I have two questions regarding delayed coking
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The process is as follows: residue oil – raw material storage tank – distillation tower – heating furnace – coke tower – distillation tower – enrichment gas compression – absorption and stabilization. First question: The residue oil heating furnace has reached the reaction conditions; why doesn’t the reaction start before it enters the coke tower? (This is a question asked by the interviewer during a company interview I had today.) Another question: What does “delayed” mean in delayed coking? Is it called “delayed coking” because the heavy oil separated by the fractionation tower is returned to the feed section as recycled oil for further coking, in order to increase the production of light oils? Thank you all!
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Personal understanding: First, the reason why the residue oil in the heating furnace reaches the coking temperature but does not react is as follows: 1, the flow rate of oil and gas inside the furnace tubes is very high; 2, the injection of water vapor delays the occurrence of coking in the residue oil. Secondly: Referring to the first explanation, delay, as the name implies, means slowing down the coking of residue. This involves slowing down the coking process within the furnace tubes as well as controlling the degree of coking of the residue.
At that time, the interviewer asked two questions back to back, so perhaps that’s why as well. I’ll check the relevant information again. Thank you very much!
First question: The residue heater has reached the reaction conditions; why hasn’t the reaction started before it enters the coke tower? Answer: The residuum does not stay in the furnace tube long enough—less than 45 seconds—to reach the reaction conditions, so no reaction occurs ； In fact, some reaction has already taken place; otherwise, how could the furnace tube coking? Another question: What does “delayed” mean in delayed coking? Answer: The raw residue oil passes through the heating furnace tubes at a high flow rate, being rapidly heated to a temperature of 490–505°C suitable for deep reactions, after which it immediately enters the coke tower where it stays for a sufficient amount of time to undergo thermal cracking and condensation reactions. Since the coking reaction does not take place in the heating furnace tubes but is delayed until the coke tower, delayed coking is thus named. Its characteristic is that it is both coking and non-coking. That is, coking occurs in the coke tower, rather than in the furnace tubes and other areas.
Agree with the explanation above! ! ! ! ! ! ! By \"delay,\" it means delaying the reaction until it takes place in the coke tower; if the reaction occurred in the heating furnace, the furnace tubes would have coked up long ago!!!!
Thank you, I finally understand a bit better. From the beginning, there was no in-depth understanding of it
Actually, the two questions posed by the examiner are essentially one question: the reaction material reaches 495 degrees in the heating furnace, the line speed is very high, the residence time is short, so the reaction is delayed to take place in the coke tower! ! ! ! ! 1
Inside the furnace tube, pyrolysis releases heat, raising the temperature to 490–500 degrees; water or gas is injected into the furnace tube to increase the linear velocity of the circulating oil, thereby delaying the condensation reaction (which is exothermic) until it takes place in the coke tower where coke is formed. The oil and gas then proceed to the distillation tower via the vaporization line for product separation.
Unless something unexpected happens, this issue relates to the recruitment of operators for Sinochem Quanzhou Coking. Still, quite a number of candidates who took the interview performed poorly; P
Any operator who has worked in a coking plant should be able to answer this; it’s the most basic thing one should know. 5th floor is correct.