Techno-economic analysis of processes for biodiesel production with integrated co-production of higher added value products from glycerol

Abstract

A techno-economic analysis was conducted to compare 3 different processes for biodiesel production: (i) the conventional base-catalysed process (NaOH) (ii) a reactive coupling process to form glycerol carbonate (GLC) as a co-product in situ (iii) a reactive coupling to form solketal as a co-product in situ. The processes were simulated at rapeseed oil feed of 100,000 t/y. The capital investment and energy consumption of biodiesel production with associated GLC formation were found to be lower than that for the conventional process. The GLC process required $7.63 M capital investment and 2.2 MW per annum. The conventional process required $8.75 M capital investment and 5.4 MW per annum. Solketal production, however, was more capital-intensive, with $12.87 M capital investment and 25.8 MW. The 20-year net present values (NPVs) for the three biodiesel processes were: $65 M for the conventional alkali-biodiesel process, $128 M for solketal co-production and $631 M for GLC co-production. Clearly, the conversion of glycerol into higher added value species in situ can significantly increase the profitability of biodiesel production, particularly for glycerol carbonate formation.