Water vapor hydrogen production system and method, hydrogen purification system and method

Abstract

This application discloses a steam hydrogen production system and method, and a hydrogen purification system and method. The hydrogen purification system includes a first water removal subsystem, a second water removal subsystem, an alkaline washing device, and a drying device connected in sequence. The first water removal subsystem separates condensate from water-containing hydrogen to obtain product hydrogen. The second water removal subsystem separates residual condensate from the product hydrogen to obtain secondary purified hydrogen. The alkaline washing device removes carbon dioxide from the secondary purified hydrogen to obtain tertiary purified hydrogen. The drying device dries the tertiary purified hydrogen to obtain the target product hydrogen. The technical solution provided by this application can produce high-purity hydrogen.

Description

Technical Field

[0001] This application belongs to the field of hydrogen production and purification technology, and particularly relates to a steam hydrogen production system and method, and a hydrogen purification system and method. Background Technology

[0002] Currently, hydrogen is a widely available, clean, efficient, and versatile secondary energy source. It serves as a crucial link between renewable energy production and green energy end-use, and is considered the most ideal clean energy carrier for the future. Furthermore, as an important raw material for the raw materials industry, hydrogen is also a vital driver of low-carbon development in traditional industries. Therefore, the quality of hydrogen is extremely important in industrial production, and hydrogen purity is a key indicator for evaluating its quality. Consequently, improving hydrogen purity is a pressing issue that needs to be addressed. Summary of the Invention

[0003] The embodiments of this application provide a steam hydrogen production system and method, and a hydrogen purification system and method, which can improve the purity of hydrogen.

[0004] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0005] According to a first aspect of the embodiments of this application, a steam hydrogen production system is provided, characterized in that the system includes a steam supply subsystem, a decomposition reaction subsystem, and a separation subsystem connected in sequence, wherein: the steam supply subsystem is used to provide a preset flow rate of steam to the decomposition reaction subsystem; the decomposition reaction subsystem is used to perform a steam decomposition hydrogen production reaction; and the separation subsystem is used to separate the steam from the hydrogen produced by the decomposition reaction subsystem to obtain product hydrogen.

[0006] In some embodiments of this application, based on the foregoing scheme, the water vapor supply subsystem includes: a water vapor source for providing impurity-containing water vapor; a first separator connected to the water vapor source via a pipeline for separating liquid water and impurities from the impurity-containing water vapor to obtain water vapor; and a water vapor flow controller connected to the first separator via a pipeline for adjusting the flow rate of the water vapor to a preset flow rate.

[0007] In some embodiments of this application, based on the foregoing scheme, the decomposition reaction subsystem includes: a reactor connected to the steam flow controller via a pipeline for performing a steam decomposition reaction to produce hydrogen containing water; a differential pressure gauge connected to the inlet and outlet of the reactor via pipelines respectively for detecting the pressure difference between the inlet and outlet of the reactor; and a first pressure controller connected to the reactor via a pipeline for controlling the pressure of the reactor to remain stable.

[0008] In some embodiments of this application, based on the foregoing scheme, the separation subsystem includes: a first cooler connected to the first pressure controller via a pipeline for heat exchange between the water-containing hydrogen and air; a second cooler connected to the first cooler via a pipeline for heat exchange between the water-containing hydrogen and a coolant; a second separator connected to the second cooler via a pipeline for separating condensate from the water-containing hydrogen to obtain product hydrogen; and a second pressure controller connected to the second separator via a pipeline for controlling the pressure of the separation subsystem to remain stable.

[0009] In some embodiments of this application, based on the foregoing scheme, the second separator is provided with a first liquid level controller for controlling the condensate level in the second separator.

[0010] In some embodiments of this application, based on the foregoing scheme, the system further includes a first pressurizer connected to the second pressure controller via a pipeline, for pressurizing the product hydrogen to a preset pressure.

[0011] According to a second aspect of the embodiments of this application, a method for producing hydrogen from water vapor is provided, characterized in that it is executed by a system as described in any of the first aspects above, the method comprising: controlling a water vapor source to pass impurity-containing water vapor into a first separator, and separating liquid water and impurities from the impurity-containing water vapor through the first separator to obtain water vapor; adjusting the water vapor to a preset flow rate through a water vapor flow controller, and then passing it into a reactor to carry out a water vapor decomposition hydrogen production reaction to obtain water-containing hydrogen gas; passing the water-containing hydrogen gas sequentially into a first cooler and a second cooler, respectively exchanging heat with air and a coolant to cool the water-containing hydrogen gas, and passing the cooled water-containing hydrogen gas into a second separator, and separating the condensate from the water-containing hydrogen gas through the second separator to obtain product hydrogen gas.

