Method for separating impurities in liquid phase and application

Abstract

The invention relates to the field of impurity separation, and discloses a method for separating impurities in a liquid phase and application, the method comprises the following steps: (1) contacting a liquid-phase raw material with an adsorbent for adsorption to obtain a liquid-phase material flow; the liquid-phase raw material comprises an organic liquid hydrogen storage substance and impurities; the adsorbent preferentially adsorbs impurities in the liquid-phase raw material; (2) carrying out back-flushing desorption on the adsorbent by using part of the liquid-phase material flow to obtain a desorption solution; based on the total mass of the desorption solution, the impurity content in the desorption solution is 2-5%; (3) feeding the desorption liquid into a rectifying tower, carrying out rectification separation, and outputting the obtained tower bottom distillate and the residual part of liquid phase material flow as products; and (4) regenerating the adsorbent after backwashing desorption. The method has the characteristics of high purity of the organic liquid hydrogen storage substance, low cost and no introduction of new impurities.

Description

Technical Field

[0001] This invention relates to the field of impurity separation, and specifically to a method and application for separating impurities in a liquid phase. Background Technology

[0002] In the global energy transition, hydrogen energy, with its clean, efficient, and sustainable characteristics, is considered an important component of the future energy system. However, due to challenges in storage and transportation, including high costs, technical difficulties, and safety concerns, hydrogen storage and transportation have remained a technological bottleneck hindering its widespread application. Organic liquid hydrogen storage (LOHC) technology, as an innovative solution, offers new insights into addressing the challenges of traditional hydrogen storage technologies due to its advantages such as high-density storage, safety, stability, and environmental friendliness.

[0003] Organic liquid hydrogen storage technology utilizes specific unsaturated organic compounds as hydrogen storage carriers. Through a hydrogenation reaction, hydrogen is stored in the liquid organic matter in the form of chemical bonds, forming a hydrogen-storing organic liquid that can be stably stored at room temperature and pressure. This technology not only significantly increases the storage density of hydrogen, allowing it to store more energy in a smaller volume, but also greatly reduces safety risks during storage and transportation because the organic liquid is stable at room temperature and pressure. It is suitable for various scenarios, including stationary large-scale hydrogen storage, hydrogen supply for fuel cell vehicles, distributed energy storage, international hydrogen supply chains, and long-distance hydrogen transportation. Furthermore, this technology is environmentally friendly; the byproducts generated during the hydrogenation and dehydrogenation reactions are typically harmless or easily processed substances, with minimal environmental impact.

[0004] However, despite the numerous advantages of organic liquid hydrogen storage technology, several challenges remain in practical applications. Among these, the impurity content in the organic hydrogen storage liquid is a key factor affecting its hydrogen storage performance and safety. With the increase in the number of hydrogen addition and dehydrogenation reaction cycles, cracking product impurities in the liquid hydrogen storage material continuously accumulate. The presence of excessive impurities not only reduces the system's effective hydrogen storage rate but also generates carbon deposits on the catalyst surface, leading to increased bed pressure drop and even affecting the stability of the entire hydrogen storage-dehydrogenation cycle. Furthermore, impurities can adversely affect the long-term storage and transportation of the organic hydrogen storage liquid, increasing system maintenance costs and safety risks.

[0005] Therefore, there is an urgent need to develop an efficient method for impurity separation. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of low purity, high cost, and easy introduction of new impurities in existing organic liquid hydrogen storage materials, and to provide a method and application for impurity separation in the liquid phase. This method has the characteristics of high purity, low cost, and no introduction of new impurities in organic liquid hydrogen storage materials.

[0007] To achieve the above objectives, a first aspect of the present invention provides a method for separating impurities in a liquid phase, wherein the method includes: (1) The liquid raw material is contacted with the adsorbent for adsorption to obtain a liquid stream; The liquid-phase feedstock includes organic liquid hydrogen storage materials and impurities; The adsorbent preferentially adsorbs impurities in the liquid phase raw material; (2) A portion of the liquid phase stream is backflushed to desorb the adsorbent, resulting in a desorbed solution; Based on the total mass of the desorption solution, the impurity content in the desorption solution is 2-5%; (3) The desorbed liquid is fed into a distillation column for distillation separation, and the bottom distillate and the remaining liquid phase stream are output as products. (4) Regenerate the adsorbent after backflushing and desorption.

[0008] Preferably, the flow ratio of the partial liquid phase stream to the remaining liquid phase stream is 1:2-5.

[0009] The second aspect of the present invention provides the application of the method described in the first aspect in an organic liquid circulating hydrogen storage and release system.

[0010] Compared with existing technologies, the present invention has the following beneficial effects through the above technical solution: The innovative impurity treatment technology for liquid-phase feedstocks proposed in this invention first enriches impurities to improve separation efficiency, reduces the throughput, number of trays, and heat load of the distillation column, and maintains high-efficiency separation while significantly reducing energy consumption. Compared with direct distillation, this technology significantly improves the economic efficiency and environmental friendliness of impurity separation in liquid-phase feedstocks. By splitting the liquid stream obtained during adsorption into two streams, one stream is used as a flushing agent to directly backflush and desorb the adsorbent. This not only greatly reduces the raw material cost of the process, but more importantly, it avoids the introduction of other impurities and saves subsequent separation costs. Attached Figure Description

[0011] Figure 1 This is a process flow diagram showing that the bottom distillate does not need to be recirculated back into the adsorption tower for adsorption. Figure 2 The process flow diagram shows the bottom distillate that needs to be recycled back into the adsorption tower for adsorption. Figure 3 This is a schematic diagram illustrating the application of the method of the present invention in an organic liquid circulating hydrogen storage and release system.

[0012] Explanation of reference numerals in the attached figures Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this invention are based on weight, unless being based on weight would not be in accordance with the common understanding of those skilled in the art.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the invention, are intended to cover non-exclusive inclusion.

[0016] In this invention, unless otherwise specified, "first," "second," and "third" do not indicate a sequential order, nor do they limit the specific materials or steps; they are merely used to distinguish between different materials or steps. For example, in "first adsorption tower," "second adsorption tower," and "third adsorption tower," "first," "second," and "third" are used only to indicate that these are not the same adsorption tower; similarly, in "first heat exchanger," "second heat exchanger," and "third heat exchanger," "first," "second," and "third" are used only to indicate that these are not the same heat exchanger; in "first heat exchange" and "second heat exchange," "first" and "second" are used only to indicate that these are not the same heat exchanger; in "first regeneration treatment" and "second regeneration treatment," "first" and "second" are used only to indicate that these are not the same regeneration treatment.

