JP2008010258A - Starting system and starting method in solid oxide fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable quick starting while suppressing thermal stress generated in a cell in raising the temperature of the cell up to the operating temperature at starting a solid oxide fuel cell. <P>SOLUTION: This is provided with a fuel cell which is an assembly of the solid oxide fuel cell, a gas generating device for anode heating and the gas generating device for cathode heating to generate gas for heating supplied to an anode and a cathode, and a control device to control an operating state of both devices, and also provided with an average temperature estimating means of the cell at the control device, a thermal stress estimating means for estimating the surface thermal stress of the anode and the cathode, and a thermal stress control means for adjusting at least one of the operating state of the gas generating device for the anode heating and the operating state of the gas generating device for the cathode heating according to both surface thermal stresses. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an activation system and an activation method for raising the temperature of a fuel cell to an operating temperature during operation of a power generation system having a solid oxide fuel cell.

  In recent years, fuel cell power generation systems have attracted attention as one of clean and highly efficient distributed power sources. Among them, the solid oxide fuel cell power generation system capable of operating at high temperatures has a wide range of applications from business use to industrial use, and is expected in many fields as a future power source or a combined electric and heat supply system. However, since the solid oxide fuel cell that forms the core of the power generation system operates at a high temperature of 600 ° C. to 1000 ° C., at the time of start-up, the temperature can be safely and promptly increased from room temperature to a temperature of about 600 ° C. where power can be generated. It is necessary to raise the temperature. In addition, even when frequent start and stop are repeated, it is desirable to have high durability.

  In the solid oxide fuel cell power generation system, oxygen in the air supplied to the cathode side of the fuel cell is ionized, passes through the electrolyte, reaches the anode, and reacts with hydrogen supplied to the anode side. It uses a mechanism that generates electromotive force. In this case, hydrogen may be supplied directly to the anode, but it is converted into hydrogen-rich reformed gas by passing the raw material mixed with city gas or kerosene steam in advance through the reformer and used as fuel. The method to do is common.

  In such a solid oxide fuel cell power generation system, a particular problem is the thermal stress generated in the cell as the cell temperature rises at startup. A large thermal stress leads to cell cracking.

  As a prior art related to a start-up method of a solid oxide fuel cell power generation system, a burner is arranged between cells, and at the time of start-up, the start-up time is shortened by using this burner to increase the cell heating rate. (For example, refer to Patent Document 1). However, in this fuel cell, since the activation burner is arranged between the cells, the distance between the cells must be increased. As a result, the cell storage chamber is enlarged and the heat capacity is increased correspondingly, so that the effect of shortening the startup time is small.

  In addition, there is a type in which a gas burner is provided in the lower part of the fuel cell stack and the combustion gas is guided to the cathode to preheat the cell (see, for example, Patent Document 2).

  Further, there is a fuel cell operating temperature that is adjusted to a preset temperature change rate by adjusting the anode gas flow rate and the cathode gas flow rate (see, for example, Patent Document 3).

JP 2003-282129 A JP 2004-335163 A JP 2003-223912 A

  When the fuel cell is started, the temperature of the cell can be raised by supplying a heating gas to one or both of the anode side and the cathode side. However, if the temperature of the gas introduced at this time is too high or the temperature rises too fast, the difference between the cell surface temperature and the cell internal temperature will increase, and excessive thermal stress will be generated on the cell surface accordingly. There is a fear. Therefore, there is a demand for a temperature raising method for suppressing the thermal stress generated on the cell surface at the time of startup to a value below an allowable value.

  However, the above-described conventional technology has not yet solved the problem of how to suppress the thermal stress generated in the cell to an allowable value or less and realize rapid start-up when the temperature is raised during start-up of the fuel cell.

  An object of the present invention is to provide a start-up system and a start-up that enable rapid start-up while suppressing thermal stress generated in the cell when the temperature of the fuel cell is raised to the operating temperature during operation of the solid oxide fuel cell power generation system. It is to provide a method.

