Comparative techno-economics of 2,3-butanediol, polyhydroxybutyrate and citric acid production in a biorefinery using 1G and 1G2G sugarcane-based feedstocks
Mirelle René Gouws, Catharine Elizabeth Bosman, Eunice Sefakor Dogbe, Johann F. Görgens
Abstract
Product diversification in sugar mills has become imperative to ensure the sustainability of the global sugar industry. Here, the economic feasibility of six biorefinery scenarios, each annexed to a sugarcane mill, was evaluated through Aspen Plus® simulations and techno-economic analysis. Production of 2,3-butanediol, polyhydroxybutyrate and citric acid was compared using 1st-generation feedstock (A-molasses) or 1st- and 2nd-generation feedstock (A-molasses, sugarcane bagasse and brown leaves). The minimum selling prices of 2,3-butanediol (1st-generation – 1.91 $/kg; 1st-generation-2nd-generation – 2.28 $/kg) and polyhydroxybutyrate (1st-generation – 6.81 $/kg; 1st-generation-2nd-generation – 7.23 $/kg) were below their market prices (2.63 $/kg and 7.60 $/kg, respectively) deeming such biorefineries profitable. Both citric acid scenarios were unprofitable with minimum selling prices (1st-generation – 2.44 $/kg; 1st-generation-2nd-generation – 2.60 $/kg) above the market price (0.80 $/kg). Compared to alternative sugarcane biorefinery products, 2,3-butanediol and polyhydroxybutyrate are some of the few products showing attractive economics under current conditions.