A packing material, a chromatographic column and a method for preparing a chromatographic column

Abstract

The packing material, chromatographic column, and preparation method of the chromatographic column provided in this application embodiment are used for the separation of hydrogen isotopes by thermal cycling adsorption. The packing material includes a hydrogen storage material with hydrogen isotope effect and natural graphite, which are uniformly mixed. By setting the packing material to include a hydrogen storage material with hydrogen isotope effect and natural graphite, the thermal conductivity of natural graphite is more than an order of magnitude higher than that of expanded graphite, and its density is 150-300 times greater than that of expanded graphite. Therefore, under the premise of a certain mass, the volume occupied is smaller, the corresponding hydrogen adsorption capacity is higher, and the hydrogen isotope separation efficiency is better. By using natural graphite as a thermal conductivity enhancer, the thermal conductivity of the packing material is improved while minimizing the impact on the saturated hydrogen adsorption capacity. In addition, natural graphite is soft and highly lubricating, and its flowability is better than that of metal foam and hydrogen storage material when packed, making it easier to fill the voids in the chromatographic column, which is beneficial to the preparation of the chromatographic column.

Description

Technical Field

[0001] This application relates to the field of gas phase separation chromatography column technology, and in particular to a packing material, a chromatography column, and a method for preparing the chromatography column. Background Technology

[0002] This section is intended to provide background or context for the embodiments described in this application. The description herein is not intended to be a prior art simply because it is included in this section.

[0003] Thermal Cycling Absorption Process (TCAP) is a semi-continuous chromatographic process. TCAP operation requires temperature cycles of heating and cooling to allow hydrogen isotopes to flow within the system and achieve isotope separation. Taking palladium as the hydrogen storage material as an example, the adsorption-desorption of hydrogen isotopes by Pd is a reversible process. The hydrogen absorption reaction is exothermic, requiring timely removal of the generated heat to ensure its full progress. Conversely, the hydrogen release reaction is endothermic, necessitating rapid replenishment of heat to fully release the adsorbed hydrogen from Pd. The single cycle time here is actually the sum of the time required for Pd to fully adsorb hydrogen during cooling and the time required for Pd to fully release hydrogen during heating. To shorten the cycle time and improve hydrogen isotope separation efficiency, external heating or cooling must be rapidly and effectively conducted to the Pd element in the chromatographic column. Therefore, how to shorten the single cycle time and improve separation efficiency by packing the chromatographic column with a material with good thermal conductivity is one of the research topics in the industry. Summary of the Invention

[0004] In view of this, the embodiments of this application aim to provide a packing material with good thermal conductivity, a chromatographic column, and a method for preparing the chromatographic column, so as to improve the separation efficiency of hydrogen isotopes.

[0005] To achieve the above objectives, one aspect of this application provides a filling material for separating hydrogen isotopes using a thermal cycling adsorption method. The filling material comprises a hydrogen storage material with a hydrogen isotope effect and natural graphite, wherein the hydrogen storage material and the natural graphite are uniformly mixed.

[0006] In some embodiments, the natural graphite includes at least one of natural flake graphite, amorphous graphite, and massive graphite.

[0007] In some embodiments, the particle size of the natural graphite is 20-40 mesh.

[0008] In some embodiments, the particle size of the natural graphite is 380 μm-830 μm.

[0009] In some embodiments, the weight percentage of the natural graphite is less than or equal to 1 wt%.

[0010] In some embodiments, the natural graphite comprises 0.2wt%-0.5wt% by weight.

[0011] In some embodiments, the hydrogen storage material includes at least one of pure palladium powder, palladium-diatomite, palladium-molecular sieve, and palladium-α-alumina.

[0012] In some embodiments, the hydrogen storage material is palladium-diatomite, wherein the palladium in the palladium-diatomite has a weight percentage of 40wt%-70wt%.

[0013] In some embodiments, the particle size of the hydrogen storage material is 0.1 mm to 1 mm.

