Preparation method of porous calcium-based heat storage microspheres
Porous calcium-based heat storage microspheres are directly prepared by dissolving calcium salt, cerium salt and zirconium salt in deionized water, and then adding inorganic carbonate solution dropwise to precipitate, drying and calcining, which solves the problem of high cost of preparing porous spherical calcium-based heat storage materials in the prior art, and realizes an efficient and low-cost preparation method.
Patent Information
- Application Number
- CN202510180386.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-19
- Publication Date
- 2025-05-23
AI Technical Summary
The prior art is difficult to directly prepare porous spherical calcium-based heat storage materials, and it requires extrusion rounding and the use of organic carbon sources as templates, which increases the cost of material synthesis.
Porous calcium-based heat storage microspheres are directly obtained by dissolving soluble calcium, cerium and zirconium salts in deionized water to form a mixed solution, and then precipitate in the inorganic carbonate solution dropwise, and finally dried and calcined.
A convenient one-step preparation of cerium-zirconium modified calcium-based heat storage spheres with micro-nano porous structures is achieved, reducing the cost of material synthesis and improving the preparation efficiency.
Smart Images
Figure CN120025792A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for preparing a heat storage material, and belongs to the technical field of heat storage materials. Background Art
[0002] The calcium cycle based on calcium-based thermal storage materials is a solar energy storage technology based on calcium carbonate (CaCO 3 ) and calcium oxide (CaO) to achieve heat storage and release. 3 It has become the preferred material for calcium recycling technology due to its abundant raw materials, low price, non-toxicity and high energy density.
[0003] Calcium circulation technology is usually carried out in a fluidized bed reactor in industry. Making calcium-based heat storage materials into spherical particles is conducive to their fluidization and can be better applied to fluidized bed reactors. At present, the main method is to first prepare powdered calcium-based heat storage materials, and then use extrusion-spheronization operations to prepare spherical particles. At the same time, in order to obtain loose and porous calcium-based microspheres and improve heat and mass transfer during the cyclic reaction process, templates such as glucose and cellulose are often added during the particle preparation process, which increases the synthesis cost of the material. Therefore, how to prepare porous calcium-based microspheres efficiently and at low cost through simple methods is an urgent problem to be solved in calcium circulation technology. Summary of the invention
[0004] In view of the above-mentioned defects of the prior art, the present invention provides a method for preparing porous calcium-based heat storage microspheres, which solves the problem that the prior art cannot directly prepare porous spherical calcium-based heat storage materials but requires extrusion and spheronization and uses an organic carbon source as a template for preparation.
[0005] The technical solution of the present invention is as follows: A method for preparing porous calcium-based heat storage microspheres, comprising the steps of:
[0006] Step 1, dissolving a soluble calcium salt, a soluble cerium salt and a soluble zirconium salt in deionized water to obtain a mixed solution, wherein the molar ratio of cerium ions to zirconium ions in the mixed solution is 1:(1-5);
[0007] Step 2, adding the mixed solution dropwise into a soluble inorganic carbonate solution to fully precipitate calcium ions, cerium ions and zirconium ions to obtain a suspension;
[0008] Step 3, stirring the suspension and centrifuging it to obtain the precipitate and wash it;
[0009] Step 4: Place the precipitate in an oven for drying and then calcine to obtain porous calcium-based heat storage microspheres.
[0010] Furthermore, when the mixed solution is added dropwise into the soluble inorganic carbonate solution, the dropping speed is such that the volume of the mixed solution added dropwise per minute is no more than 1% of the volume of the soluble inorganic carbonate solution.
[0011] Furthermore, the molar concentration of the soluble inorganic carbonate solution is 10 to 50 times the total molar concentration of cerium ions, zirconium ions and calcium ions in the mixed solution.
[0012] Furthermore, the molar ratio of cerium ions to zirconium ions in the mixed solution is 1:(1.4-4.2).
[0013] Furthermore, the molar ratio of the sum of cerium ions and zirconium ions to calcium ions in the mixed solution is 1:(20-25).
[0014] Furthermore, the precipitate is rinsed with deionized water before being dried until the conductivity of the rinse liquid is less than 10 μS / cm.
