CA2323721A1 - Hydrogen separator - Google Patents
Hydrogen separator Download PDFInfo
- Publication number
- CA2323721A1 CA2323721A1 CA002323721A CA2323721A CA2323721A1 CA 2323721 A1 CA2323721 A1 CA 2323721A1 CA 002323721 A CA002323721 A CA 002323721A CA 2323721 A CA2323721 A CA 2323721A CA 2323721 A1 CA2323721 A1 CA 2323721A1
- Authority
- CA
- Canada
- Prior art keywords
- foil
- support structure
- separator
- hydrogen
- contact areas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
- B01D53/228—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion characterised by specific membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
- B01D63/02—Hollow fibre modules
- B01D63/026—Wafer type modules or flat-surface type modules
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
- B01D63/08—Flat membrane modules
- B01D63/087—Single membrane modules
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
- C01B3/50—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification
- C01B3/501—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by diffusion
- C01B3/503—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by diffusion characterised by the membrane
- C01B3/505—Membranes containing palladium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2313/00—Details relating to membrane modules or apparatus
- B01D2313/02—Specific tightening or locking mechanisms
- B01D2313/025—Specific membrane holders
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2313/00—Details relating to membrane modules or apparatus
- B01D2313/20—Specific housing
- B01D2313/208—Resilient or flexible housing walls, e.g. bags or foils
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Combustion & Propulsion (AREA)
- Inorganic Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Hydrogen, Water And Hydrids (AREA)
Abstract
A hydrogen separator that includes a thin hydrogen permeable foil having a thickness between 3 and 15 microns. The foil is bonded to a support structure.
The support structure is formed to have an undulating surface. The surface includes contact areas on which are secured the foil. The foil generally conforms to the undulating surface. The foil is only secured to the contact areas of the support structure; this enables the foil to move in three directions as it expands and contracts when exposed to the hydrogen source stream.
The contact areas are spaced relatively closely in comparison to the foil thickness and enable the thin foil to withstand high pressures.
The support structure is formed to have an undulating surface. The surface includes contact areas on which are secured the foil. The foil generally conforms to the undulating surface. The foil is only secured to the contact areas of the support structure; this enables the foil to move in three directions as it expands and contracts when exposed to the hydrogen source stream.
The contact areas are spaced relatively closely in comparison to the foil thickness and enable the thin foil to withstand high pressures.
Description
HYDROGEN SEPARATOR
Background of the Invention Field of the Invention The present invention is directed to a hydrogen separator and its method of manufacture. More specifically, the invention is directed to a hydrogen separator made from a thin foil secured to a support structure having an undulating surface.
Descriytion of Related Art Hydrogen separators are used in a number of commercial applications, including the refining of hydrocarbons, chemical processing, manufacture of hydrogenated oils as well as fuel cells. The separators work to refine a stream of relatively impure mixed gas containing less than 100 hydrogen (typically in the range of 20-80~) into very pure hydrogen (99.9990 . Most common hydrogen separators use a thick palladium, palladium alloy, or composite of a group Vb metal coated with palladium or a palladium alloy. These common foils usually have a thickness of greater than 25 microns. The foil is produced by rolling or pressing ingots into sequentially thinner sheets. The practical limit of the rolling process is currently 25 microns. This is considered thick foil. The thick foil is supported by a method that allows the feed side pressure to be higher than the permeate pressure since the 25 micron foil is not capable of withstanding high pressure alone. One example of this construction is illustrated in US patent No. 5645626.
In systems that use a thick palladium or palladium alloy, the performance is such that cost and size are major barriers to automotive/commercial separator design. For coated group Vb metals cost, S performance and size are acceptable, however the coated Group Vb metal substrates form hydrides that cause embrittlement resulting in unacceptable cycle life. An example of this construction is illustrated in US Patent No. 5738708. Furthermore, the coatings (5000 Angstroms palladium) will interdiffuse during even limited, <100 hours, operation at above 400° C causing failure of the catalytic dissociation of HZ into H at the surface.
The hydrogen disassociates on the foil surface and forms a metal hydride with the foil. The proton and electron IS from the hydrogen atom migrate through the foil and recombine on the opposite surface to form hydrogen gas.
This method is illustrated in U.S. Patent No. 5645626.
