JP2020013720A - Fuel cell system, flow measuring method of material gas, and gas type specification method of material gas - Google Patents

Abstract

To restrain output drop or durability deterioration of a fuel cell system, even when the constitution of raw fuel gas changes.SOLUTION: A fuel cell system includes: a fuel cell generating electricity by electrochemical reaction of anode gas and cathode gas; a reformer for reforming the raw fuel gas and producing the anode gas; multiple flowmeters for detecting flow of raw fuel gas supplied to the reformer, respectively; and an arithmetic processing section for calculating the flow of raw fuel gas on the basis of the detection values from the multiple flowmeters, where the multiple flowmeters are configured so that the deviation of the detection value from the true value of each flow changes according to the constitution of the raw fuel gas and the characteristics of the change in deviation from the constitution are different from each other, and the arithmetic processing section calculates the deviation of at least any one flowmeter on the basis of the characteristics of the multiple flowmeters and the detection values, and calculates the flow of the raw material gas from the calculated deviation and the detection value of at least any one flowmeter.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a fuel cell system including a fuel cell that generates power by an electrochemical reaction between an anode gas and a cathode gas, a method for measuring a flow rate of a raw fuel gas of an anode gas, and a method for specifying a gas type.

  Conventionally, a hydrogen generation unit that generates a hydrogen-containing gas (anode gas) from a hydrogen-containing fuel (raw fuel gas), a cell stack that generates power using the hydrogen-containing gas, and a fuel stack that is supplied to the hydrogen generation unit A fuel flow meter that obtains the supply amount, a sensor that detects oxygen or nitrogen in the fuel on the upstream side of the hydrogen generator, and an error included in the value from the fuel flow meter is corrected based on the detection result of the sensor. There is known a fuel cell system that includes a correction unit that obtains a supply amount of fuel containing air (see, for example, Patent Document 1). In this fuel cell system, even when the hydrogen-containing fuel is supplied to the hydrogen generator in a state where the air is mixed, the supply amount of the hydrogen-containing fuel can be appropriately adjusted according to the mixed amount of the air. it can. Conventionally, as a fuel treatment system for a fuel cell that converts a raw fuel (raw fuel gas) containing hydrocarbons, alcohols or ethers and a raw water or steam into a hydrogen-rich fuel gas (anode gas), a fuel gas has been used. There is known a device including a dew point temperature measuring unit, a calculating unit for estimating a raw fuel flow rate based on a dew point temperature, and a flow rate adjusting unit for adjusting a raw fuel flow rate based on a calculation result (for example, see Patent Document 2). . According to this fuel processing system, stable operation of the fuel cell and protection of the system can be achieved even when the flow rate of the raw fuel or the raw water (steam) deviates from the set value for an unintended reason.

JP 2012-169214 A Japanese Patent No. 4038390

  As a raw fuel gas for the anode gas of the fuel cell as described above, a city gas or a propane gas containing a combustible component such as methane, ethane, propane, and butane is generally used. Concentration ratio) differs depending on the gas company, the region (the place of origin of the gas), and the like, and the composition (gas type) of the raw fuel gas may change with time depending on the region. When the composition (gas type) of the raw fuel gas supplied to the fuel cell system changes, an error in the detection value of the fuel flow meter increases in accordance with the change in the composition, and the raw fuel gas (heat quantity) becomes insufficient. Therefore, there is a possibility that the output of the fuel cell system may be reduced, or the durability may be reduced due to an increase in temperature due to an oversupply of the raw fuel gas. However, in the techniques described in Patent Documents 1 and 2, no change in the composition of the raw fuel gas is considered.

  Thus, the present disclosure has a main object of suppressing a decrease in output and a decrease in durability of a fuel cell system even when the composition of a raw fuel gas changes.

  The fuel cell system of the present disclosure is a fuel cell system including a fuel cell that generates power by an electrochemical reaction between an anode gas and a cathode gas, and a reformer that reforms a raw fuel gas to generate the anode gas. A plurality of flow meters each detecting a flow rate of the raw fuel gas supplied to the reformer, wherein a deviation amount of a detected value from a true value of the flow rate changes according to a composition of the raw fuel gas. A plurality of flowmeters configured as described above and having different characteristics of a change in the deviation amount with respect to the composition, and at least one of the flowmeters based on the characteristics and the detected values of the plurality of flowmeters Calculating the shift amount of the raw fuel gas supplied to the reformer from the calculated shift amount and the detection value of the at least one of the flow meters. It is intended to include an arithmetic processing unit for calculating the flow rate.

  The fuel cell system according to the present disclosure includes a plurality of flow meters each detecting a flow rate of a raw fuel gas supplied to a reformer, and a raw fuel supplied to the reformer based on detection values of the plurality of flow meters. An arithmetic processing unit for calculating a gas flow rate. Each flow meter is configured such that the amount of deviation of the detected value with respect to the true value of the flow rate changes in accordance with the composition of the raw fuel gas. The characteristics of the shift amount change are different from each other. That is, the plurality of flow meters basically output different values as the flow rate of the raw fuel gas having a certain composition, and the difference between the detection values of the plurality of flow meters is determined by the plurality of flow meters determined according to each characteristic. Is equal to the difference between the amounts of deviation of the detection values with respect to the true value of. Therefore, it is possible to calculate the amount of deviation of the detected value with respect to the true value of at least one of the flow meters based on the characteristics and the detected values of the plurality of flow meters, and the calculated amount of deviation and at least one of the at least one From the detected value of the flow meter, the flow rate of the raw fuel gas supplied to the reformer can be accurately calculated. Thereby, in the fuel cell system of the present disclosure, even when the composition of the raw fuel gas changes, the flow rate of the raw fuel gas supplied to the reformer can be accurately acquired by the arithmetic processing unit. Therefore, it is possible to accurately supply the anode gas as required from the reformer to the fuel cell. As a result, even when the composition of the raw fuel gas changes, it is possible to favorably suppress a decrease in output and durability of the fuel cell system due to an excess or deficiency of the raw fuel gas. In addition, the fuel cell system may include two flow meters, may include three or more flow meters, and may use three or more flow meters. The accuracy of the calculated flow rate of the raw fuel gas can be further improved.

  Further, for each of the plurality of flow meters, a specific heat difference between a standard gas, which is the raw fuel gas whose composition is known, and the raw fuel gas supplied to the reformer, and the deviation amount. A function indicating a relationship may be defined, and the arithmetic processing unit calculates the specific heat difference based on the functions and the detected values of the plurality of flow meters, and calculates the calculated specific heat difference and the at least one of the specific heat differences. The deviation amount may be calculated from the function of one flow meter. That is, the specific heat of the raw fuel gas has a correlation with the composition of the raw fuel gas (the concentration of the combustible component), and the specific heat difference between the standard gas and the raw fuel gas supplied to the reformer is the raw fuel gas. It changes according to the difference in composition between the gas and the standard gas. Therefore, it is possible to define a function indicating the relationship between the specific heat difference and the amount of deviation for each of the plurality of flow meters, and by calculating the specific heat difference based on the functions and the detection values of the plurality of flow meters, From the specific heat difference and at least one of the functions of the flow meter, the amount of deviation of the detected value from the true value of the flow meter can be accurately calculated.

