Preparation process of amine liquid purification resin for desulfurization system

Abstract

The present invention belongs to the technical field of ion exchange resins, and particularly relates to a preparation process of an amine solution purification resin for a desulfurization system. In the present invention, the amine solution purification resin for the desulfurization system is prepared by suspension polymerization. By adding polar third monomers such as acrylic acid and methyl methacrylate to the polymerization system of styrene and a cross-linking agent, the structure of the resin is changed, so as to achieve the purpose of regulating the polarity, pore size and adsorption performance of the resin. In addition, acrylic acid and methyl acrylate are added to the polymer monomers of the amine solution purification resin in the present invention, effectively improving the hydrophilic property of the amine solution purification resin, and enabling the prepared polymer product to have good anti-pollution performance. The amine solution purification resin prepared by using the preparation process of the amine solution purification resin provided by the present invention has the characteristics of large exchange capacity, rich pore structure, strong activity, good adsorption performance and strong anti-pollution ability.

Description

Technical Field

[0001] The present invention belongs to the technical field of ion exchange resins, and particularly relates to a preparation process of amine liquid purification resin for a desulfurization system. Background Art

[0002] Natural gas, coke oven gas, gasoline, petroleum liquefied gas, etc. usually use an alkanolamine absorption device to remove acidic gases such as H2S and CO2 in the gas stream. The acidic gases dissolve in the amine liquid to form soluble alkanolamine salts. Then, water, slightly reacted alkanolamine, and the alkanolamine salt solution enter the stripping tower for heating. The alkanolamine salt decomposes to release acidic gases such as H2S and CO2, and the alkanolamine solution is recycled into the absorption tower again to realize the recycling of the alkanolamine solution. However, in addition to acidic gases such as H2S and CO2 in the gas stream, there are also acidic gases such as SO2, CS2, and COS. The alkanolamine salts formed after these gases react with the alkanolamine solution cannot be removed by the stripping tower, will remain in the alkanolamine solution, and accumulate continuously, resulting in a decline in the quality of the amine liquid. As the alkanolamine solution is recycled, the desulfurization and decarbonization ability of the alkanolamine solution is reduced.

[0003] Currently, the amine liquid deep purification and regeneration technologies adopted include the caustic distillation method, the electrodialysis method, and the ion exchange method. The caustic distillation method is to add liquid caustic in the amine liquid to displace the alkanolamine salt into free amine, and then recover the amine by distillation. The electrodialysis method is to use direct current and a selective ion permeable membrane to achieve the purpose of desalting, so as to purify the amine liquid. These two methods have high energy consumption; the ion exchange method has become the mainstream in the amine liquid deep purification and regeneration technology due to its low energy consumption, high amine liquid recovery rate, etc. However, the type, pore size, and ion exchange capacity of the resin in the ion exchange resin all affect the purification effect of the amine liquid and the resin life, etc. Moreover, the strongly basic anion exchange resin is easily contaminated and has a short resin life, resulting in a high treatment cost of the amine liquid.

[0004] The Chinese patent application document with the publication number CN116984035A discloses a preparation method of an ion exchange resin for an amine liquid purification device, specifically: using styrene, divinylbenzene, benzoyl peroxide, gelatin, methylene blue, sodium chloride, chloromethyl ether, methylal, polyethylene glycol, and trimethylamine as the main raw materials, and the preparation path is: synthesizing a cross-linked polymer by suspension polymerization of styrene and divinylbenzene, chloromethylation reaction of the styrene and divinylbenzene cross-linked polymer, and amination reaction of the chloromethylated styrene and divinylbenzene cross-linked polymer. The resin particles prepared by this method have a smaller particle size and a shorter preparation time, but the removal efficiency of the heat-stable salts in the alkanolamine solution needs to be verified.

