A low-temperature regenerative drying adsorbent and its preparation and regeneration method

Abstract

A low-temperature regenerative dry adsorbent and its preparation and regeneration method belong to the technical field of compressed air purification and adsorption materials. It is composed of the following components by weight: 80-92 parts of a modified zeolite matrix, 3-6 parts of carbon nanotubes, and 10 parts of a silica sol adhesive; the carbon nanotubes are adhered to the surface of the modified zeolite matrix by the silica sol adhesive. The adsorbent of the present invention significantly reduces desorption energy consumption through surface hydrophobic modification, and can achieve efficient regeneration under low temperature conditions; the carbon nanotube reinforced skeleton and the special adhesive work synergistically to greatly improve the mechanical strength and resistance to working condition impact; the in-situ growth technology ensures long-term stable loading of the functional components, and the performance attenuation rate after hydrothermal cycling is much lower than that of traditional adsorbents. The overall advantages are low-temperature energy saving, high stability and long life.

Description

Technical Field

[0001] The invention belongs to the technical field of compressed air purification and adsorption materials, and specifically relates to a low-temperature regeneration type dry adsorbent and a preparation and regeneration method thereof. Background Art

[0002] Compressed air drying technology is increasingly widely used in the industrial sector, but high-temperature energy consumption during adsorbent regeneration remains a bottleneck. Traditional adsorbents (such as 13X zeolite or silica gel) typically require a high-temperature heat source of 120°C to 180°C for regeneration, resulting in a consumption of 35% to 40% of the system's total energy consumption. Furthermore, due to limitations in low-temperature regeneration, mechanical stability, and preparation processes, existing technologies struggle to meet the demands for high energy efficiency and long-term stable operation.

[0003] Chinese patent CN115999333B discloses a compressed air dryer and its adsorbent regeneration method. This patent significantly reduces regeneration energy consumption and improves adsorbent regeneration efficiency by combining a compression heat regeneration mode with a blast heat regeneration mode. However, this technical solution still has the following shortcomings: First, its regeneration process relies on a high-temperature heat source (over 120°C), failing to achieve low-temperature regeneration, resulting in still high energy consumption; second, the hydrophobic modified layer of its adsorbent lacks thermal stability after multiple cycles of use, with the contact angle decaying from an initial 130° to below 90°, affecting its desorption performance during long-term use; finally, this solution does not involve optimizing the mechanical strength of the adsorbent, resulting in high breakage rates and reduced specific surface area under high-pressure conditions, limiting its application in precision manufacturing scenarios.

[0004] Another Chinese patent, CN110538550B, discloses a method and apparatus for the cyclic regeneration of adsorbents used in power plant compressed air drying. This patent achieves rapid desorption through microwave heating and completes adsorbent regeneration by purging with finished gas, significantly improving regeneration efficiency. However, this technical solution also has the following issues: First, while microwave heating can shorten regeneration time, it carries high equipment costs and requires high thermal conductivity for the adsorbent, limiting its applicability. Second, the adsorbent's loaded active components (such as MOFs) experience a high shedding rate during the extrusion process, causing fluctuations in dynamic adsorption performance and compressed air dew point fluctuations from -30°C to -25°C, making it difficult to meet stringent operating conditions. Finally, this solution fails to address the adsorbent's surface area degradation under long-term hydrothermal aging conditions. Testing according to GB / T 35109-2017 shows a surface area degradation of over 20%, and insufficient mechanical stability further limits its industrial application prospects.

[0005] The above problems indicate that the existing compressed air drying adsorbent and its regeneration technology still have obvious deficiencies in low-temperature regeneration capability, mechanical stability, production cost and long-term performance. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a low-temperature regenerative compressed air drying high-efficiency adsorbent having low-temperature regeneration performance, high mechanical strength and long-term stability and a preparation method thereof.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a low-temperature regeneration type drying adsorbent, characterized in that it is composed of the following components by weight: 80-92 parts of a modified zeolite matrix, 3-6 parts of carbon nanotubes, and 10 parts of a silica sol adhesive; the carbon nanotubes are adhered to the surface of the modified zeolite matrix by the silica sol adhesive.

[0008] The adsorbent of this invention significantly reduces desorption energy consumption through surface hydrophobic modification, enabling efficient regeneration even at low temperatures. The carbon nanotube-reinforced skeleton and specialized adhesives synergistically enhance mechanical strength and resistance to operating shocks. In-situ growth technology ensures long-term stable loading of functional components, and the performance degradation rate after hydrothermal cycling is far lower than that of traditional adsorbents. Overall, it combines the advantages of low-temperature energy conservation, high stability, and a long lifespan.

[0009] Specifically, the modified zeolite matrix is ​​a 13X zeolite with heptadecafluorodecyltrimethoxysilane grafted on the surface and loaded with ionic liquid [BMIM]PF6, and the inner wall of the pore of the 13X zeolite is also grown with a metal organic framework functional component, and the metal organic framework functional component is doped with 0.45wt% to 0.55wt% of Ce in the 13X zeolite. 3+ , the MOFs loading was 8±0.5wt% of 13X zeolite.

[0010] The modified zeolite matrix forms a super-hydrophobic surface by grafting heptafluorodecyltrimethoxysilane, and combined with the charge regulation effect of the ionic liquid [BMIM]PF6, it reduces the activation energy of water molecule desorption and significantly reduces the regeneration temperature threshold; Ce in situ grown on the inner wall of the pore 3+ Doping MOFs functional layer, using Ce 3+ The electronic regulation effect on the metal nodes weakens the polar interaction between water molecules and the skeleton, increasing the desorption rate at 90°C to more than 94%. 3+ Doping inhibits the structural collapse of the MOFs skeleton during hydrothermal cycles. After thousands of regenerations, the specific surface area attenuation rate is extremely small, which greatly improves the dew point stability of the adsorbent in long-term cycles.

[0011] The adsorbent particles have a diameter of 2.0±0.1 mm, a compressive strength of ≥50 N / particle, and a desorption rate of ≥94% at 90° C.

[0012] A method for preparing the above-mentioned low-temperature regeneration type drying adsorbent comprises the following steps:

[0013] (1) A 13X zeolite with a particle size of 1.5 mm to 2.0 mm was placed in a pressure-resistant reactor, and an ethanol solution of heptadecafluorodecyltrimethoxysilane with a concentration of 4.5 wt% to 5.5 wt% was injected. The reaction was carried out at 0.4 MPa to 0.6 MPa and 78°C to 82°C for 87 min to 93 min to obtain a grafted zeolite. The pressure was then reduced to normal pressure and the grafted zeolite was immersed in the ionic liquid [BMIM]PF6. The fluorinated modified zeolite was obtained by centrifugal dehydration and drying.

[0014] (2) adding a proportion of CeCl3 to a [BMIM]PF6 ionic liquid containing 0.08 mol / L to 0.12 mol / L CrCl3 to obtain an impregnation solution, adding the fluorinated modified zeolite to the impregnation solution and reacting under hydrothermal conditions at 147°C to 153°C for 5.5 h to 6.5 h to obtain the modified zeolite;

[0015] (3) The modified zeolite, carbon nanotubes and silica sol binder were mixed according to a ratio, melt-extruded at 180±5°C through a twin-screw extruder, and cut into particles with a diameter of 2.0±0.1 mm.

[0016] This preparation method achieves efficient preparation of high-performance adsorbents through a three-step innovative process: first, a one-step method is used to simultaneously complete the zeolite fluorosilane grafting and ionic liquid loading in a pressure-resistant reactor, avoiding the intermediate separation process and shortening the production cycle; second, Ce is synthesized in situ in the zeolite pores through the ionic liquid medium. 3+ Doping MOFs to realize Ce by utilizing the dual functions of [BMIM]PF6 3+ Coordination with Ce 3+ Electronic control synchronizes the MOF loading and ensures uniform distribution. Finally, a carbon nanotube-enhanced blend system, combined with 180°C melt extrusion and precise diameter control, ensures a particle compressive strength of ≥50N and significantly reduces breakage. This entire process streamlines the process while ensuring adsorbent desorption efficiency and reducing energy consumption.

