Catalytic upgrading of volatile from coal pyrolysis over faujasite zeolites

Catalytic upgrading of volatile from coal pyrolysis is a promising approach to convert heavy components to light aromatic hydrocarbons. In this work, four faujasite zeolites with different porosity and acidity, NaY, HY and two dealuminated Y zeolites including hydrothermal treatment Y (HTY) zeolite and hydrothermal treatment-acid leaching Y (HTY-AL) zeolite, were studied to upgrade coal pyrolysis volatile using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The results show that they can significantly improve the yield of light aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, and naphthalene (BTEXN). Compared to NaY and HY zeolite, HTY and HTY-AL zeolite have better catalytic performance for the formation of light aromatics, with the yield of BTEXN increases from 0.78 wt% (raw coal pyrolysis) to 3.63 wt% and 5.31 wt%, respectively. The polycyclic aromatics are cracked remarkably, especially for anthracene with cracking ratio around 60%. The excellent performance of dealuminated Y zeolites correlates directly with their wider range of pore size distribution and suitable acid properties. This work provides a feasible approach of optimizing the acid and textural properties of catalysts to upgrade coal pyrolysis volatile and obtain a high yield of BTEXN.