JP2006273619A - Reformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reformer which determines a supply of reforming water charged into a reforming section using a steam-carbon ratio control indication value derived on the basis of a supply of fuel for reforming charged into the reforming section, and which supplies reforming water so as to obtain the determined result. <P>SOLUTION: The controller 30 of the reformer comprises: a steam-carbon ratio (S/C) control indication value deriving section 31 which derives an S/C control indication value; an objective reforming water supply deriving section 32 which derives the objective supply of reforming water supplied to the reforming section on the basis of the S/C control indication value derived by the S/C control indication value deriving section 31 and the supply of fuel for reforming detected by a flowmeter for fuel for reforming; and a reforming water supply control section 33 which controls a water pump so as to obtain the objective supply of reforming water derived by the objective reforming water supply deriving section 32. The S/C control indication value deriving section 31 derives the S/C control indication value on the basis of the supply of fuel for reforming detected by the flowmeter for fuel for reforming. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention supplies a reforming fuel and reforming water, and reforms the supplied reforming fuel with a reforming catalyst filled therein, thereby generating a reformed gas containing hydrogen to generate fuel. The present invention relates to a reformer that supplies a battery.

Conventionally, as an example of this type of reformer, one shown in Patent Document 1 “Fuel treatment device, fuel cell power generation system” is known. As shown in Patent Document 1, the fuel processing apparatus includes a reforming unit 11 that reforms a hydrocarbon-based raw material (40, 40a) into a reformed gas 44 mainly composed of hydrogen and carbon monoxide. , A process water supply system 3 that supplies the reforming process water 41 to the reforming unit 11, and a reforming catalyst unit 14 that modifies the reformed gas 44 to reduce the carbon monoxide content in the reformed gas 44; In addition, the temperature of the shift unit 12 having the first heat exchange unit 13 that exchanges heat between the reforming process water 41 and the shift catalyst unit 14 and the shift catalyst unit 14 (or the selective oxidation catalyst unit 19) are detected. Based on the temperature detected by the temperature detector 17 (or the temperature detector 20), a process water amount adjusting device 5 that adjusts the supply amount of the reforming process water 41 is provided, and the process water amount adjusting device 5 is a hydrocarbon-based raw material. Flow rate and preset S / C range It is adapted to increase or decrease the supply amount of the reforming process water 41 within the flow rate range to be al calculated. Accordingly, a fuel processing apparatus having a simple carbon monoxide removal capability even when the load of the fuel cell power generation system is changed is provided.
JP 2004-6093 A (page 2-12, FIG. 1-5)

  In the fuel processing apparatus described in Patent Document 1 described above, as shown in FIG. 3, the temperature of the shift catalyst unit 14 (or the selective oxidation catalyst unit 19) is an overtemperature threshold and an overtemperature threshold. The range of the predetermined range defined by the value can be controlled, and as shown in FIG. 4, the temperature of the shift catalyst unit 14 (or the selective oxidation catalyst unit 19) is the overheated threshold value. However, when the temperature of the shift catalyst unit 14 (or the selective oxidation catalyst unit 19) fluctuates across the overheat threshold, the setting of the steam carbon ratio has fluctuated greatly. . As a result, in the reforming section, even if the supplied amount of reforming fuel is the same, the amount of reforming water to be fed fluctuates, causing pressure fluctuations, methane conversion rate fluctuations, etc. As a result, there is a fear that it is difficult to supply a stable reformed gas, that is, to operate a stable reformer.

  The present invention has been made in order to solve the above-described problems, and is capable of suppressing pressure fluctuations, methane conversion fluctuations, etc., supplying a stable reformed gas, and capable of operating a stable reforming apparatus. An object is to provide an apparatus.

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 1 is that a reforming fuel and reforming water are supplied as reforming raw materials, and the supplied reforming fuel is supplied by a reforming catalyst. A reforming unit that generates and derives reformed gas containing hydrogen by reforming, an evaporation unit that heats and boiles reformed water and supplies the steam to the reforming unit, and a reforming unit A carbon monoxide reduction section for introducing carbonaceous gas and reducing carbon monoxide in the reformed gas, reformed fuel supply means for supplying reforming fuel to the reforming section, and reforming water to the reforming section A reforming water supply means for supplying, a reforming fuel supply amount deriving means for deriving a supply amount of the reforming fuel supplied by the reforming fuel supply means, and a steam carbon ratio of the reforming raw material Steam carbon ratio control instruction value deriving means for deriving the steam carbon ratio control instruction value of The reforming water supplied to the reforming unit based on the steam carbon ratio control instruction value derived by the carbon ratio control instruction value deriving means and the reforming fuel supply amount derived by the reforming fuel supply amount deriving means Target reforming water supply deriving means for deriving the target supply amount, and reforming water supply for controlling the reforming water supply means so as to be the target reforming water supply amount derived by the target reforming water supply amount deriving means And a steam carbon ratio control instruction value deriving means based on at least one of the reforming fuel supply amount, the temperature of the carbon monoxide reduction unit, and the temperature of the steam. The control instruction value is derived.

  Further, the structural feature of the invention according to claim 2 is the steam carbon ratio control instruction value according to claim 1, further comprising in-case temperature detecting means for detecting the temperature in the case in which the reformer is accommodated. The deriving means derives the steam carbon ratio control instruction value in consideration of the temperature in the casing detected by the temperature detecting means in the casing.

  Further, the structural feature of the invention according to claim 3 is that, in claim 1, the steam carbon ratio control instruction value deriving means is a first map showing a correlation between the fuel supply amount for reforming and the steam carbon ratio. Alternatively, a first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the reforming fuel supply amount deriving means is derived from the arithmetic expression, and the first steam carbon ratio control instruction value is calculated. The steam carbon ratio control instruction value is used.

  According to a fourth aspect of the present invention, in the first aspect, the steam carbon ratio control instruction value deriving means is a first map showing a correlation between the reforming fuel supply amount and the steam carbon ratio. Alternatively, a first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the reforming fuel supply amount deriving means is derived from the arithmetic expression, and the temperature and steam carbon ratio of the carbon monoxide reduction unit are derived. The second steam carbon ratio control instruction value corresponding to the temperature of the carbon monoxide reduction unit is derived from the second map or the arithmetic expression indicating the correlation with the first and second steam carbon ratio control instruction values. Is added to derive the steam carbon ratio control instruction value.

  Further, the structural feature of the invention according to claim 5 is that, in claim 1, the steam carbon ratio control instruction value deriving means is a first map showing a correlation between the fuel supply amount for reforming and the steam carbon ratio. Alternatively, the first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the reforming fuel supply amount deriving means is derived from the arithmetic expression, and the correlation between the steam temperature and the steam carbon ratio is derived. The third steam carbon ratio control instruction value corresponding to the temperature of the water vapor is derived from the third map or the calculation formula indicating the steam carbon ratio control by adding the first and third steam carbon ratio control instruction values. An indication value is derived.

  Further, the structural feature of the invention according to claim 6 is that, in claim 1, the steam carbon ratio control instruction value deriving means is a first map showing a correlation between the fuel supply amount for reforming and the steam carbon ratio. Alternatively, a first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the reforming fuel supply amount deriving means is derived from the arithmetic expression, and the temperature and steam carbon ratio of the carbon monoxide reduction unit are derived. The second steam carbon ratio control instruction value corresponding to the temperature of the carbon monoxide reduction unit is derived from the second map or the arithmetic expression showing the correlation with the water vapor, and the correlation between the steam temperature and the steam carbon ratio is obtained. A third steam carbon ratio control instruction value corresponding to the temperature of the water vapor is derived from the third map or arithmetic expression shown, and the first to third steam carbon ratio control instruction values are added to the steam carbon. And to derive the ratio control instruction value.

  Further, the structural feature of the invention according to claim 7 is that in claim 1, the steam carbon ratio control instruction value deriving means is a correlation between the temperature in the housing in which the reformer is accommodated and the steam carbon ratio. The fourth steam carbon ratio control instruction value corresponding to the temperature in the housing is derived from the fourth map or the calculation expression indicating the steam carbon ratio control instruction in consideration of the fourth steam carbon ratio control instruction value. Deriving a value.

