Carbon dioxide adsorbent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of adsorption separation, in particular to a carbon dioxide adsorbent and a preparation method and application thereof. The carbon dioxide adsorbent provided by the invention comprises an inner core and a reinforced shell covering at least part of the surface of the inner core, the inner core comprises at least one of a metal oxide, a basic salt, a molecular sieve or a porous carbon material; the reinforced shell is of a pore channel structure, and the reinforced shell is made of inorganic non-metallic materials. The preparation method of the carbon dioxide adsorbent comprises the steps that an adsorbent precursor is subjected to forming treatment, an inner core is obtained, and the inner core comprises at least one of metal oxide, basic salt, a molecular sieve or a porous carbon material; mixing the inner core, the pore-forming agent and the reinforced shell material to obtain a mixture; the mixture is subjected to mechanical granulation treatment, at least part of the surface of the inner core is coated with the reinforced shell material, then calcination treatment is conducted, and the carbon dioxide adsorbent is obtained. The mechanical strength and wear resistance of the adsorbent can be improved, and the adsorption rate is increased.

Description

Technical Field

[0001] The present invention relates to the field of adsorption separation technology, and in particular to carbon dioxide adsorption separation for use in vehicles. Specifically, it relates to a carbon dioxide adsorbent, a preparation method thereof, and an application thereof. Background Art

[0002] At present, solid adsorbents used for carbon dioxide adsorption include calcium-based adsorbents, lithium-based adsorbents, porous physical adsorbents, etc. Among them, calcium-based adsorbents have become a carbon dioxide capture material with broad application prospects due to their advantages such as wide source of raw materials, low price, fast adsorption rate, and high theoretical carbon dioxide adsorption capacity. After multiple cycles of high-temperature adsorption and desorption, calcium-based adsorbents are prone to sintering, agglomeration, and structural collapse. In order to improve this problem, related technologies mainly improve the sintering resistance and mechanical stability at the powder level. However, in actual industrial carbon dioxide absorption or capture conditions, shaped adsorbent particles are usually required. In actual use, shaped adsorbent particles have the problem of poor mechanical strength and wear resistance index, which leads to a large amount of breakage or wear of the adsorbent particles to produce a large amount of powder, reduced adsorption performance and stability, poor reusability of the adsorbent particles in actual use, serious loss, and poor economic benefits.

[0003] Therefore, how to ensure that the carbon dioxide adsorbent particles have good mechanical strength without affecting their adsorption performance has become a technical problem that needs to be solved urgently in related fields. Summary of the Invention

[0004] In light of this, the present invention aims to address, at least to some extent, one of the technical problems in the related art. To this end, the present invention provides a carbon dioxide adsorbent, a preparation method, and applications thereof. These materials can alleviate the problems of poor mechanical strength and wear resistance of shaped adsorbent particles used for carbon dioxide adsorption, thereby ensuring good mechanical strength while maintaining adsorption performance.

[0005] In order to solve the above technical problems, this application is implemented as follows: According to one aspect of the present application, an embodiment of the present application provides a carbon dioxide adsorbent, comprising a core and a reinforced shell covering at least a portion of a surface of the core; The core comprises at least one of a metal oxide, an alkaline salt, a molecular sieve or a porous carbon material; The reinforced shell has a pore structure, and the reinforced shell material includes an inorganic non-metallic material.

[0006] In addition, the carbon dioxide adsorbent according to the present application may also have the following additional technical features: In some embodiments, the inorganic non-metallic material includes at least one of cement, bentonite or silica.

[0007] In some embodiments, the inner core comprises at least one of a calcium-based adsorbent, a magnesium-based adsorbent, a sodium-based adsorbent, a potassium-based adsorbent, a molecular sieve, or a porous carbon material.

[0008] In some embodiments, the average particle size of the core is in the range of 0.1 mm to 10 mm.

[0009] In some embodiments, the thickness of the reinforced shell is 0.1 mm to 5 mm.

[0010] In some embodiments, the specific surface area of the carbon dioxide adsorbent is 10m 2 / g~20m 2 / g.

[0011] In some embodiments, the pore volume of the carbon dioxide adsorbent is 0.08 cm 3 / g~0.15cm 3 / g.

[0012] In some embodiments, the average pore size of the pore structure of the reinforced shell in the carbon dioxide adsorbent is 25 nm to 35 nm.

[0013] According to another aspect of the present application, an embodiment of the present application provides a method for preparing a carbon dioxide adsorbent, the method comprising: forming an adsorbent precursor to obtain a core, wherein the core comprises at least one of a metal oxide, an alkaline salt, a molecular sieve, or a porous carbon material; The core, the pore-forming agent and the reinforcing shell material are mixed to obtain a mixture; the reinforcing shell material comprises an inorganic non-metallic material; The mixture is subjected to mechanical granulation treatment so that the reinforced shell material covers at least a portion of the surface of the core, and then subjected to calcination treatment to obtain the carbon dioxide adsorbent.

[0014] In some embodiments, the step of obtaining the kernel satisfies at least one of the following characteristics: (1) The adsorbent precursor includes at least one of a calcium precursor, a magnesium precursor, a sodium precursor, a potassium precursor, a molecular sieve precursor, or a porous carbon material precursor; (2) The average particle size of the adsorbent precursor is 50 mesh to 800 mesh; (3) The average particle size of the core is in the range of 0.1 mm to 10 mm; (4) The molding process includes at least one of spheronization, extrusion molding or tableting.

[0015] In some embodiments, the calcium precursor includes at least one of calcium hydroxide, calcium acetate, calcium nitrate, or calcium carbonate.