[0014] Another aspect of this application provides a chromatographic column for separating hydrogen isotopes by thermal cycling adsorption. The chromatographic column includes a container and the packing material described above, wherein the packing material is disposed within the container.

[0015] Another aspect of this application provides a method for preparing a chromatographic column, the chromatographic column being used for the separation of hydrogen isotopes by thermal cycling adsorption, the chromatographic column comprising a container and the aforementioned packing material, the packing material being disposed within the container, the preparation method comprising:

[0016] The hydrogen storage material and natural graphite are mixed in a certain proportion and stirred evenly to obtain the filler material;

[0017] The filler material is filled into the container;

[0018] The filling material is compacted inside the container.

[0019] The packing material provided in this application embodiment is used for the separation of hydrogen isotopes by thermal cycling adsorption. The packing material includes a hydrogen storage material with hydrogen isotope effect and natural graphite, which are uniformly mixed. By setting the packing material to include a hydrogen storage material with hydrogen isotope effect and natural graphite, the thermal conductivity of natural graphite is more than an order of magnitude higher than that of expanded graphite, and its density is 150-300 times greater than that of expanded graphite. Therefore, under the premise of a certain mass, the volume occupied by the packing material is smaller, the corresponding hydrogen adsorption capacity is higher, and the hydrogen isotope separation efficiency is better. In other words, by using natural graphite as a thermal conductivity enhancer, the thermal conductivity of the packing material is improved while minimizing the impact on the saturated hydrogen adsorption capacity. In addition, natural graphite is soft and highly lubricating, and its flowability is better than that of metal foam and hydrogen storage material when packed, making it easier to fill the voids in the chromatographic column, which is beneficial to the preparation of the chromatographic column. Attached Figure Description

[0020] Figure 1This is a P (pressure)-t (time) curve of saturated hydrogen absorption for five different components of the filler material in one embodiment of this application;

[0021] Figure 2 This is a flowchart illustrating the preparation of a chromatographic column in one embodiment of this application. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and technical features in the embodiments of this application can be combined with each other, and the detailed descriptions in the specific implementation should be understood as explanations of the purpose of this application and should not be regarded as undue limitations on this application.

[0023] Hydrogen exists in nature with three isotopes due to differences in the number of neutrons it contains: protium (H), deuterium (D), and tritium (T). Protium is the most common hydrogen isotope in nature, with an abundance greater than 99.98%, while the less abundant heavy isotopes deuterium and tritium have wide applications in chemistry, chemical engineering, and medicine. Currently, hydrogen isotope separation techniques mainly include cryogenic distillation, thermal diffusion, and chromatographic separation. Thermal Cycling Absorption Process (TCAP) is a semi-continuous chromatographic separation technique.

[0024] Thermal cycling adsorption utilizes the phenomenon of different adsorption / desorption rates and degrees of hydrogen isotopes during the hydrogen absorption and desorption processes of hydrogen storage materials, i.e., the isotope effect. Palladium exhibits the strongest hydrogen isotope effect, preferentially adsorbing lighter hydrogen isotopes during hydrogen absorption and preferentially releasing heavier hydrogen isotopes during hydrogen desorption. The strength of the isotope effect is usually characterized by the separation coefficient, defined as the ratio of T, D, and H concentrations in the metal phase to those in the gas phase.

[0025] For example, the equipment mainly consists of a separation column, a reflux column, and a heating and cooling system. The separation column is filled with pure palladium or palladium-loaded composite material. A mixed gas of hydrogen isotopes is injected from the middle or one end of the separation column. Under the action of the heating and cooling system, the working fluid in the separation column is thermally driven to cycle through hydrogen absorption and desorption. The mixed hydrogen gas flows back and forth between the separation column and the reflux column. After multiple thermally induced hydrogen absorption and desorption cycles, a hydrogen isotope concentration gradient distribution appears in the separation column. Finally, the heavy isotope-enriched product gas is output from the product port, and the light isotope gas is discharged from the tail gas port.

