Effects of particle size on catalytic conversion of ethanol to propylene over H-ZSM-5 catalysts - Smaller is better

In this study, H-ZSM-5 catalysts with different particle sizes were prepared by adding different amount of water to the starting gel before crystallization. These H-ZSM-5 catalysts were characterized by scanning electron microscopy, N₂ adsorption/desorption measurements, X-ray fluorescence, X-ray diffraction, and temperature programmed desorption of ammonia. It was found that the olefin (ethylene, propylene and butene) yield decreased with the increase in the particle size of the catalysts. The paraffin (ethane, propane and butane) yield trended to increase with the increase of particle size. The C₅ + products yield increased considerably with the increase of particle size. The results implied that the formation of the C₅ + products and hydrogen was inhibited over the smaller particle size catalyst, furthermore the formation of paraffin decreased. So the propylene yield could be increased over smaller H-ZSM-5 catalyst.