JP2011210586A - Fuel battery power generating apparatus, control program, and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery power generating apparatus capable of surely detecting failure of water supply to a water vaporizer and safely controlling power generation of a fuel battery power generating apparatus.SOLUTION: The fuel battery power generating apparatus at least includes: a fuel battery module containing a fuel reformer and a fuel cell stack; a fuel gas supplier for supplying a fuel gas to the fuel cell stack; an oxidizer gas supplier for supplying an oxidizer gas to the fuel cell stack; a water vapor supplier for introducing water vapor to a supply passage of the fuel gas; and a controller. Here, the vapor supplier is arranged on a boundary section of the fuel battery module, and includes the water vaporizer for generating water vapor by making use of heat of an exhaust gas from the fuel battery module, and has a temperature measuring portion in the vicinity of a discharge port of water vapor of the water vaporizer and/or a discharge port of the exhaust gas. The controller controls power generation of the fuel battery power generating apparatus on the basis of temperature of the water vapor and/or exhaust gas measured at the temperature measuring portion during power generation of the fuel battery power generating apparatus.

Description

  The present invention relates to a fuel cell power generation apparatus and a control program and control method for controlling the fuel cell power generation apparatus, and more particularly to a fuel cell power generation apparatus that generates power using fuel gas reformed by a steam reforming reaction, and The present invention relates to a control program and a control method.

  In recent years, fuel cell power generation devices that generate electricity by gas electrochemical reaction have high power generation efficiency, and the discharged gas is clean and has very little influence on the environment. This fuel cell power generation device can be classified according to the reaction temperature and the type of electrolyte. The low temperature type having a reaction temperature of about 300 ° C. or lower includes a solid polymer type (PEFC), an alkaline type (AFC), and a phosphoric acid type. (PAFC) and the like, and the high temperature type includes a molten carbonate type (MCFC) and a solid oxide type (SOFC).

  Among them, the solid oxide type has a high operating temperature, so there is no need to use an expensive noble metal catalyst such as Pt, it is easy to use exhaust heat, and the battery components are all solid. Therefore, the structure is simple and high power generation efficiency can be obtained, and development has been actively conducted in recent years. Fuel cell power generators are classified into three types according to the shape of the power generation cell: a cylindrical type, a monolith type, and a flat plate stack type, and a flat plate stack type that facilitates the formation of power generation cells is widely adopted.

  The flat plate solid oxide fuel cell device has a fuel cell stack in which power generation cells and separators are alternately stacked. The power generation cell has a stacked structure in which a solid electrolyte layer made of an oxide ion conductor is sandwiched between an air electrode (cathode) layer and a fuel electrode (anode) layer, and oxygen ( Air) and fuel gas is supplied to the fuel electrode side.

  The air electrode layer and the fuel electrode layer are formed of a porous material so that oxygen and fuel gas can reach the interface with the solid electrolyte layer. Further, the separator or interconnector has a passage for electrically connecting the power generation cells and introducing fuel gas or oxidant gas from the outer peripheral surface of the separator and discharging the gas toward the fuel electrode layer. An air electrode current collector is disposed between the separator and the air electrode layer, and a fuel electrode current collector is disposed between the separator and the fuel electrode layer.

In the solid oxide fuel cell having the above configuration, the oxidant gas (oxygen) supplied to the air electrode side of the power generation cell via the separator reaches the vicinity of the interface with the solid electrolyte layer through the pores in the air electrode layer. Then, electrons are received from the air electrode and become oxide ions (O ²⁻ ). This oxide ion diffuses and moves in the solid electrolyte layer toward the fuel electrode, reacts with the fuel gas near the interface with the fuel electrode to become a reaction product (such as H ₂ O), and emits electrons to the fuel electrode. To do. And an electric current generate | occur | produces by taking out this electron from a fuel electrode electrical power collector. The electrode reaction (power generation reaction) is as follows when hydrogen is used as the fuel gas.

Air electrode: 1 / 2O ₂ + 2e ⁻ → O ²⁻
Fuel electrode: H ₂ + O ²⁻ → H ₂ O + 2e ⁻
Overall: H ₂ + 1 / 2O ₂ → H ₂ O

  Here, when hydrogen is used as the fuel gas, nitrogen is mixed in order to control the concentration of hydrogen, but the amount of nitrogen used increases as the apparatus becomes larger. Therefore, a fuel cell power generation apparatus has been proposed that uses a hydrocarbon gas such as city gas or natural gas instead of hydrogen as the fuel gas (see, for example, Patent Document 1 below).

