A method for preparing an ionic composite desulfurizer

Abstract

The present invention belongs to the technical field of gas purification, and specifically relates to a method for preparing an ionic composite desulfurizer. In the present invention, liquid A prepared by reacting tri(3,6-dioxaheptyl)amine containing a tertiary amine structure and an ether structure with methoxyacetic acid and solution B prepared by reacting 1,1,3,3-tetramethylguanidine with acrylic acid are used together as the main absorbent of the composite desulfurizer, which effectively improves the selective absorbency and desulfurization efficiency of the composite desulfurizer, and an activator composed of benzalkonium chloride, alkyl dimethyl benzyl ammonium chloride and phosphoric acid is added during the preparation process of the ionic composite desulfurizer, which can not only improve the desulfurization efficiency of the composite desulfurizer, but also improve the thermal stability of the composite desulfurizer.

Description

Technical Field

[0001] The invention belongs to the technical field of gas purification, and in particular relates to a method for preparing an ionic composite desulfurizing agent. Background Art

[0002] Industrial gases such as natural gas, synthesis gas, and oil refinery gas usually contain hydrogen sulfide and organic sulfides. Organic sulfides mainly include carbonyl sulfide, sulfur disulfide, and mercaptans and sulfides with different carbon numbers. These various organic / inorganic sulfide components are not only prone to corrosion of equipment and pipelines during mining, processing, transportation, and use, but also cause environmental pollution when used as fuel. Therefore, they must be purified to meet subsequent utilization requirements.

[0003] Flue gas desulfurization technology mainly uses various alkaline absorbents or adsorbents to capture sulfur dioxide in flue gas and convert it into relatively stable and easily mechanically separated sulfur compounds or elemental sulfur, thereby achieving the purpose of desulfurization. Flue gas desulfurization is currently the most effective and main technical means to control sulfur dioxide pollution. According to whether there is water involved in the desulfurization process and the dry and wet state of the desulfurization product, it can be divided into wet, semi-dry and dry flue gas desulfurization. The basic principle of these desulfurization technologies is to use alkaline substances as absorbents for sulfur dioxide, that is, desulfurizers. Compared with several other desulfurization processes, wet desulfurization technology is the most widely used and most mature technology in my country. It usually uses liquid absorbents and has the advantages of fast desulfurization speed, high removal efficiency, high additive utilization rate and high desulfurization effect. However, there are problems such as secondary pollution, the absorbent cannot be recycled, and the desulfurizer has low desulfurization efficiency.

[0004] Ionic liquid is an organic salt that is liquid at room temperature or near room temperature, has excellent thermal stability, chemical inertness, and good solubility in many compounds. Using ionic liquids to capture gaseous sulfur has become a development trend in the field of flue gas purification. For example, the Chinese patent application document with publication number CN117717892A discloses a preparation process for a composite desulfurizer for absorbing sulfur dioxide, which includes the following steps: Step 1: Prepare a composite ionic liquid, soak it with a pre-treated and modified rubber material, and then let it stand to obtain a rubber liquid composite; Step 2: Add an auxiliary agent to the rubber liquid composite, stir it, and then mix and disperse it in water to obtain a composite desulfurizer; wherein the rubber material is pre-treated and modified to enhance its load capacity and mechanical properties, and the composite ionic liquid is prepared by compounding the ionic liquid and the polymerized ion, and then acrylamide is added to introduce active groups, and the reaction activity and stability are high. The preparation method of the composite ionic liquid is to disperse N-ethyl-3-methylpyridinium bromide ionic liquid in a mass ratio of 11-15:22-24 in a polymerized ionic liquid, heat it under reflux reaction, add an equal amount of deionized water to mix to obtain a mixed solution, add acrylamide in an amount of 10%-20% of the mass of the mixed solution under stirring conditions, and then adjust the pH to 8-9. However, the chemical action of the particle liquid prepared by this method is too strong, resulting in high energy consumption for absorbent regeneration, low thermal stability, and too high viscosity, resulting in low absorption selectivity. Summary of the invention