  The present invention is an activation system that raises the temperature of a fuel cell to an operating temperature during operation of a power generation system including a fuel cell that is an assembly of solid oxide cells, and is an assembly of solid oxide cells. An anode heating gas generator for generating an anode heating gas to be supplied to the anode of the cell when raising the temperature of the fuel cell to an operating temperature, and a cathode heating gas for generating a cathode heating gas to be supplied to the cathode of the cell A generator, a control device for controlling the operating state of the anode heating gas generator and the cathode heating gas generator, and an anode temperature measuring means for measuring the temperature of the anode in the control device, The cathode temperature measuring means for measuring the cathode temperature, the anode temperature measuring means, and the cathode temperature measuring means, respectively. Cell average temperature estimating means for estimating cell average temperature based on node temperature and cathode temperature; cell average temperature estimated by said cell average temperature estimating means; said anode temperature and said cathode temperature based on said anode temperature and said cathode temperature; Thermal stress estimating means for estimating the surface thermal stress of the anode, the operating state of the anode heating gas generator according to the surface thermal stress of the anode and the surface thermal stress of the cathode estimated by the thermal stress estimating means, and the A starting system for a solid oxide fuel cell power generation system is provided with thermal stress control means for adjusting at least one of operating states of a cathode heating gas generator.

  ADVANTAGE OF THE INVENTION According to this invention, when heating up a fuel cell to operating temperature at the time of starting of a solid oxide form fuel cell power generation system, rapid starting which suppressed the thermal stress which generate | occur | produces in a cell to below an allowable value is attained. Since the generation of thermal stress in the cell can be suppressed, the durability of the cell can also be improved.

  The present invention also relates to a method for raising the temperature of the fuel cell to an operating temperature during operation of a power generation system including a fuel cell that is an assembly of solid oxide cells, the assembly comprising solid oxide cells. An anode heating gas generator for generating an anode heating gas supplied to the anode of the cell in a fuel cell, a cathode heating gas generator for generating a cathode heating gas supplied to the cathode of the cell, and the anode An anode temperature measuring step for measuring the temperature of the anode by the control device; and a cathode for measuring the temperature of the cathode. Temperature measurement step, anode temperature measurement step, and anode temperature measurement step and cathode temperature measurement step. A cell average temperature estimating step for estimating a cell average temperature based on the cathode temperature, and a surface heat of the anode and the cathode based on the cell average temperature estimated in the cell average temperature estimating step, the anode temperature, and the cathode temperature. A thermal stress estimation step for estimating stress, an operating state of the anode heating gas generator and cathode heating gas generation according to the surface thermal stress of the anode and the surface thermal stress of the cathode estimated in the thermal stress estimation step In the solid oxide fuel cell power generation system starting method, the thermal stress control step for adjusting at least one of the operating states of the apparatus is sequentially executed.

  The present invention also provides an activation system for raising the temperature of the fuel cell to an operating temperature during operation of a power generation system including a fuel cell that is an assembly of solid oxide cells, the anode being supplied to the anode of the cell An anode heating gas generator for generating a heating gas, a cathode heating gas generator for generating a cathode heating gas to be supplied to the cathode of the cell, the anode heating gas generator, and the cathode heating gas generator A control device for controlling the operating state of the device, the control device comprising: an anode gas temperature measuring means for measuring the gas temperature of the anode; a cathode gas temperature measuring means for measuring the gas temperature of the cathode; Based on the anode gas temperature and the cathode gas temperature respectively measured by the anode gas temperature measuring means and the cathode gas temperature measuring means. Cell average temperature estimating means for estimating the cell average temperature, and the surface thermal stresses of the anode and the cathode based on the cell average temperature estimated by the cell average temperature estimating means, the anode gas temperature and the cathode gas temperature. A thermal stress estimating means to estimate, an operating state of the anode heating gas generator and the cathode heating gas generation according to the surface thermal stress of the anode and the surface thermal stress of the cathode estimated by the thermal stress estimating means The start-up system in a solid oxide fuel cell power generation system is provided with a thermal stress control means for adjusting at least one of the operation states of the apparatus.

