The microwave-generated steam treatment of contaminated soil is based on incrementing the temperature by microwave energy irradiation in the presence of a sufficient moisture amount. Therefore the previous knowledge of the temperature distribution in the irradiated soil is essential for the correct application of the treatment. In this work a mathematical model was developed to describe the heat and the mass transfer evolution in a soil-water system during the microwave remediation. The time-dependent model was based on mass and energy conservation equations and had the purpose to outline the temperature and humidity variations during the time and along the soil sample depth. As a preliminary drafting of the model the following assumptions were made: 1) no reactions in the soil, 2) no radial moisture and temperature gradients. A key role is played by the overall dielectric properties which drive the absorption of energy by the soil and, at the same time, are subjected to change with moisture content and temperature. Microwave heating was performed on laboratory-scale experiments, measurement of temperature and residual moisture amount were carried out during the time and along the sample depth. The agreement between the experimental values and the numerical results was appreciable both for the temperature and the moisture amount. Further tests with linear hydrocarbons (noctane, n-decane, n-dodecane, etc…), mixture of them and kerosene confirmed the necessity of an optimum moisture content in the soil in order to achieve a costeffective use of microwaves for soil decontamination.
Soil Remediation by Petroleum Products: Modeling and Experimental Investigation of Microwave Treatment
CIONI, BEATRICE;GALLONE, GIUSEPPE CARMINE;PETARCA, LUIGI
2005-01-01
Abstract
The microwave-generated steam treatment of contaminated soil is based on incrementing the temperature by microwave energy irradiation in the presence of a sufficient moisture amount. Therefore the previous knowledge of the temperature distribution in the irradiated soil is essential for the correct application of the treatment. In this work a mathematical model was developed to describe the heat and the mass transfer evolution in a soil-water system during the microwave remediation. The time-dependent model was based on mass and energy conservation equations and had the purpose to outline the temperature and humidity variations during the time and along the soil sample depth. As a preliminary drafting of the model the following assumptions were made: 1) no reactions in the soil, 2) no radial moisture and temperature gradients. A key role is played by the overall dielectric properties which drive the absorption of energy by the soil and, at the same time, are subjected to change with moisture content and temperature. Microwave heating was performed on laboratory-scale experiments, measurement of temperature and residual moisture amount were carried out during the time and along the sample depth. The agreement between the experimental values and the numerical results was appreciable both for the temperature and the moisture amount. Further tests with linear hydrocarbons (noctane, n-decane, n-dodecane, etc…), mixture of them and kerosene confirmed the necessity of an optimum moisture content in the soil in order to achieve a costeffective use of microwaves for soil decontamination.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
