Page 83 - Biofuels for a More Sustainable Future

Indicators for sustainability assessment 75

the biofuel industry, capable of contributing to make it less vulnerable to
market variations (IEA, 2014; Vaz, 2011).
Within this context we can highlight the proposals of integrated produc-
tion models, also referred to as biorefineries, which have been highlighted
as alternatives to improve interaction in the production of bioenergy, che-
micals, and food from the sustainable processing of biomass (Fatih Demirbas,
2009; Ghatak, 2011; Garcia-Nunez et al., 2016; Ali et al., 2015).

2 Technological aspects
2.1 Biofuels
The term biofuel refers to solid, liquid, or gaseous fuel that is predominantly
produced from renewable sources (biomass) (Fatih Demirbas, 2009). There
are different sources of biomass for biofuel production, such as oleaginous
plants (macau ´ba, sunflower, colza, dend^e, pinha ˜o-manso, algae, buriti), cereals
(maize,wheat,barley),agriculturalandforestryproducts,industrialanddomes-
tic organic residues, and animal fat and used frying oil (Hoekman, 2009).
According to Directive 2003/30/EC of the European Parliament, which
was transposed to Brazilian legislation by decree-law no. 62/2006, the fol-
lowing are considered biofuels:
• Biodiesel: methyl ester produced from vegetal or animal oils, which pre-
sents fuel properties for diesel engines. It is mainly obtained from oleag-
inous plants such as palm, dend^e, colza, soy, mamona, sunflower, and so
on, through a chemical transesterification process.
• Biomethanol: Methanol produced from biomass through gasification.
• Bioethanol: Ethanol produced from biomass or from the biodegradable
fraction of residues. It is produced from the fermentation of sugar, found
sugarcane, wheat, maize, potato, and so on.
• Biogas: Fuel gas obtained from biomass or the biodegradable fraction of
residues (agricultural or livestock, agroindustry and urban effluents) that
can be purified to reach the quality of natural gas. It is a result of the anaer-
obic biological degradation of the organic matter contained in the
residues.
• Dimethyl bioether: dimethyl bioether produced from biomass.
• Bio-ETBE (ethyl tertiary-butyl ether): ETBE produced from bioethanol. In
France, it is utilized as oxygenate additive to lead-free gasoline formulations.
• Bio-MTBE (methyl tertiary-butyl ether): fuel produced from biomethanol.
• Synthetic biofuels: Synthetic hydrocarbons or mixtures produced from
biomass.