The foil generally expands up to 20~ when exposed to hydrogen while the underlying support material remains constant. Consequently, the foil must be made relatively thick to provide the durability needed for cyclic exposure to hydrogen gas. Unfortunately, the ability to pass hydrogen through a foil is directly proportional to the thickness of the foil while the cost is exponentially proportional in the case of palladium based foils. Increasing the foil thickness significantly reduces hydrogen permeability; also known as flux capacity. Increasing foil thickness also increases the cost of the separator. Increasing the temperature or pressure of the gas increases the flux capacity; however, the increased temperatures and pressures will damage thinner foils (<15 microns).
Background of the Invention Field of the Invention The present invention is directed to a hydrogen separator and its method of manufacture. More specifically, the invention is directed to a hydrogen separator made from a thin foil secured to a support structure having an undulating surface.
Descriytion of Related Art Hydrogen separators are used in a number of commercial applications, including the refining of hydrocarbons, chemical processing, manufacture of hydrogenated oils as well as fuel cells. The separators work to refine a stream of relatively impure mixed gas containing less than 100 hydrogen (typically in the range of 20-80~) into very pure hydrogen (99.9990 . Most common hydrogen separators use a thick palladium, palladium alloy, or composite of a group Vb metal coated with palladium or a palladium alloy. These common foils usually have a thickness of greater than 25 microns. The foil is produced by rolling or pressing ingots into sequentially thinner sheets. The practical limit of the rolling process is currently 25 microns. This is considered thick foil. The thick foil is supported by a method that allows the feed side pressure to be higher than the permeate pressure since the 25 micron foil is not capable of withstanding high pressure alone. One example of this construction is illustrated in US patent No. 5645626.
In systems that use a thick palladium or palladium alloy, the performance is such that cost and size are major barriers to automotive/commercial separator design. For coated group Vb metals cost, S performance and size are acceptable, however the coated Group Vb metal substrates form hydrides that cause embrittlement resulting in unacceptable cycle life. An example of this construction is illustrated in US Patent No. 5738708. Furthermore, the coatings (5000 Angstroms palladium) will interdiffuse during even limited, <100 hours, operation at above 400° C causing failure of the catalytic dissociation of HZ into H at the surface.
The hydrogen disassociates on the foil surface and forms a metal hydride with the foil. The proton and electron IS from the hydrogen atom migrate through the foil and recombine on the opposite surface to form hydrogen gas.
This method is illustrated in U.S. Patent No. 5645626.
The foil generally expands up to 20~ when exposed to hydrogen while the underlying support material remains constant. Consequently, the foil must be made relatively thick to provide the durability needed for cyclic exposure to hydrogen gas. Unfortunately, the ability to pass hydrogen through a foil is directly proportional to the thickness of the foil while the cost is exponentially proportional in the case of palladium based foils. Increasing the foil thickness significantly reduces hydrogen permeability; also known as flux capacity. Increasing foil thickness also increases the cost of the separator. Increasing the temperature or pressure of the gas increases the flux capacity; however, the increased temperatures and pressures will damage thinner foils (<15 microns).
Another type of hydrogen separator uses very thin layers of palladium between 0.1 and 0.5 microns thick. Because these very thin layers cannot be made self-supporting, they are plated onto a carrier. The carrier, generally vanadium, niobium, or tantalum, enables the disassociated hydrogen atom to pass through the separator. Another coating containing palladium, on the opposite surface of the separator, recombines the disassociated hydrogen atoms into gaseous hydrogen. An example of this construction is illustrated in U.S.
Patent Nos. 5738708 and 5149420.
This construction has the dual advantages of providing a large flux capacity because the palladium foil is very thin, and also relatively low cost because very little palladium is used in the coating material.
Unfortunately, the current base metallic (e. g. vanadium) carriers are susceptible to hydrogen embrittling. After several cycles, the vanadium~intermediate layer suffers internal fatigue and fractures which cause the separator to fail when cycled to operating conditions. Increased temperatures and gas pressures further exacerbate the embrittling process and reduce the life of the separator.
Another separator construction uses a thin coating of palladium on a ceramic substrate. The ceramic substrate is made to be porous to hydrogen and to receive the palladium coating. Because the coating is relatively thin, it has a high flux capacity and relatively low cost. Unfortunately, palladium coated ceramic substrates suffer from the same durability problems as the vanadium substrates. The ceramic substrate and palladium foil have vastly different coefficients of thermal expansion.
Patent Nos. 5738708 and 5149420.
This construction has the dual advantages of providing a large flux capacity because the palladium foil is very thin, and also relatively low cost because very little palladium is used in the coating material.
