Hydrogen preparation and purification device and method

Abstract

The invention relates to the technical field of hydrogen production equipment, in particular to a hydrogen preparation and purification device and method. According to the hydrogen preparation and purification device, by arranging the deaerator, the pre-drying tower, the first drying tower, the second drying tower, the condenser, the flow regulator, the regeneration gas heater, the regeneration gas condenser and the multiple control valves, heating adsorption and condensation adsorption of hydrogen are achieved, hydrogen consumption is effectively reduced, and the good purification effect of hydrogen is guaranteed; as the hydrogen obtained by water electrolysis is pure and has low impurity content, the process route of removing impurity oxygen by adopting the hydrogen under the catalytic action of the palladium catalyst and then carrying out temperature swing adsorption dehydration by adopting the activated aluminum oxide and molecular sieve composite bed layer is reasonable, the process flow is simple, the energy consumption is low, and for small and medium-sized purification devices, system integration and skid-mounting are easy, and the cost is low. And the method can be widely applied to various industrial fields.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production equipment, and in particular to a hydrogen preparation and purification device and method. Background Art

[0002] As a clean energy, hydrogen has the advantages of high combustion heat and non-polluting combustion products. It is the most promising energy carrier to replace traditional fossil fuels and will occupy an important position in the future energy structure. Common hydrogen production methods include purification of by-products of the chlor-alkali industry, coal-to-hydrogen, natural gas steam reforming, methanol cracking, water electrolysis, biomass and other renewable energy sources.

[0003] As a new type of energy, hydrogen energy has many sources, that is, hydrogen production and supply methods, but all of them have various problems. The domestic and foreign markets have an urgent need for low-cost hydrogen supply.

[0004] At present, the general process flow of traditional alkaline water electrolysis for hydrogen production is: 25-30% potassium hydroxide or sodium hydroxide aqueous solution is used as the electrolyte, and the electrolyzer usually works at 80-90°C. Water is electrolyzed into H2 and O2 in the electrolyzer, and enters the hydrogen and oxygen liquid separators in the gas-liquid post-treatment device together with the un-electrolyzed alkaline solution. The separated gases are then washed and cooled. In the alkaline water electrolysis industry, oxygen is usually not used and is discharged into the atmosphere, while hydrogen is used. However, the hydrogen after the above simple treatment has a high dew point due to its high water content, which cannot meet the subsequent production requirements.

[0005] Therefore, in order to remove the moisture contained in the hydrogen, it is usually necessary to introduce a purification device. For example, patent number CN104627963B discloses a method for purifying hydrogen by electrolysis of water and a device for implementing the method. The entire purification process is that the electrolysis of water by hydrogen is carried out periodically and continuously in two drying towers, and each working cycle is divided into two stages: the raw hydrogen enters the first drying tower and the whole gas volume is dehumidified under the working pressure. The obtained high-purity hydrogen is divided into two parts, of which the product hydrogen enters the subsequent hydrogen use unit, and the regenerated hydrogen enters the second drying tower. After the working pressure in the second drying tower is released to normal pressure, the hydrogen absorbed by the second drying tower in the previous cycle is dehumidified. The attached moisture is blown to regenerate the desiccant inside the second drying tower. After blowing, the regenerated hydrogen is cooled and discharged; the other stage is similar to this. Hydrogen with a dew point as low as -80°C can be obtained through periodic purification. However, the device has the following problems: 1. Multiple one-way valves are used for hydrogen adsorption, cooling and regeneration, which makes it difficult to control the airflow and complicates the process; 2. Due to the lack of a tank to provide corresponding buffer, the one-way valve is often damaged by the impact of the switching instantaneous air pressure and needs to be replaced frequently, resulting in increased production costs. Summary of the invention

