Techno-Economic Analysis for Ethylene and Oxygenates Products from the Oxidative Coupling of Methane Process

The interest in natural gas as an alternative feedstock for ethylene production stems mainly from its clean burning qualities, its domestic resource base, and its commercial availability. As the price of crude oil increases and an oil shortage looms, in the future, it becomes a concern for scientists trying to use natural gas as an alternative source of energy and as a feedstock in chemical industries. Methanol is one of the prime candidates for providing liquid fuels from natural gas as an alternative from traditional petroleum-based sources. In this work, a commercial-scale (210 tons/day) methanol plant, operating at steady state, which uses catalytic partial oxidation as a primary route (for synthesis gas production) from non-reacted methane coming from Oxidative Coupling of Methane (OCM) reaction has been designed. The main reason that motivates the realization of this work is to exploit the availability of unreacted methane, coming from the exit flue gas products of the OCM reactor, and thus, design an alternative process for oxygenates products, such as formaldehyde and methanol, that can make the process economically attractive and designed so as to be industrially implemented. The total project investment, based on total equipment cost, as well as variable and fixed operating costs, was developed based on mass and energy balance information taken from Aspen Process Economic Analyzer simulation results. The basis of the analysis is a world-scale conventional methanol plant that converts 368000 m(3) per day of methane into 210 tons per day of methanol and generates 76 tons/day of formaldehyde. Capital and operating costs are for a remote location where natural gas is available at (sic)12.60 per 1000 m(3). Payout time for this process, with an OCM plant, is around 8 years. This analysis suggests areas for research focus that might improve the profitability of natural gas conversion. Overall, the process described here appears to be feasible for the methanol production using non-reacted methane that comes from the OCM reaction process. This process can be implemented to enable optimum utilization of the methane gas based on market demand.