JPH04306566A - Fuel cell plant cooling system - Google Patents

Abstract

PURPOSE:To enable extraneous matters to the ferrule of an insulating hose connected to inlet/outlet of a cooling plate to be removed easily in a cooling system to cool a fuel cell plant by supplying refrigerant liquid to a fuel cell body or discharging the refrigerant liquid from the fuel cell body. CONSTITUTION:A stop valve 17 is arranged in a supply pipe 12 to supply cooling water to a fuel cell body 11 through a water manifold 4A, and a stop valve 19 is arranged in a discharge pipe 18 to discharge the cooling water from the fuel cell body 11 through a water manifold 4B, and the upstream side of the stop valve 17 in the supply pipe 12 and the upstream side of the stop valve 19 in the discharge pipe 18 are connected to each other by means of a pipe 20 provided with a stop valve 21, and the downstream side of the stop valve 17 in the supply pipe 12 and the downstream side of the stop valve 19 in the discharge pipe 18 are connected to each other by means of a pipe 22 provided with a stop valve 23.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell plant, and more particularly to a cooling system for a fuel cell main body.

0002

2. Description of the Related Art A fuel cell is a device that oxidizes the chemical energy of fuel using an electrochemical process, thereby directly converting the energy released as a result of the oxidation reaction into electrical energy. This fuel cell power generation system has a thermal efficiency of 40-50 even on a relatively small scale.
%, and is expected to far exceed new thermal power generation. In addition, the emissions of SOx and NOx, which are pollution factors that have become a major social problem in recent years, are extremely low, the power generation device does not include a combustion cycle, so it does not require a large amount of cooling water, and the vibration is small. High conversion efficiency can be expected, there are few environmental problems such as noise and exhaust gas, and the characteristics include good responsiveness to load fluctuations, so there are expectations and interest in research into its development and practical application. has been received. As this type of power generation device, for example, Japanese Patent Application Laid-Open No. 60-93765 is known. That is, as shown in FIG. 2, the fuel cell main body has a large number of cells 2 for power generation in a fuel cell main body tank 1.
The cell 2 is composed of a stacked body of a cooling plate 3 for discharging heat generated in the cell 2, and a reactant gas supply/discharge manifold attached to the side of this stacked body.The cell 2 contains fuel gas, air, Cooling water as a refrigerant is supplied to the cooling plate 3 from the outside via a water manifold 4A, and the cooled water is discharged to the gas-liquid separator 5 via a water manifold 4B.

0003

[Problem to be Solved by the Invention] By the way, when a fuel cell is operated, each cooling plate 3 has a different potential, so the cooling pipes leading in and out of each cooling plate 3 must be electrically insulated from each other. Must be. As one method for this purpose, a structure is adopted in which an insulating hose 6 is used to connect the water manifold 4A and the cooling plate 3 and to connect the water manifold 4B and the cooling plate 3. The structure of this insulating hose 6 is shown in FIG. Since the cap 7 of the insulating hose 6, the water manifolds 4A, 4B, and the cooling pipe 8 are generally made of metal, one of the caps 7 at both ends of the insulating hose 6 is +, and the other is -.
voltage is applied.

[0004] Furthermore, the cooling water contains impurities such as minute amounts of metal ions and corrosion products dissolved from pipes, etc., and these impurities emit or accept electrons at the mouthpiece 7 of the insulating hose 6, causing metal or The metal oxide becomes a metal oxide and adheres to the cap 7 as a deposit 9, as shown in FIG. This deposit 9 then grows along the flow direction 10. When a fuel cell plant is operated for a long period of time, these deposits 9 may grow to a large extent, block the cap 7, and prevent the supply of cooling water to the cooling plate 3. In order to prevent this, conventionally, the operation had to be stopped periodically and the cooling system had to be cleaned with chemicals to remove the deposits 9.

