Coke Formation on KVO3−B2O3/SA5203 Catalysts in the Catalytic Pyrolysis of Naphtha

Abstract

Coke formation on KVO3−B2O3/SA5203 catalysts during naphtha pyrolysis in a fixed-bed reactor was studied. As the KVO3 loading increased, the amount of coke deposited on KVO3−B2O3/SA5203 decreased, but CO2 formation increased, indicating that KVO3 plays a key role in retarding coke accumulation but not in enhancing the product yields. The coke layers formed on the support and KVO3−B2O3/SA5203 were different in their properties. The coke layer formed on KVO3−B2O3/ SA5203 was free of soluble coke, which dissolves in the CH2Cl2 solution, and consisted of mainly insoluble coke; in contrast, the coke layer formed on the support consisted of both soluble and insoluble coke. The coke layer on KVO3−B2O3/SA5203 catalyst was porous, whereas that on SA5203 was nonporous. KVO3 on the catalyst apparently plays a key role in catalyzing the gasification of soluble coke to CO2.