JP2009277540A - Control method for fuel cell power generating system, and the fuel power generating system - Google Patents

Control method for fuel cell power generating system, and the fuel power generating system Download PDF

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JP2009277540A
JP2009277540A JP2008128430A JP2008128430A JP2009277540A JP 2009277540 A JP2009277540 A JP 2009277540A JP 2008128430 A JP2008128430 A JP 2008128430A JP 2008128430 A JP2008128430 A JP 2008128430A JP 2009277540 A JP2009277540 A JP 2009277540A
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fuel cell
load amount
power generation
auxiliary
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JP5359022B2 (en
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Kohei Sato
康平 佐藤
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Fuji Electric Co Ltd
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Fuji Electric Systems Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract

<P>PROBLEM TO BE SOLVED: To prevent output characteristics of a fuel cell from exceeding the tolerance, and affecting the fuel cell by adjusting the load volume of a heater for a steam separator. <P>SOLUTION: At self-support operation, power supply is performed in response to a load variation of a customer load 12, by adjusting the load volume of a cooling water heater 35 of the steam separator 24 and maintaining the sum total of the load volume of an auxiliary machinery load 3 and the load volume of the customer load 12 at a predetermined value. Although the adjustment of the load volume of the cooling water heater 35 may cause changing of the output characteristics of the fuel cell 1, the load volume of the cooling water heater 35 is readjusted, to be settled within the tolerance value, by monitoring the power generation current of the fuel cell 1 and pressure of the steam separator 24, so that adverse effects on the fuel cell body due to the exceeding of the tolerance of the output characteristics of the fuel cell 1 is avoided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、自立運転時に、負荷と補機負荷との負荷量の合計が所定値となるように補機負荷の負荷量を調整する燃料電池発電システムの制御方法及び燃料電池発電システムに関する。   The present invention relates to a control method for a fuel cell power generation system and a fuel cell power generation system that adjust the load amount of an auxiliary machine load so that the total load amount of the load and the auxiliary machine load becomes a predetermined value during self-sustained operation.

従来、電力系統と燃料電池発電装置とで連系して、電力供給を行うべき負荷に対して電力供給を行うようにした燃料電池発電システムが提案されている。この燃料電池発電システムにおいては、連系運転時には、燃料電池発電装置の発電出力を負荷に供給し、負荷への供給電力が不足する場合には電力系統から不足分を獲得してこれを供給し、逆に余剰分は電力系統に供給することで、負荷に対して過不足のない給電を行っている。   2. Description of the Related Art Conventionally, a fuel cell power generation system has been proposed in which a power system and a fuel cell power generation apparatus are linked to supply power to a load to be supplied with power. In this fuel cell power generation system, the power generation output of the fuel cell power generation device is supplied to the load during the interconnection operation, and when the power supply to the load is insufficient, the shortage is acquired from the power system and supplied. On the other hand, the surplus is supplied to the power system, so that the power is supplied to the load without excess or deficiency.

一方、電力系統から燃料電池発電装置及び負荷を解列して切り離し、燃料電池発電装置の発電出力により負荷への供給電力を賄う自立運転時には、負荷と、燃料電池発電装置内の電気ヒータ等といった負荷量可変の可変負荷との負荷量の合計が所定値となるように、可変負荷の負荷量を調整することで、負荷に負荷変動が生じた場合であっても、負荷に対して過不足なく、給電を行うようにしている（例えば、特許文献１参照）。
特開平１０−２２８９１９号公報 On the other hand, during the self-sustaining operation in which the fuel cell power generation device and the load are disconnected and disconnected from the power system and the power output from the fuel cell power generation device covers the power supplied to the load, the load, the electric heater in the fuel cell power generation device, etc. By adjusting the load amount of the variable load so that the total load amount with the variable load with variable load amount becomes the predetermined value, even if the load fluctuates, the load is excessive or insufficient Instead, power is supplied (for example, see Patent Document 1).
JP-A-10-228919

しかしながら、負荷量可変の可変負荷として、例えば前記特許文献１の第３の実施の形態に記載されているように、燃料電池本体の発熱を除去するための水蒸気分離器用の加熱器を適用した場合、負荷の負荷量変動に伴い加熱器の負荷量を変化させると、この変化に伴い水蒸気分離器の圧力が変動する。このため、この水蒸気分離器の圧力変動に伴い、燃料電池本体の発電特性が変化し、燃料電池の発電電流又は発電電圧が変動してしまうという問題がある。
そこで、この発明は、上記従来の未解決の問題点に着目してなされたものであり、自立運転時に、負荷の負荷量が変動した場合であっても、安定した発電を行うことの可能な燃料電池発電システムの制御方法及び燃料電池発電システムを提供することを目的としている。 However, as a variable load having a variable load amount, for example, as described in the third embodiment of Patent Document 1, a heater for a water vapor separator for removing heat generated in the fuel cell main body is applied. When the load amount of the heater is changed in accordance with the load amount variation of the load, the pressure of the steam separator fluctuates with this change. For this reason, the power generation characteristics of the fuel cell body change with the pressure fluctuation of the water vapor separator, and there is a problem that the power generation current or power generation voltage of the fuel cell changes.
Therefore, the present invention has been made by paying attention to the above-mentioned conventional unsolved problems, and can perform stable power generation even when the load amount of the load fluctuates during self-sustained operation. It is an object of the present invention to provide a control method for a fuel cell power generation system and a fuel cell power generation system.

上記目的を達成するために、本発明の請求項１に係る発明は、系統電源とは独立に燃料電池から負荷に電力供給を行う自立運転中は、前記負荷と補機負荷との負荷合計が所定値となるように前記補機負荷の負荷量を調整し、且つ前記補機負荷として、燃料電池本体に供給される水素リッチガス生成用の水蒸気を出力する水蒸気分離器の温度調節用加熱器を用いる燃料電池発電システムの制御方法であって、前記燃料電池の発電電力の出力特性が予め設定した出力特性の許容範囲に収まるように前記補機負荷の負荷量を調整する第１の負荷量調整ステップと、前記水蒸気分離器の圧力が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整する第２の負荷量調整ステップと、を備えることを特徴としている。   In order to achieve the above object, the invention according to claim 1 of the present invention is configured such that the load total of the load and the auxiliary load is determined during a self-sustained operation in which power is supplied from the fuel cell to the load independently of the system power supply. A heater for adjusting the temperature of the water vapor separator that adjusts the load amount of the auxiliary machine load so as to be a predetermined value and outputs, as the auxiliary machine load, water vapor for generating hydrogen rich gas supplied to the fuel cell main body. A control method for a fuel cell power generation system to be used, wherein the load amount of the auxiliary load is adjusted so that the output characteristic of the generated power of the fuel cell falls within a preset allowable range of the output characteristic. And a second load amount adjustment step of adjusting the load amount of the auxiliary load so that the pressure of the water vapor separator falls within a preset allowable range.

また、請求項２に係る発明は、前記第１の負荷量調整ステップ及び前記第２の負荷量調整ステップのうちの何れかを他方よりも優先することを特徴としている。
また、請求項３に係る発明は、前記第１の負荷量調整ステップを前記第２の負荷量調整ステップよりも優先することを特徴としている。
また、請求項４に係る発明は、前記第１の負荷量調整ステップでは、前記燃料電池の発電電流が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整することを特徴としている。 The invention according to claim 2 is characterized in that one of the first load amount adjustment step and the second load amount adjustment step has priority over the other.
The invention according to claim 3 is characterized in that the first load amount adjustment step has priority over the second load amount adjustment step.
The invention according to claim 4 is characterized in that, in the first load amount adjustment step, the load amount of the auxiliary load is adjusted so that the generated current of the fuel cell is within a preset allowable range. Yes.

