Relating FTS Catalyst Properties to Performance

One apparent mode of deactivation is the accumulation of wax in the interior of the catalyst pellet. This route of deactivation decreases the conversion by limiting access of reactants to the interior of the catalyst pellet, especially in the case of the cobalt catalyst. Using various catalyst sizes, we will attempt to develop a quantitative measure for this aspect of catalyst deactivation and thereby define the optimum size for the catalyst particle, allowing us to obtain the maximum effectiveness of the catalyst. Research will also be conducted to define the role that sintering - catalyst particle growth by processes such as agglomeration and ripening - has on the deactivation of the catalyst. Investigations will be defined and conducted in order to identify and quantify other possible modes of catalyst deactivation (e.g., carbon deposition). Kinetic data will continue to be collected and jointly published with NASA personnel. As part of this study CAER personnel will prepare and provide to NASA GRC 100 gram samples of at least three cobalt and four promoted iron catalysts. The optimum FT catalyst produces about 50% of the products in the wax range. One approach to convert the wax to transportation fuels is hydrocracking. Preliminary studies have been conducted with six catalysts provided by a catalyst manufacturer; however, these catalysts produced more gasoline range products than the desired jet and diesel fuel range products. Thus, included in the proposed work will be the preparation and evaluation of acidic catalysts that should have better selectivity for the desired products (e.g., high quality jet fuels). CAER personnel have developed sophisticated advanced techniques to characterize both fresh and used iron and cobalt catalysts. In addition to CAER equipment used to carry out characterization (e.g., adsorption, infrared, temperature programmed, and diffraction methods), CAER personnel frequently utilize equipment at other locations (e.g., University of Kentucky Electron Microscopy Center, Argonne National Laboratory, and Brookhaven National Laboratory). These advanced techniques, some of which require the use of synchrotron radiation, will be employed to characterize at least two, and likely more, catalysts generated by NASA personnel and additional samples provided by the CAER work. The CAER has scientists and engineers dedicated to running slurry phase reactors, analyzing the Fischer-Tropsch products (e.g., oils, waxes, etc.), and characterizing the catalyst structure. CAER houses 23 continuously stirred tank reactors and the necessary analytical and catalyst characterization equipment, allowing us to begin work as soon as the contract is awarded. Thus, none of the contract period would need to be dedicated to startup. Among the deliverables are: - a definition of the aging of iron and cobalt catalysts, especially with respect to wax accumulation, - a more complete definition of the kinetics for iron and cobalt catalysts, leading to continued joint publications with NASA personnel, - samples of iron and cobalt catalysts provided to NASA - a more detailed kinetic description for the synthesis with iron and cobalt catalysts, and - a much better description of the hydrocracking needed to optimize the yield of jet fuel. FORM NRESS-