JP2011006279A - Hydrogen generation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen generation apparatus capable of being operated stably over a long period of time by preventing a partition wall covering a part of an evaporator from being broken, even if there is thermal expansion and contraction by repeated operation and stopping.SOLUTION: In a heater (inner cylinder 1), combustion gas is generated by burning a gaseous mixture of fuel and air in a combustion part 4. An evaporator 6 generates a gaseous mixture by heating a raw material and water using the combustion gas in a first evaporating part 6a, and unevaporated water is evaporated at a partition wall 11 which covers a second evaporating part 6b arranged at the lower side continuously following the first evaporating part 6a. In a reformer 8, hydrogen-containing gas is generated by passing the gaseous mixture from the second evaporating part 6b through a reforming catalyst which is heated by the combustion gas. In a carbon monoxide removing part 10, the amount of carbon monoxide in the hydrogen containing gas generated by the reformer 8 is reduced and hydrogen is generated. Since the partition wall 11 has a partition wall welding part 11b adhered to the second evaporating part 6b and a partition wall sliding part 11c which is press-fitted to the second evaporating part 6b and carries out thermal expansion moving, the hydrogen generation apparatus can be operated stably in preventing the partition wall 11 from being broken as opposed to thermal expansion and contraction of the hydrogen generation apparatus.

Description

  The present invention provides a fuel cell system in which a reformer that generates a hydrogen-containing gas, a transformer and a selective oxidizer that reduce the concentration of carbon monoxide, and a heater that heats them are integrated. The present invention relates to a hydrogen generation apparatus.

  Conventionally, a fuel cell system capable of small-scale high-efficiency power generation can easily realize a high energy utilization efficiency because it is easy to construct a system for using thermal energy generated during power generation operation. Development as a distributed power generation system is underway.

  In a fuel cell system, during a power generation operation, a hydrogen-containing gas containing hydrogen and an oxygen-containing gas containing oxygen are contained in a fuel cell stack (hereinafter simply referred to as “fuel cell”) disposed as a main body of the power generation unit. Each supplied.

  Then, in the fuel cell, hydrogen contained in the supplied hydrogen-containing gas and oxygen contained in the oxygen-containing gas are used, and a predetermined electrochemical reaction proceeds. As the predetermined electrochemical reaction proceeds, chemical energy of hydrogen and oxygen is directly converted into electrical energy in the fuel cell. As a result, the fuel cell system outputs power toward the load.

  Now, the supply means of the hydrogen-containing gas required at the time of power generation operation of the fuel cell system has not been maintained as a normal infrastructure.

  Therefore, in the conventional fuel cell system, for example, steam at a temperature of 600 ° C. to 700 ° C. using a source gas such as city gas or LPG obtained from an existing fossil raw material infrastructure and water vapor generated by a water evaporator. In many cases, a reformer that advances a reforming reaction to generate a hydrogen-containing gas is provided together with a fuel cell.

  On the other hand, the hydrogen-containing gas obtained by the steam reforming reaction usually contains a large amount of carbon monoxide and carbon dioxide derived from the raw material gas. Therefore, in the conventional fuel cell system, in order to reduce the concentration of carbon monoxide contained in the hydrogen-containing gas generated in the reformer, a carbon monoxide removal unit is provided downstream of the reformer. .

  The breakdown is selected from a transformer that reduces the concentration of carbon monoxide by lowering the temperature of the hydrogen-containing gas and advancing the water gas shift reaction at a temperature of 200 ° C. to 350 ° C., and a temperature of 100 ° C. to 150 ° C. A selective oxidizer that further reduces the concentration of carbon monoxide by advancing the oxidation reaction is often provided along with the fuel cell and the reformer.

  Here, the conventional fuel cell system is provided with a hydrogen generation apparatus including these reformers, a transformer as a carbon monoxide removing unit, and a selective oxidizer. Each of these reformer, shifter, and selective oxidizer is provided with a catalyst suitable for each chemical reaction for proceeding with each of the steam reforming reaction, the water gas shift reaction, and the selective oxidation reaction. ing. For example, a Ru catalyst or a Ni catalyst is disposed in the reformer. In addition, a Cu—Zn catalyst and a noble metal catalyst are disposed in the transformer. The selective oxidizer is provided with a Ru catalyst or the like.

