Thermodynamic and economic assessment of the production of light olefins from bioethanol

Abstract

The production of light olefins from bioethanol was evaluated in terms of thermodynamics and economics using Aspen Plus and Aspen Hysys as process simulators. The conceptual design of two different plants were proposed: one for ethylene and another for propylene and butenes production. A bioethanol sample containing characteristic compounds after biomass fermentation (e.g., ethanol, water, and aliphatics) was used as raw material in the plants, which could handle 10% of the Colombian bioethanol market. The plants delivered streams of 99mol% ethylene, 90mol% propylene, and a mixture of butenes. A class-V-order economic assessment of both optimized, heated-integrated plants was carried out giving total investments of 5.37 USD million for the ethylene plant (459 USD/ton ethylene-year) and 10.27 USD million for the propylene plant (2100 USD/ton of propylene and butenes-year). Traditional production routes from petroleum have reported comparative investment costs of 1300 USD/ton-year for ethylene and 1450 USD/ton-year for propylene. This initial feasibility analysis shows the potential of olefin production, mostly ethylene, from real fermented bioethanol, as an interesting approach to the biorefinery concept that could make their production more sustainable and economic.