A method for deep purification of hydrogen with wide load and high recovery rate

Abstract

The application discloses a hydrogen deep purification method with wide load and high recovery rate, which comprises the following steps: crude hydrogen containing oxygen, water and carbon dioxide is introduced into a deoxidation reactor filled with a catalyst to perform a catalytic deoxidation reaction, so that oxygen reacts with hydrogen to generate water, and high-temperature wet hydrogen is obtained; wherein the deoxidation reactor is filled with at least a low-temperature activation catalyst and a medium-high-temperature main catalyst; the high-temperature wet hydrogen is cooled, and liquid water generated by condensation is separated, so that saturated micro-wet hydrogen rich in carbon dioxide is obtained; and the saturated micro-wet hydrogen is introduced into an adsorption system to perform deep dehydration and decarburization on the saturated micro-wet hydrogen, so that high-purity product hydrogen is obtained. The embodiment of the application can maintain stable high-purification effect in a wide load range, and meets application requirements.

Description

Technical Field

[0001] This invention relates to the field of hydrogen purification technology, and more specifically to a method for deep purification of hydrogen with a wide load and high recovery rate. Background Technology

[0002] Hydrogen energy, as a clean and efficient secondary energy source, is increasingly widely used in fuel cell vehicles, distributed power generation, and industrial hydrogen refueling. Scenarios such as hydrogen for fuel cells, hydrogen production via water electrolysis followed by purification, and direct hydrogen extraction from coal gas have extremely stringent requirements for hydrogen purity, necessitating the control of impurities such as oxygen, water, and carbon dioxide at extremely low levels.

[0003] Existing technologies for purifying crude hydrogen include cryogenic distillation, pressure swing adsorption (PSA), and membrane separation. However, these technologies generally suffer from several drawbacks: some methods (such as cryogenic distillation) have excessively high energy consumption and operating costs; others (such as traditional PSA) are poorly adaptable to load fluctuations, making it difficult to maintain high purification efficiency under conditions of large fluctuations in crude hydrogen production. They also suffer from incomplete deoxygenation, resulting in low overall recovery rates, failure to fully utilize crude hydrogen feedstock, and difficulty in consistently producing high-purity hydrogen. Especially in actual industrial production, crude hydrogen production often fluctuates due to upstream hydrogen production processes, making it difficult for existing purification technologies to maintain stable high purification levels over a wide load range. Summary of the Invention

[0004] This invention provides a method for deep purification of hydrogen with a wide load and high recovery rate, aiming to overcome the above-mentioned technical difficulties.

[0005] To address the aforementioned problems, this invention discloses a method for deep purification of hydrogen with a wide operating load and high recovery rate, comprising the following steps: Crude hydrogen containing oxygen, water, and carbon dioxide is passed into a deoxygenation reactor filled with a catalyst to carry out a catalytic deoxygenation reaction, in which oxygen and hydrogen react to produce water, resulting in high-temperature wet hydrogen; wherein the deoxygenation reactor is filled with at least a low-temperature activating catalyst and a medium-to-high-temperature main catalyst. The high-temperature humid hydrogen gas is cooled and the liquid water produced by condensation is separated to obtain saturated slightly humid hydrogen gas rich in carbon dioxide. Saturated slightly moist hydrogen gas is introduced into the adsorption system to perform deep dehydration and decarbonization of the saturated slightly moist hydrogen gas, thereby obtaining high-purity product hydrogen gas.

[0006] In one embodiment of the present invention, the adsorption system includes at least two adsorption towers connected in parallel, and each adsorption tower is filled with a desiccant and a carbon dioxide adsorbent from bottom to top between its inlet and outlet. The steps of introducing saturated slightly moist hydrogen gas into an adsorption system to perform deep dehydration and decarbonization of the saturated slightly moist hydrogen gas to obtain high-purity product hydrogen gas include: Saturated slightly moist hydrogen gas is passed into each adsorption tower. The adsorption tower is used to perform deep dehydration and decarbonization of the saturated slightly moist hydrogen gas to obtain high-purity product hydrogen gas.

[0007] In one embodiment of the present invention, the method further includes: Monitor the water content and / or carbon dioxide content of the high-purity hydrogen product flowing out of the outlet of each adsorption tower; When the water content of the high-purity product hydrogen flowing out of a certain adsorption tower reaches the preset saturation threshold and / or the carbon dioxide concentration change rate exceeds the preset change rate threshold, the outlet of the adsorption tower is purged with regenerated gas so that waste gas rich in water vapor and carbon dioxide flows out from the inlet of the adsorption tower and is merged into crude hydrogen. The regenerated gas is a portion of the high-purity hydrogen product obtained.

