JP5874667B2 - Evaporator, manufacturing method thereof, hydrogen generator and fuel cell system - Google Patents

Description

  The present invention relates to an evaporator for a hydrogen generator, a method for manufacturing the evaporator, a hydrogen generator including the evaporator, and a fuel cell system.

  In general, in a fuel cell power generation system, first, a reforming unit reforms containing hydrogen, carbon dioxide, carbon monoxide, unreacted hydrocarbon compound, steam, and the like by a steam reforming reaction using a hydrocarbon compound and steam as raw materials. Generate gas. Next, carbon monoxide is removed by a carbon monoxide reduction unit such as a shift conversion unit or a selective oxidation unit to generate a fuel gas, and electric power is generated in the fuel cell using the obtained fuel gas.

  The water vapor necessary for the steam reforming reaction is obtained by evaporating water in an evaporation section provided upstream of the reforming section. As the heat required for evaporation, the heat obtained by burning the anode off gas discharged from the fuel cell in the combustion section is usually used (for example, Patent Document 1).

  Hereinafter, the hydrogen generator shown in Patent Document 1 will be described with reference to FIG. FIG. 6 is a longitudinal sectional view of the hydrogen generator.

  The hydrogen generator 1 includes a burner 2, a reforming catalyst 3, a shift catalyst 4, a selective oxidation catalyst 5, an evaporator 8, and a heat insulating material 14 surrounding them. Hydrocarbon and water as raw materials are supplied from the raw material supply port 7, and the combustion gas of the burner 2 is exhausted from the exhaust port 6.

  As the fuel for the burner 2 that supplies reaction heat necessary for the steam reforming reaction, anode off-gas discharged from the fuel cell is used. By the action of the reforming catalyst 3 containing ruthenium as a main component, the raw material reacts with steam to generate reformed gas containing hydrogen, carbon dioxide, carbon monoxide, unreacted methane, steam, and the like. Carbon monoxide contained in the reformed gas reacts with water vapor in the reformed gas by the shift catalyst 4 and is reduced to a concentration of about 1% or less. Further, the reformed gas is mixed with the air supplied from the air supply port 12, and carbon monoxide is selectively burned and removed by the selective oxidation catalyst 5 to generate a hydrogen-containing gas.

  The generated hydrogen-containing gas is supplied from the hydrogen-containing gas outlet 13 to the fuel cell.

  The water vapor supplied to the reforming catalyst 3 is obtained by heating water in the evaporation section 8 with the combustion gas burned in the burner 2, the reaction heat of the modified catalyst or the selective oxidation catalyst, the reformed gas, and the hydrogen-containing gas. . The evaporation unit 8 includes an inner cylinder 9 and an outer cylinder 10 and a spiral rod 11 sandwiched between them.

  The raw material and water supplied from the raw material supply port 7 are heated by the combustion gas generated in the burner 2 while flowing down the spiral space (flow path) 8B separated by the helical rod 11. By disposing the spiral rod 11 between the inner cylinder 9 and the outer cylinder 10, a heat transfer area sufficient to evaporate water is secured.

  In Patent Document 1, as a method of fixing and installing the helical rod 11 between the inner cylinder 9 and the outer cylinder 10, the helical rod 11 is disposed between the inner cylinder 9 and the outer cylinder 10, and then the outer cylinder 10. It is described that the helical rod 11 is crimped by reducing the diameter of the inner cylinder 9 or expanding the diameter of the inner cylinder 9.

Patent No. 4880086

  Even if the diameter of the outer cylinder 10 is reduced or the diameter of the inner cylinder 9 is increased and the helical rod 11 is pressed against the inner cylinder 9 and the outer cylinder 10 as in Patent Document 1, the helical rod 11, the inner cylinder 9 and the outer cylinder are pressed. 10 is not sufficiently watertightly fixed, and water tends to flow in a short-circuit manner through a minute gap between the spiral rod 11 and the inner cylinder 9 or the outer cylinder 10, and the evaporation efficiency tends to be low. In addition, the high-temperature metal smooth surface has high hydrophobicity, and water droplets do not stay in place but rapidly flow down, resulting in a decrease in evaporation efficiency. In order to prevent this, it has been proposed to use a wire mesh. (JP 2010-129411)

  The present invention solves the above-mentioned conventional problems, and provides an evaporator in which a spiral flow path is formed in a watertight manner, a method for manufacturing the evaporator, a hydrogen generation apparatus and a fuel cell system including the evaporator. The purpose is to provide.

