JPS6227033A - Reaction device - Google Patents

Abstract

PURPOSE:To improve the reaction efficiency in a catalyst layer by disposing approximately semi-circular or doughnut-shaped heat transmission accelerating members to the inside of an inside pipe constituting double pipes in the prescribed positional relation of plural points in the longitudinal direction thereof. CONSTITUTION:Hydrocarbon and steam are preheated to about 450 deg.C and are introduced from an introducing pipe into an outside pipe 2 so as to contact with a catalyst 2 in a catalyst layer 7 and to generate steam reforming reaction. The reforming gas of the high temp. with which the reaction ends passes through plural small holes 8a of a receiving tray 8 and is turned back by an end cap 4 so as to flow through the inside pipe 6 and to be discharged from a lead-out pipe to the outside of the system. The sensible heat of the high-temp. reforming gas is absorbed by the plural heat transmission accelerating members 10a, 10b, 10c in the process of lowing through the inside pipe 6. The absorbed sensible heat is transmitted through the wall of the inside pipe 6 to the gaseous raw material or reforming gas flowing in the layer 7.

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. 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]

As a conventional device, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. 58-124534, an outline of which is shown in FIG.

In the figure, (1) is a reaction tube, and (2) is an outer tube.

An end cap (4) is connected to one end.

(5) is an introduction pipe for introducing raw material gas into the outer pipe (2).

(6) is an inner pipe arranged in an intermittent circle with the outer pipe (2) within the outer pipe (2), and the gas flow in the inner pipe (6) and the gas flow in the outer pipe (2) are on one side. are connected at the ends. That is, they communicate through the end cap (4). (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), and (8) is the catalyst layer that supports the catalyst (3). The receiver is a dish, and (9) is an outlet pipe connected to the other end of the inner tube (6) to guide the reaction gas flowing inside the inner tube (6) to the outside of the reaction tube (1). 2) to (9) constitute a reaction tube (1) having a double tube structure.

Next, the operation will be explained. For convenience of explanation, two examples will be described using a Maruba steam reforming reactor. 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), and the outer tube (2)
contact with the catalyst (3) in the catalyst layer (7) formed between and the inner tube (6). here.

The raw material gas undergoes a steam reforming reaction, producing H, CO, and CO.

etc. becomes a mixed gas (reformed gas). The steam reforming reaction is an endothermic reaction, and in order to compensate for this amount of heat.

The combustion gas heats the outside of the outer tube (2). or.

In the steam reforming reaction, the higher the temperature, the more hydrogen gas components are present.
In a typical hydrogen production plant, the temperature of the reformed gas (reaction temperature) at the outlet of the catalyst layer (7) is set at about 2, for example, 800°C. Heating of combustion gas.

It is also used to increase the temperature of this reformed gas. After the reaction, the high-temperature reformed gas passes through multiple small holes (not shown) in the receiving pan (8), reverses its flow at the end cap (4), and flows through the inner tube (6). The outlet pipe (9) remains at high temperature.
to the outside of the reaction tube (1), i.e.

Extracted from the system.

[Problem that the invention seeks to solve]

A conventional reactor is configured as described above.

In order to improve the heat transfer coefficient between the reformed gas in the inner tube (6) and the tube wall of the inner tube (6), the inner tube (6) is made with a small diameter to increase the flow rate of the reformed gas and the heat transfer area is increased. Less.

Conversely, when the heat transfer area is increased, the flow rate of the reformed gas in the inner tube (6) decreases, and the heat transfer coefficient decreases. Therefore.

There was a problem in that the reformed gas at a temperature of about 800° C. at the end cap (4) was discharged out of the system while still at a high temperature, resulting in thermal waste.

This invention was made to solve the above-mentioned problems, and aims to provide a reaction apparatus that can eliminate thermal waste.

[Means for solving problems]

The reactor according to the present invention has a plurality of approximately semicircular or semi-doughnut shaped heat transfer promoting members arranged in a predetermined positional relationship in the longitudinal direction of the inner tube.

[Effect]

In this invention, the reactor absorbs the high-temperature gas sensible heat passing through the inner tube by the heat transfer promoting member, and the high-temperature gas sensible heat absorbed by the heat transfer promoting member passes through the wall of the inner tube and enters the catalyst layer. heat transfer to the gas.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figures to FIG. 3, (1) is a reaction tube.

(2) is the outer tube, (3) is the catalyst, and (4) is the end cap.

(6) has an inner tube with a slightly larger diameter than the conventional one. (7) is a catalyst layer, (8) is a tray,
A plurality of small holes (8a) are provided. Numerals (10) are heat transfer promoting members arranged in a predetermined positional relationship in the longitudinal direction of the inner tube (6), and are, for example, half-doughnut-shaped heat transfer promoting members. ) are heat transfer promoting members (10a l, (10b l).

As shown in (10c), the case is shown in which they are arranged in opposing positions that are reversed by 180 degrees. (11) is a heat transfer promoting member (10n L (10b), (10c)
A plurality of small holes are provided in each of the holes.

Next, the operation will be explained. Hydrocarbons and steam, which are raw material gases, are preheated to, for example, about 450°C, and then introduced into the outer tube (2) through the introduction tube (5) in the same way as in the past, and then heated to the catalyst (3) in the catalyst layer (7). ) in contact with.

Create a steam reforming reaction. The high-temperature reformed gas after the reaction passes through a plurality of small holes (8a) in the receiving pan (8),
Reverse the flow with the end cap (4).

It passes through the inner pipe (6) and is discharged to the outside of the system from the outlet pipe (9). The sensible heat of the high-temperature reformed gas is transferred to a plurality of heat transfer promoting members (10a), (10b), (
10c) and a plurality of heat transfer promoting members (I
on).

The sensible heat of the high temperature reformed gas absorbed by (10b) and (10c) passes through the wall of the inner tube (6) to the catalyst layer (
7) Heat is transferred to the raw material gas or reformed gas flowing inside. In this way, the sensible heat of the high temperature reformed gas passing through the inner pipe (6) is transferred to the plurality of heat transfer promoting members (10a), (10b),
The sensible heat of the high-temperature reformed gas is effectively absorbed by the inner tube (6
) can transfer heat to the raw material gas or reformed gas flowing in the catalyst layer (7) through the tube wall of the catalyst layer (7), which increases the reaction efficiency of the steam reforming reaction between the raw material gas and the catalyst (3) in the catalyst layer (7). Be able to improve.

Moreover, as shown in FIG. 2, a plurality of heat transfer promoting members (10a
), (10b), (10c) Boundary layer separation effect due to gas flow blown out from a plurality of small holes (11) provided in (10c).

Or heat transfer promoting members (10a), (10b),
(Inner tube for gas flow via the inward side of 10cl (
6) A further heat transfer promoting effect can be obtained due to the effect of destroying the boundary layer due to the reattachment of the gas flow to the inner wall.

In addition, by setting the porosity of the heat transfer promoting member (total area of the small holes in the heat transfer promoting member 8!/area of the heat transfer promoting member) to 5 to 60%, an effective effect can be obtained under appropriate conditions. be able to.

In the above embodiment, the heat transfer promoting member has a semi-doughnut shape, but as shown in FIG. 4, the heat transfer promoting member may have a substantially semi-doughnut shape.

Further, as shown in FIG. 5, the heat transfer promoting member may have a substantially semicircular shape, and other shapes similar to these shapes may also be used, and the same effects as in the above embodiment can be achieved.

Further, in the above embodiment, there are 18 heat transfer promoting members adjacent to each other.
Although we have described the case where they are placed in a positional relationship that is opposite to each other with 0 degrees reversed, it is also possible to arrange the heat transfer promoting members adjacent to each other in a spiral positional relationship by gradually shifting the angles of each other such as 45 degrees or 90 degrees. The same effect as the above embodiment can be expected.

Furthermore, in the above embodiments, the entire outer periphery of the heat transfer promoting member is in contact with the inner wall surface of the inner tube.

The outer periphery of the heat transfer promoting member is made uneven, that is, in the shape of a so-called gear, and the contact between the outer periphery of the heat transfer promoting member and the inner wall surface of the inner tube is to a degree that does not impede heat transfer efficiency. It is also possible to provide a space between the inner tube and the inner wall surface of the inner tube and utilize the flow of gas blown out from this space.

In the above embodiment, a case was described in which a plurality of small holes were provided in the heat transfer promoting member, but the intended purpose could be achieved even without providing a plurality of small holes in the heat transfer promoting member. .

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, in this invention, a plurality of heat transfer promoting members each having a substantially semicircular shape or a substantially semi-doughnut shape are arranged in a predetermined positional relationship in the longitudinal direction within the inner tube.

The sensible heat of the high temperature gas passing through the inner tube is absorbed by the heat transfer promoting member, and the sensible heat of the high temperature gas absorbed by the heat transfer promoting member is transferred to the gas in the catalyst layer through the wall of the inner tube. Therefore, the reaction efficiency within the catalyst layer can be improved by effectively utilizing the sensible heat of the high-temperature gas, which has the effect of eliminating thermal waste.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part showing a reaction apparatus according to an embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of a main part showing the arrangement of a heat transfer promoting member according to the present invention, and FIG. FIGS. 4 and 5 are cross-sectional views of main parts showing the shape of the heat transfer promoting member according to the present invention, and FIG. 6 is a cross-sectional view of main parts showing other embodiments of the heat transfer promoting member according to the present invention. FIG. 2 is a vertical cross-sectional view showing a conventional reaction apparatus. 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, and (io) is a heat transfer promoting member. Note that the same line numbers in the two figures indicate corresponding parts.

Claims (5)

[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, and the outer tube has a catalyst layer filled with a catalyst. In a reaction apparatus equipped with a reaction tube communicating at one end, a plurality of gas flows are arranged in a predetermined positional relationship in the longitudinal direction within the inner tube, and the gas flow in the inner tube is approximately semicircular. A reaction device comprising a heat transfer promoting member having a shape or a substantially semi-doughnut shape. (2) The reaction device according to claim 1, wherein the heat transfer promoting member is provided with a plurality of small holes. (3) The reaction device according to claim 1 or 2, wherein the heat transfer promoting members are positioned in such a manner that adjacent heat transfer promoting members are reversed by 180 degrees. (4) The reaction device according to claim 1 or 2, wherein the heat transfer promoting member is arranged spirally in the longitudinal direction. (5) The reaction device according to claim 2, wherein the heat transfer promoting member has a porosity of 5 to 60%.