[0008] In one embodiment of the present invention, the method further includes: Record the historical operating data of each adsorption tower, including the adsorption cycle duration, regeneration gas consumption, and purity change data of the high-purity product hydrogen flowing out. Based on historical operating data, the remaining effective adsorption capacity of the desiccant and / or carbon dioxide adsorbent in the adsorption tower is predicted by a pre-trained machine learning model. A maintenance warning signal is generated when the predicted remaining effective adsorption capacity of the desiccant and / or carbon dioxide adsorbent in the adsorption tower is lower than the corresponding preset capacity threshold.

[0009] In one embodiment of the present invention, the adsorption system further includes a pressure balancing pipeline and an airflow buffer tank, wherein the pressure balancing pipeline is disposed between any two adsorption towers, and the pressure balancing pipeline and the airflow buffer tank are connected; the method further includes: The pressure of each of the two adsorption towers connected by the pressure balancing pipeline is monitored; When the pressure difference between the two adsorption towers is greater than or equal to the preset pressure difference threshold, the control pressure balance pipeline is opened. When the pressure difference between the two adsorption towers is less than the preset pressure difference threshold, the control pressure balance pipeline is shut off.

[0010] In one embodiment of the present invention, the activation temperature of the low-temperature activating catalyst is ≤40°C, and the operating temperature of the high-temperature main catalyst is 60~120°C.

[0011] In one embodiment of the present invention, the loading amount of the high-temperature main catalyst is greater than that of the low-temperature activating catalyst; the low-temperature activating catalyst and the high-temperature main catalyst are sequentially filled at the inlet and outlet of the self-deoxygenation reactor.

[0012] In one embodiment of the present invention, the step of cooling high-temperature humid hydrogen gas and separating the liquid water produced by condensation to obtain saturated slightly humid hydrogen gas rich in carbon dioxide includes: The crude hydrogen gas is preheated using high-temperature humid hydrogen gas to achieve the first cooling of the high-temperature humid hydrogen gas. The high-temperature, humid hydrogen gas, after the first cooling, is cooled a second time through a water-cooling system to separate the liquid water produced by condensation, thus obtaining saturated, slightly humid hydrogen gas rich in carbon dioxide.

[0013] In one embodiment of the present invention, the step of subjecting the high-temperature wet hydrogen gas after the first cooling to a second cooling through a water cooling system to separate the liquid water produced by condensation and obtain saturated slightly wet hydrogen gas rich in carbon dioxide includes: The hot, wet hydrogen gas, after the first cooling, is cooled a second time through a water cooling system, and the temperature of the hot, wet hydrogen gas is monitored during the second cooling process. Based on the temperature of the high-temperature humid hydrogen gas obtained from monitoring, the cooling water parameters in the water cooling system are controlled until the high-temperature humid hydrogen gas is cooled to the target temperature T, so as to separate the liquid water generated by condensation and obtain saturated slightly humid hydrogen gas rich in carbon dioxide. Where T1+ΔT≤T≤15℃; where T1 is the dew point temperature of saturated slightly moist hydrogen gas containing both carbon dioxide and water under the current operating pressure, and ΔT is the safety margin temperature.

[0014] In one embodiment of the present invention, the method further includes: Real-time monitoring of oxygen concentration in crude hydrogen and gas flow rate entering the deoxygenation reactor; The residence time of crude hydrogen in the deoxygenation reactor is controlled based on the monitored oxygen concentration and gas flow rate.

[0015] The embodiments of the present invention have the following advantages: This invention achieves highly efficient catalytic deoxygenation over a wide load range by combining a low-temperature activating catalyst and a medium-to-high-temperature main catalyst in the deoxygenation reactor. The low-temperature activating catalyst can rapidly activate the reaction at the initial stage of process start-up or under low load conditions, while the medium-to-high-temperature main catalyst ensures the thoroughness of the deoxygenation reaction during the stable operation stage, which can fully convert the oxygen in the crude hydrogen into water and avoid the adverse effects of residual oxygen on the subsequent adsorption system and the quality of the product hydrogen.

[0016] This invention removes different impurities in stages: first, oxygen is removed; then most of the water is removed; and finally, water and carbon dioxide are deeply removed. This avoids the problem of mutual interference between impurities such as oxygen, water, and carbon dioxide in a single purification process, and ultimately produces high-purity hydrogen. It maintains a stable high purification effect over a wide load range, meeting application requirements. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a method for deep purification of hydrogen with a wide load and high recovery rate according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the control method for a deoxygenation reactor according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the regeneration operation method of the adsorption tower according to an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the generation of maintenance early warning signals for adsorption towers according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the pressure balancing method for an adsorption tower according to an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] refer to Figure 1 This invention provides a method for deep purification of hydrogen with a wide load and high recovery rate, which may include the following steps: Step S101: Crude hydrogen containing oxygen, water, and carbon dioxide is introduced into a deoxygenation reactor filled with a catalyst to carry out a catalytic deoxygenation reaction, so that oxygen reacts with hydrogen to produce water and high-temperature wet hydrogen is obtained; wherein, the deoxygenation reactor is filled with at least a low-temperature activating catalyst and a medium-high temperature main catalyst. Step S102: Cool the high-temperature wet hydrogen gas and separate the liquid water produced by condensation to obtain saturated slightly wet hydrogen gas rich in carbon dioxide. Step S103: Saturated slightly moist hydrogen gas is introduced into the adsorption system to perform deep dehydration and decarbonization of the saturated slightly moist hydrogen gas to obtain high-purity product hydrogen gas.

[0021] As shown in step S101, the crude hydrogen gas of the present invention first undergoes a catalytic deoxygenation reaction. In the deoxygenation reactor, a very small amount of hydrogen gas acts as a reducing agent, causing oxygen to react and generate water under the action of a catalyst. Compared with the prior art, the deoxygenation reactor of this embodiment is at least filled with a low-temperature activating catalyst and a medium-to-high-temperature main catalyst. Optionally, the activation temperature of the low-temperature activating catalyst is ≤40℃, and the operating temperature of the high-temperature main catalyst is 60~120℃. The activation temperature refers to the lowest temperature at which the catalyst begins to have significant catalytic activity. The operating temperature refers to the temperature range in which the catalyst achieves the best catalytic effect during stable operation. Specifically, the low-temperature activating catalyst can be selected as Pt / Al2O3 type, with an activation temperature of about 30℃, and the high-temperature main catalyst can be selected as Pd / C type, with an operating temperature of about 80℃.

[0022] The crude hydrogen load typically varies from 5% to 110% of the rated load. Load refers to the flow rate of crude hydrogen entering the deoxygenation reactor per unit time; a higher load results in a larger feed flow rate, and a lower load results in a smaller feed flow rate. Catalytic deoxygenation is an exothermic reaction, with the heat released directly correlated with the amount of oxygen involved, which in turn is directly correlated with the crude hydrogen feed flow rate (load). When the crude hydrogen load is low or in the initial stage of the reaction (when the temperature is low), the low-temperature activating catalyst starts first, catalyzing the reaction between oxygen and hydrogen to produce water, achieving initial deoxygenation. As the reaction proceeds, the exothermic reaction raises the temperature inside the deoxygenation reactor to, for example, 60-120°C. At this point, the medium-high temperature main catalyst starts, further catalyzing the reaction between the remaining oxygen and hydrogen to ensure complete oxygen removal, ultimately yielding high-temperature wet hydrogen containing water and carbon dioxide. This embodiment of the invention, through the combined use of a low-temperature activating catalyst and a medium-high temperature main catalyst, can adapt to a wide range of crude hydrogen load variations. Under low-load conditions, the low-temperature activation catalyst first completes the initial deoxygenation, while under high-load conditions, the medium- and high-temperature main catalyst achieves deep deoxygenation. The combination of the two can stably reduce the residual oxygen in crude hydrogen to below 0.1 ppm, which is far superior to existing single catalysts. This not only solves the problem of incomplete deoxygenation of existing single catalysts over a wide load range, but also avoids the oxidative damage of residual oxygen to the adsorbent in the subsequent adsorption system.

[0023] Based on the deoxygenation requirements under wide load conditions, low-load conditions (e.g., 5%-30% of rated load) account for a relatively small proportion of the entire operating cycle, and only a small amount of low-temperature activating catalyst is needed to complete the initial deoxygenation under these conditions. High-load conditions (e.g., 30%-110% of rated load) are the mainstream operating conditions, requiring a large amount of high-temperature main catalyst to cope with the high oxygen content and high flow rate deoxygenation requirements. Therefore, in some embodiments of the present invention, the loading amount of high-temperature main catalyst is greater than that of low-temperature activating catalyst, wherein the low-temperature activating catalyst and the high-temperature main catalyst are filled sequentially from the inlet and outlet of the deoxygenation reactor. Optionally, the inlet and outlet of the deoxygenation reactor are arranged from bottom to top, and the low-temperature activating catalyst and the high-temperature main catalyst are filled from bottom to top. Further optionally, the ratio of the effective loading volume of the low-temperature activating catalyst to the high-temperature main catalyst in the deoxygenation reactor is 1:3.

