JP7320701B2 - Hydrogen generator and fuel cell system - Google Patents

Description

The present disclosure relates to hydrogen generators and fuel cell systems.

Patent Literature 1 discloses a hydrogen generator capable of preventing condensed water from reaching a heating means even when water vapor contained in off-gas is condensed.

This hydrogen generator has a reforming section that generates a hydrogen-rich reformed gas by a steam reforming reaction from a hydrocarbon fuel and water, and burns off-gas returned from a fuel cell to which the reformed gas is supplied. a heating means for heating the reforming section by heating; a fuel gas supply pipe for supplying off-gas to the heating means; a combustion air supply pipe for supplying combustion air to the heating means; , and a water receiver for storing condensed water contained in the off-gas.

Further, Patent Literature 2 discloses a fuel cell system having a water treatment device capable of removing sulfur components.

This fuel cell system consists of a fuel cell that generates electricity by reacting a fuel gas containing hydrogen with an oxidant gas, and a condensed water tank that stores water obtained by condensing water vapor contained in the exhaust gas discharged from the fuel cell. , a water treatment device for purifying water in a condensed water tank, and a fuel treatment device for generating fuel gas by a reforming reaction using raw materials and water purified by the water treatment device.

JP 2008-159373 A JP 2014-135126 A

The present disclosure provides a hydrogen generator that suppresses submersion of the catalyst and reduces deterioration of the catalyst when reforming water is erroneously introduced.

The hydrogen generator according to the present disclosure includes a reforming unit that reacts a raw material and steam to generate a reformed gas containing hydrogen, and a carbon monoxide reduction unit that reduces the concentration of carbon monoxide contained in the reformed gas. a water evaporator that generates steam from the supplied reformed water, mixes the generated steam with the raw material, and supplies the mixture to the reformer; and a reformed water supply port that supplies the reformed water to the water evaporator. , a reforming section, a carbon monoxide reducing section, and a heating section for heating the water evaporating section.

A space for storing reforming water that has accidentally flowed in is formed at a position lower than the lowermost portions of the reforming section and the carbon monoxide reducing section in the portion where the reforming section and the carbon monoxide reducing section communicate with each other. .

In the hydrogen generator according to the present disclosure, when reforming water is mistakenly introduced, a position lower than the lowest part of the reforming section and the carbon monoxide reduction section in the portion that communicates between the reforming section and the carbon monoxide reduction section Reforming water can be stored in the space formed in . Therefore, it is possible to prevent the reforming section and the carbon monoxide reducing section from being submerged in water, and reduce deterioration of the catalysts of the reforming section and the carbon monoxide reducing section.

Schematic diagram of the hydrogen generator in Embodiment 1 Schematic diagram of the fuel cell system in Embodiment 1

(Knowledge, etc. on which this disclosure is based)
At the time when the inventors came up with the present disclosure, there was a technology in which a hydrogen generator supplies reforming water to the hydrogen generator to cause a reforming reaction when the temperature of the reforming section rises to a predetermined temperature.

However, due to a malfunction of the reforming water supply unit (malfunction of the supply unit, failure of the on-off valve provided in the supply unit), the reforming water may be supplied to the hydrogen generator when the reforming unit is at a predetermined temperature or lower. .

In this case, the inventors found a problem that the catalyst in the reforming section is submerged and the catalyst performance is deteriorated, such as frequent cracking of the catalyst due to low catalyst strength. have come to form the subject matter of this disclosure.

Therefore, the present disclosure is a hydrogen generator that prevents the reforming section and the carbon monoxide reduction section from being submerged by accumulating the reformed water that has accidentally flowed into the portion that communicates the reforming section and the carbon monoxide reduction section. I will provide a.

Hereinafter, embodiments will be described in detail with reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially the same configurations may be omitted. This is to avoid the following description from becoming more redundant than necessary and to facilitate understanding by those skilled in the art.

It should be noted that the accompanying drawings and the following description are provided for a thorough understanding of the present disclosure by those skilled in the art and are not intended to limit the claimed subject matter.

(Embodiment 1)
Embodiment 1 will be described below with reference to FIGS. 1 and 2. FIG.

[1-1. composition]
[1-1-1. Configuration of hydrogen generator]
First, the hydrogen generator 101 provided in the fuel cell system 200 will be described with reference to FIG.

The hydrogen generator 101 is provided with a cylindrical combustion cylinder 130 below a heating section 102 that burns fuel. A bottomed cylindrical inner cylinder 105 having an inner cylinder bottom plate 106 is arranged outside the combustion cylinder 130 . A bottomed cylindrical middle cylinder 107 having a middle cylinder bottom plate 108 is arranged outside the inner cylinder 105 . A bottomed cylindrical outer cylinder 115 having an outer cylinder bottom plate 116 is arranged outside the middle cylinder 107 .

The combustion cylinder 130, the inner cylinder 105, the middle cylinder 107, and the outer cylinder 115 are arranged so as to have substantially concentric circular shapes (including concentric circular shapes) when viewed from above (top view). The upper portions of the inner cylinder 105, middle cylinder 107, and outer cylinder 115 are appropriately connected to form a substantially cylindrical (including cylindrical) reactor.