[0026] Taking palladium as a hydrogen storage material as an example, the palladium support is packed into a chromatographic column, which undergoes thermal cycling to achieve isotope separation. Besides temperature and pressure, the separation efficiency of a TCAP column is also affected by a variety of other factors:

[0027] a. Distribution of palladium on diatomite or other carriers in hydrogen storage materials;

[0028] b. The filling density and uniformity of the filler material;

[0029] c. The diameter of the chromatographic column;

[0030] d. Whether there is metal foam or other materials that enhance thermal conductivity in the chromatographic column;

[0031] e. The flow rate of hydrogen isotopes.

[0032] TCAP operation requires temperature cycles of heating and cooling to allow hydrogen isotopes to flow within the system and to separate them in the process. Designing the heating and cooling system has always been a challenge, as both experiments and theory have demonstrated that short cycle times (one heating and one cooling cycle constitutes one cycle) and a wide temperature swing range, from below freezing point or even below liquid nitrogen temperature to above boiling point, are key to improving hydrogen isotope separation efficiency.

[0033] Because the adsorption-desorption of hydrogen isotopes by Pd is a reversible process, and the hydrogen adsorption reaction is exothermic, the generated heat needs to be removed promptly to ensure its full progress. Conversely, the hydrogen release reaction is endothermic, requiring rapid heat replenishment to fully release the adsorbed hydrogen from Pd. The single cycle time here is actually the sum of the time required for Pd to fully adsorb hydrogen during cooling and the time required for Pd to fully release hydrogen during heating. To shorten the cycle time and improve separation efficiency, external heating or cooling must be rapidly and effectively conducted to the Pd element in the palladium support column. Therefore, the thermal conductivity of the packing material within the palladium support column is crucial for shortening the single cycle time.

[0034] Pd-loaded supports, such as diatomaceous earth or α-Al₂O₃, are porous inorganic particulate materials with poor thermal conductivity. To improve thermal conductivity, the diameter of the chromatographic column is generally required to be as small as possible, thereby increasing the heat transfer rate by reducing the distance between the column wall and the packing material. However, the column diameter obviously cannot be reduced indefinitely, because reducing the diameter will lead to a decrease in packing density, an increase in packing difficulty, an increase in column length, and an increase in cost (structural materials, heating / cooling components, etc. will all increase). Another way to improve thermal conductivity is to improve the thermal conductivity of the column packing material itself, such as by adding metal foam (aluminum foam or copper foam, etc.) or other materials with high thermal conductivity inside the column.

[0035] In related technologies, it is hoped that aluminum foam can be used in TCAP columns to improve heat transfer. To investigate the effect of aluminum foam on separation efficiency in chromatographic columns, two 91 cm long and 4.76 cm diameter columns were tested at a flow rate of 610 cm / min, one with aluminum foam and the other without. The results are shown in Table 1 below. The number of stages was 22.1 with aluminum foam and 22.8 without. The length of each stage was 4.5 and 4.4 cm, respectively (more stages resulted in better separation; shorter stage lengths resulted in higher separation efficiency). Considering that aluminum foam replaced approximately 20% of the palladium support volume, reducing the palladium packing density, this offset the beneficial effect of the enhanced thermal conductivity of the metal foam. The two effects canceled each other out, resulting in almost no improvement in separation efficiency between the columns with and without aluminum foam, and even a slight decrease. Ultimately, the difference in results between using aluminum foam and not using it was very small.

[0036] Table 1 Effects of Metal Foam

[0037] Column inner diameter (cm) Should aluminum foam be used? Mean pressure (Torr) Tower length (cm) 4.76 yes 2010 4.5 4.76 No 2010 4.4

[0038] Therefore, in addition to the thermal conductivity of the material itself, other factors need to be considered when adding high thermal conductivity materials to improve the heat transfer performance of the filler, such as shape, hardness, ductility, and compatibility with palladium support, hydrogen isotope gas and structural materials.

[0039] For example, metal foam has high hardness, low bulk density, and low ductility. Therefore, although it has excellent thermal conductivity, it occupies too much volume.

