Hydrogenation of naphthalene over noble metal supported on mesoporous zeolite in the absence and presence of sulfur

Deep hydrogenation of aromatics is an important reaction in modern oil refinery. The key of an aromatic hydrogenation unit is high active, sulfur resistant hydrogenation catalyst. In this paper, the catalytic performance of a newly developed hydrogenation catalyst, platinum supported on mesoporous ZSM-5 (Pt/MZ-5), was tested in naphthalene (model compound of light cycle oil) hydrogenation. Pt/ZSM-5 and Pt/Alumina were used as reference. In some experiments, dibenzothiophene (DBT) was added to test the sulfur tolerance of catalysts. In the absence of DBT, Pt/MZ-5 and Pt/Alumina showed much higher hydrogenation activities and decalin selectivity than Pt/ZSM-5. The selectivity to decalin exceeds 97% over Pt/MZ-5 at temperature range between 523 and 573 K. Furthermore, Pt/MZ-5 shows better sulfur resistance than that of Pt/Alumina. In the presence of 3000 ppm dibenzothiophene, the selectivity of decalin over Pt/MZ-5 was only slightly dropped to 89.4% at 573 K, which is much higher than that of Pt/Al2O3 (51.4%). The excellent catalytic performance and sulfur tolerance of Pt/MZ-5 were attributed to the combination of high acidity and mesoporous structure in MZ-5.