DETERMINE THE OPERATING PRESSURE o Determine the bubble point temperature of the distillate Tbb=Tcw+△Tmin o Calculate the bubble point pressure ePbb=∑Paui(Tbub)xli Do same for the bottoms- determine tbbub and Pbbub In order to be able to condense the overhead vapor we must have pcol> pdbub And to reboil the bottoms we need Pbbub Pcol So, choose Pcol such that Pdbub Pcol Pbbub o Inot, either choose utilities with a wider temperature range or relax the separation specs 9/2799 Simple distillation design9/27/99 Simple Distillation Design 6 DETERMINE THE OPERATING PRESSURE u Determine the bubble point temperature of the distillate ð Tdbub = Tcw + D Tmin u Calculate the bubble point pressure ð Pdbub = å Psat,i(Tdbub) xdi u Do same for the bottoms- determine Tbbub and Pbbub u In order to be able to condense the overhead vapor we must have Pcol > Pdbub u And to reboil the bottoms, we need Pbbub < Pcol u So, choose Pcol such that Pdbub < Pcol < Pbbub u If not, either choose utilities with a wider temperature range or relax the separation specs