Preparation method and application of co-based spinel material for catalytic low-temperature regeneration of rich-amine solution
By preparing Co-based spinel catalysts rich in acid active sites and employing a core-shell structure and acid etching strategy, the problem of high desorption energy consumption of CO2 absorbents in the organic amine method was solved, achieving low-temperature and high-efficiency catalytic regeneration, extending catalyst life and reducing energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-11
- Publication Date
- 2026-08-04
AI Technical Summary
Existing organic amine-based CO2 absorbents have high desorption energy consumption, which reduces the recyclability of the absorbent and increases the economic cost of the process.
A catalyst rich in acid-active sites was prepared by co-precipitation using Co-based spinel material. The stability and activity of the catalyst were enhanced by core-shell structure and acid etching strategy. A core-shell structured Co-based composite metal oxide catalyst was prepared by using tetrabutyl titanate to form a TiO2 core-shell structure and combining it with sulfuric acid solution impregnation to anchor the acidification groups.
The low-temperature conditions significantly improved the regeneration rate of the amine-rich solution, extended the catalyst's operating life, reduced energy consumption, and enhanced the catalyst's reusability.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of catalytic regeneration of CO2 absorbents, specifically to a method for preparing Co-based spinel materials for low-temperature regeneration of amine-rich solutions and their application in carbon capture processes based on chemical absorption. Background Technology
[0002] In recent years, global warming caused by CO2 emissions has received widespread attention. Reducing CO2 emissions from fossil fuel combustion is a key measure to address climate change. Chemical absorption is currently the most widely used commercial post-combustion capture technology, with organic amine methods offering advantages such as fast reaction rates and high selectivity. However, currently reported organic amine absorbents generally suffer from high desorption energy consumption (3.6-4.0 GJ / tCO2 in traditional alkanolamine processes), reducing the recyclability of the absorbent and increasing the economic cost of the process. Solid acid catalysts, due to their abundant BASs and LASs, can significantly enhance the CO2 desorption rate and lower the desorption temperature, making them a promising technology for enhancing absorbent regeneration.
[0003] Co-based spinels are a class of materials that have attracted widespread attention in the field of catalysis, possessing the advantages of low cost and high activity. Furthermore, their active sites and the number of electrons can be regulated through specific doping and hybridization, providing various possibilities for improving catalyst performance. In addition, compared to single metal oxides, the difference in electron affinity of elements in composite metal oxides significantly alters the electronic coordination state around metal ions, thus affecting the number of acid-active sites. Therefore, Co-based spinels can achieve highly efficient catalysis for CO2 desorption from amine-rich solutions by changing the proportion of transition metal doping. Meanwhile, for CO2 desorption from amine-rich solutions, electron transfer in solution is a crucial step in the catalytic process. The synthesis of core-shell structures can not only effectively delay the hydrolysis and etching of the core material under high-temperature alkaline conditions but also induce lattice distortion at the core-shell interface, thereby regulating and altering the electron density of some atoms in the core material, enhancing electron transport capacity, and accelerating the catalytic reaction rate. Moreover, acid etching strategies can not only compensate for the lack of acid-active sites in the catalyst by anchoring and grafting acid-active groups but also improve catalyst reusability through repeated soaking and loading, thus extending the catalyst's lifespan under high-temperature alkaline conditions. Therefore, designing and synthesizing Co-based composite metal oxide-enhanced amine solution regeneration catalysts with multiple acid active sites and long operating lifetimes is of great significance for the development of carbon capture processes based on chemical absorption. Summary of the Invention
[0004] This invention provides a method for preparing a Co-based spinel material for the low-temperature regeneration of rich amine solutions and its application. The prepared catalyst possesses abundant acid-active sites and high stability, exhibiting excellent low-temperature catalytic performance in the catalytic regeneration of rich amine solutions (it can increase the catalytic regeneration rate by 103% at 98℃). Furthermore, the raw materials used in this catalyst are inexpensive and readily available, the preparation method is energy-efficient, and the yield is high, demonstrating potential application prospects in the field of catalytic regeneration of rich amine solutions.
[0005] The purpose of this invention is to provide a method for preparing a high-performance Co-based composite metal oxide enhanced amine solution regeneration catalyst, as well as the catalyst prepared by this method and its application in enhanced amine solution regeneration.
