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Indicators for sustainability assessment 77

An important aspect in the development of biorefineries is finding the
route that provides the best economic and energy gains, with the least social
and environmental associated impacts (i.e., the most sustainable route)
(Ishiyama and Paterson, 2011).
Knowledge on the conversion process enables the optimization of the
available processes and obtainment of more sustainable products in compar-
ison with those produced from conventional resources. Fig. 4.2 depicts all the
factors to be considered in the implementation of an optimized biorefinery.
The following indicators must be considered when determining the best
option for the biorefinery:
• Raw material utilized: characteristics, resources employed in its production,
productivity, environmental impacts, among others.
• Energy conversion technologies utilized: efficiency of processes, economic
costs, development stage, and so on.
• Products: Energy, food, fuels, chemical products, and so on.
Evaluation of the current stage of development of conversion technologies is
very important. Some conversion mechanisms are already consolidated at a

Feedstock Conversion technology Final products

A

X
1
5 8
B
2
Y
6 9
3
C
7 10
4 Z

D

Fig. 4.2 Relevant factors for optimizing of biorefineries. (Modified from Murillo-Alvarado,
P.E., Ponce-Ortega, J.M., Serna-González, M., El-Halwagi, M.M., 2013. Optimization of
pathways for biorefineries involving the selection of feedstocks, products, and processing
steps. Ind. Eng. Chem. Res. 52, 5177–5190.)