Preparation method of HPW-coated CeO2 / HZSM-5 catalyst for catalyzing desorption of CO2 in amine absorption liquid

Abstract

The invention discloses a preparation method of a HPW-CeO2 / HZSM-5 catalyst for catalyzing desorption of CO2 in amine absorption liquid, and the method comprises the following steps: dipping a roasted HZSM-5 molecular sieve in a cerium-based precursor aqueous solution, carrying out ultrasonic water bath to evaporate excessive moisture, drying and roasting an obtained solid product to prepare a CeO2 / HZSM-5 precursor; dipping the CeO2 / HZSM-5 precursor in a phosphotungstic acid (HPW) solution, and carrying out ultrasonic water bath until no excessive water exists; and drying and roasting to obtain the HPW-coated CeO2 / HZSM-5 catalyst. The method for preparing the catalyst is simple, dipping loading of multiple elements can be achieved, then the CO2 catalytic desorption performance in the amine absorption liquid is regulated and controlled, and the low-temperature desorption efficiency of the amine absorption liquid is improved.

Description

Technical Field

[0001] The present invention relates to the field of environmental technology, and in particular to a method for preparing a HPW@CeO2 / HZSM-5 catalyst for catalyzing the desorption of CO2 in an amine absorption liquid. Background Art

[0002] With the large-scale combustion of fossil fuels, CO2 emissions continue to rise, making the global greenhouse effect increasingly serious. Currently, carbon capture, utilization, and storage (CCUS) technology, as an important way to control carbon emissions, has huge application potential. Among the many technologies, organic amine absorption is currently the most mature CO2 capture technology. However, this technology has significant drawbacks. The energy consumption of amine absorption liquid regeneration is generally high, accounting for 60% to 70% of the total energy consumption of the entire carbon capture process. This has become a key factor restricting the large-scale industrial application of this technology.

[0003] Solid acid catalysts are widely used in the regeneration process of CO2-rich amine solutions. This type of catalyst can accelerate CO2 desorption, thereby reducing regeneration temperature and energy consumption. Studies have shown that catalysts such as molecular sieves, super-strong solid acids and metal oxides can significantly improve the regeneration efficiency of CO2-rich amine solutions. For example, CN109316903A discloses a method for preparing a mesoporous solid acid-base catalyst for desorption of CO2-rich amine solutions, which can reduce energy consumption by about 32.5% during the catalytic desorption process. In addition, CN110681413B discloses a method for preparing a nano-FeZr@composite molecular sieve catalyst for desorption of CO2-rich amine solutions. The solid acid catalyst prepared by this method can reduce energy consumption by about 33%. However, the various types of solid acid catalysts currently used still have limitations in terms of energy-saving effects and cannot meet industrial requirements. In order to further reduce the regeneration energy consumption of CO2-rich amine solution, lower the CO2 capture cost and improve the economic feasibility of the organic amine absorption method, the present invention uses a simple ultrasonic impregnation method to prepare a new HPW@CeO2 / HZSM-5 catalyst, which is applied to the regeneration process of CO2-rich amine solution, which helps promote the industrial development of CCUS technology. Summary of the Invention

[0004] The invention discloses a method for preparing an HPW@CeO2 / HZSM-5 catalyst for catalyzing the desorption of CO2 in an amine absorption liquid, aiming to reduce the energy consumption of catalyzing the desorption of CO2.

[0005] The present invention provides a method for preparing a HPW@CeO2 / HZSM-5 catalyst for catalyzing the desorption of CO2 from an amine absorption liquid, comprising the following steps:

[0006] (1) calcining HZSM-5 at 400-600° C. for 1-3 h, adding it to a water-soluble cerium salt solution after cooling, and evaporating the water completely in an ultrasonic water bath at 60-90° C., collecting the solid product, drying it at 60-100° C. for 12-20 h, and calcining the dried solid product at 400-600° C. for 3-6 h to obtain a CeO2 / HZSM-5 precursor. The HZSM-5 molecular sieve has a silicon-aluminum ratio of one or more of 25, 38, 50, 80, 100, and 200, preferably a silicon-aluminum ratio of 25, the cerium salt is one or more of cerium nitrate, cerium chloride, cerium sulfate, and cerium acetate, preferably cerium nitrate, and the mass ratio of the cerium salt to the HZSM-5 is 1:10-6:10.

[0007] (2) The CeO2 / HZSM-5 precursor was dispersed in pure water, and phosphotungstic acid was added. The mixture was ultrasonically heated in a water bath at 60-90°C until the water was completely evaporated. The solid product was collected and dried at 60-100°C for 12-20 hours. The dried solid product was calcined at 200-400°C for 3-6 hours to obtain an HPW@CeO2 / HZSM-5 catalyst. The mass ratio of the phosphotungstic acid to CeO2 / HZSM-5 was 1:10-6:10.

