JPS6183602A - Reforming apparatus - Google Patents

Abstract

PURPOSE:To prevent the sink of the reforming catalyst layer after the use for a long period, to follow the thermal expansion of the reforming tube caused by temperature variation, and to carry out the reforming of a gas in an extremely high efficiency, by using a specific reforming tube in a gas reforming apparatus. CONSTITUTION:A short inner tube 21 of the upper catalyst layer is integrated with the upper grating 17 in the reforming tube 6, and the upper grating is fixed with the plural protrusions 22 attached to the inner wall of the end plate 12. A long inner tube 23 of the lower catalyst layer is integrated with the lower grating 18, and is inserted into the inner tube 21 of the upper catalyst layer in a vertical movable manner. The inner tube 23 of the lower catalyst layer is connected and fixed to the center plug 9 and the reformed gas outlet pipe 26 through the bottom plate 24, and a constricted coil spring 28 is inserted between the inner tube 23 and the partition plate 25 placed below the tube and acting the role of a fixing bed. Accordingly, the lower grating 18 and the inner tube 23 of the lower catalyst layer are constantly pushed up with the coil spring 28, to enable the efficient reforming following the thermal expansion of the reforming tube 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to improvements in general gas reformers or gas-to-gas heat exchangers.

[Technical background of the invention and its problems 1 The structure of a commonly used gas reformer will be explained with reference to FIG. 3. In the figure, a gas reformer 1 sends combustion gas and combustion air to a burner 2 and burns them in a combustion v3, and the heated fluid generated by the combustion passes through a heating flow path 4 and is discharged to the outside from an exhaust gas outlet 5. This combustion heat heats the plurality of reforming tubes 6 provided inside the reformer 1.

On the other hand, inside the reforming tube, a reformed gas flow path is provided completely isolated from the combustion gas heating flow path 4. The reformed gas flowing from the reformed gas lower part flows inside the catalyst layer 8 provided on the inner wall of the reforming tube 6 and supported by the other perforated plate (hereinafter referred to as lower perforated plate) 18, and rises. The reformed gas changes direction at the upper end, flows through a return bus 10 formed between the catalyst N8 and the center plug 9, and flows out from the reformed gas outlet 11. During this time, the reformed gas, such as methane and steam, is reformed into hydrogen and carbon dioxide gas. Although there may be only one reforming pipe 6 inside the reformer 1, generally a plurality of reforming pipes 6 are provided as shown in FIG.

FIG. 4 is a detailed cross-sectional view showing an enlarged portion of the catalyst layer 8 on the combustion side, which is outlined in FIG. 3. In the figure, the reforming tube 6 is made by welding an end plate 12 and a welding line 13. As already explained in FIG. 3, the upper part of the reforming tube 6 near the combustion chamber 3 becomes high in temperature, so a cap 14 made of a heat insulating material is placed over the end plate 12. Furthermore, since defects are likely to occur in the weld line 13, a temperature measuring element 15 is provided at this portion to measure the temperature.

The reformed gas rises in the catalyst layer 8, passes through the upper end 16 of the catalyst layer, reverses itself at the upper end of one perforated plate (hereinafter referred to as upper perforated plate) 17, and passes through the return bus 10 formed by the plug guide 19. It descends and flows out.

The upper perforated plate 17 is a perforated plate made of a heat insulating material.

This upper perforated plate 17 is originally provided to prevent catalyst particles from floating at the upper end 16 of the catalyst layer, but in reality, the upper perforated plate 17 and the upper end 16 of the catalyst layer are A gap of size 1 is created between them.

That is, the first reason is that the reforming tube 6 generally expands due to thermal expansion during the reforming reaction, but the thermal expansion coefficient of the reaction catalyst is smaller than that of the reforming tube 6. The second reason is that although the catalyst layer 8 is supported by the lower perforated plate 18 (FIG. 3), not only the inner diameter of the reforming tube 6 expands due to heat, but also the outer diameter of the catalyst layer inner tube 20 expands due to heat. Since the diameter also expands,
The upper end 16 of the catalyst layer is lowered by an amount corresponding to the increase in volume during this period. In addition, when filling the catalyst particles, the reforming tube 6 is turned upside down and filled while vibrating the tube. The upper end 16 sinks to form the upper perforated plate 1.
7, a space of dimension 1 is created between the two. In such a state, the weld line 13 of the reforming tube 6 will come out above the upper end 16 of the catalyst layer, and as a result, a large difference will appear between the temperature of the weld line 13 and the temperature of the catalyst layer 8. Become. For this reason, the reforming operation is performed while monitoring the temperature of the weld line 13 with the temperature measuring element 15, but if a space is created, the temperature at the upper end 16 of the catalyst layer will not increase and the reforming efficiency will deteriorate. .

To explain the above relationship in more detail, when the inside of the reforming tube 6 is filled only with the flow of reformed gas, compared to the case where the inside of the reforming tube 6 is filled with a catalyst, the inside of the reforming tube 6 is Since the heat transfer coefficient to the reformed gas becomes extremely poor, if there is no catalyst inside the welded part of the reforming tube 6, there will be a large difference between the temperature at the weld line 13 and the temperature at the outlet of the reformed gas. It will appear. In addition, the reforming pipe 6 is made to sufficiently contact the catalyst layer 8 at room temperature.
Even if the welding line 13 is provided, the upper end of the reforming tube 6 will be approximately
Due to the high temperature of ℃, the length of the reforming tube 6 is approximately 2
m, the reformer tube 6 will thermally expand by 20 to 30 mm and protrude above the catalyst layer 8.

[Purpose of the Invention] The present invention was made to solve the above-mentioned problems, and its purpose is to prevent the reforming catalyst layer from sinking due to long-term use, and to prevent heat generation due to temperature changes in the reforming tube. ! It is an object of the present invention to provide a reforming device that can perform efficient reforming by following the expansion.

[Summary of the Invention] In order to achieve the above object, in the present invention, a catalyst layer supported by being sandwiched between one perforated plate and the other perforated plate is formed on the outside of the catalyst layer inner tube, and the horizontal cross section thereof has an annular shape. None A flow path that serves as an outbound path for the reformed gas is formed inside the catalyst layer inner tube, and a flow path that has an annular horizontal cross section and serves as a return path for the reformed gas, and is heated from the outside to In a reformer having a built-in reforming tube for reforming gas, the above-mentioned perforated plate is fixed, and the catalyst layer inner tube and the other perforated plate are integrally constituted so that the longitudinal direction of the gas flow path is fixed. An elastic body such as a coil spring or a disc spring is compressed between the catalyst layer inner tube and a fixed part located in the opposite direction, so that the other perforated plate is constantly pushed upward by the elastic body. The present invention is characterized in that no gap is generated between one end of the catalyst layer and the first plate.

[Embodiments of the invention] An embodiment of the present invention shown in the drawings will be described below.

FIG. 1 is a sectional view showing an example of the structure of a reforming apparatus according to the present invention, and the same parts as in FIGS. 3 and 4 are denoted by the same reference numerals. Note that the figure shows the configuration of the upper end and lower end portions of one reforming tube 6.

In the figure, the inside of the reforming tube 6 is a short upper catalyst layer inner tube 2.
1 and an upper perforation plate 17 are integrally molded, and a plurality of protrusions 22 as stoppers are provided on the inner wall of the end plate 12 to fix the upper perforation plate 17 so that it does not move. Further, a lower catalyst layer inner tube 23, which is longer than the upper catalyst layer inner tube 21, is inserted inside the upper catalyst layer inner tube 21 so that it can slide on a concentric axis through a small gap. Furthermore, the center plug 9 is inserted into the inner side of the lower catalyst layer inner tube 23 at three locations on the inner circumferential surface thereof, at the top, middle, and bottom, through equally spaced plug guides 19.
A return bus 10 is formed as a return path for the reformed gas. The lower end of the lower catalyst layer inner tube 23 is connected and fixed to the center plug 9 via the bottom plate 24, and the reformed gas flows out through a partition plate 25 fixed to the gas reformer 1 container. It is connected to pipe 26. Furthermore, on the upper surface side of the partition plate 25, the horizontal cross section is a reformed gas outlet pipe 26.
An annular protrusion 27 is provided with the protrusion 27 at the center, and between the bottom plate 24 and the partition plate 25 inside the protrusion 27, a coil spring 28 made of a heat-resistant material such as Inconel or Hastelloy as an elastic body is installed with a modified gas. A coil spring 28 is installed concentrically with the outflow pipe 26 to keep the lower catalyst layer inner pipe 23 upward.
I'm trying to push it up. On the other hand, a plurality of perforated plate support ribs 3 are provided on the outer wall 29 at the lower end of the lower catalyst layer inner tube 23.
The lower perforated plate 18 is integrally constructed by welding the reforming pipe 6. Upper catalyst layer inner tube 21. Upper perforation plate 17. Heating channel 4 surrounded by lower catalyst layer inner tube 23 and lower perforated plate 18
is filled with catalyst particles to form a catalyst layer 8. Further, a plurality of through holes 31 are provided at a certain interval in the circumferential direction in the lower end portion of the center plug 9, so that the return bus 1
0 and the reformed gas outflow pipe 26 are communicated with each other.

Furthermore, since the upper side of the partition plate 25 is the gas before reforming and the lower part is the gas that has been reformed, the partition plate 25
and the reformed gas outlet pipe 26 are isolated by a bellows 32.

