Investigating vertical and lateral gas migration during thermal conduction heating in heterogeneous porous media

Abstract

The successful treatment of contaminated soil and groundwater using thermal remediation technologies relies on the capture and treatment of contaminant vapour produced during heating. The migration of that vapour is affected by subsurface heterogeneity, which must be understood to ensure capture and to prevent condensation outside of a target heating zone. Bench-scale thermal conduction heating experiments were conducted to investigate the migration of steam through homogeneous and heterogeneous porous media. The steam pattern was parabolic adjacent to the heater during homogeneous experiments. In heterogeneous experiments, gas accumulation and migration were observed underneath the capillary barrier. Despite a connected gas pathway to the atmosphere, the transmissivity of the capillary barrier was not sufficient to prevent this migration. This has implications for the transport of heat and contaminant vapour outside of the heated zone, emphasizing the need for effective vapour capture.