Composite adsorbents and feed compositions and methods of making, use in hydrogen isotope swing adsorption systems and control methods

Abstract

The application provides a composite adsorbent and raw material composition and a preparation method, application, a hydrogen isotope swing adsorption system and a control method. The composite adsorbent is used for hydrogen isotope separation; the raw material composition comprises 75 wt%-85 wt% of insulating type molecular sieves, 10 wt%-20 wt% of conductive type activated carbon and 5 wt%-10 wt% of an organic binder. The composite adsorbent has high adsorption selectivity and excellent conductive performance, and can efficiently separate and purify hydrogen isotopes (D2 / H2) in an ultralow temperature environment. In the preparation process of the composite adsorbent, in-situ carbonization is carried out by using the organic binder to construct a continuous amorphous carbon conductive network, the functional integration of the insulating type molecular sieves and the conductive type activated carbon is realized, and efficient, low-energy-consumption and long-service-life electric regeneration swing adsorption (ETSA) cycle operation is realized near the liquid nitrogen temperature zone (70-90 K).

Description

Technical Field

[0001] This invention belongs to the field of gas separation technology, specifically relating to a composite adsorbent and raw material composition and preparation method, application, and a hydrogen isotope temperature-varying adsorption system and control method, which is applicable to scenarios requiring high-purity isotopes, such as nuclear industry isotope preparation and fusion fuel purification. Background Technology

[0002] The efficient separation of hydrogen isotopes (especially deuterium (D2) and hydrogen (H2) is a crucial foundational step in cutting-edge scientific and technological fields such as nuclear fusion energy, isotope pharmaceutical preparation, quantum information science, and the synthesis of advanced materials. With the advancement of the International Thermonuclear Experimental Reactor (ITER) project and the development of future commercial fusion reactors (such as DEMO), the demand for high-purity deuterium is increasing. Achieving online purification and recovery of H2 / D2 / T2 in the fuel cycle system has become one of the core technological bottlenecks restricting the sustainable development of fusion energy.

[0003] Among numerous hydrogen isotope separation technologies, cryogenic adsorption is widely considered one of the most promising engineering application paths due to its advantages such as operating temperature matching the liquid nitrogen temperature range (70-90 K), relatively low energy consumption, compact equipment, and ease of integration. However, traditional cryogenic adsorption processes heavily rely on external heat sources for adsorbent regeneration, which not only leads to significant cooling losses and damages the thermodynamic stability of the cryogenic system, but also results in long regeneration cycles, high energy consumption, and difficulty in achieving rapid cyclic operation, greatly limiting its deployment capability in continuous and intelligent nuclear facilities.

[0004] Currently, mainstream adsorption materials can be divided into two categories: one is molecular sieves (such as 5A and 13X zeolites), which have regular microporous structures and highly polar surfaces. They can achieve highly selective adsorption of D2 / H2 through size sieving and dipole-quadrupole interactions (kinetic diameters are 0.24 nm and 0.22 nm, respectively). However, they are essentially ionic crystals, electronically insulating, and cannot be directly heated by electricity. The other is carbon-based materials (such as activated carbon, carbon nanotubes, and graphene), which have excellent conductivity and certain adsorption capacity. However, their selectivity for light isotopes is generally poor, making it difficult to meet the requirements for high-purity separation.

[0005] Both have significant drawbacks when used independently—if molecular sieves are used, regeneration requires external heating, leading to severe cold-end disturbances; if carbon materials are used, separation efficiency must be sacrificed for electrically heatable performance. Therefore, the fundamental contradiction between "high adsorption selectivity" and "good conductivity" has long hindered the evolution of low-temperature adsorption technology towards intelligence and low energy consumption.

[0006] Traditional temperature swing adsorption (TSA) or pressure swing adsorption (PSA) processes face severe challenges under ultra-low temperature conditions: External heating requires the introduction of additional thermal bridges, causing a surge in the load on the refrigeration system; uneven heat conduction can easily lead to local overheating or temperature lag, resulting in adsorbent sintering, pulverization, or micropore collapse; regeneration time can be as long as several hours, seriously affecting system operating efficiency; high energy consumption and poor economic efficiency.

[0007] Although previous studies have attempted to embed metal wires into the bed to achieve internal Joule heating, problems such as high contact resistance between the metal and particles, uneven heat transfer, and poor mechanical compatibility have made it difficult to achieve a rapid, uniform, and controllable heating process. Furthermore, metal components are prone to brittle fracture at low temperatures, resulting in insufficient long-term cycling reliability.

