JP2015109218A - Hot module for solid oxide type fuel cell and solid oxide type fuel cell system including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means capable of improving the service durability of components in a hot module for solid oxide type fuel cell.SOLUTION: The hot module for solid oxide type fuel cell includes: a hydrodesulfurization unit 2 that removes sulfur compounds from raw material; a reformer 4 that reforms the raw material supplied from the hydrodesulfurization unit to generate a hydrogen-containing gas; and a fuel cell 6 that generates the power by using the hydrogen-containing gas supplied from the reformer. The reformer and a flow channel of a fuel cell are formed of a ferritic stainless steel containing aluminum, and a flow channel of the hydrodesulfurization unit is formed of a ferritic stainless steel.

Description

  The present invention relates to a solid oxide fuel cell hot module and a solid oxide fuel cell system including the hot module.

The fuel cell system supplies chemical energy generated by supplying a hydrogen-containing gas and an oxygen-containing gas to the fuel cell stack, which is the main body of the power generation unit, to advance an electrochemical reaction between hydrogen and oxygen. This system generates electricity as electrical energy and generates electricity. The fuel cell stack is composed of cells including a fuel electrode, an electrolyte, and an air electrode. Methane, which is fuel, hydrogen and CO reformed by a reformer, and water vapor are supplied to the fuel electrode. Air is supplied to the air electrode, dissociates at the interface with the electrolyte, diffuses and moves through the electrolyte, and reacts with hydrogen and CO on the fuel electrode side at the interface between the electrolyte and the fuel electrode to produce water and CO ₂ . . Electricity is generated by electrons released during this reaction.

  In addition, high-efficiency power generation is possible, and heat energy generated during power generation operation can be easily used, so development is being promoted as a distributed power generation system that can achieve high energy use efficiency. ing.

  As the raw material for the hydrogen-containing gas, a city gas mainly composed of natural gas or a fossil raw material such as LPG is used. The hydrogen generator is a reformer that generates hydrogen-containing gas (reformed gas) by reacting the raw material with water vapor using a Ru catalyst or Ni catalyst at a temperature of, for example, 600 to 700 ° C. (reforming reaction). Equipped with a bowl.

  An odorant containing a sulfur component is added to a raw material such as city gas or LPG in order to detect leakage of the raw material. Moreover, the sulfur compound derived from a raw material may be contained. These sulfur-based odorants and naturally-occurring sulfur compounds (collectively referred to as “sulfur compounds”) poison the catalysts such as Ru catalysts and Ni catalysts used in the reformer and inhibit the reforming reaction. Or poison the anode of the fuel cell stack, which may impair the performance of the fuel cell. For this reason, the hydrogen generator is generally provided with a desulfurizer for removing sulfur compounds from the raw material before being introduced into the reformer.

  Patent Document 1 discloses a compressor that boosts the raw fuel, a desulfurizer that removes sulfur in the raw fuel, a reformer that generates hydrogen-rich gas from the raw fuel by steam reforming, and the hydrogen-rich gas Disclosed is a fuel cell power plant characterized by comprising means for returning a part of the hydrogen to the suction side of the raw fuel compressor as desulfurization hydrogen (Claim 1).

  Patent Document 2 discloses a fuel cell power generation system having at least a desulfurization apparatus that desulfurizes raw fuel and a steam reformer that reforms the desulfurized raw fuel into a fuel gas containing hydrogen as a main component. A fuel cell power generation system comprising a desulfurizer filled with a desulfurizing agent is disclosed (claim 1).

  Patent Document 3 receives a first desulfurizer 2 that removes a sulfur component of a raw material gas containing hydrogen by hydrodesulfurization, and a desulfurized raw material gas from which the sulfur component has been removed by the first desulfurizer 2. The first reformer 3 for generating fuel gas by reforming the fuel and the fuel gas generated by the first reformer 3 are received, and the fuel gas and the air supplied from the outside are caused to generate and react to generate power. A fuel cell 4 that performs partial reforming of the raw material gas by a partial oxidation reaction to generate a partially reformed raw material gas containing hydrogen, and the generated partial reformed raw material gas as a raw material gas containing hydrogen A fuel cell system including a second reformer 1 that supplies the fuel to the fuel cell 2 is disclosed (summary).

  Patent Document 4 states that the shape of the desulfurizing agent to be put into the desulfurizer may be a spherical shape or a pellet shape used in a normal catalyst, and this material can also be used after being molded into a honeycomb shape, a cylindrical shape, or a hollow cylindrical shape. There is disclosure (paragraph 0012).

  Patent Document 5 discloses a fuel processing apparatus in which an outer cylinder has an outer cylinder upper part, an outer cylinder middle part, and an outer cylinder lower part, which are integrally manufactured by press-drawing a single metal plate. Item 2). Here, the material of the metal plate is preferably austenitic stainless steel. As described above, since the fuel processing device becomes high temperature during operation, the high temperature durability of the fuel processing device is increased by using austenitic stainless steel having high temperature durability as the material of the metal plate constituting the outer cylinder. . In addition, austenitic stainless steel is easier to extend than other types of stainless steel (for example, ferritic). For this reason, it is preferable from the viewpoint of forming processability that the material of the metal plate is austenitic stainless steel (paragraph 0037).