  Further, the structural feature of the invention according to claim 8 is that, in any one of claims 3 to 7, each correlation with the steam carbon ratio indicated by each map or arithmetic expression is continuous. It is.

  Further, the structural feature of the invention according to claim 9 is that, according to any one of claims 3 to 7, each correlation with the steam carbon ratio indicated by each map or arithmetic expression is the first in a normal state. It has not only a relationship but also a second relationship different from this first relationship.

  In the invention according to claim 1 configured as described above, the steam carbon ratio control instruction value derivation means is based on at least one of the reforming fuel supply amount, the temperature of the carbon monoxide reduction unit, and the temperature of the steam. Deriving the steam carbon ratio control instruction value, the reforming fuel supply amount deriving means derives the reforming fuel supply amount supplied by the reforming fuel supply means, and the target reforming water supply amount deriving means, A target supply amount of reforming water to be supplied to the reforming unit is derived based on the previously derived steam carbon ratio control instruction value and the reforming fuel supply amount, and the reforming water supply control means The reforming water supply unit is controlled so that the target reforming water supply amount derived by the supply amount deriving unit is obtained. As a result, when the supply amount of the reforming fuel supplied to the reforming unit changes, the supply amount of the reforming water supplied is adjusted according to the change in the supply amount of the reforming fuel to be supplied. Therefore, pressure fluctuation, methane conversion rate fluctuation, and the like are suppressed, and as a result, stable supply of reformed gas, that is, stable operation of the reformer can be realized. In addition, when the temperature of the carbon monoxide reduction unit fluctuates, the amount of reforming water supplied is adjusted in accordance with the temperature fluctuation of the carbon monoxide reduction unit. Therefore, it is possible to maintain a proper supply of reformed gas, that is, a more stable operation of the reformer. Furthermore, when the steam temperature fluctuates, the amount of reformed water supplied is adjusted according to the steam temperature fluctuation, so that steam, i.e. reformed water, can be properly supplied and more stable. Supply of the reformed gas, that is, more stable operation of the reformer can be realized.

  In the invention according to claim 2 configured as described above, in the invention according to claim 1, the steam carbon ratio control instruction value deriving means includes the steam in the casing detected by the casing temperature detecting means. By deriving the carbon ratio control instruction value, the amount of reforming water supplied to the reforming unit is adjusted in consideration of the temperature inside the housing in which the reformer is accommodated, so that the environmental temperature is Even if it fluctuates, stable supply of reformed gas, that is, stable operation of the reformer can be realized.

  In the invention according to claim 3 configured as described above, in the invention according to claim 1, the steam carbon ratio control instruction value deriving means shows the correlation between the reforming fuel supply amount and the steam carbon ratio. A first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the reforming fuel supply amount deriving means is derived from the map or arithmetic expression of 1, and this first steam carbon ratio control is derived. Since the instruction value is the steam carbon ratio control instruction value, the target supply amount of reforming water can be easily and reliably derived, and the reforming water supply means can be controlled so as to be the target reforming water supply amount. .

  In the invention according to claim 4 configured as described above, in the invention according to claim 1, the steam carbon ratio control instruction value deriving means shows a correlation between the fuel supply amount for reforming and the steam carbon ratio. A first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the reforming fuel supply amount deriving means is derived from the map or the arithmetic expression of 1, and the temperature of the carbon monoxide reduction unit is calculated. A second steam carbon ratio control instruction value corresponding to the temperature of the carbon monoxide reduction unit is derived from the second map or calculation expression showing the correlation with the steam carbon ratio, and the first and second steam carbon ratios are derived. Since the steam carbon ratio control instruction value is derived by adding the control instruction value, the target supply amount of reforming water is easily and reliably derived, and the reforming water supply means is provided so as to obtain the target reforming water supply amount. control Rukoto can.

  In the invention according to claim 5 configured as described above, in the invention according to claim 1, the steam carbon ratio control instruction value deriving means shows a correlation between the reforming fuel supply amount and the steam carbon ratio. The first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the reforming fuel supply amount deriving means is derived from the map or the arithmetic expression of 1, and the steam temperature and the steam carbon ratio are calculated. The third steam carbon ratio control instruction value corresponding to the temperature of the water vapor is derived from the third map or the arithmetic expression showing the correlation of the steam, and the first and third steam carbon ratio control instruction values are added and steam is added. Since the carbon ratio control instruction value is derived, the target supply amount of reforming water can be derived easily and reliably, and the reforming water supply means can be controlled to achieve the target reforming water supply amount.

  In the invention according to claim 6 configured as described above, in the invention according to claim 1, the steam carbon ratio control instruction value deriving means shows a correlation between the fuel supply amount for reforming and the steam carbon ratio. A first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the reforming fuel supply amount deriving means is derived from the map or the arithmetic expression of 1, and the temperature of the carbon monoxide reduction unit is calculated. A second steam carbon ratio control instruction value corresponding to the temperature of the carbon monoxide reduction unit is derived from the second map or the arithmetic expression indicating the correlation with the steam carbon ratio, and the steam temperature and the steam carbon ratio are calculated. A third steam carbon ratio control instruction value corresponding to the temperature of the water vapor is derived from the third map or calculation expression showing the correlation, and the first to third steam carbon ratio control instruction values are added. Because deriving a steam carbon ratio control instruction value each, easily and reliably to derive the target supply amount of the reforming water can be controlled reforming water supply means so that the target reforming water supply amount.

  In the invention according to claim 7 configured as described above, in the invention according to claim 1, the steam carbon ratio control instruction value deriving means includes the temperature in the casing in which the reformer is accommodated and the steam carbon ratio. The fourth steam carbon ratio control instruction value corresponding to the temperature in the housing is derived from the fourth map or the arithmetic expression indicating the correlation of the steam, and the steam carbon ratio control instruction value is also taken into account in consideration of the steam carbon ratio control instruction value. Since the ratio control instruction value is derived, the target supply amount of reforming water can be derived easily and reliably, and the reforming water supply means can be controlled so as to achieve the target reforming water supply amount.

  In the invention according to claim 8 configured as described above, in the invention according to any one of claims 3 to 7, each correlation with the steam carbon ratio indicated by each map or arithmetic expression is continuous. Therefore, the steam carbon ratio derived by the steam carbon ratio control instruction value deriving means changes continuously without making a steep change. Therefore, a sharp change in the amount of reformed water supplied is suppressed, and pressure fluctuations, methane conversion fluctuations, etc. are suppressed, resulting in stable reformed gas supply, that is, stable reformer operation. can do.

  In the invention according to claim 9 configured as described above, in the invention according to any one of claims 3 to 7, each correlation with the steam carbon ratio indicated by each map or arithmetic expression is normal. In addition to this first relationship, there is also a second relationship different from this first relationship, so during normal operation, the steam carbon ratio is derived based on the first relationship during normal operation and the target supply amount of reforming water is derived, The reforming water supply means can be controlled to achieve the target reforming water supply amount. In addition, if the second relationship is set so as to show the relationship when the reforming water flow rate is abnormally reduced, the steam carbon ratio is derived based on the second relationship and the target supply amount of the reforming water is determined at the time of the abnormality. By deriving and controlling the reforming water supply means so as to achieve the target reforming water supply amount, even if an abnormal time occurs, it can be dealt with accurately without providing other control means.

  Hereinafter, an embodiment of a fuel cell system to which a reformer according to the present invention is applied will be described. FIG. 1 is a schematic diagram showing an outline of this fuel cell system. As shown in FIG. 1, the fuel cell system includes a fuel cell 10 and a steam reforming reformer 20 that generates a reformed gas containing hydrogen gas necessary for the fuel cell 10. The fuel cell 10 includes a fuel electrode 11 and an air electrode 12, and generates power using the reformed gas supplied to the fuel electrode 11 and the air (cathode air) supplied to the air electrode 12.