[0008] In recent years, electrically-driven temperature-swing adsorption (ETSA) has attracted widespread attention as a novel energy-coupled separation mode. This technology achieves in-situ, rapid, and uniform heating by applying an electric current to a functionalized adsorption bed and utilizing the Joule heating effect of the material itself. This avoids the cold energy leakage problem caused by traditional heating and can theoretically significantly reduce regeneration energy consumption and improve system response speed.

[0009] However, the core prerequisite for ETSA technology is the development of bifunctional composite adsorbents that combine high adsorption performance with excellent conductivity. Existing attempts mainly focus on methods such as surface coating with conductive layers (e.g., CVD-deposited carbon films) and mixing with conductive fillers (e.g., carbon black, graphene), but these methods generally suffer from the following drawbacks: discontinuous conductive networks, high resistivity (>1 Ω·m), and low heating efficiency; weak interfacial bonding between the conductive and adsorbed phases, making them prone to detachment during cycling; complex processes, high costs, and difficulty in large-scale preparation; and high-temperature treatment may damage the original pore structure, affecting adsorption performance.

[0010] Therefore, the key to realizing the transition of ETSA technology from the laboratory to engineering applications lies in how to construct an electroregenerative composite adsorbent with stable structure, continuous conductive pathways, excellent adsorption performance, and large-scale production capability. Summary of the Invention

[0011] To overcome the technical problems of "highly selective adsorbents being non-conductive and conductive materials having poor adsorption performance" in traditional low-temperature gas separation technologies, and to break through the key technical bottlenecks of high energy consumption, large cold loss, and slow regeneration speed in existing temperature-variable adsorption processes, this invention provides a composite adsorbent and raw material composition, preparation method, application, and a hydrogen isotope temperature-variable adsorption system and control method. This composite adsorbent combines high adsorption selectivity with excellent conductivity, enabling efficient separation and purification of hydrogen isotopes (D2 / H2) under ultra-low temperature conditions. In the preparation process of the composite adsorbent, in-situ carbonization using an organic binder constructs a continuous amorphous carbon conductive network, achieving functional integration of insulating molecular sieves and conductive activated carbon. This enables efficient, low-energy-consumption, and long-life electro-regenerative temperature-variable adsorption (ETSA) cyclic operation near the liquid nitrogen temperature range (70-90 K).

[0012] The present invention achieves the above objectives through the following technical solutions: This invention discloses a raw material composition for a composite adsorbent, wherein the composite adsorbent is used for hydrogen isotope separation; the raw material composition comprises: 75 wt%-85 wt% insulating molecular sieves 10 wt%-20 wt% conductive activated carbon, 5 wt%-10 wt% organic binder; Here, wt% refers to the percentage of the mass of each component relative to the total mass of the raw material composition.

[0013] Understandably, the hydrogen isotope separation refers to the separation of hydrogen (H2) and deuterium (D2), and this separation process is carried out in an ultra-low temperature environment, such as 70-90 K, where K is a unit of thermodynamic temperature.

[0014] In this invention, the insulating molecular sieve can be insulating molecular sieve particles, which are used to provide a high specific surface area and a polar surface; based on the difference in kinetic diameter: D2 is 0.24 nm and H2 is 0.22 nm, selective adsorption of D2 is achieved.

[0015] In some embodiments, the insulating molecule is selected from at least one of 5A zeolite and 13X zeolite; wherein 5A zeolite and 13X zeolite have strong adsorption capacity and high selectivity for deuterium gas.

[0016] In some embodiments, the particle size of the insulating molecular sieve is 50-200 μm; the smaller the particle size of the molecular sieve, the larger its specific surface area, which is beneficial for bonding with activated carbon and organic binders.

[0017] In this invention, the conductive activated carbon can be conductive activated carbon micro powder, which can enhance local conductivity and synergistically improve the overall adsorption capacity and mass transfer efficiency.

[0018] In some embodiments, the average particle size of the conductive activated carbon is ≤50 μm.

[0019] In some embodiments, the specific surface area of ​​the conductive activated carbon is ≥1000 m². 2 / g.

[0020] In this invention, the organic binder can be a water-soluble polymer compound, which is transformed into a continuous amorphous carbon conductive network after carbonization, thus achieving the dual functions of molding and conductivity.

[0021] In some embodiments, the organic binder is selected from at least one of sodium carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and phenolic resin precursor; the amount of the organic binder added is 5%-10% of the total mass of the raw material composition.