[0012] In some embodiments of this application, based on the foregoing scheme, the method further includes: during the water vapor decomposition hydrogen production reaction, controlling the pressure of the reactor to remain stable through a first pressure controller; and during the cooling and temperature reduction of the water-containing hydrogen gas, controlling the pressure of the separation subsystem to remain stable through a second pressure controller.

[0013] In some embodiments of this application, based on the foregoing scheme, the method further includes: when the condensate level in the second separator is higher than the first preset level, controlling the first level controller to open the drain outlet of the second separator to discharge the condensate; when the condensate level in the second separator is lower than the second preset level, controlling the first level controller to close the drain outlet of the second separator to stop discharging the condensate, wherein the first preset level is higher than the second preset level.

[0014] In some embodiments of this application, based on the aforementioned scheme, the preset flow rate is positively correlated with the planned hydrogen production.

[0015] Based on the technical solution proposed in this application, by passing impurity-containing water vapor into the first separator, liquid water and impurities in the water vapor can be removed, thereby improving the purity of the water vapor and avoiding the influence of impurities on the water vapor decomposition hydrogen production reaction, thus improving the purity of the hydrogen produced by the water vapor decomposition reaction. By adjusting the flow rate of the water vapor to a preset flow rate through a water vapor flow controller before passing it into the reactor, the water vapor in the reactor can fully react, which can not only increase the hydrogen production but also reduce the water vapor content in the produced hydrogen, thereby improving the purity of the hydrogen produced by the water vapor decomposition reaction. By passing the water-containing hydrogen gas sequentially into the first cooler and the second cooler, where it exchanges heat with air and coolant respectively, the water-containing hydrogen gas can be fully cooled, thereby allowing the water vapor contained in the water-containing hydrogen gas to be fully condensed into condensate, facilitating the separation of hydrogen gas and condensate, and further improving the purity of hydrogen gas.

[0016] According to a third aspect of the embodiments of this application, a hydrogen purification system is provided, characterized in that the system includes a first water removal subsystem, a second water removal subsystem, an alkaline washing device, and a drying device connected in sequence, wherein the first water removal subsystem is used to separate condensate from water-containing hydrogen to obtain product hydrogen; the second water removal subsystem is used to separate the remaining condensate from the product hydrogen to obtain secondary purified hydrogen; the alkaline washing device is used to remove carbon dioxide from the secondary purified hydrogen to obtain tertiary purified hydrogen; and the drying device is used to dry the tertiary purified hydrogen to obtain the target product hydrogen.

[0017] In some embodiments of this application, based on the aforementioned scheme, the first water removal subsystem includes: a third cooler for heat exchange between the water-containing hydrogen and air; a fourth cooler connected to the third cooler via a pipeline for heat exchange between the water-containing hydrogen and a coolant; and a third separator connected to the fourth cooler via a pipeline for separating condensate from the water-containing hydrogen to obtain product hydrogen.

[0018] In some embodiments of this application, based on the foregoing scheme, the second water removal subsystem includes: a second pressurizer connected to the third separator via a pipeline for pressurizing the product hydrogen; a fifth cooler connected to the second pressurizer via a pipeline for heat exchange between the pressurized product hydrogen and the coolant; and a fourth separator connected to the fifth cooler via a pipeline for separating condensate from the product hydrogen to obtain secondary purified hydrogen.

[0019] In some embodiments of this application, based on the foregoing scheme, the third separator and the fourth separator are respectively provided with a second liquid level controller and a third liquid level controller for controlling the condensate liquid level in the third separator and the fourth separator.

[0020] In some embodiments of this application, based on the foregoing scheme, the drying device is equipped with a solid desiccant for absorbing residual water vapor in the tertiary purified hydrogen.

[0021] In some embodiments of this application, based on the foregoing scheme, the system further includes a third pressure controller for controlling the pressure of the hydrogen purification system to remain stable.

[0022] According to a fourth aspect of the embodiments of this application, a method for purifying hydrogen is provided, characterized in that it is executed by a system as described in any of the third aspects above, the method comprising: sequentially passing water-containing hydrogen into a third cooler and a fourth cooler, exchanging heat with air and a coolant respectively to cool the water-containing hydrogen; passing the cooled water-containing hydrogen into a third separator to separate condensate from the water-containing hydrogen to obtain product hydrogen; passing the product hydrogen into a second pressurizer for pressurization, and then passing the pressurized product hydrogen into a third separator. In the fifth cooler, heat exchange occurs with the coolant, causing uncondensed water vapor in the product hydrogen to condense into condensate, resulting in water-containing product hydrogen. This water-containing product hydrogen is then passed into the fourth separator to separate the condensate, yielding secondary purified hydrogen. The secondary purified hydrogen is then passed into an alkaline washing device for alkaline washing to remove carbon dioxide, resulting in tertiary purified hydrogen. Finally, the tertiary purified hydrogen is passed into a drying device to remove residual water vapor, yielding the target product hydrogen.

