Hydrophobically modified Pd membrane for the efficient purification of hydrogen in light alcohols steam reforming process

Abstract

The ability to selectively remove H2 from the product has made palladium (Pd) membrane reactor a good choice for steam reforming reaction. However, carbonaceous deposited on the surface of Pd membrane during reaction hindered its industrial application. In order to protect Pd membrane from being poisoned by water and light alcohols, a TS-1/Pd composite membrane was prepared by a facile one-step hydrothermal method combined with silane coupling treatment. The zeolite layer acted as a protective armor by keeping poisonous species away from the Pd bulk, and the silanization process increased the hydrophobicity by reducing the hydroxyl density on the surface of TS-1/Pd composite membrane. After 100 h’s exposure in the steam reforming condition, the percentage of carbon content was only 0.95% for the TS-1/Pd membrane, compared with 13.20% for the pure Pd membrane. The H2 permeability and H2/N2 selectivity of the TS-1/Pd remained constant, while that for pure Pd membrane fell by 50% and 80%, respectively. The significantly improved resistance to carbon deposition provides possibility for the large-scale application of Pd membrane reactor in hydrogen production via steam reforming.