JPS63126539A - Fuel reformer - Google Patents

Abstract

PURPOSE:To effectively utilize the quantity of heat of a gaseous fuel by arranging a combustion gas passage around a reaction tube, furnishing a combustion gas supply passage around the combustion gas passage through a heat-exchange wall, and providing a heat insulating layer on the outer peripheral surface of the combustion gas supply passage. CONSTITUTION:The heat-exchange part 32 is formed by a combustion gas inductive wall 12, the heat-exchange wall 9, and the inner wall 20 of the reformer. After the double pipe type reaction tube 4 and the reformer catalyst 6 are heated to a specified temp., the fluid to be passed through a fuel pipeline 25 is changed, for example, for raw fuel 24 consisting of a mixture of preheated methane and steam. The raw fuel 24 is heated by the combustion gas in a fuel reformer 1, reforming is carried out in the bed packed with the reformer catalyst 6, and the obtained hydrogen-enriched gas 33 is supplied to the outside of the fuel reformer 1 through the inner reaction tube 3. Besides, the fluid is heated by the heat given by the combustion gas flowing through the combustion gas passage C between the heat-exchange wall 9 and the combustion gas inductive wall 12 through the heat-exchange wall 9.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel reformer, and is particularly used in a fuel reformer that is compact and requires quick load followability, such as a fuel reformer with a single combustion rate or a single tank or two. The present invention relates to a fuel reformer suitable for.

[Prior art]

Unlike fuel reformers conventionally used in the chemical industry, for example, a fuel reformer used in a fuel cell power generation device that is compact and requires quick load followability is disclosed in U.S. Pat. No. 57-7538), by improving the heat transfer performance between the reaction tube, combustion gas, and reformed gas, the reaction tube is made more compact, and as a result, the fuel reformer is made more compact and load followability is improved. We are trying to

[Problem that the invention seeks to solve]

In the above conventional technology, a reaction tube is provided in the center of the fuel reformer,
Combustion gas is circulated around the reaction tube and surrounded by a heat insulating layer to prevent heat radiation. However, since the combustion gas and the heat insulating layer are adjacent to each other, the heat insulating layer becomes thicker, and the fuel reformer There is a problem in that the volume of the heat insulating layer is large.

Furthermore, the combustion gas heats a large area inside the heat insulating layer, and no consideration is given to the loss of heat amount of the combustion gas involved in the heating.

An object of the present invention is to provide a compact fuel reformer that effectively utilizes the calorific value of combustion gas.

[Means for solving problems]

The above purpose is to arrange a fuel gas supply passage between the heat insulating layer and the combustion gas passage through a heat exchange wall, and transfer the heat of the fuel gas released from the combustion gas passage to the outside of the reformer to the fuel gas supply passage. By configuring the fuel gas to be applied to the fuel gas passing through the fuel gas, and by filling the fuel gas supply path with a catalyst, the heat from the combustion gas is utilized to promote a reforming reaction that involves endothermy. , achieved.

That is, the first aspect of the present invention provides a reaction tube that uses a catalyst to cause an endothermic reaction of converting a fuel gas containing a mixture of hydrocarbons, water vapor, etc. into hydrogen-enriched gas, and a combustion method for heating the reaction tube. In a fuel reformer having a combustor that generates gas and a heat insulating layer for preventing heat radiation of the combustion gas, a combustion gas path that is a flow path for the combustion gas is arranged around the reaction tube, A fuel gas supply path, which is a flow path for the fuel gas, is arranged around the combustion gas path via a heat exchange wall, and the heat insulating layer is arranged on the outer peripheral surface of the fuel gas supply path. A second invention is a fuel reformer according to the first invention, which further includes a configuration for filling the fuel gas supply path with a catalyst.

[For production]

According to the first aspect of the present invention, in the fuel gas supply path (hereinafter referred to as the supply path) disposed between the heat insulating layer and the combustion gas path, the fuel gas flowing in the supply path causes the combustion gas to flow in the combustion gas path. The heat dissipated from the is absorbed. This reduces the amount of heat transferred to the insulation layer surrounding the supply channel,
The thickness of the insulation layer is reduced. Further, according to the second aspect of the present invention, by arranging a catalyst in the supply path to cause the fuel gas to undergo an endothermic reforming reaction, the desired raw fuel reforming rate can be increased to several tens of tens of degrees. % of the reforming reaction can be carried out in this supply path, and the remaining reforming reaction can be carried out in the conventional reaction tube, so the length of the reaction tube can be shortened compared to the conventional one.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In FIG. 1, a vertical cross section of a fuel reformer 1 is shown, and the configuration of this embodiment will be explained. A double-tube reaction tube 4 consisting of an outer reaction tube 2 and an inner reaction tube 3 is provided in the center of the fuel reformer 1 .

One end of the reaction tube 2 is fluidly closed.

A catalyst holding plate 5 is attached to the end of the reaction tube inner tube 3 located inside the reaction tube outer tube 2, and a reforming catalyst 6 is filled in the gap between the reaction tube outer tube 2 and the reaction tube inner tube 3. Note that holes 7 are provided in the catalyst holding plate 5. The opening of the reaction tube outer tube 2 is joined to a support plate 8, and the support plate 8 is further joined to a heat exchange wall 9. The end of the heat exchange wall 9 is a flange 10
and is fixed to the bottom plate 11. heat exchange wall 9
A combustion gas guide wall 12 is provided at a location somewhat inside the
A flange 13 at one end thereof is fixed to the bottom plate 11 together with a flange 10 of the heat exchange wall 9. A combustion gas path C is formed in the space between the reaction tube outer tube 2 and the combustion gas guide wall 12 and in the space between the combustion gas guide wall 12 and the heat exchange wall 9. A flange 13 in contact with the inner surface of the combustion gas guide wall 12
A heat insulating member 14 is constructed at a certain length from the center, and a combustor 15 is installed at a position surrounded by the heat insulating member 14. The combustor 15 has several nozzles 16
is provided at a position facing the bottom of the reaction tube outer tube 2. Further, a support member 17 that also serves as heat insulation is provided between the combustor 15 and the bottom plate 11, and an air pipe 18 and a combustion fuel pipe 19 are connected to the combustor 15 by penetrating the bottom plate 11 and the support member 17. It is connected. A reformer inner wall 20 is provided at a position that further surrounds the components surrounding the heat exchange wall 9. The reformer inner wall 20 has a cylindrical shape, and one end thereof has a flange 21 structure, and the flange 21 is joined to the bottom plate 11.

On the other hand, the other end of the reformer inner wall 20 is welded to a semi-elliptical head plate 22, and the head plate 22 is provided at a position covering the support plate 8 with a certain distance therebetween. A fuel gas supply path F is formed in the space between the heat exchange wall 9 and the reformer inner wall 20. Further, the reaction tube inner tube 3 passes through the center of the end plate 22 and is welded and fixed to each other. In addition,
A catalyst filling port 23 is provided in the end plate 22 at a location some distance from the location where the reaction tube inner tube 3 is located. Bottom plate 11
is provided with several raw fuel pipes 25 for supplying raw fuel 24 to the fuel gas supply path F, and an exhaust pipe 2 for guiding combustion exhaust gas 26 from the combustion gas path C to the outside of the fuel reformer 1.
There are several numbers 7. Furthermore, several legs 28 for supporting the main body of the fuel reformer 1 are provided on the bottom fill. The fuel reformer 1 is constructed by covering the outer surface of the bottom plate 11, the reformer inner wall 20, and the end plate 22 with a heat insulating layer 29.

Incidentally, a cross section of the fuel reformer 1 shown in FIG. 1 taken along lines A and -A is shown in FIG. 2. In this configuration, the reaction tube inner tube 3, the reaction tube outer tube 2, the combustion gas guide wall 12, the heat exchange wall 9, and the reformer inner wall 2
0 are arranged concentrically, but a plurality of double-tube reaction tubes 4 may be arranged. In addition, although eight raw fuel pipes 25 and four exhaust pipes 27 are provided point-symmetrically, they may be provided as desired.

Next, the operation of this embodiment will be explained.

First, in order to raise the temperature of the double-tube reaction tube 4 to a predetermined temperature, preheated air 30 and combustion fuel 3 are placed in the combustor 15.
1 is guided to an air pipe 18 and a combustion fuel pipe 19, respectively, and burned in a combustor 15.

A flame is formed from the nozzle 16 and generates high temperature combustion gas. The combustion gas flows through the combustion gas path C between the combustion gas guide wall 12 and the reaction tube outer tube 2, and while raising the temperature of the double tube reaction tube 4 and the reforming catalyst 6, it is further combusted with the heat exchange wall 9. The combustion gas flows through the combustion gas path C between the gas guide wall 12 and is guided to the outside of the fuel reformer 1 through the exhaust pipe 27 as combustion exhaust gas 26 . At this time, in order to uniformly raise the temperature of the double tube reaction tube 4 and the reforming catalyst 6 and shorten the temperature rise time, preheated nitrogen etc. The fluid is passed through the fuel gas supply path F, and the double pipe reaction tube 4 is
The reforming catalyst 6 held therein is directly heated.

The fluid that directly heated the reforming catalyst 6 exits the fuel reformer 1 via the reaction tube inner tube 3. In addition, in the above process, when the fluid for directly heating the reforming catalyst 6 flows through the fuel gas supply path F, it passes through the heat exchange wall 9 and the combustion gas guide wall 12.
Heat exchange wall 9 from the combustion gas flowing in the combustion gas path C between
It receives heat through it and is heated.

That is, by the configuration of the combustion gas guide wall 12, the heat exchange wall 9, and the reformer inner wall 20, the heat exchange section 3, which is a feature of the present invention,
2 is formed.

After the double tube reaction tube 4 and the reforming catalyst 6 reach a predetermined temperature,
The fluid flowing through the raw fuel pipe 25 is switched to, for example, the raw fuel 24 which is a mixture of preheated methane and steam. raw fuel 24
When it enters the fuel reformer 1, it is heated by the combustion gas, and in the packed bed of the reforming catalyst 6, the following reaction occurs, and it becomes a hydrogen-enriched gas 33, which becomes CIt+HzO"""co+
3L "--"""'-river (1) Go +H
20-COz+Hz −−−−−・・・・−−−(
2) Passes through the reaction tube inner tube 3 and is supplied to the outside of the fuel reformer 1. The above is the operation of this embodiment.

According to this embodiment, when the temperature of the fuel reformer is raised, it is possible to heat the double-pipe reaction tube to a high temperature level from the inside and outside, so that the temperature rise time, that is, the start-up time is shortened.
Since heat exchange between raw fuel and combustion gas is possible within the fuel reformer during steady operation, there is an effect that at least the size of the preheater for preheating the raw fuel outside is reduced.

Another embodiment of the present invention will be described with reference to FIGS. 3 and 4.

In FIG. 3, parts that are different from those in FIG. 1 will be partially explained. A feature is that a plate 34 is provided. Unbalanced current prevention plate 3
4 has one longitudinal end in contact with the bottom plate 11 and the other end in contact with the support plate 8
It is provided so as to protrude further toward the mirror plate 22 side. Also, the fourth
As shown in the figure, drift prevention plates 34 are provided at central positions between the raw fuel pipes 25 provided on the bottom plate 11, respectively. Note that the drift prevention plate 34 is connected to the reformer inner wall 2.
0, which prevents the drift prevention plate 34 from colliding with the reformer inner wall 20 due to thermal expansion. With the above configuration, each of the raw fuel 24 sent into the fuel reformer l from the raw fuel pipe 25 is transferred to the reformer inner wall 2.
The fuel gas is inserted into the space between the support plate 8 and the mirror plate 22 while ensuring a flow rate in the fuel gas supply path F surrounded by the heat exchange wall 9 and the two drift prevention plates 34. Thereafter, the raw fuel 24 flows through the packed bed of the reforming catalyst 6, and the hydrogen-enriched gas 3
3 and is supplied to the outside of the fuel reformer 1.

According to this embodiment, by using a member with good thermal conductivity for the drift prevention plate, in addition to the effect of the embodiment shown in FIG. Because the raw fuel is heated more effectively,
This has the effect of further shortening the start-up time of the fuel reformer and further reducing the size of the external preheater that preheats the raw fuel.

Another embodiment of the present invention will be described with reference to FIGS. 5 and 6.

In FIG. 5, parts different from those in FIG. 1 will be partially highlighted and explained. In this embodiment, the reformer inner wall 20 and the semi-elliptical end plate 22 are not welded, but a flange 35 and a flange 36 are provided, respectively, to form a flange connection, and the reformer inner wall near the bottom plate 11 in the fuel gas supply path F 20, a catalyst holding plate 37 is welded and stretched around the catalyst holding plate 37, and a reforming catalyst 38 is filled from the catalyst holding plate 37 to the end plate 22 side. Note that the catalyst holding plate 37 is provided with a hole 39, and a slight gap is provided between the catalyst holding plate 37 and the heat exchange wall 9 so as not to collide with each other during thermal expansion. With the above configuration, the raw fuel 24 that has flowed into the fuel gas supply path F through the raw fuel pipe 25 enjoys the heat transmitted from the combustion gas to the reforming catalyst 38 side through the heat exchange wall 9, and The aforementioned while in contact with 38! 1) and (2) reactions occur.

One of the conditions for obtaining the maximum reforming rate of the raw fuel 24 is to maintain these reactions at a temperature of about 800°C or higher, but since the temperature does not rise to that extent in the packed bed of the reforming catalyst 38, unmodified The quality raw fuel is reformed in a bed packed with a reforming catalyst 6 in a double-tube reaction tube 4 to become a desired hydrogen-enriched gas 33, which is then supplied to the outside of the fuel reformer 1. FIG. 6 shows the AsAζ cross section in FIG. 5.

According to this embodiment, due to the endothermic reaction in the filling 113B of the reforming catalyst, the temperature at the reformer inner wall 20 in contact with the reformer becomes lower, so that the life of the reformer inner wall 20 with respect to temperature is improved. effective.

Another embodiment of the present invention will be described with reference to FIGS. 7 and 8.

In FIG. 7', parts different from those in FIG. 5 will be partially highlighted and explained. This embodiment is characterized in that a drift prevention plate 34 is provided in the fuel gas supply path F holding the reforming catalyst 38 and is connected to the heat exchange wall 9 so as to be positioned perpendicularly to the bottom vi11. The drift prevention plate 34 has one longitudinal end passing through the catalyst holding plate 37 and in contact with the bottom plate 11, and the other end protruding from the support plate 8 toward the mirror plate 22 side. 7th
A in the diagram? The A'l cross section is shown in FIG. Note that the drift prevention plate 34 is connected to the reformer inner wall 20 and the catalyst holding plate 3.
7, to avoid collision with each other during thermal expansion. With the above configuration, the reforming catalyst 38 in the fuel gas supply path F from each raw fuel pipe 25
The amount of raw fuel 24 flowing into the packed bed is evenly distributed, and after the reaction at the reforming catalyst 38 is completed, the gas containing unreacted raw fuel flows through the packed bed of the reforming catalyst 6, and is enriched with hydrogen. The gas 33 is supplied to the outside of the fuel reformer 1.

According to this embodiment, in addition to the effects of the embodiment shown in FIG. This has the effect of extending the life of the catalyst.

Another embodiment of the present invention will be described with reference to FIG.

The embodiment shown in FIG. 9 differs from the embodiment shown in FIG. The fuel is discharged to the outside of the fuel reformer 1 through a bellows 40 provided through the plate 8. At this time, the bellows 40 is flanged to the upper cover 41 which is flanged to the inner wall 20 of the reformer. A highly reliable material is used that can sufficiently follow the thermal expansion and contraction of the heat exchange wall 9 and the upper lid 41 at a temperature of approximately 0.3°C. 1 [41 to belize 40
and are provided to form a combustion gas flow path. In addition, a particle holding plate 43 is welded to the heat exchange wall 9 in the combustion gas path C between the reaction tube outer tube 2 and the heat exchange wall 9. Heat transfer accelerating particles (alumina particles) 44 are held therein. Therefore, the bellows 40 is also used as a filling port for the heat transfer promoting particles 44. The flow velocity of the fuel gas is increased by the presence of heat transfer promoting particles. The above configuration promotes heat transfer from the combustion gas to the reforming catalysts 6 and 38.

According to this embodiment, since the combustion gas guide wall 12 and the combustion gas path C between the combustion gas guide wall 12 and the heat exchange wall 9 are eliminated, the fuel reformer becomes thinner and the installation area is reduced. There is.

〔Effect of the invention〕

According to the present invention, the fuel gas supply path is disposed between the heat insulating layer and the combustion gas path via the heat exchange wall, and heat is exchanged between the combustion gas and the fuel gas, thereby effectively utilizing heat. This makes it possible to reduce the thickness of the heat insulating layer.

Furthermore, by retaining the reforming catalyst in the fuel gas supply path and transferring the reforming reaction to something other than the double-pipe reaction tube, the temperature rise of the reformer inner wall is limited and the thickness of the heat insulating layer is reduced. Since the length of the reaction tube can be reduced, that is, the height of the fuel reformer can be lowered, this has the effect of making the fuel reformer more compact.

[Brief explanation of the drawing]

1, 3, 5, 7, and 9 are longitudinal sectional views of one embodiment of the present invention, and FIG. 2 is a cross sectional view of A, -A', and Figure 4 is a cross-sectional view of A3-A'3 in Figure 3, and Figure 6.
The figure is the As-As cross-sectional view of Figure 5, and Figure 8 is the A of Figure 7.
? It is an A4 cross-sectional view. 1...Fuel reformer, 4...Double tube reaction tube, 6,3
8... Reforming catalyst, 9... Heat exchange wall, 11... Bottom plate, 12... Combustion gas guide wall, 15... Combustor, 20
... Reformer inner wall, 29 ... Heat insulation layer, 34 ... Straight flow prevention plate, 40 ... Bellows, 44 ... Heat transfer promoting particles, C ... Combustion gas path, F ... Fuel gas supply line.

Claims (1)

[Scope of Claims] 1. A reaction tube that uses a catalyst to cause an endothermic reaction to convert fuel gas mixed with hydrocarbons, water vapor, etc. into hydrogen-enriched gas, and a combustion gas for heating the reaction tube. In a fuel reformer having a combustor for generating combustion gas and a heat insulating layer for preventing heat radiation of the combustion gas, a combustion gas path, which is a flow path for the combustion gas, is arranged around the reaction tube, and the combustion gas is A fuel gas supply passage, which is a flow passage for the fuel gas, is arranged around the passage through a heat exchange wall, and the heat insulation layer is arranged on the outer peripheral surface of the fuel gas supply passage. reformer. 2. The fuel reformer according to claim 1, characterized in that a drift prevention plate is disposed within the fuel gas supply path. 3. A reaction tube that uses a catalyst to generate an endothermic reaction that converts a fuel gas mixed with hydrocarbons, water vapor, etc. into hydrogen-enriched gas, and a combustor that generates combustion gas for heating the reaction tube; In the fuel reformer having a heat insulating layer for preventing heat radiation of the combustion gas, a combustion gas path, which is a flow path for the combustion gas, is arranged around the reaction tube, and heat exchange is performed around the combustion gas path. A fuel gas supply path, which is a flow path for the fuel gas, is arranged through a wall, the heat insulating layer is arranged on the outer peripheral surface of the fuel gas supply path, and a catalyst is filled in the fuel gas supply path. A fuel reformer characterized by: 4. The fuel reformer according to claim 3, characterized in that a drift prevention plate is disposed within the fuel gas supply path.