[0017] Preferably, the impregnation of ionic liquid [BMIM]PF6 in step (1) of the above preparation method is specifically to mix the grafted zeolite with 13wt%~17wt% of ionic liquid [BMIM]PF6 of 13X zeolite, and impregnate it at a constant temperature of 55℃~65℃ for 100min~150min. By precisely controlling the ionic liquid loading amount and constant temperature conditions, [BMIM]PF6 can be uniformly infiltrated into the mesoporous channels of the zeolite: on the one hand, a charge control network is formed on the surface of the fluorosilane hydrophobic layer, further reducing the desorption activation energy; on the other hand, as a medium carrier for the in-situ synthesis of MOFs, it ensures the subsequent Cr 3+ / Ce 3+The efficient transport and coordination of ions within the pores increases the density of MOF crystal growth. The optimized impregnation time avoids localized aggregation of the ionic liquid, ensuring uniform distribution of the functional components. Ultimately, this significantly reduces the fluctuation range of the desorption rate at 90°C and significantly improves product batch stability.

[0018] Preferably, the drying in step (1) of the above preparation method is performed by vacuum drying and curing at 115°C to 125°C for 150 min to 200 min. This drying process precisely cures the ionic liquid coating, eliminates internal stress, ensures structural integrity, and lays the foundation for subsequent stable loading of MOFs.

[0019] Preferably, the silica sol binder in step (3) of the above preparation method has a mass solid content of 40% to 45%. This solid content precisely matches the requirements of the extrusion process: the high solid content ensures that the binder fully wraps the carbon nanotubes to form a three-dimensional reinforced network, thereby improving the compressive strength; the low viscosity ensures the melt's fluidity at 180°C, and the diameter control accuracy reaches ±0.1mm, ensuring the qualified rate of particles.

[0020] Preferably, the carbon nanotubes described in step (3) of the above preparation method are multi-walled carbon nanotubes, with a length ranging from 10 μm to 50 μm and an outer diameter of 8 nm to 15 nm. Multi-walled carbon nanotubes of specific size form a three-dimensional reinforced network in the binder: the optimized aspect ratio improves compressive strength, and the ultra-fine outer diameter avoids clogging the MOFs pores, synergistically improving adsorption kinetic stability and regenerative heat conduction efficiency.

[0021] Preferably, step (3) of the above preparation method further includes post-molding treatment: placing the extruded particles in a microwave reactor, irradiating them at a power of 800±40W for 90±5s, and controlling the particle surface temperature to be ≤110°C. This microwave post-treatment induces the directional condensation of the adhesive silanol groups to form a dense cross-linked network through precise radiation, further improving the compressive strength; controlling the surface temperature to be ≤110°C avoids thermal decomposition of the MOFs skeleton and ensures that Ce 3+ The stability of the doping structure ensures that the load retention rate is >98% after two thousand cycles.

[0022] A low-temperature regeneration method for the above-mentioned dry adsorbent comprises the following steps:

[0023] (a) Place the saturated adsorbent after adsorption in a regeneration tower and introduce compressed air at 60°C to 80°C for 8 to 12 minutes;

[0024] (b) Switch to normal pressure regeneration gas flow and apply 0.5 Hz to 1.0 Hz pulse pressure fluctuation at 75°C to 85°C for 15 min to 20 min;

[0025] (c) Dry air at 25°C to 35°C is introduced, the pressure is maintained at 0.7±0.05MPa, and the temperature is cooled to below 40°C to complete regeneration.

[0026] This regeneration method achieves efficient and energy-saving regeneration through a three-step synergistic approach: First, pre-desorption is performed using compressed air at 60-80°C, fully recovering waste heat from the air compressor and reducing external energy consumption. Subsequently, 0.5-1.0Hz pulse pressure fluctuations are applied at 75-85°C. This periodic pressure change disrupts the capillary condensation of water molecules, improving the desorption efficiency of bound water and completing deep regeneration in just 15-20 minutes. Finally, precise temperature control is applied using 0.7MPa constant pressure cold dry air to cool the adsorbent, preventing microcracks caused by rapid cooling and shrinkage, thereby ensuring structural integrity. The entire process is carried out at a low temperature of ≤85°C, which is more than 40°C lower than traditional regeneration temperatures. The regeneration cycle is shortened to less than 35 minutes, significantly reducing energy consumption, while maintaining adsorption capacity after long-term circulation and improving dew point stability.