A through hole 109 is formed in the central portion of the bottom plate 108 of the middle cylinder. The middle cylinder 107 uses the space with the inner cylinder 105 and the space with the outer cylinder 115 to turn the gas in the opposite direction (from the bottom to the top in FIG. 1) halfway (through hole 109 in the bottom plate 108 of the middle cylinder). A flow path (first gas flow path) is formed.

In addition, on the outer wall surface of the hydrogen generator 101 on the opposite side (upper in FIG. 1) of the gas folding part side (lower in FIG. 1) in the hydrogen generator 101, it is connected to an external gas pipe, A raw material supply port 104 is provided to supply the raw material gas to the hydrogen generator 101 (specifically, the space between the inner cylinder 105 and the middle cylinder 107).

In addition, on the outer wall surface of the hydrogen generator 101 in the upper part of FIG. A reforming water supply port 103 for supplying reforming water is provided.

The raw material gas supplied from the raw material supply port 104 and the reforming water supplied from the reforming water supply port 103 flow between the inner cylinder 105 and the middle cylinder 107 toward the through hole 109 of the bottom plate 108 of the middle cylinder, It is heated in the water evaporator 123 and reformed in the reformer 120 to become a reformed gas.

The reformed gas reverses its flow direction at the through-hole 109, flows between the middle tube 107 and the outer tube 115 toward the lead-out portion 112, and passes through the shift conversion portion 125 and the selective oxidation portion 126. Carbon monoxide in the reformed gas is reduced. The transformation section 125 and the selective oxidation section 126 are carbon monoxide reduction sections.

A water evaporator 123 is provided in the space between the inner cylinder 105 and the middle cylinder 107 . In the water evaporating section 123, the heat transferred from the combustion exhaust gas of the heating section 102 passing between the combustion tube 130 and the inner tube 105 through the inner tube 105 is utilized to generate the reforming water supplied from the reforming water supply port 103. As the water evaporates, the mixed gas of the source gas and water vapor is preheated.

Further, in the reforming section 120 provided on the downstream side (below) of the water evaporation section 123 in the space between the inner cylinder 105 and the middle cylinder 107, the heating section 102 passing between the combustion cylinder 130 and the inner cylinder 105 Using the heat transferred from the combustion exhaust gas through the inner cylinder 105, the reforming catalyst causes the raw material gas and steam to undergo a reforming reaction to generate a reformed gas.

In the shift conversion section 125 provided in the space between the middle tube 107 and the outer tube 115, the carbon monoxide in the reformed gas produced in the reforming section 120 is converted into water vapor and the water gas shift reaction by the CO shift conversion catalyst. reduced to carbon dioxide.

The selective oxidation section 126 provided downstream (upper) of the shift conversion section 125 in the space between the middle tube 107 and the outer tube 115 remains in the hydrogen-containing gas after the water gas shift reaction in the shift conversion section 125. Carbon monoxide is converted to carbon dioxide by a selective oxidation catalyst using air supplied from the air supply port 119 to the hydrogen-containing gas after passing through the shift conversion section 125 .

The reforming section 120 is provided with a Ru-based reforming catalyst having a spherical shape with a diameter of about 3 mm.

Specifically, in the space formed by the side surfaces of the inner cylinder 105 and the middle cylinder 107, the side surface of the middle cylinder 107 is made of punching metal having a hole diameter of about 2 mm, which is smaller than the size of the reforming catalyst. A reforming catalyst is installed on the tray to be processed.

Further, the shift converter 125 is provided with a Cu—Zn-based CO shift conversion catalyst having a cylindrical shape with a diameter of about 3 mm and a height of 3 mm. Further, the selective oxidation unit 126 is provided with a Ru-based selective oxidation catalyst having a spherical shape with a diameter of about 3 mm.

The hydrogen generator 101 includes a heating section 102 inside an inner cylinder 105 for supplying reaction heat necessary for the reforming reaction in the reforming section 120 . The heating unit 102 includes a burner that burns combustion gas as a heating source, a combustion detection unit 122 that has a flame rod that detects the combustion state of the heating unit 102, and a combustion air that supplies combustion air to the heating unit 102. and a combustion fan 118 as a feeder.

The flame rod is a device that applies a voltage to ions generated when a flame is formed and measures the ion current value that flows at that time.

Combustion gas to be combusted in the heating section 102 is supplied to the heating section 102 through the anode off-gas path 16 . Also, the hydrogen-containing gas generated by the hydrogen generator 101 is supplied to the externally installed fuel cell 10 or the like via the lead-out portion 112 .

The reforming section 120 and the water evaporating section 123 are configured such that heat is supplied from the flue gas generated by the heating section 102 through the wall surface of the inner cylinder 105 facing the combustion cylinder 130 of the heating section 102. there is

The heating unit 102 combusts the anode off-gas discharged from the anode of the fuel cell 10 with a burner using combustion air to generate fuel exhaust gas containing reaction heat necessary for the steam reaction.

