A method for preparing a calcium-based adsorbent based on supercritical CO2 extraction technology

Abstract

The application discloses a preparation method of a calcium-based adsorbent based on a supercritical CO2 extraction technology, adopts orange peel residues after supercritical CO2 extraction as a precursor template for preparing a calcium-based CO2 adsorbent, realizes optimization of a micro-pore structure of the calcium-based CO2 adsorbent, improves the adsorption capacity of the calcium-based CO2 adsorbent, and saves the step of continuous calcination in a conventional preparation method, so that the energy consumption required for preparation is reduced and the preparation rate is accelerated through combustion instead of calcination; and the orange peel residues are waste residues of the extraction process, have the advantages of excellent pore structure and low economic cost compared with conventional precursor templates; in addition, the calcium-based CO2 adsorbent is doped with yttrium nitrate and magnesium nitrate, which is beneficial to improving the sintering resistance and cycle stability of the calcium-based CO2 adsorbent, and greatly improving the CO2 adsorption performance of the calcium-based material; and the preparation method is simple and suitable for large-scale industrial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid adsorbent composition preparation, and particularly relates to a calcium-based adsorbent preparation method based on supercritical CO2 extraction technology. BACKGROUND

[0002] Under the situation of global warming, controlling the emission of greenhouse gases such as CO2 is of great significance, so that the carbon dioxide capture and storage technology (CCS) has developed rapidly. The CCS technology is to separate and capture CO2 emitted in the production process, and store the captured CO2 in a geological storage layer or inject it into the deep sea.

[0003] Among the many carbon dioxide capture technical solutions, the use of solid adsorbents to separate CO2 in flue gas has better economy than amine adsorption method. The calcium-based adsorbent in the solid adsorbent has a wide source and low price, and has a large adsorption capacity for CO2. Therefore, the calcium looping cycle carbonation / calcination method (CaL) for separating CO2 in flue gas has attracted more and more attention of researchers. However, it is found that the conversion rate of natural calcium-based adsorbent for adsorbing CO2 will decrease sharply with the increase of the number of cycles, which has a great influence on the economy and stability of the CaL technology, and to some extent, limits the large-scale industrial application of the CaL technology. In order to enhance and stabilize the adsorption capacity of the calcium-based adsorbent, the design of the precursor template and the metal doping modification of the calcium-based adsorbent are the research hotspots in the field of calcium-based adsorbent preparation at present. Therefore, how to obtain a calcium-based adsorbent with more stable adsorption capacity through the design of the precursor template and the metal doping modification is an urgent problem to be solved at present. SUMMARY

[0004] In view of the above shortcomings of the prior art, the purpose of the present application is to provide a calcium-based adsorbent preparation method based on supercritical CO2 extraction technology, which solves the technical problem of poor stability of the adsorption capacity of the calcium-based adsorbent at present, and achieves the effect of improving the stability of the calcium-based adsorbent.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0006] A calcium-based adsorbent preparation method based on supercritical CO2 extraction technology, comprising the following steps:

[0007] 1) supercritical CO2 extraction of orange peel and drying to obtain orange peel residue;

[0008] 2) dissolving and mixing soluble yttrium salt, soluble magnesium salt and soluble calcium salt to obtain a mixed solution;

[0009] 3) placing the orange peel residue in the mixed solution, and absorbing the mixed solution by the orange peel residue to obtain a calcination body;

[0010] 4) calcining the body to be calcined to self-ignite to obtain the calcium-based CO2 adsorbent.

[0011] Further, the step 1) comprises the following sub-steps:

[0012] 11) washing and drying the orange peel, and crushing the orange peel to obtain orange peel particles;

[0013] 12) putting the orange peel particles into an extraction kettle to perform supercritical CO2 extraction;

[0014] 13) filtering the extraction liquid, and collecting and drying the orange peel residues obtained by supercritical CO2 extraction of the orange peel particles, and taking the orange peel residues as a precursor template for preparing the calcium-based CO2 adsorbent.

