JP2011136869A - Apparatus for producing reformed gas, operation control method thereof, and fuel cell system - Google Patents

Abstract

A reforming unit operation control method capable of suppressing a catalyst deterioration with a simple configuration and performing a stable treatment for a long period of time is provided.
Inside a CO converter 810, a gas diffusion region 812 into which reformed gas flows and a CO conversion reaction region 813 filled with a CO conversion catalyst are provided in communication with each other. In the CO selective oxidizer 830, a diffusion region 832 into which the reformed gas after CO conversion flows and a CO selective oxidation reaction region filled with a CO selective oxidation catalyst are provided in communication with each other. Supplying water for generating steam for steam reforming treatment in the reformer 620 before the reforming catalyst reaches 400 ° C. when the temperature of the reformer 620 rises, purging the remaining hydrocarbon fuel with steam, Can prevent coking. Even if the CO converter 810 and the CO selective oxidizer 830 are not heated by an electric heater, the water in which the water vapor is condensed is stored in the gas diffusion region 812 and the diffusion region, and the catalyst can be prevented from getting wet and deteriorating.
[Selection] Figure 2

Description

The present invention relates to a reforming method in which a raw material gas containing hydrocarbon fuel and mixed with water vapor is brought into contact with a reforming catalyst heated by a heating means to produce a reformed gas mainly composed of hydrogen gas (H ₂ ). The present invention relates to a gas manufacturing apparatus, an operation control method thereof, and a fuel cell system including the reformed gas manufacturing apparatus.

Conventionally, in a reformer for producing a reformed gas mainly composed of hydrogen gas (H ₂ ) by bringing a raw material gas containing hydrocarbon fuel and mixed with water vapor into contact with a reforming catalyst heated by a heating means. Various driving methods are known. (For example, see Patent Documents 1 to 4).
Patent Document 1 discloses a fuel cell power generation system that purges the interior of a reformer with a city gas used as a reforming material as a purge gas when the system including the reformer and the fuel cell is stopped. Configuration is adopted.
Patent Document 2 discloses that when the temperature of the reforming catalyst layer filled with the reforming catalyst of the reformer is lowered, the reformed gas in the reformer is purged with steam, and then the temperature of the reforming catalyst layer is increased. However, before the temperature at which the raw material gas does not thermally decompose and below the temperature at which the water vapor condenses, the raw material gas is introduced and the water vapor in the reformer is purged.
The one described in Patent Document 3 is a reforming unit including a reformer, a CO converter that converts CO in the reformed gas, and a CO selective oxidizer that oxidizes CO in the reformed gas into carbon dioxide. When the operation is stopped, the reformed gas stored in the storage tank is purged when the pressure in the reformer becomes equal to or lower than the atmospheric pressure.
In Patent Document 4, the raw material gas is reformed in the reforming reactor, and then the fuel gas obtained by removing CO mixed in the shift reactor and the CO removal reactor is modified when the operation is stopped. A structure is employed in which the catalyst is prevented from being oxidized by purging the quality reactor, the shift reactor, and the CO removal reactor.

JP 2003-229156 A JP 2002-151124 A JP 2009-76327 A JP 2004-134226 A

However, when the operation is stopped, in the configuration in which the material gas is finally purged as described in Patent Document 1 and Patent Document 2 described above, the material gas is filled when the engine is restarted. If heating is performed in the state of remaining, the catalyst may be deteriorated by coking. For this reason, once the raw material gas is purged with water vapor, it is possible to react by supplying the raw material gas again after heating it to the temperature required for the reforming process. Since the temperature is not so high at the beginning of the time, there is a possibility that water vapor is condensed and the catalyst gets wet and deteriorates in a CO converter or CO selective oxidizer whose temperature rise is relatively slow.
On the other hand, when the operation is stopped, the configuration of purging with the reformed gas as described in Patent Document 3 and Patent Document 4 described above requires the provision of a tank for storing the reformed gas, which increases the size and structure of the apparatus. May cause inconvenience such as.

  In view of the above, an object of the present invention is to provide a reformed gas production apparatus, a method for controlling the operation thereof, and a fuel cell system that can perform stable treatment for a long time by suppressing catalyst deterioration with a simple configuration. There is.

The method for controlling the operation of the reformed gas production apparatus according to the present invention is a modification in which a raw material gas containing a hydrocarbon fuel and steam is brought into contact with a reforming catalyst in a heated atmosphere to perform steam reforming treatment and mainly contain hydrogen gas. A reformer for generating a gas, and the reformed gas generated by the reformer is supplied to convert carbon monoxide (CO) in the reformed gas into carbon dioxide (CO ₂ ) by a CO shift catalyst. A CO converter and a CO selective oxidizer that is supplied with the reformed gas treated in the CO converter and oxidizes CO remaining in the reformed gas to CO ₂ by a CO selective oxidation catalyst or CO is methanated An operation control method for a reformed gas production apparatus comprising a methanation device, wherein the CO converter is an inflow chamber into which the reformed gas flows, and the inflow chamber is filled with a catalyst. Catalyst packing And the steam that can purge the gaseous hydrocarbon fuel filled in the reformer when the reforming catalyst reaches a predetermined temperature when the temperature of the reformer rises. Water is supplied, and the water supply is stopped before the water vapor flowing into the inflow chamber condenses and overflows and flows into the catalyst filling chamber.

  In the present invention, when the generation of the reformed gas is interrupted, the reformer, the CO converter, and the water vapor are generated by stopping the supply of the hydrocarbon fuel and supplying only the water. After purging the inside of the CO selective oxidizer or the methanation device, the steam condenses and the inside of the reformer, the CO converter, and the CO selective oxidizer or the methanation device is reduced from the atmospheric pressure to a negative pressure. In such a case, it is preferable to supply the gaseous hydrocarbon fuel.

The reformed gas production apparatus according to the present invention generates a reformed gas mainly composed of hydrogen gas by bringing a raw material gas containing hydrocarbon fuel and steam into contact with a reforming catalyst in a heated atmosphere to perform steam reforming treatment. And a CO converter that is supplied with the reformed gas generated by the reformer and converts carbon monoxide (CO) in the reformed gas into carbon dioxide (CO ₂ ) by a CO shift catalyst. a methanation unit to the CO transformer in and processed said reformed gas is supplied the reforming of CO selective oxidizer or CO and CO remaining in the gas is oxidized to CO ₂ by the CO selective oxidation catalyst is a methanation And a control device, wherein the CO converter includes an inflow chamber into which the reformed gas flows and a catalyst filling chamber in which the catalyst is connected to the inflow chamber. And the system The apparatus supplies water for generating the water vapor that can purge the gaseous hydrocarbon fuel filled in the reformer when the reforming catalyst reaches a predetermined temperature when the temperature of the reformer rises. And the control is performed to stop the supply of water before the water vapor flowing into the inflow chamber condenses and overflows and flows into the catalyst filling chamber.

In the present invention, the inflow chamber and the catalyst filling chamber are defined by a partition plate having a plurality of holes through which the reformed gas can flow, and are vertically above the inflow chamber. It is preferable that the catalyst filling chamber is provided in a state where it is located.
Further, the reformer includes a combustor that heats the reforming catalyst by burning at least one of the hydrocarbon fuel, the raw material gas, or the reformed gas, the CO converter, and The CO selective oxidizer or the methanation device is stacked in a radial direction, and is formed in a multilayer structure in which the combustion gas of the combustor flows between the CO converter and the CO selective oxidizer or the methanation device. It is preferable to have a configuration as described above.
In addition, a CO selective oxidizer or methanation device may be used that includes an inflow chamber into which the reformed gas flows and a catalyst filling chamber that is connected to the inflow chamber and is filled with a catalyst. .

  A fuel cell system according to the present invention includes a reformed gas production apparatus according to the present invention, an oxygen-containing gas supply means for supplying an oxygen-containing gas, the reformed gas generated by the reformed gas production apparatus, and And a fuel cell that generates electric power using the oxygen-containing gas supplied by the oxygen-containing gas supply means.

  According to the present invention, the CO converter is provided with an inflow chamber into which the reformed gas flows and a catalyst filling chamber that is communicated with the inflow chamber and is filled with a catalyst. When the reforming catalyst reaches a predetermined temperature when the temperature rises, water is supplied to generate water vapor that can purge the gaseous hydrocarbon fuel filled in the reformer, and the water vapor flowing into the inflow chamber is condensed. Since the supply of water is stopped before it overflows and flows into the catalyst filling chamber, even if hydrocarbon fuel remains in the reformer, steam is generated by the supplied water and purged. Deterioration due to coking can be prevented, and even if the CO converter is not sufficiently heated and water vapor is condensed, it will flow into the inflow chamber once and become dewed. Therefore, the catalyst becomes wet and deteriorates in the CO converter. Can be prevented for a long time It can provide the processing.

1 is a block diagram showing a schematic configuration of a fuel cell system according to the present invention. It is side surface sectional drawing which shows schematic structure of the reforming unit in the said fuel cell system. It is side surface sectional drawing which shows schematic structure of the combustion chamber part of the said modification | reformation unit. It is side surface sectional drawing which shows schematic structure of the modification part of the said modification unit. It is the expanded side sectional view which shows a part of reformer of the said reforming unit. It is the expanded side sectional drawing which shows a part of gas heat exchange part of the said modification | reformation unit. It is a top view which shows the protection tube attachment piece part attached to the 1st reformer member of the said modification | reformation container. It is a top view which shows the assembly | attachment state of the 1st cylindrical member and the 2nd cylindrical member of the said gas heat exchange part. It is a top view which shows the boiler of the said modification | reformation unit. It is the side view which notched a part which shows the boiler of the said modification | reformation unit. It is a top view which shows the CO removal part of the said modification | reformation unit. It is a bottom view which shows the said CO removal part. It is side surface sectional drawing which shows the CO removal part of the said modification | reformation unit. It is the expanded side sectional view which shows a part of said CO removal part. It is the expanded side sectional view which shows the connection part of CO converter and CO selective oxidizer. It is side surface sectional drawing which shows the exhaust gas cooler of the said CO removal part. It is a bottom view which shows the exhaust gas cooler of the said CO removal part.

[Configuration of fuel cell system]
Hereinafter, an embodiment according to the fuel cell system of the present invention will be described.
In the present embodiment, the configuration of the fuel cell system including the reforming unit of the present invention is illustrated. However, the configuration is not limited to the configuration used for the fuel cell system, and for example, as a hydrogen gas production apparatus, the reforming unit alone is used. It may be configured. In addition, the configuration using gaseous hydrocarbon fuel such as liquefied petroleum gas or city gas as the raw fuel mixed with water vapor is exemplified, but not limited thereto, for example, liquid fuel such as kerosene is mixed with water vapor. However, the present invention can also be applied to configurations using various hydrocarbon fuels, such as a configuration for preparing raw material gas. Furthermore, although the system configuration for homes is exemplified, the present invention can be applied to a relatively large system configuration used for, for example, an apartment house or various stores.
FIG. 1 is a block diagram showing a schematic configuration of a fuel cell system in the present embodiment. FIG. 1 shows the configuration of the reforming unit in separate blocks for convenience of explanation.

(overall structure)
In FIG. 1, reference numeral 100 denotes a fuel cell system. The fuel cell system 100 uses a raw fuel containing a hydrocarbon fuel as a raw material and steam reforms the reformed gas containing hydrogen as a main component to remove mixed CO. The fuel cell stack 200 generates power using fuel gas.
Here, as the raw fuel, for example, natural gas mainly composed of methanol, dimethyl ether, methane, city gas mainly composed of this natural gas, synthetic fuel derived from natural gas, etc., and liquefied petroleum gas (LPG) ), Petroleum hydrocarbons such as naphtha and kerosene can be used.

The fuel cell system 100 includes a raw fuel supply means 110 that constitutes a distribution path that is a pipe for supplying raw fuel. This raw fuel supply means can be applied to any structure that supplies raw fuel including hydrocarbon fuel, such as a structure in which raw fuel is supplied from a raw fuel storage means 10 such as a cylinder or a tank to be installed.
The raw fuel supply means 110 is connected to a desulfurization device 300.

The desulfurization apparatus 300 removes the sulfur content in the raw fuel supplied from the raw fuel supply means 110 to 0.01 ppm or less, for example.
The desulfurization apparatus 300 includes a deoxygenation means (not shown), a desulfurizer 310, and the like. As the desulfurization device 300, when a liquid material such as kerosene is used as the raw fuel, a gas-liquid separation device for separating the gas phase component is provided downstream of the desulfurizer 310 to prevent pulsating flow. May be.

The deoxygenation means removes oxygen mixed in the raw fuel flow path from the raw fuel supply means 110 to the desulfurizer 310.
The deoxygenating means includes a deoxygenation container filled with a deoxidizing agent. Examples of the oxygen scavenger include oxygen adsorbents that adsorb oxygen such as iron powder granules, polyhydric alcohol compounds, phenol compounds, unsaturated fats and oils, copper powder granules, and nickel powder granules.

The desulfurizer 310 is connected to a deoxygenation means, and desulfurizes the raw fuel from which the mixed oxygen is removed. The desulfurizer 310 includes a desulfurization container (not shown) filled with a desulfurizing agent.
As the desulfurizing agent, for example, a stabilized desulfurizing agent containing at least one metal selected from iron, nickel, copper, cobalt and manganese, particularly nickel is preferable. In the case where a liquid fuel such as kerosene is used as the raw fuel, the desulfurizer 310 may be provided with heating means such as an electric heater in the desulfurization vessel in order to efficiently perform the desulfurization process.

A reforming unit 400 is connected to the desulfurizer 310 of the desulfurization apparatus 300.
As will be described in detail later, the reforming unit 400 steam-reforms the raw material gas into a fuel gas as a hydrogen-rich reformed gas.
The reforming unit 400 includes a steam mixer 140, a heat exchange device 160, a reformer 620, a CO converter 810, and a CO selective oxidizer 830.

The steam mixer 140 mixes steam with the raw fuel after the desulfurization process that flows out from the desulfurization vessel in the desulfurizer 310.
A heat exchange device 160 is connected to the steam mixer 140, and the steam supplied from the heat exchange device 160 is mixed with the raw fuel after the desulfurization process flowing out from the desulfurizer 310. When a liquid fuel such as kerosene is used as the raw fuel, the raw fuel may be vaporized by the heat of superheated steam to form a raw material gas.

The reformer 620 is filled with a reforming catalyst such as a ruthenium (Ru) -based catalyst or a nickel (Ni) -based catalyst (not shown) and includes a burner unit 151 as a combustor.
The burner unit 151 is supplied with raw fuel from the raw fuel supply means 110 that branches on the upstream side of the desulfurization apparatus 300, and with fuel gas discharged from the fuel cell stack 200 described later. Then, the burner unit 151 burns at least one of the raw fuel and the fuel gas with the air supplied from the air supply blower 170, and converts the raw material gas, which is desulfurized and mixed with the water vapor, into the hydrogen-rich fuel gas. Reform.
The high-temperature combustion gas generated by the combustion of the burner unit 151 heats the reformer 620, is cooled by heat exchange, and is appropriately discharged into the outside air.
A pure water tank 180 that stores pure water 181 is connected to the heat exchange device 160 via a water supply path 183 having a transport pump 182, and pure water 181 is supplied from the pure water tank 180. Then, the heat exchange device 160 cools the combustion gas exhausted from the reformer 620 with the supplied pure water 181 and generates water vapor, and supplies the generated water vapor to the water vapor mixer 140. The pure water tank 180 may store pure water 181 that does not contain impurities such as distilled water, and may have a configuration in which, for example, tap water is purified and supplied as appropriate.

The CO converter 810 is connected in series to the reformer 620, and converts carbon monoxide (CO) contained in the hydrogen-rich reformed gas flowing out from the reformer 620.
The CO selective oxidizer 830 is connected in series to the CO converter 810, oxidizes CO contained in the reformed gas to carbon dioxide (CO ₂ ), and removes CO in the reformed gas.
The CO converter 810 and the CO selective oxidizer 830 may be integrated with the reformer 620. Furthermore, the steam mixer 140 and the heat exchange device 160 may be integrated. In addition to the CO converter 810 and the CO selective oxidizer 830, a device for adsorbing and removing CO may be provided.
The configuration from the raw fuel supply means 110 to the reforming unit 400 is configured as a fuel gas production apparatus 500.

A fuel cell stack 200 is connected to the reforming unit 400, and a fuel gas, which is a reformed gas from which CO is removed by steam reforming the raw material gas in the reforming unit 400, is supplied to the fuel cell stack 200.
The fuel cell stack 200 reacts hydrogen and oxygen to generate DC power. This fuel cell stack 200 is, for example, a solid polymer fuel cell, and is a fuel cell including a positive electrode 201, a negative electrode 202, and a polymer electrolyte membrane (not shown) disposed between the positive electrode 201 and the negative electrode 202. It is an aggregate. For example, air humidified by a humidifier (not shown) is supplied to the positive electrode 201 side, and hydrogen-rich fuel gas humidified via, for example, a humidifier (not shown) is supplied to the negative electrode 202 side. Then, hydrogen (fuel gas) reacts with oxygen in the air to generate water (pure water 181), and DC power is generated between the positive electrode 201 and the negative electrode 202. The fuel cell stack 200 may be configured to generate electricity by supplying air or fuel gas without being humidified.
The negative electrode 202 side is connected to the burner unit 151 of the reformer 620 as described above, and the surplus hydrogen content is supplied as fuel for the burner unit 151. A separator 185 is connected to the positive electrode 201 side. The separator 185 is supplied with air used for the reaction from the positive electrode 201 side, and is separated into air for the gas phase and water (pure water 181) for the liquid phase. The separated air is exhausted to the outside air. The separator 185 is connected to a pure water tank 180 and supplies the separated water (pure water 181) to the pure water tank 180.

Further, the fuel cell stack 200 is provided with a cooling device 187. The cooling device 187 is provided with a heat recovery device 187A attached to the fuel cell stack 200. A pure water tank 180 is connected to the heat recovery apparatus 187A via a circulation path 187D including a pump 187B and a heat exchanger 187C.
This circulation path 187D circulates the pure water 181 between the heat recovery device 187A and the pure water tank 180 by driving the pump 187B, cools the fuel cell stack 200 that generates heat accompanying power generation, and recovers heat. .
The heat exchanger 187C exchanges heat with the pure water 181 that has been circulated and the heat recovered by the heat recovery device 187A, for example, tap water. The tap water warmed by this heat exchange is directly supplied to other facilities such as a bath for effective use. In addition to heat exchange with tap water, it may be used effectively for other facilities such as generating electricity from heat obtained by heat exchange.

The fuel cell system 100 includes a control device (not shown) that controls the operation of the entire system.
This control device controls the supply amount of raw fuel, the combustion control of the burner unit 151 of the reformer 620, the supply amount control of pure water 181 for generating steam in the heat exchange device 160, the temperature management, and the management of the power generation amount And so on.

(Reforming unit)
Next, the configuration of the reforming unit 400 in the fuel cell system 100 described above will be described in detail.
FIG. 2 is a side sectional view showing a schematic configuration of the reforming unit in the fuel cell system. FIG. 3 is a side sectional view showing a schematic configuration of a combustion chamber portion of the reforming unit. FIG. 4 is a side sectional view showing a schematic configuration of a reforming unit of the reforming unit. FIG. 5 is an enlarged side sectional view showing a part of the reformer of the reforming unit. FIG. 6 is an enlarged side sectional view showing a part of the gas heat exchange section of the reforming unit. FIG. 7 is a plan view showing a protective tube attachment piece attached to the first reformer member of the reforming vessel. FIG. 8 is a plan view showing an assembled state of the first cylindrical member and the second cylindrical member of the gas heat exchange unit. FIG. 9 is a plan view showing a boiler of the reforming unit. FIG. 10 is a side view in which a part of the boiler of the reforming unit is cut away. FIG. 11 is a plan view showing a CO removing unit of the reforming unit. FIG. 12 is a bottom view showing the CO removing unit. FIG. 13 is a side cross-sectional view showing a CO removing unit of the reforming unit. FIG. 14 is an enlarged side sectional view showing a part of the CO removing unit. FIG. 15 is an enlarged side sectional view showing a connection portion between the CO transformer and the CO selective oxidizer. FIG. 16 is a side cross-sectional view showing an exhaust gas cooler of the CO removing unit. FIG. 17 is a bottom view showing an exhaust gas cooler of the CO removing unit.

As described above, the reforming unit 400 has an integrated configuration including the steam mixer 140, the heat exchange device 160, the reformer 620, the CO converter 810, and the CO selective oxidizer 830.
In addition, the heat exchange device 160 includes a boiler 650 and an exhaust gas cooler 840.
As shown in FIG. 2, the reforming unit 400 includes a unit main body portion 400A and a heat insulating portion (not shown) that covers the unit main body portion 400A. The unit main body 400A includes a reforming unit 600, a piping unit 700, and a CO removing unit 800. The unit main body 400A is connected to the reforming unit 600 via the piping unit 700 upward in the vertical direction with respect to the CO removal unit 800 placed and fixed on the bottom of a case body (not shown) that houses the fuel cell system 100. Are integrally connected.

  The reformer 600 is for reforming the raw material gas with steam, and includes a reformed outer case 610. The reformed exterior case 610 includes a cylindrical cylindrical case 611 having an open top and bottom surface, an upper case 612 that covers the upper surface of the cylindrical case 611 and is attached integrally, and a lower surface of the cylindrical case 611 that covers the lower surface. And a support pedestal portion 613 attached to the pedestal. The cylindrical case 611 is a substantially cylindrical member, and is formed, for example, in a substantially cylindrical shape using a steel plate or the like, and more specifically, is formed using a sheet-wound tube of a steel plate that is a tube material. The upper case 612 is formed in a substantially flat plate shape that is fitted and inserted into the inner periphery on the upper surface side of the cylindrical case 611, and a burner unit 151 described later is attached to the inner peripheral edge side to close the upper surface side of the cylindrical case 611. The support pedestal portion 613 is formed in a substantially flat plate shape that is fitted and inserted into the inner periphery of the lower end of the cylindrical case 611, and piping that communicates between the reforming portion 600 and the piping portion 700 and a gas heat exchanging portion 640 that will be described later. There is no air gap other than the protruding portion, and the reforming unit 600 and the piping unit 700 are separated and cut off.

In the reformed exterior case 610, a reformer 620, a gas heat exchange unit 640, and a boiler 650 are disposed.
The reformer 620 includes a combustion chamber 621, a burner unit 151, a reforming vessel 622, and a protective cover 623.
As shown in FIGS. 2, 4, and 5, the reforming vessel 622 has a bottomed cylindrical shape in which a combustion chamber portion 621 to which the burner unit 151 is attached is disposed on the inner peripheral side. A gas heat exchange unit 640 is integrally provided at a lower end portion that is one end side in the axial direction of the reforming vessel 622, and an inner peripheral surface of the reforming vessel 622 is covered on an inner peripheral side of the reforming vessel 622. A protective cover 623 is provided in the state. Further, a boiler 650 is disposed on the outer peripheral side of the gas heat exchange unit 640.