また、請求項５に係る発明は、前記第１の負荷量調整ステップでは、前記燃料電池の発電電圧が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整することを特徴としている。
また、請求項６に係る発明は、前記第２の負荷量調整ステップでは、前記水蒸気分離器の水蒸気温度を検出し、前記水蒸気温度が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整することを特徴としている。
さらに、請求項７に係る発明は、前記第２の負荷量調整ステップでは、前記水蒸気分離器の水蒸気流量を検出し、前記水蒸気流量が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整することを特徴としている。 The invention according to claim 5 is characterized in that, in the first load amount adjustment step, the load amount of the auxiliary load is adjusted so that the power generation voltage of the fuel cell is within a preset allowable range. Yes.
Further, in the invention according to claim 6, in the second load amount adjustment step, the steam temperature of the steam separator is detected, and the load of the auxiliary load is set so that the steam temperature falls within a preset allowable range. It is characterized by adjusting the amount.
Further, in the invention according to claim 7, in the second load amount adjustment step, the steam flow rate of the steam separator is detected, and the load of the auxiliary load is set so that the steam flow rate falls within a preset allowable range. It is characterized by adjusting the amount.

また、本発明の請求項８に係る発明は、系統電源とは独立に燃料電池から負荷に電力供給を行う自立運転中は、前記負荷と補機負荷との負荷合計が所定値となるように前記補機負荷の負荷量を調整し、且つ前記補機負荷として、燃料電池本体に供給される水素リッチガス生成用の水蒸気を出力する水蒸気分離器の温度調節用加熱器を用いる燃料電池発電システムであって、前記燃料電池の発電電力の出力特性が予め設定した出力特性の許容範囲に収まるように前記補機負荷の負荷量を調整する第１の負荷量調整手段と、前記水蒸気分離器の圧力が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整する第２の負荷量調整手段と、を備えたことを特徴としている。   In the invention according to claim 8 of the present invention, during the self-sustained operation in which power is supplied from the fuel cell to the load independently of the system power supply, the total load of the load and the auxiliary load becomes a predetermined value. A fuel cell power generation system that uses a heater for adjusting the temperature of a steam separator that adjusts a load amount of the auxiliary load and outputs steam for generating hydrogen-rich gas supplied to a fuel cell body as the auxiliary load. A first load amount adjusting means for adjusting a load amount of the auxiliary load so that an output characteristic of the generated power of the fuel cell falls within a preset allowable range of the output characteristic; and a pressure of the steam separator Is provided with a second load amount adjusting means for adjusting the load amount of the auxiliary load so as to fall within a preset allowable range.

ここで、水蒸気分離器の温度調節用の加熱器の負荷量を調整すると、水蒸気分離器の圧力が変動するため、水蒸気分離器で発生された水蒸気を利用して生成される水素リッチガスの流量が変動し、この水素リッチガスを利用して発電を行う燃料電池の発電電力の出力特性が変動することになる。しかしながら、燃料電池の発電電力の出力特性を監視しこれが許容範囲に収まるように補機負荷の負荷量を調整し、また、燃料電池の出力特性の変動をもたらす水蒸気分離器の圧力を許容範囲に収まるように、補機負荷の負荷量を調整するため、燃料電池の発電電力の出力特性が許容範囲を超えて変動することを回避することができる。   Here, when the load amount of the heater for adjusting the temperature of the water vapor separator is adjusted, the pressure of the water vapor separator fluctuates. Therefore, the flow rate of the hydrogen rich gas generated using the water vapor generated in the water vapor separator is The output characteristics of the generated power of the fuel cell that generates power using this hydrogen-rich gas will fluctuate. However, the output characteristics of the power generated by the fuel cell are monitored, the load on the auxiliary load is adjusted so that this is within the allowable range, and the steam separator pressure that causes fluctuations in the output characteristics of the fuel cell is within the allowable range. Since the load amount of the auxiliary load is adjusted so as to be within the range, it is possible to avoid fluctuations in the output characteristics of the generated power of the fuel cell exceeding the allowable range.

特に、水蒸気分離器の圧力変動による影響が燃料電池の出力特性に現れるまでに応答遅れが生じるため、圧力変動が生じた時点では燃料電池本体に与える影響は小さい。一方、燃料電池の出力特性が変化した場合に燃料電池本体に与える影響は大きい。このため、燃料電池本体に与える影響の大きい、燃料電池の出力特性の調整を優先して行うことにより、燃料電池本体を効率よく保護することができる。   In particular, since a response delay occurs until the influence of the pressure fluctuation of the water vapor separator appears in the output characteristics of the fuel cell, the influence on the fuel cell main body is small when the pressure fluctuation occurs. On the other hand, when the output characteristics of the fuel cell change, the influence on the fuel cell main body is large. For this reason, the fuel cell body can be efficiently protected by prioritizing the adjustment of the output characteristics of the fuel cell, which has a large influence on the fuel cell body.

本発明によれば、負荷と燃料電池用の補機負荷との負荷合計が所定値となるように補機負荷としての水蒸気分離器の加熱器の負荷量を調整すると共に、燃料電池の発電電力の出力特性が許容範囲に収まるように補機負荷の負荷量を調整し、また、水蒸気分離器の圧力が許容範囲に収まるように補機負荷の負荷量を調整するため、自立運転時における負荷の負荷量変動に追従して電力供給を行うことができると共に、水蒸気分離器の加熱器の負荷量の変動に伴い燃料電池の出力特性が許容範囲を超えることを回避し、燃料電池の出力特性が許容範囲を超えることにより燃料電池本体が影響を受けることを回避することができる。
特に、燃料電池に実際に影響を及ぼすまでに応答遅れを有する水蒸気分離器の圧力の調整よりも、燃料電池本体に影響を及ぼしている燃料電池の出力特性の調整を優先して行うため、燃料電池本体の保護を効率よく行うことができる。 According to the present invention, the load amount of the heater of the steam separator as the auxiliary load is adjusted so that the total load of the load and the auxiliary load for the fuel cell becomes a predetermined value, and the generated power of the fuel cell is adjusted. In order to adjust the load of the auxiliary load so that the output characteristics of the steam generator are within the allowable range, and to adjust the load of the auxiliary load so that the pressure of the steam separator is within the allowable range, The power supply can be supplied following the fluctuation of the load amount of the fuel cell, and the output characteristics of the fuel cell can be avoided by exceeding the allowable range due to the fluctuation of the load amount of the heater of the steam separator. It is possible to avoid that the fuel cell main body is affected by exceeding the allowable range.
In particular, the adjustment of the output characteristics of the fuel cell affecting the fuel cell body is prioritized over the adjustment of the pressure of the water vapor separator that has a response delay until it actually affects the fuel cell. The battery body can be protected efficiently.

以下、本発明の実施の形態を説明する。
図１は、本発明を適用した燃料電池発電システム１０の概略構成を示すブロック図である。
図１の燃料電池発電システム１０は、直流電力を発電する燃料電池１と、この燃料電池１の発電出力を交流電力に変換するインバータ２と、燃料電池１内の各種補機や後述の電気ヒータ等の補機負荷３と、燃料電池発電システム１０を系統電源１１から切り離すための系統連系用遮断器４と、システム制御装置７と、を備える。 Embodiments of the present invention will be described below.
FIG. 1 is a block diagram showing a schematic configuration of a fuel cell power generation system 10 to which the present invention is applied.
A fuel cell power generation system 10 in FIG. 1 includes a fuel cell 1 that generates DC power, an inverter 2 that converts the power generation output of the fuel cell 1 into AC power, various auxiliary devices in the fuel cell 1, and an electric heater described later. And the like, a system interconnection circuit breaker 4 for disconnecting the fuel cell power generation system 10 from the system power supply 11, and a system control device 7.

燃料電池１の発電出力はインバータ２で交流電力に変換され、その一部は補機負荷３に供給されると共に、燃料電池発電システム１０の給電対象である顧客負荷１２に供給される。また、燃料電池１の発電出力の余剰分は、系統連系用遮断器４を介して系統電源１１に供給され、逆に、不足分は、系統連系用遮断器４を介して系統電源１１から顧客負荷１２に供給される。   The power generation output of the fuel cell 1 is converted into AC power by the inverter 2, and a part thereof is supplied to the auxiliary load 3 and also supplied to the customer load 12 that is a power supply target of the fuel cell power generation system 10. Further, the surplus of the power generation output of the fuel cell 1 is supplied to the system power supply 11 via the grid connection circuit breaker 4. Conversely, the shortage is supplied to the system power supply 11 via the system connection circuit breaker 4. To the customer load 12.