An evaporator according to the present invention is an evaporator for evaporating water supplied to a reforming section of a hydrogen generator, and is provided in a spiral shape between an inner cylinder and an outer cylinder, and the inner cylinder and the outer cylinder. And the inner cylinder and the outer cylinder are installed so that the axial direction of the inner cylinder and the outer cylinder are in the vertical direction, and water is supplied to the spiral flow path along the spiral body, and the inner cylinder or the outer cylinder In the evaporator for evaporating water by heat from the outside, the helical body is made of a weld metal that is a molten or solidified metal powder that is connected to the inner cylinder and the outer cylinder.

  An evaporator manufacturing method of the present invention is a method of manufacturing the evaporator of the present invention, comprising a step of filling metal powder between the inner cylinder and the outer cylinder, and high energy from the outer periphery of the outer cylinder. Irradiating a line, melting the outer cylinder of the irradiated part, the outer surface of the inner cylinder opposite to the outer part, and melting the metal powder between the two, and then solidifying the melt to form the weld metal; The helical body is formed by moving the irradiation site in a spiral shape.

  The hydrogen generator of the present invention includes the evaporator of the present invention, and a reforming unit that reacts water vapor from the evaporator and a hydrocarbon gas to generate a hydrogen-containing gas.

  The fuel cell system of the present invention has such a hydrogen generator, and a fuel cell that generates electricity by using a hydrogen-containing gas and air supplied from the hydrogen generator.

  In the evaporator of the present invention, the helical body constituting the helical flow path is made of a weld metal, and this weld metal is welded and integrated with the inner cylinder and the outer cylinder. The joint portion is watertight. For this reason, in the evaporator of this invention, water does not flow short-circuiting, but the evaporation efficiency of water is favorable.

  Since the hydrogen generator and the fuel cell system of the present invention are equipped with such an evaporator, hydrogen is efficiently produced and power generation efficiency is also improved.

It is explanatory drawing which shows the evaporator which concerns on embodiment, and its manufacturing method. It is a partial side view of the evaporator which concerns on another embodiment. It is a partial side view of the evaporator which concerns on another embodiment. It is a partial side view of the evaporator which concerns on another embodiment. It is a partial side view of the evaporator which concerns on another embodiment. It is a longitudinal cross-sectional view of the conventional hydrogen generator. It is a photograph which shows the cross section of the evaporator manufactured by this invention method. It is a photograph which shows the cross section of the evaporator manufactured by this invention method. It is a photograph which shows the cross section of the evaporator manufactured by this invention method.

  With reference to FIG. 1, the evaporator which concerns on embodiment, and its manufacturing method are demonstrated.

  As shown in FIG. 1A, the inner cylinder 20 and the outer cylinder 21 are coaxially arranged, and the metal powder 22 is filled between the inner cylinder 20 and the outer cylinder 21 (FIG. 1B).

  In this embodiment, the bottom of the space between the inner cylinder 20 and the outer cylinder 21 is closed with the bottom lid 23, and then the metal powder 22 is filled. Next, the outer peripheral surface of the outer cylinder 21 is irradiated from the irradiation device 24 with a high energy beam b such as a laser beam, an electron beam or plasma. And the irradiation part of the high energy ray b of the outer cylinder 21, the at least outer peripheral surface of the inner cylinder 20 facing it, and the metal powder 22 between them are melted.

  Further, almost simultaneously with the start of the irradiation of the high energy beam b, the inner cylinder 20 and the outer cylinder 21 and the metal powder 22 between them are rotated around the axis and moved in the axial direction, thereby increasing the energy. The irradiation site of the line b is continuously moved at a constant speed in the spiral direction.

  As a result, the inner cylinder 20 and the outer cylinder 21 that are melted by irradiation with the high energy beam b and the molten portion of the metal powder 22 between them gradually move in the spiral direction. In the part where the high energy ray passes, the melt is solidified to become a weld metal. Therefore, the spiral body 25 (FIGS. 1C to 1E) is formed by moving the irradiation site of the high energy beam b in a spiral shape.

  Thereafter, the bottom lid 23 is removed, and the unmelted metal powder remaining between the inner cylinder 20 and the outer cylinder 21 is taken out from both sides, whereby the spiral channel 27 is provided. The evaporator 26 shown in e) is obtained. FIG. 1C is a longitudinal sectional view of the evaporator 26, FIG. 1D is a side view of the evaporator 26, and FIG. 1E is a sectional perspective view of the evaporator 26. In order to take out the unmelted metal powder, air may be blown with an air gun or the like.

