Composite adsorbent with regular structure for hydrogen-rich tail gas and preparation method of composite adsorbent

Abstract

The invention belongs to the technical field of hydrogen recovery, and particularly relates to a regular-structure composite adsorbent for hydrogen-rich tail gas and a preparation method thereof.The regular-structure composite adsorbent for the hydrogen-rich tail gas is sequentially overlapped according to the flowing direction of the hydrogen-containing tail gas, and the composite adsorbent is composed of a dehydration adsorbent, an O2 adsorbent, a CO2 adsorbent and a CO adsorbent in sequence; wherein the dehydration adsorbent is activated aluminum oxide, the O2 adsorbent is an Ag < + > modified Li-LSX molecular sieve, the CO2 adsorbent is prepared from nanocrystalline sodium mordenite, sodium silicate, metakaolin and sodium hydroxide, and the CO adsorbent is a Cu (I) / 4A molecular sieve adsorbent; the dehydration adsorbent is symmetrically distributed in the composite adsorbent, and the O2 adsorbent, the CO2 adsorbent and the CO adsorbent are of a laminated structure on the whole; the adsorbent has high adsorption capacity, high selectivity and good regeneration performance on impurities in hydrogen-rich tail gas, and the recovery purity and recovery rate of hydrogen can be effectively improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen recovery, and particularly relates to a regular structure composite adsorbent for hydrogen-rich tail gas and a preparation method thereof. BACKGROUND

[0002] In many chemical, petroleum refining, coal chemical and other industrial production processes, a large amount of hydrogen-rich tail gas will be produced, such as in catalytic reforming, hydrocracking, coke oven gas treatment and other processes. In addition to hydrogen, these hydrogen-rich tail gases also contain carbon monoxide, carbon dioxide, methane, nitrogen, water vapor and a small amount of hydrogen sulfide and other impurities. Hydrogen, as an important clean energy and chemical raw material, has a wide application prospect. Recovering high-purity hydrogen from hydrogen-rich tail gas is of great significance for improving resource utilization, reducing production costs and reducing environmental pollution.

[0003] At present, the technologies for separating hydrogen mainly include cryogenic separation method, membrane separation method and pressure swing adsorption method. The cryogenic separation method has large equipment investment, high energy consumption and complex operation; although the membrane separation method has relatively simple equipment, the cost of the membrane is high, and the separation efficiency and selectivity are limited by the membrane material. The pressure swing adsorption method is widely used because of its simple process, flexible operation, low energy consumption, high product purity and other advantages, but the existing adsorbents have limited adsorption capacity for impurities, low selectivity and poor regeneration performance when processing process hydrogen-rich tail gas, which leads to the difficulty in meeting the higher requirements of industrial production in terms of hydrogen recovery efficiency and purity. Therefore, developing a high-efficiency hydrogen-rich tail gas adsorbent has become a technical problem to be solved in the field. SUMMARY

[0004] The purpose of the present application is to provide a regular structure composite adsorbent for hydrogen-rich tail gas and a preparation method thereof. The adsorbent has high adsorption capacity, high selectivity and good regeneration performance for impurities in hydrogen-rich tail gas, and can effectively improve the recovery purity and recovery rate of hydrogen.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions: In a first aspect, the present application provides a regular structure composite adsorbent for hydrogen-rich tail gas, which is stacked in sequence according to the flow direction of hydrogen-containing tail gas, and the order of the composite adsorbent is: dehydration adsorbent, O2 adsorbent, CO2 adsorbent, CO adsorbent; The dehydration adsorbent is active alumina, the O2 adsorbent is Ag + modified Li-LSX molecular sieve, the CO2 adsorbent is prepared from nanocrystalline sodium mordenite, sodium silicate, metakaolin and sodium hydroxide, and the CO adsorbent is Cu(I) / 4A molecular sieve adsorbent; In the composition of the composite adsorbent, the volume ratio of the dehydration adsorbent is 30-40%, the volume ratio of the O2 adsorbent is 30-40%, the volume ratio of the CO2 adsorbent is 10-20%, and the volume ratio of the CO adsorbent is 10-20%. The dehydration adsorbent is symmetrically distributed in the composite adsorbent, and the O2 adsorbent, the CO2 adsorbent, and the CO adsorbent are stacked in the whole and repeated 2-3 times.

