JPH07187603A - Heat transmitting method in reformer - Google Patents
Heat transmitting method in reformerInfo
- Publication number
- JPH07187603A JPH07187603A JP5334674A JP33467493A JPH07187603A JP H07187603 A JPH07187603 A JP H07187603A JP 5334674 A JP5334674 A JP 5334674A JP 33467493 A JP33467493 A JP 33467493A JP H07187603 A JPH07187603 A JP H07187603A
- Authority
- JP
- Japan
- Prior art keywords
- reformer
- tube
- gas
- inner tube
- solid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
- H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
- H01M8/0612—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants from carbon-containing material
- H01M8/0625—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants from carbon-containing material in a modular combined reactor/fuel cell structure
- H01M8/0631—Reactor construction specially adapted for combination reactor/fuel cell
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、燃料電池用改質ガスを
製造するための改質器における伝熱の促進に関する。よ
り詳しくは、本発明は、バヨネット型二重管式触媒管を
有する改質器における熱の利用効率を高める方法、並び
にそのような方法に用いられる当該改質器に関する。FIELD OF THE INVENTION The present invention relates to promoting heat transfer in a reformer for producing a reformed gas for a fuel cell. More specifically, the present invention relates to a method for improving heat utilization efficiency in a reformer having a bayonet type double-tube catalyst tube, and the reformer used in such a method.
【０００２】[0002]
【従来の技術】燃料電池発電は、発電効率が高く環境に
対する影響が少ない発電方式として注目されている。燃
料電池は、原理的には、水素と酸素とをそれぞれ燃料極
（水素極）および空気極（酸素極）に連続的に供給し、
両極間に電解質を配置することによって、両極に接続し
た外部回路に直流の電流を取り出すものである。2. Description of the Related Art Fuel cell power generation has been attracting attention as a power generation method that has high power generation efficiency and little influence on the environment. In principle, a fuel cell continuously supplies hydrogen and oxygen to a fuel electrode (hydrogen electrode) and an air electrode (oxygen electrode),
By arranging an electrolyte between both electrodes, a direct current is taken out to an external circuit connected to both electrodes.
【０００３】燃料電池には、電解質として何を用いるか
によって、アルカリ型（ＡＦＣ）、リン酸型（ＰＡＦ
Ｃ）、溶融炭酸塩型（ＭＣＦＣ）などの方式がある。こ
れらはいずれも燃料極に水素（純水素又は粗製水素）を
供給する点では同じであるが、当該水素に二酸化炭素あ
るいは一酸化炭素の混入が許されるかどうかという点に
おいて相違する。すなわち、アルカリ型の場合には、二
酸化炭素は電解質である水酸化カリウムの機能を低下さ
せ、一酸化炭素は触媒として用いられている白金を被毒
させることから、いずれも燃料電池の性能を劣化させる
ことになり、混入は許されない。このため、この型では
実質的に純水素を燃料ガスとして用いなくてはならない
という難点がある。一方、リン酸型の場合には、一酸化
炭素はやはり触媒として用いられている白金を被毒させ
るので混入が許されないが、二酸化炭素の混入は問題な
いため、一酸化炭素を一酸化炭素変成器でスチームと反
応させて二酸化炭素及び水素に変えることにより、粗製
水素が使用可能である。さらに、溶融炭酸塩型の場合に
は、白金触媒を用いないためいずれの混入も全く問題な
いばかりか、一酸化炭素は燃料極で生成される水分と上
記一酸化炭素変成反応により水素を発生するので燃料と
しても有効に利用される。溶融炭酸塩型にはこのほかに
も経済的に多くのメリットがあるため、中小規模の火力
発電の代替用として有望視されている。なお燃料電池と
しては、上記以外にも固体電解質型（ＳＯＦＣ）や高分
子型（ＰＦＣ）などが知られており、それぞれ特徴を持
っているが、いずれも燃料極に水素を供給する点では同
じである。In the fuel cell, alkaline type (AFC) and phosphoric acid type (PAF) are used depending on what is used as the electrolyte.
C), molten carbonate type (MCFC) and the like. These are the same in that hydrogen (pure hydrogen or crude hydrogen) is supplied to the fuel electrode, but differ in whether or not carbon dioxide or carbon monoxide can be mixed in the hydrogen. That is, in the case of the alkaline type, carbon dioxide deteriorates the function of potassium hydroxide as an electrolyte, and carbon monoxide poisons platinum used as a catalyst, so that the performance of the fuel cell deteriorates. It will be allowed and mixing is not allowed. For this reason, this type has a drawback that substantially pure hydrogen must be used as the fuel gas. On the other hand, in the case of the phosphoric acid type, carbon monoxide poisons platinum, which is also used as a catalyst, so mixing is not allowed, but mixing of carbon dioxide is not a problem, so carbon monoxide is converted to carbon monoxide. Crude hydrogen can be used by reacting it with steam in a vessel to convert it to carbon dioxide and hydrogen. Further, in the case of the molten carbonate type, since no platinum catalyst is used, any mixing is not a problem at all, and carbon monoxide generates hydrogen by the water produced at the fuel electrode and the carbon monoxide shift reaction. Therefore, it can be effectively used as fuel. Since the molten carbonate type has many other economical advantages, it is regarded as a promising alternative to small- and medium-sized thermal power generation. Other than the above, solid electrolyte type (SOFC) and polymer type (PFC) are known as fuel cells, and each has its own characteristics, but both are the same in that hydrogen is supplied to the fuel electrode. Is.
【０００４】リン酸型や溶融炭酸塩型燃料電池の燃料極
に供給される粗製水素は、一般に天然ガス（主成分はメ
タン）を原料としてこれにスチームを反応させて作る。
このときの反応はたとえば次式（１）または（２）に従
うと考えられる。 ＣＨ4 ＋ Ｈ2Ｏ → ＣＯ ＋ ３Ｈ2 （１） ＣＨ4 ＋ ２Ｈ2Ｏ → ＣＯ2 ＋ ４Ｈ2 （２） これらの反応は吸熱反応であり、通常は触媒の存在下に
６００℃〜１０００℃で行われる。上記反応を行わせる
装置が改質器であり、一般に触媒を充填した反応管に原
料ガス（天然ガスとスチーム）を流通させ、バーナーま
たは触媒燃焼による高温流体で外部から加熱する構造に
なっている。Crude hydrogen supplied to the fuel electrode of a phosphoric acid type or molten carbonate type fuel cell is generally produced by reacting steam with natural gas (main component is methane) as a raw material.
The reaction at this time is considered to follow, for example, the following formula (1) or (2). CH 4 + H 2 O → CO + 3H 2 (1) CH 4 + 2H 2 O → CO 2 + 4H 2 (2) These reactions are endothermic reactions and are usually 600 ° C to 1000 ° C in the presence of a catalyst. Done in. The apparatus for performing the above reaction is a reformer, and generally has a structure in which a raw material gas (natural gas and steam) is circulated in a reaction tube filled with a catalyst and is heated from outside by a burner or a high temperature fluid by catalytic combustion. .
【０００５】改質器としては、従来からバヨネット型二
重管式触媒管を有するものがよく用いられている。その
代表的な構造の概略を図１に示す。図１において、原料
となる天然ガスとスチームは缶体１の一端（図では頂
部）の原料ガス入口２から缶体内部に導入され、バヨネ
ット型二重管式触媒管を構成する内管３と外管４の間隙
を通過して流れる。当該間隙には改質触媒５が充填され
ており、この間に天然ガスとスチームが反応して水素を
含む改質ガスとなる。次いで、生成した改質ガスは内管
３内を通過し、マニホールド６から改質ガス出口７を経
て燃料電池（図示せず）に供給される。缶体１の他端
（図では底部）には燃焼ガス供給部分が設けられ、これ
は例えば図１に示されるように燃焼室８、燃焼装置９、
燃焼ガス分散板１０等からなる。燃焼ガスは外管４の外
側（シェル側）を流れ、該触媒５を外側から加熱した
後、燃焼排ガス出口１１より排出される。内管３はマニ
ホールド６によって支持され、外管４は管板１２によっ
て支持されており、両管相互の位置関係は固定されてい
ないため、外管と内管との熱膨張の程度の違い（一般に
外管の方が高温になる）による応力を逃がすことがで
き、これが頻繁な起動停止や負荷変化を要求される燃料
電池用改質器においてバヨネット型触媒管を採用する１
つのメリットとなっている。なお燃焼装置で燃焼させる
ガスとしては、通常、燃料電池の燃料極側からの排ガス
（電池反応では供給されたすべての水素を利用できるわ
けではないので未利用の水素が残っている）を利用する
が、水素含有量が少なく発熱量が低い場合には自燃させ
ることが困難なので通常のバーナー燃焼でなく触媒燃焼
が用いられる。As the reformer, one having a bayonet type double tube type catalyst tube has been often used conventionally. The outline of the typical structure is shown in FIG. In FIG. 1, raw material natural gas and steam are introduced into the inside of a can body from a source gas inlet 2 at one end (top in the figure) of the can body 1 and an inner pipe 3 which constitutes a bayonet type double-tube catalyst pipe. It flows through the gap of the outer tube 4. The reforming catalyst 5 is filled in the gap, and the natural gas and steam react with each other during this period to form a reformed gas containing hydrogen. Next, the generated reformed gas passes through the inner pipe 3 and is supplied from the manifold 6 to the fuel cell (not shown) through the reformed gas outlet 7. The other end (bottom part in the figure) of the can body 1 is provided with a combustion gas supply part, which includes, for example, a combustion chamber 8, a combustion device 9, as shown in FIG.
Combustion gas dispersion plate 10 and the like. The combustion gas flows outside (shell side) of the outer pipe 4, heats the catalyst 5 from the outside, and is then discharged from the combustion exhaust gas outlet 11. Since the inner tube 3 is supported by the manifold 6 and the outer tube 4 is supported by the tube plate 12, the positional relationship between the two tubes is not fixed, and therefore the difference in the degree of thermal expansion between the outer tube and the inner tube ( Generally, the stress due to the outer tube becomes hotter) can be released, and the bayonet type catalyst tube is adopted in the reformer for fuel cells, which requires frequent start / stop and load changes.
It has one advantage. As the gas to be burned in the combustion device, exhaust gas from the fuel electrode side of the fuel cell is usually used (unused hydrogen remains because not all hydrogen supplied can be used in the cell reaction). However, when the hydrogen content is low and the calorific value is low, it is difficult to cause self-combustion, so catalytic combustion is used instead of normal burner combustion.
【０００６】[0006]
【発明が解決しようとする課題】上述のように、バヨネ
ット型二重管式触媒管内の原料ガスおよび改質ガスの流
れは、原料ガスが外管と内管の間隙を流れ、改質ガスが
内管内を原料ガスとは逆方向に流れるようになってい
る。このときのガスの温度は、該間隙の入口（触媒管の
基部）附近では比較的低温（６００℃程度以下）であ
り、間隙を通過するに従って上昇して該間隙の出口（触
媒管先端部）附近では、通常、９００℃にも達する。内
管内に充填物や構造物がない場合には、この高温ガス
（改質ガス）が内管内を通過する際における内管壁ある
いは該間隙領域との間の伝熱係数が小さいので効率のよ
い熱交換が行われず、この高温ガスは大して冷却されず
に改質ガス出口から排出される。したがって熱の有効利
用が図れず、また特にリン酸型のような低温型燃料電池
に利用する場合には、当該燃料電池発電システムにおけ
る冷却負荷を増大させることにもなる。As described above, the flow of the raw material gas and the reforming gas in the bayonet type double-tube catalyst tube is such that the raw material gas flows through the gap between the outer tube and the inner tube, and the reforming gas is It flows in the inner tube in the direction opposite to the source gas. The temperature of the gas at this time is a relatively low temperature (about 600 ° C. or less) near the inlet of the gap (the base of the catalyst tube), and rises as it passes through the gap to the outlet of the gap (the tip of the catalyst pipe). In the vicinity, it usually reaches 900 ° C. When there is no filling or structure in the inner pipe, the heat transfer coefficient between the high temperature gas (reformed gas) and the inner pipe wall or the gap region is small when passing through the inner pipe, which is efficient. No heat exchange takes place and this hot gas is not cooled much and is discharged from the reformed gas outlet. Therefore, effective use of heat cannot be achieved, and particularly when it is used for a low temperature type fuel cell such as a phosphoric acid type, it also increases the cooling load in the fuel cell power generation system.
【０００７】従来より、内管内を流れる改質ガスと間隙
内を流れる原料ガスもしくは間隙中の触媒層との間の伝
熱を促進するために、内管内にデミスターネットを充填
したりスリーブを設けたりすることが提案されている
（特開平４−３００６４２号公報参照）。しかしなが
ら、デミスターネットやスリーブはニッケルやクロムを
含む金属製であることから、その触媒作用により次式に
示すようなブドアール反応に従って炭素が析出しやす
く、これを防止するためにメタンを主成分とする天然ガ
ス原料の場合においてもスチームとカーボンのモル比
（Ｓ／Ｃ比）を３．０以下には下げられないという問題
がある。 ２ＣＯ → Ｃ ＋ ＣＯ2 Conventionally, in order to promote heat transfer between the reformed gas flowing in the inner pipe and the raw material gas flowing in the gap or the catalyst layer in the gap, the inner pipe is filled with a demister net or a sleeve is provided. It has been proposed (see Japanese Patent Laid-Open No. 4-300642). However, since the demister net and the sleeve are made of a metal containing nickel and chromium, the catalytic action of the demister net easily causes carbon to precipitate according to the Boudartreal reaction as shown in the following equation. To prevent this, methane is the main component. Even in the case of a natural gas raw material, there is a problem that the molar ratio of steam and carbon (S / C ratio) cannot be lowered to 3.0 or less. 2CO → C + CO 2
【０００８】改質反応が前記式（１）および（２）に従
うとした場合、理論上必要とされるＳ／Ｃ比はそれぞれ
１および２であるから、これが３．０以上であるという
ことはかなり過剰のスチームを添加していることを意味
し、改質器における熱負荷の増大およびスチーム消費の
増大という点で、改質ガスの製造コストの上昇につなが
っている。また、過剰のスチームの添加は改質ガス中の
水素および一酸化炭素の分圧の低下につながり、その結
果として発電効率が低下することにもなる。たとえば改
質器全圧が３．４３ｋｇ／ｃｍ2 でＳ／Ｃ比が３．０の
場合には、改質ガス中の水素および一酸化炭素の分圧は
２．２４ｋｇ／ｃｍ2 であり、これが溶融炭酸塩型燃料
電池の燃料極に供給されると発電効率（理論値）は４
１．５％となる。もし、Ｓ／Ｃ比を２．５に下げること
