JP5237870B2 - High purity hydrogen production method - Google Patents

High purity hydrogen production method Download PDF

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JP5237870B2
JP5237870B2 JP2009094915A JP2009094915A JP5237870B2 JP 5237870 B2 JP5237870 B2 JP 5237870B2 JP 2009094915 A JP2009094915 A JP 2009094915A JP 2009094915 A JP2009094915 A JP 2009094915A JP 5237870 B2 JP5237870 B2 JP 5237870B2
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JP2010241657A (en
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昇 中尾
彰利 藤澤
真一 三浦
岳史 山下
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Kobe Steel Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Description

本発明は、燃料電池用の高純度水素の製造方法に関し、より詳細には、燃料電池設備を稼働するためのエネルギー源となる水素から、燃料電池の被毒成分であるＣＯガス成分を効率的に除去し、高純度水素を精製する方法に関わる。   The present invention relates to a method for producing high-purity hydrogen for a fuel cell, and more specifically, efficiently converts a CO gas component, which is a poisonous component of a fuel cell, from hydrogen serving as an energy source for operating a fuel cell facility. It is related to the method of purifying high purity hydrogen.

近年、地球環境の改善につながる燃料電池用の燃料として、水素への期待が高まっている。水素は、天然ガス、ナフサ、灯油、メタノールなどの炭化水素含有燃料と水蒸気を金属触媒の存在下で改質・変成した後、精製して得るのが一般的である。変成後のガス（変成ガス）には、水素以外に一酸化炭素（ＣＯ）、二酸化炭素（ＣＯ２）、メタン（ＣＨ４）、水（Ｈ２Ｏ）などが含まれており、とくに固体高分子型燃料電池などの低温形燃料電池の場合、燃料としての水素にＣＯが含まれると、燃料電池の電極用触媒(Ｐｔ)にＣＯが吸着して触媒が劣化し、出力が低下する。上記の改質・変成後のガス中に残留するＣＯは０．５〜１．０容量％程度であるが、上記電極用触媒の被毒劣化防止の観点からＣＯを１０ｐｐｍ以下とする必要がある。 In recent years, there is an increasing expectation for hydrogen as a fuel for fuel cells that leads to improvement of the global environment. In general, hydrogen is obtained by reforming and reforming a hydrocarbon-containing fuel such as natural gas, naphtha, kerosene, or methanol and steam in the presence of a metal catalyst. The metamorphic gas (metamorphic gas) contains carbon monoxide (CO), carbon dioxide (CO 2 ), methane (CH 4 ), water (H 2 O), etc. in addition to hydrogen. In the case of a low temperature fuel cell such as a molecular fuel cell, when CO is contained in hydrogen as a fuel, the CO is adsorbed on the electrode catalyst (Pt) of the fuel cell, the catalyst is deteriorated, and the output is reduced. The CO remaining in the gas after the above reforming / modification is about 0.5 to 1.0% by volume, but it is necessary to set the CO to 10 ppm or less from the viewpoint of preventing poisoning deterioration of the electrode catalyst. .

ＣＯが含まれる水素からＣＯを除去する技術としては、改質ガスに少量の空気を導入して、該空気中の酸素とＣＯを選択的に反応させる選択酸化（ＰＲＯＸ）技術が知られている。本技術は家庭用燃料電池システムなどに採用されているが、空気の導入によりＣＯだけではなく、改質ガス中のＨ２の一部も酸化し消費される点や、改質ガス中に空気に由来する窒素が混入する点、さらに家庭用燃料電池では発電に使用される燃料水素として改質ガスからＣＯのみを除いたものを使用するのが一般的であることから、水素濃度７０容量％程度の燃料水素を用いて発電するために発電効率が十分ではないという課題がある。 As a technique for removing CO from hydrogen containing CO, a selective oxidation (PROX) technique is known in which a small amount of air is introduced into a reformed gas and oxygen and CO in the air are selectively reacted. . This technology is used in household fuel cell systems, etc., but not only CO but also part of H 2 in the reformed gas is oxidized and consumed by the introduction of air. In addition, it is common to use nitrogen that is derived from reformed gas except for CO as the fuel hydrogen used for power generation in household fuel cells. There is a problem that power generation efficiency is not sufficient to generate power using a certain amount of fuel hydrogen.

そこで、本発明者らは、ＣＯ吸着剤と水素吸蔵合金を組み合わせて利用した、改質ガスからの高純度水素の精製技術（ＣＯＡ−ＭＩＢプロセス；ＣＯ Ａｄｓｏｒｐｔｉｏｎ−Ｍｅｔａｌ Ｉｎｔｅｒｍｅｄｉａｔｅ Ｂｕｆｆｅｒ）を開発し、既に特許出願を行った（特許文献１参照）。本精製技術は、ＣＯ吸着剤を用いて改質ガス中のＣＯを水素吸蔵合金の前段で除去することで、該水素吸蔵合金のＣＯによる被毒を回避し、高い水素回収率が得られるという特徴を有する。本精製技術を燃料電池システムに採用することにより純水素型の高い電池発電効率が得られ、水素吸蔵合金に貯蔵した水素を燃料電池の必要水素量に対応して放出することで、電気負荷変動に対応可能な燃料電池システムを構築することが可能となった。   Therefore, the present inventors have developed a technology for purifying high-purity hydrogen from reformed gas (COA-MIB process; CO Adsorption-Metal Intermediate Buffer) using a combination of a CO adsorbent and a hydrogen storage alloy. A patent application was filed (see Patent Document 1). This refining technology uses CO adsorbent to remove CO in the reformed gas at the front stage of the hydrogen storage alloy, thereby avoiding poisoning of the hydrogen storage alloy by CO and obtaining a high hydrogen recovery rate. Has characteristics. By adopting this refining technology in the fuel cell system, high power generation efficiency of pure hydrogen type is obtained, and the electric load fluctuations are released by releasing the hydrogen stored in the hydrogen storage alloy according to the required amount of hydrogen in the fuel cell. It has become possible to build a fuel cell system that can handle the above.

上記ＣＯＡ−ＭＩＢプロセスは、燃料電池システムの効率を向上させるのに非常に有効であるが、ＣＯ吸着剤によるＣＯ吸着除去部および水素吸蔵合金による水素分離回収部の各々で水素回収のロスが発生するため、プロセス全体の水素回収率（水素収率）は８５％程度に留まっており、さらなる水素収率の向上が求められていた。   The COA-MIB process is very effective in improving the efficiency of the fuel cell system, but there is a loss of hydrogen recovery in each of the CO adsorption / removal unit using the CO adsorbent and the hydrogen separation / recovery unit using the hydrogen storage alloy. Therefore, the hydrogen recovery rate (hydrogen yield) of the entire process remains at about 85%, and further improvement of the hydrogen yield has been demanded.

特開２００６−３４２０１４JP 2006-342014 A

そこで本発明の目的は、ＣＯ吸着剤と水素吸蔵合金を組み合わせて利用し、改質ガスから高純度水素を精製するプロセスにおいて、水素収率をさらに高めうる高純度水素の製造方法を提供することにある。   Accordingly, an object of the present invention is to provide a method for producing high-purity hydrogen that can further increase the hydrogen yield in a process of purifying high-purity hydrogen from reformed gas using a combination of a CO adsorbent and a hydrogen storage alloy. It is in.

