desulfurizer

Abstract

To provide a desulfurizer capable of improving desulfurization ability.SOLUTION: A desulfurizer that desulfurizes a sulfur component contained in a raw material for reforming includes a housing 60 that includes desulfurizing agent filling portions 613 and 615 filled with a desulfurizing agent that removes the sulfur component from the reforming raw material as the reforming raw material flows, and a heating flow path portion 83 that guides a heating fluid that heats the desulfurizing agent by exchanging heat with the desulfurizing agent into the housing. The housing includes a fuel preheating portion 612 that accommodates heat transfer portions 90, 91, 92 that transfer the heat from a heated fluid led into the housing by the heating flow path portion to a raw material for reforming on the upstream of the position where each of the desulfurizing agent filling portion is provided in the flow direction of the reforming raw material flowing inside the housing.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a desulfurizer.

Background Art

[0002] Conventionally, a fuel cell system including a desulfurizer that removes sulfur components in a reforming raw material, a reformer that generates anode gas from the reforming raw material from which sulfur components have been removed, and a fuel cell that generates power using the anode gas and cathode gas is known (see, for example, Patent Document 1). Inside the desulfurizer described in Patent Document 1, a catalyst and a desulfurizing agent that chemically react with sulfur components in the reforming raw material are accommodated. This desulfurizing agent takes in and removes hydrogen sulfide converted from a sulfur compound by the catalyst, and exhibits an excellent desulfurizing effect at a high temperature such as 200°C to 300°C. Therefore, Patent Document 1 describes that the desulfurizer is disposed at a position adjacent to the fuel cell module and the desulfurizer is heated using heat radiation from the fuel cell module.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when a reforming raw material having a temperature lower than the temperature of the desulfurizing agent accommodated inside the desulfurizer flows into the desulfurizer, the desulfurizing agent is cooled by the reforming raw material and its temperature decreases. As a result, if the temperature of the desulfurizing agent is cooled to a temperature lower than the temperature at which an excellent desulfurizing effect is exhibited, the amount of sulfur components that can be removed by the desulfurizing agent may decrease. And when the amount of sulfur components that can be removed by the desulfurizing agent decreases, the desulfurization ability of the desulfurizer decreases.

[0005] Therefore, it is desirable that the reforming raw material that chemically reacts with the desulfurizing agent is not at a lower temperature than the desulfurizing agent. However, Patent Document 1 does not describe a means of heating the reforming raw material that flows into the desulfurizer, making it difficult to avoid a decrease in the amount of sulfur components that the desulfurizing agent can remove due to the influx of reforming raw material that is at a lower temperature than the desulfurizing agent.

[0006] In view of the above points, this disclosure aims to provide a desulfurizer capable of improving desulfurization capacity. [Means for solving the problem]

[0007] The invention described in claim 1 is, A desulfurizer for removing sulfur components contained in reforming raw materials, A housing (60) through which the reforming raw material flows, and which is filled with a desulfurizing agent filling section (613, 615) that removes the sulfur component of the reforming raw material, The device includes a heating channel section (83) that guides a heating fluid into the housing to heat the desulfurizing agent by exchanging heat with the desulfurizing agent, The casing has a fuel preheating section (612) upstream of the position where the desulfurizing agent filling section is located in the flow direction of the reforming raw material flowing inside the casing, which houses heat transfer sections (90, 91, 92) that transfer heat from the heated fluid introduced into the casing by the heating channel section to the reforming raw material. death, The heat transfer section includes a plate-shaped plate section (91) through which a heating channel section is connected and which has a plate surface oriented in a direction intersecting the flow direction of the reforming raw material when it flows into the fuel preheating section, forming a fuel preheating channel forming section (90, 91, 92) through which the reforming raw material flows in the fuel preheating section, thereby increasing the amount of heat transferred from the fuel preheating channel forming section to the reforming raw material by changing the flow direction of the reforming raw material when it flows into the fuel preheating section. The plate section has fuel flow holes (912) through which the reforming material flows. .

[0008] According to this method, even if the fuel flowing into the desulfurizer is at a lower temperature than the desulfurizing agent, the reforming material before it flows into the desulfurizing agent packing section can be heated by transferring heat from the heating fluid to the reforming material via the heat transfer section. Therefore, when the reforming material flows into the desulfurizing agent packing section, the decrease in the temperature of the desulfurizing agent packed in the desulfurizing agent packing section due to the reforming material can be suppressed, thus avoiding a decrease in the amount of sulfur components that the desulfurizing agent can adsorb. Consequently, the desulfurization capacity of the desulfurizer can be improved.

[0009] The reference numerals in parentheses attached to each component indicate an example of the correspondence between that component and the specific components described in the embodiments described later. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of the fuel cell system according to the first embodiment. [Figure 2] This is a cross-sectional view of the desulfurizer according to the first embodiment. [Figure 3] This is a partial cross-sectional view of a desulfurizer according to the first embodiment. [Figure 4] This is a cross-sectional view of the fuel preheating section according to the first embodiment. [Figure 5] This diagram shows the flow of fuel through the fuel preheating section according to the first embodiment. [Figure 6] This is a schematic diagram of the external appearance of a desulfurizer according to the second embodiment. [Figure 7] This is an enlarged view of section VII shown in Figure 6. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described below with reference to the drawings. In the following embodiments, parts that are the same as or equivalent to those described in the prior embodiments will be denoted by the same reference numerals, and their descriptions may be omitted. Also, if only a part of a component is described in an embodiment, the components described in the prior embodiments can be applied to the other parts of that component. The following embodiments can be partially combined with each other, even if not explicitly stated, as long as it does not impede the combination.

[0012] (First Embodiment) This embodiment will be described with reference to FIGS. 1 to 5. As shown in FIG. 1, the desulfurizer 32 of this embodiment is used in the fuel cell system 1. This fuel cell system 1 includes a solid oxide fuel cell 10. The solid oxide fuel cell 10 is generally also called SOFC (abbreviation for Solid Oxide Fuel Cell), and its operating temperature is high (for example, 500°C to 1000°C).

[0013] The fuel cell 10 has a stack structure in which a plurality of power generation cells that output electric energy by the electrochemical reaction of fuel gas and oxidant gas (oxygen in air in this example) are stacked. Note that the shape of the power generation cell may be either flat plate type or cylindrical type.

[0014] Although not shown, the power generation cell includes a solid oxide electrolyte, an air electrode (that is, a cathode), and a fuel electrode (that is, an anode). The power generation cell uses hydrogen and carbon monoxide generated by reforming city gas (that is, gas mainly composed of methane), which is a hydrocarbon-based fuel, as fuel gas. Note that as long as the fuel used is a hydrocarbon-based gas, a gas other than city gas may be adopted.

[0015] The fuel cell 10 outputs electric energy by the electrochemical reaction of hydrogen and oxygen shown in the following reaction formulas F1 and F2.

[0016] (Fuel electrode) 2H2 + 2O2 - → 2H2O + 4e - …(F1)

[0017] (Air electrode) O2 + 4e - → 2O2 - …(F2) Also, the fuel cell 10 outputs electric energy by the electrochemical reaction of carbon monoxide and oxygen shown in the following reaction formulas F3 and F4.

[0018] (Fuel electrode) 2CO + 2O2 - → 2CO2 + 4e - …(F3)

[0019] (Air electrode) O2 + 4e - →2O2 - …(F4) Although not shown in the diagram, the fuel cell 10 is located inside a heat-insulating housing along with the air preheater 22, desulfurizer 32, reformer 33, combustor 53, etc., which will be described later. The fuel cell 10 is warmed up by the combustor 53, which will be described later, when starting up. In the fuel cell system 1, the equipment located inside the housing constitutes the hot module HM.

[0020] The fuel cell 10 has an air supply channel 20, which is an air circulation path, connected to its air inlet 10a. The air supply channel 20 is made up of piping and the like. The air supply channel 20 is equipped with a pressure blower 21 that pumps air to the fuel cell 10 and an air preheater 22 that heats the air supplied to the fuel cell 10.

[0021] The pressure blower 21 is an oxidizer pump that draws in air from outside the fuel cell system 1 and supplies it to the fuel cell 10. The pressure blower 21 discharges the drawn-in air toward the downstream side of the air supply passage 20. The pressure blower 21 is an electrically operated blower whose operation is controlled by a control signal from a control device (not shown).

[0022] The air preheater 22 is a heat exchanger that heats the air supplied from the pressurized blower 21 by exchanging heat with the exhaust gas generated in the combustor 53, which will be described later. The air preheater 22 is provided to reduce the temperature difference between the air supplied to the fuel cell 10 and the fuel gas, thereby improving the power generation efficiency of the fuel cell 10.

[0023] On the other hand, the fuel cell 10 has a fuel supply channel 30, which is a flow path for fuel and fuel gas, connected to the fuel inlet 10b. The fuel supply channel 30 is made up of pipes and the like. The fuel supply channel 30 is equipped with a fuel pump 31, a desulfurizer 32, an ejector 56, and a reformer 33, in order from the upstream side.

[0024] The fuel pump 31 is a pump that supplies fuel, which is a reforming material supplied from an external source, toward the fuel cell 10. The fuel pump 31 discharges the sucked-in fuel toward the downstream side of the fuel supply passage 30. The fuel pump 31 is an electric pump whose operation is controlled by a control signal from a control device (not shown).