  Further, the arithmetic processing unit may calculate the specific heat difference from a difference between the detection values of the plurality of flow meters and a difference between the deviation amounts obtained from the function. This makes it possible to accurately calculate the specific heat difference between the standard gas and the raw fuel gas supplied to the reformer.

  Further, the arithmetic processing unit may specify a gas type of the raw fuel gas supplied to the reformer based on the specific heat difference and the specific heat of the standard gas. That is, the specific heat of the raw fuel gas has a correlation with the composition of the raw fuel gas (the concentration of the combustible component), and can be obtained from the specific heat difference and the specific heat of the standard gas. Therefore, by calculating the specific heat difference, the gas type of the raw fuel gas can be accurately specified from the specific heat difference and the specific heat of the standard gas. Then, by reflecting the specified gas type of the raw fuel gas in the control of the fuel cell system, it becomes possible to maintain good performance and durability of the fuel cell.

  Further, the fuel processing system may include a raw fuel gas pump that supplies the raw fuel gas to the reformer, and a pump control unit that controls the raw fuel gas pump. Setting a target flow rate of the raw fuel gas from a calorific value corresponding to the target current value of the fuel cell and the gas type of the raw fuel gas, and a flow rate of the raw fuel gas calculated by the arithmetic processing unit. The raw fuel gas pump may be controlled to match the target flow rate. Thereby, the flow rate of the raw fuel gas can be accurately calculated, and the target flow rate of the raw fuel gas can be set more appropriately according to the gas type (composition) of the raw fuel gas supplied to the reformer. Therefore, it is possible to more accurately supply the anode gas as required from the reformer to the fuel cell.

  A method for measuring a flow rate of a raw fuel gas according to the present disclosure is a method for measuring a flow rate of a raw fuel gas supplied to a reformer that generates an anode gas of a fuel cell, wherein the flow rate of the raw fuel gas is measured. The reforming is performed by a plurality of flowmeters in which a deviation amount of a detected value with respect to a true value is configured to change in accordance with a composition of the raw fuel gas and a characteristic of a variation in the deviation amount with respect to the composition is different from each other. Detecting the flow rate of the raw fuel gas supplied to the flowmeter, calculating the deviation amount of at least one of the flow meters based on the characteristics and the detected values of the plurality of flow meters, and calculating the calculated deviation amount. The flow rate of the raw fuel gas supplied to the reformer is calculated from the amount and the detected value of the at least one of the flow meters.

  According to such a method, even when the composition of the raw fuel gas changes, the flow rate of the raw fuel gas supplied to the reformer can be obtained with high accuracy. Anode gas can be supplied with high accuracy as required. As a result, even when the composition of the raw fuel gas changes, it is possible to favorably suppress a decrease in output and durability of the fuel cell system due to an excess or deficiency of the raw fuel gas.

  Another fuel cell system according to the present disclosure includes a fuel cell that generates power by an electrochemical reaction between an anode gas and a cathode gas, and a reformer that reforms a raw fuel gas to generate the anode gas. In the plurality of flowmeters each detecting the flow rate of the raw fuel gas supplied to the reformer, the deviation amount of the detection value with respect to the true value of the flow rate according to the composition of the raw fuel gas A plurality of flow meters configured to change and the characteristics of the change in the amount of deviation with respect to the composition are different from each other, and a function defined for each of the plurality of flow meters, wherein the composition is known. A specific heat difference between a standard gas that is the raw fuel gas and the raw fuel gas supplied to the reformer, a function indicating a relationship between the deviation amount, and the detected values of the plurality of flow meters. Based And calculating the specific heat difference, and a gas type specifying unit for specifying the gas type of the raw fuel gas supplied to the reformer based on the calculated specific heat difference and the specific heat of the standard gas. .

  Such a fuel cell system includes a plurality of flow meters each detecting a flow rate of the raw fuel gas supplied to the reformer, and a gas type specifying unit that specifies the gas type of the raw fuel gas supplied to the reformer. Including. Each flow meter is configured such that the amount of deviation of the detected value with respect to the true value of the flow rate changes in accordance with the composition of the raw fuel gas. The characteristics of the shift amount change are different from each other. Further, for each flow meter, the specific heat difference between the standard gas, which is the raw fuel gas whose composition is known, and the raw fuel gas supplied to the reformer, and the detected value for the true value of the flow rate in the flow meter A function indicating the relationship with the deviation amount is defined. Here, the specific heat of the raw fuel gas has a correlation with the composition of the raw fuel gas (the concentration of the combustible component), and the specific heat difference between the standard gas and the raw fuel gas supplied to the reformer is the raw fuel gas. It changes according to the difference in composition between the gas and the standard gas. Therefore, it is possible to calculate the specific heat difference based on the functions and the detection values of the plurality of flow meters, and the raw fuel gas supplied to the reformer based on the calculated specific heat difference and the specific heat of the standard gas. The gas type can be specified with high accuracy. Then, by reflecting the specified gas type of the raw fuel gas in the control of the fuel cell system, even if the composition of the raw fuel gas is changed, the output of the fuel cell system is reduced due to excess or deficiency of the raw fuel gas. And a reduction in durability can be favorably suppressed.

  The gas type specifying method of the raw fuel gas of the present disclosure is a gas type specifying method of the raw fuel gas that specifies the gas type of the raw fuel gas supplied to the reformer that generates the anode gas of the fuel cell, A plurality of flowmeters in which the amount of deviation of the detected value with respect to the true value of the flow rate is configured to change in accordance with the composition of the raw fuel gas and the characteristics of the change in the amount of deviation with respect to the composition are different from each other, The flow rate of the raw fuel gas supplied to the reformer is detected, and a function defined for each of the plurality of flow meters, the standard gas being the raw fuel gas whose composition is known, and the reforming gas are detected. Calculating the specific heat difference based on the specific heat difference between the raw fuel gas supplied to the fuel cell and the function indicating the relationship between the deviation amount and the detection values of the plurality of flow meters. The specific heat difference and the standard gas The supplied to the reformer on the basis of the specific heat is to identify the gas species of the raw fuel gas.

  According to such a method, even when the composition of the raw fuel gas changes, it is possible to favorably suppress a decrease in output and durability of the fuel cell system due to an excess or deficiency of the raw fuel gas.

