The use of new methods of control is one of greatest interest in the industry in recent years because it makes better use of resources and thus becomes an important factor in reducing costs associated with reprocessing and unnecessary use of raw materials. This research has the goal to evaluate the behavior of a fuzzy logic controller implemented on a combined mixer-reactor system. The fuzzy logic controller (FLC) is analyzed for the multivariable case in different operating conditions and its performance is compared with obtain through the implementation of a classical PID controller for deviations of 10% of the steady-state. The results show that the fuzzy logic controller (FLC) has a proper performance and improve in about 20% the classical control, this combined with the advantage of being able to include experience on process in actions taken by the strategy to keep the process in desired operation ranges.