In-situ repair of composite palladium membranes with macro defects: A case study

A new method was developed for repairing Pd/Al₂O₃ membranes with macro defects without the need of disassembling the membrane from the module. In order to target and fill the membrane defect automatically with solid particles, a TiO₂ powder was firstly tested by flowing high-pressure nitrogen as a carrier gas, followed by a heat treatment. A filter cake was found on the membrane defect but still porous. A glass powder was selected instead of TiO₂, and the membrane defect was successfully sealed by glazing. The in-situ repair of a waste commercial Pd/Al₂O₃ membrane separator was carried out with the glass powder, and the hydrogen flux and H₂/N₂ selectivity of the membrane separator at 450 °C under 100 kPa reached 12.6 m³m⁻²h⁻¹ and 1600, respectively.