1 is a schematic configuration diagram illustrating a fuel cell system according to the present disclosure. 2 is a chart showing characteristics of a plurality of flow meters included in the fuel cell system of FIG. 5 is a flowchart illustrating an example of a routine executed in the fuel cell system according to the present disclosure. FIG. 10 is a schematic configuration diagram illustrating another fuel cell system of the present disclosure. 5 is a table showing characteristics of a plurality of flow meters included in the fuel cell system of FIG.

  Next, an embodiment for carrying out the invention of the present disclosure will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating a fuel cell system 10 of the present disclosure. A fuel cell system 10 shown in FIG. 1 includes a power generation unit 20 having a fuel cell stack FCS that generates power by an electrochemical reaction between hydrogen in anode gas (fuel gas) and oxygen in cathode gas (oxidant gas), and hot and cold water. A hot water supply unit 100 having a hot water storage tank 101 for storing water, and a control device 80 for controlling the entire system. The power generation unit 20 includes a fuel cell stack FCS, a power generation module 30 including a box-shaped module case 31 formed of a heat insulating material, a vaporizer (evaporator) 33, two reformers 34, and the like. A raw fuel gas supply system 40 for supplying a raw fuel gas (raw fuel) such as city gas (natural gas) or LP gas to the vaporizer 33 of the module 30, and a cathode gas to the fuel cell stack FCS of the power generation module 30. And a reforming water supply system 55 for supplying reforming water to the carburetor 33 of the power generation module 30, and a waste heat generated in the power generation module 30. The exhaust heat recovery system 60, the power conditioner 71 connected to the output terminal of the fuel cell stack FCS, and the housing 22 accommodating them. Including.

  In the present embodiment, the power generation module 30 includes two fuel cell stacks FCS, and the two fuel cell stacks FCS are installed on a manifold 32 disposed in a module case 31 so as to face each other at an interval. You. Each fuel cell stack FCS has, for example, an electrolyte such as zirconium oxide, an anode electrode and a cathode electrode sandwiching the electrolyte, and a plurality of solid oxide single cells arranged in the left-right direction (horizontal direction) in FIG. The cell SC is included. An anode gas passage (not shown) is formed in the anode electrode of each single cell SC so as to extend in a direction orthogonal to the arrangement direction of the single cells SC, that is, in a vertical direction. Around the cathode electrode of each single cell SC, a cathode gas passage (not shown) through which a cathode gas flows is formed so as to extend in a direction orthogonal to the arrangement direction of the single cells SC, that is, in a vertical direction. The anode gas passage of each single cell SC is connected to an anode gas passage 320 formed in the manifold 32, and the cathode gas passage of each single cell SC is connected to a cathode gas passage 310 in the module case 31.

  The vaporizer 33 and the reformer 34 of the power generation module 30 are disposed above the two fuel cell stacks FCS in the module case 31 with a space therebetween. In the present embodiment, the vaporizer 33 and one reformer 34 are arranged above one fuel cell stack FCS, and the other reformer 34 is arranged above the other fuel cell stack FCS. Further, between the fuel cell stack FCS and the vaporizer 33 and the one reformer 34, and between the other fuel cell stack FCS and the other reformer 34 in the vertical direction, the fuel cell stack FCS And a combustion section 35 for generating heat necessary for the reaction in the vaporizer 33 and the reformer 34. Each of the combustion units 35 is provided with an ignition heater 36, and at least one of the combustion units 35 is provided with a temperature sensor 37 so as to be close to the fuel cell stack FCS.

  The carburetor 33 heats the raw fuel gas from the raw fuel gas supply system 40 and the reformed water from the reformed water supply system 55 by heat from the combustion unit 35 to preheat the raw fuel gas and to form the reformed water. Is evaporated to produce water vapor. The raw fuel gas preheated by the vaporizer 33 is mixed with steam, and the mixed gas of the preheated raw fuel gas and steam flows from the vaporizer 33 into the reformer 34. The reformer 34 has, for example, a Ru-based or Ni-based reforming catalyst filled therein, and reacts the mixed gas from the vaporizer 33 with the reforming catalyst in the presence of heat from the combustion unit 35. (Steam reforming reaction) generates hydrogen gas and carbon monoxide. Further, the reformer 34 generates hydrogen gas and carbon dioxide by a reaction between carbon monoxide generated by the steam reforming reaction and steam (carbon monoxide shift reaction). As a result, the reformer 34 generates an anode gas including hydrogen, carbon monoxide, carbon dioxide, water vapor, unreformed raw fuel gas, and the like. The anode gas generated by the reformer 34 is supplied to the anode electrode of each single cell SC via a piping (not shown) or an anode gas passage 320 of the manifold 32.

In addition, air as a cathode gas containing oxygen is supplied to the cathode electrode of each single cell SC of the fuel cell stack FCS via the cathode gas passage 310 in the module case 31. Oxide ions (O ₂ ⁻ ) are generated at the cathode electrode of each single cell SC, and the oxide ions permeate the electrolyte and react with hydrogen and carbon monoxide at the anode electrode, thereby obtaining electric energy. The anode gas (hereinafter, referred to as “anode off gas”) and the cathode gas (hereinafter, referred to as “cathode off gas”) not used for the electrochemical reaction (power generation) in each single cell SC are supplied to the anode gas passage of each single cell SC, It flows out from the cathode gas passage to the upper combustion section 35.

  The anode offgas flowing into the combustion unit 35 from each single cell SC is a combustible gas containing a fuel component such as hydrogen or carbon monoxide, and is mixed with the cathode offgas containing oxygen flowing into the combustion unit 35 from each single cell SC. Fit. Hereinafter, a mixed gas of the anode off gas and the cathode off gas is referred to as “off gas”. When the off gas (anode off gas) is ignited in the combustion section 35 by being ignited by the ignition heater 36, the combustion of the off gas causes the operation of the fuel cell stack FCS, the preheating of the raw fuel gas in the carburetor 33 and the generation of water vapor. The heat required for the generation and the steam reforming reaction in the reformer 34 is generated. Further, with the combustion of the off-gas, in the combustion section 35, combustion exhaust gas containing water vapor is generated.

  As shown in FIG. 1, a raw fuel gas supply system 40 includes a raw fuel gas supply pipe 41 that connects a raw fuel supply source 1 that supplies city gas or LP gas to a carburetor 33, and a raw fuel gas supply pipe 41. The raw fuel gas supply valve (electromagnetic opening / closing valve) 42 and the raw fuel gas pump 44 which are incorporated in the raw fuel gas supply pipe 41 so as to be located between the carburetor 33 and the raw fuel gas pump 44 A desulfurization type desulfurizer 45. Further, a pressure sensor 46 and first and second flow meters 47 and 48 are incorporated between the raw fuel gas supply valve 42 and the raw fuel gas pump 44 of the raw fuel gas supply pipe 41. The pressure sensor 46 is incorporated in the raw fuel gas supply pipe 41 so as to be located near the discharge port of the raw fuel gas pump 44, and detects the pressure of the raw fuel gas flowing through the raw fuel gas supply pipe 41. The first and second flow meters 47 and 48 are thermal flow meters that include a temperature sensor and a heater (not shown). The first and second flow meters 47 and 48 are based on a change in the temperature of the raw fuel gas to which heat is applied from the heater. , The flow rate of the raw fuel gas flowing through the raw fuel gas supply pipe 41 toward the reformer 34 (vaporizer 33) per unit time is detected.

  The cathode gas supply system 50 includes a cathode gas supply pipe 51 connected to a cathode gas passage 310 in the module case 31, an air filter 52 installed at a gas inlet of the cathode gas supply pipe 51, and a cathode gas supply pipe 51. And an integrated blower 53. By operating the blower 53, the air as the cathode gas sucked in through the air filter 52 is pressure-fed (supplied) to each fuel cell stack FCS through the cathode gas passage 310 by the blower 53. The cathode gas supply pipe 51 is provided with a flow rate switch 54 that is turned on when the flow rate of the cathode gas flowing through the cathode gas supply pipe 51 per unit time reaches a predetermined value.

  The reforming water supply system 55 includes a reforming water supply pipe 56 connected to the vaporizer 33, a reforming water tank 57 connected to the reforming water supply pipe 56 and storing the reforming water, And a reforming water pump 58 incorporated in the supply pipe 56. By operating the reforming water pump 58, the reforming water in the reforming water tank 57 is pumped (supplied) to the vaporizer 33 by the reforming water pump 58. Further, a water purifier (not shown) for purifying the stored reformed water is provided in the reformed water tank 57.

  The exhaust heat recovery system 60 includes a circulation pipe 61 connected to the hot water storage tank 101 of the hot water supply unit 100, and a heat exchanger that exchanges heat between hot water flowing through the circulation pipe 61 and combustion exhaust gas from the combustion unit 35 of the power generation module 30. 62 and a circulation pump 63 incorporated in the circulation pipe 61. By operating the circulation pump 63, the hot and cold water stored in the hot water storage tank 101 is introduced into the heat exchanger 62 by the circulation pump 63, and the hot and cold water, which has taken heat from the combustion exhaust gas and raised in temperature, by the heat exchanger 62. It can be returned to the hot water storage tank 101.

  Further, the exhaust heat recovery system 60 consumes power from the radiator 64 incorporated in the circulation pipe 61, a radiator fan (electric fan) 65 for sending air to the radiator 64, and power from the power generation module 30, and An electric heater (for example, a ceramic heater) 66 for heating hot water and a thermistor (temperature sensor) 67 for detecting the temperature of hot water heated by the electric heater 66 are included. The radiator 64 is incorporated in the circulation pipe 61 so as to be located between the heat exchanger 62 and the circulation pump 63, and the electric heater 66 is connected to the circulation pipe 61 so as to be located between the circulation pump 63 and the radiator 64. Be incorporated. Further, the thermistor 67 is installed on the downstream side of the electric heater 66 so as to be close to the electric heater 66.

  When the output required for the power generation module 30 (fuel cell stack FCS) is lower than the normal rated output, the electric heater 66 is operated to consume the surplus power. Further, at this time, the duty of the circulation pump 63 is controlled so that the water temperature detected by the thermistor 67 becomes a predetermined temperature, and the radiator fan 65 is operated as necessary. Thus, even when the output required of the power generation module 30 is low, the heat exchanger 62 can recover the exhaust heat of each fuel cell stack FCS, or can cause the electric heater 66 to consume the surplus power of the power generation module. Meanwhile, the operation of the power generation module 30 can be continued. In addition, by appropriately operating the radiator fan 65 to feed air into the radiator 64, the hot water flowing through the circulation pipe 61 is cooled (dissipated), and the temperature of the hot water in the hot water storage tank 101 is prevented from rising more than necessary. can do.

  Further, a heat exchanger 62 (a passage of the combustion exhaust gas) of the exhaust heat recovery system 60 is connected to a reforming water tank 57 via a pipe. The condensed water obtained by condensing by exchange is introduced into the reformed water tank 57 through the pipe. Further, a passage of the combustion exhaust gas of the heat exchanger 62 is connected to an exhaust pipe 68. Thus, the exhaust gas discharged from the combustion section 35 of the power generation module 30 and from which the moisture has been removed by the heat exchanger 62 is discharged to the atmosphere via the exhaust pipe 68.

  The power conditioner 71 includes a DC / DC converter that boosts the DC power from each fuel cell stack FCS, an inverter that converts the DC power from the DC / DC converter into AC power, and the like (all not shown). An output terminal of the power conditioner 71 (inverter) is connected to a power line 3 connected to the system power supply 2. This makes it possible to convert DC power from each fuel cell stack FCS into AC power and supply it to the load 4 such as a home electric appliance. Further, the fuel cell system 10 includes a power supply board 72 connected to the power conditioner 71. The power supply board 72 converts DC power from each fuel cell stack FCS or AC power from the system power supply 2 into low-voltage DC power, and supplies the raw fuel gas supply valve 42, the raw fuel gas pump 44, the blower 53, the reforming water pump The DC power is supplied to accessories such as the pump 58, the circulation pump 63 and the radiator fan 65, sensors such as the temperature sensor 37, and the controller 80.

  In addition, a cooling fan (not shown) for cooling the power conditioner 71, the power supply board 72, and the like, and the ventilation fan 24 are arranged in the auxiliary equipment room in which the power conditioner 71, the power supply board 72, and the like are arranged. Have been. A cooling fan (not shown) sends air to the heat generating portion of the power conditioner 71 and the power supply board 72, and the air that has cooled and heated the heat generating portion is discharged to the atmosphere by the ventilation fan 24.

  The control device 80 is a computer including a CPU 81, a ROM 82 for storing various programs, a RAM 83 for temporarily storing data, an input port, an output port, and the like (all not shown). The control device 80 inputs detection values of the temperature sensor 37, the pressure sensor 46, the first and second flow meters 47 and 48, the thermistor 67, and the like, a signal from the flow switch 54, and the like via an input port. The control device 80 includes the ventilation fan 24, the ignition heater 36, the solenoid of the raw fuel gas supply valve 42, the raw fuel gas pump 44, the blower 53, the reforming water pump 58, the circulation pump 63, the radiator fan 65, and the electric heater 66. A control signal to a power conditioner 71 (DC / DC converter and inverter), a power supply board 72, a display unit (not shown), and the like is output through an output port to control these devices. Further, a remote controller (not shown) is connected to the control device 80 via a wireless or wired communication line. The control device 80 executes various controls based on signals from the remote controller operated by the user of the fuel cell system 10.