  An inverter (power converter) 13 is connected to the fuel cell 10. The inverter 13 converts the power generation output (power generation current) of the fuel cell 10 into AC power (AC current) and supplies it to the power usage place 15 as a user destination via the power transmission line 14. A load device (not shown) which is an electric appliance such as a light, an iron, a TV, a washing machine, an electric kotatsu, an electric carpet, an air conditioner, and a refrigerator is installed in the power use place 15, and the AC supplied from the inverter 13 Electric power is supplied to the load device as needed. The power line 14 connecting the inverter 13 and the power use place 15 is also connected to the grid power source 16 of the power company (system interconnection), and the total power consumption of the load device exceeds the power generation output of the fuel cell 10. In such a case, the insufficient power is received from the system power supply 16 and compensated. The inverter 13 also has a function of measuring the direct current value input from the fuel cell 10 (output current detection means for detecting the output current of the fuel cell 10), and outputs a measurement signal to the control device 30. It has become. The wattmeter 15 a is user load power detection means for detecting user load power (user power consumption), detects the total power consumption of all the load devices used in the power usage location 15, and outputs the total power consumption to the control device 30. It is supposed to be.

  The reformer 20 includes a reforming unit 21, a cooling unit 22, a carbon monoxide shift reaction unit (hereinafter referred to as a CO shift unit) 23, a carbon monoxide selective oxidation unit (hereinafter referred to as a CO selective oxidation unit) 24, a combustion. The unit 25 and the evaporation unit 26 are included.

  The reforming unit 21 generates and derives a reformed gas from a mixed gas of fuel and water vapor supplied from the outside. Examples of the fuel include natural gas, LPG, kerosene, gasoline, methanol, and the like. In the present embodiment, description will be made on natural gas. The reforming portion 21 is formed in a bottomed cylindrical shape, and is formed of an outer flow passage 21a1 and an annular inner flow passage 21a2 each formed in an annular shape. The return channel 21a is provided.

  The return channel 21 a of the reforming unit 21 is filled with a catalyst 21 b (for example, a Ru or Ni-based catalyst), and is introduced from the reforming fuel introduced from the fuel supply pipe 41 and the water vapor supply pipe 52. The mixed gas with the steam is reacted and reformed by the catalyst 21b to generate hydrogen gas and carbon monoxide gas (so-called steam reforming reaction). At the same time, a so-called carbon monoxide shift reaction occurs in which carbon monoxide generated in the steam reforming reaction reacts with steam to transform into hydrogen gas and carbon dioxide. These generated gases (so-called reformed gas) are led to a cooling unit (heat exchange unit) 22. The steam reforming reaction is an endothermic reaction, and the carbon monoxide shift reaction is an exothermic reaction. The reforming fuel and reforming water are reforming raw materials.

  The cooling unit 22 is a heat exchanger in which heat exchange is performed between the reformed gas derived from the reforming unit 21 and a mixed gas of reforming fuel and reforming water (steam). The temperature of the reformed gas is lowered by a low-temperature mixed gas and led out to the CO shift unit 23, and the mixed gas is heated by the reformed gas and led out to the reforming unit 21. Specifically, a fuel supply pipe 41 connected to a fuel supply source Sf (for example, a city gas pipe) is connected to the cooling unit 22, and reforming fuel is supplied from the fuel supply source Sf. The fuel supply pipe 41 is provided with a first fuel valve 42, a fuel pump 43, a reforming fuel flow meter 85, a desulfurizer 44, and a second fuel valve 45 in order from the upstream. The first and second fuel valves 42 and 45 open and close the fuel supply pipe 41 according to commands from the control device 30. The fuel pump 43 sucks the reforming fuel supplied from the fuel supply source Sf and discharges it to the reforming unit 21, and adjusts the reforming fuel supply amount according to a command from the control device 30. The reforming fuel flow meter 85 detects the supply (input) amount of the reforming fuel supplied (input) to the reforming unit 21, and the detection signal is output to the control device 30. ing. The desulfurizer 44 removes sulfur (for example, sulfur compounds) in the reforming fuel. Thereby, the sulfur content is removed from the reforming fuel and supplied to the reforming unit 21.

  Further, a steam supply pipe 52 connected to the evaporation section 26 is connected between the second fuel valve 45 of the fuel supply pipe 41 and the cooling section 22, and the steam supplied from the evaporation section 26 becomes reforming fuel. It is mixed and supplied to the reforming unit 21 through the cooling unit 22. A water supply pipe 51 connected to a water tank Sw that is a reforming water supply source is connected to the evaporation unit 26. The water supply pipe 51 is provided with a water pump 53, a reforming water flow meter 86, and a water valve 54 in order from the upstream. The water pump 53 sucks the reformed water supplied from the water tank Sw and discharges it to the evaporation unit 26, and adjusts the reformed water supply amount according to a command from the control device 30. The reforming water flow meter 86 detects the supply (input) amount of the reforming water supplied (input) to the reforming unit 21, and a detection signal is output to the control device 30. . The water valve 54 opens and closes the water supply pipe 51 according to a command from the control device 30.

  The evaporation section 26 heats and boiles the reformed water to generate water vapor and supplies the steam to the reforming section 21 via the cooling section 22. The evaporation section 26 is formed in a cylindrical shape and has a first shape of the combustion gas channel 27. 2 The outer peripheral flow path 27c is provided so as to cover the outer peripheral wall. The evaporation section 26 has a water supply pipe 51 and a water vapor supply pipe 52 connected to a lower side wall surface and an upper side wall surface, respectively, and water introduced from the water supply pipe 51 circulates in the evaporation section 26 and is heated to generate water vapor and Thus, the water is supplied to the water vapor supply pipe 52. As a result, water (for example, 20 ° C.) that was at a low temperature at the time of introduction is heat-exchanged with the combustion gas flowing through the second outer peripheral flow path 27c to be heated to a boiling state (100 ° C. or higher) and is derived at that temperature. It has become so. The evaporation unit 26 is provided with a temperature sensor 26 a that detects the internal temperature, and a detection signal is output to the control device 30. In addition, a temperature sensor 87 for detecting the temperature of the water vapor or the temperature of the mixed gas is provided in a portion of the water supply pipe 52 or the fuel supply pipe 41 downstream from the junction with the water vapor supply pipe 52, and the detection signal is It is output to the control device 30. Note that FIG. 1 shows a case where both of these temperature sensors are provided, but in actuality, either one may be provided.

  The CO shift unit 23 is a unit that reduces carbon monoxide in the reformed gas supplied from the reforming unit 21 through the cooling unit 22, that is, a carbon monoxide reducing unit. The CO shift unit 23 includes a cylindrical casing 23a and an inner cylinder 23b disposed coaxially within the casing 23a. The inner cylinder 23b has an upper end connected to the inner peripheral end of an annular support member 23c whose outer peripheral end is connected to the inner peripheral surface of the housing 23a. A reformed gas inlet 23a1 is provided on the upper surface of the housing 23a, and the other end of a connecting pipe 89 having one end connected to the CO selective oxidation unit 24 is connected to a side surface of the housing 23a. A catalyst 23d (for example, a Cu—Zn-based catalyst) is filled in the inner cylinder 23b of the CO shift portion 23 and between the inner cylinder 23b and the housing 23a. The CO shift unit 23 is provided with a temperature sensor 23e for detecting the temperature in the CO shift unit 23, for example, the temperature in the vicinity of the reformed gas introduction port of the CO shift unit 23, and the detection signal is sent to the control device 30. It is output. The temperature sensor 23e is preferably provided on the inlet 23a1 side in the reformed gas flow path in the CO shift unit 23. Thereby, compared with the case where the temperature sensor 23e is provided on the outlet side of the reformed gas flow path, the temperature of the catalyst 23d can be controlled with high responsiveness.

  In the CO shift unit 23 configured as described above, the reformed gas led out from the cooling unit 22 passes through the reformed gas introduction port 23a1 and passes through the catalyst 23d in the inner cylinder 23b, and is turned back to return the inner cylinder 23b. And is led to the CO selective oxidation unit 24 through the inside of the catalyst 23d between the casing 23a. At this time, a so-called carbon monoxide shift reaction occurs in which carbon monoxide and water vapor contained in the introduced reformed gas react with the catalyst 23d to be converted into hydrogen gas and carbon dioxide gas. This carbon monoxide shift reaction is an exothermic reaction.