前記燃料電池１には、その発電出力を検出する電流センサ１ａが設けられている。また、補機負荷３及び顧客負荷１２のそれぞれには、負荷量を計測するための電力計等の負荷計測センサ３ａ及び１２ａが設けられている。これら電流センサ１ａ、負荷計測センサ３ａ及び１２ａのセンサ出力は、システム制御装置７に入力される。
システム制御装置７は、燃料電池１、インバータ２及び系統連系用遮断器４を制御する。 The fuel cell 1 is provided with a current sensor 1a for detecting the power generation output. Each of the auxiliary load 3 and the customer load 12 is provided with load measurement sensors 3a and 12a such as wattmeters for measuring the load amount. The sensor outputs of these current sensor 1a and load measurement sensors 3a and 12a are input to the system control device 7.
The system control device 7 controls the fuel cell 1, the inverter 2, and the system interconnection breaker 4.

図２は、燃料電池１の概略構成を示すブロック図である。
天然ガスやＬＰＧ等といった原燃料は、原燃料供給系２１を経て燃料反応器２２に供給される。この燃料反応器２２は、脱硫器２２ａ、ＣＯ変成器２２ｂ及び熱交換機２２ｃが一体に組み込まれて形成され、燃料反応器２２に供給された原燃料は、熱交換器２２ｃで加熱された後、脱硫器２２ａに供給される。
脱硫器２２ａは、天然ガスやＬＰＧ等といった炭化水素系の原燃料に含まれる硫黄分を除去する脱硫触媒が充填され、脱硫器２２ａで脱硫された原燃料は、エゼクタ２３に送られる。
エゼクタ２３は、脱硫器２２ａからの原燃料と、水蒸気供給系２３ａを経て導入される水蒸気分離器２４で分離された水蒸気とを混合して改質器２５に供給する。 FIG. 2 is a block diagram showing a schematic configuration of the fuel cell 1.
Raw fuel such as natural gas or LPG is supplied to the fuel reactor 22 via the raw fuel supply system 21. The fuel reactor 22 is formed by integrating a desulfurizer 22a, a CO converter 22b, and a heat exchanger 22c, and the raw fuel supplied to the fuel reactor 22 is heated by the heat exchanger 22c, It is supplied to the desulfurizer 22a.
The desulfurizer 22 a is filled with a desulfurization catalyst for removing sulfur contained in hydrocarbon-based raw fuel such as natural gas and LPG, and the raw fuel desulfurized by the desulfurizer 22 a is sent to the ejector 23.
The ejector 23 mixes the raw fuel from the desulfurizer 22a and the steam separated by the steam separator 24 introduced through the steam supply system 23a and supplies the mixed fuel to the reformer 25.

改質器２５には、水蒸気と混合された原燃料がエゼクタ２３から導入されると共に、燃焼空気供給用ブロア２６ａを備えた燃焼空気供給系２６を通して燃焼空気が導入され、さらに、燃料電池本体２７から排出される未反応水素を含む燃料オフガスがオフガス供給系２８を経て導入される。そして、改質器２５において、水蒸気が付加された原燃料がバーナ２５ａによる燃焼により水蒸気改質されて、水素に富む水素リッチガスが生成される。   Raw fuel mixed with water vapor is introduced into the reformer 25 from the ejector 23, and combustion air is introduced through a combustion air supply system 26 including a combustion air supply blower 26a. A fuel off-gas containing unreacted hydrogen discharged from the fuel is introduced through an off-gas supply system 28. Then, in the reformer 25, the raw fuel to which the steam is added is steam reformed by the combustion by the burner 25a, and a hydrogen rich gas rich in hydrogen is generated.

改質器２５で生成された水素リッチガスはＣＯ変成器２２ｂに送られ、含まれる触媒被毒物質であるＣＯがＣＯ2へ変成された後、燃焼ガスとして、改質ガス供給系２９を経て燃料電池本体２７の燃料極２７ａへと送られる。また、改質器２５から出た燃焼排ガスは、燃焼排ガス系３０を通して水回収用凝縮器３１に送られる。
一方、燃料電池本体２７の空気極２７ｂには、反応空気ブロア３２ａを備えた反応空気供給系３２を通して反応用の空気が送られ、電池反応後の空気は、空気排出系３３を通して水回収用凝縮器３１に送られる。 The hydrogen-rich gas generated in the reformer 25 is sent to the CO converter 22b, and the catalyst poisoning substance CO contained therein is converted into CO 2 , and then burned as fuel through the reformed gas supply system 29. It is sent to the fuel electrode 27a of the battery body 27. Further, the flue gas discharged from the reformer 25 is sent to the water recovery condenser 31 through the flue gas system 30.
On the other hand, reaction air is sent to the air electrode 27 b of the fuel cell body 27 through a reaction air supply system 32 equipped with a reaction air blower 32 a, and the air after the cell reaction is condensed through the air discharge system 33 for water recovery. Sent to the container 31.

また、燃料電池本体２７には、冷却板２７ｃが組み込まれている。この冷却板２７ｃの内部には、水蒸気分離器２４に貯留された、電気伝導度が低く且つシリカ等の鉱物系異物の少ない純水が冷却水として供給される。この純水は、燃料電池冷却水循環ポンプ３４ａを備えた冷却水循環系３４により水蒸気分離器２４から循環供給されると共に、純水の一部は、燃料電池用冷却水の廃熱回収用の熱交換器３４ｂを介して循環供給され、これによって、燃料電池本体２７の発電に伴う発熱を除去し、燃料電池本体２７の温度を所定の運転温度に維持している。   A cooling plate 27 c is incorporated in the fuel cell body 27. Inside the cooling plate 27c, pure water stored in the water vapor separator 24 and having a low electrical conductivity and a small amount of mineral foreign matters such as silica is supplied as cooling water. The pure water is circulated and supplied from the water vapor separator 24 by the cooling water circulation system 34 provided with the fuel cell cooling water circulation pump 34a, and a part of the pure water is heat exchange for recovering waste heat of the fuel cell cooling water. Thus, the heat generated by the power generation of the fuel cell main body 27 is removed, and the temperature of the fuel cell main body 27 is maintained at a predetermined operating temperature.

冷却水循環系３４により燃料電池本体２７に循環供給され、燃料電池本体２７での発電による生成熱を除去して冷却し、その熱を得て高温になった加圧水、或いは水と水蒸気とからなる気液二層流の冷却水は、冷却水加熱器３５を経て水蒸気分離器２４の気相部へと還流される。
冷却水加熱器３５は、起動時及び水蒸気分離器２４の圧力変動時の補償用として設置されているものであって、電気ヒータを組み込んで構成される。この電気ヒータの負荷量は調整可能に構成され、図１に示すシステム制御装置７により可変制御される。 The cooling water circulation system 34 circulates and supplies the fuel cell main body 27 to remove the generated heat generated by the power generation in the fuel cell main body 27 and cools it. The two-layered cooling water is refluxed to the vapor phase portion of the water vapor separator 24 via the cooling water heater 35.
The cooling water heater 35 is installed for compensation at the time of startup and when the pressure of the water vapor separator 24 fluctuates, and is configured by incorporating an electric heater. The load amount of the electric heater is configured to be adjustable, and is variably controlled by the system control device 7 shown in FIG.

水回収用凝縮器３１には燃焼排ガス系３０を通して改質器２５からの燃焼排ガスが導入されると共に、空気排出系３３を通して燃料電池本体２７の空気極２７ｂからの電池反応後の空気排出ガスが導入され、高温冷却水往ライン４１を通して導入される空冷式冷却器４２で冷却された冷却水により、燃焼排ガス及び空気排出ガス中の回収水を冷却する。   Combustion exhaust gas from the reformer 25 is introduced into the water recovery condenser 31 through the combustion exhaust gas system 30, and air exhaust gas after the cell reaction from the air electrode 27 b of the fuel cell main body 27 passes through the air exhaust system 33. The recovered water in the combustion exhaust gas and the air exhaust gas is cooled by the cooling water introduced and cooled by the air-cooled cooler 42 introduced through the high-temperature cooling water forward line 41.

