JPS60225364A - Fuel cell system unit with heat exhaust and moisture collection unit - Google Patents

Abstract

PURPOSE:To increase the amount of heat and moisture collection by guiding exhaust gas in a heat exhaust and moisture collection unit, generating water vapor from an evaporation cooling device provided in the said unit, and connecting it to the ejector of a fuel supply system through piping. CONSTITUTION:The exhaust gas from the oxygen electrode 1b of a fuel cell 1 and the combustion section 2b of a reformer 2 is guided to a heat exhaust and moisture collection unit 20 and the route of generated water vapor is connected to an ejector 4 that mixes the fuel with the water vapor through piping 34. Then, the exhaust gas is led from the entrance 29 of the unit 20 and subjected to heat-exchange by a cooling pipe 27. The gas is cooled by an evaporation cooling device 22 and the moisture is changed into condensed water. Water vapor is obtained by sucking the condensed water by a spraying pipe 24 and spraying it from a narrow hole 24a. As a result, the heat output that is taken out by the cooling pipe 27 in form of hot water can be reduced and the heat output that is taken out from the heat exchanger 7 for cooling water of a battery cooling system 1c in form of hot water can be increased. Consequently, thermal efficiency can be improved.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a fuel cell system equipped with an exhaust heat/moisture recovery device, and in particular a fuel cell system that is capable of adjusting heat output, has high thermal efficiency, and has a moisture recovery function. The present invention relates to a fuel cell system equipped with an exhaust heat/moisture recovery device suitable for increasing the amount of waste heat.

[Background of the invention]

First, a conventional fuel cell system will be explained with reference to FIG.

Fig. 1 is a system diagram of a conventional fuel cell system, in which the thick solid line arrows are natural gas and reaction gas paths, the dashed-dotted arrows are air paths, the two-dot chain arrows are exhaust gas paths, and the broken lines are water vapor paths. Thin solid line arrows each indicate the path of the cooling water.

In FIG. 1, 1 is a fuel cell main body, which includes a hydrogen electrode la, an oxygen electrode 1b, and a battery cooling device IC.

Reference numeral 2 denotes a refoamer, which consists of a reaction section 2a and a combustion section 2b. 3 is a shift converter, and 4 is an ejector that functions as a fuel mixing means, and these constitute a fuel supply system for the fuel cell 1.

12 is a blower provided in the air supply system.

5 is a steam generator, 6 is an inverter that converts direct current to alternating current, 7 is a cooling water heat exchanger, 8 is an exhaust gas heat exchanger, 9 is a water tank, and 10 is a cooling pump.

11 is a water supply pump.

Heat exchanger for exhaust gas8. The water tank 9 constitutes an exhaust gas and water recovery system, and the water tank 9. Water supply pump 11, battery cooling device 1c, steam generator 5. Cooling water heat exchanger7. The cooling pump 10 constitutes a battery cooling system.

The operation of the fuel cell system having such a configuration will be explained.

Fuel such as natural gas is mixed with water vapor in the ejector 4,
It is supplied to the reaction section of the reformer 2, where it is reformed into a gas containing a large amount of hydrogen. The gas is then led to the shift converter 3, where the carbon monoxide in the gas reacts with wood and is converted into carbon dioxide and hydrogen.

Next, if there is excess moisture in the gas, after removing it, it is guided to the hydrogen electrode 1a of the fuel cell main body 1, where about 80% of the hydrogen is consumed, and the hydrogen electrode containing the remaining 20% hydrogen. The exhaust gas is returned to the combustion section 2b of the reformer 2 and is used as part of the combustion heat required for the reforming reaction.

The air is pressurized by the blower 12 and is supplied to the oxygen electrode 1b of the fuel cell main body 1 and the combustion section 2b of the reformer 2.

The exhaust gas from the oxygen electrode 1b of the fuel cell main body 1 and the exhaust gas from the combustion part 2b of the re-former 2 are combined and guided to the exhaust gas heat exchanger 8 as shown by the double-dashed arrow, where the exhaust gas is heated by circulating water or the like. Exhaust heat recovery and moisture recovery are performed by cooling until moisture condenses. The collected moisture is led to the water tank 9 and reused.

The cooling water is pressurized by the cooling water pump lO, is supplied to the cell cooling device dle of the fuel cell main body 1, and is flushed by the steam generator 5 after removing the generated heat from the fuel cell main body 1. Here, a part of the cooling water becomes water vapor, and the flow rate is adjusted by the steam control valve 13 as shown by the broken line arrow, and the water vapor is guided to the ejector 4. It joins with the makeup water shown by the thin solid line arrow from the remaining cooling water supply pump 11, and is led to the cooling water pump IO again. Excess heat generated in the battery cooling system is recovered in the form of hot water or the like by the cooling water heat exchanger 7.

In such conventional fuel cell system devices, exhaust heat from the device is recovered in the form of hot water etc. by the exhaust gas heat exchanger 8 and the cooling water heat exchanger 7, and this is used as heat from the fuel cell system. This is the output.

Generally, when adjusting the balance of heat and substances in a fuel cell system so that there is no excess or deficiency of water, the heat output from the two heat exchangers described above is: S for water vapor and S for carbon in the fuel. C, the output ratio of water vapor S cannot be easily changed unless the ratio of water vapor S to carbon C of fuel, ie, the water vapor ratio S/C, is changed. This means that it is difficult to deal with the external heat load without excess or deficiency.

In addition, the temperature level of the heat output from the exhaust gas heat exchanger 8 (about 50 to 60 degrees Celsius) is generally lower than the temperature level of the cooling water heat exchanger 7 (maximum about 170 to 180 degrees Celsius). The disadvantage was that it was difficult to use.

On the other hand, the exhaust gas heat exchanger 8 has the disadvantage that it is not easy to cool it to a sufficiently low temperature (about 50° C.) because it is cooled by circulating water or the like.

[Purpose of the invention]

The present invention was made in order to solve the above-mentioned issue of sideways, and it is possible to adjust the heat output, increase the heat output at high temperature level, have high thermal efficiency, and recover waste heat with a large amount of moisture.・The purpose is to provide a fuel cell system equipped with a water recovery device.

[Summary of the invention]

The configuration of a fuel cell system equipped with an exhaust heat/moisture recovery device according to the present invention includes a fuel cell main body, a fuel supply system for the fuel cell main body, an air supply system, a battery cooling system, an exhaust gas/moisture recovery system, and accessories. In a fuel cell system equipped with an exhaust heat/moisture recovery device consisting of a device, the exhaust gas/moisture recovery system is provided with an exhaust heat/moisture recovery device, and the above-mentioned fuel supply system is installed in the exhaust heat/moisture recovery device. , conduct the exhaust gas generated from the air supply system and the fuel cell main body, generate water vapor by an evaporative cooler provided in the exhaust heat/moisture recovery device, and arrange a distribution pipe for this water vapor in the fuel supply system. It is connected to the ejector that is installed.

It should be noted that in the present invention, the conventional exhaust gas heat exchange system is replaced with an exhaust heat/moisture recovery device operated by an ejector.

The principle is to reduce the pressure of saturated condensed water using an ejector in this exhaust heat/moisture recovery device, and to cool it by removing the heat of vaporization from the surrounding exhaust gas.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 is a system diagram of a fuel cell system equipped with an exhaust heat/moisture recovery device according to an embodiment of the present invention, and FIG. 3 is a longitudinal sectional view of the exhaust heat/moisture recovery device section of FIG. 2. It is. In the figure, the same reference numerals as in FIG. 1 are the same as those in the prior art, so the explanation thereof will be omitted.

Further, the types of arrows are also the same as in FIG.

In FIG. 2, 20 indicates the exhaust heat/moisture recovery device 33 is a steam control valve, and 34 indicates the exhaust heat/moisture recovery device 20 and the ejector 4.
This is the steam piping that connects the

The exhaust gas from the oxygen electrode 1b of the fuel cell main body 1 and the exhaust gas from the combustion section 2b of the re-former 2 are combined as shown by the two-dot chain arrow and guided to the exhaust heat/moisture recovery device 20, where they are collected as cooling water and as will be explained next. It is sufficiently cooled by an evaporative cooler built into the equipment, and exhaust heat and moisture are recovered.

Next, in Fig. 3, 21 is an exhaust heat/moisture recovery device W20.
The casing 22 is an evaporative cooler installed inside the casing 21, and cooling fins 23 are provided on the outer periphery of the container to promote cooling.

24 is a spray pipe provided in the evaporative cooler 22;
The spray pipe 24 opens at the bottom of the evaporative cooler 22 to suck up condensed water that collects at the bottom of the casing.

27 is a cooling pipe through which cooling water to exchange heat with exhaust gas flows within the casing 21, 27a is a cooling water inlet, 27b
indicates the cooling water outlet. 28 is cooling'! A separator disposed below the cooling pipe 27 guides condensed water dripping from the cooling pipe 27 to the bottom of the casing 21.

Reference numeral 29 denotes an exhaust gas inlet through which exhaust gas from the combustion section 2b of the reflomer 2 and exhaust gas from the oxygen electrode 1b of the fuel cell body 1 related to the fuel supply system and the air supply system are conducted. 30 is an exhaust gas outlet, and 31 is a steam outlet for guiding steam generated in the evaporative cooler 22 to the ejector 4 via a steam pipe 34.

Next, the operation of the fuel cell system equipped with the exhaust heat/moisture recovery device configured as described above will be explained.

The exhaust gas flows in from the exhaust gas inlet 29 and is cooled by the evaporative cooler 22, and the moisture in the exhaust gas condenses to become condensed water, which is stored at the bottom of the casing 21.

