CHEMICAL ENGINEERING TRANSACTIONS VOL. 29, 2012 A publication of The Italian Association of Chemical Engineering Online at: www.aidic.it/cet Guest Editors: Petar Sabev Varbanov, Hon Loong Lam, Jiří Jaromír Klemeš Copyright © 2012, AIDIC Servizi S.r.l., ISBN 978-88-95608-20-4; ISSN 1974-9791 DOI: 10.3303/CET1229134 Please cite this article as: Iancu P., Plesu V. and Velea S., (2012), Flue gas CO2 capture by microalgae in photobioreactor: a sustainable technology, Chemical Engineering Transactions, 29, 799-804 799 Flue Gas CO 2 Capture by Microalgae in Photobioreactor: a Sustainable Technology Petrica Iancu* a , Valentin Pleşu a , Sanda Velea b a Centre for Technology Transfer for the Process Industries, Department of Chemical Engineering, University POLITEHNICA of Bucharest, 1, Gh. POLIZU Street, tRO-011061 Bucharest, România b The National Institute for Research & Development in Chemistry and Petrochemistry, 202 Splaiul Independentei, Sector 6, RO-060021, Bucharest, România pres2012@chim.upb.ro This paper addresses the development of pilot scale sustainable technology for microalgae capture of CO2 from power plant flue gas in alkaline solutions to produce biodiesel from algal oil. A combination of computer tools for process simulation, economic evaluation, and environmental impact allow sustainable process assessment. Laboratory scale experiments for growth and culture for algae in laboratory photobioreactor are considered. Based on them, CO2 biocapture, biomass harvesting and algal oil extraction are evaluated. Process flowsheet for pilot scale CO2 biocapture from flue gas, growth and separation of biomass, as well as algal oil separation is implemented in SuperProDesigner ® v8.5 simulator. Solvent is recovered by distillation and recycled. Experiment information allows to setup flowsheet, unit operations and unit procedures mass balance. As semi-batch process is considered, feedstock quantity/ flowrate and processing times are calculated. Process simulation predicts for ~ 1,400 kg CO2/y biocapture with ~45 % yield, ~200 kg algal oil/y is produced. Technology sustainability is evaluated by economic and environmental performance. Process economics is evaluated with SuperProDesigner ® and environmental impact with WAR software tool. 1. Introduction Capture and storage of CO2 from large local sources, such as fossil fuel power plants, represents an important measure to reduce global warming (Klemeš et al., 2007, Klemeš et al., 2010). Algae are suggested as good candidates for CO2 capture. One alternative is to produce biodiesel, due to their higher photosynthetic efficiency, higher biomass production, and faster, growth compared to other energy crops. Microalgae need only sunlight, water, CO2, and minerals for their growth in photobioreactors. Most of the research on algal biofuel has come from the analysis of laboratory-based small scale and pilot scale cultures, presenting that biodiesel production is both economically and environmentally sustainable. (Molina et al., 2003; Stephens et al., 2010).. However, there are some sceptical views (Chen et al., 2011; Lam and Lee, 2012). Overviews for biodiesel production by microalgae, include various cultivation modes (Huang et al., 2010; Demirbas, 2011). Different approaches for investigation of process sustainability were identified in literature. Pfromm et al., 2011 propose an engineering mass balance/unit operation approach to investigate bioprocess from techonological point of view. Life Cycle Analysis approach is used for sustainability evaluation taking into account environmental, economical and safety aspects (Dinh et al., 2009). Other integrated algorithm for development of sustainable bioprocesses is proposed by Heinzle (2006), as presented in