[0015] Further, the step 12) is specifically: putting the orange peel particles with a mesh size of 30-40 into the extraction kettle, taking anhydrous ethanol as the entraining agent, setting the flow rate of the entraining agent to be 0.7-0.8 mL / min, the flow rate of CO2 to be 2.8-3.2 L / min, the extraction pressure to be 30-40 MPa, and the extraction temperature to be 35-40℃, and performing the extraction after reaching the set values.

[0016] Further, in the step 2), the concentrations of the soluble yttrium salt, the soluble magnesium salt and the soluble calcium salt in the mixed solution are all 2.40-2.60 mol / L, and the mass ratio of Y2O3, MgO and CaO in the calcium-based CO2 adsorbent obtained in the step 4) is 1:1:3.

[0017] Further, in the step 3), the solid-liquid ratio of the orange peel residues to the mixed solution is 1 g:6 mL-1 g:5 mL.

[0018] Further, in the step 4), the calcination temperature is 700-900℃, the heating rate of the calcination is 10℃ / min, and the calcination time is 5-10 min.

[0019] Further, the calcium-based CO2 adsorbent is used for adsorbing and separating carbon dioxide by the calcium-based adsorbent, and adsorbing carbon dioxide generated in a chemical looping reforming enhanced hydrogen production process.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] 1. The calcium-based adsorbent preparation method based on supercritical CO2 extraction technology, adopts the orange peel residue after supercritical CO2 extraction as the precursor template for preparing the calcium-based CO2 adsorbent, realizes the optimization of the micro-pore structure of the calcium-based CO2 adsorbent, improves the adsorption capacity of the calcium-based CO2 adsorbent, and is low in economic cost; in addition, the calcined body is self-ignited after short-time calcination of 5-10 min, the self-ignition of the calcined body is used to replace the continuous calcination in the conventional preparation method (the generation of CaO is realized by continuous calcination for 60-90 min in the conventional preparation method), and thus the energy consumption required for preparation is reduced, and the preparation rate is accelerated.

[0022] 2. The calcium-based adsorbent preparation method based on supercritical CO2 extraction technology, loads the materials for generating calcium oxide and metal additives on the orange peel residue through the impregnation method, so that the prepared calcium-based CO2 adsorbent has the two metal additives Y2O3 and MgO in addition to the main component CaO, and the sintering resistance and the cycle stability of the calcium-based CO2 adsorbent are improved, and the CO2 adsorption performance of the calcium-based material is greatly improved.

[0023] 3. The calcium-based adsorbent preparation method based on supercritical CO2 extraction technology is simple, suitable for large-scale industrial production, can be used for the calcium-based adsorbent adsorption method for capturing carbon dioxide and the chemical chain reforming hydrogen production strengthening combined process, and has the characteristics of high adsorption efficiency and good cycle stability. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A flow chart of a calcium-based adsorbent preparation method based on supercritical CO2 extraction technology according to an embodiment;

[0025] Figure 2 A comparison chart of the adsorption amounts of the calcium-based CO2 adsorbent prepared in the application and other adsorbents;

[0026] Figure 3 A comparison chart of the specific surface area, pore volume and average particle size of the calcium-based CO2 adsorbent prepared in the application and other adsorbents. DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Generally, the components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0028] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In the description of the present application, it needs to be explained that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation and cannot be understood as indicating or implying relative importance. In addition, the terms "horizontal", "vertical" and the like do not mean that the components must be absolutely horizontal or vertical, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined. In the description of the present application, it also needs to be explained that unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] Embodiment:

[0030] Please refer to Figure 1 A preparation method of calcium-based adsorbent based on supercritical CO2 extraction technology, the prepared calcium-based CO2 adsorbent is mainly used for calcium-based adsorbent adsorption separation of carbon dioxide and adsorption of carbon dioxide generated in the chemical chain reforming hydrogen enrichment process, the method comprises the following steps:

[0031] 1) The orange peel is subjected to supercritical CO2 extraction and dried to obtain orange peel residues, which are used as a precursor template for preparing a calcium-based CO2 adsorbent. The specific steps are as follows:

[0032] 11) The orange peel is washed, dried, and crushed to obtain orange peel particles.

[0033] 12) The orange peel particles are placed in an extraction kettle for supercritical CO2 extraction. Specifically, 30-40 mesh orange peel particles are placed in the extraction kettle, anhydrous ethanol is used as the entrainer, the flow rate of the entrainer is set to 0.7-0.8 mL / min, the flow rate of CO2 is set to 2.8-3.2 L / min, the extraction pressure is set to 30-40 MPa, and the extraction temperature is set to 35-40℃. After reaching the set values, extraction is carried out.

[0034] During implementation, the flow rate of the entrainer can be set to 0.7 L / min, 0.75 L / min, and 0.8 mL / min, the flow rate of CO2 can be set to 2.8 L / min, 3.0 L / min, and 3.2 L / min, the extraction pressure can be set to 30 MPa, 35 MPa, and 40 MPa, and the extraction temperature can be set to 35℃, 38℃, and 40℃.

[0035] 13) The extraction liquid is filtered out, and the orange peel residues obtained by supercritical CO2 extraction of the orange peel particles are collected and dried. The orange peel residues are used as a precursor template for preparing a calcium-based CO2 adsorbent.

[0036] 2) Dissolve and mix the soluble yttrium salt, the soluble magnesium salt, and the soluble calcium salt to obtain a mixed solution. The amounts of the soluble yttrium salt, the soluble magnesium salt, and the soluble calcium salt in the mixed solution are determined according to the mass ratio of Y2O3, MgO, and CaO in the calcium-based CO2 adsorbent to be prepared. The concentrations of the soluble yttrium salt, the soluble magnesium salt, and the soluble calcium salt are all 2.40-2.60 mol / L.

[0037] During implementation, the concentrations of the soluble yttrium salt, the soluble magnesium salt, and the soluble calcium salt can be 2.40 mol / L, 2.50 mol / L, and 2.60 mol / L. In this embodiment, the soluble yttrium salt and the soluble magnesium salt are yttrium nitrate and magnesium nitrate, respectively.

[0038] 3) The orange peel residues are placed in the mixed solution, and the orange peel residues absorb the mixed solution to obtain a calcination body. Specifically, the solid-liquid ratio of the orange peel residues to the mixed solution is 1 g:6 ml-1 g:5 ml. During implementation, the solid-liquid ratio of the orange peel residues to the mixed solution can be 1 g:5 ml, 1 g:5.5 ml, and 1 g:6 ml.

[0039] 4) calcining the calcining body to obtain the calcium-based CO2 adsorbent, specifically, the calcining temperature is 700~900℃, the calcining temperature rising rate is 10℃ / min, and the calcining time is 5~10 min; in the implementation, the calcining temperature can be 700℃, 750℃, 800℃, 850℃ and 900℃, and the calcining time can be 5 min, 7 min and 10 min; in this embodiment, the mass ratio of Y2O3, MgO and CaO in the prepared calcium-based CO2 adsorbent is 1:1:3.

[0040] The calcium-based adsorbent preparation method based on the supercritical CO2 extraction technology, the specific surface area, pore volume and average particle size of the calcium-based CO2 adsorbent prepared by the method of the present application and the calcium-based CO2 adsorbent prepared by the method of the present application but with yttrium and aluminum as the main metal additives are compared as shown in a, b and c in the following table. Figure 3 As shown in a, b and c in the following table, the specific surface area, pore volume and average particle size of the calcium-based CO2 adsorbent prepared by the method of the present application are all better; this is because the orange peel residue extracted by supercritical CO2 has good specific surface area and pore volume, and the plant fiber formed after extraction can be used as a biomass template to prepare a calcium-based CO2 adsorbent with high performance and high stability; not only the adsorption capacity of the calcium-based CO2 adsorbent is improved, but also the economic cost is low; in addition, the precursor template of orange peel residue can also assist combustion, and the calcining body is self-ignited after short-time calcining for 5~10 min, which replaces the continuous calcining in the conventional preparation method (the generation of CaO is realized by continuous calcining for 60~90 min in the conventional preparation method), which is conducive to reducing the energy consumption required for preparation and speeding up the preparation rate;