[0006] Further, the specific surface area of the active alumina is 240-400 m 2 / g, and the pore volume is 0.8-1.5 ml / g.

[0007] Further, the Ag + The preparation method of the modified Li-LSX molecular sieve is as follows: the Ag + solution with a concentration of 0.3-0.6 mol / L is added to the Li + solution with a concentration of 1-1.5 mol / L, the temperature is raised to 60-120℃, the reaction is carried out for 70-160 min, the mixture is dried in an oven at 110℃ for 3-4 hours, the temperature is raised to 200℃, the temperature is maintained for 1-3 hours, the temperature is raised to 400℃, and the temperature is maintained for 1-3 hours, to prepare the Ag + modified Li-LSX molecular sieve.

[0008] Further, the preparation method of the CO2 adsorbent is as follows: (1) γ-aminobutyric acid or L-lysine, sodium hydroxide, silica sol, sodium alumininate, deionized water, and sodium mordenite are mixed, and the mass percentage of the six in the mixture is 3-10%, 10-15%, 10-20%, 2-5%, 40-70%, and 2-5%, respectively; the mixture is transferred to a high-pressure kettle lined with Teflon, heated at 80℃ for 24 hours, then the temperature is raised to 160℃, and rotated at 60 rpm for 24 hours; after the high-pressure kettle is cooled to room temperature, the separated solid product is washed with deionized water until the washing liquid is neutral, and the washed solid product is dried at room temperature overnight to obtain nanocrystalline sodium mordenite; (2) mixing sodium hydroxide, fumed silica and deionized water to obtain a sodium silicate solution, the mass percentage of the three in the mixture being 5-20%, 15-30% and 50-70% respectively; mixing metakaolin, NaOH and deionized water to hydrate nanocrystalline sodium mordenite and adding the same to the sodium silicate solution; the mass percentage of the four in the mixture being 40-60%, 10-20%, 5-15% and 15-25% respectively; casting the uniformly mixed slurry into a silica mold, curing at 80°C for 24 hours in a closed environment; then demolding and continuing to cure at 80°C for 24 hours to obtain the CO2 adsorbent.

[0009] Further, the preparation method of the Cu(I) / 4A molecular sieve adsorbent is as follows: mixing copper nitrate 0.2-0.5g, tetramethylammonium hydroxide 30-60g, aluminum hydroxide 0.5-5g, aluminum chloride 2-8g, tetraethyl orthosilicate 2-6g and deionized water 10-50g, and then sequentially performing crystallization reaction and reduction reaction to prepare the Cu(I) / 4A molecular sieve; wherein the crystallization reaction temperature is 90-120°C and the reaction time is 180-220min; the reduction reaction conditions are as follows: adding 0.2g of chromium trichloride and reacting at 180-230°C for 200min.

[0010] In the second aspect of the present application, the preparation method of the regular structure composite adsorbent for hydrogen-rich tail gas is provided, and the preparation method comprises preparing a dehydration bed and an adsorbent bed respectively; wherein the preparation method of the dehydration bed is as follows: the active alumina and aramid fiber in the first aspect are jointly added into polyurethane emulsion with a mass fraction of 40%, then water is added, 1L of water corresponds to 1000g of the mixture, and then the mixture is dispersed by a dispersing machine to form a uniform mixed slurry; the slurry is placed in a vacuum pug mill for aging for 20h, then is placed in a hydraulic extrusion molding machine for extrusion, the pressure is 16MPa, the extrusion molded sample is dried at 100°C for 6h, and the corresponding dehydration bed is obtained after vacuum activation at 140°C for 4h; The preparation method of the adsorbent bed is as follows: the adsorbent and aramid fiber are jointly added into polyurethane emulsion with a mass fraction of 40% to form a uniform slurry, then water is added, 1L of water corresponds to 1000g of the mixture, and then the mixture is dispersed by a dispersing machine to form a uniform mixed slurry; the slurry is placed in a vacuum pug mill for aging for 20h, then is placed in a hydraulic extrusion molding machine for extrusion, the pressure is 16MPa, the extrusion molded sample is dried at 100°C for 6h, and the corresponding adsorbent bed is obtained after vacuum activation at 140°C for 4h; the adsorbent is the O2 adsorbent in the first aspect, the CO2 adsorbent in the first aspect or the CO adsorbent Cu(I) / 4A molecular sieve adsorbent in the first aspect.

