A nonlinear control system was considered for a heterogeneous azeotropic distillation column that separates a three component mixture of water, n-butyl-acetate, and acetic acid. This system shows such complex dynamic behavior that it is difficult to operate it and to design its controller. In this study, we developed a dynamic simulator to understand and characteristics of the process. After considering the system's behavior by using the simulator, a control system was developed with exact input-output linearization. The control performance was examined when a step change happened in the feed composition and the feed flow rate. Compared with a multiloop control system, the proposed control system can quickly settle down at the setpoints with small fluctuations.