The combustion chamber section 621 heats the reformer 620 by the combustion of the burner unit 151. As shown in FIGS. 2 and 3, the combustion chamber section 621 is made of, for example, a steel plate and has an inner periphery of the upper case 612 of the reformed outer case 610. It has a combustion cylinder portion 621A formed in a cylindrical shape that is fitted and inserted on the side. A spiral flow portion 621A1 is integrally provided on the outer peripheral surface of the combustion cylinder portion 621A. The spiral flow portion 621A1 is not in contact with the inner peripheral surface of the combustion cylinder portion 621A, and the burner unit 151 that circulates between an inner peripheral surface of a protective cover 623 and an outer peripheral surface of the combustion cylinder portion 621A, which will be described later. Combustion gas is formed in a state of circulating spirally with respect to the central axis.
Further, the combustion cylinder portion 621A is provided with a positioning dowel 621B at a predetermined position on the upper end side which is one end in the axial direction so as to bulge inward by embossing or the like. Further, a support flange 621C is provided at the upper end, which is one end in the axial direction, of the combustion cylinder portion 621A. A bolt insertion hole 621E through which the mounting bolt 621D is inserted is formed in the support flange 621C.
Further, the combustion chamber portion 621 is integrally provided with a flame rectifying portion 621F. This flame rectifying part 621F has an attachment cylindrical part 621F1 whose outer diameter is substantially the same as the inner diameter of the combustion cylinder part 621A and is located on the upper end side of the combustion cylinder part 621A and attached integrally by welding or the like. . In addition, a funnel-shaped rectifying cylinder portion 621F2 having a diameter gradually decreasing in accordance with the tip end side is provided in series at the lower end which is one end in the axial direction of the mounting cylindrical portion 621F1. The flame rectifying unit 621F is positioned by a positioning dowel 621B of the combustion cylinder 621A, and the mounting cylinder 621F1 is integrally attached to a predetermined position on the inner peripheral side of the combustion cylinder 621A by welding or the like.

For example, as shown in FIG. 2, the burner unit 151 burns off-gas containing burner main body 661 formed by casting and unused hydrogen discharged from the raw fuel or the negative electrode 202 of the fuel cell stack 200 to form a flame. A burner section 662 having a plurality of combustion ports (not shown) for generating
The burner body 661 has a first air introduction part 661A in which air supplied from the air supply blower 170 is introduced as primary air, and a second air introduction part (not shown) in which supplied air is introduced as secondary air And an off-gas introduction part 661B for introducing and burning off-gas. In addition, a fuel supply pipe 661C to which raw fuel is supplied is connected to the first air introduction part 661A, and the supplied raw fuel is mixed with primary air, supplied to the burner body 661, and burned.
In the burner unit 151, a mounting flange 661E provided in a bowl shape on the burner body 661 is supported so as to further overlap the support flange 621C of the combustion chamber 621, and a mounting bolt 621D is screwed thereto. In this state, the upper end portion of the reformed exterior case 610 is closed, and the burner unit 151 is integrally provided.
The attached state of the burner unit 151 corresponds substantially to the upper end portion of the reforming vessel 622 while the lower end portion of the burner portion 662 is substantially located within the rectifying cylinder portion 621F2 of the flame rectifying portion 621F of the combustion chamber portion 621. Is in position.

The protective cover 623 heats the reforming vessel 622 with a predetermined temperature distribution while preventing partial overheating of the reforming vessel 622 due to the combustion gas of the burner unit 151. As shown in FIG. It is formed in a bottomed cylindrical shape so as to cover the inner peripheral side of the reforming vessel 622 formed in a cylindrical shape.
The protective cover 623 is made of a stainless steel plate having excellent heat resistance and corrosion resistance because the combustion gas of the burner unit 151 is hit. The protective cover 623 has a cylindrical protective tube portion 623A whose outer diameter is smaller than the inner diameter of the reforming vessel 622. A protective bottom portion 623B that closes the lower end surface of the cylindrical protective tube portion 623A is provided in series at the lower end edge of the cylindrical protective tube portion 623A. Furthermore, the upper end edge, which is the other axial end of the cylindrical protective tube portion 623A, is bent outward and further bent toward the lower end side so as to cover the upper end portion of the reforming vessel 622. A protective end 623C to be attached is provided.
A heat insulating member 624 is provided between the lower surface of the protective bottom 623B of the protective cover 623 and the reforming vessel 622.
The combustion gas burned in the burner unit 151 flows upward between the combustion chamber portion 621 and the protective cover 623 and travels around the upper portion of the reforming vessel 622, and the reforming vessel 622 and the cylindrical case 611 It circulates in the downward direction.

The reforming vessel 622 is filled with a reforming catalyst to steam reform the raw material gas, and has a bottomed cylindrical shape as shown in FIGS. That is, the reforming vessel 622 has a triple tube structure including a first cylindrical reformer member 622A, a second reformer member 622B, and a third reformer member 622C that have different diameters and are coaxially positioned. The first reformer member 622A, the second reformer member 622B, and the third reformer member 622C are arranged in this order from the inside.
As shown in FIG. 4 and FIG. 5, the first reformer member 622A is a series of a substantially cylindrical first reforming cylinder portion 622A1 and a lower end that is one end of the first reforming cylinder portion 622A1 in the axial direction. And a modified bottom plate portion 622A2 that closes the lower end surface of the first modified cylinder portion 622A1, and is formed in a bottomed cylindrical shape.
The second reformer member 622B includes a substantially cylindrical second reforming cylinder portion 622B1 having an inner diameter larger than the outer diameter of the first reforming cylinder portion 622A1, and the axial direction of the second reforming cylinder portion 622B1. It has a second reforming flange portion 622B2 that protrudes inwardly toward the lower end edge, which is one end edge, inwardly, and a gas heat exchanging portion 640 integrally connected to the inner peripheral edge, and is formed in a substantially cylindrical shape. ing. The second modified flange portion 622B2 is provided with a positioning dowel portion 622B3 so as to bulge upward by embossing or the like.
The third reformer member 622C has a substantially cylindrical third reforming cylinder portion 622C1 whose inner diameter is larger than the outer diameter of the second reforming cylinder portion 622B1, and the axial direction of the third reforming cylinder portion 622C1. It has a third modified flange portion 622C2 that protrudes inward from the lower end edge in a flange shape, and a gas heat exchanging portion 640 that is integrally connected to the inner peripheral edge, and is formed in a substantially cylindrical shape.

As shown in FIGS. 2, 4 and 5, the reformer vessel 622 includes an upper outer peripheral edge of the first reformer cylinder portion 622A1 of the first reformer member 622A, and a third reformer member 622C. A reforming ring end plate 622D is provided between the third reforming cylinder portion 622C1 and the inner peripheral edge at the upper end.
The modified ring end plate 622D is provided with a joint bent portion 622D1 by bending the outer peripheral edge and the inner peripheral edge in the same direction, and the modified ring end plate 622D includes the first modified cylindrical portion 622A1 and the third modified portion. It is formed in a U-shaped cross section so as to be surface-bonded to the cylindrical portion 622C1. By this reforming ring end plate 622D, the upper ends of the first reformer member 622A and the third reformer member 622C are connected, and the upper end of the reforming vessel 622 covered with the protective end 623C of the protective cover 623. Block the part.
The reforming ring end plate 622D is provided with a sensor arrangement hole 622D2 through which a sensor protection tube 622E for arranging a temperature sensor (not shown) is passed.

Further, the reforming vessel 622 is provided on the outer peripheral surface of the upper end portion of the first reforming cylinder portion 622A1 of the first reformer member 622A, and the second reforming cylinder portion 622B1 of the second reformer member 622B. An upper reforming partition member 622F that protrudes in a bowl shape toward the inner peripheral surface of the upper end portion and substantially closes the space between the first reformer member 622A and the second reformer member 622B is provided.
As shown in FIGS. 4 and 5, the upper reforming partition member 622F has an annular mounting pipe portion 622F1 whose inner peripheral surface is attached to the outer peripheral surface of the first reforming cylinder portion 622A1 of the first reformer member 622A. And the lower end edge of the mounting pipe part 622F1 is bent outwardly in a bowl shape, and the front end edge is formed on the inner peripheral surface of the second modified cylinder part 622B1 via a gap in consideration of the clearance due to thermal expansion. And an upper partitioning rod portion 622F2 facing each other. The upper divider 622F2 is formed with a plurality of gas flow holes 622F3 so that the reformed gas can flow.
Further, a sensor through-hole 622F4 through which the sensor protection tube 622E is passed is provided in the upper partition rod portion 622F2 of the upper reforming partition member 622F.
Further, as shown in FIGS. 4 and 7, the sensor protection tube 622E is penetrated through the reforming vessel 622 at the outer peripheral surface of the first reforming cylinder portion 622A1 of the first reformer member 622A. A plurality of protective tube attachment pieces 622E2 each having a sensor insertion hole 622E1 and holding the sensor protective tube 622E are provided.
Instead of providing the sensor protection tube 622E, for example, a temperature sensor may be attached to the first reformer member 622A or the second reformer member 622B.

Further, as shown in FIGS. 2, 4 and 5, the reformer vessel 622 is attached to the second reformer flange portion 622B2 of the second reformer member 622B and is located above the first reformer member. A lower reforming partition member 622G is provided so as to protrude in a cylindrical shape toward 622A.
As shown in FIGS. 4 to 6, the lower reforming partition member 622G includes a partition tube portion 622G1 whose inner diameter is larger than the outer diameter of the first reformed tube portion 622A1 in consideration of clearance such as thermal expansion. One end side in the axial direction of the partition tube portion 622G1 is formed in a substantially cylindrical shape having a partition mounting flange portion 622G2 that protrudes inwardly in a flange shape and is attached to the second modified flange portion 622B2 by welding or the like. Yes.
Further, the lower reforming partition member 622G is formed with a plurality of source gas flow holes 622G3 through which the source gas can flow in a curved portion that continues from the partition tube portion 622G1 to the partition mounting flange portion 622G2. This source gas flow hole 622G3 is formed so that the source gas flows well with a flow resistance smaller than the flow resistance flowing through the clearance between the partition tube portion 622G1 and the first reforming tube portion 622A1.
The partition mounting flange portion 622G2 is provided with a partition positioning hole portion 622G4 that engages with the positioning dowel portion 622B3 of the second reforming flange portion 622B2.

The reforming vessel 622 receives the raw material gas from the gas heat exchanging unit 640 by the reforming bottom plate portion 622A2 of the first reformer member 622A, the lower reforming partition member 622G, and the gas heat exchanging unit 640. An inflowing source gas inflow chamber 622H1 is defined. The reforming vessel 622 includes a first reforming cylinder portion 622A1 of the first reformer member 622A, a second reforming cylinder portion 622B1 of the second reformer member 622B, and an upper reforming partition member 622F. The reforming chamber 622H2 filled with the reforming catalyst is partitioned by the lower reforming partition member 622G. Further, the reforming vessel 622 includes a second reforming cylinder portion 622B1 of the second reformer member 622B, a third reforming cylinder portion 622C1 of the third reformer member 622C, and a reforming ring end plate 622D. The reformed gas flow path 622H3 through which the reformed gas flows is defined by the first reformed cylinder portion 622A1 of the first reformed cylinder portion 622A1, the upper reforming partition member 622F, and the gas heat exchange unit 640. ing.
The source gas inflow chamber 622H1 and the reforming chamber 622H2 communicate with each other through the source gas flow hole 622G3 of the lower reforming partition member 622G, and the source gas flowing into the source gas inflow chamber 622H1 flows into the reforming chamber 622H2. Further, the reforming chamber 622H2 and the reformed gas flow path 622H3 communicate with each other through the gas flow holes 622F3 of the upper reforming partition member 622F, and the reformed gas generated by steam reforming the raw material gas in the reforming chamber 622H2 is generated. It flows through the reformed gas flow path 622H3 and flows into the gas heat exchange unit 640 again.
The reformer 620 is heated by the combustion gas of the burner unit 151, and the reforming chamber 622H2 of the reforming vessel 622 is heated at a temperature distribution in which the lower end where the raw material gas flows is slightly lower than the upper end to prevent coking. However, the combustion chamber portion 621, the burner unit 151, and the reforming vessel 622 are formed so that the reforming process can be efficiently performed in the entire region of the reforming chamber 622H2. The reforming vessel 622 is not limited to a cylindrical shape, and may be a polygonal cylindrical shape, an elliptical cylindrical shape, a star cylindrical shape, or the like.