水回収用凝縮器３１で回収された生成水のうち、一部は、回収水循環ポンプ４３ａ及び外部冷却器循環ポンプ４３ｂを備える排熱低温水往ライン４３を通して空冷式冷却器４２に導入される。排熱低温水往ライン４３の、回収水循環ポンプ４３ａと外部冷却器循環ポンプ４３ｂとの間には三方調節弁４３ｃが設けられ、排熱低温水往ライン４３を循環する、水回収用凝縮器３１で回収された生成水の一部は冷却媒体循環系４４に排出される。この冷却媒体循環系４４に排出された水回収用凝縮器３１からの生成水は、冷却媒体として燃料電池用冷却水の廃熱回収用熱交換器３４ｂに供給された後、排熱中温水熱交換器４４ａに供給され、ここで熱交換された後、一部は排熱低温水往ライン４３に戻される。   Part of the generated water recovered by the water recovery condenser 31 is introduced into the air-cooled cooler 42 through the exhaust heat low-temperature water feed line 43 including the recovered water circulation pump 43a and the external cooler circulation pump 43b. A three-way control valve 43 c is provided between the recovered water circulation pump 43 a and the external cooler circulation pump 43 b in the exhaust heat low temperature water feed line 43, and circulates in the exhaust heat low temperature water feed line 43. A part of the generated water recovered in step (1) is discharged to the cooling medium circulation system 44. The generated water from the water recovery condenser 31 discharged to the cooling medium circulation system 44 is supplied as a cooling medium to the waste heat recovery heat exchanger 34b for the fuel cell cooling water, and then the hot water during the heat exchange during exhaust heat. After the heat is exchanged here, a part is returned to the exhaust heat low temperature water feed line 43.

また、排熱低温水往ライン４３の、外部冷却器循環ポンプ４３ｂと空冷式冷却器４２との間には三方調節弁４３ｄが設けられ、排熱低温水往ライン４３を流れる生成水の一部は、高温冷却水往ライン４１に排出される。
水回収用凝縮器３１で生成された生成水は、さらに補給水ポンプ４６ａを備えた生成水回収ライン４６を介して燃料電池高温水熱変換器４７に供給された後、イオン交換式水処理装置４８に導入される。そして、このイオン交換式水処理装置４８で生成された純水が給水ポンプ４９により、燃料電池冷却水循環ポンプ３４ａの吸入側に吐出され、これによって、水蒸気分離器２４の純水の補給が行われる。 Further, a three-way control valve 43 d is provided between the external cooler circulation pump 43 b and the air-cooled cooler 42 in the exhaust heat low temperature water feed line 43, and a part of the generated water flowing through the exhaust heat low temperature water feed line 43. Is discharged to the high-temperature cooling water feed line 41.
The generated water generated by the water recovery condenser 31 is further supplied to the fuel cell high-temperature hydrothermal converter 47 via the generated water recovery line 46 provided with the makeup water pump 46a, and then the ion exchange type water treatment device. 48. The pure water generated by the ion exchange type water treatment device 48 is discharged to the suction side of the fuel cell cooling water circulation pump 34a by the feed water pump 49, whereby the pure water of the water vapor separator 24 is replenished. .

燃料電池高温水熱交換機４７には、冷却媒体として、高温冷却水往ライン４１を流れる冷却水が冷却媒体循環系４７ａにより循環供給される。
そして、水蒸気分離器２４には、水蒸気分離器２４の圧力を検出するための圧力センサ２４ａが設けられている。また、冷却水加熱器３５には、その負荷量を検出するための負荷計測センサ３５ａが設けられている。これら圧力センサ２４ａ及び負荷計測センサ３５ａのセンサ出力は、図１に示すシステム制御装置７に入力される。 In the fuel cell high-temperature water heat exchanger 47, the cooling water flowing through the high-temperature cooling water forward line 41 is circulated and supplied as a cooling medium by the cooling medium circulation system 47a.
The steam separator 24 is provided with a pressure sensor 24 a for detecting the pressure of the steam separator 24. The cooling water heater 35 is provided with a load measuring sensor 35a for detecting the load amount. The sensor outputs of the pressure sensor 24a and the load measurement sensor 35a are input to the system controller 7 shown in FIG.

システム制御装置７は、図示しない各種センサのセンサ出力に基づいて、燃料電池１、インバータ２、系統連系用遮断器４を駆動制御し、連系運転時には、燃料電池１と系統電源１１とで連系して顧客負荷１２への給電を行い、顧客負荷１２への供給電力が不足するときには系統電源１１からの電力を顧客負荷１２に供給して不足分を補い、顧客負荷１２への供給電力に余剰分が生じる場合にはこれを系統電源１１に供給する。   The system control device 7 drives and controls the fuel cell 1, the inverter 2, and the grid connection circuit breaker 4 based on sensor outputs of various sensors (not shown). Power is supplied to the customer load 12 through interconnection, and when the supply power to the customer load 12 is insufficient, the power from the system power supply 11 is supplied to the customer load 12 to compensate for the shortage, and the supply power to the customer load 12 If there is a surplus in the power supply, this is supplied to the system power supply 11.

一方、系統電源１１側に停電等異常が生じた場合には、系統連系用遮断器４を開状態に切り替え、燃料電池１及び顧客負荷１２を系統電源１１から切り離して自立運転に切り替え、燃料電池１の発電出力のみを用いて顧客負荷１２への電力供給を行う。
また、システム制御装置７は、自立運転中は、負荷計測センサ３ａ及び１２ａのセンサ出力に基づき補機負荷３の負荷量と顧客負荷１２の負荷量との和が所定値となるように、冷却水加熱器３５を構成する電気ヒータの負荷量を調整する負荷量一定制御を行う。この負荷量一定制御により、顧客負荷１２の負荷変動に応じて冷却水加熱器３５の負荷を変動させることにより、燃料電池１の発電出力を変化させることなく、燃料電池１の発電出力と、燃料電池１の電力負荷である顧客負荷１２及び補機負荷３とのバランスを保ち、顧客負荷１２の負荷変動に伴って、燃料電池１の周辺機器の応答遅れのために燃料電池１に燃料や空気の供給不足が生じることなく、燃料電池本体２７の電池特性の劣化を防止する。 On the other hand, when an abnormality such as a power failure occurs on the system power supply 11 side, the system interconnection circuit breaker 4 is switched to the open state, the fuel cell 1 and the customer load 12 are disconnected from the system power supply 11 and switched to the independent operation, Electric power is supplied to the customer load 12 using only the power generation output of the battery 1.
Further, the system control device 7 performs cooling so that the sum of the load amount of the auxiliary load 3 and the load amount of the customer load 12 becomes a predetermined value based on the sensor outputs of the load measurement sensors 3a and 12a during the self-sustained operation. A load amount constant control for adjusting the load amount of the electric heater constituting the water heater 35 is performed. With this constant load amount control, the power generation output of the fuel cell 1 and the fuel can be changed without changing the power generation output of the fuel cell 1 by changing the load of the cooling water heater 35 according to the load fluctuation of the customer load 12. The balance between the customer load 12 and the auxiliary machine load 3 which are power loads of the battery 1 is maintained, and fuel or air is supplied to the fuel cell 1 due to a delay in response of peripheral devices of the fuel cell 1 due to the load fluctuation of the customer load 12. The deterioration of the battery characteristics of the fuel cell main body 27 is prevented without causing a shortage of supply.

さらに、システム制御装置７は、自立運転中、電流センサ１ａ及び圧力センサ２４ａのセンサ出力を監視し、電流センサ１ａで検出される燃料電池１の発電電流が予め設定した許容範囲内に収まるように、冷却水加熱器３５を構成する電気ヒータの負荷量を調整する発電出力制御を実行する。また、これと共に、圧力センサ２４ａで検出される水蒸気分離器２４の圧力が、予め設定した燃料電池１での安定した電力発電が可能な許容範囲内に収まるように、冷却水加熱器３５を構成する電気ヒータの負荷量を調整する圧力制御を実行する。   Further, the system control device 7 monitors the sensor outputs of the current sensor 1a and the pressure sensor 24a during the self-sustaining operation so that the generated current of the fuel cell 1 detected by the current sensor 1a is within a preset allowable range. Then, the power generation output control for adjusting the load amount of the electric heater constituting the cooling water heater 35 is executed. At the same time, the cooling water heater 35 is configured so that the pressure of the water vapor separator 24 detected by the pressure sensor 24a falls within an allowable range in which stable power generation is possible in the fuel cell 1 set in advance. The pressure control for adjusting the load amount of the electric heater is executed.

