JPH07106881B2 - Fuel cell reformer device - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a reformer device used in a fuel cell for promoting a reforming reaction of a hydrocarbon-based gas.

[Technical background of the invention] In recent years, fuel cells, which have been expected and interested in research on their development and practical application, release the chemical energy of the fuel by an electrochemical process by oxidizing the chemical energy of the fuel. It is a device that directly converts the energy to be converted into electric energy. In a power plant using this fuel cell, the thermal efficiency of power generation reaches 40 to 50% even on a relatively small scale,
It is expected to far surpass new thermal power generation. In addition, SO is a pollution factor that has become a major social problem in recent years.
Extremely low x and NOx emissions. Since the power generator does not include a combustion cycle, a large amount of cooling water is not required, and vibration noise is small. In principle, high energy conversion efficiency can be expected, and there are few environmental problems such as noise and exhaust gas.
Furthermore, there are features such as good responsiveness to load fluctuations.

In such a fuel cell, a reformer device is arranged in order to add steam to a hydrocarbon-based fuel such as natural gas to heat-transform it to obtain a hydrogen-rich reaction gas.

The structure of such a reformer device will be described with reference to the sectional views shown in FIGS. 3 and 4. That is, in the upper part of the reformer 1,
Fuel sent from a conduit 2 connected to a fuel tank (not shown), and a conduit 3 connected to an air supplier (not shown)
Main burner 4 that mixes and burns the air sent in
Is provided. In order to ignite this main burner 4,
A conduit 5 for supplying fuel, a conduit 6 for supplying air, and an auxiliary burner 7 having an electric igniter at its tip are provided on the sides of the main burner 4. Further, the combustion exhaust gas of the main burner 4 flows downward in the combustion chamber 8, passes through the outer peripheral space of the reforming pipe 9 arranged inside the reformer 1, and is disposed in the lower layer of the outer peripheral space. After passing through the conduit 10 holding the sphere 11, the exhaust gas pipe 12 passing through the conduit 10 is discharged to the outside of the reformer 1, and is guided to a turbo compressor (not shown) to contribute to the operation. Further, a mixed gas of a hydrocarbon-based fuel such as natural gas and steam is introduced into a reforming pipe 9 arranged inside the reformer 1 from a conduit 13 connected to a lower portion thereof,
The mixed gas passes through the pipe line in the reforming tube 9 holding the catalyst particles 14. At this time, the reforming reaction of the mixed gas is carried out by the heat obtained by the combustion of the main burner 4 and the action of the catalyst particles 14 to become a hydrogen-rich gas. The reformed gas thus obtained flows downward through the conduit 15 in the reforming pipe 9, and is guided to the outside of the reformer 1 through the conduit 16 communicating with this.

Next, the arrangement of various devices connected to the reformer 1 will be described with reference to the system diagram of FIG. That is, a gas mixed by a conduit 17 for supplying a hydrocarbon fuel such as natural gas and a conduit 18 for introducing steam is sent to a heat exchanger 19, and a pipe through which a high temperature gas is passed through the heat exchanger 19.
After being heated by 20 to raise the temperature, it is sent into the reformer 1 through the conduit 13. Further, the reformed gas that has become a hydrogen-rich gas in the reformer 1 is guided to the outside of the reformer by the conduit 16, is sent to the heat exchanger 21, and the cooling gas is passed through the heat exchanger 21. After the temperature is lowered by the pipe 22, carbon monoxide CO contained in the reformed gas is converted into carbon dioxide CO
_It is sent to the fuel cell through a high-temperature transformer 23 and a low-temperature transformer (not shown) that change to ₂ , and contributes to power generation.

[Problems of Background Art] In the reformer 1 as shown in FIGS. 3 to 5, the temperature of the mixed gas of fuel and steam in the conduit 13 at the inlet of the reforming pipe 9 is It is necessary to control the temperature within the range of 427 ℃ to 510 ℃. The reason is that when the temperature is 427 ° C. or lower, polypropylene is deposited on the catalyst 14 in the reforming tube 9 and the performance of the catalyst 14 is deteriorated. Also, 510 ℃
In the above case, the fuel is decomposed to generate carbon, and the carbon enters the structure of the catalyst 14 to destroy the catalyst 14 and pulverize it to increase the differential pressure in the reforming tube 9, which is a drawback. It was

