WO2001083086A1

WO2001083086A1 - Fluid separation assembly and fluid separation module

Info

Publication number: WO2001083086A1
Application number: PCT/US2001/012467
Authority: WO
Inventors: Chester B. Frost; Brett R. Krueger
Original assignee: Ati Properties, Inc.
Priority date: 2000-04-27
Filing date: 2001-04-12
Publication date: 2001-11-08
Also published as: US6419726B1; AU2001253592A1

Abstract

A fluid separation assembly (10) having a fluid permeable membrane (38 and 62) and a wire mesh membrane (18 and 28) adjacent the fluid permeable membrane (38 and 62), wherein the wire mesh membrane (18 and 28) supports the fluid permeable membrane (38 and 62) and is coated with an intermetallic diffusion barrier. The barrier may be a thin film containing at least one of a nitride, oxide, boride, silicide, carbide and aluminide. Several groups of multiple fluid separation assemblies (104) can be used in a module (85) to separate hydrogen from a gas mixture containing hydrogen.

Description

FLUID SEPARATION ASSEMBLY AND FLUID SEPARATION MODULE

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to apparatuses and methods for separation of a

desired fluid from a fluid mixture. More particularly, the present invention is

generally directed to a fluid separation module having several groups of multiple fluid

separation assemblies separated by plate members that allows the fluid mixture to pass

through the multiple fluid separation assemblies simultaneously. 2. Description of the Invention Background

Generally, when separating a gas from a mixture of gases by diffusion, the gas

mixture is typically brought into contact with a nonporous membrane which is

selectively permeable to the gas that is desired to be separated from the gas mixture.

The desired gas diffuses through the permeable membrane and is separated from the

other gas mixture. A pressure differential between opposite sides of the permeable

membrane is usually created such that the diffusion process proceeds more

effectively, wherein a higher partial pressure of the gas to be separated is maintained

on the gas mixture side of the permeable membrane. It is also desireable for the gas

mixture and the selectively permeable membrane to be maintained at elevated

temperatures to facilitate the separation of the desired gas from the gas mixture. This

type of process can be used to separate hydrogen from a gas mixture containing

hydrogen. Thus, in this application, the permeable membrane is permeable to

hydrogen and is commonly constructed from palladium or a palladium alloy. The

exposure to high temperatures and mechanical stresses created by the pressure

differential dictates that the permeable membrane be robust. The palladium and

palladium alloy of the permeable membrane is the single most expensive component

of the fluid separation device, so it is desirable to minimize the amount used in the

construction of the fluid separation assemblies while still providing fluid separation

assemblies that are strong enough to withstand the mechanical stresses and elevated

temperatures of typical operating conditions.

One type of conventional apparatus used for the separation of hydrogen from a

gas mixture employs several fluid separation assemblies in a fluid separation module, wherein the fluid separation assemblies are planar disks that are coaxially aligned and

stacked in a vertical direction. This type of configuration of the fluid separation

assemblies is commonly referred to as being a "series operation." The module has a

feed gas inlet, a permeate outlet and a discharge gas outlet. The path of the gas-

mixture containing hydrogen travels along the outer surface of each of the fluid

separation assemblies one at a time, wherein some of the hydrogen of the gas mixture

is free to enter the fluid separation assembly by the permeable membranes and is

directed to the permeate outlet and the remaining gas mixture serpentines through the

passageway contacting each of the remaining fluid separation assemblies one after the

other. As the gas mixture travels through the passageway, it contacts the outer

surfaces of several other fluid separation assemblies one at a time, wherein more of

the hydrogen remaining in the gas mixture permeates the permeable membranes and

follows the path resulting in this purified hydrogen passing to the permeate outlet.

The remainder of the hydrogen depleted gas mixture exits through the discharge gas

outlet located at the opposite end of the module after flowing over the entire stack of

fluid separation membrane assemblies. The disadvantage of this type of conventional

fluid separation assembly is that the fluid membrane assemblies located at the bottom

of the module are not fully utilized. The hydrogen content of the feed gas mixture is

depleted to the point where the driving force (i.e., the partial pressure of hydrogen)

required to diffuse hydrogen through the permeable membranes of the fluid separation

assemblies in the lower portion of the module is very low.

Another conventional fluid separation configuration recycles the hydrogen

depleted feed gas mixture. Recycling of the hydrogen depleted feed gas mixture back into the feed stream allows this type of fluid separation configuration to operate like a

fully mixed reactor by exposing all of the fluid separation assemblies to a hydrogen

feed gas mixture of identical composition. The disadvantage of this type of fluid

separation configuration is that it is expensive to recompress the hydrogen feed gas

mixture which is necessary to overcome the pressure losses as the hydrogen feed gas

mixture moves through the module.

Thus, the need exists for a method and apparatus for inexpensively and

effectively separating a desired fluid from a fluid mixture that can reliably withstand

high operating pressures and temperatures.

SUMMARY OF THE PRESENT INVENTION

The present invention provides a fluid separation module having groups of

multiple fluid separation assemblies that operate in parallel, creating a large

permeable membrane surface area for the fluid mixture to pass through. These groups

of multiple fluid separation assemblies can then be assembled in a module in varying

configurations or numbers depending on the specific application.