[0005] The Chinese patent application document with the publication number CN119281407A discloses a modified anion exchange resin for removing amine liquid heat stable salts and its preparation method, specifically as follows: (1) cleaning the anion exchange resin with deionized water; (2) activating the resin cleaned in step (1) with an acid solution or an alkali solution; (3) refluxing and reacting the resin activated in step (2) with a hydrophobic silane coupling agent in an anhydrous solvent, and then cleaning with deionized water after the reaction; (4) reacting the resin treated in step (3) with an organic acid, and then cleaning with deionized water after the reaction; (5) reacting the resin treated in step (4) with a vinyl compound containing a sulfonic acid group in a solvent, and then cleaning with deionized water after the reaction. Summary of the Invention

[0006] In order to solve the technical problems existing in the related art, such as the purification resin being easily contaminated, having a low adsorption capacity, and a low removal efficiency, the purpose of the present invention is to provide a preparation process for an amine liquid purification resin for a desulfurization system.

[0007] In order to achieve the above purpose, the technical solution of the present invention is as follows:

[0008] A preparation process for an amine liquid purification resin for a desulfurization system includes the following steps:

[0009] S1: Mix styrene, a crosslinking agent, acrylic acid, and methyl methacrylate evenly, add an initiator, stir evenly, then add a pore-forming agent, and continue to stir evenly to obtain an oil phase;

[0010] S2: Add deionized water, carboxymethyl cellulose, and sodium dodecyl sulfate to a reaction kettle, heat to 50 - 60 °C under stirring, add the oil phase prepared in step S1, introduce nitrogen, raise the temperature to 85 - 90 °C, keep the temperature for reaction, continue to raise the temperature to 95 - 100 °C, react until the resin is formed, cool, filter, and wash to obtain spherical resin;

[0011] S3: Put the spherical resin prepared in step S2 into a Soxhlet extractor for extraction, then take it out, dry it, and sieve it to obtain an amine liquid purification resin for a desulfurization system.

[0012] In the present invention, an amine liquid purification resin for a desulfurization system is prepared by suspension polymerization. By adding polar third monomers such as acrylic acid and methyl methacrylate to the polymerization system of styrene and a crosslinking agent, the structure of the resin is changed, thereby achieving the purpose of regulating the polarity, pore size, and adsorption performance of the resin. In addition, acrylic acid and methyl acrylate are added to the polymer monomers of the amine liquid purification resin in the present invention, effectively improving the hydrophilic performance of the amine liquid purification resin and endowing the prepared polymer product with good anti-pollution performance. A crosslinking agent is added during the polymerization process in the present invention to crosslink the prepared polymer product into a spherical shape, effectively increasing the pore structure of the polymer product and improving the adsorption capacity. Adding a pore-forming agent can form a rich porous structure in the polymer product, effectively solving the technical problem of the low adsorption capacity of existing purification resins.

[0013] Further, the mass parts of the styrene and methyl methacrylate in step S1 are as follows: 20 - 30 parts of styrene, 7 - 10 parts of acrylic acid, and 15 - 20 parts of methyl methacrylate.

[0014] Further, the crosslinking agent in step S1 is composed of acryloyl triazine and divinyl pyridine in a mass ratio of 3 - 5:7 - 9, and the mass parts of the crosslinking agent are 5 - 8 parts.

[0015] In the present invention, acryloyl triazine and divinyl pyridine are selected to jointly form a crosslinking agent, which can form crosslinks between the polymer chains, make the polymer product spherical, improve the strength of the polymer, and control the crosslinking degree of the polymer product by controlling the mass ratio of acryloyl triazine and divinyl pyridine, thereby controlling the adsorption capacity of the polymer product.

[0016] Even further, the crosslinking agent in step S1 is composed of acryloyl triazine and divinyl pyridine in a mass ratio of 3:8, and the mass parts of the crosslinking agent are 7 parts.

[0017] Further, the initiator in step S1 is benzoyl peroxide, and the mass parts of the initiator are 2 - 4 parts.

[0018] Further, the pore-forming agent in step S1 is composed of polyethylene glycol, n-octanol, and undecanol in a mass ratio of 12 - 15:7 - 11:4 - 8, and the mass parts of the pore-forming agent are 9 - 13 parts.