[0024] To ensure complete deoxygenation under a wide load variation range of crude hydrogen, in some embodiments of the present invention, reference is made to... Figure 2 It may also include the following steps: Step S201: Real-time monitoring of oxygen concentration in crude hydrogen and gas flow rate entering the deoxygenation reactor; Step S202: Based on the monitored oxygen concentration and gas flow rate, control the residence time of crude hydrogen in the deoxygenation reactor.

[0025] Specifically, the oxygen concentration in the crude hydrogen gas can be monitored in real time using an online oxygen analyzer, and the flow rate of the crude hydrogen gas entering the deoxygenation reactor can be monitored in real time using a flow sensor. Then, based on the stoichiometry of the deoxygenation reaction and the catalytic activity of the catalyst, the minimum residence time required to ensure complete oxygen removal is determined. Based on the monitored oxygen concentration and flow rate data, the required residence time under the current operating conditions is calculated: when the oxygen concentration increases or the flow rate increases, the required minimum residence time increases; when the oxygen concentration decreases or the flow rate decreases, the required minimum residence time decreases.

[0026] Regarding the control of residence time, it can be achieved by adjusting the flow control valves at the inlet or outlet of the deoxygenation reactor, thereby controlling the residence time of crude hydrogen in the deoxygenation reactor and ensuring that the residence time is not less than the minimum residence time under the current operating conditions. For example, when the oxygen concentration in the crude hydrogen is detected to increase from 2% to 4%, the residence time can be extended from 1s to 2s by reducing the feed flow rate to ensure complete oxygen reaction.

[0027] Regardless of fluctuations in the oxygen concentration or flow rate of the crude hydrogen, this embodiment of the invention ensures sufficient contact time between the hydrogen and the catalyst by dynamically adjusting the residence time, allowing the oxygen to react completely and avoiding poor deoxygenation due to increased oxygen concentration or flow rate. This control method can adapt to fluctuations in impurity concentrations of crude hydrogen from different sources (e.g., the oxygen concentration of industrial by-product hydrogen may vary with the production process), eliminating the need for manual adjustment of process parameters and improving the system's automation level and operational flexibility.

[0028] As shown in step S102, the high-temperature wet hydrogen gas can then be cooled to condense water vapor into liquid water. The resulting liquid water is then separated to obtain saturated slightly wet hydrogen gas rich in carbon dioxide. Understandably, the saturated slightly wet hydrogen gas has a significantly reduced water content compared to the high-temperature wet hydrogen gas. This process greatly reduces the dehydration load on the subsequent adsorption system, allowing the adsorbent to focus on removing carbon dioxide and improving the adsorption efficiency of the system.

[0029] In some embodiments of the present invention, step S102 can be implemented by the following steps: Sub-step S102-1 involves preheating the crude hydrogen gas with high-temperature humid hydrogen gas to achieve the first cooling of the high-temperature humid hydrogen gas. In sub-step S102-2, the high-temperature wet hydrogen gas after the first cooling is cooled a second time through a water cooling system to separate the liquid water produced by condensation and obtain saturated slightly wet hydrogen gas rich in carbon dioxide.

[0030] This invention embodiment involves two cooling operations on the high-temperature humid hydrogen gas. The first cooling operation preheats the crude hydrogen gas with the high-temperature humid hydrogen gas, transferring its heat to the crude hydrogen gas and thus lowering its temperature. Specifically, the high-temperature humid hydrogen gas obtained in step S101 is introduced into the hot side of a heat exchanger, while the crude hydrogen gas is introduced into the cold side, achieving heat exchange between the high-temperature humid hydrogen gas and the low-temperature crude hydrogen gas, thereby reducing the temperature of the high-temperature humid hydrogen gas. Through this first cooling operation, this invention embodiment not only achieves the recovery and utilization of waste heat from the deoxygenation reaction but also increases the temperature of the crude hydrogen gas entering the deoxygenation reactor, accelerating the activation rate of the low-temperature activated catalyst and improving the deoxygenation reaction efficiency under low-load conditions. Simultaneously, the reduced temperature of the high-temperature humid hydrogen gas decreases the cooling load on the subsequent water cooling system, lowering the energy consumption of the cooling water circulation pump and avoiding the problems of high energy consumption or insufficient cooling associated with a single cooling method. The second cooling operation involves introducing the high-temperature, humid hydrogen gas, which has undergone the first cooling, into the water cooling system. Through the cooling effect of the 3-12°C cooling water, its temperature is further reduced to the water cooling temperature. At this point, the water vapor in the hydrogen gas reaches saturation and condenses into liquid water, which is then separated and discharged through a gas-liquid separation device, resulting in saturated humid hydrogen gas rich in carbon dioxide.