  For example, as shown in FIG. 8, the fuel cell power generator includes a fuel cell stack 3 that generates DC output power according to the flow rate of fuel gas and the flow rate of oxidant gas, and oxidant gas in the fuel cell stack 3. An air supply system that introduces fuel, a fuel gas supply system that introduces fuel gas into the fuel cell stack 3, and a fuel reformer 4 that reforms a hydrocarbon-based gas sent from the fuel gas supply system into a hydrogen-rich fuel gas And a water vapor supply system that introduces water vapor into the fuel gas supply system, a control unit 5 that performs various controls, and the like, and the fuel cell stack 3 and the fuel reformer 4 constitute the fuel cell module 2. Further, the water vapor supply system includes a water vaporizer 10 that is installed at a boundary portion of the fuel cell module 2 and vaporizes water using heat of exhaust gas discharged from the fuel cell module 2 to generate water vapor. .

JP 2002-260697 A

In the reaction between hydrocarbon gas and steam (so-called steam reforming reaction), water is vaporized and mixed with hydrocarbon gas (natural gas mainly composed of methane, propane or liquid kerosene, etc.) and nickel ( When introduced into a reforming catalyst containing Ni) or ruthenium (Ru) and heated at 500 to 700 ° C., the chemical reaction proceeds, and hydrogen (H ₂ ), carbon dioxide (CO ₂ ) and, in some cases, carbon monoxide. (CO) is made. Then, the reformed hydrogen or carbon monoxide generates electric power by the battery reaction.

  Therefore, in a fuel cell power generator using hydrocarbon gas, it is important to stably generate water vapor by the water vaporizer 10. Here, in general, water is supplied to the water vaporizer 10 from the pure water tank 9 by the water transfer pump 8. For example, a valve for supplying water to the pure water tank 9 is closed and the pure water tank 9 is emptied. In some cases, water may not be supplied to the water vaporizer 10 due to some trouble, such as when the water transfer pump 8 fails.

  Such a drainage means that only the hydrocarbon gas is supplied to the fuel cell module operating at a high temperature, and only the hydrocarbon gas is supplied to the fuel reformer 4 operating at 500 to 700 ° C. Then, a coking phenomenon occurs, the hydrocarbon-based gas is decomposed into carbon and hydrogen, and carbon accumulates in the fuel reformer 4 and is blocked. In such a state, hydrogen is not supplied to the fuel cell stack 3, which leads to a decrease in voltage of the power generation cell and a decrease in electrical output. Further, due to the blockage in the fuel reformer 4, the supply gas pressure rises and there is a risk of gas explosion.

  In order to avoid the above problem, it is necessary to reliably prevent the water supply from being stopped during power generation by the fuel cell power generation apparatus. As a method for this, a method of monitoring the operation of the water transfer pump 8 can be considered. However, the water transfer pump 8 may idle when there are bubbles in the supplied water. In this state, since the power system is rotating, the control system determines that there is no problem. Therefore, it is impossible to reliably detect a decrease or stop in the water supply.

  As another method, a method of monitoring the flow rate of water by providing a water flow meter after the water transfer pump 8 is also conceivable. However, since the existing water flowmeter has a large error and easily breaks down, it is still impossible to reliably detect a decrease or stoppage of the water supply.

  The present invention has been made in view of the above problems, and its main object is to solve the problem of water supply in a fuel cell power generation apparatus that generates power using fuel gas reformed by a steam reforming reaction. An object of the present invention is to provide a fuel cell power generation device capable of reliably detecting and safely stopping power generation of the fuel cell power generation device or reducing the power generation output, a control program for the fuel cell power generation device, and a control method.

  To achieve the above object, the present invention includes a fuel reformer that reforms a hydrocarbon-based fuel gas, and a fuel cell stack that generates electric power by a reaction between the reformed fuel gas and an oxidant gas. A fuel cell module; fuel gas supply means for supplying the fuel gas to the fuel cell stack via the fuel reformer; oxidant gas supply means for supplying the oxidant gas to the fuel cell stack; In the fuel cell power generation device comprising at least a water vapor supply means for introducing water vapor into the fuel gas supply path to the fuel reformer, and a control unit, the water vapor supply means is disposed at a boundary portion of the fuel cell module A water vaporizer that vaporizes water supplied using heat of exhaust gas discharged from the fuel cell module and generates water vapor, and water in the water vaporizer A temperature measurement unit is provided in the vicinity of the gas discharge port and / or in the vicinity of the exhaust gas discharge port, and the control unit acquires the temperature of the water vapor and / or the exhaust gas measured by the temperature measurement unit during power generation of the fuel cell power generation device. The power generation of the fuel cell power generator is controlled based on the acquired temperature.

