JPS58129780A - Fused carbonate fuel cell layer body - Google Patents

Abstract

PURPOSE:To maintain temperature distribution in a plane direction of a fuel cell body, an anode without complicating a fuel gas passage, by installing a modified layer, which carries out modifying reaction on methanol fuel, inside the fuel cell. CONSTITUTION:An oxidizer gas recycle device 37, a fuel gas recycle device 36, an exhaust fuel gas combustion burner 39 as well as a feed pump 41 and a DC load device 40 are all disposed around a fuel cell body 38 and, using water 33, methanol 34 and air 35, a fused carbonate fuel cell of 10kW in rated output is operated. At this time, a mixed solution of methanol and water is led into a bent pipe 29 installed on the outer surface of a gas distributor 31b at the fuel gas exhaust side by means of an intake pump 26 and gasified hereat whereby modified by a methanol modified layer 27 of a CuO-Cr2O3 clad nickel porous layer installed inside a gas distributor 31a at the fuel gas exhaust side and then fed to the anode side of each individual cell of the fuel cell layer body.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] i. The present invention relates to a φ fused acid salt fuel cell, and particularly relates to the use of alcohol such as methanol as the fuel and its reforming [prior art and its problems; Requirements] The battery power generation system converts methane and water vapor into hydrogen and
It was reformed into a mixed gas containing carbon oxide as the main component, which was then supplied to the fuel cell itself. However, this method of configuring a power plant using a reformer installed outside the methanol reforming fuel cell main body has the following drawbacks.

■ Since the entire reformer is required separately, the area required per unit cage air output of the power plant increases.

(2) Since the methanol reformer has an optimal size and thermal efficiency depending on the amount of reformed fuel, it is necessary to change the size depending on the scale of the permeation output of the power plant. In particular, in order to carry out the entire reforming reaction with a thermal efficiency of more than 90%, the throughput must be IM.
A reformer of a scale equivalent to the electrical output of the W and older models is required.

■ Piping is required to transfer the reformed fuel gas from the reformer to the fuel cell, and this piping must be insulated to be able to transfer high-temperature gas.

As a method to overcome all of these drawbacks, a method of reforming the fuel gas inside the fuel cell is proposed in Japanese Patent Laid-Open No. 12700/1983. Figures 1 and 2 are JP-A-55-1
This is described in Japanese Patent No. 2700. In FIG. 1, a fuel cell single cell 1 is composed of an anode 2, an electrolyte layer 3, and a cathode 4V (thus).Adjacent fuel cell single cells 1 are separated by a separator 5.

As shown in FIG. 2, this separator 5 is provided with a groove-shaped oxidant gas flow path 6 on one side for supplying an oxidant to the cathode 4, and on the other side, Anode 2
A wave-shaped reformed gas flow path 7a is provided for supplying fuel to the fuel. This reformed gas flow path 7a is created by attaching a corrugated sheet member 8 to the separator plate 5. In addition, a reforming catalyst 9 (for example, a catalyst such as OuO-ZnO is used) is filled in the fuel gas flow edge 7b of the corrugated/-human member that is not in contact with the anode electrode.

A fuel cell device having such a configuration has an alcohol in the H2K fuel gas flow path 7b required on the anode side.
It can be obtained from fuel supplied in the form of υ etc. by the following reaction.

OH, OH+ H20→Co2+3H2However,
In a configuration in which the reforming reaction layer is provided only in the vicinity of the electromotive element, such as providing the reforming catalyst in the fuel gas flow path 7b that does not contact the anode electrode of the corrugated sheet member 8, the amount of heat removed due to the reforming reaction is reduced, especially at low loads. If it is too large, the temperature near the unreformed gas inlet becomes too low, making it difficult to maintain a uniform temperature distribution in the planar direction of the anode of the fuel cell main body. This temperature non-uniformity is
This causes stress within the fuel cell due to the difference in thermal expansion, leading to the destruction of the airtight area.

In addition, in order to fully distribute gases of different compositions, such as fuel gas and reformed gas, to the front and back sides of the corrugated sheet members of each stacked battery, fuel gas (unused gas) is installed inside the VCU, for example, a gas distributor for exhaust gas. The gas flow path structure becomes complicated, such as by providing a passage for supplying (reformed gas) to the portion of each unit cell corrugated sheet where the modification reaction takes place.

[Object of the present invention]

In view of the shortcomings of the prior art, it is an object of the present invention to provide a method that does not make the fuel gas flow path structure particularly complicated and maintains a uniform temperature distribution in the planar direction of the anode of the fuel cell body during low load. The goal is to provide the carcass.

[Summary of the invention]

The present invention provides a reforming layer for carrying out the entire reforming reaction of methanol fuel in the space between the fuel gas inlet of the gas distributor provided on the side of the fuel cell stack and each cell in the stack. This is an acid-acid fuel cell stack that complicates the flow path structure.

[Embodiments of the invention]

Embodiments of the present invention will be described using the drawings. 3 is a vertical sectional view thereof, and FIG. 4 is a plan view taken in the direction of arrow A in FIG. 3, showing the third fuel cell stack. FIG. 6 is a perspective view of the main body in which the unit cells used in FIG. 3 are stacked, and FIG. 6th
The illustrated unit cell 20't 100 layers, manganese-nickel alloy aggregates 21a, 21b, alumina insulating plates 22a, 22b, and stainless steel reinforcing plate 23
a, 23b, and four stainless steel tightening bars 24a
, VH for 24b and 4 tightening rods 25, height 870
0mm, width and depth are both 300mm, rated output 10KW
The main body 38 inside the fuel cell stack was constructed. Then,
A space 40 with a methanol steam mixed gas inlet 26a above and a recycled fuel gas inlet 26b at the bottom with a space 40a provided with the methanol steam mixed gas inlet 26a on the inside and a recycled fuel gas inlet 26b provided therewith.
b 'i Thickness 40 so as to divide the internal space into two
0uO-C on 1m surface! r20. A gas distributor 31a on the fuel gas supply side has a methanol reforming layer 27 made of a porous sintered body covered with nirakpy, and a spent fuel gas discharge port 30fc at the bottom, and a bent stainless steel pipe 29 on the outer surface. A fuel gas discharge side gas distributor 31b which is welded into a methanol/water mixed liquid vaporizer 41, and gas distributors (not shown) on the oxidant gas supply side and discharge side are attached, and the outside is covered with a heat insulating layer to form a fuel cell stack. was constructed. Further, one end of the bent stainless steel pipe 29 is connected to the methanol steam mixed gas inlet 26a, and the other end is connected to the discharge side of the methanol and water mixed liquid introduction pump 32.
The inlet of 2 is connected to methanol and water sources. Furthermore, as shown in FIG. 5, an oxidizing gas recycling device 37, a fuel waste recycling device 36, an exhaust fuel gas combustion burner 39, a supply pump 41. The DC load device 40 was used to operate the fuel cell 8f. At this time, the mixed liquid of methanol and water is introduced by the introduction pump 26 into a bent vibrator 29 provided on the outer surface of the fuel gas discharge side gas distributor 31b, where it is vaporized, and is vaporized there. The structure of a single fuel pond used for the acid pond carcass layer body modified with the methanol reforming layer 27 of a porous nickel coated with 0uO-Or203 will be described.
Using an alloy powder of wt%Ni and 10wt%Or,
It is sintered in a reducing atmosphere using carpoquin methyl sevulose as a binder so as to have grooves 51a on one side through which fuel gas flows, and has a porosity of 60% and a total thickness of 1.5 m.
m, groove depth O, 13 mm, length and width 300 mm.

This anode 51 was wrapped in a stainless steel plate having a thickness of 0.2 tnm and having claws 52a and 52b around the periphery, and this plate was used as an anode side separator 52 for preventing mixing of fuel gas and oxidizing gas. In addition, a cathode side separator 53 made of a corrugated stainless steel plate with a thickness of d0.2 mm with both ends bent and having a cathode 54 loading recess 531) on two sides,
Convex portions 53a f on the side not in contact with the cathode 54: were electron beam welded to the anode side separator 52 to completely integrate the cathode side separator 53 and the anode side separator 52. The cathode 54 is made of nickel fiber with a thickness of 300 mm.
After forming a mat of 280 mm x 0.5 mm thick, it was made into a trivalent oxide in an alkaline aqueous solution, dried, and treated in a mixed solution of propylene carbonate and lithium persalt oxide. surface (i7Li
A divalent nickel oxide with diffused ions was loaded in the recess of the cathode side separator 53. The electrolyte layer 55 is made of boron nitride short fibers, diameter 3μ, length 0.2mm, as a reinforcing material, mixed with β-type lithium aluminate and a binder in a weight ratio of 15:80:5. After forming the sheet 55a with a thickness of 0.5 mm, this 7) i of 55a is placed between the sheet 55a and the anode 51.
The electrolyte 55b of a mixed powder of 00° was applied to Li2Co at a molar ratio of 62:38 and 3 times the weight of t.

〔Effect of the invention〕

By adopting the configuration of the present invention, the following effects were obtained.

■ Compared to conventional fuel cell stacks, the total weight of the gas distributor on the fuel gas supply side is increased by 15%, and the total weight of the gas distributor on the fuel gas discharge side is increased by 10%, but the structure of the internal structure and The fuel gas can be reformed in the fuel cell 8f without changing the external shape, that is, without significantly changing the structure of the stacked body, and there is no need for a large-scale external reformer.

■ We were also able to carry out a relatively small-scale reforming reaction with an air output of 10 KW.

■ When operating at 20% of the rated ventilation output and the rated fuel flow rate of 3096, the temperature distribution of the anode of the conventional fuel cell stack is ±50°C, while the temperature distribution of the present invention is ±20°C.
It became 00.

□ ■ The temperature of the gas distributor outer wall is 300 to 400°C, which is 100 to 200°C lower than that of a conventional fuel cell stack.
We were able to reduce it by 30% from 00 m711. The fuel cell 8f layer body can be configured compactly.

■ The reforming layer in the distributor simultaneously acts as a gas flow baffle, making it possible to make the gas flow rate distribution uniform to the cells in each year of the fuel cell stack.

[Modified example of the invention]

Ribbed porous anode 51'e in FIG. 6, and a region 60aq with large pores on the electrolyte layer side, as shown in cross section in FIG.
A catalyst layer 60d of OuO-0r2o3 is formed in order to form a double structure of a region 60b with a smaller pore diameter on the side of the groove 60c through which fuel gas flows, and to cause a reforming reaction on the inner surface of the groove 60a. If it is formed as a ribbed porous anode 60, the thickness of the nickel porous sintered modified layer 27 coated with 20 g of OuO-Or provided inside the fuel gas supply side gas distributor 31a shown in FIG. 20 out of 40 friends
It can be reduced to mM.

At this time, when a fuel cell rated for 10KW was operated at a flow rate of 30% of the rated value to achieve the full output of the 20th section of the rated value, 90% of the vaporized methanol was reformed in the reforming layer installed in the distributor. Ta. On the other hand, when operated at the rated output, 50% of the vaporized methanol was reformed in the reforming layer in the gas distributor, and the rest was reformed in the ribbed porous anode polarization. In this configuration, the embodiment configuration VC shown in FIG.
When operating at a constant current of 50mA/m”, the production Rib
It was possible to increase the tonic pressure by 0.03V per cell. This is because when operating near the rated capacity, some of the fuel gas can be supplied as vaporized methanol to the vicinity of the center of the anode, so that the reaction occurs uniformly.

Furthermore, the combination of anode 51 and electrolyte 55 shown in FIG. 6 can be replaced with the structure shown in FIG. 8. That is, in FIG. 8, 70 uses two types of 5rTiO fine powder with different particle sizes, and has a region 70a with a large pore diameter, a region 70b with a small pore diameter, and a groove 70c in a portion with a large pore diameter. A ceramic porous ceramic whose entire surface 70d near the area 70c where the grooves 70c and f are to be formed is coated with Ni metal is fired as shown in FIG. It is a board. During assembly, an electrolyte of a mixed powder of Li, 003, and 2Co3 is applied to the t-plane 70e on the side of the small-pore area 70b, and the electrolyte is melted by heating during the first battery startup, and the liquid is applied to the small-pore area 70b. The electrolyte is retained in the porous substrate 70+ by impregnation.

Q, it is also possible to use ethanol n=f in addition to methanol as a fuel.

The place where the mixed liquid of methanol and water is completely vaporized is not limited to the outer wall surface of the gas distributor on the fuel gas discharge side, but it is also possible to use the outer wall surface of another gas distributor.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view showing the main body of a stacked body of a conventional fuel reformer built-in fuel delivery device, Fig. 2 is a longitudinal cross-sectional view showing the flow side of Fig. Plan view showing the view in the direction of arrow A, 5th
The figure is a block diagram of a magnetization system using the integrated fuel cell stack I shown in Figure 3, Figure 6 is a perspective view of the main body constituting the stacked body shown in Figure 3, and Figures 7 and 8 are 020... Cell 27... Methanol reforming layer 29... Pipes 31a, 31b... Gas distributor j8... Main body 41...methanol, water mixed liquid vaporizer 51...anode 52...anode side separator 53...cathode side separator 54...cathode 55...electrolyte layer agent Patent attorney rule Yu (and 1 other person) 6th
Figure 33I:) Figure 7 Figure 8, 7De 'toc'7oc

Claims (1)

[Claims] A vaporizer installed in a gas distributor attached to a side wall that vaporizes arcuate fuel into fuel gas, and a space divided into two spaces inside the gas distributor on the fuel gas inlet side and on the cell side. A porous methanol reforming cell stack that reforms the fuel gas to be split.