[0031] Furthermore, regarding the implementation process of sub-step S102-2, the embodiments of the present invention can also be implemented through the following steps: Sub-step S102-2-1 involves cooling the high-temperature wet hydrogen gas, which has undergone the first cooling process, a second cooling process using a water cooling system, and monitoring the temperature of the high-temperature wet hydrogen gas during the second cooling process. Sub-step S102-2-2: Based on the monitored temperature of the high-temperature humid hydrogen, control the cooling water parameters in the water cooling system until the high-temperature humid hydrogen is cooled to the target temperature T, so as to separate the liquid water generated by condensation and obtain saturated slightly humid hydrogen rich in carbon dioxide; where T1+ΔT≤T≤15℃; where T1 is the dew point temperature of carbon dioxide and water coexisting in the saturated slightly humid hydrogen under the current operating pressure, and ΔT is the safety margin temperature.

[0032] In this embodiment of the invention, a temperature sensor is installed at the gas outlet of the water-cooling system to monitor the temperature of the cooled gas in real time. The gas temperature signal is then transmitted to the control system. The control system automatically adjusts the cooling water flow rate of the water-cooling system based on the deviation between the monitored gas temperature and the target temperature. This stabilizes the gas temperature within the target range, significantly improving the water vapor condensation rate and facilitating the stability of the moisture load in the subsequent adsorption system. The target temperature T is set between 15°C and the dew point temperature (T1) of carbon dioxide and water coexisting at the current operating pressure, plus a safety margin temperature ΔT. This ensures that the gas is cooled to near the dew point temperature for sufficient water vapor condensation while avoiding increased cooling water energy consumption due to excessively low temperatures.

[0033] For example, in the specific implementation of this embodiment of the invention, the dew point temperature T1 of carbon dioxide and water coexisting can be calculated (e.g., T1 = 5℃) based on the current operating pressure using thermodynamic formulas or by looking up tables; a safety margin temperature ΔT = 3℃ is set (to avoid insufficient condensation due to temperature fluctuations), then the target temperature T ranges from 5 + 3 = 8℃ to 15℃, and T = 10℃ can be selected as the control target. During the adjustment of the cooling water flow rate of the water-cooling system, when the deviation between the monitored gas temperature and the target temperature is +2℃, the cooling water flow rate is increased; when the deviation is -2℃, the cooling water flow rate is decreased to ensure that the monitored temperature remains stable within the range of 10 ± 1℃.

[0034] As shown in step S103, the saturated wet hydrogen gas obtained in step S102 is introduced into the adsorption system. The adsorption system is filled with an adsorbent with high adsorption capacity for moisture and carbon dioxide. When the gas passes through the adsorbent bed, moisture and carbon dioxide are adsorbed by the adsorbent, and the outflowing gas is high-purity hydrogen gas with oxygen, most of the water, and carbon dioxide removed. This embodiment of the invention avoids the problem of mutual interference between impurities such as oxygen, water, and carbon dioxide in a single purification process (such as direct adsorption) by removing different impurities in steps (first removing oxygen, then removing most of the water, and finally deeply removing water and carbon dioxide). For example, in direct adsorption, oxygen will oxidize the adsorbent, and moisture will occupy adsorption sites, both of which will lead to low adsorbent utilization. Finally, high-purity hydrogen gas can be obtained to meet application requirements.

[0035] The adsorption system may include at least two adsorption towers connected in parallel. Each adsorption tower has a desiccant and a carbon dioxide adsorbent packed from bottom to top between its inlet and outlet. The desiccant is positioned close to the inlet of the adsorption tower to effectively prevent the carbon dioxide adsorbent from prematurely failing due to initial contact with moisture. Step S103, which involves introducing saturated slightly moist hydrogen into the adsorption system to perform deep dehydration and decarbonization of the saturated slightly moist hydrogen to obtain high-purity product hydrogen, may include: introducing saturated slightly moist hydrogen into each adsorption tower, whereby the adsorption towers are used to perform deep dehydration and decarbonization of the saturated slightly moist hydrogen to obtain high-purity product hydrogen.