[0027] Preferably, the compressed air velocity in step (a) of the low-temperature regeneration method is 0.8 m / s to 1.2 m / s; and the pulse pressure fluctuation amplitude ΔP in step (b) is 0.3 MPa to 0.5 MPa. The 0.8-1.2 m / s air velocity precisely matches the compression heat transfer efficiency, shortening the pre-desorption time. The 0.3-0.5 MPa pulse amplitude thoroughly disrupts the hydrogen bond network of water molecules through cavitation, significantly improving the bound water removal rate at 85°C while simultaneously reducing pulse energy consumption and overall energy efficiency.

[0028] Compared with the prior art, the low-temperature regenerative drying adsorbent and its preparation and regeneration method of the present invention have the following beneficial effects: the present invention systematically breaks through the technical bottleneck in the field of compressed air drying through the collaborative innovation of material system and process. The adsorbent adopts a triple functional modification design: super-hydrophobic surface modification significantly reduces the adsorption energy barrier of water molecules, ionic liquid loading optimizes the charge distribution, and the functional components with stable loads in the pores precisely regulate hydration to achieve low-temperature and efficient regeneration; the preparation process pioneers synchronous modification technology to shorten the process, ion thermal in-situ synthesis ensures uniform distribution of functional components, and enhanced materials and microwave post-treatment synergistically improve mechanical durability; the regeneration method innovatively integrates waste heat recovery, pulse pressure change desorption and precise temperature control technology to greatly reduce regeneration temperature and energy consumption. The overall technology enables the adsorbent to have excellent low-temperature regeneration, mechanical stability and long life characteristics, the dew point control accuracy reaches the top industrial standard, and the comprehensive operation and maintenance costs are significantly reduced, providing energy-saving and reliable drying solutions for the high-end manufacturing industry. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to specific embodiments, wherein embodiment 1 is the best embodiment. Example 1

[0030] 1. Adsorbent preparation process

[0031] (1) A 13X zeolite raw material with a particle size of 1.8 mm was placed in a pressure-resistant reactor and injected with an ethanol solution containing 5 wt% heptafluorodecyltrimethoxysilane. The reaction was carried out at 0.5 MPa and 80°C for 90 minutes to complete the fluorosilane grafting. While maintaining the reaction system without separation, an ionic liquid [BMIM]PF6 equivalent to 15 wt% of the zeolite mass was directly added. After reducing the pressure to normal pressure, the mixture was immersed at a constant temperature of 60°C for 120 minutes. Nitrogen was introduced throughout the reaction. The obtained product was centrifuged and dehydrated, and then dried and solidified in a vacuum oven at 120°C for 180 minutes to obtain a fluorinated modified zeolite matrix.

[0032] (2) The modified zeolite was immersed in a pre-prepared impregnation solution ([BMIM]PF6 ionic liquid containing 0.1 mol / L CrCl3 and 0.5 wt% CeCl3), placed in a high-pressure reactor, and reacted under hydrothermal conditions at 150 ° C for 6 hours to make Ce 3+ The doped MIL-101(Cr) framework was directionally grown on the inner wall of the zeolite pores. After the reaction, the functionalized modified zeolite was obtained by washing with deionized water and drying in vacuum at 80°C.

[0033] (3) 85 parts of functionalized modified zeolite, 5 parts of multi-walled carbon nanotubes (length 30 μm, outer diameter 10 nm) and 10 parts of silica sol adhesive with a solid content of 42% were mixed evenly, melt-extruded through a twin-screw extruder at a mold temperature of 180 °C, and cut into cylindrical particles with a diameter of 2.00 ± 0.05 mm.

[0034] (4) Finally, the particles were placed in a microwave reactor and irradiated at 800 W for 90 seconds (surface temperature was monitored in real time to be ≤110°C) to complete the strengthening treatment.

[0035] 2. Implementation of regeneration method

[0036] The saturated adsorbent was placed in a regeneration tower and introduced with 70°C compressed air at a controlled velocity of 1.0 m / s for 10 minutes to achieve initial desorption. The regeneration tower then switched to atmospheric pressure, applying pulsed pressure fluctuations of 0.4 MPa at 0.75 Hz at 80°C for 18 minutes. Finally, 30°C dry air was introduced, maintaining the system pressure at 0.7 MPa, and the system was cooled to below 35°C to complete regeneration.

