A pressure swing adsorption system for ease of maintenance

Abstract

This invention relates to the field of hydrogen purification and discloses a pressure swing adsorption (PSA) system that is easy to maintain. The system includes at least two adsorption tower groups, each connected to a feed pipe and a product pipe. Branch pipes connect both the feed pipe and the product pipe, with the feed inlet of the feed pipe connected to a feed main pipe and the product outlet of the product pipe connected to a product main pipe. Shut-off valves are installed on the branch pipes, the feed main pipe, and the product main pipe, and these shut-off valves are located between the two adsorption tower groups. This invention solves the problem of the inability to perform online maintenance on the programmable valves in the PSA system, which leads to a decrease in hydrogen purification yield and an increase in production costs.

Description

Technical Field

[0001] This invention relates to the field of hydrogen purification, and more specifically to a pressure swing adsorption system that is easy to maintain. Background Technology

[0002] Pressure Swing Adsorption (PSA) is a novel gas adsorption separation technology with the following advantages: high product purity; generally operates at room temperature and relatively low pressure; bed regeneration does not require heating, resulting in energy savings and cost-effectiveness; simple equipment, easy operation and maintenance; and continuous cyclic operation, allowing for full automation. Therefore, since its emergence, this new technology has attracted the attention of industries worldwide, leading to rapid development and increasing maturity through competitive research and development. Its application is particularly widespread in hydrogen purification processes.

[0003] Pressure swing adsorption (PSA) for hydrogen purification utilizes two properties of adsorbents in physical adsorption: first, the adsorption capacity for different components varies, allowing for preferential adsorption of impurities in the hydrogen source, thus purifying the hydrogen; second, the adsorption capacity of the adsorbate on the adsorbent increases with the partial pressure of the adsorbate and decreases with the adsorption temperature, enabling adsorption at low temperatures and high pressures, and desorption and regeneration at high temperatures and low pressures, thus forming an adsorption and regeneration cycle for continuous separation and purification of hydrogen. It is currently the most widely used hydrogen purification technology. Typically, PSA purification involves multiple interconnected adsorption towers filled with adsorbent. Raw hydrogen is introduced into each tower, undergoing adsorption, pressure equalization and depressurization, reverse release, vacuuming, pressure equalization and pressurization, and final pressurization to obtain the final product hydrogen. Control valves are installed on the pipelines connecting the adsorption towers to regulate gas flow, and the frequent gas flow within each tower necessitates frequent opening and closing of these valves. Frequent opening and closing of the control valves over extended periods leads to severe internal leakage, significantly impacting system stability and long-term operation. Some control valves also exhibit external leakage, posing significant safety hazards and necessitating timely maintenance. However, since all existing adsorption towers are interconnected, and gas flow is controlled by control valves on the connecting pipelines, maintenance of these valves cannot be performed while the system is running. Repairing control valves requires disassembly and removal from the site, which is impossible to do online. Therefore, when a control valve leaks, the entire system must be shut down for repair. However, shutting down the entire system for valve repair results in a complete shutdown, severely reducing hydrogen purification yield and impacting purification efficiency.

[0004] Therefore, to reduce the danger caused by leaks while preventing system shutdown, the inventors attempted to shut down the adsorption tower connected to the leaking control valve when a leak was detected. This meant the leaking control valve was closed, no longer under program control, preventing gas flow and allowing only other adsorption towers to operate, thus maintaining system operation without interruption. Repair of the leaking control valve was only necessary if the system had to be shut down for other reasons. While this method avoids immediately shutting down the entire system, it still has the following problems:

[0005] Disconnecting and stopping the adsorption tower connected to the leaking control valve will reduce the number of adsorption towers operating in the system. This means that the raw material crude hydrogen that should be purified in this adsorption tower cannot enter it and will instead enter other adsorption towers. Since the adsorption capacity of other adsorption towers is fixed, the extra raw material crude hydrogen that enters cannot be purified and can only be discharged as desorption gas. This will result in a significant decrease in hydrogen purification yield. Furthermore, since some raw material crude hydrogen is discharged without being purified, it will also increase production costs. Reducing the amount of raw material crude hydrogen fed into the adsorption towers to lower the system load will still reduce hydrogen purification efficiency. Summary of the Invention

[0006] The present invention aims to provide a pressure swing adsorption (PSA) system that is easy to maintain, which can solve the problem that the inability to perform online maintenance on the programmable valves in the PSA system leads to a decrease in hydrogen purification yield and an increase in production costs.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A pressure swing adsorption (PSA) system that is easy to maintain includes at least two adsorption tower groups. Each adsorption tower group is connected to a raw material pipe and a product pipe. Each raw material pipe and product pipe is connected to a branch pipe. The feed end of each raw material pipe is connected to a raw material collection pipe, and the discharge end of each product pipe is connected to a product collection pipe. Each branch pipe, raw material collection pipe, and product collection pipe is equipped with a shut-off valve, and the shut-off valve is located between the two adsorption tower groups.

