The Role and Potential of Attapulgite in Catalytic Pyrolysis of Refinery Waste Activated Sludge

ABSRACT Pyrolysis is a promising technology for the treatment of refinery waste activated sludge (rWAS). In this study, attapulgite as a natural clay was used to enhance the pyrolysis of rWAS. The yields, characteristics of pyrolytic products, pyrolytic kinetics and mechanisms were investigated. The attapulgite improved the conversion of rWAS into non-condensable gases and pyrolytic liquids. The bio-oil quality improved and the biochar yield reduced. The average activation energy of Stage I (230-400 °C) and Stage II (400-500 °C) decreased by 36.5% and 49.7%, respectively, compared to rWAS alone. Al2O3 and Fe2O3 in attapulgite enhanced the dealkylation reaction and cracking of C-C bonds. The content of the gasoline (