[0015] Furthermore, the drying temperature is 100 to 150° C., and the drying time is 12 to 24 hours.
[0016] Furthermore, the calcination temperature is 750-900° C., and the calcination time is 0.5-4 hours.
[0017] Furthermore, the heating rate during the calcination is 1 to 5°C / min.
[0018] Furthermore, the particle size of the porous calcium-based heat storage microspheres is 15 to 30 μm.
[0019] Compared with the prior art, the advantages of the technical solution provided by the present invention are:
[0020] The present invention is a convenient one-step method for preparing cerium-zirconium modified calcium-based heat storage beads with a micro-nano porous structure. Calcium-based heat storage beads can be directly obtained without the need to prepare powders first and then synthesize spherical particles. The synthesis method is simple and easy to operate. In addition, in the particle preparation process, there is no need to add templates such as glucose and cellulose, which effectively reduces the synthesis cost of the material. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is the SEM image (20 μm) of the sample prepared in Example 1 of the present invention.
[0022] Figure 2 This is the SEM image (2 μm) of the sample prepared in Example 1 of the present invention.
[0023] Figure 3 This is the EDX image of the sample prepared in Example 1 of the present invention.
[0024] Figure 4 This is the SEM image (2 μm) of the sample prepared in Comparative Example 1 of the present invention.
[0025] Figure 5 This is the SEM image (2 μm) of the sample prepared in Comparative Example 2 of the present invention.
[0026] Figure 6 This is the SEM image (2 μm) of the sample prepared in Comparative Example 3 of the present invention.
[0027] Figure 7 This is the SEM image (2 μm) of the sample prepared in Comparative Example 4 of the present invention.
[0028] Figure 8 This is the SEM image (2 μm) of the sample prepared in Comparative Example 5 of the present invention.
[0029] Fig. 9 This is a comparison chart of the heat storage performance of the samples prepared in Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 of the present invention. DETAILED DESCRIPTION
[0030] The present invention is further described below in conjunction with examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading this description, various equivalent modifications to this description by those skilled in the art fall within the scope defined by the claims attached to this application.
[0031] Example 1
[0032] Weigh 27.642g K 2 CO 3 , dissolved in 100 mL of deionized water to obtain a K solution with a molar concentration of 2 mol / L 2 CO 3 solution. Weigh 0.022g Ce(NO 3 ) 3 6H 2 O, 0.060g Zr(NO 3 ) 4 ·5H 2 O and 0.979g Ca(NO 3 ) 2 ·4H 2 O was dissolved in 50 mL of deionized water to obtain a mixed solution of calcium salt, cerium salt and zirconium salt.
[0033] The mixed solution of calcium salt, cerium salt and zirconium salt was slowly dripped into K 2 CO 3Solution, control the flow rate to 1mL / min, so that the calcium ions, cerium ions and zirconium ions are fully precipitated to obtain a suspension. The suspension was stirred at room temperature for 2h, then centrifuged to obtain a precipitate, and the precipitate was rinsed with deionized water 5 times. The conductivity of the last rinse was less than 10μS / cm. The precipitate was placed in an oven for drying at a temperature of 120°C and a drying time of 12h. The dried sample was sent to a muffle furnace for calcination at a temperature of 850°C, a calcination time of 2h, and a calcination heating rate of 2°C / min. After calcination, cerium-zirconium modified porous calcium-based heat storage microspheres can be obtained. The SEM image of the sample is shown below. Figure 1 and Figure 2 As shown in Figure 2, the particle size of the porous calcium-based heat storage microspheres is 15 to 30 μm. Figure 3 As shown, it can be seen that the calcium, cerium and zirconium elements in the sample are evenly distributed.
[0034] Example 2
[0035] Weigh 13.821g K 2 CO 3 , dissolved in 100 mL of deionized water to obtain a K solution with a molar concentration of 1 mol / L 2 CO 3 solution. Weigh 0.0188g Ce(NO 3 ) 3 6H 2 O, 0.0778g Zr(NO 3 ) 4 ·5H 2 O and 1.128g Ca(NO 3 ) 2 ·4H 2 O was dissolved in 50 mL of deionized water to obtain a mixed solution of calcium salt, cerium salt and zirconium salt. The subsequent preparation steps were the same as those in Example 1, and porous calcium-based heat storage microspheres with a particle size of 15 to 30 μm were obtained.
