JPH03216962A - Fuel cell - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field 1] The present invention is directed to the application of chemist's energy to electrical energy.
This relates to fuel cells used in the sector that is being converted to fuel cells.

[Prior art] The molten carbonate fuel cell, which is one of the fuel cells that has been proposed to date, uses a tile (electrolyte plate) that is impregnated with molten carbonate as an electrolytic material into a porous material, and is used as a cathode. (acid electrode) and an anode (fuel electrode), supply oxidizing gas to the cathode side, and supply fuel gas to the anode side. One cell is one in which power is generated by the electric potential difference between the two cells, and each cell is laminated in multiple layers with separators interposed therebetween to form a stack.

The fuel gas supplied to the anode of such a fuel cell is either a reformed raw material gas such as natural gas that has been reformed in a reformer, or a reformer that functions as a reformer is installed in the fuel cell stack. A so-called internal reforming type fuel cell has also been proposed, which is equipped with a fuel cell to perform reforming within the fuel cell.

As an example, as shown in Figures 7 and 8, tile 1
When a cell C sandwiched between a cathode 2 and an anode 3 from both sides is laminated via a separator 4 to form a stack, a Li/I 4 type is used for the anode 3, and the cell C is formed between the ribs 3a. The groove is used as a passage 5 for fuel gas, this passage 5 is filled with a reforming catalyst* (alumina carrier 10Ni>6), and the passage 5 is filled with gas + water vapor (for example, C}l.+H20) and oxidizing gas OG to the gas passage 7 on the cathode side formed by the hibarator 4, a reforming reaction occurs on the anode 3 side and a reaction occurs between the anode 3 and the cathode 2. The electrochemistry test and the electrochemistry test are carried out at the same time.

In the internal reforming type fuel cell described in 1-1, the reforming reaction and the electrochemical reaction are simultaneously generated, and in such a coexisting reaction, the water cord and the oxidized carbon cord are consumed. The reforming reaction is determined by the methane conversion rate determined in a chemical equilibrium wetland.
Therefore, a high methane conversion rate can be achieved at low temperatures.Also, electrochemical reactions are exothermic reactions, while reforming reactions are endothermic reactions, so if operated while maintaining balance,
The benefits of high power generation efficiency are obvious.

[Problem 1 that the invention seeks to solve] However, in the above-mentioned internal reforming type fuel cell, the activity of the reforming catalyst decreases by ↑1 due to the electrolyte, and the life of the reforming catalyst decreases. There is a drawback that it becomes χ0. In order to address this drawback, a complete gap between the electrolyte plate and the reforming section is provided.
Insert the cutting plate and carefully scrape it so that it does not go towards the electrolyte or catalyst.This is the so-called indirect internal reforming method.

This has the advantage of preventing the deterioration of the reforming catalyst due to electrolysis, and allowing a portion of the reaction heat of the battery to be used as a heat source for reforming. However, unlike a normal reformer, the fuel is burned in the combustion chamber and the heat is absorbed into the reforming chamber for reaction. Instead, it uses fuel for heating to maintain the operating temperature of the fuel cell. Since the operating temperature of the reforming section is different from that of the reforming section, there is a problem that the reforming rate is low as a result of being limited by the operating temperature of the reforming section or the operating temperature of the combustion battery.

Once the continuous heating is determined, the reforming rate in i is limited by the following equation from the equilibrium constant determined thermodynamically.Kρ: Equilibrium constant C Number Co: 7 number of CO + -1, : - number of H2 M: total number P: ft, constant/t fJζ - In order to increase the reforming rate, Is there any other way than to increase the operating temperature?-1 In the case of an internal reforming type fuel cell, the operating temperature of the fuel cell is determined, so if the reforming rate is bad, it was decided that -τ should not be worked on.

The present invention improves the reforming rate by supplying reformed Mizuki gas from the reforming section to the connected anode in a fuel cell having a reforming section in the fuel cell stack. There is something to cover to raise the level.

Fi. ! 4! [Means for Solving the Problems] In order to solve the above problems, the present invention sandwiches both sides of a tile between cathode and anode electrodes, and supplies oxidizing gas to the cathode side and fuel gas to the anode side. A reforming chamber filled with a reforming catalyst and configured to flow reforming raw material gas is inserted into every few cells of the fuel cell stack, which is composed of stacked cells arranged to be supplied via a separator. The part of the reforming chamber in contact with the anode gas passage is configured with a hydrogen permeable membrane, and hydrogen in the gas generated in the reforming chamber can be supplied to the anode side through the hydrogen permeable membrane. It has a structure like this. In addition, a heat exchanger is installed outside the fuel cell stack to preheat the reformed raw material gas, and the heat transfer wall of the heat exchanger is made of a hydrogen permeable membrane, so that the gas is recycled in the reforming chamber and discharged. The reformed fuel gas is supplied through the heat exchanger to 7 nodes that are not in contact with the hydrogen permeable membrane of the reforming chamber, and when passing through the heat exchanger, the reformed raw material gas is passed through the hydrogen permeable membrane. -C At the same time as preheating, hydrogen gas is taken into the reforming raw material and supplied to the reforming chamber.

Furthermore, instead of the configuration in which a reforming chamber is inserted into each of the plurality of cells described above, the anode gas passage may be configured with a hydrogen-permeable membrane, and cells filled with a reforming catalyst in the anode gas passage may be replaced with normal cells. It may be stacked on the annotate side q and the hydrogen converted by reforming is supplied to the annot side l\\ through the hydrogen permeable membrane, or the 7note gas passage may be communicated between the inside and the outside,
It may also be configured such that a reforming catalyst is filled here and an aqueous permeable membrane is placed inside the anode gas passage.

``Function'' The J5 has a structure in which a reforming chamber is inserted into each cell to form an indirect internal reforming type fuel cell, and the part of the reforming chamber in contact with the 7/node gas passage is constructed with a hydrogen permeable membrane. In such cases, the operating temperature of the fuel cell may limit the amount of hydrogen (H2) in the gas produced in the reforming chamber.
) will be supplied to the annotate side via the hydrogen permeable membrane, so the 11, atomization in the generated gas in the reforming chamber will be reduced, and as a result, the reforming reaction equation CLL 1H2 0→CO+3N ? can be advanced from the k side to the 6th side to increase the modification rate. On the other hand, 1-
At the anode, water is produced by a reaction between hydrogen and carbonate ions that have been synthesized by the reaction on the cand side and have been pumped through the tile from the cathode side.

In the above-mentioned reforming chamber, the reforming reaction proceeds with the decrease of 1"2 concentration in the produced gas, increasing the reforming rate. However, near the input of the reformed raw material gas in the reforming chamber, Almost no progress yet.
(There are zones where there is no anode l＼
If the supply of water cable is interrupted, the current density of the fuel cell, 'IiA
It is also possible that a sleet causes an imbalance in the degree distribution,
Even in such a case, the fuel gas discharged from the reforming chamber is passed through a heat exchanger, hydrogen is contained in the reforming raw material gas through a hydrogen permeable membrane in the heat exchanger, and the hydrogen is introduced into the reforming chamber. By covering it, hydrogen is supplied to the 7 nodes even near the reforming chamber population, and the above-mentioned fear is eliminated.

[Implementation Example 1] Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show an embodiment of the present invention, in which a tile (electrolyte plate) 1 is sandwiched between a cathode (oxygen 44) 2 and an anode (fuel electrode) 3 from both sides. A fuel cell configured by stacking cells C in multiple layers via a zeparator 4, which supplies oxidizing gas (airman carbon dioxide) OG and also supplies fuel gas (I)2》FG to the anode 3 side. One stage of a flat plate type reforming chamber 8 is inserted into each classroom C of the stack S, and the reforming chamber 8 is filled with a reforming catalyst 9 and a j/node gas Contact with the passage η
The hydrogen permeable membrane 10 constitutes the portion.

h ■ Turning around, the second pallet 4 is the center plate 4a.
The cathode and anode gas passages 11. The configuration includes rugate plates 4b and 4C for forming 12, and seal plates 4d and 4e on the periphery, and a manifold for supplying and discharging oxidizing gas OG and fuel on one side and the side of the periphery. The structure is equipped with a manifold for supplying and discharging gas FG.

The reforming chamber 8 has a filling part 13 filled with a reforming catalyst 9 in the central part formed in one square by partition walls 14 and 15, and a reformed raw material header 16 on one end side and a reformed gas header on the other end. -17
and the partition wall 14. is connected through the packed portion 13 of the reforming catalyst 9. A large number of holes 18 are bored in the filling portion 15, and the reforming catalyst 9 is filled in the filling portion 13, and the anode gas passage 12 of the filling portion 13 of the reforming catalyst 9 is
A perforated plate 19 is used for the part in contact with the perforated plate 19, and a hydrogen permeable membrane 10 is placed inside the perforated plate 19, and a reforming reaction is carried out at the operating temperature of the fuel cell. It is supplied to the anode 3 through the water cable permeable membrane 10, and as shown in FIG. ] Open the second hold 21 for fuel gas release in the V1 reformed gas header 17.

