Carbon dioxide adsorbent as well as preparation method and application thereof

Abstract

The invention discloses a carbon dioxide adsorbent and a preparation method and application thereof, the adsorbent comprises a carrier and an active component, the carrier is one or more of alumina microspheres, silicon-aluminum balls and silicon dioxide balls, and the active component is one or more of carbonates formed by IA family elements. The preparation method of the carbon dioxide adsorbent comprises the following steps: (1) uniformly mixing alumina microspheres, alkali and water, and treating to obtain first slurry; (2) drying and roasting the first slurry, and then uniformly mixing the first slurry with acid and water to obtain second slurry; and (3) drying and roasting the second slurry, then uniformly mixing the second slurry with a first binder, a second binder, an active component and water to obtain third slurry, and drying and roasting the third slurry to obtain the carbon dioxide adsorbent. The mode of combining in-situ generation of the active component and loading and introduction of the active component is adopted, so that the loading capacity of the active component is improved, and the distribution uniformity of the active component of the adsorbent is also ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide capture, and relates to a solid carbon dioxide adsorption material and a preparation method thereof, in particular to a supported carbon dioxide solid adsorbent and a preparation method thereof. Background Art

[0002] At present, the mainstream post-combustion carbon capture technologies include solvent absorption method and solid adsorbent adsorption method. The solvent absorption technology is to carry out chemical adsorption at the CO 2 source. The CO 2 absorption technology based on amine solution and alkali solution has been widely used in the chemical industry, especially in coal-fired power plants. However, there are still some insurmountable disadvantages in the application process, including large equipment size, large solvent consumption, etc. At the same time, amine solvents have corrosiveness and are easy to degrade. Compared with the traditional solvent absorption process, the adsorption process using solid adsorbents has the advantages of easy treatment, no solvent loss, low energy consumption, small environmental pollution, simple process, and low operating cost.

[0003] The carbon dioxide hydration adsorption is mainly prepared by matching different carriers with alkali metal carbonates as the carbon dioxide adsorption active components by methods such as direct impregnation or stepwise impregnation. Taking potassium carbonate as the active center as an example, the adsorption process mainly includes three reaction processes: the hydration reaction of potassium carbonate, the decarbonization process (carbonation reaction), and the regeneration reaction (decomposition reaction of potassium bicarbonate). The specific reaction equations are as follows:

[0004] Adsorbent hydration process (hydration reaction): K 2 CO 3 +1.5H 2 O = K 2 CO 3 ·1.5H 2 O;

[0005] Adsorbent decarbonization process (carbonation reaction): K 2 CO 3 ·1.5H 2 O + CO 2 = 2KHCO 3 +0.5H 2 O;

[0006] Adsorbent regeneration reaction (decomposition reaction of potassium bicarbonate): 2KHCO 3 = K 2 CO 3 + CO 2 + H 2 O;

[0007] It is found that the alumina support in CO 2 and H 2In an O coexistence atmosphere, in addition to the formation of KHCO 3 , a by-product KAl(CO 3 ) 2 (OH) 2 will appear. During the regeneration reaction process, the decomposition temperature of KHCO 3 is 130 °C, while the decomposition temperature of the by-product is between 260 - 350 °C. The energy consumption of the CO 2 hydration adsorption process is mainly concentrated in the regeneration reaction of the adsorbent, and the regeneration degree of the adsorbent directly affects the repeated stability of the hydration and decarbonization processes of the adsorbent. This by-product seriously affects the adsorption capacity and regeneration temperature of the adsorbent for cyclic adsorption of CO 2 , thereby reducing the economy and applicability of this technology.

[0008] Patent CN101269316A provides a highly active potassium-based solid absorbent for removing CO 2 from flue gas and its preparation method. This solid absorbent uses hexagonal potassium carbonate as the active component, and uses coal-based activated carbon, or wood-based activated carbon, or coarse pore silica gel as the carrier, and is made by the excess impregnation method. The raw materials required for this absorbent are cheap and easily available chemical drugs and carrier materials; the production process of the absorbent is simple and the cost is low; its carbonation temperature is 60 - 80 °C, and the regeneration temperature is 100 - 200 °C, belonging to a low-temperature absorbent. At this temperature, the absorbent is not easily deactivated and can maintain a high conversion rate after multiple cycles. The coal-based activated carbon, wood-based activated carbon, and coarse pore silica gel carriers used in this patent cannot meet the mechanical strength requirements of the adsorbent for fluidized beds and cannot meet the stability of the adsorbent for industrial applications.

[0009] Patent CN114632406A discloses a preparation method and device for a supported carbon dioxide solid adsorbent, including: using high-temperature air as the fluidization medium to circulate and fluidize porous carrier particles in a fluidized bed; the active component solution is atomized and sprayed into the fluidized bed from the bottom of the bed, and the atomized droplets penetrate into the pores of the porous carrier particles; the high-temperature air also serves as the drying medium to evaporate the active component droplets immersed in the pores of the porous carrier, and the active component is loaded on the pore walls of the porous carrier particles; the loaded particles are calcined. It also relates to a preparation device, including a fluidized bed body, a diversion pipe is provided inside the fluidized bed body, the diversion pipe is coaxially arranged with the central axis of the fluidized bed body and is close to the air distribution plate at the bottom of the fluidized bed body, and the diversion pipe is used to divert the fluidization direction of the porous carrier particles. The purpose of the present invention is to make the reaction between carbon dioxide and the active component more sufficient during the diffusion process in the pores, thereby increasing the adsorption capacity and reducing the energy consumption. This method uses γ-aluminum oxide as the porous carrier and is prone to react with water and CO 2 to form a by-product KAl(CO 3 ) 2 (OH)2 , which leads to an increase in the regeneration temperature and a decrease in the regeneration stability of the adsorbent, thereby reducing the applicability of this technology. Summary of the Invention

[0010] For the carbon dioxide adsorption process, increasing the loading amount of the active component on the adsorbent promotes the adsorption. However, the case of a higher loading amount is closely related to the introduction method of the active component. For some carriers, limited by the mismatch between the water absorption rate of the carrier and the solubility of the active component, it is difficult to obtain a high loading amount by using a one-step loading method; if a step-by-step loading method is used, it will go through multiple heat treatment processes such as drying and calcination, resulting in the aggregation of the active component, thereby reducing the activity of the adsorbent.