  FIG. 2 is a table showing characteristics of the first and second flow meters 47 and 48 included in the fuel cell system 10. As shown in the figure, the first and second flow meters 47 and 48 are configured such that the deviation d of the detected value with respect to the true value of the flow rate is different from that of the standard gas (for example, a 13A city gas) whose composition is known. It is configured to change substantially in proportion to the specific heat difference ΔC with the raw fuel gas flowing through the fuel gas supply pipe 41. Further, as shown in the drawing, the first flow meter 47 and the second flow meter 48 have different characteristics in the change of the deviation amount d with respect to the specific heat difference ΔC.

In the present embodiment, the relationship between the specific heat difference ΔC in the first flow meter 47 and the deviation d is expressed by a first function f ₁ (ΔC) shown in the following equation (1). The relationship between ΔC and the deviation amount d is represented by a second function f ₂ (ΔC) shown in the following equation (2). However, “a ₁ ” and “b ₁ ” in the equation (1) and “a ₂ ” and “b ₂ ” in the equation (2) are predetermined constants, and the constants a ₁ and a ₂ are , A ₁ ≠ a ₂ ≠ 0. Further, the constants b ₁ and b ₂ may be zero or a real number other than zero. In the present embodiment, b ₁ ≠ b ₂ , but even if b ₁ = b ₂ Good.

d = f ₁ (ΔC) = a ₁ ΔC + b ₁ (1)
d = f ₂ (ΔC) = a ₂ ΔC + b ₂ (2)

Here, the specific heat of the raw fuel gas such as city gas or LP gas has a correlation with the composition of the raw fuel gas (the concentration of combustible components such as methane, ethane, propane, and butane). The specific heat difference ΔC between the raw fuel gas flowing through 41 and the raw fuel gas changes depending on the composition difference between the raw fuel gas and the standard gas. Therefore, the first and second flow meters 47 and 48 have a characteristic that the deviation amounts d1 and d2 of the detected values with respect to the true value of the flow rate change according to the composition of the raw fuel gas flowing through the raw fuel gas supply pipe 41. . Then, the first and second flow meters 47 and 48 basically determine the flow rate of the raw fuel gas having a certain composition (except when the specific heat difference ΔC is a value corresponding to the intersection of the first and second functions). A different value is output, and the difference ΔF between the detection values of the first and second flow meters 47 and 48 is, as shown in FIG. 2, the deviation amount of the first flow meter 47 determined from the first function f ₁ (ΔC). This corresponds to the difference (= d2−d1) between d1 and the deviation amount d2 of the second flowmeter 48 determined from the second function f ₂ (ΔC).

  Next, a procedure for measuring the flow rate of the raw fuel gas and a control procedure for the raw fuel gas pump 44 in the above-described fuel cell system 10 will be described.

  FIG. 3 shows the raw fuel gas when the fuel cell system 10 is started (for example, when a fuel adsorption process for adsorbing a fuel component to the desulfurizer 45 to suppress the air-fuel ratio deviation of the mixed gas is performed) or during operation. 5 is a flowchart showing an example of a routine repeatedly executed at predetermined time intervals by a control device 80 to control the raw fuel gas pump 44 while measuring the flow rate of the raw fuel gas. At the start of the routine of FIG. 3, the CPU 81 of the control device 80 first acquires the detection value F1 of the first flow meter 47 and the detection value F2 of the second flow meter 48 (step S100), and detects the detection value F1. The difference ΔF from the value F2 (= F2−F1) is calculated (step S110).

Next, the CPU 81 determines the first and second functions f ₁ (ΔC) and f ₂ (ΔC) defined for the first and second flow meters 47 and 48, and the difference ΔF between the detected value F1 and the detected value F2. , The specific heat difference ΔCx between the standard gas and the raw fuel gas flowing through the raw fuel gas supply pipe 41 toward the reformer 34 at that time is calculated (step S120). As described above, the difference ΔF between the detection values F1 and F2 of the first and second flow meters 47 and 48 is determined by the deviation d1 of the first flow meter 47 determined from the first function f ₁ (ΔC) and the second function Since it matches the difference (= d2−d1) from the deviation amount d2 of the second flow meter 48 determined from f ₂ (ΔC), the following expression (3) is established. Therefore, in step S120, the CPU 81 calculates the specific heat difference ΔCx from the following equation (4) obtained by modifying equation (3).

ΔF = a ₂ ΔCx + b ₂ − (a ₁ ΔCx + b ₁ ) (3)
ΔCx = (ΔF + b ₁ −b ₂ ) / (a ₂ −a ₁ ) (4)

After calculating the specific heat difference ΔCx in step S120, the CPU 81 sets the deviation d1 of the detection value F1 of the first flow meter 47 with respect to the true value of the flow rate of the raw fuel gas flowing through the raw fuel gas supply pipe 41 to the first value. Based on the function f ₁ (ΔC) and the specific heat difference ΔCx, it is calculated as d1 = a ₁ · ΔCx + b ₁ (step S130). Further, the CPU 81 subtracts the deviation d1 calculated in step S130 from the detection value F1 of the first flow meter 47 obtained in step S100, and calculates the true value of the flow rate of the raw fuel gas flowing through the raw fuel gas supply pipe 41. Ft (= F1-d1) is calculated (step S140).

In step S130 of FIG. 3, instead of the displacement d1 of the first flow meter 47, the displacement d2 of the second flow meter 48 is calculated based on the second function f ₂ (ΔC) and the specific heat difference ΔCx. It may be calculated as d2 = a ₂ · ΔCx + b _{2. In} this case, in step S140, the true value Ft of the flow rate of the raw fuel gas may be calculated as Ft = F2-d2. Further, in step S130 of FIG. 3, both the displacement d1 of the first flow meter 47 and the displacement d2 of the second flow meter 48 may be calculated. In this case, in step S140, the first flow meter 47 may be calculated. Of the raw fuel gas calculated from the first function f ₁ (ΔC) and the deviation d1 and the raw fuel gas calculated from the second function f ₂ (ΔC) of the second flow meter 48 and the deviation d2. (= (F1-d1 + F2-d2) / 2) may be calculated as the true value Ft of the flow rate.

Subsequently, CPU 81 is the specific heat Cx of the raw fuel gas by adding the specific heat difference ΔCx calculated at step S120 to the specific heat C ₀ of the standard gas obtained in advance flowing raw fuel gas supply pipe 41 (= C ₀ + ΔCx) (step S150), and the gas type of the raw fuel gas flowing through the raw fuel gas supply pipe 41 is calculated based on the calculated specific heat ratio Cx and a gas type table (not shown) created in advance and stored in the ROM 82. Is specified (step S160). The gas type table associates the gas type of the raw fuel gas with the specific heat ratio, and in step S160, the CPU 81 specifies the gas type corresponding to the specific heat ratio ΔCx from the gas type table.

  Further, the CPU 81 determines whether or not the gas type has changed by comparing the gas type specified in step S160 with the control gas type set at that time (step S170). If it is determined that it has changed (step S170: YES), the gas type corresponding to the specific heat ratio ΔCx is set as the control gas type (step S180). If a negative determination is made in step S170, the CPU 81 skips the processing in step S180. Further, the gas type table may be a table in which a gas company or a region is associated with specific heat in addition to the gas type.

