Process Simulation and Optimization of Dimethyl Ether (DME) Synthesis Utilizing Highly Contaminated Natural Gas as Feedstock

Natural gas with a high carbon dioxide (CO2) content presents significant operational and environmental challenges when used as a fuel. A high CO2 content lowers the calorific value of natural gas, reducing its fuel efficiency and increasing the risk of corrosion in pipelines and processing equipment. Consequently, such natural gas must be purified to reduce the CO2 content to acceptable levels before it can be effectively used as a fuel. Various technologies for natural gas purification are currently employed, primarily focusing on CO2 removal. This research explores an innovative approach where highly contaminated natural gas is utilized to synthesize hydrogen for subsequent methanol production. Methanol synthesis necessitates both hydrogen and CO2, integrating the use of by-products effectively in the production chain. Following the production of methanol, it is then converted into dimethyl ether (DME), a compound with considerable value as a clean fuel alternative due to its lower emissions when burnt. The open-source COCO simulator was used to model and simulate these processes, allowing for the creation of a detailed process flowsheet. The simulation covered four main stages: (1) purification of the natural gas to remove excess CO2, (2) production of hydrogen, (3) synthesis of methanol using the hydrogen and captured CO2, and (4) conversion of methanol to DME. This integrated approach mitigates the issues associated with high CO2 content in natural gas and leverages this component as a valuable feedstock, demonstrating a comprehensive use of all extracted compounds. The proposed process illustrates a promising route for utilizing highly contaminated natural gas, potentially transforming an environmental liability into valuable chemical commodities.