Date of Award

2014

Document Type

Open Access Dissertation

Department

Chemical Engineering

First Advisor

James A Ritter

Abstract

Because of their numerous important applications in industrial catalytic, separation, and purification processes, miroporous materials have attracted considerable attention. Understanding the dynamic behavior of various gases in these porous materials is a critical step in designing, developing and effective operation of such kind of industrial processes. Frequency response (FR) methods have proven to be one of the best recently developed techniques and have been widely used to investigate kinetics behavior of various gas-solid systems due to their ability to discriminate among different rate limiting mechanisms. The current work has been focusing on the development of a volume swing frequency response system and demonstration of the robustness and applicability of the newly developed system in identifying the mass transfer mechanisms of various adsorbate-adsorbent systems effectively.

A new volume swing frequency response system along with a new approach to analyze the response curve using frequency response simulator is developed. The new system is fully automated and has the ability to characterize more thoroughly over wide frequency spectra thus provide ability to identify both slow mass transfer resistances and fast mass transfer resistances that do not visible at lower frequencies. The strength and the robustness of the developed frequency response analysis has been successfully demonstrated for study the adsorption kinetics of CO2 and N2 in commercial 13X zeolite pellets and O2, N2 and Ar in CMS materials. In this work, the newly developed frequency response system and new analytical approach is discussed in details. The experimental procedure and the method of analysis have been demonstrated for two commercially available adsorbent materials for various gases. The new system is able to identify the key mechanisms for CO2 and N2 in13X zeolite and for O2, N2 and Ar in CMS adsorbent. The findings are quite consistent with the available literatures. Additionally, a new and modified expression for the estimation of cycle time dependent LDF mass transfer coefficient have been proposed for diffusion limited mass transfer processes which could be used for both slow and rapid cycling processes.

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