Effect of hierarchical ZSM-5 zeolite support on direct transformation from syngas to aromatics over the iron-based catalyst

摘要

In this work, hierarchical ZSM-5 zeolites featured by different Si/Al ratio and mesoporosity were prepared via soft template. The hierarchical zeolites supported iron catalysts were prepared by incipient impregnation and their properties were studied by XRD, XRF, BET, SEM, TEM and NH3-TPD. The resultant catalysts were used to convert syngas into aromatics. The results indicated that zeolite with high acidity could increase the selectivity to aromatics in the oil product. By using low Si/Al ratio catalyst Fe-Z-50-5, 70.7% of selectivity to aromatics can be obtained in oil product. With the increase of mesoporosity, selectivity of C5+ oil product also increased. By adjusting silane addition, 23.2% selectivity of aromatics was obtained in hydrocarbon over Fe-Z-80-15 catalyst, which is the highest among all the same catalyst system under low H-2/CO syngas (H-2/CO = 1). However, hierarchical zeolite support with different Si/Al ratio and mesoporosity have little effect on the distribution of aromatic product.