Nonequilibrium mass transfer of multicomponent NAPL in a soil column venting

This study was conducted to investigate the mass transfer behavior for a mu lticomponent system in the soil venting process. Soil venting experiments w ere conducted using gasoline-contaminated soil and models of local equilibr ium assumption (LEA) and the first-order kinetic approach were used to desc ribe the gasoline volatilization process. However, the focus was on the app lication of the kinetic model In both models, thirteen major components of gasoline were selected for the model input and the rest of the gasoline was divided into 11 groups based on the retention times in the gas chromatogra phy of gasoline. The LEA model had the tendency of underestimating the gas concentration at the initial phase and overestimating at the later phase du e to the different volatilities of multi-components. In the kinetic model t he estimation of mass transfer coefficient values were carried out by adopt ing the relationship developed in the single-components system and choosing the appropriate modified Sherwood number. This method resulted in the good agreement with the simulation and the experimental results.