A method for gas enrichment and separation control of a porous adsorbent material

Abstract

The application discloses a kind of gas enrichment and separation control method for porous adsorption material.Method includes:SO pretreatment activation, before first use, heat 100-130 DEG C and discharge material internal residual moisture and impurity;SO-1 air inlet pre-drying, the relative humidity of entering air is reduced to ≤40%, prevent water vapor competitive occupation adsorption site;S1 through active temperature control and lateral air distribution complete normal temperature adsorption;S2 in non-sealed state heating desorption, water vapor (18g / mol) is driven by thermal buoyancy and escapes through top open channel, high concentration target gas (44g / mol) is gathered along bottom slope under gravity, and the cavity maintains near constant pressure laminar flow state;S3 is output by frequency conversion drainage unit in slow release or long-distance directional transport mode.The application does not need sealing valve, and the adsorption efficiency is double guaranteed by pretreatment activation and air inlet pre-drying, and it is universal in full humidity environment, and the application scenarios are wide.

Description

Technical Field This invention belongs to the field of gas separation and capture technology, specifically relating to a gas enrichment and separation control method for porous adsorption materials, and in particular a carbon dioxide enrichment control method based on pretreatment activation, air intake pre-drying, and non-sealed gravity diversion. Background Technology Most existing gas enrichment equipment (especially carbon dioxide capture equipment) adopts a closed tank structure. This structure has the following fatal flaws in the heating desorption process: First, because the tank is sealed, a large number of water molecules captured inside the adsorption material during the adsorption process cannot be effectively discharged after evaporation due to heating. The water vapor mixes with high concentrations of carbon dioxide in the sealed cavity and condenses and flows back inside the material after the tank temperature drops, causing the adsorption material to become poisoned and ineffective. Second, traditional equipment must rely on solenoid valves or mechanical seals to completely seal the cavity during the heating phase to build up pressure, which not only increases the equipment failure rate but also significantly increases manufacturing costs. Third, traditional tank structures often use instantaneous valve opening to release gas, resulting in large fluctuations in output concentration. This makes it impossible to flexibly adjust the concentration and flow rate according to actual application scenarios (such as attracting mosquitoes at close range with high concentrations or supplementing carbon to plants at a distance). Fourth, traditional equipment does not consider the impact of high humidity on adsorption efficiency. Water vapor in the air preferentially occupies the active sites of the adsorption material, resulting in a significant decrease in the adsorption capacity of the target gas. Fifth, the adsorption materials used in traditional equipment have residual moisture and impurities from the preparation, transportation, and storage processes that are used directly without treatment, resulting in low adsorption efficiency. The carbon dioxide enrichment devices disclosed in Chinese invention patent CN117337814B and Chinese utility model patent CN212757915U (Tang Chengkang) use a closed tank with a baffle and a solenoid valve structure. During desorption, the valve needs to be closed to suppress the pressure, and water vapor cannot be discharged in time, which has all the above defects. There is no complete technical solution for the coordinated control of "air pre-drying + pretreatment activation + non-sealed gravity diversion + frequency conversion output" for porous adsorption materials in the existing technology. Summary of the Invention To address the aforementioned deficiencies in existing technologies, this invention provides a method for controlling gas enrichment and separation in porous adsorption materials. To achieve the above objectives, the present invention adopts the following technical solution: Step S0, Pretreatment and Activation Step: Before first use, the porous adsorption component is pretreated by heating at a temperature of 100-130℃ for 30-120 minutes to allow residual moisture and impurities inside the porous adsorption component to be discharged in gaseous form, thus completing the material activation. Step S0-1, Air Inlet Pre-drying Step: Before the outside air enters the lateral air distribution channel, it flows through the pre-drying module set in the air inlet channel to reduce the relative humidity of the air to below the preset threshold (≤40%). Step S1, Cooling and Adsorption Step: After the external air is adjusted to the preset adsorption temperature by the active temperature control device, it is introduced into the device through the side air distribution channel. The airflow passes through the porous adsorption component set inside