JPS6344931A - Fuel reforming apparatus - Google Patents

Abstract

PURPOSE:To reduce the pressure variation of the reforming gas supplied to a combustion battery, by providing a catalytic combustion device having the holes of combustion gas flow passages along the inner side wall of a case-shaped furnace body and embedding a vaporizer communicating with the outside in said combustion device. CONSTITUTION:When the high temp. exhaust gas from a fuel battery 1 passes a fuel supply pipe 31 and combustion air passes through a combustion air supply pipe 32 to flow in a catalytic combustion device 26, said gaseous mixture passes through a large number of holes 27. At this time, the gaseous mixture is oxidized and burnt on the inner wall surfaces of the holes 27 in the presence of the catalyst supported by the wall surfaces of the holes 27 to generate heat, and this heat is conducted through the molded body of the catalytic combustion device 26 to be transferred to the vaporizer 29 embedded in the molded body. As a result, the liquid fuel of the reforming raw material supplied to the vaporizer 29 to flow therethrough is vaporized to become raw material gas. The raw material gas is reformed to gas rich in hydrogen by a reforming device 7 to become reforming gas which is, in turn, supplied to the fuel battery 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a fuel reformer that is incorporated into a fuel cell power generation system and converts liquid fuel as a reforming raw material into hydrogen-rich reformed gas.

[Prior art and its problems]

The fuel supplied to the fuel cell is hydrogen, and the fuel used is a reformed gas obtained by reforming liquid fuel, which is a raw material for reforming, into hydrogen-rich residue using a fuel reformer. For this purpose, a fuel cell power generation system that combines a fuel reformer and a fuel cell is known.

FIG. 2 is a system diagram of a conventional fuel cell power generation system of this type. In the figure, l is a fuel chamber, 2 is a fuel tank containing liquid fuel such as alcohol, which is a raw material for reforming,
A fuel reformer f3 is interposed in the fuel supply line between the fuel tank 2 and the fuel cell 1. Such a fuel reformer 3 includes a vaporizer 6 for gasifying liquid fuel in a combustion chamber of a furnace vessel 5 equipped with a burner 4, and a reformer for reforming the fuel gas into hydrogen-rich gas through a catalytic reaction with a catalyst. 7, the off-gas discharged from the fuel cell 1 is supplied to the burner 4 and burned in the furnace, and the heat of the heat medium consisting of the insect-repelling flame and combustion gas is used in the vaporizer 6. The liquid fuel is vaporized to form a raw material gas, and this raw material gas is reformed in a reformer 7.

Note that 8 is a liquid fuel supply pump, and 9 is a blower that supplies air as an oxidant reaction gas to the fuel cell 1.

By the way, when operating a fuel cell, it is extremely important to keep the supply pressures of air as a reaction gas and fuel gas supplied to the fuel cell main body constant and balanced in order to prevent shortening of the life of the cell main body. That's true. For this purpose, it is necessary to always keep the supply pressure of the fuel gas supplied to the fuel cell main body through the fuel reformer of the fuel gas supply system constant.

Generally, when a liquid fuel is gasified, a large latent heat of vaporization is required, and the fuel undergoes a large volume change as it is gasified. On the other hand, if the configuration of the conventional reformer is maintained, in which the vaporizer 6 is simply piped into the combustion chamber of the furnace vessel 5 and the vaporizer 6 is heated by the heat of the combustion gas, the heat capacity of the vaporizer portion is comparatively low. The target is small. For this reason, it is difficult to constantly and stably replenish the large droplet heat of vaporization required for gasifying liquid fuel from the furnace side to the entire area of the vaporizer. The locations and regions where the fuel liquid is vaporized constantly fluctuate within the vaporizer, such as a local temperature drop due to deprivation of fuel, which causes the fuel gas delivered from the vaporizer outlet to change. Causes pressure fluctuations.

To this end, in the conventional fuel cell system, a throttle 10 is installed in the fuel scum supply system on the outlet side of the reformer 3 as shown in FIG. 2 to reduce pressure fluctuations in the fuel gas supplied to the fuel cell 1. A method has been adopted to reduce the size. However, this method of inserting the throttle 10 into the system significantly increases the pressure inside the reformer 3, which is not preferable in terms of pressure resistance. Another solution is the reformer 3.
A method has also been attempted in which a buffer tank (not shown) exclusively for reformed gas is installed between the fuel cell 1 and the fuel cell 1 to suppress fluctuations in the gas pressure supplied to the fuel cell 1; Installing a buffer tank has the disadvantage of increasing the size of the entire system.

In addition, a flame burner or a catalytic burner is used as the combustor in the fuel reformer as described above, but in either case, the burner is installed separately from the carburetor, so there is no possibility of turbulence in the flame or combustion gas from the burner. Since heat cannot be stably applied to the vaporizer due to the above-mentioned factors, there is also the drawback that pressure fluctuations are likely to occur due to the latent heat of vaporization of the liquid.