  After the processing in step S170 or S180, the CPU 81 sets a target flow rate of the raw fuel gas supplied from the raw fuel gas supply system 40 to the reformer 34 (vaporizer 33) (step S190). In step S190, the CPU 81 calculates the calorific value according to the target current value of the fuel cell FCS set separately and the specific heat (gas type, ie, composition of the raw fuel gas) predetermined for the control gas type. Then, the target flow rate of the raw fuel gas according to the calorie is calculated.

  Further, the CPU 81 calculates the detected values of the first and second flow meters 47 and 48 from the true value Ft of the flow rate calculated in step S140, the target flow rate set in step S190, and the relational expression of the feedback control. The target duty ratio of the raw fuel gas pump 44 is set so that the true value Ft of the flow rate calculated in step S140 on the basis of the target flow rate matches the target flow rate set in step S190 (step S200). Then, the CPU 81 controls (feedback control) the raw fuel gas pump 44 based on the target duty ratio set in step S200 (step S210), terminates this routine once, and at the time when the next execution timing comes. Then, the routine of FIG. 3 is executed again.

As a result of the execution of the routine of FIG. 3 as described above, in the fuel cell system 10, the raw fuel gas flowing through the raw fuel gas supply pipe 41 from the raw fuel supply source 1 to the reformer 34 (vaporizer 33) Is accurately calculated. That is, the first and second flow meters 47 and 48 of the fuel cell system 10 determine that the deviation d of the detected value with respect to the true value of the flow rate has a specific heat having a correlation with the composition of the raw fuel gas flowing through the raw fuel gas supply pipe 41. The first and second flow meters 47 and 48 have specific heat differences ΔC between the standard gas and the raw fuel gas supplied to the reformer 34, and the deviation d. The first and second functions f ₁ (ΔC) and f ₂ (ΔC) indicating the relationship are defined. Further, the first and second flow meters 47 and 48 output basically different values as the flow rate of the raw fuel gas having a certain composition. Further, the difference ΔF between the detection values of the first and second flow meters 47 and 48 is obtained from the deviation d1 of the first flow meter 47 determined from the first function f ₁ (ΔC) and the second function f ₂ (ΔC). The difference is equal to the determined difference d2 of the second flow meter 48.

Accordingly, the detection values F1 and F2 of the first and second flow meters 47 and 48 (the difference ΔF between them), the first function f ₁ (ΔC) indicating the characteristics of the first flow meter 47, and the second flow meter 48 It is possible to calculate at least one of the deviation amounts d1 and d2 of the detection values F1 and F2 of the first and second flow meters 47 and 48 from the second function f ₂ (ΔC) indicating the characteristic of (Steps S110-S130). More specifically, the difference ΔF between the detection values F1 and F2 of the first and second flow meters 47 and 48 and the deviation d1 obtained from the first and second functions f ₁ (ΔC) and f ₂ (ΔC). , D2 to calculate the specific heat difference ΔCx from the difference between the specific heat difference ΔCx and at least one of the first and second functions f ₁ (ΔC) and f ₂ (ΔC). Can be accurately calculated. The raw fuel gas supplied to the reformer 34 from at least one set of the detection value F1 and the displacement d1 of the first flowmeter 47 and the detection value F2 and the displacement d2 of the second flowmeter 48. Can be accurately calculated (step S140).

  Thus, in the fuel cell system 10, even when the composition of the raw fuel gas changes, the flow rate of the raw fuel gas supplied to the reformer 34 is accurately acquired by the control device 80 as an arithmetic processing unit. This makes it possible to accurately supply the anode gas as required from the reformer 34 to each fuel cell stack FCS. As a result, even if the composition of the raw fuel gas changes, it is possible to favorably suppress a decrease in the output and durability of the fuel cell system 10 due to an excess or deficiency of the raw fuel gas.

Further, the control device 80 as the gas type specifying unit specifies the gas type of the raw fuel gas supplied to the reformer 34 based on the calculated specific heat difference ΔCx and the specific heat C _{0 of the} standard gas (Step S160). . That is, the specific heat of the raw fuel gas has a correlation with the composition of the raw fuel gas (the concentration of the combustible component), and can be obtained from the specific heat difference ΔCx and the specific heat C _{0 of the} standard gas. Accordingly, by calculating the specific heat difference ΔCx, the gas type of the raw fuel gas can be accurately specified from the specific heat difference ΔCx and the specific heat C _{0 of the} standard gas. Then, by setting the specified gas type of the raw fuel gas as the control gas type and reflecting the same in the control of the fuel cell system (steps S170 and S180), the performance and durability of each fuel cell stack FCS are improved. , And the accuracy of information such as the amount of heat and the amount of CO ₂ reduction displayed on the display unit of the fuel cell system 10 or the remote controller can be further improved.

  Further, the control device 80 as a pump control unit sets the target flow rate of the raw fuel gas from the heat amount corresponding to the target current value of the fuel cell stack FCS and the gas type (specific heat, that is, composition) of the raw fuel gas, and sets the first target flow rate. And the raw fuel gas pump 44 is controlled such that the flow rate of the raw fuel gas calculated based on the detection values of the second flow meters 47 and 48 matches the target flow rate (steps S190 to S210). As a result, the flow rate of the raw fuel gas is accurately calculated, and the target flow rate of the raw fuel gas is set more appropriately according to the gas type (composition) of the raw fuel gas supplied to the reformer 34. Therefore, it is possible to more accurately supply the anode gas as required from the reformer 34 to each fuel cell FCS.

In the above embodiment, the first and second functions f ₁ (ΔC) and f ₂ (ΔC) of the first and second flow meters 47 and 48 are both linear functions, but are not limited thereto. Absent. That is, at least one of the first and second functions f ₁ (ΔC) and f ₂ (ΔC) is different from the specific heat difference ΔC (composition) between the standard gas and the raw fuel gas supplied to the reformer 34. Any function other than the linear function, for example, a function of a quadratic or higher order, may be used as long as it shows a relationship with the quantity d.

  FIG. 4 is a schematic configuration diagram illustrating another fuel cell system 10B of the present disclosure. Note that among the constituent elements of the fuel cell system 10B, the same elements as those of the above-described fuel cell system 10 are denoted by the same reference numerals, and redundant description will be omitted.

