Hydrogen separation at low pressure using thin Pd-Au membranes

M.V. BLANCO; G. MEYER; A. BARUJ; A. TARDITI; L.M. CORNAGLIA

Zaragoza

Conferencia; 21st World Hydrogen Energy Conference (WHEC 2016); 2016

WHEC

The separation of hydrogen using Pd alloy membranes generates greatinterest due to the varied range of applications it can have on the industry.In this paper the results of the characterization of a Pd/Au membrane for theselective permeation of hydrogen from a gas mixture and its comparison with thecase of pure hydrogen are presented. A Pd/Au membrane of 10 microns thicknessdeposited on a porous stainless steel disk was used. In the membrane/substrateinterface a ZrO2 thin layer was deposited by dip coating method.This layer inhibits metal interdiffusion and creates a suitable surface for thedeposition of the Pd/Au layer [1]. The dependence of membrane permeated flowwith temperature (300° C - 500° C) and with a hydrogen pressure differencebetween both sides (up to 6 bar) was determined. The experimental resultsobtained by feeding the membrane with pure hydrogen were compared withmeasurements made by using a gas mixture feeding flow, H2:N2+ H2O in approximate ratio 49:1. Then, under a closed circulationsystem scheme, a reservoir was filled with the mentioned gas mixture to apressure of 2 bar, and the separation process was evaluated under a scenario ofdecreasing hydrogen partial pressure without altering the partial pressure ofimpurities. The study was repeated at different temperatures within the rangeindicated above, to a final pressure of 0.4 bar. The experimental results were used to obtain a phenomenologicalexpression that allows calculating the permeated hydrogen flow as a function oftemperature, pressure and impurity concentration in the gas mixture to be separated.