請求項１に記載の発明は、ＣＯ吸着剤を充填してなるＣＯ吸着塔を１または複数有するＣＯ除去器と、その後段に、水素吸蔵材料を充填した水素吸蔵材料容器を１または複数有する水素分離回収装置を備えた高純度水素製造装置を用いて、ＣＯを含有する水素リッチガス（以下、「ＣＯ含有水素リッチガス」という。）から高純度水素を製造する方法であって、前記ＣＯ含有水素リッチガスを前記ＣＯ除去器でＣＯを除去してＣＯ除去ガスを得るＣＯ吸着除去工程と、前記ＣＯ除去ガスに含まれる水素を前記水素吸蔵材料に吸蔵させた後、この吸蔵された水素を前記吸蔵材料から放出させることにより高純度水素を得る水素分離回収工程とを備え、前記水素分離回収工程は、各水素吸蔵材料容器について、少なくとも、前記ＣＯ除去ガスに含まれる水素を前記水素吸蔵材料に吸蔵させる水素吸蔵ステップと、この吸蔵された水素を前記吸蔵材料から放出させる水素放出ステップとを含むものであり、前記水素分離回収工程は、各水素吸蔵材料容器について、少なくとも、前記ＣＯ除去ガスに含まれる水素を前記水素吸蔵材料に吸蔵させる水素吸蔵ステップと、この吸蔵された水素を前記吸蔵材料から放出させる水素放出ステップとを含むものであり、前記ＣＯ吸着除去工程は、各ＣＯ吸着塔について、前記ＣＯ含有水素リッチガスを流通させてＣＯを吸着除去しＣＯ除去ガスを得るＣＯ吸着ステップと、ＣＯを実質的に含まないガス（以下、「ＣＯ非含有ガス」という。）を導入して当該ＣＯ吸着塔内に滞留したＣＯ除去ガスを排気して前記水素放出ステップ以外のステップにある水素吸蔵材料容器内に放出する雰囲気置換ステップと、前記ＣＯ非含有ガスを流通させつつＣＯ吸着剤を再生するＣＯ吸着剤再生ステップと、をその順序で繰り返すものである、ことを特徴とする高純度水素製造方法である。   The invention described in claim 1 is a hydrogen removing apparatus having one or more CO adsorption towers filled with a CO adsorbent and one or more hydrogen storage material containers filled with a hydrogen storage material in the subsequent stage. A method for producing high-purity hydrogen from a hydrogen-rich gas containing CO (hereinafter referred to as “CO-containing hydrogen-rich gas”) using a high-purity hydrogen production apparatus equipped with a separation and recovery device, the CO-containing hydrogen-rich gas A CO adsorption / removal step of removing CO with the CO remover to obtain a CO removal gas, and storing the hydrogen contained in the CO removal gas in the hydrogen storage material, and then storing the stored hydrogen in the storage material A hydrogen separation and recovery step for obtaining high-purity hydrogen by releasing from the hydrogen, and the hydrogen separation and recovery step includes at least the CO removal gas for each hydrogen storage material container. A hydrogen storage step for storing the hydrogen to be stored in the hydrogen storage material, and a hydrogen release step for releasing the stored hydrogen from the storage material, wherein the hydrogen separation and recovery step is performed for each hydrogen storage material container. A hydrogen storage step for storing at least hydrogen contained in the CO removal gas in the hydrogen storage material; and a hydrogen release step for releasing the stored hydrogen from the storage material, wherein the CO adsorption removal is performed. The process includes, for each CO adsorption tower, a CO adsorption step in which the CO-containing hydrogen rich gas is circulated to adsorb and remove CO to obtain a CO removal gas, and a gas substantially free of CO (hereinafter referred to as “CO-free gas”). And the CO removal gas staying in the CO adsorption tower is exhausted to be in a step other than the hydrogen release step. An atmosphere replacement step for discharging into the oxygen storage material container and a CO adsorbent regeneration step for regenerating the CO adsorbent while circulating the CO-free gas are repeated in that order. This is a method for producing pure hydrogen.

請求項２に記載の発明は、前記雰囲気置換ステップにおいて、前記ＣＯ非含有ガスとして、前記水素吸蔵材料容器から排出される、前記水素吸蔵ステップで吸蔵されなかったオフガスを用いるに際し、前記ＣＯ吸着塔内の雰囲気圧力を該オフガスの圧力より低下させてから該オフガスを当該ＣＯ吸着塔内に流通させる請求項１に記載の高純度水素製造方法である。   The invention according to claim 2 is characterized in that, in the atmosphere replacement step, when the off gas discharged from the hydrogen storage material container and not stored in the hydrogen storage step is used as the CO-free gas, the CO adsorption tower The high-purity hydrogen production method according to claim 1, wherein the off-gas is circulated in the CO adsorption tower after the atmospheric pressure in the inside is lowered below the pressure of the off-gas.

請求項３に記載の発明は、前記ＣＯ吸着剤が、シリカ、アルミナ、活性炭、グラファイトおよびポリスチレン系樹脂よりなる群から選択される１種以上の担体に、ハロゲン化銅（Ｉ）および／またはハロゲン化銅（II）を担持させた材料であることを特徴とする請求項１または２に記載の高純度水素製造方法である。   According to a third aspect of the present invention, the CO adsorbent is applied to one or more carriers selected from the group consisting of silica, alumina, activated carbon, graphite, and polystyrene-based resin, with copper (I) halide and / or halogen. 3. The high-purity hydrogen production method according to claim 1, wherein the high-purity hydrogen production method is a material supporting copper (II).

本発明によれば、ＣＯ吸着剤を用いたＣＯ吸着除去工程における、ＣＯ吸着ステップからＣＯ吸着剤再生ステップへの切り替えのところに、ＣＯ非含有ガスを導入してＣＯ吸着塔内に滞留したＣＯ除去ガスを排気して水素放出ステップ以外のステップ（例えば、水素吸蔵ステップ）にある水素吸蔵材料容器内に放出する雰囲気置換ステップを設けたことで、ＣＯ吸着除去工程における水素回収ロスを低減できるとともに、水素吸蔵合金を用いた水素分離回収工程における水素回収ロスも低減できるようになり、プロセス全体の水素収率をさらに向上させることが可能となった。   According to the present invention, in the CO adsorption removal process using the CO adsorbent, the CO-free gas is introduced and the CO stayed in the CO adsorption tower at the switching from the CO adsorption step to the CO adsorbent regeneration step. By providing an atmosphere replacement step for exhausting the removed gas and releasing it into the hydrogen storage material container in a step other than the hydrogen release step (for example, hydrogen storage step), it is possible to reduce hydrogen recovery loss in the CO adsorption removal process The hydrogen recovery loss in the hydrogen separation and recovery process using the hydrogen storage alloy can be reduced, and the hydrogen yield of the entire process can be further improved.

実施形態に係る高純度水素製造プロセスを示すフロー図である。It is a flowchart which shows the high purity hydrogen manufacturing process which concerns on embodiment. 実施形態における、ＣＯ吸着塔１基ごとの運転パターンを説明するためのフロー図である。It is a flowchart for demonstrating the driving | operation pattern for every CO adsorption tower in embodiment. 実施形態に係る、ＣＯ除去器における運転パターンの切り替え操作を説明するためのフロー図である。It is a flowchart for demonstrating operation pattern switching operation in the CO remover based on Embodiment.

以下、本発明の実施の形態について図面を参照しつつ詳細に説明する。なお以下の実施形態においては、ＣＯ含有水素リッチガス（以下、単に「水素リッチガス」ともいう。）として、炭化水素含有燃料を水蒸気で改質した後に変成させたガス（以下、「変成ガス」という。）を代表例に挙げて説明する。   Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, as a CO-containing hydrogen-rich gas (hereinafter, also simply referred to as “hydrogen-rich gas”), a gas obtained by reforming a hydrocarbon-containing fuel after reforming with steam (hereinafter referred to as “modified gas”). ) As a representative example.

〔実施形態〕
実施形態の一例を図１のフロー図に示す。本実施形態では、ＣＯ吸着剤の吸着／再生の切り替え操作を雰囲気圧力の昇降（すなわち、圧力スイング）で行い、水素吸蔵材料の水素吸蔵／水素放出の切り替え操作を雰囲気圧力の昇降（圧力スイング）に加えて反応温度の昇降（すなわち、温度スイング）により行う例を示す。 Embodiment
An example of the embodiment is shown in the flowchart of FIG. In this embodiment, the adsorption / regeneration switching operation of the CO adsorbent is performed by increasing / decreasing the atmospheric pressure (that is, pressure swing), and the switching operation of hydrogen storage / hydrogen release of the hydrogen storage material is performed by increasing / decreasing the atmospheric pressure (pressure swing). In addition to the above, an example is shown in which the reaction temperature is raised and lowered (ie, temperature swing).