JP 7-320761 A JP-A-11-139803 JP 2013-101822 A Japanese Patent No. 3455991 Japanese Patent No. 4918629

  An object of the present invention is to improve the durability of a solid oxide fuel cell hot module and a solid oxide fuel cell system including the hot module.

  An aspect of a hot module for a solid oxide fuel cell according to the present invention includes a hydrodesulfurizer that removes sulfur compounds in a raw material, and a hydrogen that is produced by reforming a raw material supplied from the hydrodesulfurizer. A reformer that generates a contained gas; and a solid oxide fuel cell that generates power using a hydrogen-containing gas supplied from the reformer, the reformer and the solid oxide fuel cell. The flow path is made of ferritic stainless steel containing aluminum, and the flow path of the hydrodesulfurizer is made of ferritic stainless steel.

  An aspect of the solid oxide fuel cell system according to the present invention includes the above-described hot module for a solid oxide fuel cell.

  According to one aspect of the present invention, it is possible to improve the durability of a solid oxide fuel cell hot module and a solid oxide fuel cell system including the same.

FIG. 1 is a block diagram showing an example of a schematic configuration of a solid oxide fuel cell hot module according to the first embodiment. FIG. 2 is a block diagram showing an example of a schematic configuration of a solid oxide fuel cell hot module according to the second embodiment. FIG. 3 is a block diagram showing an example of a schematic configuration of the solid oxide fuel cell hot module according to the first embodiment. FIG. 4 is a block diagram showing an example of a schematic configuration of the solid oxide fuel cell hot module according to the second embodiment.

  In the hydrodesulfurization method, a hydrogenation reaction is performed by hydrogenating (hydrogenating) a sulfur compound at a high temperature using a hydrogenation catalyst to form hydrogen sulfide, and a desulfurization reaction in which the hydrogen sulfide is removed by a chemical reaction. These reactions are collectively called hydrodesulfurization reaction. Since the hydrodesulfurization method uses a chemical reaction, for example, the desulfurization capacity can be increased and the size of the desulfurizer can be reduced compared to the adsorption desulfurization method using an adsorbent.

  The solid oxide fuel cell generally has a high operating temperature of 700 ° C. to 1000 ° C., and stainless steel is used to maintain the strength of the structure in the high temperature part. Stainless steel usually contains Cr, but if stainless steel containing Cr is used in the high temperature part, Cr oxide formed on the stainless steel surface evaporates and reacts with the cell air electrode surface, which is called Cr poisoning. Deterioration may occur.

  In order to reduce the possibility of Cr poisoning, it is conceivable to employ stainless steel containing Al in an interconnector and a current collector that use a metal material in a cell of a solid oxide fuel cell. Stainless steel containing Al is formed with an Al oxide coating on the outermost surface of the material and a Cr oxide coating on the lower layer at a high temperature, thereby strongly protecting the progress of oxidation of the base material. For this reason, the effect which prevents Cr poisoning concerned with a solid oxide fuel cell beforehand is anticipated.

  In addition, the reformer, stack peripheral structure, and pipes that make up the solid oxide fuel cell also use Al-containing stainless steel to prevent Cr oxide from evaporating and scattering. It is possible to do.

  Therefore, an experiment was conducted by producing a hot module for a solid oxide fuel cell in which the flow path of the reformer and the solid oxide fuel cell is made of ferritic stainless steel containing aluminum. At this time, the hydrodesulfurizer was considered not to generate Cr poisoning due to evaporation of Cr oxide because the temperature during operation was not so high. In addition, the production cost of austenitic stainless steel can be lower than that of ferritic stainless steel. Therefore, the flow path of the hydrodesulfurizer is made of austenitic stainless steel as usual.

  In such a configuration, although the Cr poisoning of the catalyst is reduced, it has been found that there is room for improvement in the durability of the hot module for a solid oxide fuel cell. As a result of detailed examination, it has been found that deterioration is particularly concentrated at the connecting portion between the reformer and the hydrodesulfurizer by repeated start-stop. As a result of further investigation of the cause, it was noted that there is a difference in the coefficient of linear expansion because the composition of the stainless steel constituting the flow path is different between the hydrodesulfurizer and the reformer. This is because if the composition is different between the two members connected to each other, the stress at the time of expansion and contraction is concentrated on the connection portion, which may cause deterioration.

  In order to reduce such a problem, it is conceivable that the flow path of the hydrodesulfurizer is made of ferritic stainless steel. With such a configuration, the strength of the connection portion between the hydrodesulfurizer and the reformer can be increased while reducing Cr poisoning, and thus the problem that the durability of the hot module for a solid oxide fuel cell can be improved. It can be solved at the same time.

  Further, even if the same ferritic stainless steel is used, one having a low Al content (including one not containing Al) is less expensive than one having a high Al content. It has also been found that the coefficient of linear expansion of the material does not change significantly. Therefore, the flow path of the hydrodesulfurizer is made of ferritic stainless steel with a relatively low Al content to reduce Cr poisoning and improve the durability and manufacture of hot modules for solid oxide fuel cells. The problem of cost reduction can be solved all at once.

