Abstract

Two subsequent separation processes are required to produce absolute ethanol (at least purity of 99.5% v/v),namely the distillation and adsorption processes. Thus, it is important to find the optimum operation conditionfor those following processes. The aims of the present study are to optimize the feed plate of distillation and thetemperature of feed adsorbent. This study is conducted using a continuous sieve tray distillation system with thenumber of 16 trays, the length-diameter ratio of 80.64, the reflux ratio of 3.5, and the feed with ethanol contentof 10 % v/v ethanol, which is produced via the fermentation process of molasses. To conduct the first aim of thisstudy, the feed enters the distillation column with several of variable feed plate, i.e. 12, 13, 14, and 15. This feedplate location is calculated from the top of the column. On the other hand, the second aim of this study, isconducted using the subsequent combination of distillation and adsorbent columns, where the distillate (purity ofethanol around 95% v/v) from the distillation column is then flowed into the adsorbent column with various feedadsorbent temperature, i.e. 80 °C, 90 °C, 100 °C, and 110 °C, to be purified as an absolute ethanol. Here theadsorbent column is designed as a fix bed adsorption column with a molecular sieve of 3A (zeolite) is used as anadsorbent for that purification process. Our results showed that the optimum feed plate is 14, because at thisplate the ethanol distillate has the highest content among those various variables. Meanwhile, the optimumtemperature of feed adsorbent is 90° C, which requires the least energy for the distillation - adsorption process,i.e. at 18691 kJ/kg absolute ethanol. This primary study is expected to be an alternative way to optimize theoperating condition of the sieve tray distillation-molecular sieve adsorption system by means of acquiring aminimum energy involving in the process to achieve the highest purity of ethanol.

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