[0036] Example 3
[0037] Weigh 138.21g K 2 CO 3 , dissolved in 100 mL of deionized water to obtain a K solution with a molar concentration of 10 mol / L 2 CO 3 solution. Weigh 0.078g Ce(NO 3 ) 3 6H 2 O, 0.108g Zr(NO 3 ) 4 ·5H 2 O and 2.348 g Ca(NO3 ) 2 ·4H 2 O was dissolved in 50 mL of deionized water to obtain a mixed solution of calcium salt, cerium salt and zirconium salt. The subsequent preparation steps were the same as those in Example 1, and porous calcium-based heat storage microspheres with a particle size of 15 to 30 μm were obtained.
[0038] Example 4
[0039] Weigh 27.642g K 2 CO 3 , dissolved in 100 mL of deionized water to obtain a K solution with a molar concentration of 2 mol / L 2 CO 3 solution. Weigh 0.022g Ce(NO 3 ) 3 6H 2 O, 0.060g Zr(NO 3 ) 4 ·5H 2 O and 0.979g Ca(NO 3 ) 2 ·4H 2 O was dissolved in 50 mL of deionized water to obtain a mixed solution of calcium salt, cerium salt and zirconium salt.
[0040] The calcium, cerium and zirconium mixed solution was slowly dripped into the K 2 CO 3 Solution, control the flow rate to 1mL / min, and obtain a suspension. Stir the suspension at room temperature for 2h, then centrifuge to obtain a precipitate, and rinse the precipitate with deionized water until the conductivity of the last rinse is less than 10μS / cm. Place the precipitate in an oven for drying at a temperature of 100°C and a drying time of 24h. Send the dried sample to a muffle furnace for calcination at a temperature of 750°C, a calcination time of 4h, and a calcination heating rate of 1°C / min. After calcination, cerium-zirconium modified porous calcium-based heat storage microspheres can be obtained.
[0041] Example 5
[0042] Weigh 27.642g K 2 CO 3 , dissolved in 100 mL of deionized water to obtain a K solution with a molar concentration of 2 mol / L 2 CO 3 solution. Weigh 0.022g Ce(NO 3 ) 3 6H 2 O, 0.060g Zr(NO 3 ) 4 ·5H 2O and 0.979g Ca(NO 3 ) 2 ·4H 2 O was dissolved in 50 mL of deionized water to obtain a mixed solution of calcium salt, cerium salt and zirconium salt.
[0043] The calcium, cerium and zirconium mixed solution was slowly dripped into the K 2 CO 3 Solution, control the flow rate to 1mL / min, and obtain a suspension. Stir the suspension at room temperature for 2h, then centrifuge to obtain a precipitate, and rinse the precipitate with deionized water until the conductivity of the last rinse is less than 10μS / cm. Place the precipitate in an oven for drying at a temperature of 150°C and a drying time of 15h. Send the dried sample to a muffle furnace for calcination at a temperature of 900°C, a calcination time of 0.5h, and a calcination heating rate of 5°C / min. After calcination, cerium-zirconium modified porous calcium-based heat storage microspheres can be obtained.
[0044] Comparative Example 1
[0045] No Ce(NO) was added during the synthesis process. 3 ) 3 6H 2 O and Zr(NO 3 ) 4 ·5H 2 O.
[0046] Weigh 27.642g K 2 CO 3 , dissolved in 100 mL of deionized water to obtain a K solution with a molar concentration of 2 mol / L 2 CO 3 Solution. Weigh 2.11 g Ca(NO 3 ) 2 ·4H 2 O, dissolved in 50 mL of deionized water to obtain Ca(NO 3 ) 2 Solution.
[0047] Ca(NO 3 ) 2 The solution was slowly added drop by drop into K 2 CO 3Solution, control the flow rate to 1mL / min, and obtain a suspension. Stir the suspension at room temperature for 2h, then centrifuge to obtain a precipitate, and rinse the precipitate with deionized water 5 times until the conductivity of the last rinse is less than 10μS / cm. Place the precipitate in an oven for drying at a temperature of 120°C and a drying time of 12h. Send the dried sample to a muffle furnace for calcination at a temperature of 850°C, a calcination time of 2h, and a calcination heating rate of 2°C / min. After calcination, a carrier-free modified calcium-based heat storage material can be obtained. The SEM image of the sample is shown below. Figure 4 shown.
[0048] Comparative Example 2
[0049] No Zr(NO) was added during the synthesis process. 3 ) 4 ·5H 2 O.
[0050] Weigh 27.642g K 2 CO 3 , dissolved in 100 mL of deionized water to obtain a K solution with a molar concentration of 2 mol / L 2 CO 3 solution. Weigh 0.126 g Ce(NO 3 ) 3 6H 2 O and 1.895g Ca(NO 3 ) 2 ·4H 2 O was dissolved in 50 mL of deionized water to obtain a mixed solution of calcium and cerium.
[0051] The calcium and cerium mixed solution was slowly dripped into the K 2 CO 3 Solution, control the flow rate to 1mL / min, and obtain a suspension. Stir the suspension at room temperature for 2h, then centrifuge to obtain a precipitate, and rinse the precipitate with deionized water 5 times until the conductivity of the last rinse is less than 10μS / cm. Place the precipitate in an oven for drying at a temperature of 120°C and a drying time of 12h. Send the dried sample to a muffle furnace for calcination at a temperature of 850°C, a calcination time of 2h, and a calcination heating rate of 2°C / min. After calcination, a cerium-modified calcium-based heat storage material can be obtained. The SEM image of the sample is shown below. Figure 5 shown.
[0052] Comparative Example 3
[0053] No Ce(NO) was added during the synthesis process. 3 ) 3 6H 2 O.
[0054] Weigh 27.642 g of K 2 CO 3 , dissolve it in 100 mL of deionized water to obtain a K 2 CO 3 solution with a molar concentration of 2 mol / L. Weigh 0.174 g of Zr(NO 3 ) 4 ·5H 2 O and 1.895 g of Ca(NO 3 ) 2 ·4H 2 O respectively, dissolve them in 50 mL of deionized water to obtain a mixed solution of calcium and zirconium.
[0055] Slowly and dropwise add the mixed solution of calcium and zirconium into the K 2 CO 3 solution using a syringe pump, control the flow rate at 1 mL / min to obtain a suspension. Stir the suspension at room temperature for 2 h, then centrifuge it to obtain a precipitate, and rinse the precipitate with deionized water 5 times until the conductivity of the last rinse solution is lower than 10 μS / cm. Place the precipitate in an oven for drying, the drying temperature is 120 °C, and the drying time is 12 h. Send the dried sample into a muffle furnace for calcination, the calcination temperature is 850 °C, the calcination time is 2 h, and the heating rate of calcination is 2 °C / min. After calcination, the zirconium-modified calcium-based heat storage material can be obtained, and the SEM image of the sample is as shown in Figure 6 .
[0056] Comparative Example 4
[0057] Weigh 13.821 g of K 2 CO 3 , dissolve it in 100 mL of deionized water to obtain a K 2 CO 3 solution with a molar concentration of 1 mol / L. Weigh 0.0337 g of Ce(NO 3 ) 3 ·6H 2 O, 0.0232 g of Zr(NO 3 ) 4 ·5H 2 O and 0.758 g of Ca(NO 3 ) 2 ·4H 2 O respectively, dissolve them in 50 mL of deionized water to obtain a mixed solution of calcium salt, cerium salt and zirconium salt. In this comparative example, the molar ratio of cerium ions to zirconium ions in the mixed solution is 1:0.7. The subsequent preparation steps are the same as those in Example 1 to obtain the zirconium-modified calcium-based heat storage material, and the SEM image of the sample is as shown in Figure 7 .
