Abstract: A multi-variable predictive controller is used to separate a multi-phase fluid on an offshore platform, thereby reducing condensable material in the gas product stream. A separation vessel containing a multi-phase fluid is provided, and pressure and temperature associated with the separation vessel are monitored. A Reid Vapor Pressure is calculated for the separation vessel based on the pressure and the temperature associated with the separation vessel. The multi-variable predictive controller actively controls the pressure and the temperature associated with the separation vessel such that the calculated Reid Vapor Pressure for the separation vessel is maintained within a predetermined amount of a reference Reid Vapor Pressure.