[0009] The principle of this scheme is as follows: During the purification of crude hydrogen, the shut-off valve remains open. A programmable valve controls the opening and closing of the raw material pipe, product pipe, and branch pipes connecting them. Crude hydrogen is fed into the adsorption tower through the raw material pipe, and the product hydrogen, after pressure swing adsorption, is transported to the next process via the product pipe. Other operations of the adsorption tower are performed through several branch pipes, such as pressure equalization and depressurization, reverse release, vacuuming, flushing and vacuuming, and release of desorbed gas. When an internal leak occurs in the programmable valve after prolonged operation, all shut-off valves on the raw material pipe, product pipe, and branch pipes connecting the leaking valve in the adsorption tower group are closed. This isolates the adsorption tower group containing the leaking valve from other adsorption tower groups. The leaking valve is then repaired, while the adsorption towers in other groups continue to operate normally. After repair, all closed shut-off valves are reopened, allowing the isolated adsorption tower group to be put back into system use promptly.

[0010] The beneficial effects of this invention are as follows:

[0011] 1. The process control valve can be inspected or repaired online, meaning that the process control valve can be inspected or repaired simultaneously with hydrogen purification, ensuring the efficiency and output of hydrogen purification: The technical solution of this invention involves setting up at least two adsorption tower groups, and installing shut-off valves on the raw material pipe, product pipe, and branch pipes connecting the raw material pipe and product pipe of each adsorption tower. When the process control valve experiences internal leakage during prolonged system operation, the operator closes all shut-off valves on the raw material pipe, product pipe, and branch pipes connecting the raw material pipe and product pipe of the adsorption tower group containing the leaking process control valve, thereby shutting off the leakage. The adsorption tower group is isolated from other adsorption tower groups. At this time, the operator can repair or repair the programmable valve with internal leakage, while the adsorption towers in other adsorption tower groups can operate normally. That is, the system can purify hydrogen while repairing the programmable valve with internal leakage, and the programmable valve can be put into use immediately after repair by opening all closed shut-off valves. This allows the isolated adsorption tower group to be put into use in a timely manner, without causing the entire system to shut down or the adsorption tower connected to the programmable valve with leakage to be disconnected and stopped, thus ensuring the efficiency and output of hydrogen purification.

[0012] 2. Ensuring all programmable valves are always in a state of normal operation, reducing the number of shutdowns, and improving the product hydrogen yield: The technical solution of this invention sets up the adsorption tower as at least two adsorption tower groups, and installs shut-off valves on the raw material pipe, hydrogen pipe, and branch pipe between each pair of adsorption tower groups. When one adsorption tower is in operation, the operator can inspect the programmable valves on the other adsorption tower group that is not in operation at any time. If a programmable valve leaks, all shut-off valves on the adsorption tower group where the leaking programmable valve is located can be closed, and then maintenance can be carried out in a timely manner. This ensures that all programmable valves are in a state of normal operation, which can effectively reduce the number of shutdowns and avoid system downtime. It does not delay hydrogen purification and further ensures the safe operation of programmable valves, avoiding serious internal or external leaks, thereby ensuring the efficiency of hydrogen purification and improving the product hydrogen yield.

[0013] Furthermore, every two adsorption tower groups form an adsorption zone.

[0014] By adopting the above technical solution, the number of shut-off valves can be reduced, thus lowering costs. Shut-off valves are only required on the raw material pipe, product pipe, and branch pipes connecting the raw material pipe and product pipe between two adsorption tower groups in one adsorption zone. It is not necessary to install shut-off valves on the raw material pipe, product pipe, and branch pipes connecting the raw material pipe and product pipe between two adjacent adsorption tower groups in different adsorption zones.

[0015] Furthermore, the adsorption zone includes a left adsorption zone and a right adsorption zone; each adsorption tower group includes three adsorption towers, and each adsorption tower is electrically connected to a control system.