ができれば、上記分圧は２．４１ｋｇ／ｃｍ2 、発電効
率は４２．５％に上昇する。このため、改質器における
Ｓ／Ｃ比を理論比である２にできるだけ近づけることは
燃料電池の実用化にとって重要な課題である。Given that the reforming reaction complies with the above equations (1) and (2), the theoretically required S / C ratios are 1 and 2, respectively, so that it is 3.0 or more. This means that a considerable excess of steam is added, which leads to an increase in the reformed gas production cost in terms of an increase in heat load and an increase in steam consumption in the reformer. Moreover, the addition of excess steam leads to a decrease in the partial pressure of hydrogen and carbon monoxide in the reformed gas, resulting in a decrease in power generation efficiency. For example, when the reformer total pressure is 3.43 kg / cm 2 and the S / C ratio is 3.0, the partial pressure of hydrogen and carbon monoxide in the reformed gas is 2.24 kg / cm 2 . When this is supplied to the fuel electrode of the molten carbonate fuel cell, the power generation efficiency (theoretical value) is 4
It becomes 1.5%. If the S / C ratio can be reduced to 2.5, the partial pressure will be 2.41 kg / cm 2 and the power generation efficiency will be 42.5%. Therefore, making the S / C ratio in the reformer as close as possible to the theoretical ratio of 2 is an important issue for practical application of the fuel cell.
【０００９】[0009]
【課題を解決するための手段】本発明は、バヨネット型
二重管式触媒管を有する改質器において、該触媒管の内
管内にセラミック製の通気性固体を配置することによ
り、内管内を流れる高温の改質ガスと間隙内を流れる低
温の原料ガスとの間の伝熱を促進し、かつブドアール反
応を抑制してＳ／Ｃ比の低い条件下での改質器の運転を
可能とするものであり、かくして上記課題を解決するも
のである。According to the present invention, in a reformer having a bayonet type double tube type catalyst tube, a ceramic breathable solid is placed in the inner tube of the catalyst tube so that The heat transfer between the flowing high temperature reformed gas and the low temperature raw material gas flowing in the gap is promoted, and the Boudard reaction is suppressed to enable the operation of the reformer under the condition of low S / C ratio. Therefore, the above problems are solved.
【００１０】[0010]
【作用】バヨネット型触媒管の内管内に配置する通気性
固体は、内管内を流れる高温の改質ガスと接触して加熱
され、高温の改質ガスが有する熱エネルギーを内管内に
蓄積する役割と、かくして蓄積された熱エネルギーを放
射する役割を演ずる。一般にガス体の熱放射率は固体の
熱放射率に較べて極めて小さいため、ガス体からの放射
伝熱は上記改質ガスの温度および内管の容積程度ではほ
とんど問題にならない。したがって、改質ガスからの伝
熱は対流伝熱が主体となる。通気性固体は大きな伝熱面
積（接触面積）を提供し、改質ガスが有する熱エネルギ
ーを速やかに蓄積する。加熱された通気性固体は蓄積さ
れた熱エネルギーを内管壁に向けて放射し、内管壁を加
熱することになる。すなわち、内管内に通気性固体がな
い状態では、改質ガスから内管壁への伝熱は実質的に対
流伝熱のみによって行われ、しかもその伝熱面積はほぼ
内管壁の面積に等しいからあまり大きくはない。これに
対して、内管内に通気性固体を配置した状態では、改質
ガスから内管壁への伝熱は上記直接の対流伝熱と前記し
た通気性固体から内管壁への放射伝熱の組合せによる伝
熱によって行われることになり、伝熱効率が著しく向上
するのである。[Function] The air-permeable solid placed in the inner tube of the bayonet type catalyst tube is heated by contacting with the high temperature reformed gas flowing in the inner tube to accumulate the thermal energy of the high temperature reformed gas in the inner tube. It thus plays the role of radiating the thermal energy thus stored. Generally, the thermal emissivity of a gas body is extremely smaller than that of a solid body, so that the radiative heat transfer from the gas body causes almost no problem at the temperature of the reformed gas and the volume of the inner tube. Therefore, heat transfer from the reformed gas is mainly convective heat transfer. The breathable solid provides a large heat transfer area (contact area) and quickly accumulates the thermal energy of the reformed gas. The heated breathable solid will radiate the accumulated thermal energy towards the inner tube wall, heating the inner tube wall. That is, in the state where there is no breathable solid in the inner pipe, the heat transfer from the reformed gas to the inner pipe wall is substantially performed only by convection heat transfer, and the heat transfer area is almost equal to the area of the inner pipe wall. So not so big. On the other hand, when the permeable solid is placed inside the inner pipe, the heat transfer from the reformed gas to the inner pipe wall is the direct convection heat transfer described above and the radiative heat transfer from the permeable solid to the inner pipe wall described above. The heat transfer efficiency is remarkably improved because the heat transfer is performed by the combination of.
