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Deffinition of
Pyrolysis Technology:
Pyrolysis technology
According to the U.S. Department of Energy, pyrolysis is "the thermal
distillation or decomposition of organic materials into oils, gases,
and char." Pyrolysis process is usually conducted in a reactor
where heat is applied either internally or by partial combustion of
feed materials. When organic material is heated in a non-reactive atmosphere,
the devolatilization results in vapor, gas and char products. The products
are cooled below their dew point in a condenser and the condensed liquids
are obtained. The char is carbon-rich, nonvolatile solid residue. Pyrolysis
can be carried out in fixed bed or in fluidized bed. Fixed bed system
is considered in this study. The fluidized bed system is more complex
and more coke is formed. The products usually obtained in a pyrolysis
process are liquid, char and gas. The process of pyrolysis of organic
matter is very complex and consists of both concurrent and consecutive
reactions, which results in variety of products. Reaction concepts for
organic solids are shown in Fig: 1.2
Pyrolysis products Combustion pathway
Fuel Volatiles Flaming Combustion
Organic Tar
Solids
Char Glowing Combustion
The global pyrolysis / combustion model proposed by Shafizadeh (1985)
The relative proportions of the pyrolysis product depend on both the
process parameters as well as the composition of the feedstock Depending
on the operating condition; pyrolysis process can be divided in to three
main groups, namely carburization, conventional or slow pyrolysis and
fast pyrolysis or flash pyrolysis.
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