The present invention further provides a fluid separation assembly having a

thin design that reduces the weight and volume of the fluid separation assembly. This

thin design allows the subassemblies to be positioned in close proximity to each other

in the module, which increases the packing density of the permeable membrane

material (i.e., increases the permeable membrane surface area per unit of total volume

of the fluid separation module). The present invention provides the incorporation of turbulence inducing

mechanisms in the feed channel to further increase the turbulence and mixing of the

feed stream. These mechanisms may also be used as a support structure for catalytic

material. Having a specialized catalytic surface in close proximity to the permeable

membrane surface aids the kinetics of secondary chemical reactions to completion as

the hydrogen is removed from the feed stream through the permeable membrane.

The present invention provides several feed redistribution plates that direct the

feed flow through each group of multiple fluid separation assemblies that operate in

parallel thus, reducing the number of components of the fluid separation module.

The present invention provides a mechanical seal on each of the feed

redistribution plates to ensure that feed gases pass across the fluid separation

assemblies.

The present invention provides a fluid separation assembly having a fluid

permeable membrane and a wire mesh membrane support adjacent the fluid

permeable membrane, wherein the wire mesh membrane support has an intermetallic

diffusion bonding barrier.

The present invention further provides a method for separating a desired fluid

from a fluid mixture comprising providing a housing having a wall; providing a first

plurality of fluid separation assemblies positioned adjacent one another; providing a

second plurality of fluid separation assemblies positioned adjacent one another;

positioning a plurality of plates adjacent and between the first and second plurality of

fluid separation assemblies; forming a passageway defined by the plates and the

housing wall; passing fluid through the passageway and through the first plurality of fluid separation assemblies and through the second plurality of fluid separation

assemblies.

Other details, objects and advantages of the present invention will become

more apparent with the following description of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For the present invention to be readily understood and practiced, preferred

embodiments will be described in conjunction with the following figures wherein:

FIG. la is an isometric view of the fluid separation assembly of the present

invention as assembled;

FIG. lb is a top plan view of the fluid separation assembly shown in FIG. la;

FIG. 2 is an exploded isometric view of the fluid separation assembly of the

present invention shown in FIG. la;

FIG. 3 is an exploded isometric view of the female permeable membrane

subassembly of the present invention shown in FIG. la;

FIG. 4 is an exploded isometric view of the male permeable membrane

subassembly of the present invention shown in FIG. la;

FIG. 5 is a sectional view of the fluid separation assemblies of the present

invention shown in FIG. lb and taken along line 5-5;

FIG. 6 is a sectional schematic view of a fluid separation module of the

present invention having several groups of multiple fluid separation assemblies;

FIG. 7 is an enlarged schematic view of section A of the module shown in

FIG. 6; FIG. 8 is an isometric view of a feed redistribution plate of the present

invention;

FIG. 9 is an isometric view of a turbulence screen of the present invention; and

FIG. 10 is a sectional view of multiple fluid separation assemblies and a

turbulence screen of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described below in terms of apparatuses and

methods for separation of hydrogen from a mixture of gases. It should be noted that

describing the present invention in terms of a hydrogen separation assembly is for

illustrative purposes and the advantages of the present invention may be realized using

other structures and technologies that have a need for such apparatuses and methods

for separation of a desired fluid from a fluid mixture containing the desired fluid.

It is to be further understood that the figures and descriptions of the present

invention have been simplified to illustrate elements that are relevant for a clear

understanding of the present invention, while eliminating, for purposes of clarity,

other elements and/or descriptions thereof found in a hydrogen separation assembly.

Those of ordinary skill in the art will recognize that other elements may be desirable

in order to implement the present invention. However, because such elements are

well known in the art, and because they do not facilitate a better understanding of the

present invention, a discussion of such elements is not provided herein.

FIGS, la, lb and 2 illustrate one embodiment of the fluid separation assembly

10 of the present invention, wherein FIG. 2 is an exploded view of the fluid separation assembly 10 shown in FIG. la. The fluid separation assembly 10 comprises first

membrane retainers 12, a female membrane subassembly 14, a first membrane gasket

16, a first wire mesh membrane support 18, second membrane retainers 20, a slotted

permeate plate 22, a permeate rim 24, a second wire mesh membrane support 28, a

second membrane gasket 30 and a male membrane subassembly 32. In one

embodiment, the first retainers 12 may be substantially flat members having four

sides wherein two opposing sides are linear and the other two opposing sides are

curvilinear such that the periphery corresponds to the peripheries of the female and

male membrane subassemblies 14 and 32 and the thickness of the first retainers 12 is

between approximately 0.001 inches and 0.060 inches. The first membrane retainers

12 have centrally disposed openings 13 and 35. The first membrane retainers 12 may

be made from Monel 400 (UNS N 04400); however, other materials that are

compatible with the welding process, discussed below, may also be used. It will also

be appreciated that the first retainers 12 may have other desired shapes and other

thicknesses than those illustrated without departing from the spirit and scope of the

present invention.

FIG. 3 is an exploded view of the female permeable membrane subassembly

14. In this embodiment, female membrane subassembly 14, comprises a female

gasket seat 36, a hydrogen permeable membrane 38, an inner diameter membrane

gasket 40 and a center support washer 42. In this embodiment, the female gasket seat

36 is a substantially flat ring member 44 having raised faces 46a and 46b extending

around the ring member 44 and a centrally disposed opening 45. The raised faces 46a

and 46b are sized and proportioned to form a channel 47 which may accept a gasket 115, discussed below in connection with FIGS. 6 - 9, such that when the gasket 115 is

compressed, it will not extrude and thus, it will be contained within the channel 47. It

will be appreciated that there may be other geometries of gasket seats specific to other

gasket configurations or materials that may be used without departing from the spirit

and the scope of the present invention. The female gasket seat 36 may be made from

Monel 400; however, other materials such as nickel, copper, nickel alloys, copper

alloys, or other alloys that provide for compatible fusion with the chosen permeable

membrane material during welding may be used.

