Preparation method of carbon dioxide solid adsorption material and product thereof

Abstract

The invention relates to a preparation method of a carbon dioxide solid adsorption material and a product thereof, and the method comprises the following steps: mixing sieved fly ash and sodium hydroxide with deionized water according to a predetermined mass ratio to obtain a mixed slurry, stirring the mixed slurry, and carrying out solid-liquid separation after stirring to obtain desiliconized fly ash. Stirring and mixing the desiliconized fly ash with limestone powder, a pore forming agent and a binder to obtain an initial solid adsorption material; and carrying out molding treatment on the initial solid adsorption material, and calcining the molded solid adsorption material under a high-temperature condition to obtain the carbon dioxide solid adsorption material. The problem that the activity of a high-temperature calcium-based solid adsorption material is rapidly reduced along with the increase of the cycle index in related technologies is solved.

Description

Technical Field

[0001] The present application relates to the technical field of industrial carbon dioxide capture, and particularly to a preparation method and product of a carbon dioxide solid adsorption material. Background Art

[0002] The non-amine solid adsorption CO₂ capture technology enables the solid adsorption material to continuously capture CO₂ from flue gas through the reversible carbonation / regeneration reaction between the solid adsorption material and CO₂. Compared with the currently relatively mature organic amine solution absorption technology and solid pressure swing adsorption technology, this technology has the characteristics of strong adaptability, no corrosion, and no secondary pollution, and is more suitable for large-scale CO₂ capture. Among them, the solid adsorption material having high selectivity and adsorption capacity for CO₂ is also the key to the solid adsorption CO₂ capture technology.

[0003] Currently, there are many processes for preparing and synthesizing solid adsorption materials. However, when the solid adsorption CO₂ capture technology is applied on a large scale, the solid adsorption material has the problem of low activity. Summary of the Invention

[0004] Embodiments of the present application provide a preparation method and product of a carbon dioxide solid adsorption material, so as to at least solve the problem that the solid adsorption material has low activity when the solid adsorption CO₂ capture technology is applied on a large scale in the related art.

[0005] In a first aspect, embodiments of the present application provide a preparation method of a carbon dioxide solid adsorption material, and the method includes:

[0006] Mix fly ash after sieving treatment with sodium hydroxide according to a predetermined mass ratio with deionized water to obtain a mixed slurry, and the solid-liquid ratio of the mixed slurry is 300 g - 500 g / L; wherein, when the silica content in the fly ash ≤ 30%, the mass ratio of fly ash to sodium hydroxide is 3:1; when the silica content is greater than 30% and less than 50%, the mass ratio of the fly ash to the sodium hydroxide is 1.5 - 3:1; when the silica content ≥ 50%, the mass ratio of the fly ash to the sodium hydroxide is 1.5:1;

[0007] Heat and stir the mixed slurry, and perform solid-liquid separation after heat and stir to obtain desilicated fly ash;

[0008] Stir and mix the desilicated fly ash with limestone powder, pore-forming agent, and binder to obtain an initial solid adsorption material;

[0009] Perform shaping treatment on the initial solid adsorption material, and calcine the shaped solid adsorption material under high temperature conditions to obtain a carbon dioxide solid adsorption material.

[0010] In one embodiment, stirring the mixed slurry and performing solid-liquid separation after stirring to obtain desilicated fly ash includes:

[0011] Performing ultrasonic treatment on the mixed slurry for 10 min by an ultrasonic instrument under the temperature condition of 40 °C;

[0012] Performing hydrothermal stirring on the ultrasonically treated mixed slurry by a stirring device under the temperature condition of 60 - 100 °C, with a stirring time of 30 - 50 min and the rotation speed of the stirring device being 150 - 300 rpm;

[0013] Performing centrifugal solid-liquid separation on the mixed slurry after hydrothermal stirring;

[0014] Adding deionized water to wash the solid after the solid-liquid separation to obtain desilicated fly ash, wherein the conductivity of the deionized water is 200 - 10 μs.

[0015] In one embodiment, after stirring the mixed slurry and performing solid-liquid separation to obtain desilicated fly ash, the method further includes:

[0016] Mixing the liquid after solid-liquid separation with the liquid after washing to obtain a mixed liquid, adding calcium oxide to the mixed liquid and stirring to dissolve it, wherein the calcium oxide content is determined according to the silicon content in the mixed liquid, and the calcium-silicon molar ratio is 1.0 - 1.5:1;

[0017] Letting the stirred and dissolved mixed liquid stand and precipitate for 6 - 12 h and then performing solid-liquid separation, drying the separated solid at 40 - 60 °C for 6 - 8 h to obtain calcium silicate hydrate; the separated liquid is a sodium hydroxide solution, and the sodium hydroxide solution is used for desilicating the fly ash.

[0018] In one embodiment, in the process of stirring and mixing the desilicated fly ash with limestone powder, pore-forming agent, and binder, the blending ratio of the fly ash is 5 - 40%, the blending ratio of the limestone is 50 - 80%, the blending ratio of the pore-forming agent accounts for 5 - 10%, and the blending ratio of the binder is 5 - 10%.

[0019] In one embodiment, the forming treatment of the initial solid adsorbent material includes:

[0020] Performing extrusion and rounding operations on the initial solid adsorbent material to obtain a formed solid adsorbent material; or

[0021] Performing tabletting on the initial solid adsorbent material and crushing the solid adsorbent material after the tabletting treatment;

[0022] The sieving process is performed on the crushed solid adsorbent material to obtain a formed solid adsorbent material.

[0023] In one embodiment, the formed solid adsorbent material is calcined under high-temperature conditions to obtain a carbon dioxide solid adsorbent material, including:

[0024] The formed solid adsorbent material is prepared under the conditions of a drying temperature of 60 - 80 °C, a drying time of 6 - 12 h, a calcination temperature of 850 °C - 950 °C, and a calcination time of 2 - 6 h to obtain a carbon dioxide solid adsorbent material.

[0025] In one embodiment, before the fly ash after sieving treatment and sodium hydroxide are mixed with deionized water according to a predetermined mass ratio to obtain a mixed slurry, the method further includes:

[0026] The fly ash is sieved to obtain fly ash after sieving treatment;

[0027] The limestone is ground and the ground limestone is sieved to obtain limestone powder;

[0028] When the pore-forming agent and the binder are insoluble solids, the pore-forming agent and the binder are ground and sieved.

[0029] In one embodiment, the sieve mesh range in the sieving process is 150 - 200 mesh;

[0030] The particle size of the ground limestone is 80 - 110 μm, and the sieve mesh range in the sieving process of the limestone is 150 - 200 mesh;

[0031] The particle size of the ground pore-forming agent and the binder is 80 - 110 μm, and the sieve mesh range in the sieving process of the pore-forming agent and the binder is 150 - 200 mesh.

[0032] In one embodiment, the amount of desilication of the fly ash after desilication treatment is greater than 30% - 40%.

[0033] In a second aspect, the embodiments of the present application provide a carbon dioxide solid adsorbent material prepared according to the method described above.

[0034] The preparation method and product of a carbon dioxide solid adsorbent material provided by the embodiments of the present application at least have the following technical effects.

[0035] By mixing the sieved fly ash, sodium hydroxide, and deionized water according to a predetermined mass ratio, a mixed slurry is obtained, and the solid-liquid ratio of the mixed slurry is 300 g - 500 g / L; wherein, when the silica content in the fly ash ≤ 30%, the mass ratio of fly ash to sodium hydroxide is 3:1; when the silica content is greater than 30% and less than 50%, the mass ratio of the fly ash to the sodium hydroxide is 1.5 - 3:1; when the silica content ≥ 50%, the mass ratio of the fly ash to the sodium hydroxide is 1.5:1. Stir the mixed slurry, and perform solid-liquid separation after stirring to obtain the fly ash after desilication treatment. Stir and mix the desilicated fly ash with limestone powder, pore-forming agent, and binder to obtain an initial solid adsorbent material. Perform shaping treatment on the initial solid adsorbent material, dry the shaped solid adsorbent material, and calcine it under high-temperature conditions to obtain a carbon dioxide solid adsorbent material. This application uses fly ash as a carrier and limestone as a precursor, and blends a pore-forming agent and a binder to prepare a calcium-based solid adsorbent material, which not only realizes the transformation of waste into treasure, but also combines high activity and low cost, laying a foundation for the large-scale application of solid adsorption CO2 capture. It solves the problem of low activity of solid adsorbent materials in related technologies.