[0023] In some embodiments of this application, based on the foregoing scheme, the method further includes: during the hydrogen purification process, controlling the pressure of the hydrogen purification system to remain stable through a third pressure controller.

[0024] In some embodiments of this application, based on the foregoing scheme, the method further includes: when the condensate level in the third separator is higher than the first preset level, controlling the second level controller to open the drain outlet of the third separator to discharge the condensate; when the condensate level in the third separator is lower than the second preset level, controlling the second level controller to close the drain outlet of the third separator to stop discharging the condensate, wherein the first preset level is higher than the second preset level; when the condensate level in the fourth separator is higher than the first preset level, controlling the third level controller to open the drain outlet of the fourth separator to discharge the condensate; when the condensate level in the fourth separator is lower than the second preset level, controlling the third level controller to close the drain outlet of the fourth separator to stop discharging the condensate.

[0025] Based on the technical solutions proposed in this application, firstly, by sequentially passing the water-containing hydrogen gas into the third and fourth coolers for heat exchange with air and coolant respectively, the water-containing hydrogen gas can be sufficiently cooled, allowing the water vapor contained in the water-containing hydrogen gas to be fully condensed into condensate, facilitating the separation of hydrogen gas and condensate, and improving the purity of hydrogen gas. Secondly, by pressurizing the product hydrogen gas and then cooling the pressurized product hydrogen gas, the uncondensed water vapor in the product hydrogen gas can be condensed into condensate, and the condensate is separated by the fourth separator, further improving the purity of hydrogen gas. Thirdly, by setting up a drying device, the water vapor that cannot be completely condensed in the three-stage purified hydrogen gas can be absorbed, as well as the water vapor carried out by the hydrogen gas from the alkaline washing device, which can further improve the purity of hydrogen gas.

[0026] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0028] Figure 1 A schematic diagram of a steam hydrogen production system in one embodiment of this application is shown;

[0029] Figure 2 A flowchart of a method for producing hydrogen from water vapor in one embodiment of this application is shown;

[0030] Figure 3A schematic diagram of a hydrogen purification system in one embodiment of this application is shown;

[0031] Figure 4 A flowchart of a hydrogen purification method according to one embodiment of this application is shown.

[0032] The annotations in the attached figures are explained as follows:

[0033] 1. Steam source; 2. First separator;

[0034] 3. Steam flow controller; 4. Reactor;

[0035] 5. Differential pressure gauge; 6. First pressure controller;

[0036] 7. First cooler; 8. Second cooler;

[0037] 9. First liquid level controller; 10. Second separator;

[0038] 11. Second pressure controller; 12. First pressure booster;

[0039] 13. Third cooler; 14. Fourth cooler;

[0040] 15. Third separator; 16. Second liquid level controller;

[0041] 17. Second pressurizer; 18. Fifth cooler;

[0042] 19. Fourth separator; 20. Third level controller;

[0043] 21. Alkali washing device 22. Drying device

[0044] 23. Third pressure controller Detailed Implementation

[0045] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0047] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0048] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0049] It should also be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such uses of these terms can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described.

[0050] To enable those skilled in the art to better understand this solution, firstly, in conjunction with Figure 1 The steam hydrogen production system proposed in this application is described in detail.

[0051] See Figure 1 The diagram shows a schematic of a steam hydrogen production system in one embodiment of this application.

[0052] like Figure 1 As shown, the steam hydrogen production system may include at least a steam supply subsystem A, a decomposition reaction subsystem B, and a separation subsystem C. The steam supply subsystem A may include at least a steam source 1, a first separator 2, and a steam flow controller 3. The steam source 1 can be used to provide steam containing impurities. The first separator 2 is connected to the steam source 1 through a pipeline and can be used to separate liquid water and impurities from the steam containing impurities to obtain steam. The steam flow controller 3 is connected to the first separator 2 through a pipeline and can be used to adjust the flow rate of the steam to a preset flow rate.

