Status of the inlet and outlet of the circulator during hydrocracking power outage
Thread Content
This post was last edited by jcshsyy on 2016-4-15 17:04. Does it need to be immediately closed when there is a power outage in hydrocracking? Some sources state that it should be shut down immediately to prevent gas from flowing back during pressure release and thus damaging the dry gas seal, while other sources say this is not necessary. Which approach is the correct one?
It’s probably to be on the safe side; why would there not be more than one check valve at the outlet of the circulation pump, given the high pressure?
When there is a power outage, we close the high-to-low valves as well as the valves on equipment such as furnaces right away; the pressure difference of the circulating hydrogen isn’t too high, so we only close the inlet and outlet valves when we have time
Is the circulation machine motor-driven? Our turbines drive it; the gas station has a backup power source, so it continues to operate even in case of a power outage
After reading the original poster’s question, I can only discuss it from the perspective of sealing. The outlet pressure of a circulating hydrogen compressor is generally quite high; during normal operation of the unit, the seal is subjected to the inlet pressure. When the compressor shuts down abnormally, the outlet pressure returns to the inlet level, and the pressure acting on the seal at this time is what is known as the stagnation pressure. Seals are capable of withstanding this pressure. Regarding the concern about preventing gas from flowing back and damaging the dry gas seal, my understanding is as follows: during normal operation, the air for the first stage of the dry gas seal comes from the compressor outlet, and it is fed into the dry gas seal control system through processes such as liquid removal, filtering, and pressure reduction, with the aim of providing a clean working environment for the first stage seal. If the unit shuts down abnormally, the pressures at the inlet and outlet of the unit become roughly equal, and no pressure difference exists to push air into the first stage seal. In such cases, an automatic booster pump is activated to increase the pressure of the seal air and inject it into the unit. The most common cause of failure in the dry gas seal of circulating hydrogen compressors is, according to statistics, the presence of liquid in the sealing gas, which leads to damage to the dry gas seal. Since there are many aspects that are not clear, I’ll stop at this for now. If needed, please send it by mail to hyhuning@163.com
If the cycle hydrogen compressor loses power and the pressure difference between the inlet and outlet is low, the booster pump will start automatically, which will ensure an adequate flow of sealing gas; it seems that the process gas will not flow back into the sealing system
Self-protection function disabled to prevent the compressor from reversing!