JP3718917B2 - Abnormality detection method for fuel cell power generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooling water or gas abnormality detection method used when operating a fuel cell power generator.
[0002]
[Prior art]
FIG. 2 is a schematic diagram showing a basic configuration of a fuel gas supply system, an air supply system, and a cooling water system of a conventional fuel cell power generator using a phosphoric acid type water-cooled fuel cell.
The fuel cell main body 1 schematically shown is configured by laminating a single cell formed by sandwiching an electrolyte layer holding phosphoric acid between a fuel electrode and an air electrode, and generates heat generated by power generation for each of the plurality of layers. A cooling plate to be removed is interposed. The fuel electrode of the fuel cell main body 1 is supplied with fuel gas having a high hydrogen concentration, which is desulfurized by a hydrodesulfurizer 4, mixed with water vapor by an ejector pump 3, and reformed by the fuel reformer 2. The That is, after introducing the raw fuel into the hydrodesulfurizer 4 and adding hydrogen to adsorb and remove sulfur contained in the raw fuel as an odorant, the steam sent from the steam separator 5 in the ejector pump 3 The fuel gas is mixed, sent to the fuel reformer 2 and heated to produce a fuel gas with a high hydrogen concentration by a catalytic reaction, which is supplied to the fuel electrode. The pipe for supplying the fuel gas to the fuel electrode is connected to a recycle gas circuit for recirculating and mixing a part of the fuel gas to the raw fuel introduced into the hydrodesulfurizer 4. Hydrogen contained in the circulated fuel gas is effectively used for desulfurization in the hydrodesulfurizer 4. Further, by introducing into the combustor of the fuel reformer 2 the fuel electrode off-gas containing residual hydrogen discharged without contributing to the reaction from the fuel electrode and the combustion air supplied from the outside by the blower, The flow gas of the reformer 2 is heated. On the other hand, reaction air is taken in and supplied to the air electrode of the fuel cell main body 1 by a blower. The air electrode off-gas discharged from the air electrode contains reaction product water generated by the electrochemical reaction, and the combustion exhaust gas discharged from the combustor of the fuel reformer 2 is generated by combustion. Contains combustion-generated water. Therefore, the air electrode off gas and the combustion exhaust gas are configured to be sent to the generated water recovery device 7 to recover the generated water and then discharged to the outside.
[0003]
Cooling water is supplied from the water vapor separator 5 to the cooling plate of the fuel cell main body to remove heat generated during power generation, and the temperature of the fuel cell main body is maintained at a predetermined operating temperature. The cooling water that has received heat and has reached a high temperature in the cooling plate is cooled by the cooling water cooler 6 and then returned to the water vapor separator 5 to be separated into water vapor and water. In addition, the heat obtained by cooling the cooling water cooler 6 is taken out and used effectively. The water vapor separated by the water vapor separator 5 is sent to the ejector pump 3 and used for reforming as described above. Further, in order to compensate for the amount of water that is reduced by the supply of water vapor to the ejector pump 3, the generated water recovered by the generated water recovery device 7 is purified and introduced by the water treatment device 8. Further, the steam separator 5 is provided with a blowdown circuit that blows down the stored water and sends it to the generated water recovery device 7, and sends the stored water from the blowdown circuit to the generated water recovery device 7. The water treatment device 8 is purified and returned to the water vapor separator 5 to prevent the water quality from deteriorating.
[0004]
[Problems to be solved by the invention]
In the fuel cell power generator of the configuration of FIG. 2, the blow-down circuit for blowing down the water stored in the water vapor separator 5 and the recycle gas circuit for recirculating a part of the fuel gas always meet the load during operation. There must be a flow of water or gas. Accordingly, a fixed restrictor (not shown) is incorporated in these circuits, thereby ensuring a flow rate.
[0005]
However, if the operation is continued for a long time, there is a risk that solids or precipitates contained in each fluid adhere to the fixed restrictor and the flow rate is reduced or the flow stops in the worst case. . If the flow rate of the blow-down circuit is insufficient, impurities in the cooling water circulation system are concentrated and the quality of the stored water in the water vapor separator 5 deteriorates, and the water vapor sent to the ejector pump 3 contains impurities, and the performance of the ejector pump 3 is reduced. Will result in a decline. In addition, when the flow rate of the recycle gas circuit is insufficient, the amount of hydrogen in the hydrodesulfurizer 4 is insufficient and the desulfurization performance is reduced, and sulfur leaks to the fuel reformer 2 to poison the reforming catalyst and reform. The performance will be reduced.
[0006]
Therefore, in the conventional fuel cell power generator, the flow meter 10 and the flow meter 9 are incorporated in each circuit, the flow rate is measured to detect a decrease in the flow rate, and measures are taken in advance so as not to cause the above situation. Is adopted.