[0036] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more concise and understandable. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The illustrative embodiments and descriptions thereof of the present application are used to explain the present application and do not constitute an improper limitation of the present application.

[0038] In the drawings:

[0039] Figure 1 is a flowchart of a method for preparing a carbon dioxide solid adsorbent material shown according to an exemplary embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] In order to make the objectives, technical solutions, and advantages of the present application clearer, the present application will be described and explained below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0041] Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings. In addition, it can also be understood that although the efforts made in this development process may be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacturing, or production changes based on the technical content disclosed in the present application are only conventional technical means and should not be understood as the content disclosed in the present application being insufficient.

[0042] The mention of "embodiment" in this application means that the specific features, structures, or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those of ordinary skill in the art explicitly and implicitly understand that the embodiments described in the present application can be combined with other embodiments without conflict.

[0043] The non-amine solid adsorption CO2 capture technology captures CO2 from flue gas continuously through the reversible carbonation / regeneration reaction between the solid adsorption material and CO2. Compared with the currently more mature organic amine solution absorption technology and solid pressure swing adsorption technology, this technology has the characteristics of strong adaptability, no corrosion, and no secondary pollution, and is more suitable for large-scale CO2 capture, which is also the focus of research by scholars at home and abroad. Among them, the solid adsorption material has high selectivity and adsorption capacity for CO2, which is also the key to the solid adsorption CO2 capture technology.

[0044] In a first aspect, an embodiment of the present application provides a method for preparing a carbon dioxide solid adsorption material. Figure 1 It is a flowchart of a method for preparing a carbon dioxide solid adsorption material shown according to an exemplary embodiment. As Figure 1 shown, the method includes:

[0045] Step S101: Mix the sieved fly ash and sodium hydroxide according to a predetermined mass ratio with deionized water to obtain a mixed slurry, and the solid-liquid ratio of the mixed slurry is 300g - 500g / L.

[0046] Among them, when the silica content in the fly ash ≤ 30%, the mass ratio of fly ash to sodium hydroxide is 3:1; when the silica content is greater than 30% and less than 50%, the mass ratio of fly ash to sodium hydroxide is 1.5 - 3:1; when the silica content ≥ 50%, the mass ratio of fly ash to sodium hydroxide is 1.5:1.

[0047] Step S102: Stir the mixed slurry, and perform solid-liquid separation after stirring to obtain desilicated fly ash.

[0048] Step S103: Stir and mix the desilicated fly ash with limestone powder, pore-forming agent, and binder to obtain an initial solid adsorbent material.

[0049] Step S104: Perform shaping treatment on the initial solid adsorbent material, and calcine the shaped solid adsorbent material under high-temperature conditions to obtain a carbon dioxide solid adsorbent material.

[0050] In summary, this application uses fly ash as a carrier and limestone as a precursor, and mixes a pore-forming agent and a binder to prepare a calcium-based solid adsorbent material, which not only realizes waste utilization but also combines high activity and low cost, laying a foundation for the large-scale application of solid adsorption CO2 capture. It solves the problem of low activity of solid adsorbent materials in related technologies. The preparation method provided by the embodiments of this application will be described and introduced in detail below.

[0051] Step S101: Mix the sieved fly ash and sodium hydroxide with deionized water according to a predetermined mass ratio to obtain a mixed slurry, and the solid-liquid ratio of the mixed slurry is 300 g - 500 g / L.

[0052] Each ton of coal burned by a coal-fired unit will produce about 0.3 t of fly ash. The utilization rate of fly ash is low. Large-area accumulation in ash yards not only harms the environment and ecology but also causes waste of resources. Fly ash has a porous structure, and its main components are SiO2 and Al2O3 (the component ratio is above 60%). As dopants, SiO2 and Al2O3 can slow down the sintering of solid adsorbent materials and enhance the cycle stability. If fly ash is used as a raw material to participate in the preparation of solid adsorbent materials, it can not only realize waste utilization but also enhance the cycle stability of solid adsorbent materials.