[0037] 3. Performance Test Results

[0038] Low-temperature desorption performance: The 90°C constant-temperature desorption test (ISO 12500 standard) showed a desorption rate of 96.2%.

[0039] Mechanical strength: Particle compressive strength is 63N (GB / T 10531-2022 test), and the breakage rate is less than 0.5% after 5000 pressure cycles (0~1.0MPa).

[0040] Adsorption stability: The dynamic adsorption capacity is 0.34gH2O / g adsorbent (inlet conditions 40℃ / RH80%), and the dew point is stable at -52℃±0.8℃.

[0041] Lifespan performance: After 5,000 thermal shock cycles between -40°C and 90°C, the specific surface area decayed by only 3.7%, and the MOFs loading retention rate was >98%.

[0042] Energy consumption index: Regeneration energy consumption 0.14kWh / kg·H2O. Example 2

[0043] 1. Adsorbent preparation process

[0044] (1) A 13X zeolite with a particle size of 1.5 mm was placed in a pressure-resistant reactor. An ethanol solution containing 4.5 wt% heptafluorodecyltrimethoxysilane was injected and the reaction was carried out at 0.4 MPa and 78°C for 87 minutes. After the reaction was completed, an ionic liquid [BMIM]PF6 equivalent to 13 wt% of the zeolite mass was directly added. The pressure was reduced to normal pressure and the mixture was kept at 55°C for 100 minutes. Nitrogen was used throughout the process. The product was centrifuged and dehydrated, and then dried and solidified in a vacuum oven at 115°C for 150 minutes.

[0045] (2) The fluorinated modified zeolite was immersed in a [BMIM]PF6 solution containing 0.08 mol / L CrCl3 and 0.45 wt% CeCl3, placed in an autoclave, and reacted hydrothermally at 147°C for 5.5 hours. After the reaction, the zeolite was washed with deionized water and dried in vacuo at 80°C to obtain the modified zeolite.

[0046] (3) 80 parts of modified zeolite, 3 parts of multi-walled carbon nanotubes (length 10 μm, outer diameter 8 nm) and 10 parts of silica sol adhesive with a solid content of 40% were mixed evenly, melt-extruded through a twin-screw extruder at a mold temperature of 180 °C, and cut into cylindrical particles with a diameter of 2.0 ± 0.1 mm.

[0047] (4) The extruded particles were placed in a microwave reactor and irradiated at a power of 760 W for 85 seconds (surface temperature ≤ 105 °C).

[0048] 2. The low temperature regeneration method is the same as in Example 1.

[0049] 3. Performance test results: Desorption rate: 92.5%; Compressive strength: 51N / particle; Dew point stability: -49℃±2.5℃; MOFs loading: 7.8wt%. Example 3

[0050] 1. Adsorbent preparation process

[0051] (1) A 13X zeolite with a particle size of 2.0 mm was placed in a pressure-resistant reactor. An ethanol solution containing 5.5 wt% heptafluorodecyltrimethoxysilane was injected and the reaction was carried out at 0.6 MPa and 82°C for 93 minutes. After the reaction was completed, an ionic liquid [BMIM]PF6 equivalent to 17 wt% of the zeolite mass was directly added. The pressure was reduced to normal pressure and the mixture was kept at a constant temperature of 65°C for 150 minutes. Nitrogen was used throughout the process. The product was centrifuged and dehydrated, and then dried and solidified in a vacuum oven at 125°C for 200 minutes.

[0052] (2) The fluorinated zeolite was immersed in a [BMIM]PF6 solution containing 0.12 mol / L CrCl3 and 0.55 wt% CeCl3, placed in an autoclave, and reacted hydrothermally at 153°C for 6.5 hours. After the reaction, the zeolite was washed with 0.05 M HNO3 solution, rinsed with deionized water until neutral, and dried in a vacuum oven at 80°C.

[0053] (3) 92 parts of modified zeolite, 6 parts of multi-walled carbon nanotubes (length 50 μm, outer diameter 15 nm) and 10 parts of silica sol adhesive with a solid content of 45% were mixed, melt-extruded through a twin-screw extruder at a mold temperature of 185 °C, and cut into cylindrical particles with a diameter of 2.0 ± 0.1 mm.