the device to complete the adsorption and enrichment of the target gas. Step S2, Thermal Desorption and Gravity Diversion Step: Stop the air intake and heat the porous adsorption component for desorption; the water vapor generated by desorption moves upward under the drive of thermal buoyancy and is discharged outward through the atmospheric pressure adaptive evaporation channel at the top of the device; the high-concentration target gas generated by desorption settles and accumulates naturally downward along the continuous guide slope at the bottom of the device under the dominance of gravity; the atmospheric pressure adaptive evaporation channel is always connected to the outside atmosphere, and no mechanical seal valves are installed in the channel to block the airflow. Step S3, Variable Frequency Output and Scene Switching: Control the variable frequency diversion unit located at the bottom, and output the accumulated high-concentration target gas to the outside in a high-concentration slow release mode or a long-distance directional delivery mode by changing the operating parameters of the diversion unit. The adsorption mechanism of CO2 by the porous adsorbent material used in this invention is a synergistic effect of physical and chemical adsorption, with adsorption sites mainly distributed on the inner walls of micropores and mesopores. In ambient air, water vapor (H2O, molar mass 18 g / mol, kinetic diameter approximately 0.28 nm) and CO2 (molar mass 44 g / mol, kinetic diameter approximately 0.33 nm) coexist. Due to the stronger polarity and smaller kinetic diameter of water molecules, on the surface of the hydrophilic adsorbent material, water molecules are preferentially adsorbed and occupy active sites, forming a water molecule layer that hinders CO2 molecules from entering the pores. The pretreatment activation step involves heating the material to a temperature 10-30°C (preferably 100-130°C) above the conventional desorption temperature, using thermal energy to expel water molecules and impurity molecules from the microporous structure. After pretreatment activation, the material's adsorption capacity can be restored to more than 95% of the theoretical value. The air pre-drying step is performed before each adsorption cycle. Experimental data show that at a relative humidity of 60%, the CO2 adsorption capacity of this material decreases by approximately 35% compared to the dry condition; at a relative humidity of 80%, the adsorption capacity decreases by more than 50%. Controlling the relative humidity below 40% ensures that the adsorption sites are used to capture the target gas to the maximum extent, maintaining the adsorption capacity at more than 90% of its theoretical value. Compared to the traditional "valve-closed and air-holding" method, the core of this invention lies in the fact that no mechanical seal is required on the cavity during the desorption process. This invention utilizes the natural physical properties of water vapor (molar mass 18 g / mol, density less than air) rising under thermal buoyancy and the target gas (molar mass 44 g / mol, density greater than air) settling downward under gravity, achieving non-contact physical separation of gas and moisture, completely eliminating the dependence on sealing valves. The core physical basis for the effective separation of water vapor and target gas in this invention lies in the difference in their molar mass and the difference in their settling velocity under laminar flow conditions. According to Stokes' law of settling, in the same temperature field and flow field, the settling velocity of the target gas molecule cluster is about 2-3 times that of water vapor. This invention ensures the realization of laminar flow conditions through the following design: (1) The top channel is always open, there is no pressure buildup in the cavity, and the gas flow rate is always maintained in the low Reynolds number range (Re<2000); (2) The bottom guide slope angle is set to 15-30°, which ensures that the target gas slides smoothly without generating turbulence; (3) The heating elements adopt a distributed layout to avoid convection turbulence caused by local overheating. The beneficial effects of the present invention are as follows: (1) In contrast to the traditional "valve shut-off and air-holding" desorption process, the present invention completes the desorption in a state where the cavity is always connected to the outside world, completely eliminating the dependence on the electric sealing mechanism and significantly reducing the equipment failure rate; (2) Through the pretreatment activation step, the material is ensured to reach the best adsorption performance when used for the first time, and the adsorption capacity can be increased by 20-40%; (3) Through the air intake pre-drying step, the device can operate stably in a full humidity environment (relative humidity 20-90%); (4) Through frequency conversion output, high-concentration slow release or long-distance delivery can be achieved, adapting to a variety of application scenarios. Attached Figure Description Figure 1 This is a flowchart of the control method of the present invention.

