JP5640395B2 - Hydrogen generator - Google Patents

Description

  The present invention relates to a hydrogen generator that produces a product gas containing a high concentration of hydrogen using a hydrocarbon-based fuel such as city gas or LPG as a raw material gas.

  The fuel cell power generation device is mainly configured by a hydrogen generation device that generates a product gas containing high-concentration hydrogen and a fuel cell that generates power using hydrogen generated by the hydrogen generation device.

  The hydrogen generator uses a hydrocarbon-based fuel such as city gas or LPG as a raw material gas, and performs a steam reforming reaction between the raw material gas and water using a reforming catalyst, thereby producing hydrogen, methane, carbon monoxide (10 to 10). About 15%), a reforming section that generates reformed gas containing carbon dioxide and water vapor as a component, and a CO removal section that removes carbon monoxide having a poisoning effect on the fuel cell from the reformed gas. Is formed. Here, when a polymer electrolyte fuel cell is used as the fuel cell, it is necessary to remove the carbon monoxide concentration contained in the reformed gas to about 10 ppm. Therefore, the CO removal unit uses a shift catalyst to shift. The carbon monoxide concentration is reduced to about 10 ppm or less by oxidizing the carbon monoxide by a selective oxidation reaction by mixing with oxygen using a selective oxidation catalyst by removing the carbon monoxide to about 0.5% by the reaction. In general, it is formed of a two-stage constituent part of the selective oxidation part that reduces to a minimum.

  Various devices have been proposed as hydrogen generators from the viewpoints of miniaturization, high efficiency, high durability, improved operational stability, low cost, etc. Is realized by minimizing heat loss by integrating a reforming section and a CO removal section and arranging a heating burner therein to optimize the heat balance in the apparatus.

In order to realize a small and highly efficient hydrogen generator, how to effectively transfer the heat from the internal heating burner to the catalyst and bring the whole catalyst to a temperature state where a good catalytic reaction can be performed. It becomes a point. In particular, the reforming section that performs the steam reforming reaction by setting the temperature to 600 ° C. to 700 ° C. is in a high temperature state, so if heat is transferred to the reforming catalyst, heat is released outside the hydrogen generator. This leads to a reduction in reforming efficiency. Here, the reforming efficiency is the ratio of the amount of raw material gas required for producing hydrogen to the amount of necessary hydrogen. How much the amount of raw material gas required is reduced, that is, a burner. How to reduce the amount of heating in the steel and balance the heat leads to improvement of the reforming efficiency. In order to reduce the amount of heating in the burner, heat transfer from the high-temperature combustion gas generated in the burner to the reforming catalyst is promoted to reduce the heat transfer section, and heat is applied so that the catalyst is not uneven. It is necessary to reduce the amount of the catalyst and reduce the size of the apparatus by setting the temperature of the entire catalyst so that the catalyst performance is good. As a means of promoting heat transfer from the combustion gas to the catalyst, a method of increasing the heat transfer coefficient from the combustion gas to the reforming catalyst by narrowing the width of the combustion gas passage to increase the flow speed of the combustion gas There is. However, when the flow path width is narrowed, when a radial shift occurs in the positional relationship between the two cylindrical structures constituting the inner and outer peripheral surfaces of the combustion gas flow path, even a slight shift causes a narrow flow. It becomes a big ratio with respect to a path width, and the dispersion | variation in the flow path width of the circumferential direction becomes large. When the variation in the flow path width is large, the combustion gas has a fast flow rate and a slow flow rate, resulting in a difference in heat transfer amount from the combustion gas to the reforming catalyst. If there is a difference in the amount of heat transfer, there will be a part where the reforming catalyst is heated to a high temperature and a part where the temperature is not so high. The reactivity of the reforming catalyst is not linear with respect to the temperature of the reforming catalyst. The higher the temperature, the smaller the rate at which the reactivity improves. In other words, if the temperature of the reforming catalyst becomes uneven and a high-temperature part is formed, the heat is wasted without being improved in reactivity for the amount of heat transferred, and a certain amount of hydrogen is reduced. If it is to be produced, a large amount of heating in the burner is required, and the reforming efficiency is deteriorated. Further, when the temperature of the catalyst is increased, catalyst species such as a catalytic noble metal dispersed on the catalyst are aggregated by sintering and the dispersibility is deteriorated, and the reactivity of the catalyst is deteriorated due to the deterioration of the catalytic action. Therefore, there is a possibility of affecting the durability of the catalyst. Furthermore, the temperature of the catalyst is increased and the temperature is uneven in the circumferential direction. This means that the cylindrical structure that forms the partition wall between the combustion gas and the catalyst layer is also partially heated, causing uneven temperature in the circumferential direction. End up. When temperature unevenness occurs in the circumferential direction of the cylindrical structure, stress is generated in the structure due to the temperature difference. In particular, since the allowable stress value of the material forming the structure is low in the high-temperature portion, if stress is applied, the durability of the structure may be affected.

  In the conventional configuration for the above problem, for example, a proposal shown in Patent Document 1 has been made.

  FIG. 7 shows a conventional hydrogen generator described in Patent Document 1. In FIG. As shown in FIG. 7, a plurality of convex projections are formed on the surface of the cylindrical wall member, and the tip of the projection is brought into contact with another cylindrical wall member located on the outer side to increase the height of the projection. Accordingly, a uniform combustion gas flow path width is formed, and heat transfer from the combustion gas to the catalyst is made uniform.

Japanese Patent No. 4068111

  However, in the conventional configuration, when trying to make the tip of the plurality of protrusions abut against another cylindrical wall member, parts accuracy is required, and difficulty in assembling during production is expected. Manufacturing costs could be high.

  The present invention has been made in view of the above points, and promotes and equalizes heat transfer from the combustion gas to the reforming catalyst in the hydrogen generator in a configuration that also takes manufacturability and manufacturing costs into consideration. Thus, an object of the present invention is to provide a small and highly efficient hydrogen generator.

In order to solve the above problems, a hydrogen generator according to the present invention has multiple cylindrical structures each having a different diameter and arranged so that the central axes overlap with each other, and a burner for heating the cylindrical structures. Combustion in which combustion gas flows from a burner between a first cylindrical structure located on the innermost side of the cylindrical structure and a second cylindrical structure located on the outer side of the first cylindrical structure By forming a gas flow path and supplying a mixed gas of water vapor and source gas between the second cylindrical structure and the third cylindrical structure located outside the second cylindrical structure. A reforming catalyst layer that generates a reformed gas containing hydrogen by performing a steam reforming reaction, and a flow direction of the combustion gas flowing through the combustion gas flow path;
A cylindrical hydrogen generator in which the mixed gas flowing through the reforming catalyst layer and the flow direction of the reformed gas face each other, and a protrusion or a spacer for maintaining the interval between the combustion gas channels is provided as a combustion gas channel. A plurality of protrusions or spacers are provided on the outer peripheral surface of the first cylindrical structure or the inner peripheral surface of the second cylindrical structure at the upstream and downstream portions of the flow of the combustion gas flowing through The upstream part is more hydrogen generator than the downstream part.

  Specifically, the number of protrusions or spacers per unit area of the first cylindrical structure or the second cylindrical structure, or the circumferential direction of the first cylindrical structure or the second cylindrical structure The number of protrusions or spacers and the protrusions or spacers were viewed from one end of the combustion gas flow path to the other end of the combustion gas flow path in parallel to the central axes of the first cylindrical structure and the second cylindrical structure. The number of protrusions or spacers visible in the case is larger in the upstream part of the flow of the combustion gas flowing in the combustion gas flow path than in the downstream part.

  As a result, in the upstream portion of the combustion gas passage through which high-temperature combustion gas flows, the combustion gas passage width can be configured as uniformly as possible in the circumferential direction, and heat transfer from the combustion gas to the reforming catalyst layer is promoted. And uniformization can be realized.

In addition, a plurality of cylindrical structures each having a different diameter and arranged so that the central axes overlap with each other and a burner for heating the cylindrical structures are provided, and the first innermost one of the plurality of cylindrical structures is located. A combustion gas flow path through which combustion gas from the burner flows is formed between the cylindrical structure and the second cylindrical structure located outside the first cylindrical structure, and the second cylindrical structure A reformed gas containing hydrogen is produced by a steam reforming reaction by supplying a mixed gas of steam and a raw material gas between the first cylindrical structure and the third cylindrical structure located outside the second cylindrical structure. And a reforming catalyst layer, wherein the flow direction of the combustion gas flowing through the combustion gas flow path is opposed to the flow direction of the mixed gas and the reforming gas flowing through the reforming catalyst layer. the projections or spacers for maintaining a distance between the combustion gas flow passage, the combustion gas Into an upstream portion and a downstream portion of the flow of combustion gases flowing through the duct, a plurality, provided on the outer peripheral surface or inner peripheral surface of the second cylindrical structure of the first cylindrical structure, the interval of the combustion gas passage The value obtained by subtracting the height dimension of the plurality of protrusions or spacers from the dimension of is a hydrogen generator in which the upstream part is smaller than the downstream part.

  This makes it possible to configure the combustion gas passage width as uniform as possible in the circumferential direction in the upstream portion of the combustion gas passage through which the high-temperature combustion gas flows, in addition to the configuration in which the number of protrusions or spacers is changed. Promotion and uniformity of heat transfer to the reforming catalyst layer can be realized.

  According to the present invention, in the configuration in which the cylindrical structure constituting the combustion gas flow path is provided with protrusions and spacers to define the combustion gas flow path width, high-temperature combustion gas flows without impairing manufacturability, In the part governing the heat transfer performance to the high temperature portion of the reforming catalyst layer, it becomes possible to uniformly configure the combustion gas flow path width in the circumferential direction, and the heat transfer promotion from the combustion gas to the reforming catalyst layer, It enables uniform heat transfer in the circumferential direction. Therefore, by reducing the temperature of the reforming catalyst in the circumferential direction, it is possible to reduce the size of the entire catalyst by effectively using it, and at the same time, by preventing partial heating of the reforming catalyst and the structure, the durability of the catalyst and the structure is improved. Thus, a small, highly efficient, and highly durable hydrogen generator can be realized.