ここで、燃料電池１による発電では、主燃料とする都市ガスの流量によって取り出し得る電流量に制約があるため、発電電流をある程度の大きさ以下に制限する必要がある。また、燃料電池１の燃料電池本体２７を腐食等から保護するためには発電電圧をある程度の大きさ以下に制限する必要がある。
すなわち、図３の特性図に示すように、燃料電池１の発電電流及び発電電圧がそれぞれの上限値を共に下回る範囲に収まるように、燃料電池１の発電出力を制御する必要がある。なお、図３において、横軸は発電電流、縦軸は発電電圧であって、斜線で示す領域は、燃料電池１の発電電流及び発電電圧の少なくとも何れか一方が、それぞれの上限値を上回る領域、すなわち非安定領域を表す。図３において、発電電流及び発電電圧がそれぞれの上限値以下となる領域、すなわち図３において斜線領域に囲まれた領域が安定領域となり、燃料電池１の発電出力が安定領域に収まるように燃料電池１を制御する必要がある。 Here, in the power generation by the fuel cell 1, since there is a restriction on the amount of current that can be extracted depending on the flow rate of the city gas as the main fuel, it is necessary to limit the generated current to a certain level or less. Further, in order to protect the fuel cell body 27 of the fuel cell 1 from corrosion or the like, it is necessary to limit the generated voltage to a certain level or less.
That is, as shown in the characteristic diagram of FIG. 3, it is necessary to control the power generation output of the fuel cell 1 so that the power generation current and the power generation voltage of the fuel cell 1 fall within the ranges below both upper limit values. In FIG. 3, the horizontal axis is the generated current, the vertical axis is the generated voltage, and the hatched area is the area where at least one of the generated current and generated voltage of the fuel cell 1 exceeds the respective upper limit value. That is, it represents an unstable region. In FIG. 3, the region where the generated current and the generated voltage are less than the respective upper limit values, that is, the region surrounded by the hatched region in FIG. 3, is the stable region, and the fuel cell 1 has the power generation output within the stable region. 1 needs to be controlled.

このため、電流センサ１ａのセンサ出力を監視し、センサ出力が発電電流の上限値を超えるときには冷却水加熱器３５の電気ヒータの負荷量を減少させて消費電流の削減を図ることで発電電流の減少を図る。また、発電電圧の監視は、電流センサ１ａのセンサ出力を用いて行い、発電電圧が発電電圧の上限値を超えるとき、すなわち、電流センサ１ａのセンサ出力が発電電圧の上限値相当の発電電流値を下回るときには、冷却水加熱器３５の電気ヒータの負荷量を増大させて消費電流の増大を図ることで発電電圧の減少を図る。   For this reason, the sensor output of the current sensor 1a is monitored, and when the sensor output exceeds the upper limit value of the generated current, the load of the electric heater of the cooling water heater 35 is decreased to reduce the consumed current. Reduce. The generated voltage is monitored using the sensor output of the current sensor 1a. When the generated voltage exceeds the upper limit value of the generated voltage, that is, the generated current value corresponding to the upper limit value of the generated voltage. When the value is lower than the value, the load of the electric heater of the cooling water heater 35 is increased to increase the consumption current, thereby reducing the generated voltage.

次に、本発明の動作を、図４及び図５のフローチャートに基づいて説明する。なお、図４は、システム制御装置７で実行される、負荷量一定制御処理の処理手順を示したものであり、図５は、システム制御装置７で実行される、発電出力及び圧力制御処理の処理手順を示したものである。これら負荷量一定制御処理、また、発電出力及び圧力制御処理は、予め設定した定周期で実行される。   Next, the operation of the present invention will be described based on the flowcharts of FIGS. FIG. 4 shows the processing procedure of the constant load amount control process executed by the system control device 7, and FIG. 5 shows the power generation output and pressure control processing executed by the system control device 7. The processing procedure is shown. These constant load amount control processing, as well as the power generation output and pressure control processing, are executed at a preset constant cycle.

システム制御装置７では、自立運転中は、図４に示す負荷量一定制御を行い、まず、負荷計測センサ３ａ及び１２ａのセンサ出力を読み込む（ステップＳ１）。次いで、補機負荷３及び顧客負荷１２の負荷量の和が予め設定した所定値であるかどうかを判定し（ステップＳ２）、所定値であれば負荷量の和は一定に維持されているとしてそのまま処理を終了する。一方、ステップＳ２で、補機負荷３及び顧客負荷１２の負荷量の和が所定値でなければステップＳ３に移行し、これらの和が所定値となるように冷却水加熱器３５の電気ヒータの負荷量を制御する。これにより、顧客負荷１２の負荷変動に対し、燃料電池１の応答遅れによる影響を受けることなく、顧客負荷１２への電力供給の負荷追従特性が確保されることになる。   In the self-sustained operation, the system controller 7 performs constant load amount control shown in FIG. 4 and first reads the sensor outputs of the load measurement sensors 3a and 12a (step S1). Next, it is determined whether or not the sum of the load amounts of the auxiliary machine load 3 and the customer load 12 is a predetermined value set in advance (step S2), and if it is a predetermined value, the sum of the load amounts is maintained constant. The process is terminated as it is. On the other hand, if the sum of the load amounts of the auxiliary machine load 3 and the customer load 12 is not a predetermined value in step S2, the process proceeds to step S3, and the electric heater of the cooling water heater 35 is set so that these sums become a predetermined value. Control the load. Thereby, the load follow-up characteristic of the power supply to the customer load 12 is ensured without being affected by the delay in response of the fuel cell 1 to the load fluctuation of the customer load 12.

システム制御装置７では、この負荷量一定制御と共に、図５に示す、発電出力及び圧力制御処理を実行する。まず、ステップＳ１１で電流センサ１ａのセンサ出力である、燃料電池１の出力電流が、予め設定した上限値Ｉmaxを上回っているか否かを判断する。この上限値Ｉmaxは、例えば、燃料電池１本体に影響を及ぼすことなく安定した発電出力を得ることの可能な発電電流の最大値である最大許容値よりも１％程度小さな値に設定される。   The system control device 7 executes the power generation output and pressure control processing shown in FIG. 5 together with this constant load amount control. First, in step S11, it is determined whether or not the output current of the fuel cell 1, which is the sensor output of the current sensor 1a, exceeds a preset upper limit value Imax. This upper limit value Imax is set, for example, to a value about 1% smaller than the maximum allowable value that is the maximum value of the generated current that can obtain a stable generated output without affecting the main body of the fuel cell 1.

そして、電流センサ１ａのセンサ出力が上限値Ｉmaxよりも大きいときには、ステップＳ１１からステップＳ１２に移行し、冷却水加熱器３５の電気ヒータの負荷量を所定量（例えば、５ｋＷ程度）だけ減少させる。つまり、負荷量一定制御により設定された電気ヒータの負荷量をさらに所定量だけ減少させる。これにより、冷却水加熱器３５の電気ヒータの負荷量が低めに設定され、電気ヒータの消費電流がその分減少するため、結果的に燃料電池１の発電電流が低下する。このため、燃料電池１の発電出力が図３の安定領域に収まることになって、燃料電池１を保護することができる。   When the sensor output of the current sensor 1a is larger than the upper limit value Imax, the process proceeds from step S11 to step S12, and the load amount of the electric heater of the cooling water heater 35 is decreased by a predetermined amount (for example, about 5 kW). That is, the load amount of the electric heater set by the constant load amount control is further reduced by a predetermined amount. Thereby, the load amount of the electric heater of the cooling water heater 35 is set to be low, and the current consumption of the electric heater is reduced accordingly, so that the generated current of the fuel cell 1 is lowered as a result. For this reason, the power generation output of the fuel cell 1 falls within the stable region of FIG. 3, and the fuel cell 1 can be protected.

