Developing interphase mass transfer correlations for non-aqueous phase liquid to gas in porous media with thermal enhancement

Authors: Xiaobin Liu, Heng Li, Jianfei Wu, Wenjie Wu, Wei Zhang, Qingbiao Li*, Yanmeri Zheng*

Abstract: An in-depth understanding of interphase mass transfer from a non-aqueous phase liquid (NAPL) to a gas is crucial and indispensable for properly designing and optimizing remediation schemes in NAPL-contaminated sites involving thermal treatment. A series of polluted soil column venting experiments were conducted to thoroughly evaluate this nonequilibrium behavior at both the initial steady-state stage and transient stage of mass transfer. Two new correlations are proposed to predict the mass transfer efficiency and duration of the steady-state stage. Additionally, it is proposed the disparity of behavior in the transient stage is caused by different modes of interfacial area reduction, which are controlled by two competing phenomena: NAPL film spreading, and evaporation at the NAPL–gas interface. These processes are described by specific mathematical expressions. These findings provide deep insight into thermally enhanced NAPL–gas interfacial mass transfer and have the potential to be applied to modeling studies and field applications of multiphase extraction.

Link: https://www.sciencedirect.com/science/article/pii/S0009250922008557