I’m seeking advice from everyone regarding issues with ethylene plants
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I am about to start working on a new unit (switching from a sequential separation process to a pre-depropanization pre-hydrogenation process), and I hope that those with experience can offer guidance regarding the specific tasks involved. Thank you very much! In particular, the special circumstances in the startup preparation and actual operation of the furnace, rapid cooling viscosity reduction tower, propane removal tower, and pre-hydrogenation reactor. I only have a basic understanding of this; I really appreciate it if my friends could offer some guidance!
The sequence of hydrogenation before pre-depropanization involves only changes in the separation process; the quenching section of the furnace remains unchanged
To prevent CO poisoning in the upstream hydrogenation reactor, pre-sulfurization of the furnace tubes is required before feeding material, which is not necessary in a sequential process.
I believe the key operating points for the front hydrogenation reactor are as follows: 1. The reactor can be put into operation only after the top temperature of the high-pressure depropanization column is within the specified range (generally, the dibutylene level should be less than 1000 ppm). 2. Before feeding, it has been properly reduced using methane hydrogen or hydrogen, and N2 has been used for purging to room temperature. 3. Before feeding the material, first charge it with high-pressure N2, and then with high-pressure gaseous ethylene (pay attention to the temperature of the ethylene during charging). 3. During feeding, the temperature increase at the inlet of each section should be gradual.
There’s no difference between a furnace and a quenching system. Compared to sequential separation, the C2 hydrogenation reactor does not require hydrogen injection, as hydrogen is already present in the pyrolysis gas. Propane removal generally involves two columns: high-pressure and low-pressure.