08-16-2017, 09:21 PM
Waste plastic to clean fuel
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An innovative solution, pioneered and
commercialised in Japan, could help
Australia reduce greenhouse gas emissions
and the coal loads required by the iron
and steel industries.Waste plastic will be
used as a fuel in blast furnaces at ironworks,
rather than heading for landfill,
if a new scoping study by the Cooperative
Research Centre for Coal in Sustainable
Development (CCSD) confirms the
process s feasibility.
In a traditional blast furnace, coal used
to fuel the furnace acts as a reducing agent
for the conversion of iron oxide (FeO) into
iron (Fe). This reduction reaction occurs
when carbon monoxide gas (CO), released
from the burning coal, combines with the
oxygen molecule from iron oxide to
produce iron and carbon dioxide (CO2).
When plastic (a long chain hydrocarbon) is
added, however, hydrogen molecules from
the plastic combine with oxygen to
produce water (H2O), iron and reduced
amounts of CO2.
This technology will only be practical in relative proximity to a blast furnace, of which there are three in Australia
The plastic injection technology,
successfully commercialised in Japan, helps
reduce some 3.25 million tonnes of waste
plastic buried in landfills each year. A ratio
of about 10% plastic to coal is used in
these commercial operations, but there is
potential for this ratio to increase significantly.
Before this happens, however,
further research is needed to understand
what happens inside a blast furnace when
plastic is added.
The CCSD scoping study aiming to
elucidate these unknowns is led by
Professor Veena Sahajwalla of the
University of New South Wales, in collaboration
with BHP Billiton and Japanese
scientists from Kyoto University and steel
producer JFE.
When you add plastic it changes the
chemistry of the blast furnace, Sahajwalla
says.