[0025] The desulfurizer 32 is a device for removing sulfur components contained in the fuel supplied from the fuel pump 31. The desulfurizer 32 in this embodiment employs a hydrogenation desulfurizer that removes sulfur components from the reforming raw material by reacting the sulfur components contained in the fuel with hydrogen. As will be described later, the desulfurizer 32 in this embodiment is configured by being filled with a desulfurizing agent. As the desulfurizing agent, for example, a CuZn-based catalyst that has both the function of converting sulfur compounds into hydrogen sulfide and the function of adsorbing hydrogen sulfide may be used.

[0026] The shape of the desulfurizing agent is not particularly limited, and for example, granular, columnar (e.g., cylindrical), fibrous, honeycomb, or crushed forms can be used. In this embodiment, a cylindrical particulate desulfurizing agent with an outer diameter and height of 3 mm is used. The desulfurizing agent in the desulfurizer 32 is heated by heat exchange with the exhaust gas generated in the combustor 53, as described later.

[0027] The desulfurizing agent is not limited to this, and may, for example, consist of a CoMo-based catalyst that converts sulfur compounds in the fuel into hydrogen sulfide, and at least one of a ZnO-based catalyst and a CuZn-based catalyst, which are adsorbents that adsorb the converted hydrogen sulfide. Details of the desulfurizer 32 will be described later.

[0028] The reformer 33 uses the steam vaporized in the water evaporator 42 to reform the fuel supplied from the fuel pump 31 and produce fuel gas. The reformer 33 is composed of a steam reforming catalyst containing, for example, a precious metal such as rhodium or ruthenium.

[0029] Specifically, the reformer 33 heats the mixed gas, which is a mixture of fuel and steam, by heat exchange with the exhaust gas generated in the combustor 53 (described later), and generates fuel gas (hydrogen, carbon monoxide) through the reforming reaction shown in reaction equation F5 and the shift reaction shown in reaction equation F6 below.

[0030] CH4 + H2O → CO + H2…(F5) CO + H2O → CO2 + H2…(F6) Here, steam reforming in the reformer 33 is an endothermic reaction and has the characteristic that the reforming rate improves under high-temperature conditions. For this reason, the reformer 33 may be arranged around the fuel cell 10 so that it can absorb the heat (radiant heat) released into the surroundings when the fuel cell 10 generates electricity.

[0031] Furthermore, a water supply channel 40 is connected to the fuel supply channel 30 between the desulfurizer 32 and the reformer 33. A water pump 41 and a water evaporator 42 are provided in the water supply channel 40.

[0032] The water pump 41 is a pump that supplies water to the water evaporator 42 from outside the fuel cell system 1. The water pump 41 discharges the water it draws in toward the downstream side of the water supply channel 40. The water pump 41 is an electric pump whose operation is controlled by a control signal from a control device (not shown).

[0033] The water evaporator 42 has an evaporation function that converts water from the water pump 41 into water vapor (i.e., gas). Specifically, the water evaporator 42 is composed of an evaporator that evaporates water supplied from the water pump 41 by exchanging heat with the exhaust gas produced in the combustor 53.

[0034] Furthermore, an ejector 56 is provided in the fuel supply channel 30 downstream of the point where the water supply channel 40 is connected, between the desulfurizer 32 and the reformer 33. The ejector 56 uses the raw fuel upstream of the reformer 33 as a driving flow to draw in the off-gas fuel flowing through the recycling channel 55 (described later) and supplies it to the reformer 33 together with the raw fuel.

[0035] Specifically, the ejector 56 has a nozzle section 561 for injecting fluid, a suction section 562 for drawing fluid from the outlet side of the fuel cell 10, and a discharge section 563 for mixing the fluid injected from the nozzle section 561 and the fluid drawn in from the suction section 562 and discharging it toward the reformer 33.

[0036] The nozzle section 561 has a throttling structure capable of spraying fluid. The nozzle section 561 is configured as a fixed throttling structure with a fixed throttling opening. The discharge section 563 has a flow path cross-sectional area that expands downstream so that the fluid from the nozzle section 561 and the fluid from the suction section 562 are mixed and then pressurized. The nozzle section 561 may also be configured as a variable throttling structure with a changeable throttling opening.

[0037] The suction section 562 of the ejector 56 is configured to draw fluid from the outlet side of the fuel cell 10 by utilizing the negative pressure on the outlet side of the nozzle section 561. Specifically, a recycling channel 55 branching off from the fuel discharge pipe 52 is connected to the suction section 562 so that the fluid flowing through the fuel discharge pipe 52, which will be described later, is drawn in.

[0038] Furthermore, an assist channel 34 is connected to the fuel supply channel 30, which returns a portion of the fuel gas flowing downstream of the reformer 33 in the fuel supply channel 30 as circulating gas to the upstream of the fuel pump 31 in the fuel supply channel 30. One end of the assist channel 34 is connected downstream of the reformer 33 in the fuel supply channel 30, and the other end is connected upstream of the fuel pump 31 in the fuel supply channel 30.

[0039] The assist channel 34 is equipped with a condenser 35 and an assist flow control valve 36. Furthermore, a water evaporator 42 is connected to the assist channel 34 upstream of the condenser 35.

[0040] The condenser 35 condenses the water contained in the fuel gas flowing through the assist channel 34. Specifically, the condenser 35 separates the fuel gas into liquid water and gas by condensing the fuel gas containing water vapor supplied as it passes through the water evaporator 42 into liquid water.

[0041] The assist flow control valve 36 is a flow control member that adjusts the flow rate of fuel gas flowing through the assist passage 34. The assist flow control valve 36 is composed of a solenoid valve whose operation is controlled by a control signal from a control device (not shown).

[0042] Here, the ejector 56 has the characteristic that the flow rate of the suction fluid drawn in from the suction section 562 increases as the mass flow rate of the fluid flowing into the nozzle section 561 as the driving flow increases. Therefore, by increasing the mass flow rate of the fluid flowing into the nozzle section 561 of the ejector 56, it is possible to increase the suction flow rate of the off-gas fuel drawn in from the suction section 562.

[0043] For example, by opening the assist flow control valve 36 to increase the circulating gas flowing through the assist passage 34, the drive flow of the ejector 56 can be increased without increasing the amount of fuel supplied from outside the system.

[0044] Furthermore, the fuel cell 10 is connected to an off-gas pipe 50 through which off-gas discharged from the fuel cell 10 flows. Specifically, the fuel cell 10 is connected to an air outlet section 10c through which oxidizer off-gas discharged from the fuel cell 10 flows. In addition, the fuel cell 10 is connected to a fuel outlet section 10d through a fuel discharge pipe 52 through which fuel off-gas discharged from the fuel cell 10 flows.

[0045] Furthermore, a combustor 53 is connected to the off-gas piping 50. The combustor 53 generates exhaust gas that raises the temperature of the reformer 33, air preheater 22, water evaporator 42, and desulfurizer 32 by burning fuel off-gas. For example, when the fuel cell 10 is generating electricity, the combustor 53 generates exhaust gas that raises the temperature of each component of the fuel cell system 1 by burning a mixed gas, which is a mixture of oxidizer off-gas and fuel off-gas, as a combustible gas. Although not shown, the combustor 53 has a burner for burning fuel off-gas. In the combustor 53, the fuel off-gas is burned by ignition of the burner, generating high-temperature exhaust gas. In this embodiment, the desulfurizing agent generated by the combustor 53 corresponds to the heating fluid that heats the desulfurizing agent.

[0046] The combustor 53 is connected to an exhaust gas passage 54 through which high-temperature exhaust gas flows. To effectively utilize the heat of the exhaust gas flowing through the exhaust gas passage 54, the following components are connected in order from upstream: reformer 33, air preheater 22, water evaporator 42, and desulfurizer 32. The order in which the exhaust gas flows to each component may be changed according to the amount of heat required by each component.

[0047] Furthermore, a combustion catalyst 57 is provided in the exhaust gas passage 54. The combustion catalyst 57 burns the off-fuel and off-air flowing through the exhaust gas passage 54. The combustion catalyst 57 is located between the reformer 33 and the air preheater 22 in the exhaust gas passage 54. However, the combustion catalyst 57 is not limited to this location and may be connected to other positions in the exhaust gas passage 54.

[0048] Although not shown in the diagram, an oxidation catalyst is arranged inside the combustion catalyst 57. The combustion catalyst 57 generates combustion heat through the oxidation reaction of off-fuel and off-air in the oxidation catalyst. This combustion catalyst 57 is configured to burn exhaust gas without generating a flame, for example, like a catalytic converter that purifies automobile exhaust gases.

[0049] Next, the details of the desulfurizer 32 will be explained with reference to Figures 2 to 4. The desulfurizer 32 has a housing 60 filled with a desulfurizing agent that removes sulfur components from the fuel. The housing 60 is a container that forms the outer shell of the desulfurizer 32. The desulfurizer 32 is formed so that fuel and exhaust gas can flow through the inside of the housing 60.

