CN-121988282-A - Molecular sieve adsorbent, and forming method and application thereof

Abstract

The invention discloses a molecular sieve adsorbent which comprises a hierarchical pore hard core and a molecular sieve shell, wherein the hierarchical pore hard core is an inorganic porous ball core with a mesoporous-macroporous composite structure, and the molecular sieve shell is a mixture of molecular sieve raw powder and a crosslinking agent. The invention also discloses a forming method of the molecular sieve adsorbent and application of the adsorbent in a pressure swing adsorption process.

Inventors

• FAN XIAOBIN
• QIN LIHONG
• ZHANG QICHENG
• CEN MINGJUN

Assignees

• 天津大学

Dates

Publication Date

20260508

Application Date

20260402

Claims (10)

1. 1. A molecular sieve adsorbent is characterized by comprising a hierarchical pore hard core and a molecular sieve shell, wherein the hierarchical pore hard core is an inorganic porous spherical core with a mesoporous-macroporous composite structure, and the molecular sieve shell is a mixture of molecular sieve raw powder and a crosslinking agent.
2. 2. The molecular sieve adsorbent of claim 1, wherein the hierarchical pore hard core has a particle diameter of 0.05mm to 1mm and the molecular sieve shell has a thickness of 1.5mm to 6mm.
3. 3. The molecular sieve adsorbent of claim 1, wherein the average pore size of the mesopores in the multistage pore hard core is 5nm to 35nm, the average pore size of the macropores is 80nm to 1 μm, and the ratio of the number of mesopores to the number of macropores is (5 to 95) to (95 to 5).
4. 4. The molecular sieve adsorbent according to claim 1, wherein the hardness of the hierarchical pore hard core is not less than 5N/particle, and the material of the hierarchical pore hard core is one or more of alumina, silica, titania, zirconia, silica-alumina composite, titanium-alumina composite, or zirconium-alumina composite.
5. 5. The molecular sieve adsorbent of claim 1, wherein the molecular sieve raw powder is a zeolite molecular sieve selectively adsorbing one or more gases selected from CO, CO 2 、CH 4 、N 2 、O 2 、O 3 、HCl、H 2 S, and VOCs, the chemical composition of the colloidal binder corresponds to at least one of the framework elements of the molecular sieve raw powder, and the colloidal binder is one or more of silica sol, sodium silicate solution, alumina sol, titanium sol, and zirconium sol.
6. 6. The molecular sieve adsorbent of claim 1, wherein the mass ratio of the molecular sieve raw powder to the colloidal linking agent is 100: (5-30).
7. 7. A method of forming a molecular sieve adsorbent according to any one of claims 1 to 6, comprising the steps of: (1) Weighing molecular sieve raw powder and a crosslinking agent according to a proportion; (2) Spraying adhesive agent on the surface of the hierarchical pore hard core, and then uniformly spraying mixed aqueous solution of molecular sieve raw powder and adhesive agent under the rolling state of the hierarchical pore hard core, so that the molecular sieve raw powder is continuously adhered on the surface of the hierarchical pore hard core to reach the required particle size; (3) And (3) drying and activating the wet blank obtained in the step (2) at high temperature to obtain the molecular sieve adsorbent.
8. 8. The molding method as claimed in claim 7, wherein the spraying speed in the step (2) is 0.5-2 mL/min and the rolling speed is 50-200 rpm.
9. 9. The molding method as claimed in claim 7, wherein the drying temperature in the step (3) is 80 to 150 ℃, the high-temperature activation temperature is 400 to 600 ℃ and the time is 2 to 6 hours.
10. 10. Use of the molecular sieve adsorbent according to any of claims 1-6 as an adsorbent in a pressure swing adsorption process.

Description

Molecular sieve adsorbent, and forming method and application thereof Technical Field The invention relates to the field of adsorption separation, in particular to a molecular sieve adsorbent, a forming method thereof and application of the molecular sieve adsorbent in quick balance of a pressure swing adsorption process. Background Gas separation is an indispensable key technology in the modern industry, and is widely applied to the fields of resource recovery (such as CO 2 trapping), air purification (such as VOCs removal), gas purification (oxygen production, nitrogen production and hydrogen production) and the like. The efficient gas separation technology is a core technology for improving the utilization rate of resources. At present, the pressure swing adsorption technology is one of mainstream gas separation technologies, and has the advantages of high target gas separation selectivity, high process operation flexibility, low energy consumption, less three wastes in the process and the like. However, this technique also has the inherent disadvantages of long adsorption equilibration times and long pressure swing cycle times, which severely limit the throughput and efficiency of the device. Therefore, the development of a highly selective adsorbent capable of achieving a rapid adsorption-desorption equilibrium is a key to promoting the progress of pressure swing adsorption technology. Zeolite molecular sieves are ideal high selectivity adsorption materials because of their regular microporous channels and extremely high specific surface area. However, the application of the method faces a core contradiction that the mass transfer speed of molecules in the particles is slow due to the limited narrow micropore diffusion rate, so that the adsorption-desorption equilibrium time is overlong. In order to put the molecular sieve in powder form into industrial use, it must be shaped. Conventional shaping techniques (e.g., extrusion and tabletting) generally require the introduction of a large amount (up to 30-40 wt%) of clay binders (e.g., kaolin, bentonite) that form amorphous phases after calcination, which not only block the molecular sieve channels and cover the active sites, resulting in significant reduction of adsorption capacity, but also further exacerbate the diffusion resistance of gas molecules and deteriorate the otherwise unfavorable kinetic properties. In order to solve the problems, the design concept of the core-shell structure adsorbent is proposed, however, the prior core-shell structure schemes have obvious limitations and cannot be effectively applied to pressure swing adsorption scenes, the patent CN2023110380754 adopts inert microspheres with no holes and high specific heat capacity as an inner core, the main purpose of the patent CN2023110380754 is to buffer adsorption heat, although the temperature fluctuation can be slightly improved, the problem of diffusion limitation of the core is completely helpless, and even the effective adsorption volume is reduced because the inner space of particles is occupied, the patent CN2022100456127 and the patent CN2022100455938 adopt inactive common binders or organic polymers to construct a shell layer, the adsorption capacity is diluted, the prior art cannot tolerate the frequent high-temperature regeneration process in the pressure swing adsorption process and is easy to decompose and fail, and the patent CN2025105307809 in the field of liquid phase adsorption, proposes a multiple structure comprising an inorganic composite shell layer and an intelligent response organic film, but the huge mass transfer resistance and thermal instability are not applicable to the gas phase pressure swing adsorption process pursuing high-speed gas diffusion and high-temperature stability. In view of the foregoing, there is a strong need in the art for a novel molecular sieve adsorbent that can maintain the intrinsic high adsorption capacity and selectivity of the molecular sieve, and also can achieve rapid adsorption-desorption kinetics, while having excellent mechanical strength and thermal stability, so as to truly meet the severe requirements of efficient pressure swing adsorption processes. The invention is proposed for this purpose. Disclosure of Invention The invention discloses a molecular sieve adsorbent, a forming method and application of a rapid equilibrium adsorbent in a pressure swing adsorption process. The technical scheme of the invention is as follows: The invention discloses a molecular sieve adsorbent, which comprises a hierarchical porous hard core and a selective adsorption type molecular sieve shell, wherein the hierarchical porous hard core is an inorganic porous spherical core with a mesoporous-macroporous composite structure, and the selective adsorption type molecular sieve shell is a mixture of molecular sieve raw powder and a colloid agent. Preferably, the particle diameter of the multistage pore hard core is 0.05mm-1mm, and the thickne