Patent ID: 7662218

Claim:
A high-pressure hydrogen-purification membrane for hydrogen permeation at a pressure of 0.40 MPa or more, said membrane comprising a porous support substrate having a plurality of pores and a Pd alloy film joined to one surface of said porous support substrate, wherein: said membrane is configured to allow for permeation of hydrogen comprised in a reformed gas at a pressure of 0.40 MPa or more, each pore in said porous support substrate is configured to have a narrowest portion therein, between a thickness T of said porous support substrate, an opening diameter D 1 of each pore on a side joined to said Pd alloy film and an opening diameter D 2 of the pore on an opposite side, there are relations represented by 1.0≦D 1 /T≦5.0 and 1.0≦D 2 /T≦5.0, between the opening diameter D 1 of the pore on the side joined to said Pd alloy film, the opening diameter D 2 of the pore on the opposite side and an opening diameter D 3 of the narrowest portion of the pore, there are relations represented by D 3 /D 1 <0.8, D 3 /D 2 <0.9 and D 3 <250 μm, and a total opening area of the pores on the side joined to said Pd alloy film accounts for 20 to 80% of an area of said porous support substrate.