Schematic configuration diagram showing a hydrogen generator in Embodiment 1 of the present invention BRIEF DESCRIPTION OF THE DRAWINGS Schematic block diagram which shows the hydrogen generator in Embodiment 1 of this invention (a) The external view which shows an example of a protrusion (b) The external view which shows the example of another protrusion Characteristic diagram of numerical analysis result showing relationship between combustion gas flow path width and conversion rate in Embodiment 1 of the present invention Schematic configuration diagram (a1) showing the hydrogen generator in Embodiment 1 of the present invention (a1) Schematic configuration diagram showing the combustion gas flow path when there are no deviations with three projections (a2) When there are deviations with three projections (B1) Schematic configuration diagram showing the combustion gas flow path when there are no deviations with 8 projections (b2) Combustion gas flow path when there are 8 projections and deviations Schematic configuration diagram FIG. 1 is a schematic configuration diagram showing a hydrogen generator in Embodiment 1 of the present invention. (A) A diagram showing a combustion gas flow path when the number of protrusions when viewed in the flow direction of the combustion gas is eight (b1) combustion gas. (B2) External view showing an example of the state of the projection when the number of projections is 8 when viewed in the flow direction of the gas (b2) The projection of the projection when the number of projections is 8 when viewed in the flow direction of the combustion gas External view showing another example of the state (b3) External view showing another example of the state of the protrusion when the number of protrusions is 8 when viewed in the flow direction of the combustion gas (b4) Flow direction of the combustion gas External view showing another example of the state of the protrusion when the number of protrusions when viewed at 8 is 8 Schematic configuration diagram showing a hydrogen generator in Embodiment 2 of the present invention Schematic configuration diagram showing a conventional hydrogen generator

1st invention has the multiple cylindrical structure body which is each arrange | positioned so that a diameter differs and a central axis may overlap, and the burner which heats the said cylindrical structure body, The innermost inside of the said multiple cylindrical structure body A combustion gas flow path through which combustion gas from the burner flows is formed between the first cylindrical structure located at the first cylindrical structure and the second cylindrical structure located outside the first cylindrical structure. A steam reforming reaction by supplying a mixed gas of steam and a raw material gas between the second cylindrical structure and a third cylindrical structure located outside the second cylindrical structure. A reforming catalyst layer for generating a reformed gas containing hydrogen, the flow direction of the combustion gas flowing through the combustion gas flow path, and the mixed gas and the reformed gas flowing through the reforming catalyst layer. A cylindrical hydrogen generator facing the flowing direction, wherein the combustion gas The projections or spacers for maintaining a distance between the flow path, into an upstream portion and a downstream portion of the flow of the combustion gas flowing through the combustion gas flow passage, a plurality, the outer peripheral surface or the of the first cylindrical structure provided on the inner peripheral surface of the second cylindrical structure, the number of the plurality of the protrusions or spacers, said upstream portion is a hydrogen generating apparatus characterized by greater than said downstream portion.

  According to a second aspect of the invention, in particular, in the first aspect of the invention, the number of the plurality of protrusions or spacers is the number per unit area of the first cylindrical structure or the second cylindrical structure. The upstream portion of the flow of the combustion gas flowing through the combustion gas flow path is more than the downstream portion.

  According to a third invention, in particular, in the first or second invention, the number of the plurality of protrusions or spacers is the number in the circumferential direction of the first cylindrical structure or the second cylindrical structure. The upstream part of the flow of the combustion gas flowing through the combustion gas flow path is more than the downstream part.

  In a fourth aspect of the present invention, in particular, in any one of the first to third aspects, the number of the plurality of protrusions or spacers may be the number of the protrusions or spacers, the first cylindrical structure and the second cylindrical shape. When viewed from one end of the combustion gas flow path to the other end of the combustion gas flow path in parallel to the central axis of the structure, the number of the protrusions or spacers that can be seen is the number of the combustion gas flowing through the combustion gas flow path. The upstream part of the flow is characterized by being more than the downstream part.

According to a fifth aspect of the invention, in particular, in the third or fourth aspect of the invention, the number of the protrusions or spacers in the circumferential direction, the protrusions or spacers are the first cylindrical structure and the second cylindrical structure. The number of protrusions or spacers seen when viewed from one end of the combustion gas flow path to the other end of the combustion gas flow path is parallel to the central axis of the combustion gas flow path upstream of the flow of the combustion gas flowing through the combustion gas flow path. the part is characterized in that it is 10 from 4.

A sixth invention includes a plurality of cylindrical structures each having a different diameter and arranged so that the central axes overlap with each other, and a burner for heating the cylindrical structures, and the innermost of the plurality of cylindrical structures. A combustion gas flow path through which combustion gas from the burner flows is formed between the first cylindrical structure located at the first cylindrical structure and the second cylindrical structure located outside the first cylindrical structure. A steam reforming reaction by supplying a mixed gas of steam and a raw material gas between the second cylindrical structure and a third cylindrical structure located outside the second cylindrical structure. A reforming catalyst layer for generating a reformed gas containing hydrogen, the flow direction of the combustion gas flowing through the combustion gas flow path, and the mixed gas and the reformed gas flowing through the reforming catalyst layer. A cylindrical hydrogen generator facing the flowing direction, wherein the combustion gas The projections or spacers for maintaining a distance between the flow path, into an upstream portion and a downstream portion of the flow of the combustion gas flowing through the combustion gas flow passage, a plurality, the outer peripheral surface or the of the first cylindrical structure provided on the inner peripheral surface of the second cylindrical structure, minus the plurality of height of the protrusions or spacers from the dimension of the interval of the combustion gas flow path, said upstream portion is less than said downstream portion Is a hydrogen generator characterized by

  In a seventh aspect of the invention, in particular, in any one of the first to sixth aspects of the invention, the protrusion or spacer presses the first cylindrical structure or the second cylindrical structure from one side to form a substantially conical shape. Or a round bar having a short length is arranged such that the length direction of the round bar is directed to the flow direction of the combustion gas flowing through the combustion gas flow path. It is what.

