JPS6274448A - Reformer of fuel cell - Google Patents

Abstract

PURPOSE:To enhance reforming reaction efficiency, by providing a heat exchanger performing the heat-exchange of high temp. combustion exhaust gas with reforming gas to the outer peripheral part of a reformer while providing a gas distribution plate having a large number of perforations in the heat exchanger. CONSTITUTION:A gaseous mixture consisting of stock gas and steam is uniformly fallen through a heat exchanger 24 to be raised in its temp. through heat exchange and flows in a chamber equipped with a gas distribution plate 31 having a large number of perforations 32 while the distributed gas streams are gathered to be introduced into a reforming pipe 9 through a conduit 13. The gaseous mixture entering the reforming pipe 9 passes through the packed catalyst bed in the reforming pipe 9 to enter the conduit 15 at the part inside the top part of said pipe 9 and the hydrogen rich reforming gas is guided to the outside of a reforming container 1 from the conduit 15 communicated with said conduit 15 to be introduced into the heat exchanger 24. Said reforming gas is heat-exchanged with the gaseous mixture consisting of the stock gas and steam and further passed through a heat exchanger 21 and a high temp. transformer 23 to be further supplied to a fuel cell through a low temp. transformer.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a hydrocarbon system that is introduced into a reforming tube using reformed gas and combustion exhaust gas flowing out from the reforming tube in a reformer container. The present invention relates to a fuel cell reformer device 5 in which a reforming reaction can be efficiently promoted by raising the temperature of a mixed gas of raw material gas and water vapor to an appropriate temperature in a heat exchanger.

[Technical Background of the Invention] In recent years, fuel IE ponds have been attracting attention and expectations from research into their development and practical application. This is a device that directly converts the energy released along with C2 into electrical energy C2.

Even on a relatively small scale, a power generation plant using fuel cells has a thermal efficiency of 40 to 50% CU, and is expected to far exceed new thermal power generation.

In addition, emissions of sulfur oxides and nitrogen oxides, which are pollution factors that have become a major social problem in recent years, are extremely low. Furthermore, since the power generation device does not include a combustion cycle, it does not require large amounts of cooling water and generates little vibration noise, so it can be expected to have high energy conversion efficiency in principle, as well as reduce environmental problems such as noise and exhaust gas. In addition, C-yu has the advantage of good responsiveness to load fluctuation C-yu. In a power generation plant using such a fuel cell, hydrogen gas obtained by mixing water vapor with hydrocarbon-based raw material gas such as natural gas and heating it in a reformer is mixed with hydrogen gas from other systems. turbo·
In many fuel cells, air from a compressor is supplied to each fuel cell to cause an oxidation reaction, and electricity is obtained from each unit.

Fig. 5 is a system diagram showing an example of a reformer installed in this type of fuel cell power generation plant, and Fig. 6 is a longitudinal cross-sectional view of an SX example of the reformer main body in Fig. 5 C2. FIG. 7 is a plan view of FIG. 6. In the figure, inside the reformer container 1 is a main burner that introduces fuel from a conduit 2 connected to a fuel tank (not shown) and air from a conduit 3 connected to an air supply machine (not shown), mixes the mixture, and burns the mixture. In addition, fuel is introduced through a conduit 5 and air is introduced through a conduit 6, respectively, and an auxiliary burner 7 for igniting the main burner 4 having an electric ignition device is provided. The high-temperature combustion exhaust gas from the main burner 4 flows through the heating chamber 8, passes through the outer circumferential space of the reforming tube 9 having an annular cross section, and passes through the ceramic bulb 1 in the lower layer.
1, and is further discharged to the outside of the reformer container 1 through an exhaust gas pipe 12 communicating with the conduit 10,
On the other hand, a mixed gas of hydrocarbon-based raw material gas such as natural gas and steam is introduced from the conduit 13 and is operated by the reforming pipe 9.
The reforming catalyst layer (hereinafter referred to as single catalyst 114) 1
Pass through the conduit holding 4. During this passage, a reforming reaction takes place due to heating and catalytic action, and the gas is reformed into hydrogen-rich gas. This reformed gas is led to the outside of the reformer vessel l via a conduit 15 in the reforming tube 9 (and via four pipes 16 connected thereto), and is lowered in temperature by a heat exchanger 21. As a result, the carbon monoxide contained in the reformed gas is converted into carbon dioxide through the high-temperature shift converter 23 and the low-temperature shift converter (not shown), and is supplied to the fuel cell (not shown) and contributes to the generation of carbon dioxide. .

