recovering sulfur from thiophanate-methyl tail gas, so as to solve the problem that the sulfur-containing tail gas generated in the production process of thiophanate-methyl is difficult to be recovered and utilized.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for recovering sulfur from thiophanate-methyl tail gas comprises the following steps:

[0008] Step 1: Add a complexing agent, an iron source, and a stabilizer into deionized water, adjust the pH value to 7.0-7.5, and stir the mixture at a temperature of 40-50° C. for 3-5 hours to obtain a desulfurization catalyst;

[0009] Step 2: introducing the sulfur-containing tail gas generated during the production of thiophanate-methyl into a combustion furnace for combustion to obtain hydrogen sulfide gas;

[0010] Step 3: The hydrogen sulfide gas is introduced into the desulfurization reactor containing the desulfurization catalyst obtained in step 1 to undergo a desulfurization reaction. The desulfurized gas enters a filtrator for gas-liquid-solid separation to obtain purified gas and a solid solution.

[0011] Step 4: The solid solution enters a sedimentation reactor, and the sulfur in the solid solution is enriched by sedimentation, followed by filter pressing to obtain a recovered liquid and sulfur.

[0012] In some possible implementations, the weight ratio of the complexing agent, the iron source, and the stabilizer in step 1 is 2-5:1-3:0.1-0.5.

[0013] In some possible implementations, the complexing agent in step 1 is at least one of polyaspartic acid and iminodisuccinic acid. Polyaspartic acid and iminodisuccinic acid are used as complexing agents because they have strong complexing capabilities and produce water and carbon dioxide as degradation products, making them environmentally friendly and non-polluting. Furthermore, the desulfurization catalyst prepared further has advantages such as a high hydrogen sulfide removal rate and a high regeneration rate.

[0014] In some possible implementations, the iron source in step 1 is a soluble iron salt, and the soluble iron salt is at least one of ferric nitrate, ferric chloride, ferric sulfate, ferrous carbonate, ferric carbonate and ferrous oxide.

[0015] In some possible implementations, the stabilizer in step 1 is at least one of sodium dodecyl sulfate, maltose, and sodium p-toluenesulfonate.

[0016] In some possible implementations, the temperature in the desulfurization reactor in step 3 is 30-100° C., and the pressure is 0.1-3.0 MPa.

[0017] In some possible implementations, step 4 includes adding a sulfur sedimentation agent to the sedimentation reactor; the amount of the sulfur sedimentation agent is 3-5% of the weight of the solid solution.

[0018] In some possible implementations, the sulfur precipitator comprises the following raw materials by weight: 25-30 parts fatty alcohol polyoxyethylene ether, 1.0-3.0 parts flocculant, and 6-8 parts wetting agent. Adding the sulfur precipitator effectively increases the size of sulfur particles in the system, thereby reducing suspended sulfur content and alleviating sulfur blockage.

[0019] In some possible implementations, the flocculant is at least one of polyacrylamide and sodium polyacrylate.

[0020] In some possible implementations, the wetting agent is at least one of glycerol, propylene glycol, and polyethylene glycol.

[0021] Beneficial effects of the present invention:

[0022] The desulfurization catalyst used in the present invention is composed of a complexing agent, an iron source, a stabilizer, and water. It has very strong catalytic oxidation performance and can not only effectively convert hydrogen sulfide into elemental sulfur, greatly improving the removal rate of hydrogen sulfide; it can also enhance the utilization rate of oxygen during the regeneration process, accelerate the air oxidation of the complexed ferrous iron in the desulfurization catalyst, reduce the amount of air used, and increase the regeneration rate. At the same time, the desulfurization catalyst provided by the present invention has a low Fe ion loss rate and good stability during the desulfurization process, and can also effectively avoid problems such as corrosion of desulfurization equipment and desulfurization wastewater treatment.

