Is there anyone skilled in fractionation? I have a question
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Why did the temperature at the light diesel extraction point of the catalytic fractionation tower drop sharply, only to rise again later? The curve shows a very steep variation. The temperatures of the other trays are normal; for example, the extraction temperatures at the first and second intermediate trays have not changed. Are there any experts in fractionation?
⒈Carefully check whether the trays have salt buildup, report to the unit’s management, and request that the tower be cleaned； ⒉The raw materials have changed, with more light components present; operations need to be adjusted.
1. Is light diesel used as a reabsorbent and returned to the 20th stage of distillation, with large flow fluctuations? 2. If salt builds up on the tray, wash the tower immediately.
There may be the following reasons: 1. A sudden increase in the amount of stripping steam or water entrainment； 2. Fluctuations in the top circulation volume or cold return flow volume and water carryover ； 3. Changes in the temperature or flow rate of the material returning to the tower in Unit 1 ； 4. The diesel extraction line was blocked; it became unobstructed after excess fluid accumulated.
Let’s continue the discussion. A new situation arose: at 3:00 p.m., the temperature at the top of the tower suddenly dropped. The temperature in the top circulation loop decreased by nearly 20 degrees within 15 minutes, while the temperature at the top of the tower fell by almost 9 degrees. The temperature of the cleaned diesel also dropped by 10 degrees. Only the temperature of the fluid drawn from the top circulation loop decreased slightly after a two-minute delay, before rising sharply and returning to normal on its own. During this process, the temperatures of the other trays remained normal. We had cleaned the tower a couple of days ago, and this kind of situation occurs only occasionally now. I think it might be a problem with the three-way valve in the top circulation system, or there was some fluctuation at that moment
1. Instrument issue. 2. The pipeline is not flowing properly. 3. Backflow with water