[0022] In this invention, by following the above-mentioned raw material components and their proportions, both the adsorption of deuterium gas by the composite adsorbent at ultra-low temperatures and the desorption of deuterium gas by electrostatic regeneration of the composite adsorbent are achieved. Specifically, the insulating molecular sieve is used to enhance the adsorption capacity; the conductive activated carbon is used to meet the conductivity requirements; and the organic binder undergoes pyrolysis and carbonization during the preparation process, generating a continuously distributed amorphous carbon conductive network, effectively interconnecting the molecular sieve and activated carbon.

[0023] The present invention also provides a method for preparing a composite adsorbent, which utilizes the raw material composition described above and includes the following steps: The raw material composition is mixed and dispersed in a solvent to form a slurry; The slurry is sequentially subjected to granulation and drying processes to obtain granules; Under a protective atmosphere, the particles are held at 290-310 °C for 1-4 h for low-temperature in-situ carbonization, so that the organic binder is transformed into an amorphous carbon phase with electronic conductivity. After cooling and sieving, a composite adsorbent is obtained.

[0024] In this invention, the temperature conditions for low-temperature in-situ carbonization are 290-310 ℃. When the temperature is below 290 ℃, the organic binder is not completely carbonized, resulting in insufficient conductivity and a sharp increase in resistivity of the composite adsorbent. When the temperature is above 310 ℃, it may cause dealuminization of the molecular sieve or collapse of the micropores in the molecular sieve, thereby affecting the adsorption of the composite adsorbent and drastically reducing its adsorption capacity for the adsorbate.

[0025] In some embodiments, the solvent includes a polar solvent, such as water.

[0026] In some embodiments, the dispersion method includes ball milling or ultrasonic dispersion.

[0027] In some embodiments, the granulation method includes spray drying, extrusion molding, or spheroidization.

[0028] In some embodiments, after granulation, the particles are spherical or polyhedral in shape; the diameter of the particles is 1-3 mm.

[0029] In some embodiments, the drying process is carried out at a temperature of 80-120 °C.

[0030] In some embodiments, the protective atmosphere includes a nitrogen atmosphere or an argon atmosphere.

[0031] In some embodiments, the low-temperature in-situ carbonization reaction is carried out in a tube furnace.

[0032] In one embodiment, the preparation method includes the following steps: Insulating molecular sieve particles, conductive activated carbon micro powder and organic binder are mixed in proportion and ground and dispersed in solvent to form a homogeneous suspension slurry, ensuring that each component is fully wetted and there is no agglomeration. The slurry is granulated into spherical or polyhedral particles, dried to remove the solvent, and a preform with preliminary mechanical strength is obtained. Under a nitrogen or argon protective atmosphere, the dried particles are held at a temperature range of 290-310 ℃ for 1-4 h for low-temperature in-situ carbonization to generate a carbon-rich amorphous structure. During this process, the organic binder is transformed into an amorphous carbon phase with electronic conductivity, forming a conductive path that runs through the entire particle. The electro-regenerated composite adsorbent with dual functional properties is obtained by cooling to room temperature and sieving.

[0033] The present invention also provides a composite adsorbent, which is prepared by the preparation method described above; the composite adsorbent comprises an insulating molecular sieve, conductive activated carbon and an amorphous carbon conductive network, wherein the insulating molecular sieve and the conductive activated carbon are interconnected through the amorphous carbon conductive network.

[0034] In this invention, the composite adsorbent is an integrated particulate material formed by in-situ carbonization of an insulating molecular sieve, conductive activated carbon, and an organic binder. The carbon phase obtained by the organic binder not only plays a role in strong bonding between particles, but also forms a three-dimensional electronic conduction network that runs through the entire composite particle, effectively bridging the insulating molecular sieve and the conductive activated carbon, and realizing "internal biochemical conduction channels, structural integration, and functional synergy", thus avoiding the problems of interface loosening, resistance increase, and cycle failure caused by the addition of external conductive fillers.

[0035] In some embodiments, the resistivity of the composite adsorbent is <0.3 Ω·m, which meets the conductivity requirements for Joule heating.

[0036] In some embodiments, the composite adsorbent adsorbs ≥4.5 mmol / g of D2 at 77 K.

[0037] In some embodiments, the composite adsorbent exhibits a dynamic adsorption selectivity for D2 / H2 greater than 1.8; this means that, under non-equilibrium conditions, the composite adsorbent has a preferential adsorption capacity for D2 that is more than 1.8 times that for H2.

