JP2004193013A

JP2004193013A - Fuel cell power generating device

Info

Publication number: JP2004193013A
Application number: JP2002361148A
Authority: JP
Inventors: Katsuya Wada; 克也和田; Hiromi Sasaki; 広美佐々木; Mototaka Kono; 元貴公野; Rinzo Miyoshi; 倫三三好
Original assignee: Toshiba International Fuel Cells Corp
Current assignee: Toshiba Energy Systems and Solutions Corp
Priority date: 2002-12-12
Filing date: 2002-12-12
Publication date: 2004-07-08

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generating device with a compact container for a small amount of heat radiation, heightened power generation efficiency, and a short starting period. <P>SOLUTION: The fuel cell power generating device has a carbon monoxide denaturation device and a carbon monoxide selective oxidation device. Metal monolith catalysts 26a, 26b are housed and fixed in a plurality of reactor bodies 27a, 27b respectively, the inside of respective body of reactors 27a, 27b are jointed and connected to each other, and a reformed fuel gas inlet nozzle 29 and a reformed fuel gas outlet nozzle 30 are arranged at the inside of both ends of the jointed reactor bodies 27a, 27b. Space areas 28, 31a, 31b for gas mixing are arranged between the metal monolith catalyst 26a and the metal monolith catalyst 26b in the jointed reactor bodies 27a, 27b, and between the reformed fuel gas inlet nozzle 29 as well as the reformed fuel gas outlet nozzle 30 and the metal monolith catalysts 26a, 26b. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、燃料改質系の改質器から生成された水素リッチな燃料に含まれている一酸化炭素（ＣＯ）を処理する一酸化炭素処理装置を備えた燃料電池発電装置に関する。
【０００２】
【従来の技術】
家庭用電源、自動車用動力源、商業用電源等として開発が進められている燃料電池発電装置では、原燃料として例えば炭化水素系燃料を用い、この炭化水素系燃料を水蒸気改質、部分酸化またはオートサーマル等の手法を用いて水素リッチな燃料改質ガスに改質させている。
【０００３】
このような手法を用いて生成される水素リッチな燃料改質ガスには、燃料電池アノード極の被毒成分である一酸化炭素（ＣＯ）が多く含まれており、燃料電池本体での発電の際、電池性能を低下させる要因になっている。
【０００４】
このため、燃料電池発電装置、例えば固体高分子型燃料電池発電装置では、一酸化炭素処理装置、具体的には一酸化炭素変成器および一酸化炭素選択酸化器を用い、一酸化炭素変成器で、触媒の下、一酸化炭素と水蒸気によるシフト反応により一酸化炭素濃度を１％以下に低減させ、さらに一酸化炭素選択酸化器で、触媒の下、空気等の酸化剤と選択酸化させて二酸化炭素を生成し、一酸化炭素濃度を数ｐｐｍのレベルまで低減させた後、燃料電池本体に供給し、ここで、触媒の下、水素リッチガスと酸素とを反応させ、電気を発生させている。
【０００５】
ところで、一酸化炭素変成器や一酸化炭素選択酸化器には、通常、触媒によって一酸化炭素濃度を低減させるため、球状または円柱状等の粒状触媒が用いられている。
【０００６】
しかし、これら粒状触媒は、その活性を支配する表面積を大きくすることに限界があり、必然的に反応容器自体の容積が大きくなる傾向にあった。
【０００７】
また、触媒担体として主に用いられるアルミナやシリカ等の無機材料は、伝熱特性が低いために昇温速度が遅く、このため起動時間が比較的長く要する等の不具合、不都合があった。
【０００８】
一方、自動車排ガス浄化用には、メタルハニカムに活性成分である触媒を担持させたメタルモノリス触媒が、開発されている。
【０００９】
しかし、このメタルモノリス触媒は、活性成分を担持できるメタルハニカム担体の長さ（燃料ガスの流れ方向の長さ）が、例えば１７０ｍｍ以上にも長くなり、触媒を均等に担持させることが難しくなる等の問題を抱えていた。
【００１０】
また、燃料電池発電装置用においても従来から使用している粒状の触媒に変えて、例えば、ハニカム構造、発泡体構造、あるいはコルゲート構造の担持体に触媒を担持させた発明として、例えば、特開２０００−２６４６０３号公報が開示されているが、その具体的な構造については述べられていない。
【００１１】
このため、燃料電池発電装置には、構造がコンパクトで、放熱量が少なく、起動特性の優れた一酸化炭素処理装置の実現が求められているものの、未だ、摸索の段階であるといえる。
【００１２】
【発明が解決しようとする課題】
ところで、例えば、家庭用に適用される燃料電池発電装置は、週単位、月単位の連続運転よりもむしろ、朝、起動させ、夜、停止させる等の１日単位での頻繁な起動と停止との繰り返し運転が想定されることから、起動特性がきわめて重要になっている。例えば、スイッチをＯＮすると、発電がすぐさま開始される等、対応の迅速化が切望されている。
【００１３】
また、産業用と較べて家庭用の燃料電池発電装置は、電気出力が小さいため、相対的に一酸化炭素変成器や一酸化炭素選択酸化器からの放熱量が大きくなっており、装置の発電効率を下げる原因となっている。この点からも反応器をコンパクトにして放熱量を少なくさせる一方、触媒の接触表面積をより広く確保させて発電効率を向上させることが必要とされる。
【００１４】
本発明は、このような背景技術に照らしてなされたもので、一酸化炭素変成器や一酸化炭素選択酸化器に代表される一酸化炭素処理装置の触媒表面積をより広く確保させるとともに、装置全体をコンパクトにして放熱量を少なくさせ、起動時間をより一層短くさせる燃料電池発電装置を提供することを目的とする。
【００１５】
【課題を解決するための手段】
本発明に係る燃料電池発電装置は、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、炭化水素系原燃料を水素リッチなガスに改質させる燃料改質系と、この燃料改質系からの燃料改質ガスに含まれる一酸化炭素の濃度を低減させる一酸化炭素変成器および一酸化炭素選択酸化器から構成される一酸化炭素処理系と、この一酸化炭素処理系から出た燃料改質ガス中の水素と空気中の酸素を電気化学的に反応させ、その際に発生する電力を取り出す発電系とを備えた燃料電池発電装置において、前記一酸化炭素変成器または一酸化炭素選択酸化器のうち、少なくとも一方の反応器胴体内に触媒活性成分を担持してなるメタルハニカムを配置した構造体を複数個接続して構成され、前記メタルハニカム間に空間領域が設けられているものである。
【００１６】
また、本発明に係る燃料電池発電装置は、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、炭化水素系原燃料を水素リッチなガスに改質させる燃料改質系と、この燃料改質系からの燃料改質ガスに含まれる一酸化炭素の濃度を低減させる一酸化炭素変成器および一酸化炭素選択酸化器から構成される一酸化炭素処理系と、この一酸化炭素処理系から出た燃料改質ガス中の水素と空気中の酸素を電気化学的に反応させ、その際に発生する電力を取り出す発電系とを備えた燃料電池発電装置において、一酸化炭素処理系は、第１段一酸化炭素変成器、第２段一酸化炭素変成器、一酸化炭素選択酸化器を燃料改質ガスの流れに沿って順に直列設置する構成にするとともに、前記第１段一酸化炭素変成器と前記第２段一酸化炭素変成器との間に一酸化炭素変成器用中間冷却器を備える一方、前記一酸化炭素選択酸化器の入口側と出口側とのそれぞれに一酸化炭素選択酸化器用前置冷却器と一酸化炭素選択酸化器用後置冷却器とを備えたものである。
【００１７】
また、本発明に係る燃料電池発電装置は、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１段一酸化炭素変成器、第２段一酸化炭素変成器および一酸化炭素選択酸化器のうち、少なくとも一つ以上の反応器胴体内には、セル密度の異なるメタルモノリス触媒を担持させた複数の担持体を収容させたものである。
【００１８】
また、本発明に係る燃料電池発電装置は、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段一酸化炭素変成器、第２段一酸化炭素変成器および一酸化炭素選択酸化器のうち、少なくとも一つ以上の反応器胴体内には、触媒活性成分の担持量の異なる複数のメタルモノリス触媒を収容させたものである。
【００１９】
また、本発明に係る燃料電池発電装置は、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、第１段一酸化炭素変成器、第２段一酸化炭素変成器および一酸化炭素選択酸化器のうち、少なくとも一つ以上の反応器胴体内には、複数のメタルモノリス触媒を収容させるとともに、前記複数のメタルモノリス触媒間、およびその入口側および出口側のそれぞれに空間領域を形成したものである。
【００２０】
また、本発明に係る燃料電池発電装置は、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、前記一酸化炭素処理系は、第１段一酸化炭素変成器、一酸化炭素変成器用中間冷却器、第２段一酸化炭素変成器を一つのブロック体として一体集合させ、一体集合させたブロック体に断熱材で被覆させる構成にしたものである。
【００２１】
また、本発明に係る燃料電池発電装置は、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、一酸化炭素変成器用中間冷却器は、第１段一酸化炭素変成器出口の改質ガスを冷却して第２段一酸化炭素変成器へ供給するとともに、改質用水蒸気を確保するため、燃料改質系に設けた蒸気発生器で加熱された水を、さらに加熱するものである。
【００２２】
また、本発明に係る燃料電池発電装置は、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、前記一酸化炭素処理系は、第１段一酸化炭素変成器、一酸化炭素変成器用中間冷却器、第２段一酸化炭素変成器、一酸化炭素選択酸化器用前置冷却器を一つのブロック体として一体集合させ、一体集合させたブロック体に断熱材で被覆させる構成にしたものである。
【００２３】
また、本発明に係る燃料電池発電装置は、上述の目的を達成するために、請求項９に記載したように、一酸化炭素選択酸化器前置冷却器を、第２段一酸化炭素変成器の出口改質ガスを冷却して一酸化炭素選択酸化器へ供給するとともに、改質用水蒸気を確保するため、蒸気発生器および一酸化炭素変成器用中間冷却器で加熱された水を、さらに加熱するものである。
【００２４】
また、本発明に係る燃料電池発電装置は、上述の目的を達成するために、請求項１０に記載したように、前記一酸化炭素処理系は、第１段一酸化炭素変成器、一酸化炭素変成器用中間冷却器、第２段一酸化炭素変成器、一酸化炭素選択酸化器用前置冷却器、一酸化炭素選択酸化器、一酸化炭素選択酸化器用後置冷却器を一つのブロック体として一体集合させ、一体集合させたブロック体に断熱材で被覆させる構成にするものである。
【００２５】
また、本発明に係る燃料電池発電装置は、上述の目的を達成するために、請求項１１に記載したように、一酸化炭素選択酸化器後置冷却器は、一酸化炭素選択酸化器出口の改質ガスを冷却して発電系の燃料電池アノードに供給し、改質用水蒸気を確保するため燃料改質系の蒸気発生器への供給水を予熱するものである。
【００２６】
【発明の実施の形態】
以下、本発明に係る燃料電池発電装置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。
【００２７】
図１は、本発明に係る燃料電池発電装置の実施形態を示す概略系統図である。
【００２８】
本実施形態に係る燃料電池発電装置は、原燃料Ｆを水素リッチな燃料ガスに改質させる燃料改質系１と、この燃料改質系１で改質された燃料改質ガスに含まれている一酸化炭素（ＣＯ）の濃度を低減化させる一酸化炭素処理系２と、この一酸化炭素処理系２からの燃料改質ガス中の水素と空気中の酸素を反応させ、その際、発生する電気を取り出す発電系３とで構成されている。
【００２９】
燃料改質系１は、脱硫器４、予熱器５、改質器６、蒸気発生器７、空気供給装置８を備え、起動運転時、脱硫器４で炭化水素系の原燃料Ｆの硫黄を脱硫後、その一部を起動用燃料供給系９を介して改質器６の起動用バーナ１０に供給し、ここで、空気供給装置８の起動用空気を混合させて燃焼ガスを生成し、改質器６内を加熱させる一方、脱硫後の残りの原燃料Ｆに水蒸気供給系１１からの水蒸気を加えて、予熱器５で加熱させた後、改質器６の改質触媒１２に供給し、ここで水蒸気改質させて水素リッチな燃料改質ガスを生成し、生成した燃料改質ガスは予熱器５に供給され、上述水蒸気を加えた燃料ガスと熱交換され、一酸化炭素処理系２に供給する構成になっている。
【００３０】
なお、改質器６内を加熱させた燃焼ガスは、排ガス系１３を介して蒸気発生器７に熱源として供給され、給水供給系１４からの水を水蒸気にした後、大気に排ガスとして放出される。
【００３１】
また、一酸化炭素処理系２は、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器用前置冷却器１８、一酸化炭素選択酸化器１９、一酸化炭素選択酸化器用後置冷却器２０を燃料改質ガスの流れに沿って順に直列設置し、予熱器５で原燃料Ｆと熱交換した改質器６の改質触媒１２からの水素リッチな燃料改質ガスのうち、燃料改質ガスに含まれる一酸化炭素を第１段一酸化炭素変成器１５の貴金属系または銅亜鉛系の触媒の下、一酸化炭素濃度を２％程度に低減させる。
【００３２】
第１段一酸化炭素変成器１５で一酸化炭素濃度を２％程度に低減された燃料改質ガスは、一酸化炭素変成器用中間冷却器１６で蒸気発生器７からの水蒸気で冷却され、温度約２００℃程度にして第２段一酸化炭素変成器１７に供給され、ここで貴金属系等の触媒の下、一酸化炭素濃度１％以下に低減される。
【００３３】
第２段一酸化炭素変成器１７で一酸化炭素濃度を１％以下に低減された燃料改質ガスは、例えばブロアで大気から吸込んだ空気が空気供給系２１を介して加えられ、一酸化炭素選択酸化器用前置冷却器１８で上述一酸化炭素変成器用中間冷却器１６から供給される水蒸気により温度１２０℃程度に冷却された後、一酸化炭素選択酸化器１９で一酸化炭素濃度が数ｐｐｍ程度に低減される。