[0040] In related technologies, expanded graphite is a novel carbon material, a loose, porous, worm-like substance obtained from natural graphite flakes through intercalation, washing, drying, and high-temperature expansion (natural graphite expands 150-300 times in volume instantly upon exposure to high temperatures, transforming from flakes into a worm-like shape). Besides possessing the excellent properties of natural graphite, such as resistance to heat and cold, corrosion resistance, self-lubrication, radiation resistance, and strong anti-aging properties, it also exhibits characteristics not found in natural graphite, such as compressive resilience, adsorption, and torsion resistance. Therefore, when added to hydride materials for pressing, a compact that is both dense (expanded graphite is soft, elastic, and deformable) and permeable (expanded graphite is loose and porous) can be obtained, thus giving expanded natural graphite (ENG-MH compact) better hydrogen absorption and desorption kinetics.

[0041] However, for palladium-supported columns, the columns are generally thin and long (inner diameter less than 5 cm, length up to several meters or even longer), and often bent into U-shapes or paperclip shapes. Therefore, only granular packing can be used, and they cannot be pressed into blanks. Without pressing, the advantages of expanded graphite will be lost. After natural graphite is converted into expanded graphite, its density decreases, and its thermal conductivity also decreases significantly (from 129 W / m³). -1 K-1 Reduced to 10Wm -1 K -1 (See below). In its loosely packed state, its volume ratio is larger than that of metal foam, and its thermal conductivity is far inferior to that of metal foam.

[0042] Natural graphite refers to a natural product that exists on the Earth's surface.

[0043] Natural graphite has a small coefficient of thermal expansion (1×10⁻⁶). -6 -30×10 -6 K (which does not produce volume change during thermal cycling), high thermal conductivity, high temperature resistance and ultra-high lubricity (friction coefficient 0.08-0.16), high plasticity, high chemical stability and radiation resistance (especially important for tritium separation) make it very suitable for thermal cycling adsorption.

[0044] In some embodiments, natural graphite includes at least one of natural flake graphite, amorphous graphite, and bulk graphite. That is, the filler material can be one of natural flake graphite, amorphous graphite, and bulk graphite, or two of these three types, or it can simultaneously include all three. In this application, natural flake graphite is used as an example for illustration in the embodiments.

[0045] Hydrogen storage materials exhibit hydrogen isotope effects, thus enabling their use in chromatographic columns for the separation of hydrogen isotopes.

[0046] In some embodiments, the hydrogen storage material includes at least one of pure palladium powder, palladium-diatomite, palladium-molecular sieve, and palladium-α-alumina. That is, the hydrogen storage material can be one of pure palladium powder, palladium-diatomite, palladium-molecular sieve, and palladium-α-alumina; it can be two of these materials; it can be three of these materials; or it can simultaneously include pure palladium powder, palladium-diatomite, palladium-molecular sieve, and palladium-α-alumina. In this application, palladium-diatomite is used as an example of a hydrogen storage material for illustration.

[0047] The packing material provided in this application embodiment is used for the separation of hydrogen isotopes by thermal cycling adsorption. The packing material includes a hydrogen storage material with hydrogen isotope effect and natural graphite, which are uniformly mixed. By setting the packing material to include a hydrogen storage material with hydrogen isotope effect and natural graphite, the thermal conductivity of the packing material is improved. The thermal conductivity of natural graphite is more than an order of magnitude greater than that of expanded graphite, and its density is 150-300 times greater than that of expanded graphite. Therefore, under the premise of a certain mass, the volume occupied by the packing material is smaller, and the corresponding hydrogen adsorption capacity is higher, resulting in better hydrogen isotope separation efficiency. In other words, by using natural graphite as a thermal conductivity enhancer, the thermal conductivity of the packing material is improved while minimizing the impact on the saturated hydrogen adsorption capacity. In addition, natural graphite is soft and highly lubricating, and its flowability is better than that of metal foam and hydrogen storage material when packed, making it easier to fill the voids in the chromatographic column, which is beneficial to the preparation of the chromatographic column.