However, when monitoring the flow rate with a flow meter and detecting anomalies in this way, using the method of periodically monitoring the flow meter is inefficient and labor intensive, and a signal with a built-in flow meter with an oscillator is used. If the control device is configured to monitor and the alarm signal is generated from the value, it is necessary to use an expensive flow meter, which increases the cost.
[0007]
An object of the present invention is to provide a fuel cell power generation apparatus abnormality detection method that can easily and inexpensively detect a decrease in the flow rate of a blow-down circuit or a recycle gas circuit by solving the problems of the prior art as described above. There is to do.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, (1) a fuel cell body having a cooling plate through which cooling water flows and a high-temperature cooling water discharged from the cooling plate are introduced. A steam separator for separating the steam into water and reforming the raw fuel into fuel gas and supplying the steam to a fuel reformer that supplies the fuel cell body and supplying the water to the cooling plate; And a product water recovery device that recovers the product water contained in the air electrode off-gas of the fuel cell main body and the combustion exhaust gas of the fuel reformer, and the product water recovered by the product water recovery device is purified by a water treatment device. In the method for detecting an abnormality of the fuel cell power generator introduced into the steam separator, the indicated value of the thermometer provided in the blow-down circuit for discharging the stored water inside the steam separator to the generated water recovery device is within a predetermined range. By leaving more And to detect an abnormality of the flow rate of blowdown.
[0009]
(2) In addition, desulfurizer that introduces raw fuel and adds sulfur to desulfurize sulfur, and high-temperature cooling water discharged from a cooling plate interposed in the fuel cell main body, Ejector pump that mixes water vapor from a water vapor separator that supplies water to the cooling plate after being separated into water and the desulfurized raw fuel, and a high hydrogen concentration by introducing the raw fuel mixed with water vapor A recycle gas circuit comprising a fuel reformer for reforming into fuel gas, mixing a part of the fuel gas obtained by the fuel reformer with the raw fuel introduced into the desulfurizer, and using the contained hydrogen for desulfurization In an abnormality detection method for a fuel cell power generation device comprising:
An abnormality detection method for a fuel cell power generation apparatus, wherein an abnormality in a flow rate of a recycle gas is detected when an indication value of a thermometer provided in the recycle gas circuit departs from a predetermined range.
[0010]
(3) Further, in (1) and (2) above, a heat dissipating means for promoting heat dissipating in the circuit is provided on the upstream side of the thermometer of the circuit provided with the thermometer, and the indicated value of the thermometer is predetermined. An abnormality in the flow rate is detected by moving away from the range.
If the flow rate of the blowdown water flowing in the blowdown circuit or the flow rate of the recycle gas flowing in the recycle gas circuit is normal, the thermometer incorporated in the circuit has a normal value, for example, a normal phosphoric acid type water cooled fuel cell. In fuel cell power generators, the temperature is 100 to 160 ° C. On the other hand, when the flow rate flowing through the circuit decreases due to some cause, the temperature at the temperature measurement point decreases due to the balance between the amount of heat of the fluid brought into the circuit and the amount of heat released from the wall surface of the circuit, and the indicated value of the thermometer decreases. It will be.
[0011]
Therefore, as described in (1) above, fluctuations in the flow rate of the recycle gas can be detected based on the indicated value of the thermometer, and an abnormality in the flow rate is determined depending on whether or not the indicated value of the thermometer deviates from a predetermined normal range. Can be detected. Further, if the above (2) is taken, it is possible to detect fluctuations in the flow rate of the blow-down water based on the indicated value of the thermometer, and an abnormal flow rate depends on whether or not the indicated value of the thermometer deviates from a predetermined normal range. Can be detected. Further, as in (3), the amount of heat radiation from the wall surface of the circuit is increased by the heat radiating means, so that the change in the balance when the flow rate decreases is increased, and the flow rate decrease is detected with higher sensitivity.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a basic configuration of a fuel gas supply system, an air supply system, and a cooling water system of a fuel cell power generation apparatus using a phosphoric acid type water-cooled fuel cell, showing an embodiment of a fuel cell power generation apparatus abnormality detection method according to the present invention. FIG. In this figure, components having the same functions as those used in the conventional basic configuration shown in FIG. 2 are denoted by the same reference numerals, and redundant description is omitted.
[0013]
A feature of the embodiment shown in the figure is that a blow-down circuit for discharging the internal stored water provided in the steam separator 5 is provided with a thermometer 21 instead of the conventional flow meter 10, In the recycle gas circuit, the heat dissipating fins 22 are provided on the upstream side of the thermometer 21 as a circuit heat dissipating means, and a part of the fuel gas obtained by the fuel reformer is recirculated to the desulfurizer. Instead of the conventional flow meter 9, a thermometer 11 is provided, and a heat radiating fin 12 is provided on the upstream side of the thermometer 11 as a heat radiating means of the circuit.