[Problems with the background art] By the way, as this type of device, for example, Japanese Patent Laid-Open No. 53-79
No. 767 is known. Reformer C as described above
Second, the temperature of the mixed gas of raw material gas and steam on the input side of the reforming tube 9 needs to be controlled at 427° C. or higher and 510° C. or lower. The reason for this is that when the temperature falls below 427 degrees Celsius (141), polypropylene deposits on the catalyst layer 141, deteriorating the performance of the catalyst, and when the temperature rises above 510 degrees Celsius, the mixed gas decomposes and generates carbon, which is deposited on the catalyst layer. This is because the catalyst enters the structure of the reformer container 1, destroys the catalyst, turns it into powder, and increases the differential pressure inside the reformer tube 9. The mixed gas of raw material gas and water vapor introduced from the bottom rises through the catalyst layer 14 in the reforming tube 9, and its temperature rises to cause a reaction of reforming into hydrogen gas at 760°C or higher. , the reformer vessel 1 (7) so that the temperature at the top of the reformer tube 9 reaches the maximum of 982°C.
The main burner 4 controls the heating of the reforming tube 9.

In addition, the hydrogen-rich gas reformed from C2 flows down the conduit 15 inside the top of the reforming tube 9 and transfers heat to the catalyst layer 14, and on the exit side of the reforming tube 9, approximately The temperature was controlled at 593°C.

On the other hand, the gas reacted and reformed in the reforming tube 9 contains -carbon oxide CO, which is harmful to the battery body C. The gas temperature is reduced to about 593°C by the cooling gas in the conduit 22 in the heat exchanger 21 to a range of 387°C to 421°C, and then introduced into the high temperature shift converter 23 where it is monoxidized by the catalytic reaction C. Converts carbon CO to carbon dioxide CO2. The basic reforming reaction formula of raw material gas and steam mixed gas is shown below.

Reaction inside the reforming tube CH4+ 2H2+ heat → Co + H
20+ 3H2 Reaction in high temperature shift converter Co + H2O
-*Heat+CO2+H2 From the above explanation, in order to reform the mixed gas of raw material gas and steam into a hydrogen-rich gas in the catalyst layer 14 filled in the reforming tube 9, it is necessary to
- The mixed gas of raw material gas and water vapor is between 427°C and 51°C.
It can be seen that heating must be carried out efficiently to maintain an appropriate temperature in the range of 0°C. And the temperature of the gas reformed in the reforming pipe 9 is set at about 593°C to the high temperature shift converter 23.
It can be seen that the appropriate temperature for introduction must be lowered to a range of 387°C to 421°C.

However, in conventional reformers, the temperature of the mixed gas of natural gas and steam is about 200°C through the heat exchanger 19 (: the reforming tube 9
The temperature must be raised to an appropriate temperature range of 427°C to 510°C in order to introduce the heat into the heat exchanger 19. C; It is difficult to control the temperature due to the heat loss due to the need to provide a large amount of thermal energy and the large difference in temperature between heat transfer and reception in the heat exchanger 19. There was a problem.

Furthermore, the temperature of the gas discharged from the first reforming pipe 9 is approximately 593°C.
Heat exchanger 21C: Suitable temperature range of 387°C to 421°C for introducing heat into the high-temperature transformer 23 (heat loss that releases a large amount of thermal energy to lower the temperature, and temperature control due to the large temperature difference during heat exchange) There are some problems that can be difficult.

[Objective of the Invention] The present invention has been made to solve the above-mentioned problems, and its purpose is to efficiently carry out the reforming reaction and to save energy. Inside the reformer tube C: A reformer device that can easily control the temperature of the mixed gas of raw material gas and steam introduced and the temperature of the reformed gas discharged from the reformer tube at an appropriate temperature C and also save energy. There are two things to offer.

