Environmental Engineering Reference
In-Depth Information
Table 1.2
Comparison of petrorefinery and biorefinery in terms of feedstock, conversion
processes and products.
Petro-refinery
Biorefinery
Feedstock
Location
Rich deposits in some areas
Widely distributed
Density
High
Low
Availability
Continuous but finite
Seasonal but renewable
Chemical composition
Hydrocarbons; not
functionalised
Highly oxygenated and
functionalised
Conversion processes
Optimised over 100 years
Require further research
and technological
development
Products
On the market and to high
specification
Quality needs to be
standardised
1.5.3
Challenges and Opportunities
Biorefinery products (energy, chemicals and materials) will unavoidably have to
compete with existing and future petroleum-derived products. As seen in Table
1.2 (comparison of biorefinery and petrorefinery characteristics in terms of feed-
stock, process and products), the two types of refinery display major differences,
which translate into a number of challenges to and opportunities for the rapid and
widespread deployment of biorefineries.
1.5.3.1
Feedstock
Biorefinery feedstocks mainly consist of existing arable crops (e.g. cereals,
oilseeds), dedicated biomass crops (e.g. perennial lignocellulosic crops), biowaste
(e.g. agricultural and forestry residues, food and municipal wastes) and algae.
In contrast to fossil resources which are found in rich deposits ('mine mouth'
or 'well head'), biomass is widely distributed geographically (multiplicity of
'farm gate' or 'waste sources') [41, 48]. As such, the economic viability of
biorefineries largely depends on the availability of a reliable supply of appropriate
quality biomass at fair prices [49].
Biomass is clearly not an unlimited resource. Consequently, it is critical to
ensure that additional uses of biomass do not compromise the ability to produce
food and feed in sufficient quality and quantity [49]. Due to limited land availabil-
ity for biomass production for both food and non-food applications, the following
requirements are now widely recognised.
• We must increase the productivity and output of biomass from forest and
agricultural land through the development of high-yielding arable and perennial
crop varieties with greater value for industrial processing (e.g. higher oil or
starch content, more digestible lignocellulose) and increased tolerance to pests
and diseases under changing climatic conditions [50].