（改質・変成工程）
ＣＯ含有水素リッチガスとしての変成ガスを製造するための改質・変成工程には、例えば通常用いられる水蒸気改質器と変成器（いずれも図示せず）との組合せ（「改質・変成器」と総称する。）を用いればよい。改質器において天然ガス等の炭化水素含有燃料を水蒸気で改質してＨ２およびＣＯを主成分とする改質ガスとした後、変成器においてこの改質ガスにさらに水蒸気を添加して変成しＨ２を主成分とする（水素リッチな）変成ガスＢを生成する。この変成ガスＢ中には、Ｈ２の他、ＣＯ２、少量のＣＨ４、Ｈ２Ｏなどとともに、０．５容積％（以下、単に「％」と表示する。）程度のＣＯが残留している。 (Reformation / transformation process)
In the reforming / transformation process for producing the shift gas as the CO-containing hydrogen-rich gas, for example, a combination of a normally used steam reformer and a shifter (both not shown) (“reformer / transformer”) May be used collectively). In a reformer, a hydrocarbon-containing fuel such as natural gas is reformed with steam to form a reformed gas mainly composed of H 2 and CO, and then the steam is further added to the reformed gas in the reformer. Then, the modified gas B mainly composed of H 2 (hydrogen-rich) is generated. In this modified gas B, in addition to H 2 , CO of about 0.5 volume% (hereinafter simply referred to as “%”) remains along with CO 2 , a small amount of CH 4 , H 2 O, and the like. ing.

（ＣＯ吸着除去工程）
本実施形態のＣＯ吸着除去工程には、ＣＯ吸着剤を充填したＣＯ吸着塔２基（２ａ，２ｂ）からなるＣＯ除去器２を用いる。以下、ＣＯ吸着塔１基ごとの運転パターンについて図２を参照しつつ説明した後、さらにＣＯ除去器２（ＣＯ吸着塔２基）における運転パターンの切り替え操作について図３を参照しつつ説明する。 (CO adsorption removal process)
In the CO adsorption removal process of the present embodiment, a CO remover 2 composed of two CO adsorption towers (2a, 2b) filled with a CO adsorbent is used. Hereinafter, the operation pattern for each CO adsorption tower will be described with reference to FIG. 2, and the operation pattern switching operation in the CO remover 2 (two CO adsorption towers) will be further described with reference to FIG.

〔ＣＯ吸着塔１基ごとの運転パターン〕
ＣＯ吸着塔としては代表として２ａに着目し、図２を参照しつつ説明を行う。 [Operation pattern for each CO adsorption tower]
The CO adsorption tower will be described with reference to FIG. 2 while focusing on 2a as a representative.

［ＣＯ吸着除去ステップ］（図２（ａ）参照）：変成ガスＢを熱交換器（図示せず）等でＣＯ吸着反応に適した温度（例えば４０℃）まで冷却した後、ＣＯ吸着塔２ａを通過させ、変成ガスＢ中のＣＯを選択的に除去する。これによりＣＯ吸着塔２ａ出口からＣＯ除去ガスＣが流出する。変成ガスＢ中のＣＯはＣＯ吸着剤に吸着するが、ＣＯ吸着帯（図中の斜線部）が、ＣＯ吸着塔２ａの出口まで達する（吸着破過する）前にこのＣＯ吸着除去ステップを終了する。 [CO Adsorption Removal Step] (see FIG. 2A): The modified gas B is cooled to a temperature (for example, 40 ° C.) suitable for the CO adsorption reaction with a heat exchanger (not shown), and then the CO adsorption tower 2a. And CO in the modified gas B is selectively removed. Thereby, the CO removal gas C flows out from the CO adsorption tower 2a outlet. CO in the metamorphic gas B is adsorbed by the CO adsorbent, but this CO adsorption removal step is completed before the CO adsorption zone (shaded area in the figure) reaches the outlet of the CO adsorption tower 2a (adsorption breakthrough). To do.

ＣＯ吸着剤としては、シリカ、アルミナ、活性炭、グラファイトおよびポリスチレン系樹脂よりなる群から選択される１種以上の担体に、ハロゲン化銅（Ｉ）またはハロゲン化銅（II）を担持させた材料を用いるのが特に推奨される。このようなハロゲン化銅を担持させたＣＯ吸着剤は、ゼオライトモレキュラーシーブス、カーボンモレキュラーシーブス、活性炭、または活性アルミナといった従来の吸着剤に比べ数倍の吸着性能を発揮するため、ＣＯ吸着塔２ａが大幅に小型化できる。ＣＯ吸着剤によるＣＯ吸着反応はＣＯ分圧が高いほどＣＯ吸着容量が増大すること、および水素吸蔵材料はＨ２分圧が高いほど水素吸蔵量が増大するため、ＣＯ吸着除去ステップおよび水素吸蔵ステップにおいては、雰囲気圧力を常圧より高めるのが好ましい。そこで、上記改質・変成器とＣＯ除去器２（ＣＯ吸着塔２ａ）の間に昇圧器（図示せず）を設け、変成ガスＢを例えば０．９ＭＰａに昇圧してＣＯ吸着塔２ａを通過させてＣＯを除去し、ＣＯ除去ガスＣをそのまま水素分離回収装置３に導入してＨ２を吸蔵させるようにするとよい。 As the CO adsorbent, a material in which copper (I) halide or copper (II) halide is supported on one or more carriers selected from the group consisting of silica, alumina, activated carbon, graphite, and polystyrene resin. It is particularly recommended to use it. Such a CO adsorbent carrying copper halide exhibits adsorption performance several times that of conventional adsorbents such as zeolite molecular sieves, carbon molecular sieves, activated carbon, or activated alumina. The size can be greatly reduced. In the CO adsorption reaction by the CO adsorbent, the CO adsorption capacity increases as the CO partial pressure increases, and the hydrogen storage amount of the hydrogen storage material increases as the H 2 partial pressure increases. In this case, it is preferable to increase the atmospheric pressure from the normal pressure. Therefore, a booster (not shown) is provided between the reformer / transformer and the CO remover 2 (CO adsorption tower 2a), and the transformed gas B is pressurized to, for example, 0.9 MPa and passed through the CO adsorption tower 2a. The CO is removed, and the CO removal gas C is introduced as it is into the hydrogen separation / recovery device 3 to occlude H 2 .