Further, the mixed gas of fuel and steam introduced from the lower part into the reforming pipe 9 arranged in the reformer 1 is heated as the temperature rises in the catalyst layer 14 in the reforming pipe 9 and the temperature is raised. Rises to 760
The main burner 4 of the reformer 1 heats and controls the reforming tube 9 so that a reaction of reforming into hydrogen gas occurs at a temperature of not less than 0 ° C. and the maximum temperature at the upper portion of the reforming tube 9 becomes 982 ° C. Further, the hydrogen-rich gas reformed in this way is transmitted to the catalyst 14 when flowing downward from the top of the reforming pipe 9 through the pipe 15, and about 593 at the outlet of the reforming pipe 9. It is necessary to control at ℃.
Further, in the gas reacted in the reforming tube 9, carbon monoxide CO
Is contained in the reformed gas temperature, which is about 593 ° C. at the outlet of the reforming tube 9, in order to convert it into harmless carbon dioxide CO ₂ because it harms the battery body. Exchanger 21
The temperature is lowered to 387 ° C. or higher and 421 ° C. or lower by the cooling gas or the cooling water in the conduit 22 provided inside and sent to the high temperature shift converter 23 to cause a catalytic reaction to convert carbon monoxide CO into carbon dioxide CO ₂ .

Next, the basic reforming reaction formula of the above-mentioned fuel and steam will be shown.

“Reaction in reforming pipe” CH ₄ + 2H ₂ O + heat → CO + H ₂ O + 3H ₂ “Reaction of high temperature converter” CO + H ₂ O → heat + CO ₂ + H _{2 As} described above, the fuel fed into the reforming pipe 9 The temperature of the mixed gas of steam must be raised from about 200 ° C to 427 ° C to 510 ° C, and the temperature of the reformed gas that has passed through the reforming tube 9 is also about 593 ° C. Suitable for 23 3
Must be lowered to 87 ° C-421 ° C.

However, when the temperature of the mixed gas of natural gas and steam is raised by the heat exchanger 19, the heat exchanger 21
Even when the temperature of the reformed gas is lowered by the above method, there is a drawback that the temperature control cannot be accurately performed because the temperature difference of the heat exchange is very large.

[Object of the Invention] The present invention has been proposed in order to solve the above-mentioned drawbacks of the prior art, and its object is to reform a mixed gas of natural gas and steam into a hydrogen-rich gas. It is an object of the present invention to provide a reformer device used in a fuel cell reformer device, which enables accurate and easy temperature control and energy saving.

[Summary of the Invention] The reformer apparatus of the present invention is provided with a heat exchanger capable of exchanging heat between the natural gas introduction conduit and the reformed gas discharge conduit, and A bypass pipe is provided in the reformed gas discharge conduit, an automatic control valve is provided in the bypass pipe and the reformed gas discharge conduit, and a temperature detector is installed in the natural gas introduction conduit. By installing a controller and connecting it to the automatic control valve, efficient heat exchange is performed between the natural gas introduction conduit and the reformed gas discharge conduit, and the temperature is controlled by the temperature detector. It is designed to be able to perform accurately.

[Embodiment of the Invention] An embodiment of the present invention will be specifically described below with reference to FIGS. 1 and 2. The same members as those of the conventional type shown in FIGS. 3 to 5 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, a first conduit 13 for introducing a mixed gas of natural gas and water vapor into a reforming pipe 9 arranged in the reformer 1,
A heat exchanger 30 is provided so that heat can be exchanged with the second conduit 16 that leads the reformed gas from the reforming pipe 9 to the outside of the device. Further, the conduit 16 is provided with a bypass pipe 31 with the heat exchanger 30 sandwiched therebetween, an automatic control valve 32 is provided at a portion entering the heat exchanger 30 from the conduit 16, and the bypass pipe 31 is provided with an automatic control valve. 33 are provided. Further, a temperature detector 34 is arranged near the inlet of the reformer 1 of the conduit 13, a controller 35 is connected to the temperature detector 34, and a controller 35.
Is connected to the automatic control valves 32 and 33, and the automatic control valves 32 and 33 are
Is configured so that it can be proportionally controlled.

In the reformer apparatus of the present embodiment having such a configuration, as shown in the system diagram of FIG. 2, a mixed gas of natural gas sent from the conduit 17 and steam sent from the conduit 18 (approximately (200 ° C.) enters the heat exchanger 19 and receives heat from the pipe 20 through which the high temperature gas passes, and the temperature rises by one step. further,
This mixed gas is sent to the heat exchanger 30 and receives heat from the conduit 16 passing through the high-temperature reformed gas (about 590 ° C.) sent out from the reforming pipe 9, and the temperature thereof is significantly increased. On this occasion,
With the temperature detector 34 provided near the inlet of the reformer 1 of the conduit 13, the gas temperature at this portion is suitable for the reforming reaction.
The temperature is maintained within the range of 427 to 510 ° C, and the automatic control valves 32, 3 are controlled by the controller 35 linked to this temperature detector 34.
The heat exchange of the heat exchanger 30 is controlled by controlling 3 proportionally.