[0011] Therefore, in view of the technical problem of the contradiction between a high content of the active component and a uniform distribution, the present invention provides a carbon dioxide adsorbent and a preparation method thereof. By combining the in-situ generation of the active component and the introduction of the active component by loading, not only the loading amount of the active component is increased, but also the uniformity of the distribution of the active component in the adsorbent is ensured.

[0012] In the first aspect of the present invention, a carbon dioxide adsorbent is provided. The adsorbent includes a carrier and an active component. Among them, the carrier is one or more of alumina microspheres, silica-alumina spheres, and silica spheres, preferably alumina microspheres; the active component is one or more of carbonates formed by elements of Group IA, specifically, it can be selected from one or more of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, lithium carbonate, and lithium bicarbonate, preferably one or more of potassium carbonate and sodium carbonate.

[0013] Further, the particle size distribution D50 of the carbon dioxide adsorbent is 100 - 300 μm, preferably 150 - 160 μm; the specific surface area is 10 - 500 m 2 / g, preferably 50 - 300 m 2 / g, more preferably 100 - 200 m 2 / g.

[0014] Further, the proportion of the mesopore volume in the total pore volume of the carbon dioxide adsorbent is 30 - 90%, where the mesopores are pores with a pore diameter greater than 2 nm and less than 100 nm.

[0015] Further, based on weight, the content of the active component in the carbon dioxide adsorbent is 1 - 50%, preferably 5 - 35%.

[0016] Further, the attrition index of the carbon dioxide adsorbent is 0.1 - 10%, preferably 0.5 - 5%.

[0017] Further, the size of the alumina microspheres is 5 - 500 μm, preferably 10 - 300 μm.

[0018] In the second aspect of the present invention, a method for preparing a carbon dioxide adsorbent is provided, comprising the following steps:

[0019] (1) Mix alumina microspheres, an alkali, and water evenly to obtain a first slurry;

[0020] (2) Dry and calcine the first slurry obtained in step (1), and then mix it evenly with an acid and water to obtain a second slurry;

[0021] (3) Dry and calcine the second slurry obtained in step (2), and then mix it evenly with a first binder, a second binder, an active component, and water to obtain a third slurry;

[0022] (4) The third slurry obtained in step (3) is dried and calcined to obtain a carbon dioxide adsorbent.

[0023] Further, in the above method for preparing a carbon dioxide adsorbent, the alkali in step (1) is an alkali metal compound, and the alkali metal is selected from at least one of lithium, sodium, and potassium. Specifically, the alkali can be selected from one or more of potassium hydroxide, sodium hydroxide, potassium carbonate, and sodium carbonate, and preferably sodium carbonate.

[0024] Further, in the above method for preparing a carbon dioxide adsorbent, the mixing in step (1) can be carried out by impregnation, specifically, it can be equal - volume impregnation or multiple - excess impregnation.

[0025] Further, in the above method for preparing a carbon dioxide adsorbent, the size of the alumina microspheres in step (1) is 5 - 500 μm, preferably 10 - 500 μm, more preferably 20 - 50 μm, wherein the particle size distribution D50 is 50 - 200 μm, preferably 30 - 80 μm; the specific surface area of the alumina microspheres is 5 - 500 m 2 / g, preferably 10 - 300 m 2 / g, more preferably 50 - 200 m 2 / g.

[0026] Further, in the above method for preparing a carbon dioxide adsorbent, the amounts of the alumina microspheres, the alkali, and water in step (1) are (1 - 50):(0.1 - 20):100, preferably (5 - 30):(0.1 - 5):100.

[0027] Further, in the above method for preparing a carbon dioxide adsorbent, the treatment temperature in step (1) is 30 - 100 °C, preferably 50 - 90 °C; the treatment time is 10 - 200 min, preferably 30 - 60 min.

[0028] Further, in the preparation method of the above carbon dioxide adsorbent, the calcination in step (2) is usually carried out under the following conditions: the calcination temperature is 500 - 1200 °C, preferably 600 - 800 °C; the calcination time is 0.5 - 48 h, preferably 1 - 12 h. The calcination is generally carried out in the presence of an inert atmosphere.

[0029] Further, in the preparation method of the above carbon dioxide adsorbent, the drying in step (2) is generally carried out under the following drying conditions: the drying temperature is 50 - 300 °C, preferably 80 - 180 °C, and the drying time is 0.5 - 72 h, preferably 1 - 24 h.

[0030] Further, in the preparation method of the above carbon dioxide adsorbent, the acid in step (2) is one or more of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, carbonic acid, and acetic acid, preferably one or more of hydrochloric acid, phosphoric acid, nitric acid, and acetic acid.

[0031] Further, in the preparation method of the above carbon dioxide adsorbent, the dosage ratio of the acid and water in step (2) is (0.1 - 20):100, preferably (0.1 - 5):100.

[0032] Further, in the preparation method of the above carbon dioxide adsorbent, the calcination in step (3) is carried out under the following operating conditions: the calcination temperature is 300 - 1000 °C, preferably 400 - 500 °C; the calcination time is 0.5 - 48 h, preferably 1 - 12 h.

[0033] Further, in the preparation method of the above carbon dioxide adsorbent, the first binder in step (3) is selected from one or more of silica sol, alumina sol, kaolin, sepiolite, diatomite, rectorite, montmorillonite, and bentonite, preferably one or more of silica sol, kaolin, rectorite, and bentonite.

[0034] Further, in the preparation method of the above carbon dioxide adsorbent, the active components in step (3) are one or more of the basic carbonates of the elements in the first main group of the periodic table and the basic acetates of the elements in the first main group, and specifically can be selected from one or more of potassium carbonate, potassium bicarbonate, potassium acetate, sodium carbonate, sodium bicarbonate, sodium acetate, lithium carbonate, lithium bicarbonate, and lithium acetate, preferably one or more of potassium carbonate, potassium bicarbonate, sodium carbonate, and sodium bicarbonate.

[0035] Further, in the preparation method of the above carbon dioxide adsorbent, the preparation method of the second binder in step (3) includes the following steps:

[0036] (3.1) Mix an aluminum-containing compound, clay, and an alkali solution evenly for treatment to obtain a material stream A;

[0037] (3.2) Mix the compound containing a Group IA metal element, an acid solution, and a surfactant uniformly for treatment to obtain stream B;

[0038] (3.3) Mix stream A and stream B uniformly and carry out a reaction to obtain a second binder.

[0039] Preferably, as some specific embodiments, in the preparation method of the above-mentioned second binder, the aluminum-containing compound in step (3.1) is selected from one or more of alumina, aluminum hydroxide, and pseudo-boehmite, preferably alumina. Further, the specific surface area of the alumina is 100 - 300 m 2 / g, and the total pore volume is 0.2 - 0.5 ml / g.

[0040] Preferably, as some specific embodiments, in the preparation method of the above-mentioned second binder, the clay in step (3.1) is selected from one or more of bentonite, attapulgite, and kaolin.

[0041] Preferably, as some specific embodiments, in the preparation method of the above-mentioned second binder, the alkali solution in step (3.1) is an inorganic alkali solution, specifically selected from one or more of sodium hydroxide and potassium hydroxide. The molar concentration of the alkali solution is generally controlled to be 0.01 - 1 mol / L, preferably controlled to be 0.5 - 0.8 mol / L.

[0042] Preferably, as some specific embodiments, in the preparation method of the above-mentioned second binder, the mass ratio of the aluminum-containing compound, clay, and alkali solution in step (3.1) is 1:(0.01 - 10):(0.1 - 20), preferably 1:(0.1 - 1):(1 - 5).

[0043] Preferably, as some specific embodiments, in the preparation method of the above-mentioned second binder, the treatment conditions in step (3.1) are as follows: the treatment temperature is 30 - 100 °C, preferably 40 - 50 °C; the treatment time can be controlled to be 10 - 200 min, preferably 30 - 60 min. The mixing can be carried out by any of the existing methods in the art that can achieve uniform mixing of materials, such as stirring.

[0044] Preferably, as some specific embodiments, in the preparation method of the above-mentioned second binder, the compound containing a Group IA metal element in step (3.2) is one or more of basic carbonates and basic acetates formed by Group IA elements of the periodic table, specifically selected from one or more of potassium carbonate, potassium bicarbonate, potassium acetate, sodium carbonate, sodium bicarbonate, sodium acetate, lithium carbonate, lithium bicarbonate, and lithium acetate, preferably one or more of potassium carbonate, potassium bicarbonate, sodium carbonate, and sodium bicarbonate.

[0045] Preferably, as some specific embodiments, in the preparation method of the above-mentioned second binder, in step (3.2), the mass ratio of the compound containing a Group IA metal element of the periodic table, the acid solution and the surfactant is (0.1-20):(20-100):1, preferably (1-10):(40-80):1.

[0046] Preferably, as some specific embodiments, in the preparation method of the above-mentioned second binder, in step (3.2), the surfactant is one or more of anionic and non-ionic surfactants. The anionic surfactant is one or more of carboxylates, sulfonates, sulfates, and phosphates, selected from one or more of sodium stearate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, potassium hexadecyl phosphate, and sodium lauroyl sarcosinate; the non-ionic surfactant is one or more of polyoxyethylene derivatives, alkyl alcohol amides, polyol monofatty acid esters, alkylamine oxides, and N-alkyl pyrrolidones, selected from one or more of fatty alcohol polyoxyethylene ethers, coconut fatty acid diethylamide, glycerol fatty acid ester, dodecyldimethylamine oxide, and lauryl pyrrolidone.

[0047] Preferably, as some specific embodiments, in the preparation method of the above-mentioned second binder, in step (3.2), the acid solution is an inorganic acid solution and / or an organic acid solution, specifically selected from one or more of nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, and formic acid solution, preferably one or more of nitric acid, hydrochloric acid, and phosphoric acid, more preferably nitric acid; the molar concentration of the acid solution is 0.01-2 mol / L, preferably 0.1-0.5 mol / L.

[0048] Preferably, as some specific embodiments, in the preparation method of the above-mentioned second binder, the treatment conditions in step (3.2) are as follows: the treatment temperature is 30-100 °C, preferably 40-50 °C; the treatment time is 10-200 min, preferably 30-60 min. The mixing can be carried out by any of the existing methods in the art that can achieve uniform mixing of materials, such as stirring.

[0049] Preferably, as some specific embodiments, in the preparation method of the above-mentioned second binder, the treatment conditions in step (3.3) are as follows: the treatment temperature is 30-100 °C, preferably 50-90 °C; the treatment time is 10-200 min, preferably 30-60 min. The mixing can be carried out by any of the existing methods in the art that can achieve uniform mixing of materials, such as stirring.

[0050] Furthermore, in the preparation method of the above-mentioned carbon dioxide adsorbent, the temperature of the mixing treatment in step (3) is 30-100 °C, preferably 40-60 °C.

[0051] Further, in the preparation method of the above carbon dioxide adsorbent, before drying the third slurry in step (4), passivation treatment is preferably carried out first. The passivation treatment is to treat the third slurry at 10 - 100 °C, preferably 30 - 50 °C for a period of time. Generally, the treatment time is 5 - 60 min, preferably 10 - 30 min.

[0052] Further, in the preparation method of the above carbon dioxide adsorbent, shaping treatment is also carried out in step (4). The shaping treatment can be carried out before drying or after calcination; shaping can adopt any one of the existing shaping methods in the art, such as spray drying shaping, extrusion molding, or rolling ball molding, and specifically can be one or more of spherical, strip-shaped, clover-shaped, or four-leaf clover-shaped.

