For the hydrocracking unit under emergency pressure relief and cooling, should feeding be stopped immediately?
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For the hydrocracking unit under emergency pressure relief and cooling, should feed be cut off immediately, or wait until the specified non-reactive pressure is reached before cutting off the feed?
Our operating procedures require that the feed flow not be stopped, as this allows the feed to continue carrying away heat and thus help to reduce the temperature; the feed is only stopped once the pressure has dropped to a level where no reaction can occur. Another approach is to stop the feed flow immediately, as the absence of reactants will prevent any reaction from taking place. Which method is better? We follow the first method; we noticed that the temperature was about to get too high
Emergency pelletizing is required; otherwise, the high-pressure airflow will carry the liquid phase into the low-voltage system, resulting in the discharge of liquid from that system and causing a fire storm, which poses a serious safety hazard
That won’t happen; we carry out emergency pressure relief after reaching high temperatures, so it won’t lead to the situation you mentioned. Right now, the main focus is on analyzing things from a safety perspective – determining whether it’s easier to control the reaction temperature by shutting off or not shutting off the feed
All emergency venting occurs at high pressures; since the gas flow velocity is too fast during emergency venting, the liquid cannot be completely condensed, and a portion of it is released along with the gas stream to the flare!
I haven’t encountered this issue; then, purely from the perspective of safe cooling, which method will yield better results?
By emergency pressure relief, do you mean manual interlocking or automatic interlocking? Also, how is the interlocking system configured in your facility? During emergency pressure relief, is it a complete shutdown or not?
Emergency pressure relief is activated when the bed temperature can no longer be controlled by conventional methods, and it works the same whether automatically or manually. High bed temperature or too low circulating hydrogen can both trigger an emergency pressure release. If all the pressure is released, everything will definitely stop – how could it not stop?
Different patent holders have different design concepts; those I’ve come across include both feed pumps that stop operating and those that continue to operate, and all of them are effective at reducing the temperature.
The feed pump must be stopped; otherwise, when the circulator is started, it will cause stress on the feed heat exchanger.
We stop feeding immediately when pressure is relieved, reducing the reaction pressure to its lowest level