[0038] In this invention, the composite adsorbent has high particle strength and a crushing rate of less than 5%, making it suitable for long-term operation in a fixed bed.

[0039] The present invention also provides an application of the composite adsorbent described above in hydrogen isotope separation.

[0040] In this invention, the application of hydrogen isotope separation includes online purification and recovery of deuterium in nuclear fusion fuel cycles.

[0041] The present invention also provides a hydrogen isotope temperature-varying adsorption system, which includes a low-temperature adsorption tower, wherein the low-temperature adsorption tower has an electrode built in it, and a composite adsorbent as described above; the composite adsorbent is embedded in the electrode to form a functionalized bed.

[0042] In some embodiments, the electrode comprises a mesh stainless steel electrode.

[0043] In some embodiments, the hydrogen isotope temperature-varying adsorption system is equipped with a temperature control module, which is used to monitor the temperature of the functionalized bed in real time and adjust the input voltage of the electrode according to the feedback, thereby controlling the temperature rise rate and the maximum temperature; the temperature control module has a temperature control accuracy of ±2 K, which can avoid local overheating that could damage the adsorbent structure.

[0044] In this invention, the hydrogen isotope temperature-varying adsorption system also includes an automated control module, which is electrically connected to the low-temperature adsorption tower to realize the programmed operation of the entire process of "adsorption-heating desorption-cooling".

[0045] The present invention also provides a control method for the hydrogen isotope temperature-varying adsorption system as described above, which includes the following two stages: Adsorption stage: The hydrogen isotope temperature-varying adsorption system is controlled to operate at 70-90 K, and the composite adsorbent is used to selectively capture D2 from the mixed gas, which includes H2 and D2. Desorption stage: Apply a DC voltage of 20-200 V to the electrode to induce a Joule heating effect in the functionalized bed, and raise the temperature of the functionalized bed to 150-180 K within ≤20 min; desorb D2 adsorbed in the composite adsorbent.

[0046] In the adsorption stage of this invention, while capturing D2, H2 with a purity >99.9% can be collected at the gas outlet of the low-temperature adsorption tower.

[0047] In one embodiment, during the adsorption stage: the hydrogen isotope temperature-varying adsorption system is controlled to be in the liquid nitrogen temperature range (70-90 K), and a gas containing H2 / D2 is introduced into the low-temperature adsorption tower. D2 is selectively captured in the micropores, and the purity of H2 in the outlet gas is >99.9%.

[0048] In the desorption stage of this invention, vacuum desorption or inert gas purging can be used to achieve efficient desorption and recovery of D2.

[0049] In one embodiment, a DC voltage of 20-200 V is applied to the electrode, at which time the bed is heated to 150-180 K by Joule heating. Combined with vacuum suction or He / N2 purging, a high concentration of D2 mixed gas is released. The regeneration time is ≤20 min and the D2 recovery rate is >98%.

[0050] Compared with the prior art, the present invention has the following significant advantages: 1. This invention constructs a continuous conductive network through the carbonization of an organic binder, achieving synergistic integration of insulating molecular sieve and conductive activated carbon. The resulting composite adsorbent not only forms an electron transport channel throughout the entire particle, significantly reducing the overall resistivity, but also maintains the integrity of the microporous structure of the molecular sieve body, ensuring its high adsorption capacity for D2 and high D2 / H2 selectivity at liquid nitrogen temperature of 77 K.

[0051] 2. The preparation method of the composite adsorbent of the present invention is characterized by its simple and controllable process, which does not require complex coating, deposition or high-temperature graphitization processes, making it suitable for large-scale production. The composite adsorbent of the present invention has the characteristics of strong structural stability and strong performance adjustability, specifically manifested in that: the carbonization products are covalently / physically interpenetrating with the host material, and have strong resistance to cyclic shearing; by adjusting the type and content of the binder and the carbonization parameters, the balance between conductivity and porosity retention can be precisely adjusted.

[0052] 3. The hydrogen isotope temperature-varying adsorption system containing the composite adsorbent of this invention has the following characteristics: (1) low regeneration energy consumption (saving about 33%-40% energy compared to traditional external heating methods); (2) fast temperature rise rate and uniform temperature distribution (maximum temperature difference <2 K, combined with ±2 K precision temperature control, effectively preventing structural deterioration caused by local overheating); (3) good cycle stability (after more than 20 consecutive runs, the adsorption capacity retention rate is ≥95%); (4) no cold bridge interference (the heat source is from the material itself, not dependent on external heat sources, greatly reducing the load on the refrigeration system). The general-purpose electro-regenerative adsorption system constructed in this way is expected to replace the traditional high-energy-consuming cryogenic distillation and chemical exchange processes, and promote the transformation and upgrading of the gas separation industry towards green, intelligent and modular directions.