Unfortunately, the current base metallic (e. g. vanadium) carriers are susceptible to hydrogen embrittling. After several cycles, the vanadium~intermediate layer suffers internal fatigue and fractures which cause the separator to fail when cycled to operating conditions. Increased temperatures and gas pressures further exacerbate the embrittling process and reduce the life of the separator.
Another separator construction uses a thin coating of palladium on a ceramic substrate. The ceramic substrate is made to be porous to hydrogen and to receive the palladium coating. Because the coating is relatively thin, it has a high flux capacity and relatively low cost. Unfortunately, palladium coated ceramic substrates suffer from the same durability problems as the vanadium substrates. The ceramic substrate and palladium foil have vastly different coefficients of thermal expansion.
Also, the ceramic cannot be made to have a uniform porosity throughout the surface of the substrate. Those areas having relatively larger porosity create a void bridged by the palladium coating/foil. The ceramic expands up to 50 percent more than the palladium foil.
This often causes the foil to crack or tear in areas of coarser porosity. These small microtears in the palladium foil reduce the separator's ability to filter impurities from the source hydrogen stream.
In summary, the prior art systems for hydrogen separation are too costly and large, or not reliable due to cracking of the coated layers and/or substrates to be viable for automotive/commercial separation of large volumes of hydrogen.
The present invention attempts to provide a separator that has the high flux capacity and low cost of the thin foil devices together with the high temperature and high pressure durability of thick, non-embrittling foils. These and other disadvantages of the related art are overcome by the construction described herein.
Summary of the Invention The present invention is directed to a hydrogen separator that includes a thin hydrogen permeable foil having a thickness between 3 and 15 microns. The foil is bonded to a support structure. The support structure is formed to have an undulating surface. The surface includes contact areas on which are secured the foil.
The foil generally conforms to the undulating surface.
The foil is only secured to the contact areas of the support structure; this enables the foil to move in three directions as it expands and contracts when exposed to the hydrogen source stream. The contact areas are spaced relatively closely in comparison to the foil thickness and enable the thin foil to withstand high pressures.
The foil, once integrated with the support, becomes thick enough to then reliable secure it to mounting surfaces used in keeping separate the high and low pressure sides. If a thin foil were just rested on a support it would usually tear at this securing point if not fully integrated with the support.
The foil generally takes on a convoluted, repeatable shape, matching the undulating surface of the separator. Common separators include mesh or wire screens. The convoluted surface of the foil is generally between 20 and 50~ larger than the plan view area of the foil. Screens having a mesh between 200 and 635 squares per inch were found to be generally suitable for use as hydrogen separators.
The separators are manufactured by rolling a thin palladium containing foil between 3 and 15 microns.
The foil is then secured to the support structure. A
rolling or pressing process is found suitable to mechanically fasten the foil to the support structure along the contact areas. The foil generally conforms to the undulating surface of the screen. The screen imparts convolutions onto the foil and increases its surface area by 20~ to 50~. The foil remains secured to the screen without tearing or folding.
This often causes the foil to crack or tear in areas of coarser porosity. These small microtears in the palladium foil reduce the separator's ability to filter impurities from the source hydrogen stream.
In summary, the prior art systems for hydrogen separation are too costly and large, or not reliable due to cracking of the coated layers and/or substrates to be viable for automotive/commercial separation of large volumes of hydrogen.
The present invention attempts to provide a separator that has the high flux capacity and low cost of the thin foil devices together with the high temperature and high pressure durability of thick, non-embrittling foils. These and other disadvantages of the related art are overcome by the construction described herein.
Summary of the Invention The present invention is directed to a hydrogen separator that includes a thin hydrogen permeable foil having a thickness between 3 and 15 microns. The foil is bonded to a support structure. The support structure is formed to have an undulating surface. The surface includes contact areas on which are secured the foil.
The foil generally conforms to the undulating surface.
The foil is only secured to the contact areas of the support structure; this enables the foil to move in three directions as it expands and contracts when exposed to the hydrogen source stream. The contact areas are spaced relatively closely in comparison to the foil thickness and enable the thin foil to withstand high pressures.
The foil, once integrated with the support, becomes thick enough to then reliable secure it to mounting surfaces used in keeping separate the high and low pressure sides. If a thin foil were just rested on a support it would usually tear at this securing point if not fully integrated with the support.
The foil generally takes on a convoluted, repeatable shape, matching the undulating surface of the separator. Common separators include mesh or wire screens. The convoluted surface of the foil is generally between 20 and 50~ larger than the plan view area of the foil. Screens having a mesh between 200 and 635 squares per inch were found to be generally suitable for use as hydrogen separators.