[0017] In this invention, a balance gas is used to control the pressure during the separation of impurities in the liquid phase. The balance gas can be nitrogen and / or argon.

[0018] The present invention does not particularly limit the method of controlling the temperature during the separation of impurities in the liquid phase. For example, heat can be extracted by the built-in coil of the adsorption tower.

[0019] The present invention does not particularly limit the medium for controlling the temperature during the separation of impurities in the liquid phase. For example, it can be at least one of water, ethylene glycol and heat transfer oil.

[0020] A first aspect of the present invention provides a method for separating impurities in a liquid phase, wherein the method includes: (1) The liquid raw material is contacted with the adsorbent for adsorption to obtain a liquid stream; The liquid-phase feedstock includes organic liquid hydrogen storage materials and impurities; The adsorbent preferentially adsorbs impurities in the liquid phase raw material; (2) A portion of the liquid phase stream is backflushed to desorb the adsorbent, resulting in a desorbed solution; Based on the total mass of the desorption solution, the impurity content in the desorption solution is 2-5%; (3) The desorbed liquid is fed into a distillation column for distillation separation, and the bottom distillate and the remaining liquid phase stream are output as products. (4) Regenerate the adsorbent after backflushing and desorption.

[0021] The inventors of this invention discovered that, within the framework of traditional adsorption-desorption processes, the desorption process typically uses a solvent with high solubility in the target substance as a rinsing agent. After the desorption step, further effective separation of the solvent and the target substance is required. However, this process inevitably leads to solvent residue in the target substance, thus affecting its performance in subsequent chemical production. This invention innovatively proposes first separating impurities from the liquid-phase feedstock to obtain a liquid stream. A portion of this liquid stream is then used as a rinsing agent to backflush and desorb the adsorbent containing impurities. This process enriches the impurities and avoids introducing other impurities during the separation process. If other impurities are introduced and accumulate over a long period, they need to be sent to a hydrogen storage regeneration plant to be converted back into feedstock. Therefore, this invention not only significantly reduces the raw material cost of the process but, more importantly, saves on subsequent separation costs. Furthermore, it innovatively proposes enriching impurities first to improve separation efficiency, achieving highly efficient impurity removal, improving separation efficiency, reducing distillation column throughput, number of trays, and heat load, maintaining high-efficiency separation while significantly reducing energy consumption. Compared with direct distillation, this technology significantly improves the economics and environmental friendliness of organic liquid hydrogen storage technology.

[0022] The organic liquid hydrogen storage material described in this invention has the conventional meaning in the art. Preferably, the organic liquid hydrogen storage material refers to N-alkylcarbazole substances and mixtures thereof or indole substances and mixtures thereof.

[0023] Furthermore, preferably, the hydrogen storage rate of the organic liquid hydrogen storage material is 85-100 wt%, based on the theoretical maximum hydrogen storage capacity of hydrogen in the hydrogen storage material.

[0024] In this invention, hydrogen storage rate = actual hydrogen storage mass / theoretical hydrogen storage mass.

[0025] The present invention allows for a wide range of choices regarding the flow direction of the liquid phase stream during backflushing desorption. For example, it can be the same as or opposite to the flow direction of the stream during adsorption. Preferably, during backflushing desorption, the flow direction of the liquid phase stream is opposite to that during adsorption, which is more conducive to washing away impurities on the adsorbent and thus achieving the enrichment of impurities.

[0026] The present invention has a wide range of choices for liquid phase raw materials. Preferably, the liquid phase raw materials are selected from hydrogenated N-alkylcarbazole and / or hydrogenated alkyl-substituted indole, and more preferably hydrogenated N-alkylcarbazole.

[0027] The present invention does not particularly limit the source of the liquid phase raw material. For example, the liquid phase raw material can come from the circulating working fluid of an organic liquid hydrogen storage device.

[0028] The present invention has a wide range of choices for N-alkylcarbazoles. Preferably, the N-alkylcarbazole is selected from at least one of N-methylcarbazole, N-propylcarbazole, N-ethylcarbazole, N-butylcarbazole, and N-isopropylcarbazole.

[0029] The present invention has a wide range of choices for alkyl-substituted indoles. Preferably, the alkyl-substituted indoles are selected from at least one of N-methylindole, N-ethylindole, 2-methylindole, 7-ethylindole and 2,3-dimethylindole.

[0030] The present invention has a wide range of choices for the types of impurities. Preferably, the impurities are selected from the pyrolysis products of liquid-phase raw materials, and more preferably at least one of carbazole, 4H-carbazole, 8H-carbazole and 12H-carbazole, indole, 2H-indole and 4H-indole.

[0031] According to the present invention, preferably, the impurity content is 0.5-1 wt% based on the total mass of the liquid phase raw material, more preferably 0.6-0.8 wt%.

[0032] According to the present invention, preferably, the content of impurities in the liquid phase stream is ≤0.01wt% based on the total mass of the liquid phase stream.

[0033] The present invention does not have a particular limitation on the number of adsorption cycles, as long as the content of impurities in the liquid phase stream is ≤0.01wt%. Those skilled in the art can select according to actual needs.

[0034] This invention uses gas chromatography to determine the content of impurities in a liquid stream.

[0035] According to the present invention, preferably, the amount of adsorbent used is 5-10 v / v of the liquid phase raw material.

[0036] This invention allows for a wide range of adsorbent selection. Preferably, the adsorbent is selected from at least one of γ-alumina, Beta molecular sieve, mordenite, Y molecular sieve, and activated carbon. Using the above-mentioned adsorbent can improve the adsorption capacity, and it can also selectively adsorb impurities by utilizing their alkalinity, exhibiting weak interaction with the liquid phase. Preferably, it is selected from at least one of γ-alumina, Beta molecular sieve, mordenite, and Y molecular sieve.

[0037] In this invention, "v / v%" means the ratio of the volume of adsorbent used to the volume of liquid raw material used.

[0038] This invention allows for a wide selection range of specific surface areas for the adsorbent; preferably, the specific surface area of ​​the adsorbent is greater than 500 m². 2 / g.

[0039] The present invention does not have a particular limitation on the shape of the adsorbent, as long as it can fully adsorb. Preferably, the adsorbent is spherical or columnar.

[0040] According to the present invention, preferably, the adsorption conditions in step (1) include: a temperature of 50-150°C, more preferably 100-150°C; a pressure of 5-20 bar, more preferably 5-15 bar; and a time of 3-9 h, more preferably 3-6 h. Using the above adsorption conditions reduces energy consumption, improves the adsorption capacity and selectivity of the adsorbent for impurities, reduces the impurity content in the purified liquid stream, reduces the burden on the subsequent distillation column, lowers the impurity content in the bottom distillate, and ensures that adsorption can still be completed even when the impurity content in the hydrogen storage liquid is low.