[0016] The adsorption zone includes a left adsorption zone and a right adsorption zone, and each adsorption tower group includes 3 adsorption towers, meaning the system includes a total of 12 adsorption towers. To solve the problem of online maintenance of the programmable valves, the inventors initially adopted a method of installing shut-off valves on the raw material and product pipes of each adsorption tower, thereby isolating the adsorption tower connected to the programmable valve that has internal leakage. However, in actual operation, the inventors found that due to the complexity of the equipment installation pipelines and the close spacing between installations, installing shut-off valves on the raw material and product pipes of each adsorption tower would require a very large number of shut-off valves. Specifically, each tower needs to install 10 shut-off valves, and 12 towers would require 120 shut-off valves. There is not enough space to install shut-off valves on the raw material and product pipes of each adsorption tower unless the entire pipeline is rearranged. However, rearranging the pipeline requires sufficient space, and the construction period for rearranging the pipeline is long. The cost of replacing and adding pipelines is too high, and the cost of installing too many shut-off valves is also too high, resulting in an overall high cost. The inventors continued their research. Since the goal was to minimize the number of valves required, they decided to divide the 12 adsorption towers into two groups of six. This significantly reduced the number of shut-off valves. However, in practice, they discovered that dividing the towers into groups of six required setting the program to run with only six towers. This necessitated adjusting the load of the pressure swing adsorption section to its minimum, which greatly increased the amount of desorbed gas. This would affect the normal operation of the next process after hydrogen purification, significantly increasing production costs.

[0017] To ensure the smooth purification of the raw crude hydrogen without affecting the normal operation of the next process after purification, i.e., to guarantee the normal operation of the system, the inventors temporarily set aside the cost issue and continued their research. They discovered that operating eight adsorption towers could meet the needs of different adsorption towers performing adsorption, pressure equalization and depressurization, reverse release, vacuuming, and pressure equalization and pressurization, ensuring a continuous output of purified hydrogen and the smooth operation of the next process without affecting its normal operation. However, with eight towers operating, the twelve adsorption towers could not be evenly grouped; they could only be divided into three groups of four. If the programmable valve on any adsorption tower leaked internally, the entire adsorption tower group containing that tower would be isolated. Although this method was feasible, the inventors continued to consider the smooth operation of the system and found that if only divided... With three groups, isolating one group could lead to an emergency where internal leakage in the control valves of the remaining eight adsorption towers could disrupt the system's normal operation. Therefore, for safety, at least one tower needs to be a backup. The inventor discovered that operating eight towers and having one as a backup results in nine towers. Separating nine towers from twelve leaves three, meaning the twelve towers can be divided into four groups. After grouping the adsorption towers, the inventor proceeded with the installation of shut-off valves. During installation, the inventor found that dividing the twelve towers into four groups not only ensured the system could smoothly purify the raw hydrogen without affecting the subsequent purification process, but also required less installation space, eliminating the need for pipeline relocation or a new installation site. Furthermore, the number of shut-off valves required was relatively small, resulting in a shorter construction period and lower costs. By electrically connecting a control system and display screen to each adsorption tower, the operating mode of each tower can be easily controlled.

[0018] Furthermore, a nitrogen purging pipe is connected to the raw material pipe; the nitrogen purging pipe includes a main nitrogen purging pipe and several nitrogen purging branch pipes connected to the main nitrogen purging pipe, and each adsorption tower group has a nitrogen purging branch pipe connected to the raw material pipe, and the nitrogen purging branch pipe is connected to the side of the shut-off valve near the adsorption tower; each nitrogen purging branch pipe is equipped with a nitrogen purging valve.

[0019] By adopting the above technical solution, nitrogen gas can be introduced into the adsorption tower through the nitrogen filling pipe to replace the gas in the adsorption tower by connecting the nitrogen filling pipe, thus preventing safety accidents during the maintenance or operation of the adsorption tower. Furthermore, by setting the nitrogen filling pipe as a main nitrogen filling pipe and a nitrogen filling branch pipe connected to the main nitrogen filling pipe, and connecting a nitrogen filling valve to the nitrogen filling branch pipe, it is easier to control the nitrogen filling of a specific adsorption tower or adsorption tower when nitrogen gas needs to be introduced into a particular adsorption tower or adsorption tower.

[0020] Furthermore, a vent pipe is connected to the vent pipeline assembly.

