CONTINUOUS-MIXTURE KINETICS OF COKE FORMATION FROM OLEFINIC OLIGOMERS

A model for interpreting the molecular-weight distributions is present ed for the olefinic oligomers and aromatic coke compounds that are exp erimentally observed in a catalyzed hexene isomerization process (the primary reaction). Reaction rate expressions for the secondary generat ion of hexene dimers, trimers and tetramers by irreversible reaction a re represented in mass balances for a stirred-tank reactor. Dehydrogen ation of the oligomers to form coke aromatics and their subsequent ads orption and desorption are included. A molecular-weight moment method allows solution of the model and computation of time dependence of mol ecular-weight distributions for all components. The model is consisten t with observations of decreased catalyst deactivation rates when coke desorption rates approach coke production rates. Catalyst activity ma intenance, which can occur under supercritical conditions, is also pre dicted by the model.