[0053] In this application, the preset flow rate can be determined based on the planned hydrogen production, that is, the preset flow rate is positively correlated with the planned hydrogen production. Specifically, for example, the planned hydrogen production is 1000 Nm³. 3 If the preset flow rate is 2t / h, then the planned hydrogen production and the preset flow rate can be other parameters as needed. This application does not make any specific limitations on this.

[0054] In this application, the first separator 2 separates liquid water and impurities from the water vapor containing impurities, which can improve the purity of the water vapor and avoid the influence of impurities on the water vapor decomposition hydrogen production reaction. This can improve the purity of the hydrogen produced by the water vapor decomposition reaction. In addition, by adjusting the water vapor flow rate to the preset flow rate by the water vapor flow controller 3, it can be ensured that the water vapor can react fully, thereby further improving the purity of the hydrogen produced by water vapor decomposition.

[0055] Continue to refer to Figure 1 The decomposition reaction subsystem B may specifically include a reactor 4, a differential pressure gauge 5, and a first pressure controller 6. The reactor 4 is connected to the steam flow controller 3 via a pipeline and can be used to perform a steam decomposition reaction to produce hydrogen containing water. The differential pressure gauge 5 is connected to the inlet and outlet of the reactor 4 via pipelines and can be used to detect the pressure difference between the inlet and outlet of the reactor 4. The first pressure controller 6 is connected to the reactor 4 via a pipeline and can be used to control the pressure of the reactor 4 to remain stable.

[0056] In this application, the steam decomposition hydrogen production reaction can specifically use a metal cracking catalyst. By catalyzing the steam decomposition hydrogen production reaction with the metal cracking catalyst, the conversion rate of steam can be improved, thereby increasing the hydrogen production. In addition, the improved steam conversion rate can also reduce the water vapor content in the hydrogen produced by the steam decomposition hydrogen production reaction, thereby improving the purity of the hydrogen produced by steam decomposition.

[0057] In this application, a differential pressure gauge 5 is used to detect the pressure difference between the inlet and outlet of the reactor 4. This pressure difference allows for the determination of whether the catalyst for the steam decomposition hydrogen production reaction has deactivated and whether it needs to be replaced. This ensures that the catalyst for the steam decomposition hydrogen production reaction remains in a good catalytic state, thereby improving the steam conversion rate and the purity of the hydrogen produced by steam decomposition.

[0058] Continue to refer to Figure 1The separation subsystem C specifically includes a first cooler 7, a second cooler 8, a second separator 10, and a second pressure controller 11. The first cooler 7 is connected to the first pressure controller via a pipe and is used for heat exchange between the water-containing hydrogen and air. The second cooler 8 is connected to the first cooler via a pipe and is used for heat exchange between the water-containing hydrogen and a coolant. The second separator 10 is connected to the second cooler via a pipe and is used to separate condensate from the water-containing hydrogen to obtain product hydrogen. The second pressure controller 11 is connected to the second separator via a pipe and is used to control the pressure of the separation subsystem to maintain stability.

[0059] In this application, the first cooler 7 can specifically be an air cooler, that is, it exchanges heat with the water-containing hydrogen by compressing air through a turbine, so as to initially cool the water-containing hydrogen and cause some of the water vapor in the water-containing hydrogen to condense; the second cooler 8 can specifically be a water cooler, and the coolant can specifically be cooling water, so as to further cool the water-containing hydrogen and cause most of the water vapor in the water-containing hydrogen to condense into condensate for separation, thereby improving the purity of hydrogen produced by water vapor decomposition.

[0060] In this application, the second separator 10 may be equipped with a first liquid level controller 9 to control the condensate level in the second separator 10, thereby improving the efficiency of hydrogen and condensate separation. At the same time, it can also prevent hydrogen leakage during the hydrogen and condensate separation process, ensuring the airtightness of the steam hydrogen production system, thereby improving the purity of hydrogen produced by steam decomposition.

[0061] Continue to refer to Figure 1 The steam hydrogen production system may also include a first pressurizer 12, which is connected to the second pressure controller via a pipeline, and can be used to pressurize the product hydrogen to a preset pressure for user use.

[0062] Next, in order to enable those skilled in the art to better understand this application, we will combine... Figure 2 The method for producing hydrogen from steam proposed in this application is described in detail.

[0063] See Figure 2 The figure shows a flowchart of a method for producing hydrogen from steam according to one embodiment of this application. As shown, the method for producing hydrogen from steam may include at least the following steps 210 to 230:

[0064] Step 210: Control the water vapor source to pass the impurity-containing water vapor into the first separator, and separate the liquid water and impurities in the impurity-containing water vapor through the first separator to obtain water vapor.

[0065] Step 220: After adjusting the water vapor to a preset flow rate using a water vapor flow controller, the water vapor is introduced into the reactor to carry out the water vapor decomposition hydrogen production reaction, and water-containing hydrogen gas is obtained.

[0066] Step 230: The water-containing hydrogen gas is sequentially passed into the first cooler and the second cooler to exchange heat with air and coolant respectively, thereby cooling the water-containing hydrogen gas. The cooled water-containing hydrogen gas is then passed into the second separator to separate the condensate from the water-containing hydrogen gas, thereby obtaining product hydrogen gas.

[0067] In this application, by introducing impurity-containing water vapor into the first separator, liquid water and impurities in the water vapor can be removed, thereby improving the purity of the water vapor and avoiding the influence of impurities on the water vapor decomposition hydrogen production reaction, thus improving the purity of the hydrogen produced by the water vapor decomposition reaction. In addition, by adjusting the flow rate of the water vapor to a preset flow rate through a water vapor flow controller before introducing it into the reactor, the water vapor in the reactor can react fully, which can not only increase the hydrogen production but also reduce the water vapor content in the produced hydrogen, thereby improving the purity of the hydrogen produced by the water vapor decomposition reaction.

[0068] In this application, by sequentially passing the water-containing hydrogen gas into the first cooler and the second cooler, and exchanging heat with the air and the coolant respectively, the water-containing hydrogen gas can be sufficiently cooled, thereby allowing the water vapor contained in the water-containing hydrogen gas to be fully condensed into condensate, which facilitates the separation of hydrogen gas and condensate and can further improve the purity of hydrogen gas.

[0069] In the water vapor decomposition method for hydrogen production proposed in this application, the method may further perform the following steps 240 to 250:

[0070] Step 240: When the condensate level in the second separator is higher than the first preset level, control the first level controller to open the drain port of the second separator to discharge the condensate.

[0071] Step 250: When the condensate level in the second separator is lower than the second preset level, the first level controller is controlled to close the drain outlet of the second separator and stop discharging condensate. The first preset level is higher than the second preset level.

[0072] In this application, the discharge of condensate is controlled according to the condensate level in the second separator. When the condensate level in the second separator is higher than the first preset level, the first level controller opens the drain outlet of the second separator to discharge the condensate. This avoids the condensate level in the second separator being too high, which would affect the efficiency of hydrogen-condensate separation. When the condensate level in the second separator is lower than the second preset level, the first level controller closes the drain outlet of the second separator to stop the discharge of condensate. This prevents the condensate in the second separator from being directly drained, which not only prevents hydrogen leakage from the drain outlet from reducing the yield, but also prevents outside air from entering the drain outlet and reducing the purity of the hydrogen. Thus, the purity of the hydrogen prepared by the steam decomposition reaction can be ensured.

[0073] Based on the technical solution proposed in this application, by passing impurity-containing water vapor into the first separator, liquid water and impurities in the water vapor can be removed, thereby improving the purity of the water vapor and avoiding the influence of impurities on the water vapor decomposition hydrogen production reaction, thus improving the purity of the hydrogen produced by the water vapor decomposition reaction. By adjusting the flow rate of the water vapor to a preset flow rate through a water vapor flow controller before passing it into the reactor, the water vapor in the reactor can fully react, which can not only increase the hydrogen production but also reduce the water vapor content in the produced hydrogen, thereby improving the purity of the hydrogen produced by the water vapor decomposition reaction. By passing the water-containing hydrogen gas sequentially into the first cooler and the second cooler, where it exchanges heat with air and coolant respectively, the water-containing hydrogen gas can be fully cooled, thereby allowing the water vapor contained in the water-containing hydrogen gas to be fully condensed into condensate, facilitating the separation of hydrogen gas and condensate, and further improving the purity of hydrogen gas.

[0074] Based on the technical solution proposed in this application, the purity of the hydrogen produced by the decomposition reaction of water vapor can be applied to most production scenarios. However, in some production scenarios, hydrogen with higher purity is required. Therefore, in order to meet a wider range of production needs, the inventors of this application also propose a hydrogen purification system and method to further improve the purity of hydrogen.

[0075] To enable those skilled in the art to better understand the hydrogen purification system, the following will be combined with... Figure 3 The hydrogen purification system is described in detail below.

[0076] It should be noted that the hydrogen purification system can be used to further purify the hydrogen produced by the steam hydrogen production system. Specifically, the hydrogen purification system can be used in conjunction with, for example, the hydrogen produced by the steam hydrogen production system. Figure 1 The decomposition reaction subsystem B shown can be used to purify the hydrogen produced by said decomposition reaction subsystem B. See also... Figure 3The diagram shows a schematic of a hydrogen purification system in one embodiment of this application.

[0077] like Figure 3 As shown, the hydrogen purification system may include at least a first water removal subsystem D, a second water removal subsystem E, an alkaline washing device 21, and a drying device 22. The first water removal subsystem D may include at least a third cooler 13, a fourth cooler 14, a third separator 15, and a second liquid level controller 16. The third cooler 13 is used for heat exchange between the water-containing hydrogen and air. The fourth cooler 14, connected to the third cooler 13 via a pipe, is used for heat exchange between the water-containing hydrogen and a coolant. The third separator 15, connected to the fourth cooler 14 via a pipe, is used to separate condensate from the water-containing hydrogen to obtain product hydrogen.

[0078] In this application, the third cooler 13 can specifically be an air cooler, that is, it exchanges heat with the water-containing hydrogen through air to initially cool the water-containing hydrogen, thereby causing some of the water vapor in the water-containing hydrogen to condense; the fourth cooler 14 can specifically be a water cooler, and the coolant can specifically be cooling water, which further cools the water-containing hydrogen, thereby causing most of the water vapor in the water-containing hydrogen to condense into condensate for separation, thereby improving the purity of hydrogen produced by water vapor decomposition.

[0079] In this application, the third separator 15 is equipped with a second liquid level controller 16 to control the condensate level in the third separator 15, thereby improving the efficiency of hydrogen and condensate separation. At the same time, it can also prevent hydrogen leakage during the hydrogen and condensate separation process, ensuring the airtightness of the steam hydrogen production system, thereby improving the purity of hydrogen produced by steam decomposition.

[0080] Continue to refer to Figure 3 The second water removal subsystem E may include at least a second pressurizer 17, a fifth cooler 18, a fourth separator 19, and a third level controller 20. The second pressurizer 17 is connected to the third separator 15 via a pipeline and is used to pressurize the product hydrogen. The fifth cooler 18 is connected to the second pressurizer 17 via a pipeline and is used for heat exchange between the pressurized product hydrogen and the coolant. The fourth separator 19 is connected to the fifth cooler 18 via a pipeline and is used to separate the condensate from the product hydrogen to obtain secondary purified hydrogen.

[0081] In this application, the fifth cooler can specifically be a water cooler, and the coolant can be cooling water, which can be used to cool the pressurized product hydrogen gas, so that the uncondensed water vapor in the product hydrogen gas is condensed into condensate.

[0082] In this application, the product hydrogen is pressurized by the second pressurizer 17, and then heat-exchanged with the coolant by the fifth cooler 18 to cool down the pressurized product hydrogen. This allows the uncondensed water vapor in the product hydrogen to condense into condensate, which is then separated by the fourth separator 19, further improving the purity of the hydrogen.

[0083] In this application, a third liquid level controller 20 is provided on the fourth separator 19 to control the condensate level in the fourth separator 19. This can prevent the condensate level in the fourth separator 19 from being too high, which would affect the efficiency of hydrogen-condensate separation. In addition, it can also prevent the condensate level in the fourth separator 19 from being too low, which would prevent hydrogen leakage from the drain outlet and reduce the output, or prevent outside air from entering from the drain outlet and reducing the purity of hydrogen. Thus, it can be ensured that the purity of hydrogen during the condensate separation process is not affected by other impurities.

[0084] like Figure 3 As shown, the alkaline washing device 21 can be used to remove carbon dioxide from the secondary purified hydrogen to obtain tertiary purified hydrogen. In the alkaline washing device, carbon dioxide in the secondary purified hydrogen can be absorbed by alkaline washing liquid to achieve the purpose of purifying hydrogen. The alkaline washing liquid can specifically be methyldiethanolamine. Other types of alkaline washing liquids can also be used according to actual needs. This application does not make specific limitations on this.

[0085] like Figure 3 As shown, the drying device 22 contains a solid desiccant used to absorb residual water vapor in the three-stage purified hydrogen gas to obtain the target product, hydrogen gas. Specifically, the solid desiccant can be calcium chloride, aluminum oxide, or other desiccants depending on actual needs; this application does not impose specific limitations on this.

[0086] In this application, the drying device 22 can absorb water vapor that the first water removal subsystem D and the second water removal subsystem E failed to completely separate, and can also absorb water vapor that may be carried in the hydrogen after alkaline washing, thereby further improving the purity of the hydrogen.