  The present invention also includes a fuel cell module including a fuel reformer that reforms a hydrocarbon-based fuel gas and a fuel cell stack that generates electric power by a reaction between the reformed fuel gas and an oxidant gas; A fuel gas supply means for supplying the fuel gas to the fuel cell stack via the fuel reformer, an oxidant gas supply means for supplying the oxidant gas to the fuel cell stack, and a boundary between the fuel cell modules Supply of the fuel gas to the fuel reformer, including a water vaporizer that is disposed in a portion and vaporizes water supplied using heat of exhaust gas discharged from the fuel cell module and generates water vapor A program for controlling a fuel cell power generation device comprising at least a water vapor supply means for introducing water vapor into the path; Sometimes, the temperature of the water vapor and / or exhaust gas measured by a temperature measuring unit provided in the vicinity of the water vapor outlet and / or in the vicinity of the exhaust gas outlet of the water vaporizer is acquired, and the fuel cell is based on the acquired temperature. It functions as a control unit that controls power generation of the power generation device.

  The present invention also includes a fuel cell module including a fuel reformer that reforms a hydrocarbon-based fuel gas and a fuel cell stack that generates electric power by a reaction between the reformed fuel gas and an oxidant gas; A fuel gas supply means for supplying the fuel gas to the fuel cell stack via the fuel reformer, an oxidant gas supply means for supplying the oxidant gas to the fuel cell stack, and a boundary between the fuel cell modules Supply of the fuel gas to the fuel reformer, including a water vaporizer that is disposed in a portion and vaporizes water supplied using heat of exhaust gas discharged from the fuel cell module and generates water vapor A method for controlling a fuel cell power generation device, comprising: a water vapor supply means for introducing water vapor into a path; and a first step of starting the fuel cell power generation device to generate power A second step of acquiring the temperature of water vapor and / or exhaust gas measured by a temperature measuring unit provided in the vicinity of the water vapor outlet and / or in the vicinity of the exhaust gas outlet of the water vaporizer during power generation by the fuel cell power generator. And a third step of controlling the power generation of the fuel cell power generator based on the acquired temperature.

  According to the fuel cell power generation device, the control program, and the control method of the present invention, it is possible to reliably detect a failure in water supply and safely stop the power generation of the fuel cell power generation device or reduce the power generation output.

  The reason is that a water vapor temperature measuring unit is provided in the vicinity of the water vapor outlet of the water vaporizer arranged at the boundary portion of the fuel cell module, and the state of water supply to the water vaporizer is judged based on the temperature of the water vapor. is there. In addition, an exhaust gas temperature measurement unit is provided in the vicinity of the exhaust gas discharge port of the water vaporizer, and the state of water supply to the water vaporizer is determined based on the temperature of the exhaust gas.

It is a figure which shows typically the structure of the fuel cell electric power generating apparatus which concerns on one Example of this invention. It is a figure which shows the specific structure of the fuel cell stack which concerns on one Example of this invention. It is a figure which shows typically the structure of the electric power generation cell which concerns on one Example of this invention. It is a figure which shows the specific structure of the water vaporizer which concerns on one Example of this invention. It is a flowchart figure which shows the control procedure using the fuel cell electric power generating apparatus which concerns on one Example of this invention. It is a figure which shows the correlation with the water vapor | steam temperature and the pure water flow rate in the fuel cell electric power generating apparatus which concerns on one Example of this invention. It is a figure which shows the correlation with the exhaust gas temperature in the fuel cell power generator which concerns on one Example of this invention, and a pure water flow rate. It is a figure which shows typically the structure of the conventional fuel cell power generator.

  As shown in the background art, in a fuel cell power generation apparatus using hydrocarbon gas, it is important to stably generate water vapor with a water vaporizer, and it is possible to reduce or stop the water supply to the water vaporizer. It needs to be detected reliably. Therefore, conventionally, a decrease or stoppage of the water supply to the water vaporizer was detected based on the operation state of the water transfer pump or a change in the flow rate of water supplied to the water vaporizer. In the latter case, there is a problem that the water flow meter cannot detect a decrease or stop of the water supply reliably because the error is large and there are many failures. .

  Here, the fuel cell module operates with a good balance between electricity and heat in a power generation state. In this state, the flow rate of the hydrocarbon gas to be supplied, the water flow rate, and the air flow rate are substantially constant, and considering the heat balance of the fuel cell module, the exhaust gas discharged from the fuel cell module to the water vaporizer Is equal to the heat amount used when the water vaporizer heated by the exhaust gas vaporizes water and the heat amount of the exhaust gas discharged from the water vaporizer to the outside.

