Circulating hydrogen storage and discharge system based on aromatic cycloalkane reaction

Abstract

The invention relates to the technical field of hydrogen storage and release, and discloses a cyclic hydrogen storage and release system based on aromatic cycloalkane reaction, which comprises a hydrogenation reaction unit, a dehydrogenation reaction unit, a gas-liquid separation and compression unit and an adsorption and purification unit which are sequentially connected through pipelines, the hydrogenation reaction unit, the dehydrogenation reaction unit and the gas-liquid separation and compression unit are respectively connected with the heat exchange unit; the hydrogen storage function and the hydrogen desorption function are integrally designed, the microwave heat supply dehydrogenation reactor is designed for the dehydrogenation reaction link with high energy consumption, and compared with the prior art, the microwave heat supply dehydrogenation reactor has the advantages that the heat transfer resistance is reduced, the reaction efficiency is improved, and the energy loss is reduced. The designed gas-liquid separation and adsorption purification technology is coupled, only one compressor is used in the whole process, the purification process is effectively simplified, the operation is simple and convenient, the equipment cost and the hydrogen purification cost are reduced, and the hydrogen yield and the hydrogen storage carrier cyclic utilization rate are improved. The system has the advantages of high hydrogen storage and release efficiency, small system size, high mobility and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen storage and release, and in particular to a cyclic hydrogen storage and release system based on aromatic hydrocarbon cycloalkane reaction. Background Art

[0002] With the recent development of a hydrogen energy industry system and a diverse hydrogen energy application ecosystem, my country's hydrogen production scale has continued to expand and production technology has been continuously improved. As a highly sought-after clean energy carrier, hydrogen boasts a wide range of sources, high energy density, and clean products. However, its flammability and explosiveness, along with its wide range of explosion limits, still present numerous challenges in its storage and transportation.

[0003] Liquid organic hydrogen carrier (LOHC) technology achieves reversible hydrogenation and dehydrogenation reactions under mild conditions, enabling efficient storage and release of hydrogen while also offering the significant advantage of high hydrogen storage density, making it an ideal solution for mobile hydrogen storage applications. Among the numerous liquid hydrogen carrier systems, the "aromatic-cycloalkane" system has shown broad prospects for industrial-scale applications due to its high hydrogen storage density (typically 6-8 wt%), excellent structural stability, mature large-scale preparation processes, and low raw material costs. Because the dehydrogenation step is a highly energy-intensive, endothermic reaction, the key to this technology lies in its optimization and efficient energy utilization.

[0004] Chinese patent document CN113336190A discloses a hydrogenation production method using carbazole components as organic hydrogen storage carriers. This method uses a recycling process to use the direct partial hydrogenation product as an additive to the carbazole raw material, simplifying the hydrogenation process. However, while this method solves the problem of carbazoles' relatively high melting points, the hydrogen storage efficiency of carbazoles in organic liquids is relatively low.

[0005] Chinese patent document CN117366465A discloses an integrated hydrogenation system based on organic liquid hydrogen storage. This system uses ethylcarbazole as the hydrogen storage material and utilizes heat from thermal oil heated by a resistance wire for dehydrogenation. The dehydrogenation step of the liquid organic hydrogen storage material is a highly energy-intensive, endothermic reaction. Therefore, optimizing this dehydrogenation step and ensuring efficient energy utilization are crucial. However, this method does not address the efficiency of heat source utilization.

[0006] Based on the application prospects of hydrogen energy, but the existing technology for hydrogen storage and discharge technology still has defects, a new technical solution is proposed. Summary of the Invention

[0007] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0008] In view of the above problems in the prior art, the present invention is proposed.

[0009] Therefore, the purpose of the present invention is to provide a cyclic hydrogen storage and release system based on aromatic cycloalkane reaction, which aims to solve the problems of complex process flow, low hydrogen storage efficiency and insufficient heat source utilization in the hydrogen storage and release process in the prior art.

[0010] To solve the above technical problems, the present invention provides the following technical solutions: a cyclic hydrogen storage and release system based on aromatic cycloalkane reaction, which includes a hydrogenation reaction unit, a dehydrogenation reaction unit, a gas-liquid separation and compression unit, and an adsorption and purification unit connected in sequence by pipelines, and the hydrogenation reaction unit, dehydrogenation reaction unit, gas-liquid separation and compression unit are also each connected to a heat exchange unit.

[0011] As a preferred embodiment of the cyclic hydrogen storage and release system based on aromatic cycloalkane reaction of the present invention, the heat exchange unit includes an aromatic preheater, an inlet and outlet heat exchanger and a cooler group, and the cooler group includes a first cooler, a second cooler, a third cooler and a fourth cooler.