[0053] Among them, when the silica content in fly ash ≤ 30%, the mass ratio of fly ash to sodium hydroxide is 3:1; when the silica content is greater than 30% and less than 50%, the mass ratio of fly ash to sodium hydroxide is 1.5 - 3:1; when the silica content ≥ 50%, the mass ratio of fly ash to sodium hydroxide is 1.5:1.

[0054] Optionally, the sieved fly ash and NaOH in Step S101 are dissolved in deionized water according to a certain ratio to obtain a mixed slurry, and the mass ratio of fly ash to NaOH needs to be determined according to the SiO2 content in fly ash.

[0055] When the SiO2 content in fly ash ≤ 30%, the mass ratio of fly ash to NaOH is taken as 3:1. A lower SiO2 content means more other active components (such as Al2O3) in fly ash, and a higher mass ratio of fly ash to NaOH (3:1) can ensure the full reaction of these fly ash components with NaOH.

[0056] When 30% < SiO2 content in fly ash < 50%, the mass ratio of fly ash to NaOH is 1.5 - 3:1. As the SiO2 content increases, the reaction activity of fly ash decreases. Appropriately reducing the mass ratio of fly ash to NaOH (1.5 - 3:1) can ensure the balance of the reaction and avoid waste of excessive NaOH.

[0057] When the SiO2 content in fly ash ≥ 50%, the mass ratio of fly ash to NaOH is taken as 1.5:1. The solid-liquid ratio of the mixed slurry is 300g - 500g / L, and 500g / L can be selected in this embodiment. Fly ash with a high SiO2 content has a low reaction activity, and a lower mass ratio of fly ash to NaOH (1.5:1) can reduce the dosage of NaOH and lower the production cost.

[0058] Step S101 ensures the efficient progress of the reaction by adjusting the mass ratio of fly ash to NaOH, improves the performance of the final material, and optimizes the adsorption capacity of the final material by adjusting the mass of fly ash according to the SiO2 content in fly ash.

[0059] In one embodiment, before step S101, the preparation method further includes:

[0060] Screen the fly ash to obtain the screened fly ash;

[0061] Grind the limestone and then screen the ground limestone to obtain limestone powder;

[0062] When the pore-forming agent and the binder are insoluble solids, grind and screen the pore-forming agent and the binder.

[0063] Among them, the screen range in the screening process is 150 - 200 mesh; the particle size of the ground limestone particles is 80 - 110μm, the screen range in the screening process of limestone is 150 - 200 mesh; the particle size of the ground pore-forming agent and binder is 80 - 110μm, and the screen range in the screening process of the pore-forming agent and binder is 150 - 200 mesh.

[0064] Optionally, before step S101, material preparation is carried out. The raw materials are prepared by using fly ash as the carrier and limestone as the precursor, and admixing pore-forming agents and binders. Among them, the fly ash is fine fly ash after being sieved by a sieve, and the optional range of the sieve is 150 - 200 mesh, and 200 mesh can be selected in this embodiment. The limestone is ground by a ball mill or other equipment with the same grinding function. In this embodiment, a ball mill can be selected. The ball mill grinds to a particle size of 80 - 110 μm, and 100 μm can be selected in this embodiment. Then it is sieved by a sieve, and the optional range of the sieve is 150 - 200 mesh, and 200 mesh can be selected in this embodiment. The pore-forming agent can be organic acids, organic alcohols, urea, cellulose, etc.; the binder is preferably epoxy resin. If the pore-forming agent or binder is an insoluble solid, it must be ground and sieved before use, and the optional range of the sieve is 150 - 200 mesh, and 200 mesh can be selected in this embodiment.

[0065] Step S101 ensures that the particle sizes of all raw materials are uniform through sieving and grinding treatments, increases the specific surface area and porosity of the material, thereby enhancing its CO2 adsorption capacity. Using fly ash as the carrier realizes the resource utilization of waste and reduces the production cost. Limestone and fly ash are both inexpensive and easily available raw materials, thus reducing the preparation cost.

[0066] Step S102: Stir the mixed slurry, and perform solid-liquid separation after stirring to obtain the desilicated fly ash.

