JP2004075435A

JP2004075435A - Fuel reforming device

Info

Publication number: JP2004075435A
Application number: JP2002236019A
Authority: JP
Inventors: Minoru Mizusawa; 水澤　実; Sakae Chijiiwa; 千々岩　榮; Masahito Tamura; 田村　雅人
Original assignee: IHI Corp
Current assignee: IHI Corp
Priority date: 2002-08-13
Filing date: 2002-08-13
Publication date: 2004-03-11

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reforming device in which a furnace tube is sufficiently heated to a red-heated state to sufficiently heat a reforming tube by radiant heat transfer, thereby, the heat transfer area of the reforming tube is decreased to make the reforming tube small-sized, the upper end of the reforming tube is not exposed to high temperature, a drift is prevented in a combustion gas flowing downward between the inner cylinder of a vacuum heat insulating vessel and the furnace tube, the heat amount inputted into each reforming tube is made uniform to thereby improve the performance of the reformer and miniaturize the reformer. <P>SOLUTION: The fuel reforming device houses the reforming tube 13 in the passage 12 between an inner cylinder 9a of the vacuum heat insulating vessel 9 and the furnace tube 11 disposed in the inner tube 9a. A space where the combustion gas 28 generated by a combustor 10 rises is formed between the furnace tube 11 and a guide cylinder 21 housed in the furnace tube 11, while a spiral plate 22 is disposed in the passage 12 to make the combustion gas 28 descending in the passage 12 intersect with the reforming tube 13. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、燃料改質装置に関するものである。
【０００２】
【従来の技術】
一般に、燃料電池は、水の電気分解とは逆に水素と酸素を結合させて、その時に発生する電気と熱を取り出すものであり、その発電効率の高さや環境への適合性から、家庭用燃料電池コージェネレーションシステムや燃料電池自動車としての開発が盛んに行われているが、そうした燃料電池の燃料となる水素は、ナフサ、灯油等の石油系燃料や都市ガス等を改質器で改質して製造される。
【０００３】
図３は改質器が設けられる設備の一例として、定置式の固体高分子型燃料電池（ＰＥＦＣ：Ｐｏｌｙｍｅｒ　Ｅｌｅｃｔｒｏｌｙｔｅ　Ｆｕｅｌ　Ｃｅｌｌ）の全体系統を表わすものであって、１は改質器、２は改質器１から排出される排ガスの熱により水を蒸発させて水蒸気を発生させる水蒸発器、３は前記排ガスの熱によりナフサ等の原燃料を気化させる原燃料気化器、４は改質器１へ供給する原料ガスの脱硫を行う脱硫器、５は改質器１で改質した改質ガスを冷却水で所要温度（およそ２００〜２５０℃前後）に温度降下させＣＯとＨ_２ＯをＣＯ_２とＨ_２に変換する低温シフトコンバータ、６は低温シフトコンバータ５を通過した改質ガスを冷却水で冷却し酸化反応によってＣＯを除去する選択酸化ＣＯ除去器、７は選択酸化ＣＯ除去器６を通過した改質ガスを加湿する加湿器、８はカソード８ａとアノード８ｂを有する固体高分子型燃料電池である。
【０００４】
図３に示される設備においては、水が水蒸発器２で水蒸気とされ、且つナフサ等の原燃料が原燃料気化器３で気化されて原料ガスとされ、前記水蒸気を混合した原料ガスが脱硫器４へ導かれ、該脱硫器４で脱硫された原料ガスが改質器１へ導かれ、該改質器１で改質された改質ガスが低温シフトコンバータ５と選択酸化ＣＯ除去器６と加湿器７とを介して固体高分子型燃料電池８のアノード８ｂへ導かれると共に、空気が加湿器７を介して固体高分子型燃料電池８のカソード８ａへ導かれ、発電が行われるようになっており、又、前記アノード８ｂから排出されるアノードオフガスは、改質器１における燃料ガスとして再利用される一方、前記カソード８ａから排出される水は、固体高分子型燃料電池８と選択酸化ＣＯ除去器６と低温シフトコンバータ５それぞれの冷却水、並びに原料ガスに混合される水蒸気の一部として用いられるようになっている。
【０００５】
