A hydrogen recovery system and method for a hydrogen refueling mother station

Abstract

This invention pertains to the field of hydrogen energy and discloses a hydrogen recovery system and method for a hydrogen refueling mother station. The system includes a hydrogen purification unit, a product gas and recovered gas compressor, and an integrated pipeline network connecting the feed gas, product gas, desorbed gas, and the long-tube vehicle. Through multiple recovery paths, the system can recover substandard purified hydrogen, desorbed gas, and replacement hydrogen from the long-tube vehicle to the fuel gas pipeline network, feed gas inlet, or desorbed gas system, respectively. It can also utilize high-purity hydrogen to regenerate the permeated adsorbent online. This invention achieves comprehensive recovery of vented combustible gases within the hydrogen refueling mother station, significantly improving the hydrogen recovery rate and ensuring the quality and supply stability of the product gas.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen energy and relates to hydrogen production, particularly a hydrogen recovery system and method for a hydrogen refueling mother station. Background Technology

[0002] Against the backdrop of the rapid development of the hydrogen energy industry, hydrogen refueling mother stations, as the core hubs of the hydrogen refueling network for hydrogen fuel cell vehicles, play a crucial role in ensuring the stability of hydrogen supply and reducing operating costs through the efficiency and economy of their hydrogen purification systems. Traditional hydrogen refueling mother stations generally use pressure swing adsorption (PSA) technology for hydrogen purification. This technology achieves impurity separation through periodic pressure changes, and has advantages such as room temperature operation and low investment. It can purify industrial by-product hydrogen (such as chlor-alkali tail gas and natural gas hydrogen production by-product gas) to over 99.999%, meeting the hydrogen standards for fuel cells and high-purity hydrogen standards.

[0003] The typical process flow of a hydrogen refueling mother station is as follows: Industrial by-product hydrogen from chemical enterprises is first purified by the hydrogen purification unit P101. The purified hydrogen meets the requirements for high-purity hydrogen or hydrogen quality indicators for hydrogen fuel cells. Then, it enters the hydrogen compressor for compression, compressing the hydrogen pressure to a maximum of 20MPa. The hydrogen then enters the filling area for filling the long-tube vehicle T1, and is then delivered to the hydrogen refueling station or other users. The desorbed gas generated by the hydrogen purification unit P101 is discharged to the flare or compressed by the compressor and sent to the fuel gas pipeline network.

[0004] The existing hydrogen refueling mother station model has the following problems:

[0005] 1. Fluctuations in the composition of upstream feed gas at the hydrogenation mother station can lead to substandard product gas quality, causing supply disruptions to downstream customers and resulting in shutdown losses for downstream enterprises.

[0006] 2. If substandard products are found during the filling process or start-up / shutdown process, the substandard gas will often be released into the flare, resulting in a great deal of waste.

[0007] 3. If the hydrogen in the long-tube vehicle fails the analysis and testing after filling, or if the hydrogen used to replace the hydrogen in the long-tube vehicle is released into the flare, the operating cost will increase.

[0008] 4. The hydrogen content in the fuel gas discharged from the hydrogen purification unit is often more than 70%, which is directly sent to the fuel gas pipeline network without fully and effectively utilizing the hydrogen, thus reducing the recovery rate.

[0009] 5. When the upstream raw gas components are severely out of standard or the hydrogen purification unit is overloaded and causes adsorbent breakthrough, the adsorbent needs high-purity hydrogen for regeneration. However, traditional hydrogen purification systems do not have this function and can only operate at low load until the adsorbent slowly recovers. This results in long downtime of the unit and affects downstream supply. Summary of the Invention

[0010] To address the problems existing in hydrogen purification systems at hydrogen refueling mother stations, such as fluctuations in feed gas composition leading to product defects, direct venting and waste of substandard hydrogen during start-up / shutdown / filling processes, high hydrogen content in desorbed gas without effective recovery, and prolonged downtime due to the inability to quickly regenerate adsorbent after penetration, this invention aims to provide an integrated and intelligently controllable hydrogen recovery system and method. This system will enable comprehensive recovery and efficient utilization of various substandard hydrogen and desorbed gas within the station, significantly improving hydrogen recovery rate and operational stability.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] The first aspect of the present invention is to provide a hydrogen recovery system for a hydrogen refueling mother station, including a hydrogen purification device, a product gas compressor, a recovery gas compressor, a long pipeline vehicle, and key instruments and control valves installed on the corresponding pipelines for monitoring and control;

[0013] The inlet of the hydrogen purification device is connected to the raw material gas pipeline, its product gas outlet is connected to the inlet of the product gas compressor through the product gas pipeline, and its desorption gas outlet is connected to the inlet of the recovery gas compressor through the desorption gas pipeline.

[0014] The outlet of the product gas compressor is connected to the filling main pipe, and the filling main pipe is connected to the long pipe vehicle through multiple filling branch pipes;

[0015] The outlet of the recovery gas compressor is connected to the raw material gas pipeline via a recovery gas pipeline;

[0016] One of the filling branch pipes is provided with a recovery branch, which includes a recovery hydrogen manual valve and a high-pressure hydrogen pipeline; the high-pressure hydrogen pipeline can be selectively connected to the raw material gas pipeline or the desorption gas pipeline;

[0017] The product gas pipeline is equipped with a substandard product gas recovery pipeline;

[0018] A product gas connection pipeline is also connected between the high-pressure hydrogen pipeline and the filling main pipe, and a product gas connection shut-off valve is installed on it.