  The present invention also relates to a method for heating the fuel cell to an operating temperature during operation of a power generation system including a fuel cell that is an assembly of solid oxide cells, the anode heating being supplied to the anode of the cell An anode heating gas generator for generating a gas, a cathode heating gas generator for generating a cathode heating gas to be supplied to the cathode of the cell, an anode heating gas generator, and a cathode heating gas generator. An anode gas temperature measuring step for measuring the anode gas temperature, a cathode gas temperature measuring step for measuring the cathode gas temperature, and the anode gas temperature. Based on the anode gas temperature and cathode gas temperature measured in the measurement step and the cathode gas temperature measurement step, respectively. A cell average temperature estimating step for estimating the cell average temperature, and estimating the surface thermal stress of the anode and the cathode based on the cell average temperature estimated in the cell average temperature estimating step, the anode gas temperature, and the cathode gas temperature. A thermal stress estimation step, and an operating state of the anode heating gas generator and an operation of the cathode heating gas generator according to the surface thermal stress of the anode and the surface thermal stress of the cathode estimated in the thermal stress estimation step. A starting method for a solid oxide fuel cell power generation system, wherein a thermal stress control step for adjusting at least one of the states is sequentially executed.

  In addition, it is desirable to use a burner, an electric heater, a heat exchanger, or the like for the anode heating gas generator and the cathode heating gas generator.

  Hereinafter, embodiments of the present invention will be described. However, it is not limited to the following embodiment.

  First, the configuration of the start-up system in the solid oxide fuel cell power generation system according to the embodiment of the present invention will be described with reference to FIG. In addition, as a cell structure of a solid oxide fuel cell, a cylindrical type and a flat plate type are mainly proposed, but both have the same basic operating principle. In the following embodiments, a cylindrical type is taken as an example. I will explain.

  FIG. 1 is a configuration diagram for explaining a starting method of a fuel cell power generation system according to an embodiment of the present invention. First, the operation of the fuel cell device main body 100 will be described.

  When starting the fuel cell, the cathode heating combustion gas 2 from the cathode burner 1 is sent to the cathode gas header 3. The cathode heating combustion gas sent to the cathode gas header 3 descends the gas introduction pipe 4 and is supplied to the lower part 5 in the cell, and then heats the cell from the inside of the cathode while ascending in the cell. Further, when the fuel cell is started, the anode heating combustion gas 7 from the anode burner 6 is sent to the anode gas chamber 9 located below the cell stack 8. The anode heating combustion gas sent to the anode gas chamber 9 heats the cell from the outside of the anode while rising between the cells. The two combustion gases contribute to heating from the inner and outer surfaces of the cell, then merge at the cell outlet and are discharged as exhaust gas 10 from the exhaust port 12 provided in the battery storage chamber 11.

Methane can be used as the fuel for the two burners and is supplied from a common fuel tank 13. Combustion air is also supplied from a common blower 14. Here, the flow rates (F _FC and F _AC ) of the fuel 15 and the combustion air 16 are adjusted so that the cathode burner 1 maintains air-rich combustion. Further, the flow rates (F _FA and F _AA ) of the fuel 17 and the combustion air 18 are adjusted so that the anode burner 6 becomes rich in fuel. For example, a fuel-air ratio of 0.65, which is the ratio of fuel to air, is adopted for the cathode burner 1, and a fuel-air ratio of 1.1 is adopted for the anode burner 6. The cathode burner 1 is supplied with gas temperature adjusting air 19, and the anode burner 6 is supplied with gas temperature adjusting nitrogen 20 from a nitrogen tank 21. These flow rates are indicated by F _A and F _N.

Heating state of the cell during boot is measured by the cathode thermometer 22 and the anode thermometer 23, the measurement signal of the measurement signal 24 and the anode temperature T _A of the measured cathode temperature T _C is sent to the control unit 200 will be described later . Further, as the operation signal from the control device 200, the flow rate adjusting valves 26, 27, 28, 29, 30, and 31 for determining the flow rates F _FC , F _AC , F _A , F _FA , F _AA , and F _N are shown. Opening signals (A _FC , A _AC , A _A , A _FA , A _AA , A _N ) are output.

  In addition, although electric power is taken out from the collector electrode 32 installed in the edge part of the cell stack 8 at the time of the electric power generation driving | operation of a battery, only a starting method is demonstrated here and the description regarding the electric power generation is abbreviate | omitted.

  Next, the function and operation of the control device 200 will be described. Here, in order to facilitate understanding of the operation of the control device, each control element is shown as a block. However, in actuality, it is realized by a controller disposed in the same package as the fuel cell device main body 100 or in the vicinity thereof. .

