Economics of alternative sugar cane milling options

Abstract

Cane processing energy consumption (per unit mass processed) varies between sugar mills. Although lower energy consumptions appear to indicate better performance, closer examination of the sugar extraction process reveals that more efficient extraction may increase sugar revenue sufficiently to offset higher investment and specific energy consumptions. The present analysis relates to proposed modifications in the milling process in Agroval, an old sugarcane factory. Cane processing energy consumption and sugar extraction efficiency for the current process that extracts 92.1% of the sugar, are compared to a hypothetical process similar to that in Japungu, a modern fuel alcohol distillery. Since the fermentation broth must be dilute, distilleries can use more soak water to increase juice extraction during crushing so bagasse humidity and sugar dilution in the cane juice are higher. Though more energy is expended to process cane the proposed process extracts 95.7% of the sugar content. An analysis of the substitution of the process in Agroval, based on measured and estimated data, suggests that if the evaporator steam consumption does not rise appreciably, the net revenue increases significantly. Further measurement and analysis could determine the expected improvement more accurately.