What is Biomass Gasification?
Biomass can
be described as “stored solar energy”.
AES has secured proven biomass
technology that harnesses the
stored power in biomass materials using a process called
gasification. Gasification is the cleanest combustion
method available, and is at the core of each AES biomass technology offering.
The term "gasification" has,
confusingly, taken on multiple definitions depending on the
entity using the term.
AES subscribes to the
predominant meaning. Wikipedia defines gasification
as follows:
Gasification is a process
that converts carbonaceous materials such as coal, petroleum,
petroleum coke or biomass, into carbon monoxide, hydrogen and
carbon dioxide.
In the gasifier,
the carbonaceous material undergo three processes:
1. The pyrolysis (or devolatilization)
process occurs as the carbonaceous particle heats up. Volatiles
are released and char is produced, resulting
in up to 70% weight loss for coal. The process is dependent
on the properties of the carbonaceous material and determines the structure
and composition of the char, which will
then undergo gasification reactions.
2. The combustion process occurs as the volatile products and some of the char
reacts with oxygen to form carbon dioxide and carbon monoxide, which provides
heat for the subsequent gasification reactions. Pyrolysis and combustion are
very rapid processes.
3. The gasification process
occurs as the char reacts with carbon dioxide and steam
to produce carbon monoxide and hydrogen. The resulting
gas is called producer gas or syngas (or wood gas when
fueled by wood) and may be more efficiently converted to
energy such as electricity than would be possible by direct
combustion of the fuel, as the fuel is first combusted
in a gas turbine and the heat is used to produce steam
to drive a steam turbine.
Also, corrosive ash elements such as chloride and potassium may be refined out
by the gasification process, allowing high temperature combustion of the gas
from otherwise problematic fuels.
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source: http://en.wikipedia.org/wiki/Gasification
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No Slurry. No Sludge. Just Saleable Ash
Not to be confused with a digester which
extracts methane from wet biomass to then be combusted,
the gasifier uses
a high heat, oxygen depleted environment to produce syngas
which is then mixed with
air and creates the heat to produce hot water, hot air
or steam. Biomass fuel is
supplied directly into the combustion chamber, which can
accept completely
dry biomass or quite wet biomass- up to 120% moisture on
a dry basis.
We leave no
pollutants to be pumped out and disposed of. Saleable ash
is the only byproduct of our process, which can represent
a new revenue stream. The ash produced
by the gasifier can
be used as a construction filler in asphalt and soil cement
as well as a soil amendment for
growers
or as a coating used by seed producers.
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