First, the basic function will be described. The control device 200, the average cell temperature estimating means 210, based on a cathode temperature T _C and the measurement signal 25 of the anode thermometer 23 is the measurement signal 24 of the cathode thermometer 22 anode temperature T _A, the thickness direction of the cell Estimate internal temperature distribution. Then, the cell internal volume average temperature T _M (hereinafter simply referred to as cell average temperature) that changes every moment during the temperature rise is estimated from the temperature distribution in the thickness direction of the cell, and this is output as the cell average temperature signal 33.

Next, in the thermal stress estimation means 220, the cathode surface thermal stress S _C (hereinafter simply referred to as the cathode thermal stress) and the anode surface thermal stress S based on the cell average temperature T _M , the cathode temperature T _C and the anode temperature T _{A. A} (hereinafter simply referred to as anode thermal stress) is estimated, and these are output as a cathode thermal stress signal 34 and an anode thermal stress signal 35. These thermal stresses S _C and S _A also change every moment during the temperature rise.

Furthermore the thermal stress control unit 230, based on the cathode thermal stress S _C and the anode thermal stress S _A, for adjusting the combustion state of the cathode burner operation amount K _C and the anode burner 6 for adjusting the combustion state of the cathode burner 1 determining the anode burner operation amount K _a. And it outputs as a cathode burner operation signal 36 and an anode burner operation signal 37, respectively. That is, both the cathode thermal stress S _C and the anode thermal stress S _A is as always equal to or less than the allowable value, determines a manipulated variable K _C and K _A during heated. The detailed meanings of the manipulated variables K _C and K _A will be described later.

In the cathode burner control means 240, each opening degree A _FC , A _{AC of} the flow rate adjusting valves 26, 27, 28 required for generating the cathode heating combustion gas 2 to be sent to the gas header 3 based on the cathode burner operation amount K _C. A Opening degree signals 41, 42 and 43 for defining _A are output. Similarly, in the anode burner control unit 250, based on the anode burner operation amount K _A, the opening of flow control valve 2,30,31 necessary for generating the anode heating combustion gas 7 to be sent to the anode gas chamber 9 and it outputs the opening degree signal 51, 52, 53 defining the _{a FA, a AA, a N} .

  The operation of the control device 200 described above will be described more specifically with reference to FIGS.

First, the cell average temperature estimation unit 210 and the thermal stress estimation unit 220 will be described with reference to FIG. The cathode inner surface 38 and the anode outer surface 39 shown in FIG. 2 are exposed to the cathode heating combustion gas 2 and the anode heating combustion gas 7, respectively, and the cell is heated from both sides. In the cell the average temperature estimating section 210, using the cathode temperature T _C and the anode temperature T _A is a measured value, determine the temperature distribution in the cell thickness direction by carrying out the heat transfer calculations. As shown in the drawing, in this embodiment, the virtual temperature is divided into five concentric cylinders, and the respective cylinder temperatures T ₁ , T ₂ ,... T ₅ are obtained. Based on the temperature distribution determined here, it obtains the volume average temperature in consideration of the volume of each cylinder, which is the estimated value of the cell average temperature T _M. The above number of divisions is considering practical estimation accuracy of the cell average temperature T _M, it may be selected arbitrarily. Next, the thermal stress estimation means 220 uses the cell average temperature T _M , the cathode temperature T _C, and the anode temperature T _A , and the cathode thermal stress S _C and the anode thermal stress S according to the formulas (1) and (2). _A is estimated.

S _C = (T _M −T _C ) · A · E / (1-ν) (1)
S _A = (T _M −T _A ) · A · E / (1-ν) (2)
Here, A, E, and ν are material property values of the cell, and are a linear expansion coefficient, Young's modulus, and Poisson's ratio, respectively. During normal cell heating, average cell temperature T _M is delayed rises above the cathode temperature T _C and the anode temperature T _A. Moreover, since the formula (1) and Poisson's ratio being used in the expression (2) ([nu) is smaller than 1, the cathode thermal stress S _C both anode thermal stress S _A becomes a negative value, both compressive stress ( Stress in the direction of the arrow in the figure occurs. However, if there is a large difference in the cathode temperature T _C and the anode temperature T _A is not necessarily such. For example, the cathode gas temperature T _GC is significantly higher than the anode gas temperature T _GA, if a rise in the cathode temperature T _C precedes significantly as compared to the anode temperature T _A, the anode temperature than the cell average temperature T _M T _a sometimes becomes low, in this case the anode thermal stress S _a becomes a positive value, the tensile stress.