[0021] By adopting the above technical solution, when a certain programmable valve malfunctions and needs to be repaired, the product hydrogen gas in it can be discharged through the vent pipe, preventing safety accidents from occurring when directly repairing the adsorption tower.

[0022] Furthermore, the vent pipe includes a main vent pipe and several vent branch pipes connected to the main vent pipe, and each adsorption tower group has a vent branch pipe connected to its product pipe; each vent branch pipe is equipped with a vent valve.

[0023] By adopting the above technical solution, the vent pipe is configured as a main vent pipe and vent branch pipes connected to the main vent pipe. Each adsorption tower group's product pipe is connected to a vent branch pipe, and each vent branch pipe is equipped with a vent valve. When it is necessary to isolate a certain adsorption tower group, only the vent valve on the vent branch pipe connected to the product pipe of the adsorption tower group to be isolated can be opened, while all other vent valves are closed, thus preventing interference with the normal operation of other adsorption towers. Furthermore, by setting up a main vent pipe, regardless of which adsorption tower group's product hydrogen is discharged, it can be discharged to a fixed system or location for centralized treatment, which is more convenient, such as centralized discharge to a flare for combustion.

[0024] Furthermore, a sampling tube is connected to the venting main pipe, and a sampling valve is provided on the sampling tube.

[0025] Using the above technical solution, after the online isolation maintenance of the programmable valve is completed and before the isolated adsorption tower is put back into use, the gas in the isolated adsorption tower group can be sampled and analyzed through a sampling tube to prevent oxygen from remaining in the adsorption tower and causing the adsorbent to be poisoned and deactivated.

[0026] Furthermore, a gate valve is provided on the venting main pipe.

[0027] By adopting the above technical solution, a gate valve can be installed on the vent main pipe to provide double protection for the vent pipe. This prevents internal leakage caused by operators accidentally failing to close the vent valve tightly during system operation. In addition, after the online isolation maintenance of the programmable valve is completed, when the adsorption tower is put back into use, the vent main pipe can be further closed by the gate valve before the gas sample analysis in the vent main pipe is qualified, to prevent the flare pipeline from entering air and causing a flash explosion, thus preventing a safety accident.

[0028] Furthermore, each of the raw material pipes is equipped with a pressure gauge.

[0029] By adopting the above technical solution, a pressure gauge is installed on the raw material pipe, which can display the adsorption tower pressure on the pressure gauge when the display instrument fails, thus making it easier for operators to observe the pressure changes in the adsorption tower at any time.

[0030] Furthermore, a raw material hydrogen delivery pipe is connected to the raw material pipe, and a separatory tank is connected to the end of the raw material hydrogen delivery pipe away from the raw material pipe.

[0031] Using the above technical solution, when crude hydrogen gas is introduced into the adsorption tower, the moisture in the crude hydrogen gas can be separated by a separator. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure in Embodiment 1 of the present invention. Detailed Implementation

[0033] The following detailed description illustrates the specific implementation method:

[0034] The reference numerals in the accompanying drawings of the instruction manual include: adsorption tower 1, raw material collection pipe 2, product collection pipe 3, nitrogen charging pipe 4, nitrogen charging main pipe 401, nitrogen charging secondary pipe 402, vent pipe 5, vent main pipe 501, vent secondary pipe 502, branch pipe 6, branch main pipe 601, branch secondary pipe 602, separator 7, storage device 8, nitrogen supply device 9, programmable valve 10, shut-off valve 11, vent valve 12, pressure gauge 13, gate valve 14, sampling pipe 15, sampling valve 16, nitrogen charging valve 17, raw material hydrogen delivery pipe 18, raw material hydrogen delivery main pipe 1801, raw material hydrogen delivery secondary pipe 1802, raw material pipe 19, and product pipe 20.