  By the way, in the hydrogen generator having the above-described configuration, it is generally necessary to maintain the temperature of each reactor at an optimum temperature in order to appropriately proceed the chemical reaction in each reactor. In view of this, there has been proposed a hydrogen generator in which each of a reformer, a water evaporator, a transformer, and a selective oxidizer is disposed in a concentric cylindrical shape around a heater. As such a hydrogen generator, Patent Document 1 and the like have been proposed, and an example thereof is shown in FIG.

  3 includes a cylinder 3 having an inner cylinder 1 and an outer cylinder 2, a combustion gas passage 5 provided along the inner periphery of the inner cylinder 1 and through which combustion gas generated in the combustion section 4 flows, Vaporization arranged along the inner cylinder 1 between the cylinder 1 and the outer cylinder 2 to supply the source gas and water, evaporate water by heating from the combustion gas flow path 5, and heat the source gas A raw material gas that is disposed between the inner cylinder 1 and the outer cylinder 2 and is provided with the reforming catalyst 7 and is supplied from the evaporator 6, and the evaporator 6 (first and second evaporators 6 a and 6 b). The reformer 8 is formed between the inner cylinder 1 and the outer cylinder 2 and is provided with a carbon monoxide removal catalyst 9 and is reformed while reforming the steam 8 to produce a reformed gas containing hydrogen by a steam reforming reaction. A hydrogen generator comprising a carbon monoxide removing unit 10 for removing carbon monoxide in the reformed gas supplied from the mass device 8. .

  In the hydrogen generator, the evaporator 6 is disposed below the first evaporator 6a, which is disposed at a position where heat exchange with the carbon monoxide remover 10 is possible, and continuously below the first evaporator 6a. The first evaporating unit 6a is formed from a second evaporating unit 6b that evaporates water that has not been evaporated, and a partition wall 11 is provided surrounding the side and lower side of the second evaporating unit 6b, and an opening 12 is formed above the partition wall 11. A guide path 13 is formed between the partition wall 11, the second evaporator 6 b, and the partition wall 11 where the water vapor evaporated by the first evaporator 6 a and the water vapor evaporated by the second evaporator 6 b merge. A configuration is formed by forming a mixed gas flow path 14 that is supplied from the evaporator 6 through the induction path 13 and passed through the opening portion 12 between the gasifier 8 and is supplied to the reformer 8 by flowing the raw material gas and water vapor. is there.

  As a result, when the amount of raw material gas and the amount of water supplied to the evaporator 6 are large and the water does not completely evaporate in the first evaporation unit 6a of the evaporator 6, the unevaporated water is converted into the second evaporation unit 6b. The water vapor evaporated by the first evaporator 6a and the water vapor evaporated by the second evaporator 6b are merged in the induction path 13, and the steam is supplied from the opening 12 to the reformer 8 through the mixed gas flow path 14. The non-evaporated water flowing into the second evaporation unit 6b from the first evaporation unit 6a stays in the lower part of the partition wall 11 and prevents the unevaporated water from flowing into the reformer 8.

  Further, the amount of raw material gas and water supplied to the evaporator 6 are small, and the water vapor evaporated in the first evaporator 6a of the evaporator 6 is further heated in the second evaporator 6b to become high-temperature superheated steam. In this case, the low-temperature steam in the first evaporator 6a and the high-temperature superheated steam in the second evaporator 6b are merged in the induction path 13 to become appropriate-temperature steam, and the high-temperature steam is prevented from flowing into the reformer 8. It is out.

  Further, when the raw material gas and water vapor flowing from the evaporator 6 through the induction path 13 pass through the opening 12, the flow velocity is increased to promote the mixing of the raw material gas and the water vapor, and the mixed gas as a uniformly mixed gas mixture A hydrogen generator that can be supplied from the flow path 14 to the reformer 8 has been proposed.