[0050] Furthermore, the desulfurizer 32 has a fuel inlet pipe 71 that guides fuel into the interior of the housing 60 and a fuel outlet pipe 72 that guides the fuel introduced into the interior of the housing 60 to the outside of the desulfurizer 32. In addition, the desulfurizer 32 has an exhaust gas inlet pipe 81 that guides exhaust gas into the interior of the housing 60 and an exhaust gas outlet pipe 82 that guides the exhaust gas introduced into the interior of the housing 60 to the outside of the desulfurizer 32.

[0051] As shown in Figures 2 to 4, the housing 60 is a hollow cylindrical shape and contains a housing space 61 on its inside that is filled with a desulfurizing agent. The housing 60 is positioned such that its axis CL extends along the direction in which gravity acts (i.e., the vertical direction). In this embodiment, the direction extending along the axis CL of the housing 60 is called the axial direction DRa, the direction passing through the axis CL of the housing 60 and perpendicular to the axial direction DRa is called the radial direction DRr, and the direction along the circle centered on the axis CL of the housing 60 is called the circumferential direction DRc.

[0052] The housing 60 has an outer periphery 62 surrounding the circumferential DRc of the housing space 61, a one-side cover 63 that closes one side of the axial DRa of the housing space 61, and a other-side cover 64 that closes the other side of the axial DRa of the housing space 61. That is, the housing space 61 is surrounded by the outer periphery 62, the one-side cover 63, and the other-side cover 64. The outer periphery 62 is the part of the housing 60 that surrounds the axis CL. The outer periphery 62 is formed along the axial DRa.

[0053] On the other side cover 64, an exhaust gas inlet 641 is formed for introducing exhaust gas into the housing 60, and an exhaust gas inlet pipe 81 is connected to this exhaust gas inlet 641. On the other side cover 63, an exhaust gas outlet 631 is formed for guiding the exhaust gas introduced into the housing 60 to the outside of the housing 60, and an exhaust gas outlet pipe 82 is connected to this exhaust gas outlet 631. The exhaust gas outlet 631 has a larger opening area compared to the exhaust gas inlet 641. In other words, the exhaust gas outlet 631 has a larger inner diameter compared to the exhaust gas inlet 641. The exhaust gas outlet pipe 82 connected to the exhaust gas outlet 631 has a larger inner diameter compared to the exhaust gas inlet pipe 81 connected to the exhaust gas inlet 641. In this embodiment, the exhaust gas inlet 641 corresponds to the heating fluid inlet, and the exhaust gas outlet 631 corresponds to the heating fluid outlet.

[0054] The containment space 61 is divided into multiple spaces by multiple partition members. Specifically, the interior of the containment space 61 is divided into six spaces aligned along the axial DRa by thin, disc-shaped members, each having a plate thickness direction in the axial DRa direction. The members that partition the interior of the containment space 61 are arranged in the following order from one side to the other along the axial DRa: exhaust gas collection plate 65, upstream desulfurizing agent support plate 66, filling section partition plate 67, downstream desulfurizing agent support plate 68, and exhaust gas branching plate 69.

[0055] The exhaust gas collection plate 65, the upstream desulfurizing agent support plate 66, the filling section partition plate 67, the downstream desulfurizing agent support plate 68, and the exhaust gas branching plate 69 are arranged so that their respective centers are located on the axis CL of the housing 60. Furthermore, the outer diameters of the exhaust gas collection plate 65, the upstream desulfurizing agent support plate 66, the filling section partition plate 67, the downstream desulfurizing agent support plate 68, and the exhaust gas branching plate 69 are approximately equal to the inner diameter of the outer circumference 62, and the outer edges of each abut against the inner circumferential surface 621 of the outer circumference 62.

[0056] The containment space 61 is then divided into six spaces by these five partition members: the exhaust gas outlet tank 611, the fuel preheating section 612, the upstream filling section 613, the fuel straightening section 614, the downstream filling section 615, and the exhaust gas inlet tank 616. The exhaust gas outlet tank 611, the fuel preheating section 612, the upstream filling section 613, the fuel straightening section 614, the downstream filling section 615, and the exhaust gas inlet tank 616 are arranged in this order from one side to the other in the axial direction DRa.

[0057] The upstream filling section 613 and the downstream filling section 615 are desulfurizing agent filling sections into which desulfurizing agent is filled. The upstream filling section 613 and the downstream filling section 615 are arranged side by side in the axial direction DRa via the fuel straightening section 614. Furthermore, the axial direction DRa of the upstream filling section 613 and the downstream filling section 615 are equal in magnitude. In addition, the axial direction DRa of the upstream filling section 613 and the downstream filling section 615 is larger than that of the fuel straightening section 614.

[0058] The upstream filling section 613 is formed on one side of the axial DRa of the fuel rectifier section 614 and is surrounded by the outer periphery 62, the upstream desulfurizer support plate 66, and the filling section partition plate 67. The entire space of the upstream filling section 613 is filled with desulfurizer. The desulfurizer filling the upstream filling section 613 is supported by the upstream desulfurizer support plate 66.

[0059] The downstream filling section 615 is formed on the other side of the axial DRa of the fuel rectifier section 614 and is surrounded by the outer periphery 62, the downstream desulfurizer support plate 68, and the exhaust gas branch plate 69. The entire space of the downstream filling section 615 is filled with desulfurizer. The desulfurizer filling the downstream filling section 615 is supported by the downstream desulfurizer support plate 68.

[0060] As shown in Figure 3, the upstream desulfurizing agent support plate 66, the filling section partition plate 67, and the downstream desulfurizing agent support plate 68 have punched holes 661, 671, and 681 that connect the upstream filling section 613, the fuel straightening section 614, and the downstream filling section 615, respectively. The punched holes 661 formed in the upstream desulfurizing agent support plate 66 are formed over almost the entire area of ​​the upstream desulfurizing agent support plate 66. The punched holes 681 formed in the downstream desulfurizing agent support plate 68 are formed over almost the entire area of ​​the downstream desulfurizing agent support plate 68. In contrast, the punched holes 671 formed in the filling section partition plate 67 are formed around the center of the filling section partition plate 67, and not around the outer edge of the filling section partition plate 67.

[0061] The diameters of the punched holes 661, 671, and 681 formed in the upstream desulfurizing agent support plate 66, the filling section partition plate 67, and the downstream desulfurizing agent support plate 68 are smaller than the desulfurizing agent particles and are formed to allow fuel gas to pass through.

[0062] In other words, the upstream filling section 613, the fuel straightening section 614, and the downstream filling section 615 are prevented from receiving the desulfurizing agent through the punched holes 661, 671, and 681 formed in the upstream desulfurizing agent support plate 66, the filling section partition plate 67, and the downstream desulfurizing agent support plate 68, respectively. In contrast, the fuel gas introduced into the housing 60 is allowed to pass through the upstream filling section 613, the fuel straightening section 614, and the downstream filling section 615 through the punched holes 661, 671, and 681 formed in the upstream desulfurizing agent support plate 66, the filling section partition plate 67, and the downstream desulfurizing agent support plate 68, respectively.

[0063] The fuel rectifier section 614 is a part that rectifies the flow of fuel gas as it flows from the upstream filling section 613 to the downstream filling section 615 after being introduced into the housing 60. Inside the fuel rectifier section 614, there is a thin, disc-shaped rectifier plate 6141 with a thickness in the axial direction DRa. The rectifier plate 6141 is positioned so that its center is located on the axis CL of the housing 60.

[0064] The rectifier plate 6141 is formed with an outer diameter smaller than the inner diameter of the outer circumference 62. As a result, a gap is formed between the outer edge of the rectifier plate 6141 and the inner surface 621 of the outer circumference 62. Fuel flowing from the upstream filling section 613 toward the downstream filling section 615 can then flow through the gap between the outer edge of the rectifier plate 6141 and the inner surface 621 of the outer circumference 62. Hereinafter, the flow path in the gap between the outer edge of the rectifier plate 6141 and the inner surface 621 of the outer circumference 62 will also be referred to as the rectifier flow path 6142.

[0065] Furthermore, the outer diameter of the rectifier plate 6141 is formed to be large enough to cover all of the punched holes 671 formed in the filling section partition plate 67 in the axial direction DRa. In other words, the outer diameter of the rectifier plate 6141 is formed to be larger than the area in the filling section partition plate 67 where the punched holes 671 are formed. To put it another way, the area in the filling section partition plate 67 where the punched holes 671 are provided is covered by the rectifier plate 6141 in the axial direction DRa. As a result, the fuel introduced into the fuel rectifier section 614 through the punched holes 671 of the filling section partition plate 67 collides with the rectifier plate 6141. The rectifier plate 6141 is a component that obstructs the flow of fuel introduced into the fuel rectifier section 614 through the punched holes 671 of the filling section partition plate 67.

[0066] Furthermore, the housing 60 is provided with a plurality of exhaust gas flow pipes 83 through which the exhaust gas introduced into the housing 60 via the exhaust gas inlet pipe 81 flows. The exhaust gas flow pipes 83 are piping members that guide the exhaust gas that heats the desulfurizing agent into the housing 60. Each of the plurality of exhaust gas flow pipes 83 is a piping member that extends along the axial direction DRa and is arranged from the exhaust gas outlet tank 611 to the exhaust gas inlet tank 616. The exhaust gas flow pipes 83 are made of any metal material with high thermal conductivity, such as stainless steel, or an alloy material containing the same. Note that the metal constituting the exhaust gas flow pipes 83 is not limited to stainless steel, but may be a material with high thermal conductivity, such as aluminum. In this embodiment, the exhaust gas flow pipes 83 correspond to the heating flow path section.

[0067] Each of the multiple exhaust gas flow pipes 83 has one end of its axial DRa connected to the exhaust gas aggregation plate 65, and the other end of its axial DRa connected to the exhaust gas branching plate 69. Each of the multiple exhaust gas flow pipes 83 passes through the baffle plate 90, the upstream desulfurizing agent support plate 66, the filling section partition plate 67, the rectifier plate 6141, and the downstream desulfurizing agent support plate 68, which will be described later. In other words, each of the multiple exhaust gas flow pipes 83 straddles the fuel preheating section 612, the upstream filling section 613, the fuel rectifier section 614, and the downstream filling section 615.

[0068] As shown in Figure 3, the exhaust gas branching plate 69 has multiple communication holes 691 formed therein, which connect the other side of the axial DRa of the exhaust gas flow pipe 83 to the exhaust gas inlet tank 616. The other side of the axial DRa of the exhaust gas flow pipe 83 is connected to each of these multiple communication holes 691 formed in the exhaust gas branching plate 69.

[0069] Furthermore, the exhaust gas collection plate 65 has multiple communication holes (not shown) that connect one side of the axial DRa of the exhaust gas flow pipe 83 to the exhaust gas outlet tank 611. One side of the axial DRa of the exhaust gas flow pipe 83 is connected to each of these communication holes formed in the exhaust gas collection plate 65.

[0070] As a result, the exhaust gas inlet tank 616 and the exhaust gas outlet tank 611 are connected via a plurality of exhaust gas flow pipes 83. Each of the plurality of exhaust gas flow pipes 83 is arranged so that they are approximately uniformly distributed throughout the entire containment space 61, with approximately equal distances between them. However, the distances between the plurality of exhaust gas flow pipes 83 do not need to be equal; some may be different.

[0071] The exhaust gas inlet tank 616 is a space for branching the exhaust gas introduced into the housing 60 via the exhaust gas inlet piping 81 into a plurality of exhaust gas flow pipes 83, and is in communication with the exhaust gas inlet piping 81. The exhaust gas introduced into the exhaust gas inlet tank 616 is branched into a plurality of exhaust gas flow pipes 83 connected to the exhaust gas branching plate 69, flows from one side to the other in the axial direction DRa, and is discharged into the exhaust gas outlet tank 611.

[0072] The exhaust gas outlet tank 611 is a space for collecting the exhaust gas flowing through each of the multiple exhaust gas flow pipes 83, and is connected to one side of the axial DRa of the exhaust gas flow pipes 83. The exhaust gas outlet tank 611 is connected to the exhaust gas outlet piping 82 and collects the exhaust gas discharged from the multiple exhaust gas flow pipes 83. The exhaust gas collected in the exhaust gas outlet tank 611 is discharged to the outside of the desulfurizer 32 via the exhaust gas outlet piping 82.

[0073] In this manner, the exhaust gas introduced into the exhaust gas inlet tank 616 via the exhaust gas inlet pipe 81 is branched into multiple exhaust gas flow pipes 83. The exhaust gas introduced into each of the multiple exhaust gas flow pipes 83 flows from one side to the other in the axial direction of DRa, is collected in the exhaust gas outlet tank 611, and is discharged to the outside of the desulfurizer 32 via the exhaust gas outlet pipe 82.

[0074] Furthermore, a fuel outlet pipe 72 is connected to the exhaust gas branching plate 69. The fuel outlet pipe 72 penetrates the exhaust gas branching plate 69 and protrudes into the downstream filling section 615, communicating with the downstream filling section 615. Also, as shown in Figure 4, a fuel inlet pipe 71 is connected to the exhaust gas consolidating plate 65. The fuel inlet pipe 71 penetrates the exhaust gas consolidating plate 65 and protrudes into the fuel preheating section 612, communicating with the fuel preheating section 612. As a result, the fuel inlet pipe 71 and the fuel outlet pipe 72 are in communication via the fuel preheating section 612, the upstream filling section 613, the fuel straightening section 614, and the downstream filling section 615.

[0075] Therefore, the fuel introduced into the fuel preheating section 612 via the fuel inlet pipe 71 flows from one side of the axial DRa to the other, crossing the upstream filling section 613, the fuel straightening section 614, and the downstream filling section 615, and is discharged to the outside of the desulfurizer 32 via the fuel outlet pipe 72.

[0076] The fuel preheating section 612 is a space for heating the fuel introduced into the fuel preheating section 612 via the fuel inlet pipe 71. The fuel preheating section 612 is located upstream of the upstream filling section 613 and the downstream filling section 615 in the direction of fuel flow within the housing 60. Inside the fuel preheating section 612, a thin, disc-shaped baffle plate 90 with a thickness direction in the axial direction DRa is provided.

[0077] The baffle plate 90 has a plate surface that intersects the direction of fuel flow (in this embodiment, the direction toward the other side in the axial direction DRa) into the fuel preheating section 612. Specifically, the baffle plate 90 has a plate surface that is perpendicular to the axial direction DRa. In this embodiment, the baffle plate 90 has a plate surface that is perpendicular to the axial direction DRa. The baffle plate 90 heats the fuel introduced into the fuel preheating section 612 by transferring the temperature of the high-temperature exhaust gas flowing through the exhaust gas flow pipe 83 to the fuel.

[0078] The baffle plates 90 are arranged within a predetermined range of the space extending in the axial direction DRa formed by the fuel preheating section 612. In this embodiment, the baffle plates 90 are arranged on one side of the space formed by the fuel preheating section 612, approximately from the center of the axial direction DRa. The range in which the baffle plates 90 are arranged is not limited to this, and may be greater or less than the range in this embodiment, depending on the amount of fuel heated when introduced into the fuel preheating section 612. In this embodiment, the number of baffle plates 90 is set so that the fuel introduced into the fuel preheating section 612 can be heated to a temperature similar to that of the exhaust gas introduced into the desulfurizer 32. The baffle plates 90 include a large-diameter baffle plate 91 and a small-diameter baffle plate 92 with a smaller outer diameter than the large-diameter baffle plate 91.

[0079] The large-diameter baffle plates 91 and the small-diameter baffle plates 92 are arranged alternately along the axial direction DRa. The centers of the large-diameter baffle plates 91 and the small-diameter baffle plates 92 are positioned on the axis CL of the housing 60. The large-diameter baffle plates 91 and the small-diameter baffle plates 92 are joined to the exhaust gas flow pipe 83, which penetrates them, by a joining method such as welding. The large-diameter baffle plates 91 and the small-diameter baffle plates 92 are made of any metal material with high thermal conductivity, such as stainless steel, or an alloy material containing such material. In this embodiment, the large-diameter baffle plates 91 and the small-diameter baffle plates 92 function as heat transfer sections, transferring heat from the exhaust gas flowing through the exhaust gas flow pipe 83 to the fuel flowing through the fuel preheating section 612. Note that the metals constituting the large-diameter baffle plates 91 and the small-diameter baffle plates 92 are not limited to stainless steel; for example, they may be made of a material with high thermal conductivity, such as aluminum.

[0080] The adjacent large-diameter baffle plates 91 and small-diameter baffle plates 92 are arranged with a predetermined gap between them so that combustion can be introduced into the gap between the large-diameter baffle plate 91 and the small-diameter baffle plate 92. Fuel introduced into the fuel preheating section 612 is introduced into the gap passage formed between the adjacent large-diameter baffle plate 91 and the small-diameter baffle plate 92. In other words, the large-diameter baffle plate 91 and the small-diameter baffle plate 92 are fuel preheating passage forming sections that form the fuel through which the fuel introduced into the fuel preheating section 612 flows. Hereinafter, the gap passages formed between each of the multiple large-diameter baffle plates 91 and the multiple small-diameter baffle plates 92 will also be referred to as inter-baffle plate passages 93.

[0081] The large-diameter baffle plate 91 has an outer diameter approximately equal to the inner diameter of the outer circumference 62, and has a unidirectional bend portion 911 formed by bending it toward one side in the axial direction DRa at its outer edge. This unidirectional bend portion 911 of the large-diameter baffle plate 91 abuts against the inner circumferential surface 621 of the outer circumference 62. The large-diameter baffle plate 91 also has a fuel flow hole 912 through which the fuel introduced into the fuel preheating section 612 flows. The fuel flow hole 912 penetrates the large-diameter baffle plate 91 in the axial direction DRa at its center, and is formed to be larger than the outer diameter of the exhaust gas flow pipe 83. As a result, a gap is formed between the inner circumference of the fuel flow hole 912 of the large-diameter baffle plate 91 and the outer wall of the exhaust gas flow pipe 83 that penetrates the fuel flow hole 912. Furthermore, the fuel introduced into the fuel preheating section 612 can flow through the gap provided between the inner circumference of the fuel flow hole 912 and the outer wall of the exhaust gas flow pipe 83.