In an eighth invention, in particular, in any one of the first to seventh inventions, the burner is provided inside the first cylindrical structure, and the second cylindrical structure and the second cylindrical structure are provided. A water evaporation section that generates the water vapor by supplying water to generate the mixed gas with the source gas between the third cylindrical structure located outside the cylindrical structure, and the water evaporation the said mixed gas delivered from said water vaporization part on the downstream side of the parts is provided with the reforming catalyst layer to flow, located outside of the third cylindrical structure and the third cylindrical structure A reformed gas flow path through which the reformed gas that has passed through the reformed catalyst layer flows between the four cylindrical structures, and at a downstream portion of the flow of the combustion gas flowing through the combustion gas flow path, The flow direction of the combustion gas, the raw material gas flowing through the water evaporation section, the water, the water vapor, and the mixing The flow direction of the combustion gas is opposed to each other, and in the upstream portion of the flow of the combustion gas flowing through the combustion gas flow path, the flow direction of the mixed gas and the reformed gas flowing through the combustion gas flow, the reforming catalyst layer And the flow direction of the raw material gas, the water vapor, and the reformed gas flowing through the reforming catalyst layer and the flow direction of the reformed gas flowing through the reformed gas flow path are opposed to each other. A CO removal catalyst layer for reducing CO in the reformed gas that has passed through the quality gas flow path is provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a first embodiment of the present invention. In FIG. 1, a fuel gas supply unit 1
The fuel gas supplied from the air supply unit 2 and the air supplied from the air supply unit 2 are mixed to form a flame, and the combustion gas generated in the burner 3 is disposed in the burner 3 inside. Hydrogen flows from the exhaust port 5 through the combustion gas passage 4 formed between the one cylindrical structure 100 and the second cylindrical structure 101 adjacent to the outside of the first cylindrical structure 100. Exhausted out of the device. Outside the combustion gas flow path 4, that is, outside the second cylindrical structure 101, a water evaporation unit 8 to which the source gas from the source gas supply unit 6 and the water from the water supply unit 7 are supplied is provided. ing. The mixed gas of the raw material gas and water vapor delivered from the water evaporation unit 8 is between the second cylindrical structure body 101 and the third cylindrical structure body 102 located outside the second cylindrical structure body 101. Is supplied to the reforming catalyst layer 9 filled with the reforming catalyst. Here, the flow direction of the mixed gas or the reformed gas flowing in the reforming catalyst layer 9 is configured to face the flow direction of the combustion gas in the upstream portion of the flow of the combustion gas flowing in the combustion gas flow path 4. Yes. Further, the flow direction of the raw material gas, water, water vapor, and mixed gas flowing in the water evaporation section 8 is configured to face the flow direction of the combustion gas at the downstream portion of the flow of the combustion gas flowing in the combustion gas flow path 4. ing. The reformed gas delivered from the reforming catalyst layer 9 is reformed between the third cylindrical structure 102 and the fourth cylindrical structure 103 located outside the third cylindrical structure 102. After flowing in the gas flow path 15 in the direction opposite to the flow direction of the mixed gas or reformed gas flowing in the reforming catalyst layer 9, the CO removal located outside the water evaporation section 8 and filled with the CO removal catalyst It is supplied to the catalyst layer 10. The gas sent from the CO removal catalyst layer 10 is sent from the hydrogen generator as a product gas containing hydrogen at a high concentration from the product gas outlet 11.

Here, a plurality of protrusions 12 are provided on the outer peripheral surface of the first cylindrical structure 100, and the number of protrusions 12 in the circumferential direction with respect to the first cylindrical structure 100 is the combustion gas in the combustion gas flow path 4. Heat transfer to the reforming catalyst layer 9 is eight in the upstream portion that flows opposite to the flow in the reforming catalyst layer 9 and four in the downstream portion that flows opposite to the flow in the water evaporation portion 8. There are more upstream areas where As the shape of the protrusion 12, the first cylindrical structure 100 is deformed by locally applying pressure from the inside to the outside, and the tip has a substantially conical shape with a rounded shape (generally embossing). And what is called dowel processing. Specifically, the appearance is as shown in FIG. In addition, as shown in FIG. 2B, a round bar having a short length is used as a spacer so that the length direction of the round bar is directed to the outer circumferential surface of the first cylindrical structure 100 in the flow direction of the combustion gas. It can also be set as the structure used by welding or brazing. (Hereinafter, this is also expressed as “projection” including FIG. 2B.) Moreover, the circumferential installation position of the projection 12 may be randomly installed even if the circumference is divided by a substantially equal angle. However, any position may be used as long as the following effects can be obtained. Further, the second cylindrical structure 101 is locally directed from the outer side to the inner side, not on the outer peripheral surface side of the first cylindrical structure 100 but on the inner peripheral surface side of the second cylindrical structure 101. Alternatively, it may be formed by forming a substantially conical shape with a rounded tip that is deformed by applying pressure, or by welding or brazing a round bar having a short length.