[0035] Example 1

[0036] like Figure 1 As shown, a pressure swing adsorption (PSA) system that is easy to maintain includes 12 adsorption towers 1, all of which are electrically connected to the same control system. In this embodiment, the control system is specifically a DCS control system. The 12 adsorption towers 1 are evenly divided into 4 adsorption tower groups, as follows: Figure 1 As shown, towers A, B, and C form the first adsorption tower group; towers D, E, and F form the second adsorption tower group; towers G, H, and I form the third adsorption tower group; and towers J, K, and L form the fourth adsorption tower group. The first and second adsorption tower groups form the left adsorption zone, and the third and fourth adsorption tower groups form the right adsorption zone. Each adsorption tower 1 is connected to a raw material pipe 19 and a product pipe 20. Raw material crude hydrogen is fed into adsorption tower 1 through the raw material pipe 19, and the product hydrogen, after pressure swing adsorption, is transported to the next process through the product pipe 20. A raw material collection pipe 2 and a product collection pipe 3 are respectively provided in the left and right adsorption zones. The feed end of the raw material pipe 19 is connected to the raw material collection pipe 2, and the discharge end of the product pipe 20 is connected to the product collection pipe 3. The raw material collection pipe 2 and the product collection pipe 3 are connected as follows: Figure 1Two shut-off valves 11 are provided between towers C and D, and between towers I and J. A nitrogen purging pipe 4 is also connected to the raw material collection pipe 2. The nitrogen purging pipe 4 includes a main nitrogen purging pipe 401 and several auxiliary nitrogen purging pipes 402 connected to the main nitrogen purging pipe 401; in this embodiment, there are specifically four auxiliary nitrogen purging pipes 402. The end of the main nitrogen purging pipe 401 furthest from the auxiliary nitrogen purging pipes 402 is connected to the nitrogen supply device 9. The ends of the four auxiliary nitrogen purging pipes 402 furthest from the main nitrogen purging pipe 401 are respectively connected to the raw material collection pipe 2. Each auxiliary nitrogen purging pipe 402 is equipped with a nitrogen purging valve 17, and each adsorption tower group is connected to one auxiliary nitrogen purging pipe 402. 2; Specifically, the nitrogen purging auxiliary pipe 402 on the first adsorption tower group is connected between the left shut-off valve 11 on the raw material collection pipe 2 and tower C; the nitrogen purging auxiliary pipe 402 on the second adsorption tower group is connected between the right shut-off valve 11 on the raw material collection pipe 2 and tower D; the nitrogen purging auxiliary pipe 402 on the third adsorption tower group is connected between the left shut-off valve 11 on the raw material collection pipe 2 and tower I; and the nitrogen purging auxiliary pipe 402 on the fourth adsorption tower group is connected between the right shut-off valve 11 on the raw material collection pipe 2 and tower J. Each raw material pipe 19 is equipped with a programmable valve 10, and a pressure gauge 13 is also installed on the raw material pipe 19 between the programmable valve 10 and the adsorption tower 1. A raw material hydrogen delivery pipe 18 is also connected to the raw material collection pipe 2. The raw material hydrogen delivery pipe 18 includes a main raw material hydrogen delivery pipe 1801 and two auxiliary raw material hydrogen delivery pipes 1802 connected to the main raw material hydrogen delivery pipe 1801. Valves are installed on the auxiliary raw material hydrogen delivery pipes 1802, and the end of the auxiliary raw material hydrogen delivery pipe 1802 away from the main raw material hydrogen delivery pipe 1801 is connected to the raw material collection pipe 2. Specifically, the first auxiliary raw material hydrogen delivery pipe 1802 from left to right is connected between two shut-off valves 11 on the raw material pipes 19 of the first and second adsorption tower groups, and the second auxiliary raw material hydrogen delivery pipe 1802 is connected between two shut-off valves 11 on the raw material pipes 19 of the third and fourth adsorption tower groups. A separating tank 7 is connected to the end of the main raw material hydrogen delivery pipe 1801 away from the auxiliary raw material hydrogen delivery pipes 1802, and the separating tank 7 is connected to the raw material crude hydrogen storage device 8.

[0037] The ends of the product pipes 20 furthest from the product collection pipe 3 are all connected to the adsorption tower 1, and each product pipe 20 is equipped with a programmable valve 10. A vent pipe 5 is also connected to the product collection pipe 3. The vent pipe 5 includes a main vent pipe 501 and several auxiliary vent pipes 502 connected to the main vent pipe 501. In this embodiment, there are specifically four auxiliary vent pipes 502. Each auxiliary vent pipe 502 is equipped with a vent valve 12; and the ends of the four auxiliary vent pipes 502 furthest from the main vent pipe 501 are respectively connected to the product collection pipe 3. Specifically, as shown... Figure 1As shown, from left to right, the first vent pipe 502 is connected to the left end of the product collection pipe 3 in the left adsorption zone; the second vent pipe 502 is connected to the right end of the product collection pipe 3 in the left adsorption zone; the third vent pipe 502 is connected to the left end of the product collection pipe 3 in the right adsorption zone; and the fourth vent pipe 502 is connected to the right end of the product collection pipe 3 in the right adsorption zone. A gate valve 14 is installed at the end of the main vent pipe 501 closest to the fourth adsorption tower group. A sampling pipe 15 is connected to the left side of the gate valve 14 on the main vent pipe 501, and a sampling valve 16 is installed on the sampling pipe 15.

