Page 173 - Materials Chemistry, Second Edition

Comparison of Algal Biodiesel Production Pathways 161

Fig. 10 Percentage difference of single score impact per impact category for EURO 5 passenger
car running on algal biodiesel produced in different scenarios in reference to fossil diesel

scenarios with press and co-solvent oil extraction than sCO 2 oil extraction, while
impacts on ecosystem quality, and resources were higher in sCO 2 oil extraction
process in comparison with press and co-solvent oil extraction scenarios. The
higher impacts on human health in press and co-solvent oil extraction scenarios
might be due to the use of solvent in oil extraction. Impacts of different harvesting
techniques showed similar trend on human health and resources, maximum with
aluminum flocculation, followed by centrifugation and lime flocculation. Centri-
fugation harvesting technique provides higher impact on ecosystem quality, while
aluminum and lime flocculation techniques provide about similar impacts
(Fig. 11).
The sensitivity analysis was conducted by increasing the oil content in algal
biomass from 29.6 to 60 %, and results of sensitivity analysis are presented in
Tables 3, 4, 5, and 6. The increase in oil content reduces the impacts on various
categories and decreases the savings of global warming potential of algal biodiesel
(Table 3). The savings on climate change decreased to 257 from 531 %. This
might be due to less biomass necessitates less uptake of CO 2 , higher consumption