Anaerobic co-digestion of residues in 1G2G sugarcane biorefineries for enhanced electricity and biomethane production

The energy potential of residue-derived biogas via electricity and biomethane production was assessed in an integrated 1G2G sugarcane biorefinery concept. The mono-digestion of 1G-vinasse (1G-VN) was compared with different co-digestion systems, namely, 1G-VN + filter cake (FC) + deacetylation liquor (DL) in the season and FC + DL in the off-season. Gross energy output values and the resulting sugarcane use efficiency were also assessed in different biorefinery schemes. Electricity production from 1G to VN (5.0 MW) could be increased by over 400% through its co-digestion with FC and DL (22.3 MW). Alternatively, biomethane could fully supply the diesel-powered fleet (1.8 × 10⁶ Nm³ month^-1) of a sugarcane plant processing 10 million tons of sugarcane per harvest, and the surplus biogas could flexibly provide 36 MW of extra electricity. Biomethane could enhance the energy output of 1G2G sugarcane biorefineries by 15%. However, 2G processes still require marked improvements to maximize energy production from sugarcane.