[0016] In some embodiments, the step of obtaining a mixture satisfies at least one of the following characteristics: (1) The pore-forming agent comprises at least one of cellulose, starch or polyvinyl pyrrolidone; (2) The inorganic non-metallic material includes at least one of cement, bentonite or silica; (3) The mass ratio of the pore-forming agent to the reinforcing shell material is 1:5 to 5:1; (4) The mass ratio of the core and the reinforced shell material is 10 to 2:1; (5) The mixing method includes at least one of ball milling, mechanical mixing or air milling.

[0017] In some embodiments, the mechanical granulation treatment includes a spheronization treatment, and the spheronization speed of the spheronization treatment is 10 rpm to 500 rpm, and the spheronization time is 1 min to 30 min.

[0018] In some embodiments, the calcination temperature is 650° C. to 950° C., the calcination time is 0.5 h to 2 h, and the calcination atmosphere includes air.

[0019] According to another aspect of the present application, an embodiment of the present application provides an application of a carbon dioxide adsorbent, wherein the carbon dioxide adsorbent includes the aforementioned carbon dioxide adsorbent, and / or includes the carbon dioxide adsorbent prepared by the aforementioned preparation method; the carbon dioxide adsorbent is used in a vehicle.

[0020] The implementation of the technical solution of the present invention has at least the following beneficial effects: The carbon dioxide adsorbent provided herein has a core-shell structure, comprising an inner core and a reinforced outer shell covering at least a portion of the inner core. The inner core comprises at least one of a metal oxide, an alkaline salt, a molecular sieve, or a porous carbon material. The reinforced outer shell has a pore structure and is made of an inorganic non-metallic material. Thus, by forming a reinforced outer shell with a pore structure on the surface of the inner core, the loss of active ingredients in the adsorbent core due to wear is effectively reduced, improving reusability, enhancing mechanical strength and wear resistance, and preventing particle breakage caused by volume expansion within the adsorbent core, thereby enhancing structural stability. The reinforced outer shell has abundant pores, allowing carbon dioxide gas to quickly enter the inner core, thereby increasing the adsorption rate.

[0021] Additional aspects and advantages of the present application will be given in part in the following description and in part will become obvious from the following description or will be learned through practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Shown is a structural schematic diagram of a carbon dioxide adsorbent provided by the present invention.

[0023] Figure 2 Shown is a schematic flow chart of a method for preparing a carbon dioxide adsorbent provided by the present invention.

[0024] Description of reference numerals: 100-core; 200-Reinforced shell; 210-Channel structure. DETAILED DESCRIPTION

[0025] The present application will be further described below with reference to specific examples. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application.

[0026] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range or the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0027] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0028] As mentioned in the background, existing modifications of carbon dioxide (CO2) adsorbents, such as calcium-based CO2 adsorbents, have been limited to the powder stage, focusing on improving the adsorption performance of the powder. However, in practice, shaped adsorbent particles have more applications. During use, shaped adsorbent particles are subject to crushing and abrasion due to factors such as extrusion, collision, and thermal shock, resulting in large amounts of powder, which seriously affects the performance and recyclability of the adsorbent. Therefore, while maintaining adsorption performance, it is necessary to improve the mechanical strength and wear resistance of the adsorbent particles. However, existing modifications of CO2 adsorbents still have certain shortcomings. For example, patent publication number CN112275251A discloses a method for mass production of doped and modified calcium-based CO2 adsorbent pellets. The method has a large number of preparation steps and complex operations, making it unsuitable for large-scale industrial production. Furthermore, the numerous chemical materials used, including binders, peptizers, and extrusion aids, increase costs. The preparation process requires large amounts of deionized water for dissolution and washing, and involves multiple drying and calcination steps, consuming significant energy in actual production. For another example, the preparation method of acid-modified Zr-doped calcium-based CO2 adsorbent beads disclosed in the patent with publication number CN118122265A, the sol-gel method used in its preparation, also has the problem of many steps and complicated operation, and the stirring, drying and other links in the sol-gel method usually require a lot of time, which is not suitable for large-scale mass production. In addition, in this method, the acid-modified reagent is added to the kneader together with the original powder for stirring and kneading, which may cause corrosion to the kneader and other equipment. The maximum crushing strength of the adsorbent particles in the example of this method is only 1.93N, which is difficult to meet most application scenarios. For another example, the patent with publication number CN118002067A discloses a calcium-based adsorbent and its preparation method, in which the added binder and biomass material are relatively large in proportion, which will reduce the proportion of effective adsorption components in the adsorbent to a certain extent, thereby reducing the adsorption capacity of the adsorbent. For example, the patent with publication number CN118719024B discloses a core-shell structure carbon dioxide adsorbent, which consists of a hollow silica shell layer and an internal UiO-66-NH2 active component with adsorption activity; the prepared adsorbent is a powder, and its core-shell structure is the core-shell structure of nanopowder particles at the microscopic level, which is difficult to meet most application scenarios.

[0029] In view of this, in practical applications, existing molded carbon dioxide adsorbent particles suffer from poor mechanical strength and wear resistance, which reduces adsorption performance and stability. Through extensive research, the inventors of this application have provided a carbon dioxide adsorbent, its preparation method, and its application, which can effectively alleviate these problems. A description of the specific technical solution is provided below.

[0030] First, as Figure 1As shown, in some embodiments, a carbon dioxide adsorbent is provided, which includes a core 100 and a reinforced shell 200 coated on at least a portion of the surface of the core 100; the core 100 includes at least one of a metal oxide, an alkaline salt, a molecular sieve or a porous carbon material; the reinforced shell 200 has a pore structure 210, and the reinforced shell material includes an inorganic non-metallic material.

