Exergy analysis of canola-based biodiesel production in Belarus

Abstract

Exergy and life cycle assessment analysis are the key issues in evaluation of the potential of energy resources. However, the results of exergy analysis of biodiesel production greatly depend on the methodological approaches to exergy calculation and the peculiarities of local environment. In the current paper, detailed exergy analysis of the production of canola-based biodiesel was performed on the basis of classical model of the environment, considering all manufacturing stages from sowing of canola seeds to receiving of final biodiesel ready for sale. The typical spring canola (Brassica napus L.), cultivated on soddy–podzolic and loamy sandy soils at the usual weather conditions in the central part of Belarus, was used in the exergy analysis. The values of standard chemical exergies of canola biomass and its derivatives were determined from bomb combustion and heat capacity calorimetry data. It was found that total input of exergies during synthesis of methyl and ethyl esters makes 30.97 and 33.28GJha−1·yr−1, while output of chemical exergies with the target product and its concomitants (esters, glycerin and potassium dihydrogen phosphate) is equal to 27.82 and 29.19GJha−1·yr−1 for methyl and ethyl esters respectively. Obtained results testify to the high exergetical effectiveness of biodiesel production from canola, especially when major by-products and wastes are further processed into valuable matter.