JPH02160035A - Catalyst reaction apparatus - Google Patents

Abstract

PURPOSE:To improve heat exchange efficiency and to suppress the pressure drop of a reaction fluid side and/or combustion gas side as far as possible so as to reduce required driving power for press feeding by providing a heat recovering means which projects from the inside surface on the inside surface of an inner cylindrical pipe. CONSTITUTION:The other end of the outer cylindrical pipe 9 of the concentrical double cylindrical pipe-shaped reaction apparatus 1 having an inlet 5 and outlet 23 for reaction fluid on the same one end is closed and the other end side, except a part of one end side is projected into a heating chamber. The reaction fluid is passed from the inlet 5 through the annular space which is delineated and formed of the outer cylindrical pipe 9 and the inner cylindrical pipe 11 and is packed with a catalyst; thereafter, the fluid is turned over at the other end and is then passed through the inside space of the inner cylindrical pipe 11 so as to be introduced to the outlet 23. The gas which is a heating source is passed on the outside of the outer cylindrical pipe 9 from the other end side to the one end side. Further, the heat recovering means 19 which projects from the inside surface is provided on the inside surface of the inner cylindrical pipe 11. The heat recovering efficiency is improved with this apparatus by using this apparatus for the endothermic reaction, such as steam reforming reaction of hydrocarbon.

Description

[Detailed description of the invention] [Industrial application field] TECHNICAL FIELD This invention relates to a catalytic reaction device.

More specifically, the present invention relates to an apparatus with high heat recovery efficiency and low energy consumption suitable for use in endothermic reactions such as hydrocarbon steam reforming reactions.

[Prior Art] In a reaction device for steam reforming, etc. of a hydrogen generator, which has a catalyst inside and allows a reaction to occur at high temperature while receiving heat from the outside, heat exchange is used. In order to achieve efficient reaction and downsizing the equipment, a concentric double tube is used as the reaction tube.The annular space divided by the inner and outer tube walls is filled with catalyst, and the inside of the inner tube is heated to a high temperature. A method has been proposed in which the reacted gas is allowed to pass through. By adopting a double tube, the reacted gas that has passed through the catalyst layer in the high temperature range passes through the inner tube, and the sensible heat of the reacted gas is transferred to the catalyst layer through the inner tube wall. In addition, since the temperature of the reacted gas at the outlet of the steam reformer has decreased, it is possible to reduce the capacity of the heat recovery equipment, which consists of a group of heat exchangers installed downstream, and This is because the amount of heat dissipated is small because the temperature is low.

As a reactor in which the heat utilization efficiency of such a double-tubular reactor is further improved, for example, Japanese Patent Application Laid-Open No. 59-16536
In this case, a radiant face body is inserted inside the inner tube of the double tube, and the reacted gas that reverses at the outlet of the catalyst layer and rises inside the inner tube passes through the space inside the inner tube where the radiant face body is located. Sensible heat is transferred to the catalyst layer through the inner tube wall not only by convective heat transfer but also by radiation transfer from the radiant surface heated by convective heat transfer.

[Problems with the Prior Art] In devices that utilize a radiant surface as described above, sufficient heat exchange may not always be expected.

Regarding the heating side, when the reaction apparatus is installed in a heating furnace, which is a typical heating tank, heat transfer within the heating furnace is mainly performed by radiation of high-temperature combustion gas. After this heat transfer, the combustion exhaust gas, whose temperature has dropped to a temperature not high enough to expect heat transfer from the gas by radiant heat, is led to the combustion exhaust gas passage of the heating furnace, and is then exchanged with a heat exchanger using, for example, a bundle of bent tubes. By installing a container in the passage,
It was collecting the sensible heat it possessed. In this case, for example, it is conceivable to pass the raw material gas through the heat exchanger to preheat it and then send it to the reactor, but this inevitably makes the piping to be installed complicated. Furthermore, guiding the still hot gas out of the furnace increases the degree of heat dissipation and significantly reduces the efficiency of the entire apparatus.

The present invention avoids the above-mentioned problems, improves the efficiency of heat exchange with a simpler configuration, and further reduces the pressure loss on the reaction fluid side and/or the combustion gas side as much as possible, thereby reducing the required pumping power. The purpose is to provide a means to reduce

[Means for Solving the Problems] In the present invention, as a heat recovery means for effectively recovering the sensible heat of the reacted gas and/or the combustion exhaust gas, the heat transfer wall is integrally joined to the corresponding heat transfer wall. The heat recovery system is constructed using heat recovery means that enhances convective heat transfer, such as fins and protrusions that protrude from the walls.

