A carbonate-repelling heat-stable salt selective removal agent and a preparation method thereof

Abstract

The application discloses a kind of carbonate-repellent thermally stable salt selective removal agent and preparation method thereof, it is related to the field of thermally stable salt selective removal, solve the problem that active agent in amine solution is removed while removing thermally stable salt in prior art, comprising the following steps: preparation first microspheres;Add reagent 1 and catalyst, after mixing, add first microspheres, react to obtain second microspheres;Add reagent 2 and organic solvent, after mixing, add second microspheres, after reaction, add concentrated hydrochloric acid ethanol solution and react again, obtain third microspheres;Add reagent 4 and reagent 5 to third microspheres, finally add hydrogen peroxide, after reaction, filter out fourth microspheres, after washing, dry, obtain carbonate-repellent thermally stable salt selective removal agent;The remover of the application can release MDEA bound by thermally stable salt anion, make it from MDEAH + Positive ion is restored into MDEA molecule with desulfurization capacity, and active agent-potassium carbonate for strengthening H2S, COS absorption can be retained in amine solution, so as to realize the goal of restoring the desulfurization performance of deteriorated amine solution.

Description

Technical Field

[0001] This invention relates to the field of polymer functional materials technology, and more specifically to the field of selective removal technology of thermally stable salts. Background Technology

[0002] The amine process is a primary method for desulfurization and decarbonization of natural gas, refinery gas, and other industrial acid gases. Among these, methyl diethanolamine (MDEA) has seen rapid development since its introduction in the 1980s due to its significant energy-saving effects. From the 1990s to the present, the development trend has been to add activators or compound organic solvents to MDEA to create different types of formulated amine solvents, tailored to the specific gas quality conditions and purification requirements of acid gases. For example, a hydrogenated tail gas deep desulfurization formulated amine solvent, designed for ultra-low SO2 emissions from natural gas purification plants and refinery tail gases, incorporates potassium carbonate, an activator to enhance the absorption of H2S and COS.

[0003] In the process of purifying tail gas, the formulated amine solution for deep desulfurization of hydrogenated tail gas (hereinafter referred to as amine solution) generates glycolic acid, acetic acid, formic acid, sulfuric acid, oxalic acid, and thiosulfate due to its own oxidation and contamination by tail gas contaminants. These organic and inorganic acids combine with the amine to form heat-stable amine salts, causing this portion of the amine to lose its desulfurization activity, thus reducing the desulfurization performance of the amine solution. Especially when SO2 breakthrough occurs in the unit, a large amount of heat-stable amine salts are generated in the amine solution, leading to a significant decrease in the desulfurization performance of the amine solution and excessive SO2 content in the tail gas. Furthermore, these heat-stable salts are highly corrosive impurities, which can cause corrosion, blockage, and perforation problems in the tail gas desulfurization unit. To ensure that tail gas emissions meet standards and to guarantee the safe and stable operation of the tail gas desulfurization unit, it is essential to remove the heat-stable salts from the amine solution in a timely manner during production.

[0004] US6517700 utilizes electrodialysis to remove heat-stable salts. An electric field causes anions and cations in the amine solution to move towards the anode and cathode, respectively. Anion exchange membranes and cation exchange membranes are then added to selectively allow the anions and cations to pass through, thereby removing them from the amine solution. Potassium carbonate also dissociates into anions and cations under the influence of an electric field, passing through the ion exchange membrane and being removed.

[0005] US5162084 uses a type I styrene-based strong base anion exchange resin to remove heat-stable salts from alkanolamine solutions; US5788864 uses a type II strong base anion exchange resin to remove heat-stable salts from alkanolamine solutions; CN1733355A uses a type I styrene-based strong base anion exchange resin, a type II styrene-based strong base anion exchange resin, and an acrylic-based strong base anion exchange resin to remove heat-stable salts from alkanolamine solutions; CN1230545A uses a macroporous weak base styrene anion exchange resin to remove acidic substances from sulfolane; CN102189008A relates to a novel strong and weak base anion exchange resin and its preparation method. These patents utilize strong or weak base anion exchange resins to remove heat-stable salts. Both strong and weak base anion exchange resins have strong adsorption properties for carbonate ions, so these patents do not selectively adsorb heat-stable salts and potassium carbonate.

