JPH04337251A - Exhaust heat recovering device for fuel cell power generating facility - Google Patents

Abstract

PURPOSE:To maintain the balance between the heat input and heat output of a fuel cell power generating facility main body when the cold is reduced and perform a stationary operation without providing a separate cooling tower from a cooling tower on an absorption type refrigerator side. CONSTITUTION:A fuel cell power generating facility converting the heat energy obtained from the operating fluid in a fuel cell power plant 1 guiding the fuel gas containing hydrogen to an anode electrode and the air to a cathode electrode for power generation into the cold via an absorption type refrigerator 2 and feeding it to a cold load 5 is provided. This exhaust heat recovering device has a cooling tower 7 radiating the exhaust heat absorbed into the absorption type refrigerator 2 when the cold is utilized into the atmosphere and a heat exchanger 9 provided on the heat medium passage of the cooling tower 7 and applying the excess heat energy equivalent to the cold contained in the operating fluid in the plant 1 to the heat medium 10 of the cooling tower 7 to discharge it to the outside.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust heat recovery device for fuel cell power generation equipment.

0002

2. Description of the Related Art A conventional exhaust heat recovery device for fuel cell power generation equipment has a configuration as shown in FIG. In FIG. 3, 1 is a fuel gas containing hydrogen to an anode electrode;
A fuel cell power generation plant 2 generates electricity by introducing air into the cathode electrode, and the high temperature exhaust heat steam 3 recovered in this fuel cell power generation plant is supplied via a flow control valve 4 having a three-way valve, and the thermal energy is 5 is a cold load to which the cold heat 6 converted by the absorption refrigerator 2 is supplied. In addition, 7 is a cooling tower that absorbs waste heat generated when thermal energy is converted into cold heat by the absorption chiller 2 and radiates it to the atmosphere; 8 is the absorption chiller 2;
Fuel cell power generation plant 1 when the supply of cold heat is reduced due to
A part of the high-temperature exhaust heat steam 3 flowing out is transferred to the flow rate control valve 4.
This is a separate cooling tower that dissipates the heat energy into the atmosphere.

[0003] In the exhaust heat recovery device of the fuel cell power generation equipment having such a configuration, when using cold energy, the absorption chiller 2 is operated to convert the thermal energy of the high temperature exhaust heat steam 3 recovered in the fuel cell power generation plant 1 into cold energy. 6 and is supplied to the cooling load 5. In this case, the waste heat generated when the absorption chiller 2 converts thermal energy into cold energy is dissipated into the atmosphere from the cooling tower 7.

[0004] Furthermore, when the cold load 5 is reduced, for the purpose of balancing the heat balance of the fuel cell power generation plant 1,
High-temperature waste heat steam 3 corresponding to the difference between the recovered waste heat and the actual usage at the time of rated cold demand is introduced into a separate cooling tower 8 via a flow rate control valve 4, and its thermal energy is transferred to the atmosphere. is dissipated to.

[0005] Here, the amount of exhaust heat recovered from the fuel cell power generation plant 1 is Q, and the coefficient of performance (C
OP) is set to 1.2, the separate cooling tower 8 is Q
equipment with a capacity of In addition, as the absorption chiller 2, Q
In order to convert the thermal energy of 6 to cold energy, (1+CO
A cooling tower with a capacity of P)×Q=2.2Q is required.

Therefore, when using cold energy, if the cooling tower 7 with a capacity of 2.2 Q in the absorption chiller 2 is operated while the separate cooling tower 8 with a capacity of Q is stopped, and the demand for cold energy is reduced. In this case, the cooling tower 7 with a capacity of 2.2 Q in the absorption chiller 2 is in partial operation, and the separate cooling tower 8 with a capacity of Q is operated.

[0007]

[Problems to be Solved by the Invention] In this way, in the conventional exhaust heat recovery device of a fuel cell power generation plant, in addition to the cooling tower included in the absorption chiller, as mentioned above, the In order to balance the heat balance of the fuel cell power generation equipment itself, a cooling tower was installed and used to release heat energy equivalent to cold heat into the atmosphere.

[0008] For this reason, cooling towers that use the atmosphere as a low-temperature side fluid tend to be larger in size as equipment, and the installation of such cooling towers poses a problem in that the area occupied by the plant increases.

[0009] The present invention makes it possible to balance the heat balance of the fuel cell power generation equipment main body when cold heat is reduced without providing a cooling tower separate from the cooling tower on the absorption chiller side. An object of the present invention is to provide an exhaust heat recovery device for a fuel cell power generation facility that can reduce the installation area of a plant.

0010

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention supplies a hydrogen-containing fuel gas to an anode electrode.
Exhaust heat recovery for fuel cell power generation equipment that generates power by introducing air to the cathode electrode. Heat energy obtained from the working fluid in the fuel cell power generation plant is converted into cold energy by an absorption chiller and can be supplied to the cold load. The apparatus includes a cooling device that dissipates the exhaust heat absorbed by the absorption chiller to the outside when using cold energy, and a cooling device that is installed in a heat medium flow path of the cooling device to dissipate the cold energy that is contained in the working fluid in the plant when the cold load is reduced. and a heat exchanger that provides a considerable amount of surplus thermal energy to the heat medium of the cooling device and releases it to the outside.

[0011]

[Function] In the exhaust heat recovery device for fuel cell power generation equipment with such a configuration, when the cold load is reduced, the excess heat energy corresponding to the cold heat in the working fluid in the plant is transferred to the cooling equipment by the heat exchanger. By applying the heat to the heat medium and discharging it to the outside, it becomes possible to balance the heat balance of the fuel cell power generation equipment main body.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of an exhaust heat recovery device for a fuel cell power generation facility according to the present invention. The same parts as in FIG. I will only describe it.