[0041] According to the present invention, preferably, step (2) further includes performing a first heat exchange on a portion of the liquid phase stream, and then backflushing and desorbing the adsorbent.

[0042] The present invention has a wide range of temperature selection for the first heat exchange, as long as it can meet the requirements of the present invention. Preferably, the first heat exchange temperature is the same as the temperature of the isothermal stage of backflushing desorption.

[0043] The present invention allows for a wide range of selection for the flow ratio of the partial liquid phase stream to the remaining liquid phase stream. Preferably, the flow ratio of the partial liquid phase stream to the remaining liquid phase stream is 1:2-5, and more preferably, it is 1:2-3.

[0044] In this invention, the rinsing agent for the next process can be produced on the premise of ensuring that the liquid raw material is purified. By adopting the above-mentioned flow ratio, the feed amount of the distillation column is more suitable, which is more conducive to enriching impurities, improving separation efficiency, and greatly reducing the operating cost of the adsorption-desorption process.

[0045] The present invention offers a wide range of options for the ratio of operating time between the heating stage and the isothermal stage. Preferably, the backflushing desorption in step (2) includes both a heating stage and an isothermal stage, with the ratio of operating time between the heating stage and the isothermal stage being 1:9-30, more preferably 1:9-19. In this invention, the rapid temperature rise from a low temperature to an isothermal temperature is more conducive to the effective desorption of impurities, reducing the throughput of the distillation column and improving the separation effect.

[0046] According to the present invention, preferably, the conditions for backflushing desorption in step (2) include: the temperature of the isothermal stage is 200-350°C, the adsorption intensity of impurities on the adsorbent is reduced, the impurities can be effectively desorbed and enriched, and more preferably 200-300°C. According to the present invention, preferably, the conditions for backflushing desorption in step (2) include: a pressure of 5-20 bar, more preferably 10-20 bar; According to the present invention, preferably, the conditions for backflushing and desorption in step (2) include: a time of 3-9 hours, more preferably 3-6 hours.

[0047] In this invention, using the above-mentioned preferred range is more conducive to enriching impurities and improving the separation efficiency of impurities.

[0048] The invention also includes subjecting the desorbed liquid to a second heat exchange before feeding it into the distillation column.

[0049] The present invention does not particularly limit the temperature of the second heat exchange, as long as the desorbed liquid becomes a saturated liquid that is just not vaporized. Those skilled in the art can select the appropriate temperature according to actual needs.

[0050] The present invention has a wide range of distillation methods. Those skilled in the art can select a suitable separation method according to the type of hydrogen storage material, the type of impurities and the level of impurity content. Preferably, the distillation in step (3) is selected from atmospheric distillation and / or vacuum distillation.

[0051] The atmospheric distillation described in this invention refers to the distillation operation carried out in a distillation column under conditions close to atmospheric pressure.

[0052] The vacuum distillation described in this invention refers to the distillation operation carried out in a distillation column under conditions below atmospheric pressure.

[0053] This invention offers a wide range of heating methods for distillation. Preferably, the distillation is heated by medium-pressure steam, with the medium pressure ranging from 15 to 20 bar. Adopting this preferred range helps improve thermal efficiency and reduce the energy consumption of the distillation column.

[0054] According to the present invention, preferably, the conditions for the distillation separation include: a column top pressure of 0.3-1 bar, more preferably 0.5-1 bar.

[0055] According to the present invention, preferably, the conditions for the distillation separation include: a column top temperature of 150-300°C, more preferably 240-280°C.

[0056] According to the present invention, preferably, the content of impurities in the bottom distillate is ≤0.1wt%, more preferably ≤0.06wt%, based on the total mass of the bottom distillate.

[0057] This invention uses gas chromatography to test the content of impurities in the bottom distillate of a column.

[0058] In this invention, depending on actual needs, when the impurity content in the bottom distillate does not meet production requirements, the obtained bottom distillate is further subjected to impurity separation using the method provided in this invention, such as... Figure 2 As shown.

[0059] Compared to traditional direct distillation, the distillation method in this invention first enriches the hydrogen storage material with low-concentration impurities before distillation separation. This not only significantly improves separation efficiency and product purity but also substantially reduces energy consumption and production costs.

[0060] It should be noted that in the distillation operation of the present invention, light component impurities are distilled from the top of the distillation column, and the liquid phase stream after impurity separation is output from the bottom of the column.

[0061] According to the present invention, preferably, the regeneration in step (4) includes performing a first regeneration process and a second regeneration process in sequence, wherein the temperature of the first regeneration process is higher than that of the second regeneration process, and the pressure of the first regeneration process is lower than that of the second regeneration process.

[0062] In this invention, the first regeneration process aims to remove the liquid holding capacity of the adsorbent, and the second regeneration process aims to restore the adsorption tower to its initial state.

[0063] In this invention, the initial state refers to the adsorption tower being used in the next cycle to adsorb impurities in the liquid raw material during continuous operation, and being able to effectively perform the adsorption function.

[0064] According to the present invention, preferably, the conditions for the first regeneration treatment include a temperature of 200-350°C, more preferably 200-300°C.

[0065] According to the present invention, preferably, the conditions for the first regeneration treatment include a pressure of 0.1-0.5 bar, more preferably 0.2-0.5 bar.

[0066] According to the present invention, preferably, the conditions for the first regeneration treatment include a time of 3-9 hours, more preferably 3-6 hours.

[0067] In this invention, a low-pressure process is used in the adsorbent regeneration process. This innovative method can significantly reduce the liquid holding capacity of the adsorbent, reduce its contact time with the liquid hydrogen storage material, fully carry out liquid holding desorption, and thus effectively extend the service life of the adsorbent and reduce the maintenance cost of the system.

[0068] According to the present invention, preferably, the conditions for the second regeneration process include a temperature of 50-150°C, more preferably 100-150°C.

[0069] According to the present invention, preferably, the conditions for the second regeneration treatment include a pressure of 5-20 bar, more preferably 5-15 bar.

[0070] According to the present invention, preferably, the temperature of the first regeneration treatment is 100-250°C higher than that of the second regeneration treatment.

[0071] According to the present invention, preferably, the pressure of the first regeneration treatment is 4.8-19.5 bar lower than that of the second regeneration treatment.

[0072] According to the present invention, preferably, the time ratio of the first regeneration treatment and the second regeneration treatment is 3-10:1, more preferably 4-9:1.