[0006] Currently, purification plants using formulated amine solvents can only alleviate production problems caused by excessive heat-stabilized salts by partially replacing the amine solution. This not only fails to restore the desulfurization performance of the unit to its optimal state, but also increases the amount of amine solution used, raising operating costs. Furthermore, the large amount of old amine solution replaced can only be disposed of as waste, generating high waste disposal costs and a large amount of wastewater discharge, placing significant economic and environmental pressure on production units. Therefore, there is an urgent need to develop a selective removal technology for heat-stabilized salts that removes only the harmful heat-stabilized salts from the amine solution without removing the surfactant—potassium carbonate. Summary of the Invention

[0007] The purpose of this invention is to solve the technical problem that existing heat-stable salt removal technologies also remove potassium carbonate, an active agent in hydrogenated tail gas deep desulfurization formulation amine solutions, while removing heat-stable salts, thus worsening the desulfurization performance of the amine solution and causing a decrease in desulfurization performance after amine reactivation. This invention provides a selective heat-stable salt removal agent that excludes carbonates and its preparation method.

[0008] To achieve the above objectives, the present invention specifically adopts the following technical solution: a method for preparing a heat-stable salt selective removal agent that repels carbonates, comprising the following steps:

[0009] Step 1: Add water, dispersant, styrene and crosslinking agent to the first container, turn on the stirrer (stirring speed 600-800 r / min), add initiator, carry out the reaction, and then filter, wash and dry to obtain the first microspheres;

[0010] Step 2: Add reagent 1 and catalyst to the second container, mix well, add the first microsphere to the second container, turn on the stirrer (stirring speed 600-800 r / min), filter, wash and dry after reaction to obtain the second microsphere. Reagent 1 is a mixture of dichloromethyl ether and dichloromethane, and the catalyst is zinc chloride.

[0011] Step 3: Add reagent 2 and organic solvent to the third container, mix well, add the second microsphere, turn on the stirrer (stirring speed 600-800 r / min), after the reaction, add concentrated hydrochloric acid ethanol solution and react for another 0.5-1 hour, then filter, wash and dry to obtain the third microsphere. Reagent 2 includes one or more of hexamethylenetetramine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine.

[0012] Step 4: Add the third microsphere to the fourth container, then add reagent 4 and reagent 5 in sequence, and finally add hydrogen peroxide. Turn on the stirring (stirring speed 600-800 r / min). After the reaction, filter out the fourth microsphere, wash it with sodium hydroxide aqueous solution and dry it to obtain a heat-stable salt selective descrambler that repels carbonates. Reagent 4 is cobalt nitrate and reagent 5 is soluble carbonate.

[0013] In the technical solution of this application, the matrix of the remover is formed by the copolymerization reaction of styrene and crosslinking agent under the action of initiator. The dispersant is added to prevent the particles from agglomerating and sticking together during the polymerization reaction. The ratio of styrene to crosslinking agent and water is determined according to the required micropore size. If the amount of initiator is too large, it will cause violent polymerization, while if it is too small, the polymerization rate will be too slow. If the content of dispersant is too high, it will affect the polymerization reaction. If it is too low, it cannot completely avoid particle sticking. The matrix microspheres that meet the requirements can be prepared according to the ratio, namely the first microsphere. Step 2 is the process of introducing chloromethyl groups on the first microsphere. This step is very slow and a catalyst is needed to speed up the reaction. The reaction conditions and reactants and contents of step 2 are combined to meet the dual requirements of short reaction time and few reaction by-products. Step 3 is the process of introducing amino groups on the chloromethyl groups of the second microsphere. The amino groups introduced in step 3 are easy to react with cobalt nitrate and soluble carbonate, and the product is stable. Hydrogen peroxide plays a catalytic and oxidizing role. If the concentration of hydrogen peroxide is less than 8%, the oxidizing effect is weak and the yield of qualified products is low. If the concentration is too high, the reaction is too violent. The prepared selective desiccant for repelling carbonates is a porous polymer [(Ph-CH2-NH2)]. 3～4 CoCO3] + n [OH - ] n It can both release MDEA bound by thermally stable salt anions, restoring it from MDEAH+ cations back to MDEA molecules with desulfurization capabilities, and retain potassium carbonate, an active agent that enhances the absorption of H2S and COS, in the amine solution, thereby achieving the goal of restoring the desulfurization performance of deteriorated amine solution.

