Sudden decrease in the propylene content of liquid hydrocarbons in the catalytic cracking unit
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Recently, the propylene content in the liquid hydrocarbons from the catalytic cracking unit has dropped suddenly, with no significant fluctuations in operations. I would like to hear from experts – what could be the possible reasons?
Is it the low bed temperature that increases the hydrogen transfer reaction, resulting in a decrease in olefins? What are the levels of ethylene and butene?
Is it the low bed temperature that increases the hydrogen transfer reaction, resulting in a decrease in olefins? What are the levels of ethylene and butene?
Has there been any change in the raw materials? Under the same operating parameters, does a change in raw materials still have an impact on product quality?
In my opinion, it’s also due to the crude oil used; our propylene yield has increased significantly these days, and the reason for that is the change in the type of crude oil
Is the reaction temperature too low?； Has the reaction pressure increased? ； Has the catalyst activity decreased? ； Has the preheating temperature of the raw materials been reduced? ； Does the temperature of the vaporized steam change? ； Has the vapor pressure of the mist decreased or has the flow rate fallen? ； The issue with propylene is mainly related to the reaction process.
The propylene yield decreases; if there are no significant fluctuations in the reaction conditions, it is necessary to consider the activity of the equilibrium catalyst, or whether the catalyst has been adjusted. Additionally, factors such as the operation of the stabilizer tower – whether C2 compounds are present in it, and frequent pressure releases – also play a role