[0067] Optionally, the mixed slurry is ultrasonically treated by an ultrasonic instrument for 10 min under the temperature condition of 40°C. The ultrasonically treated mixed slurry is hydrothermally stirred by a stirring device under the temperature condition of 60 - 100°C. The stirring time is 30 - 50 min, and the rotation speed of the stirring device is 150 - 300 rpm. Centrifugal solid-liquid separation is performed on the stirred mixed slurry. Deionized water is added to wash the solid after solid-liquid separation to obtain the desilicated fly ash.

[0068] It should be noted that the mixed slurry is ultrasonically treated before heating and stirring. The ultrasonic power can be selected from 200 - 600 W, and 600 W can be selected in this embodiment. The temperature is 40°C, and the ultrasonic treatment is for 10 min. Then the mixed slurry is hydrothermally stirred. The heating temperature is 60 - 90°C, the heating and stirring time is 30 - 50 min, and the rotation speed is 150 - 300 rpm. The purpose of adding the ultrasonic treatment link is to increase the rate of particle collision in the liquid phase through ultrasonic waves, increase the reaction speed, and greatly reduce the subsequent heating and stirring time.

[0069] In this way, the desilication amount of fly ash after desilication treatment is greater than 30%-40%. In this example, the optional desilication amount is greater than 35%. It should be noted that if the silicon content is too high, the surface area of the prepared solid adsorbent material will become smaller and the pore structure will be affected. Therefore, desilication treatment is required to increase the surface area of the solid adsorbent material and thus improve the activity of the solid adsorbent material.

[0070] Step S102 can effectively achieve the desilication treatment of fly ash by controlling the temperature, stirring time and rotation speed, reach the target of desilication amount greater than 30%, and improve the reaction activity and porosity of fly ash.

[0071] In one embodiment, after stirring the mixed slurry in step S102 and performing solid-liquid separation after stirring to obtain the desilicated fly ash, the method further includes:

[0072] Mix the liquid after solid-liquid separation with the liquid after washing to obtain a mixed liquid, and add calcium oxide to the mixed liquid and stir to dissolve it. Among them, the content of calcium oxide is determined according to the silicon content in the mixed liquid, and the calcium-silicon molar ratio is 1.0-1.5:1;

[0073] Let the stirred and dissolved mixed liquid stand and precipitate for 6-12 h and then perform solid-liquid separation. The separated solid is dried at 40-60 °C for 6-8 h to obtain calcium silicate hydrate; the separated liquid is sodium hydroxide solution, and the sodium hydroxide solution is used for the desilication treatment of fly ash.

[0074] Optionally, mix the liquid after solid-liquid separation with the liquid after washing to obtain a mixed liquid, and add an appropriate amount of calcium oxide to the mixed liquid and stir to dissolve it. The appropriate amount of calcium oxide content is added according to the silicon content in the mixed liquid, and the calcium-silicon molar ratio is controlled at 1.0-1.5:1. In this example, 1.2 is optional. Let the stirred and dissolved mixed liquid stand and precipitate for 6-12 h and then perform solid-liquid separation. The separation method is not limited, and centrifugal separation is preferred. The separated solid is dried at 40-60 °C for 6-8 h to obtain calcium silicate hydrate; the separated liquid is mainly NaOH solution and can be recycled for the subsequent pre-desilication treatment of fly ash.

[0075] It should be noted that calcium silicate hydrate can be used as an anti-caking agent or a porous carrier for other solid adsorbents. For example, by impregnating with alkaline carbonates such as NaCO3 and K2CO3 or alkaline nitrates such as NaNO3 and K2NO3 solutions and then drying, a low-temperature sodium-based or potassium-based solid adsorbent material can be prepared, which can be used for solid adsorption of CO2 capture.

[0076] By recycling sodium hydroxide, the recycling of resources is realized and the production cost is reduced. The by-product calcium silicate hydrate generated during the preparation process can be further used as an anti-caking agent or a porous carrier for low-temperature solid adsorbent materials.

