Integrated biodiesel plants: Options and perspectives

In this study, we investigate the upgrading of biodiesel plants into integrated biorefineries. Economic analysis and a life cycle assessment studies have been implemented for an integrated biodiesel biorefmery using its side-product (glycerol) to produce succinic acid (SA), a value-added chemical. Four process scenarios considering different uses of glycerol are simulated in Aspen Plus and Mat Lab and compared in this study. We examine simple utilisation methods of this side-product such as the disposal, distillation (80 %) and purification (95 %) of glycerol and we compare them in terms of economic and environmental impact with an integrated approach that produces SA via fermentation. For the latter case, we have incorporated into the overall process a batch fermenter to convert glycerol into succinate followed by a purification/recovery process to produce pure SA crystals. Furthermore, we have performed optimisation studies to compute the maximum profit and simultaneously to reduce the environmental impact. Profitability indicators are used to compare the developed biorefmery cases while environmental impact is calculated based on the CO₂ emissions for each scenario.