The Emission Characteristics of Pollutants from Thermal Desorption of Soil Contaminated by Transformer Oil

Abstract

In order to reduce pollutant emission from substation fires into the soil environment, developing technology to remove pollutants in soil after substation fires is necessary. Among the soil remediation technologies, thermal desorption has been proven to be an effective soil remediation method. In this paper, the effects of thermal desorption temperature and atmosphere on the releasing characteristics of pollutants in the soil polluted by waste oil in the accident oil pool in the substation were examined. The results showed that when the thermal desorption temperature was 500 °C, a large number of macromolecular organics decompose from the solid phase and change into long-chain alkanes and macromolecular acids under pure N2 atmosphere. When the thermal desorption temperature was higher than 500 °C the pollutants in the soil were further decomposed into small molecular organics. In addition, the organics were transformed to CO2, SO2, NOx, and CO under 20% O2/N2 atmosphere when the temperature was above 500 °C.