Date of Graduation
Statler College of Engineering and Mineral Resources
Chemical and Biomedical Engineering
Edwin L. Kugler.
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.
Panpranot, Joongjai, "Hydrothermal aging of zeolite-based catalysts" (1998). Graduate Theses, Dissertations, and Problem Reports. 932.