[0006] The technical solution of the present invention is as follows:
[0007] A method for preparing a high-performance Co-based composite metal oxide-enhanced amine-rich solution regeneration catalyst includes the following steps:
[0008] 1) Measure out deionized water and anhydrous ethanol in a volume ratio of 1:1, mix them thoroughly to form solution A; weigh out (CH3COO)2Co·4H2O and acetate, add them to solution A, and stir until completely dissolved; weigh out anhydrous oxalic acid, dissolve it in deionized water, mix thoroughly, and record this as solution B; wait until solution A is completely clear, then introduce solution B into it;
[0009] 2) Stir and age the mixed solution for 12-15 hours, then centrifuge and wash it. After drying, transfer it to a muffle furnace and calcine it in air at 450-550°C for 2-4 hours to obtain a Co-based composite oxide catalyst.
[0010] 3) Measure anhydrous ethanol and ammonia solution, and mix them to obtain solution C. Weigh out the Co-based composite oxide and disperse it evenly in solution C. Transfer solution C to a water bath at 35-55℃, and add tetrabutyl titanate dropwise to the solution. Stir continuously for 20-24 hours. Centrifuge and wash the precipitate, dry it, and transfer it to a muffle furnace. Calcinate it in air at 450-550℃ for 2-4 hours to obtain a core-shell structured Co-based composite oxide catalyst.
[0011] 4) Prepare a sulfuric acid solution, weigh out the core-shell structured Co-based composite oxide catalyst, impregnate for 1-12 hours, filter, wash with water, and dry to obtain the sulfuric acid-acidified core-shell structured Co-based composite oxide catalyst.
[0012] This invention uses anhydrous oxalic acid solution as a co-precipitant to form a precipitate of (CH3COO)2Co·4H2O and acetate dissolved in H2O and C2H5OH. The precipitate is then aged for 12 hours under stirring to form a transition metal-doped Co-based composite metal oxide. An ammonia solution is used to provide an alkaline environment to promote the hydrolysis of tetrabutyl titanate, resulting in the kinetic coating of a TiO2 core-shell structure. Sulfuric acid solution is used for impregnation to anchor and graft acidified groups, forming a sulfuric acid-acidified core-shell structure Co-based spinel. The catalyst prepared by this invention exhibits excellent low-temperature enhanced catalytic activity for the regeneration of amine-rich solutions.
[0013] In this invention, firstly, a Co-based spinel catalyst with abundant acidic active sites was prepared by co-precipitation using (CH3COO)2Co·4H2O and acetate as raw materials and anhydrous oxalic acid as a co-precipitant; secondly, a core-shell structured Co-based composite metal oxide catalyst was prepared by utilizing the alkalinity of ammonia solution to promote the hydrolysis of tetrabutyl titanate in anhydrous ethanol; thirdly, a highly active sulfuric acid-acidified core-shell structured Co-based composite metal oxide catalyst was prepared by impregnation with sulfuric acid solution to anchor and graft acidified groups; and fourthly, various Co-based composite metal oxide catalysts can be prepared using this method.
[0014] In step 1), the molar ratio of (CH3COO)2Co·4H2O to acetate is x:3-x, and more preferably 1:2;
[0015] The acetate is at least one of (CH3COO)2Mn, (CH3COO)2Cu, and (CH3COO)2Fe.
[0016] The stirring and dissolution conditions are: continuous stirring at room temperature for 20–40 minutes, more preferably 30 minutes. With the addition of a sealing film, stirring at room temperature for 30 minutes ensures complete dissolution of (CH3COO)2Co·4H2O and acetate.
[0017] In step 2), the aging conditions for the mixed solution are continuous stirring for 12 to 15 hours, with the most preferred method being stirring for 12 hours.
[0018] The precipitate is centrifuged and washed with water 3 to 5 times, and with ethanol 1 to 3 times. The preferred number of centrifugation and washing is 3 times with water and 1 time with ethanol.
[0019] Drying conditions: Dry at 70-90°C for 10-14 hours, with the most preferred method being drying at 80°C for 12 hours.
[0020] Calcination conditions: Calcination at 450-550°C for 2-4 hours in air atmosphere, with the most preferred method being calcination at 500°C for 2 hours.
