Semester

Fall

Date of Graduation

2003

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Chemical and Biomedical Engineering

Committee Chair

Hisashi O. Kono.

Abstract

This dissertation comprised two parts, which were Part I for the development of a method to characterize the fine powder flow at ambient temperature and Part II for the application of the method in fine powder aeration at elevated temperature.;The analysis conducted on fine powder aeration in Part I was based on the theory of homogeneously-aerated-expanded (HAE) emulsion phase, which viewed a system of aerated fine powders as a quasi-solid single phase.;The original aeration data from an aeration experiment (gas velocity, pressure drop, and bed height) were transformed into the new variables specifically defined for aerated fine powder (powder strain and powder tensile stress). The plots of powder tensile stress against powder strain indicated a consistent tendency for all experimental data. Based on this fact, a parameter called elastic deformation coefficient (Y) was determined from those plots and defined as the characterization parameter for fine powder aeration behaviors.;The point of intrinsic Umb could be accurately determined as the point of sudden change of Y value on the plot of Y against powder strain. These Y values also provided a quantitative tool to compare the aeration quality of several different systems of fine powders.;In Part II, to study the effect of temperature on aeration quality, the Y method was applied on aerated FCC catalyst at temperatures ranged from 26°C to 600°C.;At ambient temperature, the aeration quality of FCC catalyst was very poor and it was indicated by an initially high Y which kept increasing through the whole range of strain until the maximum expansion. In contrast to that, at elevated temperature, a region of constant Y was observed in the plot of Y against strain. This fact indicated that at high temperature, an ideal HAE emulsion phase could be maintained over a wide range of strain before the first fractures occurred. These results showed that Y value served as a general characterization parameter that could be applied consistently at both ambient and elevated temperature.

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