In this embodiment, the hydrogen permeable membrane 38 is a substantially

planar member having two opposing sides 41 which are substantially linear, two other

opposing sides 43 that are curvilinear, opposing surfaces 48 and a centrally disposed

circular opening 50. The inner diameter membrane gasket 40 is a flat ring member

having a centrally disposed opening 51. The center support washer 42 is a flat ring

member having a centrally disposed opening 53. The inner diameter membrane

gasket 40 and the center support washer 42 may be made of Monel 400 (UNS N

04400); however, other materials such as nickel, copper, nickel alloys, copper alloys,

or other alloys that provide for compatible fusion with the chosen permeable

membrane material or alloy during welding may be used.

Referring back to FIG. 2, in this embodiment, the first and second membrane

gaskets 16 and 30 are each a substantially flat member having centrally-disposed

openings 55 and 57, respectively. Similar to the first retainers 12 and the hydrogen

permeable membrane 38, the first and second membrane gaskets 16 and 30 have four

sides, wherein two opposing sides are substantially linear and two other opposing sides are curvilinear. In this embodiment, the first and second membrane gaskets 16

and 30 may be made from Monel 400 alloy (UNS N 004400), nickel, copper, nickel

alloys, copper alloys or other precious alloys or other alloys compatible with the weld

that is used to join the components of the fluid separation assembly 10 and which is

discussed below. The first and second membrane gaskets 16 and 30 may have a

thickness of between approximately 0.0005 inches to 0.005 inches. However, other

gasket thicknesses could be employed.

Also in this embodiment, the first and second wire mesh membrane supports

18 and 28 are planar members having centrally disposed openings 52 and 54,

respectively. The wire mesh membrane supports 18 and 28 each have four sides,

wherein two opposing sides are linear and the other two opposing sides are

curvilinear. The wire mesh membrane supports 18 and 28 may be made from 316L

stainless steel alloy with a mesh count of between approximately 19 to 1,000 mesh per

inch, wherein the mesh count is chosen to be adequate to support the hydrogen

permeable membranes 38 and 62 (FIGS. 3 and 4). The style of woven mesh may

include a standard plain square weave, twill square weave, rectangular plain or twill

weave, or triangular plain or twill weave. One example of a mesh count that may be

used is 49 mesh per inch. The wire mesh membrane supports 18 and 28 may be made

of steel alloys, stainless steel alloys, nickel alloys or copper alloys. The wire mesh

may be coated with a thin film that prevents intermetallic diffusion bonding (i.e., an

intermetallic diffusion bonding barrier). The intermetallic diffusion bonding barrier

may be a thin film containing at least one of an oxide, a nitride, a boride, a suicide, a

carbide, or an aluminide and may be applied using a number of conventional methods, including but not limited to, physical vapor deposition (PVD), chemical vapor

disposition, and plasma enhanced vapor deposition. For example, the method of

reactive sputtering, a form of PVD, can be used to apply a thin oxide film to the wire

mesh membrane supports 18 and 28. A variety of oxides, nitrides, borides, silieides,

carbides and aluminides may also be used for the thin film as well as any thin films

that will be apparent to those of ordinary skill in the art. Using this form of PVD

results in a dense amorphous thin film having approximately the same mechanical

strength as the bulk thin film material.

Also in this embodiment, the second membrane retainers 20 each are a

substantially flat member. The second membrane retainers 20 have four sides,

wherein two opposing sides are substantially linear and the other two opposing sides

are curvilinear. One retainer 20 has a centrally disposed opening 59 and the other

retainer 20 has a centrally disposed opening 60. See FIG. 2. These retainers 20 may

be the same thickness as the first and second wire mesh membrane supports 18 and

28. The second membrane retainers 20 may be made from a material that is

compatible with the weld, discussed below, such as Monel 400 (UNS N 004400) and

nickel, copper, nickel alloys, copper alloys, precious metals or alloys, or other alloys

that provide for compatible fusion with the chosen membrane material or alloy during

welding may be used.

In this embodiment, the slotted permeate plate 22 is a steel plate having a

plurality of slots 56 extending radially and outwardly from a centrally disposed

opening 58 in the direction of the periphery of the slotted permeate plate 22. The

number of slots 56 in a slotted permeate plate 22 may range from approximately 10 to 72. However, other suitable slot densities may be employed. The permeate plate rim

24 is a substantially flat member having a centrally disposed opening 63 that receives

the slotted permeate plate 22, wherein the opening 63 of the inner periphery is larger

than the outer periphery of the slotted permeate plate 22 allowing for a gap at 63

between the slotted permeate plate 22 and the permeate plate rim 24. See FIG. 5. The

shape of the slotted permeate plate 22 is similar to the other components of the fluid

separation assembly in that it has four sides, wherein two opposing sides are

substantially linear and the other two opposing sides are curvilinear. The permeate

plate rim 24 is made from Monel 400 (UNS N 04400); however, other materials can

also be used such as nickel, copper, nickel alloys, copper alloys, precious metals or

alloys or other alloys that provide for compatible fusion with the chosen membrane

material or alloy during welding.