［雰囲気置換ステップ］（図２（ｂ）参照）：上記ＣＯ吸着除去ステップが終了したＣＯ吸着塔２ａは、その塔内に充填されたＣＯ吸着剤の吸着性能を維持するために、ＣＯ吸着剤の再生を行う必要があるが、それに先立ち、該ＣＯ吸着塔２ａ内にその入口からＣＯ非含有ガスＦを導入して該ＣＯ吸着塔２ａ内に滞留した、水素を含むＣＯ除去ガスＣ’を塔外に排出し該ＣＯ非含有ガスＦと置換する。この操作により、水素を含むＣＯ除去ガスＣ’を、製品水素を回収するため水素吸蔵材料容器に送ることが可能となり、減圧排気操作による水素ロス（ＣＯ除去ガスＣ’中に含まれる水素のロス）が低減できる。本置換操作によりＣＯ吸着帯が上記ＣＯ吸着除去ステップ終了時よりもさらに出口側に移動する。ＣＯ吸着塔２ａは、本ステップでＣＯ吸着帯が塔の出口まで達しない（破過しない）ように設計を行う必要がある。該ＣＯ吸着塔２ａから排出された該ＣＯ除去ガスＣ’は、後記の水素吸蔵準備ステップにある水素吸蔵材料容器（本例では図１中の符号３ｃ）内に導入する。ＣＯ非含有ガスＦとしては、ＣＯを実質的に含まないだけでなく、上記ＣＯ除去ガスＣ中のＨ２を消費しないためにＯ２をも実質的に含まないものであればどのようなガスも使用可能であり、例えば、窒素ガスや二酸化炭素ガス、アルゴンガスなどの不活性ガスの他、後記の水素吸蔵ステップで吸蔵されないオフガス（図１中の符号Ｅ）などが好適に利用できる。 [Atmosphere replacement step] (see FIG. 2 (b)): The CO adsorption tower 2a after the CO adsorption removal step is completed is in order to maintain the adsorption performance of the CO adsorbent packed in the tower. However, prior to this, the CO removal gas C ′ containing hydrogen, which is retained in the CO adsorption tower 2a by introducing the CO-free gas F from the inlet into the CO adsorption tower 2a, is introduced. It is discharged outside the column and replaced with the CO-free gas F. By this operation, it becomes possible to send the CO removal gas C ′ containing hydrogen to the hydrogen storage material container in order to recover the product hydrogen, and hydrogen loss (loss of hydrogen contained in the CO removal gas C ′) due to the decompression exhaust operation. ) Can be reduced. By this replacement operation, the CO adsorption zone moves further to the outlet side than at the end of the CO adsorption removal step. The CO adsorption tower 2a needs to be designed so that the CO adsorption zone does not reach the outlet of the tower (does not break through) in this step. The CO removal gas C ′ discharged from the CO adsorption tower 2a is introduced into a hydrogen storage material container (in this example, reference numeral 3c in FIG. 1) in a hydrogen storage preparation step described later. The CO-free gas F may be any gas that does not substantially contain CO but does not substantially contain O 2 in order not to consume H 2 in the CO removal gas C. For example, in addition to an inert gas such as nitrogen gas, carbon dioxide gas, and argon gas, off-gas that is not occluded in the hydrogen occlusion step (reference numeral E in FIG. 1) can be suitably used.

ここで、上記特許文献１に記載の従来技術では、ＣＯ非含有ガスとの置換でＣＯ吸着塔から排出されたＣＯ除去ガスは、改質器などの加熱燃料として有効利用されるものの、このＣＯ除去ガス中のＨ２は、燃料水素としての水素としては回収されず、プロセス全体の水素回収率には寄与していなかった。 Here, in the prior art described in Patent Document 1, the CO removal gas discharged from the CO adsorption tower by substitution with a CO-free gas is effectively used as a heating fuel for a reformer or the like. H 2 in the removed gas was not recovered as hydrogen as fuel hydrogen, and did not contribute to the hydrogen recovery rate of the entire process.

これに対し、本発明では、上述のとおり、ＣＯ非含有ガスＦとの置換でＣＯ吸着塔２ａから排出されたＣＯ除去ガスＣ’は、後記の水素吸蔵準備ステップにある水素吸蔵材料容器３ａ内に導入されるので、該ＣＯ除去ガス中のＨ２は、該水素吸蔵材料容器３ａ内の水素吸蔵合金に吸蔵され、その後の水素放出ステップで燃料水素として有効に利用される。したがって、本発明により、ＣＯ吸着除去ステップとＣＯ吸着剤との切り替えの際における水素回収のロスが確実に低減されることとなる。 On the other hand, in the present invention, as described above, the CO removal gas C ′ discharged from the CO adsorption tower 2a by the substitution with the CO-free gas F is stored in the hydrogen storage material container 3a in the hydrogen storage preparation step described later. Therefore, H 2 in the CO removal gas is occluded by the hydrogen occlusion alloy in the hydrogen occlusion material container 3a, and is effectively used as fuel hydrogen in the subsequent hydrogen release step. Therefore, according to the present invention, the loss of hydrogen recovery at the time of switching between the CO adsorption removal step and the CO adsorbent is reliably reduced.

［減圧ステップ］（図２（ｃ）参照）：上記雰囲気置換ステップの終了後、ＣＯ吸着剤の再生を行うが、そのために先ずＣＯ吸着塔２ａ内の減圧操作を行い、その後、該ＣＯ吸着塔２ａ内にＣＯ非含有ガスＦを流通させてＣＯ吸着剤の洗浄操作を行う。 [Decompression step] (see FIG. 2 (c)): After completion of the atmosphere replacement step, the CO adsorbent is regenerated. For this purpose, first, the depressurization operation in the CO adsorption tower 2a is performed, and then the CO adsorption tower. A CO-free gas F is circulated in 2a to perform a CO adsorbent cleaning operation.

ＣＯ吸着塔２ａ内を減圧することで、該吸着塔２ａ内の雰囲気ガス中に残留するＣＯと、ＣＯ吸着剤に吸着したＣＯの、各一部をＣＯ吸着塔２ａ外に排出する。減圧操作は常圧までの減圧でもよいが、さらに常圧から負圧まで真空引きすることで、雰囲気ガス中の残留ＣＯと、ＣＯ吸着剤への吸着ＣＯの、より多くをＣＯ吸着塔２ａ外に排出することができる。   By depressurizing the inside of the CO adsorption tower 2a, a part of CO remaining in the atmospheric gas in the adsorption tower 2a and CO adsorbed by the CO adsorbent is discharged out of the CO adsorption tower 2a. The depressurization operation may be performed under normal pressure, but by further evacuation from normal pressure to negative pressure, the residual CO in the atmospheric gas and the adsorbed CO to the CO adsorbent can be more out of the CO adsorption tower 2a. Can be discharged.

［ＣＯ吸着剤再生ステップ］（図２（ｄ）参照）：上記減圧ステップにおける減圧操作の後、ＣＯ非含有ガスＦを所定流量で所定時間流通させて洗浄することで、上記減圧操作で除去し切れなかったＣＯが除去され、ＣＯ吸着剤が再生される。 [CO adsorbent regeneration step] (see FIG. 2 (d)): After the depressurization operation in the depressurization step, the CO-free gas F is removed by the depressurization operation by flowing and washing at a predetermined flow rate for a predetermined time. The uncut CO is removed and the CO adsorbent is regenerated.

［昇圧ステップ］（図２（ｅ）参照）：上記ＣＯ吸着剤再生ステップにおける洗浄操作によりＣＯ吸着剤の再生が完了した後、再び水素吸蔵ステップに移行させるために次ステップとしての昇圧ステップにおいて昇圧操作を行うが、この昇圧操作は、低圧のＣＯ吸着塔２ａ内に高圧の変成ガスＢを導入してＣＯ吸着塔２ａ内の圧力が所定圧力に達するように行う。 [Pressure increase step] (see FIG. 2 (e)): After the regeneration of the CO adsorbent is completed by the cleaning operation in the CO adsorbent regeneration step, the pressure is increased in the pressure increase step as the next step in order to shift again to the hydrogen storage step. The pressure increase operation is performed so that the high-pressure modified gas B is introduced into the low-pressure CO adsorption tower 2a so that the pressure in the CO adsorption tower 2a reaches a predetermined pressure.

〔ＣＯ吸着塔２基における運転パターンの切り替え操作〕
各ＣＯ吸着塔２ａ，２ｂにつき、ＣＯ吸着除去ステップ→雰囲気置換ステップ→減圧ステップ→ＣＯ吸着剤再生ステップ→昇圧ステップ→ＣＯ吸着除去ステップの順序でこのサイクルを繰り返すように各ステップを順次切り替える必要があるが、連続的に高純度水素を製造するためには（すなわち、連続的にＣＯ除去ガスＣを得るためには）、２塔２ａ，２ｂのうちいずれか１塔は常にＣＯ吸着除去ステップとしておく必要がある。 [Operation pattern switching operation in 2 CO adsorption towers]
For each CO adsorption tower 2a, 2b, it is necessary to sequentially switch each step so that this cycle is repeated in the order of CO adsorption removal step → atmosphere replacement step → depressurization step → CO adsorbent regeneration step → pressure increase step → CO adsorption removal step. However, in order to continuously produce high-purity hydrogen (that is, to obtain CO removal gas C continuously), one of the two towers 2a and 2b is always used as a CO adsorption removal step. It is necessary to keep.

このためには、例えば、ＣＯ吸着塔２ａで昇圧ステップ→ＣＯ吸着除去ステップを行っている間に、ＣＯ吸着塔２ｂで雰囲気置換ステップ→減圧ステップ→ＣＯ吸着剤再生ステップを行い、次に、ＣＯ吸着塔２ａで雰囲気置換ステップ→減圧ステップ→ＣＯ吸着剤再生ステップを行っている間に、ＣＯ吸着塔２ａで昇圧ステップ→ＣＯ吸着除去ステップを行うというように、いずれか１塔は常時ＣＯ吸着除去ステップを行っているようにサイクルを繰り返すことで連続的に変成ガスＢをＣＯ除去ガスＣに精製処理することができる。   For this purpose, for example, while the pressure increasing step → CO adsorption removing step is performed in the CO adsorption tower 2a, the atmosphere replacement step → pressure reducing step → CO adsorbent regeneration step is performed in the CO adsorption tower 2b, and then the CO adsorbent regeneration step is performed. While the adsorption tower 2a is performing the atmosphere replacement step → depressurization step → CO adsorbent regeneration step, one of the towers always performs CO adsorption removal, such as the pressure increase step → CO adsorption removal step in the CO adsorption tower 2a. By repeating the cycle as if performing the step, it is possible to continuously purify the modified gas B into the CO removal gas C.

ここで、図３を参照しつつ、代表としてＣＯ吸着塔２ａに着目し、上記各ステップの具体的な切り替え操作方法を説明する。先ず、昇圧ステップにおいては、バルブＶ０１を開き、バルブＶ０７、Ｖ０８を閉じてＣＯ吸着塔２ａ内に高圧の変成ガスＢ’を導入することで、所定圧力までの昇圧が行われる。所定圧力に到達した後は、バルブＶ０７を開くことで、ＣＯ吸着除去ステップに移行し、ＣＯ吸着塔２ａの出口から圧力調整弁Ｖ１１を介してＣＯ除去ガスＣが連続的に得られる。   Here, with reference to FIG. 3, focusing on the CO adsorption tower 2 a as a representative, a specific switching operation method for each step will be described. First, in the pressure increasing step, the valve V01 is opened, the valves V07 and V08 are closed, and the high-pressure modified gas B 'is introduced into the CO adsorption tower 2a, whereby the pressure is increased to a predetermined pressure. After reaching the predetermined pressure, the valve V07 is opened to shift to the CO adsorption removal step, and the CO removal gas C is continuously obtained from the outlet of the CO adsorption tower 2a via the pressure adjustment valve V11.

ＣＯ吸着除去ステップの終了後は、バルブＶ０１を閉じ、バルブＶ０３を開けて、ＣＯ非含有ガスＦをＣＯ吸着塔２ａ内に導入することで、雰囲気置換ステップに移行し、塔内の雰囲気がＣＯ除去ガスＣ’からＣＯ非含有ガスＦに置換される。   After completion of the CO adsorption removal step, the valve V01 is closed, the valve V03 is opened, and the CO-free gas F is introduced into the CO adsorption tower 2a, so that the process proceeds to the atmosphere replacement step, and the atmosphere in the tower is changed to CO. The removed gas C ′ is replaced with the CO-free gas F.

雰囲気置換ステップの終了後は、バルブＶ０７、Ｖ０３を閉じ、バルブＶ０２、Ｖ２９を開けることで、減圧ステップに移行し、ＣＯ吸着塔２ａ内が常圧まで減圧される。さらに負圧まで減圧する場合は、バルブＶ２９を閉じ、バルブＶ３０を開け、真空ポンプ７を稼動することで、ＣＯ吸着塔２ａ内が負圧まで減圧される。   After the atmosphere replacement step is completed, the valves V07 and V03 are closed and the valves V02 and V29 are opened, so that the process proceeds to the pressure reducing step, and the inside of the CO adsorption tower 2a is decompressed to normal pressure. When the pressure is further reduced to a negative pressure, the valve V29 is closed, the valve V30 is opened, and the vacuum pump 7 is operated, whereby the inside of the CO adsorption tower 2a is reduced to a negative pressure.

減圧ステップの終了後は、バルブＶ０８、Ｖ２５を開け、洗浄ガスとしてのＣＯ非含有ガスＦをＣＯ吸着塔２ａ内にその出口から入口に向かって流通させることで、ＣＯ吸着剤の洗浄、再生が行われる。   After the decompression step is completed, the valves V08 and V25 are opened, and the CO-free gas F as the cleaning gas is circulated in the CO adsorption tower 2a from the outlet toward the inlet, thereby cleaning and regeneration of the CO adsorbent. Done.

（水素分離回収工程）
図１に戻り、本実施形態の水素分離回収工程には、水素吸蔵材料を充填した水素吸蔵材料容器３個（３ａ，３ｂ，３ｃ）からなる水素分離回収装置３を用いる。以下、水素吸蔵材料容器１個ごとの運転パターンについて説明した後、さらに水素分離回収装置３（水素吸蔵材料容器３個）における運転パターンの切り替え操作について説明する。 (Hydrogen separation and recovery process)
Returning to FIG. 1, in the hydrogen separation and recovery process of the present embodiment, a hydrogen separation and recovery device 3 including three hydrogen storage material containers (3a, 3b, and 3c) filled with a hydrogen storage material is used. Hereinafter, after describing the operation pattern for each hydrogen storage material container, the operation pattern switching operation in the hydrogen separation and recovery device 3 (three hydrogen storage material containers) will be described.

〔水素吸蔵材料容器１個ごとの運転パターン〕
水素吸蔵材料容器としては代表として３ａに着目し、図２を参照しつつ説明を行う。 [Operation pattern for each hydrogen storage material container]
As a representative hydrogen storage material container, attention will be paid to 3a, and description will be made with reference to FIG.

［水素吸蔵ステップ］：ＣＯ除去ガスＣを水素吸蔵材料を充填した水素吸蔵材料容器３ａを通過させ、ＣＯ除去ガスＣ中のＨ２を選択的に吸蔵する。水素吸蔵材料としては、水素吸蔵合金が適しており、さらに水素吸蔵合金に表面処理を施したものは、ＣＯによる被毒を十分に抑制しうるためより好ましい。水素吸蔵合金の表面処理としては、ＣＯ２やＨ２Ｏ、ＣＯに対して耐久性を有するものであれば特に限定されるものではないが、例えばフッ化処理が挙げられる。水素吸蔵材料による水素吸収反応は温度が低いほど促進されるため、前工程から排出されたＣＯ除去ガスＣを例えば水冷ジャケットで冷却して導入するのが好ましい。 [Hydrogen storage step]: The CO removal gas C is passed through the hydrogen storage material container 3a filled with the hydrogen storage material, and H 2 in the CO removal gas C is selectively stored. As the hydrogen storage material, a hydrogen storage alloy is suitable, and a material obtained by subjecting the hydrogen storage alloy to surface treatment is more preferable because poisoning by CO can be sufficiently suppressed. The surface treatment of the hydrogen storage alloy is not particularly limited as long as it has durability against CO 2 , H 2 O, and CO, and examples thereof include fluorination treatment. Since the hydrogen absorption reaction by the hydrogen storage material is promoted as the temperature is lower, it is preferable to introduce the CO removal gas C discharged from the previous process by cooling it with a water cooling jacket, for example.