"Summary of the Invention" In order to achieve the above object, the present invention provides the above-mentioned reforming pipe interior C: a mixed gas of raw material gas and water vapor to be introduced, and a high-temperature combustion exhaust gas after passing through the outside of the reforming pipe, A heat exchanger for exchanging heat with the reformed gas discharged from the reforming tube in the same heat exchanger is provided on the outer circumferential side of the reformer, and the C gas flow within the heat exchanger is evenly distributed. The first feature is that a gas distribution plate having a large number of holes is provided, and in addition to this C1, a first bypass guides the burner combustion exhaust gas discharged from the reformer to the outside of the reformer container. and a second bypass pipe that branches from the first bypass pipe from the inlet side of the heat exchanger and connects to the first bypass pipe through the heat exchanger, and the raw material gas introduced into the reforming pipe is provided. and a temperature detector for detecting the temperature of the mixed gas of water vapor, a first control valve provided in the first bypass pipe to adjust the flow rate of the reformed gas in the pipe, and the second bypass pipe C; A second control valve that adjusts the flow rate of the reformed gas in the pipe, and a second control valve that compares the detected temperature from the temperature detector and a specified mixed gas temperature, and according to the comparison result, the first control valve and a controller for controlling the opening degree of the second control valve.

[Embodiments of the Invention] Hereinafter, two embodiments of the present invention will be described with reference to the drawings. Fig. 2 shows a longitudinal cross-sectional view of an example of the structure of the reformer device, Fig. 3 shows a plan view of an example of the structure of the reformer device, and Fig. 4 shows an example of the structure of the reformer device in a plan view. FIG. 5 is an explanatory diagram of a gas distribution plate in a heat exchanger according to the present invention.
Components that are the same as those of the conventional type in FIGS. 6 and 7 are designated by the same reference numerals.

1, 2, 3, and 4C, a main burner 4 is provided at the top of the reformer vessel 1, and its combustion port is located at the inner side g of the reformer vessel 1. In addition, an auxiliary burner 7 having a combustion nozzle C and an electric ignition device is arranged so as to be able to ignite the main burner 4. In the lower part f2, a plurality of reforming tubes 9 having an annular cross section are arranged at equal intervals.The high temperature combustion exhaust gas combusted in the main burner 4 passes through the reforming tubes 9 by changing the intervals between the plurality of reforming tubes 9. Flow down while heating, and pass through the reforming pipe 9.
Lower outer periphery (: conduit 10 filled with ceramic balls 11
The conduit 12 is discharged from the reformer container 1 through a communicating conduit 12, and the conduit 12 branches into two directions outside the reformer container 1. The bypass pipe 25 contributes to the operation of a turbo compressor (not shown) for utilizing exhaust gas heat through an automatic control valve 27 to discharge exhaust gas. On the other hand, a second bypass pipe 26 branched from the inlet side of the heat exchanger 24 from the conduit 12 is connected to the reformer vessel 1.
The area is provided so that it is connected to the first bypass pipe 25 via a heat exchanger 24 provided on the outer peripheral wall C2, and further via an automatic control valve 28 on the downstream side of an automatic control valve 27 provided in the first bypass pipe 25. be. On the other hand, the mixed gas of hydrocarbon-based raw material gas and water vapor is passed from the conduit 13 to the upper part C2 of the heat exchanger 24, on the outflow side C: equipped with a gas distribution plate 31 having a large number of holes 32. The above-mentioned introduced gas is introduced into the chamber so that it flows down evenly through the holes 32 of the flow dividing plate 31. The high temperature reformed gas is transferred to a heat exchanger 24.
This gas is introduced from the lower part of the heat exchanger 24 into each chamber C2 equipped with a gas flow divider plate 31 having several holes 32 on the outlet side provided at the lower part of the heat exchanger 24. ]
The mixed gas of the raw material gas and water vapor flows upward through the holes 32 and passes through the inner peripheral side and outer peripheral side of the downward flow of the mixed gas, exchanging heat with the gas, and flows upward to the upper part C of the heat exchanger 24. The tail f2, which is split into two and is equipped with a flow divider plate with a large number of holes 32 at the inflow part, flows into the conduit 12 and the conduit 1.
61 units are connected to each other.

The mixed gas of the raw material gas and water vapor flows down the heat exchanger 24 evenly and undergoes heat exchange to raise the temperature and pass through the lower part of the heat exchanger 24 (: the inlet section provided with a large number of holes 32). The gas flows into the chamber 1 equipped with a flow divider plate, and the gas collects in the conduit 1.
3 to be introduced into the reforming tube 9. Then, the mixed gas introduced into the reforming tube 9C2 passes through the catalyst layer 14 filled with the inside of the reforming tube 9, enters the conduit 15 inside the top of the reforming tube 9, and enters the conduit 15 (which is in communication with Hydrogen-rich reformed gas is guided to the outside of the reformer container 1 through the conduit 16, introduced into the heat exchanger 241, and exchanged with the mixed gas of the C2 raw material gas and steam as described above, and then transferred to the ζ2 heat exchanger. 21 and a high-temperature transformer 23, and is further supplied to the fuel cell via a low-temperature transformer (not shown).

Further, the automatic control valve 27 and the group are connected to a temperature detector 29i of the mixed gas of raw material gas and steam at the conduit portion introduced into the reforming pipe 9.
-C to perform proportional control in conjunction with the automatic controller 30.
I'm doing it. That is, the detected temperature from the temperature detector 29 is compared with a specified mixed gas temperature (427 to 510°C), and if the detected temperature as a result of the comparison is lower than the specified mixed gas temperature, the control valve 28 is opened. The control valve 27 is controlled in the closing direction, and conversely, when the detected temperature j■ is higher than the specified mixed gas temperature, the control valve 27 is controlled in the opening direction.
8 in the closing direction.

In the reformer device t configured as described above, a mixed gas of raw material gas and steam is supplied to the reformer container 1 from the conduit 13i.
It is introduced into a heat exchanger 24 provided on the outer peripheral side. On the other hand, combustion gas is combusted from the main burner 4, and the high-temperature combustion exhaust gas flows down the reformer tube 9 while heating it, and a part of it is introduced into the heat exchanger 24 through the conduit 12. moreover,
The reformed gas that has undergone an exothermic reaction in the reforming tube 9 is introduced into the conduit 16C2 and enters the heat exchanger 24, and then passes through the conduit 13 as shown in FIG.
In the heat exchanger 24f, the gas mixture is surrounded by conduits 12 and 16 from the inside and outside, and is further provided with a gas distribution plate 31 having a large number of holes 32 on the gas inlet and outlet sides. It becomes possible to raise the temperature to the appropriate temperature required.

Furthermore, the reforming pipe 9C: The temperature of the mixed gas of raw material gas and steam introduced is not detected by the temperature detector 29, and when the temperature is higher than the appropriate temperature, an automatic controller linked to the temperature detector 29 30, the opening degree of the automatic control valve 27 increases, and it is controlled inversely proportionally to the automatic control valve 27.
8, the opening degree becomes smaller. This control C: from burner 4
Regarding the amount of combustion exhaust gas, the flow rate through the heat exchanger 24 is reduced, the heating energy for the mixed gas is reduced, and the temperature rise is reduced.

Further, when the temperature detected by the temperature detector 29 is lower than the appropriate temperature, the opening degree of the automatic MEII control valve 27 is similarly reduced three times, and then the automatic control valve 27 is controlled in inverse proportion.
An opening of 8 makes it sound like a dog. Due to this control, the temperature of the mixed gas rises in the heat exchanger 24 (Y). Through the above control, the mixed gas of raw material gas and steam introduced into the reforming tube 9 It becomes possible to maintain an appropriate temperature.

On the other hand, the gas reformed by the reforming pipe 9 is transferred to the heat exchanger 24.
In order to lower the temperature by exchanging heat with the high-temperature transformer 23, in the heat exchanger 21 provided, the cooling gas 22 is cooled to an appropriate temperature before being introduced into the high-temperature transformer 23. It is possible to reduce energy consumption. Furthermore, since the heat exchanger 24 surrounds the outer circumferential side of the reformer vessel 1, heat radiation from the outer circumferential side of the reformer vessel 1 can be prevented, so the combustion amount of the combustion burner 4 is reduced and energy is It is possible to reduce the

