(204b) Techno-Economic and Environmental Life Cycle Assessment (LCA) of Biodiesel Production Process from Waste Cooking Oil Via Supercritical Transesterification

This work describes the design of a non-catalytic biodiesel (Methyl Oleate) production process from waste cooking oil (Triolein) using supercritical methanol and propane. As compared to a conventional supercritical transesterification route, this process uses propane as a co-solvent to decrease the temperature – from 350°C to 280°C, reduce the pressure – from 400 bar to 128 bar and decreases the methanol to oil ratio - from 1:42 to 1:24 [1-3]. Different plant capacities ranging from 8000 ton/year to 125,000 ton/year were simulated in Aspen Plus software to conduct the techno-economic assessment for a plant situated in the Midwest region of the US. On the basis of mass and energy balance, process equipments such as multi-tubular reactor, evaporator, distillation column, etc. were sized and its subsequent economic analysis was performed in Aspen Plus.

Environmental Life cycle assessment of the process (LCA) was conducted using GREET and GaBi software tools to determine Greenhouse gas (GHG) emissions and evaluate the carbon footprint of the biodiesel production process. The technical, economic and environmental assessment results of this work were compared with conventional acid and base catalyzed transesterification processes to determine the economic and environmental sustainability of the supercritical biodiesel production process.

References:

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2. Cao W; Han H; Zhang J, Preparation of biodiesel from soybean oil using supercritical methanol and co-solvent, Fuel, 84, 347-51, 2005.
3. Farobie, O.; Matsumura, Y, State of the art of biodiesel production under supercritical conditions, Progress in Energy and Combustion Science, 63, 173-203, 2017.