JP 2008-63171 A

  However, in the hydrogen generator shown in FIG. 3, the evaporator 6 is continuously connected to the first evaporator 6a and the first evaporator 6a, which are arranged at positions where heat exchange with the carbon monoxide remover 10 is possible. Then, a partition wall 11 is provided which is formed from a second evaporation section 6b which is disposed below the first evaporation section 6a and evaporates water which has not been evaporated by the first evaporation section 6a. In addition, the opening 12 at the upper part of the partition wall 11, the induction path 13 where the water vapor evaporated by the first evaporation unit 6 a and the water vapor evaporated by the second evaporation unit 6 b join between the second evaporation unit 6 b and the partition wall 11, Between the opening 12 and the reformer 8, a mixed gas flow path 14 that is supplied from the evaporator 6 through the induction path 13 and that passes through the opening 12 and feeds the raw material gas and water vapor to the reformer 8 is provided. In order to form, the space of the 2nd evaporation part 6b needs to be comprised with a welding structure. That.

  In the operating state of the hydrogen generator, the partition wall 11 has a temperature of about 300 ° C. with respect to the temperature of the second evaporator 6b of about 130 ° C. Therefore, the thermal expansion dimension of the partition wall 11 is the amount of thermal expansion of the second evaporator 6b. However, thermal deformation is constrained at the weld fixing portions above and below the partition wall 11, and the corners under the partition wall 11 and the portion where the partition wall 11 is welded to the inner cylinder 1 (partition weld portion 11b) Thermal stress was generated at the time, and there was concern about breakage due to thermal expansion and contraction of repeated operation and stop.

  The present invention solves the above-mentioned conventional problems, and in an evaporator provided in a hydrogen generator and a partition wall disposed so as to cover a part of the evaporator, thermal expansion and contraction of repeated operation and stop An object of the present invention is to provide a structure that reduces the thermal stress caused by the above.

  In order to achieve the above object, a hydrogen generator according to claim 1 of the present invention includes a heater that generates a combustion gas by burning a mixture of fuel and air for combustion, and a combustion that is generated by the heater. A first evaporator part of an annular evaporator that heats the raw material and water by gas to generate a mixture of the raw material and water vapor, and a partition wall arranged continuously below the first evaporator part to evaporate non-evaporated water A second evaporator of the evaporator covered with an annular reformer that generates a hydrogen-containing gas by passing a reformed catalyst heated by a combustion gas through an air-fuel mixture supplied via the second evaporator; A carbon monoxide removal unit containing a removal catalyst for reducing carbon monoxide in the hydrogen-containing gas produced by the reformer, and a partition wall on one side fixed to the second evaporation unit, and the other side It has a contact portion that is press-fitted into the second evaporation section and moves by thermal expansion.

  The invention described in claim 2 is characterized in that, in the hydrogen generator of claim 1, the partition walls are made of a ferritic stainless material, and the evaporator in contact with the partition walls is made of an austenitic stainless material.

  According to the said structure, even if the thermal expansion contraction of a repetition driving | operation and a stop arises in an apparatus, the movement accompanying a relative heat is attained between a partition and the press-fitted 2nd evaporation part, 2nd Since the thermal stress generated in the portion where the evaporation section is fixed to the partition wall is reduced, there is no risk of damage to the structure, the life of the hydrogen generator can be extended, and the number of welded portions of the partition wall can be reduced. Therefore, it is possible to provide a highly practical hydrogen generator.

  According to the present invention, in the evaporator provided in the hydrogen generator, and the partition wall disposed so as to cover a part of the evaporator, the thermal stress due to the thermal expansion and contraction of the repeated operation and stop is reduced, There is an effect that it is possible to provide a highly practical hydrogen generator, such as extending the life of the apparatus and reducing the number of welded portions between the evaporator and the partition wall, thereby facilitating assembly.

Sectional drawing which shows the outline of the hydrogen generator which concerns on embodiment of this invention The fragmentary sectional view which expanded the partition neighborhood concerning this embodiment Sectional drawing which shows the outline of the conventional hydrogen generator

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an outline of a hydrogen generator according to an embodiment of the present invention, and FIG. 2 is an enlarged partial cross-sectional view of the vicinity of a partition wall. Hereinafter, although embodiment of this invention is described, this invention is not limited by this embodiment. In addition, components having equivalent functions corresponding to the components described in FIG.

  FIG. 1 is a diagram showing an example of the present embodiment. A cylindrical body 3 serving as a casing of the apparatus is formed by arranging a cylindrical inner cylinder 1 and an outer cylinder 2 in a concentric cylindrical shape with the axial direction vertical. It is. In this cylindrical body 3, the upper and lower ends of the cylindrical space between the inner cylinder 1 and the outer cylinder 2 are closed. A combustion unit 4 made of a burner is provided at the center of the inner periphery of the inner cylinder 1 as a heater, and combustion air is blown from a combustion fan 31. A combustion gas flow path 5 is formed between the combustion section 4 and the inner cylinder 1 along the inner periphery of the inner cylinder 1, and the combustion gas burned in the combustion section 4 flows along the combustion gas flow path 5. It is like that.

  Between the inner cylinder 1 and the outer cylinder 2 in the upper part of the cylindrical space of the cylindrical body 3, an evaporator 6 is provided on the inner cylinder 1 side, and a carbon monoxide removing unit 10 is provided on the outer cylinder 2 side in a concentric cylindrical shape. It is. The evaporator 6 is formed as a cylindrical space along the outer surface of the inner cylinder 1, and the carbon monoxide removing unit 10 is formed in a cylindrical shape in contact with the outer surface of the evaporator 6. A raw material gas supply unit 25 and a water supply unit 26 are connected to the upper end of the evaporator 6. A reformer 8 is provided below the lower end of the evaporator 6. The reformer 8 is formed in a cylindrical shape in contact with the inner surface of the inner cylinder 1.

  The evaporator 6 is formed by an upper first evaporator 6a and a lower second evaporator 6b. The upper first evaporator 6a is in contact with the carbon monoxide remover 10 so that the first evaporator 6a and the carbon monoxide remover 10 can exchange heat with each other, and the lower second evaporator 6b. Is positioned below the lower end of the carbon monoxide removal unit 10. In the cylindrical space of the evaporator 6, a spiral guide body 33 is attached over the entire length from the upper end of the first evaporator 6a to the lower end of the second evaporator 6b. The guide body 33 is formed with a diameter equal to the space thickness of the evaporator 6, so that the cylindrical space of the evaporator 6 is partitioned by a spiral guide body 33 and spirals around the outer periphery of the inner cylinder 1. It is formed as a flow path.

  The first evaporator 6 a is surrounded by the inner cylinder 1 and the carbon monoxide removing unit 10, but the second evaporator 6 b is surrounded by the inner cylinder 1 and the partition wall 11. As shown in FIG. 2, the partition wall 11 is formed from the side surface to the bottom surface of the second evaporator 6 b, and the upper end of the partition wall 11 that has been subjected to widening is press-fitted into the side surface of the second evaporator 6 b. The inner peripheral end of the lower part of each is connected to the outer peripheral surface of the inner cylinder 1. An opening 12 that is a notch is opened at the upper end of the side of the partition wall 11.

  Further, a partition plate 35 is provided on the inner side of the partition wall 11 so as to extend flush with the outer surface of the first evaporation unit 6 a (also the inner surface of the carbon monoxide removal unit 10), and between the partition wall 11 and the inner cylinder 1. The space in the partition wall 11 is partitioned into the second evaporation section 6b on the inside and the guide path 13 on the outside. The guide path 13 is formed as a cylindrical space surrounding the second evaporator 6 b, and the partition plate 35 has communication ports 36 opened at a plurality of upper and lower positions.

  Between the upper end of the outer peripheral surface of the reformer 8 and the lower surface of the carbon monoxide removal unit 10, a cylindrical heat exchange plate 38 parallel to the inner cylinder 1 and the outer cylinder 2 is attached outside the partition wall 11. The mixed gas flow path 14 is formed between the heat exchange plate 38 and the partition wall 11, and the reformed gas flow path 16 is formed between the heat exchange plate 38 and the outer cylinder 2. The mixed gas channel 14 is a channel that connects the opening 12 that is a notch of the partition wall 11 and the inlet 39 at the upper end of the reformer 8, and the reformed gas channel 16 is an outer periphery of the reformer 8. It is a flow path that connects the outlet 40 provided in the lower part and the inlet 41 at the lower end of the carbon monoxide removing unit 10.

  The reformer 8 is formed by filling the reforming catalyst 7. The carbon monoxide removing unit 10 includes two converters: a converter 10a charged with a CO conversion catalyst 9a as a carbon monoxide removal catalyst 9 and a selective oxidizer 10b charged with a CO selective oxidation catalyst 9b as a carbon monoxide removal catalyst 9. It is formed in a step configuration (see FIG. 1). The transformer 10a is disposed on the lower side and the selective oxidizer 10b is disposed on the upper side so that the transformer 10a is the front stage and the selective oxidizer 10b is the rear stage in the flow direction of the reformed gas. Air is supplied from the air supply unit 28 between the containers 10b. The outlet of the upper end of the carbon monoxide removing unit 10 is connected to the fuel cell 18.

  In the hydrogen generation apparatus formed as described above, the evaporator 6 is heated by the combustion gas flowing through the combustion gas flow path 5, and after the operation of the hydrogen generation apparatus is started, the carbon monoxide removal unit 10 The reaction heat of the CO shift reaction or the CO selective oxidation reaction is transferred and heated. When the raw material gas supply unit 25 supplies hydrocarbon-based raw material gas such as city gas or LPG, and the water supply unit 26 supplies water to the evaporator 6, the raw material gas and water are evaporated. 6 is heated while passing through the second evaporator 6b from the first evaporator 6a, and the water evaporates to become water vapor. The heated mixed gas of raw material gas and water vapor passes through the communication port 36 of the partition plate 35 and flows into the guide path 13, and further passes through the opening portion 12 which is a notch of the partition wall 11 and passes through the mixed gas flow path. 14 flows in.

  Next, the mixed gas of the raw material gas and the steam flows through the mixed gas passage 14 and flows into the reformer 8 from the inlet 39, and the raw material gas and the steam undergo a steam reforming reaction by the catalytic action of the reforming catalyst 7. Thus, a hydrogen-rich reformed gas is generated. Since the steam reforming reaction is an endothermic reaction, the reformer 8 is heated by the combustion gas flowing through the combustion gas flow path 5.

  Here, in order to properly perform the steam reforming reaction in the reformer 8, in addition to the temperature of the reforming catalyst of the reformer 8 being appropriate, the raw material gas supplied to the reformer 8 and It is necessary that the water vapor is sufficiently mixed. Therefore, in the present embodiment, as described above, the spiral guide body 33 extending from the upper end of the first evaporator 6a to the lower end of the second evaporator 6b is provided in the cylindrical space of the evaporator 6 to evaporate. The vessel 6 is formed as a spiral flow path, and the flow path through which the raw material gas and the water vapor pass is lengthened so that the raw material gas and the water vapor are sufficiently mixed. The mixed gas is supplied to the reformer 8.

  Furthermore, after the raw material gas and water vapor are flowed into the induction path 13 from the first evaporation section 6a and the second evaporation section 6b, they are discharged to the mixed gas flow path 14 through the opening 12 which is a notch. When the raw material gas or water vapor passes from the guide path 13 to the opening 12 which is a notch, the flow channel is throttled and the flow velocity is increased, so that the water vapor and the raw material gas are sufficiently mixed. In other words, the reformer 8 can be supplied as a uniform mixed gas from the mixed gas flow path 14.

  The reformed gas generated in the reformer 8 flows out from the outlet 40 at the lower end of the reformer 8 to the reformed gas channel 16 and is reformed when rising in the reformed gas channel 16. Heat exchange is performed with the gas generator 8 and heat exchange with the mixed gas flowing through the mixed gas flow path 14 through the heat exchange plate 38, and the reformed gas is lowered to a temperature suitable for the reaction in the carbon monoxide removal unit 10.

  Next, the reformed gas flows into the converter 10a of the carbon monoxide removing unit 10 from the inlet 41 at the lower end, and the carbon monoxide in the reformed gas is removed by the CO shift reaction. Here, the temperature suitable for the CO shift reaction in the shift converter 10a is 200 to 250 ° C., where the temperature near the inlet 41 is lower than the temperature of the reformed gas flowing out from the reformer 8, as described above. When the reformed gas flows through the reformed gas channel 16, the temperature is lowered to 200 to 250 ° C. by exchanging heat with the mixed gas in the mixed gas channel 14. The reformed gas from which carbon monoxide has been removed by the converter 10a further flows into the selective oxidizer 10b, and oxygen in the air supplied from the air supply unit 28 by the action of the CO selective oxidation catalyst 9b and a CO selective oxidation reaction. Thus, carbon monoxide in the reformed gas is further removed.

  The reformed gas from which carbon monoxide has been removed by the carbon monoxide removing unit 10 in this way flows out of the carbon monoxide removing unit 10 and is supplied to the fuel cell 18. In the fuel cell 18, power generation is performed using hydrogen in the reformed gas supplied in this way from the hydrogen generator and an oxidizing gas containing oxygen such as air.

  Here, when power is generated in the fuel cell 18 using the reformed gas supplied from the hydrogen generator as described above, the reaction load of the fuel cell 18, that is, the consumption of the reformed gas is changed. The amount of source gas supplied to the evaporator 6 from the source gas supply unit 25 and the water supply unit 26 and the amount of water vary. As described above, when the amount of raw material gas or water supplied to the evaporator 6 reaches the maximum amount, the water is not completely evaporated in the evaporator 6, and the reformer remains as water. 8, the reformer 8 is cooled with water, the catalyst temperature is lowered, the temperature of the reformed gas exiting the reformer 8 is also lowered, and the temperature of the carbon monoxide removal unit 10 is changed to the CO shift reaction. May be lower than suitable temperature. Conversely, when the amount of raw material gas or water supplied to the evaporator 6 becomes the minimum amount, the water is superheated in the evaporator 6 to become high-temperature superheated steam. The catalyst temperature becomes too high, and the carbon monoxide removing unit 10 also becomes a catalyst temperature that is not suitable for the transformation temperature. The reforming reaction capacity in the reformer 8 and the carbon monoxide in the carbon monoxide removing unit 10 are reduced. The removal capability will be reduced.

  Therefore, when the evaporator 6 of the hydrogen generator is configured as described above and the amount of raw material gas or water supplied to the evaporator 6 is large, the water is not discharged in the first evaporator 6 a of the evaporator 6. Although it is evaporation, the flow path of the first evaporation part 6a is formed in a spiral flow path by the guide body 33 so as to secure the heat transfer area from the combustion gas flow path 5 and the carbon monoxide removal part 10. Therefore, the water becomes two phases, that is, a non-evaporated water phase and a vapor phase of evaporated water vapor, and flows in the spiral flow path of the first evaporation section 6a in this two-phase state. At this time, unevaporated water flows down along the upper surface of the guide body 33, and water vapor flows along the space portion of the spiral flow path between the guide bodies 33, and the first evaporation is performed in a two-phase flow state. It flows into the 2nd evaporation part 6b from part 6a. Thus, since the two-phase flow flows from the first evaporator 6a to the second evaporator 6b, the temperature of the water vapor coming out of the first evaporator 6a is about 100 ° C.

  Of the two-phase flow that flows from the first evaporator 6a to the second evaporator 6b, the water that has not evaporated evaporates by heating from the combustion gas flow path 5 in the second evaporator 6b and becomes water vapor. At this time, the evaporation amount of water varies, and the water droplets may not completely evaporate even in the second evaporation part 6b. However, even if there is unevaporated water in this way, the water remains in the partition wall bottom part 11a below the partition wall 11. And water does not flow into the reformer 8.