[0005] In order to solve the technical problems existing in the related art such as low desulfurization efficiency, low thermal stability, poor selectivity, etc., the object of the present invention is to provide a method for preparing an ionic composite desulfurizer.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] A method for preparing an ionic composite desulfurizer comprises the following steps:

[0008] S1: adding tri(3,6-dioxaheptyl)amine and methoxyacetic acid into a reaction kettle filled with deionized water, stirring and reacting to obtain liquid A;

[0009] S2: adding anhydrous ethanol and 1,1,3,3-tetramethylguanidine to a reaction kettle, and dropping the alcohol solution of acrylic acid in a stirring state and a cold water bath condition, and continuing to stir the reaction after the dropping is completed to obtain liquid B;

[0010] S3: Evenly mix the liquid A obtained in step S1 and the liquid B obtained in step S2, concentrate under vacuum, and cool to obtain a solution C;

[0011] S4: adding a defoamer, an activator and an antioxidant to the solution C obtained in step S3, stirring evenly to obtain an ionic composite desulfurizer.

[0012] In the present invention, liquid A obtained by reacting tri(3,6-dioxaheptyl)amine containing a tertiary amine structure and an ether structure with methoxyacetic acid and solution B obtained by reacting 1,1,3,3-tetramethylguanidine with acrylic acid are used as the main absorbent of the composite desulfurizer. Studies have found that the tertiary amine structure can combine with SO2 to form a charge transfer complex, but does not react with CO2, and can selectively absorb SO2. The ether structure has a good affinity for the physical absorption of SO2. The ionic liquid desulfurizer based on tri(3,6-dioxaheptyl)amine contains both a tertiary amine structure and an ether structure, and has excellent regeneration performance, fast desorption rate, excellent thermal stability and low viscosity. In particular, the rich active absorption sites in the ether-rich ionic liquid can effectively improve the selective absorption of SO2. The ionic liquid containing tetramethylguanidine obtained by reacting 1,1,3,3-tetramethylguanidine with acrylic acid also has a selective absorption effect on SO2, effectively improving the desulfurization efficiency of the composite desulfurizer.

[0013] Furthermore, in the preparation method of the ionic composite desulfurizer, the activator in step S4 is composed of benzalkonium chloride, alkyl dimethyl benzyl ammonium chloride and phosphoric acid in a mass ratio of 7-10:4-9:2-3.

[0014] The present invention adds an activator composed of benzalkonium chloride, alkyl dimethyl benzyl ammonium chloride and phosphoric acid during the preparation process of the ionic composite desulfurizer, which can not only accelerate the desulfurization process and improve the desulfurization efficiency, but also reduce the consumption of the desulfurizer and increase the activity of the desulfurizer. In addition, the solution B prepared by the reaction of 1,1,3,3-tetramethylguanidine and acrylic acid is a colorless and transparent ionic liquid monomer at room temperature, which shows a certain absorption capacity for sulfur dioxide, but has poor thermal stability. When the temperature is higher than 100°C, it shows obvious weight loss, and partial polymerization occurs when absorbing sulfur dioxide. The present invention effectively avoids the polymerization of solution B at high temperature by adding the activator component, and effectively improves the thermal stability of the ionic composite desulfurizer.

[0015] Furthermore, in the preparation method of the ionic composite desulfurizer, the molar ratio of tri(3,6-dioxaheptyl)amine to methoxyacetic acid in step S1 is 1-3:1.

[0016] Furthermore, in the preparation method of the ionic composite desulfurizer, the stirring reaction time in step S1 is 24-28 hours.

[0017] Furthermore, in the step S2 of the preparation method of the ionic composite desulfurizer, the molar ratio of 1,1,3,3-tetramethylguanidine to acrylic acid is 3-5:1-2.

[0018] Furthermore, in the preparation method of the ionic composite desulfurizer, the alcohol solution of acrylic acid in step S2 is an ethanol solution of acrylic acid, and the mass percentage of acrylic acid is 30%-40%.