[0031] The provided carbon dioxide adsorbent has a core-shell structure, with a coating layer, i.e., a reinforced shell 200, disposed on the surface of the core 100. It should be noted that, in this application, the term "coating" is not limited to direct coating but also includes indirect coating. For example, the coating layer (reinforced shell 200) may coat the core 100 with no other structure between the coating layer and the outer surface of the core 100, or with one or more layers of other structures between the coating layer and the outer surface of the core 100. Preferably, no other structure between the coating layer and the outer surface of the core 100 is present.

[0032] The reinforced shell 200 is formed or coated on at least a portion of the surface of the core 100, protecting or improving the core 100. This can be used to alleviate the poor mechanical strength and wear resistance of the molded carbon dioxide adsorbent particles, ensuring adsorption performance and improving structural stability. The reinforced shell 200 is formed or coated on at least a portion of the surface of the core 100. This means that the reinforced shell 200 can completely encapsulate the core 100 within the reinforced shell 200, or it can only coat a portion of the outer surface of the core 100. In other words, the reinforced shell 200 can completely coat the core 100 or only coat a portion of the surface of the core 100, preferably completely.

[0033] The inventors of this application have fully considered the inherent defects of existing molded carbon dioxide adsorbent particles and innovatively used a core-shell structure. The core 100 can be a metal oxide such as calcium oxide particles, and the reinforced shell 200 is a reinforced shell material with a pore structure 210. This ensures that the adsorbent particles have good mechanical strength while not affecting their adsorption performance. In detail: In a preferred embodiment, during the preparation of the carbon dioxide adsorbent, a reinforcing shell material is mixed with a pore-forming agent. A reinforcing shell layer is formed on the core particles through a spheronization method. The thickness of the reinforcing shell layer can be controlled by controlling conditions such as spheronization time and speed. The provision of this reinforcing shell layer ensures that the adsorbent particles have high mechanical strength and wear resistance. The pore-forming agent added during the preparation process forms pores after calcination, which, while reinforcing the shell 200 functions, ensures that gas can smoothly enter the core 100 for adsorption.

[0034] The carbon dioxide adsorbent particles have a high adsorption effective component content, which can bring about a higher adsorption capacity.

[0035] The reinforced shell 200 in the carbon dioxide adsorbent has abundant pores, which can allow CO2 gas to quickly enter the interior and increase the adsorption rate.

[0036] In carbon dioxide adsorbents, some adsorbent materials undergo volume changes during the adsorption process. For example, the volume expansion of CaCO3 formed after CaO adsorption is significant. The reinforced outer shell 200 of the present invention effectively prevents particle breakage caused by volume expansion within the adsorbent core, thereby improving structural stability. Furthermore, the encapsulation of the reinforced outer shell 200 effectively reduces the loss of active ingredients in the adsorbent core due to wear, thereby enhancing reusability. Furthermore, the present invention effectively alleviates the issues of poor mechanical strength and wear resistance associated with molded carbon dioxide adsorbent particles, ensuring adsorption performance and improving structural stability.

[0037] In the carbon dioxide adsorbent of the present application, the core 100 includes any one or more combinations of metal oxides, alkaline salts, molecular sieves, or porous carbon materials. That is, the core 100 can be a physical adsorbent such as a molecular sieve or a porous carbon material, or a chemical adsorbent such as a metal oxide or an alkaline salt, or a combination of a physical adsorbent and a chemical adsorbent. The metal oxide can be, for example, calcium oxide, or magnesium oxide, or a mixture of calcium oxide and magnesium oxide. The alkaline salt can be, for example, a sodium-containing alkaline salt, or a potassium-containing alkaline salt, or a mixture of a sodium-containing alkaline salt and an alkali-containing alkaline salt. The porous carbon material can be, for example, a carbon material such as activated carbon or carbon nanotubes.

[0038] In a preferred embodiment, the core 100 is a metal oxide, such as calcium oxide and / or magnesium oxide. Due to the mechanical strength and wear resistance issues of existing calcium-based adsorbents, calcium oxide is a more preferred core 100 in the present invention. In other words, the carbon dioxide adsorbent can be a calcium-based adsorbent, but the present invention is not limited thereto. For example, if existing magnesium-based adsorbents have similar issues, magnesium oxide can also be used.

[0039] In some embodiments, the core 100 includes, but is not limited to, any one or more of a calcium-based adsorbent, a magnesium-based adsorbent, a sodium-based adsorbent, a potassium-based adsorbent, a molecular sieve, or a porous carbon material. The calcium-based adsorbent may include calcium oxide, the magnesium-based adsorbent may include magnesium oxide, the sodium-based adsorbent may include sodium hydroxide or sodium carbonate, and the potassium-based adsorbent may include potassium hydroxide or potassium carbonate.

[0040] Preferably, the core 100 is selected from one or both of calcium oxide and magnesium oxide.

[0041] It is more preferred that the core 100 of the present invention is selected from calcium oxide, but it is not limited to this. That is, the core 100 of the carbon dioxide adsorbent, that is, the adsorbent core particle component is not necessarily calcium oxide and its precursor powder, but can also be magnesium oxide, molecular sieve or other composite carbon dioxide adsorbent spherical particles, and there is no specific method for granulating the core particles.

[0042] In the carbon dioxide adsorbent of the present application, the reinforcing shell material includes an inorganic non-metallic material. The use of inorganic non-metallic material as the reinforcing shell material has the characteristics of high hardness, chemical inertness, and high temperature resistance. It can improve the mechanical strength and wear resistance of the carbon dioxide adsorbent, which is beneficial to improving the structural stability of the overall particles of the carbon dioxide adsorbent, thereby ensuring the adsorption performance.

[0043] In some embodiments, the inorganic non-metallic material includes, but is not limited to, any one or a combination of at least two of cement, bentonite, or silica.

[0044] The inventors of this application have studied a large number of reinforcing shell materials and found that by using one or more inorganic non-metallic materials among the above-mentioned cement, bentonite or silica as reinforcing shell materials, not only are they widely available, easy to obtain and low in cost; but these materials can also exist in powder form, can be mixed with pore-forming agents, and further attached to the outside of the core particles by spheronization; and these materials are resistant to high temperatures and can maintain high strength after calcination, which is more conducive to their application in the preparation of carbon dioxide adsorbents, thereby improving the mechanical strength and wear resistance of the carbon dioxide adsorbents.

[0045] Optionally, the cement can be selected from high-temperature resistant aluminate cements, such as CA50, CA60, CA70, and CA80, with CA50 being the preferred cement. Due to the high-temperature calcination step during the preparation process, the cement material must be able to withstand high temperatures. The aforementioned cements are all capable of withstanding high temperatures and possess high-temperature resistance, resulting in superior performance.

[0046] It should be noted that the examples of the present invention do not limit the sources and specific models or types of the above-mentioned cement, bentonite and silica, which can be purchased from the market or prepared by methods known in the relevant fields.

[0047] In some embodiments, the average particle size of the core 100 ranges from 0.1 mm to 10 mm. Preferably, the average particle size of the core 100 ranges from 2 nm to 6 nm. For example, the average particle size of the core 100 can be any one of 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm, or a range therebetween.

[0048] By ensuring that the particle size of the core 100 is within the above-mentioned appropriate range, the processing performance of the material can be improved, facilitating manufacturing. It can also effectively control the compaction density of the carbon dioxide adsorbent, thereby effectively controlling the flow rate of carbon dioxide in the adsorbent, ensuring that the adsorbent has sufficient contact with carbon dioxide, allowing the adsorbent to effectively capture carbon dioxide, thereby improving the adsorption efficiency of the adsorbent and enhancing the overall performance of the carbon dioxide adsorbent. If the particle size of the core 100 is too large or too small, the flow rate of carbon dioxide will be affected, resulting in the adsorbent being unable to effectively adsorb carbon dioxide.

[0049] In some embodiments, the thickness of the reinforced outer shell 200 is 0.1 mm to 5 mm. Preferably, the thickness of the reinforced outer shell 200 is 0.5 mm to 1 mm. For example, the thickness of the reinforced outer shell 200 can be any one of 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm, or a range therebetween.

[0050] The appropriate thickness of the reinforced shell 200 can not only ensure that the carbon dioxide has good processing performance, but also ensure that the reinforced shell material has a certain strength and strengthening effect while ensuring a high proportion of effective ingredients in the core 100; it can avoid the reinforced shell 200 being too thick, the reinforced shell material being too much, affecting the gas entering the interior, or the reinforced shell 200 being too thin and not being able to effectively exert the modification effect of the reinforced shell 200.

[0051] In some embodiments, the specific surface area of the carbon dioxide adsorbent is 10 m 2 / g~20m 2 / g; For example, the specific surface area of the carbon dioxide adsorbent can be 10m 2 / g、12m 2 / g、15m 2 / g, 20m 2 Any point value in / g or any range of values between them.

[0052] The carbon dioxide adsorbent of the present application has a high specific surface area, and its specific surface area is 10m 2 / g~20m 2 / g range, thereby improving the adsorption performance of the adsorbent.

[0053] In some embodiments, the pore volume of the carbon dioxide adsorbent is 0.08 cm 3 / g~0.15cm 3 / g. For example, the pore volume of the carbon dioxide adsorbent can be 0.08cm 3 / g, 0.09cm 3 / g, 0.1cm3 / g, 0.12cm 3 / g, 0.14cm 3 / g, 0.15cm 3 Any point value in / g or any range of values between them.

[0054] In some embodiments, the average pore size of the pore structure 210 of the reinforced shell 200 in the carbon dioxide adsorbent is 25 nm to 35 nm. For example, the average pore size of the pore structure 210 can be any one of 25 nm, 26 nm, 28 nm, 30 nm, 32 nm, and 35 nm, or a range of values therebetween.

[0055] In the present embodiment, controlling the specific surface area, pore volume, and average pore diameter of the carbon dioxide adsorbent 210 within the aforementioned ranges facilitates improved adsorption performance. The carbon dioxide adsorbent within this range exhibits a high specific surface area and rich porosity, which facilitates the creation of abundant active sites, thereby enhancing adsorption performance. This avoids the problem of a reduced specific surface area and restricted pore structure, which can reduce the number of active sites and hinder carbon dioxide adsorption.

[0056] It should be noted that this application does not limit the testing methods for the particle size, specific surface area, average pore size of the pore structure 210, and other parameters of the core 100 in the carbon dioxide adsorbent. Conventional methods in the art can be used to measure these parameters. For example, the specific surface area, pore volume, and pore size of the carbon dioxide adsorbent can be calculated using low-temperature nitrogen adsorption-desorption isotherms combined with BET and BJH theory. The core particle size can be tested using a screening method. Since the present invention utilizes a larger core size, screening can be used to determine the larger particle size.

[0057] In a second aspect, in some embodiments, a method for preparing the carbon dioxide adsorbent according to the first aspect is provided, the method comprising: The adsorbent precursor is subjected to a molding process to obtain a core, wherein the core comprises at least one of a metal oxide, an alkaline salt, a molecular sieve or a porous carbon material; The core, the pore-forming agent and the reinforcing shell material are mixed to obtain a mixture; the reinforcing shell material comprises an inorganic non-metallic material; The mixture is subjected to mechanical granulation treatment so that the reinforced shell material covers at least a portion of the surface of the inner core, and then subjected to calcination treatment to obtain a carbon dioxide adsorbent.