  Further, the first cylindrical structure 100, the second cylindrical structure 101, the third cylindrical structure 102, and the fourth cylindrical structure 103 are arranged so that their central axes substantially overlap. Thus, each flow path and catalyst layer are configured.

  In addition, the CO removal catalyst layer 10 is configured as a shift reaction using a shift catalyst, a mixture of oxygen supplied and mixed to perform a selective oxidation reaction using a selective oxidation catalyst, or a combination of these reactions. be able to.

  The reforming catalyst filled in the reforming catalyst layer 9 is made of a noble metal such as Pt, Ru, Rh, Pd, Ni, or the like. As the shift catalyst filled in the CO removal catalyst layer 10, a noble metal such as Pt, Fe—Cr, Cu—Zn, or the like is used. As the selective oxidation catalyst, Pt, Ru, Rh, or the like is used.

  In addition, the flow direction of the raw material gas, water, and mixed gas in the water evaporation section 8, the flow direction of the mixed gas and reformed gas in the reforming catalyst layer 9, and the reformed gas flow in the reformed gas passage 15 Actually, the flow direction may be circulating or meandering depending on the arrangement of spiral rods, spiral pipes, rectifying plates, etc. in each part. 1 shows the direction of a large flow from entering the evaporator 8, the reforming catalyst layer 9, and the reformed gas flow path 15 to exiting. In the water evaporator 8 in FIG. From top to bottom, the reformed gas channel 15 shows from bottom to top.

  In addition, the fuel gas supply unit 1, the air supply unit 2, the raw material gas supply unit 6, and the water supply unit 7 are configured to be able to adjust the flow rate of each supply (fuel gas, air, raw material gas, water), It may be a supply pump (driving means) that can change the discharge flow rate of the supply, and the fluid adjustment is a combination of the supply source of the supply and the supply flow rate adjusting valve provided in the downstream flow path. It may be a mechanism.

  Next, the operation of each part of the hydrogen generator in the above configuration will be described.

In the burner 3 , the fuel gas from the fuel gas supply unit 1 is mixed with the air from the air supply unit 2, and a flame is formed by performing discharge by high voltage, local high temperature (not shown) by a heater, or the like. . The combustion gas flow path formed between the first cylindrical structure 100 and the second cylindrical structure 101 from the tip of the first cylindrical structure 100 is a high-temperature combustion gas generated by the flame. 4 is discharged from the exhaust port 5 to the outside of the hydrogen generator as combustion exhaust gas. The heat of the high-temperature combustion gas is transferred to the water evaporation section 8 and the reforming catalyst layer 9 disposed outside the second cylindrical structure 101. In the water evaporation section 8 heated to high temperature by the heat from the combustion gas, water from the water supply section 7 is evaporated into steam, and the raw material and steam from the raw material gas supply section 6 are mixed and then reformed as a mixed gas. Supply to the catalyst layer 9. The reforming catalyst layer 9 is heated to 600 ° C. to 700 ° C. by the combustion gas, and by supplying a mixed gas of the raw material gas and steam, a steam reforming reaction occurs by the reforming catalyst, and hydrogen or monoxide A reformed gas containing carbon, carbon dioxide, etc. is generated. The reformed gas delivered from the reforming catalyst layer 9 is a flow formed between the third cylindrical structure 102 and the fourth cylindrical structure 103 at the tip of the third cylindrical structure 102. The path flows in a direction opposite to the flow direction in the reforming catalyst layer 9. Thereafter, the reformed gas is supplied to the CO removal catalyst layer 10. In the CO removal catalyst layer 10, CO is removed by a shift reaction using a shift catalyst or a selective oxidation reaction using a selective oxidation catalyst after mixing with oxygen, and a product gas containing a high concentration of hydrogen is generated from the product gas outlet 11. It is sent out of the hydrogen generator.

  Here, in order to improve the efficiency and durability of the hydrogen generator, it is necessary to transmit the heat of the high-temperature combustion gas flowing through the combustion gas passage 4 effectively and uniformly to the reforming catalyst layer 9. The amount of heat transferred from the combustion gas flow path 4 varies depending on the flow velocity of the combustion gas. That is, if the circumferential width of the combustion gas flow path 4 is uneven and there are wide and narrow portions, there is a possibility that the flow velocity of the combustion gas will be different. FIG. 3 shows the result of modeling and numerically analyzing the periphery of the reforming catalyst layer 9 from the combustion gas channel 4 and shows the characteristics (conversion rate) of the combustion gas channel and the reforming catalyst layer. The conversion rate, which is a characteristic of the reforming catalyst layer, indicates the ability to generate hydrogen from the raw material gas. The higher the conversion rate, the greater the amount of heat transferred to the reforming catalyst layer, and the more hydrogen is generated. Is shown. From FIG. 3, it can be seen that the narrower the channel width, the greater the amount of heat transfer to the reforming catalyst layer, and the higher the conversion rate of the reforming catalyst layer. Conversely, if the channel width is wide, the conversion rate is low due to a decrease in the amount of heat transfer, and it can be seen that the characteristics change considerably only by changing the channel width in millimeters. Therefore, if the circumferential width of the combustion gas flow path 4 is not managed in millimeters, a difference occurs in the amount of heat transfer to the reforming catalyst layer 9, and the temperature of the reforming catalyst layer 9 becomes higher or lower depending on the location. I will. The reactivity of the reforming reaction is not linear with respect to the temperature, and the higher the temperature, the smaller the improvement rate of the reactivity. Therefore, if the temperature of the reforming catalyst partially rises, heat will be wasted at that location, and if a certain amount of hydrogen is to be generated, the amount of heating in the burner will increase and reforming will occur. Efficiency will be reduced. Further, if the temperature of the catalyst is excessively high, the catalytic activity due to sintering is lowered, and therefore the durability of the catalyst may be deteriorated. Furthermore, when the temperature of the catalyst is partially increased, the temperature of the second cylindrical structure 101 forming a partition wall between the combustion gas flow path 4 and the reforming catalyst layer 9 can also be uneven in the circumferential direction. The temperature will increase. The material forming the structure of the hydrogen generator is stainless steel having high heat resistance. However, if the temperature is uneven in the circumferential direction in a cylindrical axisymmetric configuration, the stress generated in the structure increases. In particular, since the allowable stress value of the material becomes small in a high temperature state, the occurrence of a high temperature portion with uneven temperature may lead to deterioration of the durability of the structure.