[0019] The system also includes:

[0020] A product gas analyzer installed on the product gas pipeline is used to monitor the product gas composition.

[0021] The raw gas flow meter, raw gas pressure meter, and hydrogen purification inlet analyzer installed on the raw gas pipeline are used to monitor the raw gas flow rate, pressure, and composition.

[0022] The recovered gas analysis table and recovered gas flow meter installed on the recovered gas pipeline or the outlet pipeline of the recovered gas compressor are used to monitor the composition and flow rate of the recovered gas.

[0023] The hydrogen recovery pressure gauge and the return hydrogen flow meter installed on the high-pressure hydrogen pipeline are used to monitor the pressure and return flow of the recovered gas from the long-tube vehicle.

[0024] The recovered gas calculation module is connected to the raw material gas flow meter, hydrogen purification inlet analysis meter, recovered gas analysis meter and recovered gas flow meter, and is used to dynamically adjust the recovered gas flow based on monitoring data;

[0025] The product hydrogen calculation module is connected to the product gas analysis table, hydrogen purification inlet analysis table and return hydrogen flow meter, and is used to control the recovery or return hydrogen flow rate of unqualified product gas based on product gas quality.

[0026] A raw material gas flow regulating valve is installed on the raw material gas pipeline and is connected to the raw material gas flow meter for signal transmission.

[0027] A recovery gas flow regulating valve is installed on the recovery gas pipeline or the outlet pipeline of the recovery gas compressor and is signal-connected to the recovery gas flow meter and the recovery gas calculation module.

[0028] A return hydrogen flow regulating valve is installed on the high-pressure hydrogen pipeline and is signal-connected to the return hydrogen flow meter and the product hydrogen calculation module.

[0029] The non-conforming gas recovery shut-off valve and the non-conforming gas recovery regulating valve are installed on the non-conforming product gas recovery pipeline and are connected to the product gas analyzer signal.

[0030] Furthermore, one end of the high-pressure hydrogen pipeline is connected to the hydrogen recovery manual valve, and the other end is divided into two pipelines, wherein the first pipeline is connected to the raw material gas pipeline through the return hydrogen pipeline, and the second pipeline is connected to the desorbed gas pipeline through the low-pressure recovery pipeline.

[0031] Furthermore, a hydrogen pressure reducing valve is provided on the high-pressure hydrogen pipeline, and a pressure reducing bypass pipeline is connected in parallel at both ends of the hydrogen pressure reducing valve.

[0032] Furthermore, the non-conforming product gas recovery pipeline is connected to the fuel gas pipeline.

[0033] Furthermore, a branch line is also extended from the desorption gas line and connected to the fuel gas line.

[0034] A second aspect of the present invention is to provide a method for controlling the hydrogen recovery system of the hydrogen refueling mother station, the method comprising the following steps:

[0035] Real-time monitoring of the raw gas composition at the inlet of the hydrogen purification unit, the product gas composition at the outlet, and the recovered gas composition returning from the outlet of the recovered gas compressor;

[0036] Based on the monitoring results of the product gas components, the first control strategy is implemented: when the product gas is qualified, it is allowed to be filled into the long-tube truck; when the product gas is unqualified, the filling path is automatically cut off and the unqualified product gas is directed to the preset recovery or discharge pipeline.

[0037] Based on the monitoring results of the raw gas components and the recovered gas components, a second control strategy is implemented: dynamically adjusting the flow rate of the recovered gas returned to the raw gas through the recovered gas pipeline, so that the impurity concentration of the raw gas entering the hydrogen purification device after mixing is stabilized within a preset range.

[0038] Furthermore, the second control strategy is implemented through a recovery gas calculation module, which calculates and outputs the set value of the recovery gas flow rate based on the set value or measured value of the raw material gas components and the measured value of the recovery gas components, so as to control the corresponding recovery gas flow regulating valve.

[0039] Furthermore, the method also includes a third control strategy for handling situations where the concentration of impurities in the feed gas is abnormally high:

[0040] When the monitoring results of the product gas components show that the impurity concentration is close to the threshold due to the abnormality of the raw material gas, the high-purity hydrogen return path from the filling main pipe or qualified long pipe vehicle to the raw material gas pipeline is automatically opened.

[0041] Based on real-time monitoring data of the product gas composition and / or the mixed raw material gas composition, the flow rate of the returned high-purity hydrogen is dynamically calculated and controlled by the product hydrogen calculation module to dilute the impurity concentration in the raw material gas and ensure that the product gas at the outlet of the hydrogen purification device is consistently qualified.

[0042] Furthermore, the method also includes a fourth control strategy for the regeneration of the adsorbent within the hydrogen purification unit:

[0043] When it is determined that the adsorbent needs to be regenerated, a hydrogen circulation path is established from the filling main pipe or an external high-purity hydrogen source to the raw material gas pipeline.

[0044] The hydrogen purification device is flushed with high-purity hydrogen in a closed-loop or open-loop manner, and the regeneration effect is evaluated by monitoring the composition of the product gas until the adsorbent performance is restored.

[0045] Furthermore, when recovering hydrogen from the long-tube vehicle, the fifth control strategy is implemented:

[0046] Real-time monitoring of the pressure on the long tube vehicle or high-pressure hydrogen pipeline;

[0047] When the monitored pressure is higher than the raw gas pressure, the recovery path leading to the raw gas pipeline is opened, and the recovery path leading to the desorbed gas pipeline is closed.

[0048] When the monitored pressure is lower than the raw material gas pressure, the recovery path leading to the raw material gas pipeline is closed, and the bypass valve and the recovery path leading to the desorbed gas pipeline are opened.

