In-situ thermal desorption of contaminated surface soil

摘要

An in-situ thermal desorption system utilizes perforated or slotted pipe buried in the soil below the depth of contamination in the soil. The surface of the soil is covered with a layer of permeable insulation (to conserve heat and to provide a gas migration path on top of the soil) and a layer of impermeable material above the insulation. A vapor recovery/treatment system consists of a method of inducing a vacuum between the impermeable layer and the soil surface (e.g., a vacuum pump or an induced draft fan) and a treatment system for the contaminated vapor (e.g., a cold trap, carbon adsorption, or incineration). Fuel and compressed air are fed to a pressurized combustion chamber and combusted, the combustion products flow into the buried pipe and are distributed through the contaminated soil. Heat from the pressurized combustion products causes the organic contaminants within the soil to vaporize, pyrolyze, decompose, or react with oxygen. Contaminants and their by- products are swept away by the combustion products into the vapor recovery/treatment system.