  On the other hand, since the combustion gas flowing through the combustion gas flow path 4 passes through the vicinity of the reforming catalyst layer 9 by applying heat to the reforming catalyst layer 9 side, the temperature is lowered when passing through the vicinity of the water evaporation section 8. Therefore, even if the heat transfer from the combustion gas to the water evaporation section 8 is uneven and the second cylindrical structure 101 is stressed due to the temperature unevenness of the second cylindrical structure 101, the second cylindrical shape Since the temperature of the structure 101 is low, the allowable stress value is high, and even if some stress is generated, the durability of the second cylindrical structure 101 is not deteriorated. Further, since the reforming efficiency of the hydrogen generator is substantially determined by the characteristics of the reforming catalyst layer 9, uneven heat transfer to the water evaporation unit 8 does not affect the reforming efficiency.

  Therefore, in this configuration, in order to define the width of the combustion gas flow path 4, the protrusions 12 are formed on the outer peripheral surface of the first cylindrical structure 100 on the combustion gas flow path 4 side. The upstream portion of the combustion gas flow in the combustion gas passage 4 where the passage width needs to be made uniform with high accuracy is increased, and the downstream portion of the combustion gas flow that has a low temperature and does not require the accuracy of the passage width. Then it is less.

Here, the reason why the larger the number of the circumferential protrusions 12 can make the circumferential width of the combustion gas flow path 4 more uniform will be described. 4 shows a configuration in which three protrusions 12 are arranged in the circumferential direction on the outer peripheral surface of the first cylindrical structure 100 ((a1), (a2)) and a configuration in which eight protrusions are arranged ((b1)). (B2)) It is the figure which compares the structural state of the combustion gas flow path 4 with. In addition, it is the figure which used the round bar as the processus | protrusion 12, and showed the cross section of the cylindrical structure in which the processus | protrusion 12 is provided.

  First, when three projections 12 are used, when the first cylindrical structure 100 and the second cylindrical structure 101 do not deviate, as shown in FIG. Assuming a state in which the cylinders of the first cylindrical structure 100 and the second cylindrical structure 101 are displaced due to some influence during operation of the generator and the combustion gas passage 4 has a minimum width, FIG. (A2). That is, when two adjacent protrusions 12 are in contact with the second cylindrical structure 101, the flow path width between the contacted protrusions 12 is minimized (Da1), and the width of the combustion gas flow path 4 on the opposite side is reduced. Becomes the maximum (Da2). When the number of the protrusions 12 is eight, the first cylindrical structure 100 and the second cylindrical structure 101 are as shown in FIG. 4B1 when there is no deviation, but the deviation is the largest. In this case, as shown in FIG. 4 (b2), the minimum flow path width (Db1) and the reverse maximum flow path width (Db2) are formed. Here, the flow path width is clearly smaller in the case where the number of the protrusions 12 is small, that is, three is smaller than that in the case where the number of the protrusions 12 is eight (Da1 <Db1). (Da2> Db2). For example, when the outer diameter of the first cylindrical structure 100 is 100 mm, the inner diameter of the second cylindrical structure 101 is 106 mm, and the height of the protrusion 12 is 2 mm, Da1 = 1.05 mm, Da2 = 4. 95 mm, Db1 = 1.92 mm, and Db2 = 4.08 mm. That is, the larger the number of protrusions 12, the smaller the difference between the narrow portion and the wide portion even if the passage width is extremely shifted, and the uniformity of the combustion gas passage width is high. Therefore, if as many protrusions as possible are provided in the combustion gas flow path, the uniformity of the flow path width can be improved. However, forming a large number of protrusions results in a process for forming a larger number of protrusions, which increases the manufacturing cost, and the first cylindrical structure 100 and the second cylindrical structure. Since the workability is deteriorated when the 101 is fitted, the work time is required and the manufacturing cost may be increased. Therefore, it is necessary to set the number of protrusions according to the required flow path width accuracy.

  FIG. 5 is a diagram showing where the protrusion is provided in the flow direction of the combustion gas with respect to the required protrusion position in the circumferential direction.

