Heat and Mass Transfer during Microwave Steam Treatment of Contaminated Soils
Publication: Journal of Environmental Engineering
Volume 126, Issue 12
Abstract
A time-dependent mechanistic model has been developed to describe the coupled heat and mass transfer during microwave steam treatment of contaminated soils. The model consists of multiphase mass and energy conservation equations, along with various temperature-dependent parameterizations of important physical state properties. The coupled nonlinear equations were solved numerically by applying a macroscopic control volume method with the appropriate boundary and initial conditions and using a finite-difference scheme. Microwave heating experiments of soil samples were performed. The effects of microwave power, soil sample depth, and soil type on water evaporation rate and temperature were measured with time. The modeled results are in good agreement with the experimental data. The results revealed that microwave power density and soil sample depth significantly affect the microwave evaporation process of water from soils. Water evaporation rate and temperature variation are complex and associated with the dielectric properties of liquid water distributed within the soil. The deeper the soil sample, the more nonuniform the evaporation process, although nonuniformities diminish as the evaporation process approaches completion. Finally it was verified that soil types and their thermal properties play a minor role, provided that the soil minerals are microwave transparent.
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 126 • Issue 12 • December 2000
Pages: 1108 - 1115
History
Received: Nov 23, 1999
Published online: Dec 1, 2000
Published in print: Dec 2000
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