  Further investigation revealed that the desulfurization agent with a honeycomb structure is constructed by adhering a catalyst to the surface of a support made of metal or ceramics formed in a honeycomb shape, so it has an excellent structure because of its high durability in terms of strength. It is. However, due to the complexity of the manufacturing process, there is a problem that the manufacturing cost is high, and there is a big problem in order to stably realize a large amount of manufacturing.

  On the other hand, a granular desulfurizing agent is manufactured by attaching a catalyst to the surface of a support manufactured by a wet or dry molding method, and the manufacturing process is simplified compared to a desulfurizing agent having a honeycomb structure, and the desulfurizing agent is inexpensive. Can be mass-produced.

  Since the fuel cell system is periodically stopped or stopped in error, the components including the hydrodesulfurizer repeat a low temperature state in the stopped state and a high temperature state in the operating state. In the hydrodesulfurizer, the above-described temperature cycle causes the stainless steel constituting the desulfurizer to thermally expand in a high temperature state, and contracts in a low temperature state as compared to a high temperature state. Due to expansion and contraction of the desulfurizer, the granular desulfurization agent used in the desulfurizer may be cracked due to repeated stress. If the granular desulfurization agent breaks, the desulfurization performance may be reduced, or the powdered desulfurization agent may block the gas flow path, causing a pressure increase.

  Generally, ferritic stainless steel has a smaller coefficient of linear expansion than austenitic stainless steel. Constructing the flow path of the hydrodesulfurizer with ferritic stainless steel leads to a reduction in expansion and contraction associated with a temperature change of the flow path. Therefore, it was also found that in the configuration in which the granular hydrodesulfurization catalyst is filled in the flow path of the hydrodesulfurizer, the collapse of the granules due to the expansion and contraction of the flow path can be reduced.

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

  Each of the embodiments described below shows a specific example of the present invention. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and do not limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are described as optional constituent elements. In the drawings, the same reference numerals are sometimes omitted. In addition, the drawings schematically show the respective components for easy understanding, and there are cases where the shape, dimensional ratio, and the like are not accurately displayed. Moreover, in a manufacturing method, the order of each process etc. can be changed as needed, and another well-known process can be added.

(First embodiment)
The hot module for a solid oxide fuel cell according to the first embodiment generates a hydrogen-containing gas by reforming a hydrodesulfurizer that removes sulfur compounds in the raw material and a raw material supplied from the hydrodesulfurizer. A reformer and a solid oxide fuel cell that generates electricity using a hydrogen-containing gas supplied from the reformer, and the flow path of the reformer and the solid oxide fuel cell contains aluminum It is made of ferritic stainless steel, and the flow path of the hydrodesulfurizer is made of ferritic stainless steel.

  With such a configuration, the strength of the connecting portion between the hydrodesulfurizer and the reformer can be increased while reducing Cr poisoning, and therefore the durability of the hot module for a solid oxide fuel cell can be improved.

  In the above hot module for a solid oxide fuel cell, the ferritic stainless steel in which the aluminum content of the ferritic stainless steel constituting the flow path of the hydrodesulfurizer constitutes the reformer and the flow path of the solid oxide fuel cell The aluminum content may be lower.

  With such a configuration, it is possible not only to improve the durability of the hot module for a solid oxide fuel cell while reducing Cr poisoning, but also to reduce the manufacturing cost.

  In the solid oxide fuel cell hot module, the hydrodesulfurizer may be detachably connected to the reformer.

  Further, in this configuration, the capacity of the hydrodesulfurizer (including the case where no hydrodesulfurizer is provided) can be selected according to the concentration of the sulfur compound in the raw material, so that various raw material compositions can be handled.

  The solid oxide fuel cell system according to the first embodiment includes the hot module for a solid oxide fuel cell.

  FIG. 1 is a block diagram showing an example of a schematic configuration of a solid oxide fuel cell hot module according to the first embodiment. Hereinafter, the hot module 100 for a solid oxide fuel cell according to the first embodiment will be described with reference to FIG.

  In the example shown in FIG. 1, a solid oxide fuel cell hot module 100 includes a hydrodesulfurizer 2, a reformer 4, and a solid oxide fuel cell 6.

  The hydrodesulfurizer 2 removes sulfur compounds in the raw material. The flow path of the hydrodesulfurizer 2 is made of ferritic stainless steel. The aluminum content of the ferritic stainless steel constituting the flow path of the hydrodesulfurizer 2 may be lower than the aluminum content of the ferritic stainless steel constituting the flow path of the reformer 4 and the solid oxide fuel cell 6. Good. Here, “lower than the aluminum content of the ferritic stainless steel constituting the flow path of the reformer 4 and the solid oxide fuel cell 6” means the ferritic stainless steel constituting the flow path of the hydrodesulfurizer 2. This includes cases where the aluminum content of the steel is zero.

  In this specification, the phrase “the flow path is made of a predetermined material” more specifically means that “at least a portion of the flow path that contacts the fluid flowing through the flow path is in contact with the flow path. It may mean “consisting of a predetermined material” (the same applies hereinafter).

