Page 159 - Materials Chemistry, Second Edition

Comparison of Algal Biodiesel Production Pathways 147

medium could significantly reduce not only the need for chemical fertilizers and
their associated life cycle burdens but also the use of freshwater during algae
cultivation. Lardon et al. (2009) conducted an LCA study to analyze the potential
environmental impacts of biodiesel production from microalgae, and the outcome
of this study confirms the potential of microalgae as an energy source but high-
lights the imperative necessity of decreasing the energy and fertilizer consumption.
The present study is an effort to compare three harvesting technologies and two
oil extraction technologies involved in the production of algal biodiesel and
analyze the sustainability to use produced algal biodiesel in passenger cars in
comparison with fossil diesel.

2 Methodology

The study is conducted considering Danish conditions to cultivate algal biomass
and further processed for algal biodiesel production. In this study, six scenarios
were studied for Nannochloropsis sp. (Table 1).

2.1 Biodiesel Production Steps

The production process is divided into four steps, i.e., reactor design, biomass
cultivation, harvesting, and oil extraction and trans-esterification.

2.1.1 Bioreactor Design

The FPPBR is made up of LDPE sheet, and steel is considered for cultivation of
algal biomass as Ugwu et al. (2008) reviewed various algal cultivation systems and

Table 1 Description of different algal biodiesel production scenarios compared
Algal biodiesel production scenarios Abbreviation
Algal biodiesel production using Al flocculent AB1
and sCO 2 extraction and esterification method
Algal biodiesel production using Al flocculent AB2
and press and co-solvent oil extraction and esterification method
Algal biodiesel production using centrifugation AB3
and sCO 2 extraction and esterification method
Algal biodiesel production using centrifugation and press AB4
and co-solvent oil extraction and esterification method
Algal biodiesel production using lime flocculent AB5
and sCO 2 extraction and esterification method
Algal biodiesel production using lime flocculent AB6
and press and co-solvent oil extraction and esterification method