FIG. 4 is an exploded view of the male permeable membrane subassembly 32.

The male membrane subassembly 32 comprises a male gasket seat 61, a hydrogen

permeable membrane 62, an inner diameter membrane gasket 64, and a center support

washer 66. The hydrogen permeable membranes 38 and 62 may be made from at

least one hydrogen permeable metal or an alloy containing at least one hydrogen

permeable metal, preferably selected from the transition metals of groups VIIIA or IB

of the periodic table. The hydrogen permeable membrane 62, the inner diameter

membrane gasket 64, and the center support washer 66 are similar in structure to the

hydrogen permeable membrane 38, the inner diameter membrane gasket 40 and the

center support washer 42, respectively, discussed above in connection with FIG. 3.

The hydrogen permeable membrane 62 has a centrally disposed opening 81. The male gasket seat 61 is a substantially planar ring member 68 having a circular

protuberance 70 extending around a centrally disposed opening 72. In this

embodiment, the female gasket seat 36 and the male gasket seat 61 are made of a high

strength alloy material that is compatible with the weld such as Monel 400. The inner

diameter membrane gaskets 40 and 64 are made from the same materials as the first

and second outer diameter membrane gaskets 16 and 30, discussed above.

FIG. 5 is a cross-sectional view of the assembled fluid separation assembly 10

of the present invention. When assembling the components of the fluid separation

assembly 10 shown in FIGS. 2-4, the female membrane subassembly 14 and the male

membrane subassembly 32 are initially assembled. The female gasket seat 36 (FIG.

3), the permeable membrane 38, the inner diameter membrane gasket 40 and the

center support washer 42 are placed adjacent one another such that their central

disposed openings 45, 50, 51 and 53, respectively, are coaxially aligned and form a

portion of a conduit 80. A first weld 71 (FIG. 5) is placed at the openings thereof.

The first weld 71 takes the form of a weld bead creating a hermetic seal between the

female gasket seat 36, the permeable membrane 38, the inner diameter membrane

gasket 40 and the center support washer 42. The weld 71 can be effected by a number

of commercially available technologies, including but not limited to, laser, electron

beam, and tungsten inert gas (TIG) welding. Alternative joining technologies such as

brazing or soldering may also be employed with the desired result being a gas tight

bond between the gasket seat 36 and the permeable membrane 38. Likewise, the

components of the male membrane subassembly 32 (FIG. 4), which include the male

gasket seat 61, the permeable membrane 62, the inner diameter membrane gasket 64 and the center support washer 66 are also placed adjacent one another such that their

centrally disposed openings 72, 81, 83 and 85 are coaxially aligned with each other

forming another portion of conduit 80 and a second weld bead 73 (FIG. 5) is placed

around the circumference of the openings 72, 81, 83 and 85 thereof. As stated above,

the weld 73 can be effected by a number of commercially available joining

technologies, including but not limited to, laser, electron beam, and tungsten inert gas

(TIG) welding.

After the components of the female membrane subassembly 14 and the

components of the male membrane subassembly 32 have each been connected by the

welds 71 and 73, respectively, they are assembled with the other components

described above to form the fluid separation assembly 10. As shown in FIG. 2, the

first and second retainer members 12 and 20, the female and male membrane

subassemblies 14 and 32, the first and second outer diameter gaskets 16 and 30, the

first and second wire mesh membrane supports 18 and 28, the slotted permeate plate

22 and the permeate rim 24 are aligned such that their centrally disposed openings are

coaxially aligned and form conduit 80. As shown in FIG. 5, these components are

retained in that configuration by placing a weld 74 at the outer periphery of the first

and second retainer members 12 and 20, the female and male membrane

subassemblies 14 and 32, the first and second outer diameter membrane gaskets 16

and 30, and the permeate rim 24. Alternatively, these parts could be assembled such

that their centrally disposed openings are coaxially aligned, as shown in FIG. 5, and

connected to one another by performing a brazing or soldering operation at the outer

periphery of the first and second retainer members 12 and 20, the female and male membrane subassemblies 14 and 32, the first and second outer diameter membrane

gaskets 16 and 30 and the permeate rim 24. A space at 63 (FIG. 5) between the

slotted permeate plate 22 and the permeate rim 24 permits expansion and contraction

of the components of the fluid separation assembly 10 resulting from the change in

temperature. Assembled, the fluid separation assembly 10 may have a thickness

ranging from 0.010 inches to 0.125 inches, depending upon the thicknesses of the

components employed.

FIGS. 6 and 7 illustrate a fluid separation module 85 of the present invention

employing several groups of multiple fluid separation assemblies 10, wherein FIG. 7

is an enlarged section A of the module 85. For clarity, the number of fluid separation

assemblies 10 shown in FIG. 7 has been reduced from ten to four between each

successive redistribution plate 102a, 102b, and 102c. To more clearly represent the

assembly of the module 85, the fluid separation assemblies 10 are shown in FIG. 7

without the details shown in FIG. 5. The fluid separation module 85 substantially

comprises a housing 100, a plurality of feed redistribution plates 102a-102j, several

groups of multiple fluid separation assemblies 104a-104i, a plurality of turbulence

screens 106, a plurality of guide rods 109, and a compression mechanism 108. The

compression mechanism 108 comprises a compression cap 160, high temperature

belleville type springs 162 and a spring guide 164. These components of the

compression mechanism 108 are standard in the industry. The housing 100

substantially comprises a cylindrical body, a permeate end plug 112a, a feed end plug

112b, compressible gaskets 118a and 118b, a lock ring 116a, a lock ring 116b, a feed

gas inlet 91, a permeate outlet 90 and a discharge gas outlet 93. The housing 100 may be made of carbon, alloy, heat and corrosion resistant steels, such as stainless steel or

other alloys; however, a variety of metals may also be used, as will be apparent to one

of ordinary skill in the art. A variety of conventional module housings can also be

employed with the present invention.

