Regarding the discharge from the ethylene plant
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The company has built a new ethylene plant, and the towers and vessels in the heat and cold separation system are not equipped with high-pressure nitrogen lines. As to how material should be drained during design, the answer given was to use high-pressure rubber hoses connected to the DN20 nitrogen fitting at the service station for draining the material. Such an answer left me speechless. Use a DN20 nitrogen blowout head to remove the material; even if it’s removed until everything is gone, there will still be some left. I’m curious about the design for discharging material from ethylene plants among those in the industry – what it involves and how effective it is. I invite experts to share their insights.
I’m glad to see peers in the ethylene field, but unfortunately I specialize in compression, so I don’t know much about cold separation and heat separation; I could only come here to offer my support!
I’m not very familiar with cracking and separation
I’m not quite clear about your question. By \"returning the material,\" do you mean emptying and replacing it? In that case, no special arrangements should be necessary. Also, you haven’t specified whether the processes in your cold zone and hot zone involve pre-dehydrogenation or post-dehydrogenation, pre-cooling or post-cooling, or high-pressure demethanization or low-pressure demethanization; therefore, it’s difficult to determine exactly what needs to be done
“In the case of material return, it is necessary to first evacuate the air over night, then reduce the pressure to 2–3 KG, and finally replace the air with nitrogen. What is the purpose of using high-pressure nitrogen?” Since it is a process of returning materials, the liquid can be transported using a pump; the pressure is released into the flare line. Why can’t high-pressure nitrogen be used to send the gaseous hydrocarbons back into the spherical tank? Moreover, when the pressure needs to be reduced to 2–3 KG, medium-pressure nitrogen can be used for purging. But if only DN20 nitrogen lines are used for purging the system, how long will it take? Additionally, how long does it take for your facility to come to a stop?