[0087] Continue to combine Figure 3 The hydrogen purification system may also include a third pressure controller 23, which can be used to control the pressure of the hydrogen purification system to maintain stability, so as to ensure that the hydrogen purification system can operate stably, thereby improving the efficiency and purity of hydrogen purification, and thus improving the purity of hydrogen.

[0088] Next, in order to enable those skilled in the art to better understand the hydrogen purification method, the following will be combined with Figure 4The hydrogen purification method is described in detail.

[0089] See Figure 4 The figure shows a flowchart of a hydrogen purification method according to one embodiment of this application. As shown, the hydrogen purification method may include at least the following steps 410 to 450:

[0090] Step 410: The water-containing hydrogen gas is sequentially passed into the third cooler and the fourth cooler to exchange heat with the air and coolant respectively, thereby cooling the water-containing hydrogen gas. The cooled water-containing hydrogen gas is then passed into the third separator to separate the condensate from the water-containing hydrogen gas, thereby obtaining product hydrogen gas.

[0091] Step 420: The product hydrogen is pressurized by passing it into the second pressurizer, and then the pressurized product hydrogen is passed into the fifth cooler to exchange heat with the coolant, so that the uncondensed water vapor in the product hydrogen is condensed into condensate, thus obtaining water-containing product hydrogen.

[0092] Step 430: The hydrogen gas containing water is passed into the fourth separator to separate the condensate from the hydrogen gas containing water, thereby obtaining secondary purified hydrogen gas.

[0093] Step 440: The secondary purified hydrogen is passed into an alkaline washing device for alkaline washing to remove carbon dioxide from the secondary purified hydrogen, thereby obtaining tertiary purified hydrogen.

[0094] Step 450: The three-stage purified hydrogen is passed into a drying device to remove residual water vapor from the three-stage purified hydrogen, thereby obtaining the target product hydrogen.

[0095] In this application, the purity of the target product hydrogen is greater than the purity of the product hydrogen. Specifically, the purity of the product hydrogen can be 99%, and the purity of the target product hydrogen can be 99.9%.

[0096] In this application, by sequentially passing the water-containing hydrogen gas into the third and fourth coolers for heat exchange with air and coolant respectively, the water-containing hydrogen gas can be sufficiently cooled, thereby allowing the water vapor contained in the water-containing hydrogen gas to be fully condensed into condensate, facilitating the separation of hydrogen gas and condensate, and improving the purity of hydrogen gas.

[0097] In this application, by pressurizing the product hydrogen and then cooling the pressurized product hydrogen, the uncondensed water vapor in the product hydrogen can be condensed into condensate, and the condensate is separated by a fourth separator, thereby further improving the purity of the hydrogen.

[0098] In this application, the hydrogen produced by catalytic decomposition of water vapor using a metal cracking catalyst also contains a small amount of carbon dioxide. Therefore, the carbon dioxide in the secondary purified hydrogen can be absorbed by an alkaline washing device to achieve the purpose of purifying the hydrogen.

[0099] In this application, by setting up a drying device, water vapor that cannot be completely condensed in the three-stage purified hydrogen can be absorbed, and water vapor carried out by the hydrogen from the alkaline washing device can also be absorbed, thereby further improving the purity of the hydrogen.

[0100] In the hydrogen purification method proposed in this application, the method can also be performed according to the following steps 460 to 490:

[0101] Step 460: When the condensate level in the third separator is higher than the first preset level, control the second level controller to open the drain outlet of the third separator to discharge the condensate.

[0102] Step 470: When the condensate level in the third separator is lower than the second preset level, control the second level controller to close the drain outlet of the third separator and stop discharging condensate. The first preset level is higher than the second preset level.

[0103] Step 480: When the condensate level in the fourth separator is higher than the first preset level, control the third level controller to open the drain outlet of the fourth separator to discharge the condensate.

[0104] Step 490: When the condensate level in the fourth separator is lower than the second preset level, control the third level controller to close the drain outlet of the fourth separator and stop discharging condensate.

[0105] In this application, the condensate levels in the third and fourth separators are controlled by the second and third level controllers, respectively. This avoids excessively high condensate levels in the third and fourth separators, which would affect the efficiency of hydrogen-condensate separation. It also avoids excessively low condensate levels in the third and fourth separators, which would prevent hydrogen leakage from the drain outlet and reduce production, or prevent outside air from entering through the drain outlet and reducing hydrogen purity. This increases hydrogen production while ensuring that hydrogen purity remains unaffected.