The combustion exhaust gas passes from the heating unit 102 through the interior (inner side) of the combustion tube 130, and after exiting the combustion tube 130, hits the lower part of the inner tube 105 and the inner tube bottom plate 106 in a high temperature state.

Then, the combustion exhaust gas passes through the passage formed by the outer peripheral surface of the combustion cylinder 130 and the inner peripheral surface of the inner cylinder 105, and passes through the reforming section 120, the shift conversion section 125, and the selective oxidation section 126. After being heated, it is exhausted to the outside of the hydrogen generator 101 from the upper right exhaust port in the drawing.

A heat insulating material 140 is arranged at a position of the bottom plate 106 of the inner cylinder facing the heating portion 102 so that the bottom plate 106 of the inner cylinder is not thermally deformed. The bottom plate 106 of the inner cylinder and the inner cylinder 105 are made of SUS310S material, which has a high proportion of nickel and is resistant to high-temperature thermal deformation.

In addition, in order to control the operation of the hydrogen generator 101, the hydrogen generator 101 includes a reforming temperature detection unit 121 for detecting the temperature of the reforming catalyst in the reforming unit 120 and a CO transformation catalyst in the transformation unit 125. A metamorphic temperature detection unit 124 for detecting the temperature of is provided.

A space 150 is provided at a position lower than the reforming section 120 on the exit side of the reforming section 120 . The reforming temperature detector 121 is arranged in the space 150 .

[1-1-2. Configuration of fuel cell system]
Next, a fuel cell system 200 equipped with the hydrogen generator 101 will be described with reference to FIG.

A fuel cell system 200 includes a hydrogen generator 101 and a fuel cell 10 . The fuel cell 10 uses the hydrogen-containing gas discharged from the hydrogen generator 101 to generate electricity. The fuel cell 10 is, for example, a polymer electrolyte fuel cell. Hot water is produced by exhaust heat of the fuel cell 10 . The generated hot water is stored in a hot water storage tank.

The fuel cell system 200 further includes a fuel gas supply path 12 , an oxidant gas supply path 14 , an anode offgas path 16 and a cathode offgas path 18 . The fuel gas supply path 12 is a path for supplying hydrogen-containing gas from the hydrogen generator 101 to the fuel cell 10 . The fuel gas supply path 12 connects the hydrogen generator 101 and the anode gas inlet of the fuel cell 10 .

The oxidizing gas supply path 14 is a flow path for supplying air as an oxidizing gas to the cathode of the fuel cell 10 . An air supplier 20 is provided in the oxidant gas supply path 14 .

The air supplier 20 is a blower that supplies air to the cathode of the fuel cell 10 . Other equipment such as a humidifier and a valve may be arranged in the oxidant gas supply path 14 .

The anode offgas path 16 is a path through which unreacted hydrogen-containing gas and unreacted raw material gas are discharged from the anode of the fuel cell 10 .

The anode offgas path 16 connects the anode gas outlet of the fuel cell 10 and the heating section 102 of the hydrogen generator 101 . The unreacted hydrogen-containing gas and unreacted raw material gas are supplied to the burner of the heating section 102 through the anode offgas path 16 .

The cathode offgas path 18 is a path through which unreacted oxidant gas is discharged from the cathode of the fuel cell 10 . The cathode offgas path 18 is connected to the cathode gas outlet of the fuel cell 10 and extends to the exterior of the housing of the fuel cell system 200, for example.

Fuel cell system 200 further comprises condensate tank 15 and clarifier 50 . The condensed water tank 15 is a tank that stores water used for operating the fuel cell 10 . In the present embodiment, condensed water tank 15 is a tank that stores water to be supplied to hydrogen generator 101 .

The purifier 50 is a member for purifying water in the condensed water tank 15 . The water in the condensed water tank 15 is supplied to the hydrogen generator 101 through the purifier 50 and used in the hydrogen generator 101 to generate hydrogen-containing gas. According to such a configuration, since purified water can be supplied to the hydrogen generator 101, it is possible to prevent scale from accumulating on the hydrogen generator 101. FIG.

Moreover, the fuel cell system 200 further includes a first water path 17 and a second water path 19 . The first water path 17 is a flow path extending from the condensed water tank 15 to the hydrogen generator 101 . The second water path 19 is a flow path that branches from the first water path 17 at a predetermined branch position BP and extends to the condensed water tank 15 .

The condensed water tank 15 is provided with a temperature sensor 21 (first temperature sensor). The temperature sensor 21 is arranged inside the condensed water tank 15 and detects the temperature of the water stored in the condensed water tank 15 . The temperature sensor 21 is, for example, a temperature sensor using a thermistor or a temperature sensor using a thermocouple.

Condensed water generated from the cathode off-gas, condensed water generated from the anode off-gas in the anode off-gas path 16, and condensed water generated from the combustion exhaust gas of the hydrogen generator 101 are collected and stored in the condensed water tank 15.

Excess water exceeding a predetermined water level in the condensed water tank 15 overflows from the condensed water tank 15 and is discharged outside the housing of the fuel cell system 200 through the drain path 67, for example.