[0058] The preparation method of the present invention first prepares the core, then mixes the core, a pore-forming agent, and a reinforcing shell material. After mechanical granulation and calcination, the carbon dioxide adsorbent is obtained. This method is simple to prepare, avoids the use of chemical methods, reduces water and energy use, and reduces costs to a certain extent. The molding method used in the preparation process is mature, highly efficient, and suitable for large-scale production.

[0059] In the preparation method of the present invention, the granulation method of the core is not limited, and the tableting method, spheronization method, extrusion granulation method and the like commonly used in industrial production can be used, which is simple to operate and convenient for large-scale production.

[0060] It should be understood that the “method for preparing a carbon dioxide adsorbent” and the aforementioned “carbon dioxide adsorbent” are based on the same inventive concept, and all the features and advantages described above for the “carbon dioxide adsorbent” are also applicable to the “method for preparing a carbon dioxide adsorbent” and will not be repeated here.

[0061] In some specific embodiments, such as Figure 2 As shown (taking calcium oxide powder as an example), the preparation method of the carbon dioxide adsorbent includes the following steps S100 to S400: Step S100: preparing a core.

[0062] In step S100, the adsorbent precursor is molded using a molding device to obtain a core, that is, to prepare adsorbent core particles.

[0063] Optionally, in step S100 , the adsorbent precursor includes at least one of a calcium precursor, a magnesium precursor, a sodium precursor, a potassium precursor, a molecular sieve precursor, or a porous carbon material precursor.

[0064] Preferably, the adsorbent precursor is selected from a calcium precursor and / or a magnesium precursor. More preferably, the adsorbent precursor is selected from a calcium precursor.

[0065] In some specific embodiments, the calcium precursor includes, but is not limited to, any one or a combination of at least two of calcium acetate, calcium nitrate, calcium hydroxide or calcium carbonate. Preferably, the calcium precursor is selected from one or more of calcium hydroxide, calcium acetate and calcium nitrate.

[0066] Optionally, in step S100, the average particle size of the adsorbent precursor is 50 mesh to 800 mesh; preferably, the average particle size of the adsorbent precursor is 300 mesh to 600 mesh. Exemplarily, the average particle size of the adsorbent precursor can be any one of 50 mesh, 100 mesh, 200 mesh, 300 mesh, 400 mesh, 500 mesh, 600 mesh, and 800 mesh, or a range between any two of the values.

[0067] In this embodiment, the average particle size of the prepared core is in the range of 0.1 mm to 10 mm. Preferably, the average particle size of the core is in the range of 2 nm to 6 nm. For example, the average particle size of the core can be any one of 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm, or a range between any two of them.

[0068] Optionally, in step S100, the molding process includes at least one of a spheronization method, an extrusion molding method, or a tableting method.

[0069] The granulation method of the core of the carbon dioxide adsorbent of the present application is not limited, and the tableting method, spheronization method, extrusion granulation method and the like commonly used in industrial production can be used, which is simple to operate and convenient for large-scale production.

[0070] Step S200: preparing a mixture.

[0071] In step S200, a pore-forming agent and a reinforcing shell material are mixed to obtain a mixture; the reinforcing shell material includes an inorganic non-metallic material.

[0072] Optionally, in step S200 , the pore-forming agent includes, but is not limited to, any one of cellulose, starch, or polyvinyl pyrrolidone (PVP), or a combination of at least two of them.

[0073] By selecting the above-mentioned pore-forming agents, they can be decomposed during the calcination process, thereby forming a pore structure in the reinforced shell, which is convenient for processing and manufacturing, and has a wide source, low cost and is easy to obtain.

[0074] Optionally, in step S200, the inorganic non-metallic material includes at least one of cement, bentonite or silica; Optionally, in step S200, the mass ratio of the pore-forming agent to the reinforcing shell material is 1:5 to 5:1. For example, the mass ratio of the pore-forming agent to the reinforcing shell material can be 1:5, 2:5, 3:5, 4:5, 2:1, 3:1, 5:1, etc.

[0075] By controlling the ratio of pore-forming agent to shell-strengthening material within the above range, the shell of the adsorbent product can be guaranteed to have a rich porous structure while maintaining a certain strength. If the pore-forming agent is present in a high proportion, the shell will be overly porous, resulting in poor strength and even failure to form a reinforced shell after calcination. If the pore-forming agent is present in a low proportion, the shell will have very few pores, poor gas permeability, and significantly reduced adsorption capacity.

[0076] Optionally, in step S200, the mixing method includes at least one of ball milling, mechanical mixing, or air flow milling.

[0077] In the present application, the pore-forming agent and the shell-reinforced material powder can be mixed using conventional mixing methods, such as ball milling, mechanical mixing, or jet milling. This method is easy to control, uniform, and effective, and also helps improve production efficiency.

[0078] Step S300: mechanical granulation treatment.

[0079] In step S300, the core prepared in step S100 is placed in the mixture prepared in step S200 and subjected to mechanical granulation treatment so that the mixture covers at least a portion of the surface of the core.

[0080] Optionally, in step S300, the mechanical granulation treatment may be a spheronization process.

[0081] In this application, the outer shell reinforcement material and pore-forming agent used are both in powder form, making them relatively easy to mix evenly. By using the spheronization method, the outer shell reinforcement material and pore-forming agent powders can be attached to the inner core particles without the use of additional chemical reagents, and without chemically reacting with the adsorbent material. Furthermore, by controlling the spheronization time and speed, the thickness of the outer layer can be controlled.