[0053] Further, in the preparation method of the above carbon dioxide adsorbent, the drying temperature in step (4) is 100 - 300 °C, preferably 120 - 150 °C; the calcination temperature is 300 - 600 °C, preferably 350 - 400 °C; the calcination is generally carried out under an inert atmosphere condition.

[0054] The present invention also provides an application of the above carbon dioxide adsorbent in the carbon dioxide adsorption process. The application conditions are as follows: the reaction pressure is normal pressure to 2 Mpa, preferably 0.3 - 1 Mpa, the hydration temperature is 20 - 300 °C, preferably 40 - 100 °C, the adsorption temperature is 20 - 200 °C, preferably 30 - 90 °C, the regeneration temperature is 100 - 400 °C, preferably 120 - 300 °C, and the volume fraction of CO in the raw material gas is 1 - 50%, preferably 5 - 30%, and the adsorption gas space velocity is 50 - 2000 h 2 -1, preferably 100 - 500 h -1 -1. -1 .

[0055] The carbon dioxide adsorbent and its preparation method provided by the present invention have one or several combinations of the following advantages, specifically as follows:

[0056] (1) The active component loading content of the carbon dioxide adsorbent provided by the present invention is high, and it does not require multiple impregnations, greatly reducing the process difficulty. Moreover, the active component has a strong interaction with the carrier and is not easily lost, and the adsorption performance is stable, solving the problems of high active component content and uneven distribution (easy to aggregate) of the existing adsorbent.

[0057] (2) In the method for preparing the carbon dioxide adsorbent provided by the present invention, the alumina microspheres first come into contact with an alkaline solution and are treated to form meta-aluminates. After acid treatment, aluminum hydroxide and corresponding salts are formed. During the third slurry mixing process, the aluminum hydroxide dissolves under alkaline conditions, forming mesopores and macropores. At the same time, the salts in-situ generated can serve as the active centers of the carbon dioxide adsorbent. On the one hand, it increases the content of the active components of the adsorbent, and on the other hand, this part of the in-situ generated active centers is stable and not easily lost, improving the adsorption performance of the adsorbent.

[0058] (3) In the method for preparing the carbon dioxide adsorbent provided by the present invention, the combined use of the first binder and the second binder will form a certain amount of mesoporous structure during the spray drying and heating process, thereby controlling the proportion of mesopores in the total pore volume of the adsorbent, which is beneficial to improving the mass transfer efficiency of the gas in the adsorbent. In addition, the adsorbent has high strength and small abrasion loss. The second binder contains rich microporous structures, which will promote the finally prepared adsorbent to have a high carbon dioxide adsorption capacity.

[0059] (4) In the method for preparing the carbon dioxide adsorbent provided by the present invention, during the preparation process of the second binder, the clay is first treated with an alkaline solution. The surface structure of the clay is prone to precipitate silicon dioxide under alkaline conditions, thus forming more micropores. On the one hand, it shows advantages in adsorbing carbon dioxide, and on the other hand, under the action of the surfactant, the compounds containing metal elements in Group IA of the periodic table are more likely to enter the micropore channels to form a relatively stable structure. In addition, after the alumina is treated with an alkaline solution, the adsorbent prepared after the clay and the alumina are spray-formed in the adsorbent will not generate by-products KAl(CO 3 ) 2 (OH) 2 under the coexistence conditions of water and carbon dioxide, so that the adsorbent has a high carbon dioxide adsorption capacity and cycle stability. Detailed Embodiments

[0060] The technical solutions and technical effects of the present invention will be further described below in conjunction with the detailed embodiments.

[0061] Unless otherwise clearly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "having" etc. will be understood to include the stated elements or components, without excluding other elements or other components.

[0063] In this article, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit a specific position or relative relationship. In other words, in some embodiments, the terms "first", "second", etc. can also be interchanged with each other.

[0064] In this text, all numerical values of parameters (e.g., quantities or conditions) should be understood to be modified in all cases by the term "about", whether or not "about" actually appears before the numerical value.

[0065] Unless otherwise specified, the experimental methods in the following examples are all conventional methods in the art. Unless otherwise specified, the experimental materials used in the following examples are all purchased from regular biochemical reagent stores.

[0066] The analysis method of the present invention: The specific surface area and pore volume are measured by the low-temperature liquid nitrogen physical adsorption method.

[0067] In this text, the attrition index of the carbon dioxide adsorbent is measured by an attrition index analyzer according to "Q / TSH 3490 909-2006 Determination of the Attrition Index of Fluid Catalytic Cracking Catalysts - Straight Tube Method".

[0068] Example 1

[0069] Mix alumina microspheres (particle size distribution D50 is 68 μm, specific surface area is 193 m 2 / g), sodium hydroxide solution (0.1 mol / L), and water evenly in a mass ratio of 6:4:100, and stir at 80 °C for 40 min to form a first slurry.

[0070] Dry the first slurry at 120 °C for 12 h and calcine it at 700 °C for 4 h to obtain a material. Mix hydrochloric acid solution (0.02 mol / L) and water evenly in a mass ratio of 2:100, and stir with the material obtained after calcination at 55 °C for 60 min to form a second slurry.

[0071] Mix pseudoboehmite, bentonite, and sodium hydroxide solution (0.6 mol / L) evenly in a mass ratio of 1:0.2:4.5, and stir at 45 °C for 50 min to obtain stream A; mix potassium carbonate, nitric acid (0.2 mol / L), and sodium stearate evenly in a mass ratio of 3:70:1, and stir at 50 °C for 35 min to obtain stream B; mix stream A and stream B evenly and stir at 80 °C for 60 min to obtain a second binder.

[0072] Dry the second slurry at 120 °C for 12 h and calcine it at 450 °C for 6 h to obtain a material, mix it evenly with silica sol, the second binder, potassium bicarbonate, and water to form a third slurry. Passivate it at 40 °C for 20 min; then spray-form it, dry it at 120 °C for 12 h, and calcine it at 400 °C for 6 h to obtain a carbon dioxide adsorbent.