The fuel cell system 10B shown in FIG. 4 incorporates a third flow meter 49 in addition to the first and second flow meters 47 and 48 in the raw fuel gas supply pipe 41 of the fuel cell system 10 described above. Is equivalent to Also in the third flow meter 49, the deviation amount d of the detected value with respect to the true value of the flow rate is substantially proportional to the specific heat difference ΔC between the standard gas whose composition is known and the raw fuel gas flowing through the raw fuel gas supply pipe 41. It is configured to change. Further, among the first, second, and third flow meters 47, 48, and 49 of the fuel cell system 10B, as shown in FIG. 5, the characteristics of the change in the deviation d with respect to the specific heat difference ΔC are different from each other. Further, the relationship between the specific heat difference ΔC and the amount of deviation d in the third flow meter 49 is expressed by a third function f ₃ (ΔC) shown in the following equation (5). However, “a ₃ ” and “b ₃ ” in the equation (5) are both predetermined constants, and the constant a ₃ satisfies a ₃ ≠ a ₁ ≠ a ₂ ≠ 0. Also, the constant b ₃ may be zero, or may be a real number other than zero. Further, in the example shown in FIG. 5, b ₁ ≠ b ₂ ≠ b ₃ , but any two or all of the constants b ₁ , b ₂ and b ₃ may be the same.

d = f ₃ (ΔC) = a ₃ · ΔC + b ₃ (5)

In the fuel cell system 10B including such three flow meters 47, 48, and 49, as shown in FIG. 5, the difference ΔF ₁₂ between the detection values F1 and F2 of the first and second flow meters 47 and 48 is The displacement d1 of the first flow meter 47 determined from the first function f ₁ (ΔC) of the first flow meter 47 and the second flow meter 48 determined from the second function f ₂ (ΔC ＾) of the second flow meter 48. And the difference from the deviation amount d2. Further, the difference ΔF ₁₃ between the detection values F 1 and F 3 of the first and third flow meters 47 and 49 is determined by the first function f ₁ (ΔC) of the first flow meter 47, and the deviation amount of the first flow meter 47 is determined. This is equal to the difference between d1 and the displacement d3 of the third flow meter 49 determined from the third function f ₃ (ΔC) of the third flow meter 49. Further, the difference ΔF ₂₃ between the detection values F 2 and F 3 of the second and third flow meters 48 and 49 is determined by the second function f ₂ (ΔC) of the second flow meter 48, and the deviation amount of the second flow meter 48 is determined. This is equal to the difference between d2 and the displacement d3 of the third flow meter 49 determined from the third function f ₃ (ΔC) of the third flow meter 49.

Therefore, in the fuel cell system 10B, from the relationship of ΔF ₁₂ = F2-F1 = d2-d1, ΔF ₁₃ = F1-F3 = d1-d3, and ΔF ₂₃ = F2-F3 = d2-d3, the standard gas and the reforming gas are used. After obtaining three values as the specific heat difference ΔCx with the raw fuel gas supplied to the heater 34, the average value of the three values is used as the value of the specific heat difference ΔCx to obtain the first, second, and third values. The specific heat difference ΔCx can be calculated more accurately while reducing the influence of detection errors of the three flow meters 47, 48, and 49. Further, in the fuel cell system 10B, and the detected value F1, F2 difference [Delta] F ₁₂ between, based on the maximum value of the detection values F1, F3 difference [Delta] F ₁₃ between, and the detected value F2, F3 difference [Delta] F ₂₃ between the The specific heat difference ΔCx may be calculated in this manner, and even if the specific heat difference ΔCx is calculated in this manner, the influence of detection errors of the first, second, and third flow meters 47, 48, and 49 can be reduced.

As a result, the specific heat difference ΔCx calculated accurately, at least one of the first, second, and third functions f ₁ (ΔC), f ₂ (ΔC), f ₃ (ΔC), and the detection value F1, From either one of F2 and F2, the true value Ft of the flow rate of the raw fuel gas supplied to the reformer 34 can be calculated more accurately. Also, in the fuel cell system 10B, the first, second and third functions are determined from the specific heat difference ΔCx and the first, second and third functions f ₁ (ΔC), f ₂ (ΔC) and f ₃ (ΔC). All of the deviation amounts d1, d2, and d3 of the flow meters 47, 48, and 49 are calculated, and the flow rate value of the raw fuel gas calculated from the first function f ₁ (ΔC) of the first flow meter 47 and the deviation amount d1. And the flow rate value of the raw fuel gas calculated from the second function f ₂ (ΔC) of the second flow meter 48 and the deviation amount d2, and the third function f ₃ (ΔC) and the deviation amount d3 of the third flow meter 49. Can be calculated as the true value Ft of the flow rate.

As a result, in the fuel cell system 10B, the accuracy of calculation of the flow rate of the raw fuel gas by the control device 80 is further improved while reducing the influence of the detection errors of the first, second, and third flow meters 47, 48, 49. Becomes possible. In addition, since the calculation accuracy of the specific heat difference ΔCx is improved, the accuracy of specifying the gas type by the control device 80 can be improved. From these points, it will be understood that the raw fuel gas supply pipe 41 may incorporate four or more flow meters. Further, also in the fuel cell system 10B, the first, second and third functions f ₁ (ΔC) and f ₂ (ΔC) of the first, second and third flow meters 47, 48 and 49 are f ₃ (ΔC), both are linear functions, but are not limited thereto. That is, at least one of the first, second, and third functions f ₁ (ΔC), f ₂ (ΔC), and f ₃ (ΔC) corresponds to the standard gas and the source supplied to the reformer 34. Any function other than a linear function, for example, a function of a quadratic or higher order, may be used as long as it shows the relationship between the specific heat difference ΔC (composition) with the fuel gas and the deviation amount d.

As described above, the fuel cell system 10 of the present disclosure includes a fuel cell stack FCS including a plurality of single cells SC that generate electric power by an electrochemical reaction between an anode gas and a cathode gas, and a fuel cell stack FCS that reforms a raw fuel gas to form an anode. A reformer 34 for generating gas, first and second flow meters 47 and 48 for detecting a flow rate of the raw fuel gas supplied to the reformer 34, and control as an arithmetic processing unit and a gas type specifying unit. Device 80. Further, the first and second flow meters 47 and 48 are configured such that the deviation amounts d1 and d2 of the detection values F1 and F2 with respect to the true value of the flow rate change in accordance with the composition of the raw fuel gas, that is, the specific heat difference ΔC. In addition, the characteristics of changes in the deviation amounts d1 and d2 of the first and second flow meters 47 and 48 with respect to the composition of the raw fuel gas are different from each other. Further, the control device 80 as an arithmetic processing unit converts the first and second functions f ₁ (ΔC) and f ₂ (ΔC) indicating the characteristics of the first and second flow meters 47 and 48 and the detected values F1 and F2 into Based on this, at least one of the deviation amounts d1 and d2 of the detection values F1 and F2 of the first and second flow meters 47 and 48 is calculated (Steps S110 to S130), and the detection values F1 and F1 of the first flow meter 47 are calculated. The flow rate of the raw fuel gas supplied to the reformer 34 is calculated from at least one set of the shift amount d1 and the detected value F2 of the second flow meter 48 and the shift amount d2 (step S140). Further, the control device 80 as the gas type specifying unit calculates the specific heat difference ΔCx calculated based on the first and second functions f ₁ (ΔC) and f ₂ (ΔC) and the detected values F1 and F2 and the specific heat C of the standard gas. Based on ₀ , the gas type of the raw fuel gas supplied to the reformer 34 is specified (steps S160-S180). As a result, even when the composition of the raw fuel gas changes, it is possible to favorably suppress a decrease in the output and durability of the fuel cell system 10 due to excess or deficiency of the raw fuel gas.