[0073] In this invention, during the regeneration process, using appropriate pressure and temperature can ensure that the liquid holdup of the adsorbent is reduced to a sufficiently low level, thereby reducing the contact time between the adsorbent and the material and maximizing the catalyst life. However, excessive pressure reduction or excessively high temperature will lead to a decrease in energy utilization and an increase in process energy consumption.

[0074] According to the present invention, preferably, the adsorption time in step (1), the backflushing desorption time in step (2), and the regeneration time in step (3) are the same.

[0075] Using the above regeneration conditions is more conducive to restoring the adsorption tower to its initial state and to effectively performing the adsorption function in the next cycle.

[0076] According to the present invention, preferably, the method is carried out in a separation system comprising at least three adsorption towers, each adsorption tower being filled with an adsorbent that preferentially adsorbs impurities in the liquid phase feedstock.

[0077] According to the present invention, preferably, in the continuous operation of the method, at least one adsorption tower performs adsorption, at least one adsorption tower performs desorption, and at least one adsorption tower performs regeneration.

[0078] According to the present invention, preferably, the system includes a first adsorption tower, a second adsorption tower, and a third adsorption tower; During continuous operation, the liquid feedstock is fed into the first adsorption tower for adsorption. After the first heat exchange is performed using a portion of the liquid stream, the adsorbent in the second adsorption tower is backflushed and desorbed to obtain the desorbed liquid. The desorbed liquid is fed into a distillation tower for distillation separation. The bottom distillate and the remaining liquid stream are output as products. The third adsorption tower is then regenerated. After adsorption is complete, the liquid feedstock is sent to the third adsorption tower for adsorption. A portion of the liquid stream is used to backflush and desorb the adsorbent in the first adsorption tower to obtain the desorbed liquid. After passing through the second heat exchange, the desorbed liquid is sent to the distillation tower for distillation separation. The bottom distillate and the remaining liquid stream are output as products. The second adsorption tower is regenerated. The above process is repeated, and the three adsorption towers operate in an alternating cycle.

[0079] The cyclical alternation operation described in this invention refers to the situation where, while one adsorption tower is performing adsorption, the other two towers are performing backflushing desorption and regeneration, respectively. Each adsorption tower completes three full-process operations (adsorption, backflushing desorption, and regeneration) as one operating cycle. For example, within one cycle, the operating states of the three adsorption towers are as follows: First adsorption tower (Q1: adsorption, Q2: backflushing desorption, Q3: regeneration); Second adsorption tower (Q1: backflushing desorption, Q2: regeneration, Q3: adsorption); The third adsorption tower (Q1: regeneration, Q2: adsorption, Q3: backflushing desorption). To further explain, while the first adsorption tower is performing adsorption, the second adsorption tower is performing backflushing desorption, and the third adsorption tower is performing regeneration. After the first adsorption tower completes adsorption, the liquid-phase feedstock is switched to the third adsorption tower for adsorption, while the first adsorption tower performs backflushing desorption and the second adsorption tower is regenerated. After the third adsorption tower completes adsorption, the liquid-phase feedstock is switched to the second adsorption tower for adsorption, while the third adsorption tower performs backflushing desorption and the first adsorption tower is regenerated. The completion of the above operations is considered as one cycle.

[0080] According to some preferred embodiments of the present invention, the method includes: The liquid feedstock is fed into the first adsorption tower and comes into contact with the adsorbent for the first adsorption. After the first adsorption is completed, the liquid feedstock is switched to the second adsorption tower for the second adsorption. A portion of the liquid stream obtained from the second adsorption is used to backwash and desorb the adsorbent in the first adsorption tower to obtain a desorbed liquid. The desorbed liquid is sent to a distillation tower for distillation and separation. The bottom distillate and the remaining liquid stream are output as products. After the second adsorption is completed, the liquid feedstock is switched to the third adsorption tower for the third adsorption. A portion of the liquid stream from the third adsorption is used to backflush and desorb the adsorbent in the second adsorption tower to obtain a desorbed liquid. The desorbed liquid is sent to a distillation tower for distillation separation. The bottom distillate and the remaining liquid stream are output as products. The first adsorption tower is regenerated. After the third adsorption is completed, the liquid feedstock is switched to the first adsorption tower for the first adsorption. A portion of the liquid stream from the first adsorption is used to backflush and desorb the adsorbent in the third adsorption tower, yielding a desorbed liquid. The desorbed liquid is sent to a distillation tower for distillation separation, and the resulting bottom distillate and the remaining liquid stream are output as products. The second adsorption tower is then regenerated. This process is repeated, with the three adsorption towers operating in an alternating cycle to remove impurities from the liquid feedstock.

[0081] According to some specific embodiments of the present invention, such as Figure 1 As shown, during continuous operation, the liquid raw material is fed into the first adsorption tower 2 through the raw material feed pump 1. The adsorption temperature in the first adsorption tower 2 is controlled by the first heat exchanger 5. The raw material comes into contact with the adsorbent for the first adsorption. The liquid material is output as the product. After the first adsorption is completed, the liquid raw material is fed into the second adsorption tower 3 through the raw material feed pump 1. The adsorption temperature in the second adsorption tower 3 is controlled by the second heat exchanger 6. The second adsorption tower 3 performs the second adsorption to obtain a liquid stream. Part of the liquid stream is passed through the first heat exchanger 8 for heat exchange. The flushing agent feed pump 9 sends it into the first adsorption tower 2. The adsorption temperature in the first adsorption tower 2 is controlled by the first heat exchanger 5. The adsorbent in the first adsorption tower 2 is backflushed and desorbed to obtain a desorbed liquid. The desorbed liquid is fed through the desorbed liquid feed pump 10, passed through the second heat exchanger 11 for heat exchange, and sent into the distillation tower 12 for distillation separation. The bottom distillate and the remaining liquid stream are output as products. After the second adsorption is completed, the liquid raw material is fed into the third adsorption tower 4 through the raw material feed pump 1. The adsorption temperature in the third adsorption tower 4 is controlled by the third heat exchanger 7, and the adsorbent is contacted to carry out the third adsorption, resulting in a liquid stream. Part of the liquid stream is passed through the first heat exchanger 8 for heat exchange, and the flushing agent feed pump 9 sends it into the second adsorption tower 3. The adsorption temperature in the second adsorption tower 3 is controlled by the second heat exchanger 6, and the adsorbent in the second adsorption tower 3 is backflushed and desorbed to obtain a desorbed liquid. The desorbed liquid is passed through the desorbed liquid feed pump 10, passed through the second heat exchanger 11 for heat exchange, and sent into the distillation tower 12 for distillation separation. The bottom distillate and the remaining liquid stream are output as products. The first adsorption tower 2 is regenerated. After the third adsorption is completed, the liquid raw material is fed into the first adsorption tower 2 through the raw material feed pump 1. The adsorption temperature in the first adsorption tower 2 is controlled by the first heat exchanger 5, and the raw material comes into contact with the adsorbent for the first adsorption, resulting in a liquid stream. Part of the liquid stream is passed through the first heat exchanger 8 for heat exchange, and then sent to the third adsorption tower 4 through the flushing agent feed pump 9. The adsorption temperature in the third adsorption tower 4 is controlled by the third heat exchanger 7, and the adsorbent in the third adsorption tower 4 is backflushed and desorbed to obtain a desorbed liquid. The desorbed liquid is then passed through the desorbed liquid feed pump 10, through the second heat exchanger 11 for heat exchange, and then sent to the distillation tower 12 for distillation separation. The bottom distillate and the remaining liquid stream are output as products. The second adsorption tower 3 is then regenerated. The above process is repeated, with the three adsorption towers operating in an alternating cycle to remove impurities from the liquid raw material.