[0073] The specific surface area of the adsorbent is 190 m 2 / g, the mesopores account for 47.2% of the total pores, the active component loading is 32.4%, and the attrition index is 3.2%. The CO adsorption capacity of the fresh adsorbent is 2.14 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 2.03 mmol / g. For the gas after adsorption, the CO removal rate is 94.5%. 2 The CO adsorption capacity of the fresh adsorbent is 2.14 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 2.03 mmol / g. For the gas after adsorption, the CO removal rate is 94.5%. 2 The CO adsorption capacity of the fresh adsorbent is 2.14 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 2.03 mmol / g. For the gas after adsorption, the CO removal rate is 94.5%. 2 The CO adsorption capacity of the fresh adsorbent is 2.14 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 2.03 mmol / g. For the gas after adsorption, the CO removal rate is 94.5%.

[0074] Example 2

[0075] Mix alumina microspheres (particle size distribution D50 is 68 μm, specific surface area is 193 m 2 / g), sodium carbonate solution (0.1 mol / L), and water evenly in a mass ratio of 15:2.5:100, and stir at 80 °C for 40 min to form the first slurry.

[0076] Dry the first slurry at 120 °C for 12 h and calcine it at 650 °C for 6 h to obtain the material. Mix phosphoric acid solution (0.02 mol / L) and water evenly in a mass ratio of 4:100, and stir with the material obtained after calcination at 55 °C for 60 min to form the second slurry.

[0077] Mix aluminum hydroxide, attapulgite, and potassium hydroxide solution (0.6 mol / L) evenly in a mass ratio of 1:0.9:1.5, and stir at 45 °C for 50 min to obtain stream A; mix potassium bicarbonate, phosphoric acid (0.1 mol / L), and sodium lauroyl sarcosinate evenly in a mass ratio of 10:45:1, and stir at 50 °C for 35 min to obtain stream B; mix stream A and stream B evenly and stir at 80 °C for 60 min to obtain the second binder.

[0078] Dry the second slurry at 120 °C for 12 h and calcine it at 450 °C for 6 h to obtain the material, mix it evenly with rectorite, the second binder, sodium carbonate, and water to form the third slurry. Passivate it at 40 °C for 20 min; then spray-form it, dry it at 120 °C for 12 h, and calcine it at 400 °C for 6 h to obtain the carbon dioxide adsorbent.

[0079] The specific surface area of the adsorbent is 182 m 2 / g, the mesopores account for 42.5% of the total pores, the active component loading is 28.7%, and the attrition index is 2.5%. The CO adsorption capacity of the fresh adsorbent is 2.18 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 2.02 mmol / g. For the gas after adsorption, the CO removal rate is 93.0%. 2 The CO adsorption capacity of the fresh adsorbent is 2.18 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 2.02 mmol / g. For the gas after adsorption, the CO removal rate is 93.0%. 2 The CO adsorption capacity of the fresh adsorbent is 2.18 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 2.02 mmol / g. For the gas after adsorption, the CO removal rate is 93.0%. 2 The CO adsorption capacity of the fresh adsorbent is 2.18 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 2.02 mmol / g. For the gas after adsorption, the CO removal rate is 93.0%.

[0080] Example 3

[0081] Mix alumina microspheres (particle size distribution D50 is 68 μm, specific surface area is 193 m 2 / g), potassium hydroxide solution (0.1 mol / L), and water evenly in a mass ratio of 25:1.5:100, and stir at 80 °C for 40 min to form a first slurry.

[0082] Dry the first slurry at 120 °C for 12 h and calcine it at 650 °C for 6 h to obtain a material. Mix acetic acid solution (0.02 mol / L) and water evenly in a mass ratio of 1:100, and stir with the material obtained after calcination at 55 °C for 60 min to form a second slurry.

[0083] Mix alumina, kaolin, and sodium hydroxide solution (0.7 mol / L) evenly in a mass ratio of 1:0.5:3.5, and stir at 45 °C for 50 min to obtain stream A; mix sodium carbonate, nitric acid (0.5 mol / L), and glycerol fatty acid ester evenly in a mass ratio of 5:65:1, and stir at 50 °C for 35 min to obtain stream B; mix stream A and stream B evenly and stir at 80 °C for 60 min to obtain a second binder.

[0084] Dry the second slurry at 120 °C for 12 h and calcine it at 450 °C for 6 h to obtain a material, and mix it evenly with kaolin, the second binder, sodium bicarbonate, and water to form a third slurry. Passivate it at 40 °C for 20 min; then spray-form it, dry it at 120 °C for 12 h, and calcine it at 400 °C for 6 h to obtain a carbon dioxide adsorbent.

[0085] The specific surface area of the adsorbent is 186 m 2 / g, the mesopores account for 53.1% of the total pores, the active component loading is 34.8%, and the attrition index is 3.8%. The CO 2 adsorption capacity of the fresh adsorbent is 2.29 mmol / g, and the CO 2 adsorption capacity of the regenerated adsorbent is 2.13 mmol / g. For the gas after adsorption, the CO 2 removal rate is 95.1%.

[0086] Example 4

[0087] Mix alumina microspheres (particle size distribution D50 is 68 μm, specific surface area is 193 m 2 / g), potassium carbonate solution (0.1 mol / L), and water evenly in a mass ratio of 20:0.5:100, and stir at 80 °C for 40 min to form a first slurry.

[0088] The first slurry was dried at 120 °C for 12 h and then calcined at 650 °C for 6 h to obtain a material. A nitric acid solution (0.02 mol / L) and water were mixed evenly according to a mass ratio of 3:100, and then mixed with the calcined material and stirred at 55 °C for 60 min to form a second slurry.

[0089] Aluminum oxide, kaolin, and a potassium hydroxide solution (0.7 mol / L) were mixed evenly according to a mass ratio of 1:0.7:2.5 and stirred at 45 °C for 50 min to obtain stream A; sodium bicarbonate, phosphoric acid (0.3 mol / L), and fatty alcohol polyoxyethylene ether were mixed evenly according to a mass ratio of 8:55:1 and stirred at 50 °C for 35 min to obtain stream B; stream A and stream B were mixed evenly and stirred at 80 °C for 60 min to obtain a second binder.

