U.S. patent application number 10/500017 was filed with the patent office on 2004-12-09 for chemical reactor and fuel cell system.
Invention is credited to Shioya, Masaharu, Yamamoto, Tadao.
Application Number | 20040244290 10/500017 |
Document ID | / |
Family ID | 32171065 |
Filed Date | 2004-12-09 |
United States Patent
Application |
20040244290 |
Kind Code |
A1 |
Yamamoto, Tadao ; et
al. |
December 9, 2004 |
Chemical reactor and fuel cell system
Abstract
A chemical reactor includes a first reaction section which has a
first flow path and causes a first reaction in the first flow path.
A heating section heats the first reaction section. A second
reaction section has a second flow path and causes a second
reaction in the second flow path by heat of the heating section
transmitted via the first reaction section.
Inventors: |
Yamamoto, Tadao; (Tokyo,
JP) ; Shioya, Masaharu; (Tokyo, JP) |
Correspondence
Address: |
FRISHAUF, HOLTZ, GOODMAN & CHICK, PC
767 THIRD AVENUE
25TH FLOOR
NEW YORK
NY
10017-2023
US
|
Family ID: |
32171065 |
Appl. No.: |
10/500017 |
Filed: |
June 23, 2004 |
PCT Filed: |
October 10, 2003 |
PCT NO: |
PCT/JP03/13064 |
Current U.S.
Class: |
48/127.9 ;
48/118.5; 48/128; 48/94; 48/95 |
Current CPC
Class: |
B01J 2219/00844
20130101; B01J 2219/00891 20130101; B01J 19/249 20130101; B01J
2219/00961 20130101; B01J 2219/00853 20130101; B01J 2219/00986
20130101; B01J 2219/2479 20130101; B01J 2219/00835 20130101; C01B
3/323 20130101; H01M 8/0668 20130101; B01J 2219/00783 20130101;
H01M 8/0618 20130101; B01J 2219/00788 20130101; C01B 2203/1223
20130101; H01M 8/04156 20130101; H01M 8/04022 20130101; B01J
2219/2453 20130101; H01M 8/04097 20130101; C01B 2203/1076 20130101;
B01J 19/0093 20130101; C01B 2203/085 20130101; H01M 8/0612
20130101; C01B 2203/82 20130101; B01J 2219/0081 20130101; B01J
2219/0086 20130101; B01J 2219/2467 20130101; C01B 2203/044
20130101; C01B 2203/0866 20130101; C01B 2203/146 20130101; B01J
2219/2465 20130101; C01B 2203/0227 20130101; C01B 3/583 20130101;
C01B 2203/169 20130101; C01B 2203/066 20130101; H01M 8/0662
20130101; Y02E 60/50 20130101; C01B 2203/1619 20130101; B01J
2219/00873 20130101; B01J 2219/2458 20130101; C01B 2203/1695
20130101; C01B 2203/047 20130101; C01B 2203/1082 20130101; C01B
2203/00 20130101; C01B 2203/0475 20130101; B01J 2219/00828
20130101; C01B 2203/1288 20130101; C01B 2203/0811 20130101; C01B
2203/0233 20130101 |
Class at
Publication: |
048/127.9 ;
048/094; 048/095; 048/128; 048/118.5 |
International
Class: |
C10J 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 25, 2002 |
JP |
2002-310959 |
Claims
1. A chemical reactor comprising: a first reaction section which
has a first flow path and causes a first reaction in the first flow
path; a heating section which heats the first reaction section; and
a second reaction section which has a second flow path and causes a
second reaction in the second flow path by heat of the heating
section transmitted via the first reaction section.
2. The chemical reactor according to claim 1, wherein the first
reaction and the second reaction are different reactions.
3. The chemical reactor according to claim 1, wherein the second
reaction is caused at a temperature lower than a temperature at
which the first reaction is caused.
4. The chemical reactor according to claim 1, wherein the first
flow path and the second flow path are coupled.
5. The chemical reactor according to claim 1, wherein the second
reaction section has a vaporization reaction section which
vaporizes a generation fuel, and the first reaction section has a
reforming reaction section which reforms the vaporized generation
fuel.
6. The chemical reactor according to claim 1, wherein the first
reaction section has a reforming reaction section which reforms the
generation fuel, and the second reaction section has a carbon
monoxide elimination section which eliminates carbon monoxide
produced in the first reaction section.
7. The chemical reactor according to claim 1, wherein the first
reaction section and the second reaction section are formed on the
same substrate.
8. The chemical reactor according to claim 7, wherein heat of the
heating section is transmitted from the first reaction section to
the second reaction section via the substrate.
9. The chemical reactor according to claim 1, wherein a distance
between the first flow path and the heating section is shorter than
a distance between the second flow path and the heating
section.
10. The chemical reactor according to claim 1, wherein the second
flow path is disposed on a periphery of the first flow path.
11. The chemical reactor according to claim 1, further comprising a
substrate in which grooves configuring the first flow path and the
second flow path are formed.
12. The chemical reactor according to claim 1, wherein the first
reaction section and the second reaction section are micro
reactors.
13. The chemical reactor according to claim 1, further comprising:
a thermometer section which measures temperature of the heating
section.
14. The chemical reactor according to claim 13, further comprising:
a control circuit section which causes the heating section to
generate heat on the basis of temperature information of the
thermometer section.
15. The chemical reactor according to claim 1, wherein the heating
section has a combustion section which performs heating by a
combustion reaction.
16. The chemical reactor according to claim 15, further comprising
a substrate on which the first reaction section is formed, and
wherein the combustion reaction heats the first reaction section
via the substrate.
17. The chemical reactor according to claim 1, wherein the heating
section has a resistive element.
18. The chemical reactor according to claim 1, further comprising:
a third reaction section which has a third flow path and causes a
third reaction in the third flow path by the heat of the heating
section transmitted via the second reaction section.
19. The chemical reactor according to claim 18, wherein the third
reaction is caused at a temperature lower than the temperature at
which the first reaction is caused.
20. The chemical reactor according to claim 18, wherein the third
reaction is caused at a temperature lower than the temperature at
which the second reaction is caused.
21. The chemical reactor according to claim 18, wherein the third
flow path and the first flow path are coupled.
22. The chemical reactor according to claim 18, wherein the third
reaction section has a vaporization reaction section which
vaporizes the generation fuel, the first reaction section has a
reforming reaction section which reforms the vaporized generation
fuel, and the second reaction section has a carbon monoxide
elimination section which eliminates carbon monoxide produced in
the first reaction section.
23. The chemical reactor according to claim 18, further comprising
a single substrate on which the first reaction section, the second
reaction section and the third reaction section are formed.
24. The chemical reactor according to claim 23, wherein the heat of
the heating section is transmitted from the first reaction section
to the second reaction section via the substrate, and further
transmitted from the second reaction section to the third reaction
section via the substrate.
25. The chemical reactor according to claim 18, wherein a distance
between the second flow path and the heating section is shorter
than a distance between the third flow path and the heating
section.
26. The chemical reactor according to claim 18, wherein the third
flow path is disposed on a periphery of the second flow path.
27. A chemical reactor comprising: a plurality of substrates
including first and second substrates laminated on each other; a
first reaction section which has a first flow path between the
first substrate and the second substrate, and causes a first
reaction in the first flow path; a heating section which heats the
first reaction section; and a second reaction section which has a
second flow path between the first substrate and the second
substrate or between the second substrate and another substrate
adjacent to the second substrate, and causes a second reaction in
the second flow path at a temperature, which is lower than a
temperature at which the first reaction is caused, by the heating
section.
28. A fuel cell system comprising: a chemical reactor which
comprises: at least two substrates laminated on each other; a first
reaction section which has a first flow path between the
substrates, and causes a first reaction in the first flow path; a
heating section which heats the first reaction section; and a
second reaction section which has a second flow path between the
substrates, and causes a second reaction in the second flow path at
a temperature, which is lower than a temperature at which the first
reaction is caused, by the heating section; and a fuel cell which
generates electricity by use of a fuel reformed by the chemical
reactor.