[0011] The beneficial effects of the present application are as follows: (1) The adsorbent of the application is a composite adsorbent constructed by regular structure adsorbents, and has good adsorption performance for impurities such as O2, H2O, CO and CO2 in the hydrogen-rich tail gas. Meanwhile, the composite adsorbent adopts a laminated structure, which not only improves the specific surface area and pore structure stability of the adsorbent, but also enhances the selectivity to hydrogen, so that hydrogen can be more efficiently separated from the hydrogen-rich tail gas.

[0012] (2) The preparation method of the adsorbent is simple and easy to operate, raw materials are easy to obtain, and the cost is low, which is suitable for industrial large-scale production.

[0013] (3) The adsorbent has good regeneration performance in the application process, and can still maintain high adsorption capacity and selectivity after multiple adsorption-regeneration cycles, which can effectively reduce the process operation cost and improve the economic benefit. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 Figure 1 is a structural schematic diagram of a tail gas adsorption tower of Embodiment 1 of the application; In the figure: 1, dehydrating adsorbent; 2, O2 adsorbent; 3, CO2 adsorbent; 4, CO adsorbent. DETAILED DESCRIPTION

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings described in the following can only be some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0016] The application will be described in detail below in combination with the drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the application are not limited to the following embodiments.

[0017] Embodiment 1: A regular structure composite adsorbent for hydrogen-rich tail gas, as shown in Figure 1 The composite adsorbent has a dehydrating bed at both ends, and the volume ratio of the dehydrating beds at both ends is 1:1. The middle part is composed of two adsorbent bed groups connected in sequence. In each adsorbent bed group, O2 adsorption bed, CO2 adsorption bed and CO adsorption bed are distributed in sequence according to the direction of gas flowing in and out. Compared with the total volume of the composite adsorbent, the two dehydrating beds at both ends account for 38% of the total volume, the O2 adsorption bed accounts for 38% of the total volume, the CO2 adsorption bed accounts for 12% of the total volume, and the CO adsorption bed accounts for 12% of the total volume. The overall internal diffusion distance of the composite adsorbent is 0.2mm, and the porosity is 60%.

[0018] The dehydrating adsorbent 1 is active alumina, the specific surface area of the active alumina is greater than 280m2 / g, pore volume 1 ml / g; in this example, the preparation method of the dehydrated bed is as follows: The dehydrated adsorbent 1 and aramid fibers are added together into a polyurethane emulsion with a mass fraction of 40% to form a uniform slurry, then water is added, 1 L of water corresponding to 1000 g of the mixture, and then a dispersion machine is used for dispersion to form a uniform mixed slurry; the slurry is placed in a vacuum pug mill for aging for 20 h, and then is placed into a hydraulic extrusion molding machine for extrusion at a pressure of 16 MPa; the extrusion molded sample is dried at 100°C for 6 h, and then is subjected to vacuum activation at 140°C for 4 hours to obtain the dehydrated bed.

[0019] In this example, the preparation method of the O2 adsorption bed is as follows: (1) First, the O2 adsorbent 2 is prepared: the O2 adsorbent 2 is Ag + The modified Li-LSX molecular sieve is prepared as follows: Ag + A silver nitrate solution with a concentration of 0.3-0.6 mol / L is added to a Li + The concentration of the Li-LSX molecular sieve aqueous solution is 1-1.5 mol / L, and the solid-liquid ratio of the former to the latter is 20:1; the temperature is raised to 60-120°C, and the reaction is carried out for 70-160 min; the sample is dried in an oven at 110°C for 3-4 hours; the temperature is raised to 200°C, and the sample is kept at this temperature for 1-3 hours; the temperature is raised to 400°C, and the sample is kept at this temperature for 1-3 hours to prepare Ag + modified Li-LSX molecular sieve; (2) The O2 adsorption bed is prepared: the O2 adsorbent 2 and aramid fibers are added together into a polyurethane emulsion with a mass fraction of 40% to form a uniform slurry, then water is added, 1 L of water corresponding to 1000 g of the mixture, and then a dispersion machine is used for dispersion to form a uniform mixed slurry; the slurry is placed in a vacuum pug mill for aging for 20 h, and then is placed into a hydraulic extrusion molding machine for extrusion at a pressure of 16 MPa; the extrusion molded sample is dried at 100°C for 6 h, and then is subjected to vacuum activation at 140°C for 4 hours to obtain the O2 adsorption bed.

