Discussion on the causes of coking in the process water heater of ethylene plants
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Experts, internal leakage was detected during the operation of the process water heat exchanger in the ethylene plant. Upon disassembly, severe coking was found inside the tube bundle. This heat exchanger is used to heat the process water with medium-pressure condensate; the process water flows through the tubes from top to bottom, while the condensate flows through the shell from bottom to top. The coking material inside the tube bundle is very hard, and the coking in the upper part is not as severe as that in the lower part. Analyze several possibilities: 1. The oil content in the process water is too high, resulting in polymerization upon heating (poor performance of the coalescer, inadequate separation of oil and water phases) ； 2. Hydrocarbons in process water (at normal levels) tend to polymerize at this temperature. I would like to ask the experts about the polymerization mechanism of hydrocarbons in process water, or whether anyone else is facing the same issue; I am very grateful.
Pygmalion gasoline contains a high level of olefins, which makes it highly prone to polymerization； Coking in the process water heat exchanger is a very common problem; the key is to slow down the occurrence of coking, and the main approach is to control the issue of oil presence in the emulsified process water
It is possible to consider combining demulsification and polymerization inhibition methods for improvement. I agree with the opinion above; if further discussion is needed, you can add me on QQ at 627339853
The dry point of pyrolysis gasoline is too high, and the styrene content in the process water is too high, resulting in polymerization upon heating. Toluene can be used as an extractant to remove styrene from the process water, with excellent results.
What is the temperature at which coking occurs? What is the temperature of the condensed water? Is it caused by an excessively high temperature of the condensed water?
Toluene can be used for extraction first, and it yields good results