[0077] Step S103: Stir and mix the desilicated fly ash with limestone powder, pore-forming agent, and binder to obtain the initial solid adsorbent material. Specifically, it includes:

[0078] Optionally, proportion and fully stir and mix the ground limestone powder, pore-forming agent, and binder with the desilicated fly ash. Proportion: The blending ratio of fly ash is 5 - 40%, optionally 10 - 20% in this embodiment; the blending ratio of limestone is 50 - 80%, optionally 70 - 80% in this embodiment; the blending ratio of pore-forming agent is 5 - 10%; the blending ratio of binder is 5 - 10%.

[0079] In step S103, SiO2 and Al2O3 in the fly ash can improve the surface activity of the material and enhance its chemical reactivity. Using fly ash as a carrier realizes the resource utilization of waste and reduces environmental pollution. Limestone decomposes into CaO at high temperature, and CaO can react with CO2 to form CaCO3, achieving efficient CO2 adsorption. A relatively high blending ratio of limestone can ensure a sufficiently high content of CaO in the material and improve the adsorption capacity. The pore-forming agent decomposes or volatilizes at high temperature to form pores, increasing the porosity of the material. The porous structure can provide more adsorption sites and improve the adsorption ability of the material. The binder can bond components such as fly ash, limestone powder, and pore-forming agent together to improve the strength of the material.

[0080] In one embodiment, step S104: Perform a shaping treatment on the initial solid adsorbent material, and calcine the shaped solid adsorbent material at a high temperature after drying to obtain a carbon dioxide solid adsorbent material.

[0081] The following operations can be performed for the shaping treatment of the initial solid adsorbent material:

[0082] Optionally, by the extrusion - spheronization method, the size of the adsorbent particles can be adjusted as needed to ensure uniform particle size and obtain a shaped solid adsorbent material.

[0083] Optionally, by the tabletting method, the initial solid adsorbent material can be pressed into sheets. Subsequently, through crushing and sieving of the sheet material, the size of the adsorbent particles can be controlled to ensure that the particle size meets the requirements and obtain a shaped solid adsorbent material.

[0084] Dry the shaped solid adsorbent material at a temperature of 60 - 80°C for 6 - 12 hours. The purpose is to remove the moisture in the material and ensure that no cracks and deformations occur during the high-temperature calcination process. Calcinate at a temperature of 850 - 950°C for 2 - 6 hours. The purpose is to fully activate the active components (such as CaO) in the material through high-temperature calcination to generate a highly active calcium-based solid adsorbent material.

[0085] In step S104, through forming, drying, and calcination treatments, the prepared calcium-based solid adsorbent material has the characteristics of high adsorption capacity and high activity, and can efficiently capture CO2. By using the extrusion-spheronization method and the tabletting and crushing method, the size of the adsorbent particles can be controlled to ensure uniform particle size.

[0086] In summary, a method for preparing a carbon dioxide solid adsorbent material provided by an embodiment of the present application includes mixing sieved fly ash and sodium hydroxide with deionized water according to a predetermined mass ratio to obtain a mixed slurry, and the solid-liquid ratio of the mixed slurry is 300 g - 500 g / L; wherein, when the silica content in the fly ash is ≤ 30%, the mass ratio of fly ash to sodium hydroxide is 3:1; when the silica content is greater than 30% and less than 50%, the mass ratio of fly ash to sodium hydroxide is 1.5 - 3:1; when the silica content ≥ 50%, the mass ratio of fly ash to sodium hydroxide is 1.5:1. Stir the mixed slurry, and perform solid-liquid separation after stirring to obtain desilicated fly ash. Stir and mix the desilicated fly ash with limestone powder, pore-forming agent, and binder to obtain an initial solid adsorbent material. Perform forming treatment on the initial solid adsorbent material, dry the formed solid adsorbent material, and calcine it at high temperature to obtain a carbon dioxide solid adsorbent material. The present application uses fly ash as a carrier and limestone as a precursor, and incorporates a pore-forming agent and a binder to prepare a calcium-based solid adsorbent material, which not only realizes waste utilization but also combines high activity and low cost, laying a foundation for the large-scale application of solid adsorption CO2 capture. It solves the problem of low activity of solid adsorbent materials in related technologies.