  Specifically, for example, the aluminum content of the ferritic stainless steel constituting the flow path of the hydrodesulfurizer 2 can be 0 wt% or more and less than 2.0 wt%. The aluminum content of the ferritic stainless steel constituting the flow path of the hydrodesulfurizer 2 may be 0% by weight or more and less than 1.0% by weight. The content of aluminum in the ferritic stainless steel constituting the flow path of the hydrodesulfurizer 2 may be inevitable impurity concentration or less.

The linear expansion coefficient in the range of 0 ° C. to 400 ° C. of the ferritic stainless steel constituting the hydrodesulfurizer 2 and the flow path of the hydrodesulfurizer 2 may be smaller than 12 × 10 ⁻⁶ / ° C. In such a configuration, powdering of the hydrodesulfurization agent due to expansion and contraction accompanying the temperature cycle due to the start and stop of the hot module can be suppressed.

  The hydrodesulfurizer 2 removes the sulfur compound in the raw material by adding hydrogen. As the hydrogen, for example, hydrogen contained in a gas discharged from the reformer 4 and the solid oxide fuel cell 6 can be used. Specifically, for example, a recycle gas flow path in which a hydrogen-containing gas discharged from the reformer 4 branches from an anode gas supply flow path that connects the reformer 4 and the anode of the solid oxide fuel cell 6; The material may be supplied to the raw material supply flow path via a recycle gas supply unit that is provided in the recycle gas flow path and adjusts the supply amount of the recycle gas. The raw material supply channel is a channel for supplying the raw material to the hydrodesulfurizer 2.

  The raw material can be, for example, city gas containing methane as a main component, natural gas, gas containing an organic compound containing carbon and hydrogen as constituent elements, such as LPG, kerosene, and alcohol such as methanol and ethanol. City gas refers to gas supplied from gas companies to households through piping.

  The sulfur compound may be artificially added to the raw material as an odorant component, or may be a natural sulfur compound derived from the raw material itself. Specifically, tertiary butylmercaptan (TBM), dimethyl sulfide (DMS), tetrahydrothiophene (THT), carbonyl sulfide (COS), hydrogen sulfide, etc. Is exemplified.

  The flow path of the hydrodesulfurizer 2 may be filled with a granular hydrodesulfurization agent. Examples of the hydrodesulfurization agent include a CuZn-based catalyst (for example, a Cu-Zn-Ni-based catalyst and a Cu--) having both a function of converting a sulfur compound into hydrogen sulfide by a hydrogenation reaction and a function of adsorbing hydrogen sulfide. Zn-Fe catalyst etc. can be used. The hydrodesulfurization agent is not limited to this example, and is a CoMo-based catalyst that converts a sulfur compound in the raw material gas into hydrogen sulfide, and a sulfur adsorbent that is provided downstream thereof to adsorb and remove hydrogen sulfide. You may comprise with a ZnO type catalyst or a CuZn type catalyst. The hydrodesulfurizing agent is used after being heated to a predetermined temperature. The temperature of the hydrodesulfurizer 2 (the temperature of the hydrodesulfurization agent) during the operation of the solid oxide fuel cell hot module is, for example, 150 to 320 degrees Celsius, or 180 to 320 degrees Celsius, or 250 to 300 degrees Celsius. It can be.

  The granular hydrodesulfurization agent is filled in a desulfurization vessel. The desulfurization vessel is maintained at 200 ° C. to 300 ° C., which is a temperature at which the hydrodesulfurization reaction proceeds sufficiently, and a sulfur gas contained in the raw material gas is desulfurized by flowing a raw material gas and a hydrogen-containing gas therein. I do. In order to exhibit the desired desulfurization performance and to have high durability performance, it is desirable that the temperature distribution of the desulfurizer is small and kept constant. Ferritic stainless steel is characterized by high thermal conductivity compared to austenitic stainless steel. Ferritic stainless steel is expected to have a uniform temperature distribution because of its high thermal conductivity.

  The hydrodesulfurizer 2 may be detachably connected to the reformer 4. As a specific configuration for detachably connecting the hydrodesulfurizer 2 and the reformer 4, for example, a commercially available pipe joint or the like (for example, a joint that is tightened with a nut) can be employed. Since the capacity of the hydrodesulfurizer 2 can be selected according to the concentration of the sulfur compound in the raw material (including the case where the hydrodesulfurizer 2 is not provided at all), various raw material compositions can be handled. Moreover, when the desulfurization performance of the hydrodesulfurizer 2 is lowered, the hydrodesulfurizer 2 can be easily replaced.

  In this case, the hydrodesulfurizer 2 can include a pipe that leads to a connection portion between the hydrodesulfurizer 2 and the reformer 4. Further, the reformer 4 can include a pipe that leads to a connecting portion between the hydrodesulfurizer 2 and the reformer 4.

  The reformer 4 reforms the raw material supplied from the hydrodesulfurizer 2 to generate a hydrogen-containing gas. The flow path of the reformer 4 is made of ferritic stainless steel containing aluminum. Specifically, for example, the content of aluminum of ferritic stainless steel constituting the flow path of the reformer 4 can be 2.0 wt% or more and 3.0 wt% or less.