[0082] According to some specific embodiments of the present invention, such as Figure 2 As shown, during continuous operation, the operation and Figure 1 The method shown is the same, except that when the impurity content of the bottom distillate of the distillation column 12 does not meet the requirements, the bottom distillate of the distillation column 12 will be sent back to the adsorption column for impurity separation by the feed pump 1.

[0083] The second aspect of the present invention provides the application of the method described in the first aspect in an organic liquid circulating hydrogen storage and release system.

[0084] This invention is the first to apply the method described in the first aspect to a purification system for organic liquid hydrogen storage, achieving highly efficient impurity removal and effectively reducing the accumulation of decomposition products within the system. This provides strong support for improving the overall performance and reliability of organic liquid hydrogen storage technology, demonstrating its broad application prospects and potential in the hydrogen energy field. The technology provided by this invention ensures that impurities in the organic liquid hydrogen storage and release system remain at a low level, guaranteeing stable system operation and efficient hydrogen storage and release, and comprehensively improving the overall system efficiency and reliability.

[0085] According to some specific embodiments of the present invention, such as Figure 3 As shown, after hydrogen is introduced into the hydrogen storage system, it is then sent to the impurity removal system for impurity separation according to the method described in the first aspect, resulting in pure hydrogen storage material. The hydrogen storage material after impurity separation is then sent to the hydrogen release system, where hydrogen and the dehydrogenated hydrogen storage material are released (the material returns to its initial state). The released hydrogen storage material is returned to the hydrogen storage system through a circulation pipeline to participate in the next round of hydrogen storage, thus achieving material recycling. Meanwhile, impurities in the impurity removal system enter the regeneration system, where regenerated hydrogen storage material is separated and sent back to the circulation system to participate in the next round of hydrogen storage.

[0086] The present invention will be described in detail below through embodiments.

[0087] Unless otherwise specified, all examples and comparative examples below are conventional methods; the reagents, materials and instruments used are commercially available and / or prepared using methods known in the art, unless otherwise specified.

[0088] In the following comparative examples and embodiments, the methods for characterizing the content of impurities in the liquid stream and the content of impurities in the bottom distillate are as described above and will not be repeated here.

[0089] In the following examples and comparative examples, the states during continuous operation will be described in detail.

[0090] Example 1 In this embodiment, N2 is used to control the pressure during the separation of impurities in the liquid phase, and the adsorption tower has a built-in coil for heat extraction, with water as the heat extraction medium.

[0091] Specifically, such as Figure 1 As shown, N-propylcarbazole hydrogen storage material containing 0.8% of N-propylcarbazole (impurities from the cracking products of the liquid-phase feedstock, such as carbazole, dodecahydrocarbazole, octahydrocarbazole, and tetrahydrocarbazole) is introduced into the first adsorption tower 2 from the top via feed pump 1 for initial adsorption. The adsorption temperature in the first adsorption tower 2 is controlled by the first heat exchanger 5. The impurities are absorbed by Beta molecular sieves (specific surface area: 571.3 m²). 2 / g, adsorbent shape: strip) adsorption, operation time is 3 hours, to obtain liquid stream, the impurity content in the liquid stream is reduced to 56 ppm, and the liquid stream is output as product.

[0092] After the first adsorption is completed, N-propylcarbazole hydrogen storage material containing 0.8% of the pyrolysis product impurities (e.g., carbazole, dodecahydrocarbazole, octahydrocarbazole, tetrahydrocarbazole) of the liquid feed is introduced into the second adsorption tower 3 from the top of the second adsorption tower 3 for a second adsorption under conditions of 100°C and 15 bar. The adsorption temperature in the second adsorption tower 3 is controlled by the second heat exchanger 6. The impurities are adsorbed by the Beta molecular sieve. The operation time is 3 hours, and a liquid stream is obtained. The impurity content in the liquid stream is reduced to 56 ppm. Two-thirds of the liquid stream is output as product. One-third of the liquid stream is used as a flushing agent, which is heated by the first heat exchanger 8 at a temperature of 300°C. The flushing agent feed pump 9 enters the first adsorption tower 2 from the bottom for backflushing desorption. The adsorption temperature in the first adsorption tower 2 is controlled by the first heat exchanger 5. During backflushing desorption, the first adsorption tower 2 is first heated to 300°C within 18 minutes and maintained at a pressure of 15 bar. Then, the flushing agent enters the first adsorption tower 2 from the bottom and continues desorption for 162 minutes, resulting in a desorbed liquid with an impurity content of 5%. The desorbed liquid is fed through the desorbed liquid feed pump 10 and heated by the second heat exchanger 11 (becoming a saturated liquid). It is then fed into the distillation column 12 and heated under medium-pressure steam of 20 bar. Distillation separation is carried out under the conditions of a column top pressure of 1 bar and a column top temperature of 285°C. The impurity content of the bottom distillate is 86 ppm. The obtained bottom distillate and the remaining liquid stream are output as products. After the second adsorption is completed, N-propylcarbazole hydrogen storage material containing 0.8% of the pyrolysis product impurities (e.g., carbazole, dodecahydrocarbazole, octahydrocarbazole, tetrahydrocarbazole) from the liquid phase feedstock is introduced into the third adsorption tower 4 from the top of the third adsorption tower 4 for the third adsorption under conditions of 100°C and 15 bar. The adsorption temperature in the third adsorption tower 4 is controlled by the third heat exchanger 7. The impurities are adsorbed by the Beta molecular sieve. The operation time is 3 hours, resulting in a liquid stream with the impurity content reduced to 56 ppm. Two-thirds of the liquid stream is output as product. One-third of the liquid phase stream is used as a flushing agent, which is heated by the first heat exchanger 8 at a temperature of 300°C. The flushing agent feed pump 9 enters the second adsorption tower 3 from the bottom of the tower for backflushing desorption. The adsorption temperature in the second adsorption tower 3 is controlled by the second heat exchanger 6. During the backflushing desorption, the second adsorption tower 3 first rises to 300°C within 18 minutes and maintains a pressure of 15 bar. Then, the flushing agent enters the second adsorption tower 3 from the bottom and continues to desorb for 162 minutes, resulting in a desorbed liquid with an impurity content of 5%. The desorbed liquid is fed through the desorbed liquid feed pump 10, heat-exchanged in the second heat exchanger 11 (becoming a saturated liquid), and then fed into the distillation column 12. It is heated under medium-pressure steam at 20 bar and distilled at a top pressure of 1 bar and a top temperature of 285°C. The impurity content of the bottom distillate is 86 ppm. The obtained bottom distillate and the remaining liquid phase stream are output as products. The first adsorption column 2 is then regenerated. In the first regeneration process, the temperature is maintained at 300°C, and the pressure of the first adsorption column 2 is reduced to 0.2 bar for 150 minutes. Then, a second regeneration process is performed, where the column pressure is increased to 15 bar, and the temperature is reduced to 100°C within 30 minutes, restoring the first adsorption column 2 to its initial state.