[0006] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a hydrogen preparation and purification device and method.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a hydrogen preparation and purification device, comprising a deoxidizer, a pre-drying tower, a first drying tower, and a second drying tower, the gas outlet of the deoxidizer is connected to a condenser, the condenser is connected to a water vapor separator, the gas outlet of the water vapor separator is connected to a flow regulator, the flow regulator is connected to a main pipeline and a regeneration gas pipeline, the main pipeline is connected to the first drying tower, the first drying tower is connected to a first control valve, the gas outlet of the first control valve is connected to an exhaust pipeline, and a dew point analyzer is installed on the exhaust pipeline; the regeneration gas pipeline is respectively connected to the pre-drying tower and the second drying tower, the pre-drying tower is connected to a regeneration gas heater, the regeneration gas heater is connected to the second drying tower, the second drying tower is connected to a second control valve, the second control valve is connected to a regeneration gas condenser, the regeneration gas condenser is connected to a regeneration gas water separator, and the regeneration gas water separator is connected to the main pipeline.

[0008] Furthermore, a third control valve is installed between the regeneration gas heater and the second drying tower.

[0009] Furthermore, a fourth control valve is installed between the regeneration gas pipeline and the pre-drying tower, the first drying tower, and the second drying tower respectively.

[0010] Furthermore, a fifth control valve is installed between the pre-drying tower and the regeneration gas condenser.

[0011] Furthermore, heaters are provided in the deoxidizer, the pre-drying tower, the first drying tower and the second drying tower.

[0012] Furthermore, the pre-drying tower, the first drying tower and the second drying tower are all filled with a composite bed of activated alumina and molecular sieves, and the composite bed is used to adsorb moisture in the hydrogen to dry the hydrogen.

[0013] Furthermore, the deoxidizer is filled with a palladium catalyst, which is used to catalyze a chemical reaction between oxygen and hydrogen to generate water.

[0014] Furthermore, a pressure controller is installed on the exhaust pipe.

[0015] A method for preparing and purifying hydrogen, using the above-mentioned hydrogen preparation and purification device, the method is as follows:

[0016] S1, the crude hydrogen prepared by the hydrogen production equipment enters the deoxidizer for deoxygenation treatment, and then enters the condenser for condensation to preliminarily remove moisture from the hydrogen;

[0017] S2. Adjust the flow rate of the flow regulator so that 80-85% of the hydrogen passes through the first drying tower on the main pipeline for drying, and 15-20% of the hydrogen enters the pre-drying tower through the regeneration pipeline, and after drying, enters the regeneration gas heater to be heated to 160°C, and then enters the second drying tower against the adsorption direction to wash the adsorbent, so that the outlet temperature of the second drying is higher than 120°C; the desorbed water is discharged with the air flow, condensed to 35°C through the regeneration gas condenser, and then separated by the regeneration gas water separator and returned to the main pipeline, and merged with the hydrogen on the original main pipeline into the first drying tower for drying;

[0018] S3. The hydrogen dried in the first drying tower flows out from the first control valve and is sent to the subsequent process section after being monitored by the pressure controller and the online dew point analyzer and found to be qualified.

[0019] Furthermore, it also includes condensation adsorption. After the heating is completed, 15-20% of the hydrogen is distributed through the flow regulator to flush the adsorbent in the direction of adsorption, so that it is condensed to below 40°C; the gas coming out of the second dryer is heated to 160°C by the regeneration gas heater and then enters the pre-dryer, and then condensed to 35°C by the regeneration gas condenser, and then passes through the regeneration gas water separator to separate the water and return to the main pipeline, and re-enters the first drying tower for drying.

[0020] Compared with the prior art, the technical solution of this application has the following beneficial effects:

[0021] 1. The present application realizes heating adsorption and condensation adsorption of hydrogen by setting a deoxidizer, a pre-drying tower, a first drying tower, a second drying tower, a condenser, a flow regulator, a regeneration gas heater, a regeneration gas condenser, and several control valves, thereby effectively reducing hydrogen consumption and ensuring a good hydrogen purification effect; and the setting of three tower bodies can provide a good buffering effect during the heating adsorption and condensation adsorption process, ensuring a long service life of each control valve.

[0022] 2. In this application, since the hydrogen obtained by water electrolysis is relatively pure and has a low impurity content, it is more reasonable to use hydrogen to remove impurity oxygen under the catalytic action of palladium catalyst, and then use activated alumina and molecular sieve composite bed for temperature-swing adsorption dehydration. The process route is simple and has low energy consumption. It is easy to integrate the system into the skid for small and medium-sized purification devices, saving space and investment, and can be widely used in various industrial fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of heating adsorption of a hydrogen preparation and purification device in a preferred embodiment of the present invention;

[0024] Figure 2 It is a schematic diagram of the structure of condensation adsorption of the hydrogen preparation and purification device in the preferred embodiment of the present invention.

[0025] Figure numerals: 1. deoxygenator; 2. pre-drying tower; 3. first drying tower; 4. second drying tower; 5. condenser; 6. water vapor separator; 7. flow regulator; 8. main pipeline; 9. regeneration gas pipeline; 10. regeneration gas heater; 11. first control valve; 12. exhaust pipeline; 13. dew point analyzer; 14. second control valve; 15. regeneration gas condenser; 16. regeneration gas water separator; 17. third control valve; 18. fourth control valve; 19. fifth control valve; 20. pressure controller. DETAILED DESCRIPTION

[0026] The technical solutions in the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0027] Reference Figure 1 As shown, a preferred embodiment of the present invention is a hydrogen preparation and purification device, comprising a deoxidizer 1, a pre-drying tower 2, a first drying tower 3, and a second drying tower 4, wherein the gas outlet of the deoxidizer 1 is connected to a condenser 5, the condenser 5 is connected to a water vapor separator 6, the gas outlet of the water vapor separator 6 is connected to a flow regulator 7, the flow regulator 7 is connected to a main pipeline 8 and a regeneration gas pipeline 9, the main pipeline 8 is connected to the first drying tower 3, the first drying tower 3 is connected to a first control valve 11, the gas outlet of the first control valve 11 is connected to an exhaust pipeline 12, and a dew point analyzer 13 is installed on the exhaust pipeline 12; the regeneration gas pipeline 9 is respectively connected to A pre-drying tower 2 and a second drying tower 4, wherein the pre-drying tower 2 is connected with a regeneration gas heater 10, wherein the regeneration gas heater 10 is connected with the second drying tower 4, wherein the second drying tower 4 is connected with a second control valve 14, wherein the second control valve 14 is connected with a regeneration gas condenser 15, wherein the regeneration gas condenser 15 is connected with a regeneration gas water separator 16, wherein the regeneration gas water separator 16 is connected with the main pipeline 8, thereby realizing heating adsorption and condensation adsorption of hydrogen, effectively reducing hydrogen consumption, and ensuring a good purification effect of hydrogen; and the arrangement of the three tower bodies can provide a good buffering effect during the heating adsorption and condensation adsorption process, thereby ensuring a long service life of each control valve.

[0028] As a preferred embodiment of the present invention, it may also have the following additional technical features: a third control valve 17 is installed between the regeneration gas heater 10 and the second drying tower 4; a fourth control valve 18 is installed between the regeneration gas pipeline 9 and the pre-drying tower 2, the first drying tower 3, and the second drying tower 4; a fifth control valve 19 is installed between the pre-drying tower 2 and the regeneration gas condenser 15. Thus, it is convenient to control the heating adsorption and condensation adsorption of hydrogen, effectively reduce hydrogen consumption, and ensure a good hydrogen purification effect.

[0029] In this embodiment, heaters are provided in the deoxidizer 1, the pre-drying tower 2, the first drying tower 3, and the second drying tower 4. Thus, the purification of hydrogen can be achieved by controlling the working conditions of the heaters in the deoxidizer 1, the pre-drying tower 2, the first drying tower 3, and the second drying tower 4.

