Techno-economic assessment of one-stage furfural and cellulosic ethanol co-production from sugarcane bagasse and harvest residues feedstock mixture

Abstract

Co-production of furfural and ethanol from mixture of sugarcane bagasse and harvest residues in a biorefinery annexed to a sugar mill was investigated. The study considered energy self-sufficient scenarios producing furfural-only (scenario 1), ethanol-only (scenario 2) and integrated furfural-ethanol co-production at a range of operating conditions (scenarios 3–7). Scenario 1 was based on the industrial furfural process conditions (180 °C), which was replaced with steam explosion pretreatment at 205 °C in the ethanol-only Scenario 2. Furfural process conditions of Scenarios 3,4 and 6 were autocatalytic at 170 °C, 200 °C and 185 °C, respectively, while the furfural conditions with 0.5 wt% H2SO4 at 170 °C and 185 °C were applied for Scenarios 5 and 7, respectively. All investigated scenarios were simulated in Aspen Plus® V8.8, with economic viability expressed by internal rate of return (IRR). The integrated furfural and ethanol biorefinery (Scenario 5) was more profitable than the ethanol-only production (scenario 2) as indicated by 12.78 % and 10.18 % IRR, respectively. However, furfural-only biorefinery was the most profitable with IRR of 12.92 % as it was associated with lower total capital investments (272 million US$) and bypass (51 %). Although total capital investments (305 million US$) and feed bypass (58 %) were higher, the integrated furfural and ethanol biorefinery (Scenario 5) was more economically viable without electricity sales (IRR = 10.30 %) due to higher furfural yield (69 %). The economic benefits of furfural and ethanol co-production were limited by the process energy demands, which could only be supplied by feedstock available in the integrated biorefinery.