U.S. patent application number 11/325426 was filed with the patent office on 2006-08-10 for non-woven and woven fabric for use as reforming catalyst.
Invention is credited to Masamichi Mikura.
Application Number | 20060178068 11/325426 |
Document ID | / |
Family ID | 36780546 |
Filed Date | 2006-08-10 |
United States Patent
Application |
20060178068 |
Kind Code |
A1 |
Mikura; Masamichi |
August 10, 2006 |
Non-woven and woven fabric for use as reforming catalyst
Abstract
A reforming catalyst is proposed which is used when producing
hydrogen as a fuel for a fuel cell from e.g. utility gas. The
reforming catalyst is a non-woven or woven fabric made up of
composite fibers each including an elongated carbon core, and a
plurality of ribs attached to the carbon core so as to extend in a
longitudinal direction of the carbon core while being
circumferentially spaced apart from each other. The ribs contain a
precious metal. The fabric contains less precious metal and is thus
less expensive.
Inventors: |
Mikura; Masamichi; (Kobe,
JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
36780546 |
Appl. No.: |
11/325426 |
Filed: |
January 5, 2006 |
Current U.S.
Class: |
442/335 ;
442/192; 442/337 |
Current CPC
Class: |
F01N 2330/10 20130101;
F01N 2330/18 20130101; D03D 15/258 20210101; Y10T 442/3089
20150401; F01N 2370/02 20130101; Y10T 442/609 20150401; D04H 3/16
20130101; F01N 3/2835 20130101; Y10T 442/611 20150401; F01N 2330/20
20130101; D10B 2101/20 20130101; D04H 3/002 20130101; D01D 5/36
20130101; D03D 15/47 20210101; F01N 2310/14 20130101; F01N 2240/30
20130101; F01N 2510/06 20130101; D10B 2101/12 20130101; D03D 15/00
20130101 |
Class at
Publication: |
442/335 ;
442/192; 442/337 |
International
Class: |
D03D 15/00 20060101
D03D015/00; D04H 1/00 20060101 D04H001/00; D04H 13/00 20060101
D04H013/00; D04H 5/00 20060101 D04H005/00; D04H 3/00 20060101
D04H003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 10, 2005 |
JP |
2005-034712 |
Claims
1. A non-woven fabric for use as a reforming catalyst, said
non-woven fabric comprising composite fibers each comprising an
elongated carbon core, and a plurality of ribs provided on an outer
periphery of said carbon core so as to extend in a longitudinal
direction of said carbon core while being circumferentially spaced
apart from each other, said ribs containing a precious metal.
2. The non-woven fabric of claim 1 wherein said composite fibers
have a diameter in the range of 5 to 100 micrometers.
3. A woven fabric for use as a reforming catalyst, said woven
fabric comprising composite fibers each comprising an elongated
carbon core, and a plurality of ribs provided on an outer periphery
of said carbon core so as to extend in a longitudinal direction of
said carbon core while being circumferentially spaced apart from
each other, said ribs containing a precious metal.
4. The woven fabric of claim 3 wherein said composite fibers have a
diameter in the range of 5 to 100 micrometers.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to a non-woven fabric for use as a
reforming catalyst used when producing hydrogen as a fuel for a
fuel cell.
[0002] Fuel cells are gathering much attention these days as
next-generation energy generators. Fuel cells generate electricity
by chemically reacting hydrogen as a fuel with oxygen in the
atmosphere. Because of their high generating efficiency and low
burden on the environment, fuel cells are considered to have
limitless applications.
[0003] Hydrogen, which is scarcely present in the atmosphere, is
typically produced by reacting e.g. methanol contained in utility
gas with vapor in the presence of a catalyst in the form of a
precious metal such as platinum.
[0004] For this purpose, JP patent publication 2002-121006A
proposes a reforming catalyst containing a composite oxide of a
predetermined element carrying platinum and zirconium.
[0005] But because a large amount of precious metals are used in
such a catalyst, the cost for producing hydrogen as a fuel for fuel
cells tends to be high.
[0006] An object of the present invention is to provide a reforming
catalyst for producing hydrogen as a fuel for fuel cells from
utility gas which contains small amounts of precious metals and
thus can produce hydrogen at a lower cost.
SUMMARY OF THE INVENTION
[0007] According to the present invention, there is provided a
non-woven fabric for use as a reforming catalyst, the non-woven
fabric comprising composite fibers each comprising an elongated
carbon core, and a plurality of ribs provided on an outer periphery
of the carbon core so as to extend in a longitudinal direction of
the carbon core while being circumferentially spaced apart from
each other, the ribs containing a precious metal. The precious
metal is a precious and chemically stable metal suitable for use as
a catalyst, such as platinum, palladium, rhodium, iridium or
ruthenium.
[0008] From another aspect of the invention, there is provided a
woven fabric for use as a reforming catalyst, the woven fabric
comprising composite fibers each comprising an elongated carbon
core, and a plurality of ribs provided on an outer periphery of the
carbon core so as to extend in a longitudinal direction of the
carbon core while being circumferentially spaced apart from each
other, the ribs containing a precious metal.
[0009] With this arrangement, each composite fiber has its almost
entire outer surface covered with the precious metal, so that the
fabric maintains sufficient catalytic performance with a far
smaller amount of precious metal used than is used in conventional
reforming catalysts comprising metallic plates. Thus, using the
reforming catalyst according to the present invention, it is
possible to reduce the cost for producing hydrogen as a fuel for
fuel cells. The fabric as the reforming catalyst according to the
present invention is lightweight because it contains only a small
amount of precious metal. Since the fabric as the reforming
catalyst according to the invention is mainly made of carbon
fibers, it is flexible and easy to work. Thus, the reforming
catalyst can be used for many different applications.
[0010] The reforming catalyst in the form of a non-woven fabric
according to the present invention has a much greater surface area
than conventional reforming catalysts in the form of metallic
plates and thus is much higher in the efficiency of catalytic
reaction.
[0011] The composite fibers have preferably a diameter in the range
of 5 to 100 micrometers.
[0012] By determining the diameter of the composite fibers in this
range, it is possible to maximize the surface area of the fabric
and thus the efficiency of catalytic reaction while maintaining
sufficient strength to ensure resistance to repeated use as a final
product.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Other features and objects of the present invention will
become apparent from the following description made with reference
to the accompanying drawings, in which:
[0014] FIG. 1 schematically shows how the fabric according to the
present invention is formed by melt blowing;
[0015] FIG. 2 is an enlarged perspective view of a composite fiber
according to the present invention;
[0016] FIG. 3A is a vertical sectional view of a die for forming
composite fibers according to the present invention; and
[0017] FIG. 3B is a sectional view taken along the line B-B of FIG.
3A.
[0018] Now with reference to the drawings, the embodiment of the
invention is described. The embodiment is directed to a method of
manufacturing a non-woven fabric 12 for use as a reforming catalyst
according to the present invention by melt blowing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] First, a polymer 10a and a polymer 10b containing precious
metal powder are prepared. The polymer 10a may be petroleum pitch,
coal pitch, a thermosetting resin such as epoxy resin or phenolic
resin, or a melt spinnable resin containing a curing agent. The
precious metal forming the precious metal powder may be platinum,
palladium, rhodium, iridium or ruthenium. If reduced at a later
stage, the precious metal may also be a metallic salt such as
platinum chloride or platinum oxide. The precious metal powder has
preferably a particle diameter not exceeding 3 micrometers and its
content in the polymer is preferably less than 40 percent by
volume.
[0020] As shown in FIG. 1, a typical melt blow process comprises
the steps of feeding the polymers 10a and 10b into hoppers 20a and
20b, respectively, heat-melting the polymers 10a and 10b in
extruders 30a and 30b, respectively, feeding the polymers 10a and
10b into a die 40, spinning the mixture out of the die 40 in the
form of fibers 11 to deposit the fibers 11 onto a collecting net of
a conveyor 50 in the form of a sheet, peeling the sheet off the
conveyor 50, optionally feeding the sheet through calender rolls
60, and winding the sheet onto a winder 70 as a non-woven fabric
12.
[0021] Each fiber 11 comprises an elongated core 11a made of the
polymer 10a and formed with four longitudinal recesses having an
arcuate section and circumferentially spaced apart from each other
at equal intervals, and four elongated ribs 11b made of the polymer
10b and each filling one of the recesses so that the fiber 11 has a
circular cross-section. Such fibers 11 are formed in the die 40 in
the manner as shown in FIGS. 3A and 3B.
[0022] As shown in FIG. 3A, the die 40 has an axial passage 40d
having a cross-section complementary to the core 11a of each fiber
11, and four radial passages 40e. Each passage 40e merges with the
axial passage 40d at a juncture 40c. Near the juncture 40c, each
passage 40e has a cross-section complementary to one of the
elongated ribs 11b of each fiber 11 (see FIG. 3B). The polymer 10a
is introduced into the axial passage 40d through its inlet port 40a
in a molten state. The polymer 10b is introduced into the radial
passages 40e through their inlet ports 40b in a molten state. The
polymers 10a and 10b thus merge at the juncture 40c and are formed
into fibers 11. The fibers 11 thus formed are discharged through a
spinneret 40f by hot air fed through hot air inlet ports 40g and
hot air blowing slits 40h (FIG. 3A). As shown in FIG. 2, the fibers
11 thus formed have their axial core 11a, which is made of the
polymer 10a, partially exposed. Thus, the fibers 11 maintain
self-adhesiveness during melt blowing.
[0023] The fibers 11 are bonded together into a non-woven fabric
12, which is then calcined at a temperature in the range of 1500 to
1600 degrees C. and subjected to graphitization to allow the
polymers forming the fibers 11 to turn into carbon. A non-woven
fabric for use as a reforming catalyst according to the present
invention is thus formed. The thus formed reforming catalyst
according to the invention is, unlike conventional metallic plates,
easy to work because it is a soft non-woven fabric comprising
carbon fibers. Thus, it can be used for many different
applications. If the polymer 10b contains not a precious metal but
a precious metal salt, it has to be reduced to a metallic element.
The fabric may also be subjected to infusible treatment.
[0024] In the embodiment, the non-woven fabric 12 is formed by melt
blowing. But the non-woven fabric 12 according to the present
invention may be formed by any other known method such as needle
punching, spunlacing or spun-bonding. Also, the catalyst according
to the present invention may be a woven fabric comprising composite
fibers 11. Such a woven fabric may be formed using a conventional
weaving machine or by any known method.
[0025] For higher catalytic efficiency, the fibers forming such a
fabric should have as small a diameter as possible. But
simultaneously, the fabric has to maintain sufficient strength as
an end product. Thus, the fibers forming the fabric have preferably
diameters in the range of about 5 to 100 micrometers.
* * * * *