This paper addresses a problem regarding multivariable feedback control system for a binary fractionation column. First, a multivariable fractionation process is analyzed from input-output point of view using Simulink. The results of this analysis concluded that the commands of the process influence the compositions on the crossed channels too, so there is a need for a decoupler. Thus, the next step is the design of the decoupler for this process. The system consisting of the process and the decoupler is also analyzed through simulation. Finally, a multivariable control system with monovariable controllers is proposed.