従来、前記改質器１と、その関連機器としての水蒸発器２、原燃料気化器３、脱硫器４、低温シフトコンバータ５、及び選択酸化ＣＯ除去器６は、燃料改質装置として一つのユニットにまとめられており、斯かる燃料改質装置としては、例えば特願２００２−１４０１４９号明細書で開示したバーナ燃焼タイプの装置が提案されている。
【０００６】
而して、斯かる燃料改質装置は図４、図５に示され、図中、図３に示すものと同一の符号を付した部分は同一のものを表わしている。図４、図５に示す燃料改質装置では、改質器１とその関連機器（水蒸発器２、原燃料気化器３、脱硫器４、低温シフトコンバータ５、及び選択酸化ＣＯ除去器６）とからなるユニットに対し、内筒９ａと外筒９ｂとの間に真空の断熱層９ｃが形成される真空断熱容器９を被せて覆うことにより、燃料改質装置を構成するようにしている。
【０００７】
本図示例の場合、前記真空断熱容器９の内筒９ａ自体を改質器１の一部として利用するようにし、該内筒９ａの内部における中心部に、燃焼器１０から噴射される燃焼ガスが流通する炉筒１１を配置すると共に、該炉筒１１と前記内筒９ａとの間に燃焼ガスの流路１２を形成し、該流路１２内に、内部に改質触媒（図示せず）が装填され原料ガスを流通させてその改質を行うための複数（図５の例では六本）の改質管１３を並設し、改質器１を構成するようにしてある。なお、前記改質管１３は、内管１３ａと外管１３ｂとからなる二重管構造としてあり、原料ガスを内管１３ａと外管１３ｂとの間に形成される空間内を上昇させて前記燃焼ガスと熱交換させた後、その上端で折り返して内管１３ａ内の空間を下降させるようにしてある。
【０００８】
前記改質器１の炉筒１１は、ベースプレート１４から立設されたベース内筒１６の上端部に連結配置してあり、ベースプレート１４の外周端縁から立上がる長さの短いベース外筒１５の上端部に対し、前記真空断熱容器９の下端部を図示していないボルト・ナット等の締結手段により着脱自在となるよう気密に接続し、前記ベースプレート１４とベース内筒１６とベース外筒１５と真空断熱容器９の内筒９ａとで画成され且つ前記燃焼ガスの流路１２に連通する筒状の空間１７内に、前記改質器１の関連機器としての水蒸発器２、原燃料気化器３、脱硫器４、低温シフトコンバータ５、及び選択酸化ＣＯ除去器６を配設するようにしてある。
【０００９】
前記ベース内筒１６の内部には、前記燃焼器１０へ空気を供給するための空気流路１８を形成すると共に、その軸心部に、前記燃焼器１０へアノードオフガス等の燃料ガスを供給するための燃料ガス供給管１９を配設し、又、起動時には、燃焼用燃料供給管２０から前記燃焼器１０へ燃焼用燃料を供給するようにしてある。
【００１０】
図４の燃料改質装置においては、真空断熱容器９をユニットに被せるだけで断熱層９ｃの施工が行われるため、断熱層９ｃの施工の手間が大幅に軽減され、しかも、改質器１内の触媒交換や点検等のメンテナンスの際には、真空断熱容器９を開放するだけで済み、迅速に作業を行うことができる。
【００１１】
又、容器として内筒９ａと外筒９ｂとの間に真空の断熱層９ｃが形成される真空断熱容器９を採用しているため、断熱性能が極めて高くなり、断熱層９ｃの容積が低減され、装置を小型化することが可能となる一方、放散熱量が抑えられ、熱効率の向上にも役立つこととなる。
【００１２】
更に、真空断熱容器９の内筒９ａ内部を改質器１の燃焼ガスの流路１２としているため、装置全体の構造が単純となり、コストダウンにつながり、更に、前記改質器１を、燃焼器１０から噴射される燃焼ガスが流通する炉筒１１と、該炉筒１１と真空断熱容器９の内筒９ａとの間に形成される燃焼ガスの流路１２に並設され且つ内部に改質触媒が装填され原料ガスを流通させてその改質を行うための複数の改質管１３とから構成してあるため、改質管１３の多管化と燃焼器１０での高温燃焼による放射伝熱利用により改質器１の全長を短くすることが可能となり、これに伴って、水蒸発器２、原燃料気化器３、脱硫器４、低温シフトコンバータ５、選択酸化ＣＯ除去器６等の関連機器を改質器１の下側に配置でき、燃料改質装置の高さを低くすることができる。
【００１３】
なお、通常運転時には、改質器１には原燃料が供給され、燃料ガスを燃焼させた燃焼ガスは、改質器１と、水蒸発器２並びに原燃料気化器３において原燃料と熱交換し、およそ２００℃程度に温度が下がり、低温シフトコンバータ５や選択酸化ＣＯ除去器６における反応の温度レベルになるため、前記燃焼ガスの流路となる筒状の空間１７内に低温シフトコンバータ５や選択酸化ＣＯ除去器６等の反応器を剥き出しで配置しても不要な熱交換が起こる心配はない。
【００１４】
こうして、装置の小型化並びに熱効率向上を図ることができ、更に、断熱層９ｃの施工の手間を大幅に低減し得、メンテナンスも容易に行うことができる。
【００１５】
【発明が解決しようとする課題】
上述のように、図４、図５に示すバーナ燃焼式の燃焼改質装置は、種々の優れた利点を有する。しかし、燃焼ガスは断面積の大きな炉筒１１内を上昇しているため、炉筒１１を対流伝熱により十分赤熱させることができず、改質管１３へ効率良く放射伝熱を行うことができない。従って、改質管１３の表面積（伝熱面積）を大きくする必要があり、改質管１３を十分に小型化することができない。
【００１６】
又、燃焼ガスの温度は炉筒１１の上端に達するまでに十分下降していないため、炉筒１１上端で反転して真空断熱容器９の内筒９ａと炉筒１１との間の流路に導入される燃焼ガスの温度は高く、従って、内筒９ａと炉筒１１との間の流路に配設された改質管１３の上端側は高温に曝されるため、改質管の材料を耐熱合金としなければならず、価格が高価となる。
【００１７】
更に、真空断熱容器９の内筒９ａと炉筒１１との間の流路を下方へ流れる燃焼ガスは、改質管１３に沿って真下に流れるため伝熱効率が小さく、しかも偏流が生じるため、改質管１３毎の入熱量が不均等となり、改質器１の性能は低くしかも改質管１３を十分に小型化することが困難である。
【００１８】
本発明は、上述の実情に鑑み、炉筒内を流れる燃焼ガスによる対流伝熱が促進されるようにして炉筒の赤熱を十分に行い得るようにすると共に、改質管を放射伝熱により十分に加熱し得るようにし、以って、改質管の伝熱面積を小さくして改質管の更なる小型化を図り、又、改質管の上端が高温に曝されないようにして改質管として耐熱合金以外の材料を使用し得るようにし、更に真空断熱容器の内筒と炉筒との間の流路を下方へ流れる燃焼ガスに偏流が生じないようにすると共に、改質管毎の入熱量が均等となるようにして、改質器の性能向上及びより一層の小型化を可能とした燃焼改質装置を提供することを目的としてなしたものである。
【００１９】
【課題を解決するための手段】
請求項１の燃料改質装置は、容器の内筒内に配置した炉筒と前記内筒との間に形成された流路に改質管が収納され、且つ燃焼器で生成されて前記炉筒内を上昇した燃焼ガスが前記流路を下降して改質器内を流れる原料ガスを改質し得るようにした燃料改質装置であって、前記炉筒と炉筒内に収納された案内筒との間には、燃焼器で生成されて前記流路の上端側へ導入される燃焼ガスが上昇する隙間が形成されたものである。
【００２０】
請求項２の燃料改質装置は、容器の内筒内に配置した炉筒と前記内筒との間に形成された流路に改質管が収納され、且つ燃焼器で生成されて前記炉筒内を上昇した燃焼ガスが前記流路を下降して改質器内を流れる原料ガスを改質し得るようにした燃料改質装置であって、前記流路内には螺旋板を設けて前記炉筒上端で反転して前記流路を下降する燃焼ガスが前記改質管を横切るごとく流れるよう構成したものである。
【００２１】
請求項３の燃料改質装置は、容器の内筒内に配置した炉筒と前記内筒との間に形成された流路に改質管が収納され、且つ燃焼器で生成されて前記炉筒内を上昇した燃焼ガスが前記流路を下降して改質器内を流れる原料ガスを改質し得るようにした燃料改質装置であって、前記炉筒と炉筒内に収納された案内筒との間には、燃焼器で生成されて前記流路の上端側へ導入される燃焼ガスが上昇する隙間が形成され、前記流路内には螺旋板を設けて前記炉筒上端で反転して前記流路を下降する燃焼ガスが前記改質管を横切るごとく流れるよう構成したものである。
【００２２】
本発明においては、燃焼ガスは炉筒と炉筒内に収納された案内筒との間の隙間を通って上昇しつつ炉筒を対流伝熱により加熱させて赤熱させ、炉筒の上端で反転して内筒と炉筒とによる流路内に設けられた螺旋板に案内されつつ下降する。而して、改質管は炉筒の放射伝熱により加熱されると共に、螺旋板に案内されて改質管を横切るよう流れつつ下降する燃焼ガスによる対流伝熱により加熱される。
【００２３】
本発明の燃料改質装置によれば、燃焼ガスを、炉筒と案内筒との間の狭い隙間に上方へ向け且つ改質管を流れる原料ガスと並行流となるよう流して炉筒を赤熱させるようにしているため、炉筒から改質管へ効率良く放射伝熱を行うことができる。従って、改質管の表面積（伝熱面積）を削減することができ、改質管の小型化が可能となる。
【００２４】
又、改質管は高温に曝されることはないため、改質管の材料を一般のステンレスを使用することができ、コストを安価にすることができる。
【００２５】
更に真空断熱容器の内筒と炉筒との間の空間を下方へ流れる燃焼ガスは、螺旋板により案内されて全ての改質管を径方向へ横切るよう流れるため、燃焼ガスの流速は、螺旋板がなくて真下に流れる場合より速くなって約４倍の大きい伝熱効率を得ることができる。このため、対流伝熱が促進され、又、全ての改質管に対し均等なガス流量で伝熱される結果、改質管毎の入熱量が均等となって加熱むらがなくなり、改質器は高い改質性能を得ることができると共に改質管の小型化が可能となる。
【００２６】
【発明の実施の形態】
以下、本発明の実施の形態を図示例と共に説明する。
図１、図２は本発明を実施する形態の一例であって、図中、図４と同一の符号を付した部分は同一のものを表わしている。而して本図示例の燃焼改質装置の基本的な構成は図４に示す従来のものと略同様であるが、本図示例の特徴とするところは、図１に示すごとく、炉筒１１内を挿通して炉筒１１上端の上方まで延在する案内筒２１を炉筒１１に対し同心状に設けると共に、真空断熱容器９の内筒９ａと炉筒１１で形成される流路１２に改質管１３を包囲するよう螺旋板２２を設けた点にある。
【００２７】
案内筒２１は一般のステンレス製であり、内部は中空状でその下端は閉塞されている。又、案内筒２１の上端には炉筒１１よりも大径の案内板２３が取付けられており、炉筒１１と案内筒２１との間の隙間を上昇した燃焼ガスは、案内板２３により案内されて反転し、内筒９ａと炉筒１１との間の流路１２に導入されるようになっている。
【００２８】
図中、１５ａはベース外筒１５の側部に接続した排気口、２４は空気供給管、２５はアノードオフガスである燃料ガス、２６はナフサ等の燃焼用燃料、２７は空気、２８は燃焼ガス、２９は改質されつつある原料ガス、３０は排気であり、図示してないがナフサ等の原燃料は原燃料気化器３に導入されるようになっており、水は水蒸発器２に導入されるようになっており、改質ガスは選択酸化ＣＯ除去器６を経て図３に示す加湿器７から固体高分子型燃料電池８のアノード８ｂに導入されるようになっている。
【００２９】
次に、上記図示例の作動を図３をも参照しつつ説明する。
図３に示す固体高分子型燃料電池８で発電を行う場合には、原燃料を改質器１で改質する必要がある。このため、図１に示す燃料改質装置においては、水が水蒸発器２で水蒸気とされ、且つナフサ等の原燃料は原燃料気化器３で気化されて原料ガスとされ、前記水蒸気を混合した原料ガスは脱硫器４へ導かれ、該脱硫器４で脱硫された後、原料ガス２９は改質器１における改質管１３の外管１３ｂと内管１３ａとの間に導かれて上昇し、改質管１３の上端で反転して内管１３ａ内部を下降し、この上昇及び下降の間に以下で詳述するように、燃焼ガス２８により加熱されて改質される。
【００３０】
一方、燃料ガス２５及び燃焼用燃料２６並びに空気供給管２４から送給された空気は燃焼器１０で燃焼して高温（約１２００℃）の燃焼ガス２８が生成され、燃焼ガス２８は、炉筒１１と案内筒２１との間の狭い隙間を偏流することなく均一且つ高速で上昇する。上昇時の燃焼ガス２８の流れは、改質管１３を上昇若しくは下降する原料ガス２９に対して並行流となる。而して、燃焼ガス２８を炉筒１１と案内筒２１との間の狭い隙間に上方へ向け且つ改質管１３を流れる原料ガス２９と並行流となるよう流すと、燃焼ガス２８による対流伝熱が促進されて炉筒１１が赤熱され、炉筒１１の放射伝熱により改質管１３が加熱される。
【００３１】
炉筒１１と案内筒２１との間の狭い隙間を上端まで上昇した燃焼ガス２８は、案内板２３により反転させられて内筒９ａと炉筒１１との間の流路１２を螺旋板２２に沿って螺旋状に改質管１３を径方向へ横切るように流れつつ下降し、改質管１３を対流伝熱により加熱し、しかる後、水蒸発器２、脱硫器４、低温シフトコンバータ５、原燃料気化器３、選択酸化ＣＯ除去器６が収納されている筒状の空間１７を通ってベース外筒１５下端部に設けられている燃焼ガス排出口１５ａから排気３０として外部に排出される。
【００３２】
改質管１３内を上方及び下方に流れる原料ガス２９は、燃焼ガス２８により加熱された炉筒１１の放射伝熱により加熱されると共に、内筒９ａと炉筒１１との間の流路１２を螺旋板２２に沿って螺旋状に改質管１３を径方向へ横切るように流れつつ下降する燃焼ガス２８による対流伝熱により加熱され、改質される。
【００３３】
本図示例では、燃焼ガス２８を、炉筒１１と案内筒２１との間の狭い隙間に上方へ向け且つ改質管１３を流れる原料ガス２９と並行流となるよう流して炉筒１１を対流伝熱により赤熱させるようにしているため、炉筒１１から改質管１３へ効率良く放射伝熱を行うことができる。従って、改質管１３の表面積（伝熱面積）を削減することができ、図４に示す燃料改質装置よりも一層改質管１３の小型化が可能となる。
【００３４】
又、燃焼ガス２８は対流伝熱により炉筒１１を加熱し、炉筒１１は炉筒１１下端よりも下方の改質器１の入側付近の、低温で入熱量の大きな領域を放射伝熱により加熱しているため、炉筒１１と案内筒２１との間の隙間の上端部での燃焼ガス２８の温度は下降して燃焼器１０の燃焼温度（１２００℃）よりも低下し、且つ改質に十分な８００℃程度になる。従って、改質管１３に高価な耐熱合金を用いる必要がなく、一般のステンレス鋼を使用することができるため、燃料改質装置のコストダウンを図ることができる。
【００３５】
真空断熱容器９の内筒９ａと炉筒１１との間の流路１２を下方へ流れる燃焼ガス２８は、螺旋板２２により案内されて全ての改質管１３を径方向へ横切るよう流れるため、燃焼ガス２８の流速は、螺旋板２２がなくて真下に流れる場合より速くなって約４倍の大きい伝熱効率を得ることができる。このため、対流伝熱が促進され、又、全ての改質管１３に対し均等なガス流量で伝熱される結果、改質管１３毎の入熱量が均等となって加熱むらがなくなる。その結果、改質器１は高い改質性能を得ることができる。更に、改質管１３の伝熱効率が大きいため、この点からも改質管１３の小型化が可能となる。
【００３６】
改質器１で改質された改質ガスは低温シフトコンバータ５と選択酸化ＣＯ除去器６を経てベース外筒１５の下端部から燃料改質装置の外部に送給されて図３に示す加湿器７に導入され、加湿器７から固体高分子型燃料電池８のアノード８ｂへ導かれると共に、空気が加湿器７を介して固体高分子型燃料電池８のカソード８ａへ導かれ、発電が行われる。
【００３７】
なお、本発明の燃料改質装置においては、選択酸化ＣＯ除去器の代わりにいわゆるメタネーション反応を利用したメターネータを用いることもできること、その他、本発明の要旨を逸脱しない範囲内において種々変更を加え得ることは勿論である。
【００３８】
【発明の効果】
以上、説明したように本発明の請求項１〜３記載の燃料改質装置によれば、下記のごとき種々の優れた効果を奏し得る。
Ｉ）燃焼ガスを、炉筒と案内筒との間の狭い隙間に上方へ向け且つ改質管を流れる改質される原料ガスと並行流となるよう流して炉筒を赤熱させるようにしているため、炉筒から改質管へ効率良く放射伝熱を行うことができる。従って、改質管の表面積（伝熱面積）を削減することができ、図４の燃料改質装置よりも一層改質管の小型化が可能となる。
ＩＩ）改質管は高温に曝されることはないため、改質管の材料を一般のステンレスを使用することができ、コストを安価にすることができる。
ＩＩＩ）真空断熱容器の内筒と炉筒との間の流路を下方へ流れる燃焼ガスは、螺旋板により案内されて全ての改質管を径方向へ横切るよう流れるため、燃焼ガスの流速は、螺旋板がなくて真下に流れる場合より速くなって約４倍の大きい伝熱効率を得ることができる。このため、対流伝熱が促進され、又、全ての改質管に対し均等なガス流量で伝熱される結果、改質管毎の入熱量が均等となって加熱むらがなくなり、改質器は高い改質性能を得ることができると共に、更なる改質管の小型化が可能となる。
【図面の簡単な説明】
【図１】本発明の燃料改質装置の実施の形態の一例の縦断面図である。
【図２】図１のＩＩ−ＩＩ方向矢視図である。
【図３】改質器が設けられる設備の一例を表わす全体系統図である。
【図４】バーナ燃焼タイプの燃料改質装置の一例の縦断面図である。
【図５】図４のＶ−Ｖ方向矢視図である。
【符号の説明】
１　　改質器
９　　真空断熱容器（容器）
９ａ　　　　　　　　内筒
１０　　燃焼器
１１　　炉筒
１３　　改質管
２１　　案内筒
２２　　螺旋板
２８　　燃焼ガス
２９　　原料ガス[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel reformer.
[0002]
[Prior art]
In general, a fuel cell combines hydrogen and oxygen, as opposed to the electrolysis of water, to extract electricity and heat generated at that time. The development of fuel cell cogeneration systems and fuel cell vehicles is being actively pursued.Hydrogen, the fuel for such fuel cells, is reformed from petroleum fuels such as naphtha and kerosene and city gas using a reformer. Manufactured.
[0003]
FIG. 3 shows an entire system of a stationary polymer electrolyte fuel cell (PEFC) as an example of equipment provided with a reformer, where 1 is a reformer and 2 is a reformer. A water evaporator for evaporating water by the heat of the exhaust gas discharged from the reformer 1 to generate water vapor; 3, a raw fuel vaporizer for vaporizing a raw fuel such as naphtha by the heat of the exhaust gas; A desulfurizer 5 for desulfurizing the raw material gas supplied to the reformer 1, and the reformed gas reformed in the reformer 1 is cooled to a required temperature (about 200 to 250 ° C.) with cooling water to reduce CO and H ₂ O to CO. ₂ is a low-temperature shift converter for converting into H ₂ , 6 is a selective oxidized CO remover that cools the reformed gas passing through the low-temperature shift converter 5 with cooling water and removes CO by an oxidation reaction, and 7 is a selective oxidized CO remover. A humidifier for humidifying the reformed gas passing through 6, and 8 is a polymer electrolyte fuel cell having a cathode 8a and an anode 8b.
[0004]
In the equipment shown in FIG. 3, water is converted into steam in a water evaporator 2, and raw fuel such as naphtha is vaporized in a raw fuel vaporizer 3 to form a raw material gas. The raw material gas desulfurized by the desulfurizer 4 is guided to the reformer 1, and the reformed gas reformed by the reformer 1 is converted into a low-temperature shift converter 5 and a selective oxidized CO remover 6. The air is guided to the anode 8b of the polymer electrolyte fuel cell 8 through the humidifier 7 and the humidifier 7, and the air is guided to the cathode 8a of the polymer electrolyte fuel cell 8 through the humidifier 7 to generate power. The anode off-gas discharged from the anode 8b is reused as fuel gas in the reformer 1, while the water discharged from the cathode 8a is supplied to the polymer electrolyte fuel cell 8 Selective CO remover 6 and low temperature shift Converter 5 is adapted to be used as part of the steam to be mixed to the respective cooling water, and the raw material gas.
[0005]
Conventionally, the reformer 1 and its related equipment, a water evaporator 2, a raw fuel vaporizer 3, a desulfurizer 4, a low-temperature shift converter 5, and a selective oxidized CO remover 6, are one fuel reformer. As a fuel reforming apparatus, for example, a burner combustion type apparatus disclosed in Japanese Patent Application No. 2002-140149 has been proposed.
[0006]
Thus, such a fuel reforming apparatus is shown in FIGS. 4 and 5, in which parts denoted by the same reference numerals as those shown in FIG. 3 represent the same parts. 4 and 5, the reformer 1 and its related equipment (water evaporator 2, raw fuel vaporizer 3, desulfurizer 4, low-temperature shift converter 5, and selective oxidation CO remover 6) The fuel reforming apparatus is configured by covering a unit consisting of: a vacuum heat insulating container 9 in which a vacuum heat insulating layer 9c is formed between the inner cylinder 9a and the outer cylinder 9b.
[0007]
In the case of the illustrated example, the inner cylinder 9a of the vacuum insulated container 9 itself is used as a part of the reformer 1, and the combustion gas injected from the combustor 10 is provided at a central portion inside the inner cylinder 9a. Is arranged, and a flow path 12 of the combustion gas is formed between the furnace cylinder 11 and the inner cylinder 9a. A reforming catalyst (not shown) is formed inside the flow path 12 inside. ), A plurality (six in the example of FIG. 5) of reforming tubes 13 for circulating the raw material gas and reforming the raw material gas are arranged in parallel to constitute the reformer 1. The reforming pipe 13 has a double pipe structure including an inner pipe 13a and an outer pipe 13b, and raises a raw material gas in a space formed between the inner pipe 13a and the outer pipe 13b to increase the After exchanging heat with the combustion gas, it is turned back at the upper end to lower the space in the inner tube 13a.
[0008]
The furnace tube 11 of the reformer 1 is connected to the upper end of a base inner tube 16 erected from the base plate 14, and has a short base outer tube 15 rising from the outer peripheral edge of the base plate 14. The lower end of the vacuum insulated container 9 is air-tightly connected to the upper end so as to be detachable by fastening means such as bolts and nuts (not shown), and the base plate 14, the base inner cylinder 16, and the base outer cylinder 15 are connected to each other. In a cylindrical space 17 defined by the inner cylinder 9a of the vacuum insulated container 9 and communicating with the combustion gas flow path 12, a water evaporator 2 as a related device of the reformer 1 and a raw fuel vaporizer are provided. A device 3, a desulfurizer 4, a low-temperature shift converter 5, and a selective oxidation CO remover 6 are provided.
[0009]
An air flow path 18 for supplying air to the combustor 10 is formed inside the base inner cylinder 16, and a fuel gas such as an anode off-gas is supplied to the combustor 10 at an axial portion thereof. And a fuel gas supply pipe 19 for supplying fuel to the combustor 10 from the combustion fuel supply pipe 20 at the time of startup.
[0010]
In the fuel reformer of FIG. 4, since the construction of the heat insulating layer 9 c is performed only by covering the unit with the vacuum heat insulating container 9, the time and labor required for the construction of the heat insulating layer 9 c are greatly reduced. For maintenance such as catalyst replacement and inspection, it is only necessary to open the vacuum insulated container 9 and work can be performed quickly.
[0011]
Further, since the vacuum heat insulating container 9 in which the vacuum heat insulating layer 9c is formed between the inner cylinder 9a and the outer cylinder 9b is adopted as the container, the heat insulating performance becomes extremely high, and the volume of the heat insulating layer 9c is reduced. This makes it possible to reduce the size of the device, while suppressing the amount of heat dissipated, which also contributes to improving the thermal efficiency.
[0012]
Further, since the inside of the inner cylinder 9a of the vacuum insulated container 9 is used as the combustion gas flow path 12 of the reformer 1, the structure of the entire apparatus is simplified, which leads to cost reduction. A furnace tube 11 through which the combustion gas injected from the heater 10 flows, and a combustion gas flow path 12 formed between the furnace tube 11 and the inner cylinder 9a of the vacuum heat insulating container 9 are arranged side by side and internally remodeled. And a plurality of reforming tubes 13 for carrying the reforming of the raw material gas through which the reforming catalyst 13 is loaded. The use of heat transfer makes it possible to shorten the overall length of the reformer 1, and accordingly, the water evaporator 2, the raw fuel vaporizer 3, the desulfurizer 4, the low-temperature shift converter 5, the selective oxidation CO remover 6, etc. Related equipment can be arranged under the reformer 1, and the height of the fuel reformer can be reduced. Rukoto can.
[0013]
During normal operation, raw fuel is supplied to the reformer 1, and the combustion gas obtained by burning the fuel gas exchanges heat with the raw fuel in the reformer 1, the water evaporator 2, and the raw fuel vaporizer 3. Then, the temperature drops to about 200 ° C., and the temperature of the reaction in the low-temperature shift converter 5 and the selective oxidized CO remover 6 becomes equal to the low-temperature shift converter 5. Even if the reactor such as the selective oxidation CO remover 6 or the like is exposed, there is no fear that unnecessary heat exchange occurs.
[0014]
Thus, the size of the apparatus can be reduced and the thermal efficiency can be improved. Further, the labor for installing the heat insulating layer 9c can be greatly reduced, and the maintenance can be easily performed.
[0015]
[Problems to be solved by the invention]
As described above, the burner combustion type combustion reformer shown in FIGS. 4 and 5 has various excellent advantages. However, since the combustion gas is rising inside the furnace tube 11 having a large cross-sectional area, the furnace tube 11 cannot be sufficiently glowed by convective heat transfer, and radiant heat transfer to the reforming tube 13 can be efficiently performed. Can not. Therefore, it is necessary to increase the surface area (heat transfer area) of the reforming tube 13, and it is not possible to sufficiently reduce the size of the reforming tube 13.
[0016]
In addition, since the temperature of the combustion gas has not sufficiently decreased before reaching the upper end of the furnace tube 11, the temperature of the combustion gas is reversed at the upper end of the furnace tube 11 so that the temperature of the combustion gas flows into the flow path between the inner tube 9a of the vacuum insulated container 9 and the furnace tube 11. The temperature of the introduced combustion gas is high, and therefore, the upper end side of the reforming tube 13 disposed in the flow path between the inner tube 9a and the furnace tube 11 is exposed to a high temperature. Must be a heat-resistant alloy, and the price is high.
[0017]
Further, the combustion gas flowing downward in the flow path between the inner cylinder 9a of the vacuum heat insulating container 9 and the furnace cylinder 11 flows directly below the reforming pipe 13 and thus has a low heat transfer efficiency, and a drift occurs. The amount of heat input to each reforming tube 13 becomes uneven, so that the performance of the reformer 1 is low, and it is difficult to sufficiently reduce the size of the reforming tube 13.
[0018]
The present invention has been made in view of the above-described circumstances, and enables convective heat transfer by combustion gas flowing in a furnace tube to be promoted so that red heat of the furnace tube can be sufficiently performed. The reforming tube is sufficiently heated so that the heat transfer area of the reforming tube is reduced to further reduce the size of the reforming tube, and the upper end of the reforming tube is not exposed to high temperatures. The material other than the heat-resistant alloy can be used as the quality pipe, and further, the combustion gas flowing downward through the flow path between the inner cylinder and the furnace cylinder of the vacuum insulated container is prevented from being deflected, and the reforming pipe is formed. It is an object of the present invention to provide a combustion reformer in which the amount of heat input is made uniform so that the performance of the reformer can be improved and the size of the reformer can be further reduced.
[0019]
[Means for Solving the Problems]
2. The fuel reforming apparatus according to claim 1, wherein a reforming tube is housed in a flow passage formed between the furnace tube disposed in the inner tube of the container and the inner tube, and the reformer tube is generated by a combustor, and is provided in the furnace. A fuel reformer in which a combustion gas that has risen in a cylinder is capable of reforming a raw material gas flowing in a reformer by descending the flow path, and is contained in the furnace cylinder and the furnace cylinder. A gap is formed between the guide cylinder and the space where the combustion gas generated in the combustor and introduced into the upper end of the flow passage rises.
[0020]
3. The fuel reforming apparatus according to claim 2, wherein the reforming tube is housed in a flow passage formed between the furnace tube disposed in the inner tube of the container and the inner tube, and the reformer tube is generated by a combustor and is provided in the furnace. A fuel reforming apparatus in which the combustion gas that has risen in the cylinder is capable of reforming the raw material gas flowing in the reformer by descending the flow path, wherein a spiral plate is provided in the flow path. The combustion gas which is inverted at the upper end of the furnace cylinder and descends in the flow path flows so as to cross the reforming pipe.
[0021]
4. The fuel reformer according to claim 3, wherein a reforming tube is housed in a flow passage formed between the furnace tube disposed in the inner tube of the container and the inner tube, and the reformer tube is generated by a combustor and is formed in the furnace. A fuel reformer in which a combustion gas that has risen in a cylinder is capable of reforming a raw material gas flowing in a reformer by descending the flow path, and is contained in the furnace cylinder and the furnace cylinder. A gap is formed between the guide tube and the combustion gas generated in the combustor and introduced into the upper end of the flow passage. The gap is formed in the flow passage. The combustion gas that reverses and descends in the flow path flows so as to cross the reforming pipe.
[0022]
In the present invention, the combustion gas rises through a gap between the furnace tube and the guide tube housed in the furnace tube, and heats the furnace tube by convective heat transfer to cause it to glow red, and is inverted at the upper end of the furnace tube. Then, it descends while being guided by a spiral plate provided in a flow path formed by the inner cylinder and the furnace cylinder. Thus, the reforming tube is heated by the radiant heat transfer of the furnace tube, and is also heated by the convective heat transfer of the combustion gas that is guided by the spiral plate and flows across the reforming tube and descends.
[0023]
According to the fuel reformer of the present invention, the combustion gas flows upward in the narrow gap between the furnace tube and the guide tube so as to be in parallel with the raw material gas flowing through the reforming tube, thereby causing the furnace tube to heat up. Therefore, radiant heat transfer can be efficiently performed from the furnace tube to the reforming tube. Therefore, the surface area (heat transfer area) of the reforming tube can be reduced, and the size of the reforming tube can be reduced.
[0024]
Further, since the reforming tube is not exposed to a high temperature, ordinary stainless steel can be used as the material of the reforming tube, and the cost can be reduced.
[0025]
Further, the combustion gas flowing downward in the space between the inner cylinder and the furnace cylinder of the vacuum insulated container flows through all the reforming tubes in the radial direction by being guided by the spiral plate. It is faster than the case of flowing directly below without a plate, and it is possible to obtain a heat transfer efficiency about four times as large. As a result, convection heat transfer is promoted, and heat is transferred to all reforming tubes at an equal gas flow rate, resulting in uniform heat input to each reforming tube, thereby eliminating uneven heating. It is possible to obtain high reforming performance and to downsize the reforming tube.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 and FIG. 2 show an example of an embodiment of the present invention. In the figure, portions denoted by the same reference numerals as those in FIG. 4 represent the same components. The basic structure of the combustion reforming apparatus of this embodiment is substantially the same as that of the conventional combustion reformer shown in FIG. 4, but the feature of this embodiment is, as shown in FIG. A guide tube 21 that extends through the inside of the furnace tube 11 and extends above the upper end of the furnace tube 11 is provided concentrically with respect to the furnace tube 11, and is provided in the inner tube 9 a of the vacuum heat insulating container 9 and the flow path 12 formed by the furnace tube 11. The point is that a spiral plate 22 is provided so as to surround the reforming tube 13.
[0027]
The guide cylinder 21 is made of general stainless steel, has a hollow interior and a lower end closed. A guide plate 23 having a larger diameter than the furnace tube 11 is attached to the upper end of the guide tube 21, and the combustion gas that has risen in the gap between the furnace tube 11 and the guide tube 21 is guided by the guide plate 23. Then, it is inverted and introduced into the flow path 12 between the inner cylinder 9a and the furnace cylinder 11.
[0028]
In the drawing, 15a is an exhaust port connected to the side of the base outer cylinder 15, 24 is an air supply pipe, 25 is a fuel gas as an anode off gas, 26 is a fuel for combustion such as naphtha, 27 is air, and 28 is a combustion gas. , 29 is a raw material gas being reformed, and 30 is an exhaust gas. Although not shown, raw fuel such as naphtha is introduced into the raw fuel vaporizer 3, and water is supplied to the water evaporator 2. The reformed gas is introduced from the humidifier 7 shown in FIG. 3 to the anode 8 b of the polymer electrolyte fuel cell 8 via the selective oxidation CO remover 6.
[0029]
Next, the operation of the illustrated example will be described with reference to FIG.
When power is generated by the polymer electrolyte fuel cell 8 shown in FIG. 3, the raw fuel needs to be reformed by the reformer 1. For this reason, in the fuel reforming apparatus shown in FIG. 1, water is converted into steam in a water evaporator 2, and raw fuel such as naphtha is vaporized in a raw fuel vaporizer 3 to form a raw material gas. The raw material gas is guided to the desulfurizer 4 and is desulfurized by the desulfurizer 4. After that, the raw material gas 29 is guided between the outer tube 13b and the inner tube 13a of the reforming tube 13 in the reformer 1 and rises. Then, it is inverted at the upper end of the reforming tube 13 and descends inside the inner tube 13a, and is heated and reformed by the combustion gas 28 during the ascending and descending as described in detail below.
[0030]
On the other hand, the fuel gas 25, the combustion fuel 26, and the air supplied from the air supply pipe 24 are burned in the combustor 10 to generate a high-temperature (about 1200 ° C.) combustion gas 28. It rises uniformly and at high speed without drifting in a narrow gap between 11 and the guide cylinder 21. The flow of the combustion gas 28 at the time of ascending becomes parallel to the raw material gas 29 which ascends or descends the reforming pipe 13. When the combustion gas 28 flows upward into the narrow gap between the furnace tube 11 and the guide tube 21 and flows in parallel with the raw material gas 29 flowing through the reforming tube 13, convection transmission by the combustion gas 28 occurs. The heat is promoted and the furnace tube 11 is red-heated, and the reforming tube 13 is heated by the radiant heat transfer of the furnace tube 11.
[0031]
The combustion gas 28 that has risen to the upper end through the narrow gap between the furnace tube 11 and the guide tube 21 is reversed by the guide plate 23 and the flow path 12 between the inner tube 9a and the furnace tube 11 is formed on the spiral plate 22. Descends while flowing spirally across the reforming tube 13 in the radial direction, and heats the reforming tube 13 by convective heat transfer, after which the water evaporator 2, desulfurizer 4, low-temperature shift converter 5, The raw fuel vaporizer 3 and the selective oxidizing CO remover 6 are exhausted to the outside as exhaust gas 30 through a cylindrical space 17 in which a combustion gas outlet 15a provided at the lower end of the base outer cylinder 15 passes. .
[0032]
The raw material gas 29 flowing upward and downward in the reforming pipe 13 is heated by radiant heat transfer of the furnace tube 11 heated by the combustion gas 28, and the flow path 12 between the inner tube 9 a and the furnace tube 11 is heated. Is heated by convective heat transfer by the combustion gas 28 descending while flowing spirally along the spiral plate 22 in the radial direction of the reforming tube 13 and reforming.
[0033]
In the illustrated example, the combustion gas 28 flows upward into the narrow gap between the furnace tube 11 and the guide tube 21 and flows in parallel with the raw material gas 29 flowing through the reforming tube 13 to convect the furnace tube 11. Since red heat is generated by heat transfer, radiant heat transfer from the furnace tube 11 to the reforming tube 13 can be efficiently performed. Accordingly, the surface area (heat transfer area) of the reforming tube 13 can be reduced, and the size of the reforming tube 13 can be further reduced as compared with the fuel reformer shown in FIG.
[0034]
Further, the combustion gas 28 heats the furnace tube 11 by convective heat transfer, and the furnace tube 11 radiates heat through a region at a low temperature and a large amount of heat input near the inlet side of the reformer 1 below the lower end of the furnace tube 11. , The temperature of the combustion gas 28 at the upper end of the gap between the furnace tube 11 and the guide tube 21 falls and falls below the combustion temperature of the combustor 10 (1200 ° C.). It is about 800 ° C, which is sufficient for quality. Therefore, it is not necessary to use an expensive heat-resistant alloy for the reforming tube 13 and general stainless steel can be used, so that the cost of the fuel reforming apparatus can be reduced.
[0035]
Since the combustion gas 28 flowing downward in the flow path 12 between the inner cylinder 9a of the vacuum heat insulating container 9 and the furnace cylinder 11 is guided by the spiral plate 22 and flows across all the reforming tubes 13 in the radial direction, The flow velocity of the combustion gas 28 is higher than when flowing immediately below without the spiral plate 22, and it is possible to obtain about four times greater heat transfer efficiency. For this reason, convective heat transfer is promoted, and heat is transferred to all the reforming tubes 13 at a uniform gas flow rate. As a result, the amount of heat input to each reforming tube 13 becomes uniform, and uneven heating is eliminated. As a result, the reformer 1 can obtain high reforming performance. Further, since the heat transfer efficiency of the reforming tube 13 is large, the size of the reforming tube 13 can be reduced from this point as well.
[0036]
The reformed gas reformed in the reformer 1 is sent from the lower end of the base outer cylinder 15 to the outside of the fuel reformer through the low-temperature shift converter 5 and the selective oxidation CO remover 6, and is humidified as shown in FIG. Is introduced into the humidifier 7 and is guided from the humidifier 7 to the anode 8b of the polymer electrolyte fuel cell 8 and air is guided through the humidifier 7 to the cathode 8a of the polymer electrolyte fuel cell 8 and power is generated. Is
[0037]
In the fuel reformer of the present invention, a methanator utilizing a so-called methanation reaction may be used instead of the selective oxidation CO remover, and other various changes may be made without departing from the gist of the present invention. Obviously you can get it.
[0038]
【The invention's effect】
As described above, according to the fuel reformer according to claims 1 to 3 of the present invention, various excellent effects as described below can be obtained.
I) The combustion gas is caused to flow red in the narrow gap between the furnace tube and the guide tube so as to flow in parallel with the raw material gas to be reformed flowing through the reforming tube, thereby causing the furnace tube to glow red. Therefore, radiant heat transfer can be efficiently performed from the furnace tube to the reforming tube. Accordingly, the surface area (heat transfer area) of the reforming tube can be reduced, and the size of the reforming tube can be further reduced as compared with the fuel reformer shown in FIG.
II) Since the reforming tube is not exposed to a high temperature, general stainless steel can be used as the material of the reforming tube, and the cost can be reduced.
III) Since the combustion gas flowing downward in the flow path between the inner cylinder and the furnace cylinder of the vacuum insulated vessel flows through all the reforming tubes in the radial direction guided by the spiral plate, the flow rate of the combustion gas is Therefore, the heat transfer efficiency can be increased by about four times, as compared with the case where there is no spiral plate and the air flows directly below. As a result, convection heat transfer is promoted, and heat is transferred to all reforming tubes at an equal gas flow rate. High reforming performance can be obtained, and the size of the reforming tube can be further reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an example of an embodiment of a fuel reformer of the present invention.
FIG. 2 is a view in the direction of arrows II-II in FIG.
FIG. 3 is an overall system diagram illustrating an example of equipment provided with a reformer.
FIG. 4 is a longitudinal sectional view of an example of a burner combustion type fuel reformer.
FIG. 5 is a view in the direction of arrows VV in FIG. 4;
[Explanation of symbols]
1 Reformer 9 Vacuum insulated container (container)
9a Inner tube 10 Combustor 11 Furnace tube 13 Reforming tube 21 Guide tube 22 Spiral plate 28 Combustion gas 29 Source gas

Claims

A reforming tube is housed in a flow path formed between the furnace tube disposed in the inner tube of the vessel and the inner tube, and the combustion gas generated in the combustor and ascending in the furnace tube flows into the flow tube. A fuel reforming apparatus which is capable of reforming a raw material gas flowing down a path and flowing through a reformer, wherein a combustor is provided between the furnace tube and a guide tube housed in the furnace tube. A fuel reformer, characterized in that a gap is formed in which the combustion gas generated in step (1) and introduced into the upper end of the flow passage rises.

A reforming tube is housed in a flow path formed between the furnace tube disposed in the inner tube of the vessel and the inner tube, and the combustion gas generated in the combustor and ascending in the furnace tube flows into the flow tube. A fuel reforming apparatus which is capable of reforming a raw material gas flowing down a reformer by descending a passage, wherein a spiral plate is provided in the flow passage, and the flow is inverted at an upper end of the furnace tube. A fuel reformer characterized in that a combustion gas descending on a path flows so as to cross the reformer pipe.

A reforming tube is housed in a flow path formed between the furnace tube disposed in the inner tube of the vessel and the inner tube, and the combustion gas generated in the combustor and ascending in the furnace tube flows into the flow tube. A fuel reforming apparatus which is capable of reforming a raw material gas flowing down a path and flowing through a reformer, wherein a combustor is provided between the furnace tube and a guide tube housed in the furnace tube. A gap is formed in which the combustion gas generated in and introduced into the upper end side of the flow path rises, and a spiral plate is provided in the flow path, and the combustion is reversed at the upper end of the furnace tube and descends the flow path. A fuel reformer characterized in that the gas flows so as to cross the reformer tube.