On the other hand, the reformed gas which has been reformed into the hydrogen-rich gas in the reformer 1 is controlled to be about 593 ° C. at the outlet of the reforming pipe 9, and further heat is taken in the heat exchanger 30. Because it will be
The temperature of the reformed gas after passing through the heat exchanger 30 is lowered, sent to the heat exchanger 21, and lowered by the cooling pipe 22 to an appropriate temperature (about 430 to 450 ° C.) which enters the high temperature shift converter 23. In this way, the reformed gas whose temperature is controlled is heated in the high-temperature converter 23 by carbon monoxide CO
After being converted into carbon dioxide CO _2, it is sent to a fuel cell (not shown) through a low-temperature converter (not shown) and contributes to power generation.

As described above, in the reformer device of the present invention, by disposing the temperature detector 34, highly accurate temperature control can be performed, and efficient heat exchange is possible, so that significant energy saving is realized. it can.

The reformer device of the present invention is not limited to the above embodiment, and the heat exchanger 30 may be arranged in the reformer 1. Further, by increasing the heat exchange rate of the heat exchanger 30, the conventionally used heat exchanger 19 may be omitted.

As described above, according to the present invention, the temperature control of the reaction gas in the reformer device can be accurately and easily performed.
Further, since efficient heat exchange can be performed, there is an effect that it is possible to provide a reformer device capable of saving energy. In particular,
Although not generally required for a reformer, there are the following performances unique to a fuel cell reformer.

In the fuel cell, the amount of fuel required changes according to the load of the cell, and the amount of the raw material gas (reforming hydrocarbon-based gas) for producing the reformed gas serving as the fuel changes accordingly. Therefore, a rapid response of the temperature control in the reformer to the amount of reformed gas in the reformer is desired.

Fuel cells are vulnerable to fuel shortages and have a great impact on cell characteristics. Therefore, the uniform supply of the reformed gas used as the fuel is desired more than that of a general reformer.

In response to these requirements, in the present invention, the temperature of the inlet is controlled so as to be kept constant. Therefore, in order to keep the temperature of the reformer constant, the heat source can be obtained by simply looking at the endothermic amount that changes according to the reaction amount. All you have to do is control the burner. According to the present invention, which requires only simple control as described above, the temperature inside the reformer with respect to the reaction amount can be easily and quickly made to follow, even in the case of the reformer for a fuel cell in which the load fluctuation is severe as described above. be able to.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing an embodiment of the reformer device of the present invention, FIG. 2 is a system diagram thereof, FIG. 3 is a longitudinal sectional view showing a conventional reformer device, and FIG. FIG. 5 is a cross-sectional view of a conventional reformer device. 1 …… Reformer, 2,3 …… Conduit, 4 …… Main burner, 5,6…
… Conduit, 7 …… Auxiliary burner, 8 …… Combustion chamber, 9 …… Reformer tube, 10 …… Conduit, 11 …… Ceramic sphere, 12 …… Exhaust gas pipe, 13 …… Conduit, 14 …… Catalyst, 15 , 16,17,18 …… Conduit, 1
9 …… Heat exchanger, 20 …… Tube, 21 …… Heat exchanger, 22 ……
Tube, 23 …… High temperature transformer, 30 …… Heat exchanger, 31 …… Bypass pipe, 32,33 …… Automatic control valve, 34 …… Temperature detector, 35…
… Controller.

Claims (2)

[Claims] 1. A reforming pipe for allowing a mixed gas of a hydrocarbon-based gas to be reformed and steam to flow therethrough to reform it into a hydrogen-rich reformed gas by a catalytic action, and heating control of this reforming pipe. A reformer for a fuel cell, comprising: a heating burner for introducing a mixed gas of the hydrocarbon gas to be reformed and steam into the reforming tube; A second conduit for leading the reformed gas further, a heat exchanger for exchanging heat between the first conduit and the second conduit, and a second conduit for branching the heat exchanger. A bypass pipe provided so as to bypass and communicate with the exchanger; and an automatic control valve provided in the bypass pipe and the second conduit for adjusting the flow rate of the reformed gas flowing inside each pipe, The temperature of the mixed gas in the vicinity of the inlet of the first conduit into the reformer And a controller for controlling the heat exchange of the heat exchanger by adjusting the automatic adjustment valve to control the temperature of the mixed gas detected by the temperature detector to be a predetermined value. A reformer device for a fuel cell, comprising: 2. The reformer device for a fuel cell according to claim 1, wherein the heat exchanger is arranged in the reformer for the fuel cell.