  Of the two-phase flow that has flowed from the first evaporator 6a to the second evaporator 6b, the water vapor is superheated by the second evaporator 6b to become superheated steam at 150 ° C. or higher, but from the first evaporator 6a. The water vapor that flows directly into the induction path 13 through the communication port 36, the water vapor that evaporates at the second evaporation unit 6b and flows into the induction path 13 through the communication port 36, and is overheated and communicated with the second evaporation unit 6b. This superheated steam flowing into the induction path 13 through the mouth 36 is mixed in the induction path 13 and becomes steam at an appropriate temperature of about 150 ° C. and passes through the opening 12 which is a notch.

  The raw material gas and water vapor that have flowed into the induction path 13 from the first evaporator 6a and the second evaporator 6b are mixed when passing through the opening 12 that is a notch, and are sent to the mixed gas flow path 14 as a mixed gas. However, the mixed gas flowing through the mixed gas flow path 14 is heated by heat exchange with the reformed gas flowing through the reformed gas flow path 16. The mixed gas flowing in the mixed gas flow path 14 is also heat-exchanged with the gas in the induction path 13 through the partition wall 11, but when the amount of water supplied is large, the temperature in the induction path 13 is lower than in the normal case. The heating temperature of the gas is also slightly lower than usual, and is supplied to the reformer 8 as a mixed gas having a temperature of about 350 ° C.

  When the temperature of the mixed gas supplied to the reformer 8 is about 350 ° C., the temperature of the reformed gas generated in the reformer 8 and exiting from the outlet 40 of the reformer 8 is about 400 ° C. When the reformed gas flows through the reformed gas channel 16, the temperature is lowered by the heat exchange with the mixed gas in the mixed gas channel 14, and the temperature is reduced to about 200 ° C. The carbon monoxide removal unit 10 To be supplied.

  On the other hand, when the amount of source gas supplied to the evaporator 6 and the amount of water are small, all of the water is evaporated while passing through the first evaporator 6a, but this water vapor is superheated in the first evaporator 6a. Therefore, the heat transfer area of the spiral flow path of the first evaporator 6a is set so as not to become superheated steam. In order to evaporate non-evaporated water when the supply amount of water is large as described above, the second evaporation unit 6b is provided after the first evaporation unit 6a, so that the first evaporation unit 6a has evaporated. When the water vapor flows into the second evaporator 6b, the water vapor is superheated by heating from the combustion gas flow path 5 to become superheated steam, and this superheated steam becomes a high temperature of about 300 ° C. In this way, the water vapor becomes high-temperature superheated steam in the second evaporator 6b and flows into the guide path 13 from the communication port 36, but directly flows into the guide path 13 through the communication port 36 from the first evaporator 6a. The steam having a temperature of about 100 ° C. and the superheated steam are mixed in the induction path 13 to be steam having an appropriate temperature of about 150 ° C. and pass through the opening 12 which is a notch.

  The raw material gas or water vapor that has flowed into the induction path 13 from the first evaporation section 6a or the second evaporation section 6b passes through the opening 12 that is a notch and is sent to the mixed gas flow path 14 as a mixed gas. The mixed gas flowing in the mixed gas flow path 14 is heated by heat exchange with the reformed gas flowing in the reformed gas flow path 16, but is also heat exchanged with the gas in the induction path 13 through the partition wall 11 to supply water. When the amount is small, the temperature in the guide path 13 is higher than usual, so the temperature of the mixed gas is slightly higher than usual, and is supplied to the reformer 8 as a mixed gas having a temperature of about 400 ° C. The When the temperature of the mixed gas supplied to the reformer 8 is about 400 ° C., the temperature of the reformed gas generated in the reformer 8 and exiting from the outlet 40 of the reformer 8 is about 450 ° C. When the reformed gas flows through the reformed gas channel 16, the temperature is lowered by the heat exchange with the mixed gas in the mixed gas channel 14 to reach a temperature of about 220 ° C., and the carbon monoxide removing unit 10 To be supplied.

  As described above, even if the amount of raw material gas and the amount of water supplied to the evaporator 6 fluctuate, the temperature of the mixed gas supplied to the reformer 8 is the same as when the supply amount of water is the maximum amount. The temperature difference between the partition plate 35 and the partition wall 11 is 250 ° C. because the temperature is about 350 ° C. and the minimum amount is about 400 ° C., which is within the temperature range suitable for the steam reforming catalyst. One partition welded part 11b is fixed to the second evaporation part 6b, and the other partition sliding part 11c is provided with a contact part that thermally expands and moves with respect to the second evaporation part 6b, thereby restraining expansion deformation due to heating. Even if there is a thermal expansion / shrinkage of repeated operation and stop, relative movement between the partition sliding portion 11c and the second evaporation portion 6b becomes possible, and the heat of the welded portion and the lower corner portion of the partition welded portion 11b becomes possible. Stress is reduced and there is no risk of damage to the structure.

  The fixing method between the partition wall welded portion 11b and the second evaporation portion 6b may be caulking bonding, diffusion bonding, or rivet bonding.

  Further, by providing at least one notch on the side where the partition sliding portion 11c is inserted, the tightening stress after the partition sliding portion 11c is pressed into the second evaporation portion 6b is reduced, and the partition sliding is performed. The possibility of causing wear damage due to relative movement between the portion 11c and the second evaporation portion 6b is also eliminated. Accordingly, the mixed gas flow path can be configured without welding by press-fitting the partition sliding portion 11c, and the expansion deformation due to heating is not restrained during the operation of the hydrogen generator, and the thermal expansion and contraction between the repeated operation and the stop is performed. Even if it exists, relative movement between the partition sliding portion 11c and the second evaporation portion 6b is possible, and thermal stresses at the partition welded portion 11b and the lower corners of the partition 11 can be reduced.

  Therefore, it is possible to provide a highly practical hydrogen generator such that the life of the hydrogen generator can be extended and the number of welding points can be reduced, so that the assembly of the second evaporation section 6b is facilitated.

  The present invention has a structure for reducing thermal stress due to thermal expansion and contraction of repeated operation and stop in an evaporator provided in a hydrogen generator and a partition wall disposed so as to cover a part of the evaporator. It is possible to provide a highly practical device such as a longer life and a reduced number of welds between the evaporator and the partition wall, which facilitates assembly, and is useful as a hydrogen generator provided in a fuel cell system.

DESCRIPTION OF SYMBOLS 1 Inner cylinder 2 Outer cylinder 3 Cylinder 4 Combustion part 5 Combustion gas flow path 6 Evaporator 6a 1st evaporation part 6b 2nd evaporation part 7 Reforming catalyst 8 Reformer 9 Carbon monoxide removal catalyst 9a CO shift catalyst 9b CO Selective oxidation catalyst 10 Carbon monoxide removal part 10a Transformer 10b Selective oxidizer 11 Partition 11a Partition bottom 11b Partition weld 11c Partition sliding part 12 Opening 13 Induction path 14 Mixed gas path 16 Reformed gas path 18 Fuel cell 25 Material gas supply unit 26 Water supply unit 28 Air supply unit 31 Combustion fan 33 Guide body 35 Partition plate 36 Communication port 38 Heat exchange plate 39, 41 Inlet port 40 Outlet port

Claims (2)

A heater that burns a fuel / air mixture for combustion to generate combustion gas, and an annular evaporation that heats raw material and water by the combustion gas generated by the heater to generate a mixture of raw material and water vapor A first evaporation section of the vessel, a second evaporation section of the evaporator which is arranged continuously below the first evaporation section and is covered with a partition wall for evaporating non-evaporated water, and the second evaporation section An annular reformer that produces a hydrogen-containing gas by passing the reformed catalyst heated by the combustion gas through the supplied gas mixture, and carbon monoxide in the hydrogen-containing gas produced by the reformer And a carbon monoxide removal unit with a built-in removal catalyst for reducing
The hydrogen generating apparatus according to claim 1, wherein the partition has a part fixed to the second evaporation part on one side and a contact part that is press-fitted into the second evaporation part and thermally expands and moves on the other side.   2. The hydrogen generation apparatus according to claim 1, wherein the partition wall is made of a ferritic stainless material, and the evaporator in contact with the partition wall is made of an austenitic stainless material.

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