[0020] In this example, the preparation method of the CO2 adsorption bed is as follows: (1) First, the CO2 adsorbent 3 is prepared: Take 3.03 g of γ-aminobutyric acid with a purity of 99% and add to 45.57 g of deionized water, stirring to completely dissolve; then slowly add 16 g of a 50% mass fraction sodium hydroxide solution, stirring to uniform, then sequentially add 25 g of silica sol (40% mass fraction of fumed silica), 2.4 g of sodium metaaluminate, 1 g of sodium mordenite with a purity of 99.9%, and continue stirring at room temperature for 12 hours to form a uniform reaction mixture. Transfer the mixture to a Teflon-lined autoclave, heat at 80°C for 24 hours to initially cause a chemical reaction in the reaction system; then increase the temperature to 160°C and rotate at a speed of 60 rpm for 1 day to promote the crystalline growth of the nanocrystalline sodium mordenite. After the reaction is complete, cool the autoclave to room temperature, separate the solid product from the reaction mixture by filtration, and wash the separated solid product with deionized water until the washing liquid is neutral to remove impurities and unreacted raw materials remaining on the surface of the product. Dry the washed solid product at room temperature overnight to obtain nanocrystalline sodium mordenite.

[0021] Take 20 g of sodium hydroxide solid and dissolve in 100 g of deionized water, then add 35 g of 99.8% fumed silica and react thoroughly under magnetic stirring to obtain a sodium silicate solution. Take 50 g of 1200 mesh metakaolin (SiO2=55%, Al2O3=39%) and 12 g of 98% NaOH, add to the sodium silicate solution and stir to uniform; add 10 g of deionized water to the hydrated 20 g of nanocrystalline sodium mordenite and add to the above mixture and mechanically stir for 10 minutes. Pour the uniformly mixed slurry into a silicon mold and solidify in a closed environment at 80°C for 24 hours; then demold and continue to solidify at 80°C for another 24 hours; prepare CO2 adsorbent 3 according to the above conditions.

[0022] (2) Preparation of CO2 adsorption bed: the preparation method is the same as that of O2 adsorption bed, which will not be repeated here.

[0023] In this embodiment, the preparation method of the CO adsorption bed is as follows: (1) First, prepare CO adsorbent 4: CO adsorbent 4 is a Cu(I) / 4A molecular sieve adsorbent, which is prepared by mixing 0.2 g of copper nitrate, 50 g of tetramethylammonium hydroxide, 0.5 g of aluminum hydroxide, 4 g of aluminum chloride, 4 g of tetraethyl orthosilicate, and 10 g of deionized water, and then sequentially performing a crystallization reaction and a reduction reaction; the crystallization reaction temperature is 90-120°C and the reaction time is 180-220 min; the reduction reaction conditions are: add 0.2 g of chromium chloride and react at 180-230°C for 200 min.

[0024] (2) Preparation of CO adsorption bed: the preparation method is the same as that of O2 adsorption bed, which will not be repeated here.

[0025] The composite adsorbent obtained in this example was used to separate impurities from hydrogen-containing tail gas. The contents of O2, H2O, CO, and CO2 in the hydrogen-containing tail gas before separation were 400 ppm, 300 ppm, 50 ppm, and 30 ppm, respectively. After purification, the impurity contents of O2, H2O, CO, and CO2 in the product gas were reduced to less than 0.8 ppm, less than 0.5 ppm, less than 0.5 ppm, and less than 0.7 ppm, respectively.

[0026] Example 2: Compared with Example 1, the difference lies in that 4.07 g of L-lysine with a purity of 98% is weighed and used as a crystal growth inhibitor instead of γ-aminobutyric acid; other matters are the same as those in Example 1.

