Effects of zeolite morphologies on CO conversion to aromatics via a modified Fischer‐Tropsch synthesis pathway

Abstract

AbstractBACKGROUNDSyngas conversion to olefins via Fischer‐Tropsch Synthesis (FTs) route and then subsequently into aromatics (syngas−olefins−aromatics (SOA)) was considered a promising industrialization route due to its ability to match reaction temperatures between syngas to olefins (300–400 °C) and olefins to aromatics (300–500 °C). In this reaction route, the syngas to olefin process can be efficiently and easily realized by Fe‐based FTs catalysts. However, the aromatization process occurring over the zeolite catalyst was still considered a big challenge due to zeolites' complex topology, variable morphology, and elusive acidic properties.RESULTSA series of ZSM‐5 zeolites with different morphologies, including nano ellipsoid, nano cube, nano aggregate, nano bead, and nano pile were successfully synthesized . The effects of the ZSM‐5 zeolite's morphology and reaction temperature on the aromatics synthesis from syngas based on a modified FTs route were systematically studied.CONCLUSIONIn all the studied ZSM‐5 zeolites, the nano cube ZSM‐5 zeolite (Z5‐NC) zeolite had the best aromatization ability. The hybrid catalyst combination of FeMnK&Z5‐NC obtained the highest xylene selectivity of 12% (2.8% + 9.2%), and its total aromatics selectivity was also the highest (42.5%). The study on reaction temperature suggested that a higher reaction temperature (320–360 °C) could efficiently impede the formation of CO2. However, the selectivity of aromatics was restrained to around 44% at higher temperatures because a high temperature facilitated the hydrocracking of higher hydrocarbons, leading to the increase of the selectivity of lighter CH4 and paraffin. © 2022 Society of Chemical Industry (SCI).