[0019] Furthermore, in the step S2 of the preparation method of the ionic composite desulfurizer, the time for continuing the stirring reaction is 2-3 hours.

[0020] Furthermore, in the preparation method of the ionic composite desulfurizer, the vacuum concentration in step S3 is carried out at a temperature of 60-70° C. and for a time of 12-14 hours.

[0021] Furthermore, in the step S4 of the method for preparing the ionic composite desulfurizer, the defoaming agent is one of hexadecyltrimethylammonium chloride, dodecyldimethyl tertiary amine and dodecyldimethyl sulfobetaine.

[0022] Furthermore, in step S4 of the method for preparing the ionic composite desulfurizer, the antioxidant is one of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and mercaptoethylamine.

[0023] Compared with the prior art, the preparation method of the ionic composite desulfurizer provided by the present invention has the following technical advantages:

[0024] (1) In the present invention, liquid A prepared by the reaction of tri(3,6-dioxaheptyl)amine containing a tertiary amine structure and an ether structure with methoxyacetic acid and solution B prepared by the reaction of 1,1,3,3-tetramethylguanidine with acrylic acid are used together as the main absorbent of the composite desulfurizer, thereby effectively improving the selective absorbency and desulfurization efficiency of the composite desulfurizer;

[0025] (2) In the preparation process of the ionic composite desulfurizer, the present invention adds an activator composed of benzalkonium chloride, alkyl dimethyl benzyl ammonium chloride and phosphoric acid, which can not only improve the desulfurization efficiency of the composite desulfurizer, but also improve the thermal stability of the composite desulfurizer;

[0026] (3) The preparation method of the ionic composite desulfurizer provided by the present invention is simple, and the raw materials are easily available, which is conducive to industrial production. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. Those skilled in the art can make various modifications based on the basic idea of ​​the present invention, but as long as they do not deviate from the basic idea of ​​the present invention, they are all within the scope of the present invention.

[0028] The tri(3,6-dioxaheptyl)amine in this specific embodiment was purchased from Shanghai Yuanye Biotechnology Co., Ltd., product number: S49963; the methoxyacetic acid was purchased from Hubei Guangao Biotechnology Co., Ltd., product number: GA1729; the 1,1,3,3-tetramethylguanidine was purchased from Shanghai Yuanye Biotechnology Co., Ltd., product number: Y17708; the acrylic acid was purchased from Chengdu Xiya Chemical Co., Ltd., product number: B12963; the hexadecyltrimethylammonium chloride was purchased from Shanghai Jinpan Biotechnology Co., Ltd., product number: 112-02-7; the ethylenediaminetetraacetic acid was purchased from Hubei Guoyun Furui Technology Co., Ltd., Product number: GY138148; the benzalkonium chloride was purchased from Hunan Huibaiyi New Materials Co., Ltd., product number: HBY090; the alkyl dimethyl benzyl ammonium chloride was purchased from Shanghai Xuejie Chemical Co., Ltd., product number: 1227; the phosphoric acid was purchased from Hubei Xinghengye Chemical Co., Ltd.; the triethylamine was purchased from Zibo Mingju Chemical Co., Ltd.; the isomeric C10 ether amine was purchased from Shandong Xingguang Chemical Co., Ltd., product number: GE609; the acetic acid was purchased from Hubei Cuiyuan Biotechnology Co., Ltd., product number: CRN6682; the maleic acid was purchased from Nanjing Chemical Reagent Co., Ltd., product number: F20230000179.