[0049] The advantages and positive effects of this invention are:

[0050] 1. This invention utilizes purified hydrogen product gas, which is then compressed by a compressor and returned to the inlet of the hydrogen purification device to improve hydrogen purity. This avoids product defects caused by fluctuations in the composition of the raw material gas, thus ensuring the quality of the hydrogen product.

[0051] 2. This invention uses a non-compliance gas recovery pipeline to send purified non-compliance hydrogen to the fuel gas pipeline, reducing venting losses and improving economic efficiency.

[0052] 3. This invention uses a hydrogen pressure reducing valve to send substandard hydrogen from the long tube car to the inlet of the hydrogen purification device, thereby avoiding the venting of substandard gas and improving the hydrogen recovery rate.

[0053] 4. This invention utilizes a recovery gas compressor to recover a portion of the desorbed gas, thereby improving the hydrogen recovery rate of the hydrogen refueling mother station, ensuring the quality of the product gas, and enhancing the company's competitiveness.

[0054] 5. This invention can regenerate the device by using hydrogen or purified hydrogen from a long tube as a penetrating adsorbent, reducing downtime and ensuring a stable supply to downstream applications. Attached Figure Description

[0055] Figure 1 : Process flow diagram of the present invention;

[0056] Among them: P101-Hydrogen purification unit, C101-Product gas compressor, C201-Recovery gas compressor, S101-Oil filter, T1-Long tube car, 1-Raw material gas pipeline, 2-Product gas pipeline, 3-Compressor outlet pipeline, 4-Filling main pipeline, 5-Filling branch pipeline, 6-Desorption gas pipeline, 7-Recovery gas compressor outlet pipeline, 8-Recovery gas pipeline, 9-Fuel gas pipeline, 10-Product gas connection pipeline, 11-High pressure hydrogen pipeline, 12-Pressure reducing bypass pipeline, 13-Low pressure recovery pipeline, 14-Return hydrogen pipeline, 15-Unqualified product gas recovery pipeline, V1-Filling manual valve, V2-Recovery hydrogen manual valve, XV1-Product gas connection shut-off valve, XV2-Pressure reducing valve bypass shut-off valve, XV3-Medium Pressure recovery shut-off valve, XV4-low pressure recovery shut-off valve, XV5-unqualified gas recovery shut-off valve, XV6-filling main shut-off valve, PI1-raw material gas pressure gauge, PIC1-hydrogen recovery pressure gauge, FIC1-raw material gas flow meter, FIC2-recovery gas flow meter, FIC3-return hydrogen flow meter, AIC1-recovery gas analysis table, AIC2-product gas analysis table, AIC3-hydrogen purification inlet analysis table, KY1-recovery gas calculation module, KY2-product hydrogen calculation module, FV1-raw material gas flow regulating valve, FV2-recovery gas flow regulating valve, FV3-return hydrogen flow regulating valve, AV1-fuel gas regulating valve, AV2-unqualified gas recovery regulating valve, PCV1-hydrogen pressure reducing valve. Detailed Implementation

[0057] A hydrogen recovery system for a hydrogen refueling mother station, the process flow of which is as follows: Figure 1As shown, the raw material gas is connected to the inlet of the hydrogen purification unit P101 via raw material gas pipeline 1. A raw material gas flow meter FIC1, a raw material gas flow regulating valve FV1, a hydrogen purification inlet analyzer AIC3, and a raw material gas pressure gauge PI1 are installed sequentially on raw material gas pipeline 1. The product gas outlet of the hydrogen purification unit P101 is connected to the inlet of the product gas compressor C101 via product gas pipeline 2. A product gas analyzer AIC2 is installed on product gas pipeline 2. The product gas pipeline 2, connecting the outlet of the hydrogen purification unit P101 and product gas analyzer AIC2, is connected to the fuel gas pipeline 9 via a substandard product gas recovery pipeline 15. A substandard gas recovery shut-off valve XV5 and a substandard gas recovery regulating valve AV2 are installed sequentially on the substandard product gas recovery pipeline 15. The desorbed gas outlet of the hydrogen purification device P101 is connected to the inlet of the recovery gas compressor C201 via the desorbed gas pipeline 6. The recovery gas compressor C201 is a three-stage compressor. After the second stage of the recovery gas compressor C201, a stream of gas is drawn out and sent to the fuel gas network via the fuel gas pipeline 9. A fuel gas regulating valve AV1 is installed on the fuel gas pipeline 9. The outlet of the recovery gas compressor C201 is connected to the inlet of the oil filter S101 via the recovery gas compressor outlet pipeline 7. A recovery gas analyzer AIC1 and a recovery gas flow regulating valve FV2 are installed sequentially on the recovery gas compressor outlet pipeline 7. The outlet of the oil filter S101 is connected to the raw material gas pipeline 1 via the recovery gas pipeline 8. A recovery gas flow meter FIC2 is installed on the recovery gas pipeline 8. The outlet of the product gas compressor C101 is connected to the filling main pipe 4 via the compressor outlet pipeline 3. A filling main pipe shut-off valve XV6 is installed on the filling main pipe 4. The filling main pipe 4 is connected to the long pipe trolley T1 via multiple filling branch pipes 5. A filling manual valve V1 is installed on each filling branch pipe 5. One of the filling branch pipes 5 is selected as the route for hydrogen recovery. The filling branch pipe 5 is connected to one end of the high-pressure hydrogen pipeline 11 via the hydrogen recovery manual valve V2. The other end of the high-pressure hydrogen pipeline 11 is divided into two branches. The first branch is connected to the desorbed gas pipeline 6 via the low-pressure recovery pipeline 13. A low-pressure recovery shut-off valve XV4 is installed on the low-pressure recovery pipeline 13. The second branch is connected to the raw material gas pipeline 1 via the return hydrogen pipeline 14. A medium-pressure recovery shut-off valve XV3 is installed on the return hydrogen pipeline 14. A hydrogen recovery pressure gauge PIC1, a hydrogen pressure reducing valve PCV1, a return hydrogen flow meter FIC3, and a return hydrogen flow regulating valve FV3 are sequentially installed on the high-pressure hydrogen pipeline 11. A pressure reducing bypass pipeline 12 is connected to the high-pressure hydrogen pipeline 11 before and after the hydrogen pressure reducing valve PCV1. A pressure reducing valve bypass shut-off valve XV2 is installed on the pressure reducing bypass pipeline 12. The high-pressure hydrogen pipeline 11 and the filling main pipeline 4 are connected by a product gas connection pipeline 10. A product gas connection shut-off valve XV1 is installed on the product gas connection pipeline 10.