Description
TECHNICAL FIELD
[0001] The present invention relates to a chemical reactor and a
fuel cell system.
BACKGROUND ART
[0002] In a technical field of chemical reactions, a chemical
reactor has been known wherein a fluid material flows in a flow
path formed in a substrate so as to produce a desired fluid
material by a chemical reaction. Some of such conventional chemical
reactors are small in size and have a flow path on a micron or
millimeter scale which is formed in a small-sized substrate by use
of a micro fabrication technique accumulated by a semiconductor
manufacturing technique for semiconductor integrated circuits or
the like, and PCT National Publication No. 2001-524019 shows a
chemical micro reactor with a plurality of laminated substrates in
which paths for a reacting fluid are formed. Such chemical reactors
promote a reaction by heating a reaction furnace, and the reaction
furnace itself is small, thus offering advantages that uniform heat
can be transmitted and a reaction can be uniformly induced.
[0003] In one chemical reactor which causes a plurality of
reactions, suitable temperature for each reaction may differ, so
that the temperature needs to be changed locally.
[0004] Therefore, according to advantages of this invention, a
chemical reactor and a fuel cell system are provided which are
capable of performing a plurality of chemical reactions and allow
the entire reactor to be simplified and small in size.
DISCLOSURE OF INVENTION
[0005] The present invention provides a chemical reactor
comprising:
[0006] a first reaction section which has a first flow path and
causes a first reaction in the first flow path;
[0007] a heating section which heats the first reaction section;
and
[0008] a second reaction section which has a second flow path and
causes a second reaction in the second flow path by heat of the
heating section transmitted via the first reaction section.
[0009] The heating section may heat a plurality of reaction
sections, and especially when heating a plurality of reaction
sections with different suitable reaction temperatures, the heating
section can heat, by heating one reaction section, heat the other
reaction section via the one reaction section, thereby causing
reactions in both the reaction sections at their suitable
temperatures. A substrate in which the flow paths are formed to
cause reactions is preferable for this kind of heat transmission,
but if thermal conductivity of the substrate is too good,
temperature of the heat that reaches the reaction section requiring
a lower temperature might not be low enough. In such a case, it is
possible to adjust the temperature by providing slits in portions
of the substrate to block the heat transmission.
BRIEF DESCRIPTION OF DRAWINGS
[0010] FIG. 1 is a block diagram showing essential parts of one
example of a fuel cell system comprising a chemical reactor as one
embodiment of this invention;
[0011] FIG. 2 is a perspective view of the essential parts of the
chemical reactor shown in FIG. 1;
[0012] FIG. 3 is a cross sectional view along the line III-III of
FIG. 2;
[0013] FIG. 4 is a transmitted plan view of a part corresponding to
a first substrate shown in FIG. 3;
[0014] FIG. 5 is a transmitted plan view of a part corresponding to
a second substrate shown in FIG. 3;
[0015] FIG. 6 is a transmitted plan view of a part corresponding to
a third substrate shown in FIG. 3;
[0016] FIG. 7 is a graph showing changes with time of heating
temperatures in a vaporization flow path, a reforming flow path and
a carbon monoxide elimination flow path;
[0017] FIG. 8 is a schematic configuration diagram of a fuel cell
section and a charging section shown in FIG. 1;
[0018] FIG. 9 is a cross sectional view similar to FIG. 3 showing
the essential parts of the chemical reactor as another embodiment
of this invention;
[0019] FIG. 10 is a transmitted plan view of a part corresponding
to a fourth substrate shown in FIG. 9;
[0020] FIG. 11 is a cross sectional view similar to FIG. 3 showing
the essential parts of the chemical reactor as still another
embodiment of this invention; and
[0021] FIG. 12 is a perspective view showing the partially broken
fuel cell system comprising the chemical reactor of the present
invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0022] Next, a micro chemical reactor as one embodiment of this
invention which is applied to a reforming reactor of a fuel
reforming type fuel cell system will be described. FIG. 1 is a
block diagram showing essential parts of one example of a fuel cell
system 1. This fuel cell system 1 comprises a generation fuel
section 2, a combustion fuel section 3, a micro chemical reactor 4,
a fuel cell section 5 and a charging section 6.
[0023] The generation fuel section 2 includes a generation fuel
storage container in which a generation fuel 68 (e.g., a methanol
solution) is sealed, and supplies the generation fuel 68 to the
micro chemical reactor 4. The combustion fuel section 3 includes a
combustion fuel storage container in which a combustion fuel 69
(e.g., methanol) is sealed, and supplies the combustion fuel 69 to
the micro chemical reactor 4. The micro chemical reactor 4 includes
a generation fuel vaporization section 7 which vaporizes the fluid
generation fuel 68, a reforming reaction section 8 which reforms
the vaporized generation fuel 68, a carbon monoxide elimination
section 9 which eliminates carbon monoxide contained in the
reformed fluid, a combustion section 10 for heating the generation
fuel vaporization section 7, the reforming reaction section 8 and
the carbon monoxide elimination section 9, and a thin film heater
section 11.
[0024] FIG. 2 is a perspective view of essential parts of the micro
chemical reactor 4. The micro chemical reactor 4 includes a first
substrate 12, a second substrate 13 and a third substrate 14 that
are small-sized and laminated on each other. Three substrates 12 to
14 are accommodated in an outer package constituted of a first
outer panel 15 and a second outer panel 16 that are joined to each
other. In other words, concave parts 17 and 18 are formed in
surfaces opposite to each other of the first and second outer
panels 15 and 16, and the first to third substrates 12 to 14 are
accommodated in these concave parts 17 and 18. Glass is one example
for a material of the first to third substrates 12 to 14 and of the
first and second outer panels 15 and 16, but silicon, ceramic,
metal simple substance (e.g., aluminum), metal alloys, metallic
compounds and the like which have excellent workability may be used
for the first substrate 12 and the third substrate 14 in which
after-mentioned flow paths are formed.
[0025] At three predetermined portions of the first outer panel 15,
round through-holes 24, 25 and 26 are formed into which first end
portions of a generation fuel supply tubule 21, a generation
product discharge tubule 22 and an oxygen supply tubule 23 are
inserted. At three predetermined portions of the second outer panel
16, round through-holes 30, 31 and 32 are formed into which first
end portions of a combustion fuel supply tubule 27, a combustion
gas discharge tubule 28 and an oxygen supply tubule 29 are
inserted. At predetermined portions of the first outer panel 15, a
plurality of round through-holes 34 are formed into which first end
portions of a plurality of electrodes 33 are inserted. The
plurality of electrodes 33 function as a signal wire group for
electrically controlling the thin film heater or the heater section
11, which heats the generation fuel vaporization section 7 and the
reforming reaction section 8 of the micro chemical reactor 4
described later, and for electrically controlling a first micro
pump 46 (see FIG. 1), and also function as wires for sending and
receiving signals including temperature data detected by a
thermometer section 19 which detects temperature in the micro
chemical reactor 4.
[0026] FIG. 3 is a cross sectional view along the line III-III of
FIG. 2 and the line III-III of FIG. 4. FIG. 4 is a transmitted plan
view of a part corresponding to the first substrate 12, FIG. 5 is a
transmitted plan view of a part corresponding to the second
substrate 13; and FIG. 6 is a transmitted plan view of a part
corresponding to a third substrate 14. On inner wall surfaces of
the concave part 17 of the first outer panel 15 and the concave
part 18 of the second outer panel 16, heat radiation prevention
films 35, which are formed of a metal such as Au, Ag or Al with
high heat ray reflectivity, are provided except for portions
corresponding to the round transmitting holes 24, 25, 26, 30, 31,
32 and 34 shown in FIG. 2.
