Semester

Fall

Date of Graduation

1998

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Chemical and Biomedical Engineering

Committee Chair

Edwin L. Kugler.

Abstract

In this study the RE-USY (Davision GO-40) FCC catalyst, a composite of RE-USY zeolite and alumina-silica gel matrix, was treated hydrothermally under simulated FCC regenerator conditions in a laboratory scale fluidized bed. Fresh and steam-aged catalysts were characterized by surface area reduction using the nitrogen BET and t-Plot surface area methods. The surface morphology was apparent from the scanning electron photomicrographs. An irreversible deactivation kinetic model developed earlier by Gardner.; S0- S/S0 ns=Ks t was applied to account for changes of surface area of the zeolite component as a function of time on stream, temperature and steam partial pressure. The kinetic parameters, Ks, the apparent global zeolite hydrothermal stability rate constant and ns, a constant which was determined to be a function of steam partial pressure for a given temperature were determined and compared to those of H-USY (Davision Octacat) FCC catalyst.;An effect of rare-earth exchange on deactivation kinetics was observed. The RE-USY was found to exhibit greater hydrothermal stability than the H-USY determined by the smaller hydrothermal stability rate constant, Ks, and the smaller ns. The presence of rare-earth ions in the zeolite was suggested to prevent extraction of aluminum atoms which caused the hydrothermal destruction of zeolite framework.

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