Effect of plateau pressures on absorption breakthrough curves of hydrogen with metallic particle beds -numerical calculations-

An analytical investigation is made on the recovery of hydrogen isotopes to a level of very low concentration by means of a metallic particle bed. Our attention is focused on the effect of plateau pressures in equilibrium isotherm on the shapes of absorption breakthrough curves of hydrogen. A dimensionless material balance equation is numerically calculated, taking account of the effects of axial dispersion and the resistances of external diffusion, internal diffusion and surface reaction. If the equilibrium isotherm intersects the line of x=y_mon the x—y_mdiagram, a plateau zone is found on breakthrough curves. The width of the plateau zone increases with increase of bed height, and two independent mass transfer zones go through the bed with different propagation velocities. On the other hand, the plateau zone occasionally emerges in the developing region close to the inlet of the bed even when the two lines do not intersect.