[0030] In this embodiment, the pre-drying tower 2, the first drying tower 3, and the second drying tower 4 are all filled with a composite bed of activated alumina and molecular sieves, and the composite bed is used to absorb water in hydrogen and dry the hydrogen; and the deoxidizer 1 is filled with a palladium catalyst, and the palladium catalyst is used to catalyze the chemical reaction between oxygen and hydrogen to generate water. Since the hydrogen obtained by water electrolysis is relatively pure and has a low impurity content, it is more reasonable to use hydrogen to remove impurity oxygen under the catalytic action of palladium catalyst, and then use activated alumina and molecular sieve composite beds for temperature swing adsorption dehydration. The process route is short and energy consumption is low. It is easy to integrate the system into skids for small and medium-sized purification devices, saving land and investment, and can be widely used in various industrial fields.

[0031] In this embodiment, a pressure controller 20 is installed on the exhaust pipe 12. Thus, it is convenient for the user to observe the pressure information of the entire device.

[0032] like Figure 1 As shown, a method for preparing and purifying hydrogen, using the above-mentioned hydrogen preparation and purification device, the method is as follows:

[0033] S1, the crude hydrogen prepared by the hydrogen production equipment enters the deoxidizer 1 for deoxidation treatment, and then enters the condenser 5 for condensation to preliminarily remove water from the hydrogen;

[0034] S2. Adjust the flow rate of the flow regulator 7 so that 80-85% of the hydrogen passes through the first drying tower 3 on the main pipeline 8 for drying, and 15-20% of the hydrogen enters the pre-drying tower 2 through the regeneration pipeline 9, and enters the regeneration gas heater 10 after drying to be heated to 160°C, and then enters the second drying tower 4 in the opposite direction of adsorption to wash the adsorbent, so that the outlet temperature of the second drying tower 4 is higher than 120°C. If it fails to meet the requirements, the regeneration gas volume should be increased or the heating time should be extended to ensure that the adsorbent is completely regenerated; in actual operation, when the water content exceeds the standard, while increasing the regeneration gas volume, the flow rate of the regenerator heater steam and the drying tower outlet temperature should also be increased to ensure that the product hydrogen dew point is qualified;

[0035] The desorbed water is discharged with the air flow and condensed to 35°C through the regeneration gas condenser 15. If the requirement is not met within the specified time, the cooling time should be extended, otherwise the drying effect during adsorption will be reduced; the water is separated by the regeneration gas water separator 16 and then returned to the main pipeline 8, and merged with the hydrogen on the original main pipeline 8 to enter the first drying tower 3 for drying;

[0036] S3. The hydrogen dried in the first drying tower 3 flows out from the first control valve 11, and is sent to the subsequent process section after being monitored by the pressure controller 20 and the online dew point analyzer 13 to be qualified, thereby achieving heating, drying and purification of the hydrogen and ensuring a lower dew point of the hydrogen.

[0037] like Figure 2 As shown, in this embodiment, condensation adsorption is also included. After the heating is completed, 15-20% of the hydrogen is distributed through the flow regulator 7 to wash the adsorbent in the direction of adsorption, so that it is condensed to below 40°C; the gas coming out of the second dryer 4 is heated to 160°C by the regeneration gas heater 10 and then enters the pre-dryer 2, and then condensed to 35°C by the regeneration gas condenser 16, and then passes through the regeneration gas water separator 16 to separate the water and return to the main pipeline, and re-enters the first drying tower 2 for drying, thereby realizing the condensation, drying and purification of hydrogen.

[0038] The present invention obtains relatively pure hydrogen with less impurities by electrolyzing water. The impurity oxygen is removed by hydrogen under the catalytic action of palladium catalyst, and then activated alumina and molecular sieve composite bed are used for temperature-swing adsorption dehydration. The process route is relatively reasonable. The process flow is short and the energy consumption is low. It is easy to integrate the system into the skid for small and medium-sized purification devices, saving land and investment, and can be widely used in various industrial fields.