[0053] 4. The design concept of "constructing a conductive network with carbonized binder" can be extended to He / Ne, 12 C / 13 C 14 N / 15 The cryogenic separation system for nitrogen and other light gas isotopes or rare gases is used as a general-purpose electro-regenerative adsorption platform technology. Its value lies not only in resolving the energy consumption and efficiency contradiction in cryogenic gas separation, but also in pioneering a technical route of "material self-generated thermal regeneration," providing a new methodology for intelligent material design in multidisciplinary fields. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0055] Figure 1 The results of DTA tests on the carbonization process of the raw material compositions of the composite adsorbents in Examples 2 and 4 of this invention under a nitrogen atmosphere; Figure 2 This is a SEM image of the composite adsorbent in Example 2 of the present invention; Figure 3 This is a SEM image of the composite adsorbent in Example 4 of the present invention. Detailed Implementation

[0056] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so as to better understand the purpose, features and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the present invention, but are only for illustrating the essential spirit of the technical solution of the present invention.

[0057] In the following description, certain specific details are set forth for the purpose of illustrating various disclosed embodiments in order to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the art will recognize that the embodiments may be practiced without one or more of these specific details. In other instances, well-known apparatuses, structures, and techniques associated with this application may not have been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0058] Throughout this specification, references to "one embodiment" or "one embodiment" indicate that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. Therefore, the appearance of "one embodiment" or "one embodiment" in various places throughout the specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any manner in one or more embodiments.

[0059] In the following description, in order to clearly demonstrate the structure and operation of the present invention, a number of directional terms will be used. However, terms such as "front", "back", "left", "right", "outside", "inside", "outward", "inward", and "up and down" should be understood as convenient terms and not as limiting terms.

[0060] It should be noted that the features shown in the accompanying drawings of this application may belong to one embodiment or different embodiments, as long as there is no conflict between these features. To save space, this application may use the same drawing to illustrate different embodiments; that is, the same drawing of this application may be used to illustrate features in different embodiments.

[0061] In this invention, the simplest electroregenerative temperature-switching adsorption (ETSA) cycle includes three steps: Feed: A gaseous mixture containing the substances to be separated is fed into the adsorption bed at low temperature. Substances with a strong affinity for the adsorbent (heavy component compounds) are retained within the adsorbent packed in the adsorption bed, while substances with a weaker affinity (light component compounds) are recovered at the column outlet of the adsorption bed.

[0062] Electrostatic regeneration: Following the feed step, the adsorption bed is energized and heated (Joule effect). During energization, a counter-current purge stream is introduced into the adsorption bed. The purge stream helps remove desorbed molecules from the adsorption bed and also plays a role in adsorbate desorption by reducing their partial pressure in the gas phase. At the end of electrodesorption, the maximum temperature is reached, and the adsorbent is (partially) regenerated. In this step, heavy component compounds are recovered at the feed end.

[0063] Cooling: After removing the adsorbate from the adsorption bed, the adsorbent temperature needs to be reduced to restore its adsorption performance and begin a new ETSA cycle. During the cooling step, purge gas can be used to lower the adsorption bed temperature.

[0064] Example 1 This embodiment discloses a composite adsorbent based on a 5A zeolite / activated carbon / sodium carboxymethyl cellulose (CMC) system and its preparation method.

[0065] The raw material composition of the composite adsorbent in this embodiment contains: 75 wt% 5A zeolite (particle size 80-120 μm) and 20 wt% activated carbon micro powder (specific surface area 1200 m²). 2 / g, average particle size 40 μm) and 5 wt% sodium carboxymethyl cellulose (CMC, viscosity about 400 cP).

[0066] The preparation method of the composite adsorbent in this embodiment is as follows: S1. Slurry preparation: According to the proportion, add the above components to the mixing container in sequence, and add deionized water to control the solid content to 70%-90%; first, stir at low speed (300 rpm) for 10 minutes to wet, then shear at high speed (1500 rpm) for 30 minutes; then perform auxiliary ultrasonic treatment (power 200 W, frequency 40 kHz) for 15 minutes to ensure no agglomeration, and obtain the slurry.

[0067] CMC is an anionic polymer that dissociates in water to form -COO. - Groups stabilize the suspension system through electrostatic repulsion; oxygen-containing functional groups on the surface of activated carbon interact with CMC via hydrogen bonding, enhancing interfacial compatibility; Brownian motion between micron-sized particles is effectively suppressed, achieving long-term sedimentation stability.

[0068] S2, Granulation and molding: The slurry was put into an extruder and extruded to form wet granules with a diameter of 3 mm; the wet granules were placed in a forced-air drying oven and dried at a constant temperature of 105 ℃ for 4 h to remove residual moisture and obtain granules. S3, In-situ low-temperature carbonization: The particles were placed in a nitrogen-protected tube furnace (PYRO Classic LabTech) with a nitrogen flow rate of 50 mL / min. The temperature was then programmed to rise at a rate of 2 °C / min, and the particles were pyrolyzed and carbonized at 290-310 °C for 4 h. After carbonization, the particles were cooled to room temperature and then sieved to obtain composite adsorbent samples.

[0069] The composite adsorbent sample was characterized (resistivity testing, morphology observation (SEM), phase analysis (XRD / XPS), and low-temperature adsorption performance evaluation): (1) SEM showed that the CMC pyrolysis products were encapsulated in filamentous carbon films and bridged 5A zeolite and activated carbon; (2) The resistivity measured by the four probes was 0.26 Ω·m; (3) At 77 K, the adsorption capacity of D2 is 4.91 mmol / g, H2 is 2.65 mmol / g, and the selectivity is 1.85.

[0070] Application Example 1 This application example discloses a hydrogen isotope temperature-varying adsorption system.

[0071] A PTFE adsorption tower (Φ50 mm × 800 mm) is used; it is equipped with a double-layer mesh 316L stainless steel electrode embedded bed, which is filled with the adsorbent of Example 1, with an effective adsorption length of 500 mm. The stainless steel electrodes are connected to a DC power supply (20-220 V adjustable); thus, a complete electro-regenerative temperature-switching adsorption (ETSA) system is constructed to achieve fully automatic cyclic operation.

[0072] The inlet of the adsorption tower is connected to an H2 / D2 mixed gas source, which consists of 99% H2 and 1% D2; the outlet is connected to a GC-MS (Agilent 8860-5977) for online analysis of the outlet gas; the adsorption tower is also connected to a vacuum pump and a cold trap for the desorption and recovery of D2.

[0073] The control method of the hydrogen isotope temperature-varying adsorption system in this application embodiment is as follows: (1) Adsorption stage: The hydrogen isotope temperature-varying adsorption system is controlled to operate at 70-90 K, and the composite adsorbent is used to selectively capture D2 from the mixed gas; (2) Desorption stage: Apply a DC voltage of 20-200 V to the electrode to induce a Joule heating effect in the functionalized bed, and raise the temperature of the functionalized bed to 150-180 K within ≤20 min; desorb D2 adsorbed in the composite adsorbent.

[0074] One adsorption and one desorption constitute one ETSA cycle.

[0075] The energy efficiency of the hydrogen isotope temperature-varying adsorption system in this application embodiment is calculated to be as high as 37.6%.

[0076] The results obtained after 20 ETSA cycles are shown in Table 1. Table 1 compares the initial performance of the composite adsorbent with its performance after 20 cycles.

[0077] Table 1

[0078] As shown in the table above, the system has good cyclic stability. After 20 cycles, the composite adsorbent still has a high adsorption capacity for D2, while the resistivity, particle breakage rate and H2 purity in the outlet gas increase slightly.

[0079] The reasons for the decline in the performance of the composite adsorbent after adsorption-desorption cycles may be as follows: (1) Despite the protection of an inert atmosphere, trace amounts of oxygen may intrude during repeated heating, leading to slight oxidation of the carbon phase; (2) repeated heating at 77 K Thermal expansion and contraction at 160 K causes microcracks in particles, leading to thermal stress fatigue; (3) The metal-carbon interface experiences a rise in micro-contact resistance after long-term current impact, resulting in electrode contact degradation.

[0080] Example 2 This embodiment discloses a composite adsorbent based on a 5A zeolite / activated carbon / sodium carboxymethyl cellulose (CMC) system and its preparation method.

[0081] The raw material composition of the composite adsorbent in this embodiment contains: 78 wt% 5A zeolite (particle size 80-120 μm) and 17 wt% activated carbon micropowder (specific surface area 1200 m²). 2 / g, average particle size 40 μm) and 5 wt% sodium carboxymethyl cellulose (CMC, viscosity about 400 cP).