一方、電流センサ１ａのセンサ出力が上限値Ｉmax以下であるときには、ステップＳ１１からステップＳ１３に移行し、次に電流センサ１ａのセンサ出力が、発電電流の下限値Ｉminを下回るか否かを判定する。この発電電流の下限値Ｉminは、燃料電池１の発電電圧の最大許容値に応じて設定される。この最大許容値は、例えば、燃料電池１に影響を及ぼすことなく安定した発電出力を得ることの可能な発電電圧の最大値である。下限値Ｉminは、発電電圧の最大許容値を満足するときの発電電流の最小値を最小許容値としたとき、この最小許容値よりも１％程度大きな値に設定される。   On the other hand, when the sensor output of the current sensor 1a is equal to or lower than the upper limit value Imax, the process proceeds from step S11 to step S13, and then it is determined whether or not the sensor output of the current sensor 1a is lower than the lower limit value Imin of the generated current. . The lower limit value Imin of the generated current is set according to the maximum allowable value of the generated voltage of the fuel cell 1. This maximum allowable value is, for example, the maximum value of the generated voltage that can obtain a stable generated output without affecting the fuel cell 1. The lower limit value Imin is set to a value about 1% larger than the minimum allowable value when the minimum value of the generated current when the maximum allowable value of the generated voltage is satisfied is set as the minimum allowable value.

そして、電流センサ１ａのセンサ出力が下限値Ｉminを下回るとき、すなわち、発電電圧が最大許容値を超えるときには、ステップＳ１３からステップＳ１４に移行し、冷却水加熱器３５の電気ヒータの負荷量を所定量（例えば、５ｋＷ程度）だけ増加させる。つまり、負荷量一定制御により設定された電気ヒータの負荷量をさらに所定量だけ増加させる。これにより、冷却水加熱器３５の電気ヒータの負荷量が高めに設定され、電気ヒータの消費電流がその分増加するため、結果的に燃料電池１の発電電圧が低下する。このため、燃料電池１の発電出力が図３の安定領域に収まることになって、燃料電池１を保護することができる。   When the sensor output of the current sensor 1a falls below the lower limit value Imin, that is, when the generated voltage exceeds the maximum allowable value, the process proceeds from step S13 to step S14, and the load amount of the electric heater of the cooling water heater 35 is determined. Increase by a fixed amount (for example, about 5 kW). That is, the load amount of the electric heater set by the constant load amount control is further increased by a predetermined amount. Thereby, the load amount of the electric heater of the cooling water heater 35 is set to be high, and the current consumption of the electric heater is increased accordingly, and as a result, the generated voltage of the fuel cell 1 is lowered. For this reason, the power generation output of the fuel cell 1 falls within the stable region of FIG. 3, and the fuel cell 1 can be protected.

また、電流センサ１ａのセンサ出力が、上限値Ｉmax以下であり且つ下限値Ｉmin以上であるときにはステップＳ１５に移行し、次に、圧力センサ２４ａのセンサ出力である、水蒸気分離器２４の圧力が、最大圧力Ｐmaxを上回るかどうかを判定する。この最大圧力Ｐmaxは、燃料電池１において安定した電力発電を行うことの可能な、水蒸気分離器２４の圧力の最大値である最大許容値に応じて設定され、例えば、最大許容値よりも１％程度小さな値に設定される。   When the sensor output of the current sensor 1a is equal to or lower than the upper limit value Imax and equal to or higher than the lower limit value Imin, the process proceeds to step S15. Next, the pressure of the water vapor separator 24, which is the sensor output of the pressure sensor 24a, is It is determined whether the maximum pressure Pmax is exceeded. This maximum pressure Pmax is set according to the maximum allowable value that is the maximum value of the pressure of the water vapor separator 24 that can perform stable power generation in the fuel cell 1, and is, for example, 1% higher than the maximum allowable value. It is set to a small value.

そして、圧力センサ２４ａのセンサ出力が最大圧力Ｐmaxを上回るときには、ステップＳ１５からステップＳ１２に移行し、冷却水加熱器３５の電気ヒータの負荷量を所定量減少させる。これにより、水蒸気分離器２４の圧力が低下するため、エゼクタ２３への高圧の水蒸気の供給量を安定させることができ、燃料電池１の発電出力特性の変動を抑制することができる。   When the sensor output of the pressure sensor 24a exceeds the maximum pressure Pmax, the process proceeds from step S15 to step S12, and the load amount of the electric heater of the cooling water heater 35 is decreased by a predetermined amount. Thereby, since the pressure of the water vapor separator 24 decreases, the amount of high-pressure water vapor supplied to the ejector 23 can be stabilized, and fluctuations in the power generation output characteristics of the fuel cell 1 can be suppressed.

一方、圧力センサ２４ａのセンサ出力が最大圧力Ｐmax以下であるときには、ステップＳ１５からステップＳ１６に移行し、圧力センサ２４ａのセンサ出力が最小圧力Ｐminを下回るかどうかを判定する。この最小圧力Ｐminは、水蒸気分離器２４の圧力が、燃料電池１において安定した電力発電を行うことの可能な圧力の最小値である最小許容値に応じて設定され、例えば最小許容値よりも１％程度大きな値に設定される。   On the other hand, when the sensor output of the pressure sensor 24a is equal to or lower than the maximum pressure Pmax, the process proceeds from step S15 to step S16, and it is determined whether or not the sensor output of the pressure sensor 24a falls below the minimum pressure Pmin. The minimum pressure Pmin is set in accordance with a minimum allowable value that is a minimum value of the pressure at which the steam separator 24 can stably generate power in the fuel cell 1, and is, for example, 1 less than the minimum allowable value. It is set to a large value by about%.

そして、圧力センサ２４ａのセンサ出力が最小圧力Ｐminを下回るときには、ステップＳ１６からステップＳ１４に移行し、冷却水加熱器３５の電気ヒータの負荷量を所定量増加させる。これにより、水蒸気分離器２４の圧力が増加するため、エゼクタ２３への高圧の水蒸気の供給量を安定させることができ、燃料電池１の発電出力特性の変動を抑制することができる。   When the sensor output of the pressure sensor 24a falls below the minimum pressure Pmin, the process proceeds from step S16 to step S14, and the load amount of the electric heater of the cooling water heater 35 is increased by a predetermined amount. Thereby, since the pressure of the water vapor separator 24 increases, the amount of high-pressure water vapor supplied to the ejector 23 can be stabilized, and fluctuations in the power generation output characteristics of the fuel cell 1 can be suppressed.

さらに、電流センサ１ａのセンサ出力が、上限値Ｉmax以下且つ下限値Ｉmin以上であり、圧力センサ２４ａのセンサ出力が、最大圧力Ｐmax以下且つ最小圧力Ｐmin以上であるときには、冷却水加熱器３５の電気ヒータの負荷量の調整は行わない。このため、電気ヒータの負荷量は、負荷量一定制御に基づき設定された値となって、顧客負荷１２の負荷変動に対し、燃料電池１の応答遅れによる影響を受けることなく、顧客負荷１２への電力供給の負荷追従性を確保することができる。   Further, when the sensor output of the current sensor 1a is not more than the upper limit value Imax and not less than the lower limit value Imin, and the sensor output of the pressure sensor 24a is not more than the maximum pressure Pmax and not less than the minimum pressure Pmin, the electric power of the cooling water heater 35 is The heater load is not adjusted. For this reason, the load amount of the electric heater becomes a value set based on the constant load amount control, and is not affected by the response delay of the fuel cell 1 with respect to the load fluctuation of the customer load 12, so It is possible to ensure load followability of the power supply.

以上の処理が、システム制御装置７により所定周期で実行されるため、負荷量一定制御が行われることにより、燃料電池１の発電出力が図３の安定領域を超えたときには、これを抑制するように冷却水加熱器３５の負荷量の制御が行われ、燃料電池１の発電出力は安定領域の範囲内で制御されることになる。このため、燃料電池１の発電電流や発電電圧が許容値を超えることによって、燃料電池１に悪影響を与えることを回避し、燃料電池１を保護することができる。   Since the above processing is executed in a predetermined cycle by the system control device 7, when the load generation constant control is performed, when the power generation output of the fuel cell 1 exceeds the stable region of FIG. Then, the load amount of the cooling water heater 35 is controlled, and the power generation output of the fuel cell 1 is controlled within the stable region. For this reason, it is possible to prevent the fuel cell 1 from being adversely affected and to protect the fuel cell 1 when the generated current or generated voltage of the fuel cell 1 exceeds the allowable value.

