Amelioration of catalytic activity in steam catalytic cracking of vacuum residue with ZrO2-impregnated macro–mesoporous red mud

•ZrO2-impregnated macro–mesoporous red mud catalysts were successfully prepared.•ZrO2-impregnated macro–mesoporous red mud showed excellent catalytic activity.•The presence of a macroporous structure enhanced the catalytic activity.•The ZrO2(3)/MaRM-150 catalysts showed excellent regenerability.

ZrO2-impregnated macro–mesoporous red mud catalysts were successfully prepared for the catalytic cracking of vacuum residue (VR) in a steam atmosphere under a fixed-bed reaction condition at 500 °C for 2 h. Zirconia was homogeneously dispersed in the macro–mesoporous red mud, and the resulting catalyst had a high surface area, large pore volume, and highly ordered pore structure dimensions. When compared to a ZrO2-impregnated mesoporous red mud, the ZrO2-impregnated macro–mesoporous red mud catalysts exhibited better catalytic behavior for the steam catalytic cracking of VR. The presence of a macroporous structure ameliorated the catalytic activity due to improved accessibility to active hydrogenation sites and oxidative cracking, which in turn induced higher conversion values, a greater liquid yield, and a higher H/C ratio in the liquid product when compared to a ZrO2-impregnated mesoporous red mud catalyst. Furthermore, the ZrO2-impregnated macro–mesoporous red mud catalyst showed better regenerability due to both a large pore volume and the good stability of the pore structure.

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