Editing Column still (section)

===Difference between pot still and column still===
Column stills behave like a series of single [[pot still]]s, formed in a long vertical tube. The tube is filled with either porous packing or bubble plates. The rising vapour, which is low in alcohol, starts to condense in the cooler, higher level of the column.  The temperature of each successively higher stage is slightly lower than the previous stage, so the vapour in equilibrium with the liquid at each stage is progressively more enriched with alcohol. Whereas a single pot still charged with wine might yield a vapour enriched to 40–50% alcohol, a column still can achieve a vapour alcohol content of 96%; an [[azeotrope|azeotropic]] mixture of alcohol and water. Further enrichment is only possible by absorbing the remaining water using other means, such as hydrophilic chemicals or [[azeotropic distillation]], or a column of 3A [[molecular sieve]]s, like 3A [[zeolite]].<ref>{{cite journal |last1=Burfield |first1=David R. |last2=Hefter |first2=Glenn T. |last3=Koh |first3=Donald S. P. |title=Desiccant efficiency in solvent and reagent drying 8. molecular sieve column drying of 95% ethanol: An application of hygrometry to the assay of solvent water content |journal=Journal of Chemical Technology and Biotechnology. Chemical Technology |volume=34 |issue=4 |pages=187–194 |language=en |doi=10.1002/jctb.5040340408 |date=1984|bibcode=1984JCTBC..34..187B }}</ref><ref>{{cite journal |last1=Simo |first1=Marian |last2=Sivashanmugam |first2=Siddharth |last3=Brown |first3=Christopher J. |last4=Hlavacek |first4=Vladimir |title=Adsorption/Desorption of Water and Ethanol on 3A Zeolite in Near-Adiabatic Fixed Bed |journal=Industrial & Engineering Chemistry Research |volume=48 |issue=20 |pages=9247–9260 |doi=10.1021/ie900446v |date=21 October 2009}}</ref>