Computer-aided framework for the design of entrainer for palm process residue recovery

Abstract

Oleochemical industry produced substantial palm process residue during hydrogenation process of fatty acid/methyl ester, containing medium- to long-chain fatty alcohols and alkanes with overlapping boiling points. Recovering fatty alcohols for sale and utilizing alkanes for jet fuel, lubricants, and gasoline is beneficial. However, separating them through conventional distillation (CD) is challenging and expensive due to the difficulty in achieving the necessary temperature differentials for phase changes, especially with high reflux ratio required. To address this challenge, extractive distillation (ED) with an entrainer, designed through computer-aided molecular design (CAMD), was employed. However, implementing ED with a high boiling entrainer is challenging due to the high boiling point of the target components. Therefore, the design of the entrainer focused on the relative volatilities (α) of involved components and associated utility costs. Then, Aspen HYSYS was employed to evaluate the performance of the designed entrainer through product purity and economic analysis. For the separation of C10OH and n-C12, octane and dimethylcyclohexane were generated as entrainers. Dimethylcyclohexane entrainer demonstrated superior separation and generated higher profit than octane entrainer. For the separation of C12OH and n-C14, n-C15 was generated as entrainer to replace the infeasible CD. Therefore, the study concluded that ED with tailored entrainer can effectively replace CD for separating fatty alcohols from alkanes, demonstrating significant industrial feasibility.