In this study, a multiobjective optimization problem (MOOP) with two objec- tive functions (maximization of di-methyl-ether (DME) production rate and minimization of carbon dioxide release) was applied to the direct synthesis of DME from a natural gas-derived synthesis gas (syngas). Twelve degrees of free- dom were considered. The MOOP results suggest that the process with a maxi- mum DME production rate of 1686 kmol/hr releases 4788 kmol/hr CO2 while the CO2 release of the process with DME production rate of 1282 kmol/hr is 1761 kmol/hr. The higher the DME production rate, the lower net CO2 emis- sion to the air, natural gas consumption, and energy consumption per kg of the DME produced. In addition, the process with a higher DME production rate has a higher carbon efficiency and power production from the produced steam. The annual profit criteria of the overall process were used as a posterior preference index to select the best point from the resultant multiobjective opti- mization Pareto front. It was shown that the plant with the topmost DME pro- duction rate has the utmost annual profit compared to other Pareto optimum points. Lastly, the effect of degrees of freedom on the maximum DME produc- tion rate is discussed.

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