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.