[0093] After the third adsorption is completed, N-propylcarbazole hydrogen storage material containing 0.8% of the pyrolysis product impurities (e.g., carbazole, dodecahydrocarbazole, octahydrocarbazole, tetrahydrocarbazole) from the liquid phase feedstock is introduced into the first adsorption tower 2 from the top for the third adsorption under conditions of 100°C and 15 bar via feedstock pump 1. The adsorption temperature in the first adsorption tower 2 is controlled by the first heat exchanger 5. The impurities are adsorbed by the Beta molecular sieve. The operation time is 3 hours, resulting in a liquid stream with the impurity content reduced to 56 ppm. Two-thirds of the liquid stream is output as product. One-third of the liquid phase stream is used as a flushing agent, which is heated by the first heat exchanger 8 at a temperature of 300°C. The flushing agent feed pump 9 enters the third adsorption tower 4 from the bottom of the tower for backflushing desorption. The adsorption temperature in the third adsorption tower 4 is controlled by the third heat exchanger 7. During the backflushing desorption, the third adsorption tower 4 first rises to 300°C within 18 minutes and maintains a pressure of 15 bar. Then, the flushing agent enters the third adsorption tower 4 from the bottom and continues to desorb for 162 minutes, resulting in a desorbed liquid with an impurity content of 5%. The desorbed liquid is fed through the desorbed liquid feed pump 10, heat-exchanged in the second heat exchanger 11 (becoming a saturated liquid), and then fed into the distillation column 12. It is heated under medium-pressure 20 bar steam and distilled at a top pressure of 1 bar and a top temperature of 285°C. The impurity content of the bottom distillate is 86 ppm. The obtained bottom distillate and the remaining liquid phase stream are output as products. The second adsorption column 3 is then regenerated. In the first regeneration process, the temperature is maintained at 300°C, and the pressure of the second adsorption column 3 is reduced to 0.2 bar for 150 minutes. Then, in the second regeneration process, the pressure is increased to 15 bar, and the temperature is reduced to 100°C within 30 minutes, restoring the second adsorption column 3 to its initial state.

[0094] The following examples illustrate only a set of processes (adsorption-backwash desorption-regeneration) that are performed simultaneously during continuous operation.

[0095] Example 2 The method is the same as in Example 1, except that vacuum distillation is performed with a top pressure of 0.3 bar; the impurity content in the liquid stream is reduced to 88 ppm, the impurity content in the desorbate is 3.3%, and the impurity content in the bottom distillate is 156 ppm.

[0096] Example 3 In this embodiment, Ar is used to control the pressure during the impurity separation process in the liquid phase, and the adsorption tower has a built-in coil for heat extraction, with ethylene glycol as the heat extraction medium. Specifically, as follows... Figure 1 As shown, Adsorption: An N-methylcarbazole hydrogen storage compound containing 0.5% of N-methylcarbazole hydrogen slurry (containing impurities such as carbazole, dodecahydrocarbazole, octahydrocarbazole, and tetrahydrocarbazole) from the pyrolysis products of the liquid-phase feedstock is introduced into the first adsorption tower 2 from the top via the feedstock pump 1 for initial adsorption. The adsorption temperature in the first adsorption tower 2 is controlled by the first heat exchanger 5. The impurities are absorbed by mordenite zeolite (specific surface area: 641 m²). 2 / g, adsorbent shape: columnar) adsorbed, operation time is 4 hours, liquid phase stream is obtained, the impurity content in the liquid phase stream is reduced to 63 ppm, 3 / 4 of the liquid phase stream is output as product.

[0097] Backflushing Desorption: One-quarter of the liquid phase stream is used as a flushing agent, which is heated by the first heat exchanger 8 at 300°C. The flushing agent feed pump 9 then feeds the stream into the second adsorption tower for backflushing desorption. The adsorption temperature in the second adsorption tower 3 is controlled by the second heat exchanger 6. During backflushing desorption, the second adsorption tower 3 first reaches 300°C within 15 minutes and maintains a pressure of 10 bar. Then, the flushing agent enters from the bottom of the second adsorption tower 3 and continues desorption for 225 minutes, yielding a desorbed liquid with an impurity content of 3.1%. The desorbed liquid is fed by the desorbed liquid feed pump 10, heated by the second heat exchanger 11 (becoming a saturated liquid), and then fed into the distillation column 12. It is heated under medium-pressure 20 bar steam and distilled at a top pressure of 1 bar and a top temperature of 256°C. The impurity content of the bottom distillate is 73 ppm, which can be directly output as the product.

[0098] Regeneration: In the first regeneration process, the temperature is maintained at 300°C, the pressure of the third adsorption tower 4 is reduced to 0.2 bar and maintained for 210 minutes. Then, the second regeneration process is carried out, the tower pressure is increased to 10 bar, and the temperature is reduced to 125°C within 30 minutes, and the adsorption tower is restored to its initial state.