  The material of the inner cylinder 20, the outer cylinder 21, and the metal powder 22 is preferably a corrosion-resistant metal such as stainless steel, titanium, or a titanium alloy, but is not limited thereto. The particle size of the metal powder 22 is preferably about 70 to 250 mesh (about 50 to 200 μm).

  The evaporator 26 manufactured in this way is installed so that the axial direction of the inner cylinder 20 and the outer cylinder is the vertical direction, preferably the vertical direction, and water is supplied to the spiral flow path. In this evaporator 26, the helical body 25 is made of weld metal, is melted and integrated with the inner cylinder 20 and the outer cylinder 21, and the water flowing through the helical flow path 27 does not flow in a short circuit. It flows in the spiral direction along the spiral flow path 27.

  Since the spiral body 25 is made of weld metal obtained by melting and solidifying metal powder, the surface thereof is rough. Therefore, the helical body 25 is excellent in hydrophilicity and has a high water retention capacity. For this reason, the evaporator 26 is excellent in evaporation efficiency.

  The evaporator of the present invention can be automatically and easily manufactured using a welding robot or the like.

  In the above embodiment, the irradiation device 24 is fixed, and the inner cylinder 20, the outer cylinder 21, and the metal powder 22 are moved in the axial direction while rotating. However, the inner cylinder 20, the outer cylinder 21, and the metal powder 22 What is necessary is just to move to a spiral direction relatively with the irradiation apparatus 24, and is not limited to this. For example, the irradiation device 24 may be moved in the spiral direction. Moreover, you may move the irradiation apparatus 24 in a direction parallel to an axial center line, rotating the inner cylinder 20, the outer cylinder 21, and the metal powder 22. FIG.

  Since the spiral body of the evaporator of the present invention is formed by moving the irradiation site of the high energy ray b, the spiral body is not limited to the simple spiral shape shown in FIG. Even a helical body combining a shape portion and another shape portion can be easily formed.

  The spiral body 25A of the evaporator 26A of FIG. 2 is bent so as to form upward wave-front-shaped convex portions 25a at a predetermined interval in the spiral flow path direction. The spiral body 25B of the evaporator 26B in FIG. 3 has small dam-like upward convex portions 25b formed at predetermined intervals in the spiral flow path direction. According to these evaporators 26A and 26B, water flowing along the spirals 25A and 25B receives resistance by the convex portions 25a and 25b, and the flow velocity is reduced, so that water is efficiently evaporated.

  In the evaporator 26C of FIG. 4, a plurality of circumferential bodies 29 made of weld metal extending in the circumferential direction are arranged and arranged at intervals in the circumferential direction at the end of the spiral flow path 27. The orifice 28 is formed between the circumferential bodies 29. The circumferential body 29 is formed in the same manner as the spiral body 25 and has the same structure as the spiral body 25 except that the extending direction is the circumferential direction.

  The gas introduced into the spiral channel 27 from the gas inlet 30 provided in the middle of the spiral channel 27 flows through the spiral channel 27 while being mixed with the water vapor in the spiral channel 27. Thereafter, by passing through the orifice 28, the gas and the water vapor are sufficiently mixed, and the reaction in the catalyst layer can be stabilized by being dispersed at a uniform flow rate in the circumferential direction.

  In the evaporator 26 </ b> D of FIG. 5, a first tongue piece portion 31 is provided downward in the middle of the spiral flow path direction of the spiral body 25, and one side of the first tongue piece portion 31 in the spiral flow path direction is provided. The first opening 33 is provided on the other side, and the second opening 34 is provided on the other side. The first opening 33 is located on the upper side in the spiral flow path direction from the tongue piece portion 31. A downward second tongue piece portion 32 is provided on the edge portion of the first opening 33 opposite to the first tongue piece portion 31. The tongue pieces 31 and 32 are formed in the same manner as the spiral body 25 and have the same structure as the spiral body 25 except that the extending direction is downward.

  The water vapor generated by the evaporation of water and the gas introduced from the inlet 30 provided in the outer cylinder hit the first tongue piece portion 31 and pass through the openings 33 and 34 to promote turbulence. To mix thoroughly. By providing the second tongue piece 32, turbulence is further promoted, and water vapor and gas are sufficiently mixed.

  The hydrogen generator of the present invention can be configured by using the evaporator of the present invention as an evaporator in the hydrogen generator of FIG.