[0038] Both the raw material pipe 19 and the product pipe 20 are connected to several branch pipes 6. In this embodiment, five branch pipes are connected to the raw material pipe 19 and two branch pipes are connected to the product pipe 20. Other operations of the adsorption tower 1 are performed through the branch pipes 6, such as pressure equalization and depressurization, reverse discharge, vacuuming, flushing and vacuuming, and discharge of desorbed gas (this is prior art and will not be described in detail here). The branch pipe 6 includes a main branch pipe 601 and a secondary branch pipe 602 connected to the main branch pipe 601. The main branch pipe 601 connected to different adsorption towers 1 for the same operation is integrally formed. The end of the secondary branch pipe 602 away from the main branch pipe 601 is connected to the product pipe 20 or the raw material pipe 19, and each secondary branch pipe 602 is equipped with a programmable valve 10; and each main branch pipe 601 has a branch valve 602 connected to the product pipe 20 or the raw material pipe 19. Figure 1 Two shut-off valves 11 are provided between towers C and D, and between towers I and J. The branch main pipe 601 is also connected to a pipe (not shown in the figure) that connects to the next process or other equipment. Specifically, the branch pipe 6 in the left adsorption zone that connects to the next process or other equipment is connected between the two shut-off valves 11 between towers C and D. The branch pipe 6 in the right adsorption zone that connects to the next process or other equipment is connected between the two shut-off valves 11 between towers I and J. The end of the pipe connecting to the next process or other equipment that is furthest from the branch pipe 6 is connected to the same pipe, which connects to the next process or other equipment.

[0039] When maintenance is required on any of the programmable valves 10 within a group, the shut-off valves 11 on the corresponding branch main pipe 601, product pipe 20, and raw material pipe 19 are closed, thereby isolating the corresponding adsorption tower group from other adsorption tower groups. For example, if maintenance is required on the programmable valve 10 in the first group, all shut-off valves 11 on the branch main pipe 601, product pipe 20, and raw material pipe 19 on the right side of tower C are closed, thus isolating the first adsorption tower group from other adsorption tower groups. While the programmable valve 10 in the first group is being maintained, the other adsorption tower groups continue to operate normally. The specific implementation process is as follows:

[0040] When the programmable valve 10 experiences internal or external leakage after prolonged system operation, if adsorption tower 1 is operating in the adsorption tower group (hereinafter referred to as the leaking adsorption tower group) where the programmable valve 10 is located, the operator should first adjust the operating mode of adsorption tower 1 through the control system, so that all adsorption towers 1 in the leaking adsorption tower group stop operating, while the other three adsorption tower groups operate normally. Then, the operator should close all the shut-off valves 11 on the raw material pipe 19, product pipe 20, and all branch main pipes 601 of the leaking adsorption tower group, isolating it from the other three adsorption tower groups. Next, open the vent valve 12 on the vent branch pipe 502 connected to the product pipe 20 and the gate valve 14 on the vent main pipe 501 in the leak adsorption tower group (the vent valves 12 on the vent branch pipes 502 connected to the product pipe 20 in other adsorption tower groups are all closed) to depressurize the leak adsorption tower group that needs maintenance; after depressurization is completed, open the nitrogen charging valve 17 on the nitrogen charging branch pipe 402 connected to the raw material pipe 19 in the leak adsorption tower group (the nitrogen charging valves 17 on the nitrogen charging branch pipes 402 connected to the raw material pipe 19 in other adsorption tower groups are all closed). (Close) Close the sampling valve 16 connected to the sampling pipe 15, and purge the isolated adsorption tower group with nitrogen to replace the product hydrogen remaining in the adsorption tower 1 and pipelines to prevent safety accidents during maintenance. The nitrogen introduced into the adsorption tower group passes through the raw material pipe 19, adsorption tower 1, product pipe 20 and branch pipe 6, and finally exits from the vent main pipe 501. After the replacement is completed, close the nitrogen charging valve 17 and depressurize the adsorption tower group with nitrogen again. After the depressurization is completed, the maintenance of the programmable valve 10 with internal or external leakage can begin. After the isolation maintenance is completed, before putting the isolated adsorption tower group back into use, open the nitrogen charging valve 17 on the nitrogen charging auxiliary pipe 402 connected to the raw material pipe 19, the vent valve 12 on the vent auxiliary pipe 502 connected to the product pipe 20, and the sampling valve 16 on the sampling pipe 15 of the adsorption tower group under maintenance. Close the gate valve 14 on the vent main pipe 501 and introduce nitrogen into the isolated adsorption tower group to replace the oxygen in the isolated adsorption tower group, preventing oxygen from entering the isolated adsorption tower group during maintenance and causing accidents such as adsorbent poisoning if it is put into use directly. At this time, the nitrogen introduced into the adsorption tower group passes through the raw material pipe 19, adsorption tower 1, product pipe 20 and branch pipe 6, and finally exits from the sampling pipe 15 through the vent main pipe 501. When exiting, the gas is sampled and analyzed through the sampling valve 16. When the sampling analysis result shows that the oxygen content is less than 0.5%, close the sampling valve 16 and the vent valve 12, and then put the isolated adsorption tower group back into the system for use.