[0023] The method for recovering sulfur from thiophanate-methyl tail gas provided by the present invention has high desulfurization efficiency of the tail gas, reduces the sulfide content in the tail gas to below 20 ppm, and can produce high-purity sulfur; and is simple to operate, has low energy consumption, and is suitable for industrial production. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0025] Obviously, the following descriptions are merely some examples or embodiments of the present application. Those skilled in the art can apply the present application to other similar scenarios without inventive effort. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in the present application, changes in design, manufacturing, or production based on the technical content disclosed in the present application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in the present application.

[0026] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters or repeated descriptions of substantially identical structures may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to facilitate a thorough understanding of this application by those skilled in the art and is not intended to limit the subject matter recited in the claims.

[0027] Example 1

[0028] This embodiment provides a method for recovering sulfur from thiophanate-methyl tail gas, and the specific preparation steps are as follows:

[0029] Step 1: Weigh 2 parts of polyaspartic acid, 1 part of ferric nitrate, and 0.1 part of sodium dodecyl sulfate in deionized water, adjust the pH value to 7.0 with aqueous ammonia (25% by mass), and stir the mixture at 40° C. for 4.5 hours to obtain a desulfurization catalyst;

[0030] Step 2: introducing the sulfur-containing tail gas generated during the production of thiophanate-methyl into a combustion furnace for combustion to obtain hydrogen sulfide gas;

[0031] Step 3: The hydrogen sulfide gas is introduced into the desulfurization reactor containing the desulfurization catalyst obtained in step 1 for removal reaction. The temperature in the desulfurization reactor is 30° C. and the pressure is 0.1 MPa. The removed gas enters the filtrator for gas-liquid-solid separation to obtain purified gas and solid solution.

[0032] Step 4: The solid solution enters a sedimentation reactor, wherein a sulfur precipitant having a weight percentage of 3% of the solid solution is added. The sulfur in the solid solution is enriched by sedimentation, and then filtered to obtain a recovered liquid and sulfur.

[0033] The sulfur precipitant used above comprises the following raw materials in parts by weight:

[0034] 25 parts of fatty alcohol polyoxyethylene ether, 1.0 part of polyacrylamide and 6 parts of glycerol.

[0035] Example 2

[0036] This embodiment provides a method for recovering sulfur from thiophanate-methyl tail gas, and the specific preparation steps are as follows:

[0037] Step 1: Weigh 5 parts of polyaspartic acid, 3 parts of ferric nitrate, and 0.5 parts of sodium lauryl sulfate in deionized water, adjust the pH value to 7.0 with aqueous ammonia (25% by mass), and stir the mixture at 40° C. for 4.5 hours to obtain a desulfurization catalyst;

[0038] Step 2: introducing the sulfur-containing tail gas generated during the production of thiophanate-methyl into a combustion furnace for combustion to obtain hydrogen sulfide gas;

[0039] Step 3: The hydrogen sulfide gas is introduced into the desulfurization reactor containing the desulfurization catalyst obtained in step 1 for removal reaction. The temperature in the desulfurization reactor is 30° C. and the pressure is 0.1 MPa. The removed gas enters the filtrator for gas-liquid-solid separation to obtain purified gas and solid solution.

[0040] Step 4: The solid solution enters a sedimentation reactor, wherein a sulfur precipitant having a weight percentage of 3% of the solid solution is added. The sulfur in the solid solution is enriched by sedimentation, and then filtered to obtain a recovered liquid and sulfur.

[0041] The sulfur precipitant used above comprises the following raw materials in parts by weight:

[0042] 25 parts of fatty alcohol polyoxyethylene ether, 1.0 part of polyacrylamide and 6 parts of glycerol.