  For example, when the water vaporizer is located at a distance from the fuel cell module, if the temperature of the fuel cell stack is 600 to 850 ° C., the temperature in the fuel cell module is 500 to 600 ° C. The exhaust gas from the fuel cell module at 500 to 600 ° C. is heat-exchanged in the water vaporizer, and the heat of the exhaust gas is taken as the heat of vaporization of water, resulting in an exhaust gas temperature of about 50 to 300 ° C.

  Thus, when water is supplied at a constant flow rate, the temperature of the water vapor and the temperature of the exhaust gas from the fuel cell module are almost constant, but if the water supply is reduced or stopped for some reason, the water vaporization Since the water level in the vessel decreases and the path through which the generated water vapor is heated and discharged becomes longer, the temperature of the water vapor rises. Further, when the water level in the water vaporizer is lowered, the path through which the exhaust gas is cooled by the heat of vaporization of water is shortened, so that the temperature of the exhaust gas also increases.

  Therefore, in one embodiment of the present invention, the temperature of at least one of the vicinity of the water vapor outlet and the vicinity of the exhaust gas outlet of the water vaporizer is monitored and compared with a predetermined threshold value, and the water vapor temperature and / or the exhaust gas temperature is the threshold value. If it is above (or below the threshold), it is determined that a water supply failure has occurred. As a result, it is possible to detect a water supply failure more reliably and safely, compared to the method of monitoring the operation of the water transfer pump and the water flow rate in the path between the water transfer pump and the water vaporizer. The battery power generation device can be stopped or the power generation output can be reduced.

  In addition, a considerable amount of water is stored in the water vaporizer of the fuel cell power generation apparatus during power generation in order to stably vaporize the water. Even if the water supply is suddenly stopped, the stored water remains. Since there is a predetermined time before it runs out, it is possible to safely stop the power generation of the fuel cell power generation device or reduce the power generation output.

  In order to describe the above-described embodiment of the present invention in more detail, a control program and a control method for a fuel cell power generator and a fuel cell power generator according to an embodiment of the present invention will be described with reference to FIGS. explain. FIG. 1 is a diagram schematically illustrating the configuration of the fuel cell power generation device of the present embodiment, FIG. 2 is a diagram illustrating a specific configuration example of the fuel cell stack in the fuel cell module, and FIG. 3 is a power generation cell. FIG. FIG. 4 is a diagram showing a specific configuration example of the water vaporizer, and FIG. 5 is a flowchart showing a control procedure using the fuel cell power generator of this embodiment. FIG. 6 is a diagram showing the correlation between the flow rate of pure water supplied to the water vaporizer and the temperature of water vapor discharged from the water vaporizer, and FIG. It is a figure which shows the correlation with the temperature of the waste gas discharged | emitted from a gasifier.

  As shown in FIG. 1, the fuel cell power generator 1 of the present embodiment includes a flow rate of a fuel gas (natural gas mainly composed of methane, hydrocarbon gas such as propane or liquid kerosene) and an oxidant gas (oxygen gas). The fuel cell stack 3 that generates DC output power according to the flow rate of the air and the air), the air blower 6 that introduces the oxidant gas (air in this embodiment) into the fuel cell stack 3, and the air supply piping. An air supply system such as a fuel gas blower 7 for introducing fuel gas into the fuel cell stack 3 and a fuel gas supply system such as a fuel gas supply pipe, and the like, are disposed in the fuel cell module 2 and sent from the fuel gas supply system. A fuel reformer 4 for reforming the hydrocarbon-based gas into a hydrogen-rich fuel gas, a water supply pump 8 or a water vaporizer 10 for introducing water vapor into the fuel gas supply system, a water vapor supply system such as a water vapor supply pipe, moisture A water vapor temperature measuring unit 20 for measuring the temperature of water vapor discharged from the vessel 10, an exhaust gas temperature measuring unit 21 for measuring the temperature of exhaust gas discharged from the water vaporizer 10, and flow control of water, fuel gas, and air, The control unit 5 performs power generation control based on the water vapor temperature or the exhaust gas temperature, and an inverter (not shown) that converts the direct current output from the fuel cell stack 3 into alternating current output and supplies alternating current power to an external load. ing.

  The water vaporizer 10 is disposed at a boundary portion of the fuel cell module 2 so that water vapor can be generated by effectively using the exhaust heat of the fuel cell module 2. Further, the water vapor temperature measuring unit 20 and the exhaust gas temperature measuring unit 21 are constituted by a thermocouple or the like, and the output thereof is input to the control unit 5.

