Revitalizing the sugarcane industry by adding value to A‐molasses in biorefineries

Abstract

AbstractThe downward trend of global sugar market prices, as well as rising energy prices, threaten the survival of the South African sugar industry. Operating a single‐stage sugar crystallization process, which produces less crystalline sugar along with sucrose‐rich A‐molasses as a by‐product, to which value can be added in an integrated biorefinery, could be a viable solution for the industry. It would offer a diversification option as opposed to the current three‐stage crystallization process designed to achieve maximum sugar recovery. This study presents a rigorous Aspen Plus simulation development and economic assessment of different biorefinery scenarios producing succinic acid (SA) and short‐chain fructooligosaccharides (scFOS) from A‐molasses at target market sizes of 440 kt/year and 160 kt/year, respectively, considering the production capacity and market price interplays. In all, seven scenarios of single‐ or multi‐product(s) biorefinery annexed to an existing sugar mill were developed and assessed. Due to the integration benefits, all scenarios studied delivered an internal rate of return (IRR) between 24.1–61.1%, significantly above the required discount rate of 9.7%. In particular, co‐production of SA and scFOS syrup at production rates 40.5 kt/year and 13.5 kt/year from 70% and 30% of the A‐molasses, respectively resulted in the IRR of 56.1% and was considered the most attractive scenario based on the diverse bio‐production, economic performance and easy market entry of the products determined by low minimum selling prices. The proposed integration can lead to the sustainable operation of existing sugar mills by utilizing resources more efficiently, employment of product diversification and job creation. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd