JP2004095370A

JP2004095370A - Fuel cell power generation system and its operation method

Info

Publication number: JP2004095370A
Application number: JP2002255498A
Authority: JP
Inventors: Hiromi Sasaki; 佐々木　広美; Tadashi Kimura; 木村　正
Original assignee: Toshiba International Fuel Cells Corp
Current assignee: Toshiba Energy Systems and Solutions Corp
Priority date: 2002-08-30
Filing date: 2002-08-30
Publication date: 2004-03-25
Anticipated expiration: 2022-08-30
Also published as: JP4049640B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generation system of a high reliability and its operation method by further improving an impurity absorption performance of a pretreatment device, improving maintenance of the pretreatment device, and coping well with degradation of an impurity removal performance. <P>SOLUTION: With the fuel cell power generation system provided with a pretreatment device 1 for treating impurities contained in biogas generated from organic wastes and a fuel cell generation device 2 for electrochemically generating power by reforming fuel treated at the pretreatment device 1, the pretreatment device 1 has at least two or more vessels 5, 7 containing activated carbon connected in series. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、有機性廃棄物から発生するバイオガスを燃料として利用する燃料電池発電システムおよびその運転方法に関する。
【０００２】
【従来の技術】
従来、燃料電池発電システムでは、都市ガスや液化石油ガス（ＬＰＧ）等の炭化系水素を燃料としたものが大部分を占め、下水やし尿、あるいは生ゴミや食品廃水等の有機性廃棄物をバクテリアで分解させて発生させ、メタンを６０％以上含んだバイオガスに適用されるものは極く限られていた。
【０００３】
また、バイオガス燃料中に含まれる不純物には、硫化水素、アンモニア、塩素等がある。これら不純物を予め処理する前処理装置は、不純物の性状に合せて処理できるように設計されている。前処理装置の処理方法には、例えば水洗法、アルカリ吸着法、酸化吸着法、またはこれらを組み合せたものが使用されている。そして、これらの手法を適用した前処理装置は、不純物の濃度を数十ｐｐｍまで除去した後、最終的に活性炭吸着法を用いて不純物の濃度を数ｐｐｍ以下に低下させていた。
【０００４】
【発明が解決しようとする課題】
バイオガス燃料に含まれる不純物は、上述の手法を用いて前処理を行っているが、実際には適用形態や適用場所、その他の要因がケース毎にそれぞれ異なるため、充分に性状等を確認できないまま前処理を行っていた。このため、不純物を充分に前処理しないまま燃料電池発電装置の改質器等に供給され、改質器等に充填されている触媒を被毒させることがあった。
【０００５】
ところで、バイオガス中には、硫化水素、アンモニア、塩素等の不純物以外に、有機性廃棄物に含まれる高分子化合物から発生する炭素数９〜１３の飽和炭化水素、トルエンやシリコンから発生する珪素数１〜５のシロキサン等の炭化水素化合物が数十ｐｐｍ程度含まれている場合がある。
【０００６】
これらの炭化水素系化合物は、水洗法、アルカリ吸着法、酸化吸着法では吸着せず、活性炭に吸着される性質を持っている。
【０００７】
したがって、従来の前処理装置では、炭化水素系化合物の活性炭への吸着を考慮していないため、活性炭の量や種類の選定が不適切となり、その結果として活性炭の寿命が短くなったり、硫化水素、アンモニア、塩素等の不純物が充分に除去できない等の問題点があった。
【０００８】
本発明は、このような点を考慮してなされたものであり、前処理装置の不純物吸着性能をより一層向上させるとともに、前処理装置の保守の改善を図り、不純物除去性能の劣化に充分に対処して信頼性の高い燃料電池発電システムおよびその運転方法を提供することを目的とする。
【０００９】
【課題を解決するための手段】
本発明に係る燃料電池発電システムは、上述の目的を達成するために、請求項１に記載したように、有機性廃棄物から発生したバイオガスに含まれる不純物を処理する前処理装置と、この前処理装置で処理した燃料を改質させて電気化学的に発電する燃料電池発電装置とを備えた燃料電池発電システムにおいて、前記前処理装置は、活性炭を充填する容器を少なくとも二つ以上の複数基を直列に接続したものである。
【００１０】
また、本発明に係る燃料電池発電システムは、上述の目的を達成するために、請求項２に記載したように、複数基の容器のうち、一つはバイオガスに含まれた飽和炭化水素やその化合物を吸着する汎用活性炭を充填した第１容器と、他はバイオガスに含まれた酸、塩基、硫黄のうち、少なくとも一つ以上を吸着する機能性活性炭を充填した第２容器とを備えたものである。
【００１１】
また、本発明に係る燃料電池発電システムは、上述の目的を達成するために、請求項３に記載したように、第２容器に充填した機能性活性炭は、硫黄化合物吸着用活性炭、アンモニア吸着用活性炭、塩基吸着用活性炭を層状に充填したものである。
【００１２】
また、本発明に係る燃料電池発電システムは、上述の目的を達成するために、請求項４に記載したように、第１容器は、これを２基に分割して並列に配置しさらに第１バイパス系を備える一方、第２容器は、１基のみとし、第２バイパス系を備えたものである。
【００１３】
また、本発明に係る燃料電池発電システムは、上述の目的を達成するために、請求項５に記載したように、有機性廃棄物から発生したバイオガスに含まれる不純物を処理する前処理装置と、この前処理装置で処理した燃料を改質させて電気化学的に発電する燃料電池発電装置とを備えた燃料電池発電システムにおいて、前記前処理装置と前記燃料電池発電装置との間にバイオガスに含まれる不純物を検出する検出器と、この検出器から検出した信号に基づいてバイオガスの供給を遮断させる遮断弁とを備えたものである。
【００１４】
また、本発明に係る燃料電池発電システムは、上述の目的を達成するために、請求項６に記載したように、遮断弁は、バイオガスに含まれる不純物を検出した実検出信号に、予め定められた設定許容信号とを突き合せ、偏差が出たとき、その偏差に基づいて遮断指令を演算するガス濃度演算器を備えたものである。
【００１５】
また、本発明に係る燃料電池発電システムの運転方法は、上述の目的を達成するために、請求項７に記載したように、有機性廃棄物から発生したバイオガスに含まれる不純物を処理する前処理装置と、この前処理装置で処理した燃料を改質させて電気化学的に発電する燃料電池発電装置とを備える燃料電池発電システムにおいて、請求項４に示す２基の第一容器よりなる前処理装置を運転させる際、一方の第一容器を運転させ、残りの第一容器を待機させておき、運転中の第一容器の活性炭の交換の際、待機中の第一容器に切り替えて運転を継続させる方法である。
【００１６】
また、本発明に係る燃料電池発電システムの運転方法は、上述の目的を達成するために、請求項８に記載したように、有機性廃棄物から発生したバイオガスに含まれる不純物を処理する前処理装置と、この前処理装置で処理した燃料を改質させて電気化学的に発電する燃料電池発電装置とを備える燃料電池発電システムにおいて、汎用活性炭を充填した第１容器と、機能性活性炭を充填した第２容器とを備える前記前処理装置を運転させる際、運転中の前記第２容器に充填した機能性活性炭を交換するとき、バイパス系を使用し、前記第２容器の機能性活性炭を交換する方法である。
【００１７】
【発明の実施の形態】
以下、本発明に係る燃料電池発電システムおよびその運転方法の実施形態を図面および図面に付した符号を引用して説明する。
【００１８】
図１は、本発明に係る燃料電池発電システムの第１実施形態を示す概略系統図である。
【００１９】
本実施形態に係る燃料電池発電システムは、大別して前処理装置１と燃料電池発電装置２とを備えた構成になっている。
【００２０】
前処理装置１は、バイオガス入口３の下流側に汎用活性炭９を充填する第１容器５と、機能性活性炭１０を充填する第２容器７を備えている。
【００２１】
また、前処理装置１は、バイオガス出口８を燃料電池発電装置２に接続させている。なお、燃料電池発電装置２は、脱硫器、改質器、変成器、燃料電池本体等を備えているが、本実施形態の直接的な対象になっていないので、ここではその説明を省略する。
【００２２】
第１容器５には、炭素数９〜１３の飽和炭化水素、トルエンや珪素数１〜５のシロキサン等の炭化水素系化合物を吸着する汎用活性炭９が充填されている。
【００２３】
また第２容器７には、活性炭に化学処理し、酸性ガス、塩基性ガス、中性ガスへの吸着能力を増加させた機能性活性炭１０が充填されている。
【００２４】
この機能性活性炭１０は、硫化水素および硫黄化合物を吸着させるイオウ化合物吸着用活性炭１１と、アンモニアや塩基性ガスを吸着させるアンモニア吸着用活性炭１２と、塩素や塩酸を吸着させる塩素吸着用活性炭１３の３種類を層状に充填して使用している。
【００２５】
なお、汎用活性炭９および機能性活性炭１０は、バイオガス中の炭化水素化合物、硫化水素、アンモニア、塩素の濃度と活性炭の吸着容量との関係から寿命および交換頻度が経済的に好ましくなるよう、その充填量が決定される。
【００２６】
このような構成を備えた燃料電池発電システム、特に前処理装置１において、下水やし尿あるいは生ゴミや食品廃水の有機性廃棄物からメタン発酵処理により生成されたバイオガスは、水洗法、アルカリ吸着法、酸化吸着法のうち、いずれかの方法で硫黄化合物、酸、塩基等の不純物の濃度をそれぞれ数十ｐｐｍまで吸着した後、バイオガス入口３に供給される。
【００２７】
バイオガスが第１容器５に充填された汎用活性炭９を通る間に、バイオガスに含まれる炭素数９〜１３の飽和炭化水素や珪素数１〜５のシロキサン等の炭化水素系化合物が吸着される。なお、硫黄化合物、酸、塩基性の不純物もある程度吸着される。
【００２８】
次に、バイオガスが第２容器７に充填された機能性活性炭１０を通る間に、バイオガスに含まれる硫化水素および硫黄化合物が硫黄化合物吸着用活性炭１１で吸着される。また、アンモニアや塩基性ガスは、アンモニア吸着用活性炭１２で吸着される。さらに、塩素や塩酸は、塩素吸着用活性炭１３で吸着される。
【００２９】
そして、第２容器７の出口では、硫黄化合物が０．１ｐｐｍ以下、アンモニアおよび塩素の各濃度が０．０５ｐｐｍ以下に低減されて燃料電池発電装置２に供給される。
【００３０】
このように、本実施形態は、バイオガスに含まれている不純物のうち、水洗法、アルカリ吸着法、酸化吸着法等を用いても従来の前処理装置で吸着できなかった炭化水素系化合物を第１容器５の汎用活性炭９で吸着させ、さらに第２容器７の機能性活性炭１０で硫黄化合物、酸、塩基等の不純物を吸着させてその濃度を低減させ、改質器等に用いている触媒の被毒を防止して燃料電池発電システムに長期間に亘って安定運転を行わせることができる。
【００３１】
図２は、本発明に係る燃料電池発電システムの第２実施形態を示す概略系統図である。なお、第１実施形態の構成部品と同一構成部品には同一符号を付す。
【００３２】
本発明に係る燃料電池発電システムは、運転中に第１容器５の汎用活性炭９が、予め決められた交換時期になった場合や例えば性能劣化等、何らかの事情で交換を余儀なくする場合、第１容器５の交換ができるように、第１容器５と並列に第１副容器１６を設置するとともに、第１容器５の入口側および出口側のそれぞれに第１容器用入口止め弁１４および第１容器用出口止め弁１５を設ける一方、第１副容器１６の入口側および出口側のそれぞれにも第１副容器用入口止め弁１７および第１副容器用出口止め弁１８を設け、さらに、第１容器５と第１副容器１６との間に第１バイパス管１９を設け、第１バイパス管１９に第１バイパス容器用入口止め弁２０、第１バイパス容器用出口止め弁２１、第１バイパス副容器用入口止め弁２２、第１バイパス副容器用出口止め弁２３を設けたものである。
【００３３】
また、本発明に係る燃料電池発電システムは、上述と同様に、運転中に第２容器７の機能性活性炭１０が、予め決められた交換時期になった場合や例えば、性能劣化等何らかの事情で交換を余儀なくする場合、第２容器７の機能性活性炭１０の交換ができるように、第２容器７の入口側および出口側のそれぞれに第２容器用入口止め弁２４および第２容器用出口止め弁２５を設けるとともに、第２容器７に第２バイパス弁２６を介装した第２バイパス管２７を設けたものである。
【００３４】
次に、燃料電池発電システムの運転方法を説明する。
【００３５】
上述の構成を備えた燃料電池発電システムにおいて、通常運転時、第１容器５は運転中、第１副容器１６は待機中になっている。このとき、第１容器用入口止め弁１４および第１容器用出口止め弁１５は「開」、第１副容器用入口止め弁１７および第１副容器用出口止め弁１８は「閉」、第１バイパス管１９の第１バイパス容器用入口止め弁２０、第１バイパス容器用出口止め弁２１、第１バイパス副容器用入口止め弁２２、第１バイパス副容器用出口止め弁２３は、「閉」になっている。
【００３６】
この状態から、第１容器５の汎用活性炭４の交換時期がきたとき、第１副容器用入口止め弁１７および第１副容器用出口弁１８を「開」、第１容器用入口止め弁１４、第１容器用出口止め弁１５を「閉」とし、（注：順序を逆にした）第１容器５から第１副容器１６に運転を切り替えると、第１容器５の汎用活性炭９は容易に交換することができる。
【００３７】
また、第２容器７においても、運転中、機能性活性炭１０の交換時期がきたとき、第２バイパス管２７の第２バイパス弁２６を「開」、第２容器用入口止め弁２４および第２容器用出口止め弁２５を「閉」とし、（注：順序を逆にした）第２バイパス管２７を使用することにより、第２容器７の機能性活性炭１０は交換することができる。
【００３８】
この場合、第１容器５の汎用活性炭９も硫黄化合物、酸、塩基性の不純物の吸着能力を有しているため第２容器７の機能性活性炭１０の交換作業による短期間のバイパス運転においても燃料電池発電装置２の改質器等の触媒を被毒させることはない。
【００３９】
なお、第１容器５と第１副容器１６とを使用し、汎用活性炭９の能力を充分に活用する場合、第１バイパス管１９を使用し、第１容器５と第１副容器１６とを連通させて運転させてもよい。この場合、第１容器用入口止め弁１４を「開」、第１容器用出口止め弁１５を「閉」、第１副容器用入口止め弁１７を「閉」、第１副容器用出口止め弁１８を「開」、第１バイパス容器用出口止め弁２０を「閉」、第１バイパス容器用出口止め弁２１を「開」、第１バイパス副容器用入口止め弁２２を「開」、第１バイパス副容器用出口止め弁２３を「閉」とする。
【００４０】
このように、本実施形態は、第１容器５と並列に第１副容器１６を設け、第１容器５と第１副容器１６との間に第１バイパス管１９を設けるとともに、第２容器７にも第２バイパス管２７を設けたので、吸着能力の低下した汎用活性炭９および機能性活性炭１０を容易に交換させて吸着能力を高く維持することができる。
【００４１】
図３は、本発明に係る燃料電池発電システムの第３実施形態を示す概略系統図である。なお、第１実施形態の構成部品と同一構成部品には同一符号を付す。
【００４２】
本実施形態に係る燃料電池発電システムは、前処理装置１の第２容器７とバイオガス出口８との間に検出器２８とガス濃度演算器２９を備えた遮断弁３０とを設けたものである。
【００４３】
ここで、検出器２８は、燃料電池発電装置２の改質器等の触媒を被毒させる不純物、例えば、硫化水素、アンモニア、塩素、酸素等のうち、少なくとも一つ以上の濃度を検出できるようになっている。
【００４４】
また、ガス濃度演算器２９は、検出器２８から検出された実ガス濃度と比較する予め設定した許容濃度信号を入力しておき、許容値を超えて偏差が出たとき、偏差を演算して警報を出すとともに、遮断弁３０を閉じる指令を出すようになっている。
【００４５】
このような構成を備えた燃料電池発電システムにおいて、バイオガスは、第２容器７の機能性活性炭１０でバイオガス中の不純物が十分吸着されない状態で検出器２８に流れると、ここで燃料電池発電装置２の改質器等の触媒を被毒させる、例えば硫化水素、アンモニア、塩素、酸素のうち、いずれかのガス濃度が検出される。
【００４６】
検出されたガス濃度は、ガス濃度演算器２９に与えられ、予め定められた許容値と比較される。ガス濃度演算器２９は、偏差が出ると、その偏差を基に警報信号と遮断指令とを演算し、警報を出すとともに、遮断弁３０を閉鎖させる。
【００４７】
このように、本実施形態は、第２容器７の出口側に検出器２８とガス濃度演算器２９を備えた遮断弁３０とを設け、検出器２８で検出されたバイオガス濃度がガス濃度演算器２９の許容設定値を超えたとき、警報信号を出し、遮断弁３０を遮断させる指令を出すので、燃料電池発電装置２に安全かつ安定運転を行わせることができる。
【００４８】
【発明の効果】
以上の説明の通り、本発明に係る燃料電池発電システムおよびその運転方法によれば、バイオガス中の被毒ガスとなる不純物を吸着する前処理装置において、汎用活性炭と機能性活性炭とを組み合せることにより、優れた不純物吸着性能を発揮するとともに、活性炭の寿命を改善して運転コストを低減することができる。
【００４９】
また、運転中、活性炭を交換できる手段を備えて断続的に運転を続行させるので、稼働率を向上させることができる。
【００５０】
さらに、バイオガス中の不純物のガス濃度検出手段と不純物の濃度が高いとき、ガスの流れを遮断する手段とを組み合せたので、安全かつ安定運転を維持させることができる。
【図面の簡単な説明】
【図１】本発明に係る燃料電池発電システムの第１実施形態を示す概略系統図。
【図２】本発明に係る燃料電池発電システムの第２実施形態を示す概略系統図。
【図３】本発明に係る燃料電池発電システムの第３実施形態を示す概略系統図。
【符号の説明】
１　前処理装置
２　燃料電池発電装置
３　バイオガス
５　第１容器
７　第２容器
８　バイオガス出口
９　汎用活性炭
１０　機能性活性炭
１１　硫黄化合物吸着用活性炭
１２　アンモニア吸着用活性炭
１３　塩素吸着用活性炭
１４　第１容器用入口止め弁
１５　第１容器用出口止め弁
１６　第１副容器
１７　第１副容器用入口止め弁
１８　第１副容器用出口止め弁
１９　第１バイパス管
２０　第１バイパス容器用入口止め弁
２１　第１バイパス容器用出口止め弁
２２　第１バイパス副容器用入口止め弁
２３　第１バイパス副容器用出口止め弁
２４　第２容器用入口止め弁
２５　第２容器用出口止め弁
２６　第２バイパス弁
２７　第２バイパス管
２８　検出器
２９　ガス濃度演算器
３０　遮断弁[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell power generation system using biogas generated from organic waste as a fuel and a method of operating the same.
[0002]
[Prior art]
Conventionally, most fuel cell power generation systems use hydrocarbons, such as city gas and liquefied petroleum gas (LPG), as fuels, and discharge organic wastes such as sewage, human waste, garbage and food wastewater. The application to biogas containing more than 60% methane generated by decomposition by bacteria has been extremely limited.
[0003]
The impurities contained in the biogas fuel include hydrogen sulfide, ammonia, chlorine and the like. The pre-treatment device for pre-treating these impurities is designed so that the impurities can be treated according to the properties of the impurities. As the treatment method of the pretreatment device, for example, a water washing method, an alkali adsorption method, an oxidation adsorption method, or a combination thereof is used. The pretreatment apparatus to which these methods are applied removes the impurity concentration to several tens ppm, and finally reduces the impurity concentration to several ppm or less by using the activated carbon adsorption method.
[0004]
[Problems to be solved by the invention]
The impurities contained in the biogas fuel are pre-treated using the above-mentioned method, but in actuality the application form, application place, and other factors differ from case to case, and the properties etc. cannot be sufficiently confirmed. Pre-processing was performed as it was. For this reason, the impurities supplied to the reformer or the like of the fuel cell power generator without sufficient pretreatment may poison the catalyst filled in the reformer or the like.
[0005]
Incidentally, in biogas, in addition to impurities such as hydrogen sulfide, ammonia, and chlorine, a saturated hydrocarbon having 9 to 13 carbon atoms generated from a high molecular compound contained in organic waste, and silicon generated from toluene and silicon are included. Hydrocarbon compounds such as siloxanes of Formulas 1 to 5 may be contained in an amount of about several tens ppm.
[0006]
These hydrocarbon compounds are not adsorbed by a water washing method, an alkali adsorption method, or an oxidation adsorption method, but have a property of being adsorbed by activated carbon.
[0007]
Therefore, in the conventional pretreatment device, since the adsorption of the hydrocarbon compound to the activated carbon is not considered, the selection of the amount and the type of the activated carbon becomes inappropriate, and as a result, the life of the activated carbon is shortened, And impurities such as ammonia and chlorine cannot be sufficiently removed.
[0008]
The present invention has been made in view of the above points, and further improves the impurity adsorption performance of the pretreatment device, improves the maintenance of the pretreatment device, and sufficiently reduces the impurity removal performance. It is an object of the present invention to provide a highly reliable fuel cell power generation system and an operation method thereof.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a fuel cell power generation system according to the present invention includes, as described in claim 1, a pretreatment device for treating impurities contained in biogas generated from organic waste, A fuel cell power generation system comprising: a fuel cell power generation device that reforms the fuel processed by the pretreatment device to electrochemically generate power; wherein the pretreatment device includes at least two or more containers filled with activated carbon. Groups are connected in series.
[0010]
Further, in order to achieve the above object, the fuel cell power generation system according to the present invention includes, as described in claim 2, one of the plurality of containers, wherein one of the plurality of containers includes a saturated hydrocarbon contained in biogas or A first container filled with general-purpose activated carbon that adsorbs the compound, and a second container filled with a functional activated carbon that adsorbs at least one of the other acids, bases, and sulfur contained in the biogas are provided. It is a thing.
[0011]
Further, in the fuel cell power generation system according to the present invention, in order to achieve the above object, as described in claim 3, the functional activated carbon filled in the second container is activated carbon for adsorbing sulfur compounds and activated carbon for adsorbing ammonia. Activated carbon and activated carbon for base adsorption are packed in layers.
[0012]
In the fuel cell power generation system according to the present invention, in order to achieve the above object, as described in claim 4, the first container is divided into two units and arranged in parallel. While a bypass system is provided, only one second container is provided, and a second bypass system is provided.
[0013]
Further, in order to achieve the above object, a fuel cell power generation system according to the present invention includes, as described in claim 5, a pretreatment device for treating impurities contained in biogas generated from organic waste. A fuel cell power generation system comprising: a fuel cell power generation device that reforms fuel processed by the pretreatment device to electrochemically generate power; wherein a biogas is provided between the pretreatment device and the fuel cell power generation device. And a shut-off valve for shutting off the supply of biogas based on a signal detected from the detector.
[0014]
Further, in the fuel cell power generation system according to the present invention, in order to achieve the above-described object, as described in claim 6, the shut-off valve is provided in advance with an actual detection signal that detects impurities contained in the biogas. A gas concentration calculator that compares the set allowable signal and calculates a shutoff command based on the deviation when a deviation occurs.
[0015]
Further, in order to achieve the above object, the operating method of the fuel cell power generation system according to the present invention, as described in claim 7, before processing impurities contained in biogas generated from organic waste. In a fuel cell power generation system comprising a processing device and a fuel cell power generation device that reforms the fuel processed by the pretreatment device to electrochemically generate power, the fuel cell power generation system includes two first containers according to claim 4. When operating the processing apparatus, one of the first containers is operated and the other first container is kept on standby, and when replacing the activated carbon in the first container during operation, the operation is switched to the first container on standby. Is a method of continuing.
[0016]
Further, in order to achieve the above object, the operating method of the fuel cell power generation system according to the present invention, as described in claim 8, before processing impurities contained in biogas generated from organic waste. In a fuel cell power generation system including a processing device and a fuel cell power generation device that reforms fuel processed by the pretreatment device to electrochemically generate power, a first container filled with general-purpose activated carbon, and a functional activated carbon are provided. When operating the pretreatment device including the filled second container, when replacing the functional activated carbon filled in the operating second container, using a bypass system, the functional activated carbon of the second container is replaced How to replace.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a fuel cell power generation system and an operation method thereof according to the present invention will be described with reference to the drawings and reference numerals attached to the drawings.
[0018]
FIG. 1 is a schematic system diagram showing a first embodiment of a fuel cell power generation system according to the present invention.
[0019]
The fuel cell power generation system according to the present embodiment is roughly configured to include a pretreatment device 1 and a fuel cell power generation device 2.
[0020]
The pretreatment device 1 includes a first container 5 for filling general-purpose activated carbon 9 downstream of the biogas inlet 3 and a second container 7 for filling functional activated carbon 10.
[0021]
The pretreatment device 1 has the biogas outlet 8 connected to the fuel cell power generation device 2. Although the fuel cell power generator 2 includes a desulfurizer, a reformer, a shift converter, a fuel cell main body, and the like, it is not a direct object of the present embodiment, and a description thereof will be omitted here. .
[0022]
The first container 5 is filled with general-purpose activated carbon 9 that adsorbs a saturated hydrocarbon having 9 to 13 carbon atoms and a hydrocarbon-based compound such as toluene and siloxane having 1 to 5 silicon atoms.
[0023]
The second container 7 is filled with a functional activated carbon 10 obtained by chemically treating activated carbon and increasing its ability to adsorb acidic gas, basic gas, and neutral gas.
[0024]
This functional activated carbon 10 includes activated carbon 11 for sulfur compound adsorption for adsorbing hydrogen sulfide and sulfur compounds, activated carbon 12 for ammonia adsorption for adsorption of ammonia and basic gas, and activated carbon 13 for chlorine adsorption for adsorption of chlorine and hydrochloric acid. Three types are used in layers.
[0025]
The general-purpose activated carbon 9 and the functional activated carbon 10 are used in such a manner that the life and replacement frequency become economically preferable from the relationship between the concentrations of the hydrocarbon compounds, hydrogen sulfide, ammonia, and chlorine in the biogas and the adsorption capacity of the activated carbon. The filling amount is determined.
[0026]
In a fuel cell power generation system having such a configuration, in particular, in the pretreatment device 1, biogas generated by methane fermentation from sewage, human waste, organic waste, or organic waste of food wastewater is subjected to a washing method, an alkali adsorption method, and the like. It is supplied to the biogas inlet 3 after adsorbing the concentration of impurities such as sulfur compounds, acids, and bases to several tens ppm, respectively, by any one of a method and an oxidation adsorption method.
[0027]
While the biogas passes through the general-purpose activated carbon 9 filled in the first container 5, hydrocarbon compounds such as a saturated hydrocarbon having 9 to 13 carbon atoms and a siloxane having 1 to 5 silicon atoms contained in the biogas are adsorbed. You. Note that sulfur compounds, acids, and basic impurities are also adsorbed to some extent.
[0028]
Next, while the biogas passes through the functional activated carbon 10 filled in the second container 7, hydrogen sulfide and sulfur compounds contained in the biogas are adsorbed by the activated carbon 11 for adsorbing sulfur compounds. Ammonia and basic gas are adsorbed by the activated carbon 12 for ammonia adsorption. Further, chlorine and hydrochloric acid are adsorbed by the activated carbon 13 for chlorine adsorption.
[0029]
At the outlet of the second container 7, the sulfur compound is reduced to 0.1 ppm or less, and the concentrations of ammonia and chlorine are reduced to 0.05 ppm or less, and supplied to the fuel cell power generator 2.
[0030]
As described above, in the present embodiment, among the impurities contained in the biogas, the hydrocarbon-based compounds that could not be adsorbed by the conventional pretreatment device even by using the water washing method, the alkali adsorption method, the oxidative adsorption method, or the like are used. It is adsorbed by the general-purpose activated carbon 9 in the first container 5 and further adsorbs impurities such as sulfur compounds, acids, and bases by the functional activated carbon 10 in the second container 7 to reduce the concentration thereof, and is used in a reformer or the like. Poisoning of the catalyst can be prevented, and the fuel cell power generation system can be operated stably for a long period of time.
[0031]
FIG. 2 is a schematic system diagram showing a second embodiment of the fuel cell power generation system according to the present invention. The same components as those of the first embodiment are denoted by the same reference numerals.
[0032]
In the fuel cell power generation system according to the present invention, when the general-purpose activated carbon 9 of the first container 5 has reached a predetermined replacement time during operation or when the replacement has to be performed for some reason, for example, performance degradation, etc. The first sub-container 16 is installed in parallel with the first container 5 so that the container 5 can be replaced, and the first container inlet stop valve 14 and the first container While the container outlet stop valve 15 is provided, a first sub-container inlet stop valve 17 and a first sub-container outlet stop valve 18 are also provided on the inlet side and the outlet side of the first sub-container 16, respectively. A first bypass pipe 19 is provided between the first container 5 and the first sub-container 16, and the first bypass pipe 19 has an inlet stop valve 20 for the first bypass container, an outlet stop valve 21 for the first bypass container, and a first bypass. Sub-container inlet stop valve 22, No. Is provided with a bypass sub container outlet stop valve 23.
[0033]
Further, in the fuel cell power generation system according to the present invention, similarly to the above, when the functional activated carbon 10 of the second container 7 comes to a predetermined replacement time during operation or for some reason such as performance deterioration, for example. When the replacement is required, the second container inlet stop valve 24 and the second container outlet stop are provided on the inlet side and the outlet side of the second container 7, respectively, so that the functional activated carbon 10 of the second container 7 can be replaced. A valve 25 is provided, and a second bypass pipe 27 provided with a second bypass valve 26 is provided in the second container 7.
[0034]
Next, an operation method of the fuel cell power generation system will be described.
[0035]
In the fuel cell power generation system having the above configuration, during normal operation, the first container 5 is in operation, and the first sub-container 16 is in standby. At this time, the first container inlet stop valve 14 and the first container outlet stop valve 15 are “open”, the first sub-container inlet stop valve 17 and the first sub-container outlet stop valve 18 are “closed”, The first stop valve 20 for the first bypass container, the outlet stop valve 21 for the first bypass container, the first stop valve 22 for the first bypass sub-container, and the first stop valve 23 for the first bypass sub-container of the 1 bypass pipe 19 are “closed”. "It has become.
[0036]
From this state, when the time for replacing the general-purpose activated carbon 4 of the first container 5 comes, the first sub-container inlet stop valve 17 and the first sub-container outlet valve 18 are opened, and the first container inlet stop valve 14 is opened. When the first container outlet stop valve 15 is closed, and the operation is switched from the first container 5 to the first sub-container 16 (note: the order is reversed), the general-purpose activated carbon 9 in the first container 5 becomes easy. Can be replaced.
[0037]
Also, in the second container 7, during the operation, when the time to replace the functional activated carbon 10 comes, the second bypass valve 26 of the second bypass pipe 27 is “opened”, and the second container inlet stop valve 24 and the second By closing the container outlet stop valve 25 and using the second bypass pipe 27 (note: the order is reversed), the functional activated carbon 10 of the second container 7 can be replaced.
[0038]
In this case, since the general-purpose activated carbon 9 in the first container 5 also has the ability to adsorb sulfur compounds, acids, and basic impurities, the bypass operation can be performed in a short period of time by replacing the functional activated carbon 10 in the second container 7. The catalyst of the reformer and the like of the fuel cell power generator 2 is not poisoned.
[0039]
When the first container 5 and the first sub-container 16 are used and the capacity of the general-purpose activated carbon 9 is sufficiently utilized, the first bypass pipe 19 is used to connect the first container 5 and the first sub-container 16 to each other. It may be operated by communicating. In this case, the first container inlet stop valve 14 is "open", the first container outlet stop valve 15 is "closed", the first sub-container inlet stop valve 17 is "closed", and the first sub-container outlet stop. The valve 18 is “open”, the first bypass container outlet stop valve 20 is “closed”, the first bypass container outlet stop valve 21 is “open”, the first bypass sub-container inlet stop valve 22 is “open”, The first bypass sub-container outlet stop valve 23 is closed.
[0040]
Thus, in the present embodiment, the first sub-container 16 is provided in parallel with the first container 5, the first bypass pipe 19 is provided between the first container 5 and the first sub-container 16, and the second container 7, the second bypass pipe 27 is also provided, so that the general-purpose activated carbon 9 and the functional activated carbon 10 having reduced adsorption capacity can be easily exchanged to maintain a high adsorption capacity.
[0041]
FIG. 3 is a schematic system diagram showing a third embodiment of the fuel cell power generation system according to the present invention. The same components as those of the first embodiment are denoted by the same reference numerals.
[0042]
The fuel cell power generation system according to the present embodiment is provided with a detector 28 and a shutoff valve 30 provided with a gas concentration calculator 29 between the second container 7 and the biogas outlet 8 of the pretreatment device 1. is there.
[0043]
Here, the detector 28 can detect the concentration of at least one or more of impurities that poison a catalyst such as a reformer of the fuel cell power generator 2, for example, hydrogen sulfide, ammonia, chlorine, oxygen, and the like. It has become.
[0044]
Further, the gas concentration calculator 29 inputs a preset allowable concentration signal to be compared with the actual gas concentration detected from the detector 28, and calculates a deviation when a deviation exceeds the allowable value. An alarm is issued and a command to close the shutoff valve 30 is issued.
[0045]
In the fuel cell power generation system having such a configuration, when the biogas flows to the detector 28 in a state where the impurities in the biogas are not sufficiently adsorbed by the functional activated carbon 10 of the second container 7, the biogas is generated here. For example, a gas concentration of any of hydrogen sulfide, ammonia, chlorine, and oxygen that poisons a catalyst of a reformer or the like of the apparatus 2 is detected.
[0046]
The detected gas concentration is supplied to a gas concentration calculator 29 and compared with a predetermined allowable value. When a deviation occurs, the gas concentration calculator 29 calculates an alarm signal and a shutoff command based on the deviation, issues an alarm, and closes the shutoff valve 30.
[0047]
As described above, in the present embodiment, the detector 28 and the shut-off valve 30 provided with the gas concentration calculator 29 are provided at the outlet side of the second container 7, and the biogas concentration detected by the detector 28 is calculated by the gas concentration calculation. When the allowable set value of the fuel cell 29 is exceeded, a warning signal is issued and a command to shut off the shutoff valve 30 is issued, so that the fuel cell power generator 2 can perform safe and stable operation.
[0048]
【The invention's effect】
As described above, according to the fuel cell power generation system and the operation method thereof according to the present invention, in the pretreatment device that adsorbs impurities serving as poisoning gas in biogas, general-purpose activated carbon and functional activated carbon are combined. Thereby, excellent impurity adsorption performance can be exhibited, and the operating cost can be reduced by improving the life of the activated carbon.
[0049]
In addition, since the operation is intermittently continued with the means for replacing the activated carbon during the operation, the operation rate can be improved.
[0050]
Further, since the means for detecting the gas concentration of the impurities in the biogas and the means for shutting off the gas flow when the concentration of the impurities is high are combined, safe and stable operation can be maintained.
[Brief description of the drawings]
FIG. 1 is a schematic system diagram showing a first embodiment of a fuel cell power generation system according to the present invention.
FIG. 2 is a schematic system diagram showing a second embodiment of the fuel cell power generation system according to the present invention.
FIG. 3 is a schematic system diagram showing a third embodiment of the fuel cell power generation system according to the present invention.
[Explanation of symbols]
Reference Signs List 1 Pretreatment device 2 Fuel cell power generator 3 Biogas 5 First container 7 Second container 8 Biogas outlet 9 General-purpose activated carbon 10 Functional activated carbon 11 Activated carbon for sulfur compound adsorption 12 Activated carbon for ammonia adsorption 13 Activated carbon for chlorine adsorption 14 First Container inlet stop valve 15 First container outlet stop valve 16 First sub-container 17 First sub-container inlet stop valve 18 First sub-container outlet stop valve 19 First bypass pipe 20 First bypass container inlet stop valve 21 Outlet stop valve for first bypass container 22 Inlet stop valve for first bypass sub-container 23 Outlet stop valve for first bypass sub-container 24 Inlet stop valve for second container 25 Outlet stop valve for second container 26 Second bypass valve 27 second bypass pipe 28 detector 29 gas concentration calculator 30 shut-off valve

Claims

A fuel cell comprising: a pretreatment device for treating impurities contained in biogas generated from organic waste; and a fuel cell power generation device for reforming a fuel treated by the pretreatment device and electrochemically generating power. In the power generation system, a fuel cell power generation system is characterized in that the pretreatment device has at least two or more containers connected with activated carbon in series.

Among the plurality of vessels connected in series, one is a first vessel filled with general-purpose activated carbon that adsorbs saturated hydrocarbons and their compounds contained in biogas, and the other is acids and bases contained in biogas. The fuel cell power generation system according to claim 1, further comprising a second container filled with a functional activated carbon that adsorbs at least one of sulfur.

3. The fuel cell power generation system according to claim 2, wherein the functional activated carbon filled in the second container is formed by layering activated carbon for sulfur compound adsorption, activated carbon for ammonia adsorption, and activated carbon for base adsorption.

The first container is divided into two units and arranged in parallel, and further includes a first bypass system, while the second container includes only one unit and includes a second bypass system. Item 3. The fuel cell power generation system according to Item 2.

A fuel cell comprising: a pretreatment device for treating impurities contained in biogas generated from organic waste; and a fuel cell power generation device for reforming a fuel treated by the pretreatment device and electrochemically generating power. In the power generation system, a detector that detects impurities contained in biogas between the pretreatment device and the fuel cell power generation device, and a shutoff valve that shuts off supply of biogas based on a signal detected from the detector A fuel cell power generation system comprising:

A shut-off valve is a gas concentration calculator that compares an actual detection signal that has detected impurities contained in biogas with a predetermined setting allowable signal and, when a deviation occurs, calculates a shut-off command based on the deviation. A fuel cell power generation system comprising:

Fuel cell power generation including a pretreatment device for treating impurities contained in biogas generated from organic waste, and a fuel cell power generation device for reforming fuel treated by the pretreatment device and electrochemically generating electricity In the system, when operating the pretreatment device comprising two first containers according to claim 4, one of the first containers is operated and the remaining first containers are kept on standby, and the first container in operation is operated. The method for operating a fuel cell power generation system, characterized in that when the activated carbon is replaced, the fuel cell power generation system is switched to the first container in a standby state and the operation is continued.

Fuel cell power generation including a pretreatment device for treating impurities contained in biogas generated from organic waste, and a fuel cell power generation device for reforming fuel treated by the pretreatment device and electrochemically generating electricity In the system, when operating the pretreatment device including the first container filled with general-purpose activated carbon and the second container filled with functional activated carbon, the functional activated carbon charged in the second container during operation is replaced. A method of operating the fuel cell power generation system, wherein the functional activated carbon in the second container is replaced by using a bypass system.