[0014]
Therefore, in this configuration, if the flow rate of the blowdown water flowing through the blowdown circuit is reduced for some reason, the indicated value of the thermometer 21 is significantly reduced due to the balance with heat dissipation. An abnormality in the flow rate of the blow-down water can be detected depending on whether or not it departs from the predetermined range. Similarly, in the recycle gas circuit, if the flow rate of the recycle gas is reduced, the indicated value of the thermometer 11 is significantly reduced due to the balance with heat dissipation, so that the indicated value of the thermometer 11 departs from a predetermined range. Whether or not the recycle gas flow rate is abnormal can be detected. The thermometer 21 and the thermometer 11 used in this configuration are much cheaper than the flowmeter with an oscillator employed in the conventional example, and a temperature abnormality, that is, a flow abnormality is detected by a simple control device. Therefore, if monitoring is performed using the detection means having the configuration of this configuration, an abnormality can be easily detected at a low cost and with little effort.
[0015]
In FIG. 1, a thermometer is incorporated in both the blowdown circuit and the recycle gas circuit to detect an abnormality, but a thermometer is incorporated only in one circuit to detect an abnormal flow rate in that circuit. It is good. In addition, the flow rate abnormality can be detected with high sensitivity if a heat radiating means such as the heat radiating fins 12 and 22 is incorporated. However, even if the heat radiating means is not particularly incorporated, the temperature decreases if the flow rate decreases, so that the flow rate abnormality can be detected. It will be clear soon.
[0016]
【The invention's effect】
As described above, in the present invention,
(1) Since the method as described in claim 1 is used, a decrease in the flow rate of the blow-down circuit can be easily detected at low cost.
(2) Since the method as described in claim 2 is used, a decrease in the flow rate of the recycle gas circuit can be detected at low cost and easily.
[0017]
(3) Furthermore, if it is as described in Claim 3, since the fall of a flow volume is detected more sensitively, it is more suitable as a method of detecting the abnormality of a flow volume cheaply and easily.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of the basic configuration of a fuel gas supply system, an air supply system, and a cooling water system of a fuel cell power generation apparatus showing an embodiment of an abnormality detection method for a fuel cell power generation apparatus according to the present invention. Schematic diagram showing the basic configuration of the fuel gas supply system, air supply system, and cooling water system of the battery power generation system.
DESCRIPTION OF SYMBOLS 1 Fuel cell main body 2 Fuel reformer 3 Ejector pump 4 Hydrodesulfurizer 5 Steam separator 6 Cooling water cooler 7 Generated water collector 8 Water treatment device 11 Thermometer 12 Radiation fin 21 Thermometer 22 Radiation fin

Claims (3)

A fuel cell body that is provided with a cooling plate through which cooling water flows, and high-temperature cooling water discharged from the cooling plate are introduced and separated into water vapor and water, and the raw fuel is converted into fuel gas. the water vapor separator supplied to the cooling plate, the cathode off-gas and the fuel reformer of the combustion exhaust gas of the fuel cell body to the water with and quality supplying the steam to the fuel reformer for supplying to the fuel cell body In a method for detecting an abnormality in a fuel cell power generation apparatus, comprising: a generated water recovery device that recovers generated water contained therein, wherein the generated water recovered by the generated water recovery device is purified by a water treatment device and introduced into a steam separator ,
Detecting an abnormality in the flow rate of blowdown water when an indication value of a thermometer provided in a blowdown circuit that discharges the stored water inside the water vapor separator to the generated water recovery device deviates from a predetermined range. An abnormality detection method for a fuel cell power generator characterized by the above. A desulfurizer that introduces raw fuel and desulfurizes the sulfur contained in it by adding hydrogen, and high-temperature cooling water discharged from a cooling plate interposed in the fuel cell body is introduced to separate water vapor and water. An ejector pump that introduces and mixes water vapor from a water vapor separator that supplies water to the cooling plate and the desulfurized raw fuel, and a fuel gas having a high hydrogen concentration by introducing the raw fuel mixed with water vapor Equipped with a fuel reformer that reforms the fuel, and a recycle gas circuit that mixes part of the fuel gas obtained in the fuel reformer with the raw fuel introduced into the desulfurizer and uses the hydrogen contained in the desulfurization In the fuel cell power generator abnormality detection method,
An abnormality detection method for a fuel cell power generation apparatus, wherein an abnormality in a flow rate of a recycle gas is detected when an indication value of a thermometer provided in the recycle gas circuit departs from a predetermined range. A heat dissipating means for promoting heat dissipation of the circuit is provided upstream of the thermometer of the circuit provided with the thermometer, and an abnormal flow rate is detected when the indicated value of the thermometer deviates from a predetermined range. The abnormality detection method for a fuel cell power generator according to claim 1 or 2, characterized in that:

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