[0027] On outermost surfaces of the first to third substrates 12 to
14, that is, on an upper surface (surface opposite to a side facing
the second substrate 13) and side surfaces of the first substrate
12, side surfaces of the second substrate 13, and a lower surface
(surface opposite to a side facing the second substrate 13) and
side surfaces of the third substrate 14, a heat generation
prevention film 36 formed of the same material as above is provided
except for the portions corresponding to the round transmitting
holes 24, 25, 26, 30, 31, 32 and 34 shown in FIG. 2 and except for
portions corresponding to slits 56 described later.
[0028] A space or clearance 37 is provided between the heat
generation or release prevention film 36 laid on the outermost
surfaces of the first to third substrates 12 to 14 and the heat
generation prevention films 35 laid on the inner surfaces of the
first and second outer panels 15 and 16 so that the least heat
released from the first to third substrates 12 to 14 is transmitted
to the first and second outer panels 15 and 16. At a plurality of
predetermined portions of the space 37, a plurality of pressure
resistant spacers 38 is provided to hold the first to third
substrates 12 to 14 and to maintain the width of the aperture 37.
Two of the plurality of pressure resistant spacers 38 are provided
for each surface of the first to third substrates 12 to 14.
[0029] The aperture 37 inhibits the heat generated as described
later in the first to third substrates 12 to 14 from being released
into the atmosphere, and a vacuum is formed in the aperture 37 or a
gas with low thermal conductivity (such as atmospheric air, carbon
dioxide gas or chlorofluorocarbon) fills the aperture 37. The heat
release prevention films 35 and 36 inhibit heat generation from the
outermost surfaces of the first to third substrates 12 to 14 to the
outside of the first and second outer panels 15 and 16, and any one
of the heat generation prevention films may be dispensed with.
[0030] As shown in FIG. 4, a vaporization flow path groove 57, a
reforming flow path groove 58 and a carbon monoxide elimination
flow path groove 59 are continuously formed in the inner surface of
the first substrate 12. The vaporization flow path groove 57 of the
first substrate 12 and an opposite surface of the second substrate
13 are combined with each other to form a vaporization flow path 41
in which the fluid generation fuel 68 flows while being vaporized.
The reforming flow path groove 58 of the first substrate 12 and the
opposite surface of the second substrate 13 are combined with each
other to form a reforming flow path 42 in which the fluid resulting
from the vaporized generation fuel 68 flows while being reformed.
The carbon monoxide elimination flow path groove 59 of the first
substrate 12 and the opposite surface of the second substrate 13
are combined with each other to form a carbon monoxide elimination
flow path 43 in which the fluid resulting from the reformed
generation fuel 68 flows while carbon monoxide contained therein is
being eliminated. The vaporization flow path 41 is provided making
about one round and a half from a lower left corner in a clockwise
direction with a total length of 1 cm or more and 10 cm or less
around a peripheral part of the inner surface (surface opposite to
the second substrate 13) of the first substrate 12. The meandering
reforming flow path 42 is provided continuously from the
vaporization flow path 41 with a total length of 3 cm or more and
20 cm or less in a central part of the inner surface of the first
substrate 12, as indicated by hatching. The suitably meandering
carbon monoxide elimination flow path 43 is provided continuously
from the reforming flow path 42 with a total length of 3 cm or more
and 20 cm or less on the inner surface of the first substrate 12
except for the peripheral part and central part. The width and
depth of the vaporization flow path 41, the reforming flow path 42
and the carbon monoxide elimination flow path 43 are both about 500
.mu.m or less as one example. In this way, a terminal end of the
vaporization flow path 41 is coupled to a starting end of the
reforming flow path 42, and a terminal end of the reforming flow
path 42 is coupled to a starting end of the carbon monoxide
elimination flow path 43.
[0031] The vaporization flow path 41 constitutes the generation
fuel vaporization section 7, which is a reaction furnace where the
generation fuel 68 in liquid form is vaporized. The vaporization
flow path 41 is not provided with a reaction catalyst therein. The
reforming flow path 42 constitutes the reforming reaction section
8, which is a reaction furnace where the generation fuel 68
vaporized by the generation fuel vaporization section 7 is
reformed. In this case, a surface of the reforming flow path groove
58 in the reforming flow path 42 is provided with a reforming
catalyst layer 44 (see FIG. 3) which is formed of reforming
catalyst such as Cu or ZnO, supported by a porous support film such
as Al.sub.2O.sub.3. The carbon monoxide elimination flow path 43
constitutes a reaction furnace of the carbon monoxide elimination
section 9, which is a reaction furnace where carbon monoxide
contained in a by-product produced by the reforming reaction
section 8 is eliminated. In this case, a surface of the carbon
monoxide elimination flow path groove 59 in the carbon monoxide
elimination flow path 43 is provided with a selective oxidative
catalyst layer 45 (see FIG. 3) which is formed of reforming
catalyst such as PT, supported by a porous support film such as
Al.sub.2O.sub.3.
[0032] The first micro pump 46 is provided at a predetermined
position in the lower left corner of the inner surface of the first
substrate 12. The first micro pump 46 takes in from the generation
fuel section 2 an amount of generation fuel 68 corresponding to a
signal which is provided from a control circuit section 20 (see
FIG. 1) in the fuel cell system 1 via the electrodes 33 or the
like, and then supplies it to the starting end of the vaporization
flow path 41 via the generation fuel supply tubule 21.
[0033] The first micro pump 46 may be ultra small and injects a
liquid in a form of particles from a nozzle while controlling its
injection amount. The first micro pump 46 is preferably, for
example, an injector which heats a liquid in the nozzle so as to
inject the liquid in a particle form by pressure of air bubbles in
the nozzle produced by film boiling; an injector (so-called
piezojet method) which injects liquid in the nozzle in the particle
form by pressure waves caused in the nozzle due to deformation of
an electrostriction element (piezo element); or an injector
(so-called electrostatic jet method) which injects liquid in the
nozzle in the particle form by vibration due to electrostatic force
of a diaphragm in the nozzle. The same applies to a second micro
pump 47 or the like described later.
[0034] One end of the oxygen supply tubule 23 is connected to a
predetermined portion 43a in the vicinity of the starting end of
the carbon monoxide elimination flow path 43. By driving a fourth
micro pump 49 provided outside the micro chemical reactor 4, oxygen
(air) in the atmosphere is supplied to the predetermined portion
43a in the vicinity of the starting end of the carbon monoxide
elimination flow path 43 via the oxygen supply tubule 23. A third
micro pump 48 controls a supply amount of oxygen in accordance with
a signal provided from the control circuit section 20 in the fuel
cell system 1. One end of the generation product discharge tubule
22 is connected to a predetermined portion 43b in the vicinity of
the terminal end of the carbon monoxide elimination flow path
43.
[0035] As shown in FIG. 3 and FIG. 5, the thin film heater section
11 comprising a heat generation resistive element thin film such as
TaSiOx or TaSiOxN which generates heat in accordance with a voltage
applied by a signal from the control circuit section 20 is provided
at a portion opposite to the reforming flow path 42 on a surface of
the second substrate 13 opposite to the first substrate 12. The
thin film heater section 11 is disposed in the reforming flow path
42, utilized as a heat source required for an initial state of a
reforming reaction in the reforming flow path 42 of the reforming
reaction section 8, controls temperature in the reforming flow path
42, and is also utilized as a heat source required for an initial
state of chemical reactions in the vaporization flow path 41 of the
generation fuel vaporization section 7 and in the carbon monoxide
elimination flow path 43 of the carbon monoxide elimination section
9.
[0036] Heating in the reforming flow path 42 is achieved by heat
energy mainly generated in the combustion section 10 (details of
which will be described later) shown in FIG. 1. The thin film
heater 11 is used secondarily. In other words, the combustion
section 10 is mainly the source of heat transmitted to promote
reactions in the vaporization flow path 41 of the generation fuel
vaporization section 7, in the reforming flow path 42 of the
reforming reaction section 8, and in the carbon monoxide
elimination flow path 43 of the carbon monoxide elimination section
9. The thin film heater 11 has a fine adjusting function so that
suitable temperatures are obtained in the vaporization flow path
41, the reforming flow path 42 and the carbon monoxide elimination
flow path 43 in accordance with a signal provided from the control
circuit section 20 in the fuel cell system 1 via the electrodes 33
or the like.
[0037] The thin film thermometer section 19 constituted by a thin
film thermometer or a semiconductor thin film thermocouple is
provided in the vicinity of the reforming flow path 42. The thin
film thermometer section 19 detects temperature in the vaporization
flow path 41 of the generation fuel vaporization section 7 heated
by the combustion section 10 and the thin film heater 11,
temperature in the reforming flow path 42 of the reforming reaction
section 8 and temperature in the carbon monoxide elimination flow
path 43 of the carbon monoxide elimination section 9, and then
provides their temperature detection signals to the control circuit
section 20 in the fuel cell system 1 via the electrodes 33 or the
like. On the basis of these temperature detection signals, the
control circuit section 20 in the fuel cell system 1 controls the
heat generation of the thin film heater 11 so that suitable
temperatures are obtained in the vaporization flow path 41 of the
generation fuel vaporization section 7, in the reforming flow path
42 of the reforming reaction section 8 and in the carbon monoxide
elimination flow path 43 of the carbon monoxide elimination section
9.
[0038] The above-mentioned thin film heater section 11 including
the heat generation resistive element thin film can serve also as
the accurate thermometer section 19 as long as it shows a
resistance change which is linear with respect to a heating
temperature t and which is large. In other words, at least two
terminals connected to the electrodes 33 are set to be connected to
both ends of the thin film heater section 11, and a voltage is
applied across these two terminals, thereby heating the thin film
heater section 11. In this case, because resistance of the thin
film heater section 11 is dependent on the heating temperature, the
control circuit section 20 can read a resistance change in the thin
film heater section 11 by reading a change of the voltage across
the two terminals via the electrodes 33. Such a configuration
enables a higher density package.
[0039] Around a peripheral part of the inner surface (surface
facing the second substrate 13) of the third substrate 14, a
combustion fuel vaporization flow path groove 51 is continuously
cut in a clockwise direction making about one round and a half in
such a manner that it overlaps and extends along the reforming flow
path 42 of the first substrate 12 as shown in FIG. 6. As indicated
by hatching in FIG. 6, a combustion flow path groove 52 is formed
meanderingly in such a manner that it overlaps and extends along
the reforming flow path 42 of the first substrate 12. A linear
discharge flow path groove 53 is cut at the lower left of the
central part of the inner surface of the third substrate 14. A
terminal end of the combustion fuel vaporization flow path groove
51 communicates with a starting end of the combustion flow path
groove 52. A terminal end of the combustion flow path groove 52
communicates with a starting end of the discharge flow path groove
53. The combustion fuel vaporization flow path groove 51 of the
third substrate 14 and the opposite surface of the second substrate
13 are combined with each other to form a combustion fuel
vaporization flow path 75. The combustion flow path groove 52 of
the third substrate 14 and the opposite surface of the second
substrate 13 are combined with each other to form a combustion flow
path 76. The discharge flow path groove 53 of the third substrate
14 and the opposite surface of the second substrate 13 are combined
with each other to form a discharge flow path 77. In the combustion
flow path 76 among the above flow paths, a combustion catalyst
layer 54 (see FIG. 3) made of Pt, Au, Ag and the like is provided
in the combustion flow path groove 52. The combustion flow path 76
functions as the combustion section 10. The width and depth of the
combustion fuel vaporization flow path 75, the combustion flow path
76, and the discharge flow path 77 are both about 500 .mu.m or less
as one example.
[0040] The second micro pump 47 is provided at a predetermined
position in the lower left corner of the inner surface of the third
substrate 14. The second micro pump 47 is automatically supplied
with the combustion fuel 69 from the combustion fuel section 3 via
the combustion fuel supply tubule 27 by a capillary phenomenon or
by driving of the second micro pump 47. The second micro pump 47
injects the combustion fuel 69 into an starting end of the
combustion fuel vaporization flow path 75 while controlling its
injection amount in accordance with a signal provided from the
control circuit section 20 in the fuel cell system 1 via the
electrodes 33 or the like.
[0041] At a predetermined portion 75a of a terminal end of the
combustion fuel vaporization flow path 75, the round transmitting
hole 32 is formed in the second outer panel 16 so as to communicate
with one end of the oxygen supply tubule 29 shown in FIG. 2, and a
through-hole is formed in the third substrate 14. By driving the
third micro pump 48 provided outside the micro chemical reactor 4,
oxygen (air) in the atmosphere is supplied to the predetermined
portion 75a in the vicinity of the terminal end of the combustion
fuel vaporization flow path 75 via the oxygen supply tubule 29. The
third micro pump 48 controls a supply amount of oxygen in
accordance with a signal provided from the control circuit section
20 in the fuel cell system 1. One end of the combustion gas
discharge tubule 28 shown in FIG. 2 is connected to the terminal
end of the discharge flow path 77. The other end of the combustion
gas discharge tubule 28 communicates with the outside of the fuel
cell system 1, and is open to the atmosphere.
[0042] Here, as shown in FIG. 3 to FIG. 6, the reforming flow path
42, the thin film heater 11 and the combustion flow path 76 are
disposed at the same position in a planar view. The width of the
thin film heater 11 is narrower than that of the reforming flow
path 42 so that it can be received in the reforming flow path
groove 58. In parts of the first to third substrates 12 to 14 on a
periphery of an area where the reforming flow path 42, the thin
film heater 11 and the combustion flow path 76 are disposed, four
slits 56 are respectively formed. The slits 56 constitute a low
efficiency thermal conduction section whose thermal conductivity is
lower than those of the first to third substrates 12 to 14, and
carry out an adjustment so that heat energy generated by the
combustion section 10 and the thin film heater 11 as described
later will not be excessively transmitted to the vaporization flow
path 41 and the carbon monoxide elimination flow path 43 via the
first to third substrates 12 to 14 to cause overheat in the
vaporization flow path 41 and the carbon monoxide elimination flow
path 43. The slits 56 are filled with a gas with low thermal
conductivity (such as atmospheric air, carbon dioxide gas or
chlorofluorocarbon) or have an atmosphere depressurized to 1 Pa or
less.
[0043] Next, operation of the micro chemical reactor 4 having the
above configuration will be described. First, when the combustion
fuel 69 (e.g., methanol) in liquid form is supplied from the second
micro pump 47 to the starting end of the combustion fuel
vaporization flow path 75, heat energy due to only initial heat
generation of the thin film heater 11 is transmitted to the
combustion fuel vaporization flow path groove 51 via the first to
third substrates 12 to 14, thereby heating the inside of the
combustion fuel vaporization flow path 75 to a predetermined
temperature. In the combustion fuel vaporization flow path 75, the
combustion fuel 69 is heated and thus vaporized to become a
combustion fuel gas (e.g., CH.sub.3OH if the combustion fuel 69 is
methanol).
[0044] This produced combustion fuel gas (CH.sub.3OH) is mixed with
oxygen (air) supplied via the oxygen supply tubule 29 from the
atmosphere at the predetermined portion 75a in the vicinity of the
terminal end of the combustion fuel vaporization flow path 75. When
this mixed gas (CH.sub.3OH+O.sub.2) is supplied into the combustion
flow path 76 having the combustion catalyst layer 54, the supplied
mixed gas is combusted on the combustion catalyst layer 54 by a
combustion reaction indicated by the following equation (1), and
heat energy is generated by this combustion.
CH.sub.3OH+(3/2)O.sub.2.fwdarw.CO.sub.2+2H.sub.2O (1)
[0045] This heat energy mainly heats the inside of the reforming
flow path 42, and is then transmitted to the first to third
substrates 12 to 14, and heats the inside of the carbon monoxide
elimination flow path 43 of the carbon monoxide elimination section
9 and the inside of the vaporization flow path 41 of the generation
fuel vaporization section 7. After that, the thin film heater 11
stops or reduces only the initial heat generation, and the
subsequent heat generation is controlled by the control circuit
section 20 in the fuel cell system 1 in accordance with the
temperature detection signal of the thermometer section 19. On the
other hand, the combustion gas (CO.sub.2) on a right side of the
above equation (1) is released into the atmosphere via the
discharge flow path 77 and the combustion gas discharge tubule 28.
By-product water is collected by a by-product collecting section
109 described later.
[0046] Here, a required heating temperature in the reaction furnace
of the reforming reaction section 8 constituted by the reforming
flow path 42 is about 250 to 320.degree. C., and a required heating
temperature in the reaction furnace of the carbon monoxide
elimination section 9 constituted by the carbon monoxide
elimination flow path 43 is lower than the above and is about 160
to 220.degree. C., and a required heating temperature in the
reaction furnace of the generation fuel vaporization section 7
constituted by the vaporization flow path 41 is still lower than
the above and is about 100 to 150.degree. C. The vaporization flow
path 41 may be provided with a metal film therein whose thermal
conductivity is higher than those of the first substrate 12 and the
second substrate 13 to effectively absorb the heat from the heat
source and emit it into the flow path.
[0047] As described above, the combustion flow path 76 of the
combustion section 10 and the thin film heater 11, which are the
heat sources, are disposed in the central part of the first to
third substrates 12 to 14, and the reforming flow path 42 of the
reforming reaction section 8 whose required heating temperature
(about 250 to 320.degree. C.) is the highest is disposed in the
central part, and outside this, the carbon monoxide elimination
flow path 43 of the carbon monoxide elimination section 9 whose
required heating temperature (about 160 to 220.degree. C.) is lower
than the above is disposed, and further outside this, the
vaporization flow path 41 of the generation fuel vaporization
section 7 whose required heating temperature (about 100 to
150.degree. C.) is still lower is disposed. In this way, the
distance from the combustion section 10 is shorter in the order of
the reforming flow path 42, the carbon monoxide elimination flow
path 43 and the vaporization flow path 41, and the distance from
the thin film heater 11 is shorter in the order of the reforming
flow path 42, the carbon monoxide elimination flow path 43 and the
vaporization flow path 41. Thus, the heat energy generated in the
combustion section 10 and the thin film heater 11 first heats the
reforming reaction section 8 at its required heating temperature.
The temperature decreases as the heat energy is transmitted through
the first to third substrates 12 to 14. When it reaches the carbon
monoxide elimination section 9 positioned on a periphery of the
reforming reaction section 8, the temperature lowers to the
required heating temperature of the carbon monoxide elimination
section 9. Finally, when it reaches the generation fuel
vaporization section 7 positioned outside the carbon monoxide
elimination section 9 via the first to third substrates 12 to 14,
the temperature lowers to the required heating temperature of the
generation fuel vaporization section 7. Thus, the generation fuel
vaporization section 7, the reforming reaction section 8 and the
carbon monoxide elimination section 9 are respectively heated to
their suitable temperatures.
[0048] While the heating temperature is easily controlled in the
thin film heater 11, it is difficult to accurately control the
heating temperature in the reforming flow path 42 by control of the
combustion reaction in the combustion flow path 76 of the
combustion section 10. Therefore, the heat energy generated by the
combustion reaction in the combustion flow path 76 is brought to,
for example, about 190 to 300.degree. C., which is slightly lower
than the required heating temperature (about 250 to 320.degree. C.)
in the reforming flow path 42 of the reforming reaction section 8.
Then, the control circuit section 20 receives information on the
temperature in the reforming flow path 42 from the electrodes 33
and feeds back electric power to be supplied to the thin film
heater 11, so that the required heating temperature can be rapidly
reached, and fine temperature control that continuously maintains
the required temperature can be achieved, whereby the generation
fuel vaporization section 7. Accordingly, the reforming reaction
section 8 and the carbon monoxide elimination section 9 can be kept
within the required heating temperatures.
[0049] If materials for the first to third substrates 12 to 14 are
glass, silicon, ceramic, metals and the like, their thermal
conductivities are significantly higher than that of the air, so
that without any measures to be taken, the temperature becomes
about the same throughout the first to third substrates 12 to 14.
Therefore, as described above, the four slits 56 are provided in
the parts of the first to third substrates 12 to 14 at the
periphery of the area where the combustion flow path 76 of the
combustion section 10, the thin film heater 11, and the reforming
flow path 42 of the reforming reaction section 8 are disposed, and
a vacuum is formed in the atmosphere inside these slits 56 or a gas
with low thermal conductivity (such as atmospheric air, carbon
dioxide gas or chlorofluorocarbon) fills the atmosphere inside
these slits 56, whereby it is possible to inhibit the heat energy
generated in the combustion section 10 and the thin film heater 11
from being excessively transmitted into the carbon monoxide
elimination flow path 43 and the vaporization flow path 41 via the
first to third substrates 12 to 14. Porous structures with heat
transmission properties made of ceramic or the like may be
contained in the slits 56.
[0050] In the case of only the first to third substrates 12 to 14,
because their sizes are small and a ratio of a surface area to a
volume is large, the heat energy released into the atmosphere
becomes large, and utilization efficiency of heat energy becomes
lower. Therefore, as described above, the first to third substrates
12 to 14 are covered with the first and second outer panels 15 and
16, and the space 37 is provided therebetween, and then a vacuum is
formed in or a gas with low thermal conductivity (such as
atmospheric air, carbon dioxide gas, chlorofluorocarbon or inactive
gas) fills the atmosphere of the space 37, and then the outer
surfaces of the first to third substrates 12 to 14 are covered with
the heat generation prevention film 36 and the inner surfaces of
the first outer panel 15 and the second outer panel 16 are covered
with the heat generation prevention film 35, whereby it becomes
possible to inhibit the heat energy generated by the combustion
section 10 and the thin film heater 11 from being released into the
atmosphere, and to improve efficiency in utilization of heat
energy.
[0051] In the case where the first to third substrates 12 to 14 are
covered with the first and second outer panels 15 and 16 to reduce
the heat released into the atmosphere, if the temperature in the
first and second outer panels 15 and 16 increases too high and it
is difficult to maintain temperature distribution in the first to
third substrates 12 to 14 at an initial value even after
transmitted heat is adjusted by the slits 56, all or part of the
plurality of pressure resistant spacers 38 is formed of a material
with high thermal conductivity such as a metal or glass, and the
heat is moderately released outside the micro chemical reactor 4
via the pressure resistant spacers 38. Thus, the temperature
distribution in the first to third substrates 12 to 14 can be
brought to the initial value. Furthermore, when the heat generation
of the thin film heater 11 and the combustion section 10 is
stopped, such heat release by use of the pressure resistant spacers
38 can serve to rapidly lower the temperature in the first and
second outer panels 15 and 16.
[0052] In this way, the fuel cell system 1 adjusts the heat
released to the outside thereof via the pressure resistant spacers
38, so that the temperature distribution in the first to third
substrates 12 to 14 can be maintained at the initial value.