[0090] The second slurry was dried at 120 °C for 12 h and then calcined at 450 °C for 6 h to obtain a material, which was mixed evenly with kaolin, the second binder, potassium carbonate, and water to form a third slurry. It was passivated at 40 °C for 20 min; then it was spray-molded, dried at 120 °C for 12 h, and calcined at 400 °C for 6 h to obtain a carbon dioxide adsorbent.

[0091] The specific surface area of the adsorbent was 196 m 2 / g, the mesopores accounted for 50.4% of the total pores, the loading amount of the active component was 30.6%, and the attrition index was 3.5%. The CO 2 adsorption capacity of the fresh adsorbent was 2.23 mmol / g, and the CO 2 adsorption capacity of the regenerated adsorbent was 2.09 mmol / g. For the gas after adsorption, the CO 2 removal rate was 94.8%.

[0092] Comparative Example 1

[0093] Using alumina microspheres (particle size distribution D50 was 68 μm, specific surface area was 193 m 2 / g) as the carrier and potassium carbonate as the active component, a supported adsorbent with a loading amount of 30% was prepared by equal-volume impregnation. The drying, calcination temperature, and performance test were the same as in Example 4. The CO 2 adsorption capacity of the fresh adsorbent was 1.63 mmol / g, and the CO 2 adsorption capacity of the regenerated adsorbent was 1.04 mmol / g.

[0094] Comparative Example 2

[0095] Using alumina microspheres (particle size distribution D50 was 68 μm, specific surface area was 193 m 2Using γ -Al₂O₃ as the carrier and potassium carbonate as the active component, the equal - volume impregnation preparation method was adopted. First, 10% was loaded, then dried at 120 °C for 12 h and calcined at 400 °C for 6 h; this was carried out three times in total to prepare a supported adsorbent with a loading amount of 30%. The drying, calcination temperature, and performance testing were the same as in Example 4. The CO adsorption amount of the fresh adsorbent was 0.85 mmol / g, and the CO adsorption amount of the regenerated adsorbent was 0.56 mmol / g. 2 The CO adsorption amount of the fresh adsorbent was 0.85 mmol / g, and the CO adsorption amount of the regenerated adsorbent was 0.56 mmol / g. 2 The CO adsorption amount of the regenerated adsorbent was 0.56 mmol / g.

[0096] Comparative Example 3

[0097] It was basically the same as Example 1, except that the second binder was not used. The specific surface area of the adsorbent was 172 m² / g, the mesopores accounted for 28.6% of the total pores, the loading amount of the active component was 32.2%, and the attrition index was 4.9%. The CO adsorption amount of the fresh adsorbent was 1.83 mmol / g, and the CO adsorption amount of the regenerated adsorbent was 1.61 mmol / g. The CO removal rate of the gas after adsorption was 81.4%. 2 The specific surface area of the adsorbent was 172 m² / g, the mesopores accounted for 28.6% of the total pores, the loading amount of the active component was 32.2%, and the attrition index was 4.9%. The CO adsorption amount of the fresh adsorbent was 1.83 mmol / g, and the CO adsorption amount of the regenerated adsorbent was 1.61 mmol / g. After the gas passed through the adsorbent, the CO removal rate was 81.4%. 2 The CO adsorption amount of the fresh adsorbent was 1.83 mmol / g, and the CO adsorption amount of the regenerated adsorbent was 1.61 mmol / g. 2 The CO adsorption amount of the regenerated adsorbent was 1.61 mmol / g. After the gas passed through the adsorbent, the CO removal rate was 81.4%. 2 The CO removal rate was 81.4%.

[0098] Comparative Example 4

[0099] Aluminum oxide microspheres (particle size distribution D50 was 68 μm, specific surface area was 193 m² / g), sodium hydroxide solution (0.1 mol / L), and water were mixed evenly according to a mass ratio of 6:4:100, and stirred at 80 °C for 40 min to form the first slurry. 2 Aluminum oxide microspheres (particle size distribution D50 was 68 μm, specific surface area was 193 m² / g), sodium hydroxide solution (0.1 mol / L), and water were mixed evenly according to a mass ratio of 6:4:100, and stirred at 80 °C for 40 min to form the first slurry.

[0100] Pseudoboehmite, bentonite, and sodium hydroxide solution (0.6 mol / L) were mixed evenly according to a mass ratio of 1:0.2:4.5, and stirred at 45 °C for 50 min to obtain stream A; potassium carbonate, nitric acid (0.2 mol / L), and sodium stearate were mixed evenly according to a mass ratio of 3:70:1, and stirred at 50 °C for 35 min to obtain stream B; stream A and stream B were mixed evenly and stirred at 80 °C for 60 min to obtain the second binder.

[0101] The first slurry was dried at 120 °C for 12 h and calcined at 700 °C for 4 h to obtain a material, which was mixed evenly with silica sol, the second binder, potassium bicarbonate, and water to form the third slurry. It was passivated at 40 °C for 20 min; then spray - formed, dried at 120 °C for 12 h, and calcined at 400 °C for 6 h to obtain a carbon dioxide adsorbent.

[0102] The specific surface area of the adsorbent was 165 m² / g 2 / g, the mesopores account for 25.2% of the total pores, the active component loading is 31.9%, and the attrition index is 5.6%. The CO adsorption capacity of the fresh adsorbent is 1.71 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 1.56 mmol / g. For the gas after adsorption, the CO removal rate is 78.5%. 2 The CO adsorption capacity of the fresh adsorbent is 1.71 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 1.56 mmol / g. For the gas after adsorption, the CO removal rate is 78.5%. 2 The CO adsorption capacity of the fresh adsorbent is 1.71 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 1.56 mmol / g. For the gas after adsorption, the CO removal rate is 78.5%. 2 The CO adsorption capacity of the fresh adsorbent is 1.71 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 1.56 mmol / g. For the gas after adsorption, the CO removal rate is 78.5%.

