SEPARATION OF ETHYL TERT-BUTYL ETHER-ETHANOL BY COMBINED PERVAPORATION AND DISTILLATION

A cellulose derivative membrane (30 wt.% cellulose acetate butyrate (C AB) combined with 70 wt.% cellulose acetate propionate (CAP)) was prep ared, and its properties were evaluated by the pervaporation separatio n of mixtures of ethyl tert-butyl ether (ETBE) and ethanol. The experi mental results showed that the selectivity and permeability of the mem brane were dependent on the blend composition, the processed feed and the experimental temperature. With respect to the temperature, the flu xes obeyed the Arrhenius equation. On the basis of these results, a se paration process for the production of ETBE was developed by combining pervaporation and distillation. The distillation column was designed with the software ASPEN PLUS, and the liquid-vapour equilibria were pr edicted by the UNIFAC method. The area of the membrane was calculated according to the production capacity. It may be concluded that the com bined process for the separation of mixtures of ETBE and ethanol is si mple with high recovery of the ETBE product. (C) 1997 Elsevier Science S.A.