[0099] Example 4 In this embodiment, N2 is used to control the pressure during the impurity separation process in the liquid phase, and the adsorption tower uses a built-in coil for heat extraction, with water as the heat extraction medium. Specifically, as follows... Figure 1 As shown, Adsorption: An N-butylcarbazole hydrogen storage compound containing 0.6% of N-butylcarbazole hydrogen slurry (containing impurities such as carbazole, dodecahydrocarbazole, octahydrocarbazole, and tetrahydrocarbazole) from the pyrolysis products of the liquid-phase feedstock is introduced into the first adsorption tower 2 from the top via a feed pump 1 for initial adsorption. The adsorption temperature in the first adsorption tower 2 is controlled by a first heat exchanger 5. The impurities are absorbed by the Y molecular sieve (specific surface area: 643 m²). 2 / g, adsorbent shape: spherical) adsorbed, operation time is 5 hours, liquid phase stream is obtained, the impurity content in the liquid phase stream is reduced to 31 ppm, 4 / 5 of the liquid phase stream is output as product.

[0100] Backflushing Desorption: One-fifth of the liquid phase stream is used as a flushing agent, which is heated by the first heat exchanger 8 at 200°C. The flushing agent feed pump 9 then feeds the stream into the second adsorption tower for backflushing desorption. The adsorption temperature in the second adsorption tower 3 is controlled by the second heat exchanger 6. During backflushing desorption, the second adsorption tower 3 first reaches 200°C within 30 minutes and maintains a pressure of 5 bar. Then, the flushing agent enters from the bottom of the second adsorption tower 3 and continues desorption for 270 minutes, yielding a desorbed liquid with an impurity content of 2.8%. The desorbed liquid is fed by the desorbed liquid feed pump 10, heated by the second heat exchanger 11 (becoming a saturated liquid), and then fed into the distillation column 12. It is heated under medium-pressure steam at 15 bar and distilled at a top pressure of 1 bar and a top temperature of 243°C. The impurity content of the bottom distillate is 60 ppm, which can be directly output as the product.

[0101] Regeneration: In the first regeneration process, the temperature is maintained at 200°C, the pressure of the third adsorption tower 4 is reduced to 0.2 bar and maintained for 240 minutes. Then, the second regeneration process is carried out, the tower pressure is increased to 5 bar, and the temperature is reduced to 100°C within 60 minutes, and the adsorption tower is restored to its initial state.

[0102] Example 5 The method is the same as in Example 3, except that the adsorbent is activated carbon (specific surface area: 861 m²). 2 / g, adsorbent shape: columnar). The impurity content in the liquid stream was reduced to 93 ppm, the impurity content in the desorption liquid was 2.4%, and the impurity content in the bottom distillate was 345 ppm.

[0103] Example 6 In this embodiment, N2 is used to control the pressure during the impurity separation process in the liquid phase, and the adsorption tower has a built-in coil for heat extraction, with ethylene glycol as the heat extraction medium. Specifically, as follows... Figure 1 As shown, Adsorption: Impurities from the pyrolysis products of the liquid-phase feedstock (e.g., dihydroindole, tetrahydroindole, octahydroindole) containing 0.8% N-methylindole are introduced into the first adsorption tower 2 via feed pump 1 from the top for initial adsorption. The adsorption temperature in the first adsorption tower 2 is controlled by the first heat exchanger 5. The impurities are absorbed by Beta molecular sieves (specific surface area: 571.3 m²). 2 / g, adsorbent shape: strip) adsorbed, operation time is 3 hours, liquid phase stream is obtained, the impurity content in the liquid phase stream is reduced to 69 ppm, 2 / 3 of the liquid phase stream is output as product.

[0104] Backflushing Desorption: One-third of the liquid phase stream is used as a flushing agent, which is heated by the first heat exchanger 8 to a temperature of 280°C. The flushing agent feed pump 9 then feeds the stream into the second adsorption tower for backflushing desorption. The adsorption temperature in the second adsorption tower 3 is controlled by the second heat exchanger 6. During backflushing desorption, the second adsorption tower 3 first reaches 280°C within 18 minutes and maintains a pressure of 12 bar. Then, the flushing agent enters from the bottom of the second adsorption tower 3 and continues desorption for 162 minutes, yielding a desorbed liquid with an impurity content of 4.5%. The desorbed liquid is fed by the desorbed liquid feed pump 10, heated by the second heat exchanger 11 (becoming a saturated liquid), and then fed into the distillation column 12. It is heated under medium-pressure steam of 20 bar and distilled at a top pressure of 1 bar and a top temperature of 253°C. The impurity content of the bottom distillate is 91 ppm, which can be directly output as the product.

[0105] Regeneration: In the first regeneration process, the temperature is maintained at 280°C, the pressure of the third adsorption tower 4 is reduced to 0.25 bar and maintained for 140 minutes. Then, the second regeneration process is carried out, the tower pressure is increased to 5 bar, and the temperature is reduced to 120°C within 40 minutes, and the adsorption tower is restored to its initial state.

[0106] Example 7 The method is the same as in Example 6, except that the liquid feedstock is 2,3-dimethylindole with a pyrolysis product impurity (e.g., dihydroindole, tetrahydroindole, octahydroindole) content of 0.8%. The impurity content in the liquid stream is reduced to 97 ppm, the impurity content in the desorption liquid is 2.8%, and the impurity content in the bottom distillate is 531 ppm.

[0107] Example 8 The method is the same as in Example 1, except that the ratio of the running time for the heating stage to the isothermal stage is 1:29. The impurity content in the liquid stream is reduced to 154 ppm, the impurity content in the desorption liquid is 1.6%, and the impurity content in the bottom distillate is 842 ppm.

[0108] Example 9 The method is the same as in Example 3, except that in the first regeneration process, the pressure of the third adsorption tower 4 is reduced to 0.8 bar. The impurity content in the liquid stream is reduced to 167 ppm, the impurity content in the desorbate is 1.8%, and the impurity content in the bottom distillate is 679 ppm.

[0109] Example 10 The method was followed in Example 3, except that the adsorption temperature was 200°C during the adsorption process. The impurity content in the liquid stream was reduced to 198 ppm, the impurity content in the desorption liquid was 1.9%, and the impurity content in the bottom distillate was 943 ppm.

[0110] Example 11 The method is the same as in Example 3, except that 2 / 3 of the liquid stream is used as a rinsing agent. The impurity content in the desorption solution is 1.5%, and the impurity content in the bottom distillate is 761 ppm.

[0111] Comparative Example 1 The method of Example 3 is different in that the liquid stream obtained during adsorption is directly output as a product, and ethanol is used as a washing agent to wash away impurities on the adsorbent. The impurity content in the liquid stream is reduced to 2500 ppm, and the impurity content in the desorption liquid is 0.8%. At this time, the top distillate of the distillation column is ethanol, and the bottom distillate is impurities.