  Next, the thermal stress control means 230 is demonstrated using FIG. 3 and FIG.

FIG. 3 shows the flow rates F _FC , F _AC , F _FA , F _AA at start-up and their minimum and maximum values. Maximum value _{F Amax} of the minimum value _{F fcmin} and _{F A} of F _FC is fuel flow rate and gas temperature adjusting air flow rate of the cathode burner 1 at the start of _activation, the maximum value F minimum value _{F FA min} and _{F N} of _{F FA Amax} is the fuel flow rate of the anode burner 6 and the nitrogen flow rate for gas temperature adjustment at the start of startup (t ₀ ). Further, the maximum value F _{FCmax of} F _FC and the minimum value F _Amin of F _A are the fuel flow rate and the gas temperature adjusting air flow rate of the cathode burner 1 at the end of startup (t ₁ ), and the maximum value F _{FAmax of} F _FA The minimum value F _Amin of F _N is the fuel flow rate of the anode burner 6 and the nitrogen flow rate for adjusting the gas temperature after the start-up. In this case, the flow rate at the start of startup (t ₀ ) is selected so that the temperature is sufficiently low so that the cell is not subjected to thermal shock by the combustion gas from the cathode burner 1 and the anode burner 6. In addition, the flow rate at the end of start-up (t ₁ ) is selected to be sufficiently high so that it can be heated to the cell temperature necessary for shifting to power generation operation. As described above, the cathode combustion air flow rate F _AC and the anode combustion air flow rate F _AA have a fuel-air ratio of 0.65 for the cathode burner 1 and a fuel-air ratio of 1.1 for the anode burner 6, respectively. In this way, they are determined by linking to the cathode fuel flow rate F _FC and the anode fuel flow rate F _FA , respectively.

Here, to expect the thermal stress control means 230 is a proper value of the cathode burner operation amount K _C and the anode burner operation amount K _A, starts at the beginning of (t ₀₎ until the start end (t ₁₎ The flow rates F _FC , F _AC , F _FA , and F _AA are determined. In FIG. 3, the case where the fuel flow rate is switched at a constant speed (referred to herein as the constant speed switching method) is indicated by a broken line, but this constant speed switching method is not necessarily optimal when considering the thermal stress generated in the cell. .

Figure 4 is the thermal stress control unit 230 indicates the determination method of the cathode burner operation amount K _C and the anode burner operation amount K _A. As illustrated, the cathode burner operation amount K _C is a deviation [Delta] S _C by adding the cathode thermal stress S _C and the preset thermal stress limit value S _L in addition means 231, a proportional-integral-derivative it The calculation is performed by the calculation means (PID) 232. Here, the reason for using the adding means 231 for obtaining the difference [Delta] S _C is while giving a thermal stress limit value S _L a positive value, S _C is often a negative value in normal startup Therefore, when the thermal stress tolerance is considered, it is added in the calculation. The value range of the manipulated variable K _C is 0 to 1, and K _C = 0 at the start of activation (t ₀ ).

Similarly, the anode burner operation amount K _A, a deviation [Delta] S _A by adding at the thermal stress limit value S _L and the anode thermal stress S _A a summing means 235 which is set in advance, a proportional integral derivative calculation means this ( PID) 236 to calculate. Here again, the reason why the adding means 235 is used to determine the deviation ΔS _A is the same as that for determining the cathode burner operation amount K _C. Also in this case, the range of the operation amount K _A is 0 to 1, and K _A = 0 at the start of activation (t ₀ ).

In this manner, when using a starting method for determining the cathode burner operation amount K _C and the anode burner operation amount K _A, the both the cathode thermal stress S _C and the anode thermal stress S _A generated by all activated process reliably limit It can be as follows. Furthermore, since the thermal stress limitation can be used effectively, an effect that the start-up can be completed promptly can be expected.

  Next, the cathode burner control means 240 and the anode burner control means 250 will be described with reference to FIG.