[0041] The materials for generating calcium oxide and metal additives are loaded on the orange peel residue by the impregnation method, that is, yttrium nitrate and magnesium nitrate are added to the mixed solution, so that the prepared calcium-based CO2 adsorbent has Y2O3 and MgO as two kinds of metal additives in addition to the main component CaO, and the adsorption capacity of the calcium-based CO2 adsorbent prepared by the method of the present application and the calcium-based CO2 adsorbent prepared by the method of the present application but with yttrium and aluminum as the main metal additives is compared as shown in the following table. Figure 2 As shown in the following table, the adsorption capacity and cyclic stability of the calcium-based CO2 adsorbent prepared by the method of the present application are both better; in addition, the calcium-based CO2 adsorbent prepared by the method of the present application with yttrium and magnesium as the main metal additives is also obviously better than the calcium-based CO2 adsorbent with yttrium and aluminum as the main metal additives; that is, with yttrium and magnesium as the main metal additives, it is conducive to improving the sintering resistance and cyclic stability of the calcium-based CO2 adsorbent, and greatly improving the CO2 adsorption performance of the calcium-based material; the preparation method is simple, and can be used for the calcium-based adsorbent adsorption method for capturing carbon dioxide and the chemical looping reforming and hydrogen production combined and coordinated process, and is suitable for large-scale industrial production.

[0042] Finally, it should be noted that the above examples are intended to illustrate the technical solutions of the present application but not to limit the technical solutions. Those of ordinary skill in the art should understand that modifications or equivalent replacements to the technical solutions of the present application can be made without departing from the purpose and scope of the technical solutions, and all should be covered within the scope of the claims of the present application.

Claims

1. A method for preparing calcium-based sorbents based on supercritical CO2 extraction technology, characterized by: The method comprises the following steps: 1) supercritical CO2 extraction of orange peel and drying to obtain orange peel residue; 2) dissolving and mixing soluble yttrium salt, soluble magnesium salt and soluble calcium salt to obtain a mixed solution; 3) placing the orange peel residue in the mixed solution, and absorbing the mixed solution by the orange peel residue to obtain a calcination body; 4) calcining the calcination body to obtain a calcium-based CO2 adsorbent; In step 4), the calcination temperature is 700-900℃, the calcination heating rate is 10℃ / min, and the calcination time is 5-10min; Step 1) comprises the following sub-steps: 11) washing and drying the orange peel, and crushing to obtain orange peel particles; 12) placing the orange peel particles in an extraction kettle for supercritical CO2 extraction; 13) filtering off the extraction liquid, collecting and drying the orange peel residue obtained by supercritical CO2 extraction of the orange peel particles, and taking the orange peel residue as a precursor template for preparing the calcium-based CO2 adsorbent; Step 12) specifically comprises: selecting 30-40 mesh orange peel particles, placing them in an extraction kettle, using anhydrous ethanol as a entrainer, setting the flow rate of the entrainer to 0.7-0.8mL / min, the flow rate of CO2 to 2.8-3.2L / min, the extraction pressure to 30-40MPa, and the extraction temperature to 35-40℃, and then performing extraction after reaching the set values.

2. The method for preparing calcium-based sorbent based on supercritical CO2 extraction technology according to claim 1, characterized in that: In step 2), the concentrations of the soluble yttrium salt, the soluble magnesium salt and the soluble calcium salt in the mixed solution are all 2.40-2.60mol / L, and the mass ratio of Y2O3, MgO and CaO in the calcium-based CO2 adsorbent obtained in step 4) is 1:1:

3.

3. The method for preparing calcium-based sorbent based on supercritical CO2 extraction technology according to claim 1, characterized in that: In step 3), the solid-liquid ratio of the orange peel residue to the mixed solution is 1g:6ml-1g:5ml.

4. Use of the calcium-based CO2 adsorbent according to any one of claims 1-3 in adsorption separation of carbon dioxide by calcium-based adsorbents and adsorption of carbon dioxide produced in a chemical looping reforming enhanced hydrogen production process.

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