COKE PRODUCTION FROM AN FCC-DECANT OIL - CHARACTERIZATION OF THE THERMAL-PROCESS

Detailed characterization of the thermal transformation of a decant oi l, obtained from a fluid catalytic cracking (FCC), in a closed system makes it possible to determine the mode and timing of coke production. A fast dismutation process into light and heavy liquid products is ob served, followed by slow production of coke with an activation energy of only 150 kJ mol-1. From elemental analysis, nuclear magnetic resona nce (n.m.r.) and mass spectra, dehydrogenation and condensation reacti ons are detected. These results are well modelled by the pyrolysis of a set of 1-aryl,2-phenylethylene compounds (aryl = two to four aromati c rings) under the same conditions. The phenanthrenic derivative prese nts a similar thermal profile towards coke production. The first steps are mainly dominated by non-radical processes such as electrocyclic r eactions.