また、負荷量一定制御により冷却水加熱器３５の負荷量が調整されることに伴って、水蒸気分離器２４に圧力変動が生じたときには、水蒸気分離器２４の圧力が許容範囲内に収まるように冷却水加熱器３５の負荷量を制御するため、負荷量一定制御により負荷追従性を確保しつつ、エゼクタ２３への安定した水蒸気供給を行うことにより、燃料電池１の発電出力特性の変化を抑制し、安定した電力発電を継続することができる。   In addition, when the load variation of the cooling water heater 35 is adjusted by the constant load amount control, and the pressure fluctuation occurs in the water vapor separator 24, the pressure of the water vapor separator 24 falls within the allowable range. In order to control the load amount of the cooling water heater 35, the change of the power generation output characteristics of the fuel cell 1 is suppressed by supplying stable water vapor to the ejector 23 while ensuring load followability by constant load amount control. In addition, stable power generation can be continued.

このように、負荷量一定制御を行うことにより、冷却水加熱器３５の負荷量が変動し、これに伴って、燃料電池１の発電出力特性が変化したり、水蒸気分離器２４に圧力変動が生じたりした場合であっても、これらを抑制するように、冷却水加熱器３５の負荷量を調整しているから、燃料電池１の発電電流や発電電圧が許容値を超えることにより燃料電池１に腐食が生じる等といったことを回避し燃料電池１の保護を図ることができると共に、水蒸気分離器２４の圧力の変動に伴って燃料電池１の出力特性が変化することを回避することができ、安定した電力発電を継続することができる。   As described above, by performing the constant load amount control, the load amount of the cooling water heater 35 fluctuates, and accordingly, the power generation output characteristics of the fuel cell 1 change, or the pressure fluctuation in the water vapor separator 24 changes. Even if it occurs, since the load amount of the cooling water heater 35 is adjusted so as to suppress these, the power generation current and power generation voltage of the fuel cell 1 exceed the allowable values. It is possible to protect the fuel cell 1 by avoiding the occurrence of corrosion, etc., and to avoid changing the output characteristics of the fuel cell 1 due to fluctuations in the pressure of the water vapor separator 24, Stable power generation can be continued.

また、このとき、水蒸気分離器２４の圧力の変動による影響が燃料電池１の出力特性の変化として現れるまでに応答遅れが生じる水蒸気分離器２４の圧力の安定性よりも、燃料電池１の出力特性の安定性確保を優先して冷却水加熱器３５の負荷量を調整しており、燃料電池１の出力特性の安定性確保を優先して負荷量を制御すると共に、燃料電池１に出力特性の変動をもたらすような水蒸気分離器２４の圧力変動を抑制するようにしているから、燃料電池１の保護を効率よく行うことができる。   At this time, the output characteristic of the fuel cell 1 is more than the stability of the pressure of the water vapor separator 24 in which a response delay occurs until the influence of the fluctuation of the pressure of the water vapor separator 24 appears as a change in the output characteristic of the fuel cell 1. The load amount of the cooling water heater 35 is adjusted with priority given to ensuring the stability of the fuel cell 1, and the load amount is controlled with priority given to ensuring the stability of the output characteristics of the fuel cell 1. Since the pressure fluctuation of the water vapor separator 24 that causes fluctuations is suppressed, the fuel cell 1 can be protected efficiently.

なお、上記実施の形態においては、水蒸気分離器２４の圧力の安定性確保よりも、燃料電池１の出力特性の確保を優先して行う場合について説明したが、これに限るものではない。
例えば、水蒸気分離器２４の圧力安定性の確保を、燃料電池１の出力特性の確保よりも優先して行うようにしてもよく、要は、燃料電池発電システム１０の運用状況に応じて、燃料電池発電システム１０に与える影響を効率よく低減することができる方を優先して行うようにすればよい。 In the above-described embodiment, the case where priority is given to securing the output characteristics of the fuel cell 1 over securing the pressure stability of the water vapor separator 24 has been described, but the present invention is not limited to this.
For example, the pressure stability of the water vapor separator 24 may be secured in preference to the securing of the output characteristics of the fuel cell 1, and in short, depending on the operation status of the fuel cell power generation system 10, the fuel What is necessary is just to give priority to the direction which can reduce the influence which it has on the battery power generation system 10 efficiently.

また、上記実施の形態においては、燃料電池１の発電電流に基づいて、燃料電池１の出力特性を安定領域に収める場合について説明したが、これに限るものではない。
例えば、燃料電池１の発電電流に替えて、燃料電池１の発電電圧を検出しこれに基づいて、発電出力が安定領域に収まるように制御してもよい。また、発電電流及び発電電圧をそれぞれ検出しこれらがそれぞれの上限値を下回るように制御してもよく、要は、燃料電池１の発電出力が図３に示す安定領域に収まるように制御を行えば、発電電流及び発電電圧の何れに基づいて制御してもよい。 In the above embodiment, the case where the output characteristics of the fuel cell 1 are within the stable region based on the generated current of the fuel cell 1 has been described. However, the present invention is not limited to this.
For example, instead of the power generation current of the fuel cell 1, the power generation voltage of the fuel cell 1 may be detected, and based on this, control may be performed so that the power generation output falls within the stable region. Alternatively, the generated current and generated voltage may be detected and controlled so that they are below the respective upper limit values. In short, control is performed so that the generated output of the fuel cell 1 falls within the stable region shown in FIG. For example, the control may be performed based on either the generated current or the generated voltage.

また、上記実施の形態においては、水蒸気分離器２４の圧力に基づき、冷却水加熱器３５の負荷量を調整する場合について説明したが、これに限るものではない。
例えば、圧力センサ２４ａに替えて、例えば、水蒸気分離器２４の温度を検出する温度センサ、或いは、水蒸気分離器２４から出力される水蒸気流量を検出する水蒸気流量センサを設け、水蒸気分離器２４の圧力に替えて、温度センサで検出される水蒸気分離器２４の温度、或いは水蒸気流量センサで検出される水蒸気分離器２４から出力される水蒸気流量を、水蒸気分離器２４の圧力相当値として用い、この圧力相当値に基づき冷却水加熱器３５の負荷量を調整するようにしてもよい。 Moreover, in the said embodiment, although the case where the load amount of the cooling water heater 35 was adjusted based on the pressure of the water vapor separator 24 was demonstrated, it does not restrict to this.
For example, instead of the pressure sensor 24a, for example, a temperature sensor for detecting the temperature of the water vapor separator 24 or a water vapor flow rate sensor for detecting the water vapor flow rate output from the water vapor separator 24 is provided. Instead of this, the temperature of the water vapor separator 24 detected by the temperature sensor or the water vapor flow rate output from the water vapor separator 24 detected by the water vapor flow rate sensor is used as the pressure equivalent value of the water vapor separator 24 and this pressure is used. You may make it adjust the load amount of the cooling water heater 35 based on an equivalent value.

また、上記実施の形態においては、負荷量一定制御において、水蒸気分離器２４用の冷却水加熱器３５の電気ヒータの負荷量を調整することで顧客負荷１２と補器負荷３との負荷量の和が所定値となるように制御する場合について説明したが、これに限るものではない。例えば、冷却水加熱器３５の他に、負荷量調整用の電気ヒータを設け、冷却水加熱器３５の負荷量と共に負荷量調整用の電気ヒータの負荷量を調整することで、顧客負荷１２との負荷量の和を所定値に維持するように構成した場合であっても適用することができ、この場合には、負荷量の和を所定値に維持するために冷却水加熱器３５の負荷量を調整している場合にのみ、発電出力及び圧力制御処理を実行すればよい。   In the above embodiment, in the constant load amount control, the load amount of the customer load 12 and the auxiliary load 3 is adjusted by adjusting the load amount of the electric heater of the cooling water heater 35 for the steam separator 24. Although the case where control is performed so that the sum becomes a predetermined value has been described, the present invention is not limited to this. For example, in addition to the cooling water heater 35, an electric heater for adjusting the load amount is provided, and by adjusting the load amount of the electric heater for adjusting the load amount together with the load amount of the cooling water heater 35, the customer load 12 Even if it is configured to maintain the sum of the load amounts at a predetermined value, it can be applied. In this case, the load of the cooling water heater 35 is maintained in order to maintain the sum of the load amounts at a predetermined value. Only when the amount is adjusted, the power generation output and pressure control processing may be executed.

