ZSM-5 crystals grown on the wall of a long tubular reactor as a structured catalyst for cracking of endothermic fuels

In situ growth of ZSM-5 crystals on the surface of Ni-based alloy supports by hydrothermal synthesis and their mechanical, structural stability were investigated. ZSM-5 crystals grown on the wall of a long (750 mm) tubular reactor with a small inner diameter (1 mm) was evaluated as a structured catalyst for cracking of n-heptane as a model endothermic fuel. The results have shown that the adhesion strength between ZSM-5 crystals and the support was strong enough to resist a heating/fast-cooling cycle (the sample was immersed into water immediately after being heated to be 750 °C). The crystalline structure of ZSM-5 crystals was also stable against the heating/fast-cooling cycle. The structured catalyst was shown to be catalytically active for cracking of n-heptane (LHSV = 200 h−1) at 700 °C. The formation rates of gaseous cracking products were 9.8 ml min−1 and 29.3 ml min−1 for the bare tubular reactor and the tubular reactor with ZSM-5 crystals grown on the wall, respectively. These structured catalysts show high promise for cracking of endothermic fuels at high temperatures.

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► ZSM-5/Ni-alloy composites were prepared by in situ hydrothermal synthesis.
► The composites were stable against a heating (750 °C)/fast-cooling cycle.
► ZSM-5 crystals were grown on the wall of a long tube to form a structured catalyst.
► The structured catalyst was catalytically active for cracking of endothermic fuels.