Kinetics of spontaneous water-N imbibition in carbon molecular sieves.

In this study, a new kinetic model of spontaneous liquid-gas imbibition (SLGI) for microporous adsorbents has been developed. With three carbon molecular sieves (CMS) as adsorbents, N as gas probe and water as liquid probe, the kinetics of spontaneous water-N imbibition in CMS has been investigated at atmospheric pressure, and the applicability of the kinetic model to the SLGI has been assessed. The influences of the particle size of CMS and the experimental temperature in the range of 20-35 °C on the imbibition process have been analyzed based on the kinetic model. The relations between the kinetic parameters of the SLGI and the microporous parameters of the CMS obtained by CO adsorption at 273 K have been elucidated. The results indicate that the imbibition process is controlled by the diffusion of the water molecules into and N out of the micropores and the adsorption of the water on the pore surface of the CMS. The equilibrium gas recovery is positively related with the micropore volume, and the gas recovery rate depends mainly on the micropore size of the CMS.