  In addition, the control unit 5 is normally provided in the control device of the fuel cell power generation device 1 and is configured to operate in cooperation with an arithmetic processing unit, a display unit, an operation unit, and the like of the control device. The control unit 5 may be configured as hardware in the control device, or may be configured as a control program that causes a computer (a general term for hardware resources capable of executing software) to function as the control unit 5. The control program may be executed by a control device.

  Next, specific configurations of the fuel cell stack 3 and the power generation cells will be described with reference to FIGS. 2 and 3.

  As shown in FIG. 2, the fuel cell stack 3 includes a power generation cell 14 in which a fuel electrode layer 13 and an air electrode layer 11 are disposed on both surfaces of a solid electrolyte layer 12, and a fuel electrode assembly disposed outside the fuel electrode layer 13. A single cell (unit) comprising an electric body 19, an air electrode current collector 18 disposed outside the air electrode layer 11, and a separator 17 (also referred to as an interconnector) disposed outside each current collector is vertically arranged. A large number of layers are stacked in the direction.

The solid electrolyte layer 12 is composed of lanthanum gallate (La _0.8 Sr _0.2 Ga _0.8 Mg _0.15 Co _0.05 O _2.85 ), stabilized zirconia (YSZ) to which yttria is added, and the like. The fuel electrode layer 13 is made of a metal such as Ni or Co or a cermet of Ni—YSZ, Co—YSZ, Ni and samarium-doped ceria (Ce _0.8 Sm _0.2 O ₂ ), and the air electrode layer 11 , Samarium cobaltite (Sm _0.5 Sr _0.5 CoO ₃ ), lanthanum manganite (LaMnO ₃ ), lanthanum iron cobaltite (LaSrCoFeO ₃ ) and the like. The fuel electrode current collector 19 is composed of a sponge-like porous sintered metal plate such as a Ni-based alloy, and the air electrode current collector 18 is composed of a sponge-like porous sintered metal plate such as an Ag-based alloy. Has been.

  The separator 17 is made of stainless steel or the like, an Ag plating layer is formed on the surface on the air electrode current collector 18 side, and an Ni plating layer is formed on the surface on the fuel electrode current collector 19 side. 14 are electrically connected. The separator 17 has a function of supplying gas to the power generation cell 14, and introduces fuel gas from the outer peripheral surface of the separator 17 and discharges it from the substantially central portion of the surface facing the fuel electrode current collector 19. A fuel gas flow path and an oxidant gas flow path for introducing an oxidant gas (air) from the outer peripheral surface of the separator 17 and discharging it from the substantially central portion of the surface facing the air electrode current collector 18 are provided.

  As shown in the schematic diagram of FIG. 3, during operation, the fuel gas and the oxidant gas (air) supplied from the substantially central portion of the separator 17 to the power generation cell 14 through the fuel gas passage and the oxidant gas passage are supplied. While diffusing in the outer peripheral direction of the power generation cell 14, it spreads over the entire surface of the fuel electrode layer 13 and the air electrode layer 11 with a good distribution to generate a power generation reaction, and surplus gas (high temperature exhaust gas) not consumed in the power generation reaction is generated. The exhaust gas discharged from the outer peripheral portion of the power generation cell 14 into the housing is freely discharged, and the exhaust gas discharged into the inner space of the housing passes through the water vaporizer 10 and is discharged out of the fuel cell module 2. Yes.

  Further, as shown in FIG. 2, a pair of end plates 15 and 16 made of stainless steel or the like are disposed on both sides of the fuel cell stack 3, and the power of the fuel cell stack 3 is supplied to the pair of upper and lower end plates. 15 and 16 can be taken out and can be measured by output measuring means provided outside. Further, as shown in FIG. 3, the cell voltage of one or a plurality of power generation cells 14 (in FIG. 3, individual power generation cells 14) can be taken out to the outside through wiring connected to the separator 17, and It can be measured by the provided output measuring means.

  2 and 3 show a configuration in which the fuel electrode current collector 19 and the air electrode current collector 18 are arranged on both sides of the power generation cell 14, the fuel electrode current collector 19 and the air electrode current collector are shown. The present invention can be applied to a configuration in which the body 18 is not arranged. In addition, in FIG. 2, the fuel cell stack 3 having a sealless structure in which the gas leakage prevention seal is not provided on the outer peripheral portion of the power generation cell 14 is shown. The present invention can be applied.

  Next, a specific configuration of the water vaporizer 10 will be described with reference to FIG. Fig.4 (a) is a front view of the water vaporizer 10, FIG.4 (b) is the side view.