[0053] Here, after heated with the heat energy generated in the
combustion section 10 and the heat energy generated in the thin
film heater 11, changes with time of the respective heating
temperatures in the vaporization flow path 41, the reforming flow
path 42 and the carbon monoxide elimination flow path are checked,
thereby obtaining results shown in FIG. 7. In FIG. 7, a solid line
indicates the heating temperature in the reforming flow path 42 of
the reforming reaction section 8, a broken line indicates the
heating temperature in the carbon monoxide elimination flow path 43
of the carbon monoxide elimination section 9, and a dashed line
indicates the heating temperature in the vaporization flow path 41
of the generation fuel vaporization section 7.
[0054] As apparent from FIG. 7, after about 40 seconds from the
start of heat generation, each heating temperature is almost
stabilized, and the heating temperature in the reforming flow path
42 indicated by the solid line can be about 300.degree. C., and the
heating temperature in the carbon monoxide elimination flow path 43
indicated by the broken line can be about 200.degree. C., and
further the heating temperature in the vaporization flow path 41
indicated by the dashed line can be about 150.degree. C.
[0055] In this way, by heating with the heat energy generated in
the combustion flow path 76 of the combustion section 10 and the
heat energy generated by the thin film heater 11, the heating
temperature in the reaction furnace of the reforming reaction
section 8 constituted by the reforming flow path 42 is brought to
the required heating temperature of about 250 to 320.degree. C.,
the heating temperature in the reaction furnace of the carbon
monoxide elimination section 9 constituted by the carbon monoxide
elimination flow path 43 is brought to the required heating
temperature of about 160 to 220.degree. C., and the heating
temperature in the reaction furnace of the generation fuel
vaporization section 7 constituted by the vaporization flow path 41
is brought to the required heating temperature of about 100 to
150.degree. C.
[0056] When the generation fuel 68 in liquid form (e.g., a methanol
solution) is supplied to the starting end of the vaporization flow
path 41 from the first micro pump 46, the generation fuel 68 is
vaporized in the vaporization flow path 41 which is heated to the
required heating temperature of about 100 to 150.degree. C. inside,
and the generation fuel gas (e.g., CH.sub.3OH(g)+H.sub.2O(g) when
the generation fuel 68 is a methanol solution) is generated. In
other words, the generation fuel gas (CH.sub.3OH+H.sub.2O) is
generated in the generation fuel vaporization section 7.
[0057] This generated generation fuel gas (CH.sub.3OH+H.sub.2O) is
supplied into the reforming flow path 42. In other words, the
generation fuel gas (CH.sub.3OH+H.sub.2O) generated in the
generation fuel vaporization section 7 is supplied to the reforming
reaction section 8. Then, when the generation fuel gas
(CH.sub.3OH+H.sub.2O) is supplied into the reforming flow path 42
having the reforming catalyst layer 44, an endothermal reaction as
indicated by the following equation (2) is caused in the reforming
flow path 42 because the inside of the reforming flow path 42 is
heated to the required heating temperature of about 250 to
320.degree. C., thereby producing hydrogen and by-product carbon
dioxide.
CH.sub.3OH+H.sub.2O.fwdarw.3H.sub.2+CO.sub.2.fwdarw.(2)
[0058] At this time, a slight amount of carbon monoxide might be
produced in the reforming flow path 42. These products (hydrogen,
carbon dioxide and the slight amount of carbon monoxide) are
supplied into the carbon monoxide elimination flow path 43. In
other words, hydrogen, carbon dioxide and the slight amount of
carbon monoxide produced in the reforming reaction section 8 are
supplied to the carbon monoxide elimination section 9. These
products (hydrogen, carbon dioxide and the slight amount of carbon
monoxide) are mixed with oxygen (air) supplied via the oxygen
supply tubule 23 from the atmosphere outside the fuel cell system 1
at the predetermined portion 43a in the vicinity of the starting
end of the carbon monoxide elimination flow path 43. In this case,
a check valve is provided in the oxygen supply tubule 23, so that
the products do not leak outside the fuel cell system 1.
[0059] When a mixture (hydrogen, carbon dioxide, the slight amount
of carbon monoxide and oxygen) is supplied into the carbon monoxide
elimination flow path 43 having the selective oxidative catalyst
layer 45, carbon monoxide and oxygen are reacted in carbon monoxide
elimination flow path 43 whose inside is heated to the required
heating temperature of about 160 to 220.degree. C., thereby
producing carbon dioxide as indicated by the following equation
(3).
CO+(1/2)O.sub.2.fwdarw.O.sub.2+CO.sub.2 (3)
[0060] Finally, most of fluids reaching the terminal end of the
carbon monoxide elimination flow path 43 that constitutes the
reaction furnace of the carbon monoxide elimination section 9 are
hydrogen and carbon dioxide. These products are discharged outside
via the generation product discharge tubule 22, but, out of these
products, carbon dioxide is separated from hydrogen by a separation
section 66 (see FIG. 1) to be released outside the fuel cell system
1. Therefore, hydrogen and water vapor are supplied from the carbon
monoxide elimination section 9 to the fuel cell section 5.
[0061] As described above, in the micro chemical reactor 4 having
the above configuration, in the inner surface of the first
substrate 12, the vaporization flow path 41 which constitutes the
reaction furnace of the generation fuel vaporization section 7, the
reforming flow path 42 which constitutes the reaction furnace of
the reforming reaction section 8 and the carbon monoxide
elimination flow path 43 which constitutes the reaction furnace of
the carbon monoxide elimination section 9 are continuously provided
within the same substrate, so that three chemical reactions can be
successively caused in three kinds of flow paths, i.e., the
vaporization flow path 41, the reforming flow path 42 and the
carbon monoxide elimination flow path 43, thereby enabling the
whole reactor to be simple and compact.
[0062] Furthermore, the combustion flow path 76 of the combustion
section 10 and the thin film heater 11, which are the heat sources,
are disposed in the central part of the first to third substrates
12 to 14, and the reforming flow path 42 of the reforming reaction
section 8 whose required heating temperature (about 250 to
320.degree. C.) is the highest is disposed in the central part, and
outside this, the carbon monoxide elimination flow path 43 of the
carbon monoxide elimination section 9 whose required heating
temperature (about 160 to 220.degree. C.) is lower than the above
is disposed, and further outside this, the vaporization flow path
42 of the generation fuel vaporization section 7 whose required
heating temperature (about 100 to 150.degree. C.) is still lower is
disposed, and the slits 56 adjust the transmitted heat, whereby
efficient heating can be achieved in the vaporization flow path 41,
the reforming flow path 42 and the carbon monoxide elimination flow
path 43 so as to reform the generation fuel 68.
[0063] Next, the fuel cell section 5 and the charging section 6
will be described. The fuel cell section 5 is constituted by a
solid macromolecule type fuel cell as shown in FIG. 8. More
specifically, the fuel cell section 5 has a cathode 61 is formed of
a carbon electrode to which catalysts such as Pt and C are stuck,
an anode 62 formed of a carbon electrode to which catalysts such as
Pt, Ru and C are stuck. A film-like ion conductive film 63 is
placed between the cathode 61 and the anode 62, thereby supplying
electric power to the charging section 6 constituted of a secondary
cell or a capacitor provided between the cathode 61 and the anode
62.
[0064] In this case, a space section 64 is provided outside the
cathode 61. Hydrogen and water are supplied into the space section
64 via the separation section 66, and thus hydrogen and water reach
the cathode 61. Another space section 65 is provided outside the
anode 62. Oxygen taken in from the atmosphere via the micro pump is
supplied into the space section 65, and thus oxygen is supplied to
the anode 62.
[0065] Hydrogen ions (proton; H.sup.+) in which electrons (e.sup.-)
are separated from hydrogen are produced on a side of the cathode
61 as shown in the following equation (4), and pass to a side of
the anode 62 via the ion conductive film 63, and then the cathode
61 takes out electrons (e.sup.-) therefrom to allow a current to
flow.
H.sub.2.fwdarw.2H.sup.++2e.sup.- (4)
[0066] On the other hand, electrons (e.sup.-) supplied by way of
the charging section 6, hydrogen ions (H+) which have passed
through the ion conductive film 63, and oxygen cause a reaction on
the side of the anode 62, thereby producing by-product water, as
shown in the following equation (5).
2H.sup.++(1/2)O.sub.2+2.sup.e-.fwdarw.H.sub.2O (5)
[0067] The series of electrochemical reactions described above
(equation (4) and equation (5)) proceed under an environment at a
relatively low temperature of about room temperature to 80.degree.
C., and water is basically the only by-product except for electric
power. The electric power generated by the fuel cell section 5 is
supplied to the charging section 6, whereby the charging section 6
is charged. Water as the by-product produced by the fuel cell
section 5 is once taken in by a by-product take-in section 107, and
is subsequently collected by a by-product collecting section 109 in
a fuel storage module 102 described later. The by-product take-in
section 107 may supply a proper amount of taken-in water to the
reforming reaction section 8 and the carbon monoxide elimination
section 9 as necessary.
[0068] Here, in the micro chemical reactor 4 having the above
configuration, the first to third substrates 12 to 14 that are
laminated on each other are accommodated in the first and second
outer panels 15 and 16 that are joined to each other, which makes
it possible to save space and design the size and shape of the fuel
cell system 1 itself to correspond to the size and shape of
multipurpose chemical cells such as dry cells.
[0069] In the embodiment described above, the case where the thin
film heater 11 is used as part of the heat source has been
described, which is not limited. For example, another embodiment of
this invention shown in FIG. 9 and FIG. 10 may be applied. FIG. 9
is a cross sectional view similar to FIG. 3 showing the essential
parts of the micro chemical reactor as another embodiment of this
invention, and FIG. 10 is a transmitted plan view of a part
corresponding to a fourth substrate 71.
[0070] In this case, the fourth substrate 71 is provided between
the first substrate 12 and the second substrate 13. The thin film
heater is not provided in the central part of the surface of the
second substrate 13 opposite to the fourth substrate 71. Instead, a
thermal fluid flow path groove 67 is cut in the central part of the
surface of the fourth substrate 71 opposite to the second substrate
13. The thermal fluid flow path groove 67 and the second substrate
13 are combined with each other to form a thermal fluid flow path
72. The thermal fluid flow path 72 is provided meanderingly,
similarly to the reforming flow path 42 and the combustion flow
path 76. An inflow side flow path 73 is provided in the thermal
fluid flow path groove 67 on an inflow side of the thermal fluid
flow path 72, and an outflow side flow path 74 is provided in the
thermal fluid flow path groove 67 on an outflow side.
[0071] An inflow side end of the inflow side flow path 73 is
disposed at such a position that it does not overlap the terminal
end of the vaporization flow path 41 shown in FIG. 4, and is
connected to one end of a thermal fluid supply tubule that is
inserted into the round transmitting hole provided at predetermined
portions of the first outer panel 15 and the first substrate 12,
which is not shown in the drawing. An outflow side end of the
outflow side flow path 74 is disposed at such a position that it
does not overlap the starting end of the carbon monoxide
elimination flow path 43 shown in FIG. 4, and is connected to one
end of a thermal fluid discharge tubule that is inserted into the
round transmitting hole provided at other predetermined portions of
the first outer panel 15 and the first substrate 12, which is not
shown in the drawing.
[0072] The other end of the thermal fluid supply tubule and the
other end of the thermal fluid discharge tubule are connected to
both ends of a thermal fluid circuit having a micro pump and a
heater provided outside the micro chemical reactor 4, which is not
shown in the drawing. Then, liquid such as silicon oil or gases
such as water vapor, air and nitrogen are supplied as the thermal
fluid into the thermal fluid flow path 72, and the vaporization
flow path 41. The reforming flow path 42 and the carbon monoxide
elimination flow path 43 are heated with heat energy obtained from
the supplied thermal fluid. However, also in this case, heating is
carried out mainly with the heat energy generated by the combustion
through a catalyst combustion reaction in the combustion flow path
76 of the combustion section 10. The heat energy from the thermal
fluid is used for secondary heating. The thermal fluid stores the
heat energy of the combustion section 10 and circulates in the
thermal fluid flow path 72 as necessary.
[0073] In the embodiment described above, the grooves are
respectively provided in the first substrate 12 and the third
substrate 14 to form the flow paths, but as shown in FIG. 11, the
vaporization flow path groove 57, the reforming flow path groove 58
and the carbon monoxide elimination flow path groove 59 that are
continuously formed in one surface of the second substrate 13, and
the first substrate 12 which covers those grooves, may constitute
the vaporization flow path 41 of the generation fuel vaporization
section 7, the reforming flow path 42 of the reforming reaction
section 8 and the carbon monoxide elimination flow path 43 of the
carbon monoxide elimination section 9, respectively. Further, the
combustion fuel vaporization flow path groove 51, the combustion
flow path groove 52 and the discharge flow path groove 53 that are
continuously formed in the other surface of the second substrate
13, and the third substrate 14 which covers those grooves, may
constitute the combustion fuel vaporization flow path 75, the
combustion flow path 76, and the discharge flow path 77
respectively.
[0074] FIG. 11 is a cross sectional view along a line similar to
the line III-III of FIG. 2, in which the generation fuel supply
tubule 21, the oxygen supply tubule 23, the combustion fuel supply
tubule 27, the electrodes 33 and the discharge flow path 77 are not
illustrated. The second substrate 13 is a silicon substrate with
excellent workability and relatively high thermal conductivity, and
the first substrate 12 and the third substrate 14 which are on and
under the second substrate 13 are made of glass whose thermal
conductivity is lower than that of the silicon substrate, and thus
the vaporization flow path 41, the reforming flow path 42 and the
carbon monoxide elimination flow path 43 can have a configuration
that is easy to heat and capable of storing heat so that the heat
is not extremely generated outside. The reforming catalyst layer 44
and the selective oxidative catalyst layer 45 have been formed on
three surfaces of the groove, but may be formed on at least one
surface or more.
[0075] In the embodiments described above, the carbon monoxide
elimination section 9 oxidizes carbon monoxide in accordance with
the above equation (3), but may oxidize it by an aqueous shift
reaction represented by the following equation (6), and the carbon
monoxide elimination flow path 43 may be provided with both parts
where the chemical reactions of equation (6) and the equation (3)
are caused.
CO+H.sub.2O.fwdarw.CO.sub.2+H.sub.2 (6)
[0076] Water, which causes the aqueous shift of carbon monoxide, on
a left side of the equation (6) is contained in the generation fuel
section 2, and water which has not reacted in the above equation
(2) may be used, and water taken in by the by-product take-in
section 107 from the fuel cell section 5 may also be used. Since
the reaction of the equation (6) produces hydrogen, an amount of
hydrogen supplied to the fuel cell section 5 can be increased, so
that the part which causes the reaction of the equation (6) should
preferably be provided closer to a side of the reforming flow path
42 than the part which causes the reaction of the equation (3).
[0077] In the embodiments described above, the slits 56 are
continuously provided in the first substrate 12, the second
substrate 13 and the third substrate 14, but in order to improve
strength, the slits provided side by side with each other in the
first substrate 12, the second substrate 13 and the third substrate
14 may be displaced to be arranged in such a manner that they do
not overlap each other.
[0078] FIG. 12 is a perspective view of the partially broken fuel
cell system 1 comprising the compact chemical reactor and fuel cell
of the present invention.
[0079] As shown in FIG. 12, the fuel cell system 1 comprises a fuel
storage module 102 which stores the generation fuel 68 to be
reformed and the combustion fuel 69 to be combusted, and a power
generation module 103 which has the built-in micro chemical reactor
4 to generate electricity using the generation fuel 68 stored in
the fuel storage module 102. The micro chemical reactor 4 has the
generation fuel vaporization section 7, the reforming reaction
section 8, the carbon monoxide elimination section 9, the
combustion section 10, the thin film heater section 11, the first
micro pump 46 and the second micro pump 47.