[0058] The raw material gas flow meter FIC1 is connected to the raw material gas flow regulating valve FV1 and transmits the signal to the recovery gas calculation module KY1 to control the raw material gas intake.

[0059] The recovered gas flow meter FIC2 is connected to the recovered gas flow regulating valve FV2 and transmits the signal to the recovered gas calculation module KY1 to control the recovered gas flow.

[0060] The recovered gas analyzer AIC1 is connected to the fuel gas regulating valve AV1 and transmits signals to the recovered gas calculation module KY1 to control the fuel gas flow rate.

[0061] The hydrogen purification inlet analyzer AIC3 is connected to the recovery gas calculation module KY1 and is used to monitor the component changes entering the hydrogen purification unit P101.

[0062] The product gas analyzer AIC2 is connected to the non-conforming gas recovery regulating valve AV2, the non-conforming gas recovery shut-off valve XV5, and the filling main pipe shut-off valve XV6, and transmits the signal to the product hydrogen calculation module KY2 to prevent non-conforming product gas from entering the long tube car T1 and contaminating the long tube car.

[0063] The return hydrogen flow meter FIC3 is connected to the return hydrogen flow regulating valve FV3 and transmits the signal to the product hydrogen calculation module KY2 to control the return hydrogen flow.

[0064] The hydrogen recovery pressure gauge PIC1 is connected to the pressure reducing valve bypass shut-off valve XV2, the medium-pressure recovery shut-off valve XV3, and the low-pressure recovery shut-off valve XV4 for signal control of the pressure and direction of unqualified hydrogen in the long tube vehicle.

[0065] The raw gas flow meter FIC1, the recovered gas flow meter FIC2, the hydrogen purification inlet analyzer AIC3, and the recovered gas analyzer AIC1 are connected to the recovered gas calculation module KY1 to control the composition of the raw gas to ensure that it does not exceed the standard.

[0066] The product gas analyzer AIC2, hydrogen purification inlet analyzer AIC3, return hydrogen flow meter FIC3, and the PLC control system of hydrogen purification device P101 are connected to the product hydrogen calculation module KY2 for signal control of product gas quality.

[0067] The flow meter, pressure gauge, and analysis meter are all online instruments, and these instruments, along with the recovery gas calculation module KY1 and the product hydrogen calculation module KY2, are all connected to the DCS system, which is used for overall control.

[0068] Example 1: Stable feed gas composition, only fuel gas recovery operation.

[0069] The recovery gas calculation module KY1 is set to "Mode 1", meaning it is in monitoring mode only. The raw material gas flow regulating valve FV1 is set to automatic. The operator can control the raw material gas inlet flow by inputting the set value of the raw material gas flow meter FIC1 through the DCS system. The hydrogen purification inlet analyzer AIC3 monitors the components in the raw material gas. The recovery gas flow regulating valve FV2 is manually closed, and the fuel gas regulating valve AV1 is manually fully opened. The hydrogen purification unit P101 and the product gas compressor C101 are running, and the recovery gas compressor C201 is running. The desorbed gas generated by the hydrogen purification unit P101 is compressed in two stages by the recovery gas compressor C201 and then recovered to the fuel gas pipeline through the fuel gas regulating valve AV1. The non-conforming gas recovery regulating valve AV2, product gas connection shut-off valve XV1, pressure reducing valve bypass shut-off valve XV2, medium pressure recovery shut-off valve XV3, low pressure recovery shut-off valve XV4, and non-conforming gas recovery shut-off valve XV5 are all in the closed state. The filling main shut-off valve XV6 and the filling manual valve V1 are in the open state. The product hydrogen purified by the hydrogen purification device P101 can be compressed by the product gas compressor C101 and filled into the long tube car T1 to complete the filling. Product gas analyzer AIC2 monitors the quality of the purified hydrogen from hydrogen purification unit P101. When the impurity content in the product hydrogen increases, the PLC control system adjusts the residence time and circulation time of the raw material gas to ensure the hydrogen product is qualified. When the product gas analyzer AIC2 monitors the product quality as unqualified, the unqualified gas recovery shut-off valve XV5 opens, and the unqualified gas recovery regulating valve AV2 controls the amount of gas sent to the fuel gas to prevent overpressure in the fuel gas pipeline. At the same time, the filling main shut-off valve XV6 immediately closes to prevent unqualified gas from entering the long tube car T1 and contaminating the hydrogen in the long tube car T1.

