Chapter 6 Instrumental Methods of FCC Catalyst Characterization

Abstract

The Fluid Catalytic Cracking (FCC) catalyst is a coarse powder consisting of particles in the 40 to 100 micron size range with an average size of about 65 microns. It contains 20% to 50% of an active zeolite, usually faujasite, with a surface area of 900 meters2/gram. Instrumental methods are used to characterize the FCC catalyst particle, both fresh and after deactivation. The catalyst properties—such as zeolite content, the unit cell size of the zeolite, and the content and location of the active components—determine the activity and selectivity of the catalyst. Catalyst stability is measured by comparing the fresh properties of the catalyst with the properties of the operating or equilibrium catalyst. In most advanced technology catalysts, the zeolite is designed to hydrothermally dealuminate in a controlled and stable way to the intended unit cell size and surface area. The hydrothermal environment of the unit is, in a sense, part of the catalyst preparation. Also, during the use of contaminant, metals contained in the oil at the part-per-million level may deposit on the catalyst and cause changes in activity and selectivity. The control of these contaminants is one of the most important issues in catalytic cracking. It is important for the catalyst user, the manufacturer, and the researcher to be able to follow the chemical and physical changes that take place during the operation of the catalyst in the FCC Unit (FCCU). The operation of the FCCU is also described in the chapter.