[0029] Example 1

[0030] A method for preparing an ionic composite desulfurizer comprises the following steps:

[0031] S1: Add 1 mol of tri(3,6-dioxaheptyl)amine and 1 mol of methoxyacetic acid into a reactor filled with 50 mL of deionized water, and stir to react for 24 hours to obtain liquid A;

[0032] S2: Add 50 g of anhydrous ethanol and 3 mol of 1,1,3,3-tetramethylguanidine to the reactor, and dropwise add a 30% by mass acrylic acid ethanol solution (1 mol of acrylic acid) under stirring and cold water bath conditions. After the dropwise addition is completed, continue stirring and reacting for 2 hours to obtain Liquid B;

[0033] S3: The liquid A obtained in step S1 and the liquid B obtained in step S2 are mixed evenly, concentrated under vacuum at 60° C. for 12 h, and cooled to obtain a solution C;

[0034] S4: adding hexadecyltrimethylammonium chloride, an activator and ethylenediaminetetraacetic acid to the solution C obtained in step S3, stirring evenly, to obtain an ionic composite desulfurizer; the activator is composed of benzalkonium chloride, alkyl dimethylbenzyl ammonium chloride and phosphoric acid in a mass ratio of 7:4:2.

[0035] Example 2

[0036] A method for preparing an ionic composite desulfurizer comprises the following steps:

[0037] S1: 3 mol of tri(3,6-dioxaheptyl)amine and 1 mol of methoxyacetic acid were added to a reaction kettle filled with 50 mL of deionized water, and the mixture was stirred for 28 h to obtain liquid A;

[0038] S2: Add 50 g of anhydrous ethanol and 5 mol of 1,1,3,3-tetramethylguanidine to the reactor, and dropwise add a 40% by mass acrylic acid ethanol solution (2 mol of acrylic acid) under stirring and cold water bath conditions. After the dropwise addition is completed, continue stirring and reacting for 3 hours to obtain Liquid B;

[0039] S3: The liquid A obtained in step S1 and the liquid B obtained in step S2 are mixed evenly, concentrated under vacuum at 70° C. for 14 h, and cooled to obtain a solution C;

[0040] S4: adding dodecyldimethyl tertiary amine, an activator and diethylenetriaminepentaacetic acid to the solution C obtained in step S3, stirring evenly to obtain an ionic composite desulfurizer; the activator is composed of benzalkonium chloride, alkyldimethylbenzylammonium chloride and phosphoric acid in a mass ratio of 10:9:3.

[0041] Example 3

[0042] A method for preparing an ionic composite desulfurizer comprises the following steps:

[0043] S1: Add 2 mol of tri(3,6-dioxaheptyl)amine and 1 mol of methoxyacetic acid into a reaction kettle filled with 50 mL of deionized water, and stir to react for 26 hours to obtain liquid A;

[0044] S2: Add 50 g of anhydrous ethanol and 4 mol of 1,1,3,3-tetramethylguanidine to the reactor, and dropwise add a 36% by mass acrylic acid ethanol solution (1 mol of acrylic acid) under stirring and cold water bath conditions. After the dropwise addition is completed, continue stirring and reacting for 2.5 hours to obtain Liquid B;

[0045] S3: Liquid A obtained in step S1 and Liquid B obtained in step S2 are mixed evenly, concentrated under vacuum at 65° C. for 13 h, and cooled to obtain Solution C;

[0046] S4: adding dodecyldimethylsulfobetaine, an activator and mercaptoethylamine to the solution C obtained in step S3, stirring evenly to obtain an ionic composite desulfurizer; the activator is composed of benzalkonium chloride, alkyl dimethylbenzyl ammonium chloride and phosphoric acid in a mass ratio of 9:7:2.

[0047] Comparative Example 1

[0048] The preparation method of the composite desulfurizer in this comparative example is similar to that in Example 3. The difference between this comparative example and Example 3 is that an equal amount of triethylamine is used in step S1 of the preparation method of the composite desulfurizer in this comparative example instead of tri(3,6-dioxaheptyl)amine.

[0049] Comparative Example 2

[0050] The preparation method of the composite desulfurizer in this comparative example is similar to that in Example 3. The difference between this comparative example and Example 3 is that in step S1 of the preparation method of the composite desulfurizer in this comparative example, an equal amount of isomeric C10 etheramine is used instead of tri(3,6-dioxaheptyl)amine.

