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CONCURRENT INJECTION OF COSOLVENT AND AIR FOR ENHANCED PCE REMOVAL
Citation:
Jeong, S. W., A L. Wood*, AND T R. Lee*. CONCURRENT INJECTION OF COSOLVENT AND AIR FOR ENHANCED PCE REMOVAL.
Description:
The goal of this study was to use preferential flow of air to improve the dynamics of cosolvent displacement in order to enhance DNAPL displacement and dissolution. The concurrent injection of cosolvent and air was evaluated in a glass micromodel for a DNAPL remediation technology. A micromodel analysis is a means to help quantify exact DNAPL saturation and visualize pore-scale phenomena in the porous medium. Three cosolvent solutions (50% ethanol/50% water, 70% ethanol/30% water, and 90% ethanol/10% water, by volume) were injected simultaneously with air into a glass micrornodel containing residual tetrachloroethylene (PCE). Flushing with the cosolvent solutions without concurrent air injection was also compared with the cosolvent-air floods. This study measured specific surface areas (unit blob volumes) of PCE blobs during cosolvent-air (CA) flooding and cosolvent (CS) flooding to show the degree of contact between injected fluids and PCE. Specific surface area increased over time during CA flooding, but remained relatively constant during CS flooding. The results show that PCE blobs were segmented into small blobs in an initial period of the CA flooding and then the small blobs gradually shrink during flooding. The concurrent injection of cosolvent and air improved the flow distribution and dynamics of the cosolvent solution. Facilitated dissolution of PCE was observed throughout the porous medium during CA flooding.