457239 Intensification of Batch-Distillation Processes for Production of Alcoholic Beverages
Against the widely shared notion it is not possible to separate methanol by distillation using common batch distillation equipment, no matter if multi-stage columns or single-stage pot stills are used. Experimental investigations as well as dynamic simulations of single stage batch distillation with Aspen Hysys showed matching results. In fact methanol is distributed between foreshots, heart cut and tailings. Further the ratio of methanol to ethanol is increasing with cumulative distillation time. In addition high regulatory limits in the European Union for methanol concentrations in pomaceous fruit spirits of 1350 mg/100 ml pure ethanol compared to other spirits, e.g. wine brandies are often exceeded even though the high values are not set due to harmlessness to health but insufficient separation performance of standard batch distillation equipment. Hence the production of distilled pomaceous fruit spirits with less methanol content leads to the necessity of intensifying distillation processes with focus on new technical approaches.
The main goal of the current research is to improve the separation of methanol in the foreshots, using an extension of common lyne arms. For this purpose a pot still is equipped with an optional bypass which provides the possibility to route the vapor via an additional randomly packed lyne arm at the beginning of distillation to increase the separation efficiency. Further the bypass lyne arm enables enhancement of internal reflux, realized with a coaxial heat exchanger. In this manner methanol accumulates in the foreshots and may be separated from the heart cut sufficiently.