Seeking advice on control schemes for coil reflux flow

Thread Content

This post was last edited by winnerhe on 2018-3-7 at 16:01. ======= Complaint: When posting on a mobile app, the topic and content end up in reversed order... It’s only possible to edit them again using a computer... ======= In some distillation columns, such as those used for propane removal in NGL processes, the flow controller for the condensate reflux at the top of the column is of the single-loop type; the liquid level in the condensate reflux tank is controlled in a cascade manner along with the flow rate of the propane distillate. In some cases, however, the flow control of the overhead distillate is a single loop, while the liquid level control of the condensation reflux tank and the reflux control are in cascade. I would like to ask, what are the criteria for choosing between these two control schemes? What is the reflux ratio? What are the purity requirements for the product quality at the top of the tower?