[0070] Example 2: Hydrogen recovery operation during start-up of hydrogen purification unit P101.

[0071] The recovery gas calculation module KY1 is set to "Mode 1", meaning it is in monitoring mode only. The raw material gas flow regulating valve FV1 is set to automatic. The operator can control the raw material gas inlet flow by inputting the set value of the raw material gas flow meter FIC1 through the DCS system. The hydrogen purification inlet analyzer AIC3 monitors the components in the raw material gas. The recovery gas flow regulating valve FV2 is manually closed, and the fuel gas regulating valve AV1 is manually fully opened. The hydrogen purification unit P101 and the recovery gas compressor C201 are running. The desorbed gas generated by the hydrogen purification unit P101 is compressed in two stages by the recovery gas compressor C201 and then recovered to the fuel gas pipeline through the fuel gas regulating valve AV1. The main filling pipe shut-off valve XV6, the filling manual valve V1, the product gas connection shut-off valve XV1, the pressure reducing valve bypass shut-off valve XV2, the medium-pressure recovery shut-off valve XV3, and the low-pressure recovery shut-off valve XV4 are all closed. The substandard gas recovery regulating valve AV2 and the substandard gas recovery shut-off valve XV5 are open. The substandard hydrogen purified by the hydrogen purification unit P101 is controlled by the substandard gas recovery regulating valve AV2 to control the amount of fuel gas, preventing overpressure in the fuel gas pipeline. The product gas analyzer AIC2 monitors whether the product quality is qualified. When the hydrogen product is qualified, the product gas compressor C101 is started, the main filling pipe shut-off valve XV6 and the filling manual valve V1 are opened, and the substandard gas recovery shut-off valve XV5 and the substandard gas recovery regulating valve AV2 are closed at the same time, and the filling operation can be carried out.

[0072] Example 3: Recovery of part of the desorbed gas.

[0073] The recovery gas calculation module KY1 selects "Mode 2", meaning that the recovery gas calculation module KY1 is set to recovery mode. The principle is as follows: Since the hydrogen purification unit P101 is designed with the parameter of the highest impurity content of the raw gas under abnormal conditions as the benchmark for the adsorbent loading, and the designed maximum load is generally 110% or 120%, there is a large amount of unused space in the hydrogen purification system under normal conditions. The emission of desorbed gas is mainly related to the volume of the adsorption tower and the circulation time. Therefore, the hydrogen content in the desorbed gas is still very high. Part of the desorbed gas can be recovered to the raw gas inlet, so that the impurity content of the raw gas is slightly higher than that of the actual raw gas. The excess desorbed gas can be discharged to the fuel gas pipeline through the unqualified gas recovery regulating valve AV2 to prevent impurities from accumulating in the system.

[0074] Since the composition of the feed gas is stable in most cases, the composition content of the feed gas is input into the recovery gas calculation module KY1 according to the daily offline analysis sampling data. The recovery gas flow rate is calculated by the recovery gas calculation module KY1 based on the data of the feed gas flow rate and composition, the data of the recovery gas analysis table AIC1, and the data of the hydrogen purification inlet analysis table AIC3 after mixing. This is used as the set value of the recovery gas flow meter FIC2. The unrecovered desorbed gas is discharged to the fuel gas pipeline network through the fuel gas regulating valve AV1 controlled by the recovery gas analysis table AIC1.

[0075] The feed gas flow regulating valve FV1 is set to automatic. Operators can control the feed gas inlet flow by inputting the set value of the feed gas flow meter FIC1 through the DCS system. The hydrogen purification inlet analyzer AIC3 monitors the components in the feed gas. The recovery gas flow regulating valve FV2 is set to automatic. The set value of the recovery gas flow meter FIC2 is calculated and set by the recovery gas calculation module KY1. The fuel gas regulating valve AV1 is set to automatic, and the recovery gas analyzer AIC1 controls the discharge of fuel gas to the fuel gas pipeline. The hydrogen purification unit P101 and the product gas compressor C101 are operating, as is the recovery gas compressor C201. Part of the desorbed gas produced by the hydrogen purification unit P101 is compressed in two stages by the recovery gas compressor C201 and then recovered to the fuel gas pipeline through the fuel gas regulating valve AV1. The remaining desorbed gas is recovered to the feed gas inlet through the recovery gas flow regulating valve FV2. The non-conforming gas recovery regulating valve AV2, product gas connection shut-off valve XV1, pressure reducing valve bypass shut-off valve XV2, medium pressure recovery shut-off valve XV3, low pressure recovery shut-off valve XV4, and non-conforming gas recovery shut-off valve XV5 are all in the closed state. The filling main shut-off valve XV6 and the filling manual valve V1 are in the open state. The product hydrogen purified by the hydrogen purification device P101 can be compressed by the product gas compressor C101 and filled into the long tube car T1 to complete the filling. Product gas analyzer AIC2 monitors the quality of the purified hydrogen from hydrogen purification unit P101. When the impurity content in the product hydrogen increases, the PLC control system adjusts the residence time and circulation time of the raw material gas to ensure the hydrogen product is qualified. When the product gas analyzer AIC2 monitors the product quality as unqualified, the unqualified gas recovery shut-off valve XV5 opens, and the unqualified gas recovery regulating valve AV2 controls the amount of gas sent to the fuel gas to prevent overpressure in the fuel gas pipeline. At the same time, the filling main shut-off valve XV6 immediately closes to prevent unqualified gas from entering the long tube car T1 and contaminating the hydrogen in the long tube car T1.

