Crude Tower Pumparound Tray Efficiency
Crude Tower Pumparound Tray Efficiency
(OP)
I have been told by many experts that the pumparound trays in a crude tower have a 30% efficiency at the most. However, my crude tower simulation shows that the pumparound trays efficiency should be between 45-55% to match the pumparound duty in the middle and the bottom pumparound. In the top pumparound the efficiency is 90%! Anything less will increase the top pumparound duty to "incredible" proportions. Does anyone has experience in determining pumparound tray efficiency? What is the expected efficiency for the flash zone tray? To match distillation data, my simulation shows a 60% efficiency.





RE: Crude Tower Pumparound Tray Efficiency
Make your simulation life easy and model all trays as theoretical stages. Apply your efficiency corrections external to the model.
Good luck!
RE: Crude Tower Pumparound Tray Efficiency
Most people would agree that the pumparound's only purpose is to remove heat. However, I was being influenced by Lieberman's opinion that the pumparound trays do fractionate up to a point. He suggests that increasing pumparound rate increases fractionation (and efficiency) up to the incipient flood point. Thereafter, efficiency drops and fractionation deteriorates. I thought that the fact that I can't match the pumparound duties following the rules of thumb proved this point.
In my simulation, I even tied up the gap between the naphtha-kero and kero-diesel to the middle and lower pumparound rate. It worked for my base case, but even though I have a mass and energy balance within 4% of the actual values I am not sure if the simulation will work under other conditions.
I will keep trying.
RE: Crude Tower Pumparound Tray Efficiency
Greg