  The CO selective oxidation unit 24 further reduces the carbon monoxide in the reformed gas supplied from the CO shift unit 23 and supplies it to the fuel cell 10, that is, a carbon monoxide reduction unit, and is formed in a cylindrical shape. Then, the outer peripheral wall of the evaporation part 26 is covered and provided. In this CO selective oxidation unit 24, a connecting pipe 89 and a reformed gas supply pipe 71 are respectively connected to a lower side wall surface and an upper side wall surface, and a catalyst 24a (for example, a Ru or Pt catalyst) is filled therein. The reformed gas introduced through the connection pipe 89 flows through the CO selective oxidation unit 24 and is led out from the reformed gas supply pipe 71. Further, a temperature sensor 24 b for detecting the temperature of the catalyst 24 a is provided in the CO selective oxidation unit 24, and a detection signal thereof is output to the control device 30.

  Further, the reforming gas supplied to the CO selective oxidation unit 24 is mixed with oxidizing air. That is, the connection pipe 89 is connected to the oxidation air supply pipe 61 connected to the air supply source Sa, and is supplied with oxidation air from the air supply source Sa (for example, the atmosphere). The oxidation air supply pipe 61 is provided with a filter 62, an air pump 63, and an air valve 64 in order from the upstream. The filter 62 filters air. The air pump 63 sucks in air supplied from the air supply source Sa and discharges it to the CO selective oxidation unit 24, and adjusts the air supply amount in accordance with a command from the control device 30. The air valve 64 opens and closes the oxidizing air supply pipe 61 according to a command from the control device 30. Thus, the oxidizing air is mixed with the reformed gas from the CO shift unit 23 and supplied to the CO selective oxidation unit 24.

  Therefore, carbon monoxide in the reformed gas introduced into the CO selective oxidation unit 24 reacts with oxygen in the oxidizing air to become carbon dioxide. This reaction is an exothermic reaction and is promoted by the catalyst 24a. Thereby, the reformed gas is derived by further reducing the carbon monoxide concentration (10 ppm or less) by the oxidation reaction, and is supplied to the fuel electrode 11 of the fuel cell 10.

  The combustion part 25 generates combustion gas for heating the reforming part 21 and supplying heat necessary for the steam reforming reaction. The lower end part is inserted into the inner peripheral wall of the reforming part 21. It is arranged with a space. The combustion gas flows from the inner peripheral flow path 27a along the inner peripheral wall of the reforming section 21, the first outer peripheral flow path 27b folded back from the inner peripheral flow path 27a and along the outer peripheral wall of the reforming section 21, and the first outer peripheral flow path 27b. It is folded and flows through the combustion gas passage 27 constituted by the second outer peripheral passage 27 c along the heat insulating portion 28, and is exhausted as combustion exhaust gas through the exhaust pipe 81. The combustion gas passage 27 is covered with a heat insulating portion 28, and the heat of the combustion gas flowing through the inner peripheral flow passage 27a and the first outer peripheral flow passage 27b is suppressed from radiating to the outside by the heat insulating portion 28, so that the reforming portion. The heat of the combustion gas flowing through the second outer circumferential flow path 27c is effectively utilized for heating the evaporation section 26 because heat dissipation to the first outer circumferential flow path 27b is suppressed by the heat insulating section 28.

  A combustion fuel supply pipe 47 branched from the fuel supply pipe 41 is connected to the combustion section 25 upstream of the fuel pump 43 so that combustion fuel is supplied. The combustion fuel supply pipe 47 is provided with a combustion fuel pump 48. The combustion fuel pump 48 sucks the combustion fuel supplied from the fuel supply source Sf and discharges it to the combustion unit 25, and adjusts the fuel supply amount for combustion according to a command from the control device 30. The combustion section 25 is connected to the other end of an off-gas supply pipe 72 whose one end is connected to the outlet of the fuel electrode 11, and the reformed gas from the reformer 20 is supplied during the start-up operation of the fuel cell 10. Anode off-gas supplied through the reformed gas supply pipe 71, the bypass pipe 73 and the off-gas supply pipe 72 and discharged from the fuel cell 10 during steady operation of the fuel cell 10 (containing unused hydrogen in the fuel electrode 11). Reformed gas) is supplied.

  Further, a combustion air supply pipe 65 branched from the oxidation air supply pipe 61 is connected to the combustion section 25 upstream of the air pump 63, and combustion for burning combustion fuel, reformed gas or anode off gas is performed. Combustion air, which is an oxidant gas, is supplied. The combustion air supply pipe 65 is provided with a combustion air pump 66. The combustion air pump 66 sucks the combustion air supplied from the air supply source Sa and discharges it to the combustion section 25, and is a control device. The combustion air supply amount is adjusted in accordance with 30 commands. When the combustion unit 25 is ignited by a command from the control device 30, the combustion fuel, the reformed gas, or the anode off-gas supplied to the combustion unit 25 is burned to generate a high-temperature combustion gas.

  A CO selective oxidation unit 24 is connected to the inlet of the fuel electrode 11 of the fuel cell 10 via a reformed gas supply pipe 71 so that the reformed gas is supplied to the fuel electrode 11. The combustion part 25 is connected to the outlet of the fuel electrode 11 via an off-gas supply pipe 72 so that anode off-gas discharged from the fuel cell 10 is supplied to the combustion part 25. The bypass pipe 73 bypasses the fuel cell 10 and directly connects the reformed gas supply pipe 71 and the offgas supply pipe 72. The reformed gas supply pipe 71 is provided with a first reformed gas valve 74 between the branch point of the bypass pipe 73 and the fuel cell 10. The off gas supply pipe 72 is provided with an off gas valve 75 between the junction with the bypass pipe 73 and the fuel cell 10. A second reformed gas valve 76 is provided in the bypass pipe 73. The first and second reformed gas valves 74 and 76 and the offgas valve 75 open and close the respective pipes and are controlled by the control device 30. During the start-up operation, the first reformed gas valve 74 and the offgas valve 75 are closed and the second reformed gas valve 76 is opened in order to avoid supplying reformed gas having a high carbon monoxide concentration from the reformer 20 to the fuel cell 10. During the steady operation, the first reformed gas valve 74 and the off-gas valve 75 are opened and the second reformed gas valve 76 is closed in order to supply the reformed gas from the reformer 20 to the fuel cell 10.

  The tip of a cathode air supply pipe 67 branched from the combustion air supply pipe 65 upstream of the air pump 66 is connected to the inlet of the air electrode 12 of the fuel cell 10. Air is supplied. The cathode air supply pipe 67 is provided with a cathode air pump 68 and a cathode air valve 69 in order from the upstream. The cathode air pump 68 sucks air supplied from the air supply source Sa and discharges it to the air electrode 12 of the fuel cell 10, and adjusts the cathode air supply amount in accordance with a command from the control device 30. . The cathode air valve 69 opens and closes the cathode air supply pipe 67 according to a command from the control device 30. Further, one end of an exhaust pipe 82 whose other end is opened to the outside is connected to the outlet of the air electrode 12 of the fuel cell 10.

  A reformed gas condenser 77, an anode offgas condenser 78, and a cathode offgas condenser 79 are provided in the middle of the reformed gas supply pipe 71, offgas supply pipe 72, and exhaust pipe 82, respectively. The reformed gas condenser 77 condenses water vapor in the reformed gas supplied to the fuel electrode 11 of the fuel cell 10 flowing in the reformed gas supply pipe 71. The anode offgas condenser 78 condenses water vapor in the anode offgas discharged from the fuel electrode 11 of the fuel cell 10 flowing in the offgas supply pipe 72. The cathode offgas condenser 79 condenses the water vapor in the cathode offgas discharged from the air electrode 12 of the fuel cell 10 flowing in the exhaust pipe 82. Each of the condensers 77 to 79 is provided with a refrigerant pipe through which a low-temperature liquid in a hot water tank (not shown) or a liquid cooled by a radiator and a cooling fan is supplied, and each gas is exchanged by heat exchange with the liquid. The water vapor inside is condensed.

  These condensers 77, 78, and 79 communicate with the pure water device 95 through the pipe 84, and the condensed water condensed in each of the condensers 77, 78, and 79 is led out to the pure water device 95 and collected. It has become so. The deionizer 95 converts the condensed water supplied from each of the condensers 77, 78, and 79, that is, recovered water, into pure water using a built-in ion exchange resin. The purified water is led to the water tank Sw. To do. A water supply pipe 91 for introducing makeup water (tap water) supplied from a tap water supply source (for example, a water pipe) is connected to the water purifier 95, and the amount of water stored in the water purifier 95 is the lower limit water level. Below that, tap water is supplied.