[0043] Example 3

[0044] This embodiment provides a method for recovering sulfur from thiophanate-methyl tail gas, and the specific preparation steps are as follows:

[0045] Step 1: Weigh 2 parts of polyaspartic acid, 1 part of ferric nitrate, and 0.1 part of sodium dodecyl sulfate in deionized water, adjust the pH value to 7.0 with aqueous ammonia (25% by mass), and stir the mixture at 40° C. for 4.5 hours to obtain a desulfurization catalyst;

[0046] Step 2: introducing the sulfur-containing tail gas generated during the production of thiophanate-methyl into a combustion furnace for combustion to obtain hydrogen sulfide gas;

[0047] Step 3: The hydrogen sulfide gas is introduced into the desulfurization reactor containing the desulfurization catalyst obtained in step 1 for removal reaction. The temperature in the desulfurization reactor is 90° C. and the pressure is 0.5 MPa. The removed gas enters the filtrator for gas-liquid-solid separation to obtain purified gas and solid solution.

[0048] Step 4: The solid solution enters a sedimentation reactor, wherein a sulfur precipitant having a weight percentage of 3% of the solid solution is added. The sulfur in the solid solution is enriched by sedimentation, and then filtered to obtain a recovered liquid and sulfur.

[0049] The sulfur precipitant used above comprises the following raw materials in parts by weight:

[0050] 25 parts of fatty alcohol polyoxyethylene ether, 1.0 part of polyacrylamide and 6 parts of glycerol.

[0051] Example 4

[0052] This embodiment provides a method for recovering sulfur from thiophanate-methyl tail gas, and the specific preparation steps are as follows:

[0053] Step 1: Weigh 2 parts of polyaspartic acid, 1 part of ferric nitrate, and 0.1 part of sodium dodecyl sulfate in deionized water, adjust the pH value to 7.0 with aqueous ammonia (25% by mass), and stir the mixture at 40° C. for 4.5 hours to obtain a desulfurization catalyst;

[0054] Step 2: introducing the sulfur-containing tail gas generated during the production of thiophanate-methyl into a combustion furnace for combustion to obtain hydrogen sulfide gas;

[0055] Step 3: The hydrogen sulfide gas is introduced into the desulfurization reactor containing the desulfurization catalyst obtained in step 1 for removal reaction. The temperature in the desulfurization reactor is 30° C. and the pressure is 0.1 MPa. The removed gas enters the filtrator for gas-liquid-solid separation to obtain purified gas and solid solution.

[0056] Step 4: The solid solution enters a sedimentation reactor, wherein a sulfur precipitant having a solid solution weight of 5% is added. The sulfur in the solid solution is enriched by sedimentation, and then filtered to obtain a recovered liquid and sulfur.

[0057] The sulfur precipitant used above comprises the following raw materials in parts by weight:

[0058] 25 parts of fatty alcohol polyoxyethylene ether, 1.0 part of polyacrylamide and 6 parts of glycerol.

[0059] Example 5

[0060] This embodiment provides a method for recovering sulfur from thiophanate-methyl tail gas, and the specific preparation steps are as follows:

[0061] Step 1: Weigh 2 parts of polyaspartic acid, 1 part of ferric nitrate, and 0.1 part of sodium dodecyl sulfate in deionized water, adjust the pH value to 7.0 with aqueous ammonia (25% by mass), and stir the mixture at 40° C. for 4.5 hours to obtain a desulfurization catalyst;

[0062] Step 2: introducing the sulfur-containing tail gas generated during the production of thiophanate-methyl into a combustion furnace for combustion to obtain hydrogen sulfide gas;

[0063] Step 3: The hydrogen sulfide gas is introduced into the desulfurization reactor containing the desulfurization catalyst obtained in step 1 for removal reaction. The temperature in the desulfurization reactor is 30° C. and the pressure is 0.1 MPa. The removed gas enters the filtrator for gas-liquid-solid separation to obtain purified gas and solid solution.

[0064] Step 4: The solid solution enters a sedimentation reactor, wherein a sulfur precipitant having a weight percentage of 3% of the solid solution is added. The sulfur in the solid solution is enriched by sedimentation, and then filtered to obtain a recovered liquid and sulfur.