[0082] The small-diameter baffle plate 92 is formed with an outer diameter smaller than the inner diameter of the outer periphery 62. As a result, a gap is formed between the outer edge of the small-diameter baffle plate 92 and the inner circumferential surface 621 of the outer periphery 62. The fuel introduced into the fuel preheating section 612 can then flow through the gap formed between the outer edge of the small-diameter baffle plate 92 and the inner circumferential surface 621 of the outer periphery 62. Hereinafter, the flow path in the gap between the outer edge of the small-diameter baffle plate 92 and the inner circumferential surface 621 of the outer periphery 62 will also be referred to as the outer periphery flow path 921.

[0083] Furthermore, an exhaust gas flow pipe 83 passes through the center of the small-diameter baffle plate 92. The small-diameter baffle plate 92 has a bent portion 922 formed by bending toward the other side in the axial direction DRa at the point where the exhaust gas flow pipe 83, which passes through the center of the small-diameter baffle plate 92, is joined. This bent portion 922 of the small-diameter baffle plate 92 is joined to the outer wall of the exhaust gas flow pipe 83. In this embodiment, the large-diameter baffle plate 91 corresponds to the first plate portion, and the small-diameter baffle plate 92 corresponds to the second plate portion.

[0084] Next, the basic operation of the fuel cell system 1 will be described. When the operating switch (not shown) is turned on, the fuel cell system 1 performs a power generation process in which electrical energy is output from the fuel cell 10.

[0085] In this power generation process, for example, the pressurized blower 21, fuel pump 31, and water pump 41 are controlled so that an appropriate amount of oxidizer gas and fuel gas is supplied to the fuel cell 10 for power generation.

[0086] The fuel discharged from the fuel pump 31 has its sulfur components removed in the desulfurizer 32. Specifically, the fuel discharged from the fuel pump 31 is introduced into the housing 60 via the fuel inlet pipe 71 in the desulfurizer 32. The fuel introduced into the housing 60 then flows in the order of fuel preheating section 612, upstream filling section 613, fuel straightening section 614, and downstream filling section 615, and is discharged to the outside of the desulfurizer 32 via the fuel outlet pipe 72. As the fuel flows through the desulfurizer 32 in this manner, the sulfur components are removed by the desulfurizing agent packed in the upstream filling section 613 and the downstream filling section 615, respectively, as it passes through them.

[0087] The fuel from which sulfur components have been removed in the desulfurizer 32 is then mixed with water vapor vaporized in the water evaporator 42 before flowing into the reformer 33. In the reformer 33, when the mixed gas of fuel and water vapor is supplied, fuel gas (hydrogen, carbon monoxide) is produced by the reactions shown in the reaction equations F5 and F6 above. When the assist flow control valve 36 is closed, the fuel gas produced in the reformer 33 flows entirely into the fuel cell 10 without flowing into the assist flow path 34. On the other hand, when the assist flow control valve 36 is open, a portion of the fuel gas produced in the reformer 33 is guided to the reformer 33 via the assist flow path 34 and then via the fuel supply flow path 30, while the remainder flows into the fuel cell 10. The fuel gas flowing through the assist flow path 34 has its water content condensed by the condenser 35.

[0088] Furthermore, the oxidizing gas blown out from the pressurized blower 21 flows into the air preheater 22 and is heated through heat exchange with the exhaust gas. The air that has passed through the air preheater 22 then flows into the fuel cell 10.

[0089] When the fuel cell 10 is supplied with oxidizer gas and fuel gas, it outputs electrical energy through the reactions shown in the reaction equations F1 to F4 described above. During this process, the fuel cell 10 discharges off-gas fuel and off-gas air.

[0090] The off-gas air discharged from the fuel cell 10 is led to the combustor 53 via the air discharge pipe 51. The off-gas fuel discharged from the fuel cell 10 flows into the fuel discharge pipe 52, a portion of which is drawn in through the recycling channel 55 and into the suction section 562 of the ejector 56, while the remainder is led to the combustor 53.

[0091] The off-gas fuel and off-gas air introduced to the combustor 53 are then burned as combustible gas in the combustor 53 to produce high-temperature exhaust gas. As the high-temperature exhaust gas produced in the combustor 53 flows through the exhaust gas flow path 54, it passes through the reformer 33, air preheater 22, water evaporator 42, and desulfurizer 32 in that order, and releases heat to these reformer 33, air preheater 22, water evaporator 42, and desulfurizer 32 as it passes through.

[0092] Specifically, the exhaust gas discharged from the water evaporator 42 is introduced into the housing 60 via the exhaust gas inlet pipe 81 of the desulfurizer 32. The fuel introduced into the housing 60 then flows through the exhaust gas inlet tank 616, the exhaust gas flow pipe 83, and the exhaust gas outlet tank 611 in that order, and is discharged to the outside of the desulfurizer 32 via the exhaust gas outlet pipe 82. As the exhaust gas flows through the desulfurizer 32 in this manner, it dissipates heat to the desulfurizing agent filled in the upstream filling section 613 and the downstream filling section 615, respectively, via the exhaust gas flow pipe 83. In addition, as the exhaust gas flows through the desulfurizer 32 in this manner, it dissipates heat to the large-diameter baffle plate 91 and the small-diameter baffle plate 92 via the exhaust gas flow pipe 83.

[0093] In this way, the high-temperature exhaust gas generated in the combustor 53 is used as a heat source for the reformer 33, air preheater 22, water evaporator 42, and desulfurizer 32. This allows the reformer 33, air preheater 22, water evaporator 42, and desulfurizer 32 to be heated without the need for additional heating equipment, thereby enabling high efficiency of the fuel cell system 1.

[0094] The exhaust gas that has passed through the reformer 33, air preheater 22, water evaporator 42, and desulfurizer 32 is then discharged to the outside of the system as exhaust gas.

[0095] Incidentally, when the desulfurizing agent in the desulfurizer 32 removes sulfur components from the fuel, the higher the temperature of the desulfurizing agent, the greater the amount of sulfur components that can be removed. For this reason, when heating the desulfurizer 32 with exhaust gas, exhaust gas at a temperature similar to, or higher than, the target heating temperature of the desulfurizing agent is used. For example, if the sulfur components contained in the fuel introduced into the desulfurizer 32 can be stably removed by setting the temperature of the desulfurizing agent to 250°C, exhaust gas at 250°C is introduced into the desulfurizer 32 to heat the desulfurizing agent to 250°C. As a result, the desulfurizer 32 can sufficiently remove the sulfur components contained in the fuel introduced into the desulfurizer 32 with the desulfurizing agent heated to a high temperature.

[0096] However, even when exhaust gas at 250°C is introduced into the desulfurizer 32 to heat it, if the temperature of the fuel supplied to the desulfurizer 32 is lower than the temperature of the desulfurizing agent, the desulfurizing agent may be cooled to a temperature lower than the target temperature due to heat absorption by the fuel.

[0097] In particular, the desulfurizing agent packed near the fuel inlet pipe 71, where fuel is introduced into the desulfurizer 32, cools down more easily than the desulfurizing agent packed near the fuel outlet pipe 72, where fuel is discharged from the desulfurizer 32, because more heat is absorbed by the fuel. Specifically, the desulfurizing agent packed in the upstream packing section 613 cools down more easily than the desulfurizing agent packed in the downstream packing section 615. As a result, a temperature difference occurs between the desulfurizing agent packed in the upstream packing section 613 and the desulfurizing agent packed in the downstream packing section 615 of the desulfurizer 32. In other words, there is a temperature variation in the desulfurizing agent packed in the desulfurizer 32.

[0098] Such temperature drops and temperature fluctuations of the desulfurizing agent reduce the amount of sulfur components that the desulfurizing agent can remove. In other words, temperature drops and temperature fluctuations of the desulfurizing agent reduce the amount of sulfur components that the desulfurizing agent can adsorb, which leads to a deterioration in the desulfurization capacity of the desulfurizer 32.

[0099] In view of this, the desulfurizer 32 of this embodiment has a fuel preheating unit 612 that heats the fuel introduced from the fuel inlet pipe 71. The specific operation of the fuel preheating unit 612 will be explained with reference to Figure 5. The arrows shown in Figure 5 indicate the flow of fuel.

[0100] As shown in Figure 5, the fuel introduced into the housing 60 from the fuel inlet pipe 71 flows into the space between the small-diameter baffle plate 92 and the exhaust gas collection plate 65 at one end of the axial DRa. The fuel that flows into this space between the small-diameter baffle plate 92 and the exhaust gas collection plate 65 flows horizontally along the plate surfaces of the small-diameter baffle plate 92 and the exhaust gas collection plate 65. This horizontally flowing fuel flows into the baffle plate inter-flow channel 93 at one end of the axial DRa via the outer peripheral flow channel 921. The flow direction of the fuel that flows into the baffle plate inter-flow channel 93 at one end of the axial DRa is sequentially changed by a plurality of large-diameter baffle plates 91 and small-diameter baffle plates 92 that are arranged alternately along the axial DRa.

[0101] Specifically, first, the fuel that flows into the baffle plate passage 93 at one end of the axial DRa has its flow direction changed along the shape of the one-sided bend 911, and then flows from the outside to the inside of the radial DRr. That is, the fuel that flows towards the inner circumferential surface 621 in the space between the small-diameter baffle plate 92 and the exhaust gas collection plate 65 has its flow direction changed by approximately 180° by the one-sided bend 911, flows into the baffle plate passage 93, and flows towards the axial center CL.

