Techno-Economic and Environmental Assessments of 1,3-Propanediol and Xylooligosaccharide Production Annexed to a Typical Sugar Mill

Abstract

This study presents the economic and environmental assessment of biorefinery scenarios producing 1,3-propanediol (PDO) and xylooligosaccharides (XOS). Five biorefinery scenarios were simulated and assessed, annexed to an existing sugar mill with self-sufficient energy supply. PDO production was investigated in three scenarios, namely, PDO-D and PDO-I (direct and indirect fermentation processes of PDO production from A-molasses) and PDO-1G2G, which utilizes A-molasses and sugar cane bagasse/trash as the feedstock. Both XOS production from lignocelluloses (XOS-2G) and PDO production from A-molasses combined with lignocelluloses (PDO-XOS) are the other two studied scenarios. Internal rates of return (IRRs) of 11.1, 75.4, and 33.5% were obtained for PDO-I, PDO-D, and PDO-1G2G, respectively, for an assumed market price of USD3.38/kg. Scenario PDO-D was found to be energy efficient, while indirect production via glycerol as intermediate (PDO-I) was energy intensive due to the aerobic fermentation. A high market price of USD 25/kg for XOS led to a high IRR (87.9%) for XOS-2G. Consequently, the PDO-XOS scenario improved the energy efficiency of the biorefinery and resulted in a high probability of financial feasibility. Both PDO-D and PDO-XOS scenarios had low greenhouse gas emissions based on the Roundtable on Sustainable Biomaterials methodology, along with the excellent economic outlook.