水素吸蔵材料に吸収されなかったＨ２以外のガスはオフガスＥとなるが、このオフガスＥは、ＣＯ２が主成分で、微量のＣＨ４を含むものの、ＣＯおよびＯ２を含まないため、ＣＯ非含有ガスＦとしてＣＯ吸着塔の雰囲気置換ガスやＣＯ吸着剤の洗浄ガスとして用いることができる。このオフガスＥは、バルブＶ１８を開けることで、保圧弁Ｖ２４を介してバッファタンク８に回収される。そして、バッファタンク８に回収されたオフガスＥは、雰囲気置換ガスとして使用する場合には流量調節弁２８を介して雰囲気置換ステップにあるＣＯ吸着塔内に、洗浄ガスとして使用する場合には流量調節弁２５を介してＣＯ吸着除去ステップにあるＣＯ吸着塔内に、それぞれ導入される。 Gases other than H 2 that have not been absorbed by the hydrogen storage material become off-gas E, but this off-gas E contains CO 2 as the main component and contains a small amount of CH 4 , but does not contain CO and O 2 , so CO 2 The non-containing gas F can be used as an atmosphere replacement gas for a CO adsorption tower or a cleaning gas for a CO adsorbent. This off-gas E is recovered in the buffer tank 8 via the pressure holding valve V24 by opening the valve V18. The off-gas E recovered in the buffer tank 8 is supplied to the CO adsorption tower in the atmosphere replacement step via the flow rate control valve 28 when used as the atmosphere replacement gas, and the flow rate is adjusted when used as the cleaning gas. It introduce | transduces into the CO adsorption tower in a CO adsorption removal step through the valve 25, respectively.

［水素放出ステップ］：水素を吸蔵した水素吸蔵材料から水素を放出させる反応は、水素吸収反応とは逆に温度が高いほど促進されるため、水素放出ステップにおける反応温度は、上記水素吸蔵ステップにおける反応温度より高くする。このような条件を満足させるため、例えば後段の燃料電池の冷却排水（８０℃程度の湯）を用いて間接的に水素吸蔵材料を加熱し昇温するようにすればよい。加熱により水素吸蔵材料から放出された水素は、バルブＶ１３および流量調整弁Ｖ２７を介して燃料電池に供給される。ただし、加熱処理中に放出される水素には、前ステップ（水素吸蔵ステップ）の終了時点で水素吸蔵材料容器内に残留しているＣＯ２等が混入し、水素の純度が高くないため、バルブＶ１９を介して系外に放出し、改質器の加熱用燃料などとして有効利用すればよい。 [Hydrogen desorption step]: Since the reaction for desorbing hydrogen from the hydrogen occlusion material that occludes hydrogen is accelerated as the temperature increases, the reaction temperature in the hydrogen desorption step is the same as that in the hydrogen occlusion step. Above the reaction temperature. In order to satisfy such conditions, for example, the hydrogen storage material may be heated indirectly by using the cooling drainage (hot water of about 80 ° C.) of the subsequent fuel cell. Hydrogen released from the hydrogen storage material by heating is supplied to the fuel cell through the valve V13 and the flow rate adjusting valve V27. However, since the hydrogen released during the heat treatment is mixed with CO 2 remaining in the hydrogen storage material container at the end of the previous step (hydrogen storage step), the purity of hydrogen is not high. It may be discharged out of the system via V19 and effectively used as a heating fuel for the reformer.

［水素吸蔵準備ステップ］：既述したように、水素吸蔵材料による水素吸収反応は温度が低いほど促進されるため、前段のＣＯ除去器２（ＣＯ吸着塔）から排出されたＣＯ除去ガスＣを例えば常温の工業用水を用いた水冷ジャケットで冷却して導入し、前ステップ（水素放出ステップ）で加熱された水素吸蔵材料を冷却する。 [Hydrogen storage preparation step]: As described above, since the hydrogen absorption reaction by the hydrogen storage material is accelerated as the temperature is lower, the CO removal gas C discharged from the preceding CO remover 2 (CO adsorption tower) is reduced. For example, it cools and introduce | transduces with the water-cooling jacket which uses the industrial water of normal temperature, and cools the hydrogen storage material heated by the front step (hydrogen discharge | release step).

また、上記〔ＣＯ吸着塔１基ごとの運転パターン〕の［ＣＯ吸着除去ステップ］のところで既述したように、水素吸蔵材料はＨ２分圧が高いほど水素吸蔵量が増大するため、次ステップの水素吸蔵ステップにおいては、雰囲気圧力を常圧より高めるのが好ましいが、本水素吸蔵準備ステップにて、高圧のＣＯ除去ガスＣを水素吸蔵材料容器３ａに導入することで、自動的に雰囲気圧力を高めることができる。 Further, as described above in [CO adsorption removal step] of [Operation pattern for each CO adsorption tower], the hydrogen storage amount of the hydrogen storage material increases as the H 2 partial pressure increases. In the hydrogen storage step, it is preferable to increase the atmospheric pressure from the normal pressure. However, in this hydrogen storage preparation step, the atmospheric pressure is automatically increased by introducing the high-pressure CO removal gas C into the hydrogen storage material container 3a. Can be increased.

［水素吸蔵容器３個における運転パターンの切り替え操作］：各水素吸蔵材料容器３ａ，３ｂ，３ｃにつき、水素吸蔵ステップ→水素放出ステップ→水素吸蔵準備ステップ→水素吸蔵ステップの順序でこのサイクルを繰り返すように各ステップを順次切り替える必要があるが、連続的に高純度水素を製造するためには、常に、１個の水素吸蔵材料容器は水素吸蔵ステップとし、他の１個の水素吸蔵材料容器は水素放出ステップとし、残りの１個の水素吸蔵材料容器は水素吸蔵準備ステップとしておくとよい。 [Operation of switching operation patterns in three hydrogen storage containers]: For each of the hydrogen storage material containers 3a, 3b, 3c, this cycle is repeated in the order of hydrogen storage step → hydrogen release step → hydrogen storage preparation step → hydrogen storage step. However, in order to continuously produce high-purity hydrogen, one hydrogen storage material container is always a hydrogen storage step, and the other one hydrogen storage material container is a hydrogen storage step. It is good to set it as a discharge | release step and to make the remaining one hydrogen storage material container into a hydrogen storage preparation step.

本実施形態のプロセス構成においては、バッファタンク８に貯められたオフガスＥの圧力は変成ガスＢの圧力より低くなるため、ＣＯ吸着塔（例えば２ｂ）の雰囲気置換ステップの際には、バルブＶ１６を事前に開けて該ＣＯ吸着塔２ｂ内の雰囲気ガス（ＣＯ除去ガスＣ’）を、水素吸蔵準備ステップにある水素吸蔵材料容器（例えば３ｃ）内に放出してＣＯ吸着塔２ｂ内の圧力を下げた後に、バルブＶ２８を開けＣＯ吸着塔２ｂ内の雰囲気ガスの置換を行う。なお、水素吸蔵準備ステップにある水素吸蔵材料容器３ｃ内に放出されたＣＯ除去ガスＣ’中のＨ２は、水素吸蔵合金に吸蔵されるため、次ステップ（水素放出ステップ）の際に燃料電池に供給することができ、水素分離回収装置３での水素の回収ロスは増加しない。 In the process configuration of the present embodiment, the pressure of the off gas E stored in the buffer tank 8 is lower than the pressure of the modified gas B. Therefore, during the atmosphere replacement step of the CO adsorption tower (for example, 2b), the valve V16 is set. Open in advance and release the atmospheric gas (CO removal gas C ′) in the CO adsorption tower 2b into a hydrogen storage material container (for example, 3c) in the hydrogen storage preparation step to lower the pressure in the CO adsorption tower 2b. After that, the valve V28 is opened and the atmospheric gas in the CO adsorption tower 2b is replaced. Since the H 2 in the CO removal gas C ′ released into the hydrogen storage material container 3c in the hydrogen storage preparation step is stored in the hydrogen storage alloy, the fuel cell is used in the next step (hydrogen release step). The hydrogen recovery loss in the hydrogen separation and recovery device 3 does not increase.