[0041] Comparative Example 1

[0042] The difference between the comparative example and Example 1 is that the shut-off valve 11, vent pipe 5, sampling pipe 15, vent valve 12, and sampling valve 16 were not installed in the comparative example. The difference in hydrogen yield between the comparative example and Example 1 is shown in Table 1 below.

[0043] Table 1: Differences in hydrogen yield between Comparative Example 1 and Example 1

[0044]

[0045]

[0046] Experimental results show that, in this first embodiment, online maintenance of the programmable valve can effectively reduce the number of shutdowns, avoid system downtime and production stoppages, and not only ensure the purification of raw material crude hydrogen but also further guarantee the safe operation of the programmable valve, avoiding serious internal or external leaks, thereby ensuring the efficiency of hydrogen purification and improving the product hydrogen yield.

[0047] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A pressure swing adsorption system that facilitates maintenance, characterized by: The system includes at least two adsorption tower groups, each group comprising three adsorption towers, and each tower is electrically connected to a control system. Each adsorption tower group is connected to a raw material pipe and a product pipe, both of which are connected to branch pipes. The inlet of the raw material pipe is connected to a raw material collection pipe, and the outlet of the product pipe is connected to a product collection pipe. Each branch pipe, raw material collection pipe, and product collection pipe is equipped with a shut-off valve, located between the two adsorption tower groups. Each pair of adsorption towers forms an adsorption zone; the adsorption zone includes a left adsorption zone and a right adsorption zone.

2. A pressure swing adsorption system for easy maintenance according to claim 1, characterized in that: The raw material pipe is connected to a nitrogen purging pipe; the nitrogen purging pipe includes a main nitrogen purging pipe and several nitrogen purging branch pipes connected to the main nitrogen purging pipe. Each adsorption tower group has a nitrogen purging branch pipe connected to its raw material pipe, and the nitrogen purging branch pipe is connected to the side of the shut-off valve near the adsorption tower; each nitrogen purging branch pipe is equipped with a nitrogen purging valve.

3. A pressure swing adsorption system for easy maintenance according to claim 2, characterized in that: The product tube is connected to a vent pipe.

4. A pressure swing adsorption system for easy maintenance according to claim 3, characterized in that: The vent pipe includes a main vent pipe and several vent branch pipes connected to the main vent pipe, and each adsorption tower group has a vent branch pipe connected to its product pipe; each vent branch pipe is equipped with a vent valve.

5. A pressure swing adsorption system for ease of maintenance according to claim 4 wherein: A sampling tube is connected to the venting main pipe, and a sampling valve is provided on the sampling tube.

6. A pressure swing adsorption system for easy maintenance according to claim 5, characterized in that: The venting main pipe is equipped with a gate valve.

7. A pressure swing adsorption system convenient for maintenance according to claim 6, characterized in that: Pressure gauges are installed on all the raw material pipes.

8. A pressure swing adsorption system for easy maintenance according to claim 7, characterized in that: The raw material pipe is connected to a raw material hydrogen delivery pipe, and the end of the raw material hydrogen delivery pipe away from the raw material pipe is connected to a separatory tank.

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