JP2002280031A - Fuel cell cogeneration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve profitability by avoiding wasteful drainage from an escape piping. SOLUTION: A humidifying mechanism 3 to humidify a high polymer film and a water treatment mechanism 4 to demineralize water to supply to the humidifying mechanism 3 are provided on a fuel cell 1, and a water supply pipe for demineralization to supply water for demineralization is connected to the water treatment mechanism 4. An exhaust heat recovery circuit 12 is provided along the fuel cell 1 and a hot water reservoir tank 2, exhaust heat from the fuel cell 1 is collected as hot water, and the collected hot water is reserved in the hot water reservoir tank 2. A water supply pipe 14 with a check valve 15 is connected to a bottom part of the hot water reservoir tank 2. The escape piping 16 interposing a pressure regulation valve 17 to open by set pressure higher than pressure of the check valve 15 is connected to the water supply pipe 14, when volume increases due to a temperature change of water in accordance with the exhaust heat recovery and pressure in the hot water reservoir tank 2 increases, the water is discharged through the escape piping 15 from the hot water reservoir tank 2, pressure rise in the hot water reservoir tank 2 is prevented, and the water is used as water for demineralization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering waste heat from a polymer electrolyte fuel cell that generates electric power and waste heat, storing the waste heat in a hot water storage tank, and using the waste heat for hot water supply and the like. And a fuel cell cogeneration system.

[0002]

2. Description of the Related Art As a conventional fuel cell cogeneration system, there is one shown in the system configuration diagram of FIG. In FIG. 5, 01 indicates a polymer electrolyte fuel cell, and 02 indicates a closed hot water storage tank.

[0003] The fuel cell 01 is provided with a humidifying mechanism 03 for humidifying the polymer membrane and a water treatment mechanism 04 such as an ion exchange membrane for purifying water supplied to the humidifying mechanism 03. The water treatment mechanism 04 includes a pure water supply pipe 06 provided with a first pump 05 for supplying water for pure water, and a drain pipe 07 for discharging water concentrated with the water treatment. The drain pipe 07 is connected and an open / close valve 08 is interposed.

[0004] An exhaust heat recovery water supply pipe 010 with a second pump 09 interposed between the fuel cell 01 and the hot water storage tank 02 and capable of extracting water from the bottom side of the hot water storage tank 02 is connected to and obtained from the fuel cell 01 and the hot water storage tank 02. A hot water supply pipe 011 for supplying hot water to the upper portion of the hot water storage tank 02 is connected to the fuel cell 0
An exhaust heat recovery circuit 012 is configured to collect the exhaust heat from 1 as hot water and store the collected hot water in the hot water storage tank 02. The heat discharged from the fuel cell 01 includes exhaust heat of the reformer exhaust gas, off-gas exhaust heat, and cooling water exhaust heat, and at least one of them is recovered.

[0005] A hot water supply pipe 013 for supplying hot water to a cooking place, a bathtub, a lavatory, and the like is connected to an upper portion of the hot water storage tank 02, while a water supply pipe for replenishing water reduced by the hot water supply is provided at the bottom of the hot water storage tank 02. 014 is connected, and a check valve 015 that opens as the pressure (for example, 0.2 Mpa) decreases above a set value is interposed in the water supply pipe 014.

A relief pipe 016 is provided between the check valve 015 of the water supply pipe 014 and the hot water storage tank 02, and the relief pipe 016 is set at a set pressure (for example, 0.3 MPa) higher than the pressure of the check valve 015. An open pressure regulating valve 017 is interposed. Thereby, when the volume expands due to the temperature change of the water due to the exhaust heat recovery and the pressure in the hot water storage tank 02 increases, the water is discharged from the hot water storage tank 02 through the discharge pipe 016, and is discharged from the hot water storage tank 02. Is prevented from increasing.

[0007]

However, conventionally, water from the escape pipe 016 has been discarded as it is. For example, if the volume of water is 70 ° C and the temperature is 25 ° C
It becomes 1.02 times of the case. If heating 150 to 250 liters a day, the amount of water discarded was 3 to 5 liters, which was extremely wasteful.

