A solid amine resin adsorbent, its preparation method and application

Abstract

The application provides a solid amine resin adsorbent and a preparation method and application thereof, and relates to the technical field of low-concentration carbon dioxide capture. The method for preparing the solid amine resin adsorbent by taking macroporous chloromethylation resin as a carrier has simple process and mild reaction conditions, uses ethane-1,2-diamine hydrochloride as a grafting reagent, avoids the crosslinking problem of resin generated in the grafting modification reaction, improves the effective utilization rate of the grafting reagent and the amine group exchange capacity of the solid amine resin adsorbent, and the amine group exchange capacity can be up to 11.2 mmol / g, and the carbon dioxide adsorption capacity can be up to 170 mg / g. Compared with the impregnation method, the amine group reagent of the solid amine resin adsorbent prepared by the grafting modification method is not easy to flow out, the adsorption performance is good after regeneration, and the carbon dioxide adsorption capacity almost remains unchanged after 40 times of cyclic regeneration and use.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide capture technology, and in particular to a solid amine resin adsorbent with high amine exchange capacity, its preparation method, and its application in the decarbonization of gases with low carbon dioxide content. Background Technology

[0002] As a clean energy source with abundant reserves, natural gas has lower carbon dioxide emissions and higher calorific value than traditional fossil fuels, which can meet society's major demand for low-carbon energy. Therefore, natural gas has an increasingly prominent position and role in the global energy system.

[0003] my country's latest national standard for natural gas (GB 17820-2018) stipulates that Class I natural gas requires a carbon dioxide molar fraction of ≤3.0%, and Class II natural gas requires a carbon dioxide molar fraction of ≤4.0%. Therefore, most natural gas must undergo strict carbon dioxide removal before being transported to commercial pipelines. Currently, the main methods suitable for natural gas decarbonization include solvent absorption, pressure swing adsorption, and membrane separation. Among these, amine solvent absorption is the most widely used natural gas decarbonization method in industry. Amine solvent absorption has advantages such as mature technology, large processing capacity, and high selectivity. However, it still has problems such as high regeneration energy consumption, severe equipment corrosion, poor amine solvent volatilization and recycling performance. For natural gas with low carbon dioxide content (below 15%), there is still a problem of incomplete absorption, requiring combined processes for decarbonization. Therefore, developing efficient, long-life, and low-energy-consumption decarbonization technology for low carbon dioxide content natural gas is of great practical significance.

[0004] In recent years, solid amine adsorption technology for carbon dioxide removal has developed rapidly. By modifying porous materials with amine groups to acquire carbon dioxide adsorption properties, this solid amine adsorbent effectively reduces the corrosiveness of organic amines and the volatilization loss during use. The uniform pore distribution, high specific surface area, and pore volume inside the porous material can promote the diffusion of carbon dioxide and improve adsorption efficiency. At the same time, the low heat capacity of solid amines can also reduce the energy consumption of the regeneration process, making it an ideal adsorbent for decarbonizing gases with low carbon dioxide content.

[0005] There are numerous reports on the use of solid amine adsorbents for the adsorption of low-concentration carbon dioxide. For example, CN102343254A discloses a room-temperature solid amine adsorbent for carbon dioxide, which achieves an adsorption capacity of over 2.45 mmol / g for low-concentration carbon dioxide (1.5–2.2 vol%) under room-temperature conditions. CN112337448B discloses a solid amine hollow fiber and its preparation method. Porous hollow fibers are prepared using a steam-immersion induced phase inversion method. Amine groups are grafted onto the porous wall of the hollow fiber through a reaction to obtain solid amine hollow fibers. Carbon dioxide-containing gas is introduced into one end of the hollow fiber tube and flows out through the porous wall from the other end. The carbon dioxide is adsorbed within the hollow fiber by the amine groups. Regeneration can be achieved by heating the solid amine hollow fiber to release the adsorbed carbon dioxide. CN105195113A relates to a solid amine adsorbent for capturing low-concentration carbon dioxide at room temperature, its preparation method, and its application. The adsorbent is a macroporous adsorption resin modified with liquid organic amine and surfactant. The organic amine and surfactant are dissolved in an organic solvent, added to the macroporous adsorption resin, and reacted for a period of time in a rotary evaporator, allowing the organic amine and surfactant to impregnate the pore structure of the resin carrier. Low-concentration carbon dioxide is adsorbed at room temperature, with an adsorption capacity of up to 165.5 mg / g. The solid amine adsorbent preparation methods provided in the above patents are all impregnation methods. Solid amine adsorbents prepared by this method are prone to amine reagent loss, have a short service life, and require additional ammonia removal and purification equipment. Grafting modification, which chemically bonds the grafting reagent to the macroporous adsorption material, can effectively improve the stability of the solid amine adsorbent, extend its service life, and reduce equipment investment and operating costs. However, the grafting reagent is prone to cross-linking during grafting modification, resulting in a low amine exchange capacity of the solid amine resin adsorbent and a reduced carbon dioxide adsorption capacity. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a solid amine resin adsorbent for decarbonization of gases with low carbon dioxide content, its preparation method, and its applications. The method for preparing the solid amine resin adsorbent using macroporous chloromethylated resin as a carrier is simple, with mild reaction conditions. Using ethane-1,2-diamine hydrochloride as a grafting reagent avoids the resin cross-linking problem that occurs during grafting modification, thus improving the effective utilization rate of the grafting reagent and the amine exchange capacity of the solid amine resin adsorbent. The amine exchange capacity can reach up to 11.2 mmol / g, and the carbon dioxide adsorption capacity can reach up to 170 mg / g. Compared with the impregnation method, the solid amine resin adsorbent prepared by the grafting modification method is less prone to amine reagent loss, exhibits good adsorption performance after regeneration, and its carbon dioxide adsorption capacity remains almost unchanged after 40 cycles of regeneration.

