JPH0645442B2 - Reformer - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an improvement of a general gas reformer or a gas-gas heat exchanger.

[Technical Background of the Invention and Problems Thereof] The structure of a commonly used gas reformer will be described with reference to FIG. In the figure, a gas reformer 1 sends combustion gas and combustion air to a burner 2 to burn them in a combustion chamber 3, and a heating fluid generated by the combustion passes through a heating flow path 4 and is discharged to the outside from an exhaust gas outlet 5. . The combustion heat heats the plurality of reforming tubes 6 provided inside the reformer 1.

On the other hand, inside the reforming pipe, a reforming gas passage is provided completely separated from the combustion gas heating passage 4. The reformed gas flowing from the reformed gas inlet 7 flows inside the catalyst layer 8 provided on the inner wall of the reforming pipe 6 and supported by the lower plate 18, rises, and is turned in the opposite direction at the upper end. It flows through the return path 10 formed between the catalyst layer 8 and the center plug 9 and flows out from the reformed gas outlet 11. In the meantime, the reformed gas such as methane and steam is reformed into hydrogen and carbon dioxide. Although there may be only one reforming pipe 6 inside the reformer 1, a plurality of reforming pipes 6 are generally provided as shown in FIG.

FIG. 3 is a detailed cross-sectional view showing an enlarged upper portion of the reaction catalyst layer 8 whose outline has been described with reference to FIG. In the figure, the reforming pipe 6 is made by welding with an end plate 12 and a welding line 13. As described above with reference to FIG. 2, the reforming pipe 6 has a high temperature in its upper portion near the combustion chamber 3,
A cap 14 made of a heat insulating material is placed on the end plate 12. Further, since the weld line 13 is likely to have a defect, the 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 catalyst upper end 16 and reverses at the upper end of the perforation 17 and descends and flows out through the return path 10 formed by the plug guide 19. The eye plate 17 is a perforated plate made of a heat insulating material. This plate 17
Originally, it is provided to prevent the catalyst particles from floating at the upper end 16 of the catalyst layer, but in reality, a gap of size | is provided between the upper end 16 of the catalyst layer and the plate 17 for the following reasons. Will be created.

That is, the first reason is that the reforming pipe 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 pipe 6. The second reason is that the catalyst layer 8 is supported by the lower plate 18 (FIG. 1), but not only the inner diameter of the reforming tube 6 expands due to heat, but also the outside of the catalyst layer inner tube 20. Since the diameter also expands,
The upper end 16 of the catalyst layer is lowered by an amount corresponding to an increase in volume during this period. Further, when the catalyst particles are filled, the reforming pipe 6 is turned upside down and is vibrated while being filled, but the catalyst layer is not fully filled and the catalyst layer is heated and lowered to a high temperature due to the reforming reaction. The upper end 16 sinks and a space of size | is formed between the upper end 16 and the eye plate 17. In such a state, the welding line 13 of the reforming pipe 6 comes out above the upper end 16 of the catalyst layer. As a result, a large difference appears between the temperature of the welding line 13 and the temperature of the catalyst layer 8. Become. For this reason, the welding line 1 is
The reforming operation is performed while monitoring the temperature of No. 3, but if a space is created, the temperature of the upper end 16 of the catalyst layer will not rise so much and the reforming efficiency will deteriorate.

Explaining the above relationship in more detail, when the inside of the reforming pipe 6 is only the flow of the reformed gas, compared to the case where the inside of the reforming pipe 6 is filled with the catalyst, the inside from the wall surface is changed. Since the heat transfer coefficient to the reformed gas becomes very poor, when there is no catalyst inside the welded portion of the reformed pipe 6, there is a large difference between the temperature of the welding line 13 and the temperature of the reformed gas outlet. It will appear. Even if the welding line 13 of the reforming pipe 6 is provided so as to sufficiently contact the catalyst layer 8 at room temperature, the upper end of the reforming pipe 6 is about 100
Due to the high temperature of 0 ° C., when the length of the reforming tube 6 is about 2 m, the reforming tube 6 thermally expands by about 20 to 30 mm and projects above the catalyst layer 8.

[Object of the Invention] The present invention has been made to solve the above problems, and its object is to prevent the reforming catalyst layer from sinking due to long-term use and to follow thermal expansion due to temperature change of the reforming tube. And to provide a reformer capable of performing reforming with extremely high efficiency.

[Summary of the Invention] In order to achieve the above object, according to the present invention, a catalyst layer supported by a perforated plate is formed on the outer side of a catalyst layer inner tube, and a horizontal section thereof has an annular shape and serves as an outward path of reformed gas. However, inside the catalyst layer inner tube, a horizontal section has an annular shape and a flow path for the return path of the reformed gas is formed respectively, and a dome-shaped end plate is welded to the opening at one end, and the above is formed by heating from the outside. In a reformer having a built-in reforming tube for reforming gas on the outward path, the reforming tube is arranged so that the end on the side where the end plate is welded is on the lower side and at the lower position. A burner for heating the reforming tube is provided, and an end side of the reforming tube opposite to the side where the end plate is welded is supported by a tube plate, and a heat insulating cap is provided to cover the outside of the end plate. Attach the sleeve tube on the outside of the reforming tube to surround it,
Further, a heat transfer filling layer is formed between the reforming pipe and the sleeve pipe, and the heat transfer filling layer is supported by a perforated plate provided on the lower end side of the sleeve pipe to support the heat transfer filling layer. The height position of the perforated plate is set higher than the height position of the perforated plate that supports the catalyst layer of the reforming tube.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention shown in the drawings will be described below.
FIG. 1 is a sectional view showing a structural example of a reformer according to the present invention, and the same parts as those in FIGS. 2 and 3 are designated by the same reference numerals. In the figure, a plurality of reforming tubes 6 are arranged inside the reformer vessel 1a such that the end on the side where the end plate 12 is welded is on the lower side, and the reforming vessel 6 is located in the combustion chamber 3 below. Is provided with a burner 2 for heating the reforming tube 6 facing upward as shown in the drawing. Further, a heat insulating cap 14 formed of ceramic, alumina or the like is attached and fixed to the outer side of the end plate 12 by an attaching retainer 21 so as to cover it. Further, on the outside of each of the reforming pipes 6, an upper sleeve pipe 22 and a lower sleeve pipe 25 attached to a lower flange 23 of the upper sleeve pipe 22 via a holding plate 24 are arranged so as to surround the reforming pipes. ing. Here, the upper sleeve pipe 22 is made of the same metal as the reforming pipe 6, that is, heat-resistant steel such as stainless steel or Inconel, and the lower sleeve pipe 25 is made of a polymer material such as ceramic. Then, the perforated plate 26 formed by forming a large number of holes in a heat insulating plate made of a polymer material is supported by the inner protruding portion 27 provided on the lower sleeve tube 25,
A heat transfer material is filled in the heating flow path 4 surrounded by the reforming tube 6, the upper sleeve tube 22, the lower sleeve tube 25, and the plate 26 to form the heat transfer filling layer 4a. In this case, the plate 26 for supporting the heat transfer filling layer 4a is provided at a higher position than the lower plate 17 for supporting the catalyst layer 8 of the reforming tube 6. Thus, the thermal expansion of the reforming tube 6 due to the temperature change can be followed.

On the other hand, the catalyst layer inner pipe 20 is inserted into the reforming pipe 6 by providing ribs at 4 to 6 places on the outer periphery of the middle and upper pipes, and the upper rib 28 is provided on the upper part of the tube sheet 29. The ribs are unfolded to support the weight of the inner tube 20 with this rib.
Further, inside the catalyst layer inner tube 20, ribs 4 to 6 are equally arranged at the upper, middle, and lower three places in order to form a return path 10 which serves as a return path, and the center plug 9 is inserted therein. ing. Further, the tube sheet 29 is provided with a cylindrical wall 30 around the upper portion thereof, on which a partition plate 31 and an end plate 32 located above it are provided.
Are fastened to the flange 33 with cover bolts 34.
Furthermore, the tube sheet 29 has its end placed on a stand 36 provided in the reformer container 1a via a heat insulating material 35. Here, the heat insulating material 35 has a key structure that can freely move only in the radial direction so that the center of the tube sheet 29 is not eccentric, and can cope with the thermal expansion of the tube sheet 29 in the radial direction. The reformed gas for reforming flows from the reformed gas inlet 7 into the inlet chamber 37, flows down the reforming catalyst layer 8, reverses at the lower end, rises in the return path 10, and passes through the outlet pipe 38. The heated fluid generated in the upper chamber 39 and discharged from the reformed gas outlet 11 to the outside is discharged to the outside from the exhaust gas outlet 5 through the heat transfer filling layer 4a.

In such a reforming apparatus, the reforming tube 6 is arranged such that the end on the side where the end plate 12 is welded is on the lower side, and the burner 2 for heating the reforming tube 6 is provided at the lower position thereof. ,
Moreover, since the reforming pipe 6 is supported by the tube sheet 29 on the end side opposite to the side where the end plate 12 is welded,
Due to the subsidence of the catalyst layer 8 due to the operation of the apparatus for a long time as described above, no void is generated between the high temperature side plate 17 and the catalyst layer 8. On the other hand, in this case, the gravity of the catalyst layer 8 itself causes the layer to sink and a gap is generated between the upper plate 18 and the catalyst layer 8. However, this portion is a portion where the temperature is low because of the gas inlet, Since the quality is not so high, the formation of voids does not matter.
Therefore, it is possible to perform the reforming with extremely high efficiency. Further, a cap 14 for heat insulation is attached and fixed to the end plate 12 by an attachment retainer 21, and an upper sleeve pipe 22 and a lower flange 23 of the upper sleeve pipe 22 are attached to the outside of each reforming pipe 6 by a pressing plate 24. The lower sleeve tube 25 attached via the lower sleeve tube 25 is disposed, and the perforated plate 26 is provided on the inner sleeve 27 provided on the lower sleeve tube 25.
Supported by the reforming pipe 6 and the upper sleeve pipe 2
2, the height of the perforated plate 26 that supports the heat transfer filled layer 4a by filling the heat flow path 4 surrounded by the lower sleeve tube 25 and the perforated plate with a heat transfer material to form the heat transfer filled layer 4a. Since the position is set to be higher than the height position of the lower plate 17 which supports the catalyst layer 8 of the reforming tube 6, it is possible to follow the thermal expansion due to the temperature change of the reforming tube 6. It will be possible. That is, the reforming pipe 6 extends downward due to thermal expansion during the operation of the apparatus, but the upper sleeve pipe 22 and the lower sleeve pipe 25 provided outside the reforming pipe 6 are made of metal and are the same as the reforming pipe 6. Since the temperature is about the same, the plate 2 expands to the same extent and follows the thermal expansion of the reforming tube 6 to support the heat transfer packed layer 4a.
Since 6 moves downward, a reforming pipe 6 having good reforming characteristics can be obtained. Furthermore, by removing the upper cover bolt 34 and removing the partition plate 31, it becomes possible to easily perform the replacement work of the catalyst of the catalyst layer 8 inside the reforming pipe 6.

In the above embodiment, the case where a plurality of reforming tubes 6 are provided has been described, but the present invention can be similarly applied to the case where only one reforming tube 6 is provided.

[Effects of the Invention] As described above, according to the present invention, it is possible to prevent the reforming catalyst layer from sinking due to long-term use and to follow the thermal expansion due to the temperature change of the reforming tube to perform extremely efficient reforming. It is possible to provide a highly reliable reformer capable of

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing a constitutional example of a conventional reforming apparatus, and FIG. 3 is a sectional view showing details of an upper portion of a reforming tube shown in FIG. Is. 1 ... reformer, 1a ... reformer container, 2 ... burner, 3
...... Combustion chamber, 4 ...... Heating flow path, 4a ...... Heat transfer packing layer, 5
...... Exhaust gas outlet, 6 …… Reformation 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, 1
6 ... catalyst upper end, 17,18 ... mesh, 19 ... plug guide, 20 ... catalyst layer inner tube, 21 ... mounting retainer,
22 ... upper sleeve tube, 23 ... lower flange, 24
...... Presser plate, 25 ...... Lower sleeve tube, 26 ...... Mesh plate,
27: inner protrusion, 28: rib, 29: tube plate, 3
0 ... Cylindrical wall, 31 ... Partition plate, 32 ... End plate, 33 ...
… Flange, 34… Cover bolt, 35… Insulation,
36 ... Stand, 37 ... Entrance room, 38 ... Exit pipe, 39 ...
… Upper chamber.

Claims (1)

[Claims] 1. A catalyst layer supported by a perforated plate is formed on the outside of the catalyst layer inner pipe, and a flow path, which has an annular horizontal cross section and serves as an outward passage for reforming gas, is formed inside the catalyst layer inner pipe. The horizontal cross-section has an annular shape and the flow paths for the return path of the reformed gas are formed,
In addition, in the reformer having a dome-shaped end plate welded to the opening at one end and incorporating a reforming tube for reforming the gas in the forward path by heating from the outside, the end plate is welded to the reforming tube. A burner for heating the reforming tube is provided at a lower position of the end portion on the side opposite to the side where the end plate is welded. Supported by a plate, a cap for heat insulation is attached so as to cover the outside of the end plate, and a sleeve pipe is arranged outside the reforming pipe so as to surround it, and the reforming pipe and the sleeve pipe are A heat transfer filling layer is formed between the heat transfer filling layer and the heat transfer filling layer, and the heat transfer filling layer is supported by a plate provided on the lower end side of the sleeve tube.
A reforming apparatus, wherein a height position of a perforation supporting the heat transfer packed layer is set to a position higher than a height position of a perforation supporting the catalyst layer of the reforming tube.