The clarifier 50 is arranged inside the condensate tank 15 . Water (pure water) purified in the purifier 50 is supplied to the hydrogen generator 101 through the first water path 17 . The purifier 50 contains at least one selected from ion exchange resin, activated carbon, antibacterial material and permeable membrane.

Purifier 50 typically contains an ion exchange resin. Ion exchange resins are cation exchange resins, anion exchange resins, or both. The shape of the ion exchange resin may be particulate or fibrous. The fibrous ion exchange resin may be shaped into a thin film.

A pump 25 and a first on-off valve 27 are provided in the first water path 17 that supplies water to the hydrogen generator 101 . The pump 25 is positioned between the condensed water tank 15 and the branch position BP.

The pump 25 pumps up the water stored in the condensed water tank 15 through the clarifier 50 . The pump 25 serves to supply the water in the condensed water tank 15 to the hydrogen generator 101 . The first on-off valve 27 is positioned between the branch position BP and the hydrogen generator 101 . When the first on-off valve 27 is opened, the supply of water to the hydrogen generator 101 is permitted, and when the first on-off valve 27 is closed, the supply of water to the hydrogen generator 101 is prohibited.

The pump 25 is, for example, a positive displacement pump such as a piston pump, plunger pump, gear pump, or vane pump. The first on-off valve 27 is, for example, an electromagnetic valve. The second water path 19 has an upstream portion 191 , a downstream portion 193 and a purified water tank 195 .

The upstream portion 191 has one end connected to the branch position BP and the other end connected to the purified water tank 195 . Downstream portion 193 has one end connected to clarified water tank 195 and the other end connected to condensate tank 15 .

Water for cooling the fuel cell 10 is stored in the purified water tank 195 . When the water level in the purified water tank 195 exceeds a specified water level, water overflows from the purified water tank 195 and travels through the downstream portion 193 to the condensed water tank 15 .

A heater 29 is provided in the purified water tank 195 . The heater 29 is arranged inside the purified water tank 195 and heats the water stored in the purified water tank 195 as necessary.

The water temperature of the purified water tank 195 can be quickly raised by the heater 29 . The heater 29 is, for example, a resistance heating electric heater. In this embodiment, the purified water tank 195 is part of the second water path 19 . Therefore, heater 29 is provided in second water path 19 .

Purified water tank 195 is further provided with temperature sensor 23 . The temperature sensor 23 is arranged inside the purified water tank 195 and detects the temperature of the water stored in the purified water tank 195 . The temperature sensor 23 is also a temperature sensor using a thermistor or a temperature sensor using a thermocouple, for example.

The heater 29 is on/off controlled, for example, so that the water temperature of the purified water tank 195 falls within a predetermined temperature range. The "predetermined temperature range" is not particularly limited, and is determined according to the capacity of the fuel cell 10, the capacity of the purified water tank 195, and the like.

A second on-off valve 28 is provided in the second water path 19 . The second on-off valve 28 is provided in an upstream portion 191 of the second water path 19 and positioned between the branch position BP and the purified water tank 195 . The second on-off valve 28 is also an electromagnetic valve, for example.

In this embodiment, the condensed water tank 15, part of the first water path 17 and the second water path 19 form a circulation circuit. When the first on-off valve 27 is closed, the second on-off valve 28 is opened, and the pump 25 is operated, the water in the condensed water tank 15 circulates through the circulation circuit.

When the first on-off valve 27 is opened, the second on-off valve 28 is closed, and the pump 25 is operated, the water in the condensed water tank 15 is supplied to the hydrogen generator 101 .

In this embodiment, the first on-off valve 27 and the second on-off valve 28 constitute a channel switching device.

Fuel cell system 200 further comprises a condensate path 24 . The condensed water path 24 is branched from the cathode offgas path 18 and connected to the condensed water tank 15 . In this embodiment, the condensed water path 24 is connected to the condensed water tank 15 via the downstream portion 193 of the second water path 19 .

Condensed water generated from the cathode off-gas is led to the condensed water tank 15 through the condensed water path 24 and the downstream portion 193 of the second water path 19 . The condensed water path 24 may be directly connected to the condensed water tank 15 .

According to such a configuration, water can be continuously supplied to the hydrogen generator 101 without replenishing water from the outside. Since the condensed water discharged from the fuel cell 10 contains few impurities, the life of the purifier 50 is also extended.

The fuel cell system 200 further includes a cooling water circuit 31 , a heat exchanger 33 and a heat recovery water channel 35 . The cooling water circuit 31 is a channel for circulating water between the purified water tank 195 and the fuel cell 10 .

The cooling water circuit 31 can efficiently cool the fuel cell 10 and extract the waste heat of the fuel cell 10 to the outside of the fuel cell 10 in the form of hot water. The cooling water circuit 31 has a feed path 311 and a return path 312 . A feed path 311 and a return path 312 connect the fuel cell 10 and the purified water tank 195, respectively.

Water in the purified water tank 195 is supplied to the fuel cell 10 as cooling water through the feed path 311 . Water is then returned from the fuel cell 10 to the purified water tank 195 through the return path 312 .

