Techno-economic analysis of Scenedesmus dimorphus microalgae biorefinery scenarios for biodiesel production and glycerol valorization

In this work five biorefinery scenarios are proposed for the production of five different target products. Two of these scenarios included biodiesel production from Scenedesmus dimorphus microalgae biomass and glycerol valorization through bioconversion into dihydroxyacetone (DHA) with the bacteria Gluconobacter oxydans. Experimental data of microalgae biomass composition were used as inputs to simulate reactive distillation column (RD) and continuously stirred tank reactor (CSTR) for microalgae oil transesterification stage. Optimum methanol/microalgae oil molar feed ratio, catalyst mass and reflux ratio were determined from simulated conditions with the Aspen Plus® V.10.0 Software. The biorefinery with the best economic performance integrated RD and glycerol valorization processes and achieved an internal rate of return (IRR) of 19.8%. The results showed that the combined use of reactive distillation (RD) with the biological oxidation of glycerol into DHA allows economically feasible biorefinery schemes using Scenedesmus dimorphus microalgae biomass as a feedstock.