Problems with distillation towers
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We have a atmospheric distillation column, and during its recent commissioning, the pressures at the top and bottom of the column were normal. The temperatures at the top and above the middle section were much higher than usual, whereas the temperature at the bottom was much lower than normal. We’re not sure of the reason for this; we request assistance from colleagues in analyzing the situation! Thank you!
The composition of crude oil has changed, with more light components.
What changes have occurred in bottom heating? What are the changes in the temperature and flow rate of the reflux? Is there an intermediate reboiler?
"The person from the Central Plains said clearly that the composition inside the tower has changed. ----The temperatures at the top of the tower and above the middle section are much higher than before – there is more heavy fraction at the top of the tower. Meanwhile, the temperature at the bottom of the tower is much lower than normal, with more light fraction present at the bottom; sampling and analysis will make this clearer.
It’s likely that there has been a change in the composition inside the tower; taking a sample for analysis will clarify things.
Again, with constant pressure, the temperature should be related to the composition of the raw materials; in your case, it’s likely that a change in the composition of the raw materials is to blame, perhaps due to an increase in the amount of intermediate components.
Spring has arrived, and the weather is getting hotter. Hehe, try to increase the reflux within the operational limits in order to improve the separation efficiency. Changes in the composition of the feed material will affect the overall distribution within the tower. In any case, if the variations in composition are too large and exceed the designed separation efficiency, then it’s necessary to focus on maintaining either the top or the bottom product of the tower – that’s the product that can be preserved
I have also experienced this situation. At first, I thought it was due to operational issues, so I observed for some time to rule out those problems; the feed composition didn’t change either, but the temperature was still high in the upper part of the tower and low in the lower part. Eventually, it was determined that the problem was related to the equipment. All the trays above the feed tray of the tower have fallen off. If you have two or three feed plates, you can try changing them to see if there are any significant changes in the feed components, and also check the feed temperature
Measure the pressure difference of the tower in segments to take a look.