JP2010260734A - Reformer and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize and simplify a structure of an oxidizing air feed pipe to be disposed in an auto-oxidation internal-heating reformer. <P>SOLUTION: The auto-oxidation internal-heating reformer is equipped with an outer cylinder 2, an inner cylinder 3 disposed therein and the oxidizing air feed pipe 14 disposed at the center of the inner cylinder 3. A preliminary reforming chamber is formed between the outer cylinder 2 and the inner cylinder 3, and a main reforming chamber is formed inside the inner cylinder 3. The inner cylinder 3 and the oxidizing air feed pipe 14 are each composed of two groove-shaped metal plates 3a and 14a facing each other, respectively, provided that the groove-shaped metal plates 3a and 14a each has flanges 3b and 14b, respectively, and that the flanges 3b and 14b of the groove-shaped metal plates 3a and 14a, respectively, composing the inner cylinder 3 and the oxidizing air feed pipe 14 are quadruply attached and fixed to each other by brazing. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes an outer cylinder, an inner cylinder disposed therein, and an oxidized air pipe disposed along the axial center of the inner cylinder, and a pre-reforming chamber is formed between the outer cylinder and the inner cylinder. The present invention relates to a self-oxidation internal heating type reformer in which a main reforming chamber is formed inside an inner cylinder and a method for manufacturing the same.

Conventionally, a reformer is known in which a mixture of a raw material gas and steam (hereinafter referred to as a raw material-steam mixture) is steam reformed in the presence of a reforming catalyst to generate a hydrogen-rich reformed gas. The hydrogen-rich reformed gas obtained in the reformer is converted to CO ₂ by reacting residual CO (carbon monoxide) with an oxygen-containing gas in the presence of a catalyst by means of CO reduction, and operates at a particularly low temperature. For solid polymer electrolyte fuel cells, CO is reduced to several ppm level before being supplied as fuel.
As the source gas, hydrocarbons such as methane, aliphatic alcohols such as methanol, ethers such as dimethyl ether, city gas, and the like are used. In such a reformer, the reaction formula of steam reforming when methane is used as a raw material gas can be expressed as CH ₄ + 2H ₂ O → CO ₂ + 4H ₂ , and a preferable reforming reaction temperature is 650 to The range is 750 ° C.

  There are an external heating type and an internal heating type as a system for supplying heat necessary for the reforming reaction of the reformer. The external heating type reformer is provided with a heating unit outside, and a reformed gas is generated by reacting a raw material gas and water vapor with a heat source. The internal heating type reformer is provided with a partial oxidation reaction layer on the supply side (upstream side), and the steam reforming reaction layer disposed on the downstream side using the heat generated in the partial oxidation reaction layer is subjected to a steam reforming reaction. Heating to a temperature is performed, and a steam reforming reaction is performed in the heated steam reforming catalyst layer to generate a hydrogen-rich reformed gas.

The partial oxidation reaction can be represented by CH ₄ + 1/2 · O ₂ → CO + 2H ₂ , and the preferred partial oxidation reaction temperature is in the range of 250 ° C. or higher. As an improvement of the internal heating type reformer, a self-oxidation internal heating type reformer is described in Patent Document 1, for example. The reformer of Patent Document 1 is configured in a double cylinder shape having an outer pre-reforming chamber and an inner main reforming chamber, and the pre-reforming chamber has a feed portion of a raw material-steam mixture, a reforming catalyst layer. The main reforming chamber is provided with a supply unit for receiving the discharge from the discharge unit, a mixed catalyst layer in which the reforming catalyst and the oxidation catalyst are mixed, a shift catalyst layer, and a reformed gas discharge unit. The main reforming chamber is further provided with an oxidizing air pipe for supplying oxidizing air to the mixed catalyst layer.

  FIG. 5 is a sectional view schematically showing a conventional self-oxidation internal heating type reformer disclosed in Patent Document 1, and FIG. 6 is a partially broken perspective view of the outer cylinder and the inner cylinder part of FIG. It is. The reformer 1 includes an outer preliminary reforming chamber 22 and two inner main reforming chambers 33 arranged in a double cylinder shape, and is formed thin as a whole. The preliminary reforming chamber 22 and the main reforming chamber 33 are each elongated and have a flat cross section (in the illustrated example, a flat square shape), and the cross sections thereof are similar to each other.

