Title: Sustainability assessment of microalgal biodiesel production processes: an exergetic analysis approach with Aspen Plus

Authors: Cynthia Ofari-Boateng; Teong Lee Keat; Lim JitKang

Addresses: School of Chemical Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang, Malaysia ' School of Chemical Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang, Malaysia ' School of Chemical Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang, Malaysia

Abstract: Biodiesel production growth rate keeps increasing every year with the hope of replacing fossil based liquid fuel which is near exhaustion. Energy efficiency methods coupled with environmental and economic sustainabilities would render biodiesel production attractive. Algal cultivation and oil extraction processes are found to be energy intensive hence exergy destructive. This study presents the thermodynamic feasibility of microalgal biodiesel production plant via exergy analysis. Mathematical modelling with Aspen Plus shows that the centrifuge for algae-medium separation recorded the highest exergy loss of 925 MJ representing 15% of the total exergy loss. 64% of the total exergy input into the whole plant is destroyed to attain the products (biodiesel and glycerin).

Keywords: exergy destruction; microalgae; biodiesel production; entropy generation; thermodynamic sustainability; exergy efficiency; mathematical modelling; sustainable development; algae; glycerin; alternative fuels; renewable energy.

DOI: 10.1504/IJEX.2012.047510

International Journal of Exergy, 2012 Vol.10 No.4, pp.400 - 416

Received: 29 Apr 2011
Accepted: 20 Oct 2011
Published online: 25 Jun 2012 *

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