The separators are manufactured by rolling a thin palladium containing foil between 3 and 15 microns.
The foil is then secured to the support structure. A
rolling or pressing process is found suitable to mechanically fasten the foil to the support structure along the contact areas. The foil generally conforms to the undulating surface of the screen. The screen imparts convolutions onto the foil and increases its surface area by 20~ to 50~. The foil remains secured to the screen without tearing or folding.
The use and other desired objects of the present invention will become more apparent in the course of the following detailed description and the appended claims. The invention may best be understood with reference to the accompanying drawings, wherein illustrative embodiments are shown.
Brief Description of the Drawings Figure 1 is a cross-sectional view of a separator assembly being joined in a press.
Figure 2 is a cross-sectional view of a separator using a standard mesh screen.
Figure 3 is a cross-sectional view of a separator assembly being joined by a pair of rollers.
Figure 4a are various views of a standard screen.
Figure 4b are various views of a "dutch weave"
screen.
Figure 5 is a graph of thermal expansion for palladium foil plotted against hydrogen flow.
Detailed Descriytion and Best Mode The invention will be illustrated and described as a hydrogen separator for use with a fuel cell. The invention is useful for any situation where a mixed gas stream containing hydrogen is separated into a relatively pure hydrogen stream. These and other devices and methods of operation are included within. the invention described herein. The following items are a word list of the components described in the drawings and are reproduced to aid in understanding the invention:
Brief Description of the Drawings Figure 1 is a cross-sectional view of a separator assembly being joined in a press.
Figure 2 is a cross-sectional view of a separator using a standard mesh screen.
Figure 3 is a cross-sectional view of a separator assembly being joined by a pair of rollers.
Figure 4a are various views of a standard screen.
Figure 4b are various views of a "dutch weave"
screen.
Figure 5 is a graph of thermal expansion for palladium foil plotted against hydrogen flow.
Detailed Descriytion and Best Mode The invention will be illustrated and described as a hydrogen separator for use with a fuel cell. The invention is useful for any situation where a mixed gas stream containing hydrogen is separated into a relatively pure hydrogen stream. These and other devices and methods of operation are included within. the invention described herein. The following items are a word list of the components described in the drawings and are reproduced to aid in understanding the invention:
word list 10,10' press 12,14 press surfaces 13,15 rollers 16 foil 18 support structure 20 contact areas 22 separator 24 foil surface 26 mesh openings 28 deformation amplitude 30 aluminum cloth The invention is designed to provide a low cost hydrogen separator that can withstand the rigors of automotive applications. The separator has an operating temperature range from between -40 to 600°C and is capable of withstanding pressures up to 25 bar. The invention utilizes a lower cost, thin palladium or palladium alloy foil as a separator material. The thin foil has the dual advantages of increasing the capacity of the separator while reducing the material cost. The foil and its method of manufacture are described in a commonly assigned patent application titled "METHOD OF
MANUFACTURING THIN METAL ALLOY FOILS", filed on even date herewith and incorporated herein by reference. The foil is imparted with a convoluted shape to increase the surface area and to provide a unique structure that is capable of expanding and contracting without tearing. A
support structure made of non-embrittling material imparts the convoluted shape to the foil and serves to support the foil during operation.
Illustrated in Figure 1 is a press 10 that is used to fasten the foil and support structure together.
The press 10 may be either hydraulically, pneumatically, or mechanically driven.
_7_ The press 10 includes two press surfaces 12, 14 that join the foil and substrate. A palladium foil 16 is placed between the press surfaces 12, 14. The foil is composed of palladium, palladium alloys that have been shown to not embrittle, or palladium coated non-embrittling metals such as a body centered cubic alloy.
The foil has a thickness of 3-15 microns, with the preferred thickness in the range of 5-7 microns.
Illustrated in Figure 2 is a roll press 10'. Rollers 13, 15 press the foil onto the support structure 18.
A support structure 18 is placed juxtaposed to the foil 16. The support structure has an undulating surface to provide a variety of contact areas 20 for attachment to the foil 16. The undulating surface of the foil forms a mechanical lock with the support. The contact areas 20 have a space therebetween so that the foil surface contacting adjacent contact areas 20 forms convolutions. A readily available material that has the needed undulating surface is a wire or mesh screen (wire cloth) having a mesh opening between 2 and 20 microns before compaction and 1 to 12 microns after compaction.
