(402c) Understanding the Transport of Gases in Carbon Molecular Sieve Using the Volumetric Frequency Response Technique

Frequency response methods have been developed as an alternative technique for the determination of mass transfer mechanisms controlling the transport of gases into and out of microporous adsorbent materials. Recent results in the literature are showing that this technique seems to be the best for discriminating the controlling mechanism. It is also possible to reveal two or more different controlling mechanisms that may dominate in different frequency ranges. The present talk will focus on the use of the volumetric frequency response (VFR) approach for the identification on the main mechanism governing the transport of gases such as O₂, N₂ and CO₂ in pelletized and ground molecular sieve carbon (MSC 3K 172 from Japan Enviro Chemicals, Osaka, Japan). In a recently commissioned VFR apparatus, experiments were carried out with pure gases at pressures of 200, 400 and 750 Torr, temperatures of 20, 30, 40 and 50 ^oC and frequencies between 0.7×10^-5 and 10 Hz using pelletized CMS. Additional experiments were conducted at 750 Torr and 30 ^oC using a ground sample of this CMS with particle sizes between 30-50 Tyler mesh. The results are showing that the transport mechanism can be unequivocally identified when fitting the frequency response curves to various transport models. The results are also revealing that conducting FR experiments at different temperatures and pressures, as well as using different particle sizes helps to ensure that the correct transport mechanism has been identified. During this presentation the latest results obtained from the system will be presented and interpreted.