Steady-state analysis of the fate of volatile contaminants during In situ Vitrification
Year: 1992
Type: report
Abstract: A mathematical simulation has been developed to describe the transport of water, steam, and trace concentrations of volatile contaminants in soil during the application of the In Situ Vitrification (ISV) process. The ISV process creates a mass of molten soil that grows during processing. Testing has shown that the vast majority of water encountered and vaporized by the growing melt is expelled from the soil and directed to an off-gas treatment system. The simulation addresses the question: under what conditions will other volatile species also be expelled from the soil and be directed to the off-gas system (or oxidized or pyrolyzed in transit)? The simulation is based on an assumed spherical symmetry of temperature, liquid saturation, and contaminant concentration profiles adjacent to an assumed expanding hemispherical melt. A set of coupled, nonlinear ordinary differential equations are solved numerically to predict the transport of water and steam in two regions: a boiling region (essentially a heat pipe) assumed to be devoid of air, and a diffusion region assumed to be at constant pressure. The results of the simulation are presented in terms of the degree of sorption in soil required to predict that the contaminant is captured by the growing ISV melt. Results are presented for carbon tetrachloride, benzene, and acetone. The results are very favorable for acetone; success in capturing immiscible species such as carbon tetrachloride depend on the organic content of the soil, which affects sorption of organic species.
DOI: 10.2172/10146361
Language: English
Subfield: Environmental Engineering
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1607673131