In addition, gas is supplied to each cell C of the fuel cell stack S through the gas supply flow path υ1, and the cathode 2 of each cell C is supplied with oxidizing gas that has been passed through each oxidizing gas supply manifold. The oxidizing gas OG is supplied through the supply side flow path 22, and the gas discharged from the cathode 2 is discharged to the atmosphere through the cathode outlet [1 gas flow path 23] which is connected to the oxidizing gas exhaust manifold. Among the anodes 3 of each cell C, the anode 3 that is not in contact with the hydrogen permeable membrane 10 of the reforming chamber 8 is provided with a fuel gas supply side flow path 24 communicating with each fuel gas supply field manifold, The fuel gas 1G from the reforming chamber 8 is supplied through the heat exchanger 25, and the gas discharged from each anode 3 flows through the anode outlet gas passage 26. The gas discharged from the anode 3 in contact with the hydrogen permeable membrane 10 is passed through the heat exchanger 25 into the reforming raw material gas (natural gas + steam) supply channel 27, which is introduced into the reforming chamber. By merging the log gas through the log gas flow path 28, it flows into the reforming chamber 8 so as to be recycled.

Now, when the fuel cell starts operating and supplies preheated air and carbon dioxide to cathode 2 of each cell C, CO2 + 1/202
+28-- The reaction of CO3- occurs, and carbonate ions are produced.

On the other hand, in the reforming chamber 8, the reforming raw material gas, for example, CHJ
When 1H20 is supplied, the heat on the cathode 2 side causes a change in temperature (CHJ +t120-shiCO +3H,
) is carried out, and the generated gas σ month 2 is the hydrogen permeable membrane 1
0 and is supplied to the adjacent anode 3, so in the anode 3, it is generated on the cathode 2 side and the tile 1
Carbonate ions ( C
o]-") and [1, and the reaction GO]-+ hh→t"20 +CO2+2e will take place. 1- In the reforming chamber 8, since H2 is supplied to the annotate 3 through the hydrogen permeable membrane 10, the concentration of σ-12 in the generated gas is lowered, so that the above-mentioned reforming reaction is promoted. Hydrogen will be produced at a high reforming rate.

The fuel gas containing hydrogen produced in the reforming chamber 8 is transferred to the reforming chamber 8.
from the hydrogen permeable membrane 10 via the fuel gas supply side flow path 24.
On the other hand, the gas discharged from the annotate 3 which is in contact with the hydrogen permeable membrane 10 is directed toward the inlet side of the reforming chamber 8.

In the present invention, the portion of the reforming chamber 8 in contact with the 7-node gas passage 12 is configured with a hydrogen permeable PA10, and 11 in the gas generated in the reforming reaction is passed through the hydrogen permeable IQ1Q). 3, it is possible to reduce the amount of 112 liters in the produced gas in the reforming chamber 8 and promote the reforming reaction, thereby improving the reforming rate. .

Next, FIG. 4 shows an embodiment of the present invention.
As shown in the figure, part or all of the heat transfer partition wall of the heat exchanger 25 is constituted by a hydrogen permeable membrane 29, and the refrigerant gas is preheated by the fuel gas from the reforming chamber 8, and the hydrogen in the fuel gas is is transmitted through the water cable permeation rIIA29 and contained in the reforming raw material gas, and the reforming raw material gas containing hydrogen (+{2) is supplied to the reforming chamber 8. be.

According to this embodiment, 1"2 in the produced gas in the reforming chamber 8
is supplied to the ANOTE 3 to reduce the concentration of T12 and promote the reforming reaction υ, thereby increasing the reforming rate by -1. Since hydrogen is taken in, hydrogen is well supplied to the anode 3 even from near the entrance of the reforming chamber 8, and the anode 3
Toshisada will no longer be faced with a hydrogen supply shortage. If hydrogen is only being taken into the reforming raw material gas mentioned above, place J3 near the entrance of reforming chamber 8. There was a shortage of hydrogen supply to the fuel cell, causing an imbalance in the current density and temperature distribution of the fuel cell.
J3 can eliminate it. In addition, the above modification 1
When the hydrogen in the reforming raw material gas increases by introducing hydrogen into the reforming gas through the hydrogen permeable membrane 29, carbon precipitation is suppressed in the reforming reaction in the reforming chamber 8, and S/ of the reforming raw material gas increases. There is an advantage of being able to reduce the C (water vapor/charcoal) ratio. In addition, as hydrogen is taken into the reforming raw material gas, when a rapid reforming reaction occurs near 1 in the reforming chamber 8, the temperature in that part decreases by 1 or so, which is harmful to the fuel cell. Although this is an unfavorable situation, the presence of Mizuki (1'2) in the reforming raw material gas increases the fraction l1 of the 1F formation side gas, so the person u{=J
It can be said to be preferable in that respect as it suppresses reactions in the vicinity.