[0106] Based on the technical solutions proposed in this application, firstly, by sequentially passing the water-containing hydrogen gas into the third and fourth coolers for heat exchange with air and coolant respectively, the water-containing hydrogen gas can be sufficiently cooled, allowing the water vapor contained in the water-containing hydrogen gas to be fully condensed into condensate, facilitating the separation of hydrogen gas and condensate, and improving the purity of hydrogen gas. Secondly, by pressurizing the product hydrogen gas and then cooling the pressurized product hydrogen gas, the uncondensed water vapor in the product hydrogen gas can be condensed into condensate, and the condensate is separated by the fourth separator, further improving the purity of hydrogen gas. Thirdly, by setting up a drying device, the water vapor that cannot be completely condensed in the three-stage purified hydrogen gas can be absorbed, as well as the water vapor carried out by the hydrogen gas from the alkaline washing device, which can further improve the purity of hydrogen gas.

[0107] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A hydrogen purification system, characterized in that, The system includes a first water removal subsystem, a second water removal subsystem, an alkaline washing device, and a drying device connected in sequence. The first water removal subsystem is used to separate condensate from water-containing hydrogen gas to obtain product hydrogen gas; The second water removal subsystem is used to separate the remaining condensate from the product hydrogen to obtain secondary purified hydrogen. The alkaline washing device is used to remove carbon dioxide from the secondary purified hydrogen to obtain tertiary purified hydrogen. The drying device is used to dry the three-stage purified hydrogen to obtain the target product hydrogen.

2. The system according to claim 1, characterized in that, The first water removal subsystem includes: The third cooler is used for heat exchange between the water-containing hydrogen gas and the air. The fourth cooler, connected to the third cooler via a pipe, is used for heat exchange between the water-containing hydrogen gas and the coolant; The third separator, connected to the fourth cooler via a pipeline, is used to separate the condensate from the water-containing hydrogen to obtain product hydrogen.

3. The system according to claim 2, characterized in that, The second water removal subsystem includes: The second pressurizer, connected to the third separator via a pipeline, is used to pressurize the product hydrogen. The fifth cooler, connected to the second pressurizer via a pipeline, is used for heat exchange between the pressurized product hydrogen and the coolant. The fourth separator, connected to the fifth cooler via a pipeline, is used to separate the condensate from the product hydrogen to obtain secondary purified hydrogen.

4. The system according to claim 3, characterized in that, The third separator and the fourth separator are respectively equipped with a second liquid level controller and a third liquid level controller, which are used to control the condensate liquid level in the third separator and the fourth separator.

5. The system according to claim 4, characterized in that, The drying device contains a solid desiccant used to absorb residual water vapor in the three-stage purified hydrogen.

6. The system according to claim 5, characterized in that, The system also includes a third pressure controller for maintaining a stable pressure in the hydrogen purification system.

7. A method for purifying hydrogen, characterized in that, The method, executed by the system as described in claim 6, includes: The water-containing hydrogen gas is sequentially passed into the third and fourth coolers, where it exchanges heat with air and coolant respectively, thereby cooling the water-containing hydrogen gas. The cooled water-containing hydrogen gas is then passed into the third separator to separate the condensate from the water-containing hydrogen gas, thus obtaining product hydrogen gas. The product hydrogen is pressurized by passing it into the second pressurizer, and then the pressurized product hydrogen is passed into the fifth cooler to exchange heat with the coolant, so that the uncondensed water vapor in the product hydrogen is condensed into condensate, thus obtaining water-containing product hydrogen. The hydrogen from the water-containing product is passed into the fourth separator to separate the condensate from the hydrogen, thereby obtaining secondary purified hydrogen. The secondary purified hydrogen is passed into an alkaline washing device for alkaline washing to remove carbon dioxide from the secondary purified hydrogen, thereby obtaining tertiary purified hydrogen. The three-stage purified hydrogen is passed into a drying device to remove residual water vapor, thereby obtaining the target product hydrogen.

8. The method according to claim 7, characterized in that, The method further includes: During the hydrogen purification process, the pressure of the hydrogen purification system is kept stable by a third pressure controller.

9. The method according to claim 7, characterized in that, The method further includes: When the condensate level in the third separator is higher than the first preset level, the second level controller opens the drain outlet of the third separator to discharge the condensate. When the condensate level in the third separator is lower than the second preset level, the second level controller closes the drain outlet of the third separator to stop discharging condensate, and the first preset level is higher than the second preset level. When the condensate level in the fourth separator is higher than the first preset level, the third level controller opens the drain outlet of the fourth separator to discharge the condensate. When the condensate level in the fourth separator is lower than the second preset level, the third level controller closes the drain outlet of the fourth separator to stop discharging condensate.

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