Chemistry: electrical current producing apparatus – product – and – Having magnetic field feature
Reexamination Certificate
2000-05-15
2004-09-28
Kalafut, Stephen (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Having magnetic field feature
C429S010000, C429S006000
Reexamination Certificate
active
06797418
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a fuel processor for a fuel cell, and more particularly to a fuel processor for a fuel cell capable of shortening a warm up time.
DESCRIPTION OF THE RELATED ART
A polymer electrolyte type of fuel cell includes a stack cell with a polymer electrolyte film sandwiched between an anode and cathode, and generates power through an electrochemical reaction by supplying hydrogen to the anode and oxygen to the cathode.
Since hydrogen ions generated in the anode permeate through the polymer electrolyte film to move to the cathode, in order to hold the ion conductivity of the polymer electrolyte film, it is necessary to supply water to the polymer electrolyte film.
Conventionally, a fuel processor has been used as a source for supplying hydrogen to the fuel cell. The fuel processor vaporizes a raw fuel such as hydrocarbon compound or alcoholic compound and water to create a water/fuel mixed gas and reforms it by using a reforming catalyst, thereby creating a reformed gas containing hydrogen (fuel).
The fuel processor causes the reformed gas to contain excessive water vapor in order to supply water to the polymer electrolyte film of the fuel cell.
Now referring to the drawings, an explanation will be given of the conventional fuel processor for a fuel cell. FIG.
3
shows an entire arrangement of a conventional fuel processor
101
.
The fuel processor
101
mainly includes a combustion section
102
for generating a fuel gas, a vaporizing section
103
for vaporizing a mixed solution of raw fuel and water by heat of the combustion gas to create a water/fuel mixed gas, a reforming section
104
for reforming the water/fuel mixed gas by a reforming catalyst to create a reformed gas containing hydrogen, a carbon-monoxide removal section
105
(hereinafter referred to as CO removal section) for oxidizing/removing carbon monoxide by-produced in the reformed gas by a selective oxidizing catalyst and a starting combustion section
106
.
The combustion section
102
includes a catalyst for combustion and is provided with a fuel tank
107
for combustion. The vaporizing section
103
is provided with an injecting device
109
equipped with a mixed solution tank
108
via a conduit
110
. The mixed solution tank
108
is filled with a mixed solution of raw fuel and water. The raw fuel is usually an alcoholic component such as methanol and a hydrocarbon compound such as methane, ethane and gasoline.
The starting combustion section
106
includes a catalyst for combustion and is provided with a supplying device (not shown) for supplying fuel for starting combustion and air.
The CO removal section
105
is connected to a polymer electrolyte type fuel cell
51
via a conduit
111
.
An explanation will be given of the operation until the fuel processor
101
is started to reach a stationary running state.
First, starting fuel is burned in the starting combustion section
106
, and the starting combustion gas thus generated is supplied to the reforming section
104
through the conduit
112
to warm the reforming section
104
and CO removal section
105
.
At the same time, combustion fuel is burned in the combustion section
102
, and the combustion gas thus generated is supplied to the vaporizing section
103
through the conduit
113
to warm the vaporizing section
103
.
When the reforming catalyst in the reforming section
104
reaches about 200° C. and the vaporizing section
103
reaches the temperature (about 200° C.) capable of vaporizing a water/fuel mixed gas, supply of the starting fuel to the starting combustion section
106
is stopped. Simultaneously, the mixed solution is supplied to the injecting device
109
from the mixed solution tank
108
so that the mixed solution is injected into the vaporizing section
103
. Then, the mixed solution is vaporized by the heat of the combustion gas supplied from the combustion section
102
thereby to create a water/fuel mixed gas.
The water/fuel mixed gas is supplied to the reforming section
104
via the conduit
114
. Simultaneously, the reforming section
104
is supplied with air from the starting combustion section
106
. As a result, the raw fuel is reformed into a reformed gas containing hydrogen under the presence of water vapor and oxygen by the reforming catalyst included in the reforming section
104
.
The reformed gas is sent to the CO removal section
105
via the conduit
113
so that carbon monoxide by-produced in the reformed gas is oxidized and removed using the selective oxidizing catalyst. The reformed gas thus produced is supplied to the fuel cell
51
via the conduit
111
.
In the fuel processor
101
described above, the mol ratio (hereinafter referred to S/C ratio) of steam to carbon(s) (the number of carbon contained in the fuel) in the water/fuel mixed gas is set within a range of 1.5-2.5 so that the mol amount of water vapor in the water/fuel mixed gas is made more than the theoretical reaction mol amount of water in a reforming reaction (in terms of the mol ratio, raw fuel (methanol):water =1:1), thereby leaving the excessive water vapor after the reforming reaction in the reforming gas. Further, by supplying the reformed gas containing the excessive water vapor to the fuel cell
51
, water can be supplied to the polymer electrolyte film of the fuel cell
51
.
However, the conventional reforming apparatus
101
for a fuel cell has the following problems. In order to increase the S/C ratio of the water/fuel mixed gas is increased, the amount of water to be injected into the vaporizing section
103
is increased. In this case, since the vaporizing heat of water is higher than that of the raw fuel of methanol, a large amount of heat is required to create the water/fuel mixed gas and hence the amount of heat for warming the vaporizing section is reduced. Therefore, it takes a long time to warm the fuel processor
101
.
Further, in the conventional reforming apparatus
101
, the reforming section
104
and CO removal section
105
are warmed by the starting combustion section
106
. In this case, since the CO removal section
105
is provided downstream of the reforming section
104
, even when the reforming section
104
is warmed so that the fuel processor
101
reaches its running state, the CO removal section
105
and the conduit
111
downstream thereof are not still warmed (as the case many, the temperature thereof is 80° C. or lower).
In this state, when the reformed gas containing water vapor passes the CO removal section
105
and conduit
111
, water vapor is condensed into water in the CO removal section
105
and conduit
111
. The remaining water reduces the catalytic capability of the selective oxidizing catalyst to lower the removal efficiency of carbon monoxide and closing the flow path of the reforming gas.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a fuel processor for a fuel cell which has a short machine-warming running time and does not provide condensation of water vapor in a reformed gas within the apparatus in a machine-warming running state.
In order to attain the above object, the present invention adopts the following constitution.
The fuel processor for a fuel cell according to the invention includes a vaporizing section for vaporizing water and raw fuel containing hydrocarbon to create a water/fuel mixed gas (vaporizing section
3
in an embodiment); and a reforming section for reforming the water/fuel mixed gas to create a reformed gas containing hydrogen (reforming section
4
in the embodiment).
The fuel processor for a fuel cell further includes adjustable supplying means (first and second injecting devices
12
and
13
in the embodiment) for supplying the raw fuel and the water to the vaporizing section and adjusting a mol ratio of steam to carbon(s) (the number of carbon(s) in the fuel) (hereinafter referred to as “S/C ratio”) in the water/fuel mixed gas; temperature detecting means (third thermometer
24
in the embodiment) installed on a deriving flow path (deriving conduit
41
in the embodi
Kawasaki Nobuyuki
Kotani Yasunori
Nomura Tadashi
Otaka Akifumi
Arent Fox Kintner & Plotkin & Kahn, PLLC
Honda Giken Kogyo Kabushiki Kaisha
Kalafut Stephen
Mercado Julian
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