What should be done with the PSA section after the natural gas-based hydrogen production plant is shut down?

When the natural gas-based hydrogen production plant is shut down normally or experiences a short-term shutdown due to an emergency, the following actions must be taken to handle the PSA section: 1. Stop feeding: Close the natural gas supply pipelines and valves to halt the inflow of natural gas. 2. Pressure relief: Release the high-pressure gas in the PSA system by opening the exhaust valve to discharge it to a safe location, or reduce the system pressure through other methods. 3. Hydrogen recovery: After decompression treatment, an adsorbent is used to re-adsorb hydrogen. The hydrogen adsorbed in the adsorbent is separated and stored in a suitable container. 4. Cleaning and maintenance: Clean and maintain the PSA system, including removing contaminants and waste gases from the adsorbent, as well as inspecting and replacing damaged components. 5. Inspection and maintenance of equipment: Inspect and maintain other equipment and systems in the natural gas hydrogen production facility to ensure their proper operation. During operation, it is necessary to comply with relevant safety procedures and operation manuals, and to follow the recommendations of the equipment manufacturer strictly. If you encounter complex situations or have special requirements, it is recommended to seek the help and guidance of professionals. .

For a short-term shutdown, just ignore it and maintain the current PSA shutdown status； In the event of a long-term shutdown, the materials in each adsorption tower should be drained one by one into the low-vacuum system, after which the system can be purged with nitrogen to ensure that the concentration of combustible materials remains at ≤0.2%, while the system is kept at a slight positive pressure

During short-term shutdowns, do the inlet and outlet valves of the adsorption tower need to be closed? (Adsorbed gas and produced hydrogen)

Is the hydrogen being recovered the hydrogen from the medium-temperature converter? Could you explain the detailed steps for recovering hydrogen?

1. For short-term shutdowns, it is sufficient to maintain the current PSA pressure level； 2. For prolonged shutdowns, the material in each adsorption tower should be drained one by one into the low-pressure system, at a pressure of around 0.05 Mpa; thereafter, the system can be purged with nitrogen to ensure that the concentration of combustible materials is ≤0.2%, while maintaining a slight positive pressure in the system. 3. Blind the pipeline valves before and after PSA.

Suspend operations temporarily and close the inlet and outlet valves to prevent cross-contamination. The entire system must be at positive pressure.

No need to go through the hassle; a short shutdown is sufficient – just pause the PSA program. However, it is necessary to close the inlet and outlet valves of the PSA system. Once the system has recovered and the outlet parameters are within acceptable limits, open the PSA inlet and outlet valves; then the PSA program can be run.