JPS6311501A - Reforming device - Google Patents

Abstract

PURPOSE:To uniformize the temp. distribution in a circumferential direction throughout a reforming reactor while enhancing the heat-exchange efficiency between the reforming reactor and the combustion gas by providing a guide vane at the bottom of a reforming furnace for the gaseous fuel of a fuel cell. CONSTITUTION:A burner 2 is provided at the top of a cylindrical furnace casing 1 in the reformer, and an inner tube 3 is furnished to surround the peripheral region of the burner 2 and to form a burner combustion chamber 4. The reforming reactor 8 communicating with the burner combustion chamber 4 is provided in an ascending gas passage 6 formed between the inner tube 3 and the outer tube 1b of the furnace casing 1. Besides, the guide vane 11 for imparting a spiral flow (B) in the direction of the inner periphery of the furnace to the combustion gas flowing to the ascending combustion gas passage 6 side through the vane is furnished in the vicinity of the bottom in the furnace casing.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention relates to the configuration of a fuel gas reformer 1 which is incorporated into a fuel cell power generation plant.

[Prior art and its problems]

In order to supply fuel gas to a fuel cell using methanol or the like as a reforming raw material, it is necessary to gasify the raw material such as methanol and then further reform it into a hydrogen-rich gas. is equipped with a reformer. Here, the general structure of a conventional methanol reforming device is shown in FIGS. 5 and 6. In FIG. is provided with an inner cylinder 3 that surrounds the circumferential area of the burner 2 and extends to near the bottom plate 1a of the container.With this inner cylinder 3 as a partition wall, the combustion chamber 4 of the burner 2 is located on the inner peripheral side, and the combustion chamber 4 of the burner 2 is located on the outer peripheral side. A fuel gas ascending passage 6 whose terminal end communicates with the combustion gas discharge pipe 5 is defined between the outer cylinder 1b of the furnace body 1 and the outer cylinder 1b of the furnace body 1. Further, a reforming reactor 8 having a cylindrical structure filled with a reforming catalyst 7 is disposed inside the combustion gas rising passage 6, and a reforming raw material supply pipe 9 is provided at the lower end of the reactor 8, and a reforming raw material supply pipe 9 is provided at the upper end of the reforming reactor 8. The reforming reactor, to which the reformed gas outlet pipe 10 is connected, may be composed of a plurality of reforming reaction tubes lined up on the circumference. By combusting the fuel supplied to the burner 2 in this configuration, the high-temperature combustion gas descends in the burner combustion chamber 4 in the direction of the dotted arrow, and when it reaches near the bottom plate of the furnace body 1, the flow direction is reversed. The combustion gas rises in the combustion gas rising passage 6, and after exchanging heat with the reforming reactor 8 during this process, it is exhausted to the outside of the system through the gas exhaust pipe 5. On the other hand, by supplying reforming raw materials such as methanol to the reforming reaction 88 installed in the furnace through the constitutional raw material supply pipe 9, the raw materials are vaporized in the process of flowing through the pipes in the furnace and then sent to the reforming reactor 8. In the process of flowing upward in the reforming reactor, it catalytically reacts with the reforming catalyst in the presence of water vapor and is reformed into a hydrogen-rich gas,
It is then discharged through the outlet pipe 10. As is well known, the reforming reaction is an endothermic reaction, and the amount of heat required for the reaction to proceed is provided by heat exchange between the combustion gas flowing in the furnace and the reforming reactor. Also the said modification! When used in a fuel cell power generation plant, the off-gas of the fuel gas discharged from the fuel cell is normally used as the fuel supplied to the burner 2, and the reformed gas obtained here is used as the fuel gas. Supplied to the battery. By the way, when a reformed Ir device is incorporated into a fuel cell power generation plant as described above, in order to increase the overall efficiency of the power generation plant, it is necessary to improve not only the reforming efficiency but also the thermal energy exchange efficiency in the reformer. This is an extremely important issue. To address this problem, conventional methods to improve heat exchange efficiency include attaching fins to the reforming reactor to increase its heat transfer area, and installing baffles around the reforming reactor to disrupt the flow of combustion gas. There are known methods for improving the heat transfer characteristics between the reforming reactor and the reforming reactor. However, with these methods, in reality, the combustion gas flow in the furnace becomes uneven due to dimensional errors, distortions, etc. in the manufacturing of the reformer. A uniform temperature distribution could not be obtained, and actual tests conducted by the inventors showed that there was a temperature difference of 100° C. or more between high-temperature areas and low-temperature areas. Moreover, if the temperature distribution becomes uneven in the reforming reactor in this way, the progress of the reforming reaction will not only become uneven, making it impossible to obtain high reforming efficiency, but also cause the reforming catalyst to be partially overloaded. As a result, its lifespan will be significantly reduced. In addition, as an improvement measure to eliminate the above-mentioned variation in temperature distribution, a spiral ventilation guide is installed in the combustion gas rising passage shown above, and the combustion gas flowing therein is swirled in the circumferential direction. A method has been proposed in which the temperature distribution in the circumferential direction is made uniform, but such a method complicates the structure and significantly increases the manufacturing cost of the device. There are drawbacks such as the obstruction that makes maintenance and inspection of the reforming reactor difficult.

[Purpose of the invention]

This invention was made in consideration of the above points, and it solves the difficulties of the conventional method described above, and provides a reforming reactor and a reforming reactor placed inside the furnace with a simple structure that requires only a few additional members installed inside the furnace. It is an object of the present invention to provide a configuration of a reformer 1 tvt position that can increase the heat exchange rate with the combustion gas and at the same time make the temperature distribution in the circumferential direction uniform throughout the reforming reactor.

