The Effect of Column Height, Packing Materials and Azeotrope Separation on thePurity of Ethanol Sourced from Ogogoro (Local Gin)

摘要

Locally brewed Ogogoro, a mixture of ethanol and water in the ratio of 28:72 by volume was separatedinto its constituents by means of fractional distillation. The mixture of 95.5% ethanol and 4.5% water(percentage by volume) formed an azeotrope with a boiling point of 78.2EC and thus could not be furtherpurified by distillation. The ethanol/water mixture after distilling to the azeotrope was shaken with calcium oxideto form the non-volatile compound, calcium hydroxide which altered the stability of the azeotrope and hencefurther separation of the constituents of the mixture. Nearly all of the calcium hydroxide was removed byfiltration and the filtrate was redistilled to obtain higher puzrity ethanol relative to the azeotrope. The percentagepurities of the ethanol were 96.5, 97% with the highest purity being 97.5%. The mass of calcium oxide used wasvaried at a constant time of 1 h and the effect on the percentage of ethanol achieved were recorded as 95.5, 97.7,97, 96.5 and 96.5% from the initial percentages 95, 95, 95.5, 95.5 and 95.5% ethanol, respectively. By comparingmasses, 10 g of calcium oxide gave the highest percentage purity of ethanol after distillation which was 97.5%.Also, in order to determine the effect of time on product purity, the duration for drying the ethanol/water mixturewith constant mass of 10 g calcium oxide was varied from 1-5 h. It was observed that increase in drying time forthe ethanol/water mixture after 1 h did not lead to increase in the purity of ethanol distilled. The effects ofincrease in height of column as well as number of random packing was investigated and found to increase theefficiency of the distillation process. Using the double fractionating column of height 77 cm with 145 randomglass packing improved the purity of the ethanol from 40-2% as compared with 86% which was the percentagepurity obtained when a single fractionating column of height 46 cm with 92 random glass packing was used.