Methanol to gasoline process: Design and analysis of a structure with the minimum energy requirement and proposal of a novel integrated configuration to improve profitability

The primary challenge of the methanol to gasoline process, as a method for generating high-quality gasoline from a natural gas source, is the elevated cost of the gasoline product in competition with refinery-based alternatives. In this study, the process has been engineered for minimal energy consumption and evaluated through exergy, economic, exergoeconomic, and profitability analyses. Based on the results, a novel integrated configuration is proposed to improve the methanol to gasoline process profitability. The integrated process includes a natural gas liquefaction system based on the high-pressure exergy of the natural gas pipeline, a helium extraction and liquefaction, carbon dioxide capture and liquefaction, and a methanol to gasoline process. Results showed that the highest exergy destruction (almost 50 %) in the methanol to gasoline process belongs to the reactors, however, the exergy efficiency of the air coolers is the lowest (12 %). Also, most equipment has a low exergoeconomic factor (less than 15 %) meaning a higher share of exergy destruction in their economic performance. Air cooler AC-1 and reactors R-1 and R-2 displayed the highest total cost rate (more than 0.19 MM$/h). Total capital investment and annual operating cost were estimated at 147.36 MM$ and 7.51 MM$, respectively. Therefore, the process is unprofitable due to the current average price of methanol and gasoline. Results also showed the proposed process can produce various products with high profitability, a net present value of 28986.5 MM$, an internal rate of return of 30 %, and a payback period of 5.63 years regarding the current price of gasoline.