[0027] The composite adsorbent obtained in this example was used to separate impurities from hydrogen-containing tail gas. The contents of O2, H2O, CO, and CO2 in the hydrogen-containing tail gas before separation were 400 ppm, 300 ppm, 50 ppm, and 30 ppm, respectively. After purification, the impurity contents of O2, H2O, CO, and CO2 in the product gas were reduced to less than 0.8 ppm, less than 0.5 ppm, less than 0.5 ppm, and less than 0.7 ppm, respectively.

[0028] Comparative Example 1: Compared with Example 1, the difference lies in that the CO2 adsorbent 3 is prepared by the following method: 20 g of sodium hydroxide solid is dissolved in 100 g of deionized water, and then 35 g of 99.8% fumed silica is added and fully reacted under magnetic stirring to obtain a sodium silicate solution. 50 g of 1200 mesh metakaolin (SiO2=55%, Al2O3=39%) and 12 g of 98% NaOH are weighed and added to the sodium silicate solution and stirred uniformly; 10 g of deionized water is mixed with 20 g of hydrated nanocrystalline sodium mordenite and added to the above mixture, and mechanically stirred for 10 minutes. The uniformly mixed slurry is cast into a silicon mold and cured in a closed environment at 80°C for 24 hours; then demolded and further cured at 80°C for 24 hours; the CO2 adsorbent 3 is prepared according to the above conditions. Other matters are the same as those in Example 1.

[0029] The composite adsorbent obtained in this example was used to separate impurities from hydrogen-containing tail gas. The contents of O2, H2O, CO, and CO2 in the hydrogen-containing tail gas before separation were 400 ppm, 300 ppm, 50 ppm, and 30 ppm, respectively. After purification, the impurity contents of O2, H2O, CO, and CO2 in the product gas were reduced to less than 0.8 ppm, less than 0.5 ppm, less than 0.5 ppm, and less than 1.8 ppm, respectively.

[0030] Comparative Example 2: A regular structure composite adsorbent for hydrogen-rich tail gas, the regular structure composite adsorbent is composed in the order of: dehydration adsorbent 1, O2 adsorbent 2, CO2 adsorbent 3, CO adsorbent 4. The composite adsorbent is composed of dehydration adsorbent 1 at both ends, the volume ratio of the dehydration adsorbent 1 at both ends is 1:1, and the O2 adsorbent 2, the CO2 adsorbent 3 and the CO adsorbent 4 are distributed in the middle according to the direction of gas entering and flowing out. Compared with the total volume of the composite adsorbent, the total volume ratio of the two dehydration adsorbents 1 at both ends is 38%, the volume ratio of the O2 adsorbent 2 is 38%, the volume ratio of the CO2 adsorbent 3 is 12%, and the volume ratio of the CO adsorbent 4 is 12%. The internal diffusion distance of the whole composite adsorbent is 0.2 mm, and the porosity is 60%.

[0031] The dehydration adsorbent 1 is active alumina, the specific surface area of the active alumina is greater than 280 m 2 / g, and the pore volume is 1 ml / g. In this embodiment, the Ag + The modified Li-LSX molecular sieve is prepared by the following method: the Ag + The silver nitrate solution with a concentration of 0.3 mol / L is added to the Li + The Li-LSX molecular sieve aqueous solution with a concentration of 1.2 mol / L, the solid-liquid ratio of the former to the latter is 20:1, is heated to 100°C, and reacts for 100 min, dried in an oven at 110°C for 3 hours, heated to 200°C, kept for 2 hours, heated to 400°C, and kept for 2 hours, to prepare the Ag + modified Li-LSX molecular sieve. In this embodiment, the preparation method of the CO2 adsorbent 3 is as follows: The strip-shaped 5A particle molecular sieve is first dried at 100°C for 4 hours, then cooled to 60°C and impregnated with hexamethylene imine liquid for 3 hours, the mass ratio of the two is 5:4; 200g is taken out, the hexamethylene imine liquid is separated, and the mixture is left to stand at room temperature for 1 hour; 20g of a 25% silicon sol aqueous solution and 10g of a 0.05% calcium hydroxide aqueous solution are sprayed on the strip-shaped 5A particle molecular sieve, ammonia gas is introduced, and then dried and calcined to prepare a modified 5A molecular sieve with a pore size of less than 10 nm, the proportion of the number of pores to the total number of pores is 50%, i.e. the CO2 adsorbent 3 is obtained.