[0019] In the present invention, a pore-forming agent is added to the oil phase, so that during the polymerization process, a pore structure is formed in the polymer product through physical or chemical action. By selecting the type and dosage of the pore-forming agent, the pore size and specific surface area in the polymer product are precisely controlled, the adsorption capacity of the amine solution purification resin is increased, and the removal efficiency of the amine solution purification resin is effectively improved. Among them, polyethylene glycol can adsorb the surrounding solvent molecules during the polymerization process to form a stable micelle structure. As the solvent is removed, a porous structure is formed in the polymer product; n-octanol can promote the formation of pores and improve the mechanical strength of the material, and undecanol can further regulate the pore size and improve the adsorption capacity of the polymer product.

[0020] Furthermore, the pore-forming agent in step S1 is composed of polyethylene glycol, n-octanol and undecanol in a mass ratio of 13:9:6, and the mass fraction of the pore-forming agent is 10 parts.

[0021] Further, the mass fractions of the deionized water, sodium carboxymethyl cellulose and sodium dodecyl sulfate in step S2 are: 100-120 parts of deionized water, 0.5-1 part of sodium carboxymethyl cellulose, and 5-7 parts of sodium dodecyl sulfate.

[0022] Further, the stirring speed in the stirring state in step S2 is 250-300 rpm, the time of the heat preservation reaction is 2.2-2.5 h, and the heating rate of the continuous heating is 5-7 °C / h.

[0023] Further, the extraction time in step S3 is 8-10 h, and the sieving is through a 60-mesh sieve.

[0024] Compared with the prior art, the preparation process of the amine solution purification resin for a desulfurization system provided by the present invention has the following technical advantages:

[0025] (1) The amine solution purification resin prepared by using the preparation process of the amine solution purification resin provided by the present invention has the characteristics of large exchange capacity, strong activity, strong anti-pollution ability, etc.;

[0026] (2) The amine solution purification resin prepared by using the preparation process of the amine solution purification resin provided by the present invention has good adsorption performance, a rich multi-stage porous structure, and a large specific surface area;

[0027] (3) The preparation process of the amine solution purification resin for a desulfurization system provided by the present invention is simple, the raw materials are available, and it is conducive to realizing industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a scanning electron microscope image of the amine solution purification resin for a desulfurization system prepared in Example 3 at 100 μm;

[0029] Figure 2SEM image of the amine liquid purification resin for desulfurization system prepared in Example 3 at a scale of 1μm. Detailed implementation manners

[0030] 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 according to the basic idea of the present invention, but as long as they do not depart from the basic idea of the present invention, they are all within the scope of the present invention.

[0031] Example 1

[0032] A preparation process of an amine liquid purification resin for a desulfurization system includes the following steps:

[0033] S1: Mix 20 g of styrene, 5 g of crosslinking agent, 7 g of acrylic acid, and 15 g of methyl methacrylate evenly, add 2 g of benzoyl peroxide, stir evenly, then add 9 g of porogen, and continue to stir evenly to obtain an oil phase; the crosslinking agent is composed of acryloyl triazine and divinylpyridine in a mass ratio of 3:7; the porogen is composed of polyethylene glycol, n-octanol, and undecanol in a mass ratio of 12:7:4;

[0034] S2: Add 120 g of deionized water, 0.5 g of carboxymethyl cellulose, and 5 g of sodium dodecyl sulfate to a reaction kettle, heat to 50 °C under stirring at a speed of 250 rpm, add the oil phase prepared in step S1, introduce nitrogen, raise the temperature to 85 °C, keep the temperature for reaction for 2.2 h, continue to raise the temperature to 95 °C at a rate of 5 °C / h, react until the resin is formed, cool, filter, and wash to obtain spherical resin;

[0035] S3: Put the spherical resin prepared in step S2 into a Soxhlet extractor for extraction for 8 h, then take it out and dry it, and pass through a 60-mesh sieve to obtain the amine liquid purification resin for the desulfurization system.