【００１１】一方、改質ガスにはメタンとスチームの反
応生成物として水素のみならず一酸化炭素も含まれ、特
にＳ／Ｃ比が低い条件では一酸化炭素の生成量が大き
い。この一酸化炭素は前記ブドアール反応（一酸化炭素
不均化反応）に従って炭素を析出する性質を有し、これ
は微粉となって改質ガスとともに流出すると下流の燃料
電池の電極板等を損傷するとともに、内管内の伝熱効率
を低下させたり或いは内管自体をを閉塞するおそれがあ
るため避ける必要がある。本発明では、通気性固体とし
てセラミック製のものを用いることにより、従来の金属
製の充填物もしくは構造物と較べてブドアール反応に対
する触媒作用を著しく低下させている。セラミックが金
属に較べてブドアール反応に対する触媒作用を示しにく
いということは本発明に至る過程で発明者が経験的に見
出したことであるが、その理由としては、一般に鉄、ニ
ッケル、クロムなどの遷移金属は一酸化炭素との親和性
が大きいため一酸化炭素を表面に吸着しやすいことによ
るものと考えられる。したがって、セラミックとしては
アルミナ、シリカなど典型元素の酸化物を主体とするも
のが好ましい。On the other hand, the reformed gas contains not only hydrogen but also carbon monoxide as a reaction product of methane and steam, and the amount of carbon monoxide produced is large especially under conditions where the S / C ratio is low. This carbon monoxide has a property of precipitating carbon according to the Budhard reaction (carbon monoxide disproportionation reaction), and if it becomes fine powder and flows out together with the reformed gas, it damages the electrode plate of the downstream fuel cell and the like. At the same time, the heat transfer efficiency in the inner pipe may be reduced, or the inner pipe itself may be blocked, so it is necessary to avoid it. In the present invention, by using a ceramic material as the breathable solid, the catalytic action for the Boudard reaction is remarkably reduced as compared with the conventional metallic filler or structure. The fact that ceramics are less likely to exhibit a catalytic action for the Bouddard reaction than metals is empirically found by the inventor in the process leading to the present invention. The reason is that in general, transitions of iron, nickel, chromium, etc. It is considered that the metal has a high affinity for carbon monoxide and thus is likely to adsorb carbon monoxide on the surface. Therefore, it is preferable that the ceramic mainly contains oxides of typical elements such as alumina and silica.
【００１２】上記のように、通気性固体は改質ガスから
の対流伝熱に関して大きな伝熱面積を提供するものであ
るため、その比表面積は大きいことが好ましいが、改質
ガスの流れに対してあまり大きな抵抗を示すことは好ま
しくない。そのような条件を満たす通気性固体として
は、セル数４〜４０個／２５ｍｍ程度、好ましくは６〜
１３個／２５ｍｍ程度の連続気孔を有するセラミックフ
ォームがある。このようなセラミックフォームには溶融
金属の濾過用として用いられるムライト、アルミナ、コ
ージライト、ジルコニア、炭化珪素などからなるものが
知られており、これは各種形状に成形することができ
る。したがって内管の断面形状にあわせて円柱状に成形
したものを用いれば、内管内への不均一充填や壁効果に
よる偏流を防止することができ、また充填作業の効率も
向上する。As mentioned above, since the breathable solid provides a large heat transfer area for convective heat transfer from the reformed gas, it is preferable that its specific surface area is large, but it is preferable for the reformed gas flow. It is not preferable to show too much resistance. As a breathable solid that satisfies such conditions, the number of cells is about 4 to 40 cells / about 25 mm, preferably 6 to
There is a ceramic foam having continuous pores of about 13/25 mm. As such a ceramic foam, those made of mullite, alumina, cordierite, zirconia, silicon carbide, etc., which are used for filtering molten metal, are known and can be molded into various shapes. Therefore, if a cylindrically shaped product is used according to the cross-sectional shape of the inner pipe, uneven filling into the inner pipe and uneven flow due to the wall effect can be prevented, and the filling work efficiency is also improved.