That is, the present invention is: [a concentric double cylindrical tubular reactor having an inlet and an outlet for a reaction fluid at the same end, the other end of the outer cylindrical tube is open, and the double tube has a portion other than a part of the one end. The other end protrudes into the heating tank, and the reaction fluid is passed from the inlet through an annular space defined by an outer cylindrical pipe and an inner cylindrical pipe and filled with a catalyst, and then reversed at the other end. , then passed through the interior space of the inner cylindrical tube and guided to the outlet;
A reaction device characterized by: having a structure in which gas serving as a heating source is allowed to flow through the outside of the outer cylindrical tube from the other end to the one end, and a heat recovery means protruding from the inner surface is provided on the inner surface of the inner cylindrical tube. It is.

[Description based on the drawings] Examples of the present invention will be described in detail below using the drawings.

FIG. 1 is a longitudinal sectional view showing the reaction apparatus of the present invention installed in a heating furnace.

The catalytic reaction device 1 is fixed to the upper wall (ceiling) 3 of the furnace. In this example, in the presence of an appropriate catalyst, hydrocarbons capable of steam reforming reaction and steam are supplied as raw materials in a mixed state, and the catalyst layer is heated while receiving heat from the heating furnace. is mainly converted into hydrogen and carbon dioxide.

The raw gas mixture flows from the inlet 5 to the internal space 7 of the upper cap.
The liquid is then supplied to an annular space 13 defined by an outer cylindrical tube and an inner cylindrical tube 11.

This annular space is filled with a reforming catalyst 15 (the middle part other than the upper and lower parts is omitted in the diagram).The upper part of this catalyst layer mainly functions for preheating the raw material gas, and the lower part functions as a reaction.

After passing through this catalyst layer and being reformed, the raw material gas reaches the bottom 17 of the reaction tube, where it is turned over as a reacted gas and flows upward inside the inner cylindrical tube. A plate-shaped fin 19 parallel to the flow path is installed on the inner surface of the inner cylindrical tube, metallurgically joined to the tube wall and parallel to the flow path, corresponding to the portion functioning as the preheating unit described above. In order to metallurgically join metal plate-shaped fins with good thermal conductivity,
Welding and brazing are suitable. Metallurgical integral bonding is of course adopted because it has superior heat transfer compared to bonding by mere contact. In order to minimize pressure loss and expand the heat transfer area of the fins, for example, a thin plate made of stainless steel is bent into a wave shape and integrally joined to the inner surface of the inner tube by brazing or welding, and it is also made of the same material as the fins. Moyoi auxiliary cylinder (du-■y
5hell) 21 by brazing can be adopted. In this case, since the plate is thin, vacuum brazing is suitable. The method using such plate fins having thin wavy fins is suitable for the present invention, which aims to reduce pressure loss and improve heat exchange efficiency.

One end, preferably the upper end, of the auxiliary cylinder 21 is beveled to allow the reacted gas to flow only through the plate fins.

At the preheating site, the reacted gas supplies its sensible heat to the raw material gas flowing downward into the outer catalyst bed through the inner cylindrical tube wall via the aforementioned pretofin, and its own temperature decreases. Then, it is discharged from the outlet 23 of the reactor.

The discharged reacted gas is sent to the next process to be used for a desired purpose, such as a hydrogen electrode in a fuel cell, for example.
Depending on the purpose of use, the purity of hydrogen can be increased using a normal carbon oxide shift converter or a pressure swing adsorption device. In addition, 2
5 is an opening for filling the inside of the reactor with a catalyst.

In the example shown in Fig. 1, in order to effectively utilize the radiant heat of the combustion gas, an air-permeable ceramic wall 27 is placed around the longitudinal half of the reaction tube to partition the furnace space into upper and lower sections. It is located in

29 is a support for the ceramic plate provided on the outer tube.

In the lower part, that is, the radiant heat transfer space, heat transfer to the reaction tube is mainly performed by radiant heat from the combustion gas. For this reason, it is not advisable to place plate fins in this area; after radiant heat transfer, the combustion gases pass through this breathable ceramic and impart their sensible heat to it, so that the heat is transferred to the ceramic The radiation is returned to the bottom side and ultimately contributes to the heating of the reaction tube that protrudes downward from the vented wall.

Note that the material for the breathable wall may be any material that is heat resistant and breathable, and that can effectively return heat to the radiation heat transfer space with little pressure loss as described above. Therefore, for example, in addition to ceramic, it may also be at least partially made of a metal material.

The temperature of the combustion gas after passing through the permeable wall has fallen to an insufficient degree for heat transfer by radiation, but it still has sufficient sensible heat, so the heat of this gas is transferred to the raw material gas. In order to effectively use it for preheating, heat recovery means using convection heat transfer,
That is, as described above, typically, a heat transfer body, which is a plate fin 31, is integrally joined metallurgically to the outer surface of the reaction tube. Note that the outer circumferential tube of the plate fin 31 does not need to contribute to heat transfer, so it may be provided by simply seaming.

