Showing papers by "M. Douglas LeVan published in 1992"

Coadsorption of hydrocarbons and water on BPL activated carbon

Abstract: A novel experimental apparatus is used to measure hexane, acetone, water, hexane/water, and acetone/water isotherms on BPL activated carbon. Isotherms for pure components are measured from 25 to 125°C with hydrocarbon pressures varied by a factor of 10 7 , from low values to saturation. Emphasis is placed on measuring the hysteresis loop in the water and hydrocarbon/water systems. For adsorption of pure water, the location and size of the hysteresis loop is found to be temperature dependent, with the loop shifting toward higher relative pressures and narrowing as temperature is increased. For the hydrocarbon/water mixtures, the hydrocarbon loading is held constant and water isotherms are measured at 25 and 100°C. The partial pressure of the hydrocarbon is found to increase dramatically at constant hydrocarbon loading as the water loading is increased. Also, hysteresis is observed in the hydrocarbon partial pressure depending on whether the system is on the adsorption or desorption branch of the water isotherms. Behavior is complex and is interpreted qualitatively

Effect of intraparticle forced convection on gas desorption from fixed beds containing large-pore adsorbents

Abstract: The importance of intraparticle convection on the desorption of gases from fixed beds with large-pore adsorbents is assessed on the basis of modeling studies. A complete model for isothermal fixed-bed desorption of linear and nonlinear absorbed species includes axial dispersion, intraparticle diffusion, and intraparticle forced convection. Velocity and total pressure changes in the bulk fluid phase as well as in the intraparticle fluid are considered. In this paper several limiting cases are shown as simplifications of the complete model. In a certain range of the number of intraparticle diffusion units, intraparticle forced convection leads to a better efficiency of the desorption process. This is a consequence of the augmented effective diffusivity by convection inside the adsorbent particle.