A laboratory study on foam-enhanced surfactant solution flooding in removing n-pentadecane from contaminated columns

The efficiency of a foam flooding process in removing n-pentadecane from a contaminated glass-bead column was evaluated by comparing with the results obtained by a surfactant-solution flooding process. Data on the foaming properties and solubilization efficiency of aqueous surfactant solutions were reported. Moreover, an experimental column containing n-pentadecane-contaminated glass beads was used to explore the effects of surfactant concentration and gas-liquid volumetric flow rate ratio on the recovery efficiency of n-pentadecane. It was found that the efficiency of a surfactant solution in recovering n-pentadecane increased with increasing surfactant concentration. The findings also suggest that in this study the surfactant-enhanced emulsification of n-pentadecane played an important role in removing n-pentadecane from the contaminated column. Using foam flooding, the recovery of n-pentadecane was increased significantly compared with what obtained by surfactant-solution flushing, probably due to the reduced channeling flow effect. These data demonstrated that the dramatic improvement in residual n-pentadecane recovery can be realized by the use of foam. In addition, at a constant liquid flow rate, an increase in gas-liquid volumetric flow rate ratio may result in increased total n-pentadecane recovery. (C) 2000 Elsevier Science B.V. All rights reserved.