[0032] In the present embodiment, the CO adsorbent 4 is a Cu(I) / 4A molecular sieve adsorbent, which is prepared by mixing copper nitrate 0.2 g, tetramethylammonium hydroxide 50 g, aluminum hydroxide 0.5 g, aluminum chloride 4 g, tetraethyl orthosilicate 4 g and deionized water 10 g, and then sequentially performing a crystallization reaction and a reduction reaction, wherein the crystallization reaction temperature is 90-120 DEG C, and the reaction time is 180-220 min; the reduction reaction conditions are: adding 0.2 g of chromium chloride at 180-230 DEG C for 200 min.

[0033] The composite adsorbent obtained in the present embodiment is used to separate impurities from the hydrogen-containing tail gas, and the contents of O2, H2O, CO and CO2 in the hydrogen-containing tail gas before separation are 400 ppm, 300 ppm, 50 ppm and 30 ppm, respectively; after purification, the impurity contents in the product gas are reduced to less than 3 ppm, less than 4 ppm, less than 2 ppm and less than 2 ppm, respectively.

[0034] According to the data of the examples and comparative examples, the content of impurity gas in the hydrogen-containing tail gas treated by the composite adsorbent in Example 1 is significantly reduced, and the content is lower in Example 1 than in the control group, which means that the composite adsorbent provided by the present application can more thoroughly adsorb impurity gas and purify hydrogen. The preparation process and structural design of the composite adsorbent provided by the present application are optimized to achieve the best performance in hydrogen purification. The whole extrusion product of the adsorbent material raw powder is used as the core component. The whole extrusion process of the raw powder has the advantage of ensuring uniform distribution and close packing of the adsorbent material. In the extrusion process, the raw powder of the adsorbent material is melted and formed to finally shape a honeycomb-shaped adsorbent with regular channels and stable structure. This structure not only ensures the mechanical strength of the adsorbent, but also provides a large specific surface area and a developed pore structure, thereby providing sufficient adsorption capacity.

[0035] At the same time, the honeycomb structure can effectively reduce the bed resistance of the adsorbent and improve the rate and efficiency of gas passing through the adsorbent bed. In addition, the whole extrusion process of the raw powder also makes the manufacturing process of the adsorbent more simple and efficient. Compared with the preparation method of traditional granular adsorbents, the whole extrusion process can reduce the gap and friction between the adsorbent particles, thereby reducing the energy loss of gas flow.

[0036] The present application focuses on the research and development of new efficient hydrogen purification adsorbents, breaking through the limitations of traditional granular beds. By using the regular structure design and taking advantage of the light weight of hydrogen and the high separation coefficient characteristics of impurities, the void fraction of the adsorbent module is precisely controlled to be below 70%, preferably below 60%. While maintaining a high void fraction, the gas resistance drop is reduced and the internal diffusion distance is shortened by structure optimization, which synergistically improves the utilization rate of the adsorbent and the separation efficiency of hydrogen and impurities, exceeding that of the granular bed.

[0037] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and that variations, modifications, substitutions and changes can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. A composite shaped adsorbent for hydrogen-rich tail gas, characterized by, According to the hydrogen-containing tail gas flow is sequentially superimposed, the order of the composition of the composite adsorbent is: dehydration adsorbent, O2 adsorbent, CO2 adsorbent, CO adsorbent; wherein the dehydrating adsorbent is activated alumina and the O2 adsorbent is Ag + Modified Li-LSX molecular sieve, CO2 adsorbent prepared from nanocrystalline sodium mordenite, sodium silicate, metakaolin and sodium hydroxide, CO adsorbent is Cu(I) / 4A molecular sieve adsorbent; In the composition of the composite adsorbent, the volume ratio of the dehydration adsorbent is 30%-40%, the volume ratio of the O2 adsorbent is 30%-40%, the volume ratio of the CO2 adsorbent is 10%-20%, and the volume ratio of the CO adsorbent is 10%-20%; The dehydration adsorbent is symmetrically distributed in the composite adsorbent, and the O2 adsorbent, CO2 adsorbent and CO adsorbent are stacked in the whole, and repeated 2-3 times.

2. A composite adsorbent of regular structure for hydrogen-rich tail gas according to claim 1, characterized in that, The activated alumina has a specific surface area of 240-400 m 2 / g, and a pore volume of 0.8-1.5 ml / g.