[0082] The preparation method of the composite adsorbent in this embodiment is the same as that in Example 1.

[0083] The composite adsorbent was characterized, and the results are shown in Table 2. Table 2 presents the performance data of the composite adsorbent prepared in this embodiment.

[0084] Table 2

[0085] Figure 1 The results of DTA (STA2500, Netzsch) tests on the carbonization process of the raw material compositions of the composite adsorbents in Examples 2 and 4 under a nitrogen atmosphere are shown. Figure 1 As shown, the DTA (differential thermal analysis) curve of the composite adsorbent (black line) in this embodiment is in the minimum range between 290-310 °C, and the DTA value of the composite adsorbent in this embodiment is the smallest at 293 °C.

[0086] Using a JSM-7800F SEM instrument from JEOL Corporation of Japan, the composite adsorbent in this embodiment was scanned to obtain... Figure 2 ; Figure 2Here is a SEM image of the composite adsorbent in this embodiment, as shown. Figure 2 The CMC pyrolysis product shown is used to bridge 5A zeolite and activated carbon.

[0087] Example 3 This embodiment discloses a composite adsorbent based on a 5A zeolite / activated carbon / polyvinyl alcohol (PVA) system and its preparation method.

[0088] Except for replacing sodium carboxymethyl cellulose (CMC) in Example 2 with polyvinyl alcohol (PVA) and using hot water at 80 °C to dissolve the raw material composition during slurry preparation, the other components of the raw material composition and the preparation method of the composite adsorbent in this example are the same as in Example 2.

[0089] The composite adsorbent was characterized, and the results are shown in Table 3. Table 3 presents the performance data of the composite adsorbent prepared in this embodiment.

[0090] Table 3

[0091] Example 4 This embodiment discloses a composite adsorbent based on a 5A zeolite / activated carbon / sodium carboxymethyl cellulose (CMC) system and its preparation method.

[0092] The raw material composition of the composite adsorbent in this embodiment contains: 85 wt% 5A zeolite (particle size 80-120 μm) and 10 wt% activated carbon micro powder (specific surface area 1200 m²). 2 / g, average particle size 40 μm) and 5 wt% sodium carboxymethyl cellulose (CMC, viscosity about 400 cP).

[0093] The preparation method of the composite adsorbent in this embodiment is the same as that in Example 2.

[0094] The composite adsorbent was characterized, and the results are shown in Table 4. Table 4 presents the performance data of the composite adsorbent prepared in this embodiment.

[0095] Table 4

[0096] like Figure 1 As shown, the DTA (differential thermal analysis) curve of the composite adsorbent (red line) in this embodiment is in the minimum range between 290-310 °C, and the DTA value of the composite adsorbent in this embodiment is the smallest at 296.8 °C.

[0097] Using a JSM-7800F SEM instrument from JEOL Corporation of Japan, the composite adsorbent in this embodiment was scanned to obtain... Figure 3 ; Figure 3 Here is a SEM image of the composite adsorbent in this embodiment, as shown. Figure 3 The CMC pyrolysis product shown is used to bridge 5A zeolite and activated carbon.

[0098] Comparative Example 1 This comparative example discloses an adsorbent that contains no organic binder.

[0099] The raw material composition of this comparative adsorbent contains: 83 wt% 5A zeolite (particle size 80-120 μm) and 17 wt% activated carbon micropowder (specific surface area 1200 m²). 2 / g, average particle size 40 μm).

[0100] The adsorbents in this comparative ratio were directly compressed into tablets after mechanical mixing.

[0101] The adsorbent was characterized and found to have a resistivity greater than 1 Ω·m; a breakage rate of 23% after 10 cycles; and no carbon bridges connecting the particles, resulting in a low bed packing density. This verifies the necessity of organic binder carbonization for the construction of the conductive network.

[0102] Comparative Example 2 This comparative example discloses a composite adsorbent based on a 5A zeolite / activated carbon / sodium carboxymethyl cellulose (CMC) system and its preparation method.

[0103] The raw material composition formulation for this comparative example is the same as that in Example 2. However, in the preparation of the composite adsorbent, a carbonization temperature of 350 °C was used during the in-situ carbonization in step S3 to obtain the composite adsorbent. At this carbonization temperature, the structure of the molecular sieve was destroyed.

[0104] The adsorbent was characterized, and the results are shown in Table 5. Table 5 presents the performance data of the composite adsorbent prepared in this comparative example.