  The reforming reaction that proceeds in the reformer 4 may take any form, and examples thereof include a steam reforming reaction, an autothermal reaction, and a partial oxidation reaction. The temperature of the reformer 4 (the temperature of the reforming catalyst) during operation of the solid oxide fuel cell hot module may be, for example, 500 to 700 degrees Celsius, or 550 to 650 degrees Celsius.

  A reforming catalyst is disposed inside the reformer 4. By this reforming catalyst, the reforming reaction proceeds, and for example, a hydrogen-containing gas can be generated from the raw material and water. The heat required for the reforming reaction may be supplied from, for example, a combustor (not shown). In general, as the reforming catalyst, at least one selected from the group consisting of noble metal catalysts such as Pt, Ru and Rh and Ni is preferably used. In the hydrogen generator of the present embodiment, a reforming catalyst containing Ru is used.

  The solid oxide fuel cell 6 generates power using the hydrogen-containing gas supplied from the reformer. The flow path of the solid oxide fuel cell 6 is made of ferritic stainless steel containing aluminum. Specifically, for example, the content of aluminum in ferritic stainless steel constituting the flow path of the solid oxide fuel cell 6 can be 2.0 wt% or more and 3.0 wt% or less.

  The solid oxide fuel cell 6 includes an anode and a cathode. The solid oxide fuel cell 6 performs a power generation reaction between a hydrogen-containing gas supplied to the anode and an oxygen-containing gas supplied to the cathode. The hydrogen-containing gas is supplied from the reformer 8. The oxygen-containing gas can be air, for example. The oxygen-containing gas may be supplied from the outside of the solid oxide fuel cell system, or may be supplied from an oxygen-containing gas supply device (not shown) including a blower and a pump.

  The solid oxide fuel cell 6 is configured to include, for example, a stack in which a plurality of fuel cell single cells that generate power by performing a power generation reaction between an anode and a cathode are connected in series. The stack may be a closed type in which the anode off gas and the cathode off gas are discharged without being mixed, or may be an open type in which the anode off gas and the cathode off gas are discharged after being mixed. In the case of an open stack, the anode off-gas and the cathode off-gas may be mixed and then burned in a combustor immediately after the stack.

  The temperature (cell temperature) of the solid oxide fuel cell 6 during the operation of the solid oxide fuel cell hot module can be set to, for example, 500 to 700 degrees Celsius.

  For example, a known configuration in which yttria-stabilized zirconia (YSZ) is used as an electrolyte may be employed for the single fuel cell. As a material for the fuel cell unit cell, it is also possible to use zirconia doped with yttrium or scandium, or a lanthanum gallate solid electrolyte. In a fuel cell unit cell using yttria-stabilized zirconia, for example, a power generation reaction is performed in a temperature range of about 600 degrees Celsius to 1000 degrees Celsius, depending on the thickness of the electrolyte.

  The electric power obtained by the power generation of the solid oxide fuel cell 6 is supplied to an external load via a terminal (not shown).

  Table 1 gives examples of thermal expansion coefficients of various stainless steels. The sources are as follows.

Stainless Steel Association http://www.jssa.gr.jp/contents/faq-article/q6/
NCA-1 http://products.nisshin-steel.co.jp/pdfs/stainless_fe_nca_1.pdf
NSSC http://ns-sc.co.jp/pdf/product/stainless_sheet_j_12-03.pdf
SUS405 http://nsfellowslibrary.web.fc2.com/catalog-nissin-Sus.pdf

As shown in Table 1, generally, ferritic stainless steel (thermal expansion coefficient: 10.0-) is higher than austenitic stainless steel (thermal expansion coefficient: 14.4 to 18.7 × 10 ⁻⁶ [/ ° C.]). 14.2 × 10 ⁻⁶ [/ ° C.]) has a smaller coefficient of thermal expansion. As shown in Table 1, this tendency does not change even if the ferritic stainless steel contains aluminum. Therefore, the flow path of the hydrodesulfurizer 2, the reformer 4, and the solid oxide fuel cell 6 are all made of ferritic stainless steel, so that the connecting portion between the hydrodesulfurizer 2 and the reformer 4 The durability of the hot module 100 for a solid oxide fuel cell is improved.

  Further, when the flow path of the reformer 4 and the solid oxide fuel cell 6 is made of ferritic stainless steel containing aluminum, the flow path of the hydrodesulfurizer 2 is made of ferritic stainless steel. Compared with the case where the flow path of the hydrodesulfurizer 2 is made of austenitic stainless steel, it is expected that the difference in thermal expansion coefficient between the flow paths will be small. Accordingly, the strength of the connecting portion between the hydrodesulfurizer and the reformer can be increased while reducing Cr poisoning, so that the durability of the hot module for a solid oxide fuel cell can be improved.

  Ferritic stainless steel is cheaper when the aluminum content is lower. Therefore, the aluminum content of the ferritic stainless steel constituting the flow path of the hydrodesulfurizer 2 is lower than the aluminum content of the ferritic stainless steel constituting the flow path of the reformer 4 and the solid oxide fuel cell 6. In some cases, the manufacturing cost of the solid oxide fuel cell hot module can be reduced as compared to the case where it is not.

(Second Embodiment)
The hot module for a solid oxide fuel cell according to the second embodiment is the hot module for a solid oxide fuel cell according to the first embodiment, and further, water is generated by exhaust gas discharged from the solid oxide fuel cell. A heater for heating the desulfurizer is provided, and the flow path of the heater is made of ferritic stainless steel.

  In such a configuration, the strength of not only the connecting portion between the hydrodesulfurizer and the reformer but also the connecting portion between the solid oxide fuel cell and the heater can be increased while reducing Cr poisoning. The durability of the oxide fuel cell hot module can be improved.

  In the above-mentioned hot module for a solid oxide fuel cell, the aluminum content of the ferritic stainless steel constituting the flow path of the heater is the aluminum of the ferritic stainless steel constituting the flow path of the reformer and the solid oxide fuel cell. It may be lower than the content.

  With such a configuration, it is possible not only to improve the durability of the hot module for a solid oxide fuel cell while reducing Cr poisoning, but also to reduce the manufacturing cost.

  In the hot module for a solid oxide fuel cell, the hydrodesulfurizer may be detachably attached to the reformer, and the heater may be detachably attached to the solid oxide fuel cell.

  In this configuration, the hydrodesulfurizer is heated by the heater, and the hydrodesulfurizer capacity (including the case where no hydrodesulfurizer is provided) according to the concentration of the sulfur compound in the raw material and this Since the heater corresponding to can be selected, it can respond to various raw material compositions.

  A solid oxide fuel cell system according to a second embodiment includes the hot module for a solid oxide fuel cell.

  FIG. 2 is a block diagram showing an example of a schematic configuration of a solid oxide fuel cell hot module according to the second embodiment. Hereinafter, the solid oxide fuel cell hot module 200 according to the first embodiment will be described with reference to FIG.

  In the example shown in FIG. 2, the solid oxide fuel cell hot module 200 includes a heater 8. The heater 8 can maintain the temperature of the hydrodesulfurizer 2 in a suitable range.

  The heater 8 heats the hydrodesulfurizer 2 with the exhaust gas discharged from the solid oxide fuel cell 6. The flow path of the heater 8 is made of ferritic stainless steel. The aluminum content of the ferritic stainless steel constituting the flow path of the heater 8 may be lower than the aluminum content of the ferritic stainless steel constituting the flow path of the reformer 4 and the solid oxide fuel cell 6. Here, “lower than the aluminum content of the ferritic stainless steel constituting the flow path of the reformer 4 and the solid oxide fuel cell 6” means that the ferritic stainless steel constituting the flow path of the heater 8 is used. Including the case where the aluminum content is zero.

  Specifically, for example, the content of aluminum of ferritic stainless steel constituting the flow path of the heater 8 can be 0 wt% or more and less than 2.0 wt%. The aluminum content of the ferritic stainless steel constituting the flow path of the heater 8 may be not less than 0% by weight and less than 1.0% by weight. The content of aluminum in the ferritic stainless steel constituting the flow path of the heater 8 may be inevitable impurity concentration or less.

  Since the other components can be the same as those of the solid oxide fuel cell hot module 100 shown in FIG. 1, the same reference numerals and names are used for the same components in FIG. 1 and FIG. Therefore, the description is omitted.

  In the configuration of this embodiment, the strength of not only the connecting portion between the hydrodesulfurizer and the reformer but also the connecting portion between the solid oxide fuel cell and the heater can be increased while reducing Cr poisoning. Therefore, the durability of the hot module for a solid oxide fuel cell can be improved.

  The aluminum content of the ferritic stainless steel constituting the flow path of the heater 8 may be lower than the aluminum content of the ferritic stainless steel constituting the flow path of the reformer 4 and the solid oxide fuel cell 6. In this case, not only the durability of the hot module for a solid oxide fuel cell can be improved while reducing Cr poisoning, but also the manufacturing cost can be reduced.

  The hydrodesulfurizer 2 may be detachably attached to the reformer 4, and the heater 8 may be detachably attached to the solid oxide fuel cell 6. In this case, furthermore, in the configuration in which the hydrodesulfurizer 2 is heated by the heater 8, the capacity of the hydrodesulfurizer 2 (the hydrodesulfurizer 2 is not provided at all according to the concentration of the sulfur compound in the raw material). And the heater 8 corresponding to this can be selected, so that various raw material compositions can be handled.

  Also in the second embodiment, the same modifications as in the first embodiment are possible.

(First embodiment)
FIG. 3 is a block diagram showing an example of a schematic configuration of the solid oxide fuel cell hot module according to the first embodiment.

  As shown in FIG. 3, the solid oxide fuel cell hot module 300 according to the first embodiment includes a hydrodesulfurizer 1, a heater 7 provided for heating the hydrodesulfurizer 1, and a raw material A reformer 3 for reforming the gas, a fuel cell stack 5 for generating electricity, a first pipe 11 for sending the raw material gas from which the sulfur compound has been removed by the hydrodesulfurizer 1 to the reformer, and reforming A third pipe 13 for sending gas to the fuel cell stack 5, a fourth pipe 14 for sending a part of the reformed gas to the hydrodesulfurizer, and a heater for exhaust gas discharged from the fuel cell stack 5 And a second pipe 12 for sending to the second pipe 12.