[0103] Comparative Example 5

[0104] Mix the hydrochloric acid solution (0.02 mol / L) and water evenly according to the mass ratio of 2:100, and stir with alumina microspheres (particle size distribution D50 is 68 μm, specific surface area is 193 m 2 / g) at 55 °C for 60 min to form a second slurry.

[0105] Mix pseudoboehmite, bentonite and sodium hydroxide solution (0.6 mol / L) evenly according to the mass ratio of 1:0.2:4.5, and stir at 45 °C for 50 min to obtain stream A; mix potassium carbonate, nitric acid (0.2 mol / L) and sodium stearate evenly according to the mass ratio of 3:70:1, and stir at 50 °C for 35 min to obtain stream B; mix stream A and stream B evenly, and stir at 80 °C for 60 min to obtain a second binder.

[0106] Dry the second slurry at 120 °C for 12 h, calcine it at 450 °C for 6 h to obtain a material, mix it evenly with silica sol, the second binder, potassium bicarbonate and water to form a third slurry. Passivate it at 40 °C for 20 min; then spray it into shape, dry it at 120 °C for 12 h, and calcine it at 400 °C for 6 h to obtain a carbon dioxide adsorbent.

[0107] The specific surface area of the adsorbent is 158 m 2 / g, the mesopores account for 18.7% of the total pores, the active component loading is 32.1%, and the attrition index is 5.9%. The CO adsorption capacity of the fresh adsorbent is 1.75 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 1.48 mmol / g. For the gas after adsorption, the CO removal rate is 64.8%. 2 The CO adsorption capacity of the fresh adsorbent is 1.75 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 1.48 mmol / g. For the gas after adsorption, the CO removal rate is 64.8%. 2 The CO adsorption capacity of the fresh adsorbent is 1.75 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 1.48 mmol / g. For the gas after adsorption, the CO removal rate is 64.8%. 2 The CO adsorption capacity of the fresh adsorbent is 1.75 mmol / g, and the CO adsorption capacity of the regenerated adsorbent is 1.48 mmol / g. For the gas after adsorption, the CO removal rate is 64.8%.

Claims

1. A carbon dioxide adsorbent, the adsorbent comprising a carrier and an active component, wherein, the carrier is one or more of alumina microspheres, silica-alumina spheres, and silica spheres, preferably alumina microspheres; the active component is one or more of carbonates formed by Group IA elements, selected from one or more of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, lithium carbonate, and lithium bicarbonate, preferably one or more of potassium carbonate and sodium carbonate.

2. The carbon dioxide adsorbent according to claim 1, characterized in that: The D50 of the particle size distribution of the carbon dioxide adsorbent is 100 - 300 μm, preferably 150 - 160 μm; the specific surface area is 10 - 500 m 2 / g, preferably 50 - 300 m 2 / g, more preferably 100 - 200 m 2 / g.

3. The carbon dioxide adsorbent according to claim 1, characterized in that: The proportion of the pore volume of the mesopores in the carbon dioxide adsorbent to the total pore volume is 30 - 90%, wherein the mesopores are pores with a pore diameter greater than 2 nm and less than 100 nm.

4. The carbon dioxide adsorbent according to claim 1, characterized in that: Based on the weight of the carbon dioxide adsorbent, the content of the active component in the carbon dioxide adsorbent is 1 - 50%, preferably 5 - 35%.

5. The carbon dioxide adsorbent according to claim 1, characterized in that: The attrition index of the carbon dioxide adsorbent is 0.1 - 10%, preferably 0.5 - 5%.

6. A method for preparing a carbon dioxide adsorbent, comprising the following steps: (1) Mix alumina microspheres, an alkali, and water evenly to obtain a first slurry; (2) Subject the first slurry obtained in step (1) to drying and calcination treatments, and then mix it evenly with an acid and water to obtain a second slurry; (3) Subject the second slurry obtained in step (2) to drying and calcination treatments, and then mix it evenly with a first binder, a second binder, an active component, and water to obtain a third slurry; The first binder is selected from one or more of silica sol, aluminum sol, kaolin, sepiolite, diatomite, rectorite, montmorillonite, and bentonite; (4) The third slurry obtained in step (3) is dried and calcined to obtain a carbon dioxide adsorbent.

7. The method for preparing a carbon dioxide adsorbent according to claim 6, characterized in that: The alkali in step (1) is an alkali metal compound, the alkali metal is selected from at least one of lithium, sodium, and potassium, and the alkali metal compound is selected from one or more of potassium hydroxide, sodium hydroxide, potassium carbonate, and sodium carbonate, preferably sodium carbonate.

8. The method for preparing a carbon dioxide adsorbent according to claim 6, characterized in that: The size of the alumina microspheres described in step (1) is 5 - 500 μm, preferably 10 - 500 μm, more preferably 20 - 50 μm, wherein the particle size distribution D50 is 50 - 200 μm, preferably 30 - 80 μm; the specific surface area of the alumina microspheres is 5 - 500 m 2 / g, preferably 10 - 300 m 2 / g, more preferably 50 - 200 m 2 / g.

9. The method for preparing a carbon dioxide adsorbent according to claim 6, characterized in that: The amounts of the alumina microspheres, alkali, and water in step (1) are (1 - 50):(0.1 - 20):100, preferably (5 - 30):(0.1 - 5):

100.

10. The method for preparing a carbon dioxide adsorbent according to claim 6, characterized in that: The treatment temperature in step (1) is 30 - 100 °C, preferably 50 - 90 °C.

11. The method for preparing a carbon dioxide adsorbent according to claim 6, characterized in that: The calcination in step (2) is carried out under the following conditions: the calcination temperature is 500 - 1200 °C, preferably 600 - 800 °C; the calcination time is 0.5 - 48 h, preferably 1 - 12 h; the calcination is carried out in the presence of an inert atmosphere.

12. The method for preparing a carbon dioxide adsorbent according to claim 6, characterized in that: The drying in step (2) is carried out under the following drying conditions: the drying temperature is 50 - 300 °C, preferably 80 - 180 °C.