  When the protrusion is viewed from one end of the combustion gas flow channel 4 to the other end of the combustion gas flow channel 4 in parallel to the central axes of the first cylindrical structure 100 and the second cylindrical structure 101 (hereinafter, this Such a view is expressed as “when viewed in the flow direction of the combustion gas”), and when eight protrusions are required in the circumferential direction at the position as shown in FIG. Although all the eight protrusions may be provided for all the protrusions provided in a plurality of stages, other than that, as in the constructions (b2) to (b4), in the combustion gas flow direction. If eight projections are configured as shown in (a) when viewed, the same effect can be obtained. If the first cylindrical structure body 100 and the second cylindrical structure body 101 are made with high roundness, the first cylindrical structure body 100 and the second cylindrical structure body 101 are There is no distortion or change in diameter, and if it is positioned at one position in the flow direction of the combustion gas, it can be positioned with respect to the entire cylindrical structure, and the width of the combustion gas passage is kept constant with respect to the flow direction of the combustion gas. Therefore, if the flow path width is regulated somewhere in the flow direction of the combustion gas, the position of the entire cylindrical structure can be defined. However, if it is not made with high roundness, it is assumed that the cylinder is distorted, so many projections are provided in the circumferential direction at many places in the flow direction of the combustion gas to regulate the flow path width. Otherwise, there is a possibility that the combustion gas passage width at a location where the accuracy of the combustion gas passage width is required cannot be made uniform. Therefore, if the number and arrangement of the protrusions are determined according to the manufacturing accuracy of the cylindrical structure, the manufacturing cost can be reduced while maintaining the performance of the hydrogen generator.

Note that the number of protrusions 12 in the circumferential direction or the number of protrusions 12 when viewed in the flow direction of the combustion gas depends on the size and configuration of the hydrogen generator. The number may be 4 to 10 in the upstream portion of the combustion gas flow and 8 or less in the downstream portion of the combustion gas flow.

(Embodiment 2)
FIG. 6 shows a second embodiment of the present invention. In the first embodiment, the value obtained by subtracting the height of the protrusion 12 from the width dimension of the combustion gas passage 4 is smaller in the upstream portion of the combustion gas flow in the combustion gas passage 4 than in the downstream portion. It has a configuration. That is, the protrusion 12 has a protrusion A13 whose height is Ha at the upstream portion of the combustion gas flow in the combustion gas flow path 4, and a protrusion B14 whose height is the protrusion Hb at the downstream portion of the combustion gas flow. For the combustion gas flow path width D, “D−Ha” <“D−Hb” is satisfied. For example, the height of the protrusion A13 is 2.5 mm and the height of the protrusion B14 is 2 mm with respect to the combustion gas flow path width of 3 mm.

  If this configuration is used, the positional relationship between the first cylindrical structure 100 and the second cylindrical structure 101 is shifted in the upstream portion of the flow of the combustion gas where the flow path width of the combustion gas is desired to be made as uniform as possible. Even if this is the case, the width of the combustion gas passage 4 can be regulated by the presence of the projection A13 having a height of Ha, and the amount of deviation can be kept small. Here, if the protrusion B14 has the same height as the protrusion A13, it is possible to make the combustion gas flow path width more uniform in the entire combustion gas flow path 4, but the height of the protrusion is higher when the protrusion is manufactured. The production cost for manufacturing the product is increased, and the production cost is increased due to deterioration of workability when the first cylindrical structure 100 and the second cylindrical structure 101 are combined. It is preferable that the height of the protrusion is increased only in a portion where the uniformity of the width is required.

  As for the shape of the protrusion 12, in the second embodiment as well, as in the first embodiment, the first cylindrical structure 100 is locally pressurized from the inside to the outside as shown in FIG. The tip is deformed by adding a round shape to a substantially conical shape, or a round bar with a short length is used as a spacer on the outer peripheral surface of the first cylindrical structure 100 in the direction of combustion gas flow. It is good also as a structure welded or brazed so that the length direction may face. Further, the second cylindrical structure 101 is locally directed from the outside to the inside on the inner peripheral surface of the second cylindrical structure 101, not on the outer peripheral surface side of the first cylindrical structure 100. It may be formed by forming a substantially conical shape whose tip is deformed by applying pressure, or by welding or brazing a short bar having a short length.

  The hydrogen generator of the present invention realizes high efficiency and high durability performance in consideration of manufacturability and manufacturing cost in a small device size. For example, the hydrogen generator of a home fuel cell power generator It is useful as an apparatus for supplying product gas.

DESCRIPTION OF SYMBOLS 1 Combustion gas supply part 2 Air supply part 3 Burner 4 Combustion gas flow path 5 Exhaust port 6 Raw material gas supply part 7 Water supply part 8 Water evaporation part 9 Reforming catalyst layer 10 CO removal catalyst layer 11 Product gas outlet 12 Protrusion 13 Protrusion A
14 Protrusion B
15 reformed gas channel 100 first cylindrical structure 101 second cylindrical structure 102 third cylindrical structure 103 fourth cylindrical structure

Claims (8)

A plurality of cylindrical structures each having a different diameter and arranged so that the central axes overlap with each other, and a burner for heating the cylindrical structures, and a first innermost one of the plurality of cylindrical structures. A combustion gas flow path through which combustion gas from the burner flows is formed between the cylindrical structure and the second cylindrical structure located outside the first cylindrical structure, and the second cylinder Between the cylindrical structure and the third cylindrical structure located outside the second cylindrical structure, a steam reforming reaction is performed by supplying a mixed gas of steam and a raw material gas to improve the hydrogen content. A reforming catalyst layer that generates a gaseous gas, and a flow direction of the combustion gas flowing through the combustion gas flow path is opposed to a flowing direction of the mixed gas and the reformed gas flowing through the reforming catalyst layer. A cylindrical hydrogen generator, wherein the interval between the combustion gas flow paths is The projections or spacers for lifting, in the upstream portion and the downstream portion of the flow of the combustion gas flowing through the combustion gas flow passage, a plurality, the outer peripheral surface of the first cylindrical structure or said second cylindrical provided on the inner peripheral surface of the structure, the number of the plurality of the protrusions or spacers, said upstream portion is a hydrogen generating apparatus, characterized in that more than the downstream portion. The number of the plurality of protrusions or spacers is the upstream portion of the flow of the combustion gas flowing through the combustion gas flow path in the number per unit area of the first cylindrical structure or the second cylindrical structure. The hydrogen generator according to claim 1, wherein there are more than the downstream part. The number of the plurality of protrusions or spacers is the number in the circumferential direction of the first cylindrical structure or the second cylindrical structure, and the upstream portion of the flow of the combustion gas flowing through the combustion gas flow path is The hydrogen generator according to claim 1, wherein the hydrogen generator is more than the downstream portion. The number of the plurality of protrusions or spacers is such that the protrusions or spacers flow from one end of the combustion gas flow path in parallel to the central axes of the first cylindrical structure and the second cylindrical structure. The number of the protrusions or spacers that can be seen when viewed to the other end of the path, the upstream portion of the flow of the combustion gas flowing through the combustion gas flow path is more than the downstream portion. The hydrogen generator of any one of Claims. The number of the projections or spacers in the circumferential direction, or the projections or spacers from one end of the combustion gas flow path parallel to the central axis of the first cylindrical structure and the second cylindrical structure It claims the number of said protrusions or spacers seen when viewed to the other end of the flow path, characterized in that said upstream portion of the flow of the combustion gas flowing through the combustion gas flow passage is 10 from 4 3 Or the hydrogen generator of 4. A plurality of cylindrical structures each having a different diameter and arranged so that the central axes overlap with each other, and a burner for heating the cylindrical structures, and a first innermost one of the plurality of cylindrical structures. A combustion gas flow path through which combustion gas from the burner flows is formed between the cylindrical structure and the second cylindrical structure located outside the first cylindrical structure, and the second cylinder Between the cylindrical structure and the third cylindrical structure located outside the second cylindrical structure, a steam reforming reaction is performed by supplying a mixed gas of steam and a raw material gas to improve the hydrogen content. A reforming catalyst layer that generates a gaseous gas, and a flow direction of the combustion gas flowing through the combustion gas flow path is opposed to a flowing direction of the mixed gas and the reformed gas flowing through the reforming catalyst layer. A cylindrical hydrogen generator, wherein the interval between the combustion gas flow paths is The projections or spacers for lifting, in the upstream portion and the downstream portion of the flow of the combustion gas flowing through the combustion gas flow passage, a plurality, the outer peripheral surface of the first cylindrical structure or said second cylindrical provided on the inner peripheral surface of the structure, minus the plurality of height of the protrusions or spacers from the dimension of the interval of the combustion gas flow path, said upstream portion being smaller than said downstream portion of hydrogen Generator. The protrusion or spacer is formed by pressing the first cylindrical structure or the second cylindrical structure from one side and deforming it into a substantially conical shape, or by using a short round bar as the combustion gas. The hydrogen generator according to any one of claims 1 to 6, wherein the hydrogen generator is arranged so that a length direction of the round bar faces a flow direction of the combustion gas flowing through the flow path. The burner is provided inside the first cylindrical structure, and between the second cylindrical structure and a third cylindrical structure located outside the second cylindrical structure. the the water evaporation portion where the supply of water to generate the steam to generate the mixed gas of the raw material gas, the mixed gas sent from the water evaporation unit downstream of the water evaporation unit flows The reforming catalyst layer is provided, and the modified catalyst layer that has passed through the reforming catalyst layer is interposed between the third cylindrical structure and a fourth cylindrical structure located outside the third cylindrical structure. A reformed gas flow path through which a quality gas flows, and at a downstream portion of the flow of the combustion gas flowing through the combustion gas flow path, the flow direction of the combustion gas, the raw material gas flowing through the water evaporation section, and the water The combustion gas flowing in the combustion gas flow path in which the flow direction of the water vapor and the mixed gas oppose each other In the upstream portion of the flow of gas, the flow of the combustion gas and the flow direction of the mixed gas and the reformed gas flowing through the reforming catalyst layer are opposed to each other, and the raw material gas flowing through the reforming catalyst layer and the The direction in which the water vapor and the reformed gas flow and the direction in which the reformed gas flowing through the reformed gas flow path face each other to reduce CO in the reformed gas that has passed through the reformed gas flow path. The hydrogen generator according to any one of claims 1 to 7, further comprising a CO removal catalyst layer.

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