[0065] The sulfur precipitant used above comprises the following raw materials in parts by weight:

[0066] 30 parts of fatty alcohol polyoxyethylene ether, 3.0 parts of polyacrylamide and 8 parts of glycerol.

[0067] Example 6

[0068] This embodiment provides a method for recovering sulfur from thiophanate-methyl tail gas, and the specific preparation steps are as follows:

[0069] Step 1: Weigh 4 parts of polyaspartic acid, 2 parts of ferric nitrate, and 0.4 parts of sodium lauryl sulfate in deionized water, adjust the pH value to 7.0 with aqueous ammonia (25% by mass), and stir the mixture at 40° C. for 4.5 hours to obtain a desulfurization catalyst;

[0070] Step 2: introducing the sulfur-containing tail gas generated during the production of thiophanate-methyl into a combustion furnace for combustion to obtain hydrogen sulfide gas;

[0071] Step 3: The hydrogen sulfide gas is introduced into the desulfurization reactor containing the desulfurization catalyst obtained in step 1 for removal reaction. The temperature in the desulfurization reactor is 50° C. and the pressure is 2 MPa. The gas after removal enters the filtrator for gas-liquid-solid separation to obtain purified gas and solid solution.

[0072] Step 4: The solid solution enters a sedimentation reactor, wherein a sulfur precipitant having a solid solution weight of 4% is added, and the sulfur in the solid solution is enriched by sedimentation, and then filtered to obtain a recovered liquid and sulfur.

[0073] The sulfur precipitant used above comprises the following raw materials in parts by weight:

[0074] 28 parts of fatty alcohol polyoxyethylene ether, 2.0 parts of polyacrylamide and 7 parts of glycerol.

[0075] Comparative Example 1

[0076] Compared with embodiment 1, the only difference is the preparation of the desulfurization catalyst in step 1:

[0077] Step 1: Weigh by weight, add 1 part of polyaspartic acid, 0.5 parts of ferric nitrate and 0.1 parts of sodium dodecyl sulfate into deionized water, adjust the pH value to 7.0 with ammonia water (mass fraction 25%), heat and stir at 40° C. for 4.5 hours to obtain a desulfurization catalyst.

[0078] Comparative Example 2

[0079] Compared with embodiment 1, the only difference is the temperature and pressure of the desulfurization reactor in step 3:

[0080] Step 3: The hydrogen sulfide gas is introduced into the desulfurization reactor containing the desulfurization catalyst obtained in step 1 for removal reaction. The temperature in the desulfurization reactor is 20°C and the pressure is 0.05 MPa. The removed gas enters the filtrator for gas-liquid-solid separation to obtain purified gas and solid solution.

[0081] Comparative Example 3

[0082] Compared with embodiment 1, the only difference is the amount of sulfur precipitant in step 4:

[0083] Step 4: The solid solution enters a sedimentation reactor, wherein a sulfur precipitant having a solid solution weight of 1.5% is added. The sulfur in the solid solution is enriched by sedimentation, and then filtered to obtain a recovered liquid and sulfur.

[0084] Comparative Example 4

[0085] Compared with embodiment 1, the only difference is the amount of sulfur precipitant raw material used in step 4:

[0086] The sulfur precipitant used includes the following raw materials in parts by weight:

[0087] 20 parts of fatty alcohol polyoxyethylene ether, 0.8 parts of polyacrylamide and 6 parts of glycerol.

[0088] Comparative Example 5

[0089] Compared with implementation 1, the only difference is that no sulfur precipitant is added in step 4:

[0090] Step 4: The solid solution enters a sedimentation reactor, and the sulfur in the solid solution is enriched by sedimentation, followed by filter pressing to obtain a recovered liquid and sulfur.