[0001] Figure 2 This is a cross-sectional schematic diagram of the lateral air distribution and gravity settlement principle of the device of the present invention.

[0002] Figure 3 This is a schematic diagram of the top venting channel structure of the present invention.

[0003] Figure 4 This is a schematic diagram of the pre-drying module of the present invention.

[0004] The meanings of the labels in the figures are as follows: 1-Main shell; 2-Porous adsorption component; 3-Top atmospheric pressure adaptive dissipation channel; 4-Upper internal airflow cavity; 5-Lower internal airflow cavity; 6-Air inlet pre-drying module; 7-Internal side wall channel; 8-Umbrella-shaped waterproof cover; 9-Guiding air collection condensation funnel; 10-Variable frequency induced flow fan; 11-Removable base plate; 12-Baffle. Detailed Implementation The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. This invention does not limit the specific type of porous adsorbent material. Any porous material capable of adsorbing the target gas (especially carbon dioxide) and releasing it under heating conditions can be used in this invention. As an example and not a limitation, the porous adsorbent material can be selected from any one or more combinations of the following types: aluminum-based materials (including but not limited to aluminum-based compounds prepared by precipitation, hydrothermal or sol-gel methods using aluminum salts as precursors), carbon-based materials (including but not limited to activated carbon, carbon molecular sieves, carbon aerogels, carbon nanotubes and their composite modified carbon-based adsorbent materials), molecular sieve materials (including but not limited to ZSM-5, 13X, 4A, Y-type and other aluminosilicate molecular sieves and their ion exchange modifiers), metal-organic framework materials (including but not limited to MOF-5, MIL-101, ZIF-8 and other series MOF materials and their derivatives), porous polymer materials (including but not limited to covalent organic frameworks, hypercrosslinked polymers, porous aromatic frameworks, etc.), and composite adsorbent materials (composed of two or more of the above materials through physical mixing, chemical bonding or in-situ growth, etc.). Example 1: High-throughput plant carbon supplementation application In this embodiment, the porous adsorbent is selected as granular aluminum-based carbon dioxide capture material with a particle size of 1-10 mm and a specific surface area of ​​200-400 m² / g. The device is installed on the inner wall of a plant factory or greenhouse. Before first use, perform step S0 pretreatment activation: heat the porous adsorption component to 120°C for 60 minutes to allow residual moisture and impurities inside the material to escape in gaseous form through the top channel. After pretreatment activation, the material's adsorption capacity recovers to more than 95% of the theoretical value. Routine operation: Step S0-1, air pre-drying, involves external air (70% relative humidity) flowing through a solid desiccant bed (filled with molecular sieves) until the relative humidity drops below 35%, then entering the lateral air distribution channel. Step S1 activates the active temperature control device (semiconductor cooling chip), stabilizing the external air temperature at 20-25°C before introducing it into the main chamber. The airflow passes through a porous adsorption component composed of granular adsorption material, achieving a CO2 adsorption efficiency of over 95% of the room-temperature saturated adsorption. Adsorption time is 2-4 hours. Once the adsorption threshold is reached, step S2 is executed, the heating component is activated, and the temperature rises to 80-120℃. Because the atmospheric pressure adaptive escaping channel at the top of the chamber is completely connected to the outside atmosphere and has no sealing valves, the water vapor generated by heating (density less than air) directly escapes upwards. High-concentration CO2 gas (density greater than air) settles downwards along the continuous guide slope at the bottom (inclination angle 20°) under gravity and accumulates in the bottom settling chamber, reaching a concentration of 1500-3000 ppm. Step S3 is executed, the variable frequency drive unit operates intermittently at low speed (20-30% of rated speed) (on for 2 minutes, off for 1 minute), and the high-concentration CO2 at the bottom slowly diffuses into the plant cultivation area, ensuring that the CO2 concentration in the area is maintained in the 800-1200 ppm range for ≥90% of the time. Example 2: Long-distance mosquito attraction application In this embodiment, steps S0 (pretreatment activation) and S0-1 (air intake pre-drying) are the same as in Example 1. Steps S1 and S2 are the same as in Example 1. When performing step S3, the bottom variable frequency diversion unit starts and runs continuously at a medium-high speed (60-80% of the rated speed). The negative pressure generated by the fan draws the high concentration of CO2 (concentration ≥1500ppm) accumulated at the bottom into the pipeline and pushes it towards the distant target area (10-30 meters) in a directional airflow manner. The airflow is released in a pulse manner (pulse width 0.2-0.5 seconds, interval 1-3 seconds), simulating the human breathing rhythm, and working synergistically with the CO2 concentration gradient to significantly improve the mosquito trapping efficiency. Example 3: Air purification application in enclosed spaces In this embodiment, the device is installed on the inner wall of a closed space such as a conference room, classroom, or underground parking lot. After performing step S0-1, the air intake pre-drying, in step S1, the variable frequency air intake unit reverses at a low speed (air intake mode, 30-40% of rated speed) to draw in CO2-rich air from the space through the lateral air distribution channel. The air passes through the porous adsorption component to complete CO2 adsorption, and the purified air flows back into the space through the top channel. When adsorption reaches saturation, the system switches to step S2 (desorption mode), where the CO2 and water vapor generated by heating and desorption are discharged to the outside or the exhaust system through the top channel, and the adsorption material is regenerated. In step S3, the variable frequency air intake unit discharges the remaining CO2 to the outside in directional delivery mode (50-70% of rated speed). In this embodiment, adsorption and desorption are performed alternately to achieve continuous control of CO2 concentration in the closed space (target concentration ≤600ppm), eliminating the need for additional ventilation equipment and reducing air conditioning energy consumption by 30-40%. The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any equivalent modifications made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of the present invention.

Claims

1. A method for controlling gas enrichment and separation in porous adsorption materials, characterized in that, Includes the following steps: Step S0, Pretreatment and Activation Step: Before first use, the porous adsorption component is pretreated by heating at a temperature of 100-130℃ for 30-120 minutes to allow residual moisture and impurities inside the porous adsorption component to be discharged in gaseous form, thus activating the material. The water vapor and impurity gas generated during the pretreatment are discharged outward through the top atmospheric pressure adaptive evacuation channel. Step S0-1, Pre-drying step: Before the outside air enters the lateral air distribution channel, it flows through the pre-drying module set in the air inlet channel to reduce the relative humidity of the air to below the preset threshold, so as to reduce the competitive occupation of water vapor on the adsorption sites of the porous adsorption component. Step S1, Cooling and Adsorption Step: After the external air is adjusted to the preset adsorption temperature by the active temperature control device, it is introduced into the device through the side air distribution channel; the airflow passes through the porous adsorption component set inside the device to complete the adsorption and enrichment of the target gas. Step S2, Thermal Desorption and Gravity Diversion Step: Stop the air intake and heat the porous adsorption component for desorption; the water vapor generated by desorption moves upward under the drive of thermal buoyancy and is discharged outward through the atmospheric pressure adaptive evacuation channel at the top of the device; The high-concentration target gas generated by desorption naturally settles and accumulates downward along the continuous guide slope at the bottom of the device under the influence of gravity; the atmospheric pressure adaptive escaping channel is always connected to the outside atmosphere, and no mechanical seal valves are installed in the channel to block the airflow; the continuous guide slope is set at the bottom of the cavity, and a straight flow channel with no interception or throttling is formed between the top channel and the bottom settling cavity; Step S3, Variable Frequency Output and Scene Switching: Control the variable frequency diversion unit located at the bottom, and output the accumulated high-concentration target gas to the outside in a high-concentration slow release mode or a long-distance directional delivery mode by changing the operating parameters of the diversion unit.

2. The method for gas enrichment and separation control in porous adsorption materials according to claim 1, characterized in that: In step S0-1, the preset threshold is relative humidity ≤40%.

3. The method for gas enrichment and separation control in porous adsorption materials according to claim 1, characterized in that: In step S0-1, the pre-drying module is selected from any one or more combinations of solid desiccant bed, condenser dehumidifier, semiconductor refrigeration dehumidifier or membrane dehumidifier.

4. The method for gas enrichment and separation control in porous adsorption materials according to claim 3, characterized in that: The desiccant filling the solid desiccant bed is selected from at least one of silica gel, molecular sieve, and activated alumina; the desiccant is a replaceable or online regenerable structure.

5. The method for gas enrichment and separation control in porous adsorption materials according to claim 1, characterized in that: In step S2, the cavity is maintained at near-normal pressure during desorption, and the gas flow rate is in laminar flow. Water vapor (molar mass 18 g / mol) and target gas (molar mass 44 g / mol) are passively separated in situ based on the difference in molar mass. The inclination angle of the continuous guide slope is 15-30°.

6. The method for gas enrichment and separation control in porous adsorption materials according to claim 1, characterized in that: The active temperature control device is selected from any one of semiconductor refrigeration chips, compressor refrigeration systems, or water-cooled heat exchange coils.

7. The method for gas enrichment and separation control in porous adsorption materials according to claim 1, characterized in that: The porous adsorption component is selected from any one of the following: a physical stack of granular adsorption materials, a breathable mesh carrier coated with adsorption material, or an integrated porous plate formed by pressing or foaming.

8. The method for gas enrichment and separation control in porous adsorption materials according to claim 1, characterized in that: The target gas is carbon dioxide, and the adsorption material used in the porous adsorption component is selected from any one of aluminum-based materials, carbon-based materials, molecular sieves, and metal-organic framework materials.

9. The method for gas enrichment and separation control in porous adsorption materials according to claim 1, characterized in that: The high-concentration slow-release mode controls the variable frequency diversion unit to operate at low speed or intermittently to maintain the laminar flow state of the accumulated gas mass; the long-distance directional delivery mode controls the variable frequency diversion unit to operate continuously at medium to high speed to generate directional airflow for delivery.

10. The method for gas enrichment and separation control in porous adsorption materials according to claim 1, characterized in that: The method is applicable to at least one of the following scenarios: mosquito trapping, agricultural carbon-rich gas supply, or enclosed space air purification.

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