[0087] Beneficial effects of the present application: Using fly ash as a carrier and limestone as a precursor, adding an appropriate amount of pore-forming agent and binder to prepare a solid adsorbent material. Turning fly ash into a useful resource, with low raw material prices and simple preparation steps, making the preparation of solid adsorbent materials low-cost; no secondary pollution is generated during the preparation process, and the by-product calcium silicate hydrate can be further utilized, having good social, economic, and environmental benefits; the prepared calcium-based solid adsorbent material has high activity and good cycle stability; it provides an idea for the large-scale preparation of high-activity and low-cost solid adsorbent materials and lays a foundation for the large-scale application of solid adsorption CO2 capture.

[0088] In a second aspect, an embodiment of the present application provides a carbon dioxide solid adsorbent material prepared according to the above method. The prepared carbon dioxide solid adsorbent material has the characteristics of high adsorption capacity and high activity, and can efficiently capture CO2.

[0089] The following introduces the solution provided by the present application through comparative experimental data:

[0090] 1. Preparation of test samples:

[0091] (1) Fine fly ash was collected from a power plant in Hebei Province. The fly ash contained 50.37% SiO2 and 22.53% Al2O3, and also contained Fe2O3, CaO, MgO and other components.

[0092] (2) Fly ash was sieved through 200 mesh. According to the SiO2 content of 50.37%, 30 g of fly ash and 20 g of NaOH were dissolved in 100 ml of deionized water to prepare a mixed slurry. The mixed slurry was then subjected to ultrasonic pretreatment at 40°C / 10 min, and then subjected to hydrothermal stirring treatment at 90°C / 30 min. The mixture was then subjected to solid-liquid separation, washed with deionized water twice, and filtered to obtain a residue. The residue was dried at 105°C for 2 h to obtain the desiliconized fly ash.

[0093] (3) Analytically pure CaCO3 was used instead of limestone, and urea was selected as the pore-forming agent. The mass of CaCO3 was 8 g + desiliconized fly ash 2 g + urea 0.55 g. After thorough stirring, an appropriate amount of deionized water was added (solid-liquid mass ratio 7:3). Then, solid adsorption spherical particles (particle size range 0.3-0.6 mm) were prepared by extrusion-spheronization method, dried at 80°C for 8 h, and calcined at 850°C for 2 h.

[0094] 2. Preparation of comparative samples

[0095] Analytical pure CaCO3 was used to replace limestone, CaCO3 mass 10g + deionized water 3g, and solid adsorption spherical particles (particle size range 0.3-0.6mm) were prepared by extrusion-spheronization method, dried at 80℃ for 8h, and calcined at 850℃ for 2h.

[0096] 3. Test conditions

[0097] The test was carried out using a synchronous thermal analyzer. The carbonation conditions were 15% CO2+85% N2, 650°C, 15 min, and the calcination conditions were 100% N2, 850°C, 2 min.

[0098] 4. Test results:

[0099] (1) Test sample: Initial CO2 adsorption capacity is 0.55 g / g. After 30 cycles, the adsorption capacity is 0.376 g / g.

[0100] (2) Comparative sample: The initial CO2 adsorption capacity was 0.61 g / g, and the adsorption capacity after 30 cycles was 0.157 g / g.

[0101] 5. Analysis:

[0102] Although the initial CO2 adsorption capacity of the modified calcium-based solid adsorbent doped with desilicated fly ash is lower than that of the calcium-based solid adsorbent prepared from pure CaCO3, after 30 cycles of testing, the adsorption capacity of the prepared modified calcium-based solid adsorbent test sample is 2.4 times that of the comparative sample, which reflects excellent adsorption performance and cycle stability, and solves the problem that the activity of the high-temperature calcium-based solid adsorbent rapidly decreases with the increase of the number of cycles.

[0103] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0104] The above embodiments only represent several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for preparing a solid carbon dioxide adsorption material, characterized in that: The method comprises: The fly ash after screening is mixed with sodium hydroxide and deionized water according to a predetermined mass ratio to obtain a mixed slurry, wherein the solid-liquid ratio of the mixed slurry is 300g-500g / L; wherein, when the silicon dioxide content in the fly ash is ≤30%, the mass ratio of the fly ash to the sodium hydroxide is 3:1; when the silicon dioxide content is greater than 30% and less than 50%, the mass ratio of the fly ash to the sodium hydroxide is 1.5-3:1; when the silicon dioxide content is ≥50%, the mass ratio of the fly ash to the sodium hydroxide is 1.5:1; The mixed slurry is stirred, and solid-liquid separation is performed after stirring to obtain fly ash after desiliconization treatment; The desiliconized fly ash is mixed with limestone powder, a pore-forming agent and a binder to obtain an initial solid adsorption material; The initial solid adsorption material is subjected to a molding process, and the solid adsorption material after the molding process is calcined under high temperature conditions to obtain a solid carbon dioxide adsorption material.