[0112] The introduction of the new component ethanol resulted in a high ethanol content in the adsorption tower, leading to a high ethanol content in the purified liquid stream, which did not meet the requirements for organic liquid hydrogen storage.

[0113] The results above show that, compared with the comparative example, the method used in the embodiment of the present invention has a low content of impurities in the bottom distillate, which solves the problems of low purity, high cost, and easy introduction of new impurities in the existing technology of organic liquid hydrogen storage materials. The embodiment of the method provided by the present invention has the characteristics of high purity, low cost, no introduction of new impurities, high efficiency of separation and significant reduction of energy consumption.

[0114] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for separating impurities in a liquid phase, characterized in that, The method includes: (1) The liquid raw material is contacted with the adsorbent for adsorption to obtain a liquid stream; The liquid-phase feedstock includes organic liquid hydrogen storage materials and impurities; The adsorbent preferentially adsorbs impurities in the liquid phase raw material; (2) A portion of the liquid phase stream is backflushed to desorb the adsorbent, resulting in a desorbed solution; Based on the total mass of the desorption solution, the impurity content in the desorption solution is 2-5%; (3) The desorbed liquid is fed into a distillation column for distillation separation, and the bottom distillate and the remaining liquid phase stream are output as products. (4) Regenerate the adsorbent after backflushing and desorption.

2. The method according to claim 1, wherein, The liquid phase feedstock is selected from hydrogenated N-alkylcarbazole and / or hydrogenated alkyl-substituted indole; Preferably, the N-alkylcarbazole is selected from at least one of N-methylcarbazole, N-propylcarbazole, N-ethylcarbazole, N-butylcarbazole, and N-isopropylcarbazole; Preferably, the alkyl-substituted indole is selected from at least one of N-methylindole, N-ethylindole, 2-methylindole, 7-ethylindole, and 2,3-dimethylindole; And / or, the impurities are pyrolysis products of the liquid-phase feedstock, preferably at least one of carbazole, 4H-carbazole, 8H-carbazole and 12H-carbazole, indole, 2H-indole and 4H-indole; And / or, based on the total mass of the liquid phase feedstock, the impurity content is 0.5-1 wt%; And / or, based on the total mass of the liquid stream, the impurity content in the liquid stream is ≤0.01wt%.

3. The method according to claim 1 or 2, wherein, The amount of adsorbent used is 5-10 v / v% of the liquid phase feed. Preferably, the adsorbent is selected from at least one of γ-alumina, Beta molecular sieve, mordenite, Y molecular sieve, and activated carbon; Preferably, the specific surface area of ​​the adsorbent is greater than 500 m². 2 / g; Preferably, the adsorbent is spherical or columnar; And / or, the adsorption conditions in step (1) include: a temperature of 50-150℃, a pressure of 5-20 bar, and a time of 3-9 h.

4. The method according to any one of claims 1-3, wherein, The flow ratio of the partial liquid phase stream to the remaining liquid phase stream is 1:2-5, preferably 1:2-3; Preferably, the backflushing desorption in step (2) includes a heating stage and a constant temperature stage, and the ratio of the running time of the heating stage to the constant temperature stage is 1:9-30, preferably 1:9-19; And / or, the conditions for backflushing desorption in step (2) include: the temperature during the isothermal stage is 200-350℃, preferably 200-300℃; the pressure is 5-20 bar, preferably 10-20 bar; and the time is 3-9 h, preferably 3-6 h.

5. The method according to any one of claims 1-4, wherein, The distillation described in step (3) is selected from atmospheric distillation and / or vacuum distillation; Preferably, the distillation is heated by medium-pressure steam, with the medium pressure ranging from 15 to 20 bar; Preferably, the conditions for the distillation separation include: a column top pressure of 0.3-1 bar and a column top temperature of 150-300°C; Preferably, based on the total mass of the bottom distillate, the impurity content in the bottom distillate is ≤0.1wt%, more preferably ≤0.06wt%.

6. The method according to any one of claims 1-5, wherein, In step (4), regeneration includes performing a first regeneration process and a second regeneration process in sequence, wherein the temperature of the first regeneration process is higher than that of the second regeneration process, and the pressure of the first regeneration process is lower than that of the second regeneration process. Preferably, the conditions for the first regeneration treatment include: a temperature of 200-350℃, more preferably 200-300℃, a pressure of 0.1-0.5 bar, more preferably 0.2-0.5 bar, and a time of 3-9 hours, more preferably 3-6 hours; Preferably, the conditions for the second regeneration treatment include: a temperature of 50-150°C, more preferably 100-150°C, and a pressure of 5-20 bar, more preferably 5-15 bar; Preferably, the temperature of the first regeneration treatment is 100-250°C higher than that of the second regeneration treatment; Preferably, the pressure of the first regeneration treatment is 4.8-19.5 bar lower than that of the second regeneration treatment; Preferably, the time ratio of the first regeneration treatment to the second regeneration treatment is 3-10:1, more preferably 4-9:

1.

7. The method according to any one of claims 1-6, wherein, The adsorption time in step (1), the backflushing desorption time in step (2), and the regeneration time in step (3) are the same.

8. The method according to any one of claims 1-7, wherein, The method is carried out in a separation system comprising at least three adsorption towers, each filled with an adsorbent that preferentially adsorbs impurities in the liquid phase feedstock. Preferably, in the continuous operation of the method, at least one adsorption tower performs adsorption, at least one adsorption tower performs desorption, and at least one adsorption tower performs regeneration.

9. The method according to claim 8, wherein, The system includes a first adsorption tower, a second adsorption tower, and a third adsorption tower; During continuous operation, the liquid raw material is fed into the first adsorption tower for adsorption. After the first heat exchange is performed using a portion of the liquid stream, the adsorbent in the second adsorption tower is backflushed and desorbed to obtain the desorbed liquid. The desorption solution is fed into a distillation column for distillation separation, and the bottom distillate and the remaining liquid phase are output as products; the third adsorption column is then regenerated. After adsorption is complete, the liquid raw material is sent to the third adsorption tower for adsorption, and a portion of the liquid stream is used to backwash and desorb the adsorbent in the first adsorption tower to obtain the desorbed liquid. After passing through the second heat exchange, the desorbed liquid is sent to a distillation column for distillation separation. The bottom distillate and the remaining liquid phase are output as products. The second adsorption column is then regenerated. Repeat the above process so that the three adsorption towers operate in an alternating cycle.

10. The application of the method according to any one of claims 1-9 in an organic liquid circulating hydrogen storage system.

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