[0051] Comparative Example 3

[0052] The preparation method of the composite desulfurizer in this comparative example is similar to that in Example 3. The difference between this comparative example and Example 3 is that an equal amount of acetic acid is used instead of methoxyacetic acid in step S1 of the preparation method of the composite desulfurizer in this comparative example.

[0053] Comparative Example 4

[0054] The preparation method of the composite desulfurizer in this comparative example is similar to that in Example 3. The difference between this comparative example and Example 3 is that in step S2 of the preparation method of the composite desulfurizer in this comparative example, an equal amount of 1,1,3,3-tetramethylguanidine is used to replace the alcohol solution of acrylic acid.

[0055] Comparative Example 5

[0056] The preparation method of the composite desulfurizer in this comparative example is similar to that in Example 3. The difference between this comparative example and Example 3 is that an equal amount of maleic acid is used instead of acrylic acid in step S2 of the preparation method of the composite desulfurizer in this comparative example.

[0057] Comparative Example 6

[0058] The preparation method of the composite desulfurizer in this comparative example is similar to that in Example 3. The difference between this comparative example and Example 3 is that an equal amount of benzalkonium chloride is used in the activator of the composite desulfurizer in this comparative example instead of phosphoric acid.

[0059] Comparative Example 7

[0060] The preparation method of the composite desulfurizer in this comparative example is similar to that in Example 3. The difference between this comparative example and Example 3 is that the activator of the composite desulfurizer in this comparative example consists of benzalkonium chloride, alkyl dimethyl benzyl ammonium chloride and phosphoric acid in a mass ratio of 3:2:8.

[0061] Test example

[0062] In this test example, the desulfurization efficiency of the composite desulfurizer prepared in Example 1 to Example 3 and Comparative Example 1 to Comparative Example 7 will be tested, and the thermal stability of Example 1 to Example 3 and Comparative Example 6 to Comparative Example 7 will be tested. The test process is as follows: 60 mL of the composite desulfurizer is placed in a U-shaped glass test tube reactor in a constant temperature water bath, and the water bath temperature is controlled to 25±5°C and 120±5°C respectively. The test gas (including the following molar fraction components: 1% SO2, 3% O2, 25% CO2, and the balance N2) is introduced into the glass test tube reactor at a rate of 30±5 mL / min, and the composition of sulfides in the outlet gas is detected by gas chromatography using a TCD detector. When the concentration of sulfur dioxide in the outlet gas is less than 100 mg / m 3 When the adsorption process is completed, the desulfurization efficiency is calculated as follows: Desulfurization efficiency = (C1-C2) / C1×100%, where C1 is the mole fraction of sulfur dioxide in the inlet gas, and C2 is the mole fraction of sulfur dioxide in the outlet gas. The test results are shown in Table 1.

[0063] Table 1 Desulfurization efficiency test results

[0064]

[0065] As shown in Table 1, the desulfurization efficiency of the ionic composite desulfurizer prepared by the preparation method of the ionic composite desulfurizer provided by the present invention is 98.5%-99.7% at 25±5°C, and the desulfurization efficiency is 97.6%-99.4% at 120±5°C, which indicates that the ionic composite desulfurizer provided by the present invention has good desulfurization performance under both normal temperature and high temperature conditions. Among them, the desulfurization efficiency of the ionic composite desulfurizer prepared in Example 3 is the highest, which is the best embodiment of the present invention.