[0082] Optionally, in step S300 , the mass ratio of the core to the reinforced shell material (or a mixture comprising the reinforced shell and the pore-forming agent) is 10 to 2:1.

[0083] Optionally, in step S300, the mechanical granulation treatment adopts a spheronization method, and the spheronization speed of the spheronization method is 10 rpm to 500 rpm, and the spheronization time is 1 min to 30 min. For example, the spheronization speed is any one of 10 rpm, 50 rpm, 100 rpm, 200 rpm, 300 rpm, 400 rpm, and 500 rpm, or a range between any two of them. The spheronization time can be any one of 1 min, 2 min, 5 min, 10 min, 15 min, 20 min, 25 min, and 30 min, or a range between any two of them.

[0084] Therefore, the present application uses a spheronization process to evenly coat the mixture on the surface of the adsorbent core, and the thickness of the reinforced shell can be precisely controlled by adjusting the spheronization speed and time.

[0085] In this embodiment, the thickness of the reinforced shell is 0.1 mm to 5 mm; preferably, the thickness of the reinforced shell is 0.5 mm to 1 mm.

[0086] Step S400: calcination treatment.

[0087] In step S400, the adsorbent particles obtained in step S300 are calcined at high temperature to remove the pore-forming agent and promote the solidification of the reinforced shell material, while forming a porous structure to obtain a carbon dioxide adsorbent particle material with a porous reinforced shell.

[0088] Optionally, in step S400, the calcination temperature is 650° C. to 950° C., the calcination time is 0.5 h to 2 h, and the calcination atmosphere includes air. For example, the calcination temperature may be any one of 650° C., 700° C., 750° C., 800° C., 850° C., 900° C., and 950° C., or a range between any two thereof; and the calcination time may be any one of 0.5 h, 1 h, 1.5 h, and 2 h, or a range between any two thereof.

[0089] By controlling the calcination temperature within the above range, it is possible to ensure that the formed particles fully react to generate active ingredients with higher purity, thereby ensuring the performance of subsequent products.

[0090] Based on the above configuration, the inventors of this application have creatively proposed a carbon dioxide adsorbent and its preparation method, which ensures good mechanical strength for the adsorbent particles while maintaining their adsorption performance. A reinforced shell material is mixed with a pore-forming agent, and a reinforced shell is formed on the core (inner core) particles via a spheronization method. The thickness of the reinforced shell can be controlled by factors such as the spheronization time and speed. The reinforced shell ensures that the adsorbent particles have high mechanical strength and wear resistance. The pore-forming agent in the reinforced shell forms pores after calcination, which, while functioning as the reinforced shell, ensures that gas can smoothly enter the inner core for adsorption. Furthermore, some adsorbent materials undergo volume changes during the adsorption process, such as the expansion of CaCO3 formed by the adsorption of CaO. The reinforced shell of the present invention effectively prevents particle breakage caused by volume expansion within the adsorbent core, thereby improving structural stability. Furthermore, the reinforced shell effectively reduces the loss of active ingredients in the adsorbent core due to wear, enhancing reusability. The reinforced shell of the present invention has abundant pores, allowing CO2 gas to quickly enter the interior and increase the adsorption rate.

[0091] In a third aspect, in some embodiments, an application of a carbon dioxide adsorbent is provided, the carbon dioxide adsorbent including the aforementioned carbon dioxide adsorbent, and / or, including the carbon dioxide adsorbent prepared by the aforementioned preparation method; the carbon dioxide adsorbent is used in a vehicle.

[0092] The carbon dioxide adsorbent of the present application can be used in vehicles, such as in the field of vehicle exhaust gas treatment. Adsorbing carbon dioxide in vehicle exhaust can not only reduce carbon emissions and protect the ecological environment; it can also reuse the adsorbed carbon dioxide to produce methanol. For example, the vehicle has a carbon bin, and the carbon dioxide adsorbent can be set in the carbon bin, such as placing the carbon dioxide adsorbent in the reaction chamber of the vehicle carbon bin, and the reaction chamber has an air inlet and an air outlet. When the vehicle exhaust enters from the air inlet, it can react with the carbon dioxide adsorbent in the reaction chamber, and the reaction product gas is discharged from the air outlet.

[0093] It should be understood that the carbon dioxide adsorbent can be used in the field of vehicle exhaust gas treatment, but is not limited to this. The carbon dioxide adsorbent can also be used in other scenarios with similar requirements.

[0094] In order to better understand the present invention, the specific implementation process of the present invention will be described in detail below in a specific implementation mode. The embodiments described below are exemplary and are only used to explain this application and are not to be construed as limiting this application. If specific techniques or conditions are not specified in the embodiments, they shall be carried out in accordance with the techniques or conditions described in the literature in this field or in accordance with the product specifications.

[0095] Example 1 The preparation of the carbon dioxide adsorbent comprises the following steps: 1000g of calcium hydroxide powder (purity 95%, particle size 600 mesh) was added with water (50wt%) and kneaded, and then formed using a hydraulic extruder to obtain adsorbent core particles with a diameter of 5mm, that is, the inner core.

[0096] The formed particles, also known as the core, were placed in an oven and dried at 105°C for 24 hours. CA50 high-alumina cement was selected as the reinforcing shell material, and cellulose was selected as the pore-forming agent. The two were mixed in a ratio of 1:1 to form the shell powder.

[0097] The core particles (inner core) are mixed with the shell powder and spheronized (at a speed of 10 rpm for 10 minutes) to produce carbon dioxide adsorbent particles with a reinforced shell thickness of 0.1 mm. These particles are then calcined in a muffle furnace at 800°C for 2 hours in an air atmosphere to decompose the calcium hydroxide into calcium oxide and the pore-forming agent into pores, resulting in the final carbon dioxide adsorbent.