[0076] Example 4: Abnormal operating conditions of raw material gas.

[0077] This operating condition is due to instability in the upstream unit, which caused the impurity content in the raw gas to exceed the maximum designed impurity content, resulting in substandard product quality, unit shutdown, and supply interruption to downstream customers.

[0078] The recovery gas calculation module KY1 is set to "Mode 1", meaning it is in monitoring mode only. The raw material gas flow regulating valve FV1 is set to automatic. The operator can control the raw material gas inlet flow by inputting the set value of the raw material gas flow meter FIC1 through the DCS system. The hydrogen purification inlet analyzer AIC3 monitors the components in the raw material gas. The recovery gas flow regulating valve FV2 is manually closed, and the fuel gas regulating valve AV1 is manually fully opened. The hydrogen purification unit P101 and the product gas compressor C101 are running, and the recovery gas compressor C201 is running. The desorbed gas generated by the hydrogen purification unit P101 is compressed in two stages by the recovery gas compressor C201 and then recovered to the fuel gas pipeline through the fuel gas regulating valve AV1.

[0079] Manually open the product gas connection shut-off valve XV1 and the medium-pressure recovery shut-off valve XV3. Set the hydrogen pressure reducing valve PCV1 to return hydrogen pressure slightly higher than the feed gas pressure. Activate the product hydrogen calculation module KY2, meaning data from the product gas analysis table AIC2 and the hydrogen purification inlet analysis table AIC3 is transmitted to the product hydrogen calculation module KY2. The data from the product gas analysis table AIC2 is primary, and the data from the hydrogen purification inlet analysis table AIC3 is secondary. When the impurity content analyzed by the product gas analyzer AIC2 increases, the product hydrogen calculation module KY2 prioritizes controlling the PLC system of the hydrogen purification unit P101 to adjust the residence time and circulation time of the raw material gas to ensure the quality of the hydrogen product. When the PLC control system is adjusted to the shortest circulation time, if the impurity content of the product hydrogen is still too high, the product hydrogen calculation module KY2 calculates the return hydrogen flow rate based on the data analyzed by the raw material gas flow rate and the mixed hydrogen purification inlet analyzer AIC3. This return hydrogen flow rate is then used as the set value for the return hydrogen flow rate meter FIC3, ensuring that the impurity content analyzed by the hydrogen purification inlet analyzer AIC3 is close to the designed maximum impurity content range, and guaranteeing that the impurity content analyzed by the product gas analyzer AIC2 no longer increases, and that the product gas quality is qualified. The non-conforming gas recovery regulating valve AV2, pressure reducing valve bypass shut-off valve XV2, low-pressure recovery shut-off valve XV4, and non-conforming gas recovery shut-off valve XV5 are all closed. Opening the filling main shut-off valve XV6 and the filling manual valve V1 allows the purified product hydrogen from the hydrogen purification unit P101 to be compressed by the product gas compressor C101 and filled into the long-tube carriage T1, completing the filling process. The product gas analyzer AIC2 monitors the quality of the purified product hydrogen from the hydrogen purification unit P101. When the product gas analyzer AIC2 detects non-conforming product quality, the non-conforming gas recovery shut-off valve XV5 opens, and the non-conforming gas recovery regulating valve AV2 controls the amount of gas sent to the fuel gas pipeline to prevent overpressure in the fuel gas network. Simultaneously, the filling main shut-off valve XV6 immediately closes to prevent non-conforming gas from entering the long-tube carriage T1 and contaminating the hydrogen in T1.

[0080] Example 5: Recovery of substandard hydrogen from a long-tube vehicle.

[0081] When hydrogen in the long-tube filling vehicle becomes contaminated due to abnormal conditions, the gas can be recovered to the feed gas inlet or the desorbed gas. The specific operation is as follows:

[0082] Connect the substandard long tube vehicle T1 to the filling branch pipe 5, which can be connected to the high-pressure hydrogen pipeline 11. The filling manual valve V1 is closed. Open the recovery hydrogen manual valve V2. The product gas connection shut-off valve XV1 is closed. The hydrogen pressure reducing valve PCV1 is set to return hydrogen pressure slightly higher than the raw material gas pressure. The pressure reducing valve bypass shut-off valve XV2, the medium-pressure recovery shut-off valve XV3, and the low-pressure recovery shut-off valve XV4 are set to automatic operation. The hydrogen recovery pressure gauge PIC1 is set to the same value as the hydrogen pressure reducing valve PCV1. The return hydrogen flow meter FIC3 controls the return hydrogen flow regulating valve FV3 to ensure the flow rate does not exceed 500 Nm³. 3 When the pressure inside the substandard long tube car T1 is higher than the set value of the hydrogen recovery pressure gauge PIC1, the pressure reducing valve bypass shut-off valve XV2 and the low-pressure recovery shut-off valve XV4 are closed, and the medium-pressure recovery shut-off valve XV3 is open. When the pressure inside the substandard long tube car T1 is lower than the set value of the hydrogen recovery pressure gauge PIC1, the pressure reducing valve bypass shut-off valve XV2 and the low-pressure recovery shut-off valve XV4 automatically open, and the medium-pressure recovery shut-off valve XV3 automatically closes. The substandard hydrogen is discharged to the inlet of the recovery gas compressor C201 until the substandard gas in the substandard long tube car T1 is discharged to 0.1 MPa, and the recovery hydrogen manual valve V2 is closed. The remaining operations are performed according to "Example 1".