[0048] The present application also provides a filling material for separating hydrogen isotopes by thermal cycling adsorption. The filling material includes a hydrogen storage material with hydrogen isotope effect and natural graphite, and the hydrogen storage material and natural graphite are uniformly mixed.

[0049] This application provides a chromatographic column for separating hydrogen isotopes using a thermal cycling adsorption method. The chromatographic column includes a container and a packing material provided in any embodiment of this application, with the packing material disposed inside the container.

[0050] The containers are thin and long (with an inner diameter of less than 5cm and a length of several meters or even longer), and are often bent into a U-shape or paperclip shape.

[0051] By using a packing material that includes hydrogen storage materials with hydrogen isotope effects and natural graphite, the thermal conductivity of the packing material is improved. Natural graphite has a thermal conductivity more than an order of magnitude higher than expanded graphite, and its density is 150-300 times greater. Therefore, given a fixed mass, it occupies a smaller volume of packing material, resulting in higher hydrogen adsorption and better hydrogen isotope separation efficiency. In other words, by using natural graphite as a thermal conductivity enhancer, the thermal conductivity of the packing material is improved while minimizing its impact on saturated hydrogen adsorption. Furthermore, natural graphite is soft and highly lubricating, exhibiting better flowability than metal foam and hydrogen storage materials when packed, making it easier to fill the voids within the chromatographic column, which is beneficial for column preparation.

[0052] This application also provides a method for preparing a chromatographic column. The chromatographic column is used for the separation of hydrogen isotopes by thermal cycling adsorption. The chromatographic column includes a container and the packing material described in any embodiment of this application. The packing material is disposed inside the container. Please refer to [link to relevant documentation]. Figure 2 The preparation methods include:

[0053] S1: Mix hydrogen storage material and natural graphite in a certain proportion and stir evenly to obtain the filling material;

[0054] S2: Fill the container with the filler material;

[0055] S3: Compact the filler material inside the container.

[0056] It should be noted that the mixing in this embodiment is done manually, with each type of mixture using roughly the same mixing method and force, and for the same mixing time. Filling is also done manually, as is the compaction process, with the vibration method and force being roughly the same, and the vibration time being the same. In practice, suitable mixing, filling, and compaction devices can be selected, which may result in more stable and superior performance of the mixed materials.

[0057] In some embodiments, the particle size of natural graphite is 20-40 mesh. For example, 20 mesh, 22 mesh, 24 mesh, 25 mesh, 27 mesh, 28 mesh, 30 mesh, 33 mesh, 35 mesh, 37 mesh, 38 mesh, 39 mesh, 40 mesh, etc.

[0058] By setting the particle size of natural graphite to 20-40 mesh, natural graphite within this particle size range has better thermal conductivity, better fluidity, and is more likely to fill the voids in the column.

[0059] In some embodiments, the particle size of natural graphite is 380 μm-830 μm. For example, it is 380 μm, 390 μm, 400 μm, 430 μm, 450 μm, 470 μm, 480 μm, 500 μm, 520 μm, 530 μm, 580 μm, 600 μm, 620 μm, 640 μm, 660 μm, 670 μm, 700 μm, 740 μm, 750 μm, 790 μm, 800 μm, or 830 μm, etc.

[0060] By setting the particle size of natural graphite to 380μm-830μm, natural graphite within this particle size range has better thermal conductivity, better fluidity, and is more likely to fill the voids in the column.

[0061] In some embodiments, the palladium weight percentage in the palladium-diatomite is 40wt%-70wt%. For example, it is 40wt%, 42wt%, 43wt%, 45wt%, 47wt%, 50wt%, 53wt%, 54wt%, 58wt%, 60wt%, 63wt%, 65wt%, 68wt%, or 70wt%, etc.

[0062] In some embodiments, the particle size of the hydrogen storage material is 0.1 mm to 1 mm. For example, it is 0.1 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.42 mm, 5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.9 mm, or 1 mm, etc.