[0080] The fuel storage module 102 has a substantially cylindrical
case 104. The case 104 can be detachably attached to the power
generation module 103. A round through-hole 105 is formed at a head
top portion of the case 104, and a first drain pipe 106 which
allows by-product water produced by the power generation module 103
to flow is formed in an inner part of an outer periphery of the
case 104. The by-product collecting section 109 which stores water
to be drained is disposed at a bottom of the fuel storage module
102. The by-product collecting section 109 is connected to a first
drain pipe 106.
[0081] A fuel package 108 is detachably housed inside the case 104,
and part of an outer peripheral surface of the fuel package 108 is
exposed from the outside of the case 104. The fuel package 108
further has the generation fuel section 2 in which the generation
fuel 68 is sealed and the combustion fuel section 3 in which the
combustion fuel 69 is sealed. The fuel package 108 is a transparent
or semitransparent columnar member having an internal space, and is
made of a biodegradable material degraded by bacteria or the like.
As part of the fuel package 108 is exposed and the fuel package 108
is transparent or semitransparent, it is possible to easily check
the presence and remaining amount of the generation fuel 68 and the
combustion fuel 69 inside through the fuel package 108.
[0082] The generation fuel 68 is a mixture of a liquid chemical
fuel and water, and alcohols such as methanol and ethanol or carbon
compounds containing a hydrogen element, for example, ethers such
as diethyl ether and gasoline are applicable as the chemical fuel.
In the present embodiment, a mixture in which methanol and water
are mixed is used as the generation fuel 68.
[0083] The combustion fuel 69 is a liquid chemical fuel, and
alcohols such as methanol and ethanol or carbon compounds
containing a hydrogen element, for example, ethers such as diethyl
ether and gasoline are applicable as the chemical fuel. In the
present embodiment, a high concentration of methanol is used as the
combustion fuel 69.
[0084] A partition plate 111 which separates the generation fuel 68
from the combustion fuel 69 is formed inside the fuel package 108.
A supply port 110 for supplying the generation fuel 68 and the
combustion fuel 69 to the power generation module 103 is provided
at the head top portion of the fuel package 108 in a manner to
protrude to be inserted into the through-hole 105 of the case
104.
[0085] A supply pipe 112 extending in upward and downward
directions of FIG. 12 to be inserted in the supply port 110 is
provided inside the fuel package 108. The supply pipe 112 extends
from the bottom of the fuel package 108 to an edge of the supply
port 110. Since the supply pipe 112 is divided into small parts by
the partition plate 111, the generation fuel 68 between the supply
pipe 112 and the partition plate 111 moves upward by a capillary
phenomenon to reach the first micro pump 46. The combustion fuel 69
between the supply pipe 112 and the partition plate 111 moves
upward by the capillary phenomenon to reach the second micro pump
47.
[0086] A sealing film is provided inside the supply port 110, which
closes the entire supply port 110 so that the generation fuel 68
and the combustion fuel 69 do not leak in a state where intake
nipple portions 137, 138 of the power generation module 103 are not
inserted, but the intake nipple portions 137, 138 of the power
generation module 103 are inserted into the supply port 110 in
order to break the sealing film, and the intake nipple portions
137, 138 communicate with the fuel package 108 so that they can
take in the generation fuel 68 and the combustion fuel 69,
respectively.
[0087] The power generation module 103 includes an almost
cylindrical case 130. The micro chemical reactor 4 is disposed
inside the case 130. The fuel cell section 5 is disposed on a
periphery of the micro chemical reactor 4 and on an outer
peripheral side of the case 130. A by-product take-in section 135
takes in part of the by-product produced by the fuel cell section 5
and supplies this to the micro chemical reactor 4 as necessary. The
control circuit section 20 electrically controls those above.
[0088] A plurality of slits 131 for supplying oxygen in the air
outside the power generation module 103 that is needed for power
generation by the fuel cell section 5 to the fuel cell section 5 is
formed in a state arranged in parallel with each other outside the
fuel cell section 5 and in an outer peripheral surface of the case
130.
[0089] A terminal 132 for supplying electric energy generated by
the fuel cell section 5 to an external device is provided at the
head top portion of the case 130. A plurality of air holes 133 for
taking in oxygen necessary for the combustion section 10 of the
micro chemical reactor 4 to combust the combustion fuel 69 as well
as oxygen necessary for the carbon monoxide elimination section 9
to oxidize carbon monoxide and for discharging carbon dioxide
produced by the micro chemical reactor 4 are formed on a periphery
of the terminal 132 and at the head top portion of the case
130.
[0090] A second drain pipe 134 is provided on the outer peripheral
side of the case 130. The second drain pipe 134 has a convex shape
whose edge protrudes downward from the bottom of the case 130, and
the convex portion can be received in a corresponding concave part
in the first drain pipe 106 of the fuel storage module 102. The
second drain pipe 134 is a pipe for allowing by-product water
produced by the fuel cell section 5 to be distributed. The
by-product water is discharged to the by-product take-in section
135 through the second drain pipe 134 and the first drain pipe
106.
[0091] The second drain pipe 134 is coupled to the by-product
take-in section 135. A water introduction pipe 136 provided in the
case 130 leads to the second drain pipe 134 via the by-product
take-in section 135. The by-product take-in section 135 functions
as a pump which introduces the by-product water produced by the
fuel cell section 5 to the micro chemical reactor 4 as necessary,
and supplies a proper amount of water intended for the micro
chemical reactor 4 to the water introduction pipe 136, and then
discharges extra water to the second drain pipe 134. The sections
requiring water in the micro chemical reactor 4 include the
reforming reaction section 8 which causes the reforming reaction of
the above equation (2) and the carbon monoxide elimination section
9 which causes the aqueous shift reaction of the above equation
(6). The micro chemical reactor 4 reuses water thus produced in the
fuel cell system 1, thereby making it possible to heighten the
concentration of chemical fuel except for water contained in the
generation fuel 68 in the generation fuel section 2 of the fuel
package 108, and increase an amount of produced hydrogen per unit
volume of the fuel, and also increase output of the fuel cell
section 5 per unit volume of the fuel.
[0092] In the fuel storage module 102 and the power generation
module 103 as described above, when the fuel storage module 102
storing the fuel package 108 is attached to the power generation
module 103, the second drain pipe 134 of the power generation
module 103 is connected to the first drain pipe 106 of the fuel
storage module 102 on an outer peripheral side of an area where the
modules 102, 103 are connected. In this way, the second drain pipe
134 communicates with the first drain pipe 106, thereby making it
possible to let the by-product water produced by the power
generation module 103 flow from the second drain pipe 134 to the
first drain pipe 106 to be discharged to the by-product take-in
section 135.
[0093] The fuel applied to the fuel-reforming type fuel cell
presently under research and development may be a fuel which is at
least a liquid fuel or liquefied fuel or gas fuel containing
hydrogen elements and from which electric energy can be generated
by the fuel cell section 5 at a relatively high energy conversion
efficiency, and fluid fuels that can be satisfactorily applied
include alcoholic liquid fuels such as ethanol and butanol in
addition to methanol mentioned above, liquid fuels made of
hydrocarbons which are vaporized at ordinary temperature and at
atmospheric pressure, for example, liquefied gases such as dimethyl
ether, isobutane and natural gas (CNG), or a gas fuel such as a
hydrogen gas.
[0094] As described above, according to this invention, the flow
paths are provided inside the flow path structure and the flow
paths are constituted of a plurality of continued parts where
different chemical reactions take place, so that a plurality of
chemical reactions can be efficiently caused continuously in plural
kinds of flow paths, and the whole reactor can be made simple and
compact.
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