Green Chemistry Principles - Process Intensification for Green Chemistry - page 46

The source of renewable feedstocks is critical for sustainable development. While there
are vast quantities of rice in China, cassava in Africa and corn in the USA, their conversion
to chemicals or fuel would be inappropriate as it would drive up food prices and ultimately
lead to famine and hunger within these countries. Therefore, biomass wastes such as corn
stover [43], wood [44], bagasse [45], wheat straw [46], other food industry wastes and
biomasses that are independent of food production, such as seaweed [47], are more
appropriate for biorefining. The quantities of food supply-chain waste alone are staggering
(over 1 billion MT per year) and represent a carbon equivalent comparable to the total
amount of carbon used in organic chemicals, currently largely provided from non-
renewable petroleum. There is a wide variety of biomass available to us for use as a
renewable feedstock for fuels and chemicals - this is both an issue and an opportunity.
The dispersed distribution, seasonality and large number of different biomass types
available mean conversion technologies have to be flexible and universally applicable
for the conversion of these materials. On the other hand, the wide range of biomasses, the
wide growing range and the seasonality of different biomasses also mean that energy and
chemical security is less of a problem than with fossil fuels. Each and every area of the
globe should be able to grow biomass for local use and be able to survive in the event of
crop failure.
The biorefinery concept that has emerged (see Figure 2.7) is analogous to today's
petroleum refineries: integrated facilities for the conversion of biomass into multiple value-
added products, including energy, chemicals and materials [48,49].
Improvements are needed to create flexible, zero-waste networks, applicable to a
variety of low-value local feedstocks. Biorefineries will then be able to challenge the
current status quo and develop novel interconnecting webs of products capable of

Figure 2.7 Biorefinery concept.