[0014] When the desulfurizing agent of this application comes into contact with an amine solution containing heat-stable salt, it reacts with the heat-stable salt MDEHAHHSS as follows to remove the heat-stable salt anion and restore the MDEHAH+ cation in the heat-stable salt to MDEA molecules with desulfurization capability:

[0015] [(Ph-CH2-NH2) 3～4 CoCO3] + n [OH - ] n + n MDEAH + HSS - →[(Ph-CH2-NH2) 3～4 CoCO3] + n HSS - ] n + n MDEA + n H2O

[0016] The remover in this application contains carbonate groups that repel carbonate ions, so it will not adsorb carbonates.

[0017] Preferably, in step 1, the mass ratio of water, dispersant, styrene, crosslinking agent, and initiator is 300–500: 0.4–0.8: 70–100: 15–22: ​​0.4–0.6; preferably, the mass ratio of water, dispersant, styrene, crosslinking agent, and initiator in step 1 is 400:0.6: 85:18:0.5. If the matrix microspheres are too small, they are prone to pulverization; if they are too large, the resulting remover will have low capacity. Using a mixed dispersant prepared according to the aforementioned proportions can produce matrix microparticles with moderate particle size and narrow particle size distribution, while also shortening the polymerization time.

[0018] More preferably, the dispersant is a mixture of polyvinyl alcohol, methylene blue, and sodium dodecylbenzenesulfonate, with a mass ratio of 50–70: 3–6: 24–47, and more preferably, a mass ratio of 60:4:36; the crosslinking agent is trivinylbenzene; and the initiator is azobisisobutyronitrile. Trivinylbenzene maximizes the number of repeating units in styrene with introduced functional groups, thereby maximizing the capacity of the prepared remover; the polymerization reaction of styrene with trivinylbenzene is relatively slow, and the use of azobisisobutyronitrile can increase the polymerization rate and shorten the preparation time.

[0019] More preferably, the reaction in step 1 specifically includes adding an initiator, heating to 40-50°C, reacting for 1-2 hours, then heating to 80-95°C, and reacting for 7-10 hours.

[0020] Preferably, in step 2, the mass ratio of reagent 1, catalyst, and microspheres is 2-3: 0.3-0.4:1; and the mass ratio of dichloromethyl ether to dichloromethane is 7-8: 3-2.

[0021] Preferably, the reaction temperature in step 2 is 35~50℃ and the reaction time is 7~8 hours.

[0022] Preferably, the mass ratio of reagent 2, organic solvent and third microsphere is 1~2:2~4:1; the organic solvent is one or more of dichloromethane, dichloroethane and chloroform; the volume ratio of concentrated hydrochloric acid to ethanol is 1:2~1:5.

[0023] More preferably, the reaction temperature is 25~40℃ after stirring is started, and the reaction time is 8~10 hours.

[0024] Preferably, the mass ratio of hydrogen peroxide, reagent 4, reagent 5 and the third microsphere is 2~3:0.5~1:0.5~1:1; the concentration of hydrogen peroxide is 8~18%.

[0025] Preferably, the reaction temperature in step 4 is room temperature, and the reaction time is 1 to 3 hours.

[0026] A method for preparing a heat-stable salt selective remover that repels carbonates. The heat-stable salt selective remover that repels carbonates is a porous polymer [(Ph-CH2-NH2)]. 3～ 4CoCO3] + n [OH - ] n

[0027] The beneficial effects of this invention are as follows:

[0028] 1. The prepared selective desiccant for repelling carbonates is a porous polymer [(Ph-CH2-NH2)]. 3～ 4CoCO3] + n [OH - ] n This technology can release MDEA bound by thermally stable salt anions, restoring it from MDEAH+ cations back to MDEA molecules with desulfurization capabilities. It can also retain potassium carbonate, an active agent that enhances the absorption of H2S and COS, in the amine solution, thereby achieving the goal of restoring the desulfurization performance of deteriorated amine solutions. In contrast, existing technologies remove the active agent from the hydrogenated tail gas deep desulfurization formulation of alcohol amine solutions, making their desulfurization performance even worse.

[0029] 2. Selective removal of heat-stable salts is achieved, with a removal rate of ≥95% for heat-stable salts, while ensuring that the co-removal rate of potassium carbonate in the hydrogenation tail gas deep desulfurization formulation amine solution is <1.5%, and the selective adsorption ratio is >63 (selective adsorption ratio = heat-stable salt removal rate / potassium carbonate removal rate). In contrast, existing technologies achieve a co-removal rate of over 90% for potassium carbonate, with a selective adsorption ratio of 1.

[0030] 3. When the desulfurization performance of the hydrogenation tail gas treatment unit is reduced and the tail gas emissions exceed the standard due to the deterioration of the amine liquid, the desulfurization agent of this application can restore the desulfurization performance of the unit to the best state, effectively ensuring the normal production of the gas purification plant and the tail gas emission in compliance with the standard.

[0031] 4. Because it can restore the desulfurization performance of deteriorated amine liquid, it can solve the problem of large consumption of amine liquid and large amount of wastewater discharge caused by the deterioration of amine liquid in gas purification plants, and effectively reduce the production cost and environmental pressure of gas purification plants, resulting in excellent economic and social benefits. Attached Figure Description

[0032] Figure 1 This is a product image of the heat-stable salt selective remover for repelling carbonates prepared in Example 2;

[0033] Figure 2 The image shows the infrared spectrum of the selective desiccant for repelling carbonates prepared in Example 2. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0035] Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] Example 1

[0037] This embodiment provides a method for preparing a heat-stable salt selective removal agent that repels carbonates, comprising the following steps:

[0038] Step 1: Add 300 mL of water, 0.2 g of polyvinyl alcohol, 0.02 g of methylene blue, 0.18 g of sodium dodecylbenzenesulfonate, 70 g of styrene, and 15 g of 1,3,5-trivinylbenzene to the flask equipped with a stirrer. Turn on the stirrer and stir at 600 r / min. Add 0.4 g of azobisisobutyronitrile (AIBN). Heat to 45 °C and react for 1 h. Then heat to 85 °C and continue reacting for 10 h. Filter out the microspheres, wash them, and dry them.

[0039] Step 2: Add 112g of dichloromethyl ether, 48g of dichloromethane, and 24g of zinc chloride to the second container. After mixing, add 80g of the dried microspheres to this container. Turn on the stirrer and stir at a speed of 400 r / min. After heating to 35℃ and reacting for 7 hours, filter out the microspheres, wash them, and dry them.

[0040] Step 3: Add 100g of triethylenetetramine and 200g of dichloromethane to the third container, mix well, then add 100g of the microspheres prepared in the second container to this container, turn on the stirrer, stir at 400 r / min, heat to 36℃ and react for 8h, then add concentrated hydrochloric acid ethanol solution (volume ratio 1:3) and react for 0.6h, then filter out the microspheres, wash and dry them;

[0041] Step 4: Add 120g of the microspheres prepared in the third container to the fourth container, then add 80g of cobalt nitrate and 80g of sodium carbonate in sequence, and finally add 250g of 15% hydrogen peroxide. Turn on the stirrer and stir at a speed of 400 r / min. After reacting for 1 hour, filter out the microspheres, wash them with 5% sodium hydroxide aqueous solution, and dry them to obtain the selective descrambled carbonate repellent.

[0042] Example 2

[0043] like Figure 1-2 As shown in the figure, this embodiment provides a method for preparing a heat-stable salt selective remover that repels carbonates, comprising the following steps:

[0044] Step 1: Add 500 mL of water, 0.42 g of polyvinyl alcohol, 0.04 g of methylene blue, 0.34 g of sodium dodecylbenzenesulfonate, 82 g of styrene, and 20 g of 1,3,5-trivinylbenzene to the flask equipped with a stirrer. Turn on the stirrer and stir at a speed of 750 r / min. Add 0.5 g of azobisisobutyronitrile (AIBN). Heat the mixture to 45 °C and react for 2 h. Then heat the mixture to 85 °C and continue reacting for 8 h. Filter out the microspheres, wash them, and dry them.

[0045] Step 2: Add 147g of dichloromethyl ether, 70g of dichloromethane, and 33g of zinc chloride to the second container. After mixing, add 95g of the dried microspheres to this container. Turn on the stirrer and stir at a speed of 550 r / min. After heating to 50℃ and reacting for 7 hours, filter out the microspheres, wash them, and dry them.

[0046] Step 3: Add 180g of hexamethylenetetramine and 350g of dichloromethane to the third container, mix well, and then add 120g of the microspheres prepared in the second container to this container. Turn on the stirrer and stir at a speed of 550 r / min. Heat to 30℃ and react for 9h. Then add concentrated hydrochloric acid ethanol solution (volume ratio 1:3) and react for 1h. Filter out the microspheres, wash and dry them.

[0047] Step 4: Add 200g of the microspheres prepared in the third container to the fourth container, then add 150g of cobalt nitrate and 150g of sodium carbonate in sequence, and finally add 500g of 15% hydrogen peroxide. Turn on the stirrer and stir at a speed of 550 r / min. After reacting for 1 hour, filter out the microspheres, wash them with 5% sodium hydroxide aqueous solution, and dry them to obtain the selective descrambled carbonate repellent.

[0048] The infrared spectrum of the heat-stable salt selective remover for repelling carbonates prepared in this embodiment is as follows: Figure 2 As shown: Figure 2 The removal agent showed the presence of phenyl (1500cm). -1 1600cm -1 Absorption peaks appear nearby), primary amines (at 3300 cm⁻¹) -1 (Double absorption peaks appear nearby), methylene (2800 cm⁻¹) -1 2900cm -1 (An absorption peak appears nearby), because at 1200 cm⁻¹ -1 The absence of absorption peaks nearby indicates the absence of -CC- groups; the linkage of these groups is Ph-CH2-NH2. The graph also shows the presence of carbonates in the removal agent (700, 730, 860, 1450 cm⁻¹). -1 Absorption peaks appear nearby), hydroxide ions (3600 cm⁻¹) -1 (An absorption peak appears nearby). Electron microscopy and energy dispersive spectroscopy analysis show that the remover contains cobalt, and the ratio of cobalt to nitrogen is 1:(3~4). From the above analysis, it is known that nitrogen in the remover exists in the form of Ph-CH2-NH2, therefore the ratio of cobalt to Ph-CH2-NH2 in the remover is 1:(3~4). When sodium chloride aqueous solution is passed through this remover, the chloride ion content in the solution decreases. The addition of barium chloride does not produce a precipitate, indicating that the ions that exchange chloride ions are OH-. - The external anion of the removing agent is OH. - The carbonate ion exists in the removal agent in the form of cobalt carbonate. Therefore, the molecular formula of the removal agent is:

[0049] [(Ph-CH2-NH2) 3～4 CoCO3] + n [OH - ] n

[0050] The pore volume and pore size of the remover were determined using the nitrogen adsorption method, and the pore volume was 1.4 cm³. 3 / g, average pore size 8.9nm.

[0051] Example 3

[0052] This embodiment provides a method for preparing a heat-stable salt selective removal agent that repels carbonates, comprising the following steps:

[0053] Step 1: Add 300 mL of water, 0.26 g of polyvinyl alcohol, 0.016 g of methylene blue, 0.124 g of sodium dodecylbenzenesulfonate, 70 g of styrene, and 15 g of 1,3,5-trivinylbenzene to the flask equipped with a stirrer. Turn on the stirrer and stir at 700 r / min. Add 0.4 g of azobisisobutyronitrile. Heat to 40 °C and react for 1 h. Then heat to 80 °C and continue to react for 7 h. Filter out the microspheres, wash and dry them.

[0054] Step 2: Add 112g of dichloromethyl ether, 48g of dichloromethane, and 24g of zinc chloride to the second container. After mixing, add 80g of the dried microspheres to this container. Turn on the stirrer and stir at a speed of 400r / min. After heating to 35℃ and reacting for 7h, filter out the microspheres, wash them, and dry them.

[0055] Step 3: Add 100g of diethylenetriamine and 200g of dichloroethane to the third container, mix well, then add 100g of the microspheres prepared in the second container to this container, turn on the stirrer, stir at 400r / min, heat to 25℃ and react for 8h, then add concentrated hydrochloric acid ethanol solution (volume ratio 1:2) and react for 0.5h, then filter out the microspheres, wash and dry them;

[0056] Step 4: Add 120g of the microspheres prepared in the third container to the fourth container, then add 60g of cobalt nitrate and 60g of sodium carbonate in sequence, and finally add 240g of 8% hydrogen peroxide. Turn on the stirrer and stir at a speed of 400r / min. After reacting for 1 hour, filter out the microspheres, wash them with 5% sodium hydroxide aqueous solution, and dry them to obtain the selective descrambled carbonate repellent.

[0057] Example 4

[0058] This embodiment provides a method for preparing a heat-stable salt selective removal agent that repels carbonates, comprising the following steps:

[0059] Step 1: Add 500 ml of water, 0.455 g of polyvinyl alcohol, 0.039 g of methylene blue, 0.306 g of sodium dodecylbenzenesulfonate, 100 g of styrene, and 22 g of 1,3,5-trivinylbenzene to the flask equipped with a stirrer. Turn on the stirrer and stir at 800 r / min. Add 0.6 g of azobisisobutyronitrile (AIBN). Heat to 50 °C and react for 2 h. Then heat to 95 °C and continue reacting for 10 h. Filter out the microspheres, wash them, and dry them.

[0060] Step 2: Add 192g of dichloromethyl ether, 48g of dichloromethane, and 32g of zinc chloride to the second container. After mixing, add 80g of the dried microspheres to this container. Turn on the stirrer and stir at a speed of 600r / min. Heat to 50℃ and react for 8 hours. Then filter out the microspheres, wash them, and dry them.

[0061] Step 3: Add 200g of tetraethylenepentamine and 400g of chloroform to the third container, mix well, add 100g of the microspheres prepared in the second container to this container, turn on the stirrer, stir at 600r / min, heat to 40℃ and react for 10h, then add concentrated hydrochloric acid ethanol solution (volume ratio 1:5) and react for 1h, then filter out the microspheres, wash and dry them.

[0062] Step 4: Add 120g of the microspheres prepared in the third container to the fourth container, then add 120g of cobalt nitrate and 120g of sodium carbonate in sequence, and finally add 360g of 18% hydrogen peroxide. Turn on the stirrer and stir at a speed of 600r / min. After reacting for 3 hours, filter out the microspheres, wash them with 5% sodium hydroxide aqueous solution, and dry them to obtain the selective descrambled carbonate repellent.

[0063] Example 5

[0064] This embodiment provides a method for preparing a heat-stable salt selective removal agent that repels carbonates, comprising the following steps:

[0065] Step 1: Add 400 mL of water, 0.36 g of polyvinyl alcohol, 0.024 g of methylene blue, 0.216 g of sodium dodecylbenzenesulfonate, 85 g of styrene, and 18 g of 1,3,5-trivinylbenzene to a flask equipped with a stirrer. Turn on the stirrer and stir at 700 r / min. Add 0.5 g of azobisisobutyronitrile (AIBN). Heat to 45 °C and react for 1.5 h. Then heat to 88 °C and continue reacting for 8.5 h. Filter out the microspheres, wash them, and dry them.

[0066] Step 2: Add 150g of dichloromethyl ether, 50g of dichloromethane, and 28g of zinc chloride to the second container. After mixing, add 80g of the dried microspheres to this container. Turn on the stirrer and stir at 500r / min. Heat to 42℃ and react for 7.5h. Then filter out the microspheres, wash them, and dry them.

[0067] Step 3: Add 80g of hexamethylenetetramine, 70g of diethylenetriamine, 150g of dichloromethane, and 150g of chloroform to the third container. After mixing, add 100g of the microspheres prepared in the second container to this container. Turn on the stirrer and stir at a speed of 500r / min. Heat to 32℃ and react for 9h. Then add concentrated hydrochloric acid ethanol solution (volume ratio 1:4) and react for 0.8h. Filter out the microspheres, wash them, and dry them.

[0068] Step 4: Add 120g of the microspheres prepared in the third container to the fourth container, then add 90g of cobalt nitrate and 90g of sodium carbonate in sequence, and finally add 300g of 13% hydrogen peroxide. Turn on the stirrer and stir at a speed of 500r / min. After reacting for 2 hours, filter out the microspheres, wash them with 5% sodium hydroxide aqueous solution, and dry them to obtain the selective descrambled carbonate repellent.

[0069] Test case

[0070] This embodiment evaluates the ability of the selective desiccant for repelling carbonates prepared in Examples 1-5 to remove heat-stable salts.

[0071] The specific evaluation method is as follows: the hydrogenated tail gas deep desulfurization formulation of the amine solution of the purification plant was treated by ion exchange, electrodialysis, vacuum distillation and the removal agent of this invention, respectively. The contents of various heat-stable salts and surfactants before and after amine treatment were measured, and the removal rates of various heat-stable salts and the co-removal rates of surfactants were calculated.

[0072] The operation method for treating amine liquid in a purification plant using the removal agent of this invention is as follows: The removal agents prepared in Examples 1-5 are respectively loaded into five glass columns, each with a stopcock at the bottom for discharging liquid. Then, amine liquid from the purification plant is added above the glass columns, the stopcock at the bottom of the glass columns is opened, and the amine liquid is collected in a clean container at the bottom of the glass columns.