[0098] Example 2 The preparation of the carbon dioxide adsorbent comprises the following steps: 1000g of calcium hydroxide powder (purity 95%, particle size 600 mesh) was added with water (50wt%) and kneaded, and then formed using a hydraulic extruder to obtain adsorbent core particles with a diameter of 5mm, that is, the inner core.

[0099] The formed particles, also known as the core, were placed in an oven and dried at 105°C for 24 hours. CA50 high-alumina cement was selected as the reinforcing shell material, and cellulose was selected as the pore-forming agent. The two were mixed in a ratio of 1:1 to form the shell powder.

[0100] The core particles (inner core) are mixed with the shell powder and spheronized (at a speed of 100 rpm for 30 minutes) to produce carbon dioxide adsorbent particles with a reinforced shell thickness of 0.5 mm. These particles are then calcined in a muffle furnace at 800°C for 2 hours in an air atmosphere to decompose the calcium hydroxide into calcium oxide and the pore-forming agent into pores, resulting in the final carbon dioxide adsorbent.

[0101] Example 3 The preparation of the carbon dioxide adsorbent comprises the following steps: 1000g of calcium hydroxide powder (purity 95%, particle size 600 mesh) was added with water (50wt%) and kneaded, and then formed using a hydraulic extruder to obtain adsorbent core particles with a diameter of 5mm, that is, the inner core.

[0102] The formed particles, also known as the core, were placed in an oven and dried at 105°C for 24 hours. CA50 high-alumina cement was selected as the reinforcing shell material, and cellulose was selected as the pore-forming agent. The two were mixed in a ratio of 1:1 to form the shell powder.

[0103] The core particles (inner core) are mixed with the shell powder and spheronized (at 200 rpm for 60 minutes) to produce carbon dioxide adsorbent particles with a reinforced shell thickness of 1 mm. These particles are then calcined in a muffle furnace at 800°C for 2 hours in an air atmosphere to decompose the calcium hydroxide into calcium oxide and the pore-forming agent into pores, resulting in the final carbon dioxide adsorbent.

[0104] Example 4 The difference between Example 4 and Example 2 is that: CA50 high-alumina cement was selected as the reinforced shell material, and starch was selected as the pore-forming agent, and the two were mixed in a ratio of 7:3.

[0105] The rest are the same as in Example 2.

[0106] Example 5 The difference between Example 5 and Example 2 is that: CA50 high-alumina cement was selected as the reinforced shell material, and polyvinyl pyrrolidone (PVP) was selected as the pore-forming agent, and the two were mixed in a ratio of 1:1.

[0107] The rest are the same as in Example 2.

[0108] Example 6 The difference between Example 6 and Example 2 is that: Bentonite is selected as the reinforcing shell material, and cellulose is selected as the pore-forming agent, and the two are mixed in a ratio of 1:1.

[0109] The rest are the same as in Example 2.

[0110] Example 7 The difference between Example 7 and Example 2 is that: Silica is selected as the reinforcing shell material and cellulose is selected as the pore-forming agent, and the two are mixed in a ratio of 1:1.

[0111] The rest are the same as in Example 2.

[0112] Example 8 The difference between Example 8 and Example 2 is that: 1000 g of calcium acetate powder (purity 95%, particle size 500 mesh) was added with water (50 wt%) and kneaded, and then formed using a hydraulic extruder to obtain adsorbent core particles with a diameter of 3 mm, that is, the inner core.

[0113] The rest are the same as in Example 2.

[0114] Example 9 The difference between Example 9 and Example 2 is that: 1000 g of calcium nitrate powder (purity 95%, particle size 800 mesh) was added with water (50 wt%) and kneaded, and then formed using a hydraulic extruder to obtain adsorbent core particles with a diameter of 8 mm, that is, the inner core.

[0115] The rest are the same as in Example 2.

[0116] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that: In the preparation of the carbon dioxide adsorbent in this comparative example, the reinforcing shell material was omitted.

[0117] The rest are the same as in Example 2.

[0118] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that: In the preparation of the carbon dioxide adsorbent in this comparative example, the pore-forming agent was omitted. That is, the reinforced shell of comparative example 2 has no pore structure.

[0119] The rest are the same as in Example 2.

[0120] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that: In the preparation of the carbon dioxide adsorbent in this comparative example, the reinforcing shell material and the pore-forming agent were omitted. That is, comparative example 3 did not have a reinforcing shell.

[0121] The rest are the same as in Example 2.

[0122] Performance Testing The carbon dioxide adsorbents obtained in the above examples and comparative examples were subjected to performance tests, including: (1) Average strength test: Use a particle strength meter to complete the particle strength test.

[0123] (2) Adsorption capacity test: The prepared particle sample was ground into powder using a mortar and pestle, and the adsorption capacity test of the adsorbent was completed using TGA. The experimental gas was 15 vol.% CO2, N2 was the balance gas, the reaction temperature was 25°C to 800°C, and the heating rate was 10°C / min. The maximum weight gain ratio of the sample was recorded to calculate the adsorption capacity.

[0124] The test results are shown in Table 1 below.

[0125] Table 1 Preparation parameters and test results of carbon dioxide adsorbents in various examples and comparative examples As can be seen from Table 1, compared to Comparative Examples 1-3, the carbon dioxide produced in Examples 1-9 of the present invention achieves both higher strength and higher adsorption capacity. This indicates that the carbon dioxide adsorbents produced in Examples 1-9 of the present invention meet the design standards. Within the scope defined by the present invention, by adjusting the ratio of the components or controlling the thickness of the reinforced shell by setting different spheronization speeds and times, the strength and adsorption capacity of the produced carbon dioxide adsorbent particles meet the design requirements.