In this embodiment, as shown in FIG.
A heat exchanger 9 is provided so as to be able to exchange heat with the heat medium 10 of
A part of the high-temperature exhaust heat steam 3 flowing into
1 and returned to the fuel cell power generation plant 1. Further, the temperature of the mixed hot water 13 of the return hot water 12 from the heat exchanger 9 and the return hot water 11 from the absorption chiller 2 is measured by the temperature measuring device 14, and this measured value is sent to the controller 1.
5, the opening degree of the three-way valve of the flow rate regulating valve 4 can be controlled.

[0015] Here, the absorption refrigerator 2 has a configuration as shown in FIG. As shown in FIG. 2, a regenerator 16 into which high-temperature waste heat steam 3 flows from the fuel cell power generation plant 1, a condenser 17 and an absorber 18 into which the heat medium 10 of the cooling tower 7 flows, and evaporator 19 to be replaced.

Next, the operation of the exhaust heat recovery device for the fuel cell power generation equipment constructed as described above will be described. When using cold energy, the thermal energy of the high-temperature waste heat steam 3 extracted from the fuel cell power generation plant 1 is converted into cold energy 6 in the absorption chiller 2.
and is supplied to the cooling load 5. In this case, the heat energy of the high-temperature waste heat steam 4 is converted into cold heat 6 via the absorption chiller 2, and then returned to the fuel cell power generation plant 1 as return hot water 11.

When the demand for cold heat 6 decreases in such a state, a portion of the high temperature waste heat steam 3 flows through the flow rate control valve 4.
The flow path is changed by , and it flows into the heat exchanger 9 . The high-temperature waste heat steam 3 that has flowed into the heat exchanger 9 has its heat removed by the heat medium 10 cooled using the cooling tower 7 and is returned to the fuel cell power generation plant 1 .

At this time, the return hot water 12 from the heat exchanger 9
Mixed hot water 13 with return hot water 11 from the absorption chiller 2
The temperature is measured by a temperature measuring device 14 such as a thermocouple, and the measurement signal is input to the controller 15. This controller 15
Now, the three-way valve opening degree of the flow control valve 4 is determined based on the measurement signal from the temperature measuring device 14, and the flow control valve 4 is controlled. As a result, the flow rate distribution between the high-temperature waste heat steam 3 flowing into the heat exchanger 9 and the flow rate flowing into the absorption refrigerator 2 changes, and the dissipation of the high-temperature waste heat steam 3 through the heat exchanger 9 is controlled. Here, the capacity required for the cooling tower 7 and the heat exchanger 9 to dissipate thermal energy to the atmosphere will be considered.

Assuming that the coefficient of performance (COP) of the absorption chiller 2 is 1.2, the capacity required for exhaust heat recovery when using cold energy is determined by If the thermal energy received by the internal working fluid of the absorption refrigerator 2 from heat is Q, then the cold heat 4 taken out from the evaporator 19 is Q×COP=1.2Q. Therefore,
The amount of heat exchanged in the condenser 17 is Q+1.2 Q=2.2
Therefore, the capacity of the cooling tower 7 is also required to be 2.2 Q.

When the demand for cold energy decreases to zero, the thermal energy of the high-temperature waste heat 4 that was taken away by the regenerator 16 is exchanged for the purpose of balancing the heat balance of the fuel cell power generation plant 1. However, in this case, since the absorption chiller 2 is not working, the refrigerant 10 only passes through the condenser 17 and absorber 18 of the absorption chiller 2, and no heat exchange occurs. Therefore, it is sufficient that both the heat exchanger 9 and the cooling tower 7 have a capacity of Q.

Therefore, in addition to the cooling tower 7 having a capacity of 2.2 Q which is required for operation of the absorption chiller when utilizing cold energy, there is a heat transfer capacity Q in the flow path of the refrigerant 10 circulating through the cooling tower 7. By installing the heat exchanger 9, it is possible to maintain the heat balance of the fuel cell power generation plant 1 regardless of the state of use of cold energy, and the steady operation of the plant can be continued.

[0022]

[Effects of the Invention] As described above, according to the present invention, there is no need to provide a cooling tower separate from the cooling tower on the absorption chiller side.
An exhaust heat recovery device for fuel cell power generation equipment that enables steady operation by balancing the heat balance of the fuel cell power generation equipment itself when cold heat decreases, thereby reducing the installation area of the plant. can be provided.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of an exhaust heat recovery device for a fuel cell power generation facility according to the present invention.

FIG. 2 is an internal configuration diagram of an absorption refrigerator in the same embodiment.

FIG. 3 is a system configuration diagram showing an exhaust heat recovery device of a conventional fuel cell power generation facility.

[Explanation of symbols]

1...Fuel cell power generation plant, 2...Absorption chiller, 3
. . . High temperature exhaust heat steam, 4 . . . Flow rate control valve, 5 . . . Cold load, 7 .

Claims (1)

[Claims] Claim 1: Thermal energy obtained from the working fluid in a fuel cell power generation plant that generates electricity by introducing hydrogen-containing fuel gas to the anode electrode and air to the cathode electrode is converted into cold energy by an absorption refrigerator. A waste heat recovery device for a fuel cell power generation facility that can supply cold energy to a cold load includes a cooling device that dissipates the waste heat absorbed by the absorption chiller to the outside when cold energy is used, and a heat medium flow path of this cooling device. and a heat exchanger that is provided and supplies a surplus of thermal energy corresponding to the cold heat of the working fluid in the plant to the heat medium of the cooling equipment and releases it to the outside when the cold load is reduced. Exhaust heat recovery device for fuel cell power generation equipment.