Fast pyrolysis of raw and acid-leached sugarcane residues en route to producing chemicals and fuels: Economic and environmental assessments

Abstract

In this paper, we report on the economic and environmental issues associated with a pyrolysis plant for processing sugarcane residues. The analyses consider four scenarios: (i) raw sugarcane bagasse (SCB), (ii) raw sugarcane trash (SCT) and acid-leached (iii) sugarcane bagasse (L-SCB) and (iv) sugarcane trash (L-SCT). The systems were studied by integrating a comprehensive mathematical model and experimental data. The environmental impact assessment was performed using the Life Cycle Assessment (LCA) methodology, including agriculture and sugar industry stages into the system boundaries. The results demonstrate that the process economy heavily depends on the bio-oil composition, yield, feedstock cost, and leaching conditions. Bio-oil from L-SCT and L-SCB contained more than 30 wt%. levoglucosan, which made it a candidate to produce fermentable sugars or other valuable chemicals instead of being burnt in low-efficiency boilers. The unitary cost of bio-oil produced from L-SCT (0.89 USD/L) and L-SCB (0.75 USD/L) was below that obtained for raw biomass, even when the Total Investment Costs behaved differently. The environmental impacts, expressed in damage categories, associated with L-SCB and L-SCT, were nearly 86% higher than for SCB and SCT. The highest impact could be attributed to the citric acid (CA) production chain, biomass transport, and harvesting operations.