[0012] As a preferred embodiment of the cyclic hydrogen storage and release system based on aromatic cycloalkane reaction according to the present invention, the cooling temperature range of the first cooler is -10 to 25°C, the cooling temperature range of the second cooler is 20 to 40°C, the cooling temperature range of the third cooler is -10 to 10°C, and the cooling temperature range of the fourth cooler is -10 to 10°C.

[0013] As a preferred embodiment of the cyclic hydrogen storage and release system based on the aromatic-cycloalkane reaction of the present invention, the hydrogenation reaction unit includes an aromatic hydrocarbon storage tank, an aromatic hydrocarbon feed pump, a hydrogenation reactor, a first gas-liquid separation tank and a cycloalkane storage tank; the discharge port of the aromatic hydrocarbon storage tank is connected to the input port of the aromatic hydrocarbon feed pump through a pipeline, the output port of the aromatic hydrocarbon feed pump is connected to the input port of the aromatic hydrocarbon preheater, the output port of the aromatic hydrocarbon preheater is connected to the input port of the hydrogenation reactor through a pipeline, the output port of the hydrogenation reactor is connected to the input port of the first gas-liquid separation tank through a pipeline, the gas phase output port of the first gas-liquid separation tank is connected to the input port of the first cooler, and its liquid phase output port is connected to the input port of the first cooler; the liquid phase output port of the first cooler is connected to the input port of the cycloalkane storage tank through a pipeline.

[0014] As a preferred embodiment of the cyclic hydrogen storage and release system based on aromatic cycloalkane reaction of the present invention, the hydrogen storage carrier aromatic hydrocarbon in the aromatic hydrocarbon storage tank is one or more of toluene, benzene, benzyltoluene, and dibenzyltoluene; the hydrogenation reactor is a fixed bed reactor, the reaction temperature is 100-200°C, and the reaction pressure is 0.5-1.5 MPa; the operating temperature of the first gas-liquid separation tank is -10-25°C, and the operating pressure is 0.5-1.5 MPa.

[0015] As a preferred embodiment of the cyclic hydrogen storage and release system based on the aromatic cycloalkane reaction of the present invention, the dehydrogenation reaction unit includes a cycloalkane feed pump and a dehydrogenation reactor, the discharge port of the cycloalkane storage tank is connected to the input port of the cycloalkane feed pump via a pipeline, the output port of the cycloalkane feed pump is connected to the low-temperature input port of the inlet and outlet heat exchanger via a pipeline, the low-temperature output port of the inlet and outlet heat exchanger is connected to the feed port of the dehydrogenation reactor via a pipeline, the discharge port of the dehydrogenation reactor is connected to the high-temperature input port of the inlet and outlet heat exchanger via a pipeline, and the high-temperature output port of the inlet and outlet heat exchanger is connected to the input port of the second cooler via a pipeline.

[0016] As a preferred embodiment of the cyclic hydrogen storage and release system based on aromatic hydrocarbon cycloalkane reaction of the present invention, the dehydrogenation reactor is a fixed bed reactor using microwave radiation for heating, and the temperature of the reaction zone is 320-370°C.

[0017] As a preferred embodiment of the cyclic hydrogen storage and release system based on aromatic cycloalkane reaction described in the present invention, the gas-liquid separation and compression unit includes a second gas-liquid separation tank, a collection tank, a buffer tank before the booster, a hydrogen compressor and a buffer tank after the booster; the output port of the second cooler is connected to the input port of the second gas-liquid separation tank through a pipeline, the gas phase output port of the second gas-liquid separation tank is connected to the input port of the third cooler through a pipeline, the output port of the third cooler is connected to the input port of the buffer tank before the booster through a pipeline, the gas phase output port of the buffer tank before the booster is connected to the input port of the hydrogen compressor through a pipeline, and the output port of the hydrogen compressor is connected to the hydrogen compressor through a pipeline. The pipeline is connected to the input port of the booster rear buffer tank, the first outlet branch of the booster rear buffer tank is connected to the input port pipeline of the aromatics preheater, the second outlet branch is connected to the input port pipeline of the dehydrogenation reactor, the third outlet branch is connected to the input port pipeline of the fourth cooler, and the fourth outlet branch is a relief gas pipeline; the liquid phase output ports of the second gas-liquid separation tank, the booster front buffer tank, the booster rear buffer tank and the fourth cooler are all connected to the input port of the collecting tank through a pipeline, and the output port of the collecting tank is connected to the feed port of the aromatics storage tank through a pipeline; the liquid phase output port of the first cooler is connected to the input port of the booster front buffer tank through a pipeline.

[0018] As a preferred embodiment of the cyclic hydrogen storage and release system based on aromatic cycloalkane reaction of the present invention, the adsorption and purification unit includes an adsorption tower and a desorption gas buffer tank, the gas phase output port of the fourth cooler is connected to the purified gas inlet of the adsorption tower through a pipeline, and the purified gas outlet of the adsorption tower is connected to the input port of the desorption gas buffer tank through a pipeline;

[0019] The output port of the desorbed gas buffer tank is connected to the input port pipeline of the aromatics preheater through a pipeline.

[0020] As a preferred embodiment of the cyclic hydrogen storage and release system based on aromatic cycloalkane reaction described in the present invention, the adsorbent filled in the adsorption tower is activated carbon, alumina or molecular sieve, and it is a two-tower temperature swing adsorption, including two towers A / B that alternately adsorb and desorb, and the desorption operating temperature range is 150-350°C.

[0021] Beneficial effects of the present invention:

[0022] The present invention provides a cyclic hydrogen storage and release system based on the reaction of aromatic hydrocarbons and cycloalkanes, which integrates the hydrogen storage function with the hydrogen release function, and designs a microwave heating dehydrogenation reactor for the high-energy consumption dehydrogenation reaction link. Compared with the existing technology, it reduces the heat transfer resistance, improves the reaction efficiency, and reduces energy loss; the designed gas-liquid separation and adsorption purification technology are coupled, and only one compressor is used in the whole process, which effectively simplifies the purification process, is easy to operate, reduces the equipment cost and hydrogen purification cost, and improves the hydrogen yield and the recycling rate of the hydrogen storage carrier; it has the advantages of high hydrogen storage and release efficiency, small system size, strong mobility, etc., and provides an efficient solution for the on-board application of hydrogen energy and other distributed hydrogen energy application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0024] Figure 1 The figure is a schematic diagram of the modular process of the cyclic hydrogen storage and release system based on the aromatic hydrocarbon cycloalkane reaction of the present invention.

[0025] Figure 2 This is a specific diagram of the structure of the cyclic hydrogen storage and release system based on the aromatic hydrocarbon cycloalkane reaction of the present invention.

[0026] Figure 3 This is a process flow chart of the cyclic hydrogen storage and release system based on the aromatic hydrocarbon cycloalkane reaction of the present invention.

[0027] Figure 4This is the static isothermal adsorption curve of the activated carbon adsorbent used in the examples of the present invention.

[0028] Figure 5 This is the dynamic breakthrough curve of the activated carbon adsorbent used in the examples of the present invention. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0031] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0032] Furthermore, the present invention is described in detail with reference to schematic diagrams. For ease of illustration, when describing the embodiments of the present invention, cross-sectional views illustrating device structures may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely illustrative and should not limit the scope of protection of the present invention. Furthermore, in actual production, the three-dimensional dimensions of length, width, and depth should be included.

[0033] Reference Figures 1 to 3, which is the first embodiment of the present invention, provides a cyclic hydrogen storage and release system based on aromatic cycloalkane reaction, which is used for aromatic hydrogenation reaction to achieve hydrogen storage and cycloalkane dehydrogenation reaction and purification to achieve hydrogen release. This hydrogen storage and release system includes a hydrogenation reaction unit 10, a dehydrogenation reaction unit 20, a gas-liquid separation and compression unit 30, an adsorption and purification unit 40 and a heat exchange unit 50, wherein the hydrogenation reaction unit 10, the dehydrogenation reaction unit 20, the gas-liquid separation and compression unit 30 and the adsorption and purification unit 40 are connected in sequence through pipelines to achieve hydrogen storage and release; and the heat exchange unit 50 is connected to the hydrogenation reaction unit 10, the dehydrogenation reaction unit 20, the gas-liquid separation and compression unit 30 and the adsorption and purification unit 40 in sequence through pipelines to achieve hydrogen storage and release; The various pipelines of the hydrogen reaction unit 20 and the gas-liquid separation and compression unit 30 are thermally connected to adjust the temperature of the materials in the pipes; further, the hydrogenation reaction unit 10 realizes the storage of hydrogen through the catalytic hydrogenation reaction of aromatics; the dehydrogenation reaction unit 20 realizes the release of hydrogen through the catalytic dehydrogenation reaction of cycloalkanes heated by microwaves; the gas-liquid separation and compression unit 30 is used to perform gas-liquid separation on the dehydrogenation reaction output and to pressurize the circulating hydrogen, and its gas phase outlet is connected to the feed port of the adsorption purification unit 40; the adsorption and purification unit 40 is used to purify the gas phase material obtained by the gas-liquid separation and compression system to obtain a high-purity hydrogen product.

[0034] During actual operation, the hydrogen storage carrier aromatic hydrocarbons and hydrogen are preheated by the heat exchange unit 50, enter the hydrogenation reaction unit 10, and form hydrogen-rich cycloalkanes through the liquid phase discharge of the hydrogen reaction unit 10, and enter the dehydrogenation reaction unit 20 through the cycloalkane storage tank 15. After the reaction, the gas phase discharge of the dehydrogenation reaction unit 20 enters the feed port of the hydrogen compressor 34 in the gas-liquid separation and compression unit 30, and its liquid phase discharge enters the feed port of the cycloalkane storage tank 15.

[0035] Furthermore, the discharge of the cycloalkane storage tank 15 enters the feed end of the dehydrogenation reaction unit 20 after passing through the heat exchange system unit 50, and the discharge of the dehydrogenation reaction unit 20 enters the inlet end of the gas-liquid separation and compression unit 30. The discharge end of the gas-liquid separation and compression unit 20 includes liquid phase discharge, hydrogenation cycle hydrogen discharge, dehydrogenation cycle hydrogen discharge, gas phase discharge and purge gas discharge, wherein the purge gas discharge is controlled by the system pressure, and the liquid phase discharge of the gas-liquid separation and compression unit 30 returns to the aromatics storage tank 11, and the gas-liquid separation and compression unit 30 is discharged. The hydrogen output from the hydrogenation cycle enters the feed end of the hydrogenation reaction unit 10 and circulates as a hydrogenation carrier gas. The hydrogen output from the dehydrogenation cycle of the gas-liquid separation and compression unit 30 enters the feed end of the dehydrogenation reaction unit 20 and circulates as a dehydrogenation carrier gas. The gas phase output from the gas-liquid separation and compression unit 30 enters the feed end of the adsorption purification unit 40, and the discharge end of the adsorption purification unit 40 is a hydrogen product. The hydrogenation reaction unit 10, the dehydrogenation reaction unit 20 and the gas-liquid separation and compression unit 30 are all integrated through the heat exchange unit 50 to control the heating or cooling of the fluid.

[0036] Specifically, the heat exchange unit 50 includes an aromatic preheater 51, an inlet and outlet heat exchanger 52 and a cooler group 53, and the cooler group 53 includes a first cooler 53a, a second cooler 53b, a third cooler 53c and a fourth cooler 53d; it should be noted that each heat exchanger in the heat exchange unit 50 is arranged based on a heat exchange network designed based on logistics properties.

[0037] Among them, the aromatics preheater 51 is used to preheat the input material of the hydrogenation reactor 13, and the inlet and outlet heat exchanger 52 is used to preheat the feed of the dehydrogenation reactor 22. The high-temperature material of this reactor is the high-temperature airflow at the outlet of the dehydrogenation reactor 22, thereby realizing efficient energy utilization; the first cooler 53a in the cooler group 53 is used to cool the outlet material of the hydrogenation reactor 13; the second cooler 53b and the third cooler 53c are used to cool the outlet gas of the dehydrogenation reaction of the gas-liquid separation and compression unit 30; and the fourth cooler 53d is used to cool the crude gas phase diverted from the compressor outlet to the adsorption purification separation.

[0038] Furthermore, the cooling temperature range of the first cooler 53a is -10 to 25°C, preferably 20°C; the cooling temperature range of the second cooler 53b is 20 to 40°C, preferably 30°C; the cooling temperature range of the third cooler 53c is -10 to 10°C, preferably 0°C; and the cooling temperature range of the fourth cooler 53d is -10 to 10°C, further preferably 0°C.

[0039] The hydrogenation reaction unit 10 includes an aromatics storage tank 11, an aromatics feed pump 12, a hydrogenation reactor 13, a first gas-liquid separation tank 14 and a cycloalkane storage tank 15; the discharge port of the aromatics storage tank 11 is connected to the input port of the aromatics feed pump 12 through a pipeline, the output port of the aromatics feed pump 12 is connected to the input port of the aromatics preheater 51, the output port of the aromatics preheater 51 is connected to the input port of the hydrogenation reactor 13 through a pipeline, the output port of the hydrogenation reactor 13 is connected to the input port of the first gas-liquid separation tank 14 through a pipeline, the gas phase output port of the first gas-liquid separation tank 14 is connected to the input port of the first cooler 53a, and its liquid phase output port is connected to the input port of the cycloalkane storage tank 15; the liquid phase output port of the first cooler 53a is connected to the input port of the cycloalkane storage tank 15 through a pipeline.

[0040] Furthermore, the hydrogen storage carrier aromatic hydrocarbon in the aromatic hydrocarbon storage tank 11 is one or more of toluene, benzene, benzyltoluene, and dibenzyltoluene; the hydrogenation reactor 13 is a fixed-bed reactor, with a reaction temperature of 100-200°C, preferably 150°C; and a reaction pressure of 0.5-1.5 MPa, preferably 0.8 MPa; and a ruthenium-on-carbon catalyst can be used as the catalyst in the hydrogenation reactor 13. Furthermore, the operating temperature of the first cooler 53a and the first gas-liquid separator 14 is -10-25°C, preferably 20°C, and the operating pressure is 0.5-1.5 MPa, preferably 0.8 MPa.

[0041] The dehydrogenation reaction unit 20 includes a cycloalkane feed pump 21 and a dehydrogenation reactor 22. Specifically, the discharge port of the cycloalkane storage tank 15 is connected to the input port of the cycloalkane feed pump 21 via a pipeline, the output port of the cycloalkane feed pump 21 is connected to the low-temperature input port of the inlet and outlet heat exchanger 52 via a pipeline, the low-temperature output port of the inlet and outlet heat exchanger 52 is connected to the feed port of the dehydrogenation reactor 22 via a pipeline, the discharge port of the dehydrogenation reactor 22 is connected to the high-temperature input port of the inlet and outlet heat exchanger 52 via a pipeline, and the high-temperature output port of the inlet and outlet heat exchanger 52 is connected to the input port of the second cooler 53b via a pipeline.

[0042] The dehydrogenation reactor 22 is a fixed-bed reactor using microwave radiation for heating, with a reaction zone temperature of 320-370°C. Preferably, the fixed-bed reactor using microwave radiation for heating is a five-source single-tube microwave reactor with waveguides evenly spaced along the circumference, which selectively heats the bed with microwaves. Preferably, the reactor temperature is monitored by an infrared camera, and changes in microwave power are linked to temperature changes to accommodate hydrogen production under varying operating conditions.

[0043] Furthermore, the catalyst bed (reaction zone) temperature of the dehydrogenation reactor 22 is 320-370°C, more preferably 350°C. Preferably, the catalyst bed comprises a monolithic catalyst containing a platinum-based catalyst and an absorbent material, more preferably a monolithic catalyst containing a platinum-based catalyst and SiC. The mass ratio of SiC to platinum-based catalyst is 1-5, more preferably 3.

[0044] The catalyst is prepared as follows: 1.3 mol / L sodium aluminate solution is added dropwise to 150 mL of 20% sulfuric acid solution under stirring into deionized water, followed by the addition of 400 mL of 1.3 mol / L sodium aluminate solution under stirring to obtain a white flocculent slurry with a pH of 10. This alternating addition of acid and base solutions is repeated three times. Filtering, washing, drying, and calcining at 500°C for 3 hours produce the carrier Al2O3. Using the impregnation method, an appropriate amount of chloroplatinic acid (Aladdin) is weighed to prepare a chloroplatinic acid solution, which is mixed with the carrier Al2O3. Water is removed by a rotary evaporator and calcined at 400°C for 3 hours, which is recorded as Pt / Al2O3. Using the impregnation method, an appropriate amount of potassium nitrate (Aladdin) is weighed to prepare a potassium nitrate solution, which is mixed with the obtained Pt / Al2O3. Water is removed by a rotary evaporator to obtain the catalyst PtK / Al2O3, which is the platinum-based catalyst.

[0045] Furthermore, the inlet flow of the (microwave-heated) dehydrogenation reactor 22 is a mixture of preheated cycloalkanes, hydrocarbons, and recycled hydrogen, and this mixture has a certain molar flow rate ratio of hydrogen to cycloalkanes, which is 0 to 3, and more preferably 0.57. And preferably, the mass space velocity of methylcyclohexane in the hydrogenation reactor 13 is 6 to 35h -1 , more preferably 10 to 14 hours -1 , specifically preferably 12h -1 .

[0046] The gas-liquid separation and compression unit 30 includes a second gas-liquid separation tank 31, a collection tank 32, a supercharger front buffer tank 33, a hydrogen compressor 34 and a supercharger rear buffer tank 35; specifically, the output port of the second cooler 53b is connected to the input port of the second gas-liquid separation tank 31 through a pipeline, the gas phase output port of the second gas-liquid separation tank 31 is connected to the input port of the third cooler 53c through a pipeline, the output port of the third cooler 53c is connected to the input port of the supercharger front buffer tank 33 through a pipeline, the gas phase output port of the supercharger front buffer tank 33 is connected to the hydrogen compressor 34 through a pipeline. The output port of the hydrogen compressor 34 is connected to the input port of the booster buffer tank 35 through a pipeline. The first outlet branch D1 of the booster buffer tank 35 is connected to the input port pipeline of the aromatics preheater 51 or is electrically connected to the feed of the hydrogenation reactor 13 for hydrogenation reaction circulation; the second outlet branch D2 is connected to the input port pipeline of the dehydrogenation reactor 22 for dehydrogenation reaction circulation hydrogen; the third outlet branch D3 is connected to the input port pipeline of the fourth cooler 53d; the fourth outlet branch D4 is a purge gas pipeline for controlling the system pressure.

[0047] Furthermore, the liquid phase output ports of the second gas-liquid separation tank 31, the booster pre-buffer tank 33, the booster post-buffer tank 35 and the fourth cooler 53d are all connected to the input port of the collecting tank 32 through pipelines, and the output port of the collecting tank 32 is connected to the feed port of the aromatics storage tank 11 through a pipeline; the liquid phase output port of the first cooler 53a is connected to the input port of the booster pre-buffer tank 33 through a pipeline.

[0048] The adsorption and purification unit 40 includes an adsorption tower 41 and a desorption gas buffer tank 42, wherein the gas phase output port of the fourth cooler 53d is connected to the purified gas inlet of the adsorption tower 41 in the adsorption working state through a pipeline, and the purified gas outlet of the adsorption tower 41 is connected to the input port of the desorption gas buffer tank 42, and its purified gas outlet outputs purified hydrogen.

[0049] It should be noted that the adsorbent filled in the adsorption tower 41 is activated carbon, alumina or molecular sieve. It is a two-tower temperature-swing adsorption, including two towers A / B that work alternately for adsorption and desorption, and the desorption working temperature range is 150-350°C, and more preferably 300°C.

[0050] Furthermore, the output port (output hydrogen) of the desorption gas buffer tank 42 is directly connected to the inlet end of the hydrogenation reaction unit 10 to serve as raw hydrogen for the hydrogenation reaction.

[0051] Example

[0052] Reference Figures 1 to 5 This is an embodiment of the present invention, utilizing the aforementioned cyclic hydrogen storage and release system based on the aromatic cycloalkane reaction to store and release hydrogen. This system includes a hydrogenation reaction unit 10, a dehydrogenation reaction unit 20, a gas-liquid separation and compression unit 30, an adsorption and purification unit 40, and a heat exchange unit 50. The liquid organic hydrogen storage carrier used in this embodiment is a toluene-methylcyclohexane system.

[0053] It should be noted that the (microwave-heated) dehydrogenation reactor 22 has a heating device with five microwave sources orthogonally distributed. The reactor is filled with a monolithic catalyst mixed with SiC and platinum-based catalysts (mixing mass ratio of 3), and the catalyst bed is selectively heated by microwave radiation.

[0054] Furthermore, the adsorbent filled in the adsorption tower 41 is commercial activated carbon.

[0055] Further, Figure 3 The adsorption isotherm of the activated carbon is given in ; Figure 4 The dynamic penetration curve of the activated carbon under a 2000ppm CH4 / H2 toluene saturated gas flow at -9°C is given, and the relationship between the adsorption capacity of the activated carbon and the filling amount of 41 activated carbon in the adsorption tower is determined.

[0056] In this embodiment, the working principle of hydrogen storage is as follows: the raw material toluene is transported from the aromatic hydrocarbon storage tank 11 by the aromatic hydrocarbon feed pump 12, and is mixed with hydrogen, circulating hydrogen, and desorbed gas and then enters the hydrogenation reactor 13 through the aromatic hydrocarbon preheater 51. The product gas at the outlet of the hydrogenation reactor 13 enters the first gas-liquid separation tank 15 for gas-liquid separation after air cooling. The liquid phase is the product methylcyclohexane entering the cycloalkane storage tank 15. The gas is further separated from the gas and liquid after being cooled at 20°C by the first cooler 53a. The gas phase enters the buffer tank 33 before the supercharger, is compressed to 1MPa by the hydrogen compressor 34, and returns to the input port of the aromatic hydrocarbon preheater 51 through the first branch D1 of the outlet of the buffer tank 35 after the supercharger as hydrogen circulation hydrogen. The system pressure is controlled by the purge gas of the fourth branch D4. The hydrogenation reaction temperature is 150°C, the reaction pressure is 0.8MPa, the molar flow rate ratio of hydrogen to methylcyclohexane is 7.5, and the mass air velocity of toluene is 5h -1 , achieving a toluene hydrogenation conversion rate greater than 99% and a hydrogen storage rate greater than 5gH2 / min.

[0057] In this embodiment, the working principle of hydrogen release is as follows: the raw material methylcyclohexane is transported from the cyclohexane storage tank to the inlet and outlet heat exchanger 52 by the cycloalkane feed pump 21, mixed with the dehydrogenation circulating hydrogen after preheating, and enters the (microwave heated) dehydrogenation reactor 22. The gas produced at the outlet of the (microwave heated) dehydrogenation reactor 22 enters the inlet and outlet heat exchanger 52, and then enters the gas-liquid separation and compression unit 30 for gas-liquid separation.

[0058] The initially cooled product gas is cooled at 30°C by the second cooler 53b and then enters the second gas-liquid separation tank 31. The gas at the top of the second gas-liquid separation tank 31 is deeply cooled at 0°C by the third cooler 53c and then enters the booster pre-buffer tank 33. The gas at the top of the booster pre-buffer tank 33 enters the hydrogen compressor 34 and is pressurized to 1MPa. The second branch D2 of the booster post-buffer tank 35 returns to the front end of the (microwave heating) dehydrogenation reactor 22 as dehydrogenation circulating hydrogen; the system pressure is controlled by the fourth branch D4 purge gas; the third branch D3 of the booster post-buffer tank 35 outputs crude hydrogen, which enters the adsorption and separation process after being cooled at 0°C by the fourth cooler 53d.