[0066] Compared with Example 3, Comparative Example 1 uses an equal amount of triethylamine instead of tri(3,6-dioxaheptyl)amine, but the desulfurization efficiency of the prepared composite desulfurizer is reduced, which indicates that the ether structure has a good affinity for the physical absorption of SO2; Comparative Example 2 uses an equal amount of isomeric C10 etheramine instead of tri(3,6-dioxaheptyl)amine, but the desulfurization efficiency of the prepared composite desulfurizer is reduced, which indicates that the tertiary amine structure can combine with SO2 to form a charge transfer complex and selectively absorb SO2; Comparative Example 3 uses an equal amount of acetic acid instead of methoxyacetic acid, and Comparative Example 5 uses an equal amount of maleic acid instead of acrylic acid, but the desulfurization efficiency of the prepared composite desulfurizer is reduced, which indicates that in the preparation process of ionic liquids, not all organic acids can The technical effects of methoxyacetic acid and acrylic acid are achieved; in comparative example 4, an equal amount of 1,1,3,3-tetramethylguanidine is used to replace the alcohol solution of acrylic acid, but the desulfurization efficiency of the obtained composite desulfurizer is reduced, which indicates that the ionic liquid containing tetramethylguanidine obtained by the reaction of 1,1,3,3-tetramethylguanidine and acrylic acid also has a selective absorption effect on SO2, effectively improving the desulfurization efficiency of the composite desulfurizer; in comparative examples 6 and 7, the components and ratios of the activator are changed, but the desulfurization efficiencies of the obtained composite desulfurizer at both room temperature and high temperature are reduced, which indicates that the components and ratios of the activator provided by the present invention are the key to improving the desulfurization efficiency of the composite desulfurizer, and the components and ratios of the activator will affect the desulfurization efficiency of the composite desulfurizer under high temperature conditions.

[0067] The above embodiments are merely illustrative of the preparation method of the present invention, and are not intended to limit the present invention. Any person skilled in the art may not modify the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the technical concept provided by the present invention are still covered by the claims of the present invention.

Claims

1. A method for preparing an ionic composite desulfurizer, characterized in that: The following steps are involved: S1: adding tri(3,6-dioxaheptyl)amine and methoxyacetic acid into a reaction kettle filled with deionized water, stirring and reacting to obtain liquid A; S2: adding anhydrous ethanol and 1,1,3,3-tetramethylguanidine to a reaction kettle, and dropping the alcohol solution of acrylic acid under stirring and cold water bath conditions, and continuing to stir the reaction after the dropping is completed to obtain liquid B; S3: Evenly mix the liquid A obtained in step S1 and the liquid B obtained in step S2, concentrate under vacuum, and cool to obtain a solution C; S4: adding a defoamer, an activator and an antioxidant to the solution C obtained in step S3, stirring evenly to obtain an ionic composite desulfurizer; The vacuum concentration temperature is 60-70°C and the time is 12-14h; The activator is composed of benzalkonium chloride, alkyl dimethyl benzyl ammonium chloride and phosphoric acid in a mass ratio of 7-10:4-9:2-3.

2. The method for preparing the ionic composite desulfurizer according to claim 1, characterized in that: The molar ratio of tri(3,6-dioxaheptyl)amine to methoxyacetic acid in step S1 is 1-3:

1.

3. The method for preparing the ionic composite desulfurizing agent according to claim 1, characterized in that: The stirring reaction time in step S1 is 24-28 hours.

4. The method for preparing the ionic composite desulfurizing agent according to claim 1, characterized in that: The molar ratio of 1,1,3,3-tetramethylguanidine to acrylic acid in step S2 is 3-5:1-2.

5. The method for preparing the ionic composite desulfurizing agent according to claim 1, characterized in that: The alcohol solution of acrylic acid in step S2 is an ethanol solution of acrylic acid, and the mass percentage of acrylic acid is 30%-40%.

6. The method for preparing the ionic composite desulfurizing agent according to claim 1, characterized in that: The stirring reaction time in step S2 is 2-3 hours.

7. The method for preparing the ionic composite desulfurizing agent according to claim 1, characterized in that: The defoaming agent in step S4 is one of hexadecyltrimethylammonium chloride, dodecyldimethyl tertiary amine and dodecyldimethyl sulfobetaine.

8. The method for preparing the ionic composite desulfurizing agent according to claim 1, characterized in that: The antioxidant in step S4 is one of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and mercaptoethylamine.

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