Comparative techno-economic assessment and environmental impacts of rice husk-to-fuel conversion technologies

This study compared techno-economic performances and environmental impacts of different technologies for rice husk-to-fuel biorefinery - hydrothermal carbonization with pelletization (HTC), pyrolysis (PYR) and anaerobic co-digestion (AD) process - and benchmarked against a conventional direct combustion (DC) for combined heat and power. Economic analysis through techno-economic (TE) model showed HTC with the greatest potentials compared to other processes due to its high-solid operating capacity and could be cost-competitive against the DC technology. Analysis results also highlighted a need for improvement of PYR and AD process in term of the increase of solid loading operation and the exploration of process wastes for better economic benefits and cost competitiveness. Based on life-cycle analysis (LCA) model, HTC yielded the lowest carbon and water footprints from amongst the analyzed options. Nevertheless, all three options had lower GHG emissions and water utilizations than DC process, indicating better environmentally advantageous of these processes. The LCA of three conversion technologies showed better environmental performances mainly lower global warming potential, lower photochemical oxidation potential and lower acidification potential than the DC reference system. The results obtained from this work could be exploited by decision makers for selecting appropriated biomass-to-fuel process based on environmental and economic performances.