Gas separation: processes – Selective diffusion of gases – Selective diffusion of gases through substantially solid...
Reexamination Certificate
1999-06-18
2001-04-10
Spitzer, Robert H. (Department: 1724)
Gas separation: processes
Selective diffusion of gases
Selective diffusion of gases through substantially solid...
C096S011000, C055S524000, C055SDIG005
Reexamination Certificate
active
06214090
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to hydrogen-permeable membranes and in particular to a composite multilayer metal membrane for purification of hydrogen or its separation from a mixture of gases by diffusion through the membrane. Additionally, this invention relates to a method of separating hydrogen in a substantially pure form by use of the composite multilayer metal membrane that is permeable only to hydrogen.
BACKGROUND OF THE INVENTION
There are a variety of needs for essentially pure hydrogen. Included among these are fuel cells, membrane reactors and fuel reforming operations. As a result there is a strong interest in economical methods for hydrogen separation.
Composite multilayer metal membranes are known for the separation of hydrogen from gaseous mixtures. For example, U.S. Pat. No. 3,350,846 (Makrides et al.) describes separation of hydrogen by permeation through multilayer metal membranes including a Group VB metal sandwiched between two layers of palladium. In U.S. Pat. No. 5,149,420, Buxbaum et al. describe a method for plating palladium onto Group IVB or VB metals to form articles useful for hydrogen separation. U.S. Pat. No. 5,393,325 (Edlund) describes a composite hydrogen separation multilayer metal membrane, as does U.S. Pat. No. 5,738,708 (Peachey et al.).
In some applications of such composite multilayer metal membranes, improved operation at higher temperatures is desirable. Additionally, the catalytic metal layer can often be susceptible to poisoning from species in the feed stream such as, e.g., sulfur and chlorine. Accordingly, despite all of the previous work in the development of composite multilayer metal membranes for hydrogen separation, improvements have been continually sought to improve high temperature efficiency and to reduce susceptibility to poisoning.
It is an object of this invention to provide a composite multilayer metal membrane capable of separating hydrogen or its isotopes by selective diffusion through the membrane and more preferably essentially pure hydrogen or its isotopes, the composite multilayer metal membrane having improved high temperature efficiency.
It is another object of this invention to provide a composite multilayer metal membrane capable of separating hydrogen or its isotopes by selective diffusion through the membrane and more preferably essentially pure hydrogen or its isotopes, the composite multilayer metal membrane having reduced susceptibility to poisoning.
Still another object of the present invention is a process of forming a composite multilayer metal membrane for subsequent separation of essentially pure hydrogen by selective diffusion through the membrane.
SUMMARY OF THE INVENTION
To achieve the foregoing and other objects, and in accordance with the purposes of the present invention, as embodied and broadly described herein, a composite multilayer metal membrane is provided including a layer of a Group IVB or Group VB metal sandwiched between two layers of a Group VIIIB metal selected from the group consisting of palladium, platinum, nickel, rhodium, iridium, cobalt, and alloys thereof, and a non-continuous layer of a metal chalcogenide upon at least one layer of said Group VIIIB metal. In another embodiment of the present invention, an overlayer of a Group VIIIB metal selected from the group consisting of palladium, platinum, nickel, rhodium, iridium, cobalt, and alloys thereof is situated on composite metal membrane surfaces including the layer of a non-continuous layer of a metal chalcogenide.
The present invention further provides a process for the recovery of hydrogen from a gaseous mixture including contacting a hydrogen-containing gaseous mixture with a first side of a composite multilayer metal membrane including a layer of a Group IVB or Group VB metal sandwiched between two layers of a Group VIIIB metal selected from the group consisting of palladium, platinum, nickel, rhodium, iridium, cobalt, and alloys thereof and a non-continuous layer of a metal chalcogenide upon at least one layer of said Group VIIIB metal, and, separating hydrogen from a second side of said composite multilayer metal membrane. In another embodiment, an overlayer of a Group VIIIB metal selected from the group consisting of palladium, platinum, nickel, rhodium, iridium, cobalt, and alloys thereof is situated on composite metal membrane surfaces including the layer of a non-continuous layer of a metal chalcogenide.
The present invention still further provides a process of forming a composite metal membrane including cleaning a metal film selected from the group consisting of Group IVB metals and Group VB metals to remove surface oxides and surface imperfections from the metal film, depositing layers of a metal selected from the group consisting of palladium, platinum, nickel, rhodium, iridium, cobalt, and alloys thereof upon the cleaned surfaces of the Group IVB or Group VB metal film, and, depositing a non-continuous layer of a metal chalcogenide upon at least one layer of said Group VIIIB metal. In another embodiment of the present invention, an overlayer of a Group VIIIB metal selected from the group consisting of palladium, platinum, nickel, rhodium, iridium, cobalt, and alloys thereof is deposited over composite metal membrane surfaces including the layer of a non-continuous layer of a metal chalcogenide.
REFERENCES:
patent: 2958391 (1960-11-01), de Rosset
patent: 3350846 (1967-11-01), Makrides et al.
patent: 3428476 (1969-02-01), Langley et al.
patent: 5139541 (1992-08-01), Edlund
patent: 5217506 (1993-06-01), Edlund et al.
patent: 5259870 (1993-11-01), Edlund
patent: 5393325 (1995-02-01), Edlund
patent: 5498278 (1996-03-01), Edlund
patent: 5614001 (1997-03-01), Kosaka et al.
patent: 5645626 (1997-07-01), Edlund et al.
patent: 5738708 (1998-04-01), Peachy et al.
patent: 5782959 (1998-07-01), Yang et al.
patent: 1292025 (1972-10-01), None
Peachy et al., “Composite Pd/Ta Metal Membranes for Hydrogen Separation”, Journal of Membrane Science, vol. 11, pp. 123-133 (1996).
Ali et al., “Deactivation and Regeneration of Pd-Ag Membranes for Dehydrogenation Reaticons”, Journal of Membrane Science, vol. 89, pp. 171-184, (1998).
Ali et al., “Irreversible Poisoning of Pd-Ag Membranes”, Int. J. Hydrogen Energy, vol. 19, No. 11, pp. 877-880, (1994).
Shu et al., “Catalytic Palladium-Based Membrane Reactors: A Review”, The Canadian Journal of Chemical Engineering, vol. 69, pp. 1036-1060, (Oct. 1991).
Moss et al., “Multilayer Metal Membranes for Hydrogen Separation”, Int. J. Hydrogen Energy, vol. 23, No. 3, pp. 99-106, (1998).
Dye Robert C.
Snow Ronny C.
Cottrell Bruce H.
Spitzer Robert H.
The Regents of the University of California
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