JP2001023668A - Fuel cell power generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a price of a system and enhance exhaust heat recovering efficiency by rationally improving exhaust heat recovering constitution. SOLUTION: This fuel cell power generating system is constituted so that a fuel cell power generating part 4 for generating power by the electrochemical reaction of hydrogen in a supplied hydrogen-containing gas with oxygen in a supplied oxygen-containing gas is installed, exhaust heat of the fuel cell power generating part 4 is recovered with heated water, and recovered heat is stored in a hot water storing bath 3. In such system, the heated water is circulated to the fuel cell power generating part 4 as cooling water to recover the exhaust heat of the fuel cell power generating part 4 with the heated water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fuel cell power generation unit which is supplied with a hydrogen-containing gas and an oxygen-containing gas and generates power by causing an electrochemical reaction between hydrogen in the hydrogen-containing gas and oxygen in the oxygen-containing gas. The present invention relates to a fuel cell power generation device provided so that heated water recovers exhaust heat of the fuel cell power generation unit and is stored in a hot water storage tank.

[0002]

2. Description of the Related Art In such a fuel cell power generator, as shown in FIG. 8, hydrogen in a hydrogen-containing gas supplied through a hydrogen-containing gas passage 1 and oxygen-containing gas supplied through an oxygen-containing gas passage 2 are used. A fuel cell power generation unit 4 for generating electricity by electrochemical reaction with oxygen in the air, and recovering the heated water from the exhaust heat of the fuel cell power generation unit 4 and then storing it in the hot water storage tank 3. It is. The fuel cell power generation unit 4 is provided with a water cooling unit 5 for flowing cooling water and cooling the fuel cell power generation unit 4 with water.

Conventionally, there has been provided a heat exchanger 51 for heat recovery of the power generation unit, which recovers heat from the cooling water discharged from the water cooling unit 5 of the fuel cell power generation unit 4 to the heated water. That is, the water cooling unit 5
And a heat generating unit heat recovery heat exchanger 51, and a circulation pump 52.
And a heat exchanger 51 for recovering exhaust heat from the power generation unit and the hot water storage tank 3 are connected by a heated water circulation path 55 in which a circulation pump 54 is interposed. And
In the heat-exchanging heat exchanger 51 for heat recovery of the power generation unit, the waste heat of the fuel cell power generation unit 3 is recovered to the heated water via the cooling water, and the heated water thus recovered is stored in the hot water storage tank 3. I was trying to do it.

In FIG. 8, reference numeral 17 denotes a reforming reaction of a hydrocarbon-based raw fuel gas supplied through a gas passage 16 with steam to form a gas containing hydrogen gas and carbon monoxide gas. It is a reformer that performs, although not shown,
In order to reduce the carbon monoxide contained in the gas reformed by the reformer 17, a shift converter, a CO removing device, etc. are provided, and the hydrogen content having a reduced carbon monoxide gas content is provided. Gas is supplied to the fuel cell power generation unit 4 through the hydrogen-containing gas passage 1. 17b in the figure is
It is a burner provided in the reformer 17 to provide heat required for the reforming reaction.
The exhausted hydrogen-containing gas discharged from the fuel cell power generation unit 4 is supplied through the exhausted hydrogen-containing gas passage 7, and the combustion air is supplied through the combustion air passage 25.

Conventionally, waste heat is discharged from the exhaust gas containing gas discharged from the fuel cell power generation unit 4 through the exhaust gas passage 9 and the combustion gas of the burner 17 b discharged through the waste gas passage 30 to the cooling water. An exhaust gas cooling exchanger 57 to be recovered is provided, and the exhaust gas cooling heat exchanger 57 and an exhaust gas exhaust heat recovery heat exchanger 58 provided in the heated water circulation path 55 so that the heated water flows therethrough, The cooling water circulation path 60 is provided with a circulation pump 59 interposed therebetween. Then, in the exhaust gas exhaust heat recovery heat exchanger 58, the heated oxygen-containing gas discharged from the fuel cell power generation unit 4 and the heat of the combustion gas discharged from the burner 17b are recovered by the heated water via the cooling water. Was like that.

[0006]

Conventionally, a heat exchanger 51 for recovering waste heat from a power generation unit for recovering heat from cooling water discharged from a fuel cell power generation unit 4 to water to be heated is provided separately. The provision of the heat exchanger 51 for exhaust heat recovery partially complicates the configuration of the apparatus, and thus increases the price of the fuel cell power generator. Further, since the exhaust heat of the fuel cell power generation unit is recovered to the heated water via the cooling water, there is a problem that the exhaust heat recovery efficiency is low.

