Biochemical production of short-chain alcohols from glycerol: process simulation and economic evaluation

Abstract

Short-chain alcohols, such as ethanol, propanol and butanol, are examples of chemicals that can be obtained from glycerol. Ethanol is already a consolidated biofuel, and propanol and butanol are potential fuels and fuel additives, among other applications. Biochemical routes using modified Escherichia coli strains as biocatalysts are herein investigated as routes to produce these alcohols from glycerol. Hence, this work aims to perform a preliminary technical-economic assessment of the production processes of ethanol, propanol and butanol from glycerol, using Aspen Plus® v12. The required investment and production costs of the plants were estimated in order to evaluate the economic viability of the processes. Long batch times (40–120 hours) and the need for high glycerol dilutions (10–40 g L⁻¹) are the bottlenecks that must be overcome to make the studied processes attainable on an industrial scale. Moreover, propanol production from glycerol seems to be more likely to become an industrial reality than ethanol or butanol production, as the required process modifications (74% reduction in the reaction time) are more achievable than in the case of ethanol (99.7% reduction) and butanol (99.9% reduction).