JP2003277012A - Apparatus and method for supplying raw material to hydrogen producer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for supplying raw materials, in which the flow rate of raw water to be supplied to a fuel cell power generation apparatus can be precisely controlled by a simple structure. <P>SOLUTION: A raw material hydrocarbon is pressurized and then fed to a water storage vessel 11 where the raw water is stored so that the hydrocarbon and the raw water are kept in the pressurized states under the same pressure. After that, the pressurized hydrocarbon and the raw water are supplied from the vessel 11 to a hydrogen producer 1 through different throttling apparatuses 14, 18, respectively. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raw material supply device and a method for supplying a raw material to a hydrogen generator for producing a hydrogen compound from a hydrocarbon compound and water as a raw material and supplying it to a fuel cell.

[0002]

2. Description of the Related Art A hydrogen generator for supplying hydrogen fuel to a fuel cell power generator includes a reformer for reacting a hydrocarbon as a raw material with water to generate hydrogen by a steam reforming reaction, Formed by a shift reactor for removing carbon monoxide water by a shift reaction and a selective oxidizer for removing a slight amount of residual carbon monoxide by selective oxidation using oxygen in the air.

Among them, as a method of supplying water as a raw material to the reformer, in a large-scale commercial phosphoric acid fuel cell power generator having a relatively high temperature and a power generation output of several tens of kW or more, the water raw material is supplied at high temperature and high pressure. A method of supplying by evaporating into water vapor (for example,
JP-A-10-223244 and JP-A-2000-27
No. 7134 gazette is adopted, but the power generation output is 1
In a general household organic solid oxide fuel cell power generator having a small size of about kW, a method of supplying a water raw material with a pump to evaporate it (for example, Japanese Patent Laid-Open No. 11-106204 and Japanese Patent Laid-Open No. 20204/1999).
No. 01-10804) are used. In the former case, the amount of water to be supplied is controlled mainly by adjusting the pressure of water vapor and the rotation speed of the water supply pump, and in the latter case, the rotation speed of the water supply pump is mainly adjusted.

[0004]

The supply amount of the water raw material is approximately proportional to the electric output of the fuel cell power generator. For example, for commercial use with a large power generation output, the supply amount of water raw material is several tens cc /
Although it is about several cc / min to several hundred cc / min, the supply amount of the water raw material is very small, about several cc / min, for household use with a small power generation output of about 1 kW.

On the other hand, in the steam reforming reaction, it is necessary to control the ratio of the feed rates of the hydrocarbon raw material and the water raw material to be constant. When the feed amount of the water raw material is smaller than that of the hydrocarbon raw material, the generation amount of carbon monoxide increases, and further, the carbon adheres to the catalyst surface in the reformer and the catalytic performance deteriorates. On the contrary, if the supply amount of the water raw material is large, an excessive amount of heat is consumed due to its evaporation, and the power generation efficiency is reduced.

However, it has been difficult to accurately control the supply amount of a small amount of water raw material such as several cc / minute by using a pump. Therefore, it was necessary to supply a large amount of water raw material because of the need to suppress the increase of carbon monoxide and the precipitation of carbon, and the reduction of power generation efficiency was unavoidable.

Further, since it is necessary to control the supply amounts of both the hydrocarbon raw material and the water raw material, both flow rate control devices are required, and the cost of the fuel cell power generation device is high.

Further, the operation of the reformer becomes unsteady at the time of start-up or during the operation in which the power generation output is adjusted according to the power load, and the temperature and pressure inside the reformer fluctuate. At that time, since the discharge pressure of the water raw material supply pump and the hydrocarbon raw material supply compressor fluctuates, it becomes impossible to supply a predetermined amount, and one of the raw materials temporarily becomes in excess or shortage. There was a problem that it would end up. Particularly, even temporarily, the shortage of the water raw material increases the amount of carbon monoxide generated and deteriorates the catalyst performance, which is not preferable.

In view of such problems of the conventional raw material supply device for the hydrogen purifier, the present invention is a raw material capable of accurately controlling the flow rate of the water raw material supplied to the fuel cell power generator with a simple structure. It is an object to provide a supply device and method.

[0010]

The first aspect of the present invention is a raw material supply device for a hydrogen generator that produces hydrogen from an organic compound and water as raw materials, wherein the organic compound raw material and the water raw material are pressurized to the same pressure. After that, it is a raw material supply device for the hydrogen generator, which supplies the hydrogen to the hydrogen generator through different expansion devices.

In a second aspect of the present invention, a pressurizer for pressurizing the organic compound raw material, and storing the water raw material, the pressurized organic compound raw material flows in and out.
A water raw material storage container, the discharged organic compound raw material, an organic compound supply pipe for supplying the hydrogen generator via the first expansion device, and the water raw material from the water raw material storage container,
A raw material supply device for a hydrogen generator according to the first aspect of the present invention, comprising a water supply pipe for supplying the hydrogen generator via a second expansion device.

A third aspect of the present invention is a raw material supply apparatus for a hydrogen generator according to the first aspect of the present invention, further including a heat exchanger for heating a water raw material, which is provided in the middle of the water supply pipeline. is there.

In a fourth aspect of the present invention, the water level of the water raw material in the water raw material storage container is equal to or higher than the water raw material supply position of the hydrogen generator. 1 is a raw material supply device for a hydrogen generator according to the first aspect of the present invention.

A fifth aspect of the present invention provides the first diaphragm device and / or
Or, the flow resistance of the second expansion device is variable stepwise,
It is a raw material supply device for the hydrogen generator of the first aspect of the present invention.

A sixth aspect of the present invention is to arrange a water raw material supply container at a position lower than the water raw material storage container, to supply the water raw material in the water raw material supply container to the water raw material storage container, It is a raw material supply device for a hydrogen generator according to the first aspect of the present invention, which has a conduit for returning a water raw material overflowing from a raw material storage container to the water raw material supply container.

A seventh aspect of the present invention is a method for supplying a raw material to a hydrogen generator for producing hydrogen from an organic compound and water as raw materials, wherein the organic compound raw material and the water raw material are pressurized to the same pressure, and then different throttles are respectively provided. It is a method for supplying a raw material to a hydrogen generator, which is supplied to the hydrogen generator through an apparatus.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the following description of the present invention,
A hydrocarbon will be described as an example of the organic compound. However, the organic compound of the present invention includes gasoline and the like in addition to such hydrocarbons.

The raw material supply device of the present invention supplies a hydrocarbon raw material and a water raw material to the hydrogen generator through different expansion devices, and restricts the upstream and downstream pressures of the expansion devices to the same pressure. The feed ratio of the two raw materials flowing through is constant.

As a concrete constitution, first, the hydrocarbon raw material is pressurized, and the pressurized hydrocarbon raw material is supplied to a water raw material storage container for storing the water raw material to pressurize the water raw material to The pressure is the same. Since the hydrocarbon raw material and the water raw material are mixed before reacting in the hydrogen generator downstream of the throttle, it is not necessary to connect the hydrocarbon raw material pipe and the water raw material pipe to one pipe downstream of the throttle.

Further, by disposing a heat exchanger for heating the water raw material in the middle of the pipeline connecting the hydrogen generator with the downstream of the throttle of the water supply pipeline, the heat exhausted in the fuel cell power generator is provided. It can be recovered and the thermal efficiency of the power generator can be improved.

The positional relationship between the water raw material storage container and the hydrogen generator is related to stable operation of the raw material supply device of the present invention. Depending on the accuracy of the pressure after pressurizing the hydrocarbon raw material, the water raw material is stably supplied by setting the water level of the water raw material in the water raw material storage container to a position higher than the water raw material supply position of the hydrogen generator. can do.

