reflux ratio

[thubelihle]

Hi sir,
Was wondering how refluxing works. l fixed the bottoms flowrate hence ultimately fixing the distillate rate; l then increased my reflux rate. The distillate purity increased. My question is how is it possible to increase the reflux ratio without changing the distillate rate, since R = L/D. Thanks

[jasper]

By mass balance, if you fix the bottom flow rate, at feed feed rate, the top flow rate is also fixed.

If you want to change the reflux ratio without changing the bottom flow rate, specify the bottom flow rate.

In ChemSep, one specification is made at the top and the other at the bottom. Making both specifications at the bottom (e.g. reflux ratio and flow rate) I do not believe is supported.