したがって、本実施形態のプロセス構成を採用することで、ＣＯ除去器２における水素の回収ロスを効果的に低減できるため、プロセス全体の水素回収率を、従来の８５％程度から９０％程度へと約５ポイント向上させることが可能となる。   Accordingly, by adopting the process configuration of the present embodiment, the hydrogen recovery loss in the CO remover 2 can be effectively reduced, so that the hydrogen recovery rate of the entire process is increased from about 85% to about 90%. It becomes possible to improve about 5 points.

（変形例）
上記実施形態では、ＣＯ吸着除去工程の雰囲気置換ステップにおいて、ＣＯ吸着塔から排気されたＣＯ除去ガスＣ’は、水素吸蔵準備ステップにある水素吸蔵材料容器内のみに放出する例を示したが、水素放出ステップ以外のステップであれば、いずれのステップにある水素吸蔵材料容器内に放出してもよく、水素吸蔵ステップにある水素吸蔵材料容器内のみ、あるいは、水素吸蔵準備ステップにある水素吸蔵材料容器内および水素吸蔵ステップにある水素吸蔵材料容器内の双方に放出することも可能である。 (Modification)
In the above embodiment, in the atmosphere replacement step of the CO adsorption removal process, the CO removal gas C ′ exhausted from the CO adsorption tower has been shown to be released only into the hydrogen storage material container in the hydrogen storage preparation step. As long as it is a step other than the hydrogen release step, it may be released into the hydrogen storage material container in any step, only in the hydrogen storage material container in the hydrogen storage step, or the hydrogen storage material in the hydrogen storage preparation step It is also possible to discharge into both the container and the hydrogen storage material container in the hydrogen storage step.

また、上記実施形態では、水素分離回収工程として、各水素吸蔵材料容器３ａ，３ｂ，３ｃにつき、水素吸蔵ステップ→水素放出ステップ→水素吸蔵準備ステップ→水素吸蔵ステップの順序でこのサイクルを繰り返すように各ステップを順次切り替える例を示したが、少なくとも、水素吸蔵ステップと水素放出ステップとを含めばよく、例えば、水素吸蔵準備ステップを省略して水素吸蔵ステップと水素放出ステップとを交互に切り替えるようにしてもよい。この場合には、ＣＯ吸着除去工程の雰囲気置換ステップにおいて、ＣＯ吸着塔から排気されたＣＯ除去ガスＣ’は、水素吸蔵ステップにある水素吸蔵材料容器内に放出するとよい。   In the above embodiment, as the hydrogen separation / recovery process, this cycle is repeated for each hydrogen storage material container 3a, 3b, 3c in the order of hydrogen storage step → hydrogen release step → hydrogen storage preparation step → hydrogen storage step. Although an example of sequentially switching each step has been shown, it is sufficient to include at least a hydrogen storage step and a hydrogen release step.For example, a hydrogen storage preparation step is omitted and a hydrogen storage step and a hydrogen release step are alternately switched. May be. In this case, in the atmosphere replacement step of the CO adsorption removal process, the CO removal gas C ′ exhausted from the CO adsorption tower may be released into the hydrogen storage material container in the hydrogen storage step.

上記実施形態では、ＣＯ吸着除去工程として２塔のＣＯ吸着塔を順次切り替えて用いる例を示したが、３塔以上のＣＯ吸着塔を順次切り替えて用いてもよい。また、ＣＯ吸着除去工程として単一のＣＯ吸着塔を用い、定期検査時などにＣＯ吸着剤の再生ないし取替えを行うようにしてもよい。   In the above-described embodiment, an example in which two CO adsorption towers are sequentially switched and used as the CO adsorption removal step has been described. However, three or more CO adsorption towers may be sequentially switched and used. In addition, a single CO adsorption tower may be used as the CO adsorption removal process, and the CO adsorbent may be regenerated or replaced during periodic inspections.

また、上記実施形態では、水素分離回収工程として３個の水素吸蔵材料容器を順次切り替えて用いる例を示したが、２個または４個以上の水素吸蔵材料容器を順次切り替えて用いてもよい。また、単一の水素吸蔵材料容器とバッファタンク（上記バッファタンク８とは別のもの）を組み合わせ、該バッファタンクから後段の燃料電池等に連続的に高純度水素を供給しつつ、単一の水素吸蔵材料容器中の水素吸蔵材料により水素の吸蔵と放出とを繰り返しながら、放出時のみバッファタンクに水素を溜めるようにしてもよい。   In the above-described embodiment, an example in which three hydrogen storage material containers are sequentially switched and used as the hydrogen separation and recovery process has been described. However, two or four or more hydrogen storage material containers may be sequentially switched and used. In addition, a single hydrogen storage material container and a buffer tank (separate from the buffer tank 8) are combined, and a single high-purity hydrogen is continuously supplied from the buffer tank to a subsequent fuel cell or the like. Hydrogen may be stored in the buffer tank only during the discharge, while repeating the hydrogen storage and release with the hydrogen storage material in the hydrogen storage material container.

また、上記実施形態では、水素吸蔵材料として、水素吸蔵合金、表面処理した水素吸蔵合金を例示したが、ケミカルハイドライド、カーボンナノチューブ、またはこれらのいずれか２種以上を用いてもよい。   Moreover, in the said embodiment, although the hydrogen storage alloy and the surface-treated hydrogen storage alloy were illustrated as a hydrogen storage material, you may use a chemical hydride, a carbon nanotube, or any 2 or more types of these.

また、上記実施形態では、ＣＯ吸着剤の吸着／再生の切り替え操作を雰囲気圧力の昇降（すなわち、圧力スイング）のみにより行う例を示したが、圧力スイングに温度スイングをも組み合わせて行ってもよい。   In the above-described embodiment, an example in which the adsorption / regeneration switching operation of the CO adsorbent is performed only by raising or lowering the atmospheric pressure (that is, pressure swing) is shown. However, the pressure swing may be combined with the temperature swing. .

また、上記実施形態では、ＣＯ吸着剤の再生に用いるＣＯを実質的に含まないガスとして水素分離回収装置からのオフガスを例示したが、水素分離回収装置からの高純度水素、改質器の加熱用燃料、またはこれらのいずれか２種以上を混合して用いてもよい。   In the above embodiment, the off-gas from the hydrogen separation / recovery device is exemplified as the gas substantially free of CO used for the regeneration of the CO adsorbent. However, high purity hydrogen from the hydrogen separation / recovery device, heating of the reformer A fuel for use, or a mixture of any two or more of these may be used.

また、上記実施形態では、水素吸蔵材料からの水素放出を温度スイングで行う場合の熱源として燃料電池の冷却排水（約８０℃のお湯）を用いる例を示したが、変成ガスの顕熱、変成ガスに含まれる水蒸気の潜熱、改質器の燃焼排ガスの顕熱、またはこれらのいずれか２種以上を組み合わせて用いてもよい。   In the above embodiment, an example in which the cooling drainage (about 80 ° C. hot water) of the fuel cell is used as a heat source when releasing hydrogen from the hydrogen storage material by a temperature swing is shown. You may use combining the latent heat of the water vapor | steam contained in gas, the sensible heat of the combustion exhaust gas of a reformer, or any 2 or more types of these.

また、上記実施形態では、水素吸蔵材料の水素吸蔵／水素放出の切り替え操作を雰囲気圧力の昇降（圧力スイング）に加えて反応温度の昇降（すなわち、温度スイング）により行う例を示したが、圧力スイングのみで行うことも可能である。   In the above embodiment, an example in which the hydrogen storage / hydrogen release switching operation of the hydrogen storage material is performed by increasing / decreasing the reaction temperature (that is, temperature swing) in addition to increasing / decreasing the atmospheric pressure (pressure swing) is described. It is also possible to perform only by swinging.