When the fuel cell power generator is started or stopped, or when the load is changed, it is necessary to supply the hydrocarbon raw material and the water raw material at a different ratio from the steady state. At that time, in the present invention, the flow resistance of the expansion device is made variable stepwise so that the raw material can be supplied at a predetermined flow rate ratio.

In the present invention, the pressure of the hydrocarbon raw material is applied to the water raw material storage container so that the pressure of both raw materials upstream of the expansion device is the same. However, in order to control the flow rate of the water raw material more accurately, It is necessary to maintain a constant height from the expansion device to the water surface in the water raw material storage container. Therefore, in the present invention, the water raw material supply container is arranged at a position lower than the water raw material storage container, and the water surface position is made constant by overflowing the water raw material of a predetermined height in the water raw material storage container.

Specific embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic view of a fuel cell power generator using city gas as a hydrocarbon raw material according to a first embodiment of the present invention.

In FIG. 1, 1 is a hydrogen generator comprising a reformer 2, a shift reactor 3 and a selective oxidizer 4, 5 is a fuel cell, and 6 is a shift for supplying water as a raw material to the shift reactor 3. A reaction water supply line, 7 is an air supply line for supplying air to the selective oxidizer 4. In the present embodiment, the present invention is used in the supply unit of city gas and water which are the raw materials to be supplied to the reformer 2.

In the figure, reference numeral 8 is a city gas supply pipe. City gas is pressurized to 10 kPa by a blower 9, regulated by a pressure regulator 10, passed through a water raw material storage container 11, and then a city gas supply pipe 12 Through the city gas flow meter 13,
It is supplied to the reformer 2 through the first expansion device 14 and the first opening / closing valve 15.

On the other hand, the water raw material 16 used for the steam reforming reaction is pressurized by the city gas in the water raw material storage container 11, and then the second expansion device 18, through the reforming water supply pipe 17.
It is supplied to the reformer 2 through the second opening / closing valve 19.

The water raw material supplied to the water raw material storage container 11 is pumped up and supplied from the water raw material supply container 20 using the pump 21. Further, an overflow pipe 22 is provided in the water raw material storage container 11 so that the water surface in the water raw material storage container 11 is always constant. As a result, the water pressure at the inlet of the second expansion device 18 becomes the sum of the pressure of the pressurized city gas and the water column pressure from the water surface to the second expansion device 18, and is always constant. Water column pressure is water raw material storage container 11
Although it depends on the positional relationship between the reformer 2 and the reformer 2, the water level in the water raw material storage container 11 and the height of the supply part to the reformer 2 can be made substantially equal to each other (FIG. 5). reference). In addition, reference numeral 23 in the figure denotes a water supply pipeline for supplying water to the water raw material supply container 20.

On the other hand, inside the reformer 2, the city gas and the water raw material are mixed (not shown), but the pressures of the city gas and the water raw material in the mixing section are naturally equal.

As described above, according to the present invention, since the upstream and downstream pressures of the first expansion device 14 and the second expansion device 18 for city gas and water raw material are made equal to each other, the city gas under pressure is pressurized. Even if the pressure of the fuel gas and the pressure of the mixing portion of the two raw materials in the reformer fluctuate, the raw materials of the city gas and the water raw material always flow at a constant ratio. This principle will be described with reference to FIG.

FIG. 2 is a flow rate curve showing the pressure difference before and after the expansion device and the flow rate flowing through each expansion device. The flow rate through the throttling device increases approximately linearly with the pressure difference across the throttling device. Assuming that the pressure difference across the throttle devices when the fuel cell power generator is operating in a steady state is ΔP1, city gas is supplied at a flow rate of Q1, and water raw material is supplied at a flow rate of q1. However, the blower that pressurizes the city gas for some reason 9
When the discharge pressure increases, or the pressure inside the reformer 2 decreases due to the load fluctuation of the fuel cell power generator, the pressure difference before and after the expansion device increases to ΔP2. Increase to Q2 and q2. However, since the flow rate curve is substantially linear, the flow rate ratio Q2 / q2 is kept substantially equal to Q1 / q1. That is, in the present invention, since the pressures of the city gas and the water raw material before and after both expansion devices are equalized, both raw materials can be always supplied at a constant ratio.

