Application of hierarchical pore H beta molecular sieve catalyst in catalyzing organic amine solution to desorb CO2

Abstract

The invention discloses an application of a hierarchical pore H beta molecular sieve catalyst in catalyzing an organic amine solution to desorb CO2, a preparation method of the hierarchical pore H beta molecular sieve catalyst comprises the following steps: dissolving H beta molecular sieve powder in an acidic or alkaline solution with a certain concentration to obtain a mixed solution A; stirring the mixed solution A at a certain temperature for a period of time to obtain a mixture B; carrying out solid-liquid suction filtration separation on the mixed solution B, washing with deionized water to be neutral, and drying to obtain a mixture C; and stirring the mixed solution C in an ammonium salt solution at a certain temperature for a period of time, washing with deionized water, drying and calcining to obtain the hierarchical pore H beta molecular sieve. Compared with the prior art, the preparation process of the catalyst is simple and convenient, and raw materials are cheap and easy to obtain; the catalytic desorption performance is superior to that of an H beta catalyst and other single molecular sieve catalysts; the catalyst is easy to separate, has good stability and can be recycled; the CO2 absorption performance of the organic amine solution is not influenced.

Description

Technical Field

[0001] The present invention belongs to the technical field of CO2 capture in coal-fired power plants, and in particular relates to the application of a multi-level pore Hβ molecular sieve catalyst in catalyzing the desorption of CO2 by an organic amine solution. Background Art

[0002] Fossil fuels remain the dominant energy source in the global energy system. However, with the large-scale consumption of fossil fuels, carbon dioxide emissions have skyrocketed, triggering a series of environmental problems, including an intensified greenhouse effect and frequent extreme weather events. Power generation, as the primary CO2 emitter, accounts for over 60% of total CO2 emissions, making it a key breakthrough in controlling carbon emissions. In the field of CO2 capture in coal-fired power plants, post-combustion capture, pre-combustion capture, and oxyfuel combustion constitute the main technical approaches. Post-combustion CO2 capture, due to its excellent compatibility with existing coal-fired power plant equipment, currently holds the greatest potential for emission reduction. Among various CO2 capture methods, chemical absorption using organic amine solutions stands out for its rapid absorption rate, large absorption capacity, and solvent recyclability. It is currently the most mature and widely used CO2 capture technology. However, its large-scale deployment faces significant obstacles. Traditional thermal desorption methods require high temperatures during the regeneration of the CO2-rich amine solution, resulting in high energy consumption and a direct increase in equipment investment and operating costs by 60-70%. Therefore, developing efficient and energy-saving desorption technology and significantly reducing the heat energy consumption in the carbon dioxide capture process are the key to promoting the large-scale application of organic amine solution carbon dioxide absorption method in coal-fired power plants.

[0003] Existing research efforts are largely focused on developing new amine solvents, phase-change solvents, and mixed amine solvents, as well as optimizing CO2 absorption-desorption processes, to reduce the low CO2 desorption rate and high regeneration energy consumption during CO2 capture. However, since traditional CO2 desorption temperatures range from 120 to 140°C, the significant energy consumption is due to the large-scale vaporization of water within this temperature range. Therefore, desorbing CO2 using organic amine solutions at lower temperatures (<100°C) while ensuring a faster CO2 desorption rate can significantly reduce solvent regeneration energy consumption and improve the economic practicality of organic amine CO2 capture technology. To address the high regeneration energy consumption of CO2-rich amine solutions, Sun et al. applied hierarchical HZSM-5 to the CO2 regeneration reaction of 5M MEA solutions, reducing energy consumption by up to 28.5%. (Sun Q, Gao H, Sema T, et al. Chemical Engineering Journal, 2023, 469:143871.) To further reduce energy consumption, Fu et al. loaded Ni onto Hβ molecular sieve, reducing regeneration energy consumption by 30.16%. (Fu L, Gong J, Li H, et al. Separation and Purification Technology, 2025, 361: 131046.) To further reduce the energy consumption of CO2-rich amine solution regeneration, thereby lowering CO2 capture costs and improving the practicality of amine-based CO2 capture, the development and design of new, highly efficient solid acid catalysts for use in the regeneration of CO2-rich amine solutions is of great practical significance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to synthesize a solid acid catalyst with excellent performance and use it to catalytically reduce the regeneration energy consumption of CO2-rich organic amine solution, thereby reducing the cost of CO2 capture by the organic amine method.

[0005] The technical solution of the present invention is to provide an application of a multi-level pore Hβ molecular sieve catalyst in catalytic CO2 desorption;

[0006] (1) Hβ molecular sieve powder is mixed with an acid-base solution to form a dispersion system to obtain a mixture A;

[0007] (2) Stirring the mixed solution A for a period of time to obtain a mixture B;

[0008] (3) Separate the solid and liquid of the mixed solution B by filtration, wash with deionized water until neutral, and dry to obtain a mixture C;

[0009] (4) The mixed solution C is stirred, washed with deionized water until neutral, dried and calcined to obtain a multi-level pore Hβ molecular sieve.

[0010] Preferably, in step (1), the solid-liquid ratio of the Hβ molecular sieve to the acid-base solution is 1:15-2:1.

[0011] Preferably, the acid or base is one or more of sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), sodium hydroxide (NaOH), ammonium chloride (NH4Cl), citric acid (CA), and hydrochloric acid (HCl).

[0012] Preferably, in step (2), the stirring treatment time is more than 20 minutes, preferably 1-2.5 hours.

[0013] Preferably, in step (2), the stirring temperature is above 40°C, more preferably 50°C.

[0014] Preferably, in step (3), the drying time is 10-15 h.

[0015] Preferably, in step (4), the stirring time is more than 30 min, more preferably 0.8-1.2 h.

[0016] Preferably, in step (4), the stirring temperature is above 50°C, more preferably 70-100°C.

[0017] Preferably, in step (4), the ammonium salt is one or more of ammonium chloride (NH4Cl), ammonium nitrate (NH4NO3), ammonium sulfate ((NH4)2SO4), and ammonium bicarbonate (NH4HCO3).

[0018] Preferably, in step (4), the calcination temperature is 300-800°C, and the calcination time is 2-12 h.

[0019] The present invention synthesizes the above-mentioned catalyst by an acid-base impregnation method. The main process is: dissolving an appropriate amount of Hβ molecular sieve powder in an acid-base solution of a certain concentration to obtain a mixed solution A; stirring the mixed solution A to obtain a mixture B; filtering the mixed solution B to separate the solid and liquid, washing it with deionized water until it is neutral, and drying it to obtain a mixture C; stirring the mixed solution C, washing it with deionized water until it is neutral, and drying and calcining it at a specific temperature to obtain the target product catalyst X-Hβ.

[0020] The catalyst of the present invention can be represented as follows: X-Hβ, where X represents an acid or base. This catalyst, X-Hβ, is used in the regeneration of rich amine solvents in conventional organic amine solvent CO2 capture processes, significantly reducing regeneration energy consumption. This is primarily due to the inherent acidity of Hβ, which imparts a certain catalytic effect. Combined with its multi-level pore structure (mesopore-micropore synergistic effect), this unique pore-acidity synergistic effect effectively improves reaction and mass transfer efficiency.

[0021] Organic amine solvents used for CO₂ absorption include traditional amine solutions such as monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), N-methyldiethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP), and piperazine (PZ), as well as newer amine solutions such as 4-(diethylamino)-2-butanol (DEAB), diethyleneamine hydrochloride (DETA), diethylaminoethyl (DEAE), and various mixed amine solvents such as MEA-DEA and MEA-MDEA. The concentration of the amine aqueous solvent ranges from 1 to 7 mol / L.

[0022] The catalytic regeneration temperature of rich amine solvent is 80-100 ℃. The filling / loading methods of the catalyst in the traditional packed tower include but are not limited to wrapping with fillers, covering the filler surface by impregnation, replacing part of the fillers and random filling of the catalyst.

[0023] The beneficial effects of the present invention are:

[0024] (1) The catalyst preparation process is simple and the raw materials are cheap and easily available.

[0025] (2) The catalyst has excellent desorption performance and its catalytic performance is stronger than traditional catalysts such as single molecular sieve, clay, metal oxide, etc.

[0026] (3) The catalyst is easy to separate, has good stability and good recyclability.

[0027] (4) It has no effect on the CO2 absorption performance of organic amine solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The X-ray diffraction spectrum of the catalyst in Example 1 is shown.

[0029] Figure 2 The figure shows the Fourier infrared spectrum of the catalyst in Example 1.

[0030] Figure 3 Attached diagram showing the N2 adsorption and desorption of the catalyst in Example 1.

[0031] Figure 4 It represents a laboratory-scale batch desorption device for CO2-rich amine solution.

[0032] Table 1 Comparison of catalyst desorption energy consumption of Examples and Control Examples. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the embodiments.

[0034] Example 1: Na2CO3-NH4Cl-Hβ catalyst

[0035] In the first step, 10 g of molecular sieve was dissolved in 100 ml of sodium carbonate solution to obtain a mixture A; the mixture A was stirred at 50 ° C for 2 h to fully mix and disperse the two substances to obtain a mixture B; the mixture B was separated by solid-liquid filtration, washed with deionized water until neutral, and dried at 100 ° C for 12 h to obtain a mixture C; the mixture C was added to 100 ml of 1.0 mol / L ammonium chloride solution, stirred at 80 ° C for 1 h, washed with deionized water until neutral, dried at 100 ° C for 12 h, and calcined at 550 ° C for 6 h to obtain a catalyst, a hierarchical pore Hβ molecular sieve Na2CO3-NH4Cl-Hβ.

[0036] Comparative Example 1: Hβ Catalyst

[0037] As a comparison, the Hβ catalyst was the same Hβ used in the Na2CO3-NH4Cl-Hβ synthesis process.

[0038] Figure 3 This is the N2 adsorption and desorption experiment of the catalyst in Example 1. Figure 3 It can be seen that compared with the single Hβ catalyst, an obvious type IV curve (P / P0>0.4) appears on the catalyst Na2CO3-NH4Cl-Hβ, indicating that the multi-level pores are well formed.

[0039] Example 2:

[0040] The same as Example 1, except that during the catalyst preparation process, sodium carbonate was replaced with citric acid. The obtained catalyst was marked as CA-Hβ.

[0041] Example 3

[0042] The same as Example 1, except that the ammonium chloride exchange in step (4) was not performed during the catalyst preparation process, and the obtained catalyst was marked as Na2CO3-Hβ.

[0043] Example 4

[0044] The same as Example 1, except that the sodium carbonate reaction in step (2) was not performed during the catalyst preparation process, and the obtained catalyst was marked as NH4Cl-Hβ.

[0045] Regeneration process of catalytic desorption of CO2-rich monoethanolamine solvent

[0046] Laboratory scale batch desorption unit for CO2-rich amine solution Figure 2As shown, the main body is a 500 ml three-necked flask with a thermometer inserted in the middle. A condenser reflux device is installed on the right side of the flask to prevent volatilization of the amine solution, and an air inlet is installed on the left side. The three-necked flask is equipped with a magnetic stirrer, and below the flask is an oil bath with magnetic stirring function. The desorption energy consumption (kJ / mol) is defined as the energy required to desorb 1 mol of CO2. It is calculated using an electric meter, and the heat is provided by the oil bath. The amine solution used for desorption is a monoethanolamine solution (MEA) with a concentration of 5 mol / L and a rich amine loading of 0.525 CO2 / mol amine. The catalyst used is prepared according to the above-mentioned implementation method. The specific operation process is as follows: 200 ml of the CO2-rich monoethanolamine solution (MEA) to be desorbed is added to the flask, and 2.5 g of the above-mentioned catalyst is added at a ratio of 1.25%. The three-necked flask is placed in an oil bath and heated to the desired desorption temperature of 90°C. The experimental results are shown in Table 1: Table 1 Comparison of catalyst desorption energy consumption of Examples and Control Examples catalyst Energy consumption ratio (%) Energy consumption reduction (%) blank 100 0 Comparative Example 1: Hβ 76.8 23.2 <![CDATA[Na2CO3-NH4Cl-Hβ]]> 55.9 44.1 CA-Hβ 62.9 37.1 <![CDATA[Na2CO3-Hβ]]> 65.4 34.6 <![CDATA[NH4Cl-Hβ]]> 65.2 34.8 As can be seen from the above table, compared with blank MEA, the addition of catalysts significantly reduced the desorption energy consumption of MEA, and the performance of the catalysts prepared in the examples was better than that of a single catalyst.

Claims

1. Application of multi-level pore Hβ molecular sieve catalyst in catalyzing CO2 desorption from organic amine solution, characterized in that: The catalyst is a traditional microporous Hβ molecular sieve converted into a multi-level pore structure; The specific preparation method of the catalyst is as follows: (1) mixing Hβ molecular sieve powder with an acid or alkaline solution to form a dispersion system to obtain a mixture A; (2) stirring the mixed solution A for a period of time to obtain a mixture B; (3) separating the solid and liquid from the mixed solution B by suction filtration, washing with deionized water, and drying to obtain a mixture C; (4) The mixed solution C and the ammonium salt solution are stirred, washed with deionized water until neutral, dried and calcined to obtain a multi-level pore Hβ molecular sieve.

2. The use according to claim 1, characterized in that In step (1), the solid-liquid ratio of the Hβ molecular sieve powder to the solution is 1:15-2:

1.

3. The use according to claim 1, characterized in that In step (2), the stirring treatment time is 1-2.5 hours and the temperature is 30-80°C.

4. The use according to claim 1, characterized in that In step (2), the stirring temperature is 30-80°C.

5. The use according to claim 1, characterized in that In step (3), the drying time is 8-12 h.

6. The use according to claim 1, characterized in that In step (4), the stirring time is 0.5-3 h.

7. The use according to claim 1, characterized in that In step (4), the stirring temperature is 60-120°C.

8. The use according to claim 1, characterized in that In step (4), the drying temperature is 80-120°C and the drying time is 8-12 h.

9. The use according to claim 1, characterized in that In step (4), the calcination temperature is 300-700 °C, and the calcination time is 2-8 h.

10. The use according to claim 1, characterized in that The mesopore-micropore synergistic effect of the multi-level pore Hβ molecular sieve effectively improves the accessibility of active sites.

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