  The first pipe 11 and the fourth pipe 14 may be a part of the hydrodesulfurizer 1 or a part of the reformer 3. Part of the first pipe 11 and the fourth pipe 14 may be part of the hydrodesulfurizer 1, and the other part may be part of the reformer 3. Of the first pipe 11 and the fourth pipe 14, a part that is a part of the hydrodesulfurizer 1 becomes a part of the flow path of the hydrodesulfurizer 1. Of the first pipe 11 and the fourth pipe 14, a part that is a part of the reformer 3 becomes a part of the flow path of the reformer 3.

  The second pipe 12 may be a part of the heater 7 or a part of the fuel cell stack 5. A part of the second pipe 12 may be a part of the heater 7, and the other part may be a part of the fuel cell stack 5. A part of the second pipe 12 that is a part of the heater 7 is a part of a flow path of the heater 7. A portion of the second pipe 12 that is a part of the fuel cell stack 5 becomes a part of the flow path of the fuel cell stack 5.

  The third pipe 13 may be a part of the reformer 3 or a part of the fuel cell stack 5. Part of the third pipe 13 may be part of the reformer 3, and the other part may be part of the fuel cell stack 5. A portion of the third pipe 13 that is a part of the reformer 3 becomes a part of the flow path of the reformer 3. A portion of the third pipe 13 that is a part of the fuel cell stack 5 becomes a part of the flow path of the fuel cell stack 5.

  Except for the above points, the hydrodesulfurizer 1 can be configured similarly to the hydrodesulfurizer 2 of the first embodiment, and the reformer 3 is similar to the reformer 4 of the first embodiment. The fuel cell stack 5 can be configured similarly to the solid oxide fuel cell 6, and the heater 7 can be configured similar to the heater 8 of the second embodiment. . Therefore, detailed description is omitted.

  Also in the first example, the same modifications as those of the first and second embodiments are possible.

(Second embodiment)
FIG. 4 is a block diagram showing an example of a schematic configuration of the solid oxide fuel cell hot module according to the second embodiment.

  As shown in FIG. 4, the hot module 400 for a solid oxide fuel cell according to the second embodiment is a first pipe for sending the raw material gas from which the sulfur compound has been removed by the hydrodesulfurizer 1 to the reformer 3. 11, a fourth pipe 14 for sending a part of the reformed gas to the hydrodesulfurizer 1, and a second pipe 12 for sending the exhaust gas generated in the fuel cell stack 5 to the heater 7. As possible mechanisms (mechanisms for separating the upstream side and the downstream side by separating the pipes halfway), a first connection part 21, a second connection part 22, and a third connection part 23 are provided. As such a mechanism, for example, a commercially available pipe joint or the like (for example, a joint that is tightened with a nut) can be used.

  In the first pipe 11, a portion on the upstream side (hydrogenation desulfurizer side) of the first connection portion 21 may be made of ferritic stainless steel. Of the first pipe 11, the aluminum content of the ferritic stainless steel constituting the upstream portion of the first connection portion 21 is the ferritic stainless steel aluminum constituting the flow path of the reformer 3 and the fuel cell stack 5. It may be lower than the content.

  Specifically, for example, the content of aluminum in the ferritic stainless steel constituting the upstream portion of the first connecting portion 21 in the first pipe 11 is 0 wt% or more and less than 2.0 wt%. be able to. The content of aluminum in the ferritic stainless steel constituting the upstream portion of the first connection portion 21 in the first pipe 11 may be 0 wt% or more and less than 1.0 wt%. In the first pipe 11, the content of aluminum in the ferritic stainless steel constituting the flow path in the upstream portion of the first connection portion 21 may be inevitable impurity concentration or less.

  In the first pipe 11, a portion on the downstream side (reformer side) of the first connection portion 21 may be made of ferritic stainless steel containing aluminum. Specifically, for example, the content of aluminum of ferritic stainless steel constituting the downstream portion of the first connection portion 21 in the first pipe 11 is 2.0 wt% or more and 3.0 wt% or less. It can be.

  In the second pipe 12, the portion on the downstream side (heater side) of the third connection portion 23 may be made of ferritic stainless steel. Of the second pipe 12, the aluminum content of the ferritic stainless steel constituting the downstream portion of the third connecting portion 23 is the ferritic stainless steel constituting the flow path of the reformer 4 and the solid oxide fuel cell 6. It may be lower than the aluminum content of the steel.

  Specifically, for example, the content of aluminum in the ferritic stainless steel constituting the downstream portion of the third connection portion 23 in the second pipe 12 is 0 wt% or more and less than 2.0 wt%. be able to. In the second pipe 12, the content of aluminum in the ferritic stainless steel constituting the downstream portion of the third connection portion 23 may be 0 wt% or more and less than 1.0 wt%. In the second pipe 12, the content of aluminum in the ferritic stainless steel constituting the flow path in the downstream portion of the third connection portion 23 may be inevitable impurity concentration or less.

  In the second pipe 12, a portion on the upstream side (fuel cell stack side) of the third connection portion 23 may be made of ferritic stainless steel containing aluminum. Specifically, for example, the content of aluminum of ferritic stainless steel constituting the downstream portion of the first connection portion 21 in the first pipe 11 is 2.0 wt% or more and 3.0 wt% or less. It can be.

  The third pipe 13 is made of ferritic stainless steel containing aluminum. Specifically, for example, the content of aluminum in the ferritic stainless steel constituting the third pipe 13 can be 2.0 wt% or more and 3.0 wt% or less.

  In the fourth pipe 14, the portion on the downstream side (hydrogenation desulfurizer side) of the second connection portion 22 may be made of ferritic stainless steel. Of the fourth pipe 14, the aluminum content of the ferritic stainless steel constituting the downstream portion of the second connecting portion 22 is the aluminum content of the ferritic stainless steel constituting the flow path of the reformer 3 and the fuel cell stack 5. It may be lower than the content.

  Specifically, for example, the aluminum content of the ferritic stainless steel constituting the downstream portion of the second connection portion 22 in the fourth pipe 14 is 0 wt% or more and less than 2.0 wt%. be able to. In the fourth pipe 14, the aluminum content of the ferritic stainless steel constituting the downstream portion of the second connection portion 22 may be 0 wt% or more and less than 1.0 wt%. In the fourth pipe 14, the content of aluminum in the ferritic stainless steel constituting the flow path in the downstream portion of the second connection portion 22 may be inevitable impurity concentration or less.

  In the fourth pipe 14, the upstream (reformer side) portion of the second connection portion 22 may be made of ferritic stainless steel containing aluminum. Specifically, for example, the content of aluminum of ferritic stainless steel constituting the upstream portion of the second connection portion 22 in the fourth pipe 14 is 2.0 wt% or more and 3.0 wt% or less. It can be.

  Except for the above points, the solid oxide fuel cell hot module 400 can have the same configuration as the solid oxide fuel cell hot module 300 according to the first embodiment. Therefore, the same reference numerals and names are given to the same components in FIG. 4 and FIG.

  In the configuration of the second embodiment, when the desulfurization performance of the hydrodesulfurizer 1 is deteriorated, the hydrodesulfurizer 1 can be easily replaced with a new one, and further, the hydrodesulfurizer having the above configuration is used. In the case of a hydrogen generator that does not require 1, a hydrogen generator excluding the hydrodesulfurizer 1 and the heater 7 and a hot module for a solid oxide fuel cell can be provided.

  Also in the second example, the same modifications as those of the first embodiment, the second embodiment, and the first example are possible.

  From the foregoing description, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and / or function may be substantially changed without departing from the spirit of the invention.

  One embodiment of the present invention is useful as a solid oxide fuel cell hot module that can improve the durability of the solid oxide fuel cell hot module.

DESCRIPTION OF SYMBOLS 1 Hydrodesulfurizer 2 Hydrodesulfurizer 3 Reformer 4 Reformer 5 Fuel cell stack 6 Solid oxide fuel cell 7 Heater 8 Heater 11 1st piping 12 2nd piping 13 3rd piping 14 4th Piping 21 First connection portion 22 Second connection portion 23 Third connection portion 100 Hot module for a solid oxide fuel cell 200 Hot module for a solid oxide fuel cell 300 Hot module for a solid oxide fuel cell 400 Solid oxide Fuel cell hot module

Claims (7)

A hydrodesulfurizer that removes sulfur compounds in the raw material;
A reformer for reforming the raw material supplied from the hydrodesulfurizer to generate a hydrogen-containing gas;
A solid oxide fuel cell that generates electricity using the hydrogen-containing gas supplied from the reformer,
The flow path of the reformer and the solid oxide fuel cell is composed of ferritic stainless steel containing aluminum,
The flow path of the hydrodesulfurizer is made of ferritic stainless steel,
Hot module for solid oxide fuel cells. The aluminum content of the ferritic stainless steel constituting the flow path of the hydrodesulfurizer is lower than the aluminum content of the ferritic stainless steel constituting the flow path of the reformer and the solid oxide fuel cell,
The hot module for a solid oxide fuel cell according to claim 1. The hydrodesulfurizer is detachably connected to the reformer,
The hot module for a solid oxide fuel cell according to claim 1 or 2. And a heater for heating the hydrodesulfurizer with exhaust gas discharged from the solid oxide fuel cell,
The flow path of the heater is made of ferritic stainless steel,
The hot module for a solid oxide fuel cell according to any one of claims 1 to 3. The aluminum content of the ferritic stainless steel constituting the flow path of the heater is lower than the aluminum content of the ferritic stainless steel constituting the flow path of the reformer and the solid oxide fuel cell,
The hot module for solid oxide fuel cells according to claim 4. The hydrodesulfurizer is detachably attached to the reformer,
The heater is detachably attached to the solid oxide fuel cell.
The hot module for a solid oxide fuel cell according to claim 4 or 5.   A fuel cell system comprising the solid oxide fuel cell hot module according to claim 1.

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