The present invention has been made in view of such circumstances, and an object of the present invention is to avoid wasteful drainage from a relief pipe and improve economic efficiency. The invention according to claim 2 aims to further improve the economy by simplifying the piping and equipment configuration, and the invention according to claim 3 further simplifies the piping configuration to further improve the economy. With the goal.

[0009]

According to the first aspect of the present invention,
In order to achieve the above object, a polymer electrolyte fuel cell, a humidifying mechanism for humidifying a polymer membrane of the polymer electrolyte fuel cell, and water for purifying water supplied to the humidifying mechanism are provided. A treatment mechanism, an exhaust heat recovery circuit for recovering heat discharged from the fuel cell as hot water, a sealed hot water storage tank for storing the hot water recovered by the exhaust heat recovery circuit, and water supply connected to the hot water storage tank. In a fuel cell cogeneration system including a water supply pipe with a check valve, a pure water supply pipe connected to the water treatment mechanism to supply pure water, and a water supply mechanism connected to the water treatment mechanism. A drain pipe for discharging the concentrated water after the water treatment, a relief pipe connected to the water supply pipe or the hot water storage tank to release the water in the hot water storage tank to the outside, and a release pipe provided in the release pipe for the hot water storage tank. Pressure And a pressure regulating valve that opens when exceeding the pressure, constitute a downstream portion than the pressure adjusting valve of the relief pipe connected to the water supply pipe for the water purification.

According to a second aspect of the present invention, there is provided a polymer electrolyte fuel cell, a humidifying mechanism for humidifying a polymer membrane of the polymer electrolyte fuel cell, and A water treatment mechanism for purifying water to be supplied to the humidifying mechanism, an exhaust heat recovery circuit for recovering heat discharged from the fuel cell as hot water, and a sealed type storing hot water recovered by the exhaust heat recovery circuit. In a fuel cell cogeneration system including a hot water storage tank and a water supply pipe with a check valve connected to the hot water storage tank for supplying water, water in the hot water storage tank connected to the water supply pipe or the hot water storage tank is externally supplied. A relief pipe connected to the water treatment mechanism, a drain pipe for discharging the concentrated water after water treatment is connected to the water treatment mechanism, and the pressure in the hot water storage tank is set to the drain pipe. The configuring is provided the pressure regulating valve that opens when exceeding.

According to a third aspect of the present invention, there is provided a polymer electrolyte fuel cell, a humidifying mechanism for humidifying a polymer membrane of the polymer electrolyte fuel cell, A water treatment mechanism for purifying water to be supplied to the humidifying mechanism, an exhaust heat recovery circuit for recovering heat discharged from the fuel cell as hot water, and a sealed type storing hot water recovered by the exhaust heat recovery circuit. In a fuel cell cogeneration system including a hot water storage tank and a water supply pipe with a check valve connected to the hot water storage tank and supplying water, a portion of the water supply pipe downstream of the check valve, the water treatment mechanism, Connected via a water supply pipe for pure water purification, the water treatment mechanism, a heat exchanger for hot water recovery constituting the exhaust heat recovery circuit,
Alternatively, the fuel cell is connected via a pipe, the pure water supply pipe, the water treatment mechanism, and the pipe are also configured as a part of the exhaust heat recovery circuit, and the pipe or the pipe is used. A drainage pipe is connected to the pure water supply pipe, and the drainage pipe is provided with a pressure regulating valve that opens when the pressure in the hot water storage tank exceeds a set pressure.

[0012]

According to the construction of the fuel cell cogeneration system of the first aspect of the present invention, the water discharged through the relief pipe flows to the pure water supply pipe and is used as the pure water for the water treatment mechanism. I do.

Further, according to the configuration of the fuel cell cogeneration system of the present invention, when the pressure in the hot water storage tank exceeds the set pressure, the pressure provided in the drain pipe connected to the water treatment mechanism is increased. The regulator is also opened to discharge the concentrate, and the water discharged through the relief pipe is passed to the water treatment mechanism, and used as pure water for the water treatment mechanism.

