Transalkylation of heavy aromatics for enhanced xylene production: Effect of metal type and concentration on the C9 conversion and xylene selectivity

Catalysts designated as catalyst-A, catalyst-B, and catalyst-C prepared and supplied by the Nippon Oil Research Institute Co Ltd were used in this study. The overall C₉ aromatics conversion activity and xylene selectivity for catalyst A was observed higher than catalysts B and C. The C₉ aromatics conversion and xylene selectivity increased with increase in reaction temperature and was further increased by optimizing the Mo contents. As the space velocity was increased keeping the reaction temperature constant, the percent concentration of C₆ to C₈ aromatics was decreased, and C₉ aromatics conversion was decreased while the xylene selectivity showed an increasing trend for both Mo-loaded and Re-loaded catalysts. Ethylbenzene slightly increased with increase in space velocity, but decreased with increase in reaction temperature. The gas components in the gas products of all three catalysts show the following trends of concentration: C2 > C3 > C4 > C1. The liquid components has xylene concentration in the following trend: m-xylene > p-xylene > o-xylene. C₉ aromatics conversion and xylene selectivity was higher with increasing Mo contents. However, too high metal contents on the catalyst had an adverse effect on the conversion and xylene selectivity. This is an abstract of a paper presented at the 15th Annual Saudi-Japanese Symposium: Catalysts in Petroleum Refining and Petrochemicals (Dhahran, Saudi Arabia 11/27-28/2005).