Low Temperature Thermal Desorption (LTTD) – Direct Heated

Low Temperature Thermal Desorption (LTTD) – Direct Heated

Operating at our Bedford facility since 1995, our Low Temperature Desorption Unit is capable of treating hydrocarbon-impacted soil at a rate of 35-40 tonnes per hour, at an average concentration of 2.5 - 3%. Since being commissioned, over 600,000 tonnes of hydrocarbon-contaminated soil has been treated to non-detectable levels.

The thermal unit is fuelled by recycled waste oil. This practice of reusing a common waste product (crank case oil) is in keeping with our efforts to remain vigilant and employ whatever strategies are necessary to help enhance the environment. Of course, other fuels may be used if they prove to be acceptable and beneficial.

Our Low Temperature Thermal Desorption (LTTD) has been designed and constructed to effectively purify soils contaminated with various organic contaminates including: petroleum hydrocarbons, pesticides, PAHs, and chlorinated compounds. The system is designed to be both versatile and highly portable.

The system is based on the concept of Low Temperature Thermal Desorption (LTTD), which is the process of contaminant removal by transforming contaminants from one phase to another. The system targets an operational temperature which is slightly greater than the highest boiling point of the compounds under treatment, but less than the auto-ignition temperatures. As the soil 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 physical transfer from the liquid phase to the vapour phase.

The gases are then removed by negative pressure and routed into a secondary combustion chamber where they are further heated to a point above the auto-ignition temperatures of the specific compounds. The result of this process is a transformation of organic compounds into carbon dioxide and water.

The gas stream, now consisting primarily of carbon dioxide and water, enters an evaporative cooling chamber (ECC), where the gases are cooled prior to the final exhaust gas treatment in the baghouse. The particulate matter in the gas stream is intercepted in the baghouse and returned to the soil discharge system. The gases are discharged from the baghouse stack, which has continuous monitoring.