[0036] Example 2

[0037] A preparation process of an amine liquid purification resin for a desulfurization system includes the following steps:

[0038] S1: Mix 30 g of styrene, 8 g of crosslinking agent, 10 g of acrylic acid, and 20 g of methyl methacrylate evenly, add 4 g of benzoyl peroxide, stir evenly, then add 13 g of porogen, and continue to stir evenly to obtain an oil phase; the crosslinking agent is composed of acryloyl triazine and divinylpyridine in a mass ratio of 5:9; the porogen is composed of polyethylene glycol, n-octanol, and undecanol in a mass ratio of 15:11:8;

[0039] S2: Add 100 g of deionized water, 1 g of carboxymethyl cellulose, and 7 g of sodium dodecyl sulfate into the reaction kettle. Heat it to 60 °C under stirring at a speed of 300 rpm. Add the oil phase prepared in step S1, introduce nitrogen gas, heat up to 90 °C, keep the temperature for reaction for 2.5 h, continue to heat up to 100 °C at a rate of 7 °C / h, react until the resin is formed, cool it, filter it, and wash it to obtain spherical resin;

[0040] S3: Put the spherical resin prepared in step S2 into a Soxhlet extractor for extraction for 10 h, then take it out and dry it, and pass it through a 60-mesh sieve to obtain the amine liquid purification resin for the desulfurization system.

[0041] Example 3

[0042] A preparation process of amine liquid purification resin for a desulfurization system, comprising the following steps:

[0043] S1: Mix 26 g of styrene, 7 g of crosslinking agent, 9 g of acrylic acid, and 17 g of methyl methacrylate evenly, add 3 g of benzoyl peroxide, stir evenly, then add 10 g of pore-forming agent, and continue to stir evenly to obtain an oil phase; the crosslinking agent is composed of acryloyl triazine and divinyl pyridine according to a mass ratio of 3:8; the pore-forming agent is composed of polyethylene glycol, n-octanol, and undecanol according to a mass ratio of 13:9:6;

[0044] S2: Add 115 g of deionized water, 0.7 g of carboxymethyl cellulose, and 8 g of sodium dodecyl sulfate into the reaction kettle. Heat it to 57 °C under stirring at a speed of 280 rpm. Add the oil phase prepared in step S1, introduce nitrogen gas, heat up to 88 °C, keep the temperature for reaction for 2.4 h, continue to heat up to 98 °C at a rate of 6 °C / h, react until the resin is formed, cool it, filter it, and wash it to obtain spherical resin;

[0045] S3: Put the spherical resin prepared in step S2 into a Soxhlet extractor for extraction for 9 h, then take it out and dry it, and pass it through a 60-mesh sieve to obtain the amine liquid purification resin for the desulfurization system.

[0046] Comparative Example 1

[0047] The preparation process of the amine liquid purification resin in this comparative example is similar to that of Example 3. The difference between this comparative example and Example 3 is that in this comparative example, an equal amount of styrene is used to replace methyl acrylate.

[0048] Comparative Example 2

[0049] The preparation process of the amine liquid purification resin in this comparative example is similar to that of Example 3. The difference between this comparative example and Example 3 is that the crosslinking agent used in this comparative example is divinylbenzene.

[0050] Comparative Example 3

[0051] The preparation process of the amine liquid purification resin described in this comparative example is similar to that of Example 3. The difference between this comparative example and Example 3 is that all the cross-linking agents used in this comparative example are divinylpyridine.

[0052] Comparative Example 4

[0053] The preparation process of the amine liquid purification resin described in this comparative example is similar to that of Example 3. The difference between this comparative example and Example 3 is that the cross-linking agent used in this comparative example is composed of acryloyl triazine and divinylpyridine in a mass ratio of 10:3.

[0054] Comparative Example 5

[0055] The preparation process of the amine liquid purification resin described in this comparative example is similar to that of Example 3. The difference between this comparative example and Example 3 is that all the pore-forming agents used in this comparative example are polyethylene glycol.

[0056] Comparative Example 6

[0057] The preparation process of the amine liquid purification resin described in this comparative example is similar to that of Example 3. The difference between this comparative example and Example 3 is that all the pore-forming agents used in this comparative example are n-octanol.

