Production of aromatics fuel additives from catalytic pyrolysis of cow manure over HZSM-5, HBeta, and HY zeolites

Abstract

Catalytic pyrolysis of cow manure (CM) over HZSM-5, HBeta, and HY zeolites was conducted for the first time to produce valuable biofuels such as benzene, toluene, ethylbenzene, xylene, and naphthalene (BTEXN). HZSM-5 revealed the highest BTEXN production efficiency, followed by HBeta and HY, due to high acidity and proper pore structure of the catalysts. Greatly increased production of BTEXN (Peak area; 203.7 × 107 counts) was achieved by applying HZSM-5 to the catalytic pyrolysis of CM accompanied by a decrease in oxygen-containing compounds (O-CCs) due to effective deoxygenation and aromatization. Increasing the acidity of HZSM-5 by decreasing the SiO2/Al2O3 ratio (SAR) from 280 to 30 also increased BTEXN production efficiency with a proportional decrease in O-CCs, suggesting the importance of catalyst acidity. Increasing the reaction temperature from 550 ℃ to 600 ℃ and increasing the catalyst-to-feedstock (C/F) ratio from 1:1 to 5:1 also increased production of BTEXN and further decreased O-CCs. Between in-situ and ex-situ catalytic pyrolysis, in-situ reaction was more effective for aromatics formation.