[0058] Comparative Example 5
[0059] Weigh 13.821g K 2 CO 3 , dissolved in 100 mL of deionized water to obtain a K solution with a molar concentration of 1 mol / L 2 CO 3 solution. Weigh 0.0130 g Ce(NO 3 ) 3 6H 2 O, 0.0720g Zr(NO 3 ) 4 ·5H 2 O and 0.978g Ca(NO 3 ) 2 ·4H 2 O, dissolved in 50 mL of deionized water to obtain a mixed solution of calcium salt, cerium salt and zirconium salt. The molar ratio of cerium ion to zirconium ion in the mixed solution in this comparative example is 1:5.6. The subsequent preparation steps are the same as in Example 1 to obtain a zirconium-modified calcium-based heat storage material. The SEM image of the sample is as follows: Figure 8 shown.
[0060] The samples prepared in Example 1 and Comparative Examples 1, 2, and 3 were subjected to a heat storage performance cycle test. The specific test method is to carry out a cycle experiment in a fixed bed reactor, and the calcination conditions are N 2 atmosphere, kept at 880℃ for 20min, the carbonation condition was in CO 2 atmosphere, and kept at 850℃ for 15min. By switching the reaction atmosphere, the calcination and carbonation process of the absorbent was achieved. With the help of a precision analytical balance, the mass of the sample after calcination and carbonation in different cycle reactions was obtained. The initial mass of the sample m 0 , the mass m of the sample after the nth cycle calcination reaction 1 and the mass m of the sample after the nth cycle of carbonation reaction 2 , the CO of the sample is calculated 2 Adsorption amount = (m 2 -m 1 ) / m 0 (Unit: g CO2 / g 吸收剂 The result is as follows. Fig. 9 As shown, it can be seen that the sample prepared in Example 1 has a slightly better cycle performance than the sample prepared in Comparative Example 2 while obtaining a porous spherical morphology, and is far better than Comparative Example 1 and Comparative Example 3.
Claims
1. A method for preparing porous calcium-based heat storage microspheres, characterized in that: Includes steps: Step 1, dissolving a soluble calcium salt, a soluble cerium salt and a soluble zirconium salt in deionized water to obtain a mixed solution, wherein the molar ratio of cerium ions to zirconium ions in the mixed solution is 1:(1-5); Step 2, adding the mixed solution dropwise into a soluble inorganic carbonate solution to fully precipitate calcium ions, cerium ions and zirconium ions to obtain a suspension; Step 3, stirring the suspension and centrifuging it to obtain the precipitate and wash it; Step 4: Place the precipitate in an oven for drying and then calcine to obtain porous calcium-based heat storage microspheres.
2. The method for preparing porous calcium-based heat storage microspheres according to claim 1, characterized in that: When the mixed solution is added dropwise into the soluble inorganic carbonate solution, the dropping speed is such that the volume of the mixed solution added dropwise per minute is no more than 1% of the volume of the soluble inorganic carbonate solution.
3. The method for preparing porous calcium-based heat storage microspheres according to claim 1, characterized in that: The molar concentration of the soluble inorganic carbonate solution is 10 to 50 times the total molar concentration of cerium ions, zirconium ions and calcium ions in the mixed solution.
4. The method for preparing porous calcium-based heat storage microspheres according to claim 1, characterized in that: The molar ratio of cerium ions to zirconium ions in the mixed solution is 1:(1.4-4.2).
5. The method for preparing porous calcium-based heat storage microspheres according to claim 1, characterized in that: The molar ratio of the sum of cerium ions and zirconium ions to calcium ions in the mixed solution is 1:(20-25).
6. The method for preparing porous calcium-based heat storage microspheres according to claim 1, characterized in that: The obtained precipitate was rinsed with deionized water before drying until the conductivity of the rinse solution was lower than 10 μS / cm.
7. The method for preparing porous calcium-based heat storage microspheres according to claim 1, characterized in that: The drying temperature is 100-150° C., and the drying time is 12-24 hours.
8. The method for preparing porous calcium-based heat storage microspheres according to claim 1, characterized in that: The calcination temperature is 750-900° C., and the calcination time is 0.5-4 hours.
9. The method for preparing porous calcium-based heat storage microspheres according to claim 1, characterized in that: The heating rate during the calcination is 1-5°C / min.
10. The method for preparing porous calcium-based heat storage microspheres according to claim 1, characterized in that: The particle size of the porous calcium-based heat storage microspheres is 15 to 30 μm.