[0039] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0040] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A hydrogen preparation and purification device, comprising a deoxidizer, a pre-drying tower, a first drying tower, and a second drying tower, characterized in that: The deoxidizer is connected to a condenser at its gas outlet, a water vapor separator is connected to the condenser, a flow regulator is connected to the gas outlet of the water vapor separator, a main pipeline and a regeneration gas pipeline are connected to the flow regulator, the main pipeline is connected to the first drying tower, the first drying tower is connected to a first control valve, the gas outlet of the first control valve is connected to an exhaust pipeline, and a dew point analyzer is installed on the exhaust pipeline; the regeneration gas pipeline is respectively connected to a pre-drying tower and a second drying tower, the pre-drying tower is connected to a regeneration gas heater, the regeneration gas heater is connected to the second drying tower, the second drying tower is connected to a second control valve, the second control valve is connected to a regeneration gas condenser, the regeneration gas condenser is connected to a regeneration gas water separator, and the regeneration gas water separator is communicated with the main pipeline.

2. The hydrogen preparation and purification device according to claim 1, characterized in that: A third control valve is installed between the regeneration gas heater and the second drying tower.

3. The hydrogen preparation and purification device according to claim 2, characterized in that: A fourth control valve is installed between the regeneration gas pipeline and the pre-drying tower, the first drying tower, and the second drying tower.

4. The hydrogen preparation and purification device according to claim 3, characterized in that: A fifth control valve is installed between the pre-drying tower and the regeneration gas condenser.

5. The hydrogen preparation and purification device according to claim 1, characterized in that: The deoxidizer, the pre-drying tower, the first drying tower and the second drying tower are all provided with heaters.

6. The hydrogen preparation and purification device according to claim 1, characterized in that: The pre-drying tower, the first drying tower and the second drying tower are all filled with a composite bed of activated alumina and molecular sieves, and the composite bed is used to absorb moisture in the hydrogen to dry the hydrogen.

7. The hydrogen preparation and purification device according to claim 1, characterized in that: The deoxidizer is filled with a palladium catalyst, and the palladium catalyst is used to catalyze the chemical reaction between oxygen and hydrogen to generate water.

8. The hydrogen preparation and purification device according to claim 1, characterized in that: A pressure controller is installed on the exhaust pipe.

9. A method for preparing and purifying hydrogen, characterized in that: The hydrogen preparation and purification device according to any one of claims 1 to 8 is used, and the method is as follows: S1, the crude hydrogen prepared by the hydrogen production equipment enters the deoxidizer for deoxygenation treatment, and then enters the condenser for condensation to preliminarily remove moisture from the hydrogen; S2. Adjust the flow rate of the flow regulator so that 80-85% of the hydrogen passes through the first drying tower on the main pipeline for drying, and 15-20% of the hydrogen enters the pre-drying tower through the regeneration pipeline, and after drying, enters the regeneration gas heater to be heated to 160°C, and then enters the second drying tower against the adsorption direction to wash the adsorbent, so that the outlet temperature of the second drying is higher than 120°C; the desorbed water is discharged with the air flow, condensed to 35°C through the regeneration gas condenser, and then separated by the regeneration gas water separator and returned to the main pipeline, and merged with the hydrogen on the original main pipeline into the first drying tower for drying; S3. The hydrogen dried in the first drying tower flows out from the first control valve and is sent to the subsequent process section after being monitored by the pressure controller and the online dew point analyzer and found to be qualified.

10. The method for preparing and purifying hydrogen according to claim 9, characterized in that: It also includes condensation adsorption. When the heating is completed, 15-20% of the hydrogen is distributed through the flow regulator to flush the adsorbent in the direction of adsorption, so that it is condensed to below 40°C; the gas coming out of the second dryer is heated to 160°C by the regeneration gas heater and then enters the pre-dryer, and then condensed to 35°C by the regeneration gas condenser, and then passes through the regeneration gas water separator to separate the water and return to the main pipeline, and re-enters the first drying tower for drying.

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