Effect of Foam Films on Gas Diffusion

Novel Aqueous Foams for Suppressing VOC Emission

“…This, in turn, leads to thinner foam films in the presence of salt. Thinner films may not reduce the ability of the foam barrier to suppress VOC emissions substantially if the limiting mass transfer resistance is provided by the film-gas interface (20). Figure 13 shows the cumulative hydrocarbon emissions per liter of gasoline loaded in the emission cell for the foam composition 1T0.4F6G0.24X prepared in saline solution (3.5 wt % NaCl) and the initial foam height of 40 cm.…”

Mass transfer of volatile organic carbons through aqueous foams

“…One conjecture could be that the altered surfactant/polymer ratio decreases D l /H such that the mass transfer resistance shows little change. The second possibility is that the surfactant layer at the gas-liquid interfaces controls the mass transfer [6]. A better understanding of surfactant/polymer interaction and its impact on the effective diffusivity of the foam lamellae is needed to explain this experimental observation.…”

“…Dalland and Hanssen [4] and Mannhardt et al [5] have studied stability of foams in the presence of oil for control of gas flow in oil fields. Although the diffusion of gas across a thin liquid barrier has been modeled [6], there is a dearth of literature on modeling of diffusive mass transfer of hydrocarbons through a standing or collapsing foam column. Brown et al [7] have studied the diffusion of air from bubbles formed in a surfactant solution.…”

Motion of foam films in diverging–converging channels

“…7 also presents the measured dynamic pressure drops at almost same positions as in the static case, compared with the pressure drop profiles according to Eqs. (14), (16).…”

“…Note that Eq. (14) neglects the diffusion of gas across the film, since in our previous work [15,16] we have found foam film resistance to gas diffusion to be significantly high.…”