J3, in the fuel cell of the present invention described above, a flat reforming chamber 8 is inserted and arranged for every few cells of the fuel cell stack.
An example of indirect internal reforming is shown in which the portion 16 in contact with the anode gas passage of the reforming chamber 8 is constituted by a hydrogen permeable membrane 10. It can also be made into a mold.

Figures 5 and 6 both show examples of this.
The figure shows a cell C in which a tile 1 is held between both electrodes, a cathode 2 and an anode 3, and an oxidizing gas is supplied to the cathode 2 side, and a fuel gas is supplied to the anode 3 side. Passage 11 and anode gas passage 1
2 is formed on both sides with corrugated plates 31 and 32, and the anode gas passage 12 on the anode 3 side of the rail C of each stage is laminated via punch plates 33 and 34. "to form"
The Lugut plate 32 is made of a hydrogen permeable membrane and is made of hydrogen permeable tlU] Lugu 1 to 32a, and the continuous linear anode gas passage 12 formed by the Lugu 1" 32a made of the hydrogen permeable membrane is used for catalyst filling. Behind the space 12a,
The catalyst filling space 12a is filled with a reforming catalyst 35, and the hydrogen (H2) in the gas produced by the reforming reaction in the space filled with the reforming catalyst 35 is transferred to a hydrogen permeable membrane. 1-32a
from the anode gas passage 12 which is not filled with the reforming catalyst 35, H20 and CO2 generated by the reaction on the anode side are passed through and supplied to the anode 3.
The gas (fuel gas) reformed in the filling part of the reforming catalyst 35 is discharged from the anode 3 of the cell C which does not use a hydrogen permeable membrane in the corrugated plate 32.
It is designed to be supplied to the side.

The embodiment shown in FIG. 5 has the advantage that additional components such as the flat reforming chamber 8 in the embodiment shown in FIG. 1 can be eliminated, and the hydrogen permeation area can be increased. Furthermore, the modification rate can also be increased.

Further, in FIG. 6, cells C each consisting of a tile 1 sandwiched between the cathode 2 and an anode 3 electrodes from both sides are stacked together via a leverator 36, and each cell C is stacked with "noregu 1~" on the cathode 3 side. The plate 37 forms a gas passage 11 between the cathode 1 and the gas passage 11 with discontinuous irregularities and covers the inside and outside of the rug gate plates 1 to 37 so that they can freely come and go, and the annotate 3 side of each hill C. In the configuration in which similar anode gas passages 12 are formed by Rugou 1 and Play 1 to 38, hydrogen permeable F439 is arranged inside the Rugate plate 38. Then, the hydrogen permeable membrane 39 is placed along the outside of the anode 3 with the punch plate 34 in between, and the anode gas passage 12 formed by the corrugated plate 38 is opened.
A reforming catalyst 35 is filled in the fuel cell.

According to the embodiment shown in FIG. 6, 112 in the gas generated by the reforming catalyst 35 in the annot gas passage 12 filled with the reforming catalyst 35 passes through the hydrogen permeable membrane 39 and is supplied to the annot 3. The reforming rate in the reforming section is directed towards -L, while the reformed gas is transferred to the ANOTE 3 of ZEL C without the hydrogen permeable membrane 39.
In addition to being supplied to Toshisada as in the case of Figure 5.

A3. Needless to say, in the present invention, if nickel is used for the hydrogen permeable membrane, there is an advantage that the separator 4 does not need to be made of SUS and nickle.

[Effects of the Invention] As described above, according to the fuel cell of the present invention, the reforming chamber filled with a reforming catalyst is inserted into every few cells of the fuel cell stack, and the modification The part of the hydrogen chamber that contacts the anode gas passage is constructed with a hydrogen-permeable membrane, and even if the reforming reaction occurs at the operating temperature of the fuel cell, the hydrogen in the reformed gas is supplied to the anode through the hydrogen-permeable membrane. As a result, it is possible to reduce the degree of carbon dioxide in the produced gas in the reforming chamber and promote reforming, thereby improving the reforming rate without increasing the reaction temperature. In addition, by configuring part or all of the heat transfer partition wall of the heat exchanger that preheats the reformed raw material gas with the fuel gas reformed in the reforming chamber with a hydrogen permeable membrane, hydrogen can be avoided. Hydrogen in the fuel gas can be taken into the reforming raw material gas through the permeable membrane and barreled into the reforming chamber, so the amount of hydrogen near 8D {= J in the reforming chamber can be increased. Even in the zone near the person in the reforming room where the reforming reaction has barely progressed, it is possible to prevent a shortage of hydrogen supply to the anode and prevent the possibility of a shortage of hydrogen supply to the anode. It is possible to eliminate the problem of unbalance in current density and temperature of a certain fuel cell, and the increase in hydrogen in the reformed feed gas suppresses the precipitation in the reforming chamber. However, the S/C (steam/coal cable) ratio of the reforming raw material gas can be reduced.

In the past, the anode gas passage of the REL was formed with a hydrogen-permeable membrane Rug gate, and the reforming catalyst was filled in the outer gas passage. By having a configuration in which the outside is open and a hydrogen permeable membrane is placed inside, the hydrogen in the gas produced by the reforming reaction in the reforming section passes through the hydrogen permeable membrane (supplied to the ANOTE). Therefore, in addition to improving the reforming rate as described above, it is also possible to eliminate the need for additional components.

[Brief explanation of drawings]

Figure 3 is a sectional view taken from the direction ■ in Figure 2, Figure 4 is a schematic diagram showing another embodiment of the present invention, and Figures 5 and 6 are all related to the history of the present invention. FIG. 7 is a schematic view showing an example of a conventional internal reforming fuel cell; FIG. 8 is a perspective view showing an example of a conventional internal reforming fuel cell;
The figure is an enlarged view of the part ■ in FIG. 7. DESCRIPTION OF SYMBOLS 1... Tire, 2... Cathode, 3... Anode, 4... Leverator, 8... Reforming chamber, 9... Reforming catalyst, 10... Water cable permeable membrane, 12... Anode gas passage, 25... Heat exchanger, 29... Hydrogen permeable membrane, 30... Separator, 32a... Made of hydrogen permeable membrane."
Lugate, 35... Reforming catalyst, 39... Hydrogen permeable membrane, S... Fuel cell stack, C... Cell, OG...
... Oxidizing gas, [G... Fuel gas.

Claims (4)

[Claims] (1) A fuel cell constructed by stacking cells with a separator in between, in which both sides of a tile are sandwiched between cathode and anode electrodes, and oxidizing gas is supplied to the cathode side, and fuel gas is supplied to the anode side. A reforming chamber filled with a reforming catalyst and configured to allow reforming raw material gas to flow is inserted every few cells in the stack, and the portion of the reforming chamber in contact with the anode gas passage is covered with a hydrogen permeable membrane. so that hydrogen in the gas generated in the reforming chamber can be supplied to the anode through the hydrogen permeable membrane, and the fuel gas from the reforming chamber can be supplied to the anode of the cell that is not in contact with the hydrogen permeable membrane. A fuel cell characterized by having a configuration configured to supply fuel to a fuel cell. (2) The heat transfer partition wall of the heat exchanger that preheats the reforming raw material gas with the fuel gas from the reforming chamber is configured with a hydrogen permeable membrane, and the fuel gas preheats the reforming raw material gas and passes into the reforming raw material gas. 2. The fuel cell according to claim 1, wherein hydrogen is taken into the fuel gas. (3) A fuel cell constructed by stacking cells with a separator in between, in which both sides of a tile are sandwiched between cathode and anode electrodes, and oxidizing gas is supplied to the cathode side, and fuel gas is supplied to the anode side. Hydrogen permeable membrane corrugates are placed on the anode side of cells in any layer of the stack to alternately form anode gas passages and catalyst filling spaces, and the catalyst filling spaces are filled with a reforming catalyst. This allows the hydrogen in the gas reformed in the reforming catalyst filling section to be supplied to the anode through the hydrogen permeable membrane corrugate, and also allows the gas reformed in the reforming catalyst packing section to be supplied to the anode through the corrugated hydrogen permeable membrane. A fuel cell characterized in that the fuel cell is configured to supply fuel to an anode of the cell. (4) A fuel cell constructed by stacking cells with a separator in between, in which both sides of a tile are sandwiched between cathode and anode electrodes, and oxidizing gas is supplied to the cathode side, and fuel gas is supplied to the anode side. An anode gas passage in any cell of the stack is formed by a discontinuous corrugated plate so that gas can flow between the inside and outside, and the anode gas passage is filled with a reforming catalyst, and the anode gas passage of the anode gas passage is filled with a reforming catalyst. A fuel cell characterized by having a configuration in which a hydrogen permeable membrane is arranged on the side.