Design and Economic Analysis of a Thermochemical Lignocellulosic Biomass-to-Butanol Process

A novel continuous lignocellulosic biomass-to-butanol process using a thermochemical route and a mixed-alcohol synthesis catalyst has been developed. The process was designed and modeled using Aspen Plus and consists of major process steps such as biomass drying; indirect steam gasification; syngas cleanup and conditioning; mixed-alcohol synthesis over a modified methanol catalyst; alcohol separation; and utilities including cooling water, steam, and power generation. A heat integration analysis was also carried out, resulting in an energy-sufficient process with no requirement for external hot utilities and net power production. A technoeconomic analysis was carried out using results of the Aspen Plus model, equipment cost estimates, and discounted cash flow analysis, with an assumption of nth-plant costs and financing resulting in a minimum butanol selling price (MBSP) of $0.83/L. Different plant and cost parameter scenarios were rigorously explored using a sensitivity analysis.