Since the pressure inside the evaporative cooler 22 is lowered to below the exhaust gas pressure by the ejector 4 connected to the pipe 34, the condensed water is sucked up into the spray pipe 24 and flows through the pores provided in the spray pipe 24. It is sprayed from 24a.

The pressure of the condensed water before spraying is almost the same as the pressure of the exhaust gas, and during the spraying process, the pressure is reduced by isenthalpic change and becomes saturated water. In this state, it absorbs pressure death latent heat from its surroundings, and some of it turns into water vapor.

The generated water vapor is transferred from the water vapor outlet 31 to the water vapor pipe 34.
The flow is as shown by the broken line, and the flow rate is adjusted by the flow rate control valve 33 and is sucked into the ejector 4.

The liquid level inside the evaporative cooler 22 is controlled to a constant level by a float 26 for detecting the liquid level and a liquid level control valve 25 linked to the float 26.

As mentioned above, when water vapor is generated inside the evaporative cooler 22, heat of vaporization is taken away from the surroundings, which is nothing but cooling the exhaust gas.

After the exhaust gas is cooled in the evaporative cooler 22, it exchanges heat with cooling water in the cooling pipe 27 to extract the remaining heat, and is discharged from the exhaust gas outlet 30 from which the heat has been removed.

On the other hand, the cooling water flowing into the cooling pipe 27 from the cooling water inlet 27a absorbs heat from the exhaust gas and becomes hot water, and the cold water exit 27b
recovered from.

According to this embodiment, which includes such an exhaust heat/moisture recovery device 20, the following effects can be achieved.

1) After the temperature of the exhaust gas is lowered by the action of the evaporative cooler 22, heat exchange with the cooling water is performed in the cooling pipe 27, so the heat output taken out as hot water by the cooling pipe 27 can be reduced, and the , it is possible to increase the heat output taken out as hot water from the cooling water heat exchanger 7 of the battery cooling system.

That is, the ratio of heat output at a high temperature level to heat output at a low temperature level can be changed.

As explained in the prior art section, the temperature level of the cooling water heat exchanger 7 is higher than the temperature level of the cooling pipe 27 related to the exhaust gas heat exchanger, so according to this embodiment, the temperature level of the cooling water heat exchanger 7 is higher than the temperature level of the cooling pipe 27 related to the exhaust gas heat exchanger. The heat output of the level will increase.

2) By increasing the degree of vacuum by the ejector 4, the generation of steam in the steam cooler 22 is promoted, which cools the exhaust gas and takes away the heat of vaporization. can be cooled. Therefore, it is possible to increase the amount of heat recovery and the amount of water recovery, and the thermal efficiency can be increased.

〔Effect of the invention〕

As described above, according to the present invention, the heat output can be adjusted, the heat output at a high temperature level can be increased, the heat efficiency is high, and the waste heat/moisture recovery device is equipped with a large amount of moisture recovery. A fuel cell system device can be provided.

[Brief explanation of drawings]

Figure 1 is a system diagram of a conventional fuel cell system, and Figure 2 is a system diagram of a conventional fuel cell system.
FIG. 3 is a system diagram of a fuel cell system equipped with an exhaust heat/moisture recovery device according to an embodiment of the present invention, and is a longitudinal sectional view of the exhaust heat/moisture recovery device section of FIG. 2. 1...Fuel cell main body, la...hydrogen electrode, 1b...
Oxygen electrode, lc...Battery cooling device, 2...Reformer, 2a...Reaction section, 2b...Combustion section, 3...Shift converter, 4...Ejector, 7...Cooling water heat exchanger, 9... water tongue, 10... cooling water pump,
II...Water pump, 12...Blower, 20...
Exhaust heat/moisture recovery device, 22... Evaporative cooler, 23...
・Fin, 24...Spray tube. 27...Cooling pipe, 29...Exhaust gas inlet, 3o...
Exhaust gas outlet, 31... Steam outlet, 33... Steam control valve, 34... Steam piping. Agent Patent Attorney Akio Takahashi

Claims (1)

[Claims] 1. An exhaust heat/moisture recovery device comprising a fuel cell main body, a fuel supply system for the fuel cell main body, an air supply system, a battery cooling system, an exhaust gas and moisture recovery system, and ancillary devices. In the fuel cell system, an exhaust heat/moisture recovery device is provided in the exhaust gas/moisture recovery system, and the exhaust heat/moisture recovery device includes:
The exhaust gas generated from the above fuel supply system, air supply system, and fuel cell body is conducted, and water vapor is generated by the evaporative cooler installed in the waste heat/moisture recovery device; and this water vapor distribution piping. A fuel cell system device equipped with an exhaust heat/moisture recovery device, characterized in that the device is connected to an ejector disposed in the fuel supply system. 2. In the device described in claim 1, the evaporative cooler is provided with cooling fins on its outer periphery to cool the exhaust gas and produce condensed water, and the A fuel cell system equipped with an exhaust heat/moisture recovery device that is equipped with a spray pipe that can vaporize water under reduced pressure using an ejector.