OPERATION AND CONTROL OF A FLUID CATALYTIC CRACKER

Abstract

The cracking of methylcyclohexane (MCH) over silica-alumina catalyst and the regeneration of catalyst deactivated due to coking are applied to a fluid catalytic cracker system consisting of a cracker and a regenerator, and a system model is derived from the coke and heat balances. From numerical computations of this model, it is found that the system, although unstable, can be kept near the steady state point using both the feed temperature of MCH and the air flow rate in the regenerator as control variables. A control design to keep the conversion of MCH at a constant value is developed by means of a minimum time control theory. Further, effects of operating and reaction conditions on system stability are discussed.