JPH0530497B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention has a double pipe structure consisting of an outer pipe and an inner pipe, and an annular space formed between the outer pipe and the inner pipe is The present invention relates to a reaction apparatus comprising a reaction tube having a catalyst bed filled with a catalyst and in which the gas flow in the outer tube and the gas flow in the inner tube communicate at one end.

[Conventional technology]

An example of the prior art is disclosed in Japanese Unexamined Patent Publication No. 124534/1983, and its outline is shown in FIG. In the figure, 1 is a reaction tube, 2 is an outer tube,
An end cap 4 is connected to one end. 5
6 is an introduction pipe that introduces raw material gas into the outer tube 2, and 6 is an inner tube arranged concentrically with the outer tube 2 in the outer tube 2, and the gas flow in the inner tube 6 and the gas in the outer tube 2 are It communicates with the flow at one end. That is, they communicate through four end caps. 7 is a catalyst layer formed by filling the annular space formed between the outer tube 2 and the inner tube 6 with the catalyst 3; 8 is a receiving plate that supports the catalyst 3; 9 is the other end of the inner tube 6 A lead-out pipe that is connected to the inner pipe 6 and leads the reaction gas flowing inside the inner pipe 6 to the outside of the reaction tube 1;
These 2 to 9 constitute a reaction tube 1 having a double tube structure.

Next, the operation will be explained. For convenience of explanation, a steam reforming reaction apparatus will be explained as an example. Hydrocarbons and steam, which are raw material gases, are preheated to about 450°C, for example, and then introduced into the outer tube 2 through the introduction tube 5, and are then introduced into the catalyst layer 7 formed between the outer tube 2 and the inner tube 6. contact with the catalyst 3 of. Here, the raw material gas undergoes a steam reforming reaction and becomes a mixed gas (reformed gas) of H ₂ , CO, CO ₂ and the like. The steam reforming reaction is an endothermic reaction, and in order to compensate for this amount of heat, the outside of the outer tube 2 is heated by combustion gas. Further, in the steam reforming reaction, the hydrogen gas component increases as the temperature increases, so in a typical hydrogen production plant, the reformed gas temperature (reaction temperature) at the outlet of the catalyst bed 7 is set at, for example, about 800°C. Combustion gas heating is also used to increase this reformed gas temperature. After the reaction, the high-temperature reformed gas passes through a plurality of small holes (not shown) in the receiving tray 8, reverses its flow at the end cap 4, passes through the inner tube 6, and exits at the outlet tube 9 while remaining at a high temperature.
From there, it is led out of the reaction tube 1, that is, out of the system.

[Problem that the invention seeks to solve]

The conventional reactor is configured as described above, and in order to improve the heat transfer coefficient between the reformed gas in the inner tube 6 and the wall of the inner tube 6, the inner tube 6 is made with a small diameter and the reformed gas is Increasing the flow rate reduces the heat transfer area,
Conversely, when the heat transfer area is increased, the flow rate of the reformed gas in the inner tube 6 is reduced, and the heat transfer coefficient is reduced. Therefore,
The reformed gas at about 800℃ in the 4th part of the end cap is
There was a problem in that it was discharged out of the system at a high temperature, resulting in thermal waste.

This invention was made to solve the above-mentioned problems, and it is an object of the present invention to provide a reaction apparatus that can eliminate thermal waste.

[Means for solving problems]

The reaction device according to the present invention includes a baffle member disposed within an inner tube, and a cylindrical porous structure surrounding the buffle member.

[Effect]

The reactor according to the present invention disturbs the flow of high-temperature gas passing through the inner tube using the baffle member and the porous structure, and also utilizes solid radiation to effectively transfer the sensible heat of the high-temperature gas between the inner tubes. It's something you can tell on the wall.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In Fig. 1, 1 is a reaction tube, 2 is an outer tube, and 3 is a reaction tube.
is the catalyst, 4 is the end cap, 6 is the inner tube,
It has a slightly larger diameter than the conventional one. 7 is a catalyst layer, 8 is a receiving tray, and a plurality of small diameters 8a are provided. Reference numeral 10 denotes a baffle member disposed within the inner tube 6, and is composed of, for example, a support shaft 11 and a plurality of discs 12 pivotally supported by the support shaft 11. Reference numeral 13 denotes a cylindrical porous structure disposed so as to surround the baffle member 10, and is composed of, for example, a wire mesh, a metal wire braid, a tangled body of metal fibers, or the like.

Next, the operation will be explained. Hydrocarbons and steam, which are raw material gases, are preheated to about 450°C, for example, and then introduced into the outer tube 2 from the introduction tube 5 as in the conventional case, and come into contact with the catalyst 3 in the catalyst layer 7, where they undergo steam reforming. produce a reaction. After the reaction, the high-temperature reformed gas passes through the plurality of small holes 8a in the receiving tray 8, reverses its flow at the end cap 4, passes through the inner pipe 6, and is discharged out of the system from the outlet pipe 9. . The flow path of the high temperature reformed gas is narrowed by the baffle member 10 to increase the flow rate. Subsequently, the flow velocity decreases in the area where the buffling member 10 is not present, and the temperature boundary layer near the inner wall of the inner tube 6 is also separated. This improves the convective heat transfer coefficient between the inner tube 6 and the reformed gas. On the other hand, when the reformed gas passes through the porous structure 13, the porous structure 13 has a large contact area with the reformed gas and has the effect of disturbing the flow of the reformed gas. Therefore, the porous structure 13 effectively receives the sensible heat of the reformed gas through convective heat transfer with the reformed gas. The porous structure 13 heated thereby gives heat to the inner tube 6 by collective radiation. In this way, the baffle member 10 and the porous structure 13 effectively transfer the sensible heat of the high-temperature reformed gas passing through the inner tube 6 to the raw material gas or reformed gas flowing through the catalyst layer 7 through the pipe wall of the inner tube 6. The reaction efficiency of the steam reforming reaction between the raw material gas and the catalyst 3 in the catalyst layer 7 can be improved.

Furthermore, as shown in FIG. 2, by providing the porous structure 13 with a gentle concave portion 13a between the buttful members 10 and directing it toward the center of the inner tube 6,
This has the effect of further strengthening the boundary layer separation effect of the reformed gas flow due to the narrowing/expansion effect of the reformed gas flow path by the baffle member 10.

Incidentally, in the above embodiment, a case was described in which the baffle member 10 consists of a support shaft 11 and a plurality of discs 12, but it is also possible to use only a plurality of discs 12 as the baffle member 10, and to replace the discs 12 with a porous structure 13. It is also conceivable to maintain a fixed state between. Further, the disk 12 may be provided with a plurality of small holes.

Incidentally, in the above explanation, the case of a steam reforming reaction apparatus has been described, but the present invention is not limited to this and can be applied to other reaction apparatuses, and the same effects as those of the above embodiments can be achieved.

〔Effect of the invention〕

As explained above, this invention includes a buttful member disposed within an inner tube, a cylindrical porous structure surrounding the buttful member, and the sensible heat of the high-temperature gas passing through the inner tube transferred to the buttful member. The sensible heat of the high temperature gas is transferred to the gas in the catalyst layer through the wall of the inner tube, making effective use of the sensible heat of the high temperature gas. This has the effect of improving the reaction efficiency within the catalyst layer and eliminating thermal waste.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a main part showing a reactor according to one embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view of a main part showing a reactor according to another embodiment of the invention, and FIG. FIG. 2 is a longitudinal cross-sectional view showing the device. In the figure, 1 is a reaction tube, 2 is an outer tube, 3 is a catalyst, 6 is an inner tube, 7 is a catalyst layer, 10 is a baffle member, and 13 is a porous structure. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. It has a double tube structure consisting of an outer tube and an inner tube, and has a catalyst layer filled with a catalyst in an annular space formed between the outer tube and the inner tube. , a reaction apparatus comprising a reaction tube in which the gas flow in the outer tube and the gas flow in the inner tube communicate with each other at one end thereof, and a buttful member disposed in the inner tube, and a baffle member surrounding the buttful member. 1. A reaction device comprising: a cylindrical porous structure arranged in the following manner. 2. The reaction device according to claim 1, wherein the porous structure is composed of a wire mesh. 3. The reaction device according to claim 1, wherein the porous structure is a metal wire braided body. 4. The reaction device according to claim 1, wherein the porous structure is an entangled body of metal fibers. 5. The reaction device according to any one of claims 1 to 4, wherein the porous structure has a concave portion that is gentle toward the center of the inner tube between the buttful members.