Production of benzene, toluene, and xylenes from natural gas via methanol: Process synthesis and global optimization

Abstract

A systematic global optimization‐based process synthesis framework is presented to determine the most profitable processes to produce aromatics from natural gas. Several novel, commercial, and/or competing technologies are modeled within the framework, including methanol‐to‐aromatics, toluene alkylation with methanol, selective toluene disproportionation, and toluene disproportionation and transalkylation with heavy aromatics, among others. We propose a stand‐alone chemicals facility: the main products are aromatics with allowable by‐products of gasoline, liquefied petroleum gas, and electricity. Several case studies are discussed that produce varying ratios of para‐, ortho‐, and meta‐xylene across multiple refinery capacities. The results indicate that utilizing natural gas for the production of aromatics is profitable with net present values as high as $3800 MM dollars and payback periods as low as 6 years. The required investment for these refineries represents as much as a 65% decrease compared to published estimates of similar coal‐based capacity plants. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1531–1556, 2016