[0063] For example, palladium-diatomaceous earth particles with a palladium content of 54 wt% and a particle size of 0.25-0.42 mm, and 20-40 mesh natural flake graphite (99.99% purity) can be selected. The palladium-diatomaceous earth (palladium content of 54 wt%) is mixed with a certain proportion of aluminum foam (density of 0.178 g / cc) or natural flake graphite, stirred evenly, and then packed into a container with an inner diameter of 4.76 cm for chromatography. The mixture is then fully compacted, and the density of palladium content is measured and calculated.

[0064] In one specific embodiment, five chromatographic columns containing different components are configured with varying effective thermal conductivity. These are chromatographic columns 1, 2, 3, 4, and 5. The inner diameter of all five columns is 4.76 cm. The thermally conductive material, palladium density, and effective thermal conductivity of the packing materials in columns 1, 2, 3, 4, and 5 are shown in Table 2 below.

[0065] It should be noted that the mixing of columns 1, 2, 3, 4, and 5 was done manually, with each mixture using roughly the same mixing method, force, and time. Packing was also done manually, as was the compaction process, with similar vibration methods, forces, and durations. However, using appropriate mixing, packing, and compaction devices could potentially result in more stable and superior performance of the mixed packing.

[0066] The specific method for measuring effective thermal conductivity is not limited here. For example, the effective thermal conductivity of palladium-diatomaceous earth, palladium-diatomaceous earth with 3 wt% aluminum foam, palladium-diatomaceous earth with 0.2 wt% natural flake graphite, palladium-diatomaceous earth with 0.5 wt% natural flake graphite, and palladium-diatomaceous earth with 1 wt% natural flake graphite were measured using a self-purchased Hot Disk TPS1500 dynamic thermal conductivity testing device. The mixed fillers were also manually stirred and compacted to achieve uniform mixing.

[0067] Table 2 Comparison of effective thermal conductivity of chromatographic columns containing different components

[0068] chromatographic column Inner diameter(cm) thermal conductive materials Palladium density (g / cc) <![CDATA[Effective thermal conductivity (Wm -1 K -1 )]]> 1 4.76 none 0.66 0.031 2 4.76 3wt% aluminum foam 0.53 1.022 3 4.76 0.2wt% natural graphite 0.64 0.854 4 4.76 0.5wt% natural graphite 0.61 1.095 5 4.76 1 wt% natural graphite 0.55 1.582

[0069] The measurement results in Table 2 show that adding aluminum foam and natural graphite to palladium-diatomite can significantly improve the effective thermal conductivity. Natural graphite, due to its light weight, softness, and strong lubrication, has a much smaller volume and mass ratio than aluminum foam when achieving the same thermal conductivity. Thus, a significant improvement in effective thermal conductivity can be achieved without increasing its own weight or significantly reducing the density of the effective component palladium.

[0070] While the addition of natural graphite effectively improves thermal conductivity, will it adversely affect the hydrogen absorption capacity and rate of palladium-diatomite during actual hydrogen absorption? Figure 1 The figure shows the hydrogen pressure change curves over time for chromatographic columns of the five different packed materials (which were also manually stirred, mixed, and tapped) at an initial hydrogen pressure of 300 kPa when the packed materials were saturated with hydrogen absorption.

[0071] Understandably, the steeper the curve (the greater the slope), the faster it reaches the plateau region, indicating a faster reaction rate, which corresponds to a shorter single thermal cycle time and better separation efficiency; the lower the pressure corresponding to the plateau region of the curve, the higher the hydrogen absorption capacity, and the better the separation efficiency.

[0072] Please see Figure 1 The hydrogen absorption rate of pure palladium support is relatively slow. Adding natural graphite and aluminum foam significantly accelerates the absorption rate. The addition of aluminum foam results in a relatively larger increase in absorption rate, but also reduces the saturated hydrogen absorption capacity by approximately 3.27%. Adding 0.2 wt% natural graphite has almost no effect on the saturated hydrogen absorption capacity, while adding 0.5 wt% reduces it by approximately 0.77%. Adding 1 wt% natural graphite results in a similar absorption rate to pure palladium support, but reduces the saturated hydrogen absorption capacity by approximately 2.61%.