[Key points of the invention]

In order to achieve the above object, the present invention provides a guide vane near the bottom of the furnace body that imparts a swirling flow in the direction of the inner circumference of the furnace to the combustion gas flowing toward the combustion gas rising passage through the contact part. By making the combustion gas flow flowing through the combustion gas rising passage where the reforming reactor is installed into a swirling flow, the heat exchange efficiency between the combustion gas and the reforming reactor is increased, and the heat exchange efficiency is increased in the circumferential direction. This is to eliminate variations in temperature distribution.

[Embodiments of the invention]

1, 2, 3, and 4 respectively show the configurations of different embodiments of the present invention, and FIG.
Identical members corresponding to FIG. 6 are given the same reference numerals. The basic structure of the modified '11r device in each embodiment is shown in Figures 5 and 6.
In the embodiment shown in FIGS. 1 and 2, a guide vane designated by reference numeral 11 is provided at the center of the bottom of the furnace body l. 2
As clearly shown in the figure, it has a structure in which a plurality of blades 12 curved in the same direction are combined radially. Note that the guide vane 11 is not limited to the illustrated structure, and various types can be adopted. On the other hand, by installing such a guide vane 11,
After the combustion gas burned in the burner 2 flows down the combustion chamber 4, the direction is reversed from near the bottom of the combustion chamber 4, and in the process of moving to the combustion gas 1 well passage 6, a swirling flow is imparted by the guide vane 11, and the flow passes through the guide vane 11. On the downstream side, the combustion gas becomes a swirling flow and rises while swirling in the circumferential direction in the combustion gas rising passage 6 between the inner cylinder 2 and the outer cylinder 1b of the furnace body 1, as shown by the dotted arrow B, and During this ventilation process, the peripheral surface of the reforming reactor 8 is washed to perform heat exchange. This increases the heat exchange rate between the combustion gas and the reforming reactor 8 compared to the case where the combustion gas rises almost linearly in the passage 6 as in the conventional configuration shown in FIGS. 5 and 6. Moreover, since the combustion gas flows in the circumferential direction, the entire circumferential area of the reforming reactor 8 is heated evenly, and the temperature distribution in the circumferential direction can be made uniform. Regarding this point, the inventor has determined that the outer diameter of the furnace body l is 250 mm,
An actual machine test was conducted on a reformer with an inner cylinder 2 diameter of 150 mm, and it was found that the difference in temperature distribution around the entire circumference of the reforming reactor 8 was within about 20°C at most. has been confirmed. Inside the reforming reactor 8, the endothermic reaction of methanol decomposition takes place in the first half of the raw material supply side, that is, in the lower part near the guide vanes 11, so the swirling flow of the combustion gas mentioned above is particularly effective for the progress of the reforming reaction. It comes to work effectively. Next, the embodiment shown in FIGS. 3 and 4 is a further improvement of the above embodiment, in which the guide vane 11 is located at the bottom 47i of the furnace body
It is installed on a conical conical surface part 1c formed in the center of 1a so as to be convex toward the inside of the furnace. With this configuration, the combustion gas descending within the burner combustion chamber 4 changes direction while flowing along the conical surface of the conical surface portion 1c, reducing the pressure loss of the combustion gas flow, and the guide vane 1
In conjunction with 1, swirling flow can be more effectively imparted to the combustion gas.

【Effect of the invention】

As described above, according to the present invention, a guide vane is provided near the bottom of the furnace body for imparting a swirling flow in the direction of the inner circumference of the furnace to the combustion gas flowing through the core and toward the combustion gas rising passage. With this configuration, it is possible to improve the heat exchange efficiency between the reforming reactor and the combustion gas flow, and to make the temperature distribution uniform in the circumferential direction. Furthermore, as a result, the reforming reaction proceeds uniformly throughout the entire area within the reforming reactor, eliminating the need to place an extreme load on a portion of the reforming catalyst, thereby extending the life of the reforming catalyst. In addition, when the reformer is incorporated into a fuel cell power generation plant, there are advantages such as its high reforming efficiency and energy saving effect, which can greatly contribute to improving the overall efficiency of the power generation plant.

[Brief explanation of drawings]

1, 2, 3, and 4 are longitudinal and transverse sectional views showing the structure of a reformer according to different embodiments of the present invention, respectively, and FIGS. 5 and 6 are views of a conventional reformer. FIG. 1 is a vertical cross-sectional view and a cross-sectional view showing the configuration of a reformer. In each figure, l: furnace body, la: bottom plate, lb: outer cylinder, lc:
Conical surface part, 2: Burner, 3: Inner cylinder, 4: Burner combustion chamber, 6
: Combustion gas rising passage, 7: Reforming catalyst, 8: Reforming reactor,
9: Reformed raw material supply pipe, 10: Reformed gas outlet pipe, 11 guide vane, A, B: combustion gas flow. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1) For a cylindrical furnace body equipped with a burner at the top, an inner cylinder is provided in the furnace to surround the peripheral area of the burner and define a burner combustion chamber, and the inner cylinder In the reformer, the reforming reactor is disposed in a combustion gas rising passage defined between the burner combustion chamber and the outer cylinder of the furnace body, and the reforming reactor is disposed in the combustion gas rising passage defined between the burner combustion chamber and the outer cylinder of the furnace body. A reforming device characterized in that a guide vane is provided for imparting a swirling flow toward the inner circumferential direction of the furnace to the combustion gas flowing through the passage toward the combustion gas rising passage. 2) The reformer according to claim 1, characterized in that the guide vane is installed on a conical surface part formed at the center of the bottom plate of the furnace body and convex toward the inside of the furnace. reformer.