FIG. 8 is an isometric view of a feed redistribution plate 102 of the present

invention. The feed redistribution plates 102 each have a curvilinear portion 140, a

substantially linear portion 142, a feed redistribution sealing ring 130, and a female

gasket member 132 and a male gasket 134 (not shown) which are welded to

redistribution plate 102. The feed redistribution sealing ring 130 fits inside the slot

136 and around the curvilinear portion 140 of the feed redistribution plate 102. The

male and female gasket members 134 and 132 may take the same form as the male

and female gasket members 61 and 36, shown in FIGS. 4 and 3, respectively. The

feed redistribution plate 102 also has holes 138 which serve as alignment holes for the

guide rods 109 such that the guide rods 109 are received therein to maintain the radial

orientation of the redistribution plates 102, and the fluid separation assemblies 10 in

the housing 100. The guide rods 109 may be sized and proportioned such that they

are received by recesses in the end plug 112a (FIG. 8). The feed redistribution plate

102 may be made from stainless alloy or other suitable high temperature material.

FIG. 9 is an isometric view of a turbulence screen 106 of the fluid separation

module 85 of the present invention; and FIG. 10 is a sectional view of multiple fluid

separation assemblies 10 and a turbulence screen 106 of the present invention. The

turbulence screen 106 has a centrally disposed opening 150 and four sides, wherein

two opposing sides 152 are substantially linear and the other two opposing sides 154 are curvilinear. The turbulence screen 106 is a plain woven screen with a thickness

substantially the same as the opening of the flow channel between fluid separation

assemblies is utilized. Conventional woven mesh may be used for the economic

manufacture of the turbulence screens 106, but other materials that promote

turbulence could also be selected, such as refractory or high temperature cloths, fibers,

mats, felts, or papers. Reticulated ceramics and other types of woven or mat type

metal materials (i.e., steel wool) would also serve as a suitable material for the

turbulence screen 106. These turbulence screens 106 also may be coated with

catalytic material to drive secondary chemical reactions to completion in close

proximity to the hydrogen permeable membrane surfaces, without actually contacting

the permeable membrane surfaces 48 and 62 and causing damage. The selection of

the material and construction should be compatible with the type of catalytic material

employed. Catalytic materials may be chosen from a variety of commercially

available catalysts. The choice of catalytic material is dependent upon the required

operating parameters of the reaction (i.e., pressure, temperature, type and

concentration of the constituents in the feed stream) as well as the desired reaction.

The catalytic materials could be applied directly to the turbulence screen 106, or

indirectly using an intermediate coating material to improve adhesion and prevent

spalling of the catalytic material during operation of the module 85. The main criteria

for the selection of the material of the turbulence screen 106 is that the material be

thermally stable and rigid enough so that it will not deform and possibly damage the

permeable membranes 48 and 62. Referring back to FIGS. 6 and 7, when assembling the fluid separation module

85, the end plug 112a may be welded to the female gasket seat 114. Suitable

plumbing fittings (not shown), such as a compression or face seal type, may be

welded to the permeate port outlet 90 and discharge outlet port 93. A pliable high-

temperature gasket 118a is then installed onto the end plug 112a. The gasket 118a

may be a molded or pressed unitary flat wound material, a rectangular or square cross-

sectional woven or non-woven packing material, or a multiple cut ring of sheet-type

gasket material that is fitted onto the shoulder of the end plug 112a to create a

compression-type seal. Other types of mechanical seals, such as metal o-rings, metal

c-section seals, or soft metal seals, may also be used.

After the gasket 118a is in place, the end plug 112a is inserted into the module

body 110 and a threaded lock ring 116a is screwed into the end of the module housing

100. The module 85 is then placed into a press (not shown) and a mechanical force is

applied to the end plug 112a forcing it down against the lock ring 116a thus,

compressing the gasket 118a and forcing the gasket 118a in an outward radial

direction against the wall 110 of the module 85, creating a seal.

One feed redistribution plate 102a is inserted into the housing 100 adjacent the

female seat 114. The sealing ring 130 of the feed redistribution plate 102a is

compressed and forms a fluid tight seal with the housing 100. The grooves 136 cut

into the outer periphery of the redistribution plates 102 allow the sealing rings 130 to

be compressed. Once the redistribution plates 102 are lowered into the housing 100,

the compression on the sealing rings 130 are released, allowing them to contact the

wall 110 of the housing 100. The male gasket seat 134 on the underneath sides of the redistribution plates 102 are in contact with a fibrous gasket 115 (FIG. 7) that is

received within the female gasket seat 114. It will be appreciated that other

mechanical seals employing different geometries and different materials may be used

to effect a fluid-tight seal.