  The fuel cell system of the present invention includes such a hydrogen generator and a fuel cell. This fuel cell generates power by a chemical reaction between hydrogen-containing fuel gas supplied from a hydrogen generator and air.

[Example 1]
1. A stainless steel inner cylinder 20 having an outer diameter of 60.5 mm, a wall thickness of 1.5 mm, and a length of 300 mm; and a stainless steel outer cylinder 21 having an outer diameter of 65.5 mm, a wall thickness of 1.5 mm, and a length of 280 mm. A coaxial arrangement with a gap of 0 mm and a bottom lid 23 are placed, and then filled with stainless steel (SUS316L) powder (commercially available powder sieved with 70 mesh and 250 mesh) having an average particle size of 125 μm. did. Thereafter, the outer cylinder 21 is irradiated with a laser beam from a laser irradiation device (output 2 kW), and the inner cylinder 20, the outer cylinder 21 and the metal powder 22 are moved and rotated at an axial feed rate of 75 mm / min and a rotation speed of 7.5 rpm. The laser irradiation site was moved in the spiral direction. Thereafter, unmelted stainless steel powder was taken out with an air gun. Thereby, the evaporator 26 having the helical body 25 shown in FIGS. 1C to 1E was obtained.

  FIG. 7 is a cross-sectional photograph of the spiral body 25 cut in the axial direction of the evaporator, FIG. 8 is an enlarged photograph thereof, and FIG. 9 is a photograph of the side surface of the spiral body 25 taken. As shown in FIGS. 7 and 8, the spiral body 25 is completely melted and integrated with the inner cylinder 20 and the outer cylinder 21, and it is recognized that it has excellent water tightness. Further, as shown in FIG. 9, the side surface of the spiral body 25 (surface facing the spiral flow path) is rough.

9,20 Inner cylinder 10,21 Outer cylinder 11,25,25A, 25B Spiral body 22 Metal powder 23 Bottom cover 24 High energy ray irradiation device 8, 26, 26A-26D Evaporator 8B, 27 Spiral flow path 28 Orifice 29 Circumference Directional body 30 Gas inlet 31, 32 Opening tongue 33, 34 Opening

Claims (9)

An evaporator for evaporating water supplied to a reforming section of a hydrogen generator,
An inner cylinder and an outer cylinder, and a helical body provided in a spiral shape between the inner cylinder and the outer cylinder,
The inner cylinder and the outer cylinder are installed so that the axial center direction is the vertical direction, water is supplied to the spiral flow path along the spiral body, and water is removed by heat from the inner cylinder inner side or the outer cylinder outer side. In the evaporator to evaporate,
The evaporator is characterized in that the spiral body is made of a weld metal which is a melted and solidified metal powder and is connected to the inner cylinder and the outer cylinder.   The evaporator according to claim 1, wherein the spiral body is provided with upward convex portions at a predetermined interval in the spiral flow path direction.   3. The evaporator according to claim 2, wherein the convex portion has a wave front shape or a small weir shape.   In any one of Claims 1 thru | or 3, the several circumferential direction body which consists of the weld metal extended in the circumferential direction is arranged in the end part of the said spiral flow path at intervals in the circumferential direction, An evaporator characterized in that an orifice is provided between the circumferential bodies.   5. The upper side of the first tongue piece portion in the spiral flow path direction according to claim 1, wherein a first tongue piece portion is provided downward in the middle of the spiral flow path direction of the spiral body. The evaporator is characterized in that the spiral body is provided with a first opening.   6. The second tongue piece portion according to claim 5, wherein a second tongue piece portion is provided downward on an edge portion of the edge portion of the first opening opposite to the first tongue piece portion, and the first tongue piece portion is provided. An evaporator, wherein a second opening is provided in the spiral body on a lower side in the spiral flow path direction. A method of manufacturing an evaporator according to any one of claims 1 to 6,
Filling the metal powder between the inner cylinder and the outer cylinder;
By irradiating a high energy ray from the outer periphery of the outer cylinder, the outer cylinder of the irradiated portion, the outer surface of the inner cylinder facing the outer cylinder, and the metal powder between them are melted, and then the melt is solidified. Forming the weld metal;
And forming the helical body by moving the irradiation site in a spiral shape. The evaporator according to any one of claims 1 to 6,
A hydrogen generator having a reforming unit that reacts water vapor from the evaporator with a hydrocarbon gas to generate a hydrogen-containing gas. A hydrogen generator according to claim 8;
A fuel cell system having a fuel cell that generates electricity by using a hydrogen-containing gas and air supplied from the hydrogen generator.

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