  The fuel cell system described above is housed in the casing A, and a temperature sensor 88 for detecting the internal temperature is provided in the casing A so that the detection signal is output to the control device 30. It has become.

  Further, the fuel cell system includes a control device 30. The control device 30 includes the temperature sensors 23e, 24b, 26a, 87, 88, the flow meters 85, 86, the inverter 13, the voltmeter 15a, Each pump 43, 48, 53, 63, 66, 68, each valve 42, 45, 54, 64, 69, 74, 75, 76, and the combustion part 25 are connected (refer FIG. 2). The control device 30 includes a microcomputer (not shown), and the microcomputer includes an input / output interface, a CPU, a RAM, and a ROM (all not shown) connected through a bus. The CPU includes temperatures from the temperature sensors 23e, 24b, 26a, 87, and 88, supply amounts from the flow meters 85 and 86, output current from the inverter 13 (output current of the fuel cell 10), and power meter. The power consumption from 15a is input and each pump 43, 48, 53, 63, 66, 68, each valve 42, 45, 54, 64, 69, 74, 75, 76, and the combustion part 25 are controlled. Thus, the amounts of reforming fuel, combustion fuel, combustion air, and reforming water are controlled so as to achieve a desired output current (current / power consumed by the load device). The RAM temporarily stores variables necessary for executing the program, and the ROM stores the program.

  As shown in FIG. 3, the control device 30 includes an S / C control instruction value deriving unit 31 for deriving a steam carbon ratio control instruction value (hereinafter referred to as an S / C control instruction value), and an S / C control instruction value. Based on the S / C control instruction value derived by the deriving unit 31 and the reforming fuel supply amount detected by the reforming fuel flow meter 85 which is a reforming fuel supply amount deriving unit, the reforming unit 21 receives the reforming fuel supply amount. A target reforming water supply amount deriving unit 32 for deriving a target supply amount of reforming water to be supplied, and a reforming water supply so as to be the target reforming water supply amount derived by the target reforming water supply amount deriving unit 32 A reforming water supply control unit 33 for controlling the water pump 53 as means, and first to fourth map storage units 34a to 34d for storing first to fourth maps or arithmetic expressions (described later), respectively. ing. The S / C control instruction value is a ratio of the number of moles of steam (reformed water) and the number of moles of carbon in the reforming fuel respectively fed to the reforming unit 21 (number of moles of steam / reforming fuel). It is a control instruction value of the steam carbon ratio (S / C) of the raw material for reforming, which represents the number of moles of carbon in it.

  The S / C control instruction value deriving unit 31 derives a first S / C control instruction value based on the reforming fuel supply amount detected by the reforming fuel flow meter 85. An instruction value deriving unit 31a, a second S / C control instruction value deriving unit 31b for deriving a second S / C control instruction value based on the CO shift unit temperature detected by the temperature sensor 23e, and a temperature sensor 87 A third S / C control instruction value deriving unit 31c for deriving a third S / C control instruction value based on the water vapor temperature detected by, and a fourth based on the temperature in the housing detected by the temperature sensor 88. The fourth S / C control instruction value deriving unit 31d for deriving the S / C control instruction value of the first and third adders 31e to 31g.

  Specifically, the first S / C control instruction value deriving unit 31a inputs the reforming fuel supply amount, and the correlation between the reforming fuel supply amount and the S / C from the first map storage unit 34a. Is read out, and a first S / C control instruction value corresponding to the reforming fuel supply amount is derived from the first map or arithmetic expression, and output to the adder 31e. Yes.

  The second S / C control instruction value deriving unit 31b receives the CO shift unit temperature and receives a second map or calculation expression indicating the correlation between the CO shift unit temperature and the S / C from the second map storage unit 34b. , The second S / C control instruction value corresponding to the CO shift unit temperature is derived from the second map or arithmetic expression, and output to the adder 31e.

  The third S / C control instruction value deriving unit 31c inputs the water vapor temperature, reads a third map or an arithmetic expression indicating the correlation between the water vapor temperature and the S / C from the third map storage unit 34c, A third S / C control instruction value corresponding to the water vapor temperature is derived from the map 3 or the arithmetic expression and output to the adder 31f.

  The fourth S / C control instruction value deriving unit 31d inputs the temperature inside the casing, and reads the fourth map or the arithmetic expression indicating the correlation between the temperature inside the casing and the S / C from the fourth map storage unit 34d. The fourth S / C control instruction value corresponding to the temperature in the housing is derived from the fourth map or the arithmetic expression, and is output to the adder 31g.

  The adder 31e adds the first and second S / C control instruction values from the first and second S / C control instruction value deriving units 31a and 31b, and outputs the result to the adder 31f. . The adder 31f adds the total value of the first and second S / C control instruction values from the adder 31e and the third S / C control instruction value, and outputs the result to the adder 31g. The adder 31g adds the total value of the first to third S / C control instruction values from the adder 31e and the fourth S / C control instruction value to the target reforming water supply amount deriving unit 32. Output.

  As described above, the S / C control instruction value deriving unit 31 derives the S / C control instruction value by adding the derived first to fourth S / C control instruction values. Therefore, the S / C control instruction value deriving unit 31 derives the S / C control instruction value based on the reforming fuel supply amount, the CO shift unit temperature, the water vapor temperature, and the temperature in the housing.

  Further, the S / C control instruction value is set with the first S / C control instruction value as a basic value, and the first S / C control instruction value is set as an S / C control instruction value alone. It is also possible to add at least one of the second to fourth S / C control instruction values as a correction value to the first S / C control instruction value, which is the basic value, and to add the added value to the S / C It can also be set as a control instruction value.

  Next, the 1st-4th map or arithmetic expression memorize | stored in the 1st-4th map memory | storage parts 34a-34d is demonstrated with reference to FIGS. As shown in FIG. 4, the first map or arithmetic expression indicates the correlation between the reforming fuel supply amount (reforming 13A flow rate) and S / C. This relationship indicates that the S / C increases as the reforming fuel supply amount increases in the reforming fuel supply amount range corresponding to the range of the maximum output current (power) and the minimum output current (power) of the fuel cell 10. It decreases continuously within a predetermined range. This is due to the following reason. As the reforming fuel supply amount decreases, the amount of heat released from the reformer 20 relative to the reforming fuel supply amount relatively increases, and the combustion fuel supply amount decreases at the same rate as the reforming fuel supply amount. If it does, hydrogen generation efficiency (or fuel conversion rate) will fall. In order to compensate for the reduced hydrogen generation efficiency and maintain a stable system operation, the rate of decrease in the fuel supply amount for combustion is made smaller than the rate of decrease in the fuel supply amount for reforming. In this case, at a constant S / C, the temperature of the CO shift unit 23 and the CO selective oxidation unit 24 rises and deviates from an appropriate temperature range. Therefore, the S / C corresponding to the excessive fuel supply amount for combustion is increased to maintain the temperature balance.

In addition, the first map or the arithmetic expression indicates that the S / C and the reforming are within the range of the reforming fuel supply amount corresponding to the range of the maximum output current (power) and the minimum output current (power) of the fuel cell 10. The correlation of the fuel supply amount is continuous. Although it may be linear like FIG. 4, it is not restricted to this, For example, if it does not change extremely, such as a step shape, it may be a polygonal line shape.
Note that the amount of reforming fuel input is determined based on the amount of hydrogen to be generated by the reformer 20, and is basically determined based on the power generation output (power generation current) of the fuel cell 10. It is what is done.

As shown in FIG. 5, the second map or calculation expression indicates the correlation between the CO shift part temperature (for example, the shift part inlet temperature T1) and S / C. This relationship indicates that the S / C continuously increases as the CO shift portion inlet temperature T1 rises in a range where the CO shift portion inlet temperature T1 is equal to or higher than a predetermined temperature (200 ° C. in the present embodiment). It is like that. The predetermined temperature is set such that the temperature of the catalyst 23d of the CO shift unit 23 corresponds to the activation temperature range of the catalyst (for example, 250 ° C to 300 ° C). Accordingly, if the CO shift unit inlet temperature T1 is a predetermined temperature, the catalyst 23d of the CO shift unit 23 is in the activation temperature range. If the CO shift unit inlet temperature T1 exceeds the predetermined temperature, the catalyst 23d of the CO shift unit 23 is activated. Beyond the area. Therefore, when the CO shift unit inlet temperature T1 exceeds a predetermined temperature, the amount of reforming water input is increased as a heat receiving port in order to avoid an increase in the temperature of the CO shift unit 23.
Further, the second map or the calculation formula shows that the correlation between the S / C and the CO shift unit inlet temperature T1 is within a range where the CO shift unit inlet temperature T1 is equal to or higher than a predetermined temperature (200 ° C. in the present embodiment). Is continuous.

  Further, in the second map or the arithmetic expression, the correlation between the S / C and the CO shift portion inlet temperature T1 has not only the first relationship S at the normal time but also the second relationship T different from the first relationship S. It has become. The first relationship S indicates the relationship with S / C in the temperature range (200 ° C. ≦ T1 ≦ 240 ° C.) when the reformer 20 (or the fuel cell system) is operating normally. T is a temperature range in a case where an abnormality such as an increase in the amount of reforming water input and an increase in the temperature of the CO shift unit 23 occurs due to a failure of the water pump 53 that supplies reforming water, for example. The relationship with S / C in (240 degreeC <= T1 <= 270 degreeC) is shown. Thereby, when the reformer 20 (or the fuel cell system) is operating normally, the S / C corresponding to the CO shift unit inlet temperature T1 from the first relationship S indicating the relationship with the S / C in the temperature range. Can be derived. Further, when the reformer 20 (or the fuel cell system) is operating abnormally, the S / C corresponding to the CO shift portion inlet temperature T1 is calculated from the second relationship S indicating the relationship with the S / C in the temperature range. It is possible to control so that the reformed water is introduced as much as possible. Thereby, even if an abnormality occurs and the temperature of the catalyst 23d of the CO shift unit 23 exceeds the activation temperature range, damage to the catalyst 23d due to the temperature rise can be reduced.

Further, as shown in FIG. 6, the third map or the arithmetic expression indicates the correlation between the water vapor temperature (for example, the cooling section water inlet temperature T2) and S / C. This relationship is that S / C continuously increases as the cooling section water inlet temperature T2 rises in a range where the cooling section water inlet temperature T2 is equal to or higher than a predetermined temperature (100 ° C. in the present embodiment). It is like that. The predetermined temperature is set to the boiling point of water. Therefore, if the cooling unit water inlet temperature T2 is a predetermined temperature, the reforming water is appropriately supplied to the evaporation unit 26 to be steamed, and if the cooling unit water inlet temperature T2 exceeds the predetermined temperature, the evaporation unit 26 is sufficient. The reforming water is not supplied and the evaporation unit 26 is overheated. Therefore, when the cooling water inlet temperature T2 exceeds a predetermined temperature, the amount of the reforming water that is insufficient is increased in order to avoid overheating of the evaporator 26.
Further, the third map or calculation formula shows that the correlation between S / C and the cooling section water inlet temperature T2 is within a range where the cooling section water inlet temperature T2 is equal to or higher than a predetermined temperature (100 ° C. in the present embodiment). Is continuous.

Further, as shown in FIG. 7, the fourth map or the arithmetic expression indicates the correlation between the in-casing temperature T3 or the environmental temperature (atmosphere temperature) and S / C. This relationship is such that the S / C continuously increases as the housing temperature T3 rises in the range where the housing temperature T3 is equal to or higher than a predetermined temperature (50 ° C. in the present embodiment). Yes. The predetermined temperature is set to a temperature at which the heat dissipation efficiency in the housing A from the reformer 20 becomes worse when the housing temperature T3 exceeds the temperature. Therefore, if the in-casing temperature T3 is lower than the predetermined temperature, the heat dissipation efficiency is not bad, and therefore it is not necessary to take away the amount of heat in the reforming apparatus 20. However, if the in-casing temperature T3 exceeds the predetermined temperature, the reforming apparatus 20 You need to take away the extra heat inside. Therefore, when the in-casing temperature T3 exceeds a predetermined temperature, the amount of reforming water input is increased so as to take away excess heat.
Further, in the fourth map or arithmetic expression, the correlation between S / C and the casing internal temperature T3 is continuous in a range where the casing internal temperature T3 is equal to or higher than a predetermined temperature (50 ° C. in the present embodiment). is there.

  The operation of the fuel cell system described above will be described. The case where the above-described fuel cell system has a specification in which the S / C continuously decreases within a predetermined range as the reforming fuel supply amount increases will be described. When a start switch (not shown) is turned on at time t0, control device 30 starts the start-up operation of the fuel cell system. The control device 30 closes the first reformed gas valve 74 and the off-gas valve 75, opens the second reformed gas valve 76, connects the CO selective oxidation unit 24 to the combustion unit 25, opens the first fuel valve 42, and opens the second fuel valve. 45 is closed and the combustion fuel pump 48 and the combustion air pump 66 are driven to supply combustion fuel and combustion air to the combustion unit 25 to ignite the combustion unit 25. As a result, the combustion fuel is combusted and the combustion gas flows through the combustion gas flow path 27, and the reforming catalyst 21 a and the evaporation unit 26 in the reforming unit 21 are heated by the combustion gas.

  The control device 30 detects the temperature of the evaporation unit 26 by the temperature sensor 26a, and when the detected temperature is equal to or higher than the first predetermined temperature Th1 (time t1), the water valve 54 is opened and the water pump 53 is driven. The water in the water tank Sw is supplied to the reforming unit 21 through the evaporation unit 26 by a predetermined flow rate.

  The control device 30 starts counting the timer from the time (time t1) when the temperature of the evaporation unit 26 becomes equal to or higher than the predetermined temperature Th1. If the timer is equal to or longer than the first predetermined time T1 (for example, 1 minute), the second fuel valve 45 is opened to drive the fuel pump 43 to supply the fuel from the fuel supply source Sf to the reforming unit 21 by a predetermined flow rate. The air valve 64 is opened to drive the air pump 63 to supply the air from the air supply source Sa to the CO selective oxidation unit 24 by a predetermined flow rate (predetermined supply amount). Thus, the reformed fuel and steam mixed gas are supplied to the reforming unit 21, and the reforming unit 21 generates the reformed gas by causing the steam reforming reaction and the carbon monoxide shift reaction described above. The reformed gas derived from the reforming unit 21 is derived from the CO selective oxidizing unit 24 after the carbon monoxide gas is reduced by the CO shift unit 23 and the CO selective oxidizing unit 24, supplied to the combustion unit 25 and burned. The

  Thus, during the generation of the reformed gas, the control device 30 detects the temperature of the catalyst 24a of the CO selective oxidation unit 24 by the temperature sensor 24b, and if this detected temperature is equal to or higher than the second predetermined temperature Th2 ( At time t4), the first reformed gas valve 74 and the off-gas valve 75 are opened and the second reformed gas valve 76 is closed to connect the CO selective oxidation unit 24 to the inlet of the fuel electrode 11 of the fuel cell 10 and to guide the fuel electrode 11. The outlet is connected to the combustion unit 25. Thereby, the start-up operation for warming up the fuel cell system is completed, and then the steady operation is started.

  When the control device 30 starts a steady operation (an operation mode in which the fuel cell 10 generates power), the amount of hydrogen generated in the reformer 20 becomes a predetermined amount, that is, the output current of the fuel cell system is the power usage place 15. The reforming fuel, the combustion fuel, the combustion air, the oxidation air, the cathode air, and the reforming water are supplied so as to obtain a desired output current determined based on the current and power consumed in It has become. The control device 30 calculates the target reforming fuel supply amount so that the hydrogen amount becomes a predetermined amount, drives the fuel pump 43 so as to obtain the supply amount, and the reforming detected by the reforming fuel flow meter 85. The target reforming water supply amount is calculated based on the fuel supply amount for the engine and the S / C control instruction value, and the water pump 53 is driven so as to obtain the supply amount. When the amount of heat energy is insufficient or during the start-up operation, the amount of combustion fuel supplied to the combustion section 25 is calculated, and the combustion fuel pump 48 is driven so that the amount supplied becomes the reforming amount. The amount of combustion air supplied is calculated based on the amount of fuel supplied for the combustion, and the combustion air pump 66 is driven so as to obtain the amount supplied. To calculate the supply amount Then, the air pump 63 is driven, and the cathode air pump 68 is driven so as to calculate the supply amount of cathode air suitable for reacting with the reformed gas supplied from the reformer 20 and to obtain the supply amount. ing. When the stop switch is pressed, the fuel cell system stops.

