Ni and Sr modified ZSM-5 catalyst with enhanced catalytic activity for selective dehydration of bio-derived ethanol to ethylene

Abstract

Ni/Sr-ZSM-5 catalyst was synthesized with tuned acidity and improved hydrothermal stability desired for the dehydration of dilute ethanol. Operating conditions were established to maximize the ethylene selectivity from ethanol dehydration by controlling side reactions, using 6% aqueous ethanol as a model feedstock for fermenter broth. Detailed characterization data of the catalyst reveals that Ni in the catalyst is responsible for the enhanced, near quantitative ethylene selectivity at optimum reaction conditions (temperature of 250 °C, 9 h−1 WHSV), the Ni/Sr-ZSM-5 catalyst exhibited >96% conversion of ethanol with 95% yield of ethylene, facilitated by discouraging undesired side reactions of ethanol. The role of Sr is observed to improve the hydrothermal stability of the catalyst, allowing it to function even in the presence of 94% water in the feed at operated reaction conditions, as evidenced by its stable operation in the studied period of 30 h without significant loss in catalytic activity. The rate of ethylene formation with Ni/Sr-ZSM-5 was 5.33×10 −3 molgcat−1s−1, which is higher than neat H-ZSM-5. This study highlights the production of ethylene from low concentration feedstock using a catalyst with enhanced catalytic activity even in the presence of water in the feedstock.