[0091] Application tests were conducted on Examples 1 to 6 and Comparative Examples 1 to 5: the concentration of hydrogen sulfide in the thiophanate-methyl tail gas used in the Examples and Comparative Examples of the present invention was 1030 ppm, the thiophanate-methyl tail gas flow rate was 50 L / min, and the desulfurization catalyst flow rate was 15 L / min; the hydrogen sulfide content (ppm) in the purified gas and the purity of sulfur (the purity was determined according to GB / T 2449-2006 "Industrial Sulfur") were detected. The test results are shown in Table 1:

[0092] Table 1

[0093]

[0094]

[0095] As can be seen from Table 1, the method for recovering sulfur from thiophanate-methyl tail gas provided in the present invention has a high hydrogen sulfide removal rate, reducing the sulfide content in the tail gas to below 20 ppm, and can produce high-purity sulfur. At the same time, the operation is simple, the energy consumption is low, and it is suitable for industrial production.

[0096] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements inherent to such process, method, article or device. It should be understood that in various embodiments of the present application, the size of the sequence number of each process does not mean the order of execution, some or all of the steps can be executed in parallel or in sequence, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation regulations of this application.

[0097] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0098] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution, and all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0099] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for recovering sulfur from thiophanate-methyl tail gas, characterized in that: The following steps are involved: Step 1: Add a complexing agent, an iron source, and a stabilizer into deionized water, adjust the pH value to 7.0-7.5, and stir the mixture at a temperature of 40-50° C. for 3-5 hours to obtain a desulfurization catalyst; Step 2: introducing the sulfur-containing tail gas generated during the production of thiophanate-methyl into a combustion furnace for combustion to obtain hydrogen sulfide gas; Step 3: The hydrogen sulfide gas is introduced into the desulfurization reactor containing the desulfurization catalyst obtained in step 1 to undergo a desulfurization reaction. The desulfurized gas enters a filtrator for gas-liquid-solid separation to obtain purified gas and a solid solution. Step 4: The solid solution enters a sedimentation reactor, and the sulfur in the solid solution is enriched by sedimentation, followed by filter pressing to obtain a recovered liquid and sulfur.

2. The method for recovering sulfur from thiophanate-methyl tail gas according to claim 1, wherein: In step 1, the weight ratio of the complexing agent, the iron source and the stabilizer is 2-5:1-3:0.1-0.

5.

3. The method for recovering sulfur from thiophanate-methyl tail gas according to claim 1, wherein: The complexing agent in step 1 is at least one of polyaspartic acid and iminodisuccinic acid.

4. The method for recovering sulfur from thiophanate-methyl tail gas according to claim 1, wherein: The iron source in step 1 is a soluble iron salt, and the soluble iron salt is at least one of ferric nitrate, ferric chloride, ferric sulfate, ferrous carbonate, ferric carbonate and ferrous oxide.

5. The method for recovering sulfur from thiophanate-methyl tail gas according to claim 1, characterized in that: The stabilizer in step 1 is at least one of sodium lauryl sulfate, maltose and sodium p-toluenesulfonate.

6. The method for recovering sulfur from thiophanate-methyl tail gas according to claim 1, characterized in that: In step 3, the temperature in the desulfurization reactor is 30-100° C. and the pressure is 0.1-3.0 MPa.

7. The method for recovering sulfur from thiophanate-methyl tail gas according to claim 1, characterized in that: In step 4, a sulfur sedimentation agent is added to the sedimentation reactor; the amount of the sulfur sedimentation agent is 3-5% of the weight of the solid solution.

8. The method for recovering sulfur from thiophanate-methyl tail gas according to claim 1, characterized in that: The sulfur precipitation agent comprises the following raw materials in parts by weight: 25-30 parts of fatty alcohol polyoxyethylene ether, 1.0-3.0 parts of flocculant and 6-8 parts of wetting agent.

9. The method for recovering sulfur from thiophanate-methyl tail gas according to claim 8, characterized in that: The flocculant is at least one of polyacrylamide and sodium polyacrylate.

10. The method for recovering sulfur from thiophanate-methyl tail gas according to claim 8, characterized in that: The wetting agent is at least one of glycerol, propylene glycol and polyethylene glycol.

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