Molecular constitution, carbonization reactivity, and mesophase development from FCC decant oils

A study was carried out to investigate the effects of molecular composition and the reactivity of blending streams in coker feedstock on the mesophase development and needle coke texture. There was a significant variation among the degree of mesophase development in the sets of coker feedstock samples. Decant oil 02-1 and 02-4 had different major hydrocarbon distributions. There was much less pyrene and alkylated pyrenes present in DO02-1 than in DO02-4; normal alkanes concentration in DO02-1 was about two times higher than in DO02-4. Both coker feeds had higher concentration of phenanthrenes and pyrenes, and lower concentration of normal alkanes than their parent decant oils. The variations in hydrocarbon compositions showed similar trends as those noted for the corresponding decant oil samples. Intermediate (asphaltenes) and solid coke product yields from coking experiments (450°C) were presented. Differences in molecular composition of FCC decant oils and coker feeds derived from decant oils could be related to the differences obtained in the degree of mesophase development obtained upon carbonization of these materials. Concentration of n-alkanes and PAH distribution in the coker feeds affected coke formation rate and, thus, the extent mesophase development.