In hydrogenation units, if the compressor stops operating suddenly, why is it necessary to stop feeding material as well?
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If the compressor in a diesel hydrogenation unit suddenly stops operating, feed supply is generally halted immediately. I would like to ask experts: if I replace the substandard oil so that the furnace temperature drops, can I continue feeding without stopping? What are the consequences of continuing to feed?
It is mainly to prevent the reactor from overheating and catalyst coking. After the compressor stops operating, there is no circulating medium left; even if the heating furnace is turned off, the heat in the reactor will not dissipate. If feeding continues at this point, exothermic reactions will proceed, leading to a spike in temperature.
The compressor is shut down; the fluidity of the medium within the system is poor, preventing heat from being removed in a timely manner. Continuing to feed material can lead to excessive temperature rises, catalyst coking, and other hazards
When the hydrogen circulation pump stops operating, the heat generated by the reaction cannot be dissipated; continuing to feed material has no practical sense. To stop feeding material, simply shut down the new hydrogen pump and switch to a closed-loop system~~~
When the circulation pump stops operating, it normally triggers interlocks for the heating furnace and the feed pump; in other words, the heating furnace shuts down and the feed pump stops running, all to prevent excessive temperature rise in the reaction reactor； If feeding continues, the reaction will continue to release heat, posing a risk of excessive temperature rise, which can lead to catalyst deactivation as well as overheating and overpressure in the reactor. If the new hydrogen generator is shut down, the impact is much smaller; simply start the backup generator.
Circulating hydrogen compressors are generally interlocked with feed pump heaters; if the circulating hydrogen compressor stops operating, the feed pump must also stop to prevent the reactor from overheating and coking. When restarting the cyclic hydrogen unit, be careful to drain the oil from the inlet pipeline first; otherwise, the dry gas seal of the cyclic hydrogen machine will be damaged.
The first step after shutting down the compressor should be to shut off the feed stream in order to prevent overheating of the reaction. If the pressure of fresh hydrogen is sufficient, it can be directed to the compressor outlet to maintain the hydrogen flow rate. Since there is no cold hydrogen available to control the bed temperature after the compressor is stopped, continuing to feed material will generate heat and could lead to overheating. However, if cold oil is used to control the bed temperature, the cold oil supply should be turned up to full capacity to lower the bed temperature before stopping the pump
The patent holders for various process packages have different approaches; in some cases, after the cyclic hydrogen compressor stops operating, the heating furnace is also shut down, but the feed continues to flow for a certain period of time to allow the oil to cool down.