The optimization of an oil and gas separation plant operating revenue has been performed for different characteristic reservoir fluid types (gas condensate, volatile oil and black oil) using an evolutionary algorithm. A process simulation model mimicking a typical plant has been used as a black-box model and optimized with respect to nine design variables using the CMA-ES algorithm. The plant studied has three separation stages, including gas re-compression for each stage as well as a final gas boosting step before export. Each compression stage includes gas cooling and partial condensation