Maximization of a profit function related to a fluidized catalytic cracking unit model was carried out by Luus-Jaakola optimization procedure. A 7-dimensional search is carried out on a FCC unit described by 113 nonlinear algebraic equations and 9 differential equations. Despite the low sensitivity and the existence of several local optima, the global optimum was obtained with reasonable amount of computational effort. At the optimum, the profit function is 1 % higher than when the air blowers are constrained to operate at their maximum capacity.