The gas heat exchanging unit 640 exchanges heat between the raw material gas and the reformed gas. As shown in FIGS. 2 and 4 to 6, the gas heat exchanging unit 640 is coaxial with the reforming vessel 622, and the reforming vessel 622. It is arrange | positioned vertically below.
This gas heat exchanging section 640 has a triple tube structure including a first cylindrical member 642A, a second cylindrical member 642B, and a third cylindrical member 642C that have different diameters and are coaxially positioned, and the first cylindrical member from the inside. 642A, the second cylindrical member 642B, and the third cylindrical member 642C are arranged in this order.

The first cylindrical member 642A has an inverted U-shaped cross section that opens at the lower end side that is one end in the axial direction. As shown in FIGS. 4, 6, and 8, the first cylindrical member 642A has a cylindrical first cylindrical portion 642A1 and the first cylindrical portion 642A. The cylindrical portion 642A1 has a cylindrical top plate portion 642A2 that is provided in series at the upper end on the other end side in the axial direction and closes the upper end surface of the first cylindrical portion 642A1, and is formed in a cylindrical shape.
At the center of the top surface of the cylindrical top plate portion 642A2, it is bent upward and is in contact with and supported by the reforming bottom plate portion 622A2 of the first reformer member 622A of the reforming vessel 622 when the reforming unit 400 is assembled. A reformer stopper 642A3 is provided. By this reformer stopper 642A3, the raw material gas inflow chamber 622H1 of the reforming vessel 622 is partitioned.

The second cylindrical member 642B is a bottomed cylindrical shape having a U-shaped cross section, and has a cylindrical second cylindrical portion 642B1 having an inner diameter larger than the outer diameter of the first cylindrical portion 642A1, and a lower end in the axial direction of the second cylindrical portion 642B1. And a cylindrical bottom plate portion 642B2 that is provided in series and closes the lower end surface of the second cylindrical portion 642B1.
The cylindrical bottom plate portion 642B2 is provided with a source gas supply through hole 642B5 that is connected to the steam mixer 140 and penetrates the source gas supply pipe 642D through which the source gas mixed with the steam flows from the steam mixer 140. Yes. The source gas supplied from the source gas supply pipe 642D flows into a space surrounded by the second cylindrical member 642B and the first cylindrical member 642A, that is, a source gas inflow space 642E1.
The second cylindrical portion 642B1 is provided with six support dowel portions 642B3 which are located on the lower end side and bulge inward by embossing or the like, which are divided into six equal parts in the circumferential direction. These support dowels 642B3 are formed to bulge so that the lower end edge of the first cylindrical member 642A abuts and can support the first cylindrical member 642A. Further, in the second cylindrical portion 642B1, a gap dowel portion 642B4 that is located on the upper end side from the position of the support dowel portion 642B3 and bulges inward at a predetermined height by embossing or the like is provided in the circumferential direction. It is provided at a position that divides into six equal parts. These gap dowel portions 642B4 are in contact with the outer peripheral surface of the first cylindrical portion 642A1 supported by the support dowel portion 642B3, and are predetermined between the outer peripheral surface of the first cylindrical portion 642A1 and the inner peripheral surface of the second cylindrical portion 642B1. , For example, a gap of 0.5 mm is formed in this embodiment. This gap serves as a raw material gas flow path 642E2 through which the raw material gas flows and communicates with the raw material gas inflow space 642E1.
Here, if the gap between the source gas flow paths 642E2 is narrower than 0.1 mm, there is a possibility that the flow path is closed due to a difference in thermal expansion between the first cylindrical portion 642A1 and the second cylindrical member 642B1. On the other hand, when the width is larger than 10 mm, the differential pressure in the gap portion between the first cylindrical portion 642A1 and the second cylindrical portion 642B1 becomes small, and there is a possibility that inconvenience that drift occurs in the circumferential direction may occur. For these reasons, it is preferable that the gap of the source gas flow path 642E2 is set to 0.1 mm or more and 10 mm or less. Furthermore, it is more preferable to set to 0.5 mm or more and 2.0 mm or less.
The support dowel portion 642B3 and the gap dowel portion 642B4 are not limited to the configuration provided at a position equally divided into six in the circumferential direction, and any one that can reliably support the first cylindrical member 642A and forms a uniform gap in the circumferential direction. It can be formed in numbers or shapes.
The upper end portion of the second cylindrical portion 642B1 is connected to the inner peripheral edge of the second reforming flange portion 622B2 of the reforming vessel 622, and the source gas flow path 642E2 communicates with the source gas inflow chamber 622H1 of the reforming vessel 622. To do.

The third cylindrical member 642C has a bottomed cylindrical shape with a U-shaped cross section, and has a cylindrical third cylindrical portion 642C1 having an inner diameter larger than the outer diameter of the second cylindrical portion 642B1, and a lower end in the axial direction of the third cylindrical portion 642C1. And a heat exchange bottom plate portion 642C2 that is provided in series and closes the lower end surface of the third cylindrical portion 642C1.
The third cylindrical portion 642C1 is provided with a gap dowel portion 642C3 that bulges inward at a predetermined height by embossing or the like at a position that divides into six equal parts in the circumferential direction. These gap dowel portions 642C3 are in contact with the outer peripheral surface of the second cylindrical portion 642B1, and have a predetermined width, for example, 0.1 mm or more, between the outer peripheral surface of the second cylindrical portion 642B1 and the inner peripheral surface of the third cylindrical portion 642C1. A gap of 10 mm or less and 0.5 mm in this embodiment is formed.
The upper end portion of the third cylindrical portion 642C1 is connected to the inner peripheral edge of the third reforming flange portion 622C2 of the reforming vessel 622. A reformed gas flow passage 642E3 communicating with the reformed gas channel 622H3 of the reforming vessel 622 is formed between the outer peripheral surface of the second cylindrical portion 642B1 and the inner peripheral surface of the third cylindrical portion 642C1. If the gap between the reformed gas flow passages 642E3 is narrower than 0.1 mm, there is a possibility that the flow path is blocked due to a difference in thermal expansion between the second cylindrical portion 642B1 and the third cylindrical portion 642C1. On the other hand, if the width is larger than 10 mm, the differential pressure in the gap portion between the second cylindrical portion 642B1 and the third cylindrical portion 642C1 becomes small, and there is a possibility that inconvenience arises in that drift occurs in the circumferential direction. For these reasons, the clearance of the reformed gas flow passage 642E3 is preferably set to 0.1 mm or more and 10 mm or less. Furthermore, it is more preferable to set to 0.5 mm or more and 2.0 mm or less.
The gap dowel portion 642C3 is provided at a position that does not coincide with the support dowel portion 642B3 and the gap dowel portion 642B4 of the second cylindrical member 642B, and reliably contacts the second cylindrical member 642B so as to have a reformed gas flow passage with a predetermined gap. Provided to form 642E3. The gap dowel portion 642C3 is not limited to being divided into six equal parts in the circumferential direction, and may be formed with a number or shape that can reliably support the first cylindrical member 642A and form a uniform gap in the circumferential direction.
The heat exchange bottom plate portion 642C2 is provided with a reformed gas outflow through hole 642C4 through which the reformed gas outflow pipe 642F passes. This reformed gas outflow pipe 642F communicates with the reformed gas flow passage 642E3, flows into the gas heat exchange section 640 from the reforming vessel 622, and reforms while exchanging heat with the source gas flowing through the source gas channel 642E2. The reformed gas flowing through the gas flow passage 642E3 is caused to flow out of the gas heat exchange unit 640.
In addition, since the first cylindrical member 642A, the second cylindrical member 642B, and the third cylindrical member 642C are formed in a substantially cup shape, they can be easily manufactured by press molding, can be easily assembled, and the manufacturing cost can be reduced. Further, since the support dowel portion 642B3, the gap dowel portion 642B4, and the gap dowel portion 642C also have a shape protruding to the inner peripheral side, dowel processing can be easily performed.

Although the boiler 650 of the reforming unit 600 will be described in detail later, water (pure water 181) heated from the exhaust gas cooler 840 via the CO removal heat exchange unit 850 is exchanged with the combustion gas of the burner unit 151. Heat to produce water vapor. The boiler 650 is configured in a double tube structure as shown in FIGS. The boiler 650 includes a reformed water inner pipe 651 through which pure water 181 is circulated, and an exhaust air duct outer pipe 652 into which the reformed water inner pipe 651 is inserted.
One end of the exhaust air passage outer pipe 652 is opened in the axial direction, and the other end in the axial direction is fitted and fixed to the heat exchange hole 613A of the support base 613 by welding or the like, and has a predetermined diameter smaller than the inner diameter of the cylindrical case 611. It is formed in a spiral shape with a curvature radius of. That is, the exhaust air passage outer pipe 652 is disposed in a state where the upper surface side and the lower surface side of the support pedestal 613 communicate with each other, and the combustion gas burned in the burner unit 151 flows from the inner peripheral side of the reforming vessel 622. The outer peripheral side is circulated downward through the upper end side, and is circulated from the upper surface side of the support pedestal portion 613 to the lower surface side of the support pedestal portion 613 through the inside of the exhaust air duct outer tube 652.
The reformed water inner pipe 651 has one end side in the axial direction extending from one end where the exhaust air path outer pipe 652 is opened, and the other end side in the axial direction is connected to the support pedestal 613 in addition to the exhaust air path outer pipe 652. In the state extending from the end, it is arranged coaxially in the exhaust air duct outer tube 652. Although details will be described later, in terms of heat exchange efficiency between pure water 181 and the combustion gas, the reformed water inner pipe 651 is disposed substantially coaxially in the exhaust air duct outer pipe 652. However, a configuration in which a separate member such as a pipe or a spacer for positioning on the same axis is provided may be used. As will be described in detail later, the reformed water inner pipe 651 has one end side in the axial direction serving as an end corresponding to the outflow side of water vapor generated by heat exchange passing through the support pedestal 613 and the support pedestal 613. It is arranged in a state of extending to the lower surface side of the water and connecting to the steam mixer 140. The penetration portion of the support pedestal 613 of the modified water inner pipe 651 is sealed in a substantially airtight manner by welding or brazing. An exhaust gas cooler 840 to which pure water 181 as reforming water is supplied is described later in detail on the other end side in the axial direction of the reforming water inner pipe 651 extending to the lower surface side of the support pedestal 613. The CO removal heat exchanging unit 850 connected to is connected, and the exhaust gas cooler 840 and the pure water 181 heated by heat exchange in the CO removal heat exchanging unit 850 are circulated in the reformed water inner pipe 651. The boiler 650 heat-exchanges the pure water 181 flowing through the reformed water inner pipe 651 with the combustion gas flowing through the exhaust air duct outer pipe 652 to generate water vapor.

