JP2600950B2 - Endothermic reactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an endothermic reaction apparatus for obtaining a reaction product gas from a raw material gas by an endothermic reaction, and particularly to the production of a hydrogen-rich gas by a reforming reaction which is an endothermic reaction. The present invention relates to a fuel reformer for a fuel cell power generator.

[Conventional technology]

The fuel cell power generation device, which has reached the stage of practical use, is expected to be used as a small-sized (power generation output of several tens to several hundreds of kW) on-site device by utilizing its features. An endothermic reactor used in a fuel reformer, which is a main component of such a fuel cell power generator, requires performance such as small size, light weight, low cost, and high efficiency. To respond to these,
The present applicant has previously proposed an endothermic reaction apparatus using a double cylindrical reaction tube as shown in FIG. In the figure, a reaction tube 2 is housed inside a furnace casing 23, and a burner 3 is provided inside the reaction tube 2. The reaction tube 2 is externally connected to an upright partitioning cylinder 4 and an inner tube 6 disposed concentrically inside and outside of the partitioning cylinder 4 with its lower end separated from the lower end of the partitioning cylinder 4 and connected by a semi-torus-shaped member 7. The tube 5 is formed. With such a structure, a double annular space of the outer annular space 8 and the inner annular space 9 communicating with the lower end portion is formed in the reaction tube 2.

A source gas inlet 11 is formed above the outer annular space 8 via a source gas manifold 10, and a reaction gas outlet 13 is formed above the inner annular space 9 via a reaction gas manifold 12.
Are formed.

Refractory insulation layers 14 and 15 are arranged below and around the reaction tube 2 at intervals, and a combustion gas passage 16 for guiding the fuel gas of the burner 3 is formed between the reaction tube 2 and the refractory heat insulating material layers 14 and 15. A combustion gas outlet 17 is formed in an upper portion of the combustion gas passage 16.

The burner 3 is located at a position slightly lower than the upper and lower center of the reaction tube 2. In the reaction tube 2, a reaction catalyst 18 as a reforming catalyst is provided in all of the outer annular space 8 except for the raw material gas manifold 10 portion and a portion (a) of the inner annular space 9 which receives the heat of the burner 3. Is filled. Heat transfer particles 19 are filled in a portion (b) above a portion of the inner annular space 9 from which the burner 3 does not receive heat. Further, the upper portion of the combustion gas passage 16 is filled with heat transfer particles 20 for promoting convective heat transfer from the combustion gas to the reaction catalyst.

In the above-described endothermic reaction apparatus, fuel (exhaust gas from the fuel cell main body during operation of the fuel cell) is supplied to the burner 3 from the fuel inlet 21, and is burned by the combustion air from the air inlet 22. The combustion gas from the burner 3 is supplied to the reaction tube 2
Flows through the combustion gas passage 16 from the inside to the outside along the reaction catalyst filling portion, and is discharged from the combustion gas outlet 17.

On the other hand, the raw material gas enters through the raw material gas inlet 11 and flows downward through the catalyst layer in the outer annular space 8. Then, it is inverted below the partition cylinder 4 and flows upward in the inner annular space 9.

The combustion gas of the burner 3 radiates heat during a high temperature, and heats the catalyst-filled portion of the reaction tube 2 by convection heat transfer when the temperature decreases, thereby applying heat to the raw material gas in the catalyst layer, Is reformed into a hydrogen-rich gas to generate a reformed gas. In the filling portion of the heat transfer particles 19 which no longer receives the heat from the burner 3, the reformed gas which is a reaction product gas transfers the heat to the heat transfer particles 19.
The temperature is lowered while supplying the raw material gas flowing through the outer annular space 8 through the outer ring space 8, and the gas leaves the reaction gas outlet 13.

[Problems to be solved by the invention]

In the above-mentioned endothermic reaction apparatus, the inner and outer annular spaces of the double cylindrical reaction tube are filled with the reaction catalyst, and heat transfer particles such as alumina holes are provided in the combustion gas passage outside the double cylindrical reaction for the purpose of increasing thermal efficiency. To promote the convection current. For this reason, the supply of heat required for the reforming reaction is mainly convection heat transfer, and it is difficult to obtain a high heat flux. Therefore, the heat transfer area is increased, that is, the reaction tube diameter is increased, or the reaction tube length is increased. Needed to be longer. For this reason, there is a problem that the amount of the reaction catalyst also increases, and as a result, the entire apparatus becomes large.

An object of the present invention is to provide a small-sized, lightweight, low-cost, high-efficiency endothermic reaction apparatus by supplying heat required for the reforming reaction mainly by radiant heat transfer and increasing the heat flux.

[Means for solving the problem]

According to the present invention, there is provided a reaction vessel having a concentric inner and outer double annular space via a burner and a partition cylinder, and a furnace vessel provided with a space between the reaction tube and the reaction vessel. Wherein the inner and outer annular spaces communicate with each other at the lower end of the partitioning cylinder, the upper end of the outer annular space has a raw material gas inlet, and only the inner annular space is filled with a reaction catalyst. The burner is located at the upper end inside the reaction tube, and the combustion gas passes through the space between the lower end of the reaction tube and the bottom of the furnace vessel. This is achieved by being guided along the outer wall of the space to the combustion gas outlet at the top of the furnace vessel.

[Action]

Only the inner annular space of the inner and outer double annular spaces of the reaction tube is filled with the reaction catalyst, and the reaction catalyst is mainly supplied with radiant heat from combustion by a burner disposed at the upper end inside the reaction tube. Therefore, a large heat flux can be obtained, and an endothermic reaction can be promoted. The outer annular space serves as a raw material gas passage, and the raw material flowing through the outer annular space by the combustion gas flowing through the combustion gas passage between the furnace vessel and the outside of the reactor and flowing into the inner annular space filled with the reaction catalyst. Raise the temperature of the gas.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a main part of an endothermic reaction apparatus according to an embodiment of the present invention. In FIG. 1, the same parts as those of the apparatus shown in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted.
The difference between FIG. 1 and FIG. 2 is that only the inner annular space 9 of the reaction tube 2 is filled with the reaction catalyst 18, the outer annular space 8 serves as a raw material gas passage, and the burner 3 is provided at the upper end inside the reaction tube 2.
It is that was arranged. In such a configuration, the flow of the combustion gas by the combustion in the burner 3 is the same as that in FIG.

On the other hand, the raw material gas enters through the raw material gas inlet 11, flows downward in the outer annular space 8, reverses below the partition cylinder 4, and flows upward in the reaction catalyst 18 in the inner annular space 9. Since only the inner space 9 inside the reaction catalyst 18 is filled by such a flow of the raw material gas, the supply of heat necessary for the reforming reaction is mainly performed by radiant heat transfer from the combustion gas burned by the burner 3. . As a result, the heat flux can be increased, the heat transfer area can be reduced, and the size and weight can be reduced.

Next, the volume, catalyst amount,
FIG. 3 shows the results of comparison of the heat flux and the like. As shown in FIG. 3, the heat flux according to the present invention is about three times as large as that shown in FIG. 2, so that the catalyst amount can be reduced to 1/4 and the volume can be reduced to 1/2.

By increasing the flow rate of the combustion gas by narrowing the gap of the combustion gas passage 16, heat transfer to the raw material gas flowing through the outer annular space 8 can be improved, and the temperature of the combustion exhaust gas can be reduced accordingly. Therefore, the heat efficiency does not decrease.

By the way, in the description of the above-described embodiment, the configuration of FIG. 1 in which the upper burner is disposed has been literally described. However, the entire apparatus of FIG. 1 is turned upside down, and the burner is disposed at the lower side. The same effect can be obtained even with the above configuration.

〔The invention's effect〕

As is clear from the above description, the reaction catalyst is filled only in the inner annular space of the reaction tube composed of the inner and outer double annular spaces,
By providing the burner at the upper end inside the reaction tube, heat is given to the reaction catalyst layer in the inner annular space mainly by radiant heat transfer from the combustion gas by combustion in the burner. The heat flux required for the endothermic reaction in the reaction catalyst layer in the inner annular space of the raw material gas heated from the combustion gas by the combustion gas from the upper part to the lower part can be increased by the radiant heat transfer of the combustion gas. And a heat transfer area can be reduced, so that a small, lightweight, low-cost and highly efficient endothermic reactor can be obtained.

[Brief description of the drawings]

FIG. 1 is a cutaway view of a main part of an endothermic reactor according to an embodiment of the present invention, FIG.
FIG. 3 is a diagram comparing the specifications of the conventional device and the device of the present invention. 1: furnace vessel, 2: reaction tube, 3: burner, 4: partition cylinder, 5: outer tube,
6: inner pipe, 8: outer annular space, 9: inner annular space, 11: raw material gas inlet, 13: reaction gas outlet, 16: combustion gas passage, 17: combustion gas outlet, 18: reaction catalyst.

Claims (1)

(57) [Claims] An endothermic reactor comprising a burner, a reaction tube having a concentric inner and outer double annular space via a partition cylinder, and a furnace vessel provided with a space between the reaction tube and the reactor tube. The inner and outer annular spaces communicate with each other at a lower end of the partition cylinder, and a raw material gas inlet is provided at an upper end of the outer annular space. Only the inner annular space is filled with a reaction catalyst and reacts at the upper end thereof. With a neutral gas outlet,
The burner is located at the upper end inside the reaction tube, and the combustion gas passes through the space between the lower end of the reaction tube and the bottom of the furnace vessel, and runs along the outer wall of the outer annular space to the combustion gas outlet at the top of the furnace vessel. An endothermic reactor characterized by the fact that: