Parametric investigation of fixed-tray, semi-continuous distillation column for ethanol separation from water

Abstract

This work was aimed to evaluate the parameters affecting the separation of model fermentation broth (7 mole% ethanol) using 10-tray, semi-continuous distillation column. Ethanol compositions in distillate and bottoms were determined at different reflux ratios and feed locations. Results show that the distillation of lower ethanol concentration is better carried out at higher reflux ratio with feed charged at the middle or bottom tray for good overall tray efficiency. The distillation unit is able to purify the feed to 78 mole% ethanol in distillate. Through trial-and-error stepping off, about 81 mole% was predicted as optimum ethanol purity at reflux ratio of 2.33, while a lower reflux ratio of 1.44 was estimated for 78 mole%. Fixed-tray, semi-continuous distillation is a suitable option to concentrate fermentation broth with sufficient ethanol purity.