[0102] Fuel flowing from the inside to the outside of the radial DRr has its flow direction changed along the shape of the other-side bend 922 when it reaches approximately the center of the baffle plate passage 93. As a result, the fuel with the changed flow direction flows through the fuel flow hole 912 into the baffle plate passage 93 immediately to the other side of the axial DRa relative to the baffle plate passage 93 before the flow direction change, and flows from the inside to the outside of the radial DRr. In other words, fuel flowing in the baffle plate passage 93 toward the axis CL has its flow direction changed by approximately 180° by the other-side bend 922, and the baffle plate passage 93 it flows into is changed to the adjacent baffle plate passage 93, and it flows toward the inner circumferential surface 621.

[0103] Then, the fuel flowing through the baffle plate passage 93 from the inside to the outside of the radial DRr flows into the adjacent baffle plate passage 93 immediately on the other side of the axial DRa via the outer peripheral passage 921 and flows from the outside to the inside of the radial DRr. Also, the fuel flowing through the baffle plate passage 93 from the outside to the inside of the radial DRr flows into the adjacent baffle plate passage 93 immediately on the other side of the axial DRa via the fuel flow hole 912 and flows from the inside to the outside of the radial DRr.

[0104] Thus, the fuel flowing into the fuel preheating section 612 meanders through the baffle plate inter-flow channels 93 arranged in the axial direction DRa, flowing from the inside to the outside in the radial direction DRr, and then flowing from the outside to the inside in the radial direction DRr. In addition, the fuel flowing into the fuel preheating section 612 flows along the surface of the large-diameter baffle plate 91 and the small-diameter baffle plate 92 arranged in the axial direction DRa. For this reason, the desulfurizer 32 of this embodiment has a longer flow path for the fuel when it flows through the fuel preheating section 612 compared to a configuration in which the large-diameter baffle plate 91 and the small-diameter baffle plate 92 are not provided in the fuel preheating section 612.

[0105] The fuel that flows into the baffle plate passage 93 at the other end of the axial DRa is discharged from the fuel flow hole 912 of the large-diameter baffle plate 91 toward the space in the fuel preheating section 612 where the large-diameter baffle plate 91 and the small-diameter baffle plate 92 are not provided. The fuel discharged toward the space in the fuel preheating section 612 where the large-diameter baffle plate 91 and the small-diameter baffle plate 92 are not provided then flows into the upstream filling section 613 through the punching holes 661 formed in the upstream desulfurizer support plate 66.

[0106] In this embodiment, the fuel flow holes 912 formed in the large-diameter baffle plate 91 located at the other end of the axial DRa have a larger diameter than the fuel flow holes 912 formed in the other large-diameter baffle plates 91. This makes it less likely for the fuel discharged through the fuel flow holes 912 into the space in the fuel preheating section 612 where the large-diameter baffle plates 91 and small-diameter baffle plates 92 are not provided to become a jet. As a result, when the fuel flows into the upstream filling section 613 through the punching holes 661 formed in the upstream desulfurizer support plate 66, it is easier for the fuel to flow throughout the entire upstream filling section 613.

[0107] In this embodiment, the large-diameter baffle plate 91 and the small-diameter baffle plate 92 are connected to the exhaust gas flow pipe 83. As the exhaust gas flows through the exhaust gas flow pipe 83, they are heated by absorbing heat from the exhaust gas. Therefore, the fuel flowing meanderingly through the baffle plate inter-flow channels 93, which are arranged in multiple axial directions DRa, is heated by absorbing heat from the large-diameter baffle plate 91 and the small-diameter baffle plate 92. In other words, the fuel that flows into the fuel preheating section 612 is heated to a temperature higher than its temperature before flowing into the fuel preheating section 612, using the exhaust gas flowing through the exhaust gas flow pipe 83 as a heat source.

[0108] The fuel that flows into the upstream filling section 613 has its sulfur components removed by the desulfurizing agent filled in the upstream filling section 613, and then flows into the fuel straightening section 614 through the punched holes 671 formed in the filling section partition plate 67.

[0109] Here, the punching holes 671 formed in the filling section partition plate 67 are located around the center of the filling section partition plate 67, and are not formed around the outer edge of the filling section partition plate 67. Therefore, of the fuel flowing through the upstream filling section 613, the fuel flowing around the inner circumferential surface 621 is suppressed by the filling section partition plate 67. When this fuel flowing around the inner circumferential surface 621 flows into the fuel straightening section 614, it is concentrated around the axis CL and flows into the fuel straightening section 614 through the punching holes 671 formed around the center of the filling section partition plate 67. In this embodiment, the filling section partition plate 67 corresponds to a flow suppression section that suppresses the flow of fuel along the surface between the upstream filling section 613 and the downstream filling section 615 on the outer periphery 62.

[0110] Furthermore, the area in the filling section partition plate 67 where the punching holes 671 are formed is covered by the rectifier plate 6141 in the axial direction DRa. As a result, fuel flowing into the fuel rectifier section 614 through the punching holes 671 formed around the center of the filling section partition plate 67 collides with the rectifier plate 6141 and flows to spread throughout the entire fuel rectifier section 614. Consequently, the fuel that has passed through the upstream filling section 613 is agitated by the fuel rectifier section 614 before flowing into the downstream filling section 615. The fuel that has flowed to spread throughout the entire fuel rectifier section 614 then passes through the rectifier section flow path 6142 and the punching holes 681 of the downstream desulfurizer support plate 68 and flows into the downstream filling section 615.

[0111] The reason for stirring the fuel and allowing it to flow into the downstream filling section 615 is explained below. In this embodiment, particulate desulfurizing agent is used in the desulfurizer 32. Therefore, the filling rate of the particulate desulfurizing agent filling the upstream filling section 613 and the downstream filling section 615 is lower around the inner circumferential surface 621 compared to around the axis CL in the upstream filling section 613 and the downstream filling section 615. In other words, the density of the filling agent filling the upstream filling section 613 and the downstream filling section 615 is lower around the inner circumferential surface 621 compared to around the axis CL.

[0112] Therefore, when fuel flows into the upstream filling section 613 and the downstream filling section 615, it tends to flow more easily towards the inner circumferential surface 621, where the density of the desulfurizing agent is lower compared to the area around the axis CL, as it flows through the interior of the upstream filling section 613 and the downstream filling section 615. As a result, the flow rate of fuel flowing through the interior of the upstream filling section 613 and the downstream filling section 615 is higher along the inner circumferential surface 621 compared to the area around the axis CL.

[0113] Therefore, due to the difference in density when the desulfurizing agent is filled into the upstream and downstream filling sections 613 and 615 through which the fuel flows, an uneven distribution of fuel flows between the area around the axis CL and the area around the inner circumferential surface 621. When an uneven distribution of fuel flows into the upstream and downstream filling sections 613 and 615, which are filled with desulfurizing agent, the amount of sulfur components adsorbed by the desulfurizing agent increases in areas where more fuel flows. Consequently, the desulfurizing agent placed in areas with a high fuel flow will have a shorter lifespan compared to the desulfurizing agent placed in areas with a low fuel flow. This is a factor that shortens the lifespan of the desulfurizer 32.

[0114] In contrast, by providing a filling section partition plate 67 with punched holes 671 formed only around the center between the upstream filling section 613 and the downstream filling section 615, the fuel flowing around the inner surface 621 of the upstream filling section 613 can be guided to the area around the axis CL. Then, the fuel that has passed through the upstream filling section 613 and flowed into the fuel straightening section 614 can be stirred by the straightening plate 6141 to spread throughout the entire fuel straightening section 614 before it flows into the downstream filling section 615.

[0115] Therefore, when introducing fuel into the downstream filling section 615, the fuel is introduced through the punching holes 681 formed over almost the entire area of ​​the downstream desulfurizer support plate 68, allowing it to flow throughout the entire downstream filling section 615. As a result, fuel flowing around the inner circumferential surface 621 in the upstream filling section 613 is less likely to flow around the inner circumferential surface 621 in the downstream filling section 615, thus preventing a shortened lifespan for the desulfurizer 32.

[0116] As described above, the desulfurizer 32 of this embodiment has a fuel preheating section 612 located upstream of the position where the upstream filling section 613 and the downstream filling section 615 are provided inside the housing 60, which houses a large-diameter baffle plate 91 and a small-diameter baffle plate 92 that transfer heat from the exhaust gas to the fuel.

[0117] According to this, even if the fuel flowing into the desulfurizer 32 is at a lower temperature than the desulfurizing agent, the heat from the exhaust gas can be used to heat the fuel before it flows into the upstream filling section 613 and the downstream filling section 615. Therefore, when the fuel flows into the upstream filling section 613 and the downstream filling section 615, it is possible to suppress the decrease in the temperature of the desulfurizing agent filled in the upstream filling section 613 and the downstream filling section 615 due to this fuel. In addition, it becomes less likely for a temperature difference to occur between the desulfurizing agent filled in the upstream filling section 613 and the desulfurizing agent filled in the downstream filling section 615. Consequently, it is possible to avoid a decrease in the amount of sulfur components that the desulfurizing agent can adsorb due to the inflow of low-temperature fuel, and the desulfurization capacity of the desulfurizer 32 can be improved. Furthermore, by providing the fuel preheating section 612 inside the housing 60, the fuel preheating section 612 can be integrated with the housing 60, thus enabling the desulfurizer 32 to be miniaturized.

