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Low Temperature Thermal
Recovery – Indirect Heated
At capacity this
leading-edge technology can treat hydrocarbon-impacted
soil at a rate of 10-12 tonnes per hour at an
average concentration of 10-15%.
The system is designed to
recover hydrocarbon product from impacted soil
materials. The recovered hydrocarbon is recycled
and can be used as a fuel for the unit or for
other hydrocarbon applications. The treated soil
is then recycled as site restoration material.
The thermal unit is currently powered by the cleanest
fuel available - natural gas - and has the capability
of using other fuels.
The early success of this innovation
has placed it in high demand and kept it busy,
particularly in Southeast Asia where it currently
operates.
The Envirosoil Indirect Thermal
Recovery System has been designed and constructed
to treat materials contaminated with hydrocarbon
compounds. The function of the indirect system
is to heat contaminated materials while separating
the heat source combustion products from the contaminants.
The indirect heated thermal desorption unit is
coupled with an externally fired burner system,
which provides heat for the thermal processor.
The off-gases from the processor contain moisture
and vaporized hydrocarbon contaminants, which
were originally present in the contaminated media.
These off-gases are then routed into a Primary
Separator, scrubber system, condenser system and
thermal oxidizer for hydrocarbon recovery and
control of emissions discharge from the process.
Although the system was designed and constructed
for treatment of materials impacted with hydrocarbon,
additional organic contaminates may be treated
with the same system, with little or no modification.
The system is
based on the concept of thermal desorption which
is the process of contaminant removal by transferring
contaminants from one phase to another. The system
is operated by targeting an operational temperature
based on the boiling point range of the compounds
under treatment, and lower than the auto?ignition
temperatures. As the material is heated to this
point, the contaminants reach their respective
boiling points at which time the compounds vaporize
and become part of the gas stream. This removal
mechanism is a physical transfer from the liquid
phase to the vapor phase. The gases are then removed
by negative pressure and routed into the off-gas
treatment system. In the off-gas treatment portion
of the process the gases are cooled, scrubbed,
then chilled to promote condensation for removal
of organic contaminates and also for capture of
particulate. Finally, the treated gases are routed
into a thermal oxidation chamber for oxidation
of any non-condensable residual gases.
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