The present invention has been made in view of the above circumstances, and an object of the present invention is to rationally improve the configuration of exhaust heat recovery to reduce the cost of the apparatus and improve the efficiency of exhaust heat recovery. .

[0008]

Means for Solving the Problems [Invention according to claim 1]
The characteristic configuration according to claim 1 is configured such that the heated water flows through the fuel cell power generation unit as cooling water, and the heated water recovers exhaust heat of the fuel cell power generation unit. Is to be.

According to the first aspect of the present invention, the heated water flows through the fuel cell power generation section as cooling water, and the exhaust heat of the fuel cell power generation section is directly recovered by the heated water. Therefore, the heat exchanger for recovering the exhaust heat of the power generation unit, which is conventionally provided, becomes unnecessary, so that the cost of the apparatus can be reduced, and the exhaust heat of the fuel cell power generation unit can be recovered into the heated water via the cooling water. The exhaust heat recovery efficiency can be improved as compared with the related art.

According to a second aspect of the present invention, the heated water is discharged from the fuel cell power generation section or the exhausted hydrogen-containing gas discharged from the fuel cell power generation section. The configuration is such that the heated water recovers the exhaust heat of the fuel cell power generation unit by flowing the gas so as to be heated by the exhausted oxygen-containing gas.

According to the second aspect of the present invention, the water to be heated is heated by the exhausted hydrogen-containing gas discharged from the fuel cell power generation unit or the exhausted oxygen-containing gas discharged from the fuel cell power generation unit. And the exhaust heat of the fuel cell power generation unit discharged by the exhausted hydrogen-containing gas or the exhausted oxygen-containing gas is directly recovered from the exhausted hydrogen-containing gas or the exhausted oxygen-containing gas into the heated water. Accordingly, the heat exchanger for exhaust gas exhaust heat recovery, which is conventionally provided, is not required, and the cost of the apparatus can be further reduced. Further, the exhaust heat recovery efficiency is further improved as compared with the related art in which the exhaust heat of the fuel cell power generation unit discharged with the exhausted hydrogen-containing gas or the exhausted oxygen-containing gas is recovered into the heated water via the cooling water. Now you can do it.

According to a third aspect of the present invention, there is provided a characteristic configuration in which tap water is passed as the heated water at its supply pressure. According to the characteristic configuration of the third aspect, since a pump or the like for flowing the heated water is not required, the cost of the apparatus can be further reduced.

The invention according to claim 4 is characterized in that the heated object taken out from the bottom of the hot water storage tank so that hot water forms a temperature stratification and is stored in the hot water storage tank. After flowing water so as to recover the exhaust heat of the fuel cell power generation unit, a heated water circulation means for circulating the heated water is provided in a state of being supplied to an upper portion of the hot water storage tank,
A hot water supply path is connected to an upper part of the hot water storage tank.

According to the fourth aspect of the present invention, the heated water taken out from the bottom of the hot water storage tank is passed through the fuel cell power generation unit so as to recover the exhaust heat, and heated. By circulating the heated water in a state where it is supplied to
Hot water is stored in a hot water tank so as to form a temperature stratification, and hot water at the upper portion of the hot water tank is supplied to a hot water demand destination through a hot water supply channel. Therefore, compared to a case where hot water is stored without forming a temperature stratification in the hot water storage tank, high-temperature hot water can be efficiently supplied to the demand destination in a state where the temperature is stable.

According to a fifth aspect of the present invention, after recovering the exhaust heat of the fuel cell power generation unit,
Temperature detecting means for detecting the temperature of the heated water stored in the hot water storage tank, water supply amount adjusting means for adjusting the flow rate of the heated water, and the detected temperature of the temperature detecting means is set to a set temperature. And a control means for controlling the water supply amount adjusting means.

According to the characteristic configuration of the fifth aspect, after the exhaust heat of the fuel cell power generation unit is recovered, the temperature of the heated water is set such that the temperature of the heated water stored in the hot water storage tank reaches the set temperature. Since the flow rate is adjusted, the temperature of hot water from the hot water storage tank is stabilized. Further, since the temperature of the fuel cell power generation unit is also adjusted to a predetermined temperature, the power generation output is stabilized.