  It should be noted that the invention of the present disclosure is not limited to the above embodiment at all, and it goes without saying that various changes can be made within the scope of the present disclosure. Further, the above-described embodiment is merely a specific embodiment of the invention described in the summary of the invention, and does not limit the elements of the invention described in the summary of the invention.

  The invention of the present disclosure can be used in the fuel cell system manufacturing industry and the like.

  1 Raw fuel supply source, 2 system power supply, 3 power line, 4 load, 10 and 10B fuel cell system, 20 power generation unit, 22 housing, 24 ventilation fan, 30 power generation module, 31 module case, 32 manifold, 33 carburetor , 34 reformer, 35 combustion section, 36 ignition heater, 37 temperature sensor, 40 raw fuel gas supply system, 41 raw fuel gas supply pipe, 42 raw fuel gas supply valve, 44 raw fuel gas pump, 45 desulfurizer, 46 pressure Sensor, 47 first flow meter, 48 second flow meter, 49 third flow meter, 50 cathode gas supply system, 51 cathode gas supply pipe, 52 air filter, 53 blower, 54 flow switch, 55 reformed water supply system, 56 reforming water supply pipe, 57 reforming water tank, 58 reforming water pump, 60 exhaust heat recovery system, 61 circulation distribution , 62 heat exchanger, 63 circulation pump, 64 radiator, 65 radiator fan, 66 electric heater, 67 thermistor, 68 exhaust pipe, 71 power conditioner, 72 power supply board, 80 control device, 81 CPU, 82 ROM, 83 RAM, 310 cathode gas passage, 320 anode gas passage, FCS fuel cell stack, SC single cell.

Claims (8)

In a fuel cell system including a fuel cell that generates power by an electrochemical reaction between an anode gas and a cathode gas, and a reformer that reforms a raw fuel gas to generate the anode gas,
A plurality of flow meters each detecting a flow rate of the raw fuel gas supplied to the reformer, wherein a deviation amount of a detected value from a true value of the flow rate changes according to a composition of the raw fuel gas. A plurality of flowmeters configured as described above and having different characteristics of the change in the deviation amount with respect to the composition,
Calculating the shift amount of at least one of the flow meters based on the characteristics and the detection values of the plurality of flow meters, and calculating the calculated shift amount and the detection of the at least one flow meter; A processing unit for calculating a flow rate of the raw fuel gas supplied to the reformer from the value and
A fuel cell system comprising: The fuel cell system according to claim 1,
For each of the plurality of flow meters, the relationship between the specific heat difference between the standard gas that is the raw fuel gas whose composition is known and the raw fuel gas supplied to the reformer, and the deviation amount Is defined,
The arithmetic processing unit calculates the specific heat difference based on the functions and the detected values of the plurality of flow meters, and calculates the specific heat difference and the function of the at least one of the flow meters based on the calculated specific heat difference. A fuel cell system that calculates the amount of deviation. The fuel cell system according to claim 2,
The fuel cell system, wherein the arithmetic processing unit calculates the specific heat difference from a difference between the detection values of the plurality of flow meters and a difference between the deviation amounts obtained from the function. The fuel cell system according to claim 2 or 3,
The fuel cell system, wherein the arithmetic processing unit specifies a gas type of the raw fuel gas supplied to the reformer based on the specific heat difference and the specific heat of the standard gas. The fuel processing system according to claim 4,
A raw fuel gas pump for supplying the raw fuel gas to the reformer,
A pump control unit for controlling the raw fuel gas pump,
The pump control unit sets a target flow rate of the raw fuel gas from a calorific value according to a target current value of the fuel cell and the gas type of the raw fuel gas, and calculates the target flow rate calculated by the arithmetic processing unit. A fuel cell system that controls the raw fuel gas pump so that the flow rate of the fuel gas matches the target flow rate. A method of measuring a flow rate of a raw fuel gas supplied to a reformer that generates an anode gas of a fuel cell, the flow rate of the raw fuel gas being measured,
A plurality of flow meters each configured such that the deviation amount of the detected value with respect to the true value of the flow rate changes in accordance with the composition of the raw fuel gas, and the characteristics of the change amount of the deviation amount with respect to the composition are different from each other. Detecting the flow rate of the raw fuel gas supplied to the reformer,
Calculating the shift amount of at least one of the flow meters based on the characteristics and the detection values of the plurality of flow meters, and calculating the calculated shift amount and the detection value of the at least one flow meter; Calculating the flow rate of the raw fuel gas supplied to the reformer from
A method for measuring the flow rate of raw fuel gas. In a fuel cell system including a fuel cell that generates power by an electrochemical reaction between an anode gas and a cathode gas, and a reformer that reforms a raw fuel gas to generate the anode gas,
A plurality of flow meters each detecting a flow rate of the raw fuel gas supplied to the reformer, wherein a deviation amount of a detected value from a true value of the flow rate changes according to a composition of the raw fuel gas. A plurality of flowmeters configured as described above and having different characteristics of the change in the deviation amount with respect to the composition,
A function defined for each of the plurality of flow meters, a specific heat difference between a standard gas that is the raw fuel gas whose composition is known and the raw fuel gas supplied to the reformer, Calculating the specific heat difference based on the function indicating the relationship with the deviation amount and the detected values of the plurality of flow meters, and the reformer based on the calculated specific heat difference and the specific heat of the standard gas. A gas type identification unit that identifies the gas type of the raw fuel gas supplied to the
A fuel cell system comprising: A gas type specifying method of a raw fuel gas that specifies a gas type of a raw fuel gas supplied to a reformer that generates an anode gas of a fuel cell,
A plurality of flow meters each configured such that the deviation amount of the detected value with respect to the true value of the flow rate changes in accordance with the composition of the raw fuel gas and the characteristics of the variation in the deviation amount with respect to the composition are different from each other, Detecting the flow rate of the raw fuel gas supplied to the reformer,
A function defined for each of the plurality of flow meters, a specific heat difference between a standard gas that is the raw fuel gas whose composition is known and the raw fuel gas supplied to the reformer, Calculating the specific heat difference based on the function indicating the relationship with the deviation amount and the detected values of the plurality of flow meters, and the reformer based on the calculated specific heat difference and the specific heat of the standard gas. Identifying a gas type of the raw fuel gas supplied to the
A method for identifying the type of raw fuel gas.

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