Design and economic analysis of industrial-scale methanol-to-olefins plants

Abstract

The production of ethylene and propylene, which are the building blocks of the petrochemical industry, from methanol is attractive because of the possibility of green methanol generation or the availability of inexpensive natural gas for methanol production. Based on the reactor performance of UOP/Hydro MTO (Methanol-to-olefins) technology, a base design and an alternative design of the overall process for an industrial-scale MTO plant are presented. The design scope includes the reaction and conditioning section, product separation and recovery section, ethylene and propylene refrigeration cycles, and cold-box. The alternative design differs from the base design by the use of a cold-box. The design employs driving force analysis, column targeting analysis, and pinch design method for distillation train determination, column improvement, and energy integration. Based on the current prices of methanol and olefins, both designs are profitable with IRR higher than 26%. The alternative design is superior to the base design in ethylene loss, energy consumption, exergy loss, and economic profit.