Do you have experienced technicians for hydrogen production from coking dry gas to answer questions?
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When our hydrogen production plant is shut down, after the feed to the conversion system is cut off, steam is still supplied for 15 minutes as a purge, followed by cooling and gas displacement; it can be assumed that the conversion catalyst is in a reduced state during shutdown, right? When restarting, there are two arguments: one is that hydrogen should be stored using PSA during the shutdown period, and then this stored hydrogen can be used to properly reduce the conversion catalyst upon restart ； One approach is to avoid storing hydrogen; instead, steam is supplied at the start of operation, followed by the introduction of coking dry gas promptly, which shortens the startup time. However, the load must be kept low at the beginning. Which of the two should I choose? Please, experts, give me your advice!
Theoretically, the PSA requires a gas storage catalyst to be reduced, but in practice, a small amount of gas is introduced directly. It’s unlikely that there is only one gas source in your system; normally, there should be a supply of natural gas as well. At the start up phase, hydrogen is produced using natural gas for a while, after which dry gas is gradually added, and this way there are no issues
In the case of an emergency shutdown that is resolved within 15 minutes, feeding can resume immediately; if possible, it is best to use natural gas first. But during normal shutdown, doesn’t the catalyst need to be fully oxidized?