The piping unit 700 of the reforming unit 400 includes a piping outer case 710 as shown in FIG. The pipe outer case 710 is formed in a cylindrical shape. In this pipe outer case 710, a CO removing portion 800 is fitted and inserted into the lower end side which is one end in the axial direction, and is integrally connected by welding or brazing. Further, the outer periphery of the support pedestal 613 of the reforming unit 600 is fitted and inserted into the pipe outer case 710 on the upper end side which is the other end in the axial direction, and is integrally connected by welding or brazing.
A raw fuel pipe 720 through which the raw fuel after desulfurization flowing out from the outlet of the desulfurization vessel in the desulfurizer 310 flows is passed through the pipe outer case 710. The raw fuel pipe 720 is connected to the steam mixer 140, and the steam from the boiler 650 is mixed.
Further, an exhaust gas pipe 730 extending from the CO removing unit 800 is penetrated through the pipe outer case 710, and the combustion gas of the burner unit 151 is discharged out of the reforming unit 400. That is, the inner peripheral side of the pipe outer case 710 communicates with the inner peripheral side of the exhaust air duct outer pipe 652 through which the combustion gas of the burner unit 151 in the boiler 650 flows, and the combustion gas flows in. As will be described in detail later, this combustion gas flows through the CO removing unit 800 connected to the pipe outer case 710, and is further cooled by heat exchange, and is discharged from the CO removing unit 800 to the outside of the reforming unit 400 through the exhaust gas pipe 730. Exhaust as exhaust gas.

As shown in FIG. 2, the CO removal unit 800 includes a CO converter 810, a heat treatment means 820, a CO selective oxidizer 830, an exhaust gas cooler 840, a CO removal heat exchange unit 850, and a base case 860. I have.
The reforming outer case 610, the piping outer case 710, a part of the CO transformer 810, and the base case 860 constitute an outer case of the unit main body 400A.
The pedestal case 860 is formed in a bottomed cylindrical shape having a diameter substantially the same as that of the pipe exterior case 710, and a CO transformer 810 is fitted and inserted into the open upper end edge, as will be described in detail later. They are connected together by brazing or the like.

As shown in FIGS. 2 and 13 to 15, the CO removing unit 800 includes a substantially cylindrical first CO removing member 801, a second CO removing member 802, It has a quadruple tube structure including a CO removing member 803 and a fourth CO removing member 804, and from the outside, a first CO removing member 801, a second CO removing member 802, a third CO removing member 803, and a fourth CO The removing members 804 are arranged in this order.
As shown in FIGS. 2 and 11 to 15, a substantially flat plate-like ring is formed between both axial edges of the first CO removing member 801 and both axial edges of the second CO removing member 802. The first CO removing member 801, the second CO removing member 802, and the outer circumferential end plate 805 constitute a cylindrical CO transformer 810.
Further, between the both end edges in the axial direction of the third CO removal member 803 and the both end edges in the axial direction of the fourth CO removal member 804, a substantially flat plate-shaped inner peripheral side end plate 806 is connected, The third CO removing member 803, the fourth CO removing member 804, and the inner peripheral side end plate 806 constitute a cylindrical CO selective oxidizer 830 coaxially positioned inside the cylindrical CO transformer 810.
Further, a plurality of connection support members 807 are connected in a bridging state between both end edges in the axial direction of the second CO removal member 802 and both end edges in the axial direction of the third CO removal member 803. The unit 810 and the CO selective oxidizer 830 are integrally connected. The connection support member 807 is integrally provided with a spacer portion 807A that maintains a gap between the second CO removal member 802 and the third CO removal member 803. Further, between the second CO removal member 802 and the third CO removal member 803, a heat treatment means 820 is constructed in which the upper end side communicates with the pipe outer case 710 of the pipe section 700 and the lower end side communicates with the base case 860.
The CO removing unit 800 is not limited to a cylindrical shape, and may be a polygonal cylindrical shape, an elliptical cylindrical shape, a star cylindrical shape, or the like.

In the CO converter 810, as shown in FIGS. 2 and 13 to 15, CO conversion partition plates 811 are provided on the upper and lower sides in the axial direction. These CO metamorphic partition plates 811 are provided in a bowl shape from the outer peripheral surface of the second CO removing member 802 toward the inner peripheral surface of the first CO removing member 801, and are provided with a plurality of holes through which the reformed gas can flow. It has been. By these CO shift dividing plates 811, the gas diffusion region 812, the CO shift reaction region 813 filled with the CO shift catalyst, and the gas converging region 814 are inserted into the CO shift converter 810 from the lower part in the axial direction. A compartment is formed so that the reformed gas can flow.
Note that a clearance such as thermal expansion is provided between the CO-transforming partition plate 811 and the inner peripheral surface of the first CO removing member 801.
The CO converter 810 is connected to a reformed gas outflow pipe 642F connected to the gas heat exchange unit 640. The reformed gas outflow pipe 642F is connected to the gas diffusion region 812 through the outer peripheral end plate 805 and the CO conversion partition plate 811 on the upper end side of the CO converter 810.
In addition, one end of a connecting pipe 740 is connected to the CO transformer 810, which is positioned on the opposite side to the position where the reformed gas outflow pipe 642F passes through the outer peripheral end plate 805 on the upper end side. Yes. The connecting pipe 740 is bent in a U shape, and the other end is connected to an inner peripheral end plate 806 on the upper end side of the CO selective oxidizer 830. Further, the CO transformer 810 is provided with an air introduction pipe 750 that is coaxially fitted and inserted into one end of the connecting pipe 740 to be connected so as to penetrate from the outer peripheral side of the outer end plate 805 on the upper end side. Yes. The air introduction pipe 750 is provided with a blower (not shown) and the like, and supplies a gas containing oxygen, for example, air, into the communication pipe 740.
Then, the reformed gas flowing out from the gas heat exchange unit 640 and flowing through the reformed gas outlet pipe 642F flows into the gas diffusion region 812 of the CO converter 810, and flows through the CO shift reaction region 813 to enter the reformed gas. The CO is transformed, and the air supplied from the air introduction pipe 750 is mixed from the gas converging region 814 through the communication pipe 740 and flows to the CO selective oxidizer 830.
The CO converter 810 is provided with a CO conversion cooling pipe 851 that constitutes the CO removal heat exchange unit 850, located on the lower end side of the CO conversion reaction region 813. The shift reaction that undergoes CO conversion is an exothermic reaction, and since the reaction proceeds immediately by the CO conversion catalyst, the reformed gas on the lower end side of the CO conversion reaction region 813 that tends to increase in temperature due to the exothermic reaction flows. A CO shift cooling pipe 851 is disposed in the upstream region. As will be described in detail later, this CO shift cooling pipe 851 is connected to the reformed water inner pipe 651 of the boiler 650 through the heat treatment means 820, and circulated water (pure water) heated by heat exchange with the reformed gas. 181) is supplied to boiler 650.
Further, the CO transformer 810 is provided with a temperature sensor protective tube 815 that houses a temperature sensor (not shown) that measures the temperature in the gas diffusion region 812.

Similar to the CO converter 810, the CO selective oxidizer 830 is provided with CO selective oxidation partition plates 831 on the upper and lower sides in the axial direction inside. These CO selective oxidation partition plates 831 are provided in a bowl shape from the outer peripheral surface of the fourth CO removal member 804 toward the inner peripheral surface of the third CO removal member 803, and have a plurality of holes through which the reformed gas can flow. Is provided. By these CO selective oxidation partition plates 831, in the CO selective oxidizer 830, a diffusion region 832 that communicates with the connecting pipe 740 from the upper part in the axial direction, and a CO selective oxidation reaction region 833 filled with a CO selective oxidation catalyst, The convergence region 834 is partitioned so that the reformed gas can flow therethrough.
A clearance such as thermal expansion is provided between the CO selective oxidation partition plate 831 and the inner peripheral surface of the third CO removing member 803.
The CO selective oxidizer 830 is connected to a lower end plate 806 with a fuel gas pipe 760 communicating with an internal convergence region 834.
Then, the reformed gas that is mixed with air from the air inlet pipe 750 from the CO converter 810 and flows through the connecting pipe 740 flows into the diffusion region 832 of the CO selective oxidizer 830 and flows through the CO selective oxidation reaction region 833. As a result, CO in the reformed gas is oxidized to carbon dioxide (CO ₂ ), CO in the reformed gas is removed, and the fuel gas flows out of the reforming unit 400 from the fuel gas pipe 760.
The CO selective oxidizer 830 is provided with a CO selective oxidation cooling pipe 852 that constitutes the CO removal heat exchange unit 850. The CO selective oxidation cooling pipe 852 is spirally disposed in the CO selective oxidation reaction region 833, and cools the CO selective oxidation reaction region 833. The CO selective oxidation cooling pipe 852 is arranged so that the spiral pitch is narrower on the upper side into which the reformed gas flows and has a wider pitch on the lower side. Further, the CO selective oxidation cooling pipe 852 is disposed so as to be displaced from the approximate center to the outer peripheral side in the radial direction of the CO selective oxidation reaction region 833. That is, although details will be described later, the pure water flow path 845 of the exhaust gas cooler 840 is positioned on the inner peripheral side of the CO selective oxidizer 830, and the high temperature CO converter 810 is positioned on the outer peripheral side of the CO selective oxidizer 830. The CO selective oxidizer 830 is arranged so as to be displaced from the center in the radial direction to the outer peripheral side to cool the whole in a well-balanced manner. The CO selective oxidation cooling pipe 852 has one end connected to the exhaust gas cooler 840 and the other end connected to a CO shift cooling pipe 851. Then, the water (pure water 181) heated by the exhaust gas cooler 840 flows into the CO selective oxidation cooling pipe 852, is heated by heat exchange with the reformed gas flowing through the CO selective oxidation reaction region 833, and is coupled with CO. It flows out into the CO conversion cooling pipe 851 of the vessel 810.

As described above, the heat treatment means 820 provided between the CO converter 810 and the CO selective oxidizer 830 communicates the upper end side with the pipe outer case 710 of the pipe section 700 and the lower end side with the base case 860. The combustion gas of the burner unit 151 that has flowed into the pipe outer case 710 is formed so as to be able to flow from the upper end side to the pedestal case 860 on the lower end side.
This heat treatment means 820 is provided with a C-shaped radiation preventing plate 821 in a plan view having a slit 821A in the axial direction, located substantially in the center in the radial direction of the CO removing portion. The radiation preventing plate 821 is positioned and held at the upper edge and the lower edge by a positioning notch 807B provided in the spacer portion 807A of the connection support member 807. Note that the positioning cut portion 807B is provided in a state of holding the radiation preventing plate 821 with a clearance in consideration of thermal expansion and the like. The radiation preventing plate 821 is positioned and held in the vicinity of the edge of the slit 821A serving as a free end by the positioning cut portion 807B of the spacer portion 807A of the connection support member 807, and is supported so as not to rattle.
The end of the CO conversion cooling pipe 851 extending from the CO converter 810 is piped in the slit 821A of the radiation prevention plate 821 so as to penetrate the heat treatment means 820 in the axial direction, and is connected to the boiler 650.
A CO removal heat exchange section 850 is configured by the CO shift cooling pipe 851 connected to the boiler 650 and the CO selective oxidation cooling pipe 852 connected to the CO shift cooling pipe 851 and to the exhaust gas cooler 840. .

The exhaust gas cooler 840 is supplied with pure water 181 via a water supply path 183, exchanges heat between the combustion gas of the burner unit 151 and the pure water 181 and sufficiently cools and exhausts the combustion gas. The exhaust gas cooler 840 is formed in a celestial cylindrical shape as shown in FIGS. 2, 13, and 16.
That is, the exhaust gas cooler 840 has a triple pipe structure including a first cooler member 841, a second cooler member 842, and a third cooler member 843 that have different diameters and are positioned coaxially, and the first cooler member 841 from the outside. The second cooler member 842 and the third cooler member 843 are arranged in this order.

The first cooler member 841 has an inverted U-shaped cross-section that opens at the lower end serving as one end in the axial direction, and has a cylindrical first cooler cylindrical portion 841A and the other end side in the axial direction of the first cooler cylindrical portion 841A. And a first cooler top plate portion 841B that is provided in series at the upper end and closes the upper end surface of the first cooler cylindrical portion 841A, and is formed in a cylindrical shape.
Further, a stepped cooler stepped portion 841C having a diameter larger than that of the first cooler cylindrical portion 841A is bent and formed at the lower end portion of the first cooler cylindrical portion 841A. A water supply path 183 is connected to the cooler stepped portion 841C so as to communicate with the inner peripheral surface. Note that the cooler step portion 841C is bent so that the step portion is curved.
Further, the first cooler cylindrical portion 841A is provided with a first cooler dowel portion 841D that bulges inward at a predetermined height by embossing or the like at a position that divides into six equal parts in the circumferential direction. . These first cooler dowel portions 841D are in contact with the outer peripheral surface of the second cooler member 842, and have a predetermined width between the inner peripheral surface of the first cooler member 841 and the outer peripheral surface of the second cooler member 842, for example, 0. A pure water flow path 845 having a gap of 1 mm or more and 10 mm or less, and 0.5 mm in this embodiment is defined.
Here, when the gap between the pure water flow paths 845 becomes narrower than 0.1 mm, there is a possibility that the flow path is blocked due to a difference in thermal expansion between the first cooler cylindrical portion 841A and a second cooler cylindrical portion 842A described later. . On the other hand, when the width is larger than 10 mm, there is a concern that the differential pressure in the gap portion between the first cooler cylindrical portion 841A and the second cooler cylindrical portion 842A becomes small and a drift occurs. For these reasons, it is preferable to set the clearance of the pure water channel 845 to be 0.1 mm or more and 10 mm or less.
The clearance of the pure water flow path 845 is preferably increased in order to realize stable boiling of the flowing pure water 181. However, if the clearance of the pure water flow path 845 is reduced, the pure water flow path 845 is more pure. The pressure loss of the water flow path 845 increases, and the power loss of the transfer pump 182 increases. For this reason, it is more preferable to set to 0.5 mm or more and 2.0 mm or less.
Further, the gap between the pure water channels 845 is preferably smaller than the exhaust gas discharge channel 847 described later. This is because the flow rate of pure water 181 is less than the flow rate of combustion gas, so that the pure water flow path 845 is narrower than the exhaust gas discharge flow path 847 and the flow rate of the pure water 181 is increased to obtain good heat exchange performance. Because it can.
The first cooler top plate portion 841B is provided with a cooler dome portion 841E to which an end portion of a CO selective oxidation cooling pipe 852 extending from the CO selective oxidizer 830 is connected. The cooler dome portion 841E is provided with a water connection flange 841E1 for connecting the end portion of the CO selective oxidation cooling pipe 852 in a state of communicating with the inner surface side of the first cooler member 841.
Further, the first cooler top plate portion 841B is provided with a gas connection flange 841F that protrudes upward in a cylindrical shape and is connected in a state where the exhaust gas pipe 730 communicates with the inner surface side of the first cooler member 841. .

The second cooler member 842 has a reverse U-shaped cross-section with an open lower end serving as one end in the axial direction, and has a cylindrical second cooler cylindrical portion 842A and the other end side in the axial direction of the second cooler cylindrical portion 842A. And a second cooler top plate portion 842B which is provided in series at the upper end and closes the upper end surface of the second cooler cylindrical portion 842A, and is formed in a cylindrical shape.
The lower end edge of the second cooler cylindrical portion 842A is provided with a cooler connection flange 842C that protrudes in a flange shape as a step on the outer peripheral side and is connected to the lower end edge of the cooler step portion 841C of the first cooler cylindrical portion 841A. Yes. The cooler connecting flange 842C, the cooler stepped portion 841C of the first cooler cylindrical portion 841A, and the second cooler cylindrical portion 842A provide a pure water retention portion 846 as a water storage portion communicating with the water supply path 183 and the pure water flow path 845. A compartment is formed. The pure water 181 supplied from the water supply path 183 flows into the pure water retention part 846 and flows through the pure water passage 845 to the CO selective oxidation cooling pipe 852.
The pure water staying portion 846 is bent so that the stepped portion of the cooler stepped portion 841C is curved. Therefore, the pure water 181 that has flowed into the pure water staying portion 846 is compared with the curved inner surface of the cooler stepped portion 841C. Therefore, even if bubbles are generated smoothly and smoothly flow into the pure water flow path 845, the pulsating flow can be suppressed. The pure water retention unit 846 purges the reforming vessel 622, the CO converter 810, and the CO selective oxidizer 830 with water vapor when the entire amount of the pure water 181 in the pure water retention unit 846 becomes steam. The volume of pure water 181 that can be generated is formed in a volume that can be retained.
Further, the second cooler cylindrical portion 842A is provided with a second cooler dowel portion 842D that bulges inward at a predetermined height by embossing or the like at a position that divides into six equal parts in the circumferential direction. . These second cooler dowel portions 842D are in contact with the outer peripheral surface of the third cooler member 843, and have a predetermined width between the inner peripheral surface of the second cooler member 842 and the outer peripheral surface of the third cooler member 843. In this embodiment, the exhaust gas discharge passage 847 is defined as a gap of 1 mm or more and 10 mm or less, and 1 mm.
Here, when the gap between the exhaust gas discharge passages 847 becomes narrower than 0.1 mm, the passages may be blocked by the difference in thermal expansion between the second cooler cylindrical portion 842A and the third cooler cylindrical portion 843A described later, or soot may be generated. There is a risk of inconvenience such as obstruction. On the other hand, when the width is larger than 10 mm, the differential pressure in the gap portion between the second cooler cylindrical portion 842A and the third cooler cylindrical portion 843A becomes small, which may cause a disadvantage that a drift occurs in the circumferential direction. For these reasons, the clearance of the exhaust gas discharge passage 847 is preferably set to 0.1 mm or more and 10 mm or less. Furthermore, it is more preferable to set to 0.5 mm or more and 2.0 mm or less.
The first cooler dowel portion 841D and the second cooler dowel portion 842D are provided at different positions in the axial direction that do not coincide with each other, so that the pure water channel 845 is surely defined. And these 1st cooler dowel parts 841D and 2nd cooler dowel parts 842D are not restricted to the composition divided into 6 equally in the peripheral direction like the above-mentioned support dowel part 642B3, gap dowel part 642B4, and gap dowel part 642C3, It can be formed in any number or shape that forms uniform gaps in the circumferential direction.
Further, the second cooler top plate portion 842B is provided with a rectifying dowel portion 842E that bulges toward the water connection flange 841E1 of the first cooler top plate portion 841B by embossing or the like. This rectifying dowel part 842E prevents stagnation due to volume expansion and prevents unstable boiling when the pure water 181 flowing through the pure water flow path 845 does not evaporate and flows into the cooler dome part 841E in the liquid phase. The shape to be prevented, that is, the volume in the cooler dome portion 841E is not increased.
Furthermore, the second cooler top plate portion 842B projects upward in a cylindrical shape corresponding to the gas connection flange 841F, and is fitted and inserted into the gas connection flange 841F and the exhaust gas pipe 730 is fitted and inserted. An exhaust gas pipe connection portion 842F is provided.
Further, a support member 842G is provided on the inner peripheral surface on the lower end side of the second cooler cylindrical portion 842A. As shown in FIGS. 12, 13, 16, and 17, this support member 842G is formed in a C-shape in plan view, and is attached to the lower end side inner peripheral surface of the second cooler cylindrical portion 842A. 842G1 and a support tongue piece 842G2 that protrudes inwardly at the position of the upper end edge of the ring mounting portion 842G1 in the circumferential direction and that supports the third cooler member 843. is doing. In FIG. 17, the second cooler member 842 is omitted for convenience of explanation.

The third cooler member 843 has an inverted U-shaped cross-section that opens at the lower end serving as one end in the axial direction, and has a cylindrical third cooler cylindrical portion 843A and the other end side in the axial direction of the third cooler cylindrical portion 843A. And a third cooler top plate portion 843B that is provided in series at the upper end and closes the upper end surface of the third cooler cylindrical portion 843A, and is formed in a cylindrical shape.
In addition, a cooler stopper 843C that is bent upward is provided substantially at the center of the upper surface of the third cooler top plate portion 843B. The cooler stopper 843C is in contact with the lower surface of the second cooler top plate portion 842B, so that a predetermined gap is secured between the cooler stopper 843C and the second cooler top plate portion 842B.
Further, since the first cooler member 841, the second cooler member 842, and the third cooler member 843 are formed in a substantially cup shape, they can be easily manufactured by press molding, can be easily assembled, and the manufacturing cost can be reduced. Furthermore, since the first cooler dowel portion 841D and the second cooler dowel portion 842D also have a shape protruding toward the inner peripheral side, dowel processing can be easily performed.

  As shown in FIGS. 11 and 13 to 15, the exhaust gas cooler 840 has a closed connection projecting in a bowl shape from the peripheral portion of the first cooler top plate portion 841 </ b> B of the first cooler member 841 toward the outer peripheral direction. A plate 848 is provided. The closing connection plate 848 is joined with its outer peripheral edge overlapped with the inner peripheral side end plate 806 of the CO selective oxidizer 830, and the exhaust gas cooler 840 and the CO selective oxidizer 830 are integrally connected. The CO removing unit 800 and the piping unit 700 are partitioned by the closed connecting plate 848, the inner peripheral side end plate 806 of the CO selective oxidizer 830, and the outer peripheral side end plate 805 of the CO transformer 810. The inside communicates with the inside of the pedestal case 860 through the heat treatment means 820. In the state where the third cooler member 843 is placed and supported on the support member 842G, the lower end side of the exhaust gas discharge passage 847 is opened and communicates with the pedestal case 860. As a result, the combustion gas of the burner unit 151 flowing into the exhaust gas discharge passage 847 from the pedestal case 860 is sufficiently cooled by heat exchange with the pure water 181 flowing through the pure water passage 845 located on the outer peripheral side, and the exhaust gas It is exhausted from the pipe 730 as exhaust gas.

[Operation of fuel cell system]
Next, the operation in the fuel cell system 100 described above will be described. In the present embodiment, a configuration in which a fuel cell stack 200 generates power using a gaseous raw fuel such as natural gas as a main raw material is illustrated.

(Start-up (power generation) operation)
First, when the control device acquires a signal related to a power generation request, raw fuel and air are supplied to the burner unit 151 to heat the reformer 620. Before starting, gaseous raw fuel is sealed in the reformer 620, the CO converter 810, and the CO selective oxidizer 830.
The combustion gas from the burner unit 151 heats the combustion cylinder 621A of the combustion chamber 621, and spirally modifies the combustion cylinder 621A and the inner peripheral side of the protective cover 623 upward from the lower end of the combustion cylinder 621A. The protective cover 623 is heated through the upper part of the quality container 622. Further, the combustion gas flows downward between the outer peripheral surface of the reforming vessel 622 and the inner peripheral surface of the reforming outer case 610. In this way, the reforming vessel 622 is heated by the radiant heat and combustion gas from the heated combustion chamber portion 621 and combustion cylinder portion 621A. In this heating of the reforming vessel 622, since the combustion gas does not directly contact the reforming vessel 622, the temperature variation due to the combustion gas flow hardly occurs, and the reforming vessel 622 is stably heated. The protective bottom 623B of the protective cover 623 facing the burner unit 151 and easily overheats is provided with a heat insulating member 624 to prevent abnormal overheating of the raw material gas flowing into the reformer 620.
The combustion gas of the burner unit 151 flows below the reforming vessel 622, heats the outer peripheral surface of the gas heat exchange unit 640, and flows into the exhaust air duct outer tube 652 of the boiler 650, into the piping unit 700. Flows in. The combustion gas flowing into the piping unit 700 flows through the heat treatment means 820 of the CO removing unit 800 and flows into the base case 860. When the combustion gas flows through the heat treatment means 820, the CO converter 810 located on the outer peripheral side and the CO selective oxidizer 830 located on the inner peripheral side are heated. Since the entire amount of combustion gas flows through the heat treatment means 820, the CO converter 810 and the CO selective oxidizer 830 can be heated relatively quickly without using an electric heater or the like.
Further, the combustion gas of the burner unit 151 that has flowed into the base case 860 flows through the exhaust gas discharge passage 847 of the exhaust gas cooler 840 and is exhausted as exhaust gas from the exhaust gas pipe 730. Even if soot or condensation occurs during circulation through the exhaust gas discharge channel 847, the exhaust gas discharge channel 847 is a 1 mm gap, so water droplets that have soot or condensed fall down and are long. Even if the operation is performed for a period, the exhaust gas discharge passage 847 is not blocked.

When the reforming vessel 622 reaches a predetermined temperature, that is, from the temperature at which the raw fuel starts to coke on the reforming catalyst determined according to the type of reforming catalyst and the type of raw fuel (for example, 400 ° C.). Pure water stored in the pure water tank 180 by driving the transport pump 182 when it is estimated that the temperature is lower and higher than the condensing temperature of water vapor (for example, 350 ° C., which is a control temperature for starting water supply). 181 is supplied from the water supply path 183 to the reforming unit 400.
That is, gaseous raw fuel is enclosed in the reforming vessel 622, and if it reaches 400 ° C. or higher, coking may occur. For this reason, it is necessary to purge the gaseous raw fuel with steam before coking occurs.

Due to the processing of this control device, the supplied pure water 181 flows into the pure water retention portion 846 of the exhaust gas cooler 840 of the heat exchange device 160, and the pure water flow path is relatively smooth due to the curved curved surface of the cooler step portion 841C. It flows into 845 and flows into the CO selective oxidation cooling pipe 852. During this circulation, the combustion gas is heated while being cooled by heat exchange with the combustion gas of the burner unit 151 that circulates in the exhaust gas exhaust passage 847 of the exhaust gas cooler 840 from within the base case 860.
The pure water 181 flowing into the CO selective oxidation cooling pipe 852 is further heated by the CO selective oxidizer 830 heated by the heat treatment means 820 and flows into the CO shift cooling cooling pipe 851. Further, the pure water 181 that has flowed into the CO shift cooling pipe 851 is further heated by the CO shift converter 810 that is heated by the heat treatment means 820. In addition, the heat treatment means 820 is circulated before the CO conversion cooling pipe 851 flows into the reformed water inner pipe 651 of the boiler 650, and further heat exchange is performed with the combustion gas of the burner unit 151 that circulates through the heat treatment means 820.

The pure water 181 flowing into the reformed water inner pipe 651 of the boiler 650 is heated while cooling the combustion gas by heat exchange with the combustion gas of the burner unit 151 flowing through the exhaust air duct outer pipe 652 of the boiler 650 described above. And become superheated steam.
Then, the steam generated in the boiler 650 flows into the source gas inflow space 642E1 of the gas heat exchange unit 640 via the steam mixer 140, and the source gas inflow chamber 622H1 of the reforming vessel 622 from the source gas flow path 642E2. Then, the gas sequentially flows into the reforming chamber 622H2 and the reformed gas channel 622H3. Further, the steam flowing through the reformed gas flow path 622H3 of the reforming vessel 622 flows through the reformed gas flow passage 642E3 of the gas heat exchange unit 640 and is supplied to the CO converter 810 via the reformed gas outflow pipe 642F. Is done. The water vapor supplied to the CO converter 810 sequentially flows through the gas diffusion region 812, the CO conversion reaction region 813, and the gas converging region 814, and is supplied to the CO selective oxidizer 830 through the connecting pipe 740. The water vapor supplied to the CO selective oxidizer 830 sequentially flows through the diffusion region 832, the CO selective oxidation reaction region 833, and the convergence region 834, and passes through the fuel gas pipe 760 to the outside of the reforming unit 400, that is, to the fuel cell stack 200. Inflow. In this way, the source gas is purged with water vapor and coking is prevented.
When the amount of water supplied reaches a predetermined amount, that is, when the water vapor generated by the water supply reaches a sufficient amount (for example, 5 mL) to purge the reformer 622, the water supply is temporarily stopped. At this time, if the CO transformer 810 is below the condensation temperature of the steam, the steam is condensed in the pipe 642F and stored in the inflow chamber 812 below the CO transformer 810, and the CO transformer 810 is not wetted. Note that the supply of water does not have to be stopped if it can be confirmed by a temperature sensor or the like that the CO converter 810 is at or above the condensation temperature of water vapor before the supply of water is stopped.

In addition, the control device performs a process of supplying pure water 181 to the reforming unit 400 and a process of supplying the raw fuel stored in the raw fuel storage means 10 to the raw fuel supply means 110. The raw fuel is desulfurized by the desulfurizer 310 of the desulfurization apparatus 300.
When the control device detects that the temperatures of the reforming chamber 622H2, the CO converter 810, and the CO selective oxidizer 830 of the reforming vessel 622 have reached predetermined temperatures, the control unit converts the raw fuel after the desulfurization treatment into the raw fuel. Supply from the supply means 110 to the reforming unit 400. Further, the control device causes air to be supplied to the communication pipe 740 from the air introduction pipe 750 provided in the CO transformer 810.
The raw fuel supplied from the raw fuel supply means 110 flows into the steam mixer 140 from the raw fuel pipe 720, is mixed with the steam supplied from the boiler 650, and passes through the raw material gas supply pipe 642D to provide the gas heat exchange unit 640. Into the raw material gas inflow space 642E1 and into the raw material gas inflow chamber 622H1 of the reforming vessel 622 through the raw material gas flow path 642E2. The raw material gas is then steam reformed from the raw material gas inflow chamber 622H1 through the reforming chamber 622H2, and is passed through the reformed gas channel 622H3 as the reformed gas, and the reformed gas flow passage of the gas heat exchange unit 640 642E3 is distributed. When flowing through the reformed gas flow passage 642E3, the raw material gas is heated by exchanging heat with the raw material gas mixed with the water vapor flowing through the raw material gas channel 642E2. Then, the reformed gas flowing through the reformed gas flow passage 642E3 of the gas heat exchange unit 640 is supplied to the CO converter 810 via the reformed gas outflow pipe 642F.

Here, the heat exchanging device 160 heats the pure water 181 from the exhaust gas cooler 840 through the CO selective oxidation cooling pipe 852 and the CO shift cooling cooling pipe 851 of the CO removal heat exchanging section 850 in order, and then generates steam in the boiler 650. It is generated.
For this reason, superheated steam is generated at the outlet of the boiler 650, and in the reforming vessel 622, a raw material gas mixed with raw fuel and steam is brought into a favorable reforming process.

The reformed gas that has flowed into the CO converter 810 flows into the gas diffusion region 812 of the CO converter 810, flows through the CO shift reaction region 813, and CO in the reformed gas is converted. The reformed gas in which CO is transformed is mixed with the air supplied from the air introduction pipe 750 from the gas convergence area 814 via the connecting pipe 740 and flows into the diffusion area 832 of the CO selective oxidizer 830. The CO in the reformed gas is oxidized to carbon dioxide (CO ₂ ) through the CO selective oxidation reaction region 833, the CO in the reformed gas is removed, and the fuel cell stack is fed from the fuel gas pipe 760 as fuel gas. Supplied to 200.
Here, when the CO in the reformed gas is converted by the CO converter 810 and when the CO is selectively oxidized by the CO selective oxidizer 830, an exothermic reaction occurs. Become. The heat generated during CO transformation is exchanged with the combustion gas flowing through the heat treatment means 820 while suppressing heat transfer to the CO selective oxidizer 830 by the radiation prevention plate of the heat treatment means 820, thereby preventing overheating. Is done.
The fuel gas supplied to the fuel cell stack 200 is supplied to the negative electrode 202 side of the fuel cell stack 200. When the fuel gas flows into the fuel cell stack 200, it may be appropriately humidified with a humidifier, for example, if necessary. The hydrogen of the fuel gas supplied to the negative electrode 202 side is appropriately humidified as necessary, and reacts with oxygen in the air supplied to the positive electrode 201 side of the fuel cell stack 200 to generate water. DC power is generated between the negative electrode 202 and the negative electrode 202.
The fuel gas containing surplus hydrogen on the negative electrode 202 side is supplied to, for example, the burner unit 151 and burned.

(Stop operation)
Further, when the operation is stopped, the control device stops the supply of the raw fuel, continues the supply of the pure water 181 and stops the combustion of the burner unit 151. Water vapor is circulated and purged by the supplied pure water 181 in the same manner as the above-described water vapor purge at the time of startup. Each part is rapidly cooled by the circulation of the water vapor.
Then, the supply of pure water 181 is stopped before reaching a temperature at which water vapor is condensed. Thereafter, before the purged water vapor is condensed and the internal pressure falls below the external air pressure, the raw fuel after the desulfurization treatment is supplied again, the water vapor is purged with the raw fuel, and the operation is stopped.

(Emergency stop operation)
On the other hand, for example, when the control device cannot be controlled due to an electric power trouble and the emergency stop is performed, the supply of the raw material gas is automatically shut off by the electromagnetic valve or the like, and the supply of the pure water 181 is also stopped. . Then, the combustion of the burner unit 151 is also stopped.
In this state, the flow of the pure water 181 in the path of the heat exchange device 160, in particular, the pure water retention portion 846 and the pure water 181 in the pure water flow path 845, which are in a liquid state, is stopped. For this reason, the pure water 181 immediately becomes water vapor due to the surrounding residual heat. Since the generated water vapor is extremely larger than the liquid phase pure water 181 having the same mass, the raw material gas remaining in the entire flow path is purged with the water vapor and coking is prevented. In addition, it is good to provide the structure finally filled with raw fuel, an inert gas, etc. so that the inside of a flow path may not become negative pressure from atmospheric pressure by condensation of water vapor | steam.

[Effects of fuel cell system]
As described above, in the embodiment described above, the gas diffusion region 812 into which the reformed gas flows is provided inside the CO converter 810, and the CO conversion reaction region 813 communicated with the gas diffusion region 812 is provided. When the reforming catalyst reaches a predetermined temperature when the temperature of 620 is raised, water for generating steam for purging the gaseous raw fuel filled in the reformer 620 is supplied and flows into the gas diffusion region 812. The water supply is stopped before the water vapor condenses and overflows and flows into the CO shift reaction region 813.
For this reason, even when the raw fuel remains in the reformer 620, steam is generated by the supplied water and purged, so that the reforming catalyst can be prevented from being deteriorated by coking. Furthermore, even if the CO converter 810 is not sufficiently heated and the water vapor is condensed, the CO converter 810 and the CO selective oxidizer 830 get wet because the catalyst once flows into the gas diffusion region 812 and condenses. Deterioration can be prevented, and stable treatment can be provided for a long time. Further, even if the CO converter 810 is not heated by an electric heater or the like, a simple gas diffusion region 812 is provided for storing condensed water, that is, storing water upstream of the CO conversion reaction region 813. The structure can prevent the catalyst from deteriorating and can further improve the energy efficiency.
Further, the gas diffusion region 812 is used as a region for storing water by condensation, that is, a space for diffusing the inflowing reformed gas is used to distribute the reformed gas uniformly to the CO shift reaction region 813. For this reason, the structure for storing separately condensed water is unnecessary, and the stored water circulates again as water vapor at a further increase in temperature, so that it does not accumulate and is heated to a temperature that does not condense. The volume of the condensed water can be stored in the order of several ml, and the apparatus can be easily simplified and downsized.
In the present embodiment, a diffusion region 832 into which the reformed gas flows also inside the CO selective oxidizer 830 and a CO selective oxidation reaction region 833 communicating with the diffusion region 832 are provided. For this reason, even if the reformed gas flows without being condensed in the CO converter 810 and is condensed when it flows into the CO selective oxidizer 830, the catalyst remains in the same manner as in the CO converter 810 described above. It can be prevented from getting wet and deteriorated, and further stable operation for a long period can be provided.

The supply of water when the reformer 620 is heated starts when the temperature of the CO converter 810 and the CO selective oxidizer 830 is raised to a temperature higher than the water condensation temperature.
For this reason, steam purging for preventing coking can be carried out without providing a special configuration without condensing in the downstream flow path from the steam mixer 140, and catalyst deterioration can be prevented with a simple structure, which is long. Can provide stable operation for a period. In addition, since the condensation can be prevented, the gas diffusion region 812 and the diffusion region 832 may be designed so that the reformed gas that has flowed in can be diffused satisfactorily. I can plan.

In addition, the CO transformer 810, the heat treatment means 820, and the CO selective oxidizer 830 have a multilayer structure in which they are stacked in the radial direction.
For this reason, even at the beginning of startup, the CO converter 810 and the CO selective oxidizer 830 can be easily heated by the heat treatment means 820, the time for condensing steam can be shortened, and the CO conversion catalyst and C0 can be prevented while preventing coking of the reforming catalyst. Control for preventing the selective oxidation catalyst from getting wet due to condensation can be facilitated. In addition, since the condensation time is short, even if condensed water is stored in the gas diffusion region 812, the amount of stored water is very small, and the volume of the gas diffusion region 812 for storing water is increased. There is no need to form the device, and an increase in size of the apparatus can be prevented. The CO selective oxidizer 830 does not need to increase the volume of the diffusion region 832 and has the same effect as that of the CO converter 810.
Further, since the heat treatment means 820 has a configuration in which the combustion gas of the burner unit 151 circulates, it is not necessary to heat the CO converter 810 and the CO selective oxidizer 830 with an electric heater or the like. Further improvement is obtained.

Since the heat treatment means 820 has a configuration in which the combustion gas of the burner unit 151 is circulated, an excessive temperature of the CO converter 810 due to heat transfer from the CO converter 810 to the CO selective oxidizer 830 during normal operation. Inconveniences such as reduction and overheating of the CO selective oxidizer 830 can also be suppressed.
For this reason, favorable heat exchange is obtained and further improvement in energy efficiency is obtained.

Further, as a multilayer structure of the CO converter 810, the heat treatment means 820, and the CO selective oxidizer 830, a first CO removal member 801, a second CO removal member 802, a third CO removal member 803, and a fourth CO removal member 804 are provided. It has a quadruple tube structure.
For this reason, it can be constructed as an integrated structure CO removing unit 800 with a simple configuration, and the structure can be simplified and the productivity can be easily improved. That is, with a multilayer structure, it can be constructed as a quadruple tube structure, and simplification of the structure and improvement of manufacturability can be easily achieved.

Further, as the heat exchange device 160, the pure water 181 is heated through the exhaust gas cooler 840, the CO selective oxidation cooling pipe 852 and the CO shift cooling pipe 851 of the CO removal heat exchange unit 850 in order to generate water vapor. .
For this reason, since the water vapor mixed with the gaseous raw fuel is superheated steam, the gaseous raw fuel and the water vapor are mixed in the reforming vessel 622, and a good reforming process is obtained.

The fuel cell system 100 generates power by the fuel cell stack 200 using the fuel gas obtained by the reforming unit 400 that can prevent catalyst deterioration even in an emergency stop.
For this reason, since it can process stably for a long period of time, it can improve the process efficiency which produces | generates fuel gas and generates electric power, and can also perform maintenance management easily.

[Modification]
The aspect described above shows one aspect of the present invention, and the present invention is not limited to each of the above-described embodiments, and within the scope of achieving the objects and effects of the present invention. Needless to say, variations and improvements are included in the content of the present invention. In addition, the specific structure and shape in carrying out the present invention may be used as other structures and shapes within the scope of achieving the object and effect of the present invention.

That is, as described above, the reforming unit 400 of the present invention has been described as being used in the fuel cell system 100, but may be applied as, for example, a hydrogen gas production apparatus used in the fuel cell system 100. .
Further, as described above, the unit configuration is not limited to a configuration in which all of the steam mixer 140, the heat exchange device 160, the reformer 620, the CO converter 810, and the CO selective oxidizer 830 are incorporated. For example, the CO removing unit 800 may have a unit configuration in which the respective components are appropriately combined, such as a separate unit from the reforming unit 600 or a separate configuration of the CO converter 810 and the CO selective oxidizer 830. In addition, it is effective in terms of thermal efficiency that the above-described reforming unit 400 is integrated.
Further, although the CO converter 810 and the CO selective oxidizer 830 are configured in a coaxial multilayer structure, they may be configured in the vertical direction. In addition, it is effective in the point of size reduction by comprising in the coaxial multilayered structure mentioned above.
In addition, although the CO selective oxidizer 830 has been described, for example, instead of the CO selective oxidizer 830, a methanation device that methanates CO remaining in the reformed gas may be provided. In this case, the methanation device may be provided with the inflow chamber and the catalyst filling chamber of the present invention.

  When steam purging is performed when the temperature of the reformer 620 at the time of startup is increased, for example, a water level sensor is provided in the gas diffusion region 812, and before the condensed water reaches the CO shift reaction region 813 or the CO selective oxidation reaction region 833. Until the gas diffusion region 812 is heated to a temperature that is higher than the condensation temperature of the water and stops condensing. Depending on whether the amount of water reaches the volume of the gas diffusion region 812, the supply or interruption of water may be controlled. The same applies to the CO selective oxidizer 830.

In addition, the heat exchange device 160 is configured by the boiler 650 and the exhaust gas cooler 840, but is not limited to this configuration, and any one or a combination thereof may be used.
Further, the gas heat exchange unit 640 may not be provided.

In addition, although the configuration in which the raw fuel is supplied and filled in the state where the water vapor is condensed and becomes a negative pressure from the atmospheric pressure after the water vapor is purged, the negative pressure is maintained using, for example, an electromagnetic valve. It may be.
Further, various negative pressure countermeasures such as storing fuel gas separately during operation and supplying the fuel gas when negative pressure may be implemented as a countermeasure against negative pressure.

As the CO converter 810 and the CO selective oxidizer 830, a CO conversion partition plate 811 and a CO selective oxidation partition plate 831 are provided, and spaces are formed above and below the CO conversion reaction region 813 and the CO selective oxidation reaction region 833. For example, without providing the CO conversion partition plate 811 and the CO selective oxidation partition plate 831, various inorganic oxide spheres that are ceramics that are stable to heat, moisture, and reformed gas, such as alumina, silica, and mullite in the space portion, The reformed gas may be diffused and converged by filling granular materials or the like.
In such a case, it is preferable that the water droplets condensed by the water vapor purge are designed to have a void corresponding to a volume that does not adhere to the catalyst. Further, although the gas diffusion region 812 and the diffusion region 832 are defined as the CO converter 810 and the CO selective oxidizer 830, the inflow chamber of the present invention includes a CO conversion reaction region 813 and a CO selective oxidation reaction region such as a drain, for example. The catalyst in the 833 may be configured not to get wet with condensed water.

  In addition, the specific structure and shape in the implementation of the present invention may be other structures as long as the object of the present invention can be achieved.

  The present invention uses a raw material gas containing a hydrocarbon fuel and mixed with water vapor, such as a liquid fuel such as kerosene or a gaseous fuel such as liquefied petroleum gas, and is brought into contact with a reforming catalyst heated by a heating means to generate hydrogen gas. It can utilize for the steam reforming process which produces | generates the reformed gas containing this. In particular, it can be used for the production of hydrogen gas used for power generation of a fuel cell of a fuel cell system.

100 ... Fuel cell system
151 ... Burner unit as a combustor
160 ... a heat exchanger as a heat exchanger
200 ... Fuel cell stack
400 ... reforming unit as reformed gas production equipment
600 ... Reformer as reformer
620 ... reformer
810 ... CO transformer
811 ... CO metamorphic division board
812 ... Gas diffusion region as inflow chamber
813 ... CO shift reaction zone as catalyst filling chamber
820 ... Heat treatment means
830 ... CO selective oxidizer
831 ... CO selective oxidation partition plate
832… Diffusion area as inflow chamber
833 ... CO selective oxidation reaction region as a catalyst filling chamber
840 ... Exhaust gas cooler as heat exchanger

Claims (6)

A reformer that produces a reformed gas mainly composed of hydrogen gas by bringing a raw material gas containing hydrocarbon fuel and steam into contact with the reforming catalyst in a heated atmosphere to perform a steam reforming process, and the reformer. The reformed gas is supplied to convert carbon monoxide (CO) in the reformed gas into carbon dioxide (CO ₂ ) by a CO shift catalyst, and the reformer treated by the CO shift converter Operation control of a reformed gas production apparatus provided with a CO selective oxidizer that supplies gas and oxidizes CO remaining in the reformed gas to CO ₂ by a CO selective oxidation catalyst or a methanation device that methanates CO A method,
As the CO converter, an apparatus including an inflow chamber into which the reformed gas flows and a catalyst filling chamber that is connected to the inflow chamber and is filled with a catalyst is used.
When the reforming catalyst reaches a predetermined temperature at the time of raising the temperature of the reformer, supplying water for generating the steam that can purge the gaseous hydrocarbon fuel filled in the reformer,
An operation control method for a reformed gas production apparatus, wherein the water supply is stopped before the water vapor flowing into the inflow chamber condenses and overflows and flows into the catalyst filling chamber. An operation control method for the reformed gas production apparatus according to claim 1,
When the generation of the reformed gas is interrupted, the reformer, the CO converter and the CO selective oxidizer or the steam is generated by stopping the supply of the hydrocarbon fuel and supplying only the water. When the inside of the reformer, the CO converter and the CO selective oxidizer or the methanator is reduced from the atmospheric pressure after the inside of the methanator is purged, the gas is condensed. A method for controlling the operation of a reformed gas production apparatus, characterized in that a hydrocarbon fuel is supplied. A reformer that produces a reformed gas mainly composed of hydrogen gas by bringing a raw material gas containing hydrocarbon fuel and steam into contact with the reforming catalyst in a heated atmosphere to perform a steam reforming process, and the reformer. The reformed gas is supplied to convert carbon monoxide (CO) in the reformed gas into carbon dioxide (CO ₂ ) by a CO shift catalyst, and the reformer treated by the CO shift converter A reformed gas production comprising: a CO selective oxidizer that oxidizes CO remaining in the reformed gas to CO ₂ by a CO selective oxidation catalyst or a methanation device that methanates CO and a control device A device,
The CO converter includes an inflow chamber into which the reformed gas flows, and a catalyst filling chamber in communication with the inflow chamber and filled with a catalyst.
The controller is configured to generate water vapor that can purge the gaseous hydrocarbon fuel filled in the reformer when the reforming catalyst reaches a predetermined temperature when the reformer is heated. And the supply of water is controlled before the water vapor flowing into the inflow chamber condenses and overflows and flows into the catalyst filling chamber. The reformed gas manufacturing apparatus according to claim 3,
The inflow chamber and the catalyst charging chamber are defined by a partition plate having a plurality of holes through which the reformed gas can flow, and the catalyst charging chamber is positioned above the inflow chamber in the vertical direction. A reformed gas production apparatus characterized by being provided in a state where The reformed gas production apparatus according to claim 3 or 4, wherein
The reformer includes a combustor that heats the reforming catalyst by burning at least one of the hydrocarbon fuel, the raw material gas, or the reformed gas,
The CO converter is laminated in a radial direction, and is formed in a multilayer structure in which the combustion gas of the combustor flows between the CO converter and the CO selective oxidizer or the methanation device. Reformed gas production equipment. The reformed gas production apparatus according to any one of claims 3 to 5,
An oxygen-containing gas supply means for supplying an oxygen-containing gas;
A fuel cell system comprising: a fuel cell that generates electric power using the reformed gas generated by the reformed gas production apparatus and the oxygen-containing gas supplied by the oxygen-containing gas supply means. .

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