As described above, according to the reformer device having this configuration, the heat exchanger 24 is provided along the outer circumferential side of the reformer container 1 (along the y), and several stripes are provided at the gas inlet and gas outlet of the heat exchanger 24. hole 3
2, the temperature of the mixed gas of hydrocarbon-based raw material gas and steam introduced into the reforming tube 9 can be easily controlled for reforming (required appropriate temperature 1 unit). Therefore, the reforming reaction to produce a hydrogen-rich gas can be carried out extremely efficiently (and energy saving can be achieved).In addition, the temperature of the reformed gas discharged from the reforming tube 9 can be lowered. Since the temperature decreases in the heat exchanger 24,
The temperature of the reformed gas introduced into the heat exchanger 21 on the inlet side of the high-temperature shift converter 23 is lowered, making it possible to facilitate temperature control and save energy in the same way as described above. [Effects of the Invention] As explained above. According to the present invention, a mixture of raw material gas and steam introduced into the reforming tube, high-temperature combustion exhaust gas after passing through the outside of the reforming tube, and reformed gas discharged from the reforming tube. A heat exchanger equipped with a gas distribution plate for exchanging heat with the gas is provided on the outer peripheral side of the reformer container, and in addition, the high temperature combustion exhaust gas inside the reformer container is transferred to the heat exchanger. A conduit for guiding high-temperature combustion exhaust gas to the outside of the reformer vessel after passing through the introduction a, and a bypass branching from the inlet side of the heat exchanger of this conduit and communicating with the outlet side of the heat exchanger of the conduit. A temperature detector for detecting the temperature of the mixed gas of raw material gas and water vapor introduced into the reforming tube ζ2, and a combustion exhaust gas flow line in the pipe which is divided into two on the heat exchanger side C of the conduit. The first to adjust
Compare the control valve @2 provided in the bypass pipe to adjust the flow rate of combustion exhaust gas in the pipe, the detected temperature from the temperature detector and the specified mixed gas temperature, and the comparison result. Since the structure is equipped with a controller that controls the opening degrees of the first control valve and the second control valve, respectively, according to
Extremely reliable, it can save energy and easily control the temperature of the mixed gas of raw material gas and steam introduced into the reforming tube and the temperature of the reformed gas discharged from the reforming tube to an appropriate temperature. A reformer device with high performance can be provided.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the reformer device of the present invention;
Fig. 2 is a longitudinal sectional view showing the reformer device, Fig. 3 is a plan sectional view showing the reformer device, and Fig. 4 is an explanatory diagram of the gas distribution plate in the heat exchanger according to the present invention. , FIG. 5 is a system diagram showing a conventional reformer device, FIG. 6 is a longitudinal sectional view showing a conventional reformer main body, and FIG. 7 is a plan sectional view of FIG. 6. 1... Reformer container 4... Main burner 7...
Auxiliary burner 9...Reforming tube 1]...Ceramic bulb 14...Catalyst layer 21...Heat exchanger 2
3... High temperature transformer 24... Heat exchanger 27.
28... Automatic control valve 29... Temperature detector 30
... Automatic controller: 31 ... Gas distribution plate agent Benkishi Nori Chika Ken Yudo Hirofumi Mitsumata Figure 4 Figure 5 Figure 6 Figure 7

Claims (2)

[Claims] (1) A plurality of reforming tubes each having an annular cross-section, one end of which is sealed and a reforming catalyst layer provided inside, are arranged inside the reformer container, and combustion gas and combustion air are supplied to the burner. The high-temperature combustion exhaust gas obtained by combustion is caused to flow from one end of the reforming tube through the outside to the outside from the other end, and a mixed gas of raw material gas and water vapor is allowed to flow in from the other end of the reforming tube. In a reformer configured to be reformed into reformed gas through a reforming catalyst bed and further flowed out from one end through an inner pipe and the other end, a mixed gas of raw material gas and water vapor introduced into the reforming pipe. and a heat exchanger for exchanging heat between the high-temperature combustion exhaust gas that has passed through the outside of the reforming tube and the reformed gas discharged from the reforming tube, is provided on the outer peripheral side of the reformer container, A fuel cell reformer device characterized in that a gas flow dividing plate having a large number of holes is provided at an inlet portion and an outlet portion of the heat exchanger. (2) A conduit for introducing the high-temperature combustion exhaust gas inside the reformer container into the heat exchanger and guiding the high-temperature combustion exhaust gas after passing through the same to the outside of the reformer container, and an inlet of this conduit to the heat exchanger. a temperature detector for detecting the temperature of a mixed gas of raw material gas and water vapor introduced into the reforming pipe, the bypass pipes being branched from the side and communicating with the heat exchanger outlet side of the pipes; a first control valve provided on the heat exchanger exit side of the conduit to adjust the flow rate of combustion exhaust gas in the pipe; a second control valve provided in the bypass pipe to adjust the flow rate of combustion exhaust gas in the pipe; A controller that compares the temperature detected by the temperature detector and a specified mixed gas temperature, and controls the opening degrees of the first control valve and the second control valve, respectively, according to the comparison result. A fuel cell reformer device comprising: