Distillation operation
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The dry point at the top of the tower is higher than the wet point at the bottom of the tower; how should this be handled?
For the same distillation column with packing, the boiling range of the product at the top of the column is 75–120, while that of the product at the bottom is 115–175; is there any overlap in these ranges?
Are you referring to the discharge flow rate?
If what you have here is flow rate, then that’s definitely not correct; usually, the product comes out at the top, while the by-products come out at the bottom – more at the top and less at the bottom
It seems they are talking about temperature. The process is correct at this temperature; this is merely the controlled temperature range, and at this temperature it can be adjusted using the existing equipment. In fact, during operation, the temperature fluctuation in a distillation tower is very small, within 1 degree or so. What you mentioned cannot coincide with reality during actual operation.
【For the same distillation tower with packing, the boiling range of the top product is 75–120, while that of the bottom product is 115–175; isn’t there overlap in these ranges?】 According to what the poster said, the dry point at the top of the tower is higher than the initial boiling point at the bottom, which indicates that there is overlap in the product ranges. Such overlap shows that the separation process is not precise enough; in this case, the temperature at the top of the tower should be reduced and the reflux rate increased. Judging from the distillate composition, it should be a separation of heavy naphtha and light naphtha. I’m sorry, senior; please correct me.
An overlap control within 10 degrees should be normal, right?