【００１３】通気性固体としては、触媒管の底部では改
質ガスの温度は９００℃程度に達するため、ある程度の
耐熱性が必要であるが、一般にセラミックは金属に較べ
て耐熱性が大きく、９００℃程度の耐熱性というのは上
記に挙げたようなセラミックであればほとんど問題のな
いレベルである。ムライト系、アルミナ系あるいは炭化
珪素系のものは特に耐熱性が大きい。As a breathable solid, since the temperature of the reformed gas reaches about 900 ° C. at the bottom of the catalyst tube, some heat resistance is required, but in general, ceramic has higher heat resistance than metal, and 900 The heat resistance of about 0 ° C. is a level at which there is almost no problem with the above-mentioned ceramics. Mullite-based, alumina-based, or silicon carbide-based materials have particularly high heat resistance.
【００１４】通気性固体は、上記したように、蓄熱媒体
としての性格をも有するものであるため、触媒管内の改
質反応の温度条件を安定に維持できるという効果を有す
る。すなわち、改質触媒が充填された内管と外管との間
隙においては、上部から底部に向かって一定の温度勾配
が形成され定常的に維持されることが、改質反応を安定
に行い一定の組成の改質ガスを燃料電池に供給するうえ
で重要であるが、内管内に熱容量の大きい充填物がある
とその蓄熱（緩衝）効果により上記温度勾配を安定に維
持するのに有効である。なお、通気性固体は必ずしも内
管内全域にわたって充填する必要はなく、内管内の略中
央域に充填することがしばしば好ましい場合がある。As described above, the breathable solid has a property as a heat storage medium, and therefore has an effect that the temperature condition of the reforming reaction in the catalyst tube can be stably maintained. That is, in the gap between the inner tube and the outer tube filled with the reforming catalyst, a constant temperature gradient is formed from the upper part to the bottom part and is constantly maintained, so that the reforming reaction is stably performed and constant. It is important to supply the reformed gas having the composition of 1 to the fuel cell, but if there is a filler with a large heat capacity in the inner tube, it is effective to maintain the above temperature gradient stably due to its heat storage (buffering) effect. . The breathable solid does not necessarily have to fill the entire area of the inner pipe, and it is often preferable to fill the substantially central region of the inner pipe.
【００１５】[0015]
【実施例】図２は本発明の好適な実施例を示す。この例
では図１に示す装置において、図２に示すように内管３
内部のほぼ全域にわたって、連続気泡を有するセラミッ
クフォームからなる通気性固体１３が配置されている。
このセラミックフォームからなる通気性固体は内管の内
径にあわせて円柱形に成形されている。また内管の入口
（図では下端）附近には通気性固体を支持するストッパ
ー１４が設けられている。該通気性固体を内管の出口側
（図では上方）から挿入し、内管内のほぼ全域が該通気
性固体で充填されるまで積み重ねていけば、簡単に装填
することができる。FIG. 2 shows a preferred embodiment of the present invention. In this example, in the device shown in FIG. 1, as shown in FIG.
A breathable solid 13 composed of a ceramic foam having open cells is arranged almost all over the inside.
The air-permeable solid made of this ceramic foam is formed into a cylindrical shape according to the inner diameter of the inner tube. Further, a stopper 14 for supporting the breathable solid is provided near the inlet (lower end in the figure) of the inner pipe. The breathable solid can be easily loaded by inserting it from the outlet side (upper side in the figure) of the inner pipe and stacking it until almost the entire area of the inner pipe is filled with the breathable solid.
【００１６】図２のバヨネット型触媒管５本を有する図
１に示すような装置を用いて天然ガスの改質を行った。
バヨネット型触媒管は、内管の外径が１６５．２ｍｍ、
外管の外径は２１６．３ｍｍである。改質触媒としては
東洋ＣＣＩ社製ＦＣＲ−４を２７００ｍｍの層高に充填
した。通気性固体としては公称＃０６（４〜９セル／２
５ミリ）のムライト系セラミックフォームを用い、内管
内に２７００ｍｍの層高で装填した。原料天然ガスの組
成は、 ＣＨ4 ８９．６％ Ｃ2Ｈ6 ５．２％ Ｃ3Ｈ8 ３．４％ Ｃ4Ｈ10 １．８％ であり、これを１７０Ｎｍ3 ／Ｈで流し、同時にスチー
ムを４０１ｋｇ／Ｈで流した（Ｓ／Ｃ＝２．５）。改質
器入口温度は４３４℃、触媒管先端部温度は８２０℃、
触媒管先端部圧力は１２．４ｋｇ／ｃｍ2Ｇ 、改質器出
口温度は６００℃であった。改質ガスの組成は、 Ｈ2 ５８．７％ ＣＯ １１．５％ ＣＯ2 ６．７％ ＣＨ4 ０．７％ Ｈ2Ｏ ２２．４％ であった。連続して８０００時間運転した後、通気性固
体を観察したところ、カーボンの析出はほとんど見られ
なかった。Natural gas was reformed using an apparatus as shown in FIG. 1 having five bayonet type catalyst tubes shown in FIG.
The bayonet type catalyst tube has an inner diameter of 165.2 mm,
The outer diameter of the outer tube is 216.3 mm. As a reforming catalyst, FCR-4 manufactured by Toyo CCI Co., Ltd. was filled in a layer height of 2700 mm. Nominal # 06 as breathable solid (4-9 cells / 2
(5 mm) mullite-based ceramic foam was used and loaded into the inner tube at a bed height of 2700 mm. The composition of the raw material natural gas is CH 4 89.6% C 2 H 6 5.2% C 3 H 8 3.4% C 4 H 10 1.8%, which is flowed at 170 Nm 3 / H at the same time. Steam was flushed at 401 kg / H (S / C = 2.5). The reformer inlet temperature is 434 ° C, the catalyst tube tip temperature is 820 ° C,
The pressure at the tip of the catalyst tube was 12.4 kg / cm 2 G, and the reformer outlet temperature was 600 ° C. The composition of the reformed gas was H 2 58.7% CO 11.5% CO 2 6.7% CH 4 0.7% H 2 O 22.4%. After continuously operating for 8000 hours, when the breathable solid was observed, almost no carbon deposition was observed.
【００１７】[0017]
【発明の効果】本発明によれば、通気性固体が高温の改
質ガスの熱を蓄積して内管壁に放射するため、改質ガス
から原料ガスへの伝熱が促進される。したがって、改質
ガスの熱エネルギーを改質反応に有効に利用することが
でき、また燃料電池システムにおける冷却負荷を低減す
ることができる。その際、ブドアール反応による通気性
固体上への炭素の析出がほとんどないため、Ｓ／Ｃ比を
２．５程度まで下げることが可能であり、燃料電池の発
電効率を上げることができる。According to the present invention, the permeable solid accumulates the heat of the high-temperature reformed gas and radiates it to the inner pipe wall, so that the heat transfer from the reformed gas to the raw material gas is promoted. Therefore, the thermal energy of the reformed gas can be effectively used for the reforming reaction, and the cooling load in the fuel cell system can be reduced. At that time, since there is almost no carbon deposition on the breathable solid due to the Boudart reaction, the S / C ratio can be lowered to about 2.5, and the power generation efficiency of the fuel cell can be increased.
【図１】 従来の改質器の例を示す。FIG. 1 shows an example of a conventional reformer.
【図２】 本発明の改質器の触媒管の例を示す。FIG. 2 shows an example of a catalyst tube of the reformer of the present invention.
１ 缶体 ２ 原料ガス入口 ３ 内管 ４ 外管 ５ 改質触媒 ６ マニホールド ７ 改質ガス出口 ８ 燃焼室 ９ 燃焼装置 １０ 燃焼ガス分散板 １１ 燃焼排ガス出口 １２ 管板 １３ 通気性固体 １４ ストッパー 1 can body 2 raw material gas inlet 3 inner pipe 4 outer pipe 5 reforming catalyst 6 manifold 7 reformed gas outlet 8 combustion chamber 9 combustion device 10 combustion gas dispersion plate 11 combustion exhaust gas outlet 12 tube plate 13 breathable solid 14 stopper
───────────────────────────────────────────────────── フロントページの続き (72)発明者 八木 宏 神奈川県横浜市鶴見区鶴見中央二丁目12番 １号 千代田化工建設株式会社内 (72)発明者 清水 良亮 神奈川県横浜市鶴見区鶴見中央二丁目12番 １号 千代田化工建設株式会社内 (72)発明者 森田 泰正 神奈川県横浜市鶴見区鶴見中央二丁目12番 １号 千代田化工建設株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroshi Yagi Inventor Hiroshi Yagi 12-12-1, Tsurumi Chuo, Tsurumi-ku, Yokohama-shi, Kanagawa Chiyoda Kako Construction Co., Ltd. (72) Ryosuke Shimizu Chuo, Tsurumi-ku, Tsurumi-ku, Yokohama, Kanagawa Chome 12-1 Chiyoda Kakoh Construction Co., Ltd. (72) Inventor Yasumasa Morita 2-12-1 Tsurumi Chuo, Tsurumi-ku, Yokohama-shi, Kanagawa Chiyoda Kakoh Construction Co., Ltd.
Claims (12)
質器を用い、天然ガスとスチームとを該改質器に供給し
て水素および一酸化炭素を主成分とする燃料電池用改質
ガスを得る方法において、該触媒管の内管内にセラミッ
ク製の通気性固体を配置することを特徴とする方法。1. A reformer for a fuel cell, which uses a reformer having a bayonet-type double-tube catalyst tube and supplies natural gas and steam to the reformer to contain hydrogen and carbon monoxide as main components. A method for obtaining a gas, characterized in that a breathable solid made of ceramic is arranged in an inner tube of the catalyst tube.
って配置される請求項１記載の方法。2. The method of claim 1, wherein the breathable solid is disposed substantially throughout the inner tube.
置される請求項１記載の方法。3. The method of claim 1, wherein the breathable solid is located in a generally central region within the inner tube.
ック多孔体である請求項１記載の方法。4. The method according to claim 1, wherein the breathable solid is a ceramic porous body having continuous pores.
成形されたものである請求項４記載の方法。5. The method according to claim 4, wherein the breathable solid is shaped to match the shape of the inner tube.
ージライト、ジルコニアまたは炭化珪素からなる請求項
４記載の方法。6. The method of claim 4, wherein the breathable solid comprises mullite, alumina, cordierite, zirconia or silicon carbide.
有する熱交換器型改質器において、該触媒管の内管内に
セラミック製の通気性固体を配置したことを特徴とする
改質器。7. A heat exchanger type reformer having a bayonet type double-tube catalyst tube in a can, wherein a ceramic permeable solid is arranged in the inner tube of the catalyst tube. vessel.
って配置された請求項７記載の改質器。8. The reformer according to claim 7, wherein the air-permeable solid is arranged over substantially the entire area of the inner pipe.
置された請求項７記載の改質器。9. The reformer according to claim 7, wherein the air-permeable solid is arranged in a substantially central region in the inner pipe.
ミック多孔体である請求項７記載の改質器。10. The reformer according to claim 7, wherein the breathable solid is a ceramic porous body having continuous pores.
て成形されたものである請求項１０記載の改質器。11. The reformer according to claim 10, wherein the breathable solid is formed in conformity with the shape of the inner tube.
コージライト、ジルコニアまたは炭化珪素からなる請求
項１０記載の改質器。12. The breathable solid is mullite, alumina,
The reformer according to claim 10, which is made of cordierite, zirconia, or silicon carbide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33467493A JP3499273B2 (en) | 1993-12-28 | 1993-12-28 | Heat transfer method in reformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33467493A JP3499273B2 (en) | 1993-12-28 | 1993-12-28 | Heat transfer method in reformer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07187603A true JPH07187603A (en) | 1995-07-25 |
| JP3499273B2 JP3499273B2 (en) | 2004-02-23 |
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ID=18279983
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33467493A Expired - Fee Related JP3499273B2 (en) | 1993-12-28 | 1993-12-28 | Heat transfer method in reformer |
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| Country | Link |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999054667A1 (en) * | 1998-04-21 | 1999-10-28 | Gastec N.V. | Method for treating a moist gas stream |
| JP2006027949A (en) * | 2004-07-15 | 2006-02-02 | Electric Power Dev Co Ltd | Method of using carbon oxide-containing gas |
| WO2007108543A1 (en) * | 2006-03-23 | 2007-09-27 | Ngk Insulators, Ltd. | Process for producing hydrogen using permselective membrane reactor and permselective membrane reactor |
| US11891302B2 (en) | 2020-03-17 | 2024-02-06 | Bayotech, Inc. | Hydrogen generation systems |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR102007767B1 (en) * | 2017-04-06 | 2019-08-07 | 주식회사 푸른기술에너지 | Reformer for fuel cell |
-
1993
- 1993-12-28 JP JP33467493A patent/JP3499273B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999054667A1 (en) * | 1998-04-21 | 1999-10-28 | Gastec N.V. | Method for treating a moist gas stream |
| JP2006027949A (en) * | 2004-07-15 | 2006-02-02 | Electric Power Dev Co Ltd | Method of using carbon oxide-containing gas |
| WO2007108543A1 (en) * | 2006-03-23 | 2007-09-27 | Ngk Insulators, Ltd. | Process for producing hydrogen using permselective membrane reactor and permselective membrane reactor |
| US7560090B2 (en) | 2006-03-23 | 2009-07-14 | Ngk Insulators, Ltd. | Process for producing hydrogen with permselective membrane reactor and permselective membrane reactor |
| JP5139971B2 (en) * | 2006-03-23 | 2013-02-06 | 日本碍子株式会社 | Hydrogen production method using selectively permeable membrane reactor |
| US11891302B2 (en) | 2020-03-17 | 2024-02-06 | Bayotech, Inc. | Hydrogen generation systems |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3499273B2 (en) | 2004-02-23 |
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