RAPID

The current approach to p-xylene production includes an isomerization step that gives a nearly equilibrium distribution of mixed xylenes, followed by a separate step to recover p-xylene, then recycling of p-xylene depleted product for further isomerization. This project aims to develop and validate para-xylene ultra-selective zeolite membranes and integrate them with an appropriately designed isomerization catalyst in a membrane reactor to accomplish selective para-xylene production. A successful membrane reactor will increase the yield of para-xylene beyond the limits of equilibrium by selectively removing para-xylene from the reactor as it is produced. Increased productivity and reduced separation energy, capital intensity, and greenhouse gas emissions are the key drivers for developing such an approach. Recent breakthroughs introduced by the University of Minnesota for the synthesis of zeolite membranes using ultrathin zeolite crystals (2-dimensional zeolites and zeolite nanosheets) enabled unprecedented mixture separation factors for para-xylene over its isomers (up to 10,000). This ultra-selective performance has been validated by measurements at ExxonMobil Research and Engineering Company and membranes are currently being tested at temperatures, compositions and pressures relevant to membrane reactor operation.