Phase separation behaviors and their relations with coke formation in thermal reaction systems of vacuum residua

A real-time optical microscope monitoring of the physical process of coke f ormation in the batch-type thermal reaction systems of three typical Chines e vacuum residua has evidenced that, as the residence time extends, there a ppear successively three kinds of neophases identified themselves by their morphology, onset point and bulk effect. The solubility test has demonstrat ed that all the three categories of neophases are of the same solubility cl ass. Additional proofs from the comprehensive time-sequential approach to t he thermal reaction process of vacuum residue and the morphological relatio ns disclosed by SEM between the neophases and coke have justified the heavy dependence of coke formation upon the neophases and their phase separation behaviors.