[0054] (4) The extruded particles were placed in a microwave reactor and irradiated at a power of 840 W for 95 seconds (surface temperature was monitored in real time and was ≤108°C).

[0055] 2. Low temperature regeneration method

[0056] The saturated adsorbent was placed in a regeneration tower and introduced with 80°C compressed air at a controlled velocity of 1.2 m / s for 8 minutes to achieve initial desorption. The regeneration tower then switched to atmospheric pressure, applying pulsed pressure fluctuations of 0.5 MPa at 1.0 Hz at 85°C for 15 minutes. Finally, 35°C dry air was introduced, maintaining the system pressure at 0.75 MPa, and the system was cooled to below 38°C to complete regeneration.

[0057] 3. Performance test results: Desorption rate: 94.1%; Compressive strength: 59N / particle; MOFs loading: 8.4wt%; Dew point stability: -50℃±1.8℃. Example 4

[0058] The basic process is the same as that of Example 1, except that the particle size of the 13X zeolite raw material used in step (1) is 1.5 mm.

[0059] Performance test results: desorption rate: 95.1%; compressive strength: 58N / particle; MOFs loading: 8.0wt%; dew point stability: -51℃±1.2℃; cycle life: specific surface area decays by 4.3% after 5000 thermal shocks. Example 5

[0060] 1. Adsorbent preparation process

[0061] Steps (1) to (3) are exactly the same as those in Example 1, except that the post-treatment in step (4) is changed: the microwave treatment is canceled and replaced with: the extruded particles are placed in a hot air drying oven and treated at 120°C for 2 hours.

[0062] 2. Regeneration method

[0063] Exactly the same as Example 1.

[0064] 3. Performance test results: Compressive strength: 41N / particle; dew point stability: -45℃±5.0℃; cycle breakage rate: 18% (500 times); MOFs retention rate: 72% (500 times). Example 6

[0065] 1. Adsorbent preparation process

[0066] Completely consistent with Example 1.

[0067] 2. Low temperature regeneration method

[0068] (a) Introduce compressed air at 60°C with a controlled airflow velocity of 0.8 m / s for 12 minutes.

[0069] (b) Pulse pressure with a fluctuation amplitude of 0.3 MPa and a frequency of 0.5 Hz was applied at 75 °C for 20 min.

[0070] (c) Introduce dry air at 25°C, maintain the system pressure at 0.65 MPa, and cool to below 35°C.

[0071] 3. Performance Test Results

[0072] Desorption rate: 94.8% (ISO 12500:2007 test); Regeneration energy consumption: 0.16 kWh / kg·H2O; Dew point stability: -50°C ± 1.2°C; Particle breakage rate: only 0.8% after 5000 pressure cycles (0-1.0 MPa); MOF retention rate: 96.3%.

[0073] Comparative Example 1

[0074] The basic process is the same as that of Example 1, except that CeCl3 is not added in step (2).

[0075] Performance comparison: Desorption rate: 83.6% (down 12.6% compared to Example 1); Cycle attenuation: Specific surface area decreased by 38% after 500 cycles (BET test); This is because Ce 3+ Deletion leads to Cr 3+ Nodes are not resistant to hydrolysis.

[0076] Comparative Example 2

[0077] The basic process is the same as that of Example 1, except that zeolite with a particle size of 3.0 mm is used.

[0078] Performance comparison: Compressive strength: 68N / particle; dew point stability: -42℃±8℃; The diffusion path within the 3.0mm particle is too long, resulting in incomplete regeneration.

[0079] Comparative Example 3

[0080] The basic process is the same as that of Example 1, except that in step (b), the pulse fluctuation is eliminated and replaced with a constant pressure purge at 85°C.

