Integration of a small biofuel refinery in a rural context

In this work three scenarios of biomass production, conversion and utilization of different biofuels (sunflower crude oil, sunflower refined oil and sunflower methyl-ester) in a rural context are compared. The analysis is referred to the district of Pisa, in Italy. Technical feasibility was analysed by comparing process schemes and safety issues, while environmental impacts were studied by applying the methodology of life cycle assessment. Scenarios involving upgrading of crude sunflower oil (refined oil and biodiesel) require complex plants and the management of dangerous materials, and they produce considerable amounts of wastewater. These scenarios need larger plant size, more complex organization (farm cooperatives) and higher costs than the simple mechanical operations associated with crude oil production. On the other hand the use of low-quality fuels in internal combustion engines can lead to short engine lifetime and high pollutant emissions. The life cycle analysis shows that the biofuel upgrading processes (refining and transesterification) and oil transport have a low influence on the environmental impact, compared to seed cultivation, which is the most impacting step. However fuel upgrading allows a significant reduction in polluting emission during combustion; as a consequence biodiesel results the most sustainable biofuel.