[0008] The present invention uses a simple ultrasound-assisted impregnation method to prepare HPW@CeO2 / HZSM-5 catalyst. Its SEM characterization and energy spectrum scanning analysis results show that HZSM-5 co-loaded with CeO2 and HPW still maintains a complete crystal morphology. EDX element mapping confirms that characteristic elements such as Ce and W are uniformly dispersed on the support surface. NH3-TPD characterization analysis shows that the HPW@CeO2 / HZ catalyst has a large number of strong acid sites, showing a significant acid advantage. Py-IR characterization results show that the introduction of phosphotungstic acid effectively improves the The active protons derived from the surface heteropolyacid structure of the acid synergistically interact with the hydroxyl groups of the molecular sieve to effectively promote the CO2 desorption process. The method provided by the present invention is simple, scientific, and effective. It can achieve the loading of multiple elements and heteropolyacids and regulate the surface acidity of the catalyst, and has high application value in the field of catalytic CO2 desorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is the SEM characterization analysis result of the product prepared in Example 3;

[0010] Figure 2 This is the energy spectrum scanning analysis result of the product prepared in Example 3;

[0011] Figure 3 This is the NH3-TPD characterization analysis result of the product prepared in Example 3;

[0012] Figure 4This is the Py-IR characterization analysis result of the product prepared in Example 3;

[0013] Figure 5 This is the test result of the product prepared in Example 1 catalyzing the desorption of CO2 from an amine solution;

[0014] Figure 6 This is the test result of the product prepared in Example 2 catalyzing the desorption of CO2 from an amine solution;

[0015] Figure 7 This is the test result of the product prepared in Example 3 catalyzing the desorption of CO2 from an amine solution;

[0016] Figure 8 This is the test result of the product prepared in Example 4 catalyzing the desorption of CO2 from amine solution. DETAILED DESCRIPTION

[0017] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0018] Example 1

[0019] This embodiment provides a method for synthesizing a HPW@CeO2 / HZSM-5 catalyst, specifically:

[0020] (1) Take 30g of HZSM-5 molecular sieve with a silicon-aluminum ratio of 25 and calcine it at 500℃ for 2h;

[0021] (2) 1.5 g of cerium nitrate was dissolved in 15 mL of pure water, 5.0 g of calcined HZSM-5 molecular sieve was added to the cerium nitrate solution, excess water was evaporated in an ultrasonic water bath at 80 °C, and the solid product was collected;

[0022] (3) drying the product obtained in step (2) at 100° C. for 12 h, and calcining at 500° C. for 4 h to obtain a CeO2 / HZSM-5 precursor;

[0023] (4) Disperse 5.0 g of CeO2 / HZSM-5 precursor in pure water, dilute to 15 mL, add 0.5 g of phosphotungstic acid, evaporate excess water in an ultrasonic water bath at 80 °C, and collect the solid product;

[0024] (5) The product obtained in step (4) was dried at 100°C for 12 h and calcined at 300°C for 4 h to obtain HPW@CeO2 / HZSM-5 catalyst.

[0025] Example 2

[0026] This embodiment provides a method for synthesizing a HPW@CeO2 / HZSM-5 catalyst, specifically:

[0027] (1) Take 30g of HZSM-5 molecular sieve with a silicon-aluminum ratio of 25 and calcine it at 500℃ for 2h;

[0028] (2) 1.5 g of cerium nitrate was dissolved in 15 mL of pure water, 5.0 g of calcined HZSM-5 molecular sieve was added to the cerium nitrate solution, excess water was evaporated in an ultrasonic water bath at 80 °C, and the solid product was collected;

[0029] (3) drying the product obtained in step (2) at 100° C. for 12 h, and calcining at 500° C. for 4 h to obtain a CeO2 / HZSM-5 precursor;

[0030] (4) Disperse 5.0 g of CeO2 / HZSM-5 precursor in pure water, dilute to 15 mL, add 1.0 g of phosphotungstic acid, evaporate excess water in an ultrasonic water bath at 80 °C, and collect the solid product;

[0031] (5) The product obtained in step (4) was dried at 100°C for 12 h and calcined at 300°C for 4 h to obtain HPW@CeO2 / HZSM-5 catalyst.

[0032] Example 3

[0033] This embodiment provides a method for synthesizing a HPW@CeO2 / HZSM-5 catalyst, specifically:

[0034] (1) Take 30g of HZSM-5 molecular sieve with a silicon-aluminum ratio of 25 and calcine it at 500℃ for 2h;

[0035] (2) 1.5 g of cerium nitrate was dissolved in 15 mL of pure water, 5.0 g of calcined HZSM-5 molecular sieve was added to the cerium nitrate solution, excess water was evaporated in an ultrasonic water bath at 80 °C, and the solid product was collected;

[0036] (3) drying the product obtained in step (2) at 100° C. for 12 h, and calcining at 500° C. for 4 h to obtain a CeO2 / HZSM-5 precursor;

[0037] (4) Disperse 5.0 g of CeO2 / HZSM-5 precursor in pure water, dilute to 15 mL, add 1.5 g of phosphotungstic acid, evaporate excess water in an ultrasonic water bath at 80 °C, and collect the solid product;

[0038] (5) The product obtained in step (4) was dried at 100°C for 12 h and calcined at 300°C for 4 h to obtain HPW@CeO2 / HZSM-5 catalyst.

