Analysis of carbon dioxide mass transport in molecular sieves

This study investigates the possibility of installing a portable devise in the vehicle exhaust system to capture most of the generated carbon dioxide. Although the experimental system in this thesis is simple, the theoretical analysis is somehow complicated. The experimental system involved the adsorption/diffusion of carbon dioxide on various porous solids at different pressures. The porous solids are molecular sieves 13X and 4 A. A system is designed to gather experimental data. The recorded data are the mass of carbon dioxide trapped in the molecular sieves, pressure of the vessel and time of mass transport. The carbon dioxide initial pressure is 22 psi. The first order Fick's law is used to determine the diffusivity coefficient. The unsteady state second order Fick's law is used to study the carbon dioxide bulk concentration along the porous solid bed. The porous solid bed length is 5.1 mm. The molecular sieve 13X shows a better gas mass transport than molecular sieve 4 A. When comparing the rate of carbon dioxide mass trapped in molecular sieve 13X to the emission of carbon dioxide rate from vehicle, it is clear that the design product should be made of molecular sieve 13X.