Energy, Exergy, Economic, and Environmental (4E) analysis of circular biodiesel and glycerol upcycling

The development of sustainable bioenergy technologies is positioned as a fundamental pillar for the development of local economies and a promising solution for the energy sector decarbonization. In the aim to contribute to these efforts, the present research considers a comprehensive process evaluation for a sustainable fuel production. Furthermore, chicken fat waste is considered as feedstock for the production of biodiesel with two glycerol valorization roots: The first configuration suggests a glycerol-biodiesel blend combustion for energy supply to the transesterification process, while the second process propose hydrogen production through in-site glycerol reforming. These two configurations were simulated using Aspen Plus software. Then, in order to select the optimal process configuration, multiple decision criteria including fundamental process engineering assessment tools such as energetic, exergetic, environmental and economic assessments were performed.Results revealed that hydrogen case presents a better thermal efficiency with 79.34% compared to 70.33% in the heat integrated configuration. The exergetic efficiency of the two configurations are 76% and 65% in hydrogen case and heat integrated case respectively. Environmental results indicate that 1 GJ of energy produced from chicken fat generates approximately 13.63 kg CO2-eq via hydrogen case and 26.75 kg CO2-eq by Heat integrated cases. From an economic point of view the hydrogen case is found more profitable.