Pressure control after shutdown of the diesel hydrogenation cycle machine
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Question: In the case of an emergency shutdown of the circulator in a diesel hydrogenation unit and the activation of the emergency pressure relief procedure, what pressure level is appropriate for the system?
The discharge temperature to the bed layer does not exceed the set requirement.
Considering the bed temperature, there is no need for significant pressure relief as long as it doesn’t rise too quickly; after all, it’s money at stake. If the pressure is reduced too much, it will be troublesome to increase the pressure again when operations resume
It is determined based on the temperature rise of the bed layer; there is a interlock between the recycle hydrogen compressor and the feed pump, and if the feed pump does not stop, it must be stopped manually.
In the event of an accident requiring emergency pressure release, it must be released completely. If it’s a shutdown, there’s no need to release pressure.
After the circulator is shut down urgently, the feed pump stops operating, the heating furnace is turned off, and the desulfurization lean amine pump for recycled hydrogen ceases to function. To control the bed temperature, the device underwent emergency pressure relief, and the new hydrogen generator was manually shut down; new hydrogen was supplied to the system at the pressure of the pipeline network. If the pressure is not controlled properly, catalyst reduction is likely to occur; therefore, it is necessary to find an appropriate pressure level.
Addition: Since a rapid recovery was considered, the pressure was not fully released, and nitrogen was not used for displacement.