Biobased propylene and acrylonitrile production in a sugarcane biorefinery: Identification of preferred production routes via techno-economic and environmental assessments

Four alternative, sugar-derived chemical intermediates were compared for the production of propylene and acrylonitrile in energy self-sufficient biorefineries, annexed to an existing sugarcane mill, to assess economic feasibility and environmental sustainability. Aspen Plus (R) process simulations considered ethanol and isopropanol produced from A-molasses as intermediates for propylene production, while propylene and 3-hydroxypropionic acid (3-HP) from A-molasses were compared for acrylonitrile production. The minimum selling prices (MSPs) for propylene-from-ethanol (3634 $/t), propylene-from-isopropanol (8151 $/t), acrylonitrile-from propylene (4698 $/t), and acrylonitrile-from-3-HP (5957 $/t) were 280 %, 752 %, 302 % and 409 % above the market prices of fossil-based equivalents. Nonetheless, the propylene biorefineries achieved up to 97 % reduction in greenhouse gas (GHG) emissions, whilst acrylonitrile biorefineries had up to 43 % reduction compared to fossil-based production processes. Based on process yields, energy demand and GHG emissions, ethanol was identified as the preferred intermediate route for all four biorefinery scenarios, while substantial price-premiums will be required for industrial production.