BIOREFINERIES: INTEGRATION OF DIFFERENT TECHNOLOGIES - Biomass as a Sustainable Energy Source for the Future - page 472

biorefinery is an
overall concept of a promising plant where biomass feedstocks are converted and
extracted into a spectrum of valuable products

The US Department of Energy summarizes its unique features as: “

(tinyurl.com/kzhn5ej). The National
Non-Food Crops Centre in the United Kingdom uses a broad definition:

”

A biorefinery
is a manufacturing site involved in the refining of biomass material to yield purified
materials and molecules. This conversion can be achieved using biological or
thermochemical processing or a mixture of both. Downstream manufacturing sites
processing materials/molecules from biomass are often termed secondary biorefi-
neries

“

(NNFCC, 2007). In the definitions, often two aspects are not considered to
their full extent: food and feed coproduction and the self-supply of heat and electricity
of the refinery. IEA has dedicated a separate task (nr. 42) since early 2007 on bio-
refineries and has defined this concept of biomass processing clearly, emphasizing
the driving force from a broader context of sustainable development as follows
(Jungmeier et al., 2013):

”

Biorefining is the sustainable processing of biomass into
a spectrum of marketable bio-based products (food/feed ingredients, chemicals, mate-
rials) and bioenergy (biofuels, power and/or heat).

“

In biorefinery development,
different stages can be discriminated, which can be ranked into three generations
as has been worked out by Kamm and Kamm (2004):

”

Generation I biorefineries are characterized by the lowest flexibility because
feedstock type and products as well as resulting by-products are fixed. An example
is the dry-milling ethanol plant using grain as feedstock.
Generation II biorefineries are more flexible in the end products, for instance, a
wet-milling ethanol production plant can produce different products depending
on demand, which may include ethanol, starch, high-concentration fructose syrups,
oils, and animal feed.
Generation III biorefineries are the most flexible, as these can process a multitude
of biomass feedstocks into variable end products. Given the situation that often
a single type of biomass feedstock s availability within a reasonable distance

might not be sufficient to operate a plant at full capacity during the entire year, this
flexibility will become more and more necessary (Zinoviev et al., 2010).

'

A typical oil-based refinery is depicted in Figure 15.2 (Moulijn et al., 2001). Awide
range of products is generated from such a complex in all aggregation states: from
gaseous fuels (e.g., refinery fuel gas and intermediate synthesis gas/hydrogen), via
liquid products (liquefied petroleum gas (LPG), liquid transportation fuels, solvents,
lubrication oil, and greases), to solid coke.
Many processes have been developed for conversion of oil to intermediate and end
products. Some add hydrogen (hydrotreating, hydrocracking), and some remove
carbon (flexicoker) to improve the H/C ratio of the desired fuel product. Catalysts play
a key role in many processes. An example is the well-developed fluid catalytic crack-
ing unit in which heavy oil is cracked to produce gasoline using a catalyst in a riser
(vertical transport) reactor. The mostly linear alkanes produced need to be catalytically