Oxidative Coupling of Methane to Ethylene

This report details the design of a plant using the oxidative coupling of methane (OCM) to produce one billion pounds of ethylene and 534 million pounds of ethane per year. The ethylene and ethane produced are produced for sale to an olefins plant for further refining into polymers and plastics. The OCM process consumes a total feed of 9.10 billion pounds of methane and 4.62 billion pounds of oxygen per year. The methane and oxygen will be converted in four isothermal fixed-bed catalytic reactors operating at 1292°F and 96 psi. The catalyst is LiMgO in the form of 50 mm diameter spherical pellets. The remainder of the process encompasses an intricate separations train involving condensation, pressure swing adsorption, and cryogenic distillation. The unconverted methane is combusted to produce steam that is fed to a turbine to provide power to the plant with a residual 108 MW of electricity sent into the grid. The plant will be located in Baytown, Texas where access to feedstock and the olefin plants buying the products are easily attainable. After conducting an analysis of the sensitivity of the plant’s Internal Rate of Return with variable pricing and ethylene prices, it was determined that the plant is profitable exhibiting a Return on Investment of 25.61% and a Net Present Value of $517.2 million. Further research into catalysts increasing conversion of methane coupled with increased selectivity to C2 hydrocarbons will offer more attractive returns