The screen may be fabricated from a material that is insensitive to hydrogen exposure such as stainless steel, hasteloy, monel, nickle, or other suitable material.
Stainless steel was found to be particularly well suited for use as a support structure because it was non-embrittling, readily available, high strength, and low cost. The support structure 18 can be coated with a 3o material to further isolate metallic interdiffusion between the screen and the foil such as alumina or titanium.
_g_ The foil 16 and the support structure 18 are placed between the press surfaces 12, 14 or rollers 13, 15 and the press 10 is moved to the closed position or the rollers 13, 15 are indexed. The press 10, 10' applies between 20 and 70 tons of force per square inch for a period of 1-5 seconds. The foil 16 is mechanically fastened to the support structure 18. When the pressure exceeds 60,000 psi, the palladium foil becomes coined and forms a mechanical bond to the support structure by interlocking with the screen gaps as they close during the deformation process.
The foil 16 and support structure 18 form a separator 22, as illustrated in Figure 3. The separator 22 includes the foil 16 and the support structure 18.
The foil 16 and the support structure 18 are mechanically fastened at the contact areas 20 by the foregoing pressing process. The pressing process also causes a deformation in the foil surface 24. The foil surface 24 is pushed into the mesh openings 26. The deformation amplitude 28 creates a series of convolutions on the foil surface 24. The foil surface 24 increases between 20 and 50~ as compared to the plan view area of the foil before the joining operation. The foil 16 is supported over the contact areas 20 to span the mesh openings. This span distance is approximately equal to the screen mesh size.
The screen mesh size is selected to support the foil 16 for a given operating pressure, temperature and foil thickness. Thinner foils and higher operating pressures or temperatures generally require a smaller mesh sizes.
The separator 22 is placed within a passage or chamber that receives a source gas stream that contains impure hydrogen. The source gas contacts the foil surface 24. Hydrogen within the source gas disassociates on the foil surface 24 and forms atomic hydrogen. The atomic hydrogen forms a metallic bond with the host ~Pd or Pd Alloy and passes through the foil 16 and reassociates on the opposite foil surface to form gaseous hydrogen.
The gaseous hydrogen passes freely through an underlying support structure 18. Separators of this construction are capable of purifying a source stream containing 15-99~ hydrogen to greater than 99.999 pure hydrogen.
The source stream is generally heated to between 200 and 600°C, preferably 450°C to facilitate catalysis and hydration of the hydrogen into the foil 16.
Both the hydration and elevated temperature cause the foil 16 to expand and elongate between 10 and 30~. This expansion and elongation causes the deformation amplitude 28 to increase. The expansion and elongation of the foil 16 is accommodated within the mesh opening 26. The contact areas 20 remain relatively constant. The foil 16 is free to expand and contract without tearing or folding.
A wide variety of screens having different mesh openings and mesh configurations exist. An example of this construction is illustrated in Figure 4a and b. The screen in Figure 4b uses a "dutch weave" construction where vertical threads interlock pairs of horizontal thread. This provides a coarser mesh having a rectangular opening.
Illustrated in Figure 5 is a graph of the hydrogen flux capacity vs. the palladium foil thickness.
Foils made by the present invention have a hydrogen flux capacity more than five times that of prior art thick foils.
While particular embodiments of the invention have been illustrated and described, it will be clear to those skilled in the art that various changes and modifications may be made thereto without departing from the scope of the invention and it is intended to cover in l0 the appended claims all such modifications and equivalents as fall within the true spirit and scope of the invention.
MANUFACTURING THIN METAL ALLOY FOILS", filed on even date herewith and incorporated herein by reference. The foil is imparted with a convoluted shape to increase the surface area and to provide a unique structure that is capable of expanding and contracting without tearing. A
support structure made of non-embrittling material imparts the convoluted shape to the foil and serves to support the foil during operation.
Illustrated in Figure 1 is a press 10 that is used to fasten the foil and support structure together.
The press 10 may be either hydraulically, pneumatically, or mechanically driven.
_7_ The press 10 includes two press surfaces 12, 14 that join the foil and substrate. A palladium foil 16 is placed between the press surfaces 12, 14. The foil is composed of palladium, palladium alloys that have been shown to not embrittle, or palladium coated non-embrittling metals such as a body centered cubic alloy.
The foil has a thickness of 3-15 microns, with the preferred thickness in the range of 5-7 microns.
