Kinetic analysis of hydrocracking

Abstract

Hydrocracking feedstocks contain a wide variation in the concentration of various compunds types, i.e. paraffins, mono and polycyclo paraffins and mono and cyclo-aromatics. Typical hydrocracking feedstocks, like vacuum gasoil (VGO) and coker gasoil (CGO) contain large fractions of mono and polyaromatics (approx. 50 %). On a bi-functional catalyst, i.e. hydrogenation and cracking sites, the aromatic rings is subsequent hydrogenated and cracked. The hydrocracking kinetic model developed for aromatic feed on bifunctional catalyst is based on the individual steps of both hydrogenation and cracking. Under steady state process conditions the rate equation of both reactions can be reduced to first order kinetics in respect to the reactant organic compounds. The developed kinetic model predicts the yield of a hydrocracking aromatic kinetic scheme containing 15 pseudo-components as function of residence time.