Effects of adsorbed phase on diffusion of subcritical hydrocarbons in activated carbon at low pressures
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Abstract
Diffusions of free and adsorbed molecules of subcritical hydrocarbons in activated carbon were investigated to study the influence of adsorbed molecules on both diffusion processes at low pressures. A collision reflection factor, defined as the fraction of molecules undergoing collision to the solid surface over reflection from the surface, is incorporated into Knudsen diffusivity and surface diffusivity in meso/macropores. Since the porous structure of activated carbon is bimodal in nature, the diffusion of adsorbed molecules is contributed by that of weakly adsorbed molecules on the meso/macropore surfaces and that of strongly adsorbed molecules in the small confinement of micropores. The mobility of adsorbed molecules on the meso/macropore surface is characterized by the surface diffusivity Dμ2, while that in the micropore is characterized by Dμ1. In our study with subcritical hydrocarbons, we have found that the former increases almost linearly with pressure, while the latter exhibits a sharp increase at a very low-pressure region and then decreases beyond a critical pressure. This critical pressure is identified as a pressure at which the micropores are saturated.
References
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- Effects of adsorbed phase on diffusion of subcritical hydrocarbons in activated carbon at low pressures
- The Boussinesq approximation in a rotating frame of reference
- Self-organised marangoni motion at evaporating drops or in capillary menisci – thermohydrodynamical model
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Articles in the same Issue
- Effects of adsorbed phase on diffusion of subcritical hydrocarbons in activated carbon at low pressures
- The Boussinesq approximation in a rotating frame of reference
- Self-organised marangoni motion at evaporating drops or in capillary menisci – thermohydrodynamical model
- A study of thermodynamic stability of deformation in visco-elastic fluids by Lyapunov function analysis
- Thermo-mechanical systems with several heat reservoirs: maximum power processes
- Thermodynamic relationship between creep crack growth and creep deformation
