JPH01215340A - Fuel reformer - Google Patents

Abstract

PURPOSE:To improve heat transmission and to make the title fuel reformer compact by providing a catalyst supporting material to press the reforming catalyst on the wall surface of a reaction tube in the reformer wherein the catalyst is held on the wall surface of the reaction tube. CONSTITUTION:The reforming catalyst 9 is held on the wall surface of the reaction tube 1 in the fuel reformer. The catalyst supporting material 10 (e.g., stainless steel wool) to press the catalyst 9 on the wall surface of the reaction tube 1 is provided. As a result, the catalyst can be stably held irrespective of a change in the operating condition and with the lapse of time, and the reliability is enhanced. In addition, since the catalyst supporting material has many points of contact with the catalyst, the flow of a fluid reactant is disturbed by the points of contact, hence the heat transmission can be improved, the heat efficiency is increased, and the reformer can be made compact.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel reformer, and particularly to a fuel reformer that is compact and suitable for use in fuel cell power generation devices and the like.

[Conventional technology]

A fuel reformer used in a fuel cell power generation device is 1. For example, as described in Japanese Patent Publication No. 57-7538, the reaction that flows through a cylindrical reforming catalyst bed filled in the gap of a double-tube reaction tube is used. By making the combustion gas and reformed gas flow in counter-flows to the gas flow direction, heating the reforming catalyst layer from the inside and outside, and filling the double-tube reaction tube with heat transfer particles so as to surround it from the outside. In addition to the structure that promotes heat transfer from combustion gas to reactant gas, there is a heat transfer plug inside the inner tube to increase the reformed gas flow rate and improve heat transfer, and on the outside of the outer tube to increase the combustion gas flow rate. , a structure including a heat transfer sleeve for improving heat transfer is known.

In addition, as described in Japanese Patent Application No. 61-60073, a reforming catalyst is held on the wall surface of the reaction tube, and the distance between the heated gas side that provides heat and the heated object side of the reforming catalyst that requires heat is A fuel reformer is being considered that aims to improve heat transfer performance by minimizing the length of time.

[Problem to be solved by the invention]

Since the reforming performance of the fuel reformer is heat transfer, the above conventional technology improves heat transfer and heat conduction by changing the flow state near the heat transfer surface and the holding state of the reforming catalyst. It's in the picture.

However, the provision of new structural members to change the flow conditions complicates the equipment and increases costs, so it is best to avoid this as much as possible. Reaction tube with heat cycle,
Furthermore, it is necessary to improve reliability so that the retained state can be maintained against differences in expansion and contraction of the catalyst, fluid flow, and the like.

The main object of the present invention is to provide a compact fuel reformer, and another object of the present invention is to provide a fuel reformer with high reliability that can maintain a catalyst retention state despite changes in operating conditions and the passage of time. Our goal is to provide reformers.

[Means to solve the problem]

The above object is achieved in a fuel reformer that holds a reforming catalyst on the wall surface of the reaction tube, by providing a catalyst support material that presses the reforming catalyst against the wall surface of the reaction tube.

[Effect]

The catalyst support material has many contact points with the reforming catalyst and has the function of pressing the reforming catalyst against the wall surface of the reaction tube. This prevents the reforming catalyst from peeling off or falling due to the difference in thermal expansion and contraction between the reforming catalyst and the reaction tube during the heat cycle, and maintains the state in which the reforming catalyst is retained on the wall surface of the reaction tube. Additionally, because the catalyst support material has multiple contact points with the reforming catalyst, the flow of the reactant fluid is disturbed near those contact points, improving heat transfer, which improves thermal efficiency and improves fuel reformer efficiency. can be made more compact.

(Example) Hereinafter, an example of the present invention will be explained with reference to Fig. 1.
The figure shows a fuel reformer consisting of a single-tube reaction tube. A flange 2 is provided at one end of the cylindrical reaction tube 1 of the fuel reformer, and a reaction gas 1 is disposed opposite to the flange 2.
A flange 4 having a conduit 3 leading to the flange 1 is joined by several bolts 5 and nuts 6 with a packing 7 in between.

A reforming catalyst 9 is deposited by thermal spraying on the inner wall surface of the reaction tube 1, which is provided with a conduit 8 serving as an outlet for the reformed gas 12 at the other end of the reaction tube 1 of the fuel reformer. The space surrounding the reforming catalyst 9 is filled with a catalyst support material 1o such as stainless wool.

Next, the operation of this embodiment will be explained. Taking as an example a mixed gas of methane and water vapor as the reaction gas 11 introduced into the fuel reformer, consider the case where a hydrogen-enriched gas is obtained as the reformed gas 12. in this case.

Since a relatively large endothermic reaction occurs in the reactor 1, the portion where the reforming catalyst 9 is held is heated from the outside of the reactor 1 with a heating medium 13, and the reaction tube 1 is heated to a temperature of about 800°C. maintain. The reaction gas 11, which is a mixed gas of methane and water vapor, is sent into the reaction tube 1 through the conduit 3, and undergoes a reforming reaction on the surface and inside of the reforming catalyst 9 attached to the inner wall surface of the reaction tube 1. and is transformed into hydrogen-enriched gas. At this time.

The reaction gas 11 is agitated as a whole due to the presence of the catalyst support material 10, and is also agitated near numerous contact points between the catalyst support material 10 and the reforming catalyst 9, thereby promoting the reforming reaction and heat transfer. . Further, the catalyst support material 10 acts to press the reforming catalyst 9 against the inner wall surface of the reaction tube 1 at a large number of contact points with the reforming catalyst 9.

In particular, under high temperatures during operation of a fuel reformer, the catalyst support material 1
0 thermally expands, presses the reforming catalyst 9 against the inner wall surface of the reaction tube 1, and maintains the state in which the reforming catalyst 9 is held.

The reforming reaction is carried out by the reforming catalyst 9 receiving heat from the outside of the reaction tube 1. The reaction gas 11 comes into contact with a predetermined reforming catalyst 9 and becomes a reformed gas 12, which is a hydrogen-enriched gas, and exits the reaction tube 1 through the conduit 8.

According to one embodiment of the present invention, in a fuel reformer in which a reforming catalyst is attached to the inner wall surface of a 9-reaction tube, a catalyst supporting material such as stainless wool is stuffed into the reaction tube to maintain the retention state of the reforming catalyst. Therefore, it is possible to reduce the amount of catalyst that is filled in the space inside the conventional reaction tube, which has the effect of reducing costs. In addition, by using a physically continuous catalyst support material, it is easier to handle when replacing it, and by using a material with higher thermal conductivity for the catalyst support material, the thermal efficiency of the fuel reformer is improved. Further improvements can be made.

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

FIG. 2 is a cross-sectional view of the main parts of the reaction tube 1 of the fuel reformer R when it is configured with a double-tube type reaction tube.

The reaction tube 1 itself constitutes an outer tube 1 and includes an inner tube 14 therein coaxially with the outer tube 1.

In this case, the reforming catalyst 9 is attached to the inner wall surface of the outer tube 1 and the outer wall surface of the inner tube 14 by thermal spraying, and the catalyst support material 10 is attached to the inner wall surface of the outer tube 1 and the outer wall surface of the inner tube 14.
and the inner tube 14.

The operation according to this embodiment will be explained. The reaction gas 11, which is a mixed gas of methane and water vapor, is supplied to the outer pipe 1 of the fuel reformer.
While flowing through the annular space formed between and the inner tube 14,
By contacting the reforming catalyst 9 attached to the inner wall surface of the outer tube 1 and the outer wall surface of the inner tube 14 and causing a reforming reaction, the reaction gas 11 is transformed into hydrogen-enriched gas. Due to the presence of the catalyst support material 10, the whole is agitated, and also in the vicinity of the numerous contact points between the catalyst support material 1o and the reforming catalyst 9, thereby promoting the reforming reaction and heat transfer.

Further, the catalyst support material 10 presses each of the reforming catalysts 9 attached to the inner wall surface of the outer tube 1 and the outer wall surface of the inner tube 14 to the respective wall surfaces. Approximately 75% of the heat required for the reforming reaction is supplied from the outside of the outer tube 1 by the heating medium 13, and the remaining approximately 25% of the heat is supplied to the reaction gas 11 by the reformed gas 12 passing through the inner tube 14. This is supplemented by heat exchange with The generated reformed gas 12 is guided to the outside of the fuel reformer via the inner pipe 14.

According to this embodiment, in a fuel reformer in which a reforming catalyst is attached to the wall surface of a reaction tube, a catalyst support material such as stainless wool is stuffed into an annular space formed by a double tube.
Since the holding state of the reforming catalyst can be maintained and the reaction liquid can be stirred, thermal efficiency can be improved and the amount of catalyst can be reduced. In addition, the catalyst support material such as stainless wool absorbs the thermal expansion of the outer and inner reaction tubes without compressing the catalyst particles as in the conventional case. Can be done.

〔Effect of the invention〕

According to the present invention, heat transfer performance is improved and the fuel reformer can be made more compact.

[Brief explanation of the drawing]

1 and 2 are partial cross-sectional views of one embodiment of the present invention. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A fuel reformer in which a reforming catalyst is held on a wall surface of a reaction tube, characterized in that a catalyst support material for pressing the reforming catalyst against the wall surface of the reaction tube is provided. A pawn.