[0007] One of the objectives of this invention is to provide a solid amine resin adsorbent.

[0008] The second objective of this invention is to provide a method for preparing the solid amine resin adsorbent.

[0009] A third objective of this invention is to provide an application of the solid amine resin adsorbent.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0011] In a first aspect, the present invention provides a solid amine resin adsorbent, the structure of which is as follows:

[0012]

[0013] Secondly, the present invention provides a method for preparing the above-mentioned solid amine resin adsorbent, comprising the following steps:

[0014]

[0015] (1) Macroporous chloromethylated resin The resin was heated in the presence of a solvent and reacted with ethane-1,2-diamine hydrochloride. After the reaction was completed, the temperature was lowered to room temperature and the solution in the reaction system was filtered. The resin was washed with water until the pH of the water was neutral.

[0016] (2) Soak the resin obtained in step (1) in an aqueous sodium hydroxide solution, then separate the resin and wash it with water until the pH of the water is neutral. After drying, a solid amine resin adsorbent is obtained.

[0017] In some embodiments, the macroporous chloromethylated resin in step (1) has a particle size of 500-800 μm and a specific surface area of ​​20-45 m². 2 / g;

[0018] In some embodiments, the macroporous chloromethylated resin in step (1) has a pore size of 10-25 nm and a pore volume of 0.05-0.3 cm³. 3 / g.

[0019] In some embodiments, in step (1), the solvent is one or more selected from anhydrous tetrahydrofuran, acetonitrile, dichloromethane, 1,4-dioxane, N,N'-dimethylformamide and dimethyl sulfoxide, preferably anhydrous dimethyl sulfoxide.

[0020] In some embodiments, in step (1), the amount of solvent added is 200-400 mL relative to 50 g of chloromethylated resin.

[0021] In some embodiments, in step (1), the mass ratio of macroporous chloromethylated resin to ethane-1,2-diamine hydrochloride is 1:0.5 to 1:1.

[0022] In some embodiments, in step (1), the reaction temperature is 60-80°C and the reaction time is 12-24h.

[0023] In some embodiments, in step (2), the equivalent concentration of the sodium hydroxide aqueous solution is 1-2N.

[0024] In some implementations, the soaking time in step (2) is 12-24 hours.

[0025] Specifically, the preparation method of the solid amine resin adsorbent includes the following steps:

[0026] (1) Add chloromethylated resin, ethane-1,2-diamine hydrochloride and anhydrous dimethyl sulfoxide to a round-bottom flask, then heat to 60-80℃ for 12 hours. After the reaction is completed, cool to room temperature and filter the solution in the reaction system. Wash the resin with deionized water until the pH of the washed aqueous phase is neutral.

[0027] (2) Soak the resin obtained in step (1) in 2N sodium hydroxide solution for 12 hours, then filter out the resin and wash the resin with deionized water until the pH of the washed water phase is neutral; dry it in an oven at 120°C for 6 hours to obtain the solid amine resin adsorbent.

[0028] Thirdly, the present invention provides an application of the above-mentioned solid amine resin adsorbent in the decarbonization of mixed gas with low carbon dioxide content.

[0029] In some embodiments, the application includes the following steps: loading the solid amine resin adsorbent into an adsorption reactor and adjusting the temperature of the adsorption reactor to a set temperature; introducing a carbon dioxide mixture into the adsorption reactor at a set flow rate and pressure, passing it through the adsorbent and then discharging it from the top, and connecting the discharged gas to a flue gas monitor to detect the carbon dioxide content in the gas.

[0030] Preferably, the volume content of carbon dioxide in the carbon dioxide mixture is ≤15%.

[0031] Preferably, the adsorption temperature is 10-40℃, more preferably 20-40℃; the adsorption pressure is 0.1-5.0 MPa, more preferably 0.1-4.0 MPa; and the adsorption space velocity is 1000-3000 h⁻¹. -1 Preferably 2000-3000h -1 .

[0032] Preferably, the application further includes the regeneration of the solid amine resin adsorbent, wherein the regeneration method is temperature-controlled regeneration;

[0033] Preferably, the regeneration temperature is 50-100℃, more preferably 70-100℃, and the flow rate is 200-500mL / min, more preferably 400-500mL / min.

[0034] Technical effects:

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] (1) The synthesis method of solid amine resin adsorbent is simple, the reaction conditions are mild, and the macroporous chloromethylated resin adsorbent material used is easy to prepare.

[0037] (2) Using ethane-1,2-diamine hydrochloride as a grafting agent avoids the resin crosslinking problem generated in the grafting modification reaction, improves the effective utilization rate of the grafting agent and the amine exchange capacity of the solid amine resin adsorbent, the amine exchange capacity can be as high as 11.2 mmol / g, and the carbon dioxide adsorption capacity can be as high as 170 mg / g.

[0038] (3) The solid amine resin adsorbent prepared by chemical grafting modification has good stability, the amine reagent is not easily lost, the adsorption performance is good after regeneration, the service life is long, and the carbon dioxide adsorption capacity remains almost unchanged after 40 cycles of regeneration.

[0039] The present invention has been described in detail above; however, the above embodiments are merely illustrative in nature and are not intended to limit the invention. Furthermore, this document is not limited to the foregoing prior art or the invention itself, or to any theory described in the following embodiments. Attached Figure Description

[0040] Figure 1 The infrared spectroscopy image of the solid amine resin adsorbent prepared in Example 4;

[0041] Figure 2 The carbon dioxide cyclic adsorption capacity is represented by the solid amine resin adsorbent prepared in Example 1. Detailed Implementation

[0042] The present invention will be further described below with reference to the embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0043] Unless otherwise specified, the raw materials, reagents, and methods used in the embodiments are all conventional raw materials, reagents, and methods in the art.

[0044] Amine exchange capacity: Accurately weigh 0.5000g of solid amine resin adsorbent and place it in a 100mL beaker. Use a pipette to measure 50mL of 0.1mol / L hydrochloric acid solution and soak the resin for 24 hours. Use a pipette to measure 10mL of the soaking mother liquor and transfer it to a 100mL beaker. Then dilute it with deionized water to 50mL and titrate it in reverse with an acid-base potentiometric titrator until pH=7.0. Calculate the hydrochloric acid concentration in the mother liquor.

[0045] The formula for calculating amino exchange capacity is as follows:

[0046]

[0047] Example 1

[0048] Take 50g of dried macroporous chloromethylated resin (Hebei Kairui Chemical Co., Ltd., particle size 650μm, specific surface area 30.0m²). 2 / g, pore size 20.0nm, pore volume 0.10cm³ 3 The amine resin was placed in a 500 mL three-necked round-bottom flask, and then 200 mL of anhydrous dimethyl sulfoxide and 25 g of ethane-1,2-diamine hydrochloride (Shanghai Haohong Biomedical Technology Co., Ltd.) were added. After the addition was completed, the reaction system was heated to 60 °C and reacted for 12 hours. After the reaction was completed, the temperature was lowered to room temperature and the solution in the reaction system was filtered. The resin was washed with deionized water until the pH of the washed aqueous phase was neutral. The prepared adsorption resin was soaked in 2N sodium hydroxide solution for 12 hours, and then the resin was filtered out and washed with deionized water until the pH of the washed aqueous phase was neutral. Finally, the adsorption resin was placed in an oven and dried at 120 °C for 6 hours to obtain a solid amine resin adsorbent with an amine exchange capacity of 7.7 mmol / g.

[0049] Example 2

[0050] Take 50g of dried macroporous chloromethylated resin (Hebei Kairui Chemical Co., Ltd., particle size 650μm, specific surface area 30.0m²). 2 / g, pore size 20.0nm, pore volume 0.10cm³ 3 The amine resin was placed in a 500 mL three-necked round-bottom flask, and then 200 mL of anhydrous dimethyl sulfoxide and 50 g of ethane-1,2-diamine hydrochloride (Shanghai Haohong Biomedical Technology Co., Ltd.) were added. After the addition was completed, the reaction system was heated to 60 °C and reacted for 12 hours. After the reaction was completed, the temperature was lowered to room temperature and the solution in the reaction system was filtered. The resin was washed with deionized water until the pH of the washed aqueous phase was neutral. The prepared adsorption resin was soaked in 2N sodium hydroxide solution for 12 hours, and then the resin was filtered out and washed with deionized water until the pH of the washed aqueous phase was neutral. Finally, the adsorption resin was placed in an oven and dried at 120 °C for 6 hours to obtain a solid amine resin adsorbent with an amine exchange capacity of 9.2 mmol / g.

[0051] Example 3

[0052] Take 50g of dried chloromethylated resin (Hebei Kairui Chemical Co., Ltd., particle size 650μm, specific surface area 30.0m²). 2 / g, pore size 20.0nm, pore volume 0.10cm³ 3 The amine resin was placed in a 500 mL three-necked round-bottom flask, and then 200 mL of anhydrous dimethyl sulfoxide and 50 g of ethane-1,2-diamine hydrochloride (Shanghai Haohong Biomedical Technology Co., Ltd.) were added. After the addition was completed, the reaction system was heated to 80 °C and reacted for 12 hours. After the reaction was completed, the temperature was lowered to room temperature and the solution in the reaction system was filtered. The resin was washed with deionized water until the pH of the washed aqueous phase was neutral. The prepared adsorption resin was soaked in 2N sodium hydroxide solution for 12 hours, and then the resin was filtered out and washed with deionized water until the pH of the washed aqueous phase was neutral. Finally, the adsorption resin was placed in an oven and dried at 120 °C for 6 hours to obtain a solid amine resin adsorbent with an amine exchange capacity of 10.0 mmol / g.

[0053] Example 4

[0054] Take 50g of dried chloromethylated resin (Hebei Kairui Chemical Co., Ltd., particle size 700μm, specific surface area 40.0m²). 2 / g, pore size 23.0nm, pore volume 0.20cm³ 3 The amine resin (e.g., 1,2-diamine hydrochloride) was placed in a 500 mL three-necked round-bottom flask, followed by the addition of 200 mL anhydrous dimethyl sulfoxide and 50 g ethane-1,2-diamine hydrochloride (Shanghai Haohong Biomedical Technology Co., Ltd.). After the addition, the reaction system was heated to 80 °C and reacted for 12 hours. After the reaction, the temperature was lowered to room temperature, and the solution in the reaction system was filtered. The resin was washed with deionized water until the pH of the washed aqueous phase was neutral. The prepared adsorption resin was soaked in 2N sodium hydroxide solution for 12 hours, then the resin was filtered out and washed with deionized water until the pH of the washed aqueous phase was neutral. Finally, the adsorption resin was dried in an oven at 120 °C for 6 hours to obtain a solid amine resin adsorbent (infrared analysis diagram as shown). Figure 1 As shown in the figure, the amino exchange capacity is 11.2 mmol / g.

[0055] Comparative Example 1

[0056] The difference between this comparative example and Example 4 is that ethane-1,2-diamine hydrochloride was replaced with ethylenediamine, which has an amino exchange capacity of 4.6 mmol / g.

[0057] Comparative Example 2

[0058] The difference between this comparative example and Example 4 is that ethane-1,2-diamine hydrochloride is replaced with tetramethylethylenediamine, which has an amino exchange capacity of 3.5 mmol / g.

[0059] Comparative Example 3

[0060] The difference between this comparative example and Example 4 is that ethane-1,2-diamine hydrochloride was replaced with ethylenediamine (bis) hydrochloride, which prevented the reaction from occurring.

[0061] Application Example 1

[0062] Carbon dioxide adsorption was performed by loading 30g of the solid amine adsorption resin prepared in Example 4 into an adsorption reactor. The adsorption conditions were: carbon dioxide content in the mixed gas was 5%, adsorption temperature was 25℃, adsorption pressure was 3.0MPa, and adsorption space velocity was 2500h⁻¹. -1 When the carbon dioxide concentration at the outlet is greater than 3%, adsorption is stopped. The carbon dioxide adsorption capacity is calculated and the resin is regenerated under variable temperature conditions. The regeneration conditions are: regeneration temperature 70℃, nitrogen purging flow rate 400ml / min. Regeneration ends when the carbon dioxide concentration at the outlet drops to 0.0%. After the adsorption reactor is cooled to 25℃, the adsorption-desorption operation can be carried out again.

[0063] from Figure 2 As can be seen from the carbon dioxide cyclic adsorption graph, the adsorption capacity of the adsorbent sample remained basically unchanged after 40 cycles, indicating that the adsorbent has good adsorption / regeneration stability and good potential for industrial application.

[0064] Application Example 2

[0065] Carbon dioxide adsorption was performed by loading 30g of the solid amine adsorption resin prepared in Example 4 into an adsorption reactor. The adsorption conditions were as follows: carbon dioxide content in the mixed gas was 10%, adsorption temperature was 25℃, adsorption pressure was 3.0MPa, and adsorption space velocity was 2500h⁻¹. -1 The adsorption stopped when the carbon dioxide concentration at the outlet exceeded 3%, and the carbon dioxide adsorption capacity was 162 mg / g.

[0066] Application Example 3

[0067] Carbon dioxide adsorption was performed by loading 30g of the solid amine adsorption resin prepared in Example 4 into an adsorption reactor. The adsorption conditions were as follows: carbon dioxide content in the mixed gas was 15%, adsorption temperature was 25℃, adsorption pressure was 3.0MPa, and adsorption space velocity was 2500h⁻¹. -1 The adsorption stopped when the carbon dioxide concentration at the outlet exceeded 3%, and the carbon dioxide adsorption capacity was 158 mg / g.

[0068] Application Example 4

[0069] 30g of solid amine adsorption resin prepared in Comparative Example 2 was loaded into an adsorption reactor for carbon dioxide adsorption. The adsorption conditions were: carbon dioxide content in the mixed gas was 15%, adsorption temperature was 25℃, adsorption pressure was 3.0MPa, and adsorption space velocity was 2500h⁻¹. -1 The adsorption stopped when the carbon dioxide concentration at the outlet exceeded 3%, and the carbon dioxide adsorption capacity was 43 mg / g.

[0070] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and substance defined by the claims of the present invention; and such modifications or substitutions are still within the scope defined by the claims of the present invention.

Claims

1. A method for preparing a solid amine resin adsorbent, characterized in that, Includes the following steps: (1) Chloromethylated resin The resin was heated in the presence of a solvent and reacted with ethane-1,2-diamine hydrochloride. After the reaction was completed, the temperature was lowered to room temperature and the solution in the reaction system was filtered. The resin was washed with water until the pH of the water was neutral. (2) Soak the resin obtained in step (1) in an aqueous sodium hydroxide solution, then separate the resin and wash it with water until the pH of the water is neutral. After drying, a solid amine resin adsorbent is obtained.

2. The preparation method according to claim 1, characterized in that, The chloromethylated resin in step (1) has a particle size of 500-800 μm and a specific surface area of ​​20-45 m². 2 / g; pore size 10-25nm, pore volume 0.05-0.3cm³ 3 / g.

3. The preparation method according to claim 1, characterized in that, In step (1), the solvent is one or more selected from anhydrous tetrahydrofuran, acetonitrile, dichloromethane, 1,4-dioxane, N,N'-dimethylformamide and dimethyl sulfoxide; The amount of solvent added is 200-400 mL relative to 50 g of chloromethylated resin.

4. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of chloromethylated resin to ethane-1,2-diamine hydrochloride is 1:0.5 to 1:

1.

5. The preparation method according to claim 1, characterized in that, In step (1), the reaction temperature is 60-80℃ and the reaction time is 12-24h.

6. The preparation method according to claim 1, characterized in that, In step (2), the equivalent concentration of the sodium hydroxide aqueous solution is 1-2N; In step (2), the soaking time is 12-24 hours.

7. The application of a solid amine resin adsorbent prepared by the preparation method according to any one of claims 1-6 in the decarbonization of carbon dioxide mixed gas.

8. The application according to claim 7, characterized in that, The application includes the following steps: loading the solid amine resin adsorbent into an adsorption reactor and adjusting the temperature to 10-40℃; and introducing a carbon dioxide mixture at an adsorption space velocity of 1000-3000 h⁻¹. -1 The gas is introduced from the bottom of the reactor at an adsorption pressure of 0.1-5.0 MPa, passes through the adsorbent, and is discharged from the top. The discharged gas is connected to a flue gas monitor to detect the carbon dioxide content in the gas. The volumetric content of carbon dioxide in the carbon dioxide mixture is ≤15%.

9. The application according to claim 8, characterized in that, The application also includes the regeneration of solid amine resin adsorbents, wherein the regeneration method is temperature-controlled regeneration; The regeneration temperature is 50-100℃, and the flow rate is 200-500mL / min.

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