【００３４】
一酸化炭素選択酸化器１９で一酸化炭素濃度を数ｐｐｍ程度に低減された燃料改質ガスは、例えば一般の市水または発電系３からポンプ３２を介して一酸化炭素選択酸化器用後置冷却器２０に供給される冷却水で冷却される。燃料改質ガスを冷却させた冷却水は、給水供給系１４を介して燃料改質系１の蒸気発生器７に供給される。
【００３５】
なお、第１段一酸化炭素変成器１５、第２段一酸化炭素変成器１７および一酸化炭素選択酸化器１９のそれぞれは、触媒の下、発熱反応により一酸化炭素濃度を低減させている。
【００３６】
また、発電系３は、燃料電池本体２３とアノードオフガス系２４とを備え、一酸化炭素処理系２からの一酸化炭素濃度を低減させた水素リッチなガスを燃料電池本体２３の燃料電池アノードへ供給し、燃料電池カソード（ともに図示せず）に流した空気中の酸素と化学反応させ、電気を発生させる一方、アノード極で未反応となった燃料改質ガス（アノードオフガス）を、アノードオフガス系２４を介して改質器６のメインバーナ２５に供給する。
【００３７】
そして、メインバーナ２５は、燃料電池本体３の発電が開始されると、燃料電池本体２３での未反応の燃料改質ガス（アノードオフガス）に、空気供給装置８からの空気が加えられ、燃焼ガスを生成する。なお、アノードオフガスによる燃焼が開始された後、起動用燃料供給系９を介して改質器６の起動用バーナ１０に供給されていた原燃料Ｆは停止される。
【００３８】
このように、本実施形態は、一酸化炭素処理系２を第１段一酸化炭素変成器１５、第２段一酸化炭素変成器１７および一酸化炭素選択酸化器１９に区分けし、各変成器１５、１７および選択酸化器１９に直列設置して構成するとともに、各変成器１５、１７および選択酸化器１９の中間および前後に一酸化炭素変成器用中間冷却器１６、一酸化炭素選択酸化器用前置冷却器１８、一酸化炭素選択酸化器用後置冷却器２０を設置し、各冷却器１６、１８、２０で燃料改質ガスを冷却させ、各変成器１５、１７および選択酸化器１９のそれぞれに収容する触媒が最も高い性能を発揮できるように反応器温度を維持させたので、燃料改質ガスに含まれている一酸化炭素の濃度をより一層低濃度化させることができる。
【００３９】
図２は、本発明に係る燃料電池発電装置の一酸化炭素処理装置２に適用する第１段一酸化炭素変成器１５、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器１９を構成する一体成型された反応器胴体とメタルモノリス触媒層の概念図である。
【００４０】
本実施形態に係る構造体は、ハニカム構造に形成され、ハニカム構造の壁面部に貴金属系触媒、例えば白金、ルテニウム等の触媒をコーティングした、いわゆるメタルモノリス触媒２６である。
【００４１】
このメタルモノリス触媒２６は、筒状の反応器胴体２７にハニカム構造の担持体を収容固定した後、ハニカム構造の壁面部に触媒活性成分が担持される。このとき、メタルモノリス触媒２６は軸方向の長さ（燃料改質ガスの流れ方向）は１７０ｍｍ以下、セル密度６００ｃｐｓｉ（セル数／平方インチ）以上においては、１００ｍｍ以下にしてある。
【００４２】
これは、ハニカム構造の担持体の壁面部に触媒活性成分をコーティングするとき、むらが出て均質に担持できなくなることを考慮したものである。
【００４３】
第１段一酸化炭素変成器１５、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器１９は、このように形成されたメタルモノリス触媒２６を、図３に示すように、円筒の両端を例えば溶接で接続し、長筒状の反応器胴体２７に収容固定された構造とする。具体的には、長筒状の反応器胴体２７は、予め別体で作製した複数のメタルハニカムに、第１反応器胴体２７ａおよび第２反応器胴体２７ｂを巻き付け、例えばロウ付けで一体固設した後、触媒活性成分を担持し、それぞれの胴体の端面を例えば溶接部Ｅの線に沿って溶接接続して一体の反応器胴体２７として形成する。なお、反応器胴体２７には、第１メタルモノリス触媒２６ａの入口側に、燃料改質ガス入口ノズル２９が、第２メタルモノリス触媒２６ｂの出口側に、燃料改質ガス出口ノズル３０がそれぞれ設けられている。
【００４４】
そして、第１反応器胴体２７ａに、例えばロウ付けで一体固設した第１メタルモノリス触媒２６ａと第２反応器胴体２７ｂに、例えばロウ付けで一体固設した第２メタルモノリス触媒２６ｂとの間に空間領域２８を形成するとともに、第１メタルモノリス触媒２６ａと第１反応器胴体２７ａの燃料改質ガス入口ノズル２９との間、および第２メタルモノリス触媒２６ｂと第２反応器胴体２７ｂの燃料改質ガス出口ノズル３０との間には、それぞれ空間領域３１ａ、３１ｂが形成される。
【００４５】
なお、空間領域３１ａ、３１ｂを反応器胴体２７に形成するのは、燃料改質ガスが各メタルモノリス触媒２６ａ、２６ｂを通過するとき、混合ができなくなるので、これらの領域３１ａ、３１ｂで燃料改質ガスを混合させて、流れに偏流をさせないようにするためである。
【００４６】
また、第１メタルモノリス触媒２６ａと第２メタルモノリス触媒２６ｂとの間に空間領域２８を形成したのは、第１反応器胴体２７ａと第２反応器胴体２７ｂとを溶接接続する際、溶接熱の第１メタルモノリス触媒２６ａ、第２メタルモノリス触媒２６ｂへの影響を与えないためでもある。
【００４７】
このように、本実施形態は、触媒を担持する担持体をハニカム構造にし、ハニカム構造の壁面部に触媒をコーティングする、いわゆる第１および第２メタルモノリス触媒２６ａ，２６ｂとし、触媒の表面積をより大きく確保させたので、燃料改質ガスを触媒で効率よく反応させることができ、従来の粒状またはペレット状の触媒に較べて触媒体積を少なくして熱容量を小さくすることができ、これに伴って反応器胴体２７から外部への放熱を少なくすることができるとともに起動に伴う昇温速度を速めることができ、起動時間をより一層短くすることができる。
【００４８】
図４は、本発明に係る燃料電池発電装置の一酸化炭素処理装置２に適用する第１段一酸化炭素変成器１５等の第２実施形態を示す概念図である。
【００４９】
第１段一酸化炭素変成器１５、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器１９を備える一酸化炭素処理装置２は、反応器胴体２７にメタルモノリス触媒２６を収容固定させる際、空間領域２８、３１ａ、３１ｂを形成して第１メタルモノリス触媒２６ａと第２メタルモノリス触媒２６ｂとの複数に区分けして挿着する。
【００５０】
この場合、第１メタルモノリス触媒２６ａと第２メタルモノリス触媒２６ｂとは、ハニカム構造の担持体のセル密度またはコーティングする触媒の担持量を互いに異ならしめている。
【００５１】
従来、一酸化炭素処理装置２は、燃料改質ガスを触媒に反応させる際、入口側で急激な触媒反応が起るため、触媒の温度が急上昇し、長年の使用の結果、性能劣化、損耗の要因になっていた。
【００５２】
本実施形態は、このような点を考慮したもので、第１メタルモノリス触媒２６ａと第２メタルモノリス触媒２６ｂの担持体としてのハニカムのセル密度またはハニカムにコーティングする触媒の担持量を変化させたもので、例えば第１メタルモノリス触媒２６ａの触媒反応を第２メタルモノリス触媒２６ｂに較べて緩やかにし、触媒入口側の急激な温度上昇を抑制したものである。
【００５３】
このように、本実施形態は、一酸化炭素処理装置２の反応器胴体２７に収容する第１メタルモノリス触媒２６ａと第２メタルモノリス触媒２６ｂの担持体としてのハニカムのセル密度またはハニカムにコーティングする触媒の担持量を異ならしめて触媒反応の際、温度上昇を抑制する構成にしたので、一酸化炭素処理装置２に寿命の長い安定した触媒反応を行わせることができる。なお、選択酸化反応の場合、一酸化炭素選択酸化器１９は、触媒を低温にしておくと、一酸化炭素反応率が高くなるので、比較的少ない酸化剤で一酸化炭素を酸化することができ、ひいては酸化剤投入量を少なくして燃料電池効率を向上させることができる点で有効である。
【００５４】
図５は、本発明に係る燃料電池発電装置の一酸化炭素処理装置の第１実施形態を示す概念図である。
【００５５】
本実施形態に係る一酸化炭素処理装置２は、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器用前置冷却器１８、一酸化炭素選択酸化器１９、一酸化炭素選択酸化器用後置冷却器２０のうち、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７を適用対象にしている。
【００５６】
本実施形態に係る一酸化炭素処理装置２は、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７を一つのブロック体３２ａとして一体集合させ、一体集合させたブロック体３２ａに、例えば分割したセラミックス等の断熱材３３で被覆させたものである。なお、破線で示す符号ＦＧは、燃料改質ガスの流れを示している。
【００５７】
このように、本実施形態は、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７を一つのブロック体３２ａとして一体集合させ、一体集合させたブロック体３２ａに断熱材３３で被覆させたので、一酸化炭素処理装置２の設置面積をより一層少なくさせることができ、各機器から発生する発熱反応に伴う外部への放熱をより一層少なくさせることができる。
【００５８】
図６は、本発明に係る燃料電池発電装置の一酸化炭素処理装置の第２実施形態を示す概念図である。
【００５９】
本実施形態に係る一酸化炭素処理装置２は、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器用前置冷却器１８、一酸化炭素選択酸化器１９、一酸化炭素選択酸化器用後置冷却器２０のうち、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器用前置冷却器１８を適用対象にしている。
【００６０】
本実施形態に係る一酸化炭素処理装置２は、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器用前置冷却器１８を一つのブロック体３２ｂとして一体集合させ、一体集合させたブロック体３２ｂに、例えば分割したセラミックス等の断熱材３３で被覆させたものである。なお、破線で示す符号ＦＧは、燃料改質ガスの流れを示している。
【００６１】
このように、本実施形態は、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器用前置冷却器１８を一つのブロック体３２ｂとして一体集合させ、一体集合させたブロック体３２ｂに断熱材３３で被覆させたので、一酸化炭素処理装置２の設置面積をより一層少なくさせることができ、各機器から発生する発熱反応に伴う外部への放熱をより一層少なくさせることができる。
【００６２】
図７は、本発明に係る燃料電池発電装置の一酸化炭素処理装置の第３実施形態を示す概念図である。
【００６３】
本実施形態に係る一酸化炭素処理装置２は、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器用前置冷却器１８、一酸化炭素選択酸化器１９、一酸化炭素選択酸化器用後置冷却器２０で構成されたすべての機器を適用対象としている。
【００６４】
本実施形態に係る一酸化炭素処理装置２は、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器用前置冷却器１８、一酸化炭素選択酸化器１９、一酸化炭素選択酸化器用後置冷却器２０を一つのブロック体３２ｃとして一体集合させ、一体集合させたブロック体３２ｃに、例えば分割したセラミックス等の断熱材３３で被覆させたものである。なお、破線で示す符号ＦＧは、燃料改質ガスの流れを示している。
【００６５】
このように、本実施形態は、第１段一酸化炭素変成器１５、一酸化炭素変成器用中間冷却器１６、第２段一酸化炭素変成器１７、一酸化炭素選択酸化器用前置冷却器１８、一酸化炭素選択酸化器１９、一酸化炭素選択酸化器用後置冷却器２０を一つのブロック体３２ａとして一体集合させ、一体集合させたブロック体３２ｃに断熱材３３で被覆させたので、一酸化炭素処理装置２の設置面積をより一層少なくさせることができ、各機器から発生する発熱反応に伴う外部への放熱をより一層少なくさせることができる。
【００６６】
【発明の効果】
以上の説明のとおり、本発明に係る燃料電池発電装置は、一酸化炭素処理装置を、第１段一酸化炭素変成器、一酸化炭素変成器用中間冷却器、第２段一酸化炭素変成器、一酸化炭素選択酸化器用前置冷却器、一酸化炭素選択酸化器、一酸化炭素選択酸化器用後置冷却器で構成し、第１段一酸化炭素変成器、第２段一酸化炭素変成器、一酸化炭素選択酸化器のそれぞれに収容する少なくとも一つ以上のメタルモノリス触媒をハニカム構造の担持体として構成するとともに、各担持体のセル密度や触媒担持量を異ならしめたので、燃料改質ガスとの反応温度を低く抑えて反応温度の急激な上昇を抑制することができると同時に、燃料改質ガスとの反応面積をより広く確保することができるため触媒容積を小さくすることができる。
【００６７】
また、各機器を一体集合させ、一体集合させた一酸化炭素処理装置を断熱材で被覆させたので、設置面積をより一層少なくさせることができ、一酸化炭素処理装置の触媒の反熱反応に伴う熱の外部への放熱がより一層少なくなるので、燃料電池の発電効率を高めることができるとともに、起動時間も短くすることができる。
【図面の簡単な説明】
【図１】本発明に係る燃料電池発電装置の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装置の一酸化炭素処理装置のうち、容器にメタルモノリス触媒を収容したことを示す概念図。
【図３】本発明に係る燃料電池発電装置の一酸化炭素処理装置に含まれる反応器の第１実施形態を示す概念図。
【図４】本発明に係る燃料電池発電装置の一酸化炭素処理装置に含まれる反応器の第２実施形態を示す概念図。
【図５】本発明に係る燃料電池発電装置の一酸化炭素処理装置の第１実施形態を示す概念図。
【図６】本発明に係る燃料電池発電装置の一酸化炭素処理装置の第２実施形態を示す概念図。
【図７】本発明に係る燃料電池発電装置の一酸化炭素処理装置の第３実施形態を示す概念図。
【符号の説明】
１燃料改質系
２一酸化炭素処理系
３発電系
４脱硫器
５予熱器
６改質器
７蒸気発生器
８空気供給装置
９起動用燃料供給系
１０起動用バーナ
１１水蒸気供給系
１２改質触媒
１３排ガス系
１４給水供給系
１５第１段一酸化炭素変成器
１６一酸化炭素変成器用中間冷却器
１７第２段一酸化炭素変成器
１８一酸化炭素選択酸化器用前置冷却器
１９一酸化炭素選択酸化器
２０一酸化炭素選択酸化器用後置冷却器
２１空気供給系
２２ポンプ
２３燃料電池本体
２４アノードオフガス系
２５メインバーナ
２６メタルモノリス触媒
２６ａ第１メタルモノリス触媒
２６ｂ第２メタルモノリス触媒
２７反応器胴体
２７ａ第１反応器胴体
２７ｂ第２反応器胴体
２８空間領域
２９燃料改質ガス入口ノズル
３０燃料改質ガス出口ノズル
３１ａ，３１ｂ空間領域
３２ａ，３２ｂ，３２ｃブロック体
３３断熱材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell power generator including a carbon monoxide processing device that processes carbon monoxide (CO) contained in a hydrogen-rich fuel generated from a reformer of a fuel reforming system.
[0002]
[Prior art]
In a fuel cell power generator which is being developed as a household power source, a vehicle power source, a commercial power source, etc., for example, a hydrocarbon fuel is used as a raw fuel, and the hydrocarbon fuel is subjected to steam reforming, partial oxidation or The fuel is reformed into a hydrogen-rich fuel reformed gas using a method such as autothermal.
[0003]
The hydrogen-rich fuel reformed gas generated by such a method contains a large amount of carbon monoxide (CO), which is a poisoning component of the anode of the fuel cell, and the power generation in the fuel cell itself is performed. In this case, it is a factor that lowers battery performance.
[0004]
For this reason, a fuel cell power generator, for example, a polymer electrolyte fuel cell power generator, uses a carbon monoxide treatment device, specifically, a carbon monoxide converter and a carbon monoxide selective oxidizer, and uses a carbon monoxide converter. Under a catalyst, the carbon monoxide concentration is reduced to 1% or less by a shift reaction with carbon monoxide and water vapor, and the carbon dioxide is selectively oxidized with an oxidizing agent such as air under a catalyst in a carbon monoxide selective oxidizer. After generating carbon and reducing the concentration of carbon monoxide to a level of several ppm, it is supplied to the fuel cell main body, where a hydrogen-rich gas and oxygen are reacted under a catalyst to generate electricity.
[0005]
Meanwhile, in the carbon monoxide converter and the carbon monoxide selective oxidizer, a granular catalyst such as a spherical or columnar catalyst is generally used in order to reduce the concentration of carbon monoxide by a catalyst.
[0006]
However, these granular catalysts have a limit in increasing the surface area that controls their activity, and the volume of the reaction vessel itself tends to increase inevitably.
[0007]
Further, inorganic materials such as alumina and silica, which are mainly used as catalyst carriers, have low heat transfer characteristics and therefore have a low temperature rising rate, and thus have disadvantages and disadvantages such as a relatively long startup time.
[0008]
On the other hand, for automotive exhaust gas purification, a metal monolith catalyst in which a catalyst as an active component is supported on a metal honeycomb has been developed.
[0009]
However, in this metal monolith catalyst, the length of the metal honeycomb carrier capable of supporting the active component (the length in the flow direction of the fuel gas) is, for example, 170 mm or more, which makes it difficult to uniformly support the catalyst. Had the problem.
[0010]
Further, in the fuel cell power generation device, instead of the granular catalyst conventionally used, for example, as an invention in which the catalyst is carried on a carrier having a honeycomb structure, a foam structure, or a corrugated structure, for example, JP JP-A-2000-264603 is disclosed, but no specific structure is described.
[0011]
For this reason, a fuel cell power generator is required to realize a carbon monoxide treatment apparatus having a compact structure, a small amount of heat radiation, and excellent start-up characteristics.
[0012]
[Problems to be solved by the invention]
By the way, for example, a fuel cell power generation device applied for home use is not a continuous operation on a weekly or monthly basis, but is frequently started and stopped on a daily basis such as in the morning, started, at night, or stopped. Since the repeated operation is assumed, the start-up characteristic is extremely important. For example, when a switch is turned on, power generation is started immediately, and there is a strong demand for quick response.
[0013]
In addition, compared with industrial fuel cells, household fuel cell power generators have a smaller electric output, so the amount of heat released from the carbon monoxide converter and the carbon monoxide selective oxidizer is relatively large. It causes the efficiency to decrease. From this point as well, it is necessary to improve the power generation efficiency by securing a wider contact surface area of the catalyst while reducing the heat release amount by making the reactor compact.
[0014]
The present invention has been made in view of such background art, and has a catalyst surface area of a carbon monoxide treatment device represented by a carbon monoxide converter and a carbon monoxide selective oxidizer that is assured to be wider, and the entire device has been improved. It is an object of the present invention to provide a fuel cell power generation device which is compact in size, reduces the amount of heat radiation, and further shortens the startup time.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, a fuel cell power generation apparatus according to the present invention includes a fuel reforming system for reforming a hydrocarbon-based raw fuel into a hydrogen-rich gas, A carbon monoxide treatment system consisting of a carbon monoxide converter and a carbon monoxide selective oxidizer that reduces the concentration of carbon monoxide contained in the fuel reformed gas from the reforming system, Wherein the hydrogen in the discharged fuel reformed gas and the oxygen in the air electrochemically react with each other, and a power generation system for taking out the electric power generated at that time. Among the carbon oxide selective oxidizers, at least one of the reactor bodies is provided with a plurality of structures each having a metal honeycomb carrying a catalytically active component disposed therein, and a plurality of structures are connected, and a space region is provided between the metal honeycombs. What A.
[0016]
Further, in order to achieve the above object, the fuel cell power generation device according to the present invention, as described in claim 2, a fuel reforming system for reforming a hydrocarbon-based raw fuel into a hydrogen-rich gas, A carbon monoxide treatment system comprising a carbon monoxide converter and a carbon monoxide selective oxidizer for reducing the concentration of carbon monoxide contained in the fuel reformed gas from the fuel reforming system; The hydrogen in the fuel reformed gas discharged from the system electrochemically reacts the oxygen in the air with the oxygen in the air, and a power generation system that extracts the electric power generated at that time. , A first-stage carbon monoxide converter, a second-stage carbon monoxide converter, and a carbon monoxide selective oxidizer are sequentially arranged in series along the flow of the fuel reforming gas. A carbon converter and the second stage carbon monoxide converter While an intermediate cooler for a carbon monoxide converter is provided, while a pre-cooler for a carbon monoxide selective oxidizer and a post-cooler for a carbon monoxide selective oxidizer are respectively provided on an inlet side and an outlet side of the carbon monoxide selective oxidizer. And a container.
[0017]
According to a third aspect of the present invention, a fuel cell power generator according to the present invention includes a first-stage carbon monoxide converter, a second-stage carbon monoxide converter, Among the carbon selective oxidizers, at least one or more reactor bodies accommodate a plurality of carriers carrying metal monolith catalysts having different cell densities.
[0018]
Further, in order to achieve the above object, the fuel cell power generator according to the present invention has a first-stage carbon monoxide converter, a second-stage carbon monoxide converter and Among the carbon selective oxidizers, at least one or more reactor bodies accommodate a plurality of metal monolith catalysts having different amounts of catalytically active components.
[0019]
According to a fifth aspect of the present invention, a fuel cell power generator according to the present invention includes a first-stage carbon monoxide converter, a second-stage carbon monoxide converter, and a fuel cell. Among the carbon selective oxidizers, at least one or more reactor bodies accommodate a plurality of metal monolith catalysts, and a space region is provided between the plurality of metal monolith catalysts, and on the inlet side and the outlet side, respectively. It was formed.
[0020]
Further, in order to achieve the above object, the fuel cell power generation device according to the present invention, as described in claim 6, wherein the carbon monoxide treatment system comprises a first-stage carbon monoxide converter, a carbon monoxide converter. An intercooler for a transformer and a second-stage carbon monoxide transformer are integrally assembled as one block body, and the integrally assembled block body is covered with a heat insulating material.
[0021]
Further, in order to achieve the above object, the fuel cell power generator according to the present invention is configured such that the intercooler for the carbon monoxide converter is provided at the outlet of the first stage carbon monoxide converter. Cooling the reformed gas and supplying it to the second-stage carbon monoxide converter, and further heating the water heated by the steam generator provided in the fuel reforming system to secure the reforming steam It is.
[0022]
Further, in order to achieve the above object, in the fuel cell power generator according to the present invention, as described in claim 8, the carbon monoxide treatment system includes a first-stage carbon monoxide converter, a carbon monoxide converter, The intercooler for the transformer, the second-stage carbon monoxide converter, and the pre-cooler for the carbon monoxide selective oxidizer are integrally assembled as one block body, and the integrally assembled block body is covered with a heat insulating material. Things.
[0023]
Further, in order to achieve the above object, the fuel cell power generator according to the present invention includes a carbon monoxide selective oxidizer pre-cooler, a second-stage carbon monoxide converter, as described in claim 9. The outlet reformed gas is cooled and supplied to the carbon monoxide selective oxidizer, and the water heated by the steam generator and the intercooler for the carbon monoxide converter is further heated to secure reforming steam. Is what you do.
[0024]
Further, in order to achieve the above object, the fuel cell power generation device according to the present invention, as described in claim 10, wherein the carbon monoxide treatment system comprises a first-stage carbon monoxide converter, a carbon monoxide converter. Intermediate cooler for transformer, second stage carbon monoxide transformer, pre-cooler for carbon monoxide selective oxidizer, carbon monoxide selective oxidizer, post-cooler for carbon monoxide selective oxidizer as one block unit It is configured to be assembled, and the block body that is integrated is covered with a heat insulating material.
[0025]
Further, in order to achieve the above object, the fuel cell power generator according to the present invention is configured such that the carbon monoxide selective oxidizer post-cooler is provided with a carbon monoxide selective oxidizer outlet. The reformed gas is cooled and supplied to the fuel cell anode of the power generation system, and the water supplied to the steam generator of the fuel reforming system is preheated in order to secure the steam for reforming.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a fuel cell power generator according to the present invention will be described with reference to the drawings and reference numerals attached to the drawings.
[0027]
FIG. 1 is a schematic system diagram showing an embodiment of a fuel cell power generator according to the present invention.
[0028]
The fuel cell power generation device according to the present embodiment includes a fuel reforming system 1 that reforms a raw fuel F into a hydrogen-rich fuel gas, and a fuel reforming gas that is reformed by the fuel reforming system 1. A carbon monoxide treatment system 2 for reducing the concentration of carbon monoxide (CO), and reacting the hydrogen in the fuel reformed gas from the carbon monoxide treatment system 2 with the oxygen in the air. And a power generation system 3 for extracting electricity.
[0029]
The fuel reforming system 1 includes a desulfurizer 4, a preheater 5, a reformer 6, a steam generator 7, and an air supply device 8. At the start-up operation, the desulfurizer 4 removes the sulfur of the hydrocarbon-based raw fuel F. After the desulfurization, a part of the gas is supplied to a starter burner 10 of the reformer 6 via a starter fuel supply system 9, where the starter air of the air supply device 8 is mixed to generate a combustion gas, While the inside of the reformer 6 is heated, the steam from the steam supply system 11 is added to the remaining raw fuel F after desulfurization, heated by the preheater 5, and then supplied to the reforming catalyst 12 of the reformer 6. Then, steam reforming is performed to generate a hydrogen-rich fuel reformed gas, and the generated fuel reformed gas is supplied to the preheater 5, where the fuel reformed gas undergoes heat exchange with the above-described fuel gas to which steam has been added, and the carbon monoxide treatment It is configured to supply to the system 2.
[0030]
The combustion gas that has heated the inside of the reformer 6 is supplied to the steam generator 7 via the exhaust gas system 13 as a heat source, and after the water from the water supply system 14 is turned into steam, is discharged to the atmosphere as exhaust gas. You.
[0031]
The carbon monoxide treatment system 2 includes a first-stage carbon monoxide converter 15, an intermediate cooler 16 for the carbon monoxide converter, a second-stage carbon monoxide converter 17, and a pre-cooler for the carbon monoxide selective oxidizer. 18, a carbon monoxide selective oxidizer 19, and a post-cooler 20 for the carbon monoxide selective oxidizer are sequentially installed in series along the flow of the fuel reforming gas, and the preheater 5 exchanges heat with the raw fuel F. Among the hydrogen-rich fuel reformed gas from the reforming catalyst 12 of No. 6, the carbon monoxide contained in the fuel reformed gas is converted under the noble metal-based or copper-zinc-based catalyst of the first-stage carbon monoxide converter 15 The concentration of carbon monoxide is reduced to about 2%.
[0032]
The fuel reformed gas whose carbon monoxide concentration has been reduced to about 2% in the first-stage carbon monoxide converter 15 is cooled by steam from the steam generator 7 in the intercooler 16 for carbon monoxide converter, and the temperature is reduced. At about 200 ° C., the mixture is supplied to the second-stage carbon monoxide converter 17 where the concentration of carbon monoxide is reduced to 1% or less under a catalyst such as a noble metal.
[0033]
The fuel reformed gas whose carbon monoxide concentration has been reduced to 1% or less in the second-stage carbon monoxide converter 17 is, for example, air sucked from the atmosphere by a blower added through an air supply system 21 to obtain carbon monoxide. After being cooled to a temperature of about 120 ° C. by the steam supplied from the intercooler 16 for the carbon monoxide converter in the pre-cooler 18 for the selective oxidizer, the carbon monoxide concentration in the selective oxidizer 19 is several ppm. To a degree.
[0034]
The fuel reformed gas whose carbon monoxide concentration has been reduced to about several ppm by the carbon monoxide selective oxidizer 19 is, for example, post-cooled for the carbon monoxide selective oxidizer from general city water or the power generation system 3 via the pump 32. It is cooled by cooling water supplied to the vessel 20. The cooling water that has cooled the fuel reformed gas is supplied to the steam generator 7 of the fuel reforming system 1 via the feedwater supply system 14.
[0035]
Each of the first-stage carbon monoxide converter 15, the second-stage carbon monoxide converter 17, and the carbon monoxide selective oxidizer 19 reduces the concentration of carbon monoxide by an exothermic reaction under a catalyst.
[0036]
The power generation system 3 includes a fuel cell main body 23 and an anode off-gas system 24, and supplies a hydrogen-rich gas from the carbon monoxide processing system 2 with a reduced carbon monoxide concentration to the fuel cell anode of the fuel cell main body 23. The fuel reformed gas (anode off gas) that has been supplied and chemically reacted with oxygen in the air flowing to a fuel cell cathode (both not shown) to generate electricity, while the unreacted fuel reformed gas (anode off gas) at the anode electrode is supplied to the anode off gas It is supplied to the main burner 25 of the reformer 6 via the system 24.
[0037]
Then, when the power generation of the fuel cell main body 3 is started, the main burner 25 adds air from the air supply device 8 to the unreacted fuel reformed gas (anode off gas) in the fuel cell main body 23 and burns. Generate gas. After the combustion by the anode off-gas is started, the raw fuel F supplied to the starting burner 10 of the reformer 6 via the starting fuel supply system 9 is stopped.
[0038]
As described above, in the present embodiment, the carbon monoxide treatment system 2 is divided into the first-stage carbon monoxide converter 15, the second-stage carbon monoxide converter 17, and the carbon monoxide selective oxidizer 19, 15 and 17 and a selective oxidizer 19, and an intermediate cooler 16 for the carbon monoxide converter and a front and a rear for the carbon monoxide selective oxidizer are provided before and after each of the transformers 15 and 17 and the selective oxidizer 19. The pre-cooler 18 and the post-cooler 20 for the carbon monoxide selective oxidizer are installed, and the fuel reformed gas is cooled by the respective coolers 16, 18, and 20, and each of the transformers 15, 17 and the selective oxidizer 19 Since the reactor temperature was maintained so that the catalyst contained in the fuel cell can exhibit the highest performance, the concentration of carbon monoxide contained in the fuel reformed gas can be further reduced.
[0039]
FIG. 2 shows a first-stage carbon monoxide converter 15, a second-stage carbon monoxide converter 17, and a carbon monoxide selective oxidizer 19 applied to the carbon monoxide treatment device 2 of the fuel cell power generation device according to the present invention. It is a conceptual diagram of the integrally formed reactor body and metal monolith catalyst layer which constitute.
[0040]
The structure according to the present embodiment is a so-called metal monolith catalyst 26 that is formed in a honeycomb structure and has a wall surface portion of the honeycomb structure coated with a noble metal-based catalyst, for example, a catalyst such as platinum or ruthenium.
[0041]
In the metal monolith catalyst 26, after a carrier having a honeycomb structure is accommodated and fixed in a tubular reactor body 27, a catalytically active component is carried on a wall surface portion of the honeycomb structure. At this time, the length of the metal monolith catalyst 26 in the axial direction (flow direction of the fuel reformed gas) is 170 mm or less, and is 100 mm or less when the cell density is 600 cpsi (cell number / square inch) or more.
[0042]
This is in consideration of the fact that when the catalytically active component is coated on the wall surface of the carrier having the honeycomb structure, unevenness occurs and the carrier cannot be uniformly supported.
[0043]
The first-stage carbon monoxide converter 15, the second-stage carbon monoxide converter 17, and the carbon monoxide selective oxidizer 19, as shown in FIG. Both ends are connected, for example, by welding, so that the structure is accommodated and fixed in the long tubular reactor body 27. Specifically, the first tubular body 27a and the second tubular body 27b are wound around a plurality of metal honeycombs separately manufactured in advance, and the long tubular reactor body 27 is integrally fixed by, for example, brazing. After that, the catalytically active component is supported, and the end faces of the respective bodies are welded and connected, for example, along the line of the welded portion E to form an integral reactor body 27. The reactor body 27 is provided with a fuel reformed gas inlet nozzle 29 on the inlet side of the first metal monolith catalyst 26a, and a fuel reformed gas outlet nozzle 30 on the outlet side of the second metal monolith catalyst 26b. Have been.
[0044]
Then, a first metal monolith catalyst 26a integrally fixed to the first reactor body 27a by, for example, brazing, and a second metal monolith catalyst 26b integrally fixed to the second reactor body 27b, for example, by brazing. A space region 28 is formed between the first metal monolith catalyst 26a and the fuel reforming gas inlet nozzle 29 of the first reactor body 27a, and the fuel between the second metal monolith catalyst 26b and the second reactor body 27b. Space regions 31a and 31b are formed between the reformed gas outlet nozzle 30 and the reformed gas outlet nozzle 30, respectively.
[0045]
The space regions 31a and 31b are formed in the reactor body 27 because the fuel reforming gas cannot mix when passing through the metal monolith catalysts 26a and 26b, so that the fuel reforming gas is formed in these regions 31a and 31b. This is for mixing the raw gas to prevent the flow from drifting.
[0046]
Further, the space region 28 is formed between the first metal monolith catalyst 26a and the second metal monolith catalyst 26b because the first reactor body 27a and the second reactor body 27b are welded by welding heat. This does not affect the first metal monolith catalyst 26a and the second metal monolith catalyst 26b.
[0047]
As described above, in the present embodiment, the so-called first and second metal monolith catalysts 26a and 26b, in which the carrier for supporting the catalyst has a honeycomb structure and the catalyst is coated on the wall surface of the honeycomb structure, and the surface area of the catalyst is increased. As a result, the fuel reformed gas can be efficiently reacted with the catalyst, and the heat capacity can be reduced by reducing the catalyst volume as compared with a conventional granular or pelletized catalyst. The heat radiation from the reactor body 27 to the outside can be reduced, and the rate of temperature rise upon startup can be increased, so that the startup time can be further shortened.
[0048]
FIG. 4 is a conceptual diagram showing a second embodiment of the first-stage carbon monoxide converter 15 and the like applied to the carbon monoxide treatment device 2 of the fuel cell power generator according to the present invention.
[0049]
The carbon monoxide processing apparatus 2 including the first-stage carbon monoxide converter 15, the second-stage carbon monoxide converter 17, and the carbon monoxide selective oxidizer 19 causes the reactor body 27 to house and fix the metal monolith catalyst 26. At this time, the space regions 28, 31a, 31b are formed, and the first metal monolith catalyst 26a and the second metal monolith catalyst 26b are divided and inserted into a plurality.
[0050]
In this case, the first metal monolith catalyst 26a and the second metal monolith catalyst 26b differ from each other in the cell density of the carrier having the honeycomb structure or the amount of the catalyst to be coated.
[0051]
Conventionally, in the carbon monoxide treatment device 2, when the fuel reformed gas reacts with the catalyst, a sharp catalytic reaction occurs on the inlet side, so that the temperature of the catalyst rises rapidly, and as a result of long-term use, performance degradation and wear are caused. Was a factor.
[0052]
In the present embodiment, in consideration of such a point, the cell density of the honeycomb as the carrier of the first metal monolith catalyst 26a and the second metal monolith catalyst 26b or the amount of the catalyst coated on the honeycomb is changed. For example, the catalytic reaction of the first metal monolith catalyst 26a is made slower than that of the second metal monolith catalyst 26b, and a rapid temperature rise on the catalyst inlet side is suppressed.
[0053]
As described above, in the present embodiment, the cell density or the honeycomb of the honeycomb as the carrier of the first metal monolith catalyst 26a and the second metal monolith catalyst 26b housed in the reactor body 27 of the carbon monoxide treatment apparatus 2 is coated. Since the temperature rise is suppressed during the catalytic reaction by changing the amount of the catalyst carried, the carbon monoxide treatment device 2 can perform a stable catalytic reaction with a long life. In the case of the selective oxidation reaction, the carbon monoxide selective oxidizer 19 can oxidize carbon monoxide with a relatively small amount of oxidizing agent because the reaction rate of carbon monoxide increases when the temperature of the catalyst is kept low. This is effective in that the fuel cell efficiency can be improved by reducing the amount of the oxidizing agent to be introduced.
[0054]
FIG. 5 is a conceptual diagram showing a first embodiment of a carbon monoxide treatment device according to the present invention.
[0055]
The carbon monoxide processing apparatus 2 according to the present embodiment includes a first-stage carbon monoxide converter 15, an intercooler 16 for a carbon monoxide converter, a second-stage carbon monoxide converter 17, and a front-end for a carbon monoxide selective oxidizer. Among the pre-cooler 18, the carbon monoxide selective oxidizer 19, and the post-cooler 20 for the carbon monoxide selective oxidizer, the first-stage carbon monoxide converter 15, the intermediate cooler 16 for the carbon monoxide converter, and the second stage The target is the carbon monoxide converter 17.
[0056]
The carbon monoxide processing apparatus 2 according to the present embodiment includes a first-stage carbon monoxide converter 15, an intercooler 16 for a carbon monoxide converter, and a second-stage carbon monoxide converter 17 as one block body 32a. The block body 32a that has been assembled and integrated is covered with a heat insulating material 33 such as a divided ceramic, for example. The symbol FG indicated by a broken line indicates the flow of the fuel reformed gas.
[0057]
As described above, in the present embodiment, the first-stage carbon monoxide converter 15, the intercooler 16 for the carbon monoxide converter, and the second-stage carbon monoxide converter 17 are integrally assembled as one block body 32a. Since the assembled block body 32a is covered with the heat insulating material 33, the installation area of the carbon monoxide treatment device 2 can be further reduced, and the heat radiation to the outside accompanying the exothermic reaction generated from each device is further improved. Can be reduced.
[0058]
FIG. 6 is a conceptual diagram showing a second embodiment of the carbon monoxide treatment device according to the present invention.
[0059]
The carbon monoxide processing apparatus 2 according to the present embodiment includes a first-stage carbon monoxide converter 15, an intercooler 16 for a carbon monoxide converter, a second-stage carbon monoxide converter 17, and a front-end for a carbon monoxide selective oxidizer. Among the pre-cooler 18, the carbon monoxide selective oxidizer 19, and the post-cooler 20 for the carbon monoxide selective oxidizer, the first-stage carbon monoxide converter 15, the intermediate cooler 16 for the carbon monoxide converter, and the second stage The carbon monoxide converter 17 and the precooler 18 for the carbon monoxide selective oxidizer are applied.
[0060]
The carbon monoxide processing apparatus 2 according to the present embodiment includes a first-stage carbon monoxide converter 15, an intercooler 16 for a carbon monoxide converter, a second-stage carbon monoxide converter 17, and a front-end for a carbon monoxide selective oxidizer. The cooler 18 is integrally assembled as one block 32b, and the integrally assembled block 32b is covered with a heat insulating material 33 such as a divided ceramic. The symbol FG indicated by a broken line indicates the flow of the fuel reformed gas.
[0061]
As described above, in the present embodiment, the first-stage carbon monoxide converter 15, the intercooler 16 for the carbon monoxide converter, the second-stage carbon monoxide converter 17, the pre-cooler 18 for the carbon monoxide selective oxidizer Are integrated as one block body 32b, and the integrally assembled block body 32b is covered with the heat insulating material 33, so that the installation area of the carbon monoxide treatment apparatus 2 can be further reduced, and generation from each device is achieved. The heat release to the outside due to the exothermic reaction can be further reduced.
[0062]
FIG. 7 is a conceptual diagram showing a third embodiment of the carbon monoxide treatment device according to the present invention.
[0063]
The carbon monoxide processing apparatus 2 according to the present embodiment includes a first-stage carbon monoxide converter 15, an intercooler 16 for a carbon monoxide converter, a second-stage carbon monoxide converter 17, and a front-end for a carbon monoxide selective oxidizer. The present invention is applied to all devices including a pre-cooler 18, a carbon monoxide selective oxidizer 19, and a post-cooler 20 for a carbon monoxide selective oxidizer.
[0064]
The carbon monoxide processing apparatus 2 according to the present embodiment includes a first-stage carbon monoxide converter 15, an intercooler 16 for a carbon monoxide converter, a second-stage carbon monoxide converter 17, and a front-end for a carbon monoxide selective oxidizer. The pre-cooler 18, the carbon monoxide selective oxidizer 19, and the post-cooler 20 for the carbon monoxide selective oxidizer are integrally assembled as one block body 32c, and the integrated block body 32c is made of, for example, divided ceramics or the like. It is covered with a heat insulating material 33. The symbol FG indicated by a broken line indicates the flow of the fuel reformed gas.
[0065]
As described above, in the present embodiment, the first-stage carbon monoxide converter 15, the intercooler 16 for the carbon monoxide converter, the second-stage carbon monoxide converter 17, the pre-cooler 18 for the carbon monoxide selective oxidizer Since the carbon monoxide selective oxidizer 19 and the post-cooler for carbon monoxide selective oxidizer 20 are integrally assembled as one block body 32a, and the integrally assembled block body 32c is covered with the heat insulating material 33, The installation area of the carbon treatment device 2 can be further reduced, and heat radiation to the outside due to an exothermic reaction generated from each device can be further reduced.
[0066]
【The invention's effect】
As described above, the fuel cell power generation device according to the present invention includes a carbon monoxide treatment device including a first-stage carbon monoxide converter, an intercooler for a carbon monoxide converter, a second-stage carbon monoxide converter, A pre-cooler for carbon monoxide selective oxidizer, a carbon monoxide selective oxidizer, a post-cooler for carbon monoxide selective oxidizer, a first-stage carbon monoxide converter, a second-stage carbon monoxide converter, At least one or more metal monolith catalysts housed in each of the carbon monoxide selective oxidizers were configured as carriers having a honeycomb structure, and the cell density and the amount of catalyst carried on each carrier were varied. At the same time, it is possible to suppress a rapid rise in the reaction temperature by suppressing the reaction temperature with the fuel gas, and to secure a wider reaction area with the fuel reformed gas, thereby making it possible to reduce the catalyst volume.
[0067]
In addition, since each device is integrated and the integrated carbon monoxide treatment device is covered with a heat insulating material, the installation area can be further reduced, and the reaction of the catalyst of the carbon monoxide treatment device can be reduced. Since the accompanying heat radiation to the outside is further reduced, the power generation efficiency of the fuel cell can be increased, and the startup time can be shortened.
[Brief description of the drawings]
FIG. 1 is a schematic system diagram showing an embodiment of a fuel cell power generator according to the present invention.
FIG. 2 is a conceptual diagram showing that a metal monolith catalyst is housed in a container in the carbon monoxide treatment device of the fuel cell power generation device according to the present invention.
FIG. 3 is a conceptual diagram showing a first embodiment of a reactor included in the carbon monoxide treatment device of the fuel cell power generator according to the present invention.
FIG. 4 is a conceptual diagram showing a second embodiment of the reactor included in the carbon monoxide processing device of the fuel cell power generator according to the present invention.
FIG. 5 is a conceptual diagram showing a first embodiment of a carbon monoxide treatment device according to the present invention.
FIG. 6 is a conceptual diagram showing a second embodiment of a carbon monoxide treatment device according to the present invention.
FIG. 7 is a conceptual diagram showing a third embodiment of the carbon monoxide treatment device according to the present invention.
[Explanation of symbols]
1 Fuel reforming system
2 Carbon monoxide treatment system
3 Power generation system
4 desulfurizer
5 Preheater
6 Reformer
7 Steam generator
8 Air supply device
9 Startup fuel supply system
10 Burner for starting
11 Steam supply system
12 Reforming catalyst
13 Exhaust gas system
14 Water supply system
15 First stage carbon monoxide converter
16 Intercooler for carbon monoxide transformer
17 2nd stage carbon monoxide transformer
18 Precooler for carbon monoxide selective oxidizer
19 Carbon monoxide selective oxidizer
20 Post-cooler for carbon monoxide selective oxidizer
21 Air supply system
22 pump
23 Fuel cell body
24 Anode off-gas system
25 Main burner
26 Metal monolith catalyst
26a 1st metal monolith catalyst
26b Second metal monolith catalyst
27 Reactor fuselage
27a First reactor body
27b second reactor body
28 spatial domain
29 Fuel reformed gas inlet nozzle
30 Fuel reformed gas outlet nozzle
31a, 31b Space area
32a, 32b, 32c Block body
33 Insulation

Claims

A fuel reforming system for reforming a hydrocarbon-based raw fuel into a hydrogen-rich gas, a carbon monoxide converter and a monoxide for reducing the concentration of carbon monoxide contained in the fuel reformed gas from the fuel reforming system The electric power generated by the electrochemical reaction between the hydrogen in the fuel reformed gas discharged from the carbon monoxide treatment system and the oxygen in the air, and a carbon monoxide treatment system composed of a carbon selective oxidizer And a power generating system for taking out a fuel cell, wherein a metal honeycomb carrying a catalytically active component is disposed in at least one of the reactor body of the carbon monoxide converter and the carbon monoxide selective oxidizer. A fuel cell power generator, comprising a plurality of the above-mentioned structures connected to each other, and a space region provided between the metal honeycombs.

A fuel reforming system for reforming a hydrocarbon-based raw fuel into a hydrogen-rich gas, a carbon monoxide converter and a monoxide for reducing the concentration of carbon monoxide contained in the fuel reformed gas from the fuel reforming system The electric power generated by the electrochemical reaction between the hydrogen in the fuel reformed gas discharged from the carbon monoxide treatment system and the oxygen in the air, and a carbon monoxide treatment system composed of a carbon selective oxidizer And a power generation system for extracting the fuel gas, wherein the carbon monoxide treatment system comprises a first-stage carbon monoxide converter, a second-stage carbon monoxide converter, and a carbon monoxide selective oxidizer, Along with the arrangement in series along the flow of the, while having an intercooler for carbon monoxide converter between the first stage carbon monoxide converter and the second stage carbon monoxide converter, Between the inlet and outlet sides of the carbon monoxide selective oxidizer Fuel cell system according to claim 1, characterized in that a carbon monoxide selective oxidation dexterity precooler and carbon monoxide selective oxidation dexterity post-cooler, respectively.

At least one of the first-stage carbon monoxide converter, the second-stage carbon monoxide converter, and the carbon monoxide selective oxidizer has a catalytically active component in metal honeycombs having different cell densities. 3. The fuel cell power generator according to claim 2, wherein a plurality of supported metal monolith catalysts are accommodated.

At least one or more of the first-stage carbon monoxide converter, the second-stage carbon monoxide converter, and the carbon monoxide selective oxidizer have a plurality of metals having different amounts of catalytically active components loaded therein. 3. The fuel cell power generator according to claim 2, wherein a monolith catalyst is accommodated.

Among the first-stage carbon monoxide converter, the second-stage carbon monoxide converter, and the carbon monoxide selective oxidizer, at least one or more reactor bodies accommodate a plurality of metal monolith catalysts, 3. The fuel cell power generator according to claim 2, wherein a space region is formed between the plurality of metal monolith catalysts and on each of an inlet side and an outlet side thereof.

The carbon monoxide treatment system comprises a first-stage carbon monoxide converter, an intercooler for the carbon monoxide converter, and a second-stage carbon monoxide converter, which are integrally assembled as a single block, and which are integrally assembled. 3. The fuel cell power generator according to claim 2, wherein the fuel cell power generator is coated with a heat insulating material.

The intercooler for a carbon monoxide converter according to claim 6 cools the reformed gas at the outlet of the first-stage carbon monoxide converter and supplies it to the second-stage carbon monoxide converter, and secures steam for reforming. A fuel cell power generator, further heating water heated by a steam generator provided in the fuel reforming system.

The carbon monoxide treatment system comprises a first-stage carbon monoxide converter, an intercooler for a carbon monoxide converter, a second-stage carbon monoxide converter, and a pre-cooler for a carbon monoxide selective oxidizer in one block body. A fuel cell power generator characterized in that it is configured to be integrally assembled, and the integrally assembled block body is covered with a heat insulating material.

The pre-cooler for carbon monoxide selective oxidizer of claim 8 cools the reformed gas at the outlet of the second-stage carbon monoxide converter and supplies it to the carbon monoxide selective oxidizer, and secures the reforming steam. A fuel cell power generator, further heating the water heated by the steam generator and the intercooler for the carbon monoxide converter.

The carbon monoxide treatment system includes a first-stage carbon monoxide converter, an intercooler for a carbon monoxide converter, a second-stage carbon monoxide converter, a pre-cooler for a carbon monoxide selective oxidizer, and a carbon monoxide selector. A fuel cell power generator, wherein an oxidizer and a post-cooler for a carbon monoxide selective oxidizer are integrally assembled as one block body, and the integrally assembled block body is covered with a heat insulating material.

The carbon monoxide selective oxidizer post-cooler according to claim 10, wherein the reformed gas at the outlet of the carbon monoxide selective oxidizer is cooled and supplied to a fuel cell anode of a power generation system to secure fuel for reforming. A fuel cell power generation apparatus characterized in that water supplied to a reforming steam generator is preheated.