Further, according to the configuration of the fuel cell cogeneration system according to the third aspect of the present invention, the water supply pipe for purifying water, the water treatment mechanism, and the pipe are also used as part of the exhaust heat recovery circuit, and the exhaust water is recovered. The water to be supplied for heat recovery is supplied as water for purification to the water treatment mechanism, the water for purification is constantly supplied to the water treatment mechanism, and the pressure in the hot water storage tank is increased to the set pressure. When the pressure exceeds the limit, the pressure control valve provided in the pipe or the drainage pipe connected to the water supply pipe for pure water is opened to drain water, and the water that has been discharged through the conventional relief pipe flows to the water treatment mechanism, and the water is treated. It is used as pure water for the mechanism.

[0015]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a system configuration diagram showing a first embodiment of a fuel cell cogeneration system according to the present invention.
Indicates closed-type hot water storage tanks.

The fuel cell 1 is provided with a humidifying mechanism 3 for humidifying the polymer membrane and a water treatment mechanism 4 such as an ion exchange membrane for purifying water supplied to the humidifying mechanism 3.
The water treatment mechanism 4 includes a water supply pipe 6 for pure water provided with a first pump 5 for supplying water for pure water, and a drain pipe 7 for discharging water concentrated with the water treatment. The drainage pipe 7 is connected with an on-off valve 8.

The fuel cell 1 and the hot water tank 2
A hot water supply for supplying the obtained hot water to an upper portion of the hot water storage tank 2 is connected to an exhaust heat recovery water supply pipe 10 provided with a second pump 9 and capable of taking out water from the bottom side of the hot water storage tank 2. A pipe 11 is connected, and an exhaust heat recovery circuit 12 is configured to collect exhaust heat from the fuel cell 1 as hot water and store the collected hot water in the hot water storage tank 2. The heat exhausted from the fuel cell 1 includes exhaust heat of reformer exhaust gas, exhaust heat of off-gas, and exhaust heat of cooling water, and at least one of them is recovered.

At the upper part of the hot water storage tank 2, a cooking place, a bathtub,
A hot water supply pipe 13 for supplying hot water to a washroom or the like is connected, and a water supply pipe 14 for replenishing water reduced by the hot water supply is connected to the bottom of the hot water storage tank 2.
A check valve 15 that opens as the pressure (for example, 0.2 Mpa) decreases above a set value is interposed.

A relief pipe 16 is connected between the check valve 15 of the water supply pipe 14 and the hot water storage tank 2, and is connected to the relief pipe 1.
6, a set pressure higher than the pressure of the check valve 15 (for example,
A pressure regulating valve 17 that opens at 0.3 Mpa) is interposed, and a portion of the relief pipe 16 downstream of the pressure regulating valve 17 is connected to the water supply pipe 6 for pure water purification. Thereby, when the volume expands due to the temperature change of the water due to the exhaust heat recovery and the pressure in the hot water storage tank 2 increases, the water is released from the hot water storage tank 2 through the pipe 15 and discharged therefrom. Is prevented, and the water can be used as pure water.

FIG. 2 is a system configuration diagram showing a second embodiment of the fuel cell cogeneration system according to the present invention. The difference from the first embodiment is as follows.
That is, the relief pipe 16 is connected to the water treatment mechanism 4,
The drain pipe 7 has a check valve 15 instead of the on-off valve 8 of the first embodiment.
A pressure regulating valve 21 that opens at a set pressure (for example, 0.3 Mpa) higher than the pressure of. The other configuration is the same as that of the first embodiment, and the description thereof will be omitted by retaining the same reference numerals.

With the configuration of the second embodiment, when the pressure in the hot water storage tank 2 exceeds the set pressure, the pressure regulating valve 21
Is also opened to discharge the concentrate, and the water discharged through the relief pipe 16 flows to the water treatment mechanism 4 so that the water can be used as pure water for the water treatment mechanism 4.

FIG. 3 is a system configuration diagram showing a third embodiment of the fuel cell cogeneration system according to the present invention. The difference from the second embodiment is as follows.
That is, the portion of the water supply pipe 14 downstream of the check valve 15 and the water treatment mechanism 4 are connected via the pure water supply pipe 6 with the pump 31 interposed therebetween, and the water treatment mechanism 4 and the exhaust heat The fuel cell 1 constituting the recovery circuit 12 is connected via a pipe 32, and the water purification pipe 6 for water purification, the water treatment mechanism 4, and the pipe 32 also serve as a part of the exhaust heat recovery circuit 12. .

A drain pipe 33 is connected to the pipe 32, and a pressure regulating valve 34 that opens at a set pressure (for example, 0.3 MPa) higher than the pressure of the check valve 15 is interposed in the drain pipe 33. The other configuration is the same as that of the second embodiment, and the description thereof will be omitted by retaining the same reference numerals.

According to the configuration of the third embodiment, water for pure water supply is always supplied to the water treatment mechanism 4, and when the pressure in the hot water storage tank 2 exceeds the set pressure, the pressure regulating valve 34 is provided. Is opened and drained, and the water discharged through the conventional relief pipe flows to the water treatment mechanism 4 and can be used as pure water for the water treatment mechanism 4. In the third embodiment, the exhaust heat recovery circuit 12 is configured to interpose a refrigerant circuit or the like in the middle and obtain hot water with a hot water recovery heat exchanger (not shown) as described later. In this case, the pipe 32 may be connected to the hot water recovery heat exchanger. Further, a drain pipe 32 provided with a pressure regulating valve 33 interposed therebetween.
May be connected to the pure water supply pipe 6.

FIG. 4 is a system configuration diagram showing a fourth embodiment of the fuel cell cogeneration system according to the present invention. The difference from the first embodiment is as follows.
In other words, the hot water recovery heat exchanger 42 is interposed in the refrigerant circuit 41 extending to the fuel cell 1, and the exhaust heat recovery water supply pipe 10 and the hot water supply pipe 11 are connected to the hot water recovery heat exchanger 42 so as to be discharged. A heat recovery circuit 12 is configured. The other configuration is the same as that of the first embodiment, and the description thereof will be omitted by retaining the same reference numerals.

In the first, second and fourth embodiments, the exhaust heat recovery water supply pipe 10 is connected to the water supply pipe 14, but may be connected to the lower part of the hot water storage tank 2. .
Also, the relief pipe 15 may be configured to be connected to the lower side of the hot water storage tank 2.

[0027]

As is apparent from the above description, according to the fuel cell cogeneration system of the first aspect of the present invention, the water discharged through the relief pipe is used as pure water for the water treatment mechanism. Therefore, wasteful drainage can be avoided, and the economic efficiency can be improved.

Further, according to the fuel cell cogeneration system of the second aspect of the present invention, the water discharged through the relief pipe is used as pure water for the water treatment mechanism, and is used for discharging the concentrate. The drainage pipe is connected to the water treatment mechanism, and the drainage pipe connected to the water treatment mechanism is provided with a pressure regulating valve. A pump can be dispensed with and an on-off valve is not provided in the drain pipe, so that the piping and equipment configuration can be simplified and the economic efficiency can be further improved.

According to the fuel cell cogeneration system of the third aspect of the present invention, the water supply pipe for purifying water, the water treatment mechanism, and the pipe are also used as a part of the exhaust heat recovery circuit. The water that has been discharged through the effluent piping flows into the water treatment mechanism and is used as water for purification for the water treatment mechanism. The accumulation of water is eliminated, and wastewater for discharging the concentrate is not required, so that wastewater can be avoided.
In addition, as described above, since it is also configured as a part of the exhaust heat recovery circuit, a water supply pipe and a pump for the water treatment mechanism can be made unnecessary and a drain pipe is not required, and further, an on-off valve is not provided in the drain pipe. In addition, it is possible to further simplify the piping configuration in addition to the device configuration, and to further improve the economic efficiency.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing a first embodiment of a fuel cell cogeneration system according to the present invention.

FIG. 2 is a system configuration diagram of a second embodiment.

FIG. 3 is a system configuration diagram of a third embodiment.

FIG. 4 is a system configuration diagram of a fourth embodiment.

FIG. 5 is a system configuration diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fuel cell 2 ... Hot water storage tank 3 ... Humidification mechanism 4 ... Water treatment mechanism 6 ... Water supply pipe for purification water 7 ... Drain pipe 12 ... Exhaust heat recovery circuit 14 ... Water supply pipe 15 ... Check valve 16 ... Release pipe 17, 21, 33 ... Pressure regulating valve 32 ... Piping

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Seisaku Higashiguchi 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi F-term in Osaka Gas Co., Ltd. (reference) 5H026 AA06 5H027 AA06 DD06 KK01

Claims (3)

[Claims] 1. A polymer electrolyte fuel cell, a humidifying mechanism for humidifying a polymer membrane of the polymer electrolyte fuel cell, a water treatment mechanism for purifying water supplied to the humidifying mechanism, and the fuel An exhaust heat recovery circuit for recovering heat discharged from the battery as hot water; a closed hot water storage tank for storing the hot water recovered by the exhaust heat recovery circuit; and a water supply with a check valve connected to the hot water storage tank for supplying water. A fuel cell cogeneration system comprising: a pipe; a pure water supply pipe connected to the water treatment mechanism to supply water for pure water; and a concentration after water treatment connected to the water treatment mechanism. A drain pipe for discharging water; a relief pipe connected to the water supply pipe or the hot water storage tank to release water in the hot water storage tank to the outside; and a pressure in the hot water storage tank provided in the release pipe, wherein a pressure in the hot water storage tank is equal to a set pressure. When it exceeds A pressure regulating valve that opens when the fuel cell is released, wherein a portion of the relief pipe downstream of the pressure regulating valve is connected to the pure water supply pipe. 2. A polymer electrolyte fuel cell; a humidifying mechanism for humidifying a polymer membrane of the polymer electrolyte fuel cell; a water treatment mechanism for purifying water supplied to the humidifying mechanism; An exhaust heat recovery circuit for recovering heat discharged from the battery as hot water; a closed hot water storage tank for storing the hot water recovered by the exhaust heat recovery circuit; and a water supply with a check valve connected to the hot water storage tank for supplying water. In a fuel cell cogeneration system comprising a pipe, a relief pipe connected to the water supply pipe or the hot water storage tank and allowing water in the hot water storage tank to escape to the outside is connected to the water treatment mechanism, and the water treatment mechanism is connected to the water treatment mechanism. A drain pipe for discharging the concentrated water after the water treatment is connected, and, to the drain pipe,
A fuel cell cogeneration system, comprising a pressure regulating valve that opens when the pressure in the hot water storage tank exceeds a set pressure. 3. A polymer electrolyte fuel cell; a humidifying mechanism for humidifying a polymer membrane of the polymer electrolyte fuel cell; a water treatment mechanism for purifying water supplied to the humidifying mechanism; An exhaust heat recovery circuit for recovering heat discharged from the battery as hot water; a closed hot water storage tank for storing the hot water recovered by the exhaust heat recovery circuit; and a water supply with a check valve connected to the hot water storage tank for supplying water. In a fuel cell cogeneration system including a pipe, a portion of the water supply pipe downstream of the check valve and the water treatment mechanism are connected via a pure water supply water pipe, and the water treatment mechanism is connected to the water treatment mechanism. Connecting the hot water recovery heat exchanger constituting the waste heat recovery circuit, or the fuel cell via a pipe, and connecting the pure water feed pipe, the water treatment mechanism, and the pipe to the waste heat. Also used as part of the recovery circuit And, a drainage pipe is connected to the pipe or the pure water supply pipe, and the drainage pipe is provided with a pressure regulating valve that opens when the pressure in the hot water storage tank exceeds a set pressure. Fuel cell cogeneration system.