また、上記実施形態では、ＣＯを含有する水素リッチガスの製造手段として改質器＋変成器の組合せを例示したが、変成器に代えてセラミックフィルタ等の粗製分離膜を用いてもよい。すなわち、上記実施形態では、ＣＯを含有する水素リッチガスとして炭化水素含有燃料を水蒸気で改質した後に変成したガス（変成ガス）を例示したが、水蒸気で改質した後にセラミックフィルタ等の粗製分離膜を流通させて水素濃度を高めたガスも当然に適用できる。   In the above embodiment, the combination of the reformer and the transformer is exemplified as the means for producing the hydrogen-rich gas containing CO. However, a crude separation membrane such as a ceramic filter may be used instead of the transformer. That is, in the above embodiment, the gas (modified gas) modified after reforming the hydrocarbon-containing fuel with steam as the hydrogen-rich gas containing CO is exemplified, but the crude separation membrane such as a ceramic filter after reforming with steam Naturally, a gas in which hydrogen concentration is increased by circulating the gas can also be applied.

さらには、ＣＯ吸着剤のＣＯ吸着性能や水素吸蔵材料の耐ＣＯ被毒性によっては、変成器を省略して改質器のみのプロセスも成立しうる。すなわち、ＣＯを含有する水素リッチガスとして、水蒸気で改質したままのガスも適用可能であり、さらには水蒸気改質に代えて部分酸化により改質したガス、あるいは部分酸化により改質させると同時に水蒸気で改質したガスも適用しうるものである。   Furthermore, depending on the CO adsorption performance of the CO adsorbent and the CO poisoning resistance of the hydrogen storage material, a process using only the reformer can be realized by omitting the transformer. That is, as the hydrogen-rich gas containing CO, a gas that has been reformed with steam can also be applied. Further, instead of steam reforming, gas reformed by partial oxidation, or steam reformed simultaneously with partial oxidation. The gas modified with the above can also be applied.

また、ＣＯ吸着剤を再生する際に放出されるＣＯは、改質ガスとともに変成器に導入して変成反応に利用することもできる。   Further, CO released when the CO adsorbent is regenerated can be introduced into a shifter together with the reformed gas and used for the shift reaction.

２…ＣＯ除去器
２ａ，２ｂ…ＣＯ吸着塔
３…水素分離回収装置
３ａ，３ｂ，３ｃ…水素吸蔵材料容器
７…真空ポンプ
８…バッファタンク
Ｂ…変成ガス（ＣＯを含有する水素リッチガス）
Ｃ…ＣＯ除去ガス
Ｄ…高純度水素
Ｅ…オフガス
Ｆ…ＣＯ非含有ガス（ＣＯを実質的に含まないガス） DESCRIPTION OF SYMBOLS 2 ... CO remover 2a, 2b ... CO adsorption tower 3 ... Hydrogen separation collection | recovery apparatus 3a, 3b, 3c ... Hydrogen storage material container 7 ... Vacuum pump 8 ... Buffer tank B ... Metamorphic gas (hydrogen rich gas containing CO)
C ... CO removal gas D ... High purity hydrogen E ... Off gas F ... CO-free gas (gas substantially free of CO)

Claims (3)

ＣＯ吸着剤を充填してなるＣＯ吸着塔を１または複数有するＣＯ除去器と、その後段に、水素吸蔵材料を充填した水素吸蔵材料容器を１または複数有する水素分離回収装置を備えた高純度水素製造装置を用いて、ＣＯを含有する水素リッチガス（以下、「ＣＯ含有水素リッチガス」という。）から高純度水素を製造する方法であって、
前記ＣＯ含有水素リッチガスを前記ＣＯ除去器でＣＯを除去してＣＯ除去ガスを得るＣＯ吸着除去工程と、前記ＣＯ除去ガスに含まれる水素を前記水素吸蔵材料に吸蔵させた後、この吸蔵された水素を前記吸蔵材料から放出させることにより高純度水素を得る水素分離回収工程とを備え、
前記水素分離回収工程は、各水素吸蔵材料容器について、少なくとも、前記ＣＯ除去ガスに含まれる水素を前記水素吸蔵材料に吸蔵させる水素吸蔵ステップと、この吸蔵された水素を前記吸蔵材料から放出させる水素放出ステップとを含むものであり、
前記ＣＯ吸着除去工程は、各ＣＯ吸着塔について、前記ＣＯ含有水素リッチガスを流通させてＣＯを吸着除去しＣＯ除去ガスを得るＣＯ吸着ステップと、ＣＯを実質的に含まないガス（以下、「ＣＯ非含有ガス」という。）を導入して当該ＣＯ吸着塔内に滞留したＣＯ除去ガスを排気して前記水素放出ステップ以外のステップにある水素吸蔵材料容器内に放出する雰囲気置換ステップと、前記ＣＯ非含有ガスを流通させつつＣＯ吸着剤を再生するＣＯ吸着剤再生ステップと、をその順序で繰り返すものである、
ことを特徴とする高純度水素製造方法。 High purity hydrogen equipped with a CO remover having one or more CO adsorption towers filled with a CO adsorbent, and a hydrogen separation and recovery device having one or more hydrogen storage material containers filled with a hydrogen storage material in the subsequent stage A method for producing high-purity hydrogen from a hydrogen-rich gas containing CO (hereinafter referred to as “CO-containing hydrogen-rich gas”) using a production apparatus,
A CO adsorption / removal step of removing CO from the CO-containing hydrogen rich gas with the CO remover to obtain a CO removal gas, and the hydrogen occlusion material that occludes hydrogen contained in the CO removal gas, and then occluded. A hydrogen separation and recovery step of obtaining high-purity hydrogen by releasing hydrogen from the storage material,
The hydrogen separation and recovery step includes, for each hydrogen storage material container, at least a hydrogen storage step for storing hydrogen contained in the CO removal gas in the hydrogen storage material, and hydrogen for releasing the stored hydrogen from the storage material. A release step,
The CO adsorption and removal step includes, for each CO adsorption tower, a CO adsorption step in which the CO-containing hydrogen rich gas is circulated to adsorb and remove CO to obtain a CO removal gas, and a gas that does not substantially contain CO (hereinafter referred to as “CO”). Non-containing gas ”)), an atmosphere replacement step in which the CO removal gas staying in the CO adsorption tower is exhausted and released into the hydrogen storage material container in a step other than the hydrogen release step, and the CO A CO adsorbent regeneration step for regenerating the CO adsorbent while circulating the non-containing gas, and repeating in that order.
A high-purity hydrogen production method characterized by the above. 前記雰囲気置換ステップにおいて、前記ＣＯ非含有ガスとして、前記水素吸蔵材料容器から排出される、前記水素吸蔵ステップで吸蔵されなかったオフガスを用いるに際し、前記ＣＯ吸着塔内の雰囲気圧力を該オフガスの圧力より低下させてから該オフガスを当該ＣＯ吸着塔内に流通させる請求項１に記載の高純度水素製造方法。   In the atmosphere replacement step, when using the off gas discharged from the hydrogen storage material container and not stored in the hydrogen storage step as the CO-free gas, the atmospheric pressure in the CO adsorption tower is changed to the pressure of the off gas. The high-purity hydrogen production method according to claim 1, wherein the off-gas is circulated in the CO adsorption tower after being further reduced. 前記ＣＯ吸着剤が、シリカ、アルミナ、活性炭、グラファイトおよびポリスチレン系樹脂よりなる群から選択される１種以上の担体に、ハロゲン化銅（Ｉ）および／またはハロゲン化銅（II）を担持させた材料であることを特徴とする請求項１または２に記載の高純度水素製造方法。   The CO adsorbent has copper (I) halide and / or copper (II) halide supported on one or more carriers selected from the group consisting of silica, alumina, activated carbon, graphite and polystyrene resin. The method for producing high-purity hydrogen according to claim 1 or 2, wherein the method is a material.
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