[0105] Table 5

[0106] Therefore, Examples 1-4 demonstrate that by precisely controlling the ternary system of "zeolite-activated carbon-binder" and controlling the pyrolysis temperature, adsorption performance (Example 4) or conductivity can be optimized in a targeted manner; since Comparative Examples 1 and 2 omit the binder and deviate from the carbonization temperature window, the technical effect cannot be achieved.

[0107] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0108] Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the invention.

[0109] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, system, or module that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, system, or module. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, system, or module that includes said element.

[0110] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A temperature-variable adsorption system for hydrogen isotopes, characterized in that, It includes a low-temperature adsorption tower, which has electrodes built in it, and a composite adsorbent for hydrogen isotope separation; the composite adsorbent is embedded in the electrodes to form a functionalized bed. The raw material composition of the composite adsorbent includes: 75 wt%-85 wt% of insulating molecular sieve, 10 wt%-20 wt% of conductive activated carbon, and 5 wt%-10 wt% of organic binder; wherein, wt% refers to the percentage of the mass of each component to the total mass of the raw material composition; The preparation method of the composite adsorbent includes the following steps: The raw material composition is mixed and dispersed in a solvent to form a slurry; The slurry is sequentially subjected to granulation and drying processes to obtain granules; Under a protective atmosphere, the particles are held at 290-310 °C for 1-4 h for low-temperature in-situ carbonization, so that the organic binder is transformed into an amorphous carbon phase with electronic conductivity. After cooling and sieving, a composite adsorbent is obtained; The composite adsorbent comprises an insulating molecular sieve, conductive activated carbon, and an amorphous carbon conductive network, wherein the insulating molecular sieve and the conductive activated carbon are interconnected through the amorphous carbon conductive network.

2. The hydrogen isotope temperature-varying adsorption system as described in claim 1, characterized in that, The electrode includes a mesh stainless steel electrode; The hydrogen isotope temperature-varying adsorption system is equipped with a temperature control module, which is used to monitor the temperature of the functionalized bed in real time and adjust the input voltage of the electrode according to the feedback; the temperature control accuracy of the temperature control module is ±2 K.

3. The hydrogen isotope temperature-varying adsorption system as described in claim 1, characterized in that, The raw material composition satisfies at least one of the following conditions: i. The insulating molecule is selected from at least one of 5A zeolite and 13X zeolite; ii. The particle size of the insulating molecular sieve is 50-200 μm; iii. The average particle size of the conductive activated carbon is ≤50 μm; iv. The specific surface area of ​​the conductive activated carbon is ≥1000 m². 2 / g; v. The organic binder is selected from at least one of sodium carboxymethyl cellulose, polyvinyl alcohol, and phenolic resin precursors.

4. The hydrogen isotope temperature-varying adsorption system as described in claim 1, characterized in that, The preparation method satisfies at least one of the following conditions: i. The solvent includes polar solvents; ii. The dispersion method includes ball milling dispersion or ultrasonic dispersion; iii. The granulation method includes spray drying, extrusion molding, or spheroidization. iv. After granulation, the particles are spherical or polyhedral in shape; the diameter of the particles is 1-3 mm. v. The drying temperature is 80-120 ℃; vi. The protective atmosphere includes a nitrogen atmosphere or an argon atmosphere; vii. The low-temperature in-situ carbonization reaction is carried out in a tube furnace.

5. The hydrogen isotope temperature-varying adsorption system as described in claim 1, characterized in that, The composite adsorbent satisfies at least one of the following conditions: i. The resistivity of the composite adsorbent is <0.3 Ω·m; ii. The adsorption capacity of the composite adsorbent for deuterium D2 at 77 K is ≥4.5 mmol / g; iii. The composite adsorbent exhibits a dynamic adsorption selectivity greater than 1.8 for deuterium (D2) / hydrogen (H2).

6. A control method for a hydrogen isotope temperature-varying adsorption system as described in any one of claims 1-5, characterized in that, It includes the following two stages: Adsorption stage: The hydrogen isotope temperature-varying adsorption system is controlled to operate at 70-90 K, and the composite adsorbent is used to selectively capture deuterium D2 from the mixed gas, which includes hydrogen H2 and deuterium D2. Desorption stage: Apply a DC voltage of 20-200 V to the electrode to induce a Joule heating effect in the functionalized bed, and raise the temperature of the functionalized bed to 150-180 K within ≤20 min; desorb the deuterium D2 adsorbed in the composite adsorbent.

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