[0126] However, the sample of Comparative Example 1 did not use a reinforcing shell material, and no reinforcing shell was formed. The pore-forming agent could not function only by spheronization and attachment. The particle strength was low, and the adsorption amount was not significantly different from that without adding a pore-forming agent, indicating that the reinforcing material and the pore-forming agent can only play a significant role when used in combination. Comparative Example 2 did not add a pore-forming agent. Although a reinforcing shell was formed, the shell structure was tight and there was no rich pore structure because no pore-forming agent was added. Therefore, it was difficult for carbon dioxide gas to enter the interior of the adsorbent. Although the particles have high strength, the adsorption capacity is very low. Comparative Example 3 is not doped with other additives and does not form a reinforcing shell. Although the adsorption capacity is high, the particle strength is too low and does not meet the use requirements. Therefore, the adsorbents of Comparative Examples 1 to 3 either do not meet the use requirements in terms of strength or do not meet the use requirements in terms of adsorption capacity. It is difficult to ensure the adsorption capacity while improving the strength.

[0127] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0128] The basic principles of the present invention have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in the present invention are merely illustrative and non-limiting, and should not be construed as necessarily possessed by each embodiment of the present invention. Furthermore, the specific details disclosed above are provided for illustrative purposes and to facilitate understanding, and are not intended to be limiting. These details do not necessarily limit the present invention to being implemented using these specific details.

[0129] It should be noted that the terms "and / or" or " / " used herein are merely a description of an association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist at the same time, and B exists alone. The singular forms "a," "the," and "the" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0130] In the detailed description and claims, a list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may include a single element or multiple elements. Item B may include a single element or multiple elements. Item C may include a single element or multiple elements.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A carbon dioxide adsorbent, characterized in that The carbon dioxide adsorbent comprises a core and a reinforced shell covering at least a portion of the surface of the core; The core comprises at least one of a metal oxide, an alkaline salt, a molecular sieve or a porous carbon material; The reinforced shell has a pore structure, and the reinforced shell material includes an inorganic non-metallic material.

2. The carbon dioxide adsorbent according to claim 1, characterized in that The inorganic non-metallic material includes at least one of cement, bentonite or silica; And / or, the inner core comprises at least one of a calcium-based adsorbent, a magnesium-based adsorbent, a sodium-based adsorbent, a potassium-based adsorbent, a molecular sieve or a porous carbon material.

3. The carbon dioxide adsorbent according to claim 1, characterized in that The average particle size of the core is in the range of 0.1 mm to 10 mm; And / or, the thickness of the reinforced shell is 0.1 mm to 5 mm.

4. The carbon dioxide adsorbent according to any one of claims 1 to 3, characterized in that The specific surface area of the carbon dioxide adsorbent is 10m 2 / g~20m 2 / g; And / or, the pore volume of the carbon dioxide adsorbent is 0.08 cm 3 / g~0.15cm 3 / g; And / or, the average pore diameter of the pore structure of the reinforced shell in the carbon dioxide adsorbent is 25 nm to 35 nm.

5. A method for preparing a carbon dioxide adsorbent, characterized in that: The method comprises: forming an adsorbent precursor to obtain a core, wherein the core comprises at least one of a metal oxide, an alkaline salt, a molecular sieve, or a porous carbon material; The core, the pore-forming agent and the reinforcing shell material are mixed to obtain a mixture; the reinforcing shell material comprises an inorganic non-metallic material; The mixture is subjected to mechanical granulation treatment so that the reinforced shell material covers at least a portion of the surface of the core, and then subjected to calcination treatment to obtain the carbon dioxide adsorbent.

6. The method for preparing a carbon dioxide adsorbent according to claim 5, wherein: The step of obtaining the kernel satisfies at least one of the following characteristics: (1) The adsorbent precursor includes at least one of a calcium precursor, a magnesium precursor, a sodium precursor, a potassium precursor, a molecular sieve precursor, or a porous carbon material precursor; (2) The average particle size of the adsorbent precursor is 50 mesh to 800 mesh; (3) The average particle size of the core is in the range of 0.1 mm to 10 mm; (4) The molding process includes at least one of spheronization, extrusion molding or tableting.

7. The method for preparing a carbon dioxide adsorbent according to claim 6, wherein: The calcium precursor includes at least one of calcium hydroxide, calcium acetate, calcium nitrate or calcium carbonate.

8. The method for preparing a carbon dioxide adsorbent according to claim 5, wherein: The step of obtaining the mixture satisfies at least one of the following characteristics: (1) The pore-forming agent comprises at least one of cellulose, starch or polyvinyl pyrrolidone; (2) The inorganic non-metallic material includes at least one of cement, bentonite or silica; (3) The mass ratio of the pore-forming agent to the reinforcing shell material is 1:5 to 5:1; (4) The mass ratio of the core and the reinforced shell material is 10 to 2:1; (5) The mixing method includes at least one of ball milling, mechanical mixing or air milling.

9. The method for preparing a carbon dioxide adsorbent according to claim 5, wherein: The mechanical granulation treatment includes a spheronization method, wherein the spheronization speed of the spheronization method is 10 rpm to 500 rpm, and the spheronization time is 1 min to 30 min; And / or, the calcination temperature is 650° C. to 950° C., the calcination time is 0.5 h to 2 h, and the calcination atmosphere includes air.

10. An application of a carbon dioxide adsorbent, characterized in that: The carbon dioxide adsorbent includes the carbon dioxide adsorbent according to any one of claims 1 to 4, and / or includes the carbon dioxide adsorbent prepared by the preparation method according to any one of claims 5 to 9; The carbon dioxide absorbent is used in a vehicle.

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