[0058] Comparative Example 7

[0059] The preparation process of the amine liquid purification resin described in this comparative example is similar to that of Example 3. The difference between this comparative example and Example 3 is that the pore-forming agent used in this comparative example is composed of polyethylene glycol, n-octanol and undecanol in a mass ratio of 2:5:11.

[0060] Test Example

[0061] After the amine liquid purification resins prepared in Examples 1 - 3 and Comparative Examples 2 - 7 were fully dried in a vacuum drying oven, the pore volume, pore diameter and specific surface area of the resins were measured by the nitrogen adsorption - desorption method using a Tristar 3000 full-automatic specific surface area and porosity analyzer. The relative pressure during the measurement was 0.0 - 1.0 (P / P0). The test results are shown in Table 1.

[0062] The microscopic morphology of the amine liquid purification resin prepared in Example 3 was observed using a scanning electron microscope (scanning electron microscopy, SEM; ZEISS Sigma 300). The test results are shown in Figure 1 and Figure 2 .

[0063] Select the desulfurized amine liquid from the catalytic unit of a refinery (appearance: light yellow and transparent, heat-stable salt content: about 3.5%) to conduct an anti-pollution ability test on the amine liquid purification resins prepared in Example 3 and Comparative Example 1. Specifically: Take 10 mL of the test resin to purify the amine liquid, with the amine liquid dosage being 30 L, and observe the attenuation of the working exchange capacity of the two resins. The test results are shown in Table 2.

[0064] Table 1 Test Results of Pore Volume, Pore Diameter and Specific Surface Area

[0065]

[0066] As can be seen from Table 1, the pore volume of the amine liquid purification resin prepared by the production process of the amine liquid purification resin for the desulfurization system provided by the present invention is 1.28 - 1.75 cm 3 / g, the pore diameter is 11.85 - 12.64 nm, and the specific surface area is 350.33 - 367.89 m 2 / g, which fully shows that the amine liquid purification resin provided by the present invention has good adsorption capacity and can improve the removal efficiency of the amine liquid. Among them, the performance of the amine liquid purification resin prepared in Example 3 is the best, which is the best embodiment of the present invention.

[0067] Compared with Example 3, the cross-linking agent used in Comparative Example 2 is divinylbenzene, but the pore volume of the prepared amine liquid purification resin decreases, the pore diameter increases, and the specific surface area decreases. This shows that although divinylbenzene can copolymerize with monomers such as styrene and methyl methacrylate to make the polymer chains form an interconnected network structure, its cross-linking density and cross-linking uniformity are poor, resulting in a decrease in the pore volume of the amine liquid purification resin and an increase in the pore diameter and specific surface area; in Comparative Examples 3 and 4, the types and dosage ratios of the cross-linking agents are changed respectively, but they all have different degrees of influence on the pore volume, pore diameter and specific surface area of the amine liquid purification resin. This shows that the components and dosage of the cross-linking agent in the present invention have been optimized, and changing the cross-linking agent components or mass ratio will lead to poor cross-linking of the polymer and a decrease in the adsorption capacity; in Comparative Examples 5 - 7, the types and dosage ratios of the pore-forming agents are changed respectively, but they all have different degrees of influence on the pore volume, pore diameter and specific surface area of the amine liquid purification resin. This shows that the pore-forming agent has a key influence on the amine liquid purification resin. Using the pore-forming agent within the scope of the present invention is beneficial to generate macropores that play a role in diffusion channels inside the resin, and the pore structure is uniform, effectively improving the pore volume, pore diameter and specific surface area of the amine liquid purification resin. Among them, the pore diameter of the amine liquid purification resin prepared in Example 5 is significantly reduced, which shows that polyethylene glycol is more conducive to forming micropores and increasing the number of pore structures.

[0068] From Figure 1 and Figure 2It can be seen that the amine liquid purification resin prepared by the production process of the amine liquid purification resin for the desulfurization system provided by the present invention is spherical in structure and has a complex porous structure, which can effectively improve the adsorption capacity and removal efficiency.