[0073] Therefore, it can be seen that the palladium (Pd) content of the filler material decreases to varying degrees and the effective thermal conductivity increases to varying degrees after adding 0.2wt%-1wt% of natural flake graphite and 3wt% of aluminum foam. Considering the combined effects on hydrogen absorption rate and saturated hydrogen absorption capacity, it can be seen that adding 0.2wt%-0.5wt% of natural flake graphite significantly improves the hydrogen absorption rate and effective thermal conductivity while hardly reducing the saturated hydrogen absorption capacity and the palladium density of the filler material. However, when the content of natural flake graphite is further increased, the volume occupancy rate also increases, leading to a decrease in the palladium density of the filler material. Furthermore, with the increase in the proportion of flake graphite, its covering effect on palladium and the increase in gas resistance (graphite itself is not loose and porous) become more obvious, thus reducing the reaction rate and offsetting the beneficial effect of increased thermal conductivity.

[0074] In some embodiments, the weight percentage of natural graphite is less than or equal to 1 wt%. For example, it is 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.35 wt%, 0.5 wt%, 0.55 wt%, 0.6 wt%, 0.65 wt%, 0.7 wt%, 0.75 wt%, 0.8 wt%, 0.85 wt%, 0.9 wt%, 0.95 wt%, or 1 wt%, etc.

[0075] Within this range, the weight percentage of natural graphite can improve the hydrogen absorption rate and effective thermal conductivity, while minimizing the reduction in its saturated hydrogen absorption capacity and the palladium density of the filler material.

[0076] In some embodiments, the weight percentage of natural graphite is 0.2wt%-0.5wt%. For example, it is 0.2wt%, 0.25wt%, 0.3wt%, 0.35wt%, 0.4wt%, 0.45wt%, or 0.5wt%, etc.

[0077] Within this range, the weight percentage of natural graphite significantly improves the hydrogen absorption rate and effective thermal conductivity while almost not reducing its saturated hydrogen absorption capacity and the palladium density of the filler material.

[0078] In the description of this application, the references to terms such as "in one embodiment," "in some embodiments," "in other embodiments," "in yet another embodiment," or "exemplary," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine the different embodiments or examples described in this application, as well as the features of the different embodiments or examples.

[0079] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A method for preparing a chromatographic column, characterized in that, The chromatographic column includes a container and a packing material, the packing material being disposed within the container. The filling material is used for separating hydrogen isotopes by thermal cycling adsorption. The filling material includes a hydrogen storage material with hydrogen isotope effect and natural graphite, wherein the hydrogen storage material and the natural graphite are uniformly mixed; the particle size of the natural graphite is 20-40 mesh; the weight percentage of the natural graphite is 0.2wt%-0.5wt%; the hydrogen storage material includes at least one of pure palladium powder, palladium-diatomite, palladium-molecular sieve, and palladium-α-alumina. The method for preparing the chromatographic column includes: The hydrogen storage material and natural graphite are mixed in a certain proportion and stirred evenly to obtain the filler material; The filler material is filled into the container; The filling material is compacted inside the container.

2. The method for preparing the chromatographic column according to claim 1, characterized in that, The natural graphite includes at least one of natural flake graphite, amorphous graphite, and massive graphite.

3. The method for preparing the chromatographic column according to claim 1, characterized in that, The hydrogen storage material is palladium-diatomite, wherein the weight percentage of palladium in the palladium-diatomite is 40wt%-70wt%.

4. The method for preparing the chromatographic column according to claim 1, characterized in that, The particle size of the hydrogen storage material is 0.1 mm to 1 mm.

5. A chromatographic column, characterized in that, The chromatographic column is prepared by the method described in claim 1.

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