Petroleum cracking catalyst characterization

This paper reports on the characterization of petroleum cracking catalysts, with which a third of the world's crude oil is processed, which presents a formidable analytical challenge. The catalyst particles are in the form of microspheres of 60-70 micron average diameter which are themselves composites of up to five different micron and submicron sized phases. In refinery operation the catalysts are poisoned by trace concentrations of nickel, vanadium and other contaminant metals. Due to the replacement of a small portion of equilibrium catalyst each day (generally around 1% of the total reactor inventory) the catalyst particles in a reactor exist as a mixture of differing particle ages, poisoning levels and activities. Direct imaging SIMS has been shown to be capable of viewing both the phases and contaminants within individual catalyst particles, and differences from particle to particle. Multiple image processing techniques now allow the rapid analysis of the relative concentrations of several elements (normally 6-8) on a large number of particles (50-100) using multiple low magnification SIMS images