JPH0124534B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an endothermic reactor for obtaining a reaction product gas from a feed gas by an endothermic reaction.

Endothermic reaction apparatuses that use catalysts that promote endothermic reactions to convert hydrocarbon-containing raw material gases into industrially useful gases such as hydrogen gas are well known in the art. For example, the most common technology for producing hydrogen gas from a feedstock gas is to place a cylindrical or annular reaction chamber filled with a catalyst in a combustion furnace, and a feedstock gas containing hydrocarbons is placed inside the reaction chamber. It is a process of steam reheating by passing through the water. In such an endothermic reaction apparatus, when heat is applied to the reaction chamber by the heating combustion gas, the heat is transferred from the outside of the reaction chamber. Therefore, in order to uniformly heat the surface of each reaction chamber with a high heat flux, it is necessary to form a relatively wide space around each reaction chamber. Furthermore, since it is necessary to uniformly arrange the relative positions of each reaction chamber and the furnace wall of the heating furnace, such an apparatus as a whole has to be a relatively large piece of equipment. Furthermore, in such a reactor, since heat transfer to the reaction chamber is mainly by radiation, the combustion gas of the heating furnace needs to be at a sufficiently high temperature even at its outlet. The heat energy taken outside is
Even if it is used as energy for steam production, its usefulness is lower compared to when it is used directly for the endothermic reaction of hydrogen generation, so overall the cost of generated hydrogen increases. It turns out.

For example, in fuel cell power generation equipment that uses hydrogen generated by reforming raw material gas containing hydrocarbons as fuel, in order to increase its economic efficiency, it is necessary to increase its thermal efficiency and reduce the cost of equipment and construction land. It is essential that Because of this need, a device that has a higher heat utilization rate, can be configured as a more compact device, and does not cause a decrease in reliability such as damage to the device due to uneven heating of the reaction chamber, etc. Steam rewarming equipment is requested.

Technologies proposed under this request include JP-A No. 53-78983, JP-A No. 53-78992, JP-A No. 53-79766,
Steam reforming devices described in various publications such as No. 53-79768 are known. In these devices, an annular reaction chamber is provided inside each reaction tube arranged in a heating furnace, and an annular regeneration chamber is provided inside this reaction chamber to transmit the sensible heat to the reaction chamber. , and a combustion gas exhaust passage is provided in the lower half of the combustion chamber provided as a gap around each reaction chamber, and this exhaust passage discharges combustion gas in a flow opposite to the flow of raw material gas in the reaction chamber. This is a technique configured to lead out in contact with the outer wall of the reaction chamber. Therefore, it can be said that such a device is a technology that satisfies the above-mentioned requirements to some extent.

However, it has been found that even such a device cannot fully satisfy the above requirements and there are problems that need to be solved.

That is, in the above-mentioned reaction apparatus, the upper space of each reaction tube serves as a combustion chamber, and a large number of burners are arranged here. Therefore, in this device,
The structure of the combustion chamber including the burner has to be complicated, which leads to an increase in the manufacturing cost of the device and has disadvantages in that maintenance is not easy. Furthermore, in order to achieve uniform heating of each reaction tube in such an apparatus, it is necessary to consider the arrangement of each burner, and this is not a problem that can be easily solved.

Therefore, in order to solve the above-mentioned production cost and maintenance issues, it is conceivable to use, for example, a single burner. In order to obtain as uniform heating as possible, it is conceivable to place this burner in the central part of the furnace. However, in such a burner arrangement, if the conventional reaction tubes are arranged at equal heights, it becomes substantially difficult to achieve uniform heating. This causes a problem that high heat transfer efficiency cannot be achieved.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to enable uniform heating to all the reaction tubes in the reactor, thereby achieving high transmission efficiency. The object of the present invention is to provide an endothermic reaction device that can realize thermal efficiency.

Specifically, even if only one ordinary gas burner is used, regardless of the position of the reaction tubes, that is, regardless of the distance from the burner, the flame from the burner will emit from each reaction tube. It is an object of the present invention to provide an endothermic reaction device capable of uniformly receiving radiation and uniformly transferring combustion gas radiant heat to a reaction chamber and a regeneration chamber.

The above object of the present invention is to provide a catalyst 40 which has an inlet for raw material gas _G1 on one end side and an outlet for reaction product gas _G2 on the other end side, and is used for an endothermic reaction.
a reaction chamber 20 filled with gas, and a regeneration chamber 30 that transfers the sensible heat to the reaction chamber 20 while extracting the reaction product gas G ₂ generated in the reaction chamber 20.
In an endothermic reaction apparatus 1 having a combustion chamber 11, a plurality of reaction tubes 21 are arranged in parallel in a reaction vessel 2, and each of the reaction tubes 21 is connected to the regeneration chamber 30 and the combustion chamber 11. The combustion chamber 11 is disposed in a space at one end of the reaction tube 21 with a burner 10 in the center thereof, and the upper end of the reaction tube 21 is located with respect to the burner 10. The lower end of the reaction tube 21 is arranged in a concave mirror shape that thermodynamically provides approximately uniform heating, and the lower end of the reaction tube 21 is arranged in a concave mirror shape that is approximately the same as the arrangement formed by the upper end 22 of the reaction tube. This is achieved by an endothermic reaction device 1 characterized in that it is arranged.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

The reactor 1 illustrated in FIG. 1 is for producing hydrogen by steam reforming using hydrocarbons as raw materials. A plurality of reaction tubes 21 are arranged in parallel inside the reactor container 2 having a heat insulating layer 8 installed therein. The reaction tube 21 in this example consists of two tube bodies arranged concentrically and having different diameters, and has a so-called double tube structure. Since the tube structure itself is not the gist of the present invention, it is not limited thereto, and the content of the present invention is merely explained based on the reaction tube 21 having a double tube structure. The inner tubular part of the double tube is the regeneration chamber 30 and the outer annular part is the reaction chamber 20. A combustion chamber 11 is disposed in the upper end 22 space of the reaction tube 21.
A burner 10 is disposed in the upper center of the space forming the space. The burner 10 in this specific example is
Although a gas burner is used, the fuel for the burner is not limited to gas, and may be heavy oil or the like.

The upper end 22 of the reaction tube 21 is disposed toward the space forming the combustion chamber 11.
2 is arranged in a concave mirror shape (hereinafter referred to as a concave surface) so as to thermodynamically provide substantially uniform heating with respect to the burner 10. According to the research of the present inventors, the radius (R) of the concave surface is 0.5D~
It has been found that the best uniform heating in the device is achieved with 2.0D, preferably between 0.5D and 1.5D. Here, D indicates the inner diameter of the container 2 excluding the wall thickness and the heat insulating layer 8. Note that the above ranges do not indicate upper or lower limits, and even when the above ranges are exceeded, substantially uniform heating can be achieved.

Further, each of the reaction tubes 21 is arranged so that its lower end forms the same concave surface as the upper end of each of the reaction tubes, and in consideration of ease of repair of the tube body, ease of catalyst filling, etc. It is secured by a provided tubesheet structure. The tube plate 23 is a plate-shaped body in which a plurality of holes are provided at positions corresponding to the arrangement of the reaction tubes 21 and forms the same concave surface as the concave surface formed by the upper end 22 of the reaction tubes 21. After being inserted into the hole, it is fixed to the tube plate 23.
A steam reforming catalyst 4 is provided in the reaction chamber 20.
Filled with 0s. A catalyst outflow prevention plate 24 is provided at the upper end of the catalyst packed bed, that is, at the outlet of the reaction chamber 20. A raw material gas G ₁ containing hydrocarbons and steam introduced into the reactor 1 from the raw material gas inlet nozzle 3 enters each reaction chamber 20 through the raw material gas manifold 4, and is converted into hydrogen by the action of the catalyst 40. The generated gas G ₂ containing
0 exits into the upper space 25 inside the reaction tube 21 from the upper end. The upper end 22 of the reaction tube 21 is sealed so that the space 25 can be formed. The sealing portion 26 is covered with a heat-resistant cap 27. In this specific example, the material of the cap 27 is made of ceramic as a measure against high temperature heating of the combustion gas g sent from the combustion chamber 11, but the material is not particularly limited to this as long as it is made of a heat-resistant material.

Reaction product gas sent to reaction tube upper space 25
G ₂ passes through a regeneration chamber 30 having an inlet 28 in the head space 25 and reaches the product gas manifold 5;
The produced gas is taken out of the apparatus 1 through the outlet nozzle 6. Since this catalytic reaction is an endothermic reaction,
Heat must be supplied to the reaction chamber 20, and the heat sources are the heat supplied from the combustion gas g and the sensible heat from the regeneration chamber 30. The combustion gas g is generated in a burner 10 provided in the upper space of the upper end 22 of the reaction tube 21 and sent to the combustion chamber 11 located in the space, from the direction of the upper end 22 of the reaction tube 21 to the direction of the lower end of the reaction tube 21. The combustion gas flows through the passage 12 formed by the reaction tubes 21 and the passage 12' formed by the reaction tube 21 and the inner wall of the reaction vessel 2, and is taken out from the combustion gas outlet nozzle 7 to the outside of the apparatus 1. It will be done. Although the flow direction of the combustion gas g is opposite to the flow direction of the reaction gas in the reactor 20, the present invention is not particularly limited to this, and it is possible to carry out the present invention in a parallel flow system. It is possible.

The combustion gas passages 12, 12' are divided into upper and lower sections, and the lower section 13 is filled with a packing material 14 for improving heat transfer.
It is supported on a support member 15 located near the lower end of 12'. The packing material 14 in this specific example is an alumina ball. As mentioned above, the regeneration chamber 30 is the inner tubular part of the reaction tube 21 which has a double-tube structure, and although it can sufficiently function as the regeneration chamber 30 even in a hollow state inside this tube, the heat transfer performance In order to improve the heat transfer effect, it is also possible to provide means for improving the heat transfer effect, such as filling the regeneration chamber 30 with a heat transfer packing or providing fins on the tube.

In the above specific example, since the reaction tubes are arranged so that their upper ends are concave, even if one ordinary gas burner is used, each reaction tube can be It has become possible to evenly receive flame radiation from the burner, and also to receive evenly the radiant heat of the combustion gas that transfers heat to the reaction chamber and the regeneration chamber. In addition, due to the tube plate structure, the lower end of the reaction tube forms the same concave surface as the upper end of the reaction tube, that is, the length of the reaction tube is the same, so the manufacturing cost of the reaction tube is low. At the same time, it became possible to standardize refomers. This, together with the simplification of the structure of the combustion chamber having the burner described above, has made it possible to reduce the manufacturing cost of this device and to facilitate maintenance.

Furthermore, it is possible to employ a tube plate structure to fix the reaction tube, making operation and maintenance of the apparatus easier than with the reformers described in the above-mentioned publications, and making it possible to make the apparatus more compact.

In the above specific example, the reaction tube has a double tube structure, but the present invention is not limited to this. This applies to all reformers having a structure in which a combustion chamber is provided at one end of a tube having a reaction chamber and a regeneration chamber. For example, the above-mentioned Japanese Patent Application Publication Nos. 53-78983, 53-78992, and 53-79766.
The present invention is also applicable to the reformers described in various publications such as No. 1, No. 53-79768, and the reformers described in patent applications (A) and (B) filed on the same day as the present application.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing a specific example of an endothermic reaction device according to the present invention. FIG. 2 is a sectional view of the top of the reaction tube. 1... Reactor, 2... Reactor container, 3...
Raw material gas inlet nozzle, 4... Raw material gas manifold, 5... Produced gas manifold, 6... Produced gas outlet nozzle, 7... Combustion gas outlet nozzle, 8...
...Insulation layer, 10...Burner, 11...Combustion chamber,
12... Combustion gas passage, 12'... Combustion gas passage,
13... Lower compartment part, 14... Packing material,
15... Support member, 20... Reaction chamber, 21... Reaction tube, 22... Upper end of reaction tube, 23... Tube sheet, 2
4...Outflow prevention plate, 25...Space, 26...Sealing section, 27...Cap, 28...Regeneration chamber entrance, 3
0... Regeneration chamber, 40... Catalyst, G ₁ ... Raw material gas,
G ₂ ... reaction product gas, g ... combustion gas.

Claims (1)

[Claims] 1. A reaction chamber having an inlet for raw material gas at one end and an outlet for reaction product gas at the other end, and filled with a catalyst used for an endothermic reaction, and the reaction product gas generated in the reaction chamber. An endothermic reaction device having a combustion chamber and a regeneration chamber that transfers the sensible heat to the reaction chamber while deriving the heat, the reaction device having a plurality of reaction tubes arranged in parallel in a reaction vessel, Each of the reaction tubes has the regeneration chamber and the reaction chamber, and the combustion chamber is disposed in one end space of the reaction tube and includes a burner in the center thereof. The upper end of the reaction tube is arranged in a concave mirror shape to thermodynamically provide substantially uniform heating with respect to the burner, and the lower end of the reaction tube is arranged in the concave mirror shape formed by the upper end of the reaction tube. An endothermic reaction device characterized by being arranged in substantially the same concave mirror shape.