The effect of steam on maximizing light olefin production by cracking of ethanol and oleic acid over mesoporous ZSM-5 catalysts

Abstract

Mesoporous ZSM-5 was used for catalytic cracking of ethanol and oleic acid for production of light olefins. The effects of cracking temperature and steam atmospheres on conversion, yield and selectivity were investigated. A steam atmosphere at an ethanol/water mass ratio of 1 : 3 achieved the highest light olefin yield (463.2 mL g⁻¹) and ethylene selectivity (77.5%) by cracking of ethanol at 400 °C, which were much higher than those obtained in N₂ (the highest light olefin yield was 318.3 mL g⁻¹ and the ethylene selectivity was 42.3%). Similarly, the steam atmosphere at a water flow rate of 1.0 mL min⁻¹ achieved the highest light olefin selectivity (69.8%) by cracking of oleic acid at 500 °C, which was two times higher than that obtained in N₂. Steam significantly improved the feed conversion and light olefin selectivity of products. The mesoporous ZSM-5 catalysts showed a superior hydrothermal stability and catalytic performance to the conventional microporous HZSM-5.