APPLICATION OF H-NMR FOR FCC FEED CHARACTERIZATION

摘要

Feed is considered the most influential single factor affecting the FCC unit performance. Chemical composition of the FCC feed affects yields and quality of products. The FCC feed properties strongly depend on two factors: the geographic source of the crude and initial preprocessing. To make things even more complicated, FCC feeds are usually blends of multiple feed sources and refinery recycle streams, some of them very poor quality. Therefore knowing molecular composition and concentrations of a complex feed is essential not only for optimal FCC unit operations but also for the process of catalyst selection and product yields prediction. Current analytical techniques for feed characterization provide helpful information about feed quality, but they are not adequate to provide the identities and concentrations of the molecules in commercial FCC feeds. Over the years, methods have been developed, mostly in the form of heuristic correlations, to predict important FCC feed properties, with a goal to relate these feed quality characteristics to product yield and qualities. However, there are certain limitations in employing these techniques that include the range for which the correlation was developed and assumptions and mathematical manipulation involved in the derivation of the formula.