Illustrated in Figure 2 is a roll press 10'. Rollers 13, 15 press the foil onto the support structure 18.
A support structure 18 is placed juxtaposed to the foil 16. The support structure has an undulating surface to provide a variety of contact areas 20 for attachment to the foil 16. The undulating surface of the foil forms a mechanical lock with the support. The contact areas 20 have a space therebetween so that the foil surface contacting adjacent contact areas 20 forms convolutions. A readily available material that has the needed undulating surface is a wire or mesh screen (wire cloth) having a mesh opening between 2 and 20 microns before compaction and 1 to 12 microns after compaction.
The screen may be fabricated from a material that is insensitive to hydrogen exposure such as stainless steel, hasteloy, monel, nickle, or other suitable material.
Stainless steel was found to be particularly well suited for use as a support structure because it was non-embrittling, readily available, high strength, and low cost. The support structure 18 can be coated with a 3o material to further isolate metallic interdiffusion between the screen and the foil such as alumina or titanium.
_g_ The foil 16 and the support structure 18 are placed between the press surfaces 12, 14 or rollers 13, 15 and the press 10 is moved to the closed position or the rollers 13, 15 are indexed. The press 10, 10' applies between 20 and 70 tons of force per square inch for a period of 1-5 seconds. The foil 16 is mechanically fastened to the support structure 18. When the pressure exceeds 60,000 psi, the palladium foil becomes coined and forms a mechanical bond to the support structure by interlocking with the screen gaps as they close during the deformation process.
The foil 16 and support structure 18 form a separator 22, as illustrated in Figure 3. The separator 22 includes the foil 16 and the support structure 18.
The foil 16 and the support structure 18 are mechanically fastened at the contact areas 20 by the foregoing pressing process. The pressing process also causes a deformation in the foil surface 24. The foil surface 24 is pushed into the mesh openings 26. The deformation amplitude 28 creates a series of convolutions on the foil surface 24. The foil surface 24 increases between 20 and 50~ as compared to the plan view area of the foil before the joining operation. The foil 16 is supported over the contact areas 20 to span the mesh openings. This span distance is approximately equal to the screen mesh size.
The screen mesh size is selected to support the foil 16 for a given operating pressure, temperature and foil thickness. Thinner foils and higher operating pressures or temperatures generally require a smaller mesh sizes.
The separator 22 is placed within a passage or chamber that receives a source gas stream that contains impure hydrogen. The source gas contacts the foil surface 24. Hydrogen within the source gas disassociates on the foil surface 24 and forms atomic hydrogen. The atomic hydrogen forms a metallic bond with the host ~Pd or Pd Alloy and passes through the foil 16 and reassociates on the opposite foil surface to form gaseous hydrogen.
The gaseous hydrogen passes freely through an underlying support structure 18. Separators of this construction are capable of purifying a source stream containing 15-99~ hydrogen to greater than 99.999 pure hydrogen.
The source stream is generally heated to between 200 and 600°C, preferably 450°C to facilitate catalysis and hydration of the hydrogen into the foil 16.
Both the hydration and elevated temperature cause the foil 16 to expand and elongate between 10 and 30~. This expansion and elongation causes the deformation amplitude 28 to increase. The expansion and elongation of the foil 16 is accommodated within the mesh opening 26. The contact areas 20 remain relatively constant. The foil 16 is free to expand and contract without tearing or folding.
A wide variety of screens having different mesh openings and mesh configurations exist. An example of this construction is illustrated in Figure 4a and b. The screen in Figure 4b uses a "dutch weave" construction where vertical threads interlock pairs of horizontal thread. This provides a coarser mesh having a rectangular opening.
Illustrated in Figure 5 is a graph of the hydrogen flux capacity vs. the palladium foil thickness.
Foils made by the present invention have a hydrogen flux capacity more than five times that of prior art thick foils.
While particular embodiments of the invention have been illustrated and described, it will be clear to those skilled in the art that various changes and modifications may be made thereto without departing from the scope of the invention and it is intended to cover in l0 the appended claims all such modifications and equivalents as fall within the true spirit and scope of the invention.
Claims (12)
1. A gas separator comprising:
a thin foil having a thickness between 3 and 15, and permeable to a selected gas ; and a support structure having an undulating surface, said surface having contact areas secured to and supporting said foil, whereby said foil conforms to said undulating surface.
a thin foil having a thickness between 3 and 15, and permeable to a selected gas ; and a support structure having an undulating surface, said surface having contact areas secured to and supporting said foil, whereby said foil conforms to said undulating surface.
