Techno-Economic Analysis of Biodiesel Production from Microbial Oil Using Cardoon Stalks as Carbon Source

Today one of the most interesting ways to produce biodiesel is based on the use of oleaginous microorganisms, which can accumulate microbial oil with a composition similar to vegetable oils. In this paper, we present a thermo-chemical numerical model of the yeast biodiesel production process, considering cardoon stalks as raw material. The simulation is performed subdividing the process into the following sections: steam explosion pre-treatment, enzymatic hydrolysis, lipid production, lipid extraction, and alkali-catalyzed transesterification. Numerical results show that 406.4 t of biodiesel can be produced starting from 10,000 t of lignocellulosic biomass. An economic analysis indicates a biodiesel production cost of 12.8 USD/kg, thus suggesting the need to increase the capacity plant and the lipid yield to make the project economically attractive. In this regard, a sensitivity analysis is also performed considering an ideal lipid yield of 22% and 100,000 t of lignocellulosic biomass. The biodiesel production costs related to these new scenarios are 7.88 and 5.91 USD/kg, respectively. The large capacity plant combined with a great lipid yield in the fermentation stage shows a biodiesel production cost of 3.63 USD/kg making the product competitive on the current market of biofuels by microbial oil.