Integrated process operations and optimization are highly demanded in petroleum industries due to increasing costs. One of the advances is monitoring the integrated process by using single modeling and optimizing platform. This paper presents iCON, PETRONAS owned process simulation software, to predict the optimum pressure set point for separator train and choke valves' opening, to maximize production in an existing facility. The source code developed was used to generate pressure and flow equation for each well to obtain material compositions for iCON model. Starting from current topside operating separator pressure, multiple case studies were run in iCON to produce production profiles at different operating pressures. The optimum pressure will be iteratively analyzed against the process constraint to locate the global optimum topside separator pressure set point. A single surface and sub-surface modeling platform ensures seamless data transfer, thermodynamic stability and efficient optimization iteration. The findings from this research are considered reaping the additional gas and oil production just by changing surface facilities separators set points and individual choke valve opening without violating process constraints. © Published under licence by IOP Publishing Ltd.