[0081] Performance comparison: Desorption rate: 81.3%; dew point fluctuation: -45℃±5.0℃ (SEM shows pore blockage by hydrated clusters); 30-day breakage rate reaches 22%, which is due to the accumulation of mechanical fatigue caused by the lack of pulses.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A low-temperature regenerative drying adsorbent, characterized in that: The invention is composed of the following components by weight: 80-92 parts of a modified zeolite matrix, 3-6 parts of carbon nanotubes, and 10 parts of a silica sol binder; the carbon nanotubes are adhered to the surface of the modified zeolite matrix by the silica sol binder; the modified zeolite matrix is ​​a 13X zeolite with heptadecafluorodecyltrimethoxysilane grafted on the surface and loaded with the ionic liquid [BMIM]PF6; a metal organic framework functional component is also grown on the inner wall of the pores of the 13X zeolite; the metal organic framework functional component is doped with 0.45wt%-0.55wt% of Ce in the 13X zeolite. 3+ , the MOFs loading amount is 8±0.5wt% of the 13X zeolite; the particle size of the 13X zeolite is 1.5mm~2.0mm.

2. A method for preparing the low-temperature regeneration type drying adsorbent according to claim 1, characterized in that: The following steps are involved: (1) A 13X zeolite with a particle size of 1.5 mm to 2.0 mm was placed in a pressure-resistant reactor, and an ethanol solution of heptadecafluorodecyltrimethoxysilane with a concentration of 4.5 wt% to 5.5 wt% was injected. The reaction was carried out at 0.4 MPa to 0.6 MPa and 78°C to 82°C for 87 min to 93 min to obtain a grafted zeolite. The pressure was then reduced to normal pressure and the grafted zeolite was immersed in the ionic liquid [BMIM]PF6. The fluorinated modified zeolite was obtained by centrifugal dehydration and drying. (2) adding a proportion of CeCl3 to a [BMIM]PF6 ionic liquid containing 0.08 mol / L~0.12 mol / L CrCl3 to obtain an impregnation solution, adding the fluorinated modified zeolite to the impregnation solution, and reacting under hydrothermal conditions of 147°C~153°C for 5.5h~6.5h to obtain the modified zeolite; (3) The modified zeolite, carbon nanotubes and silica sol binder were mixed according to a ratio, melt-extruded at 180±5°C through a twin-screw extruder, and cut into particles with a diameter of 2.0±0.1 mm.

3. The method for preparing a low-temperature regenerated dry adsorbent according to claim 2, characterized in that: The step (1) of impregnating the grafted zeolite in the ionic liquid [BMIM]PF6 is specifically to mix the grafted zeolite with 13 wt% to 17 wt% of the ionic liquid [BMIM]PF6 of 13X zeolite, and to impregnate the mixture at a constant temperature of 55°C to 65°C for 100 min to 150 min.

4. The method for preparing a low-temperature regenerated dry adsorbent according to claim 2, characterized in that: The drying in step (1) is performed by vacuum drying and curing at 115°C to 125°C for 150min to 200min.

5. The method for preparing a low-temperature regenerated dry adsorbent according to claim 2, characterized in that: The silica sol adhesive in step (3) has a mass solid content of 40% to 45%.

6. The method for preparing a low-temperature regenerated dry adsorbent according to claim 2, characterized in that: The carbon nanotubes described in step (3) are multi-walled carbon nanotubes with a length ranging from 10 μm to 50 μm and an outer diameter of 8 nm to 15 nm.

7. The method for preparing a low-temperature regeneration type drying adsorbent according to claim 2, characterized in that: Step (3) also includes post-molding treatment: placing the extruded particles in a microwave reactor, irradiating them at a power of 800±40W for 90±5s, and controlling the particle surface temperature to be ≤110°C.

8. A method for regenerating the low-temperature regeneration type drying adsorbent according to claim 1, characterized in that: The following steps are involved: (a) Place the saturated adsorbent after adsorption in a regeneration tower and introduce compressed air at 60°C to 80°C for 8 to 12 minutes; (b) Switch to normal pressure regeneration gas flow and apply 0.5 Hz to 1.0 Hz pulse pressure fluctuation at 75°C to 85°C for 15 min to 20 min; (c) Dry air at 25°C to 35°C is introduced, the pressure is maintained at 0.7±0.05MPa, and the temperature is cooled to below 40°C to complete regeneration.

9. The regeneration method of a low-temperature regeneration type drying adsorbent according to claim 8, characterized in that: The air flow velocity of the compressed air in step (a) is 0.8 m / s to 1.2 m / s; and the fluctuation amplitude ΔP of the pulse pressure fluctuation in step (b) is 0.3 MPa to 0.5 MPa.