[0083] Example 6: Regeneration operation of hydrogen purification unit P101.

[0084] When the adsorbent in hydrogen purification unit P101 is breached due to excessive load or excessive impurities in the feed gas, the following steps can be taken to regenerate the adsorbent:

[0085] 1. When the adsorbent poisoning is not severe, regeneration can be achieved by increasing the hydrogen content at the feed gas inlet. The specific operation is as follows: The hydrogen purification unit P101, product gas compressor C101, and recovery gas compressor C201 are running. The recovery gas flow regulating valve FV2 is manually closed, and the fuel gas regulating valve AV1 is manually fully opened. The product gas connection shut-off valve XV1 and the medium-pressure recovery shut-off valve XV3 are manually opened. The hydrogen pressure reducing valve PCV1 is set to return hydrogen pressure slightly higher than the feed gas pressure. The feed gas flow regulating valve FV1 is set to automatic, and the operator inputs the minimum feed gas flow rate setting into the feed gas flow meter FIC1 through the DCS system. The product hydrogen calculation module KY2 is activated, meaning that data from the product gas analysis table AIC2 and the hydrogen purification inlet analysis table AIC3 are transmitted to the product hydrogen calculation module KY2. The data from the product gas analysis table AIC2 is primary, and the data from the hydrogen purification inlet analysis table AIC3 is secondary. The product hydrogen calculation module KY2 controls the PLC system of the hydrogen purification unit P101, adjusting the PLC control system to the shortest cycle time. The unqualified gas recovery regulating valve AV2, pressure reducing valve bypass shut-off valve XV2, low-pressure recovery shut-off valve XV4, unqualified gas recovery shut-off valve XV5, filling main shut-off valve XV6, filling manual valve V1, and recovered hydrogen manual valve V2 are all closed. The return hydrogen flow regulating valve FV3 is manually fully opened. The purified product hydrogen from the hydrogen purification unit P101 is then compressed through the product gas compressor. After compression by machine C101, the hydrogen product is returned to the raw material gas inlet through the product gas connection shut-off valve XV1, hydrogen pressure reducing valve PCV1, return hydrogen flow regulating valve FV3, and medium pressure recovery shut-off valve XV3. This causes the hydrogen content in the hydrogen purification inlet analyzer AIC3 to increase. The set value of the raw material gas flow meter FIC1 is adjusted until the hydrogen content in the raw material gas reaches the highest value. This cycle is maintained until the impurity content in the product gas analyzer AIC2 drops to the lowest value. The hydrogen cycle is maintained for 2 hours before refilling.

[0086] 2. When the adsorbent is severely poisoned, regeneration can be achieved through pure hydrogen circulation. The specific operation is as follows: The hydrogen purification unit P101, product gas compressor C101, and recovery gas compressor C201 are running. The recovery gas flow regulating valve FV2 is manually closed, and the fuel gas regulating valve AV1 is manually fully opened. The qualified hydrogen product long-tube vehicle T1 is connected to the filling branch pipe 5, which can be connected to the high-pressure hydrogen pipeline 11. The filling manual valve V1 is closed. The recovery hydrogen manual valve V2 is opened. The product gas connection shut-off valve XV1 and the medium-pressure recovery shut-off valve XV3 are manually opened. The hydrogen pressure reducing valve PCV1 is set to return hydrogen pressure slightly higher than the feed gas pressure. The raw material gas flow regulating valve FV1 is manually closed, and the PLC control system is adjusted to the shortest cycle time. The unqualified gas recovery regulating valve AV2, the pressure reducing valve bypass shut-off valve XV2, the low-pressure recovery shut-off valve XV4, the unqualified gas recovery shut-off valve XV5, the filling main shut-off valve XV6, and the filling manual valve V1 are all closed. The return hydrogen flow regulating valve FV3 is set to automatic, and the set value of the return hydrogen flow meter FIC3 is the same as the desorbed gas volume. The pure hydrogen in the long tube car mixes with the hydrogen compressed by the product gas compressor C101. The mixture is then returned to the raw material gas inlet via the product gas connection shut-off valve XV1, the hydrogen pressure reducing valve PCV1, the return hydrogen flow regulating valve FV3, and the medium-pressure recovery shut-off valve XV3. This cycle continues until the impurity content in the product gas analyzer AIC2 drops to its minimum value. The hydrogen cycle is maintained for 2 hours before resuming filling.

[0087] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept, and these all fall within the protection scope of the present invention.

Claims

1. A hydrogen recovery system for a hydrogen refueling mother station, characterized in that, It includes a hydrogen purification unit (P101), a product gas compressor (C101), a recovery gas compressor (C201), a long-tube carriage (T1), and online analytical instruments and flow meters installed on at least one pipeline; The inlet of the hydrogen purification device (P101) is connected to the raw material gas pipeline (1), its product gas outlet is connected to the inlet of the product gas compressor (C101) through the product gas pipeline (2), and its desorption gas outlet is connected to the inlet of the recovery gas compressor (C201) through the desorption gas pipeline (6). The outlet of the product gas compressor (C101) is connected to the filling manifold (4), which is connected to the long tube car (T1) through multiple filling branch pipes (5). The outlet of the recovery gas compressor (C201) is connected to the raw material gas pipeline (1) via the recovery gas pipeline (8); One of the filling branch pipes (5) is provided with a recovery branch, which includes a recovery hydrogen hand valve (V2) and a high-pressure hydrogen line (11); the high-pressure hydrogen line (11) can be selectively connected to the raw material gas line (1) or the desorption gas line (6). The product gas pipeline (2) is equipped with a non-conforming product gas recovery pipeline (15); A product gas communication pipeline (10) is also connected between the high-pressure hydrogen pipeline (11) and the filling main pipe (4), and a product gas communication shut-off valve (XV1) is provided on it. The system also includes: A product gas analyzer (AIC2) is installed on the product gas pipeline (2) to monitor the product gas composition; The raw gas flow meter (FIC1) and the hydrogen purification inlet analyzer (AIC3) installed on the raw gas pipeline (1) are used to monitor the raw gas flow rate and composition. The recovered gas analyzer (AIC1) and recovered gas flow meter (FIC2) installed on the recovered gas pipeline (8) or the recovered gas compressor outlet pipeline (7) are used to monitor the composition and flow rate of the recovered gas. The recovered gas calculation module (KY1) is connected to the raw material gas flow meter (FIC1), hydrogen purification inlet analysis meter (AIC3), recovered gas analysis meter (AIC1), and recovered gas flow meter (FIC2) for dynamically adjusting the recovered gas flow rate based on monitoring data. The product hydrogen calculation module (KY2) is connected to the product gas analysis table (AIC2) and is used to control the flow rate of hydrogen recovered or returned from unqualified product gas based on product gas quality control.

2. The hydrogen recovery system for a hydrogen refueling mother station according to claim 1, characterized in that, One end of the high-pressure hydrogen pipeline (11) is connected to the recovery hydrogen hand valve (V2), and the other end is divided into two pipelines. The first pipeline is connected to the raw material gas pipeline (1) through the return hydrogen pipeline (14), and the second pipeline is connected to the desorption gas pipeline (6) through the low-pressure recovery pipeline (13).

3. The hydrogen recovery system for a hydrogen refueling mother station according to claim 2, characterized in that, A hydrogen pressure reducing valve (PCV1) is provided on the high-pressure hydrogen pipeline (11), and a pressure reducing bypass pipeline (12) is connected in parallel at both ends of the hydrogen pressure reducing valve (PCV1).

4. The hydrogen recovery system for a hydrogen refueling mother station according to claim 1, characterized in that, The non-conforming product gas recovery pipeline (15) is connected to the fuel gas pipeline (9).

5. The hydrogen recovery system for a hydrogen refueling mother station according to claim 4, characterized in that, A branch line is also led out from the desorption gas line (6) and connected to the fuel gas line (9).

6. A method for controlling a hydrogen recovery system at a hydrogen refueling mother station as described in any one of claims 1-5, characterized in that, The method includes the following steps: Real-time monitoring of the raw gas composition at the inlet of the hydrogen purification unit (P101), the product gas composition at the outlet, and the recovered gas composition returning from the outlet of the recovered gas compressor (C201); Based on the monitoring results of the product gas components, the first control strategy is implemented: when the product gas is qualified, it is allowed to be filled into the long tube truck (T1); when the product gas is unqualified, the filling path is automatically cut off and the unqualified product gas is directed to the preset recovery or discharge pipeline. Based on the monitoring results of the raw gas components and the recovered gas components, a second control strategy is implemented: dynamically adjusting the flow rate of the recovered gas returned to the raw gas through the recovered gas pipeline (8) so that the impurity concentration of the raw gas entering the hydrogen purification device (P101) after mixing is stabilized within a preset range.

7. The method according to claim 6, characterized in that, The second control strategy is implemented through the recovery gas calculation module (KY1), which calculates and outputs the set value of the recovery gas flow rate based on the set value or measured value of the raw material gas component and the measured value of the recovery gas component, so as to control the corresponding recovery gas flow regulating valve (FV2).

8. The method according to claim 6, characterized in that, The method also includes a third control strategy for handling situations where the concentration of impurities in the feed gas is abnormally high: When the monitoring results of the product gas components show that the impurity concentration is close to the threshold due to the abnormality of the raw material gas, the high-purity hydrogen return path from the filling main pipe (4) or the qualified long pipe vehicle (T1) to the raw material gas pipeline (1) is automatically opened. Based on real-time monitoring data of the product gas composition and / or the mixed raw material gas composition, the flow rate of the returned high-purity hydrogen is dynamically calculated and controlled by the product hydrogen calculation module (KY2) to dilute the impurity concentration in the raw material gas and ensure that the product gas at the outlet of the hydrogen purification device (P101) is continuously qualified.

9. The method according to claim 6, characterized in that, The method also includes a fourth control strategy for regenerating the adsorbent within the hydrogen purification unit (P101): When it is determined that the adsorbent needs to be regenerated, a hydrogen circulation path is established from the filling main pipe (4) or an external high-purity hydrogen source to the raw material gas pipeline (1); The hydrogen purification device (P101) is flushed with high-purity hydrogen in a closed-loop or open-loop manner, and the regeneration effect is evaluated by monitoring the composition of the product gas until the adsorbent performance is restored.

10. The method according to claim 6, characterized in that, When recovering hydrogen in the long tube car (T1), the fifth control strategy is executed: Real-time monitoring of the pressure on the long tube vehicle (T1) or the high-pressure hydrogen pipeline (11); When the monitored pressure is higher than the raw gas pressure, the recovery path leading to the raw gas pipeline (1) is opened and the recovery path leading to the desorbed gas pipeline (6) is closed. When the monitored pressure is lower than the raw gas pressure, the recovery path leading to the raw gas pipeline (1) is closed, and the bypass valve and the recovery path leading to the desorbed gas pipeline (6) are opened.

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