[0073] The experimental results are shown in Table 1.

[0074] Table 1 Results of treating amine solutions using conventional methods and the removal agent prepared in this application.

[0075]

[0076] As shown in Table 1, after the hydrogenation tail gas deep desulfurization formulation amine solution was treated with the removal agent provided in Examples 1-5, the co-removal rate of the activator was significantly reduced. Compared with the existing methods, the activator retention rate was increased by more than 93%, and the removal rate of heat-stable salts was ≥95%, with excellent selectivity.

[0077] In summary, the desulfurizing agent provided in this invention has selectivity that existing methods lack: it retains >98% of the active agent in the hydrogenation tail gas deep desulfurization formulation of amine solution, while also achieving the same high thermally stable salt removal rate as existing methods, whereas existing methods retain <6% of the active agent. Therefore, the desulfurizing agent of this invention can solve the problem of reduced desulfurization performance after the reactivation of the hydrogenation tail gas deep desulfurization formulation of amine solution.

Claims

1. A method for preparing a heat-stable salt selective removal agent that repels carbonates, characterized by, It comprises the following steps: Step 1, adding water, dispersant, styrene and crosslinking agent into a first container, starting the stirrer, adding initiator, carrying out reaction, then filtering, washing and drying to obtain first microspheres; Step 2, adding reagent 1 and catalyst into a second container, mixing, then adding the first microspheres into the second container, starting the stirrer, carrying out reaction, then filtering, washing and drying to obtain second microspheres, reagent 1 is a mixture of dichloromethyl ether and dichloromethane, and the catalyst is zinc chloride; Step 3, adding reagent 2 and organic solvent into a third container, mixing, then adding the second microspheres, starting the stirrer, carrying out reaction, then adding concentrated hydrochloric acid ethanol solution and carrying out reaction for 0.5-1 hour, then filtering, washing and drying to obtain third microspheres, reagent 2 comprises one or more of hexamethylenetetramine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine; Step 4, adding the third microspheres into a fourth container, then adding reagent 4 and reagent 5 in sequence, finally adding hydrogen peroxide, starting the stirrer, carrying out reaction, then filtering the fourth microspheres, washing with sodium hydroxide aqueous solution and drying to obtain a heat-stable salt selective removal agent for repelling carbonate, reagent 4 is cobalt nitrate, and reagent 5 is soluble carbonate.

2. The method of claim 1, wherein the method is characterized by, The mass ratio of water, dispersant, styrene, crosslinking agent and initiator in step 1 is 300-500:0.4-0.8:70-100:15-22:0.4-0.

6.

3. The method for preparing a selectively repellent carbonate-stabilized salt remover according to claim 2, characterized in that, The mass ratio of water, dispersant, styrene, crosslinking agent and initiator in step 1 is 400:0.6:85:18:0.

5.

4. The method of claim 2, wherein the method is characterized by, The dispersant is a mixture of polyvinyl alcohol, methine blue and sodium dodecyl benzene sulfonate, and the mass ratio of polyvinyl alcohol, methine blue and sodium dodecyl benzene sulfonate is 50-70:3-6:24-47; the crosslinking agent is trivinylbenzene; and the initiator is azobisdimethyl isobutyronitrile.

5. The method of claim 4, wherein the method is characterized by, The mass ratio of polyvinyl alcohol, methine blue and sodium dodecyl benzene sulfonate is 60:4:

36.

6. The method of claim 2, wherein the method is characterized by, The reaction in step 1 specifically comprises the following steps: after adding the initiator, the temperature is raised to 40-50℃, and the reaction is carried out for 1-2 hours, then the temperature is raised to 80-95℃, and the reaction is carried out for 7-10 hours.

7. The method of claim 1, wherein the method is characterized by: The mass ratio of reagent 1, catalyst and microspheres in step 2 is 2-3:0.3-0.4:1; and the mass ratio of dichloromethyl ether and dichloromethane is 7-8:3-2.

8. The method of claim 1, wherein the method is characterized by: The reaction temperature in step 2 is 35-50℃, and the reaction time is 7-8 hours.

9. The method of claim 1, wherein the method is characterized by, The mass ratio of hydrogen peroxide, reagent 4, reagent 5 and third microspheres is 2-3:0.5-1:0.5-1:1; the concentration of hydrogen peroxide is 8-18%; the reaction temperature is normal temperature after starting the stirrer, and the reaction time is 1-3 hours.

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