13. The method for preparing a carbon dioxide adsorbent according to claim 6, characterized in that: The acid in step (2) is one or more of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, carbonic acid, acetic acid, preferably one or more of hydrochloric acid, phosphoric acid, nitric acid, acetic acid.

14. The method for preparing a carbon dioxide adsorbent according to claim 6, characterized in that: The calcination in step (3) is carried out under the following operating conditions: the calcination temperature is 300 - 1000 °C, preferably 400 - 500 °C.

15. The method for preparing a carbon dioxide adsorbent according to claim 6, characterized in that: The first binder in step (3) is selected from one or more of silica sol, kaolin, rectorite, bentonite.

16. The method for preparing a carbon dioxide adsorbent according to claim 6, characterized in that: The active component in step (3) is one or more of the basic carbonates of the elements in the first main group of the periodic table, the basic acetates of the elements in the first main group, selected from one or more of potassium carbonate, potassium bicarbonate, potassium acetate, sodium carbonate, sodium bicarbonate, sodium acetate, lithium carbonate, lithium bicarbonate, lithium acetate, preferably one or more of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate.

17. The method for preparing a carbon dioxide adsorbent according to claim 6, characterized in that: The preparation method of the second binder in step (3) includes the following steps: (3.1) Mix an aluminum-containing compound, clay and an alkali solution evenly and carry out treatment to obtain a material stream A; (3.2) Mix a compound containing a Group IA metal element, an acid solution and a surfactant evenly and carry out treatment to obtain a material stream B; (3.3) Mix the material stream A and the material stream B evenly and carry out a reaction to obtain the second binder.

18. The method for preparing a carbon dioxide adsorbent according to claim 17, characterized in that: The aluminum-containing compound in step (3.1) is selected from one or more of alumina, aluminum hydroxide, pseudo-boehmite, preferably alumina.

19. The method for preparing a carbon dioxide adsorbent according to claim 17, characterized in that: The clay in step (3.1) is selected from one or more of bentonite, saponite, kaolin.

20. The method for preparing a carbon dioxide adsorbent according to claim 17, characterized in that: The alkali solution in step (3.1) is an inorganic alkali solution, selected from one or more of sodium hydroxide, potassium hydroxide.

21. The method for preparing a carbon dioxide adsorbent according to claim 17, characterized in that: In step (3.1), the mass ratio of the aluminum-containing compound, clay, and alkali solution is 1:(0.01 - 10):(0.1 - 20), preferably 1:(0.1 - 1):(1 - 5).

22. The method for preparing the carbon dioxide adsorbent according to claim 17, wherein: The treatment conditions in step (3.1) are as follows: the treatment temperature is 30 - 100 °C, preferably 40 - 50 °C.

23. The method for preparing the carbon dioxide adsorbent according to claim 17, wherein: The compound containing a Group IA metal element of the periodic table in step (3.2) is one or more of an alkaline carbonate and an alkaline acetate formed by a Group IA element of the periodic table, selected from one or more of potassium carbonate, potassium bicarbonate, potassium acetate, sodium carbonate, sodium bicarbonate, sodium acetate, lithium carbonate, lithium bicarbonate, and lithium acetate, preferably one or more of potassium carbonate, potassium bicarbonate, sodium carbonate, and sodium bicarbonate.

24. The method for preparing the carbon dioxide adsorbent according to claim 17, wherein: The mass ratio of the compound containing a Group IA metal element of the periodic table, acid solution, and surfactant in step (3.2) is (0.1 - 20):(20 - 100):1, preferably (1 - 10):(40 - 80):

1.

25. The method for preparing the carbon dioxide adsorbent according to claim 17, wherein: The surfactant in step (3.2) is one or more of an anionic surfactant and a non-ionic surfactant. The anionic surfactant is one or more of carboxylates, sulfonates, sulfates, and phosphates, selected from one or more of sodium stearate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, potassium hexadecyl phosphate, and sodium lauroyl sarcosinate; the non-ionic surfactant is one or more of polyoxyethylene derivatives, alkyl alcohol amides, polyol monofatty acid esters, alkylamine oxides, and N-alkyl pyrrolidones, selected from one or more of fatty alcohol polyoxyethylene ethers, coconut fatty acid diethylamide, glycerol fatty acid esters, dodecyldimethylamine oxide, and lauryl pyrrolidone.

26. The method for preparing the carbon dioxide adsorbent according to claim 17, wherein: The acid solution in step (3.2) is an inorganic acid solution and / or an organic acid solution, selected from one or more of nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, and formic acid solution, preferably one or more of nitric acid, hydrochloric acid, and phosphoric acid, more preferably nitric acid.

27. The method for preparing the carbon dioxide adsorbent according to claim 17, wherein: The treatment conditions in step (3.2) are as follows: the treatment temperature is 30 - 100 °C, preferably 40 - 50 °C; the treatment conditions in step (3.3) are as follows: the treatment temperature is 30 - 100 °C, preferably 50 - 90 °C.

28. The method for preparing the carbon dioxide adsorbent according to claim 6, wherein: The temperature for the mixed treatment in step (3) is 30 - 100 °C, preferably 40 - 60 °C.

29. The preparation method of the carbon dioxide adsorbent according to claim 6, characterized in that: before the drying of the third slurry in step (4), passivation treatment is carried out. The passivation treatment is to treat the third slurry at 10 - 100 °C, preferably 30 - 50 °C for a period of time, and the treatment time is 5 - 60 min, preferably 10 - 30 min.

30. The preparation method of the carbon dioxide adsorbent according to claim 6, characterized in that: the drying temperature in step (4) is 100 - 300 °C, preferably 120 - 150 °C; the calcination temperature is 300 - 600 °C, preferably 350 - 400 °C; the calcination is carried out under an inert atmosphere condition.

31. The application of the carbon dioxide adsorbent according to any one of claims 1 - 5 or the carbon dioxide adsorbent obtained by using the preparation method according to any one of claims 6 - 30 in the carbon dioxide adsorption process.