  In general, the water vaporizer 10 is composed of a heat exchanger accommodated in a space surrounded by a heat insulating material, and is introduced from a water supply port 10c at the bottom of the heat exchanger as shown in FIG. In the process of flowing water upward, heat exchange with the high-temperature exhaust gas from the fuel cell stack 3 introduced from the upper exhaust gas inlet 10a becomes high-temperature steam, and the fuel reformer passes through the steam outlet 10d at the upper end. 4 is guided. Further, the exhaust gas introduced from the upper exhaust gas inlet 10a finishes heat exchange with the supply water in the process of flowing downward, becomes low-temperature exhaust gas, and is discharged to the outside from the lower exhaust gas outlet 10b.

  Although the heat exchanger is not shown in the figure, for example, an exhaust gas channel with fins through which exhaust gas from the fuel cell stack 3 flows and a water channel with fins through which supply water from the outside flows cross or face each other in plate units. The gap between the fins in the water flow path is filled with alumina beads having a diameter of 1 to 2 mm and excellent thermal conductivity.

  In the water vaporizer 10 having the above-described structure, water is accumulated up to a certain level in the heat exchanger, water vapor is generated in the portion where the water is accumulated, and the water vapor is further heated in the process of moving upward, It is discharged from the outlet 10d. Therefore, when the water level is lowered, the path until the water vapor is heated and discharged becomes longer, so that the water vapor having a higher temperature is discharged from the water vapor discharge port 10d.

  Further, the exhaust gas from the fuel cell stack 3 is discharged from the exhaust gas discharge port 10b with the temperature lowered by the heat of vaporization of water in the portion where water is accumulated. Therefore, when the water level is lowered, the path through which the temperature is lowered due to the heat of vaporization of water is shortened, so that the exhaust gas having a higher temperature is discharged from the exhaust gas discharge port 10b.

  Thus, the water level in the water vaporizer 10 (heat exchanger) (that is, the amount of water supplied), the temperature of the water vapor discharged from the water vapor outlet 10d, and the temperature of the exhaust gas discharged from the exhaust gas outlet 10b. Therefore, if the temperature of the water vapor is measured by the water vapor temperature measuring unit 20 provided near the water vapor outlet 10d or the temperature of the exhaust gas is measured by the exhaust gas temperature measuring unit 21 provided near the exhaust gas outlet 10b. Thus, it is possible to reliably detect that the water supply has decreased or stopped.

  In the conventional method of monitoring the operating state of the water transfer pump 8 and the water flow rate in the downstream path of the water transfer pump 8, for example, water leakage occurs in the water vaporizer 10 (heat exchanger) and the water level is lowered. In this case, the abnormality cannot be detected when the temperature of the exhaust gas rises due to an abnormal reaction of the fuel cell stack 3, but the method of this embodiment is directly related to the water level in the water vaporizer 10 (heat exchanger). Since the water vapor temperature and exhaust gas temperature to be used are utilized, even in such a case, an abnormality can be detected. Therefore, it can be said that the method of this embodiment is a better control method than the conventional method.

  Hereinafter, a specific control procedure using the fuel cell power generator configured as described above will be described with reference to the flowchart of FIG.

  First, in step S101, when the activation of the fuel cell power generation device 1 is instructed by a button operation of the control device or the like in the cold standby state (normal temperature state), the control unit 5 starts the fuel cell module 2 with a heater for activation, The fuel cell stack 3 is heated to a temperature at which power can be generated by heating with a burner.

  Next, in step S102, the control unit 5 controls the air supply system to supply a predetermined flow rate of air to the fuel cell stack 3, and subsequently, in step S103, controls the fuel gas supply system and the water vapor supply system. Thus, fuel gas and water vapor at a predetermined flow rate are supplied to the fuel cell stack 3.

  Next, in step S104, the control unit 5 monitors the temperature of the fuel cell stack 3 using temperature measuring means, and in step S105, compares the temperature of the fuel cell stack 3 with a predetermined temperature, When the temperature reaches the temperature, it is determined that a hot standby state has been reached. In step S106, power generation is started and rated operation is performed.

  During this rated operation, in step S107, the control unit 5 acquires the temperature of the water vapor from the water vapor temperature measurement unit 20 provided in the vicinity of the water vapor discharge port 10d of the water vaporizer 10 (or the exhaust gas discharge port of the water vaporizer 10). The temperature of the exhaust gas is acquired from the exhaust gas temperature measuring unit 21 provided in the vicinity of 10b) and compared with a predetermined threshold value.

  When the water vapor temperature or the exhaust gas temperature is equal to or higher than the threshold, the control unit 5 determines that the water supply has decreased or stopped, and in step S108, the warning lamp is turned on / flashed as necessary. After performing a warning process to notify that the water supply to the water vaporizer 10 has decreased or stopped by sounding a warning sound or displaying a warning message, the power generation is stopped or the power generation output is decreased in step S110. Process such as.

  On the other hand, if the water vapor temperature or the exhaust gas temperature is less than the threshold value in step S107, in step S109, the control unit 5 determines whether power generation stop is instructed, and continues power generation until instructed.

  FIG. 6 is a diagram showing the correlation between the temperature of water vapor near the water vapor outlet 10d measured by the water vapor temperature measuring unit 20 and the flow rate of pure water introduced into the water inlet 10c. It can be seen that the temperature of the water vapor gradually rises as the supply of pure water decreases, although the water vapor is at a constant temperature (about 543 ° C.) when pure water is flowing at a minute). Therefore, if the water vapor temperature threshold is set to a temperature (for example, 545 ° C.) that is slightly higher than the value during rated operation (here, 543 ° C.), it is possible to reliably detect a decrease or stop in water supply. it can.

  FIG. 7 is a diagram showing the correlation between the temperature of the exhaust gas near the exhaust gas outlet 10b measured by the exhaust gas temperature measuring unit 21 and the flow rate of pure water introduced into the water inlet 10c. When pure water is flowing at 13 mL / min), the exhaust gas has a constant temperature (about 225 ° C.), but it can be seen that the temperature of the exhaust gas gradually increases as the supply of pure water decreases. Therefore, if the temperature threshold of the exhaust gas is set to a temperature (for example, 250 ° C.) slightly higher than the value during rated operation (here, 225 ° C.), it is possible to reliably detect a decrease or stop in water supply. it can.

  6 and 7 show the correlation between the water vapor temperature or exhaust gas temperature during the rated operation and the pure water flow rate. Even when the power generation is performed while changing the output, the normal operation is performed. The correlation data between the output and the steam temperature or exhaust gas temperature is stored, the measured steam temperature or exhaust gas temperature is compared with the steam temperature or exhaust gas temperature corresponding to the current output, and the measured value is within the appropriate temperature range. When deviating, it can be determined that the water supply has been reduced or stopped.

  Thus, in the fuel cell power generator 1 of the present embodiment, the control unit 5 reduces or stops the water supply to the water vaporizer 10 when the water vapor temperature or the exhaust gas temperature in the vicinity of the water vaporizer 10 exceeds the threshold value. Therefore, it is possible to safely stop the power generation of the fuel cell power generation device or reduce the power generation output.

  In addition, in the said Example, although the two temperature measurement means of the water vapor | steam temperature measurement part 20 and the exhaust gas temperature measurement part 21 were provided, it should just contain at least 1 temperature measurement means.

  Further, in the above embodiment, when the water vapor temperature or the exhaust gas temperature is increased, it is determined that the water level in the water vaporizer has decreased, and the power generation is stopped or the power generation output is reduced. Since the correlation between the water level in the water vaporizer and the water vapor temperature or exhaust gas temperature is used, the water supply increases (the water level in the water vaporizer rises) when the water vapor temperature or the exhaust gas temperature falls. It is also possible to adopt a configuration in which a judgment is made and a warning is given, or power generation is stopped or control for reducing the power generation output is performed.

  Moreover, in the said Example, although the sealless type fuel cell power generator 1 was described, this invention is not limited to the said Example, The same effect is acquired also in a seal type fuel cell power generator 1. be able to.

  The present invention is particularly effective in a solid oxide fuel cell power generator, but other types such as a solid polymer fuel cell power generator, a phosphoric acid fuel cell power generator, and a molten carbonate fuel cell power generator. It can also be used for a fuel cell power generator.

DESCRIPTION OF SYMBOLS 1 Fuel cell power generation device 2 Fuel cell module 3 Fuel cell stack 4 Fuel reformer 5 Control part 6 Air blower 7 Fuel gas blower 8 Water transfer pump 9 Pure water tank 10 Water vaporizer 10a Exhaust gas inlet 10b Exhaust gas outlet 10c Water supply Port 10d Water vapor outlet 11 Air electrode layer 12 Solid electrolyte layer 13 Fuel electrode layer 14 Power generation cell 15, 16 End plate 17 Separator 18 Air electrode current collector 19 Fuel electrode current collector 20 Water vapor temperature measuring unit 21 Exhaust gas temperature measuring unit

Claims (9)

A fuel reformer for reforming a hydrocarbon-based fuel gas; a fuel cell module including a fuel cell stack for generating electric power by a reaction between the reformed fuel gas and an oxidant gas; and the fuel reformer. Fuel gas supply means for supplying the fuel gas to the fuel cell stack, oxidant gas supply means for supplying the oxidant gas to the fuel cell stack, and supply of the fuel gas to the fuel reformer In a fuel cell power generator comprising at least a water vapor supply means for introducing water vapor into the path, and a controller,
The water vapor supply means includes a water vaporizer that is disposed at a boundary portion of the fuel cell module, vaporizes water supplied using heat of exhaust gas discharged from the fuel cell module, and generates water vapor,
A temperature measuring unit is provided in the vicinity of the water vapor outlet and / or the exhaust gas outlet of the water vaporizer,
The controller is
A fuel characterized in that, during power generation by the fuel cell power generation device, the temperature of water vapor and / or exhaust gas measured by the temperature measurement unit is acquired, and power generation of the fuel cell power generation device is controlled based on the acquired temperature. Battery power generator. The controller is
When the temperature of the water vapor and / or exhaust gas measured by the temperature measuring unit is equal to or higher than a predetermined threshold, or when the temperature is equal to or lower than a predetermined threshold, power generation of the fuel cell power generation device is stopped or power generation output The fuel cell power generator according to claim 1, wherein The controller is
3. The fuel cell according to claim 2, wherein a warning is given to inform the water vaporizer that water is not properly supplied before stopping the power generation of the fuel cell power generation device or reducing the power generation output. Power generation device. A fuel reformer for reforming a hydrocarbon-based fuel gas; a fuel cell module including a fuel cell stack for generating electric power by a reaction between the reformed fuel gas and an oxidant gas; and the fuel reformer. A fuel gas supply means for supplying the fuel gas to the fuel cell stack, an oxidant gas supply means for supplying the oxidant gas to the fuel cell stack, and a boundary portion of the fuel cell module, Water is introduced into the fuel gas supply path to the fuel reformer, including a water vaporizer that vaporizes water supplied using the heat of exhaust gas discharged from the fuel cell module and generates water vapor. A program for controlling a fuel cell power generator comprising at least a water vapor supply means,
Computer
During the power generation of the fuel cell power generation device, the temperature of the water vapor and / or the exhaust gas measured by the temperature measuring unit provided in the vicinity of the water vapor outlet and / or in the vicinity of the exhaust gas outlet of the water vaporizer is acquired, and the acquired temperature And a control program for controlling the power generation of the fuel cell power generation apparatus based on the control program. The controller is
When the temperature of the water vapor and / or exhaust gas measured by the temperature measuring unit is equal to or higher than a predetermined threshold, or when the temperature is equal to or lower than a predetermined threshold, power generation of the fuel cell power generation device is stopped or power generation output The control program according to claim 4, wherein the control program is reduced. The controller is
6. The control program according to claim 5, wherein a warning is given to inform the water vaporizer that water is not properly supplied before stopping the power generation of the fuel cell power generation device or reducing the power generation output. . A fuel reformer for reforming a hydrocarbon-based fuel gas; a fuel cell module including a fuel cell stack for generating electric power by a reaction between the reformed fuel gas and an oxidant gas; and the fuel reformer. A fuel gas supply means for supplying the fuel gas to the fuel cell stack, an oxidant gas supply means for supplying the oxidant gas to the fuel cell stack, and a boundary portion of the fuel cell module, Water is introduced into the fuel gas supply path to the fuel reformer, including a water vaporizer that vaporizes water supplied using the heat of exhaust gas discharged from the fuel cell module and generates water vapor. A method of controlling a fuel cell power generator comprising at least a water vapor supply means,
A first step of activating the fuel cell power generator to generate power;
A second step of acquiring the temperature of water vapor and / or exhaust gas measured by a temperature measuring unit provided in the vicinity of the water vapor outlet and / or in the vicinity of the exhaust gas outlet of the water vaporizer during power generation by the fuel cell power generator. When,
And a third step of controlling power generation of the fuel cell power generation device based on the acquired temperature. In the third step,
When the temperature of the water vapor and / or exhaust gas measured by the temperature measuring unit is equal to or higher than a predetermined threshold, or when the temperature is equal to or lower than a predetermined threshold, power generation of the fuel cell power generation device is stopped or power generation output The method of controlling a fuel cell power generator according to claim 7, wherein: In the third step,
9. The fuel cell according to claim 8, wherein a warning is given to notify that the water vaporizer is not properly supplied with water before stopping the power generation of the fuel cell power generation device or reducing the power generation output. A method for controlling a power generator.

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