First, the cathode burner control means 240 will be described. First, the operation means 241, 242 and 243 receives a cathode burner operation amount _{K C} as determined by the thermal stress control means 230, respectively fuel flow _{F FC,} the combustion air flow _{F AC,} gas temperature adjusting air flow _{F A} To decide. Next, these _{F FC,} F AC, the flow rate control valve 26, 27, 28 and _{F A} degree _{A FC,} A AC, in order to convert _{A A,} using respective valve characteristic function 244, 245 and 246 . Similarly, the anode burner control unit 250, firstly, the calculating means 251, 252, and 253 receives the anode burner operation amount _{K A,} which is determined by the thermal stress control means 230, respectively fuel flow _{F FA,} combustion air flow F _AA , gas temperature adjusting air flow rate _FN is determined. Next, in order to convert these F _FA , F _AA , and F _N into the valve openings A _FA , A _AA , and A _N of the flow rate adjusting valves 29, 30, and 31, valve characteristic functions 254, 255, and 256 are used, respectively. .

As described above, the cathode combustion air flow F _AC and the anode combustion air flow F _AA have a fuel / air ratio of 0.65 for the cathode burner 1 and a fuel / air ratio of 1.1 for the anode burner 6; The calculation means 242 and the calculation means 252 are determined by linking to the cathode fuel flow rate F _FC and the anode fuel flow rate F _FA , respectively. The proportionality constants at this time are _KBC and _KBA .

  Next, the starting characteristics of the solid oxide fuel cell power generation system according to the embodiment of the present invention will be described with reference to FIG.

The solid line in the figure shows the activation results when the cathode burner operation amount K _C and the anode burner operation amount K _A was determined by the thermal stress control by the activation method of the invention described above, the broken line in above the K _C and K _A The start result when such a constant speed switching method is adopted is shown. As it can be seen from FIG. 6, when the constant speed switching, there are times when the cathode thermal stress S _C exceeds the limit value S _L in initial start-up stage, the anode thermal stress S _A reversed relative to the limiting value S _L Tolerance is great. In contrast, in the case of the thermal stress control of the present invention is to provide a cathode thermal stress S _C both anode thermal stress S _A exceeds the limit value S _L, moreover, at time t ₂ while effectively utilizing this The startup is finished promptly. As a result, the start-up time is significantly shortened (t ₁ -t ₂ ) compared to the case of the constant speed switching method.

  As described above, according to the present invention, rapid start-up is possible in which the thermal stress generated in the cell at the time of significant temperature rise at start-up is suppressed to an allowable value or less, and the durability of the cell in the solid oxide fuel cell power generation system Can be improved.

  In addition, this invention is not limited to the above-mentioned embodiment, It can apply, without changing the essence in the embodiment described below.

  First, it is the position of the cell that should be noted as thermal stress, that is, the temperature measurement position, but basically focus on the position where the thermal stress generated during startup is the highest, or the position where the material strength due to thermal stress is a problem. This is desirable and is not limited to the embodiments of the present invention. This basic concept is the same not only for the axial position of the cell but also for which cell in the cell stack.

  Further, in the embodiment of the present invention, the position of the cell to be noted as thermal stress is set to one location. However, when the magnitude relationship between the thermal stresses at a plurality of locations fluctuates during startup, the position to be noted is selected. A method may be used in which a plurality of locations are set up and activated while paying attention to the value having the smallest thermal stress tolerance.

  Furthermore, in the embodiment of the present invention, the thermal stress is estimated by measuring the cell temperature, that is, the cathode surface temperature and the anode surface temperature, but the gas temperature in the vicinity of each surface is measured, and this is determined as the surface temperature. It is good also as a method of estimating thermal stress by considering.

  In the embodiment of the present invention, a cylindrical cell is used. However, the present invention is not necessarily limited to this, and the present invention can be applied to various cells such as a flat plate type and a disk type without changing the essence of the present invention. .

  In the embodiment of the present invention, methane is used as the fuel for the cell heating burner, but various fuels such as hydrogen, city gas, LNG, and kerosene can be selectively used depending on the cell material. Even in this case, the essence of the present invention can be implemented without any change.

  Furthermore, in the embodiment of the present invention, the heating method is performed from both the cathode and the anode. However, even when a heating method is employed from only one of the cathodes and the anodes, the present invention can of course be implemented without changing the essence of the present invention. .

In the embodiment of the present invention, the common limit value _SL is used for the thermal stress generated in the cathode and the anode at start-up, but the strength of the cathode and the anode may be different depending on the material constituting the cell. Even in this case, the thermal effect control may be performed for the limit value set individually, and can be performed without changing the essence of the present invention.

  In the embodiment of the present invention, the fuel / air ratio of the cathode burner is set to 0.65 and the fuel / air ratio of the anode burner is set to 1.1. However, this fuel / air ratio is not necessarily required depending on the material constituting the cell. Absent. In short, as long as the fuel / air ratio is 1 or less in a cathode that is preferred to operate in an oxidizing atmosphere and the fuel / air ratio is 1 or more in an anode that is preferred to operate in a reducing atmosphere, the burner structure and various design criteria are used. An appropriate fuel-air ratio can be selected in consideration.

  In the above embodiment, the burner combustion gas is used for heating the cathode or the anode. However, it is not always necessary to use the burner. For example, the heating gas is indirectly supplied using an electric heater or a heat exchanger. May be generated.

  As described above, according to the present invention, it is possible to safely and quickly raise the temperature from room temperature to about 600 ° C. at which power can be generated at the time of start-up, greatly shortening the start-up time and improving the durability of the cell. can do.

  When the cell is heated to a predetermined operating temperature, combustion by the anode burner and the cathode burner is stopped, power generation gas, that is, fuel gas is supplied to the anode, and air as an oxidant is supplied to the cathode. To start power generation.

It is a figure for demonstrating the starting method in the fuel cell power generation system of this invention. It is a figure for demonstrating the cell average temperature estimation means and thermal-stress estimation means in the control apparatus of a starting system. It is a figure for demonstrating the thermal-stress control means in a control apparatus with the following FIG. It is a figure for demonstrating the thermal-stress control means in a control apparatus combined with previous FIG. It is a figure for demonstrating the cathode burner control means and anode burner control means in a control apparatus. It is a figure for demonstrating the starting characteristic by the starting method of the fuel cell power generation system by embodiment of this invention, especially a starting time shortening effect.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cathode burner, 2 ... Cathode heating combustion gas, 3 ... Cathode gas header, 4 ... Gas introduction pipe, 5 ... Lower part in cell, 6 ... Anode burner, 7 ... Anode heating combustion gas, 8 ... Cell stack, 9 DESCRIPTION OF SYMBOLS ... Anode gas chamber, 10 ... Exhaust gas, 11 ... Battery storage chamber, 12 ... Exhaust port, 13 ... Fuel tank, 14 ... Blower, 15 ... Fuel, 16 ... Combustion air, 17 ... Fuel, 18 ... Combustion air, 19 Gas for adjusting gas temperature, 20 Nitrogen for adjusting gas temperature, 21 Nitrogen tank, 22 Cathode thermometer, 23 Anode thermometer, 24 Measurement signal, 25 Measurement signal, 26 Flow control valve, 27 Flow adjustment valve, 28 ... Flow adjustment valve, 29 ... Flow adjustment valve, 30 ... Flow adjustment valve, 31 ... Flow adjustment valve, 32 ... Collector, 33 ... Cell average temperature signal, 34 ... Cathode thermal stress signal, 35 ... Anode Thermal stress 36, cathode burner operation signal, 37 ... anode burner operation signal, 38 ... cathode inner surface, 39 ... anode outer surface, 41 ... opening signal, 42 ... opening signal, 43 ... opening signal, 51 ... opening signal, 52... Opening signal, 53... Opening signal, 100. Means (PID), 235... Addition means, 236... Proportional integral derivative operation means (PID), 240... Cathode burner control means, 241. ... Valve characteristic function, 246 ... Valve characteristic function, 250 ... Anode burner control means, 251 ... Calculation means, 252 ... Calculation means, 253 ... Calculation means, 254 ... Valve characteristic function 255 ... valve characteristic function, 256 ... valve characteristic function.

Claims (4)

A startup system that raises the temperature of the fuel cell to an operating temperature during operation of a power generation system including a fuel cell that is an assembly of solid oxide cells,
An anode heating gas generator for generating an anode heating gas supplied to the anode of the cell, a cathode heating gas generator for generating a cathode heating gas supplied to the cathode of the cell, and the anode heating gas generation And a control device for controlling the operating state of the cathode heating gas generator,
The control device includes an anode temperature measuring means for measuring the temperature of the anode, a cathode temperature measuring means for measuring the temperature of the cathode, and anode temperatures measured by the anode temperature measuring means and the cathode temperature measuring means, respectively. A cell average temperature estimating means for estimating a cell average temperature based on the cathode temperature; a cell average temperature estimated by the cell average temperature estimating means; the anode temperature; and a surface heat of the anode and the cathode based on the cathode temperature. Thermal stress estimation means for estimating stress, operating state of the anode heating gas generator according to the surface thermal stress of the anode estimated by the thermal stress estimation means and the surface thermal stress of the cathode, and the cathode heating A thermal stress control means for adjusting at least one of the operating states of the gas generator is provided. Activation system in the solid oxide fuel cell power generation system. A method of raising the temperature of the fuel cell to an operating temperature during operation of a power generation system including a fuel cell that is an assembly of solid oxide cells,
An anode heating gas generator for generating an anode heating gas supplied to the anode of the cell, a cathode heating gas generator for generating a cathode heating gas supplied to the cathode of the cell, and the anode heating gas generation A control device for controlling the operating state of the apparatus and the cathode heating gas generator,
In the control device, an anode temperature measuring step for measuring the anode temperature, a cathode temperature measuring step for measuring the cathode temperature, an anode temperature and a cathode measured in the anode temperature measuring step and the cathode temperature measuring step, respectively. A cell average temperature estimating step for estimating a cell average temperature based on the temperature; and a cell average temperature estimated in the cell average temperature estimating step, a surface thermal stress of the anode and the cathode based on the anode temperature and the cathode temperature. A thermal stress estimation step to be estimated; an operating state of the anode heating gas generator and the cathode heating gas generator according to the surface thermal stress of the anode and the surface thermal stress of the cathode estimated in the thermal stress estimation step; Thermal stress control to adjust at least one of the operating conditions Starting in the solid oxide fuel cell power generation system is characterized in that so as to perform the step sequentially. A startup system that raises the temperature of the fuel cell to an operating temperature during operation of a power generation system including a fuel cell that is an assembly of solid oxide cells,
An anode heating gas generator for generating an anode heating gas supplied to the anode of the cell, a cathode heating gas generator for generating a cathode heating gas supplied to the cathode of the cell, and the anode heating gas generation And a control device for controlling the operating state of the cathode heating gas generator,
The control device includes an anode gas temperature measuring means for measuring the anode gas temperature, a cathode gas temperature measuring means for measuring the cathode gas temperature, an anode gas temperature measuring means and the cathode gas temperature measuring means, respectively. A cell average temperature estimating means for estimating a cell average temperature based on the measured anode gas temperature and cathode gas temperature, and the cell average temperature estimated by the cell average temperature estimating means, the anode gas temperature, and the cathode gas temperature. Thermal stress estimating means for estimating the surface thermal stress of the anode and the cathode based on the thermal stress estimating means, and the anode heating gas according to the surface thermal stress of the anode and the surface thermal stress of the cathode estimated by the thermal stress estimating means At least one of an operating state of the generator and an operating state of the cathode heating gas generator Activation system in the solid oxide fuel cell power generation system comprising the thermal stress control means for adjusting. A method of raising the temperature of the fuel cell to an operating temperature during operation of a power generation system including a fuel cell that is an assembly of solid oxide cells,
An anode heating gas generator for generating an anode heating gas supplied to the anode of the cell, a cathode heating gas generator for generating a cathode heating gas supplied to the cathode of the cell, and the anode heating gas generation A control device for controlling the operating state of the apparatus and the cathode heating gas generator,
The control device includes an anode gas temperature measurement step for measuring the anode gas temperature, a cathode gas temperature measurement step for measuring the cathode gas temperature, an anode gas temperature measurement step, and a cathode gas temperature measurement step, respectively. A cell average temperature estimating step for estimating a cell average temperature based on the measured anode gas temperature and cathode gas temperature, and a cell average temperature estimated in the cell average temperature estimating step based on the anode gas temperature and the cathode gas temperature. A thermal stress estimating step for estimating the surface thermal stress of the anode and the cathode; and a gas generator for heating the anode according to the surface thermal stress of the anode and the surface thermal stress of the cathode estimated in the thermal stress estimation step. Operating state and operation of the cathode heating gas generator Starting the solid oxide fuel cell power generation system is characterized in that so as to sequentially perform heat stress control step of adjusting at least one of the states.

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