2. The separator of claim 1, wherein said foil has a convoluted surface.
3. The separator of claim 2, wherein said foil convoluted surface area is between 20 and 50% greater than the plan view area of the foil.
4. The separator of claim 3, wherein said contact areas are spaced apart between 2 and 20 microns.
5. The separator of claim 1, wherein said foil contains between 10 and 100 palladium.
6. The separator of claim 1, wherein said support structure is a wire mesh screen.
7. The support structure of claim 6, wherein said screen has a mesh between 200 and 635 standard weave, and up to 1400 and 200 in alternate weaves.
8. The support structure of claim 1, wherein said support structure may have an interdiffusion barrier coating.
9. The support structure of claim 1, wherein said support structure is a stainless steel screen.
10. The separator of claim 1, wherein said selected gas is hydrogen.
11. A hydrogen separator for use with a fuel cell reformer separating a mixed gas source containing impure hydrogen comprising:
a thin hydrogen permeable foil containing palladium having a thickness between 3 and 15 microns;
and a wire mesh screen having a mesh opening between 2 and 20 microns, said screen having a having an undulating surface, said undulating surface having contact areas secured to and supporting said foil, whereby said foil forms a convoluted surface conforming to said undulating surface, said convoluted surface having a surface area 30% greater than the plan view area of the foil.
a thin hydrogen permeable foil containing palladium having a thickness between 3 and 15 microns;
and a wire mesh screen having a mesh opening between 2 and 20 microns, said screen having a having an undulating surface, said undulating surface having contact areas secured to and supporting said foil, whereby said foil forms a convoluted surface conforming to said undulating surface, said convoluted surface having a surface area 30% greater than the plan view area of the foil.
12. A method of producing a hydrogen separator, comprising the steps of:
providing a hydrogen permeable foil and a support structure immune to hydrogen embrittlement, said support structure having an undulating surface;
pressing together said foil and said support structure;
attaching said support structure to contact areas of said foil; and forming a convoluted surface of said foil.
providing a hydrogen permeable foil and a support structure immune to hydrogen embrittlement, said support structure having an undulating surface;
pressing together said foil and said support structure;
attaching said support structure to contact areas of said foil; and forming a convoluted surface of said foil.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US42046899A | 1999-10-19 | 1999-10-19 | |
| US09/420,468 | 1999-10-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2323721A1 true CA2323721A1 (en) | 2001-04-19 |
Family
ID=23666605
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002323721A Abandoned CA2323721A1 (en) | 1999-10-19 | 2000-10-18 | Hydrogen separator |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP2001162144A (en) |
| CA (1) | CA2323721A1 (en) |
| DE (1) | DE10044406A1 (en) |
| GB (1) | GB2355418A (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10122888A1 (en) * | 2001-05-11 | 2002-11-21 | Creavis Tech & Innovation Gmbh | Reforming fuel to hydrogen, employs electrically-heated composite membrane incorporating catalytic metallic layer separating hydrogen from reactor |
| DE10306235B4 (en) * | 2003-02-14 | 2005-02-03 | Daimlerchrysler Ag | Method and arrangement for resistance seam welding of a film and at least one film carrier of a fuel cell system |
| US7353982B2 (en) | 2003-11-25 | 2008-04-08 | Membrane Reactor Technologies Ltd. | Diffusion bonding for metallic membrane joining with metallic module |
| JP5395322B2 (en) | 2005-09-30 | 2014-01-22 | 日本精線株式会社 | Hydrogen separation element |
| US8961627B2 (en) | 2011-07-07 | 2015-02-24 | David J Edlund | Hydrogen generation assemblies and hydrogen purification devices |
| US9187324B2 (en) | 2012-08-30 | 2015-11-17 | Element 1 Corp. | Hydrogen generation assemblies and hydrogen purification devices |
| US10717040B2 (en) | 2012-08-30 | 2020-07-21 | Element 1 Corp. | Hydrogen purification devices |
| US20140065020A1 (en) | 2012-08-30 | 2014-03-06 | David J. Edlund | Hydrogen generation assemblies |
| US11738305B2 (en) | 2012-08-30 | 2023-08-29 | Element 1 Corp | Hydrogen purification devices |
| US10476093B2 (en) * | 2016-04-15 | 2019-11-12 | Chung-Hsin Electric & Machinery Mfg. Corp. | Membrane modules for hydrogen separation and fuel processors and fuel cell systems including the same |
| WO2019124576A1 (en) * | 2017-12-19 | 2019-06-27 | 정수환 | Rapid filtration apparatus using wire mesh screen thermocompressed stainless steel disc filter module |
| CN108525522B (en) * | 2018-06-20 | 2023-11-10 | 邢传宏 | Support element for flat membrane element and flat membrane element |
| US12187612B2 (en) | 2021-06-15 | 2025-01-07 | Element 1 Corp | Hydrogen generation assemblies |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1287584A (en) * | 1969-02-07 | 1972-08-31 | Johnson Matthey Co Ltd | Diffusion cell |
| DE3332348A1 (en) * | 1983-09-08 | 1985-04-04 | Kernforschungsanlage Jülich GmbH, 5170 Jülich | HYDROGEN PERMEATION WALL |
| DE3332346A1 (en) * | 1983-09-08 | 1985-04-04 | Kernforschungsanlage Jülich GmbH, 5170 Jülich | HYDROGEN PERMEATION WALL, METHOD FOR PRODUCING THE SAME AND THE USE THEREOF |
| US5498278A (en) * | 1990-08-10 | 1996-03-12 | Bend Research, Inc. | Composite hydrogen separation element and module |
| DE19983751B4 (en) * | 1998-11-10 | 2008-04-17 | ATI Properties, Inc., Gardena | Hydrogen Segregation membrane |
| DE19905638C1 (en) * | 1999-02-11 | 2000-06-08 | Dbb Fuel Cell Engines Gmbh | Hydrogen selectively permeable metal foil membrane, with support lamination, for supplying fuel cells has metal foil with woven or porous support layers on each side |
-
2000
- 2000-09-08 DE DE10044406A patent/DE10044406A1/en not_active Withdrawn
- 2000-10-05 GB GB0024423A patent/GB2355418A/en not_active Withdrawn
- 2000-10-18 CA CA002323721A patent/CA2323721A1/en not_active Abandoned
- 2000-10-19 JP JP2000319163A patent/JP2001162144A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JP2001162144A (en) | 2001-06-19 |
| DE10044406A1 (en) | 2001-07-05 |
| GB2355418A (en) | 2001-04-25 |
| GB0024423D0 (en) | 2000-11-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2323721A1 (en) | Hydrogen separator | |
| US5393325A (en) | Composite hydrogen separation metal membrane | |
| EP0470822B1 (en) | Hydrogen-permeable composite metal membrane | |
| US5645626A (en) | Composite hydrogen separation element and module | |
| JP5395322B2 (en) | Hydrogen separation element | |
| US4589891A (en) | Hydrogen permeatin membrane, process for its manufacture and use | |
| US8110022B2 (en) | Hydrogen purifier module and method for forming the same | |
| US7125440B2 (en) | Composite structure for high efficiency hydrogen separation and its associated methods of manufacture and use | |
| EP2147897B1 (en) | Hydrogen separator and method of operating hydrogen separator | |
| JPH11276866A (en) | Hydrogen permeable membrane and method for producing the same | |
| Klette et al. | Sputtering of very thin palladium-alloy hydrogen separation membranes | |
| US8226750B2 (en) | Hydrogen purifier module with membrane support | |
| JP2007007565A (en) | Hydrogen permeable membrane reinforcing structure and manufacturing method thereof | |
| JP2008155118A (en) | Composite membrane for separating hydrogen and module for separating hydrogen using this hydrogen permeable membrane | |
| US8002875B1 (en) | System and method for separating hydrogen gas from a mixed gas source using composite structure tubes | |
| TWI442966B (en) | Methods of fabricating porous media and inorganic selective film | |
| JP2004202479A (en) | Hydrogen separating permeation membrane, production method therefor, and separator for hydrogen production | |
| WO2005075060A1 (en) | Composite structure for high efficiency hydrogen separation and its associated methods of manufacture and use | |
| CN101543717B (en) | Hydrogen permeable modules and methods of use thereof | |
| JP3917709B2 (en) | Flat plate hydrogen separation membrane module | |
| US10189084B2 (en) | Method and system for fabrication of hydrogen-permeable membranes | |
| Lanning et al. | Un-supported palladium alloy membranes for the production of hydrogen | |
| JP2007245123A (en) | Hydrogen permeable membrane of composite multi-layer structure and its manufacturing method | |
| WO2024112793A2 (en) | Selective membranes and related methods | |
| JPH10297906A (en) | Hydrogen separation membrane and its manufacture |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |