JP2009070590A - Fuel cell power generation device and its operation method - Google Patents

Fuel cell power generation device and its operation method Download PDF

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JP2009070590A
JP2009070590A JP2007234908A JP2007234908A JP2009070590A JP 2009070590 A JP2009070590 A JP 2009070590A JP 2007234908 A JP2007234908 A JP 2007234908A JP 2007234908 A JP2007234908 A JP 2007234908A JP 2009070590 A JP2009070590 A JP 2009070590A
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fuel
inert gas
fuel cell
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Toru Kiyota
透 清田
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Fuji Electric 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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Abstract

<P>PROBLEM TO BE SOLVED: To provide an operation method in which a consumption of purging inert gas when it is stored during shutdown of power generation can be minimized and moreover a performance deterioration of a reforming catalyst can be avoided. <P>SOLUTION: A raw fuel supply shutdown valve 1 and a steam supply shutdown valve 10 and an exhaust valve 13 are shifted to a closed status, and inert gas purge valves 11, 12, 15 are shifted to an open status, and purging inert gas is sent from an air electrode 5b, then from a gas-liquid separation unit 8, then from a desulfurizer unit 2, a fuel reforming unit 3 and a CO converter 4, to a fuel electrode 5a, and purges all above units one by one, and is exhausted after being used for heating the fuel reforming unit 3 by a heater 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は燃料電池発電装置およびその運転方法に関わり、特に、発電運転を停止して保管する際の不活性ガスによるパージ方法に関する。   The present invention relates to a fuel cell power generator and an operation method thereof, and more particularly, to a purge method using an inert gas when the power generation operation is stopped and stored.

燃料電池発電装置は、複数の単位セルを積層して構成される燃料電池本体、原燃料を改質して燃料電池本体の燃料極に供給する高水素濃度の燃料ガスを得る燃料改質器、改質用水蒸気を取り出す気水分離器を備えた電池冷却水系等から構成される。従来の燃料電池発電装置では、発電運転を停止して保管状態とする際には、電池電圧の上昇を抑制し、燃料改質器の酸化を防止するために、特許文献１に開示されているように、空気極と燃料極、並びに燃料改質器を不活性ガスでパージして保持する方法が採られている。
図２は、原燃料として都市ガスを用いた従来のりん酸形燃料電池発電装置の発電運転を停止し、保管状態にある際の構成を模式的に示した図である。本図において、符号５は燃料電池本体であり、５ａはその燃料極、５ｂは空気極である。また、符号２，３，４は、それぞれ燃料改質系を構成する脱硫器、燃料改質器、ＣＯ変成器である。また、６は保温ヒーター、７は燃料改質器３の加熱用ヒーター、８は電池冷却水系の気水分離器である。図に見られるように、発電運転時には気水分離器８で分離された水蒸気が、脱硫器２で脱硫された都市ガスとともに燃料改質器３へと送られ、水蒸気改質される。改質ガスを燃料電池本体５の燃料極５ａに、反応空気を空気極５ｂに供給することによって発電が行われる。燃料電池発電装置の発電運転を停止して、保管状態とする際には、原燃料供給遮断弁１、および水蒸気供給遮断弁１０を閉止し、不活性ガスパージ弁１１を開放して、燃料極５ａおよびそれにつながる燃料改質器のパージを行うとともに、不活性ガスパージ弁１２を開放して、空気極５ｂのパージを行っている。 A fuel cell power generator includes a fuel cell main body configured by stacking a plurality of unit cells, a fuel reformer that reforms raw fuel and obtains a high hydrogen concentration fuel gas supplied to the fuel electrode of the fuel cell main body, It is composed of a battery cooling water system equipped with a steam separator for taking out reforming steam. In the conventional fuel cell power generation device, when the power generation operation is stopped and stored, the increase in the cell voltage is suppressed and the oxidation of the fuel reformer is prevented, which is disclosed in Patent Document 1. As described above, a method of purging and holding the air electrode, the fuel electrode, and the fuel reformer with an inert gas is employed.
FIG. 2 is a diagram schematically showing a configuration when a conventional phosphoric acid fuel cell power generation apparatus using city gas as raw fuel is stopped and in a storage state. In this figure, reference numeral 5 denotes a fuel cell body, 5a denotes a fuel electrode thereof, and 5b denotes an air electrode. Reference numerals 2, 3, and 4 denote a desulfurizer, a fuel reformer, and a CO converter that constitute the fuel reforming system, respectively. Further, 6 is a heat retaining heater, 7 is a heater for heating the fuel reformer 3, and 8 is an air / water separator of a battery cooling water system. As shown in the figure, during the power generation operation, the steam separated by the steam separator 8 is sent to the fuel reformer 3 together with the city gas desulfurized by the desulfurizer 2, and is steam reformed. Electric power is generated by supplying the reformed gas to the fuel electrode 5a of the fuel cell body 5 and the reaction air to the air electrode 5b. When the power generation operation of the fuel cell power generator is stopped and stored, the raw fuel supply cutoff valve 1 and the water vapor supply cutoff valve 10 are closed, the inert gas purge valve 11 is opened, and the fuel electrode 5a In addition to purging the fuel reformer connected thereto, the inert gas purge valve 12 is opened to purge the air electrode 5b.

また、燃料電池発電装置の発電運転停止、保管状態において、電池冷却水系の気水分離器８を密閉状態に保持すると、温度の低下に伴って負圧となり、損傷する危険性がある。このため、気水分離器８は負圧とならないように大気開放弁９を開いて大気開放状態にされる。したがって、気水分離器８の気相部は空気雰囲気に保持されることとなる。
例えば、 特開昭57―212774号公報、特開昭60―140672号公報、特開平４−26070号公報 など In addition, when the fuel cell power generation apparatus is stopped and stored, if the air / water separator 8 of the battery cooling water system is kept in a hermetically sealed state, there is a risk of damage due to negative pressure as the temperature decreases. For this reason, the air / water separator 8 is opened to the atmosphere by opening the atmosphere release valve 9 so as not to become negative pressure. Therefore, the gas phase portion of the steam separator 8 is maintained in an air atmosphere.
For example, JP-A-57-212774, JP-A-60-140672, JP-A-4-26070, etc.

上記のように、従来の燃料電池発電装置では、その発電運転を停止して保管状態に保持する際に、空気極と燃料極、並びに燃料改質器を不活性ガスでパージしており、これによって系が不活性ガス雰囲気に保たれ、電池電圧の上昇が抑制されるとともに、燃料改質器の改質触媒の酸化が防止されている。しかしながら、この構成の燃料電池発電装置では、上記のように、燃料極とそれに連通する燃料改質器をパージする系統と、空気極をパージする系統との二つの系統を用いてパージを行っているので、不活性ガスの消費量が多量になるという難点がある。
また、従来の燃料電池発電装置では、その発電運転を停止して保管状態に保持する際に、上記のように、気水分離器８の気相部は空気雰囲気に保持されるので、この燃料電池発電装置の再起動の際、気相部に滞留していた空気が水蒸気とともに燃料改質器へ送られ、燃料改質器の改質触媒が徐々に酸化して、改質性能が低下していくという問題点がある。
本発明は、このような技術の現状を顧慮してなされたもので、本発明の目的は、発電運転を停止して保管する際に使用されるパージ用の不活性ガスの消費量が少量に抑えられ、かつ、気水分離器への空気混入に起因する改質触媒の性能低下が回避されて、運転停止、保管が、低コストで、かつ性能低下を生じることなく安定に実施できる燃料電池発電装置およびその運転方法を提供することにある。 As described above, in the conventional fuel cell power generator, when the power generation operation is stopped and kept in the storage state, the air electrode, the fuel electrode, and the fuel reformer are purged with an inert gas. As a result, the system is maintained in an inert gas atmosphere, and an increase in battery voltage is suppressed, and oxidation of the reforming catalyst of the fuel reformer is prevented. However, in the fuel cell power generator of this configuration, as described above, purging is performed using two systems, the system that purges the fuel electrode and the fuel reformer that communicates with the fuel electrode, and the system that purges the air electrode. Therefore, there is a problem that the consumption of the inert gas is large.
Further, in the conventional fuel cell power generator, when the power generation operation is stopped and kept in the storage state, the gas phase portion of the steam separator 8 is maintained in the air atmosphere as described above. When the battery power generator is restarted, the air staying in the gas phase is sent to the fuel reformer along with water vapor, and the reforming catalyst of the fuel reformer is gradually oxidized, resulting in a decrease in reforming performance. There is a problem of going.
The present invention has been made in consideration of the current state of the art, and an object of the present invention is to reduce the consumption of the inert gas for purging used when the power generation operation is stopped and stored. A fuel cell that is suppressed and that can be stably operated at low cost and without performance degradation by preventing the performance degradation of the reforming catalyst due to air mixing into the steam separator. It is in providing a power generator and its operating method.

本発明においては、上記の目的を達成するために、
（１）単位セルを積層して構成される燃料電池本体と、原燃料を改質して前記燃料電池本体の燃料極に供給する燃料ガスを得る燃料改質器と、改質用水蒸気を取り出す気水分離器を組み込んだ電池冷却水系とを備えてなる燃料電池発電装置の運転方法において、
この燃料電池発電装置の発電運転を停止する際に、燃料電池本体の燃料極への燃料ガスの供給と燃料電池本体の空気極への反応空気の供給を停止するとともに、不活性ガスを不活性ガス供給源から空気極、前記気水分離器、前記燃料改質器、および、燃料極の順に経由して通流させてパージを行うこととする。
（２）また、上記（１）の運転方法において、不活性ガス供給流量設定値を一定に維持して前記パージを行い、前記不活性ガス供給源から供給される不活性ガスの流量計測値Ｑ〔m3/h〕と前記気水分離器内の圧力計測値Ｐ〔kPaG〕とに基づいて下記の（１）式から算出される抵抗係数Ｋの値が、予め決められた上限値または下限値を超えたときにアラーム信号を発信させることとする。
Ｋ＝[Ｑ2／（101.325＋Ｐ）]×103 （１）
（３）また、上記（１）または（２）の運転方法において、前記不活性ガス供給源より供給される不活性ガスの流量計測値Ｑ〔m3/h〕と、前記気水分離器の圧力計測値Ｐ〔kPaG〕が、予め定められた設定値以下となったとき、運用していた前記不活性ガス供給源から待機していた不活性ガス供給源に切替えることとする。 In the present invention, in order to achieve the above object,
(1) A fuel cell main body configured by stacking unit cells, a fuel reformer for reforming raw fuel to obtain fuel gas supplied to the fuel electrode of the fuel cell main body, and steam for reforming are taken out In a method for operating a fuel cell power generator comprising a battery cooling water system incorporating a steam separator,
When stopping the power generation operation of this fuel cell power generation device, the supply of fuel gas to the fuel electrode of the fuel cell main body and the supply of reaction air to the air electrode of the fuel cell main body are stopped and the inert gas is deactivated. Purging is performed by flowing the gas from the gas supply source through the air electrode, the steam separator, the fuel reformer, and the fuel electrode in this order.
(2) In the operation method of (1), the purge is performed while maintaining the inert gas supply flow rate setting value constant, and the flow rate measurement value Q of the inert gas supplied from the inert gas supply source is performed. The value of the resistance coefficient K calculated from the following equation (1) based on [m 3 / h] and the pressure measurement value P [kPaG] in the steam / water separator is a predetermined upper limit value or lower limit value. An alarm signal is issued when the value is exceeded.
K = [Q 2 /(101.325+P)]×10 3 (1)
(3) In the operation method of (1) or (2), the flow rate measurement value Q [m 3 / h] of the inert gas supplied from the inert gas supply source and the steam separator When the pressure measurement value P [kPaG] is equal to or lower than a predetermined set value, the inert gas supply source that has been operating is switched to the inert gas supply source that has been on standby.

（４）また、単位セルを積層して構成される燃料電池本体と、原燃料を改質して前記燃料電池本体の燃料極に供給する燃料ガスを得る燃料改質器と、改質用水蒸気を取り出す気水分離器を組み込んだ電池冷却水系とを備えてなる燃料電池発電装置で、
不活性ガス供給源と、前記不活性ガス供給源と前記空気極とを接続する第１の弁を備えた配管と、前記空気極出口に接続された第２の弁を備えた配管と、前記第２の弁の上流から分岐して前記気水分離器の気相部に接続する第３の弁を備えた配管と、原燃料を前記燃料改質器の上流の脱硫器に供給する原燃料供給遮断弁を備えた配管と、前記原燃料供給遮断弁の下流側配管と前記気水分離器の気相部とを接続する第４の弁を備えた配管と、前記脱硫器と前記改質器の間の配管と前記気水分離器の気相部とを接続する第５の弁を備えた配管とを有するものにおいて、
燃料電池発電装置の運転停止時のパージ工程の際、前記第１、第３および第４の弁を開とし、前記第２、第５および原燃料供給遮断弁を閉とする。 (4) Also, a fuel cell body configured by stacking unit cells, a fuel reformer for reforming raw fuel to obtain fuel gas supplied to the fuel electrode of the fuel cell body, and reforming steam A fuel cell power generation device comprising a battery cooling water system incorporating a steam separator for taking out
An inert gas supply source, a pipe provided with a first valve for connecting the inert gas supply source and the air electrode, a pipe provided with a second valve connected to the air electrode outlet, A pipe provided with a third valve branched from the upstream of the second valve and connected to the gas phase part of the steam separator, and a raw fuel for supplying the raw fuel to the desulfurizer upstream of the fuel reformer A pipe provided with a supply shutoff valve, a pipe provided with a fourth valve connecting a downstream pipe of the raw fuel supply shutoff valve and a gas phase part of the steam separator, the desulfurizer and the reformer In the pipe having a fifth valve for connecting the pipe between the vessel and the gas phase part of the steam separator,
During the purge process when the fuel cell power generator is stopped, the first, third and fourth valves are opened, and the second, fifth and raw fuel supply shutoff valves are closed.

燃料電池発電装置の発電運転を停止して保管状態とする際に、上記（１）のごとく、燃料ガスの燃料電池本体の燃料極への供給と反応空気の燃料電池本体の空気極への供給を停止するとともに、不活性ガスを不活性ガス供給源から空気極、前記気水分離器、前記燃料改質器、および、燃料極の順に経由して通流させてパージを行うこととすれば、１系統の不活性ガスによって系全体がパージできるので、従来法に比べて不活性ガスの消費量が少量に抑えられ、低コストでパージできることとなる。また、この方法によれば、気水分離器への空気混入が防止できるので、空気混入によって改質触媒の性能が低下するという従来の方法での難点が回避されることとなる。なお、改質触媒をパージすると運転の進行とともに若干粉化し、下流へ飛散する傾向があるため、１系統の不活性ガスによって系全体をパージする際には、上記のごとく、燃料改質器のパージに先立って空気極のパージを行うのが望ましい。
また、上記（２）のごとく、不活性ガス供給流量設定値を一定に維持してパージを行い、不活性ガス供給源から供給される不活性ガスの流量計測値Ｑ〔m3/h〕と気水分離器内の圧力計測値Ｐ〔kPaG〕とに基づいて前記（１）式から算出される抵抗係数Ｋの値が、予め決められた上限値または下限値を超えたときにアラーム信号を発信させることとすれば、ガス流量の低下や圧力の上昇等のパージガスの不調が生じると、これを的確に把握することができるので、効果的に安定したパージを行うことができる。 When the power generation operation of the fuel cell power generation device is stopped and stored, the fuel gas is supplied to the fuel electrode of the fuel cell main body and the reaction air is supplied to the air electrode of the fuel cell main body as described in (1) above. And purging by flowing an inert gas from the inert gas supply source through the air electrode, the steam separator, the fuel reformer, and the fuel electrode in this order. Since the entire system can be purged by one system of inert gas, the consumption of the inert gas can be suppressed to a small amount as compared with the conventional method, and the purge can be performed at low cost. Further, according to this method, since air can be prevented from being mixed into the steam separator, the difficulty in the conventional method that the performance of the reforming catalyst is deteriorated due to air mixing can be avoided. Note that when the reforming catalyst is purged, it tends to be slightly pulverized as the operation proceeds and scatters downstream, so when purging the entire system with one system of inert gas, as described above, It is desirable to purge the air electrode prior to purging.
Further, as described in (2) above, purge is performed while maintaining the inert gas supply flow rate set value constant, and the flow rate measurement value Q [m 3 / h] of the inert gas supplied from the inert gas supply source is An alarm signal is output when the value of the resistance coefficient K calculated from the equation (1) based on the pressure measurement value P [kPaG] in the steam separator exceeds a predetermined upper limit value or lower limit value. If it is made to transmit, since it can grasp | ascertain this accurately when the malfunction of purge gas, such as a fall of a gas flow rate and a raise of pressure, arises, the stable purge can be performed effectively.

また上記（３）のごとく、不活性ガス供給源より供給される不活性ガスの流量Ｑ〔m3/h〕と、気水分離器の圧力計測値Ｐ〔kPaG〕が、予め定められた設定値以下となったとき、運用していた不活性ガス供給源から待機していた不活性ガス供給源に切替えることとすれば、不活性ガスの供給不足を生じることなく連続的にパージすることができる。
また、上記（４）のごとく燃料電池発電装置を構成すれば、上記（１）のごとき運転方法、さらには、上記（２）、（３）のごとき運転方法が適用できるので、運転停止、保管が、低コストで、かつ性能低下を生じることなく安定に実施できることとなる。 Further, as described in (3) above, the flow rate Q [m 3 / h] of the inert gas supplied from the inert gas supply source and the pressure measurement value P [kPaG] of the steam separator are set in advance. If the inert gas supply source that has been in operation is switched to the standby inert gas supply source when the value becomes lower than the value, continuous purging can be performed without causing a shortage of inert gas supply. it can.
Further, if the fuel cell power generator is configured as described in (4) above, the operation method as described in (1) above and the operation method as described in (2) and (3) above can be applied. However, it can be stably carried out at a low cost and without causing a performance degradation.

本発明の最良の実施形態は、
燃料電池本体と、原燃料を改質して燃料ガスを得る燃料改質器と、改質用水蒸気を取り出す気水分離器を組み込んだ電池冷却水系とを備えた燃料電池発電装置の発電運転を停止して保管状態とする際、燃料ガスと反応空気の供給を停止し、不活性ガスを空気極のガス流路、次いで気水分離器の気相部に通流させ、さらに燃料改質器を経て燃料極のガス流路へと送ることによって、空気極と燃料極、並びにそれに連結された燃料改質器をパージすることにある。
さらに、このパージ工程中、不活性ガスの流量計測値Ｑ〔m3/h〕と前記気水分離器内の圧力計測値Ｐ〔kPaG〕とに基づいて（１）式から算出される抵抗係数Ｋの値が、予め決められた上限値または下限値を超えたときにアラーム信号を発信することとした。
Ｋ＝[Ｑ2／（101.325＋Ｐ）]×103 （１）
これに当り、まず調整運転時に、発電停止時のパージ工程の窒素パージ流量Ｑを0.6〔ｍ3／ｈ〕にセットした。その時の圧力計測値Ｐは 10〔kPaG〕であり、上記（１）式から、抵抗係数Ｋの初期値は、
Ｋ＝[0.62／（101.325＋10）]×103＝3.23
であった。
その後の連続運転開始後（ユーザーによる運転開始後）のパージ工程の窒素パージ流量も、0.6〔ｍ3／ｈ〕で一定制御を行う。
そして、パージ工程中に流量計測値Ｑおよび圧力計測値Ｐから算出される抵抗係数Ｋが初期値からずれる原因として、流量計または圧力計の故障、配管の閉塞、または配管からのガス漏洩が考えられるが、抵抗係数Ｋが、次のように定めた上限値または下限値を超えるとアラーム信号を発信するように設定した。
すなわち、パージ工程時の窒素流量を抑えるという観点から、窒素ガス流量計測値Ｑが前記流量設定値（0.6〔ｍ3／ｈ〕）の 25 ％増のときを上限とし、空気の混入を抑えるという観点から窒素ガス流量計測値Ｑが前記流量設定値（0.6〔ｍ3／ｈ〕）の 25 ％減のときを下限とした。そしてこれら上限値または下限値のとき、流量計測値Ｑが増減したにも関わらず、圧力計が故障して初期値表示のままであると仮定して、
Ｋmax＝[（1.25×0.6）2／（101.325＋10）]×103＝5.05
Ｋmin＝[（0.75×0.6）2／（101.325＋10）]×103＝1.82
と各々設定した。
また、燃料電池発電装置には不活性ガス供給源として窒素ガスボンベを２本以上用意しており、流量計測値Ｑ〔m3/h〕または圧力計測値Ｐ〔kPaG〕が予め定めた設定値以下になったとき（例えば、ＱまたはＰの何れかがゼロとなったとき）に、接続していた窒素ボンベから待機していた別の窒素ボンベに切替えることとした。 The best embodiment of the present invention is:
A power generation operation of a fuel cell power generator comprising a fuel cell main body, a fuel reformer for reforming raw fuel to obtain fuel gas, and a battery cooling water system incorporating a steam separator for taking out steam for reforming When stopping and storing, the supply of fuel gas and reaction air is stopped, the inert gas is passed through the gas flow path of the air electrode, then the gas phase part of the steam separator, and further the fuel reformer The air electrode, the fuel electrode, and the fuel reformer connected to the air electrode and the fuel electrode are purged by passing through the gas flow path to the gas flow path of the fuel electrode.
Further, during this purging process, the resistance coefficient calculated from the equation (1) based on the measured flow rate value Q [m 3 / h] of the inert gas and the measured pressure value P [kPaG] in the steam / water separator. An alarm signal is transmitted when the value of K exceeds a predetermined upper limit value or lower limit value.
K = [Q 2 /(101.325+P)]×10 3 (1)
In doing so, first, during the adjustment operation, the nitrogen purge flow rate Q in the purge process when power generation was stopped was set to 0.6 [m 3 / h]. The pressure measurement value P at that time is 10 [kPaG]. From the above equation (1), the initial value of the resistance coefficient K is
K = [0.6 2 /(101.325+10)]×10 3 = 3.23
Met.
Thereafter, the nitrogen purge flow rate in the purge process after the start of continuous operation (after the start of operation by the user) is also controlled at 0.6 [m 3 / h].
And, the cause of the resistance coefficient K calculated from the measured flow value Q and the measured pressure value P during the purge process deviating from the initial value may be a failure of the flow meter or pressure gauge, blockage of the pipe, or gas leakage from the pipe. However, when the resistance coefficient K exceeds the upper limit value or the lower limit value determined as follows, an alarm signal is set to be transmitted.
That is, from the viewpoint of suppressing the nitrogen flow rate during the purge process, the nitrogen gas flow rate measurement value Q is 25% of the flow rate set value (0.6 [m 3 / h]), and the upper limit is set to suppress air contamination. From the viewpoint, the lower limit was set when the measured nitrogen gas flow rate Q was 25% lower than the flow rate setting value (0.6 [m 3 / h]). And at these upper limit value or lower limit value, it is assumed that the pressure gauge has failed and the initial value display remains in spite of the increase or decrease in the flow rate measurement value Q.
K max = [(1.25 × 0.6) 2 /(101.325+10)]×10 3 = 5.05
K min = [(0.75 × 0.6) 2 /(101.325+10)]×10 3 = 1.82
And set each.
In addition, the fuel cell power generator is provided with two or more nitrogen gas cylinders as an inert gas supply source, and the flow rate measurement value Q [m 3 / h] or the pressure measurement value P [kPaG] is below a predetermined set value. When it became (for example, when either Q or P became zero), it was decided to switch from the connected nitrogen cylinder to another nitrogen cylinder that was on standby.

図１は、本発明の運転方法の実施例を適用したりん酸形燃料電池発電装置の構成を模式的に示した図である。本図に示されている燃料電池発電装置の構成部品のうち、図２の従来例と同一機能をもつ構成部品には同一の符号が付されている。図２に示されていない符号１４は不活性ガス流量計であり、符号１６は気水分離器８の圧力を計測する圧力計である。図に見られるように、本燃料電池発電装置では、発電運転時には原燃料供給遮断弁１を開状態にして都市ガスを脱硫器２、燃料改質器３、ＣＯ変成器４からなる燃料改質系に送り、高水素濃度の改質ガスに改質して燃料電池本体５の燃料極５ａへ供給するとともに、図示しない反応空気供給ラインを介して空気極５ｂへ反応空気を供給して発電を行っている。この発電運転時には、図中の原燃料供給遮断弁１と水蒸気供給遮断弁１０と排気弁１３を開状態に、また、燃料極側の不活性ガスパージ弁１１と空気極側の不活性ガスパージ弁１２と気水分離器８の不活性ガスパージ弁１５を閉状態に保持して運転される。
本燃料電池発電装置の発電運転を停止して保管状態に保持する際には、上記の原燃料給遮断弁１と水蒸気供給遮断弁１０と排気弁１３を開状態から閉状態へと移行させ、燃料極側の不活性ガスパージ弁１１と空気極側の不活性ガスパージ弁１２と気水分離器８の不活性ガスパージ弁１５を閉状態から開状態へと移行させる。このように弁を操作すると、燃料電池本体５への都市ガスと反応空気の供給が停止するとともに、不活性ガス供給源から供給されたパージ用の不活性ガスが、不活性ガスパージ弁１２を通して燃料電池本体５の空気極５ｂへと送られる。空気極５ｂのガス流路を流れてパージした不活性ガスは、次いで不活性ガスパージ弁１５を通して気水分離器８へと送られる。気水分離器８の気相を流れて排出された不活性ガスは、不活性ガスパージ弁１１を通して燃料改質装置の上流側へ供給され、脱硫器２、燃料改質器３、ＣＯ変成器４を順次流れてパージしたのち、燃料電池本体５の燃料極５ａへと送られる。燃料極５ａをパージした不活性ガスは、加熱用ヒーター７による燃料改質器３の加熱に使用されたのち、排気口から排出される。
本実施例の燃料電池発電装置では、上記のように空気極と燃料極、並びにそれに連結された燃料改質器を１系統の不活性ガスによってパージすることとしたので、従来法に比べて不活性ガスの消費量が少量に抑えられ、低コストでパージできることとなった。また、本実施例の方法でパージ操作を行なえば、気水分離器への空気混入が防止できるので、空気混入によって改質触媒の性能が低下するという従来の方法での難点が回避され、パージ操作が安定に実施できることとなる。
また、本実施例では、不活性ガス流量計１４で計測される流量計測値Ｑ〔m3/h〕と、圧力計１６の圧力計測値Ｐ〔kPaG〕とを図示しない制御装置に入力し、上記（１）式に基づき算出される抵抗係数Ｋが 1.82 を下回ったとき、または 5.05 を超えたときにアラーム信号を発信するよう設定した。これにより、不活性ガス流量計１４や圧力計１６の故障、配管の閉塞、または配管からのガス漏洩により、抵抗係数Ｋが調整運転時に算出した初期値からずれたことを検知し、これらのトラブルによる問題発生を未然に防止するための対処を講じることができる。
さらに、不活性ガス供給源として切り替え可能な２系統以上の不活性ガス供給源（窒素ボンベ）を配置し、不活性ガス流量計１４の流量計測値Ｑ〔m3/h〕および圧力計１６の圧力計測値Ｐ〔kPaG〕の何れかがゼロになった時に、自動で他の系統に切り替えを行うこととし、またこれと同時に不活性ガス交換を知らせるアラームを発することとしたので、不活性ガス欠乏のトラブルを未然に防止することができる。 FIG. 1 is a diagram schematically showing the configuration of a phosphoric acid fuel cell power generator to which an embodiment of the operation method of the present invention is applied. Of the components of the fuel cell power generator shown in the figure, components having the same functions as those of the conventional example of FIG. 2 are denoted by the same reference numerals. Reference numeral 14 not shown in FIG. 2 is an inert gas flow meter, and reference numeral 16 is a pressure gauge that measures the pressure of the steam separator 8. As shown in the figure, in this fuel cell power generator, the fuel reforming system comprising the desulfurizer 2, the fuel reformer 3, and the CO converter 4 with the raw fuel supply shut-off valve 1 opened during power generation operation. To the fuel electrode 5a of the fuel cell body 5 and supply the reaction air to the air electrode 5b via a reaction air supply line (not shown) to generate power. Is going. During this power generation operation, the raw fuel supply cutoff valve 1, the water vapor supply cutoff valve 10 and the exhaust valve 13 in the drawing are opened, and the inert gas purge valve 11 on the fuel electrode side and the inert gas purge valve 12 on the air electrode side. And the inert gas purge valve 15 of the steam separator 8 is kept closed.
When stopping the power generation operation of the fuel cell power generation device and keeping it in the storage state, the raw fuel supply cutoff valve 1, the water vapor supply cutoff valve 10 and the exhaust valve 13 are shifted from the open state to the closed state, The inert gas purge valve 11 on the fuel electrode side, the inert gas purge valve 12 on the air electrode side, and the inert gas purge valve 15 of the steam separator 8 are shifted from the closed state to the open state. When the valve is operated in this way, the supply of the city gas and the reaction air to the fuel cell main body 5 is stopped, and the purge inert gas supplied from the inert gas supply source passes through the inert gas purge valve 12 as fuel. It is sent to the air electrode 5b of the battery body 5. The inert gas purged by flowing through the gas flow path of the air electrode 5 b is then sent to the steam separator 8 through the inert gas purge valve 15. The inert gas discharged through the gas phase of the steam separator 8 is supplied to the upstream side of the fuel reformer through the inert gas purge valve 11, and the desulfurizer 2, the fuel reformer 3, and the CO converter 4. Are sequentially flowed and purged, and then sent to the fuel electrode 5a of the fuel cell body 5. The inert gas purged from the fuel electrode 5a is used for heating the fuel reformer 3 by the heater 7 and then discharged from the exhaust port.
In the fuel cell power generator of this embodiment, the air electrode, the fuel electrode, and the fuel reformer connected to the air electrode, the fuel electrode, and the fuel reformer connected thereto are purged by one inert gas as described above. The consumption of the active gas was suppressed to a small amount, and it was possible to purge at a low cost. Further, if the purge operation is performed by the method of the present embodiment, since air can be prevented from being mixed into the steam separator, the disadvantage of the conventional method in which the performance of the reforming catalyst is deteriorated due to air mixing can be avoided. The operation can be carried out stably.
In this embodiment, the flow rate measurement value Q [m 3 / h] measured by the inert gas flow meter 14 and the pressure measurement value P [kPaG] of the pressure gauge 16 are input to a control device (not shown), An alarm signal is set to be transmitted when the resistance coefficient K calculated based on the above equation (1) falls below 1.82 or exceeds 5.05. As a result, it is detected that the resistance coefficient K has deviated from the initial value calculated during the adjustment operation due to a failure of the inert gas flow meter 14 or the pressure gauge 16, blockage of the pipe, or gas leakage from the pipe. It is possible to take measures to prevent the occurrence of problems due to.
Further, two or more inert gas supply sources (nitrogen cylinders) that can be switched as inert gas supply sources are arranged, and the flow rate measurement value Q [m 3 / h] of the inert gas flow meter 14 and the pressure gauge 16 When any of the measured pressure values P [kPaG] becomes zero, the system is automatically switched to another system, and at the same time, an alarm is given to notify the replacement of the inert gas. A deficiency trouble can be prevented in advance.

以上述べたように、本発明の運転方法により燃料電池発電装置のパージ操作を行えば、不活性ガスの消費量が少量に抑えられて、低コストでパージが実施可能となるとともに、気水分離器への空気混入が防止できるので、空気混入によって改質触媒の性能が低下するという従来の方法での難点が回避され、パージ操作が安定に実施できるので、各種の燃料電池発電装置の運転方法として好適に利用されるものと期待される。   As described above, if the purge operation of the fuel cell power generation device is performed by the operation method of the present invention, the consumption of the inert gas can be suppressed to a small amount, the purge can be performed at low cost, and the air-water separation is performed. As a result, it is possible to prevent the trouble of the conventional method that the performance of the reforming catalyst is deteriorated due to air mixing, and the purge operation can be stably performed. It is expected that it will be suitably used.

本発明の運転方法を適用した燃料電池発電装置の概略構成を模式的に示した図The figure which showed typically schematic structure of the fuel cell power generation device to which the driving | running method of this invention was applied. 従来の燃料電池発電装置の発電運転を停止して保管状態に保持した際の概略構成を模式的に示した図The figure which showed typically the schematic structure at the time of stopping the electric power generation driving | operation of the conventional fuel cell power generation device, and hold | maintaining in the storage state

符号の説明Explanation of symbols

１ 原燃料供給遮断弁
３ 燃料改質器
５ 燃料電池本体
６ 保温ヒーター
７ 加熱用ヒーター
８ 気水分離器
９ 大気開放弁
１０ 水蒸気供給遮断弁
１１ 不活性ガスパージ弁（燃料改質器および燃料極側）
１２ 不活性ガスパージ弁（空気極側）
１３ 排気弁
１４ 不活性ガス流量計
１５ 不活性ガスパージ弁（気水分離器）
１６ 圧力計
DESCRIPTION OF SYMBOLS 1 Raw fuel supply shut-off valve 3 Fuel reformer 5 Fuel cell main body 6 Heat insulation heater 7 Heating heater 8 Air-water separator 9 Atmospheric release valve 10 Water vapor supply shut-off valve 11 Inert gas purge valve (fuel reformer and fuel electrode side) )
12 Inert gas purge valve (air electrode side)
13 Exhaust valve 14 Inert gas flow meter 15 Inert gas purge valve (gas / water separator)
16 Pressure gauge

Claims (4)

単位セルを積層して構成される燃料電池本体と、原燃料を改質して前記燃料電池本体の燃料極に供給する燃料ガスを得る燃料改質器と、改質用水蒸気を取り出す気水分離器を組み込んだ電池冷却水系とを備えてなる燃料電池発電装置の運転方法において、
該燃料電池発電装置の発電運転を停止する際に、燃料ガスの燃料電池本体の燃料極への供給と反応空気の燃料電池本体の空気極への供給を停止するとともに、不活性ガスを不活性ガス供給源から空気極、前記気水分離器、前記燃料改質器、および、燃料極の順に経由して通流させてパージを行うことを特徴とする燃料電池発電装置の運転方法。 A fuel cell main body configured by stacking unit cells, a fuel reformer for reforming raw fuel to obtain fuel gas supplied to the fuel electrode of the fuel cell main body, and an air-water separation for taking out reforming steam In a method for operating a fuel cell power generator comprising a battery cooling water system incorporating a vessel,
When stopping the power generation operation of the fuel cell power generator, the supply of fuel gas to the fuel electrode of the fuel cell body and the supply of reaction air to the air electrode of the fuel cell body are stopped and the inert gas is deactivated A method of operating a fuel cell power generator, wherein purging is performed by flowing a gas supply source through an air electrode, the steam separator, the fuel reformer, and the fuel electrode in this order. 請求項１に記載の燃料電池発電装置の運転方法において、前記パージは不活性ガス供給流量設定値を一定に維持して行うものであり、前記不活性ガス供給源から供給される不活性ガスの流量計測値Ｑ〔m3/h〕と前記気水分離器内の圧力計測値Ｐ〔kPaG〕とに基づいて（１）式から算出される抵抗係数Ｋの値が、予め決められた上限値または下限値を超えたときにアラーム信号を発信することを特徴とする燃料電池発電装置の運転方法。
Ｋ＝[Ｑ2／（101.325＋Ｐ）]×103 （１） 2. The operation method of a fuel cell power generator according to claim 1, wherein the purging is performed by maintaining a constant set value of an inert gas supply flow rate, and the inert gas supplied from the inert gas supply source is The value of the resistance coefficient K calculated from the equation (1) based on the flow rate measurement value Q [m 3 / h] and the pressure measurement value P [kPaG] in the steam / water separator is a predetermined upper limit value. Alternatively, an alarm signal is transmitted when the lower limit value is exceeded.
K = [Q 2 /(101.325+P)]×10 3 (1) 請求項１または２に記載の燃料電池発電装置の運転方法において、前記不活性ガス供給源より供給される不活性ガスの流量Ｑ〔m3/h〕と、前記気水分離器の圧力計測値Ｐ〔kPaG〕が、予め定められた設定値以下となったとき、運用していた前記不活性ガス供給源から待機していた不活性ガス供給源に切替えることを特徴とする燃料電池発電装置の運転方法。 The operating method of the fuel cell power generator according to claim 1 or 2, wherein the flow rate Q [m 3 / h] of the inert gas supplied from the inert gas supply source and the pressure measurement value of the steam separator. When the P [kPaG] is equal to or lower than a predetermined set value, the inert gas supply source that has been in operation is switched to the inert gas supply source that has been on standby. how to drive. 単位セルを積層して構成される燃料電池本体と、原燃料を改質して前記燃料電池本体の燃料極に供給する燃料ガスを得る燃料改質器と、改質用水蒸気を取り出す気水分離器を組み込んだ電池冷却水系とを備えてなる燃料電池発電装置において、
不活性ガス供給源と、前記不活性ガス供給源と前記空気極とを接続する第１の弁を備えた配管と、前記空気極出口に接続された第２の弁を備えた配管と、前記第２の弁の上流から分岐して前記気水分離器の気相部に接続する第３の弁を備えた配管と、原燃料を前記燃料改質器の上流の脱硫器に供給する原燃料供給遮断弁を備えた配管と、前記原燃料供給遮断弁の下流側配管と前記気水分離器の気相部とを接続する第４の弁を備えた配管と、前記脱硫器と前記改質器の間の配管と前記気水分離器の気相部とを接続する第５の弁を備えた配管とを有し、
燃料電池発電装置の運転停止時のパージ工程の際、前記第１、第３および第４の弁が開、前記第２、第５および原燃料供給遮断弁が閉となることを特徴とする燃料電池発電装置。
A fuel cell main body configured by stacking unit cells, a fuel reformer for reforming raw fuel to obtain fuel gas supplied to the fuel electrode of the fuel cell main body, and an air-water separation for taking out reforming steam In a fuel cell power generator comprising a battery cooling water system incorporating a vessel,
An inert gas supply source, a pipe provided with a first valve for connecting the inert gas supply source and the air electrode, a pipe provided with a second valve connected to the air electrode outlet, A pipe provided with a third valve branched from the upstream of the second valve and connected to the gas phase part of the steam separator, and a raw fuel for supplying the raw fuel to the desulfurizer upstream of the fuel reformer A pipe provided with a supply shutoff valve, a pipe provided with a fourth valve connecting a downstream pipe of the raw fuel supply shutoff valve and a gas phase part of the steam separator, the desulfurizer and the reformer A pipe having a fifth valve for connecting a pipe between the vessels and a gas phase part of the steam separator,
The fuel is characterized in that the first, third, and fourth valves are opened and the second, fifth, and raw fuel supply shut-off valves are closed during the purge step when the operation of the fuel cell power generator is stopped. Battery power generator.
JP2007234908A 2007-09-11 2007-09-11 Fuel cell power generation device and its operation method Pending JP2009070590A (en)

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