Metallic nickel hollow fiber membranes for hydrogen separation at high temperatures

Metallic nickel dense hollow fiber membranes were fabricated by a combined spinning and high-temperature sintering technique. Hydrogen permeation through the nickel hollow fiber membranes was measured at high temperatures up to 1000 degrees C using H-2-containing gas mixtures fed on the shell side and N-2 as the sweep gas in the fiber lumen. The experimental results indicated the sintering should be carried out at around 1400 degrees C for 3 h, under a hydrogen-containing atmosphere so as to reach the required densification of the nickel hollow fiber membranes. Hydrogen permeation through the dense nickel hollow fiber membranes is controlled by H-atom diffusion through the membrane bulk, and can be well described by the Sieverts' equation with the activation energy of 51.07 kJ mol(-1). For the hollow fiber with wall thickness of 256 mu m, the hydrogen permeation flux value reached up to 7.66 x 10(-3) mol m(-2) s(-1) at 1000 degrees C with 100% H-2-permselectivity. The Ni hollow membrane exhibits high stability in CO2, CO or steam containing atmospheres, and demonstrates a potential use in hydrogen production by high temperature hydrocarbon reforming reactions. (C) 2016 Elsevier B.V. All rights reserved.