A pump 37 is provided in the cooling water circuit 31 . In this embodiment, a pump 37 is arranged in the feed path 311 of the cooling water circuit 31 . A pump 37 may be arranged in the return path 312 . One of the positive displacement pumps previously described can be used as pump 37 .

A heat exchanger 33 is arranged in the cooling water circuit 31 . In this embodiment, the heat exchanger 33 is arranged in the feed path 311 of the cooling water circuit 31 . The heat exchanger 33 is, for example, a liquid-liquid heat exchanger such as a double tube heat exchanger or a plate heat exchanger.

The heat recovery channel 35 is a channel for recovering exhaust heat from the fuel cell 10 . The heat recovery channel 35 includes a feed channel 351 and a return channel 352 . The feed path 351 and return path 352 are each connected to the heat exchanger 33 . The feed path 351 constitutes an upstream portion of the heat recovery waterway 35 . The return path 352 constitutes the downstream portion of the heat recovery waterway 35 .

The return path 352 is a flow path that guides the water heated in the heat exchanger 33 to a hot water storage tank (not shown). The feed path 351 is a flow path that guides water to be heated in the heat exchanger 33 to the heat exchanger 33 .

The heat exchanger 33 is configured to exchange heat between the water flowing through the heat recovery water channel 35 and the water flowing through the cooling water circuit 31 . That is, the heat exchanger 33 serves to heat the water to be stored in the hot water storage tank (not shown) with the heat of the cooling water in the cooling water circuit 31 .

A pump 39 is provided in the heat recovery channel 35 . In this embodiment, a pump 39 is arranged in the feed path 351 of the heat recovery channel 35 . A pump 39 may be arranged in the return path 352 . One of the positive displacement pumps previously described can be used as pump 39 .

The fuel cell system 200 further includes a water supply path 36 and an on-off valve 38 . The on-off valve 38 is arranged in the water supply passage 36 . The water supply path 36 is a path for supplying water to the purified water tank 195 .

In this embodiment, the water supply channel 36 is branched from the heat recovery channel 35 and connected to the purified water tank 195 . Specifically, the water supply path 36 branches off from the feed path 351 of the heat recovery water path 35 between the pump 39 and the heat exchanger 33 . When the on-off valve 38 is opened to allow water to flow through the heat recovery water channel 35 , water is supplied to the purified water tank 195 through the water supply channel 36 .

When the on-off valve 38 is closed, the supply of water to the purified water tank 195 is cut off. The water supplied to the purified water tank 195 is, for example, city water. Water is supplied to the purified water tank 195 by the supply pressure of city water or the action of the pump 39 .

The fuel cell system 200 further includes a temperature sensor 45 (second temperature sensor) that detects the ambient temperature of the fuel cell system 200 . The temperature sensor 45 is arranged inside the housing of the fuel cell system 200, for example.

Depending on the ambient temperature detected by the temperature sensor 45, processing is performed to prevent freezing of water in each path. For example, when the ambient temperature detected by the temperature sensor 45 falls below a predetermined temperature while the fuel cell 10 is not generating power, the water is heated by the heater 29 and circulated in the circulation circuit.

Fuel cell system 200 further includes controller 41 . Detection signals from the temperature sensors 21 , 23 and 45 are input to the controller 41 . A detection signal is also input to the controller 41 from other measuring devices (not shown) such as a flow meter and a gas sensor.

The controller 41 controls objects to be controlled, such as the pump 25, the first on-off valve 27, the heater 29, the second on-off valve 28, and the pump 37, based on the measurement results of measuring devices such as temperature sensors, flow meters, and gas sensors. The controller 41 stores a program for properly operating the fuel cell system 200 .

In this embodiment, each channel is configured by at least one pipe. The pipe may be a metal pipe such as a stainless steel pipe, or may be a resin pipe.

In this embodiment, since the purifier 50 is arranged inside the condensed water tank 15, even if the purifier 50 is frozen at the time of installation of the fuel cell system 200, water is not supplied to the condensed water tank 15 from the outside. is supplied and water is stored in the condensed water tank 15, the heat of the water is efficiently transmitted to the purifier 50, and the purifier 50 can be quickly unfrozen.

Even before the purifier 50 is completely unfrozen, if the first on-off valve 27 is closed, the second on-off valve 28 is opened, and the pump 25 is operated, water will flow through a slight gap created by the melting of the ice. is sucked into the pump 25. Water is returned to the condensed water tank 15 via the first water path 17 and the second water path 19 by the action of the pump 25 .

By circulating the water in the circulation circuit in this way, freezing of the purifier 50 can be eliminated in a short time. At this time, the heater 29 of the purified water tank 195 may be on.

[1-2. motion]
The operation of the hydrogen generator 101 configured as described above will be described below.

In the hydrogen generator 101, in order to obtain the necessary amount of hydrogen, the raw material is supplied from the raw material supply port 104 and the reforming water is supplied from the reforming water supply port 103 in an appropriate ratio between the inner cylinder 105 and the middle cylinder 107. supply to

The reforming water supplied from the reforming water supply port 103 evaporates into water vapor in the water evaporator 123 arranged above between the inner cylinder 105 and the middle cylinder 107, and is mixed with the raw material.