[0059] Furthermore, the liquid toluene at the bottom of the second gas-liquid separation tank 31, the booster pre-buffer tank 33, the booster post-buffer tank 35, and the fourth cooler 53d is returned to the aromatics storage tank 11 through the collection tank 32. (Microwave heating) The average temperature of the dehydrogenation reactor 22 is 150°C, the molar flow rate ratio of hydrogen to methylcyclohexane is 0.56, and the mass space velocity of methylcyclohexane is 11.5h -1 , achieving a methylcyclohexane dehydrogenation conversion rate greater than 99%, a by-product methane content less than 10 ppm, and a hydrogen release rate greater than 5 gH2 / min.

[0060] The two towers in the adsorption tower 41 are alternately in adsorption or desorption mode. Crude hydrogen enters the adsorption tower in the adsorption mode of the adsorption tower 41 to obtain a purified hydrogen product. Fresh hydrogen enters the adsorption tower in the desorption mode of the adsorption tower 41 as a desorption carrier gas. The adsorption tower in the desorption mode is heated to 300°C to regenerate the adsorbent. The outlet desorbed gas passes through the desorbed gas buffer tank 42, and the top gas phase can be used as the hydrogen feedstock for the hydrogenation reaction. Through the gas-liquid separation and compression system and the adsorption purification system, the hydrogen quality purity can be achieved to be greater than 99.99%, the hydrogen yield is greater than 99%, and the carrier hydrogen storage density reaches 6.15%.

[0061] In this embodiment, the hydrogen storage function and the hydrogen release function can be operated independently or simultaneously.

[0062] The present invention provides a cyclic hydrogen storage and release system based on the reaction of aromatic hydrocarbons and cycloalkanes, wherein the hydrogen storage function and the hydrogen release function can be operated separately or simultaneously; the hydrogen storage function and the hydrogen release function are integrated into an integrated design to achieve efficient recycling of the carrier, which is conducive to the miniaturization and skid-mounting of the integrated hydrogen storage and release system; a microwave heating dehydrogenation reactor is designed for the key dehydrogenation reaction link with high energy consumption, overcoming the traditional problems of large temperature gradient and high energy dissipation, and achieving efficient and high selectivity of the dehydrogenation reaction; by coupling gas-liquid separation with adsorption purification technology, only one compressor is required in the entire process, which achieves high hydrogen output while further simplifying the purification system and its operation, reducing equipment cost and hydrogen purification cost, and improving hydrogen yield and recycling rate of hydrogen storage carrier.

[0063] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A cyclic hydrogen storage and release system based on aromatic hydrocarbon cycloalkane reaction, characterized by: The invention comprises a hydrogenation reaction unit (10), a dehydrogenation reaction unit (20), a gas-liquid separation and compression unit (30), and an adsorption and purification unit (40) which are sequentially connected through pipelines, and the hydrogenation reaction unit (10), the dehydrogenation reaction unit (20), and the gas-liquid separation and compression unit (30) are also each connected to a heat exchange unit (50) through a pipeline.

2. The cyclic hydrogen storage and release system based on aromatic hydrocarbon cycloalkane reaction according to claim 1 is characterized in that: The heat exchange unit (50) includes an aromatic hydrocarbon preheater (51), an inlet and outlet heat exchanger (52) and a cooler group (53), and the cooler group (53) includes a first cooler (53a), a second cooler (53b), a third cooler (53c) and a fourth cooler (53d).

3. The cyclic hydrogen storage and release system based on aromatic hydrocarbon cycloalkane reaction according to claim 2 is characterized in that: The cooling temperature range of the first cooler (53a) is -10 to 25°C, the cooling temperature range of the second cooler (53b) is 20 to 40°C, the cooling temperature range of the third cooler (53c) is -10 to 10°C, and the cooling temperature range of the fourth cooler (53d) is -10 to 10°C.

4. The cyclic hydrogen storage and release system based on aromatic cycloalkane reaction according to claim 2 or 3, characterized in that: The hydrogenation reaction unit (10) includes an aromatic hydrocarbon storage tank (11), an aromatic hydrocarbon feed pump (12), a hydrogenation reactor (13), a first gas-liquid separation tank (14) and a cycloalkane storage tank (15); The discharge port of the aromatic hydrocarbon storage tank (11) is connected to the input port of the aromatic hydrocarbon feed pump (12) through a pipeline, the output port of the aromatic hydrocarbon feed pump (12) is connected to the input port of the aromatic hydrocarbon preheater (51), the output port of the aromatic hydrocarbon preheater (51) is connected to the input port of the hydrogenation reactor (13) through a pipeline, the output port of the hydrogenation reactor (13) is connected to the input port of the first gas-liquid separation tank (14) through a pipeline, the gas phase output port of the first gas-liquid separation tank (14) is connected to the input port of the first cooler (53a), and the liquid phase output port thereof is connected to the input port of the cycloalkane storage tank (15); The liquid phase output port of the first cooler (53a) is connected to the input port of the cycloalkane storage tank (15) through a pipeline.

5. The cyclic hydrogen storage and release system based on aromatic hydrocarbon cycloalkane reaction according to claim 4 is characterized in that: The hydrogen storage carrier aromatic hydrocarbon in the aromatic hydrocarbon storage tank (11) is one or more of toluene, benzene, benzyltoluene, and dibenzyltoluene; The hydrogenation reactor (13) is a fixed bed reactor with a reaction temperature of 100-200°C and a reaction pressure of 0.5-1.5 MPa; The operating temperature of the first gas-liquid separation tank (14) is -10 to 25°C, and the operating pressure is 0.5 to 1.5 MPa.

6. The cyclic hydrogen storage and release system based on aromatic hydrocarbon cycloalkane reaction according to claim 5, characterized in that: The dehydrogenation reaction unit (20) comprises a cycloalkane feed pump (21) and a dehydrogenation reactor (22); the discharge port of the cycloalkane storage tank (15) is connected to the input port of the cycloalkane feed pump (21) via a pipeline; the output port of the cycloalkane feed pump (21) is connected to the low-temperature input port of the inlet and outlet heat exchanger (52) via a pipeline; the low-temperature output port of the inlet and outlet heat exchanger (52) is connected to the feed port of the dehydrogenation reactor (22) via a pipeline; the discharge port of the dehydrogenation reactor (22) is connected to the high-temperature input port of the inlet and outlet heat exchanger (52) via a pipeline; and the high-temperature output port of the inlet and outlet heat exchanger (52) is connected to the input port of the second cooler (53b) via a pipeline.

7. The cyclic hydrogen storage and release system based on aromatic hydrocarbon cycloalkane reaction according to claim 6, characterized in that: The dehydrogenation reactor (22) is a fixed bed reactor that uses microwave radiation to provide heat, and the temperature of its reaction zone is 320-370°C.

8. The cyclic hydrogen storage and release system based on aromatic cycloalkane reaction according to claim 6 or 7, characterized in that: The gas-liquid separation and compression unit (30) includes a second gas-liquid separation tank (31), a collection tank (32), a booster front buffer tank (33), a hydrogen compressor (34) and a booster rear buffer tank (35); The output port of the second cooler (53b) is connected to the input port of the second gas-liquid separation tank (31) through a pipeline, the gas phase output port of the second gas-liquid separation tank (31) is connected to the input port of the third cooler (53c) through a pipeline, the output port of the third cooler (53c) is connected to the input port of the booster front buffer tank (33) through a pipeline, and the gas phase output port of the booster front buffer tank (33) is connected to the input port of the hydrogen compressor (34) through a pipeline. The output port of the hydrogen compressor (34) is connected to the input port of the booster rear buffer tank (35) through a pipeline. The first outlet branch (D1) of the booster rear buffer tank (35) is connected to the input port pipeline of the aromatic hydrocarbon preheater (51), the second outlet branch (D2) is connected to the input port pipeline of the dehydrogenation reactor (22), the third outlet branch (D3) is connected to the input port pipeline of the fourth cooler (53d), and the fourth outlet branch (D4) is a purge gas pipeline. The liquid phase output ports of the second gas-liquid separation tank (31), the booster front buffer tank (33), the booster rear buffer tank (35) and the fourth cooler (53d) are all connected to the input port of the collection tank (32) through pipelines, and the output port of the collection tank (32) is connected to the feed port of the aromatic hydrocarbon storage tank (11) through a pipeline; The gas phase output port of the first cooler (53a) is connected to the input port of the booster front buffer tank (33) through a pipeline.

9. The cyclic hydrogen storage and release system based on aromatic hydrocarbon cycloalkane reaction according to any one of claims 2, 3, 5 to 7, characterized in that: The adsorption and purification unit (40) includes an adsorption tower (41) and a desorption gas buffer tank (42), the gas phase output port of the fourth cooler (53d) is connected to the purified gas inlet of the adsorption tower (41) through a pipeline, and the purified gas outlet of the adsorption tower (41) is connected to the input port of the desorption gas buffer tank (42); The output port of the desorbed gas buffer tank (42) is connected to the input port pipeline of the aromatic hydrocarbon preheater (51) through a pipeline.

10. The cyclic hydrogen storage and release system based on aromatic hydrocarbon cycloalkane reaction according to claim 9, characterized in that: The adsorption tower (41) is a two-tower temperature-swing adsorption tower, the adsorbent filled inside of which is activated carbon, alumina or molecular sieve, including two towers A / B that work alternately for adsorption and desorption, and the desorption working temperature range is 150-350°C.

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