JPH0222697B2 - - 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 reactor equipped with 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 with each other at one end.

[Prior art]

A conventional device is disclosed in, for example, Japanese Patent Application Laid-open 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. 10 is a heat insulating material attached to the outer peripheral surface of the end cap 4.

Further, FIG. 3 shows a state in which the reaction tube 1 is installed in a heating furnace, and in the figure, 11 is a heating furnace, 12 is a burner, and 13 is a combustion gas exhaust pipe.

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 , etc. 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 from the outlet tube 9 to the reaction tube. 1, that is, out of the system. Heating to compensate for the endothermic reaction is performed by burning fuel in the burner 12 and filling the heating furnace 11 with combustion gas. As mentioned above, since heating is also used to achieve the reaction temperature, a counterflow type is adopted for the raw material gas and the combustion gas. At this time, the high temperature flame generated by the burner 12 overheats the end cap 4, so
A heat insulating material 10 is attached to the outer peripheral surface of the end cap 4.

[Problem that the invention seeks to solve]

The conventional reactor is constructed as described above, and the flame from the burner 12, which has a higher temperature than the combustion gas filling the heating furnace 11, faces the end cap 4, and is protected from the flame. Because the view factor in radiant heat transfer to the end cap 4 is larger than the view factor in radiant heat transfer from the combustion gas to the outer tube 2, the temperature of the end cap 4 is higher than that of the outer tube even if the heat insulating material 10 is provided. There was a problem that the life of the heat-resistant steel was shorter than that of the outer tube 2.

This invention was made to solve the above-mentioned problems, and aims to provide a reactor with a long life.

[Means for solving problems]

The reactor according to the present invention has an end cap filled with heat transfer promoting particles.

[Effect]

The reactor according to the present invention aims to improve the heat transfer coefficient of the gas in the end cap by using heat transfer accelerating particles, thereby lowering the temperature of the end cap portion.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, numerals 1 to 10 have the same structure as the conventional device described above. 14 is end cap 4
These are heat transfer promoting particles made of, for example, a ball-shaped ceramic material, which are filled in the end cap 4 and are intended to improve the gas heat transfer coefficient within the end cap 4.

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 a plurality of small holes (not shown) in the receiving tray 8, reverses its flow at the end cap 4, and flows into the inner tube 6.
It is discharged to the outside of the system through the outlet pipe 9. Here, the end cap 4 is filled with heat transfer promoting particles 14, and by increasing the flow rate of the reformed gas, the heat transfer coefficient between the reformed gas and the end cap 4, that is, the gas side heat transfer coefficient increases. As a result, the radiant heat transferred from the flame generated by the burner 12 is effectively absorbed by the reformed gas in the end cap 4, and the temperature of the end cap 4 decreases in response to the amount of heat absorbed by this reformed gas. do. In the case of a high-temperature reaction such as a steam reforming reaction, it is necessary to use heat-resistant steel for the end cap 4 as well as the outer tube 2, but the creep life of the material increases significantly as the temperature decreases.

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.

Incidentally, in the above embodiment, a case has been described in which the heat transfer promoting particles are made of a ceramic material, but the heat transfer promoting particles may be made of other materials and the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As explained above, this invention can improve the gas heat transfer coefficient in the end cap by filling the end cap with heat transfer promoting particles, and can accordingly reduce the temperature of the end cap part. A reactor with a long life can be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a reaction apparatus according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing a conventional reaction apparatus, and FIG. 3 shows a state in which the conventional reaction apparatus is installed in a heating furnace. FIG. In the figure, 1 is a reaction tube, 2 is an outer tube, 3 is a catalyst, 4 is an end cap, 6 is an inner tube, 7 is a catalyst layer, and 14 is a heat transfer promoting particle. 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. In a reactor equipped with a reaction tube, the gas flow in the outer tube and the gas flow in the inner tube communicate with each other by an end cap fixed to one end of the outer tube. A reaction device characterized by being filled with heat transfer promoting particles. 2. The reactor according to claim 1, wherein the heat transfer promoting particles are made of ceramic material.