In such a reformer, the upper perforated plate 17 is fixed, and the lower catalyst layer inner tube 20 and the lower perforated plate 18 are integrally configured to be movable in the vertical direction, and the lower catalyst layer inner tube 20 and the lower catalyst layer inner tube 20 and Since the coil spring 28 is compressed between the partition plate 25 which is a fixed part located below, the lower perforated plate 18 is always pushed upward together with the lower catalyst layer inner tube 20 by the elastic force of the coil spring 28. This allows the catalyst layer 8 of the reforming tube 6 to follow thermal expansion of the reforming tube 6 due to long-term operation of the device.
Even if the catalyst layer 8 sinks, as shown in FIG. 4, a gap will not be generated between the upper perforated plate 17 on the high temperature side and the catalyst layer 8, and the problem described above) will be avoided. Without this, it becomes possible to carry out extremely efficient reforming. In this case, the lower opening I [n18 can push up the catalyst layer 8 with a smaller pushing force than when pushing up itself with a coil spring, so the coil spring 28 should have a relatively small diameter. It is extremely economical to use.

FIG. 2 shows the calculated amount of push-up force required by the spring. Here, how much force is applied to the lower end of the catalyst layer 8 when no push-up is performed is known in the well-known literature ("General Theory of Powder Engineering" by Shigeo Miwa, published by Nikkan Kogyo Shimbun, February 1982). Published)) also Jansse
It is shown as a formula for n. This is because the frictional force between the catalyst and the inner surface of the tube in which it is housed moves, so the whole can be supported with less force than its own weight. However, when pushing up, on the other hand, a pushing force sufficient to overcome the frictional force is required.

Figure 2 compares the push-up force by the spring in various cases. The axis also indicates the height h of the catalyst layer 8 as a ratio h/Do to the inner diameter Do of the reforming tube 6. In other words, the higher the height h of the catalyst layer 8, the greater the force F required to lift it. In the figure, curve A is the static support force in the case of a cylindrical catalyst layer without using a double reforming tube, and curve B is the lifting force of the catalyst layer in the case of curve A. However, when this is put inside the catalyst layer, the pushing force changes, and when only the lower perforated plate 18 is pushed up, the curve C
However, if the coil spring 28 of this embodiment is used, the catalyst layer inner tube 23 is also lifted at the same time, so a small amount of force is required for the curve.

In the above embodiment, a case where a plurality of reforming pipes 6 are provided is described, but the present invention is not limited to this, and the present invention can be similarly applied to a case where only one reforming pipe is provided.

Furthermore, although a coil spring is used as the elastic body in the above embodiment, the same effect can be achieved by using a disc spring instead.

[Effects of the Invention] As explained above, according to the present invention, the upper perforated plate is fixed, and the catalyst layer inner tube and the lower perforated plate are integrally configured to be movable in the vertical direction. An elastic body is installed between the tube and the fixed part located below it to prevent the reforming catalyst layer from sinking due to long-term use and to follow the thermal expansion caused by temperature changes in the reformer tube. A highly reliable reforming device capable of extremely efficient reforming can be provided.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a characteristic diagram for explaining the effects of the embodiment, and FIG. 3 is a sectional view showing an example of the configuration of a conventional reforming device. FIG. 4 is a sectional view showing details of the upper part of the reforming tube in FIG. 3. DESCRIPTION OF SYMBOLS 1... Reformer, 1a... Reformer container, 2... Burner, 3... Combustion, 4... Heating channel, 4a... Heat transfer packed bed, 5...・Exhaust gas outlet, 6... Reforming pipe, 7.
... Reformed gas inlet, 8... Catalyst layer, 9... Center plug, 10... Return path, 11... Reformed gas outlet, 12... End plate, 13... Welding line, 14... Cap, 15... Temperature measuring element, 16... Catalyst upper end, 17.18... Perforated plate, 19... Plug guide, 2
0... Lower catalyst layer inner tube, 21... Upper catalyst layer inner tube,
22... Protrusion, 23... Lower catalyst layer inner tube, 24...
... Bottom plate, 25 ... Partition plate, 26 ... Reformed gas outflow pipe, 27 ... Projection, 28 ... Coil spring, 29.
...Outer wall, 30...Perforated plate support rib, 31...Through hole, 32...Bellows.

Claims (2)

[Claims] (1) A catalyst layer supported by being sandwiched between one eyelet plate and the other eyelet plate is formed on the outside of the catalyst layer inner tube, and the horizontal cross section thereof is annular, and the flow path that serves as the outgoing path of the reformed gas is formed as described above. A flow path whose horizontal cross section is annular and serves as a return path for the reformed gas is formed inside the catalyst layer inner tube, and a reforming tube is built in to reform the gas in the outgoing path by heating from the outside. In the reformer, the one eyelet plate is fixed, the catalyst layer inner tube and the other eyelet plate are integrally configured to be movable in the longitudinal direction of the gas flow path, and the catalyst layer inner tube and the other eyeglass plate are configured integrally, and A reforming device characterized in that an elastic body is compressed between a fixed part located in a direction. (2) The reforming device according to claim (1), wherein a coil spring or a disc spring is used as the elastic body.