Abstract The aim of this work is to develop and optimize an integrated process for natural gas plant in Egypt instead of flaring these gases and losing their revenues. The natural gas is sour wet feed gas containing mercury and some of volatile organic compounds with a capacity of around 21 million cubic feet per day. These impurities require sophisticated gas treatment processes that can handle and control the pollutants to acceptable limits. The design of new gas plant will be performed through firstly, the design methodology and cascade configuration of gas plant units based on feed gas composition. Secondly, integrated development and optimization of gas treatment process model is achieved using Aspen HYSYS simulation program. Thirdly, modeling of natural gas liquids extraction unit and fractionation train is conducted based on the required marketable products specifications. Finally, Aspen process economic analyzer program is used to calculate the expected capital expenditures of the plant. Optimizing the plant configuration accounts for best selection of treatment units and processing equipment, including mercury removal unit, sulfur recovery unit, BTEX recovery unit, etc. The preliminary capital expenditures of the gas conditioning and processing plant will be around 48 MUSD.