Environmental Engineering Reference
In-Depth Information
the form of a dry solid or a liquid such as pyrolysis oil) which can be stored,
allowing the biorefinery to run continuously all year long [58]. Such an approach
will yield the added benefits of reducing the environmental impact of transporta-
tion [55], allowing farmers to gain a greater share of the total added value of the
supply chain.
1.5.3.2
Conversion Processes
The major impediment to biomass use is the development of economically viable
methods (physical, chemical, thermochemical and biochemical) to separate,
refine and transform it into energy, chemicals and materials [29, 59]. Biorefining
technologies (most of which require further research and technological develop-
ment) have to compete with well-developed and very efficient processes which
have been continuously improved by petrorefineries over the last 100 years; the
latter demonstrate a very high degree of technical and cost optimisation. Large
investments will therefore be required from the public and private sector to bring
these technologies to maturity through research, development, demonstration and
deployment [60, 61]. The EU and a consortium of bio-based industries have
recently committed to jointly invest over €2.8 billion in research and innovation
between 2014 and 2020 [62].
Priorities for research and development include the following topics.
•
Pre-processing
: there is currently no effective way to separate the major compo-
nents of biomass (i.e. cellulose, hemicellulose and lignin). More sophisticated
and milder pre-treatment methods therefore need to be developed [63].
•
Chemical catalysis and biochemical processes
: in contrast to fossil resources,
biomass feedstocks are composed of highly oxygenated and/or highly function-
alised chemicals (see Table 1.3). This means that we must apply significantly
different chemistries (e.g. reduction instead of oxidation) to convert them into
the valuable chemical products our society is built on and, in particular, develop
new catalysts that are able to work in aqueous media [46, 64]. These include
new biocatalysts (microorganisms and enzymes) being developed through the
novel field of synthetic biology.
•
Thermochemical processes
: research should focus on scaling-up and integrating
these processes into existing production units as well as end-product quality
improvement [50].
Table 1.3
General chemical composition of selected biomass components and petroleum.
Reproduced with permission from [65]. Copyright © 2008, John Wiley & Sons, Ltd.
Cellulose/starch
[C
6
(H
2
O)
5
]
n
Gasoline
C
6
H
14
-C
12
H
26
Hemicellulose
[C
5
(H
2
O)
4
]
n
Diesel
C
10
H
22
-C
15
H
32
Lignin
[C
10
H
12
O
4
]
n