The part of the heating tank above the breathable material is called the convection heat transfer space, as opposed to the radiation heat transfer space.

The ratio of the vertical thicknesses of both heat transfer spaces is adjusted mainly by the temperature of the heating source gas.

The heating source gas can be used in the general case where the radiant heat transfer space of the heating tank is used as a combustion furnace, or by using combustion outside the heating tank. Gas heated by a heat source may be introduced into the radiant heat transfer space and air permeable. It can also be made to flow through a convection heat transfer space through a wall.

33 is a combustion exhaust gas outlet. In addition, 35 is a heat insulating material, 3
Reference numeral 7 indicates a steel mold for support, 3 indicates a double pipe inner partition tube, and 41 indicates a lower wall (floor) of the furnace.

The partition tube 39 is for preventing the catalyst filled in the annular space from entering the inner tube. In this example, the partition tube 39 is fixed to the outer tube bottom 17, and is concentric with the inner tube and axially mutually connected to the inner or outer surface of the inner tube. Border movable. The partition tube is provided with a number of holes between the lower end of the inner tube and the bottom of the outer tube to allow the reacted gas to pass from the annular space into the inner tube. Since the partition tube is fixed to the outer tube, mutual displacement due to differences in thermal expansion between the inner and outer tubes can be easily absorbed.

By arranging plate fins on both the inner surface of the inner cylindrical tube and the outer surface of the outer cylindrical tube of the reaction tube as shown in Figure 1, the sensible heat of the reacted gas and combustion gas can be effectively recovered and used. be able to. In this invention, as described above, plate fins are arranged on both the inner surface of the inner cylindrical tube and the outer surface of the outer cylindrical tube of the reaction tube, but in consideration of thermal calculation advantages and structural possibilities. , if necessary, may be provided on part or all of the inner and outer surfaces of the inner cylindrical tube and/or the outer cylindrical tube of the reaction tube.

[Effects] According to the present invention described in detail above, in the catalytic reaction device provided in the heating tank, heat recovery means, particularly a corrugated plate fin heat exchanger etc. effective for increasing the heat transfer area, etc. Since the heat transfer means is provided in necessary parts of the inner tube and/or outer tube of the cylindrical double tube of the catalytic reaction device, the sensible heat of the reacted gas and the combustion gas can be sufficiently used for preheating the raw material gas. Therefore, the heat recovery efficiency is improved, and the heat exchange efficiency of the entire heating furnace is improved, and the reactor can be downsized. Furthermore, since the pressure loss on the reaction fluid and/or combustion gas side is also small, the required pumping power on the reaction fluid side and/or the combustion gas side can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view illustrating a specific example of the present invention. 11 Inner cylindrical pipe, 5 Raw material gas inlet, 9 Outer cylindrical pipe, 15 Reforming catalyst, 1 fin, 23 Reaction gas outlet, 27 Breathable ceramic material 2

Claims (1)

[Claims] 1) A concentric double cylindrical tubular reactor having an inlet and an outlet for the reaction fluid at the same end, the other end of the outer cylindrical tube is closed, and the double tube is a part of one end. The other end protrudes into the heating tank, and the reaction fluid is passed from the inlet through an annular space defined by an outer cylindrical pipe and an inner cylindrical pipe and filled with a catalyst, and then reversed at the other end. , then passed through the inner space of the inner cylindrical tube and guided to the outlet, and the gas serving as a heating source is made to flow outside the outer cylindrical tube from the other end to the one end, and the inner cylindrical tube is A catalytic reaction device characterized by providing an inner surface with a heat recovery means protruding from the inner surface. 2) The outlet of the heating source gas from the heating tank is formed in an annular shape concentric with the double pipe between the outer pipe outer wall near the one end of the double pipe and the heating tank wall of the part from which the double pipe protrudes, that is, one end side wall. 2. The apparatus of claim 1, wherein the apparatus is a space. 3) The apparatus according to claim 1 or 2, further comprising heat recovery means projecting from the outer surface of the outer cylindrical tube. 4) The apparatus according to claim 1, wherein a heat recovery means is provided at a location corresponding to the outlet of the heating source gas. 5) The apparatus according to claim 3, wherein heat recovery means is provided at a location corresponding to the outlet of the heating source gas. 6) The apparatus according to any one of claims 1 to 5, wherein the heat recovery means is a plate fin providing a flow path parallel to the axial direction of the cylindrical tube. 7) By making the other end of the double pipe protrude to the side opposite to the one end side wall side, the space inside the heating tank is divided into a radiation heat transfer space on the other end side of the double pipe pipe and a convection heat transfer space on the one end side wall side. 7. The apparatus according to claim 1, wherein the apparatus is divided into a space.