[Purpose of the invention]

In view of the above-mentioned points, the present invention stably vaporizes liquid fuel as a reforming raw material in a vaporizer by burning off gas discharged from a fuel cell, and reduces pressure fluctuations in the reformed gas supplied to the fuel cell. It is an object of the present invention to provide a fuel reformer that can reduce the amount of fuel.

[Summary of the invention]

According to the present invention, the above object is achieved by a fuel reformer that vaporizes reformed liquid fuel using a heat medium from a combustor to reform it into hydrogen-rich gas. a catalytic combustor having a hole for a combustion gas flow path, a vaporizer communicating with the outside is buried in the catalytic combustor, and a fuel supply pipe and a combustion air supply pipe are opened in an artificial region of the catalytic combustor, This is achieved by opening a combustion gas exhaust pipe in the outlet area.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view of a catalytic combustor and a carburetor of a fuel reformer according to an embodiment of the present invention. In the figure, the catalytic combustor 26
is arranged along the inner wall of the case-shaped furnace body I, and is provided with a large number of holes r whose surfaces support catalysts such as platinum in the direction of the inner wall, and further has holes 4 in which the inside of the vaporizer made of tubes can be buried. Multiple locations are provided in the same direction. Note that the catalytic combustor 26 having such holes γ and ends is made of a molded body of alumina or the like.

The tube of the vaporizer 29 is inserted into the hole of the catalytic combustor 26 and meandering, and the artificial tube 2L in the vaporizer and the outlet tube 29b pass through the case and communicate with the outside.

In the figure, the carburetor 29 is shown meandering in the vertical direction, but it may also be buried in a meandering manner in the horizontal direction or in a spiral shape. A fuel supply pipe 31 and a combustion air supply pipe 32 are provided which open in the inlet region of the catalytic combustor 26 and pass through the case, and a combustion air supply pipe 32 which connects to the furnace body. In addition, a combustion gas exhaust pipe is provided which opens at the outlet area of the catalytic combustor and discharges the combustion gas from the catalytic combustor, and the combustion gas discharged from this pipe is connected to the outlet pipe 29I of the carburetor 4. A reformer (not shown) filled with a reforming catalyst is heated.

With this configuration, high-temperature off-gas (reformed gas containing unreacted hydrogen) discharged from the fuel cell is transferred to the fuel supply pipe 3.
1 and the combustion air enters the catalytic combustor 26 through the combustion air supply pipe 32, these mixtures pass through a number of holes n of the catalytic combustor 26.

The catalyst supported on the inner wall surface of the opening n oxidizes, that is, burns, and generates heat on the inner wall surface. This heat is conducted through the molded body of the catalytic combustor and transferred to the vaporizer 29 embedded in the molded body. As a result, the reforming raw material liquid fuel supplied to the vaporizer 629 and flowing backward is vaporized and becomes raw material gas. The combustion gas passes through the numerous holes υ of the catalytic combustor, passes through the combustion chamber, the gas exhaust pipe, and heats the aforementioned reformer. Therefore, the raw material gas produced in the vaporizer is reformed into a hydrogen-rich gas in the reformer, and the reformed gas is supplied to the fuel cell.

By the way, the vaporized W 29 buried in the catalytic combustor 26 @
As mentioned above, the heating method is to use the heat generated by combustion in the catalytic combustor section through conductive heat transfer through the molded body.
The liquid fuel flowing through it is not locally heated,
Since the liquid fuel is heated quickly, stable vaporization of the liquid fuel is performed, and pressure fluctuations in the reformed gas supplied to the fuel cell can be reduced. Further, by providing a large number of hole moss in the molded body of the catalytic combustor 26, combustion gas flows through a large number of holes n, so that pressure loss is small.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, by embedding the vaporizer of the fuel reformer in the catalytic combustor, the heat of the combustion gas in the catalytic combustor is vaporized by conductive heat transfer within the catalytic combustor. Since the liquid fuel flowing through the device is heated quickly without being locally heated, vaporization is performed stably and pressure fluctuations in the reformed gas supplied to the fuel cell are reduced.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a combustor and a carburetor of a fuel reformer according to an embodiment of the present invention, and FIG. 2 is a system diagram of a fuel cell power generation system comprising a fuel reformer and a fuel cell.

Claims (1)

[Claims] In a fuel reformer that vaporizes reformed liquid fuel using a heat transfer medium from a combustor to reform it into hydrogen-rich gas, a catalyst that has holes for a combustion gas flow path along the inner wall of a case-shaped furnace body. A combustor is provided, a vaporizer communicating with the outside is buried in the catalytic combustor, a fuel supply pipe and a combustion air supply pipe are opened in an inlet region of the catalytic combustor, and a combustion gas exhaust pipe is opened in an outlet region of the catalytic combustor. A fuel reformer characterized by: