Propane and propylene adsorption eq

Propane and propylene adsorption equilibrium and kinetics onto a carbon molecular sieve Takeda 4A has been investigated using manometric, ZLC and chromatographic techniques. The selectivity of the material towards propylene at low pressures is around 2 and decreases at higher pressures. Micropore diffusion controls the adsorption kinetics of both hydrocarbons. Amounts adsorbed at very low pressures from manometric and dynamic experiments are coincident allowing a correct estimation of the Henry law constant of both gases. The micropore diffusivity coefficients determined by zero length column technique and the ones determined from the breakthrough model are clearly not coincident and this fact can be explained by the non-uniform size of the micropore structure. Diffusion parameters of propane and propylene determined by breakthrough curves have a difference of two orders of magnitude. Looking at the equilibrium and kinetic data presented in this paper, we can see that this adsorbent can be used in a pressure swing adsorption unit with a kinetic separation scheme and not equilibrium one.