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The EU has funded a number of research
projects into 'bio-fuel' - gas or liquid fuel derived from widely
available renewable resources such as woodchip waste and cereal
crops. This 'biomass' is a particularly interesting energy source
from the environmental point of view, as it is both infinitely
renewable and 'greenhouse neutral' - the CO2 the crop
releases as it is burnt is balanced by an equal amount removed
from the air as it grew. As an added bonus, many kinds of biomass
could provide a major stimulus to rural economies across the continent,
while the technologies can be exported around the world.
Prototype
Pyrolyser
Simply burning the biomass is not, however, very efficient, which
is why the Italian and German partners in one JOULE project(1)
developed an innovative bio-mass powered reactor to generate electricity
for farms and small communities. The reactor uses the pyrolysis
process, in which the biomass is heated to 500°C. Instead of burning,
however, it produces vapours which condense into a dark, brown
liquid that can substitute for fuel oil. This bio-fuel has a much
higher energy density than that produced using classical gasification
methods, and can be stored for long periods and easily pumped
and transported.
The partners studied various crops, finding that sorghum was ideal,
and confirmed that the fuel can be burnt in gas turbines, diesel
engines and Stirling engines, as well as in conventional, oil-fired
boilers. They proved their point by building one of the world's
first prototype systems of this kind - a pyrolyser coupled to
a 100-150 kWe generator - which converted 55-65% of the biomass
into fuel.
(1) -Advanced small
electricity farm generator optimised for herbaceous crops.
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