Kaolin-based catalyst as a triglyceride FCC upgrading catalyst with high deoxygenation, mild cracking, and low dehydrogenation performances

Abstract

This work presents a cost-effective abundant kaolin-based cracking catalyst that has high deoxygenation, mild cracking, and low dehydrogenation performances for waste cooking oil (WCO) upgraded into organic liquid products (OLPs). Acid treated kaolin (ATK) exhibited high yield of 74.4% and high quality liquid products with high oxygen removal of 93.8% and low aromatic contents of 22.5%. The reference catalyst, a commercial petroleum catalyst (CC) could eliminate the most of oxygen (90.8%) but produced too many unexpected aromatics (55.8%). The density of weak Lewis acids was related to the deoxygenation capability. The density of Bronsted acids contributed to hydrogen transfer reactions. The total amount of Bronsted acids was correlated to cracking capability. The cracking by CC primarily followed carbonium ion reaction mechanism, whereas those by the kaolin-based catalysts complied more with free radical reaction mechanism. The deoxygenation active sites were characterized by CH3COOH-TPD for the first time.