[0039] Figure 1This is the SEM characterization analysis result of the product prepared in Example 3. The results show that CeO2 and HPW are co-loaded on the HZSM-5 molecular sieve, and the composite material can still well maintain the original complete crystal structure characteristics of the HZSM-5 molecular sieve, without obvious lattice distortion or crystal structure destruction.

[0040] Figure 2 This is the energy spectrum scanning analysis result of the product prepared in Example 3. The results show that characteristic elements such as Ce and W are highly uniformly dispersed on the surface of the HZSM-5 carrier. This uniform distribution characteristic can effectively increase the surface exposure of CeO2 and phosphotungstic acid active sites, providing more active centers for the catalytic reaction.

[0041] Figure 3 The NH3-TPD characterization analysis results of the product prepared in Example 3 show that the catalyst surface presents abundant strong acid sites, and the density of strong acid sites is significantly higher than that of HZSM-5, which provides a more favorable acidic environment for proton transfer and activation of reactant molecules in the catalytic reaction.

[0042] Figure 4 The Py-IR characterization analysis results of the product prepared in Example 3 show that the loading of phosphotungstic acid can significantly enhance the surface The strong interaction between the active protons generated by phosphotungstic acid and the hydroxyl groups of the HZSM-5 molecular sieve framework significantly improves the CO2 desorption efficiency.

[0043] Example 4

[0044] This embodiment provides a method for synthesizing a HPW@CeO2 / HZSM-5 catalyst, specifically:

[0045] (1) Take 30g of HZSM-5 molecular sieve with a silicon-aluminum ratio of 25 and calcine it at 500℃ for 2h.

[0046] (2) 1.5 g of cerium nitrate was dissolved in 15 mL of pure water, 5.0 g of calcined HZSM-5 molecular sieve was added to the cerium nitrate solution, excess water was evaporated in an ultrasonic water bath at 80 °C, and the solid product was collected.

[0047] (3) The product obtained in step (2) was dried at 100°C for 12 h and calcined at 500°C for 4 h to obtain a CeO2 / HZSM-5 precursor.

[0048] (4) Disperse 5.0 g of CeO2 / HZSM-5 precursor in pure water, dilute to 15 mL, add 2.5 g of phosphotungstic acid, evaporate excess water in an ultrasonic water bath at 80 °C, and collect the solid product.

[0049] (5) The product obtained in step (4) was dried at 100°C for 12 h and calcined at 300°C for 4 h to obtain HPW@CeO2 / HZSM-5 catalyst.

Claims

1. A method for preparing a HPW@CeO2 / HZSM-5 catalyst for catalyzing the desorption of CO2 from an amine absorption liquid, characterized in that: The catalyst is composed of an HZSM-5 molecular sieve carrier, CeO2 and phosphotungstic acid. The preparation method of the catalyst comprises the following steps: (1) calcining HZSM-5 molecular sieve for 1 to 3 hours at a calcination temperature of 400 to 600°C; (2) adding the HZSM-5 molecular sieve calcined in step (1) to a water-soluble cerium salt solution, ultrasonically evaporating the solution in a water bath at 60-90° C. until the water is completely dried, collecting the solid product, drying the solid product at 60-100° C. for 12-20 h, and calcining the dried solid product at 400-600° C. for 3-6 h to obtain a CeO2 / HZSM-5 precursor; (3) dispersing the CeO2 / HZSM-5 precursor obtained in step (2) in pure water, adding phosphotungstic acid, and evaporating the water completely in an ultrasonic water bath at 60-90°C, collecting the solid product, drying it at 60-100°C for 12-20h, and calcining the dried solid product at 200-400°C for 3-6h to obtain the HPW@CeO2 / HZSM-5 catalyst; The mass ratio of the cerium salt to the HZSM-5 molecular sieve is 1:10 to 6:10, and the mass ratio of phosphotungstic acid to CeO2 / HZSM-5 is 1:10 to 6:

10.

2. The method for preparing the catalyst according to claim 1, wherein The silicon-aluminum ratio of the HZSM-5 molecular sieve in step (1) is one or more of 25, 38, 50, 80, 100 and 200.

3. The method for preparing the catalyst according to claim 1, wherein The water-soluble cerium salt in step (2) is one or more of cerium nitrate, cerium chloride, cerium sulfate and cerium acetate.

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