The present invention has been made in view of the above-mentioned circumstances, and its object is to provide a fuel cell plant cooling system that allows deposits on the caps of insulating hoses to be removed by simple means. Our goal is to provide the following. [Structure of the invention]

[0006]

[Means for Solving the Problems] The present invention provides a structure in which cells and cooling plates are stacked and housed in a container, and the cooling plates of a fuel cell body configured to supply fuel gas and oxidant gas are each insulated. Supply piping and discharge piping are connected via hoses to allow refrigerant liquid to flow, and a portion of the flow rate of this refrigerant liquid boils to cool the fuel cell body, and the evaporated refrigerant is removed by a gas-liquid separator. In a fuel cell plant cooling system designed for recirculation, the supply pipe and the discharge pipe are connected by a pair of pipes each equipped with a valve, so that the inflow side and the discharge side of the refrigerant liquid into the fuel cell body can be reversed. This is what I did.

[0007]

[Function] In general, impurities present in the refrigerant liquid in the cooling pipe are deposited on the insulating hose in the flow direction (
It grows along the arrow 10 shown in FIG. Therefore, this deposit (indicated by reference numeral 9 in FIG. 4) is strong against the flow in the direction in which it has grown, but is brittle against the flow in the opposite direction. Therefore, by reversing the flow direction of the refrigerant liquid (in the opposite direction to the flow direction 10 in FIG. 4) through a pair of pipes each having a valve for the refrigerant liquid supply pipe and discharge pipe, the deposits can be removed. It can be peeled off relatively easily. Further, the present invention operates with a liquid single-phase flow at the inlet of the cooling plate and a two-phase flow with a quality of, for example, 3 to 30% at the outlet. At this time, the flow velocity at the inlet of the cooling plate is, for example,
In contrast, the flow velocity at the outlet is 5 to 20 m/s, about 10 times that at the inlet. For this reason,
There is a lot of deposits on the mouthpiece of the insulating hose on the inlet side of the cooling plate, but on the outlet side, high-speed steam and liquid flow alternately, so deposits are less likely to adhere to the mouthpiece. Therefore, by reversing the direction of flow to the cooling plate, the deposits adhering to the inlet side can be effectively peeled off by the high-speed two-phase flow.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the present invention. In the figure, reference numeral 11 indicates the fuel cell main body described above. Supply piping 1 connecting multiple water manifolds 4A that supply cooling water (pure water) to multiple fuel cell bodies 11, respectively
2, a filter 13, a cooler 14, a circulation pump 15, a regulating valve 16, and a stop valve 17 are connected in this order from the gas-liquid separator 5 side. Further, a stop valve 19 is connected in the middle of a discharge pipe 18 that connects a plurality of water manifolds 4B that discharge cooling water from a plurality of battery bodies 11, respectively. Thus, the supply pipe 12 is connected to the upstream side of the stop valve 19 of the discharge pipe 18 via the pipe 20 and the stop valve 21 on the upstream side of the stop valve 17, and the supply pipe 12 is connected to the upstream side of the stop valve 19 of the discharge pipe 18 on the downstream side of the stop valve 17. 2
3 to the downstream side of the stop valve 19 of the discharge pipe 18.