ここで、図５のステップＳ１１からステップＳ１２に移行して冷却水加熱器３５の電気ヒータの負荷量を調整する処理とステップＳ１３からステップＳ１４に移行して前記電気ヒータの負荷量を調整する処理とが、第１の負荷量調整ステップ及び第１の負荷量調整手段に対応している。また、図５のステップＳ１５からステップＳ１２に移行して前記電気ヒータの負荷量を調整する処理とステップＳ１６からステップＳ１４に移行して前記電気ヒータの負荷量を調整する処理とが、第２の負荷量調整ステップ及び第２の負荷量調整手段に対応している。   Here, the process which moves from step S11 of FIG. 5 to step S12 and adjusts the load amount of the electric heater of the cooling water heater 35 and the process which moves from step S13 to step S14 and adjusts the load amount of the electric heater. Corresponds to the first load amount adjusting step and the first load amount adjusting means. Further, a process for adjusting the load amount of the electric heater by moving from step S15 to step S12 in FIG. 5 and a process for adjusting the load amount of the electric heater by moving from step S16 to step S14 are the second steps. This corresponds to the load amount adjusting step and the second load amount adjusting means.

本発明を適用した燃料電池発電システムの一例を示す概略構成図である。It is a schematic structure figure showing an example of a fuel cell power generation system to which the present invention is applied. 図１の燃料電池の概略構成を示すブロック図である。It is a block diagram which shows schematic structure of the fuel cell of FIG. 燃料電池の出力特性を示す特性線図である。It is a characteristic diagram which shows the output characteristic of a fuel cell. 負荷量一定制御の処理手順の一例を示すフローチャートである。It is a flowchart which shows an example of the process sequence of load amount fixed control. 発電出力及び圧力制御処理の処理手順の一例を示すフローチャートである。It is a flowchart which shows an example of the process sequence of an electric power generation output and a pressure control process.

符号の説明Explanation of symbols

１ 燃料電池
１ａ 電流センサ
２ インバータ
３ 補機負荷
３ａ 負荷計測センサ
７ システム制御装置
１１ 系統電源
１２ 顧客負荷
１２ａ 負荷計測センサ
２４ 水蒸気分離器
２４ａ 圧力センサ
２５ 改質器
２７ 燃料電池本体
３５ 冷却水加熱器
３５ａ 負荷計測センサ DESCRIPTION OF SYMBOLS 1 Fuel cell 1a Current sensor 2 Inverter 3 Auxiliary load 3a Load measurement sensor 7 System controller 11 System power supply 12 Customer load 12a Load measurement sensor 24 Water vapor separator 24a Pressure sensor 25 Reformer 27 Fuel cell main body 35 Cooling water heater 35a Load measurement sensor

Claims (8)

系統電源とは独立に燃料電池から負荷に電力供給を行う自立運転中は、前記負荷と補機負荷との負荷合計が所定値となるように前記補機負荷の負荷量を調整し、且つ前記補機負荷として、燃料電池本体に供給される水素リッチガス生成用の水蒸気を出力する水蒸気分離器の温度調節用加熱器を用いる燃料電池発電システムの制御方法であって、
前記燃料電池の発電電力の出力特性が予め設定した出力特性の許容範囲に収まるように前記補機負荷の負荷量を調整する第１の負荷量調整ステップと、前記水蒸気分離器の圧力が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整する第２の負荷量調整ステップと、を備えることを特徴とする燃料電池発電システムの制御方法。 During independent operation in which power is supplied from the fuel cell to the load independently of the system power supply, the load amount of the auxiliary load is adjusted so that the total load of the load and the auxiliary load becomes a predetermined value, and A control method of a fuel cell power generation system using a temperature control heater of a steam separator that outputs steam for generating hydrogen-rich gas supplied to a fuel cell main body as an auxiliary load,
A first load amount adjusting step for adjusting a load amount of the auxiliary machine load so that an output characteristic of the generated power of the fuel cell falls within a preset allowable range of the output characteristic; and a pressure of the water vapor separator is preset. And a second load amount adjustment step of adjusting the load amount of the auxiliary load so as to fall within the allowable range. A control method for a fuel cell power generation system, comprising: 前記第１の負荷量調整ステップ及び前記第２の負荷量調整ステップのうちの何れかを他方よりも優先することを特徴とする請求項１記載の燃料電池発電システムの制御方法。   2. The method of controlling a fuel cell power generation system according to claim 1, wherein either one of the first load amount adjustment step and the second load amount adjustment step is prioritized over the other. 前記第１の負荷量調整ステップを前記第２の負荷量調整ステップよりも優先することを特徴とする請求項２記載の燃料電池発電システムの制御方法。   3. The control method for a fuel cell power generation system according to claim 2, wherein the first load amount adjustment step is prioritized over the second load amount adjustment step. 前記第１の負荷量調整ステップでは、前記燃料電池の発電電流が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整することを特徴とする請求項１から請求項３の何れか１項に記載の燃料電池発電システムの制御方法。   4. The load amount of the auxiliary load is adjusted in the first load amount adjusting step so that the generated current of the fuel cell is within a preset allowable range. 5. A control method for a fuel cell power generation system according to claim 1. 前記第１の負荷量調整ステップでは、前記燃料電池の発電電圧が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整することを特徴とする請求項１から請求項４の何れか１項に記載の燃料電池発電システムの制御方法。   5. The load amount of the auxiliary load is adjusted in the first load amount adjusting step so that the power generation voltage of the fuel cell is within a preset allowable range. A control method for a fuel cell power generation system according to claim 1. 前記第２の負荷量調整ステップでは、前記水蒸気分離器の水蒸気温度を検出し、前記水蒸気温度が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整することを特徴とする請求項１から請求項５の何れか１項に記載の燃料電池発電システムの制御方法。   In the second load amount adjustment step, the water vapor temperature of the water vapor separator is detected, and the load amount of the auxiliary load is adjusted so that the water vapor temperature falls within a preset allowable range. The control method for a fuel cell power generation system according to any one of claims 1 to 5. 前記第２の負荷量調整ステップでは、前記水蒸気分離器の水蒸気流量を検出し、前記水蒸気流量が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整することを特徴とする請求項１から請求項６の何れか１項に記載の燃料電池発電システムの制御方法。   In the second load amount adjustment step, the steam flow rate of the steam separator is detected, and the load amount of the auxiliary load is adjusted so that the steam flow rate falls within a preset allowable range. The method for controlling a fuel cell power generation system according to any one of claims 1 to 6. 系統電源とは独立に燃料電池から負荷に電力供給を行う自立運転中は、前記負荷と補機負荷との負荷合計が所定値となるように前記補機負荷の負荷量を調整し、且つ前記補機負荷として、燃料電池本体に供給される水素リッチガス生成用の水蒸気を出力する水蒸気分離器の温度調節用加熱器を用いる燃料電池発電システムであって、
前記燃料電池の発電電力の出力特性が予め設定した出力特性の許容範囲に収まるように前記補機負荷の負荷量を調整する第１の負荷量調整手段と、
前記水蒸気分離器の圧力が予め設定した許容範囲に収まるように前記補機負荷の負荷量を調整する第２の負荷量調整手段と、を備えたことを特徴とする燃料電池発電システム。 During independent operation in which power is supplied from the fuel cell to the load independently of the system power supply, the load amount of the auxiliary load is adjusted so that the total load of the load and the auxiliary load becomes a predetermined value, and A fuel cell power generation system using a temperature control heater of a steam separator that outputs steam for generating hydrogen-rich gas supplied to the fuel cell body as an auxiliary load,
First load amount adjusting means for adjusting the load amount of the auxiliary load so that the output characteristic of the generated power of the fuel cell falls within a preset allowable range of the output characteristic;
A fuel cell power generation system comprising: a second load amount adjusting means for adjusting a load amount of the auxiliary load so that the pressure of the water vapor separator falls within a preset allowable range.
JP2008128430A 2008-05-15 2008-05-15 Control method for fuel cell power generation system and fuel cell power generation system Expired - Fee Related JP5359022B2 (en)

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