The mixed gas of the raw material and steam is supplied to the reforming section 120 arranged in the lower part between the inner cylinder 105 and the middle cylinder 107, and the steam reforming reaction is performed in the reforming section 120 to convert CO and hydrogen. It becomes a reformed gas containing The reformed gas produced in reforming section 120 flows toward through hole 109 of bottom plate 108 of middle cylinder.

After the reformed gas passes through the through hole 109 , the flow direction of the reformed gas reverses from downward to upward in the vertical direction, and flows between the middle tube 107 and the outer tube 115 toward the lead-out portion 112 . flow.

Then, the reformed gas has its CO concentration reduced by the shift conversion catalyst filled in the shift conversion section 125 arranged between the middle cylinder 107 and the outer cylinder 115 . CO is removed to a CO concentration of about several ppm by the selective oxidation catalyst filled in the selective oxidation unit 126 arranged in the upper part of the outer cylinder 115, and the hydrogen generator 101 outside of

The fuel gas produced by the hydrogen generator 101 is supplied to the fuel cell 10 , and the fuel gas not used in the fuel cell 10 (anode off-gas) is supplied to the heating unit 102 .

The combustion exhaust gas generated by the combustion of the burner of the heating unit 102 passes from the heating unit 102 through the inside (inside) of the combustion tube 130, and after exiting the combustion tube 130, is in a high temperature state and flows into the lower part of the inner tube 105 and the bottom plate of the inner tube. It hits a heat insulator 140 located on the top surface of 106 .

Then, the combustion exhaust gas passes through the passage formed by the outer peripheral surface of the combustion cylinder 130 and the inner peripheral surface of the inner cylinder 105, and passes through the reforming section 120, the shift conversion section 125, and the selective oxidation section 126. After being heated, it is exhausted to the outside of the hydrogen generator 101 from the upper right exhaust port in the drawing.

Regarding the fuel cell system 200 equipped with the hydrogen generator 101 that operates as described above,
Its operation will be described below.

When the fuel cell system 200 equipped with the hydrogen generator 101 is started, the controller 41 burns the fuel gas with the burner of the heating unit 102 to generate flue gas, and the heat from the combustion and the flue gas are generated. This heat raises the temperature of the water evaporator 123 , the reformer 120 , the shift converter 125 and the selective oxidizer 126 .

At this time, the temperature detected by the reforming temperature detector 121 is monitored until it reaches the predetermined temperature a. Here, the predetermined temperature a is desirably higher than the temperature (for example, 100° C.) at which the reforming catalyst does not deteriorate due to condensation water and lower than the temperature (for example, 500° C.) at which the reforming catalyst does not deposit carbon.

On the other hand, the controller 41 closes the first on-off valve 27, opens the second on-off valve 28, operates the pump 25, and supplies the purified water tank 195 with the water in the condensed water tank 15 purified by the purifier 50. supply.

The reason why water is supplied to the purified water tank 195 at the start of operation is that the water level in the purified water tank 195 has decreased due to evaporation or the like during the previous operation of the fuel cell system 200 . At this time, the amount of water supplied is set to an amount (predetermined amount) smaller than the volume of the space 150 . When the amount of water supplied reaches a predetermined amount, the supply of water to the purified water tank 195 is stopped by stopping the pump 25 .

Here, in the unlikely event that the first on-off valve 27 does not close and remains open and the second on-off valve 28 does not open and remains closed, water is supplied to the hydrogen generator 101. .

However, at this time, since the amount of water supplied to the hydrogen generator 101 is smaller than the volume of the space 150, the water level of the water accumulated on the upper surface of the bottom plate 108 of the middle cylinder or the bottom plate 116 of the outer cylinder is It is lower than the lower end of 120 and the lower end of shift conversion section 125, and can prevent the catalyst of reforming section 120 and the catalyst of shift conversion section 125 from being submerged in water, thereby suppressing deterioration of the catalyst due to submersion.

Further, when the fuel cell system 200 is operated with water in the space 150, that is, when the heating unit 102 performs a heating operation, the temperature of the space 150 is filled with water, so the water evaporates. until the temperature at which water evaporates does not rise above 100°C.

If the temperature detected by the reforming temperature detection unit 121 does not rise to a predetermined temperature after a predetermined time has passed since the burner of the heating unit 102 started burning, the controller 41 determines that the hydrogen generator 101 is malfunctioning. It can be determined that water has entered the

At this time, the controller 41 is abnormally stopped, so that it can be determined that the reforming water has flowed into the reforming catalyst layer 7, and the operation cannot be performed until maintenance, thereby suppressing deterioration of catalyst performance.

[1-3. effects, etc.]
As described above, the hydrogen generator 101 of the present embodiment includes the reforming section 120 that generates the reformed gas from the raw material and steam, the shift conversion section 125 that reduces the concentration of carbon monoxide contained in the reformed gas, and the It has a selective oxidation section 126 , a water evaporator 123 that generates steam from reformed water, a reformed water supply port 103 that supplies reformed water to the water evaporator 123 , and a heating section 102 .