  The preliminary reforming chamber 22 is formed in a plurality of regions between the outer cylinder 2 and the two inner cylinders 3, and the two main reforming chambers 33 are respectively formed inside the two inner cylinders 3. The reforming catalyst layer 4 is provided in the preliminary reforming chamber 22, and the mixed catalyst layer 5 and the shift catalyst layer 6 in which the reforming catalyst and the oxidation catalyst are mixed are provided in the main reforming chamber 33. Is constituted by a high temperature shift catalyst layer 7 and a low temperature shift catalyst layer 8. The catalyst filled in the catalyst layer is generally in the form of particles or honeycomb.

The reforming catalyst constituting the reforming catalyst layer 4 is for steam reforming the raw material gas. For example, a Ni-based reforming reaction catalyst such as NiO—A1 ₂ O or NiO—SiO ₂ .A1 ₂ O ₃ or WO such as ₂ -SiO ₂ · _{A1 2 O 3} and _{NiO-WO 2 · SiO 2 ·} A1 2 O 3 is used. The reforming catalyst constituting the mixed catalyst layer 5 is the same as described above, and the oxidation catalyst uniformly dispersed therein is the temperature required for the steam reforming reaction by causing the source gas in the source-steam mixture to oxidize and generate heat. For example, platinum (Pt), rhodium (Rh), ruthenium (Ru), or palladium (Pd) is used.
The mixing ratio of the oxidation catalyst to the reforming catalyst is selected in the range of about 1 to 15% according to the type of the raw material gas to be steam reformed. For example, when methane is used as the raw material gas, it is about 5% ± 2%. In the case of methanol, the mixing ratio is about 2% ± 1%.

  A raw material-steam mixture supply unit 9 is provided at the lower part of the preliminary reforming chamber 22, and a discharge unit 10 for discharging the effluent after the preliminary reforming is provided at the upper part of the preliminary reforming chamber 22. A supply unit 11 that communicates with the discharge unit 10 of the preliminary reforming chamber 22 is provided above the main reforming chamber 33, and an oxidized air pipe 14 that supplies oxidized air to the central portions of the two main reforming chambers 33. Is formed, and an air ejection portion 15 including a plurality of nozzles is formed at a portion where the oxidized air pipe 14 extends to the mixed catalyst layer 5. The lower portions of the two oxidized air pipes 14 communicate with each other through a casing 16, and a pipe 17 for supplying air is connected to the casing 16. Further, a reformed gas discharge unit 12 is provided below the main reforming chamber 33. The cross section of the oxidized air pipe 14 is formed in a flat shape and is similar to the cross sections of the preliminary reforming chamber 22 and the main reforming chamber 33.

  In the main reforming chamber 33, the mixed catalyst layer 5, the high temperature shift catalyst layer 7 and the low temperature catalyst layer 8 are provided in order from the top to the bottom, but the boundary of each catalyst layer and the low temperature shift catalyst layer 8 including the discharge part 12 are provided. A support plate 18 that supports the catalyst particles is disposed on the lower side. (Similar support plates 18 are also disposed in the pre-reforming chamber 22.) These support plates 18 have a gas flowability but have a hole diameter that does not allow catalyst particles to pass through, and are usually plate-like punch metal. Porous members such as mesh and mesh are used.

JP 2007-126331 A

  In the conventional reformer shown in FIGS. 5 and 6, the oxidized air pipe 14 is extended at the axial center of the inner cylinder 3, and only the lower end thereof is fixed to the casing 16. Therefore, it takes a lot of skill and labor to arrange the oxidized air pipe 14 coaxially accurately in the axial center of the inner cylinder 3 without inclining. Even if it can be arranged accurately coaxially, when the mixed catalyst or shift catalyst is filled in the inner cylinder 3, it is biased toward the side surface of the oxidized air pipe 14 due to uneven pressing force from the pushed-in catalyst. When the applied force is applied, there is a problem that a portion near the tip of the oxidized air tube 14 is fixed in the catalyst in a state in which the portion is inclined from the axial center of the inner cylinder 3.

  When the portion close to the tip of the oxidized air tube 14 is inclined from the axial center of the inner cylinder 3 as described above, the distribution of the amount of oxidized air that permeates from the air ejection portion 15 into the surrounding mixed catalyst layer 5 is also obtained. It becomes uneven. Further, in the conventional reformer, it is necessary to separately perform the pressure detection process such as the pressure resistance test after separately manufacturing the inner cylinder 3 and the oxidized air pipe 14.

In order to solve the above problem, it is also conceivable to connect the inner side of the inner cylinder 3 and the outer side of the oxidized air pipe 14 with some connecting means and perform catalyst filling in the connected state. In this case, however, new additional parts are required and the overall structure becomes complicated. Furthermore, the problem that separate pressure detection steps for the inner cylinder 3 and the oxidized air pipe 14 are not solved.
Therefore, the present invention has an object to solve such problems in the conventional reformer, and provides a reformer having a structure of a new inner cylinder and an oxidized air pipe and a manufacturing method thereof. Objective.

  The reformer of the present invention that solves the above problems includes an outer cylinder, an inner cylinder disposed therein, and an oxidized air tube disposed in the center of the inner cylinder, and is provided between the outer cylinder and the inner cylinder. This is a self-oxidation internal heating type reformer in which a preliminary reforming chamber is formed and a main reforming chamber is formed inside the inner cylinder. The inner cylinder and the oxidized air pipe are both configured by disposing two groove-shaped metal plates facing each other, and the pair of flanges of the inner cylinder sandwich the pair of flanges of the oxidized air pipe, The flanges are fixed to each other by brazing in a state where the flanges are in close contact with each other (claim 1).

  In the reformer in which the inner cylinder and the oxidized air pipe are both flat in the axial cross section, in order to prevent the inner surfaces of the two grooved metal plates constituting the oxidized air pipe from coming into close contact with each other due to external pressure. A plurality of dimples can be protruded from the inner surface of at least one of the grooved metal plates.

A manufacturing method of a reformer of the present invention that solves the above-described problems includes an outer cylinder, an inner cylinder disposed inside the outer cylinder, and an oxidized air pipe disposed along the axial center of the inner cylinder, In this method, a pre-reforming chamber is formed between a cylinder and an inner cylinder, and a main reforming chamber is formed inside the inner cylinder.
The inner cylinder and the oxidized air pipe are both formed by opposingly arranging two grooved metal plates having flanges. At that time, the pair of flanges of the oxidized cylinder are sandwiched between the pair of flanges of the inner cylinder. Thus, the flanges are fixed to each other by brazing in a state where the flanges are in close contact with each other (claim 3).

  In the above reformer manufacturing method, a plurality of stepped portions having a stepped shape can be formed between the flanges of the respective grooved metal plates at a predetermined interval, and each stepped portion can be fixed by brazing. .

  In the reformer of the present invention, as described in claim 1, the inner cylinder and the oxidized air pipe are both configured by disposing two groove-shaped metal plates facing each other, and the inner cylinder and the oxidized air pipe are configured. The flanges of the respective groove-shaped metal plates are fixed to each other by brazing in a state where the flanges are in close contact with each other.

  If comprised in this way, an oxidizing air pipe will be coaxially and correctly arrange | positioned along the axial direction center part of an inner cylinder in the manufacture process of a reformer. When the catalyst is filled between the inner cylinder and the oxidized air pipe, even if a biased force is applied to the side surface of the oxidized air pipe 14 due to the uneven pressing force of the catalyst, the flange of the oxidized air pipe is Since it is fixed to the flange, there is no possibility that the coaxial relationship between the inner cylinder and the oxidized air pipe is broken. Furthermore, since the inner cylinder and the oxidized air pipe are integrated and completed at the same time in the manufacturing process of the reformer, the pressure detecting process such as a pressure resistance test thereafter is only required once.

  In the reformer in which both the inner cylinder and the oxidized air tube have a flat cross section in the axial direction, the inner surfaces of the two groove-shaped metal plates constituting the oxidized air tube are caused by external pressure as described in claim 2. In order to prevent them from sticking to each other, a plurality of dimples can be projected on at least one inner surface of the groove-shaped metal plate. With this configuration, even when an excessive pressing force is applied to the side surface of the oxidized air pipe having a flat cross section when the catalyst is charged, the oxidized air pipe can be prevented from being deformed.

  The manufacturing method of the reformer of the present invention that solves the above-described problem is that, as described in claim 3, the inner cylinder and the oxidized air pipe are both arranged so as to face each other with two groove-shaped metal plates having flanges. In this case, the pair of flanges of the oxidized air pipe are sandwiched by the pair of flanges of the inner cylinder, and each flange is brazed and fixed to each other in a state of being in close contact with the four layers.

  According to the manufacturing method of the present invention, the oxidized air pipe can be coaxially and accurately disposed along the axial center portion of the inner cylinder. Further, the inner cylinder and the oxidized air pipe can be easily integrated without using any special parts. Moreover, the pressure detection process such as a pressure test is only required once.

  In the reformer manufacturing method, as described in claim 4, a plurality of stepped portions having a step shape are formed at predetermined intervals between the flanges of the grooved metal plates, and the stepped portions are brazed. Can be fixed.

  Generally, the reformer uses a brazing method using nickel brazing when fixing a long and thin joining portion of a plurality of stainless steel plates to each other. At that time, a powdery nickel brazing is applied to a gel paste. A paste-like brazing material mixed with is used. Then, a brazing material is placed (applied) at a plurality of locations at predetermined intervals along the joining portion and brazed in a heating furnace.

  However, when brazing material is placed on the upper surface of the joint part, part of it penetrates into the gap of the joint part due to its fluidity, but the remaining part flows down in the direction of gravity and diffuses, and adhesion of the brazing material at the joint part is difficult. There is a problem of non-uniformity. Also, when the brazing filler metal is dried in the furnace, the adhesiveness between the brazing filler metal and the joint will decrease, causing vibrations and tilts during transport to the heating furnace, etc. May occur.

  However, when a stepped step portion is formed between the flanges to be brazed as in the above manufacturing method, when a paste-like brazing material is placed on the stepped portion, the phenomenon of flow-down in the gravitational direction is eliminated as in the prior art. This is presumed to be due to the phenomenon that the paste-like brazing material tries to stay there due to the action of the surface tension generated at the corner of the step.

  In addition, when the stepped step portion is formed in the brazed portion as in the above manufacturing method, when the paste-like brazing material is heated and dried, the brazing material remains in the corner portion of the step (to the corner angle). The brazing material does not peel off from the joined portion even if vibrations or impacts are applied during transportation to a heating furnace or the like due to the intrusion action. When brazing in a heating furnace, the brazing material changes to a liquid exceeding the melting point, and the brazing material penetrates into the gaps between the parts processed in a staircase shape by capillary action. As a result, brazing with a predetermined strength can be achieved without applying a brazing material to the entire joint portion.

The perspective view which shows the part of the inner cylinder and oxidation air pipe which are the principal parts of the reformer of this invention. Sectional drawing which combined the outer cylinder part with the part seen from the AA arrow of FIG. 1, and the BB arrow. The top view of the groove-shaped metal plate 14a of an oxidation air pipe. The partial perspective view which expands and shows the part which formed the level | step-difference part 20 in the junction part of the modifier of FIG. Sectional drawing which shows the conventional auto-oxidation internal heating type reformer typically. FIG. 6 is a partially broken perspective view of the outer cylinder and the inner cylinder part of FIG. 5.

  Next, the best embodiment of the present invention will be described based on the drawings. The reformer 1 of the present embodiment is different from the reformer 1 of FIGS. 5 and 6 described above only in the structure of the inner cylinder 3 and the oxidized air pipe 14 and the joint portion thereof, and the rest is configured similarly. Is done. Therefore, the same parts as those of the reformer of FIGS.

  The inner cylinder 3 is configured by disposing two groove-shaped metal plates 3a such as two stainless steel plates having the same dimensions and having a flange 3b on both sides and a substantially groove-shaped (U-shaped) cross section. By closely overlapping the flanges 3b of the metal plate 3a, a space having a flat cross section is formed inside thereof, and the oxidized air tube 14 is disposed in the space and filled with a catalyst. As shown in FIG. 5, the inner cylinder 3 has a large cross section in a small region at the top thereof and a small cross section at the other lower portion, and shifts from a large section to a small section. The shoulder portion 3c is shown in FIG.

  The oxidized air pipe 14 is also configured by arranging two elongated metal plates 14a made of aluminum or stainless steel having the same dimensions and having a flange 14b in cross section in a substantially groove shape (U shape). By closely overlapping the flanges 14b of the metal plate 14a, a space having a flat cross section is formed inside thereof, and a flow passage through which oxidizing air flows is formed in the space.

  The flange 3b of the two groove-shaped metal plates 3a forming a large cross-section portion (a small area portion) in the inner cylinder 3 constitutes a double overlap portion that is in close contact with each other, and its double overlap The joining portions are fixed to each other by brazing. On the other hand, the flanges 3b of the two grooved metal plates 3a that form a small section (most remaining region) of the inner cylinder 3 and the flanges of the two grooved metal plates 14a that form the oxidized air tube 14 14b constitutes a quadruple overlapped portion that is in close contact with each other, and the four overlapped portions are fixed to each other by brazing. By this fixing, the oxidized air pipe 14 is accurately disposed coaxially along the center of the inner cylinder 3, and the inner cylinder 3 and the oxidized air pipe 14 are integrated with each other. In addition, the axial section of the inner cylinder 3 and the oxidized air pipe 14 can be made constant, and in that case, the flanges of both are formed in a four-layer overlapped portion in close contact with each other. It is also possible to fix the overlapping parts of each other by brazing.

  FIG. 3 is a front view of the grooved metal plate 14a for forming the oxidized air tube 14 shown in FIGS. The groove-shaped metal plate 14a has a flat portion 14f and a tapered portion 14c formed on the periphery thereof. That is, the entire portion is formed in a substantially dish shape by the flat portion 14f and the tapered portion 14c. On the other hand, an air ejection portion 15 composed of a plurality of nozzles (small holes) is formed on the upper portion of the flat portion 14f. Furthermore, a plurality of dimples 14d are dispersed and formed on the inner surface side of the flat portion 14f.

  These dimples 14d come into contact with each other at the tips of two groove-shaped metal plates 14a arranged opposite to each other. On the other hand, a plurality of notches 14e are formed at predetermined intervals on the outside of the tapered portion 14c of the groove-shaped metal plate 14a, that is, on the peripheral edge of the groove-shaped metal plate 14a. These cutout portions 14e form a step portion of a joint portion described later.

  Next, a method for fixing the inner cylinder 3 and the oxidized air pipe 14 shown in FIG. 1 will be described. For fixing, a brazing method typically used in this field is adopted. In this embodiment, the flanges 14b of the two groove-shaped metal plates 14a forming the oxidized air tube 14 are first placed on top of each other so as to face each other and assembled into the oxidized air tube 14 having a flat cross section. Next, the flanges 3b of the two groove-shaped metal plates 3a forming the inner cylinder 3 are overlapped on the outer side of the flange 14b of the assembled oxidized air tube 14 to form a quadruple overlapped portion serving as a joint portion. In this state, the oxidized air pipe 14 is accurately coaxially disposed along the center portion of the inner cylinder 3.

  Next, the horizontal joint is leveled, a paste-like nickel brazing material is placed (applied) on the upper side, and brazing is performed in a heating furnace. In the present embodiment, a method is adopted in which step portions are formed in advance between the flanges 3b and 14b at predetermined intervals along the longitudinal direction of the joint portion, and a paste-like brazing material is placed in each step portion.

  FIG. 4 is an enlarged partial perspective view showing a portion where the stepped stepped portion 20 is formed in the joint portion. The left stepped portion 20 in the drawing is in a state before the paste-like brazing material 21 is placed. The step portion 20 shows an example in which a paste-like brazing material 21 is placed.

  In order to form the stepped portion 20, the grooved metal plate 3a forming the inner cylinder 3 is provided with a notch 3d, and the grooved metal plate 14a forming the oxidized air tube 14 is cut as shown in FIG. A notch portion 14e is provided. The lengths in the longitudinal direction of the joints in these notches 3d and 14e are shown in the figure in order to form a plurality of steps or corners in each contact portion of the grooved metal plates 3a and 14a that are superimposed four times. Thus, the dimensions are different from each other.

  When the paste-like brazing material 21 is placed on the stepped portion 20 in the joint as shown in the figure, the phenomenon that the paste-like brazing material 21 flows down in the direction of gravity can be prevented as described above. Further, due to the action that the paste-like brazing material 21 stays at the corner portion of the step (the entry action into the corner), even if vibration or impact is applied during conveyance to a heating furnace or the like, the brazing material 21 is removed from the joint portion. There is no fear of peeling. When brazing is performed in the heating furnace, the brazing material 21 changes to a liquid exceeding the melting point, and the brazing material penetrates into the gaps between the parts processed in a staircase shape by capillary action. Thereby, even if it does not apply | coat a brazing material to the whole junction part (over a longitudinal direction full length), favorable brazing can be achieved.

  The reformer and the manufacturing method thereof of the present invention can be used for a reformer that supplies hydrogen-rich reformed gas as fuel to a fuel cell.

DESCRIPTION OF SYMBOLS 1 Reformer 22 Preliminary reforming chamber 2 Outer cylinder 33 Main reforming chamber 3 Inner cylinder 3a Groove-shaped metal plate 3b Flange 3c Shoulder part 3d Notch

4 reforming catalyst layer 5 mixed catalyst layer 6 shift catalyst layer 7 high temperature shift catalyst layer 8 low temperature shift catalyst layer 9 supply unit 10 discharge unit 11 supply unit

12 Discharge unit 14 Oxidized air pipe
14a Channel metal plate
14b flange
14c Taper part
14d dimple
14e Notch
14f flat part

DESCRIPTION OF SYMBOLS 15 Air ejection part 16 Casing 17 Piping 18 Support plate 20 Step part 21 Brazing material

Claims (4)

An outer cylinder 2, an inner cylinder 3 disposed inside the outer cylinder 2, and an oxidized air pipe 14 disposed at the center of the inner cylinder 3, and a preliminary reforming chamber is formed between the outer cylinder 2 and the inner cylinder 3. In the self-oxidation internal heating type reformer in which the main reforming chamber is formed inside the inner cylinder 3,
The inner cylinder 3 and the oxidized air pipe 14 are both configured by opposingly arranging two grooved metal plates (3a, 14a) having flanges (3b, 14b) on both sides, and each flange 3b of the inner cylinder 3 is disposed. The reformer is characterized in that the flanges 14b of the grooved metal plates 14a constituting the oxidized air pipe 14 are sandwiched and fixed to each other by brazing in a state of being in close contact with each other. In claim 1,
In order to prevent the inner surfaces of the two groove-shaped metal plates 14a constituting the oxidized air tube 14 from coming into close contact with each other due to external pressure, a plurality of dimples 14d are projected on at least one inner surface of the groove-shaped metal plates 14a. A reformer characterized by comprising: An outer cylinder 2, an inner cylinder 3 disposed inside the outer cylinder 2, and an oxidized air pipe 14 disposed along the center of the inner cylinder 3, and a preliminary reforming chamber is provided between the outer cylinder 2 and the inner cylinder 3. In the manufacturing method of the reformer of the self-oxidation internal heating type in which the main reforming chamber is formed inside the inner cylinder 3,
Both the inner cylinder 3 and the oxidized air pipe 14 are arranged so that two grooved metal plates (3a, 14a) face each other, and the pair of flange portions 14b of the oxidized air chamber 14 are sandwiched between the pair of flanges 3b of the inner cylinder 3. At this time, the flanges (3b, 14b) in the grooved metal plates (3a, 14a) forming the inner cylinder 3 and the oxidized air pipe 14 are fixed to each other by brazing in a state of being in close contact with each other. A method for manufacturing a reformer.   4. A plurality of stepped portions 20 each having a step shape are formed at predetermined intervals between the flanges (3b, 14b) of the grooved metal plates (3a, 14a) according to claim 3, and the stepped portions 20 are brazed. A method for producing a reformer, characterized in that the reformer is fixed by the method.

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