[0118] Here, if the fuel flowing into the desulfurizer 32 is at a lower temperature than the desulfurizing agent, the desulfurizing agent packed closer to the fuel inlet pipe 71 will absorb more heat from the fuel compared to the desulfurizing agent packed closer to the fuel outlet pipe 72, causing its temperature to drop more easily. For this reason, the desulfurizing agent packed in the upstream packing section 613 will have a lower desulfurizing capacity compared to the desulfurizing agent packed in the downstream packing section 615.

[0119] Therefore, if the desulfurizer 32 of this embodiment does not have a fuel preheating section 612, measures such as filling the upstream filling section 613, which is prone to a decrease in desulfurization capacity, with a larger amount of desulfurizing agent than necessary, taking into account the decrease in desulfurization capacity, would be necessary. However, according to this embodiment, it becomes unnecessary to fill the upstream filling section 613 with such excess desulfurizing agent. Therefore, the amount of desulfurizing agent to be filled into the upstream filling section 613 can be optimized, and the manufacturing cost of the desulfurizer 32 can be reduced.

[0120] Furthermore, immediately after starting the fuel cell system 1, the desulfurizing agent packed in the upstream filling section 613 and the downstream filling section 615 is not heated by the exhaust gas generated in the combustor 53. Also, heating the desulfurizing agent packed in the upstream filling section 613 and the downstream filling section 615 to the target heating temperature of the desulfurizing agent using only the heat of the exhaust gas flowing through the exhaust gas passage 54 tends to require a long heating time.

[0121] In contrast, the desulfurizer 32 of this embodiment allows the desulfurizing agent filled in the upstream and downstream filling sections 613 and 615 to be heated by the heated fuel, which is heated using the heat of the exhaust gas. Therefore, the time required to heat the desulfurizing agent to the target heating temperature can be shortened.

[0122] Furthermore, according to the above embodiment, the following effects can be obtained.

[0123] (1) In the above embodiment, the large-diameter baffle plate 91 and the small-diameter baffle plate 92 form a baffle plate inter-flow channel 93 through which fuel flows in the fuel preheating section 612, and also change the direction of fuel flow when it flows into the fuel preheating section 612.

[0124] According to this, compared to a configuration in which the fuel preheating section 612 is not provided with a large-diameter baffle plate 91 and a small-diameter baffle plate 92, the flow path of the fuel flowing into the fuel preheating section 612 becomes longer. Therefore, when the fuel flows through the fuel preheating section 612 and heat from the exhaust gas is transferred to the fuel, the amount of heat transferred from the exhaust gas to the fuel can be increased. Consequently, the desulfurization capacity of the desulfurizer 32 can be further improved.

[0125] (2) In the above embodiment, the large-diameter baffle plate 91 is connected to the exhaust gas flow pipe 83 through which it passes, and is formed in the shape of a plate with a plate surface that is perpendicular to the direction of fuel flow when it flows into the fuel preheating section 612. The large-diameter baffle plate 91 has fuel flow holes 912 through which fuel flows.

[0126] According to this, the large-diameter baffle plate 91 having fuel flow holes 912 can easily lengthen the flow path for fuel that flows into the fuel preheating section 612. In addition, the large-diameter baffle plate 91 can be heated by transferring the heat of the exhaust gas to the large-diameter baffle plate 91 via the exhaust gas flow pipe 83. Therefore, as the fuel flows along the surface of the large-diameter baffle plate 91, the fuel can be heated via the large-diameter baffle plate 91, making it easier to transfer the heat of the exhaust gas to the fuel compared to when the large-diameter baffle plate 91 is not connected to the exhaust gas flow pipe 83.

[0127] (3) In the above embodiment, the housing 60 is cylindrical with an axis CL and has an outer peripheral portion 62 surrounding the axis CL. The large-diameter baffle plate 91 abuts against the inner peripheral surface 621 of the outer peripheral portion 62 and has fuel flow holes 912 through which fuel flows. The small-diameter baffle plate 92 is formed with a smaller outer diameter than the large-diameter baffle plate 91 and forms an outer peripheral flow path 921 through which fuel flows between the inner peripheral surface 621 of the outer peripheral portion 62 and the outer edge of the small-diameter baffle plate 92. The large-diameter baffle plate 91 and the small-diameter baffle plate 92 are arranged alternately along the direction in which the axis CL extends.

[0128] According to this, the fuel flowing into the fuel preheating section 612 flows through the baffle plate inter-flow channel 93 between the large-diameter baffle plate 91 and the small-diameter baffle plate 92, and also flows through the outer peripheral flow channel 921 formed by the fuel flow holes 912 of the large-diameter baffle plate 91 and the small-diameter baffle plate 92. The fuel flowing into the fuel preheating section 612 can be made to flow in a meandering manner along the plate surfaces of the large-diameter baffle plate 91 and the small-diameter baffle plate 92. As a result, the flow path through which the fuel flowing into the fuel preheating section 612 flows can be lengthened, and the contact area between the fuel and the large-diameter baffle plate 91 and the contact area between the fuel and the small-diameter baffle plate 92 can be increased, making it easier to transfer heat from the exhaust gas to the fuel.

[0129] (4) In the above embodiment, multiple exhaust gas flow pipes 83 are provided inside the housing 60.

[0130] According to this, compared to a configuration in which only one exhaust gas flow pipe 83 is provided within the housing 60, the amount of heat from the exhaust gas transmitted to the fuel and desulfurizer via the exhaust gas flow pipe 83 can be increased.

[0131] (5) In the above embodiment, the desulfurizer 32 is applied to a fuel cell system 1 comprising a fuel cell 10 and a combustor 53 that burns fuel off-gas and off-gas air discharged from the fuel cell 10 to generate high-temperature exhaust gas. The exhaust gas generated by the combustor 53 is then used to heat the desulfurizer and fuel through heat exchange.

[0132] According to this, the high-temperature exhaust gas generated in the combustor 53 can be used as a heat source for the desulfurizer 32. This makes it possible to heat the desulfurizing agent without using equipment to heat the desulfurizer 32, thereby achieving high efficiency in the fuel cell system 1.

[0133] (6) In the above embodiment, the housing 60 has an upstream filling section 613 and a downstream filling section 615 located downstream of the upstream filling section 613 in the direction of fuel flow through the inside of the housing 60. The housing 60 also has an outer periphery 62 surrounding the upstream filling section 613 and the downstream filling section 615, and a filling section partition plate 67 that suppresses the flow of fuel along the surface between the upstream filling section 613 and the downstream filling section 615 on the outer periphery 62.

[0134] According to this, fuel flowing around the inner surface 621 of the outer periphery 62 in the upstream filling section 613 is less likely to flow around the inner surface 621 of the outer periphery 62 in the downstream filling section 615. Therefore, it is possible to suppress the shortening of the lifespan of the desulfurizer 32 caused by the density of the packing material.

[0135] (7) In the above embodiment, the housing 60 has an exhaust gas inlet 641 for introducing exhaust gas into the housing 60 and an exhaust gas outlet 631 for guiding the exhaust gas introduced into the housing 60 to the outside of the housing 60. The exhaust gas outlet 631 has a larger opening area compared to the exhaust gas inlet 641.

[0136] According to this, the pressure loss when exhaust gas is discharged to the outside of the housing 60 can be reduced compared to the case where the opening area of ​​the exhaust gas outlet 631 is formed to be smaller than that of the exhaust gas inlet 641.

[0137] (Second Embodiment) Next, the second embodiment will be described with reference to Figures 6 and 7. In this embodiment, the shape of the outer periphery 62 differs from that of the first embodiment. Otherwise, it is the same as the first embodiment. For this reason, in this embodiment, the parts that differ from the first embodiment will be mainly described, and the parts that are the same as the first embodiment may be omitted from the description.

[0138] As shown in Figures 6 and 7, the outer periphery 62 of this embodiment is configured in a wave shape extending in the axial direction DRa. Specifically, the outer periphery 62 is formed with protrusions 62a projecting from the inside outward in the radial direction DRr and recesses 62b recessing from the outside inward in the radial direction DRr, arranged alternately in the axial direction DRa.

[0139] As shown in Figure 7, the protrusions 62a and recesses 62b are formed with a roughly triangular cross-section in a plane parallel to the axial direction DRa. The distance between adjacent protrusions 62a via the recesses 62b is compared to the size of the particulate desulfurizing agent D. Large It is formed. Furthermore, the distance between adjacent recesses 62b via the protrusion 62a is the same as the distance between adjacent protrusions 62a via the recess 62b, and compared to the size of the particulate desulfurizing agent D Large It is formed. Hereinafter, the distance between adjacent protrusions 62a via the recess 62b and the distance between adjacent recesses 62b via the protrusion 62a will also be referred to as the outer circumference pitch P.

[0140] Thus, the outer edge pitch P is compared to the size of the particulate desulfurizing agent D. LargeAs a result of this formation, it becomes easier to fill the upstream filling section 613 and the downstream filling section 615 with the desulfurizing agent D along the shape of the outer circumference 62. Therefore, when filling the upstream filling section 613 and the downstream filling section 615 with the desulfurizing agent D, it becomes less likely that a difference in density will occur between the filling material around the axis CL and the filling material around the inner circumferential surface 621. In addition, when fuel flows through the inside of the upstream filling section 613 and the downstream filling section 615, the flow path of the fuel flowing along the inner circumferential surface 621 becomes longer compared to the fuel flowing around the axis CL.

[0141] According to this, when the fuel flowing into the upstream filling section 613 and the downstream filling section 615 flows through the interior of the upstream filling section 613 and the downstream filling section 615, it becomes less likely for the amount of fuel flowing to be uneven between the area around the axis CL and the area around the inner circumferential surface 621. Therefore, it is possible to suppress the shortening of the lifespan of the desulfurizer 32 caused by the density of the packing material being filled.

[0142] The shape of the protrusion 62a and the recess 62b is not limited, and the cross-section in the direction perpendicular to the axial direction DRa may be semicircular, rectangular, or the like.

[0143] Furthermore, the filling rate of the desulfurizing agent in the upstream filling section 613 and the downstream filling section 615 tends to be lower compared to the filling rate of the desulfurizing agent in other parts of the exhaust gas flow pipe 83. In other words, the density of the filler in the upstream filling section 613 and the downstream filling section 615 is lower around the outer surface of the exhaust gas flow pipe 83 compared to the density in other parts.

[0144] Therefore, although not shown in the figures, the piping shape of the exhaust gas flow pipe 83 may be the same as the shape of the outer circumference 62 in this embodiment. That is, the piping shape of the exhaust gas flow pipe 83 may be formed as a wave shape extending in the axial direction DRa.

[0145] (Other embodiments) While representative embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above and can be modified in various ways, for example, as follows.

[0146] In the above-described embodiment, an example was described in which a baffle plate 90 is provided inside the housing 60 of the desulfurizer 32, but it is not limited to this. For example, the desulfurizer 32 may be configured without a baffle plate 90 inside the housing 60. In this case, the heat of the exhaust gas is transferred to the fuel that flows into the fuel preheating section 612 via the exhaust gas flow pipe 83 and the air in the fuel preheating section 612. Therefore, the air in the fuel preheating section 612 functions as a heat transfer section that transfers the heat of the exhaust gas from the exhaust gas guided into the housing 60 by the exhaust gas flow pipe 83 to the fuel.

[0147] In the above-described embodiment, an example was explained in which the heat transfer section is composed of a plate-shaped baffle plate 90 having a plate surface oriented perpendicular to the direction of fuel flow when it flows into the fuel preheating section 612. However, the shape of the heat transfer section is not limited to this. For example, the heat transfer section may be composed of a plate-shaped baffle plate 90 having a plate surface oriented in a direction different from the perpendicular direction, as long as it intersects with the direction of fuel flow when it flows into the fuel preheating section 612. Alternatively, the heat transfer section may be formed from a helically shaped plate material.

[0148] In the above-described embodiment, an example was given in which a large-diameter baffle plate 91 and a small-diameter baffle plate 92 are provided inside the housing 60, but the desulfurizer 32 is not limited to this. The desulfurizer 32 may be configured in which only one of the large-diameter baffle plate 91 and the small-diameter baffle plate 92 is provided inside the housing 60. In addition, the desulfurizer 32 may be configured in which fins are provided to promote heat transfer from exhaust gas to fuel, in addition to the large-diameter baffle plate 91 and the small-diameter baffle plate 92.

[0149] In the above-described embodiment, an example was given in which multiple exhaust gas flow pipes 83 are provided inside the housing 60, but the invention is not limited to this. For example, the desulfurizer 32 may be configured in which only one exhaust gas flow pipe 83 is provided inside the housing 60.

[0150] In the embodiments described above, an example was given in which the desulfurizer 32 is applied to a fuel cell system 1 comprising a fuel cell 10 and a combustor 53 that burns fuel off-gas and off-gas air discharged from the fuel cell 10 to generate high-temperature exhaust gas. An example was described in which the desulfurizing agent in the desulfurizer 32 is heated by the exhaust gas generated in the combustor 53, but the invention is not limited to this. For example, the desulfurizer 32 may be applied to a system other than the fuel cell system 1. Furthermore, the desulfurizer 32 may be configured in which the desulfurizing agent and fuel are heated by a fluid other than the exhaust gas.

[0151] In the above-described embodiment, an example was described in which the desulfurizer 32 has a filling section partition plate 67 that suppresses the flow of fuel along the surface between the upstream filling section 613 and the downstream filling section 615 on the outer periphery 62, but it is not limited to this. For example, the desulfurizer 32 may have a configuration in which the filling section partition plate 67 is not located inside the housing 60, and a fuel preheating section 612 may not be formed.

[0152] In the above-described embodiment, an example was given in which the exhaust gas outlet 631 has a larger opening area compared to the exhaust gas inlet 641, but the invention is not limited to this. For example, the opening area of ​​the exhaust gas outlet 631 may be less than or equal to the opening area of ​​the exhaust gas inlet 641.

[0153] In the embodiments described above, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where they are explicitly stated to be essential or where they are clearly considered essential in principle.

[0154] In the embodiments described above, if numerical values ​​such as the number, numerical values, quantities, or ranges of the components of the embodiment are mentioned, the embodiment is not limited to those specific numbers unless explicitly stated as particularly essential or clearly limited to a specific number in principle.

[0155] In the embodiments described above, when referring to the shape, positional relationships, etc. of the components, the definition is not limited to those shapes, positional relationships, etc., unless otherwise specifically stated or when the definition is fundamentally limited to a particular shape, positional relationship, etc. [Explanation of Symbols]

[0156] 60 cabinets 83 Heating channel section 90 Heat transfer section 612 Fuel preheating section 613, 615 Desulfurizing agent filling section

Claims

1. A desulfurizer for removing sulfur components contained in reforming raw materials, A housing (60) through which the reforming raw material flows and which is filled with a desulfurizing agent filling section (613, 615) that removes the sulfur component of the reforming raw material, The housing includes a heating channel section (83) that guides a heating fluid into the housing to heat the desulfurizing agent by exchanging heat with the desulfurizing agent, The housing has a fuel preheating section (612) upstream of the position where the desulfurizing agent filling section is provided in the flow direction of the reforming raw material flowing inside the housing, which houses heat transfer sections (90, 91, 92) that transfer heat from the heating fluid introduced into the housing by the heating channel section to the reforming raw material. The heat transfer section includes a plate-shaped plate portion (91) through which the heating channel portion is connected and which has a plate surface in a direction intersecting the flow direction of the reforming raw material when it flows into the fuel preheating section, and a fuel preheating channel forming section (90, 91, 92) which forms a channel through which the reforming raw material flows in the fuel preheating section, thereby increasing the amount of heat transferred from the fuel preheating channel forming section to the reforming raw material by changing the flow direction of the reforming raw material when it flows into the fuel preheating section. A desulfurizer, wherein the plate portion has fuel flow holes (912) through which the reforming raw material flows.

2. The housing is cylindrical with an axis (CL) and has an outer circumference (62) surrounding the axis. The plate portion includes a disc-shaped first plate portion (91) that abuts against the inner surface of the outer periphery and has the fuel flow holes, and a second plate portion (92) which is formed with a smaller outer diameter than the first plate portion and forms an outer periphery flow path (921) through which the reforming material flows between itself and the inner surface of the outer periphery. The desulfurizer according to claim 1, wherein the first plate portion and the second plate portion are arranged alternately along the direction in which the axis extends.

3. The desulfurizer according to claim 1, wherein the heating channel section is provided in multiple locations within the housing.

4. The desulfurizer is applied to a fuel cell system comprising a fuel cell (10) that outputs electrical energy through an electrochemical reaction between a fuel gas and an oxidizer gas, and a combustor (53) that burns the fuel off-gas and off-gas air discharged from the fuel cell to generate high-temperature exhaust gas. The desulfurizer according to claim 1, wherein the heated fluid is the exhaust gas generated in the combustor.

5. The desulfurizing agent filling section has an upstream filling section (613) and a downstream filling section (615) located downstream of the upstream filling section in the flow direction of the reforming raw material flowing inside the housing, The desulfurizer according to claim 1, wherein the housing has an outer periphery (62) surrounding the upstream filling section and the downstream filling section, and a flow suppression section (67) that suppresses the flow of the reforming material flowing along the surface between the upstream filling section and the downstream filling section on the outer periphery.

6. The housing has a heating fluid inlet (641) for introducing the heating fluid into the inside of the housing and a heating fluid outlet (631) for guiding the heating fluid introduced into the inside of the housing to the outside. The desulfurizer according to claim 1, wherein the heating fluid outlet has a larger opening area than the heating fluid inlet.

7. The housing is cylindrical with an axis (CL) and has an outer circumference (62) surrounding the axis. The desulfurizer according to claim 1, wherein the outer periphery is formed in a wave shape extending along the direction in which the axis extends.

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