3. A composite adsorbent of regular structure for hydrogen-rich tail gas according to claim 1, characterized in that, The Ag + The preparation method of the modified Li-LSX molecular sieve is as follows: Ag + The silver nitrate solution with the concentration of 0.3-0.6 mol / L is added into the Li + The aqueous solution of the Li-LSX molecular sieve with the concentration of 1-1.5 mol / L is added into the silver nitrate solution, and then the temperature is raised to 60-120 DEG C, the reaction is carried out for 70-160 min, the temperature is raised to 200 DEG C and kept for 1-3 hours, and then the temperature is raised to 400 DEG C and kept for 1-3 hours, so as to prepare the Ag + modified Li-LSX molecular sieve.

4. A composite adsorbent of regular structure for hydrogen-rich tail gas according to claim 1, characterized in that, The preparation method of the CO2 adsorbent is: (1) γ-aminobutyric acid or L-lysine, sodium hydroxide, silica sol, sodium metaaluminate, deionized water and sodium mordenite are mixed, and the mass percentage of the six in the mixture is 3-10%, 10-15%, 10-20%, 2-5%, 40-70% and 2-5% respectively; then the mixture is transferred to a high-pressure kettle lined with Teflon, heated at 80°C for 24 hours first; then the temperature is raised to 160°C, and rotated at a speed of 60 rpm for 24 hours; after the high-pressure kettle is cooled to room temperature, the separated solid product is filtered and washed with deionized water until the washing liquid is neutral, and the washed solid product is dried at room temperature overnight to obtain nanocrystalline sodium mordenite; (2) Sodium hydroxide, fumed silica and deionized water are mixed to obtain a sodium silicate solution, and the mass percentage of the three in the mixture is 5-20%, 15-30% and 50-70% respectively; metakaolin, NaOH and deionized water are mixed with nanocrystalline sodium mordenite to obtain a slurry; the mass percentage of the four in the mixture is 40-60%, 10-20%, 5-15% and 15-25% respectively; the uniformly mixed slurry is cast into a silicon mold and cured at 80°C in a closed environment for 24 hours; then demolded and cured at 80°C for another 24 hours to prepare the CO2 adsorbent.

5. A composite adsorbent of regular structure for hydrogen-rich tail gas according to claim 1, characterized in that, The preparation method of the Cu(I) / 4A molecular sieve adsorbent is: copper nitrate 0.2-0.5g, tetramethylammonium hydroxide 30-60g, aluminum hydroxide 0.5-5g, aluminum chloride 2-8g, tetraethyl orthosilicate 2-6g and deionized water 10-50g are mixed, and then crystallization reaction and reduction reaction are carried out in sequence to prepare Cu(I) / 4A molecular sieve; the crystallization reaction temperature is 90-120°C, and the reaction time is 180-220min; the reduction reaction conditions are: adding 0.2g of chromium chloride at 180-230°C for 200min.

6. A process for the preparation of a structured composite adsorbent for hydrogen-rich tail gas according to any one of claims 1 to 5, characterized in that, The preparation method of the dehydrating bed comprises the following steps: adding the active alumina and aramid fibers in claim 1 into polyurethane emulsion with a mass fraction of 40%, then adding water, 1 L of water corresponding to 1000 g of the mixture, and then dispersing the mixture by a dispersing machine to form a uniform mixed slurry; placing the slurry in a vacuum pug mill for aging for 20 h, then placing the slurry into a hydraulic extrusion molding machine for extrusion at a pressure of 16 MPa, drying the extruded sample at 100 DEG C for 6 h, and then obtaining the dehydrating bed after vacuum activation at 140 DEG C for 4 h; The preparation method of the dehydrating bed comprises the following steps: adding the active alumina and aramid fibers in claim 1 into polyurethane emulsion with a mass fraction of 40%, then adding water, 1 L of water corresponding to 1000 g of the mixture, and then dispersing the mixture by a dispersing machine to form a uniform mixed slurry; placing the slurry in a vacuum pug mill for aging for 20 h, then placing the slurry into a hydraulic extrusion molding machine for extrusion at a pressure of 16 MPa, drying the extruded sample at 100 DEG C for 6 h, and then obtaining the dehydrating bed after vacuum activation at 140 DEG C for 4 h;

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