[0069] Table 2 Test results of anti-pollution performance

[0070]

[0071] As can be seen from Table 2, the initial working exchange capacity of the amine liquid purification resin prepared in Example 3 is 0.75 mol / L, and the working exchange capacity after 200 purification cycles is 0.61 mol / L, which fully demonstrates its good anti-pollution performance. In Comparative Example 1, an equal amount of styrene was used to replace methyl acrylate, but the working exchange capacity of the prepared amine liquid purification resin decreased significantly after work, which indicates that the addition of acrylic acid and methyl acrylate in the polymer monomer of the amine liquid purification resin of the present invention effectively improves the hydrophilic property of the amine liquid purification resin, making the prepared polymer product have good anti-pollution performance.

[0072] The above embodiments only illustrate the preparation method of the present invention by way of example, and do not limit the present invention. Any person skilled in this technology in the art shall not modify the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the technical idea provided by the present invention are still covered by the claims of the present invention.

Claims

1. A process for preparing an amine solution purification resin for a desulfurization system, characterized in that: The following steps are involved: S1: Styrene, crosslinking agent, acrylic acid and methyl methacrylate are mixed evenly, an initiator is added, porogen is added after stirring evenly, and the mixture is stirred evenly to obtain an oil phase; S2: Add deionized water, carboxymethyl cellulose and sodium dodecyl sulfate to the reaction kettle, heat to 50-60°C while stirring, add the oil phase obtained in step S1, introduce nitrogen, heat to 85-90°C, keep the temperature for reaction, continue to heat to 95-100°C, react until the resin is formed, cool, filter, wash, and obtain spherical resin; S3: putting the spherical resin obtained in step S2 into a Soxhlet extractor for extraction, then taking it out, drying it, and sieving it to obtain an amine solution purification resin for a desulfurization system; The cross-linking agent in step S1 is composed of acryloyl triazine and divinyl pyridine in a mass ratio of 3-5:7-9; the porogen is composed of polyethylene glycol, n-octanol and undecanol in a mass ratio of 12-15:7-11:4-8; the mass proportions of styrene, acrylic acid and methyl methacrylate in step S1 are: 20-30 parts of styrene, 7-10 parts of acrylic acid, and 15-20 parts of methyl methacrylate.

2. The preparation process of the amine liquid purification resin for desulfurization system according to claim 1, characterized in that: The mass fraction of the cross-linking agent in step S1 is 5-8 parts.

3. The process for preparing the amine solution purification resin for desulfurization system according to claim 1, characterized in that: In step S1, the cross-linking agent is composed of acryloyl triazine and divinyl pyridine in a mass ratio of 3:8, and the mass fraction of the cross-linking agent is 7 parts.

4. The preparation process of the amine liquid purification resin for desulfurization system according to claim 1, characterized in that: The initiator in step S1 is benzoyl peroxide, and the mass fraction of the initiator is 2-4 parts.

5. The preparation process of the amine liquid purification resin for desulfurization system according to claim 1, characterized in that: The mass fraction of the porogen in step S1 is 9-13 parts.

6. The process for preparing the amine solution purification resin for desulfurization system according to claim 1, characterized in that: The porogen in step S1 is composed of polyethylene glycol, n-octanol and undecanol in a mass ratio of 13:9:6, and the mass fraction of the porogen is 10 parts.

7. The process for preparing the amine solution purification resin for desulfurization system according to claim 1, characterized in that: The mass proportions of the deionized water, carboxymethyl cellulose and sodium dodecyl sulfate in step S2 are: 100-120 parts of deionized water, 0.5-1 parts of sodium carboxymethyl cellulose, and 5-7 parts of sodium dodecyl sulfate.

8. The process for preparing the amine solution purification resin for desulfurization system according to claim 1, characterized in that: The stirring speed of the stirring state in step S2 is 250-300 rpm, the insulation reaction time is 2.2-2.5 h, and the heating rate of the continued heating is 5-7° C. / h.

9. The process for preparing the amine solution purification resin for desulfurization system according to claim 1, characterized in that: The extraction time in step S3 is 8-10 hours, and the sieving is through a 60-mesh sieve.

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