Fluid catalytic cracking of vacuum residuum oil

摘要

A mixture of hydrocarbons consisting of gas oil and residual oil is catalytically cracked in the presence of a fluidized zeolite catalyst. The mixture of hydrocarbons is classified by boiling range as a 550 DEG -1000 DEG F. gas oil and a 1000+ DEG F. vacuum residuum. The gas oil is selectively cracked using a freshly regenerated fluid zeolite catalyst having less than 0.1 wt % residual carbon to give a high yield of desirable liquid hydrocarbon boiling from about 60 DEG -670 DEG F. The vacuum residuum is injected into the riser reactor at a point near the riser outlet to quench the cracking reactions in the gas oil. The vacuum residuum undergoes a small amount of reaction removing undesirable materials and yielding a liquid hydrocarbon boiling up to about 1000 DEG F. The amount of vacuum residuum cracking and overall yield of liquid hydrocarbons are controlled by downstream injection of vacuum residuum into the riser.