This paper covers an optimization study at Aramco's Khurais processing facility to maximize NGL yield and minimize H2S content through HYSYS simulation. Model validation and identifying the confidence level of the model (prior optimization) approach and results are covered along with the realized results of the optimized operating envelope in simulation compared to field trial results. The optimization approach focused on flashing more light ends due to a pressure drop in both the condensate feed drum and condensate stripper column while reducing NGL heating to maximize C3+ yield while maintain H2S below 30 PPMv. The identified optimized operating enveloped was implemented and benefits were realized. The main conclusions and realized benefits of adjusting the operating parameters to the optimized operating envelope includes maximizing NGL recovery in the facility by more than 900 BPD while maintaining quality parameters within limits, reduced the steam consumption by more than 150,000 lb/day and creating more tolerance to process upsets and normal fluctuations. The novelty of this paper is that it describes a process to define the confidence level of the model prior to commencing the optimization on a pre-existing model. In addition, it highlighted a simple approach to maximize C3+ recovery while minimizing H2S content and energy consumption, which creates room for optimization opportunities in any gas plant with no gas sweeting system.