Page 20 - Biofuels for a More Sustainable Future

Biofuels technologies: An overview of feedstocks, processes, and technologies 13

any refinement. The process does not produce biomass either, thus making
the technology easier to apply in practice. Although the company was dis-
continued its operation in August 2017 due to difficulties with raising addi-
tional funds for future developments, the suggested innovation based on
helioculture presents an attractive technological attempt. The company
claimed to be able to produce more than 20,000gal of fuel per acre per year
3
2
(19,000m /km ). The economic estimates by Joule Unlimited claimed its
3
product to be cost competitive with crude oil at $50 a barrel ($310/m )
(St. John, 2010).
Moreover, nanotechnology has also been considered as a technological
solution to alleviate challenges related to algal biomass growth and cultiva-
tion (Sekoai et al., 2019; Gavrilescu and Chisti, 2005), mainly high costs of
algae harvesting and production as well as energy-intensive lipid extraction
(Pattarkine and Pattarkine, 2012). A new form of “nanofarming” technol-
ogy is currently in the pilot stage and could find wide commercial applica-
tion. It facilitates oil extraction from algae even more efficiently as it relies on
a process of “milking algae,” thus using biomass continually (up to 70days)
rather than destroying it as is the common case with conventional material
science processes (Vinayak et al., 2015; Chaudry et al., 2016;
Ziolkowska, 2018).

3 Biofuels processes

From the technological perspective, four main processes can be distin-
guished for biofuels production:
(a) Mechanical processes involving traditional processing of wood materials
through mechanical treatment, for example, chipping or grinding,
and potentially the following densification of the material by pelletizing
the biomass.
(b) Thermochemical processes converting biomass into energy through com-
bustion, followed by pyrolysis. This process is more efficient than
mechanical processes due to greater energy density as well as chemical
and physical fuel properties being more similar to fossil fuels. Another
possible process is gasification generating syngas for the production of
different liquid biofuels, through the Fischer-Tropsch (FT) process.
(c) Chemical processes are used mainly for the production of transportation
fuels, such as biodiesel and cellulosic ethanol.