According to a sixth aspect of the present invention, the fuel cell power generation section is constituted by a cell having a polymer electrolyte layer. In other words, a so-called polymer electrolyte type fuel cell power generation device in which the fuel cell power generation unit is composed of cells having a polymer electrolyte layer is, for example, a cell in which the fuel cell power generation unit has a phosphoric acid electrolyte layer. The operating temperature of the fuel cell power generation unit is lower than that of a so-called phosphoric acid type fuel cell power generator configured as described above. For example, the operating temperature of the phosphoric acid type fuel cell power generation unit is about 180 to 200 ° C., whereas the operating temperature of the polymer electrolyte type fuel cell power generation unit is about 70 to 80 ° C. Therefore, in the conventional configuration in which the exhaust heat of the fuel cell power generation unit is recovered into the heated water via the cooling water in the polymer electrolyte fuel cell power generation unit, the temperature of the heated water after the recovery of the exhaust heat is low. However, there is a disadvantage that the temperature of hot water supplied from the hot water storage tank is low. Therefore, when the present invention is implemented in a polymer electrolyte fuel cell power generation unit, the temperature of the heated water after the exhaust heat recovery is increased by directly collecting the waste heat of the fuel cell power generation unit into the heated water. This is preferable because the temperature of hot water from the hot water storage tank can be increased.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment in which the present invention is applied to a polymer electrolyte fuel cell power generator based on FIGS. 1, 2, 4 to 7 will be described below. An embodiment will be described. As shown in FIGS. 1 and 2, the fuel cell power generator includes a fuel gas (corresponding to a hydrogen-containing gas) supplied through a fuel gas passage 1 and a reaction gas supplied through a reaction air passage 2. A fuel cell power generation unit 4 for generating electricity by electrochemically reacting oxygen in the working air (corresponding to oxygen-containing gas) with the heated water is used to recover the exhaust heat of the fuel cell power generation unit 4. It is configured to be stored in. The hot water stored in the hot water storage tank 3 is configured to be supplied to a hot water demand destination through the hot water supply channel 37.

The fuel cell power generation unit 4 is provided with a water cooling unit 5 for flowing cooling water to cool the fuel cell power generation unit 4 with water.
In the present invention, the heated water is passed through the water cooling unit 5 as cooling water, and the heated water recovers the exhaust heat of the fuel cell power generation unit 4. That is, after the exhaust heat of the fuel cell power generation unit 4 is recovered, the heated water passage 6 through which the heated water flows is supplied to the hot water storage tank 3 so that the heated water flows through the water cooling unit 5. It is connected to the water cooling unit 5.

Further, the fuel cell power generation unit 4 is connected to the exhaust fuel gas passage 7.
A fuel gas heat exchanger 8, which heats the heated water flowing through the heated water passage 6 by the discharged fuel gas discharged through
An exhaust air heat exchanger 10 is provided for heating water to be heated flowing through the heated water passage 6 by exhaust reaction air discharged from the fuel cell power generation unit 4 through the exhaust reaction air passage 9. The exhaust heat of the fuel cell 4 is directly recovered to the heated water from the exhaust fuel gas discharged from the fuel cell power generation unit 4 and the exhaust reaction air.

As will be described in detail later, the exhaust fuel gas passage 7 is connected to a burner 17b of a reformer 17 for steam reforming a raw fuel gas such as natural gas, so that the exhaust gas discharged from the fuel cell power generation unit 4 is discharged. The fuel gas is burned by the burner 17b. And, from the burner 17b, the exhaust combustion gas path 3
0, the exhaust gas heat exchanger 33 for heating the water to be heated flowing through the heated water passage 6 by the combustion gas discharged through
And the exhaust heat of the burner 17b is directly recovered by the heated water.

A water supply is connected to the heated water passage 6, so that tap water as the heated water flows through the heated water passage 6 at its supply pressure. In the heated water channel 6, a proportional valve 34 (corresponding to a water supply amount adjusting means) for adjusting the amount of water supplied to the heated water channel 6 and the exhaust heat of the fuel cell power generation unit 4 are collected. A temperature sensor 35 (corresponding to a temperature detecting means) for detecting the temperature of the heated water stored in 3 is provided. Further, a control device 36 (corresponding to control means) for adjusting the opening of the proportional valve 34 is provided so that the temperature detected by the temperature sensor 35 becomes a set temperature (for example, 80 ° C.).

The fuel cell power generation section 4 will be described with reference to FIGS. First, the cell C of the fuel cell will be described. The cell C has an oxygen electrode 42, a current collector 44 and an oxygen electrode side separator 4 on one surface of the polymer film 41.
5 and the fuel electrode 43 and the current collector 44 on the other surface.
And a fuel electrode side separator 46.
A plurality of such cells C are juxtaposed in a stacked state, and a power collection unit 47 for extracting power is provided at each of both ends in the stacking direction to constitute the fuel cell power generation unit 4.

The oxygen electrode side separator 45 has an oxygen electrode side gas flow groove 45s which forms an oxygen electrode side flow path through which air for reaction flows is formed on the surface on the oxygen electrode 42 side, and is formed on the opposite surface. ,
A cooling water flow groove 45w that forms a cooling water flow path is formed. The fuel electrode side separator 46 has a surface on the fuel electrode 43 side,
A fuel electrode-side gas flow groove 46f that forms a fuel electrode-side flow path through which fuel gas flows is formed, and cooling on the opposite surface is plane-symmetric with the cooling water flow groove 45w of the oxygen electrode-side separator 45. A cooling water flow groove 46w for forming a water flow path is formed.

Further, each of the polymer film 41, the oxygen electrode side separator 45, and the fuel electrode side separator 46 is provided with six pieces penetrating in the thickness direction in a state where they are connected in the stacking direction when they are stacked. Holes 41h, 45h and 46h are formed. As viewed in the stacking direction, two of the six holes 41h, 45h, and 46h formed in the polymer film 41, the oxygen electrode-side separator 45, and the fuel electrode-side separator 46 are two of the oxygen electrode-side gas flow grooves 45s. The other two portions overlap with both ends of the flow path of the fuel electrode side gas flow groove 46f, respectively, and the other two pieces overlap with the cooling water flow grooves 4 respectively.
5w and 46w respectively overlap with both ends of the flow path.

Accordingly, the fuel cell power generation section 4 has six passages in which the holes 41h, 45h, 46h of the polymer membrane 41, the oxygen electrode side separator 45, and the fuel electrode side separator 46 are respectively connected in the stacking direction. Two of them are individually connected to both ends of the flow path of each oxygen electrode side gas flow groove 45s, and the other two are each fuel electrode side gas flow groove 46s. To the two ends of the flow path of
The book is in communication with both ends of the flow path of each cooling water flow groove 45w, 46w. In addition, each oxygen electrode side gas flow groove 4
Two passages respectively communicating with both ends of the 5 s flow passage are formed as an oxygen electrode side communication passage Ts and a fuel electrode side gas flow groove 46.
The two passages respectively communicating with both ends of the flow path of f are connected to the fuel electrode side communication path Tf and the two passages respectively communicating with both ends of the flow paths of the cooling water flow grooves 45w and 46w. The passages are respectively referred to as cooling water side communication passages Tw.

The polymer membrane 41 is formed of a fluororesin-based ion exchange membrane (such as Nafion). The oxygen electrode 42 and the fuel electrode 43 are formed of a porous conductive material made of carbon, and carry an electrode catalyst made of platinum. The current collector plate 44 is formed of porous carbon paper or the like, and the oxygen electrode side separator 45 and the fuel electrode side separator 46 are formed of a dense airtight conductive material made of carbon or the like.

Further, as shown in FIG. 7, end plates 49 are provided at both ends in the stacking direction of the fuel cell power generation unit 3. One end plate 49 has an air connection portion 48s that is connected to one end of two oxygen electrode side communication passages Ts and one end of two fuel electrode side communication passages Tf. Connecting portion 48f for fuel gas communicating with the cooling water and two cooling water communication passages T
w connection part 4 for cooling water which is connected to one end of w
8w. Further, the other end plate 49 has an air connection portion 48 s that is connected to the other end of the two oxygen electrode side communication passages Ts and the other of the two fuel electrode side communication passages Tf. A fuel gas connecting portion 48f communicating with the end portion and a cooling water connecting portion 48w communicating with the other end portion of the two cooling water communication passages Tw are provided.

One of the two air connection portions 48s is used for supplying reaction air, and the other is used for discharging reaction air, and one of the two fuel gas connection portions 48f is used. Is used for supplying fuel gas, the other is used for discharging fuel gas, and two cooling water connections 48 are used.
One of w is used for supplying cooling water, and the other is used for discharging cooling water.

The reaction air is supplied from the supply air connection 48s, the fuel gas is supplied from the supply fuel gas connection 8f, and the cooling water is supplied from the supply cooling water connection 8w. I do. Then, the reaction air gas is supplied from one of the oxygen electrode side communication passages Ts to the oxygen electrode side flow path of each cell C and flows through the oxygen electrode side flow path as indicated by a solid line arrow in each drawing. After that, it flows out to the other oxygen electrode side communication passage Ts, flows through the oxygen electrode side communication passage Ts, and is discharged from the air connection portion 48s for discharge. Further, the fuel gas is supplied from one fuel electrode side communication passage Tf to the fuel electrode side flow path of each cell C, as indicated by a two-dot chain line arrow in each drawing,
After flowing through the fuel electrode side flow path, the other fuel electrode side communication passage T
f, flows through the fuel electrode side communication passage Tf, and is discharged from the fuel gas connecting portion 48f for discharge. In addition, the cooling water is supplied to the cooling water flow path of each cell C from one cooling water communication path Tw, and flows through the cooling water flow path, as indicated by a chain line arrow in each drawing. It flows out into the cooling water communication passage Tw, flows through the cooling water communication passage Tw, and is discharged from the cooling water connection portion 48w for discharge.

In each cell C, the oxygen contained in the reaction air and the hydrogen contained in the fuel gas are mixed with each other while the polymer film 41 is moistened by the moisture contained in the humidified fuel gas as described later. Is generated by the electrochemical reaction of
In addition, the flow of the cooling water maintains the temperature of each cell C at a predetermined temperature. The DC power generated by the fuel cell power generation unit 4 is converted into AC power by the inverter I and supplied.

Therefore, the cooling water flow groove 45w and the cooling water flow groove 46w forming the cooling water flow path are configured to function as the water cooling section 5.

Next, based on FIG.
A configuration for supplying fuel gas to the fuel cell will be described. Hydrocarbon raw fuel gas such as natural gas is supplied to raw fuel gas path 1
The desulfurization raw fuel gas is supplied to a desulfurization device 12 through the gas desulfurizer 1, and the desulfurization raw fuel gas is sent to an ejector 14 through a gas passage 13, where the desulfurization raw fuel gas is sent through a reforming steam passage 15 to be described later. It is mixed with incoming steam and sent to a reformer 17 through a gas passage 16. In the reforming device 17, the raw fuel gas and the steam are subjected to a reforming reaction using the combustion heat of the burner 17b as reaction heat to reform the gas containing hydrogen gas and carbon monoxide gas. The post-gas is passed through a gas passage 18 to be transformed
And in the shift converter 19, a shift reaction is performed between the carbon monoxide gas and the steam in the sent gas to convert the gas into a gas containing hydrogen gas and carbon dioxide gas. CO removal device 2 through gas path 20
The carbon monoxide gas in the sent gas is selectively oxidized by the air from the selective oxidation air passage 22 in the CO removing device 21. Then, after the humidifier 23 humidifies the hydrogen-containing gas thus generated with a low carbon monoxide gas content as a fuel gas, the fuel gas passage 1
The fuel gas is supplied to the fuel cell power generation section 4 from the fuel gas connection section 48f for supply.

An air supply blower 24 is provided, and the blower 24 and an air connection 48 for supply of the fuel cell power generation unit 4 are provided.
s are connected by the reaction air passage 2, the blower 24 and the gas passage 20 are connected by the selective oxidation air passage 22,
The burner 17b of the reformer 17 is connected to a combustion air passage 25.

In order to supply the exhaust gas discharged from the fuel cell power generation section 4 to the burner 17b of the reformer 17, the fuel gas connection section 48f for discharge of the fuel cell power generation section 4 and the burner 17b are discharged. In order to guide the exhaust reaction air discharged from the fuel cell power generation unit 4 through the gas passage 7, the exhaust reaction air passage 9 is connected to the exhaust air connection unit 48s.
In addition, in giving the reaction heat necessary for the reforming reaction in the reformer 17, a burner 17b of the reformer 17 is provided with a gas supply path for replenishing the raw fuel gas in order to compensate for the shortage of the exhaust gas alone. 26 is connected. Burner 17
b, an exhaust combustion gas passage 30 for discharging combustion gas.
Is connected.

A steam-water separator 27 for condensing and separating moisture in the flowing exhaust gas is provided in the exhaust gas path 7.
The exhaust-reaction air passage 9 is provided with a steam-water separator 28 for condensing and separating moisture in the exhaust-reaction air flowing therethrough, and the condensed water separated by the steam-water separators 27, 28 is separated from the steam. A steam-water separator 29 for storage is provided. And steam-water separator 29
Is connected to the ejector 14 through a reforming steam passage 15, and the water flowing therethrough is discharged from the reformer 17 and passed through the gas passage 18. A water-evaporating heat exchanger 31 for evaporating by heating with the flowing high-temperature reforming gas is provided, the water stored in the steam separator 29 is evaporated, and the steam is used as an ejector for the reforming reaction. 14.
The water-evaporating heat exchanger 31 is heated by the high-temperature reforming gas discharged from the reformer 17 and flowing through the gas passage 18.
It has a function of preheating raw fuel gas supplied to the reformer 17 through the gas passage 13. Incidentally, 32 in FIG.
Is a supply channel for supplying pure water to the steam separator 29.

As shown in FIGS. 1 and 2, an exhaust combustion gas passage 30 is provided with an exhaust combustion gas heat exchanger 33 for recovering exhaust heat from the exhaust combustion gas.
An exhaust fuel gas heat exchanger 8 for recovering exhaust heat from the exhaust fuel gas is provided on the upstream side of the steam separator 27, and is provided upstream of the steam separator 28 in the exhaust reaction air passage 9. On the side, an exhaust air heat exchanger 10 for recovering exhaust heat from exhaust reaction air is provided. Then, the heated water flows through the exhaust combustion gas heat exchanger 33, the exhaust fuel gas heat exchanger 8, the exhaust air heat exchanger 10, and the water cooling unit 5 of the fuel cell power generation unit 4 in this order. To be supplied to the tank 3, in the heated water channel 6, the exhaust combustion gas heat exchanger 33, the exhaust fuel gas heat exchanger 8, the exhaust air heat exchanger 10, and the cooling water connection 4 for supply
8w, a connecting portion 48w for cooling water for discharge, and a hot water receiving port 3i of the hot water storage tank 3 are connected in order. Therefore, the heated water is
The exhaust heat is recovered from the exhaust gas in the exhaust gas heat exchanger 33, the exhaust heat is recovered from the exhaust gas in the exhaust gas heat exchanger 8, and the exhaust reaction air is recovered in the exhaust air heat exchanger 10. After collecting the exhaust heat from the fuel cell power generation unit 4 by flowing it as cooling water in the water cooling unit 5, the exhaust heat is supplied to the hot water storage tank 3 from the hot water inlet 3 i.

Accordingly, the exhaust heat of the fuel cell power generation unit 4 is directly recovered by the heated water, and the exhaust heat of the fuel cell power generation unit 4 discharged by the exhaust fuel gas and the exhaust reaction air is converted into the exhaust fuel gas. In addition to directly recovering the waste water from the exhaust reaction air into the heated water, the waste heat is directly recovered from the combustion gas of the burner 17b of the reformer 17 into the heated water.
Exhaust heat recovery efficiency can be further improved, and the temperature of hot water supplied from hot water storage tank 3 can be further increased.

[Second Embodiment] Hereinafter, based on FIG.
A second embodiment in which the present invention is applied to a polymer electrolyte fuel cell power generator will be described. In the second embodiment, the fuel cell power generation unit 4 and the configuration for supplying each of the fuel gas and the reaction air to the fuel cell power generation unit 4 are configured in the same manner as the first embodiment described above. As in the first embodiment, a heat exchanger 33 for exhaust combustion gas, a heat exchanger 8 for exhaust fuel gas, and a heat exchanger 10 for exhaust air are provided.

Then, the heated water taken out from the hot water outlet 3o at the bottom of the hot water tank 3 is recovered by the exhaust heat of the fuel cell power generation unit 4 so that the hot water forms a temperature stratification and is stored in the hot water tank 3. A heated water circulating means L for circulating the heated water is provided in such a state that the heated water is supplied to the hot water receiving port 3i in the upper part of the hot water storage tank 3 after flowing the hot water. In order to store hot water in the hot water storage tank 3 in a full state, a water supply path 40 for supplying tap water at the water supply pressure is connected to the bottom of the tank, and a hot water supply path 37 is provided at the top of the tank.
Is connected, and hot water in the upper part of the tank is supplied from the hot water supply channel 37 by the water supply pressure from the water supply channel 40.

In addition, the heated water taken out from the hot water outlet 3o is discharged into the heat exchanger 33 for exhaust combustion gas, the heat exchanger 8 for exhaust gas, the heat exchanger 10 for exhaust air, and the fuel cell power generator. 4 in the order of the water cooling section 5 and the hot and cold water inlet 3
i, the heated water circulation path 38
, The hot water outlet 3o, the exhaust gas heat exchanger 3
3. Exhaust gas heat exchanger 8, Exhaust air heat exchanger 10,
Cooling water connection 48 w for supply of fuel cell power generation unit 4, cooling water connection 48 w for discharge, hot water inlet 3 of hot water tank 3
i are connected in order. In the heated water circulation path 38,
A circulation pump 39 is provided. Therefore, the heated water circulation means L is constituted by the heated water circulation path 38 and the circulation pump 39 provided in the heated water circulation path 38.

The water to be heated taken out of the hot / water take-out port 3o is discharged by the circulation pump 39 into the heat exchanger 33 for the exhaust combustion gas, the heat exchanger 8 for the exhaust fuel gas, and the heat exchanger for the exhaust air. After passing through the heater 10 and the water cooling unit 5 of the fuel cell power generation unit 4 in order, and heating, the hot water is supplied from the hot water receiving port 3i, so that the hot water is supplied to the upper side of the hot water storage tank 3 and to the lower side of the hot water storage tank 3. Water is stored separately. The boundary between the hot water layer and the water layer in the hot water storage tank 3 is such that, when the amount of hot water supplied from the hot water supply channel 37 decreases, the boundary moves downward in the tank, and when the amount increases, moves upward in the tank. Move in the direction.

The heated water circulation path 38 is provided with a temperature sensor 35 for detecting the temperature of the heated water stored in the hot water storage tank 3 after recovering the exhaust heat of the fuel cell power generation unit 4.
Indicates that the temperature detected by the temperature sensor 35 is the set temperature (for example, 8
The circulation pump 39 is controlled so as to adjust the flow rate of the heated water so that the temperature becomes 0 ° C.).
Therefore, the circulation pump 39 functions as a water supply amount adjusting unit.

[Another Embodiment] Next, another embodiment will be described. (A) In the above embodiment, in addition to directly collecting the waste heat of the fuel cell power generation unit 4 in the water to be heated in the water cooling unit 5, in addition to directly collecting the waste heat from the waste fuel gas to the heated water. Exhaust gas heat exchanger 8, Exhaust air heat exchanger 10 for directly collecting exhaust heat from exhaust reaction air into heated water, and Exhaust heat from exhaust combustion gas directly into heated water The case of providing the exhaust gas heat exchanger 33 for performing the operation is described above. Instead of this, the exhaust gas heat exchanger 8, the exhaust air heat exchanger 10, and the exhaust combustion gas heat exchanger 3
3 may be omitted, any two may be omitted, or one of them may be omitted.

(B) The heated water is supplied to the heat exchanger 33 for exhaust combustion gas, the heat exchanger 8 for exhaust fuel gas, and the heat exchanger 1 for exhaust air.
In the case where the flow is made to flow through each of the heat exchanger 0 and the water cooling section 5, the flow order is as described in the above-described embodiment. It is not limited to 10 and the water cooling section 5 in this order. For example, the exhaust gas heat exchanger 8, the exhaust air heat exchanger 10,
The exhaust combustion gas heat exchanger 33 and the water cooling unit 5 may be arranged in this order.

(C) A temperature sensor for detecting the temperature of the fuel cell power generation unit 4 is provided in place of the temperature sensor 35 provided in the above embodiment, and the control unit 36 detects the temperature of the fuel cell power generation unit 4 The operation of the proportional valve 34 or the circulation pump 39 may be controlled such that the temperature detected by the temperature sensor becomes the set temperature.

(D) The configuration of the polymer electrolyte fuel cell power generator to which the present invention can be applied is not limited to the configuration exemplified in the above embodiment.
For example, in the above embodiment, the case where the water cooling unit 5 for allowing the cooling water to flow is provided in each of the cells C, but instead, the water cooling unit 5 is provided in the plurality of cells C. It may be configured as follows.

In the above embodiment, the water cooling section 5 is provided with a cooling water flow groove 45 w in the oxygen electrode side separator 45, and
The case where the cooling water flow grooves 46w are respectively formed in the fuel electrode side separator 46 has been exemplified. Instead of this, the cooling water flow groove 45w and the cooling water flow groove 46w are omitted, and the cell C
In between, a metal pipe or a metal chamber through which cooling water flows may be provided as water cooling section 5.

(E) In addition to the natural gas exemplified in the above embodiment, a hydrogen-containing gas produced by reforming a variety of hydrocarbon-based raw fuels such as alcohol can be used as a fuel gas. In addition, a configuration for generating a hydrogen-containing gas using a hydrocarbon-based raw fuel (reforming device 17, shift device 19, CO removing device 21 and the like) is omitted, and pure hydrogen gas is used as a fuel gas. Is also good.

(F) In the present invention, for example, the fuel cell power generation unit 4 may be a fuel cell power generation unit 4 other than a polymer electrolyte type fuel cell power generation device including a cell C having a polymer electrolyte layer. The present invention can also be applied to a phosphoric acid type fuel cell power generation device including a cell C having a phosphoric acid electrolyte layer.

[Brief description of the drawings]

FIG. 1 is a main part view showing an exhaust heat recovery configuration in a fuel cell power generator according to a first embodiment.

FIG. 2 is a diagram showing the overall configuration of the fuel cell power generator according to the first embodiment.

FIG. 3 is a view of a main part showing an exhaust heat recovery configuration in a fuel cell power generator according to a second embodiment.

FIG. 4 is a perspective view showing a configuration of a cell of a fuel cell power generation unit in the fuel cell power generation device according to the embodiment.

FIG. 5 is an exploded perspective view of a main part of a fuel cell power generation unit in the fuel cell power generation device according to the embodiment.

FIG. 6 is an exploded perspective view of a main part of a fuel cell power generation unit in the fuel cell power generation device according to the embodiment.

FIG. 7 is a diagram showing an overall schematic configuration of a fuel cell power generation unit in the fuel cell power generation device according to the embodiment.

FIG. 8 is a view of a main part showing an exhaust heat recovery configuration in a conventional fuel cell power generator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 3 hot water storage tank 4 fuel cell power generating unit 34 water supply amount adjusting means 35 temperature detecting means 36 control means 37 hot water supply path 39 water supply amount adjusting means C cell L heated water circulation means

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Seisaku Higashiguchi 4-1-2, Hiranocho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Inventor Masashi Tatemori Hirano-cho, Chuo-ku, Osaka-shi, Osaka 4-chome 1-2-2 Osaka Gas Co., Ltd. F-term (reference) 5H026 AA06 CC03 CC08 5H027 AA06 BA01 BA09 CC06 DD06 KK41 MM16

Claims (6)

[Claims] 1. A fuel cell power generation section is provided which is supplied with a hydrogen-containing gas and an oxygen-containing gas, and which generates an electrochemical reaction between hydrogen in the hydrogen-containing gas and oxygen in the oxygen-containing gas to generate power. Is a fuel cell power generation device configured to recover exhaust heat of the fuel cell power generation unit and store the waste heat in a hot water tank, wherein the heated water is allowed to flow as cooling water to the fuel cell power generation unit. A fuel cell power generator configured so that the heated water recovers exhaust heat of the fuel cell power generator. 2. Flowing the heated water so as to be heated by the exhausted hydrogen-containing gas discharged from the fuel cell power generation unit or the exhausted oxygen-containing gas discharged from the fuel cell power generation unit, The fuel cell power generator according to claim 1, wherein the heated water is configured to recover exhaust heat of the fuel cell power generator. 3. The fuel cell power generator according to claim 1, wherein tap water is supplied at the supply pressure as the heated water. 4. The heated water taken out from the bottom of the hot water storage tank is passed through the hot water storage tank so as to recover exhaust heat of the fuel cell power generation unit so that hot water is stored in the hot water storage tank by forming a temperature stratification. After flowing, in a state of being supplied to the upper part of the hot water storage tank,
3. The fuel cell power generator according to claim 1, wherein a heated water circulating unit that circulates the heated water is provided, and a hot water supply path is connected to an upper portion of the hot water storage tank. 4. 5. A temperature detecting means for detecting a temperature of water to be heated stored in the hot water storage tank after recovering exhaust heat of the fuel cell power generation unit, and a water supply amount for adjusting a flow rate of the water to be heated. Adjusting means, so that the temperature detected by the temperature detecting means becomes a set temperature,
The fuel cell power generator according to any one of claims 1 to 4, further comprising control means for controlling the water supply amount adjusting means. 6. The fuel cell power generation device according to claim 1, wherein the fuel cell power generation unit comprises a cell having a polymer electrolyte layer.