2. The method according to claim 1, characterized in that The mixed slurry is stirred and solid-liquid separation is performed after stirring to obtain fly ash after desiliconization, comprising: The mixed slurry is subjected to ultrasonic treatment for 10 minutes at a temperature of 40° C. by using an ultrasonicator; The mixed slurry after ultrasonic treatment is hydrothermally stirred by a stirring device at a temperature of 60-100° C., the stirring time is 30-50 min, and the speed of the stirring device is 150-300 rpm; Performing centrifugal solid-liquid separation on the mixed slurry after hydrothermal stirring; After the solid-liquid separation, deionized water is added to wash the solid to obtain fly ash after desiliconization, wherein the conductivity of the deionized water is 200-10 μs.

3. The method according to claim 2, characterized in that After the mixed slurry is stirred and solid-liquid separation is performed after stirring to obtain fly ash after desiliconization, the method further comprises: The liquid after solid-liquid separation is mixed with the liquid after washing to obtain a mixed liquid, and calcium oxide is added to the mixed liquid and stirred to dissolve, wherein the content of the calcium oxide is determined according to the silicon content in the mixed liquid, and the calcium-silicon molar ratio is 1.0-1.5:1; The mixed liquid after stirring and dissolving is allowed to stand for 6-12 hours and then solid-liquid separation is performed. After separation, the solid is dried at 40-60° C. for 6-8 hours to obtain hydrated calcium silicate. The liquid after separation is a sodium hydroxide solution, and the sodium hydroxide solution is used to desiliconize the fly ash.

4. The method according to claim 1, characterized in that When the fly ash after desiliconization is stirred and mixed with limestone powder, pore former and binder, the fly ash is blended in a proportion of 5-40%, the limestone is blended in a proportion of 50-80%, the pore former is blended in a proportion of 5-10%, and the binder is blended in a proportion of 5-10%.

5. The method according to claim 1, characterized in that The forming process of the initial solid adsorption material comprises: Extruding and spheronizing the initial solid adsorption material to obtain a shaped solid adsorption material; or The initial solid adsorption material is subjected to tableting, and the solid adsorption material subjected to tableting is crushed; The crushed solid adsorption material is sieved to obtain a formed solid adsorption material.

6. The method according to claim 1, characterized in that The solid adsorption material after the molding process is calcined under high temperature conditions to obtain a solid carbon dioxide adsorption material, comprising: The solid adsorption material after the molding treatment is prepared under the conditions of a drying temperature of 60-80° C., a drying time of 6-12 hours, a calcination temperature of 850° C.-950° C., and a calcination time of 2-6 hours to obtain a solid carbon dioxide adsorption material.

7. The method according to claim 1, characterized in that Before mixing the fly ash and sodium hydroxide after the sieving process with deionized water according to a predetermined mass ratio to obtain a mixed slurry, the method further comprises: Screening the fly ash to obtain screened fly ash; Grinding the limestone, and sieving the ground limestone to obtain limestone powder; When the pore former and the binder are insoluble solids, the pore former and the binder are ground and sieved.

8. The method according to claim 7, characterized in that The mesh size of the sieve is 150-200 mesh. The particle size of the limestone after the grinding process is 80-110 μm, and the sieve range of the limestone during the sieving process is 150-200 mesh; The particle size of the ground pore-forming agent and the binder is 80-110 μm, and the sieve range of the pore-forming agent and the binder during the sieving process is 150-200 meshes.

9. The method according to claim 2, characterized in that: The desiliconization amount of the fly ash after the desiliconization treatment is greater than 30%-40%.

10. A solid carbon dioxide adsorption material, characterized in that: The carbon dioxide solid adsorption material is prepared by the method according to any one of claims 1 to 9.

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