In this paper, a supervisory control system for oxygen consumption optimization on a Syngas Manufacturing Process Plant is proposed. A grey-box multivariable parametric identification of the oxygen compressor system is first performed. Consequently, by means of dynamic simulations the structure of an optimal control system has been determined, also reflecting the implementation constraints linked with the use of a DCS. Finally, operating results of the system implemented on the real process are shown which confirmed the expected results obtained by simulations.