Further, in the present invention, a pump for supplying water raw material and a flow meter are unnecessary. Further, since the flow rate control can be performed only by controlling the city gas flow rate by the blower 9 or the pressure control by the pressure regulator 10, the raw material supply section can be greatly simplified and the cost can be greatly reduced. Since the drive part such as a pump causes a failure, the reduction of the pump and the flow meter according to the present invention also brings important effects of improving the life and reliability of the fuel cell power generator.

The first on-off valve 15 and the second on-off valve 19 shown in FIG. 1 open and close the pipeline when the operation is stopped or started, and are not essential requirements of the present invention.

Further, in the present embodiment, the pressure regulator 10 is used as the means for regulating the pressure of the city gas under pressure, but the present invention is not limited to this pressure regulating means.

Further, although the case where city gas is used as the hydrocarbon raw material has been described in the present embodiment, the hydrocarbon raw material is not limited to city gas, and other raw materials such as LPG may be used. Moreover, even if it is a liquid fuel such as kerosene or gasoline, the technique of the present invention can be used as long as it is insoluble in the water raw material.

(Embodiment 2) FIG. 3 shows a second embodiment of the present invention.

In FIG. 3, the same components as those in FIG. 1 are designated by the same reference numerals. This embodiment is different from the above-mentioned embodiments in that the heat exchanger 2 is provided in the middle of the reforming water supply pipe 17.
4 is arranged to heat the water raw material supplied to the reformer 2. As the heat source 25 of the heat exchanger 24, the heat discarded from the fuel cell 5 and the reformer 2 can be used. By effectively utilizing the heat in the fuel cell power generator in this way, the thermal efficiency of the power generator can be improved. It is desirable that the water raw material supplied to the reformer 2 be completely evaporated by the heat exchanger 24, but if the water raw material can be heated in a partially evaporated state or even without evaporation at all, the thermal efficiency is improved. It can contribute to improvement.

Although the heat exchanger 24 is different from the reformer 2 in the present embodiment, in order to use the heat of the reformer 2 more effectively, the heat exchanger 24 is replaced with the reformer 2. It is desirable to have a configuration that is built in.

When the water raw material is partly evaporated in the heat exchanger 24, a mixed phase fluid of steam and hot water is supplied to the reformer 2, and pressure fluctuations may occur depending on the degree of evaporation and the flow state. Occurs. However, as described above, the raw material supply device of the present invention has an excellent characteristic that the supply ratio of the city gas and the water raw material is always kept constant even if pressure fluctuations occur. Does not occur.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention.

In FIG. 4, the same components as those described above are designated by the same reference numerals. This embodiment is different from the above-described embodiments in that the water raw material in the water raw material storage container 11 is transferred to the shift reactor 3 via the shift water supply pipe 26, the third expansion device 27 and the third opening / closing valve 28. It is also a point to supply. Although carbon monoxide is removed by reacting it with water in the shift reactor 3 as described above, the present embodiment uses the present invention to supply the water raw material.

The flow rate of the water raw material used for the shift reaction is smaller than the flow rate of the water raw material used for the steam reforming reaction. For example, in a household combustion battery power generator having a power generation output of about 1 kW, the flow rate of the water raw material used for the shift reaction is a minute amount of about several cc / min, and it is difficult to accurately control this slight flow rate. . In the present invention, by increasing the flow resistance of the third expansion device 27, it is possible to easily and accurately supply a minute flow rate. Moreover, by using the present invention, a feed pump and a flow rate control of the water raw material for the shift reaction are not required, so that the device can be simplified and the cost of the fuel cell power generator can be reduced.

(Embodiment 4) FIG. 5 shows a fourth embodiment of the present invention.

FIG. 5 shows the positional relationship in the height direction between the raw material supply device of the present invention and the hydrogen generator for supplying the raw material. In this embodiment, the same components as those described above are designated by the same reference numerals. In the present embodiment, the liquid surface of the water raw material 16 in the water raw material storage container 11 (A in the drawing) is arranged to be higher than the water raw material supply position (B in the drawing) of the reformer 2. . By arranging in this way,
The water raw material can be stably supplied.

FIG. 6 shows the case of arranging in a position opposite to that of the present invention.
Shown in. FIG. 6 shows a case where the liquid surface of the water raw material 16 (A ′ in the drawing) is arranged lower than the water raw material supply position (B ′ in the drawing) of the reformer 2 by a height H. In this case, the water raw material in the reforming water supply pipe 17 tries to return to the water raw material storage container 11 by its own weight.
The height of H of the water raw material in the reforming water supply pipe 17 is raised by the pressure of the city gas pressurized in the water raw material storage container 11, but the pressure fluctuation and reforming in the water raw material storage container 11 are caused. The water raw material in the reforming water supply pipe 17 may vibrate up and down due to the pressure fluctuation in the vessel 2. At that time, although the supply of the water raw material is interrupted for a short time, problems such as an increase in the concentration of carbon monoxide and carbon deposition occur and it becomes impossible to stably operate the fuel cell power generator.

Therefore, in this embodiment shown in FIG.
By setting the liquid surface of the water source to a position higher than the water raw material supply position of the reformer 2, the direction in which the water raw material flows by its own weight and the direction in which the pressure in the water raw material storage container 11 flows are made to coincide with each other, and The generation of vertical vibration of the water raw material in 17 is suppressed.

Of course, if the liquid surface of the water raw material 16 in the water raw material storage container 11 is even lower than the water raw material supply position of the reformer 2, the vibration of the water raw material in the reformed water supply pipe 17 will always occur. Therefore, in the present invention, the positions of the both may be substantially the same.

(Embodiment 5) The amount of household electric power used varies greatly depending on the time of day and night and the season. Therefore, the fuel cell power generator is indispensable for the function of adjusting the generated electric power to be supplied according to the electric power load. In order to adjust the amount of electric power generated by the fuel cell power generator, it is necessary to adjust the flow rates of the hydrocarbon raw material and the water raw material supplied to the hydrogen generator. The present invention shows a specific configuration of the expansion device for adjusting the flow rate of the raw material in the above-described embodiment.

An embodiment of the present invention is shown in FIG. FIG. 7 is a schematic configuration diagram of the expansion device of the present invention, which corresponds to the first expansion device 14, the second expansion device 18, and the third expansion device 27 of the above-described embodiment, and 29 is the city gas supply. Tube 1
2. Pipe lines corresponding to the reforming water supply pipe 17 and the shift water supply pipe 26.

In FIG. 7, reference numerals 30 to 32 are flow resistance members configured so that the flow resistance is gradually reduced. Specifically, the flow resistance is adjusted by using a thin tube and sequentially shortening its length. . Also, 33 to 35 are open / close valves,
36 is a branch pipe and 37 is a confluent pipe.

The operation of the diaphragm device configured as described above will be described below.

The raw material flowing from the upper side to the lower side in the pipe line 29 is branched into the flow resistance bodies 30 to 32 by the branch pipe 36, merges again in the merge pipe 37, and then flows out downward. At this time, by closing any one or two of the opening / closing valves 33 to 35, or by opening all the opening / closing valves 33 to 35, the flow resistance of the expansion device can be adjusted to 7 types. .

That is, when the flow resistance is minimized, all the on-off valves 33 to 35 are opened, and when the flow resistance is maximized, the on-off valve 33 is opened and the open-close valves 34 and 35 are closed. .

Further, the flow resistance between them can be set by a combination of opening and closing of the on-off valves 33 to 35. On the other hand, the flow rate changes due to the flow resistance. Therefore, as in the present embodiment, the flow rate can be adjusted in seven stages by using three types of flow resistance elements in combination, and the amount of power generated by the fuel cell power generator can be adjusted in seven stages with a simple configuration. It will be possible.