  Further, calculation of the target reforming water supply amount and supply of reforming water will be described in detail. In the control device 30, first, the S / C control instruction value deriving unit 31 derives the S / C control instruction value. Specifically, the first S / C control instruction value deriving unit 31a determines the first map or the arithmetic expression based on the reforming fuel supply amount detected by the reforming fuel flow meter 85. An S / C control instruction value is derived. The second S / C control instruction value deriving unit 31b derives the second S / C control instruction value from the second map or the arithmetic expression according to the CO shift unit temperature detected by the temperature sensor 23e. The third S / C control instruction value deriving unit 31c derives the third S / C control instruction value from the third map or the arithmetic expression according to the water vapor temperature detected by the temperature sensor 87. The fourth S / C control instruction value deriving unit 31d derives the fourth S / C control instruction value from the fourth map or the arithmetic expression according to the temperature inside the casing detected by the temperature sensor 88. Each adder 31e to 31g adds the first to fourth S / C control instruction values to derive the S / C control instruction value.

  Then, the target reforming water supply amount deriving unit 32 has a reforming fuel flow meter 85 which is a S / C control instruction value derived by the S / C control instruction value deriving unit 31 and a reforming fuel supply amount deriving unit. A target supply amount of reforming water to be supplied to the reforming unit 21 is derived based on the reforming fuel supply amount detected by the above. Then, the reforming water supply control unit 33 controls the water pump 53 that is the reforming water supply means so that the target reforming water supply amount derived by the target reforming water supply amount deriving unit 32 is obtained.

  As is clear from the above description, in this embodiment, even when the supply amount of the reforming fuel supplied to the reforming unit 21 fluctuates, the supplied amount of reforming water is supplied. Therefore, pressure fluctuations, methane conversion fluctuations, etc. are suppressed, resulting in stable reformed gas supply, that is, stable reformer operation. be able to. Further, since the supply amount of the reforming water to be input is adjusted directly according to the fluctuation of the supply amount of the reforming fuel to be input, the reformer can be controlled with high responsiveness.

  In addition, the amount of reforming water supplied to the reforming unit 21 is adjusted in accordance with the change in the amount of reforming fuel supplied, and the temperature of the CO shift unit 23 also varies. Since adjustment is made with consideration, the catalyst temperature of the CO shift unit 23 can be kept appropriate, and more stable supply of reformed gas, that is, more stable operation of the reformer can be realized.

  In addition, the amount of reforming water supplied to the reforming unit 21 is adjusted according to fluctuations in the amount of reforming fuel supplied, and further supplied to the reforming unit 21. Since the temperature fluctuation of the water vapor is adjusted and adjusted, the water vapor, that is, the reformed water can be properly supplied, and the more stable supply of the reformed gas, that is, the more stable operation of the reformer can be realized. .

  Further, since the supply amount of the reforming water supplied to the reforming unit 21 is adjusted in consideration of the temperature in the casing A in which the reforming device 20 is accommodated, the environmental temperature (atmosphere temperature) varies. Even in this case, stable supply of reformed gas, that is, stable operation of the reformer can be realized.

  In addition, the S / C control instruction value deriving unit 31 detects the reform detected by the reforming fuel flow meter 85 from the first map or the arithmetic expression indicating the correlation between the reforming fuel supply amount and the S / C. A first S / C control instruction value corresponding to the quantity of fuel for quality is derived, and is detected by the temperature sensor 23e from the second map or arithmetic expression indicating the correlation between the CO shift portion temperature and the S / C. The second S / C control instruction value corresponding to the CO shift portion temperature is derived, and the water vapor detected by the temperature sensor 87 from the third map or the arithmetic expression indicating the correlation between the water vapor temperature and the S / C. A third S / C control instruction value corresponding to the temperature is derived, and the temperature inside the casing detected by the temperature sensor 88 is calculated from the fourth map or arithmetic expression indicating the correlation between the temperature inside the casing and the S / C. A corresponding fourth S / C control instruction value is derived, and the first to fourth Since the S / C control instruction value is derived by adding the / C control instruction value, the target supply amount of reforming water is easily and reliably derived, and the water pump 53 is set so as to obtain the target reforming water supply amount. Can be controlled.

  In addition, since each correlation with the S / C indicated by the first to fourth maps or arithmetic expressions is continuous, the S / C derived by the S / C control instruction value deriving unit 31 has a steep change. It changes continuously without doing. Therefore, a sharp change in the amount of reformed water supplied is suppressed, and pressure fluctuations, methane conversion fluctuations, etc. are suppressed, resulting in stable reformed gas supply, that is, stable reformer operation. can do.

  In addition, since the correlation with S / C indicated by the second map or the arithmetic expression has not only the first relationship S at the normal time but also the second relationship T different from the first relationship S, Based on the first relationship S, the S / C is derived to derive the target supply amount of reforming water, and the water pump 53 can be controlled to achieve the target reforming water supply amount. Further, if the second relationship T is set so as to indicate a relationship when the reforming water flow rate is abnormally reduced, the S / C is derived based on the second relationship T and the target supply of the reforming water is obtained at the time of the abnormality. By deriving the amount and controlling the reforming water supply means so that it becomes the target reforming water supply amount, even if an abnormal time occurs, it can be dealt with accurately without providing other control means. it can.

  In the above embodiment, the reforming fuel flow meter 85 is used as the reforming fuel supply amount deriving means. Instead, a method of deriving (estimating) based on other parameters is employed. May be.

  In the above embodiment, the second S / C control instruction value deriving unit 31b derives the second S / C control instruction value based on the temperature of the CO shift unit 23. The second S / C control instruction value may be derived based on the temperature of the carbon monoxide reduction unit, for example, the CO selective oxidation unit 24.

  Further, in the above embodiment, the correlation with S / C indicated by the second map or the arithmetic expression has not only the first relationship S at normal time but also the second relationship S different from the first relationship S. However, the third and fourth maps or arithmetic expressions may have a first relationship and a second relationship.

  In the above-described embodiment, the fuel pump 43 is used as the reforming fuel supply means, the combustion fuel pump 48 is used as the combustion fuel supply means, and the air pumps 63, 66, and 68 are used as the oxidant gas supply means. However, instead of these, a blower (blower) may be adopted.

  In the above-described embodiment, the fuel cell system has a specification in which the S / C continuously decreases within a predetermined range as the reforming fuel supply amount increases, but is not limited thereto. The present invention can also be applied to the case where the fuel cell system has a specification in which the S / C is constant even when the reforming fuel supply amount increases.

  In this case, in FIG. 3, the control device 30 deletes the first steam carbon ratio control instruction value deriving unit 31a and the first map storage unit 34a, and the reforming fuel supply amount is derived as the target reforming water supply amount. It is supplied only to the section 32. Further, the adder 31e receives the fifth S / C control instruction value instead of the first S / C control instruction value from the first steam carbon ratio control instruction value deriving unit 31a, and receives the fifth S / C control instruction value. 2, the second S / C control instruction value from the steam carbon ratio control instruction value deriving unit 31 b is added and output to the adder 31 f. The fifth S / C control instruction value is stored in a storage unit (not shown). The fifth S / C control instruction value is based on an ideal S / C calculated from a chemical formula of a chemical reaction such as a steam reforming reaction in the reforming unit 21, the CO shift unit 23, and the CO selective oxidation unit 24. This is a target S / C unique to the actual machine derived with reference to the capacity of the water pump 53 and the like.

  As a result, even when the fuel cell system has a specification in which the S / C is constant even when the reforming fuel supply amount increases, the S / C control instruction value deriving unit 31 performs the fifth S / C control. The S / C control instruction value is derived by adding the second to fourth S / C control instruction values to the instruction value. Therefore, since the S / C control instruction value is derived based on the temperature of the carbon monoxide reduction unit, the temperature of the steam, and the temperature in the housing, the amount of reformed water supplied is equal to the temperature of the carbon monoxide reduction unit. Fluctuations, water vapor temperature fluctuations, and the temperature inside the casing A are adjusted appropriately, so that pressure fluctuations, methane conversion fluctuations, etc. are suppressed. The operation of the quality device can be realized.

  Even when either the temperature of the carbon monoxide reduction unit or the temperature of the steam fluctuates, the amount of reformed water supplied is changed in the temperature of the carbon monoxide reduction unit or the temperature of the steam. Is adjusted appropriately.

1 is a schematic diagram showing an outline of an embodiment of a fuel cell system to which a reformer according to the present invention is applied. It is a block diagram which shows the reforming apparatus shown in FIG. It is a block diagram of the control apparatus shown in FIG. It is a 1st map which shows the correlation of the fuel supply amount for reforming, and S / C. It is a 2nd map which shows the correlation of CO shift part inlet_port | entrance temperature and S / C. It is a 3rd map which shows the correlation with a cooling water inlet temperature and S / C. It is a 4th map which shows the correlation of the temperature in a housing | casing, and S / C.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Fuel cell, 11 ... Fuel electrode, 12 ... Air electrode, 13 ... Inverter, 20 ... Reformer, 21 ... Reformer, 21a ... Return path, 21b ... Catalyst, 22 ... Cooling unit, 23 ... CO shift Part, 23d ... catalyst, 23e ... temperature sensor, 24 ... CO selective oxidation part, 24a ... catalyst, 24b ... temperature sensor, 25 ... combustion part, 26 ... evaporation part, 26a ... temperature sensor, 27 ... combustion gas flow path, 28 DESCRIPTION OF SYMBOLS ... Heat insulation part, 30 ... Control apparatus, 31 ... S / C control instruction value derivation part, 32 ... Target reforming water supply amount derivation part, 33 ... Reformation water supply control part, 41 ... Fuel supply pipe, 42 ... 1st Fuel valve, 43 ... Fuel pump, 44 ... Desulfurizer, 45 ... Second fuel valve, 47 ... Fuel supply pipe for combustion, 48 ... Fuel pump for combustion, 51 ... Water supply pipe, 52 ... Water supply pipe, 53 ... Water pump 54 ... Water valve, 61 ... Oxidation air supply pipe, DESCRIPTION OF SYMBOLS 2 ... Filter, 63 ... Air pump, 64 ... Air valve, 65 ... Combustion air supply pipe, 66 ... Combustion air pump, 67 ... Cathode air supply pipe, 68 ... Cathode air pump, 69 ... Cathode air valve 71 ... Reformed gas supply pipe, 72 ... Off gas supply pipe, 73 ... Bypass pipe, 74 ... First reformed gas valve, 75 ... Off gas valve, 76 ... Second reformed gas valve, 77, 78, 79 ... Condenser, 81, 82 ... exhaust pipe, 84 ... piping, 85 ... reforming fuel flow meter, 86 ... reforming water flow meter, 87, 88 ... temperature sensor, 89 ... connection pipe, 91 ... water supply pipe, 95 ... pure water device , A ... casing, Sa ... air supply source, Sf ... fuel supply source, Sw ... reformed water supply source.

Claims (9)

A reforming section for supplying reforming fuel and reforming water as reforming raw materials and reforming the supplied reforming fuel with a reforming catalyst to generate and derive reformed gas containing hydrogen; ,
An evaporating section for heating and boiling the reforming water and supplying the steam to the reforming section;
A carbon monoxide reduction unit that introduces the reformed gas from the reforming unit and reduces carbon monoxide in the reformed gas; and
Reformed fuel supply means for supplying the reforming fuel to the reforming section;
A reforming water supply means for supplying the reforming water to the reforming unit;
A reforming fuel supply amount deriving unit for deriving a supply amount of the reforming fuel supplied by the reforming fuel supply unit;
Steam carbon ratio control instruction value deriving means for deriving a steam carbon ratio control instruction value for controlling the steam carbon ratio of the reforming raw material;
Based on the steam carbon ratio control instruction value derived by the steam carbon ratio control instruction value deriving means and the reforming fuel supply amount derived by the reforming fuel supply amount deriving means, the fuel is supplied to the reforming unit. Target reforming water supply amount deriving means for deriving a target supply amount of reforming water;
A reforming apparatus comprising: reforming water supply control means for controlling the reforming water supply means so as to be the target reforming water supply quantity derived by the target reforming water supply quantity deriving means;
The steam carbon ratio control instruction value deriving means derives the steam carbon ratio control instruction value based on at least one of the reforming fuel supply amount, the temperature of the carbon monoxide reduction unit, and the temperature of the water vapor. A reformer characterized by. In Claim 1, further comprising a temperature detection means in the casing for detecting the temperature in the casing in which the reformer is accommodated,
The reforming apparatus characterized in that the steam carbon ratio control instruction value deriving means derives the steam carbon ratio control instruction value in consideration of the temperature in the casing detected by the temperature detection means in the casing.   2. The steam carbon ratio control instruction value deriving means according to claim 1, wherein the reforming fuel supply amount deriving unit derives the reforming fuel supply amount from a first map or an arithmetic expression indicating a correlation between the reforming fuel supply amount and a steam carbon ratio. A first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the means is derived, and the first steam carbon ratio control instruction value is used as the steam carbon ratio control instruction value. Reforming equipment.   2. The steam carbon ratio control instruction value deriving means according to claim 1, wherein the reforming fuel supply amount deriving unit derives the reforming fuel supply amount from a first map or an arithmetic expression indicating a correlation between the reforming fuel supply amount and a steam carbon ratio. A first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the means, and a second map indicating a correlation between the temperature of the carbon monoxide reduction unit and the steam carbon ratio, or A second steam carbon ratio control instruction value corresponding to the temperature of the carbon monoxide reduction unit is derived from an arithmetic expression, and the steam carbon ratio control is performed by adding the first and second steam carbon ratio control instruction values. A reformer characterized by deriving an indicated value.   2. The steam carbon ratio control instruction value deriving means according to claim 1, wherein the reforming fuel supply amount deriving unit derives the reforming fuel supply amount from a first map or an arithmetic expression indicating a correlation between the reforming fuel supply amount and a steam carbon ratio. A first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the means is derived, and from a third map or arithmetic expression showing a correlation between the temperature of the steam and the steam carbon ratio, A third steam carbon ratio control instruction value corresponding to the temperature of the water vapor is derived, and the steam carbon ratio control instruction value is derived by adding the first and third steam carbon ratio control instruction values. Reforming equipment.   2. The steam carbon ratio control instruction value deriving means according to claim 1, wherein the reforming fuel supply amount deriving unit derives the reforming fuel supply amount from a first map or an arithmetic expression indicating a correlation between the reforming fuel supply amount and a steam carbon ratio. A first steam carbon ratio control instruction value corresponding to the reforming fuel supply amount derived by the means, and a second map indicating a correlation between the temperature of the carbon monoxide reduction unit and the steam carbon ratio, or From the calculation formula, a second steam carbon ratio control instruction value corresponding to the temperature of the carbon monoxide reduction unit is derived, and from a third map or calculation formula showing the correlation between the temperature of the water vapor and the steam carbon ratio. Then, a third steam carbon ratio control instruction value corresponding to the temperature of the water vapor is derived, and the first to third steam carbon ratio control instruction values are added to add the steam carbon ratio control value. Reforming apparatus characterized by deriving an indication.   2. The steam carbon ratio control instruction value deriving means according to claim 1, wherein the steam carbon ratio control instruction value deriving unit is configured to calculate the inside of the casing from a fourth map or an arithmetic expression indicating a correlation between the temperature in the casing in which the reformer is accommodated and the steam carbon ratio. A reformer characterized by deriving a fourth steam carbon ratio control instruction value corresponding to the temperature of the gas, and deriving the steam carbon ratio control instruction value in consideration of the fourth steam carbon ratio control instruction value .   8. The reformer according to any one of claims 3 to 7, wherein each correlation with the steam carbon ratio indicated by each map or calculation formula is continuous.   8. The correlation in any one of claims 3 to 7, wherein each correlation with the steam carbon ratio indicated by each map or arithmetic expression is not only the first relation at normal time but also a second relation different from the first relation. A reformer characterized by also having.

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