After the redistribution plate 102a is in place, a plurality of the fluid separation

assemblies 104a and turbulence screens 106 positioned between each of the fluid

separation assemblies 104a may then be assembled into the module 85. The guide

rods 109 are inserted into the holes 138 of the redistribution plate 102a. The centrally

disposed openings of each of the turbulence screens 106, the fluid separation

assemblies 10 and the feed redistribution plates 102 are coaxially aligned. The

turbulence screens 106 are added between each pair of fluid separation assemblies 10

to promote turbulent flow of the feed gases and insure that hydrogen rich feed gas is

continuously fed to the membrane surface. The turbulence screens 106, shown in

FIGS. 6, 7 and 9, contact the planar surfaces of the female gasket seat 44 (FIG. 5) and

the male gasket seat 68 when the module 85 (FIG. 6) is constructed. The turbulence

screens 106 are held in place by the first membrane retainers 12 of the fluid separation

assemblies 10 that are adjacent to each turbulence screens 106. A turbulence screen

106 is positioned between fluid separation assemblies 10, as shown in FIG. 10, when

the fluid separation assemblies 10 are stacked adjacent to one another to create groups

of multiple fluid separation assemblies 104a-104i (FIGS. 6 and 7).

The turbulence screens 106 also serve as a substrate for the application of

reaction catalysts that will prompt a secondary reaction adjacent to the permeable

membrane surfaces 48 and 62. One example of a catalytic material that may be used for methanol steam reforming or water-gas shift reactions is a material comprised of

Cu/ZnO/A1203, wherein the desired reaction to take place would be dependent upon

the operating parameters employed. When a hydrogen producing reaction is carried

out in this manner, the reaction kinetics are driven to completion by the continuous

removal of hydrogen from the feed stream by the hydrogen permeable membranes 48

and 62. An example of this type of reaction is the water-gas shift reaction, which is

denoted as:

H₂Ovapor + CO -» H₂ +CO₂

As the water vapor and carbon monoxide react to form hydrogen and carbon dioxide

in the presence of a suitable catalyst, hydrogen is continually being removed by the

hydrogen permeable membranes 48 and 62 thus, allowing a substantially complete

reaction. This type of reaction is common in hydrogen rich reformate streams, where

both water vapor and carbon monoxide are present. Catalytic materials may be

chosen from a variety of commercially developed catalysts, wherein the selection of

the catalytic material would be dependent upon the required operating parameters of

the reaction (i.e., pressure, temperature, type and concentration of the constituents in

the feed stream) as well as the desired reaction to take place. The catalytic materials

may be applied directly to the turbulence screen 106, or indirectly using an

intermediate coating material to improve adhesion and prevent spalling of the

catalytic material during operation.

The redistribution plates 102 are positioned on the female and male gasket

seats 36 and 61 in such a manner that they are positioned equidistant from the planar

surface of the permeable membrane assemblies 14 and 32 in successive fluid separation assemblies 10. The redistribution plates 102 are not fixedly connected to

the gasket seats 36 and 61, but rather are received by the channel 47 of the female

gasket seat 36 and the raised face 70 of the male gasket seat 61. There is sufficient

clearance between slot 136 and the sealing ring 130 of the redistribution plate 102

such that the redistribution plate 102 and the fluid separation assemblies 10 are

positioned inside the wall 110 of the housing 100 independently of the position of the

fluid separation assemblies 10. Each redistribution plate 102 has opening 89 therein.

Several groups of multiple fluid separation assemblies 104b-104i (FIG. 6) are

stacked within the module 85, wherein the feed redistribution plates 102b- 102j

separate the groups of fluid separation assemblies 104b-104i and turbulence screens

106 separate successive fluid separation assemblies 10. The fluid separation

assemblies 10 are aligned one with the other such that each of the conduits 80 (FIG. 5)

of the fluid separation assemblies 10 form a portion of channel 180. The assembly of

the module 85 continues by alternatively stacking a gasket 115, multiple fluid

separation assemblies 104 having turbulence screens 106 positioned between

successive fluid separation assemblies 10, and feed redistribution plates 102 until the

desired number of groups of multiple fluid separation assemblies 104 have been

stacked in the module 85. Please note that the redistribution plate 102b is assembled

in the same way as the redistribution plate 102a, with the exception that it is rotated

180 degrees relative to the first redistribution plate 102a. This alternating orientation

of the redistribution plates 102 along the stack of fluid separation assemblies 104a-

104i creates a fluid passageway C (FIG. 7) that directs the feed gas over each group of

fluid separation assemblies 10. It should also be noted that the number of fluid separation assemblies 10 in the multiple fluid separation assemblies 104a-104i may be

assembled in different quantities. In this embodiment, equal numbers of fluid

separation assemblies 10 comprising the multiple fluid separation assemblies 104

have been placed between each successive redistribution plate 102 for purposes of

illustration only. The number of fluid separation assemblies 10 between each

successive redistribution plate 102 may be reduced or increased to optimize the

performance of the fluid separation assemblies 10 at each successive stage in the

module 85. Altering the number of fluid separation assemblies 10, and thus the total

permeable membrane area between each successive redistribution plate 102, allows

the overall performance of the hydrogen separation module 85 to be maximized with

respect to the total permeable membrane area required for a given fluid separation

application. For example, a larger number of fluid separation assemblies 10 may be

positioned together at the feed end of the module 85, where the feed stock gas is

highest in hydrogen content and a reduced number of fluid separation assemblies 10

may be positioned at the raffinate end of the module 85, where the hydrogen depleted

feed gas exits.

When the last redistribution plate 102j is assembled in the module 85, the

compression mechanism 108 is placed on the redistribution plate 102j. The belleville

springs 162 are sized such that at full compression, supplies a compressive load

sufficient to maintain a positive sealing force on the gaskets 115 positioned between

the fluid separation assembles 104a-104i in the module 85. When the gaskets 115 are

compressed, they also provide a small amount of give to compensate for the different

coefficients of thermal expansion inherent to the different materials used in the module 85. As the module 85 thermally cycles between ambient and operating

temperatures, the components within the module 85 are able to expand and contract.

This small amount of give also helps compensate for any additional compression of

the gaskets 118a and 118b that may occur over time.

With the compression mechanism 108 in place, the end plug 112b is fitted

with a gasket 118b identical to the gasket 118a, and is lowered into the module 85. A

suitable plumbing fitting (not shown), such as a compression or face seal type fitting

is welded into the inlet port 91. The lock ring 116b is then screwed into the module

85 to a point where it is flush with the end of the housing 100. A setscrew 175 is

inserted into the threaded compression screw hole 172. As this setscrew 175 is

tightened, it contacts the compression cap 160 and forces the end plug 112b upwards

against the lock ring 116b. This results in the gasket 118b being forced outwardly in a

radial direction against the wall 110, thus creating a fluid-tight seal. At the same time

that the end plug 112b is being forced upwards, the setscrew 175 is compressing the

belleville springs 162 and thus, maintaining a compressive force on the gaskets 1 15

within the module 85. After the setscrew 175 has been tightened to the required

torque necessary for fully compressing the belleville springs 162, a sealing gasket (not

shown) is placed in the recess surrounding the threaded screw hole 172. The cap 170

is then screwed into the hole 172 and tightened to create a positive seal with the

sealing gasket positioned in the recess surrounding the hole 172 and the end plug

112b.

During operation, the hydrogen rich feed gas is admitted into the inlet port 91

and travels in a serpentine fashion through passageway C in the module 85 where the feed gas encounters multiple fluid separation assemblies 104a- 104i. Specifically,

pure hydrogen is first diffused through the permeable membrane of each fluid

separation assembly 10 comprising multiple fluid separation assemblies 104i and is

collected in a central permeate channel 180. The permeate hydrogen exits the module

85 through the permeate outlet 90, while the hydrogen depleted mixture exits through

the discharge outlet 93. Referring to FIG.5, when separating the hydrogen from the

feed gas that includes hydrogen, the feed gas is directed towards the permeable

membranes 38 and 62 of the female membrane subassembly 14 and the male

membrane subassembly 32, respectively, in the directions D and E. When the feed

gas containing hydrogen contacts the hydrogen permeable membranes 38 and 62, the

hydrogen permeates through the permeable membranes 38 and 62, passes through the

first and second wire mesh membrane supports 18 and 28 and enters the slotted

permeate plate 22 where the hydrogen enters slots 56 and is directed toward the

central axis H by the passageways formed by the slots 56. The central openings of the

components of the fluid separation assembly 10 form the conduit 80, which forms a

portion of the channel 180 such that the purified hydrogen is collected and transported

to the permeate outlet 90. The conduit 80 may have a diameter of between

approximately 0.25 inches and 1 inch. The diameter is determined by the components

of the fluid separation assembly 10 and by the desire that the hydrogen flow be

substantially unimpeded. The non-hydrogen gases in the gas mixture are prevented

from entering the fluid separation assembly 10 by the fluid permeable membranes 38

and 62. The remainder of the hydrogen depleted feed gas is directed around the

exterior of the fluid separation assembly 10 and continues along the passageway C to the next set of multiple fluid separation assemblies 104h, 104g, 104f, 104e, 104d,

104c, 104b and 104a.

Although the present invention has been described in conjunction with the

above described embodiment thereof, it is expected that many modifications and

variations will be developed. This disclosure and the following claims are intended to

cover all such modifications and variations.

Claims

What is claimed is:

1. A fluid separation module, comprising:

a housing having a wall;

a first plurality of fluid separation assemblies within said housing, each of said

first plurality of fluid separation assemblies are adjacent one another;

a second plurality of fluid separation assemblies within said housing, each of said

second plurality of fluid separation assemblies are adjacent one another;

a plurality of plates within said housing, said plurality of plates positioned

between and separating said adjacent first plurality of fluid separation assemblies

members from said adjacent second plurality of fluid separation assemblies; and

a fluid passageway defined by said plurality of plates and said housing wall.

2. The fluid separation module according to claim 1, wherein each of said first and

second plurality of fluid separation assemblies comprises:

a slotted permeate body having opposing faces;

first and second wire mesh membranes, each of said wire mesh membranes

having a first surface and a second surface, wherein each of said wire mesh membranes

first surfaces is adjacent said slotted permeate;

first and second membranes permeable to a desired fluid, each of said permeable

membranes adjacent one of said wire mesh membranes second surfaces;

a permeate rim surrounding said slotted permeate body;

first retainers adjacent each of said permeable membranes; second retainers between said slotted permeate and each of said wire mesh

membranes; and

gaskets between each of said wire mesh membranes and said permeable

membranes, wherein said permeate rim, said first retainers, said second retainers and said

gaskets are joined together at their peripheries.

3. The fluid separation module of claim 1 , further comprising a plurality of screens,

wherein said plurality of screens are positioned between said first plurality of fluid

separation assemblies and said plurality of screens are positioned between said second

plurality of fluid separation assemblies.

4. The fluid separation module of claim 1, wherein each of said first and second

plurality of fluid separation assemblies comprises:

a fluid permeable membrane; and

a wire mesh membrane adjacent said fluid permeable membrane, said wire mesh

membrane having an intermetallic diffusion barrier.

5. The fluid separation module according to claim 4, wherein said barrier is a thin

film containing at least one of the group consisting of nitrides, oxides, borides, suicides,

carbides and aluminides.

6. The fluid separation module according to claim 5, wherein said barrier is a thin

film containing one of an oxide and a nitride.

7. The fluid separation module according to claim 4, wherein said fluid permeable

membrane is a substantially planar member having a centrally disposed opening.

8. The fluid separation module according to claim 7, wherein said wire mesh

membrane is a substantially planar membrane having a centrally disposed opening which

is in alignment with said fluid permeable membrane opening.

9. The fluid separation module according to claim 4, wherein said wire mesh

membrane has a mesh count ranging between approximately 19 to 1000 mesh per inch.

10. The fluid separation module according to claim 4, further comprising a slotted

permeate plate adjacent to said wire mesh membrane.

11. The fluid separation module according to claim 10, further comprising a second

fluid permeable membrane and a second wire mesh membrane, wherein said slotted

permeate plate has a first side and a second side and said first permeable membrane is

adjacent said first side of said slotted permeate plate and said first wire mesh membrane

is adjacent said first permeable membrane, and wherein said second wire mesh membrane

is adjacent said slotted permeate plate second side and said second fluid permeable

membrane is adjacent said second wire mesh membrane.

12. The fluid separation module according to claim 11 , wherein said slotted permeate

plate, said second wire mesh membrane and said second fluid permeable membrane each

also have a centrally disposed opening and each of said centrally disposed openings are

coaxially aligned and form a central conduit.

13. The fluid separation module according to claim 4, wherein said wire mesh

membrane is made from stainless steel.

14. The fluid separation module according to claim 11, wherein each of said fluid

permeable membranes further comprises a gasket seat, a membrane gasket, and a washer

to form first and second membrane subassembly, wherein said gasket seats, said

membrane gaskets and said washers are connected to said fluid permeable membranes.

15. The fluid separation module according to claim 14, further comprising a weld

bead connected to each of said first and second membrane subassemblies.

16. The fluid separation module according to claim 15, further comprising first

retainers, one of said first retainers connected to each of said fluid permeable membranes.

17. The fluid separation module according to claim 16, further comprising second

retainers adjacent said slotted permeate plate.

18. The fluid separation module according to claim 15, further comprising first

retainers and second retainers, wherein said first retainers and said second retainers are

adjacent each of said fluid permeable membranes.

19. The fluid separation module according to claim 15, further comprising gaskets,

one of said gaskets adjacent each of said wire mesh membranes.

20. The fluid separation module according to claim 10, wherein said permeable

membrane and said slotted permeate each have a centrally disposed opening that form a

conduit.

21. The fluid separation module according to claim 1, wherein said plurality of plates

are a substantially planar member having a gasket connected at the periphery of said

plate.

22. The fluid separation module according to claim 1, wherein said plurality of plates

have a curved portion and a linear portion.

23. The fluid separation module according to claim 1, wherein the said housing is

substantially cylindrical and said plurality of plates has a surface area that is less than said

cross-sectional area of said housing.

24. The fluid separation module according to claim 1 , wherein each of said plurality

of plates defines a plurality of holes therethrough.

25. The fluid separation module according to claim 24, further comprising a plurality

of guide rods that are received by said holes.

26. The fluid separation module according to claim 1 , wherein each of said plurality

of plates has first and second gaskets connected thereto.

27. The fluid separation module according to claim 26, wherein said first and second

gaskets have male and female connectors, respectively.

28. The fluid separation module of claim 1, wherein each of said plurality of plates

has a centrally disposed opening, and wherein each of said first and second plurality of

fluid separation assemblies also has a centrally disposed opening and said openings of

said plurality of plates and said openings of said first and second plurality of fluid

separation assemblies are in coaxial alignment with each other.

29. The fluid separation module according to claim 21, wherein each of said plurality

of plates has a groove extending around a portion of the periphery of each of said

plurality of plates, each of said plurality of plates has a gasket that is received within said

grooves.

30. The fluid separation module of claim 1 , wherein each of said first and second

plurality of fluid separation assemblies has a centrally disposed opening, each of said

centrally disposed openings are in coaxial alignment with each other and form a conduit.

31. The fluid separation module according to claim 1, further comprising several

pluralities of fluid separation assemblies within said housing, said fluid separation

assemblies of each of said several plurality of fluid separation assemblies being adjacent

each other.

32. A method for separating a desired fluid from a fluid mixture, comprising:

providing a housing having a wall;

providing a first plurality of fluid separation assemblies positioned adjacent one

another;

providing a second plurality of fluid separation assemblies positioned adjacent

one another;

positioning a plurality of plates adjacent and between said first and second

plurality of fluid separation assemblies;

forming a passageway defined by said plates and said housing wall;

passing fluid through said passageway and through said first plurality of fluid

separation assemblies and through said second plurality of fluid separation assemblies.