A space portion 150 for storing reformed water that has accidentally flowed in is formed at a position lower than the lowermost portions of the reforming section 120 and the shift converting section 125 in the portion where the reforming section 120 and the shift converting section 125 communicate with each other.

As a result, reformed water that has accidentally flowed in can be stored in the space 150 to prevent the reformer 120, the shift converter 125, and the selective oxidizer 126 from being submerged.

Further, in the hydrogen generator 101 of the present embodiment, the reforming temperature detection unit 121 detects the temperature of the space 150, and the reforming temperature detection unit 121 detects the and a controller 41 configured to determine that there is an abnormality if the temperature to be measured does not rise to a predetermined temperature.

As a result, if the temperature detected by the reforming temperature detection unit 121 has not risen to a predetermined temperature after a predetermined time has elapsed since the heating operation of the heating unit 102 was started, the reforming water has erroneously flowed into the hydrogen generator 101. can be judged.

Further, in the present embodiment, the number of times the controller 41 determines that there is an abnormality is counted, and if the number of times that the controller 41 determines that there is an abnormality exceeds a predetermined number of times, the operation of the hydrogen generator 101 may be prohibited.

As a result, it is possible to determine that the reforming water has flowed into the catalyst, prevent operation until maintenance, and suppress performance deterioration of the catalyst.

Moreover, in the present embodiment, the fuel cell system 200 may include the fuel cell 10 that generates power using the hydrogen-containing gas discharged from the hydrogen generator 101 .

In the present embodiment, the fuel cell system 200 includes a circulation path (cooling water circuit 31) through which purified water for cooling the fuel cell 10 circulates, and a circulation path (cooling water circuit 31) provided in the circulation path (cooling water circuit 31). a condensed water tank 15 for storing water obtained by condensing the water vapor contained in the exhaust gas discharged from the fuel cell 10; a purifier 50 for purifying the water in the condensed water tank 15; A supply path for supplying the water in the condensed water tank 15 to the purified water tank 195 (a portion up to the branch position BP in the first water path 17 and an upstream portion 191 of the second water path 19), and a branched from the supply path The reformed water path connected to the reformed water supply port 103 (the portion from the branch position BP in the first water path 17 to the reformed water supply port 103) and the water supply destination in the condensed water tank 15 are purified. A flow path switch (first on-off valve 27 and second on-off valve 28) that selects and switches between the water tank 195 and the reforming water supply port 103, and the flow path switch selects the purified water tank. (the first on-off valve 27 is closed and the second on-off valve 28 is open), the water in the condensed water tank 15 is supplied to the purified water tank 195, and the flow path switch opens the reformed water supply port. is selected (the first on-off valve 27 is open and the second on-off valve 28 is closed), the pump 25 that supplies the water in the condensed water tank 15 to the reforming water supply port 103, and During the period from when the controller 41 starts operating the fuel cell system 200 to when it starts supplying water to the reforming water supply port 103, the purified water tank 195 is filled with the condensed water tank 15. The pump 25 and the channel selector (the first on-off valve 27 and the second on-off valve 28 ) may be controlled so that water is supplied at a water supply rate smaller than the volume of the space 150 .

As a result, the controller 41 can control the supply of water to the purified water tank 195 so that the capacity of the space 150 of the hydrogen generator 101 is less than that of the space 150 after the operation of the fuel cell system 200 is started. Therefore, submergence of the reforming section 120 and the carbon monoxide reduction section (the shift conversion section 125 and the selective oxidation section 126) can be suppressed.

Note that the above-described embodiment is for illustrating the technology in the present disclosure, and various changes, replacements, additions, omissions, etc. can be made within the scope of the claims or equivalents thereof.

INDUSTRIAL APPLICABILITY The present disclosure is applicable to hydrogen generators that generate hydrogen-containing gas through a steam reforming reaction. Specifically, the present disclosure is applicable to fuel cell systems and the like.

REFERENCE SIGNS LIST 10 fuel cell 12 fuel gas supply path 14 oxidant gas supply path 15 condensed water tank 16 anode offgas path 17 first water path 18 cathode offgas path 19 second water path 20 air supplier 21 temperature sensor 23 temperature sensor 24 condensed water path 25 pump 27 first on-off valve 28 second on-off valve 29 heater 31 cooling water circuit 33 heat exchanger 35 heat recovery channel 36 water supply channel 37 pump 38 on-off valve 39 pump 41 controller 45 temperature sensor 50 purifier 67 drain path 101 hydrogen Generation device 102 Heating unit 103 Reforming water supply port 104 Raw material supply port 105 Inner cylinder 106 Inner cylinder bottom plate 107 Middle cylinder 108 Middle cylinder bottom plate 109 Through hole 112 Outlet part 115 Outer cylinder 116 Outer cylinder bottom plate 118 Combustion fan 119 Air supply port 120 Reforming section 121 Reforming temperature detection section 122 Combustion detection section 123 Water evaporation section 124 Shift temperature detection section 125 Shift conversion section 126 Selective oxidation section 130 Combustion tube 140 Heat insulating material 150 Space section 191 Upstream section 193 Downstream section 195 Purified water tank 200 Fuel Battery system 311 Sending route 312 Returning route 351 Sending route 352 Returning route BP Branch position

Claims (6)

a reforming unit that reacts the raw material and steam to produce a hydrogen-containing reformed gas;
a carbon monoxide reduction unit that reduces the concentration of carbon monoxide contained in the reformed gas;
a water evaporator that generates steam from the supplied reforming water, mixes the generated steam and the raw material, and supplies the mixture to the reformer;
a reformed water supply port for supplying the reformed water to the water evaporator;
a heating unit that heats the reforming unit, the carbon monoxide reducing unit, and the water evaporating unit;
a controller;
A hydrogen generator having
A space portion for storing the reforming water that has flowed therein is formed at a position lower than the lowermost portions of the reforming portion and the carbon monoxide reduction portion in the portion where the reforming portion and the carbon monoxide reduction portion communicate,
a temperature detector that detects the temperature of the space,
The controller is configured to determine that there is an abnormality if the temperature detected by the temperature detector does not rise to a predetermined temperature after a predetermined time has elapsed since the heating operation of the heating unit was started. A hydrogen generator characterized by:
2. The hydrogen generator according to claim 1 , wherein the controller counts the number of times it is determined to be abnormal, and prohibits the operation of the hydrogen generator when the number of times it is determined to be abnormal exceeds a predetermined number of times.
The hydrogen generator according to claim 1 or 2 ;
a fuel cell that generates electricity using the hydrogen-containing gas discharged from the hydrogen generator;
A fuel cell system with
a circulation path through which purified water for cooling the fuel cell circulates;
a purified water tank provided in the circulation path and storing the purified water;
a condensed water tank for storing water obtained by condensing water vapor contained in the exhaust gas discharged from the fuel cell;
a purifier for purifying water in the condensate tank;
a supply path for supplying the water in the condensed water tank to the purified water tank;
a reforming water route branched from the supply route and connected to the reforming water supply port;
a flow path selector for selecting and switching a supply destination of water in the condensed water tank to either the purified water tank or the reformed water supply port;
When the flow path selector selects the purified water tank, the water in the condensed water tank is supplied to the purified water tank, and the flow path selector selects the reformed water supply port. a pump for supplying water in the condensed water tank to the reforming water supply port,
further comprising
The controller supplies water in the condensed water tank to the purified water tank during a period from the start of operation of the fuel cell system to the start of water supply to the reforming water supply port. 4. The fuel cell system according to claim 3 , wherein said pump and said flow path switch are controlled so as to supply water at a rate smaller than the volume of said space.
a reforming unit that reacts the raw material and steam to produce a hydrogen-containing reformed gas;
a carbon monoxide reduction unit that reduces the concentration of carbon monoxide contained in the reformed gas;
a water evaporator that generates steam from the supplied reforming water, mixes the generated steam and the raw material, and supplies the mixture to the reformer;
a reformed water supply port for supplying the reformed water to the water evaporator;
a heating unit that heats the reforming unit, the carbon monoxide reducing unit, and the water evaporating unit;
a space provided on a flow path communicating between the reforming section and the carbon monoxide reducing section and at a position lower than the lowermost portions of the reforming section and the carbon monoxide reducing section;
with
The space portion has a convex portion for storing the reforming water that has flowed in,
Hydrogen generator.
a heating unit;
a cylindrical inner cylinder provided so as to surround the heating unit and provided with an inner cylinder bottom plate;
an outer cylinder provided outside the inner cylinder and provided with an outer cylinder bottom plate;
A middle cylinder bottom plate provided between the inner cylinder and the outer cylinder, a through hole provided on the middle cylinder bottom plate in a region immediately below the inner cylinder bottom plate, and a periphery of the through hole on the inner cylinder side a middle cylinder provided so as to surround the middle cylinder and including a projection protruding from the bottom plate of the middle cylinder, and a gas inlet provided on the projection at a height not in contact with the bottom plate of the middle cylinder;
a reforming unit provided between the inner cylinder and the middle cylinder for reacting the raw material and steam to generate a reformed gas containing hydrogen;
a carbon monoxide reduction unit provided between the middle cylinder and the outer cylinder for reducing the concentration of carbon monoxide contained in the reformed gas;
a water evaporator provided between the inner cylinder and the inner cylinder for generating steam from the supplied reforming water, mixing the generated steam and the raw material, and supplying the mixture to the reforming unit;
a reforming water supply port provided in the outer cylinder so as to supply the reforming water to the water evaporator from the outside;
provided between the inner cylinder and the middle cylinder at a position lower than the lowermost portions of the reforming section and the carbon monoxide reduction section, and the inner cylinder, the middle cylinder, the bottom plate of the middle cylinder, and the convex portion an enclosed space for storing the reforming water that has flowed in;
A hydrogen generator.

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