[0036] In one embodiment of the present invention, reference is made to... Figure 3 It may also include the following steps: Step S301: Monitor the water content and / or carbon dioxide content of the high-purity product hydrogen flowing out of the outlet of each adsorption tower. Step S302: When the water content of the high-purity product hydrogen flowing out of a certain adsorption tower reaches a preset saturation threshold and / or the carbon dioxide concentration change rate exceeds a preset change rate threshold, the outlet of the adsorption tower is purged with regenerated gas so that waste gas rich in water vapor and carbon dioxide flows out from the inlet of the adsorption tower and is merged into crude hydrogen; wherein, the regenerated gas is a portion of the high-purity product hydrogen obtained in step S103.

[0037] Optionally, the adsorption system of this embodiment may include at least two adsorption towers connected in parallel. The inlet of each adsorption tower is connected to the saturated wet hydrogen output terminal of step S102 through a main pipe, and the outlet is connected to a product hydrogen storage or usage device through a main pipe. Each adsorption tower is equipped with an independent inlet valve, outlet valve, and regeneration valve. One end of the regeneration gas pipeline is connected to the product hydrogen main pipe, and the other end is connected to the outlet of each adsorption tower through the regeneration valve. One end of the waste gas return pipeline is connected to the inlet of each adsorption tower through the waste gas valve, and the other end is connected to the crude hydrogen main pipe.

[0038] In the initial stage, multiple adsorption towers are simultaneously in adsorption mode. The regeneration valve and exhaust valve of each tower are closed, while the inlet valve and outlet valve are open, ensuring continuous purification and preventing product supply interruptions during the regeneration of a single tower. Then, online monitoring devices (such as dew point meters for moisture content and infrared analyzers for carbon dioxide content) monitor the moisture and carbon dioxide content at the outlet of each adsorption tower in real time. When the moisture content of hydrogen at the outlet of a particular adsorption tower reaches a preset saturation threshold, or the rate of change in carbon dioxide concentration exceeds a preset rate of change threshold, it is determined that the adsorbent in that tower is nearing saturation or its adsorption capacity has decreased, and the regeneration process for that tower is initiated.

[0039] In the regeneration process of the adsorption tower, the regeneration valve and waste gas valve of the adsorption tower are opened. Then, a portion of the high-purity product hydrogen obtained in step S103 is introduced as regeneration gas into the outlet of the adsorption tower to be regenerated through the regeneration gas pipeline to perform reverse purging of the adsorption tower (i.e., the gas flow direction is opposite to that during adsorption). During the purging process, the regeneration gas desorbs the water vapor and carbon dioxide adsorbed by the adsorbent, forming waste gas rich in water vapor and carbon dioxide, which flows out from the inlet of the adsorption tower. The outflowing waste gas is channeled into the crude hydrogen main pipe through the waste gas return pipeline and re-enters the deoxygenation reactor to participate in the subsequent purification process, realizing the recycling of hydrogen and reducing hydrogen loss. This embodiment of the invention recycles hydrogen from the waste gas, avoiding the loss of hydrogen by direct emission with the waste gas in traditional regeneration processes, and increasing the hydrogen recovery rate from 85%-90% in the prior art to over 95%. In this embodiment of the invention, high-purity product hydrogen is used as the regeneration gas. Compared with the prior art, which uses inert gas as the regeneration gas, this avoids the problem of product hydrogen contamination caused by the introduction of inert gas and ensures product purity.

[0040] based on Figure 3 The method shown, further refer to Figure 4 The embodiments of the present invention may further include the following steps: Step S401: Record the historical operating data of each adsorption tower. The historical operating data includes the adsorption cycle duration, regeneration gas consumption, and purity change data of the high-purity product hydrogen flowing out. Step S402: Based on historical operating data, predict the remaining effective adsorption capacity of the desiccant and / or carbon dioxide adsorbent in the adsorption tower using a pre-trained machine learning model. Step S403: When the predicted remaining effective adsorption capacity of the desiccant and / or carbon dioxide adsorbent in the adsorption tower is lower than the corresponding preset capacity threshold, a maintenance warning signal is generated.

[0041] In the implementation of this invention, the historical operating data of each adsorption tower can be recorded in real time by the control system, including: the adsorption cycle duration of each adsorption process (i.e., the time from the start of adsorption to triggering regeneration), the amount of product hydrogen consumed in each regeneration process, and the purity change data of the product hydrogen during adsorption. During model training and deployment, a random forest algorithm can be selected as the machine learning model. The collected historical operating data is divided into training and testing sets. The adsorption cycle duration, regeneration gas consumption, and purity change rate are used as input features, and the experimentally measured remaining effective adsorption capacity of the adsorbent is used as the output label. The model is trained and optimized to ensure that the model prediction error is less than 5%. The trained model is then deployed to the control system. The control system inputs the current operating data of the adsorption tower (adsorption cycle duration, regeneration gas consumption, and purity change data) into the pre-trained machine learning model in real time. The model outputs the remaining effective adsorption capacity of the adsorbent (desiccant and carbon dioxide adsorbent). For example, the threshold for the remaining effective adsorption capacity of the desiccant can be preset to 50% of the initial capacity, and the threshold for the remaining effective adsorption capacity of the carbon dioxide adsorbent can be preset to 45% of the initial capacity. When the model predicts that the remaining capacity is lower than the corresponding threshold, the control system generates a maintenance warning signal to remind staff to replace the adsorbent in a timely manner. The maintenance warning signal refers to a signal generated by the system to prompt operators to perform adsorbent maintenance. It can be output through audible and visual alarms, system pop-ups, SMS messages, etc., and this invention is not limited to these methods.

[0042] As the adsorbent is used for longer periods, its adsorption capacity decreases, the adsorption cycle shortens, regeneration gas consumption increases, and the rate of decrease in product hydrogen purity accelerates. This invention, through collecting historical data to train a machine learning model, establishes a mapping relationship between data and remaining adsorption capacity, thereby enabling real-time prediction of the remaining adsorbent capacity. When the predicted value falls below a preset threshold, a maintenance warning is generated to prevent adsorbent failure before replacement, ensuring stable purification results.

[0043] based on Figure 3 Furthermore, to address the issue of large pressure fluctuations during adsorption tower switching, in some embodiments of the present invention, the adsorption system may further include a pressure balancing pipeline and a gas flow buffer tank. The pressure balancing pipeline is positioned between any two adsorption towers, and the pressure balancing pipeline and the gas flow buffer tank are connected. (See reference...) Figure 5 This may include the following steps: Step S501: Monitor the pressure of each of the two adsorption towers connected to the pressure balancing pipeline; Step S502: When the pressure difference between the two adsorption towers is greater than or equal to the preset pressure difference threshold, the pressure balance pipeline is opened. Step S503: When the pressure difference between the two adsorption towers is less than the preset pressure difference threshold, the pressure balance pipeline is shut off.

[0044] In this embodiment of the invention, a pressure balancing pipeline is installed between any two adsorption towers, and an electrically controlled valve is installed on each pressure balancing pipeline. The pressure balancing pipeline is connected to a gas flow buffer tank, the volume of which can be 1 / 5 of the volume of a single adsorption tower, to buffer gas flow fluctuations during the pressure balancing process. A pressure sensor is installed at the top of each adsorption tower to monitor the pressure inside the tower in real time. During pressure monitoring and control, the control system can collect pressure data of the two adsorption towers connected by the pressure balancing pipeline in real time and calculate the pressure difference ΔP. When the pressure difference between the two adsorption towers is greater than or equal to a preset pressure difference threshold, the electrically controlled valve of the pressure balancing pipeline is opened, and the gas in the two adsorption towers is interconnected through the pressure balancing pipeline and the gas flow buffer tank. The gas in the high-pressure tower slowly flows into the low-pressure tower, and the buffer tank absorbs the gas flow impact. When the pressure difference between the two adsorption towers is less than the preset pressure difference threshold, the electrically controlled valve is closed, completing the pressure balancing.

[0045] It is worth noting that before the adsorption tower switches from the regeneration state to the adsorption state, the pressure balancing procedure is initiated: the pressure balancing pipeline between the adsorption tower and the adsorption tower in the target operating state is connected, and after the pressure difference drops below the threshold, the regeneration valve / exhaust gas return valve is closed and the inlet valve / outlet valve is opened to complete the switch.

[0046] Through the embodiments of this invention, the pressure difference between the two towers is stably controlled below a preset threshold by controlling the on / off state of the pressure balancing pipeline, avoiding sudden pressure changes during adsorption tower switching and reducing the wear of the adsorbent caused by airflow impact. The airflow buffer tank further buffers airflow fluctuations, preventing sudden pressure changes from impacting pipelines, valves, adsorption towers, and other equipment, extending equipment lifespan, and reducing the probability of equipment failure. Rapid pressure balancing shortens the preparation time for adsorption tower switching and regeneration, improves the operating efficiency of parallel adsorption towers, and ensures the stability of continuous purification.

[0047] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0048] Furthermore, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes the element.

[0049] The technical solution provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the present invention, and the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for deep purification of hydrogen with a wide load and high recovery rate, characterized in that, The method includes the following steps: Crude hydrogen gas containing oxygen, water, and carbon dioxide is passed into a deoxygenation reactor filled with a catalyst to carry out a catalytic deoxygenation reaction, in which oxygen and hydrogen react to produce water, resulting in high-temperature wet hydrogen gas. The deoxygenation reactor is filled with a low-temperature activating catalyst and a medium-high temperature main catalyst sequentially from the inlet to the outlet along the gas flow direction. The amount of the medium-high temperature main catalyst is greater than the amount of the low-temperature activating catalyst. The crude hydrogen gas is preheated using the high-temperature humid hydrogen gas to achieve the first cooling of the high-temperature humid hydrogen gas; the high-temperature humid hydrogen gas after the first cooling is cooled a second time through a water cooling system to separate the liquid water produced by condensation and obtain saturated slightly humid hydrogen gas rich in carbon dioxide. The saturated slightly moist hydrogen gas is introduced into an adsorption system, wherein the adsorption system includes at least two adsorption towers connected in parallel, and each adsorption tower is filled with a desiccant and a carbon dioxide adsorbent from bottom to top between its inlet and outlet; the saturated slightly moist hydrogen gas is introduced into each adsorption tower, and the adsorption tower is used to perform deep dehydration and decarbonization on the saturated slightly moist hydrogen gas to obtain high-purity product hydrogen gas. Specifically, when the water content of the high-purity product hydrogen flowing out of a certain adsorption tower reaches a preset saturation threshold and / or the carbon dioxide concentration change rate exceeds a preset change rate threshold, a portion of the obtained high-purity product hydrogen is used to purge the outlet of the adsorption tower so that waste gas rich in water vapor and carbon dioxide flows out from the inlet of the adsorption tower, and the waste gas is then incorporated into the crude hydrogen.

2. The method for deep purification of hydrogen with a wide load and high recovery rate according to claim 1, characterized in that, The method further includes: Record the historical operating data of each adsorption tower, including the adsorption cycle duration, regeneration gas consumption, and purity change data of the high-purity product hydrogen flowing out. Based on the historical operating data, the remaining effective adsorption capacity of the desiccant and / or carbon dioxide adsorbent in the adsorption tower is predicted by a pre-trained machine learning model. When the predicted remaining effective adsorption capacity of the desiccant and / or carbon dioxide adsorbent in the adsorption tower is lower than the corresponding preset capacity threshold, a maintenance warning signal is generated.

3. The method for deep purification of hydrogen with a wide load and high recovery rate according to claim 1, characterized in that, The adsorption system further includes a pressure balancing pipeline and a gas flow buffer tank, wherein the pressure balancing pipeline is located between any two adsorption towers, and the pressure balancing pipeline and the gas flow buffer tank are connected; the method further includes: The pressure of each of the two adsorption towers connected by the pressure balancing pipeline is monitored; When the pressure difference between the two adsorption towers is greater than or equal to a preset pressure difference threshold, the pressure balance pipeline is controlled to be opened. When the pressure difference between the two adsorption towers is less than the preset pressure difference threshold, the pressure balance pipeline is shut off.

4. The method for deep purification of hydrogen with a wide load and high recovery rate according to claim 1, characterized in that, The activation temperature of the low-temperature activating catalyst is ≤40℃, and the operating temperature of the high-temperature main catalyst is 60~120℃.

5. The method for deep purification of hydrogen with a wide load and high recovery rate according to claim 1, characterized in that, The steps of subjecting the high-temperature, moist hydrogen gas, after the first cooling, to a second cooling process using a water-cooling system to separate the condensed liquid water and obtain saturated, slightly moist hydrogen gas rich in carbon dioxide include: The high-temperature wet hydrogen gas, after the first cooling, is cooled a second time through a water cooling system, and the temperature of the high-temperature wet hydrogen gas is monitored during the second cooling process. Based on the temperature of the high-temperature humid hydrogen gas obtained from monitoring, the cooling water parameters in the water cooling system are controlled until the high-temperature humid hydrogen gas is cooled to the target temperature T, so as to separate the liquid water generated by condensation and obtain saturated slightly humid hydrogen gas rich in carbon dioxide. Wherein, T1+ΔT≤T≤15℃; where T1 is the dew point temperature of the saturated slightly moist hydrogen gas containing both carbon dioxide and water under the current operating pressure, and ΔT is the safety margin temperature.

6. The method for deep purification of hydrogen with a wide load and high recovery rate according to claim 1, characterized in that, The method further includes: The oxygen concentration in the crude hydrogen and the gas flow rate entering the deoxygenation reactor are monitored in real time. The residence time of the crude hydrogen in the deoxygenation reactor is controlled based on the monitored oxygen concentration and gas flow rate.

Images