JPS63291802A - Fuel reforming apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel reformer that generates hydrogen by steam reforming hydrocarbons and alcohols such as methanol, and particularly relates to an on-site fuel reformer. The field for battery and semiconductor manufacturing processes relates to a fuel reformer suitable for pure hydrogen production equipment.

[Conventional technology]

Conventional fuel reformers, as typified by the example in Japanese Patent Application Laid-open No. 78983/1983, fill a reaction tube with a reforming catalyst to form a reforming catalyst layer, and remove this reaction tube from the surroundings. The main method was external heat heating using combustion gas or heat medium. In this conventional reaction tube type system, the reaction section where many reaction tubes are arranged and the combustion section for obtaining combustion gas and high temperature heat medium to heat the reaction tubes are independent, so there is no space around one reaction tube. It was necessary to secure a flow path for heating medium such as combustion gas. Therefore, in order to downsize the reformer required for on-site use, it is necessary to efficiently arrange the reaction tubes and reduce the space occupied by the flow paths for heating gas and heat medium. Furthermore, in order to efficiently heat the reaction tube, a combustion catalyst is filled in the gas flow path around the reaction tube, and the combustion catalyst is directly combusted around the reaction tube to obtain a high temperature.
There is a publication. However, even in such a system, as long as the reaction tube is used as a reforming catalyst layer, surplus space will inevitably be created even if the reaction tube is arranged geometrically minutely, and there will be a limit to miniaturization. Further, such a reformer is rarely used alone, but is often used as part of a reforming system such as a fuel cell. For this reason, the fuel reformer, which is a high-temperature device, requires many heat exchangers for heat recovery to be disposed outside to form a reforming system.

Moreover, in the conventional reaction tube type apparatus, as shown in FIG. 2, the heat recovery of the reformer itself has only been considered to the extent that a reformed gas return section is provided in the reaction tube.

[Problem that the invention seeks to solve]

In conventional reaction tube type fuel reformers, it is not possible to eliminate the surplus space created geometrically by making the reaction tube arrangement more compact in response to the demand for smaller devices. There are limits to this. In addition, in order to improve the heating of the reaction tube, it has been considered to fill the area around the reaction tube with a combustion catalyst and move the heat source closer to the reaction tube, but in order to ensure the space for filling the combustion catalyst, it is difficult to simply arrange it closely. is difficult. Moreover,
When a combustion catalyst is used, the excess space is actually filled with catalyst, so a larger amount of catalyst than is required is required. Furthermore, since the main purpose of the conventional apparatus is catalytic reaction, the structure of heat recovery with respect to the apparatus structure is hardly considered as an essential issue. However, recent reformers are required to be more compact as a whole system, and the reformer itself needs a structure that allows it to easily add a heat recovery function.

An object of the present invention is to provide a fuel reformer that allows the reforming system including the fuel reformer to be made more compact.

[Means for solving problems]

The above purpose is to create a catalyst layer structure in which the reforming catalyst is packed in a layered space separated by partition walls, and between these layered reforming catalyst layers, there is a layered flow path where high-temperature gas is generated or passes through as a heating section. The reformer is provided in the same way as the reforming catalyst layer, and the overall structure of the reformer is a laminated structure, eliminating excess space. Furthermore, a gas flow path separated by a partition wall is added to the outside of the reformer. Create a flow path structure suitable for heat exchange with fluids in the heat-requiring system of the quality device. In this way, the fuel reformer becomes a composite device having the function of a heat exchanger, and it is possible to achieve miniaturization of the device and the system.

[Effect]

Filling a layered space separated by partition walls with a reforming catalyst to form a reforming catalyst layer, and similarly configuring the heating section of this reforming catalyst layer with a layered flow path space, these are: They can be stacked to form one reformer. Moreover, by alternately arranging and stacking the reforming catalyst layer, which serves as a heat receiving body, and the heating section, the heat from the heat generating section can be effectively transferred to the reforming catalyst layer, which is the reaction section, without heat loss to the outside. can. In addition, the stacked structure does not have any surplus space like a reaction tube type device, so even if the number of stacked layers is increased and the processing capacity of the device is increased, the surplus space will not increase, and the minimum necessary size will always be maintained. drooping Further, to the reformer having such a laminated structure, a heat recovery section equivalent to a plate heat exchanger can be easily added without impairing the function of the reformer main body. This heat recovery section is
As with the formation of each catalyst layer, flow channels separated by partition walls are simply provided in the reformer body, and the structure of the reformer remains essentially the same. High-temperature combustion exhaust gas or reformed gas generated by the device itself can be flowed in as a heat source, and the reformed raw material or combustion air can be used as a low heat source for heat recovery. Conventionally, such heat recovery was performed using a heat exchanger installed outside the reformer, but in the reformer with this structure, these functions are satisfied only by the equipment itself, so the reformer itself is not required. Auxiliary equipment including surrounding piping can be omitted, making it possible to downsize the device body and the system.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows a cross-sectional view of an embodiment of a fuel reformer according to the present invention. This example illustrates a fuel reformer that has a structure in which one stage of gas flow passages is provided on each side of the reformer main body, which is composed of three stages of reforming catalyst layers and four stages of heating layers. be. Although this embodiment is used as a reformer using methane as a raw material, it is not limited to reforming methane because it can also be applied to reforming alcohols by changing the reforming catalyst 4.

The functions of this embodiment will be described below. The reforming raw material 1 is a mixture of methane and steam, and this ratio is normally 2.5 to 4.5 as a steam carbon ratio (S/C).
Use the value of This reformed raw material is first led to gas channels 6 provided on both sides of the device. In this flow path, since the heating layer is adjacent to one side, the raw material guided to the gas flow path is preheated by receiving heat from the heating layer. The reformed raw material leaving this flow path is
The reforming catalyst bed, which is collected from both sides by the collecting pipe 12 and then distributed and supplied to each reforming catalyst bed, is filled with a nickel-based reforming catalyst 4 for methane reforming. The reformed raw material reacts in this reforming catalyst layer and becomes hydrogen-rich reformed gas 9. Heat is applied from an adjacent heating section so that the reaction temperature at this time is an equilibrium temperature of about 800°C. The heating section of this embodiment has a structure shown in FIG. 1(a). That is, the heating layer is filled with a palladium-based combustion catalyst 3, and three fuel supply pipes 7 are inserted into the combustion catalyst layer. The fuel supply pipe is provided with a large number of nozzle holes in order to uniformly disperse the fuel to the combustion catalyst layer to prevent localized high temperatures due to abnormal combustion. With this heating section structure, the premixed fuel 2 supplied here generates heat through catalytic combustion, and supplies heat to the reforming catalyst layer. The combustion here is a multi-stage combustion consisting of three stages along the flow path direction of the combustion catalyst layer. Therefore, the combustion catalyst layer can maintain an isothermal heat surface with no temperature drop along the flow path direction. Note that the premixed fuel is a mixed fuel of methane and air, but a mixture of anode exhaust gas and cathode exhaust gas containing fuel hydrogen in a fuel cell system may be used. The combustion exhaust gas 8 that has been heated by combustion is discharged from the lower exhaust pipe. As shown in the figure, the structure to satisfy the function of the reformer is such that a partition wall 5 made of a thin heat-resistant material is sandwiched between a casing 14 and the entire structure is supported by an outer wall and fixing bolts. ing. In addition, to protect the outer walls and casing from high temperatures, the inside of each is lined with insulation material. In this embodiment, a small-sized reformer with no surplus space is used. for example,
When designing a fuel reformer for use in a 100 kW class fuel cell, it would be approximately 1.5 m high and 0.9 m wide. This is approximately 115 in volume compared to a conventional reaction tube type device. Furthermore, since the gas channels provided on both sides of the device allow low-temperature reforming raw materials to flow, they also have the effect of shielding the heat from the high-temperature heating section, allowing the insulation layer on the outer wall to be made thinner.

Figure 3 shows an embodiment in which the number of stages of gas flow paths provided on both sides of the reformer is further increased, and the sensible heat of the reformed gas is also recovered and used for preheating the reformed raw material. . Due to this partition wall structure and flow path configuration.

If we consider a fuel reforming system that lowers the temperature of the reformed gas discharged from the reformer and combines it with a fuel cell, it is possible to bring it to a temperature suitable for the next process, the shift reaction. That is, conventionally, as shown in FIG. 5, a heat exchanger was provided between the shift converter and the fuel reformer to lower the temperature of the reformed gas. However, in the structure of this embodiment, these heat exchangers are unnecessary.

Figure 4 shows an example in which the gas flow paths on both sides of the reformer are arranged in three stages to achieve effective heat utilization. It is designed to pass through the flow path.

The effect on the outer wall is similar to that of the embodiment shown in FIG.

FIG. 6 shows a flow path configuration in which four stages of gas flow paths are provided on each side. This uses the head heat of the combustion gas for heat recovery, and corresponds to a reformer that integrates three heat exchangers around the fuel reformer in the fuel cell system shown in Figure 5. . In this case, the flow path configuration is such that gases passing through adjacent flow paths each have a large temperature difference. Therefore, heat transfer between each flow path is effectively performed.

In addition, as in this example, when the number of stages of gas flow paths is increased, these flow paths are used not only for receiving and receiving heat from the reformer itself, but also as a heat exchanger for gas generated by other equipment. You can also do it. For example, the supply air in the embodiment of FIG. 6 may be the cathode wandering air 22 discharged from the fuel cell.

FIG. 7 shows an example of a heat recovery structure when the number of reforming catalyst layers and heating layers is increased.

That is, when the amount of gas generated inside the reformer increases, it becomes difficult to perform these functions using only the gas channels provided on both sides of the reformer. In this case, in this embodiment, self-heat recovery is performed for each catalyst layer. This is similar in structure to the conventional reaction tube type heat recovery method, but since this embodiment uses a planar stacked type, the larger the capacity of the device, the greater the advantage in terms of miniaturization.

〔Effect of the invention〕

According to the present invention, unnecessary surplus space is not generated in the configuration of the device, and it is effective in downsizing the reforming device. Further, heat recovery from the reformed gas and combustion exhaust gas generated in the reformer can be easily performed.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an embodiment of the present invention, Fig. 2 is a sectional view of a conventional reformer, Fig. 3 is a flow path sectional view of an embodiment of the invention, and Fig. 4 is a sectional view of a conventional reformer. FIG. 5 is a flowchart showing an example of a fuel cell system; FIG. 6 is a cross-sectional view of a flow path according to an embodiment of the present invention; FIG. 7 is a cross-sectional view of an embodiment of the present invention. It is. 1... Reforming raw material, 2... Premixed fuel, 3... Combustion catalyst, 4... Reforming catalyst.

Claims (1)

[Scope of Claims] 1. Hydrocarbons and alcohols are used as reforming raw materials, and in order to generate hydrogen-rich gas through steam reforming, the reforming catalyst is filled with a reforming catalyst for supplying and reacting the reforming raw materials. In a fuel reformer comprising a layered reforming section and a heating section that introduces or generates high-temperature combustion gas in order to give heat to the reforming catalyst layer, the reforming section and the heating section are It consists of a laminate of layered spaces each separated by partition walls, and the heating portions and the reforming portions are arranged alternately so that the heating portions are located on both sides of the layered spaces, and the heating portions on both sides are arranged alternately. 1. A fuel reforming device characterized in that layered gas flow paths each separated by a partition wall are provided adjacent to the outside of the fuel reformer. 2. In the fuel reformer according to claim 1, the heating section is a combustion catalyst layer filled with an oxidation catalyst, and the combustion catalyst layer has a plurality of fuel supply pipes arranged in the flow path direction,
A fuel reformer characterized in that the heating section performs multistage combustion. 3. In the fuel reformer according to claim 1 or 2, each of the gas passages is provided in one stage, and the reforming raw material is supplied to the reforming section after passing through the gas passages. A fuel reformer characterized by having a flow path structure. 4. In the fuel reformer according to claim 1 or 2, each of the gas flow paths is provided in two stages, and the inner gas flow path contains a reforming gas before being supplied to the reforming catalyst layer. A fuel reforming device characterized in that a raw material is guided, and the outer gas flow channel has a flow channel structure that guides reformed gas generated in the reforming section. 5. In the fuel reformer according to claim 1 or 2, each of the gas flow channels is provided in three stages, and the reforming raw material is first introduced into the outer gas flow channel, and then into the inner gas flow channel. The intermediate gas flow path includes a flow that guides the reformed gas generated in the reforming catalyst layer. A fuel reformer characterized by having a road structure. 6. In the fuel reformer according to claim 1 or 2, each of the gas flow paths is provided in four stages, and the reforming raw material is
After passing through the gas flow path on the inside, the reformed gas is supplied to the reforming catalyst layer, and the reformed gas generated here is led to the gas flow path on the outside, passes through it, and is then discharged to the outside of the system.
Combustion air to be sent to the heating section passes through the gas flow path in the second stage from the outside and is then premixed with fuel, and the exhaust gas exiting the heating section is guided to the gas flow path in the second stage from the inside. A fuel reformer characterized by having a flow path structure. 7. The fuel reformer according to claim 1 or 2, characterized in that a reformed gas return passage formed by two partition walls is provided in each of the reforming catalyst layers. Fuel reformer. 8. The fuel reformer according to claims 1 to 7, characterized in that the partition wall constituting the gas flow path is provided with heat transfer fins consisting of plate-like or pin-like projections. fuel reformer. 9. A fuel reformer according to any one of claims 1 to 7, characterized in that the gas flow path is filled with metal or ceramic particles.