[0021] In step 3), solution C is transferred to a water bath at 35-55°C, and preferably to a water bath at 45°C.
[0022] The solution is stirred continuously for 20 to 24 hours, with 24 hours being the optimal stirring time.
[0023] The precipitate is washed 5 to 7 times by centrifugation with anhydrous ethanol, with the optimal method being to wash the precipitate 5 times with anhydrous ethanol until the solution is neutral.
[0024] Drying conditions: Dry at 70-90°C for 10-14 hours, with the most preferred method being drying at 80°C for 12 hours.
[0025] Calcination conditions: Calcination at 450-550°C for 2-4 hours in air atmosphere, with the most preferred method being calcination at 500°C for 2 hours.
[0026] In step 4), the molar concentration of the sulfuric acid solution is 0.5 mol / L to 1.5 mol / L, with the most preferred molar concentration being 1.0 mol / L.
[0027] The catalyst is impregnated in sulfuric acid solution for 1 to 12 hours, with the most preferred impregnation time being 10 hours.
[0028] Drying conditions: Dry at 70-90°C for 10-14 hours, with the most preferred method being drying at 80°C for 12 hours.
[0029] In step 1), the acetate is (CH3COO)2Mn, and the chemistry of the high-performance Co-based composite metal oxide-enhanced amine-rich solution regeneration catalyst is SO4 / TiO2@Mn. x Co 3-x O4, x and 3-x represent the molar ratios of (CH3COO)2Mn and (CH3COO)2Co in different samples, respectively.
[0030] The preferred molar ratio of (CH3COO)2Mn to (CH3COO)2Co is 2 / 1.
[0031] A high-performance Co-based composite metal oxide enhanced amine solution regeneration catalyst prepared by the above preparation method.
[0032] The above-mentioned high-performance Co-based composite metal oxide enhanced amine solution regeneration catalyst is applied in carbon capture processes based on chemical absorption (catalytic regeneration of CO2 absorbent).
[0033] Compared with the prior art, the present invention has the following advantages:
[0034] 1. A shell coating strategy is adopted to delay the hydrolysis and deactivation of the catalyst, prevent the loss of active acid sites, and extend the service life of the catalyst.
[0035] 2. The specific surface area of the catalyst is increased by acid etching strategy, and acid active groups are anchored and grafted. The acid radical groups uniformly loaded on the catalyst surface can further increase the total number of active sites of the catalyst, and the catalyst can be regenerated by repeated impregnation.
[0036] 3. Based on the preparation method, high-performance Co-based composite oxide catalysts with different transition metal doping can be prepared by changing the type of acetate. Attached Figure Description
[0037] Figure 1 The XRD results are for the Co-based composite oxide catalyst.
[0038] Figure 2 The SEM results are for the Co-based composite oxide catalyst.
[0039] Figure 3 TEM results for Co-based composite oxide catalysts.
[0040] Figure 4 The Py-IR results are for Co-based composite oxide catalysts.
[0041] Figure 5 The catalytic rates for the regeneration of MEA solutions in Examples 1 and 4-8 are given. Detailed Implementation
[0042] Example 1
[0043] Weigh 4.9018 g (0.02 mol) of (CH3COO)2Mn·4H2O and 2.4908 g of (CH3COO)2Co·4H2O and dissolve them in a mixed solution prepared with 50 mL of deionized water and 50 mL of anhydrous ethanol. Stir for 30 min until completely dissolved to form solution A. Weigh 2.1607 g of anhydrous oxalic acid and dissolve it in 50 mL of anhydrous ethanol, and denote this as solution B. Slowly pour solution B into solution A and continue stirring for 12 hours to age the mixture, resulting in a pink precipitate. Centrifuge the precipitate, wash it three times with water and once with anhydrous ethanol, dry it at 80 °C for 12 hours, and then transfer it to a muffle furnace and calcine it at 500 °C for 2 hours in air atmosphere to obtain the transition metal-doped Co-based composite oxide Mn2CoO4. Subsequently, 150 mL of anhydrous ethanol was measured and 0.9 mL of 25 wt% ammonia solution was added. 0.5 g of Mn2CoO4 was weighed and uniformly dispersed in the above solution. After uniform dispersion, the solution was transferred to a water bath at 45 °C. 10 mL of tetrabutyl titanate was slowly added dropwise to the solution, and the mixture was stirred continuously for 24 hours. The solution was washed five times by centrifugation with anhydrous ethanol until it became neutral. The precipitate was dried at 80 °C for 12 hours and then calcined at 500 °C for 2 hours in air to obtain the core-shell structured Co-based composite oxide TiO2@Mn2CoO4. Finally, 15 mL of 1 mol / L sulfuric acid solution was prepared, and 1.5 g of TiO2@Mn2CoO4 was weighed and dispersed in the sulfuric acid solution. The mixture was stirred for 10 hours, then filtered, washed with water, and dried at 80 °C for 12 hours to obtain the sulfuric acid-acidified core-shell structured Co-based composite oxide SO4 / TiO2@Mn2CoO4.
[0044] XRD results of sulfuric acid-acidified core-shell structured Co-based composite oxide catalysts are as follows: Figure 1 As shown in the figure, the prepared catalyst exhibits characteristic peaks of (Co,Mn)(Co,Mn)₂O₄ and anatase TiO₂.
[0045] SEM results of sulfuric acid-acidified core-shell structured Co-based composite oxide catalysts are as follows: Figure 2 As shown in the figure, the catalyst has a rough porous structure.
[0046] TEM results of sulfuric acid-acidified core-shell structured Co-based composite oxide catalysts are as follows: Figure 3 As shown in the figure, the prepared catalyst exhibits clear lattice fringes and numerous lattice defects.
[0047] Py-IR results for sulfuric acid-acidified core-shell structured Co-based composite oxide catalysts are as follows: Figure 4 As shown in the figure, the prepared catalyst has abundant L and B acid sites.
[0048] Example 2
[0049] The method was carried out according to Example 1, except that 2.4509 g (0.01 mol) (CH3COO)2Mn·4H2O and 4.9816 g (CH3COO)2Co·4H2O were weighed to prepare solution A, and the catalyst MnCo2O4 was obtained.
[0050] Example 3
[0051] The method was carried out according to Example 1, except that 3.6764 g (0.015 mol) (CH3COO)2Mn·4H2O and 3.7362 g (0.015 mol) (CH3COO)2Co·4H2O were weighed to prepare solution A, and the catalyst Mn was obtained. 1.5 Co 1.5 O4.
[0052] Example 4
[0053] The method was carried out according to Example 1, except that the concentration of the sulfuric acid solution was prepared to be 0.5 mol / L, resulting in catalysts SO4 / TiO2@Mn2CoO4 with different amounts of active components.
[0054] Example 5
[0055] The method was carried out according to Example 1, except that the impregnation time with sulfuric acid solution was 4 hours, resulting in catalysts SO4 / TiO2@Mn2CoO4 with different amounts of active components.
[0056] Example 6
[0057] The method was carried out according to Example 1, except that the impregnation time with sulfuric acid solution was 6 hours, resulting in catalysts SO4 / TiO2@Mn2CoO4 with different amounts of active components.
[0058] Example 7
[0059] The method was implemented according to Example 1, except that the impregnation time with sulfuric acid solution was 8 hours, resulting in catalysts SO4 / TiO2@Mn2CoO4 with different amounts of active components.
[0060] Example 8
[0061] The method was carried out according to Example 1, except that the impregnation time with sulfuric acid solution was 12 hours, resulting in catalysts SO4 / TiO2@Mn2CoO4 with different amounts of active components.
[0062] Test case
[0063] The catalytic regeneration rate of the catalysts obtained in the test examples; all of the above catalysts were brand new catalysts that had not undergone actual operation.
[0064] The catalyst activity testing method is as follows:
[0065] Before the desorption test, a mixture of 85 (v / v)% N2 and 15 (v / v)% CO2 (hereinafter referred to as the mixed gas) at a flow rate of 240 mL / min was bubbled into 100 mL of 30 wt% MEA solution for absorption. During the absorption process, the reading of the soap film flow meter was recorded every minute. The reaction ended when the reading of the soap film flow meter stopped changing. The CO2 loading in the saturated MEA was measured by acid hydrolysis. To avoid the influence of the absorption process on the desorption performance evaluation, the absorption time, absorption temperature, and absorption equipment were kept exactly the same for each absorption. The desorption process temperature was controlled at 98℃, the catalyst mass fraction was 1.25 wt%, and N2 was introduced into the flask at a flow rate of 200 mL / min. The desorbed CO2 was discharged from the flask outlet through a condenser. During the first 30 minutes of desorption, the reading of the soap film flow meter was recorded every minute. The desorption rate can be calculated using the following formula.
[0066]
[0067] Where, r d The desorption rate of the solution is mmol CO2 / min; Q1 and Q2 are the inlet and outlet gas flow rates, respectively, in L / min; n IL V represents the molar amount of absorbent in the solution, in mol. m The value is the molecular molar volume under standard conditions, 22.4 L / mol.
[0068] Test results are as follows Figure 5 As shown. From Figure 5 It can be seen that the Co-based composite catalyst prepared by the method described in this invention can significantly improve the regeneration performance of MEA aqueous solution at low temperature, and the regeneration rate can be increased by about 103%.
Claims
1. A method for preparing Co-based spinel materials by low-temperature regeneration of catalytically rich amine solutions, characterized in that, Includes the following steps: 1) Measure out deionized water and ethanol, mix them evenly, weigh out (CH3COO)2Co·4H2O and (CH3COO)2Mn·4H2O, add them to the solution, and stir until completely dissolved to obtain solution A; Anhydrous oxalic acid is dissolved in deionized water and mixed thoroughly; this solution is labeled as solution B. Once solution A is completely clear, solution B is introduced into solution A to obtain a mixed solution; 2) The mixed solution was stirred and aged, then centrifuged and washed. After drying, it was transferred to a muffle furnace and calcined in air to obtain a Co-based composite oxide catalyst. 3) Anhydrous ethanol and ammonia solution were mixed to obtain solution C. The Co-based composite oxide catalyst was uniformly dispersed in solution C, then transferred to a water bath, and tetrabutyl titanate was added dropwise to the solution. The mixture was stirred continuously, the precipitate was centrifuged, washed, dried, and then transferred to a muffle furnace for calcination in air atmosphere to obtain a core-shell structured Co-based composite oxide catalyst. 4) The core-shell structured Co-based composite oxide catalyst is impregnated in sulfuric acid solution, filtered, washed with water, and dried to obtain the Co-based spinel material for low-temperature regeneration of amine-rich solution.
2. The method for preparing Co-based spinel material by low-temperature regeneration of catalytically rich amine solution according to claim 1, characterized in that, In step 2), the mixed solution is stirred and aged for 12-15 hours.
3. The method for preparing Co-based spinel material by low-temperature regeneration of catalytically rich amine solution according to claim 1, characterized in that, In step 2), the conditions for centrifugal washing are: wash the precipitate with water 3 to 5 times and with ethanol 1 to 3 times.
4. The method for preparing Co-based spinel material by low-temperature regeneration of catalytically rich amine solution according to claim 1, characterized in that, In step 2), the drying conditions are: drying at 70~90℃ for 10~14 hours.
5. The method for preparing Co-based spinel material by low-temperature regeneration of catalytically rich amine solution according to claim 1, characterized in that, In step 2), calcination is carried out at 450~550℃ for 2~4 hours in an air atmosphere.
6. The method for preparing Co-based spinel material by low-temperature regeneration of catalytically rich amine solution according to claim 1, characterized in that, In step 3), solution C is transferred to a water bath at 35-55°C; Continue stirring for 20-24 hours; Drying conditions: Dry at 70~90℃ for 10~14 hours; Calcination conditions: Calcine at 450~550℃ in air for 2~4 hours.
7. The method for preparing Co-based spinel material by low-temperature regeneration of catalytically rich amine solution according to claim 1, characterized in that, In step 4), the molar concentration of the sulfuric acid solution is 0.5 mol / L to 1.5 mol / L; Immerse in sulfuric acid solution for 1-12 hours; Drying conditions: Dry at 70~90℃ for 10~14 hours.
8. The application of Co-based spinel material prepared by the preparation method according to any one of claims 1 to 7 through low-temperature regeneration of catalytically rich amine solution in carbon capture based on chemical absorption.