The configuration shown in FIG. 7 is an example of the present invention, and the type and number of flow resistance elements may be appropriately optimized as needed.

Further, the present invention is not limited to the case of being used for the hydrogen generator of the fuel cell, but can be used for the hydrogen purifier of other fields.

[0058]

As described above, according to the present invention, the flow rate of the water raw material can be accurately controlled with a simple structure. Therefore, when used in a fuel cell, power generation can be performed with high efficiency and stability.

Further, according to the present invention, a flow rate control device for raw material water is not required, so that when used in a fuel cell, the cost of the fuel cell power generation device can be reduced.

Further, when used in a fuel cell, the present invention makes it possible to easily adjust the amount of power generated by the fuel cell power generator.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a raw material supply device according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the raw material supply device of the present invention.

FIG. 3 is a schematic configuration diagram of a raw material supply device according to a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a raw material supply device according to a third embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a raw material supply device according to a fourth embodiment of the present invention.

FIG. 6 is an explanatory diagram related to a form of a fourth embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a raw material supply device according to a fifth embodiment of the present invention.

[Explanation of symbols]

1 ... Hydrogen generator 2 reformer 3 ... Shift reactor 4 ... Selective oxidizer 5 ... Fuel cell 6 ... Shift reaction water supply line 7 ... Air supply line 8: City gas supply piping 9 ... Blower 10 ... Pressure regulator 11 ... Water raw material storage container 12 ... City gas supply pipe 13 ... City gas flow meter 14 ... First throttling device 15 ... First opening / closing valve 16 ... Water raw material 17 ... Reforming water supply pipe 18 ... Second diaphragm device 19 ... Second on-off valve 20 ... Water raw material supply container 21 ... Pump 22 ... Overflow piping

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akira Maenishi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Tomonori Aso             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Kao Tamura             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 4G068 AA01 AB01 AB11 AC01 AD40                       AF01                 4G140 EA03 EA06 EB03 EB04                 5H027 AA02 BA01

Claims (7)

[Claims] 1. In a raw material supply device for a hydrogen generator that produces hydrogen from an organic compound and water as raw materials, after pressurizing the organic compound raw material and the water raw material to the same pressure,
A raw material supply device for supplying hydrogen to the hydrogen generator through different throttle devices. 2. A pressurizer for pressurizing the organic compound raw material, a water raw material storage container for storing the water raw material, and at which the pressurized organic compound raw material flows in and out, and the outflowing organic material. An organic compound supply pipe for supplying a compound raw material to the hydrogen generator via a first expansion device, and an organic compound supply pipe for supplying the water raw material from the water raw material storage container to the hydrogen generator via a second expansion device. And a water supply pipe for supplying the raw material to the hydrogen generator according to claim 1. 3. The raw material supply device for a hydrogen generator according to claim 1, further comprising a heat exchanger for heating the water raw material, which is provided in the middle of the water supply pipeline. 4. The water level of the water raw material in the water raw material storage container is equal to or higher than the water raw material supply position of the hydrogen generator.
The raw material supply device for the hydrogen generator according to claim 1. 5. The raw material supply device for a hydrogen generator according to claim 1, wherein the flow resistance of the first expansion device and / or the second expansion device is variable stepwise. 6. The water raw material supply container is arranged at a position lower than the water raw material storage container, means for supplying the water raw material in the water raw material supply container to the water raw material storage container, and the water raw material storage container. The raw material supply device for a hydrogen generator according to claim 1, further comprising a conduit for returning the water raw material overflowed from the water raw material supply container to the water raw material supply container. 7. A method of supplying a raw material to a hydrogen generator for producing hydrogen from an organic compound and water as raw materials, comprising: pressurizing the organic compound raw material and the water raw material to the same pressure;
A method for supplying a raw material to a hydrogen generator, wherein the raw material is supplied to the hydrogen generator via different expansion devices.