Next, the operation of the embodiment configured as above will be explained. First, during normal cooling, the gas-liquid separator 5
Cooling water supplied from the supply pipe 12 enters the supply pipe 12, has impurities removed by the filter 13, is cooled by the cooler 14, is pressurized by the circulation pump 15, has its flow rate adjusted by the regulating valve 16, and is passed through the stop valve 17. The water is supplied from each water manifold 4A to each fuel cell main body 11 through the water manifold 4A. After cooling the cells (indicated by reference numeral 2 in FIG. 3) via cooling plates (indicated by reference numeral 3 in FIG. 3) within each fuel cell main body 11, each water manifold 4B
It is discharged into the discharge pipe 18 and returns to the gas-liquid separator 5 through the stop valve 19. After the vapor is separated by the gas-liquid separator 5, it enters the supply pipe 12 again and repeats the circulation. The vapor separated by the gas-liquid separator 5 is discharged outside the gas-liquid separator 5. Note that the gas-liquid separator 5 is replenished with cooling water corresponding to the separated and discharged steam by appropriate means. Next, when removing the deposits 9 attached to the mouthpiece 7 of the insulating hose 6, after closing the stop valves 17 and 19 and opening the stop valves 21 and 23, the cooling water is turned into gas and liquid in the same manner as in the case of cooling described above. It flows from the separator 5 to the supply pipe 12. The cooling water passes through a filter 13 and a cooler 14, is pressurized by a circulation pump 15, and is then pressurized by a regulating valve 16.
The flow rate is adjusted from the upstream side of the stop valve 17 to the stop valve 21.
, flows through the pipe 20 and enters the upstream side of the stop valve 19 of the discharge pipe 18, and flows from each water manifold 4B to each fuel cell main body 11.
supplied to After the cells are cooled through the cooling plates in each fuel cell main body 11 in the same way as in the case of cooling described above, the cells are discharged from each manifold 4A to the supply pipe 12, and from the downstream side of the stop valve 17 to the pipe 22 and the stop valve 23. Flowing through the discharge pipe 18
The gas enters the downstream side of the stop valve 19 and returns to the gas-liquid separator 5. By causing the cooling water to flow backward in this way, the insulation hose 6
The deposits 9 that have grown on the mouthpiece 7 along the flow direction during normal cooling can be easily peeled off and removed by the filter 13. After the deposit 9 is removed, the stop valves 17, 19, 21, and 23 are opened and closed to return to the normal cooling state described above.

Therefore, with the above configuration, the direction of the cooling water flowing into the cooling plate of the battery body is reversed by opening and closing the four stop valves 17, 19, 21, 23, that is, before switching, the liquid The inlet side, which was a single-phase flow, becomes the outlet side of a two-phase flow of vapor and liquid, and this high-speed two-phase flow can easily remove deposits 9 that have grown on the mouthpiece 7 of the insulating hose 6 along the flow direction. . Further, deposits 9 and the like that have grown on the exit side before switching can also be removed. The deposits 9 peeled off by the backflow of cooling water are captured by the filter 13, so that they do not adversely affect the cooling system.

[0011] The present invention can also be applied to cases where other refrigerants such as water to which additives have been added in addition to pure water are used as the refrigerant liquid, and when the direction of flow into the fuel cell main body is changed during operation. Since it is necessary to perform the switching operation in a short time, the stop valves 17, 19, 21, and 23 may be electromagnetic valves, air-driven valves, three-way valves, or the like, and may also be switched by a timer. Of course, if you do not want to switch during operation, a manual valve will suffice.

0012

As explained above, according to the present invention, the refrigerant liquid supply piping and discharge piping are each provided with a valve, and the supply piping system and the discharge piping system are connected by a pair of piping each having a valve. To provide a cooling system for a fuel cell plant in which deposits adhering to the mouthpiece of an insulating hose in a fuel cell main body can be easily removed by simple means of opening and closing four valves. be able to.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a sectional view showing the internal structure of a fuel cell main body related to the present invention.

3 is a sectional view showing the structure of an insulating hose connected to a cooling plate of the fuel cell main body shown in FIG. 2. FIG.

FIG. 4 is an explanatory diagram showing a state in which impurities in the refrigerant liquid are attached to the insulated hose shown in FIG. 3;

[Explanation of symbols]

1... Fuel cell main tank, 2... Cell, 3... Cooling plate, 4A
, 4B... Water manifold, 5... Gas-liquid separator, 6... Insulating hose, 7... Cap, 9... Deposit, 10... Flow direction, 11...
Fuel cell main body, 12... Supply piping, 15... Circulation pump, 1
7, 19, 21, 23...stop valve, 18...discharge piping, 20
, 22...Piping.

Claims (1)

[Claims] 1. Cells and cooling plates are stacked and housed in a container, and supply pipes and A discharge pipe is connected to flow a refrigerant liquid, a part of the flow rate of this refrigerant liquid boils to cool the fuel cell body, and the evaporated refrigerant is removed by a gas-liquid separator and recirculated. In the fuel cell plant cooling system, the supply pipe and the discharge pipe are connected by a pair of pipes each having a valve, so that the inflow side and the discharge side of the refrigerant liquid into the fuel cell main body can be reversed. A fuel cell plant cooling system characterized by: