JP2015163393A - Method and equipment for oxygen separation - Google Patents

Method and equipment for oxygen separation Download PDF

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JP2015163393A
JP2015163393A JP2015014459A JP2015014459A JP2015163393A JP 2015163393 A JP2015163393 A JP 2015163393A JP 2015014459 A JP2015014459 A JP 2015014459A JP 2015014459 A JP2015014459 A JP 2015014459A JP 2015163393 A JP2015163393 A JP 2015163393A
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たかし 原岡
Takashi Haraoka
たかし 原岡
齋間　等
Hitoshi Saima
等 齋間
智也 藤峰
Tomoya Fujimine
智也 藤峰
真哉 大井
Masaya Oi
真哉 大井
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JFE Steel Corp
Tokyo Gas Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To acquire highly-concentrated oxygen by performing absorption and separation using a PSA method to efficiently separate oxygen from air without performing a purge process.SOLUTION: A method to acquire highly-concentrated oxygen comprises two stages including: a first stage of introducing air into an absorption tower filled with absorbent absorbing oxygen to perform PSA; and a second stage of introducing highly-concentrated oxygen gas desorbed from the absorption tower of the first stage into an absorption tower filled with absorbent absorbing nitrogen to perform the PSA, to efficiently separate oxygen from air without performing a purge process in the PSA.

Description

本発明は、圧力スイング吸着法を利用して、空気から酸素を分離するための酸素分離方法及び設備に関する。   The present invention relates to an oxygen separation method and equipment for separating oxygen from air using a pressure swing adsorption method.

酸素は製鉄業において重要な素材であり、国内の酸素需要の約３割を占める。鉄鉱石から粗鋼を製造する際には１トン当たり１２０Ｎｍ３程度の酸素が使用されており、また、昨今のさらなる省エネルギーの必要性から、空気ではなく酸素或いは酸素富化空気を利用した燃焼を指向する傾向が高まっている。このため、酸素の製造コストの低減は産業界における重要課題の一つとも言える。 Oxygen is an important material in the steel industry and accounts for about 30% of domestic oxygen demand. In manufacturing a crude steel from iron ore have been used oxygen of about 1 ton 120 Nm 3, also the need for further energy saving in recent years, oriented combustion using oxygen or oxygen-enriched air rather than air The tendency to do is increasing. For this reason, it can be said that reduction of the manufacturing cost of oxygen is one of the important issues in the industry.

酸素は空気を原料としたガス分離法によって製造されるのが一般的であり、製鉄所のように大量に酸素を必要とする場合には、酸素の製造に深冷分離法が用いられている。酸素製造の原単位としては、現状では深冷分離法が有利であるが、この方法は、空気を液化して酸素と窒素の沸点差を利用して酸素を分離することから設備規模が大きくなりやすい。このため、原単位では劣るものの、設備がコンパクト化し易い圧力スイング吸着法（ＰＳＡ法）や膜分離法も利用されている。   Oxygen is generally produced by a gas separation method using air as a raw material. When a large amount of oxygen is required as in a steel mill, a cryogenic separation method is used for producing oxygen. . At present, the cryogenic separation method is advantageous as a basic unit for oxygen production. However, this method increases the scale of equipment because air is liquefied and oxygen is separated using the difference between the boiling points of oxygen and nitrogen. Cheap. For this reason, although the basic unit is inferior, the pressure swing adsorption method (PSA method) and the membrane separation method which are easy to make equipment compact are also used.

酸素製造（分離）原単位の削減のために、これまでも多くの試みがなされてきており、特にＰＳＡ法に使用する吸着材や膜材料の提案がなされてきた。吸着材では、リチウムを置換又は担持したゼオライトが窒素に対する吸着性が高いことから、空気から窒素を分離して酸素を得るＰＳＡ装置に実用化されている。また、膜材料では、ポリエチレンテレフタル酸樹脂膜を化学的修飾して酸素透過性を高めた機能性高分子膜が開発され、実用化されている。   Many attempts have been made so far to reduce the oxygen production (separation) unit, and in particular, an adsorbent and a membrane material used for the PSA method have been proposed. As an adsorbent, zeolite substituted or supported with lithium has high adsorbability with respect to nitrogen, and thus has been put to practical use in a PSA apparatus that separates nitrogen from air to obtain oxygen. As a membrane material, a functional polymer membrane in which oxygen permeability is improved by chemically modifying a polyethylene terephthalic acid resin membrane has been developed and put into practical use.

また、最近では、ペロブスカイトと呼ばれる無機化合物を吸着材や膜材料として使用する提案がなされている。ペロブスカイトとは一種類の化合物名ではなく、特徴的な結晶構造を有する様々な化合物の総称であり、一般的な表現はＡＢＯｘである。通常、ＡおよびＢの元素に限定はないが、特に酸素の分離に使用されるものは、Ａは第２族、第３族およびランタノイドに属する元素（Ｓｒ、Ｂａ、Ｙ、Ｌａなど）であり、Ｂは第７族から第９族に属する元素（Ｍｎ、Ｆｅ、Ｃｏなど）であり、それぞれ１種類の元素であっても、複数種類の元素であってもよい。ペロブスカイトは、温度あるいは酸素分圧の変化により結晶構造が変化し、構造中のＯの数（ｘ）が変わることで酸素を吸収、放出するのが特徴である。この性質を利用したガス分離方法として、圧力スイング吸着法や温度スイング吸着法が提案されている。 Recently, proposals have been made to use an inorganic compound called perovskite as an adsorbent or film material. Perovskite is not a single type of compound name, but a general term for various compounds having a characteristic crystal structure, and a general expression is ABO x . Usually, there is no limitation on the elements of A and B, but especially those used for the separation of oxygen are elements belonging to Group 2, Group 3 and lanthanoids (Sr, Ba, Y, La, etc.) , B are elements belonging to Group 7 to Group 9 (Mn, Fe, Co, etc.), and each may be one kind of element or plural kinds of elements. Perovskites are characterized in that the crystal structure changes with changes in temperature or oxygen partial pressure, and oxygen is absorbed and released by changing the number (x) of O in the structure. As a gas separation method using this property, a pressure swing adsorption method and a temperature swing adsorption method have been proposed.

特開２００５−０９７９４１号公報JP 2005-079441 A 特開２００８−０１２４３９号公報JP 2008-012439 A 特開２０１０−０１２３６７号公報JP 2010-012367 A

従来の圧力スイング吸着法では、ガス分離工程として、空気を導入して吸着材に酸素を吸着させる「吸着工程」と、吸着材から真空ポンプ等の排気手段を使って酸素を脱着させる「脱着工程」が最低限必要であるが、一般に吸着工程と脱着工程のみでは分離されるガスの酸素濃度を９５vol％以上とすることは難しい。酸素濃度をさらに高めるには、吸着塔内の酸素濃度を高めるための「パージ」と呼ばれる工程が必要となり、このため設備の構造（配管や切り替えのための弁など）が複雑になるという問題がある。   In the conventional pressure swing adsorption method, as the gas separation process, an “adsorption process” in which air is introduced and oxygen is adsorbed on the adsorbent, and an oxygen desorption process using an exhaust means such as a vacuum pump from the adsorbent is performed. "Is a minimum requirement, but it is generally difficult to make the oxygen concentration of the separated gas 95 vol% or more only by the adsorption step and the desorption step. In order to further increase the oxygen concentration, a process called “purge” is required to increase the oxygen concentration in the adsorption tower, which causes the problem that the equipment structure (piping, valves for switching, etc.) is complicated. is there.

したがって本発明の目的は、ＰＳＡ法を用いた吸着分離においてパージ工程を行うことなく、空気から酸素を効率的に分離し、高濃度の酸素を得ることができる酸素分離方法及び設備を提供することにある。   Therefore, an object of the present invention is to provide an oxygen separation method and equipment capable of efficiently separating oxygen from air and obtaining a high concentration of oxygen without performing a purge step in adsorption separation using the PSA method. It is in.

本発明者らは、上記のような従来技術の課題を解決すべく検討を重ねた結果、空気からの酸素の分離を二段階で行うこと、具体的には、一段目では酸素の吸着材が充填された吸着塔に空気を導入してＰＳＡを行い、二段目では、一段目の吸着塔から脱着された酸素濃縮ガスを、窒素の吸着材が充填された吸着塔に導入してＰＳＡを行うことより、ＰＳＡにおいてパージ工程を行うことなく、空気から酸素を効率的に分離し、高濃度の酸素ガスが得られることを見出した。   As a result of repeated studies to solve the above-described problems of the prior art, the present inventors have performed the separation of oxygen from air in two stages. Specifically, in the first stage, an oxygen adsorbent is present. PSA is performed by introducing air into the packed adsorption tower. In the second stage, the oxygen-enriched gas desorbed from the first stage adsorption tower is introduced into the adsorption tower filled with a nitrogen adsorbent, and PSA is introduced. As a result, it has been found that oxygen can be efficiently separated from the air and a high-concentration oxygen gas can be obtained without performing a purge step in the PSA.

本発明はこのような知見に基づきなされたもので、以下を要旨とするものである。
［1］圧力スイング吸着方式による吸着塔であって、酸素を主として吸着する吸着材が充填された吸着塔（１）に空気を導入し、ガス吸着を行う工程（Ａ）と、
工程（Ａ）で吸着塔（１）に吸着されたガス（ｇ１）を脱着する工程（Ｂ）と、
工程（Ｂ）で脱着されたガス（ｇ１）を、圧力スイング吸着方式による吸着塔であって、窒素を主として吸着する吸着材が充填された吸着塔（２）に導入し、ガス吸着を行う工程（Ｃ）と、
工程（Ｃ）で吸着塔（２）に吸着されることなく排気されたガス（ｇ２）を高酸素濃度ガスとして回収する工程（Ｄ）を有することを特徴とする酸素分離方法。 The present invention has been made on the basis of such findings and has the following gist.
[1] An adsorption tower using a pressure swing adsorption method, wherein air is introduced into an adsorption tower (1) filled with an adsorbent mainly adsorbing oxygen to perform gas adsorption;
A step (B) of desorbing the gas (g 1 ) adsorbed on the adsorption tower (1) in the step (A);
The gas (g 1 ) desorbed in the step (B) is introduced into an adsorption tower (2) which is a pressure swing adsorption system and is filled with an adsorbent that mainly adsorbs nitrogen, and performs gas adsorption. Step (C),
An oxygen separation method comprising a step (D) of recovering a gas (g 2 ) exhausted without being adsorbed by the adsorption tower (2) in the step (C) as a high oxygen concentration gas.

［2］上記［1］の酸素分離方法において、工程（Ａ）のために吸着塔（１）に導入される前の空気と、工程（Ａ）で吸着塔（１）に吸着されることなく排気されたガス（ｇ３）を熱交換し、ガス（ｇ３）の顕熱で前記空気を昇温させることを特徴とする酸素分離方法。
［3］上記［1］又は［2］の酸素分離方法において、工程（Ｃ）で吸着塔（２）に吸着された後、脱着されたガス（ｇ４）を、工程（Ａ）のために吸着塔（１）に導入される前の空気に混合することを特徴とする酸素分離方法。
［4］上記［1］〜［3］のいずれかの酸素分離方法において、２基の吸着塔（１）で工程（Ａ）と工程（Ｂ）を交互に行う酸素分離方法であって、一方の吸着塔（１）の工程（Ｂ）で脱着されたガス（ｇ１）と、工程（Ａ）のために他方の吸着塔（１）に導入される前の空気を熱交換し、ガス（ｇ１）の顕熱で前記空気を昇温させることを特徴とする酸素分離方法。 [2] In the oxygen separation method of [1] above, the air before being introduced into the adsorption tower (1) for the step (A), and without being adsorbed by the adsorption tower (1) in the step (A) An oxygen separation method, wherein the exhausted gas (g 3 ) is subjected to heat exchange, and the temperature of the air is increased by sensible heat of the gas (g 3 ).
[3] In the oxygen separation method of the above-mentioned [1] or [2], after being adsorbed to the adsorption tower (2) in step (C), desorbed gas (g 4), for step (A) An oxygen separation method comprising mixing with air before being introduced into the adsorption tower (1).
[4] The oxygen separation method according to any one of [1] to [3], wherein the step (A) and the step (B) are alternately performed in two adsorption towers (1), The gas (g 1 ) desorbed in the step (B) of the adsorption tower (1) and the air before being introduced into the other adsorption tower (1) for the step (A) are subjected to heat exchange, and the gas ( An oxygen separation method, wherein the air is heated with sensible heat of g 1 ).

［5］酸素を主として吸着する吸着材が充填された吸着塔（１）を備えた圧力スイング吸着装置（１０）と、
吸着塔（１）に空気を供給する送風手段（４）と、
吸着塔（１）に吸着されたガス（ｇ１）を脱着時に排気する排気手段（５）と、
窒素を主として吸着する吸着材が充填され、排気手段（５）により吸着塔（１）から排気されたガス（ｇ１）が供給される吸着塔（２）を備えた圧力スイング吸着装置（２０）を備え、
吸着塔（２）に吸着されることなく排気されたガス（ｇ２）が高酸素濃度ガスとして回収されるようにしたことを特徴とする酸素分離設備。 [5] a pressure swing adsorption device (10) including an adsorption tower (1) filled with an adsorbent mainly adsorbing oxygen;
A blowing means (4) for supplying air to the adsorption tower (1);
An exhaust means (5) for exhausting the gas (g 1 ) adsorbed on the adsorption tower (1) at the time of desorption;
Pressure swing adsorption device (20) provided with an adsorption tower (2) filled with an adsorbent mainly adsorbing nitrogen and supplied with gas (g 1 ) exhausted from the adsorption tower (1) by the exhaust means (5) With
An oxygen separation facility characterized in that the gas (g 2 ) exhausted without being adsorbed by the adsorption tower (2) is recovered as a high oxygen concentration gas.

［6］上記［5］の酸素分離設備において、さらに、吸着塔（１）に導入される前の空気と、吸着塔（１）に吸着されることなく排気されたガス（ｇ３）を熱交換する熱交換器（２４）を備えることを特徴とする酸素分離設備。
［7］上記［5］又は［6］の酸素分離設備において、吸着塔（２）に吸着された後、脱着されたガス（ｇ４）の排気管（１７）を、送風手段（４）が設けられた空気供給管（８）であって、送風手段（４）の上流側の管部位置に接続したことを特徴とする酸素分離設備。
［8］上記［5］〜［7］のいずれかの酸素設備において、吸着工程と脱着工程を交互に行う２基の吸着塔（１）を備えた酸素分離設備であって、さらに、一方の吸着塔（１）から脱着されたガス（ｇ１）と、他方の吸着塔（１）に導入される前の空気を熱交換する熱交換器（２５）を備えることを特徴とする酸素分離設備。 [6] In the oxygen separation facility of [5] above, the air before being introduced into the adsorption tower (1) and the gas (g 3 ) exhausted without being adsorbed by the adsorption tower (1) are further heated. An oxygen separation facility comprising a heat exchanger (24) for replacement.
[7] In the oxygen separation facility of [5] or [6] above, the air blowing means (4) passes the exhaust pipe (17) of the gas (g 4 ) desorbed after being adsorbed by the adsorption tower (2). An oxygen separation facility comprising an air supply pipe (8) provided and connected to a pipe position upstream of the blower means (4).
[8] In the oxygen equipment according to any one of [5] to [7], the oxygen separation equipment includes two adsorption towers (1) for alternately performing the adsorption process and the desorption process, An oxygen separation facility comprising a heat exchanger (25) for exchanging heat between the gas (g 1 ) desorbed from the adsorption tower (1) and the air before being introduced into the other adsorption tower (1). .

［9］上記［8］の酸素設備において、圧力スイング吸着装置（１０）は、２基の吸着塔（１ａ），（１ｂ）と、これら吸着塔（１ａ），（１ｂ）で吸着工程と脱着工程を交互に行うためにガスを給排気することができる配管系を備え、該配管系に送風手段（４）と排気手段（５）が設けられ、
圧力スイング吸着装置（２０）は、２基の吸着塔（２ａ），（２ｂ）と、これら吸着塔（２ａ），（２ｂ）で吸着工程と脱着工程を交互に行うためにガスを給排気することができる配管系を備えることを特徴とする酸素分離設備。 [9] In the oxygen equipment of [8] above, the pressure swing adsorption device (10) is composed of two adsorption towers (1a) and (1b) and an adsorption process and desorption in these adsorption towers (1a) and (1b). A piping system capable of supplying and exhausting gas for alternately performing the steps is provided, and the ventilation system (4) and the exhausting means (5) are provided in the piping system,
The pressure swing adsorption device (20) supplies and exhausts gas in order to alternately perform an adsorption process and a desorption process in the two adsorption towers (2a) and (2b) and these adsorption towers (2a) and (2b). An oxygen separation facility comprising a piping system capable of performing the above.

本発明によれば、空気からの酸素の分離を二段階で行い、一段目では酸素を主として吸着する吸着材が充填された吸着塔に空気を導入してＰＳＡを行い、二段目では、一段目の吸着塔から脱着された酸素濃縮ガスを、窒素を主として吸着する吸着材が充填された吸着塔に導入してＰＳＡを行うことより、ＰＳＡおいてパージ工程を行うことなく、空気から酸素を効率的に分離し、高濃度の酸素ガスを得ることができる。
また、ＰＳＡにより酸素を吸着する一段目の吸着塔に導入する前の空気を、当該吸着塔から排気された高温の脱着ガスや非吸着ガスとの熱交換で昇温させる方法の場合には、ＰＳＡにより酸素を吸着する吸着塔から排気されるガスによる熱ロスを小さくすることができる。
さらに、二段目の吸着塔から脱着されたガスを原料の空気に混合し、原料の一部として用いる方法の場合には、酸素の回収率をより高めることができる。 According to the present invention, separation of oxygen from air is performed in two stages. In the first stage, air is introduced into an adsorption tower packed with an adsorbent mainly adsorbing oxygen, and PSA is performed. In the second stage, one stage is performed. By introducing the oxygen-enriched gas desorbed from the eye adsorption tower into an adsorption tower filled with an adsorbent that mainly adsorbs nitrogen, and performing PSA, oxygen is removed from the air without performing a purge step in PSA. It can be separated efficiently and a high concentration oxygen gas can be obtained.
In the case of a method of heating the air before being introduced into the first stage adsorption tower that adsorbs oxygen by PSA by heat exchange with the high-temperature desorption gas or non-adsorption gas exhausted from the adsorption tower, The heat loss due to the gas exhausted from the adsorption tower that adsorbs oxygen by PSA can be reduced.
Furthermore, in the case of a method in which the gas desorbed from the second stage adsorption tower is mixed with the raw material air and used as a part of the raw material, the oxygen recovery rate can be further increased.

本発明の酸素分離設備の一実施形態を示す構成図The block diagram which shows one Embodiment of the oxygen separation equipment of this invention 本発明の酸素分離方法の一実施形態（図１の酸素分離設備を用いた実施形態）において、吸着塔１ａと吸着塔２ａが吸着工程、吸着塔１ｂと吸着塔２ｂが脱着工程にあるときの開閉弁の開閉状態及びガス流れを示す説明図In one embodiment of the oxygen separation method of the present invention (embodiment using the oxygen separation facility of FIG. 1), the adsorption tower 1a and the adsorption tower 2a are in the adsorption step, and the adsorption tower 1b and the adsorption tower 2b are in the desorption step. Explanatory drawing which shows the open / close state of the on-off valve and the gas flow 本発明の酸素分離方法の一実施形態（図１の酸素分離設備を用いた実施形態）において、吸着塔１ａと吸着塔２ａが脱着工程、吸着塔１ｂと吸着塔２ｂが吸着工程にあるときの開閉弁の開閉状態及びガス流れを示す説明図In one embodiment of the oxygen separation method of the present invention (embodiment using the oxygen separation facility of FIG. 1), the adsorption tower 1a and the adsorption tower 2a are in the desorption process, and the adsorption tower 1b and the adsorption tower 2b are in the adsorption process. Explanatory drawing which shows the open / close state of the on-off valve and the gas flow 本発明の酸素分離設備の他の実施形態を示す構成図The block diagram which shows other embodiment of the oxygen separation equipment of this invention 本発明の酸素分離方法の他の実施形態（図４の酸素分離設備を用いた実施形態）において、吸着塔１ａと吸着塔２ａが吸着工程、吸着塔１ｂと吸着塔２ｂが脱着工程にあるときの開閉弁の開閉状態及びガス流れを示す説明図In another embodiment of the oxygen separation method of the present invention (embodiment using the oxygen separation facility of FIG. 4), when the adsorption tower 1a and the adsorption tower 2a are in the adsorption step, and the adsorption tower 1b and the adsorption tower 2b are in the desorption step Explanatory drawing which shows the open / close state of the on-off valve and the gas flow 本発明の酸素分離方法の他の実施形態（図４の酸素分離設備を用いた実施形態）において、吸着塔１ａと吸着塔２ａが脱着工程、吸着塔１ｂと吸着塔２ｂが吸着工程にあるときの開閉弁の開閉状態及びガス流れを示す説明図In another embodiment of the oxygen separation method of the present invention (embodiment using the oxygen separation facility of FIG. 4), when the adsorption tower 1a and the adsorption tower 2a are in the desorption process, and the adsorption tower 1b and the adsorption tower 2b are in the adsorption process Explanatory drawing which shows the open / close state of the on-off valve and the gas flow

本発明の酸素分離方法は、空気から酸素を分離するための方法であり、圧力スイング吸着方式による吸着塔であって、酸素を主として吸着する吸着材が充填された吸着塔１に空気を導入し、ガス吸着を行う工程Ａと、この工程Ａで吸着塔１に吸着されたガスｇ１を脱着する工程Ｂと、この工程Ｂで脱着されたガスｇ１を、圧力スイング吸着方式による吸着塔であって、窒素を主として吸着する吸着材が充填された吸着塔２に導入し、ガス吸着を行う工程Ｃと、この工程Ｃで吸着塔２に吸着されることなく排気されたガスｇ２を高酸素濃度ガスとして回収する工程Ｄを有する。この酸素分離方法は、一段目の工程Ａと二段目の工程Ｃでガス分離を行うことにより高酸素濃度ガスを得るものであり、このため、工程Ａ（吸着工程）と工程Ｂ（脱着工程）間でパージ工程は行わない。 The oxygen separation method of the present invention is a method for separating oxygen from air, and is an adsorption tower using a pressure swing adsorption method, in which air is introduced into an adsorption tower 1 filled with an adsorbent mainly adsorbing oxygen. a step a of performing gas adsorption, a step B of desorbing gas g 1 adsorbed to the adsorption tower 1 in this step a, the gas g 1 desorbed by this process B, the adsorption tower by the pressure swing adsorption method Then, a process C for introducing gas into the adsorption tower 2 filled with an adsorbent mainly adsorbing nitrogen and performing gas adsorption, and a gas g 2 exhausted without being adsorbed by the adsorption tower 2 in this process C It has the process D collect | recovered as oxygen concentration gas. In this oxygen separation method, high oxygen concentration gas is obtained by performing gas separation in the first step A and the second step C. Therefore, the step A (adsorption step) and the step B (desorption step) are performed. ) Is not performed in between.

また、この酸素分離方法の実施に供する酸素分離設備は、酸素を主として吸着する吸着材が充填された吸着塔１を備えた圧力スイング吸着装置１０と、吸着塔１に空気を供給する送風手段４と、吸着塔１に吸着されたガスｇ１を脱着時に排気する排気手段５と、窒素を主として吸着する吸着材が充填され、排気手段５により吸着塔１から排気されたガスｇ１が供給される吸着塔２を備えた圧力スイング吸着装置２０を備え、吸着塔２に吸着されることなく排気されたガスｇ２が高酸素濃度ガスとして回収されるようにしたものである。この酸素分離設備のガス分離手段は、一段目の圧力スイング吸着装置１０と二段目の圧力スイング吸着装置２０からなるが、上記のように吸着工程と脱着工程間でパージ工程は行わないため、この酸素分離設備は、パージ工程を行うための設備構成は備えない。 The oxygen separation equipment used for carrying out this oxygen separation method includes a pressure swing adsorption device 10 having an adsorption tower 1 filled with an adsorbent that mainly adsorbs oxygen, and a blowing means 4 for supplying air to the adsorption tower 1. And an exhaust means 5 for exhausting the gas g 1 adsorbed to the adsorption tower 1 at the time of desorption, and an adsorbent that mainly adsorbs nitrogen, and the gas g 1 exhausted from the adsorption tower 1 by the exhaust means 5 is supplied. a pressure swing adsorption apparatus 20 having a adsorption tower 2 that is obtained by such a gas g 2 exhausted without being adsorbed to the adsorption column 2 is recovered as high oxygen concentration gas. The gas separation means of this oxygen separation equipment consists of the first-stage pressure swing adsorption device 10 and the second-stage pressure swing adsorption device 20, but no purge process is performed between the adsorption process and the desorption process as described above. This oxygen separation facility does not have a facility configuration for performing the purge process.

図１は、本発明の酸素分離設備の一実施形態を示すものである。
本実施形態では、圧力スイング吸着装置１０（以下、「ＰＳＡ装置１０」という）が２基の吸着塔１ａ，１ｂを備え、また、圧力スイング吸着装置２０（以下、「ＰＳＡ装置２０」という）も２基の吸着塔２ａ，２ｂを備えている。
ＰＳＡ装置１０が備える２基の吸着塔１ａ，１ｂは、それぞれ吸着塔を５００〜６００℃程度まで加熱するための加熱手段７を備えている。この加熱手段７は、吸着塔を外囲するように設置される電熱ヒーター等で構成される。 FIG. 1 shows one embodiment of the oxygen separation facility of the present invention.
In this embodiment, the pressure swing adsorption apparatus 10 (hereinafter referred to as “PSA apparatus 10”) includes two adsorption towers 1a and 1b, and the pressure swing adsorption apparatus 20 (hereinafter referred to as “PSA apparatus 20”) also. Two adsorption towers 2a and 2b are provided.
The two adsorption towers 1a and 1b provided in the PSA apparatus 10 are each provided with heating means 7 for heating the adsorption tower to about 500 to 600 ° C. The heating means 7 is composed of an electric heater or the like installed so as to surround the adsorption tower.

吸着塔１ａ，１ｂに充填される酸素を主として吸着する吸着材とは、空気を通したときに酸素の吸着容量が窒素の吸着容量に較べて大きい吸着材である。この吸着材は、酸素を主として吸着できるものであれば、その種類に特別な制限はないが、吸着性能の面からはペロブスカイト型吸着材が望ましい。先に述べたように、ペロブスカイトの構造の一般的な表現はＡＢＯｘである。このＡおよびＢの元素に限定はないが、特に本発明のように酸素の分離に使用するものは、Ａは第２族、第３族およびランタノイドに属する元素（Ｓｒ、Ｂａ、Ｙ、Ｌａなど）であり、Ｂは第７族から第９族に属する元素（Ｍｎ、Ｆｅ、Ｃｏなど）であり、それぞれ、それらの中から選ばれる１種類の元素であっても、複数種類の元素であってもよい。ペロブスカイトは、温度あるいは酸素分圧の変化により結晶構造が変化し、構造中のＯの数（ｘ）が変わることで酸素を吸収、放出する。ペロブスカイト型吸着材としては、例えば、ＳｒＦｅＯｘ、ＢａＦｅＯｘ、ＳｒＮｉＯｘ、ＳｒＣｏＯｘや、特開２００５−８７９４１号公報、特開２００８−１２４３９号公報に示されるものなどを挙げることができるが、これらに限定されるものではない。 The adsorbent mainly adsorbing oxygen filled in the adsorption towers 1a and 1b is an adsorbent having a larger oxygen adsorption capacity than that of nitrogen when air is passed. The adsorbent is not particularly limited as long as it can mainly adsorb oxygen, but a perovskite adsorbent is desirable from the standpoint of adsorption performance. As mentioned earlier, a general representation of the structure of perovskite is ABO x . The elements of A and B are not limited, but in particular, those used for oxygen separation as in the present invention, A is an element belonging to Group 2, Group 3, and lanthanoid (Sr, Ba, Y, La, etc. B is an element belonging to Group 7 to Group 9 (Mn, Fe, Co, etc.), and each of them may be a single element selected from the group consisting of a plurality of types of elements. May be. Perovskite changes its crystal structure with changes in temperature or oxygen partial pressure, and absorbs and releases oxygen by changing the number (x) of O in the structure. Examples of the perovskite-type adsorbent include SrFeO x , BaFeO x , SrNiO x , SrCoO x, and those disclosed in JP-A-2005-87941 and JP-A-2008-12439. It is not limited to.

また、吸着塔２ａ，２ｂに充填される窒素を主として吸着する吸着材とは、空気を通したときに窒素の吸着容量が酸素の吸着容量に較べて大きい吸着材である。この吸着材は、窒素を主として吸着できるものであれば、その種類に特別な制限はないが、吸着性能の面からは、リチウムを置換又は担持したゼオライト（Ｌｉ置換又は担持ゼオライト）が特に好ましい。   The adsorbent mainly adsorbing nitrogen filled in the adsorption towers 2a and 2b is an adsorbent having a larger nitrogen adsorption capacity than oxygen adsorption capacity when air is passed. The adsorbent is not particularly limited as long as it can mainly adsorb nitrogen, but from the standpoint of adsorption performance, a lithium-substituted or supported zeolite (Li-substituted or supported zeolite) is particularly preferable.

送風手段４はブロア等で構成され、吸着塔１ａ，１ｂに酸素を供給する酸素供給管８に設けられている。この酸素供給管８の下流側は、吸着塔１ａ，１ｂに対応して２本の分岐供給管８０ａ，８０ｂに分岐している。また、排気手段５は真空ポンプ等で構成され、吸着塔１ａ，１ｂの吸着ガスを排気するガス排気管９に設けられている。このガス排気管９の上流側は、吸着塔１ａ，１ｂに対応して２本の分岐排気管９０ａ，９０ｂに分岐している。
そして、分岐供給管８０ａと分岐排気管９０ａが合流してガス給排管１１ａとなり、このガス給排管１１ａが吸着塔１ａの一端（下部側）に接続されている。また、分岐供給管８０ｂと分岐排気管９０ｂが合流してガス給排管１１ｂとなり、このガス給排管１１ｂが吸着塔１ｂの一端（下部側）に接続されている。 The air blowing means 4 is composed of a blower or the like, and is provided in an oxygen supply pipe 8 that supplies oxygen to the adsorption towers 1a and 1b. The downstream side of the oxygen supply pipe 8 is branched into two branch supply pipes 80a and 80b corresponding to the adsorption towers 1a and 1b. The exhaust means 5 is composed of a vacuum pump or the like, and is provided in a gas exhaust pipe 9 that exhausts the adsorbed gas of the adsorption towers 1a and 1b. The upstream side of the gas exhaust pipe 9 is branched into two branch exhaust pipes 90a and 90b corresponding to the adsorption towers 1a and 1b.
The branch supply pipe 80a and the branch exhaust pipe 90a merge to form a gas supply / discharge pipe 11a, and this gas supply / discharge pipe 11a is connected to one end (lower side) of the adsorption tower 1a. Further, the branch supply pipe 80b and the branch exhaust pipe 90b merge to form a gas supply / discharge pipe 11b, and this gas supply / discharge pipe 11b is connected to one end (lower side) of the adsorption tower 1b.

吸着塔１ａ，１ｂを通過した非吸着ガス（オフガス）を排出するためのガス排気管１２は、その上流側が吸着塔１ａ，１ｂに対応して２本の分岐排気管１２０ａ，１２０ｂに分岐し、これら分岐排気管１２０ａ，１２０ｂが、吸着塔１ａ，１ｂの他端（上部側）に接続されている。
分岐供給管８０ａ，８０ｂ、分岐排気管９０ａ，９０ｂ、分岐排出管１２０ａ，１２０ｂには、それぞれ開閉弁１３ａ，１３ｂ，１４ａ，１４ｂ，１５ａ，１５ｂ（自動開閉弁）が設けられ、吸脱着の各工程に応じて開閉されるようになっている。また、ガス排気管１２には背圧弁１６が設けられ、吸着塔内を所定圧力に維持しつつ非吸着ガスを排出できるようにしている。 The gas exhaust pipe 12 for discharging the non-adsorbed gas (off-gas) that has passed through the adsorption towers 1a and 1b has its upstream side branched into two branch exhaust pipes 120a and 120b corresponding to the adsorption towers 1a and 1b, These branch exhaust pipes 120a and 120b are connected to the other end (upper side) of the adsorption towers 1a and 1b.
The branch supply pipes 80a and 80b, the branch exhaust pipes 90a and 90b, and the branch discharge pipes 120a and 120b are provided with on-off valves 13a, 13b, 14a, 14b, 15a, and 15b (automatic on-off valves), respectively. It is opened and closed according to the process. Further, a back pressure valve 16 is provided in the gas exhaust pipe 12 so that the non-adsorbed gas can be discharged while maintaining the inside of the adsorption tower at a predetermined pressure.

ガス排気管９の下流側は、吸着塔２ａ，２ｂへのガス供給管を構成しており、吸着塔２ａ，２ｂに対応して２本の分岐供給管９１ａ，９１ｂに分岐している。一方、吸着塔２ａ，２ｂの吸着ガスを排気するガス排気管１７には、真空ポンプ等の排気手段６が設けられている。このガス排気管１７の上流側は、吸着塔２ａ，２ｂに対応して２本の分岐排気管１７０ａ，１７０ｂに分岐している。そして、分岐供給管９１ａと分岐排気管１７０ａが合流してガス給排管１８ａとなり、このガス給排管１８ａが吸着塔２ａの一端（下部側）に接続されている。また、分岐供給管９１ｂと分岐排気管１７０ｂが合流してガス給排管１８ｂとなり、このガス給排管１８ｂが吸着塔２ｂの一端（下部側）に接続されている。   The downstream side of the gas exhaust pipe 9 constitutes a gas supply pipe to the adsorption towers 2a and 2b, and branches into two branch supply pipes 91a and 91b corresponding to the adsorption towers 2a and 2b. On the other hand, the gas exhaust pipe 17 for exhausting the adsorbed gas of the adsorption towers 2a and 2b is provided with an exhaust means 6 such as a vacuum pump. The upstream side of the gas exhaust pipe 17 is branched into two branch exhaust pipes 170a and 170b corresponding to the adsorption towers 2a and 2b. The branch supply pipe 91a and the branch exhaust pipe 170a merge to form a gas supply / discharge pipe 18a, and this gas supply / discharge pipe 18a is connected to one end (lower side) of the adsorption tower 2a. Further, the branch supply pipe 91b and the branch exhaust pipe 170b merge to form a gas supply / discharge pipe 18b, and this gas supply / discharge pipe 18b is connected to one end (lower side) of the adsorption tower 2b.

吸着塔２ａ，２ｂを通過した非吸着ガス（オフガス）を排出するためのガス排気管１９は、その上流側が吸着塔２ａ，２ｂに対応して２本の分岐排気管１９０ａ，１９０ｂに分岐し、これら分岐排気管１９０ａ，１９０ｂが、吸着塔２ａ，２ｂの他端（上部側）に接続されている。
分岐供給管９１ａ，９１ｂ、分岐排気管１７０ａ，１７０ｂ、分岐排出管１９０ａ，１９０ｂには、それぞれ開閉弁２１ａ，２１ｂ，２２ａ，２２ｂ，２３ａ，２３ｂ（自動開閉弁）が設けられ、吸脱着の各工程に応じて開閉されるようになっている。
本発明の酸素分離設備の操業では、後述するように、各吸着塔１ａ，１ｂにおいて、吸着工程と脱着工程間でパージ工程は行わないため、パージ工程を行うための設備構成は備えない。 The gas exhaust pipe 19 for discharging the non-adsorbed gas (off-gas) that has passed through the adsorption towers 2a and 2b has its upstream side branched into two branch exhaust pipes 190a and 190b corresponding to the adsorption towers 2a and 2b, These branch exhaust pipes 190a and 190b are connected to the other end (upper side) of the adsorption towers 2a and 2b.
The branch supply pipes 91a and 91b, the branch exhaust pipes 170a and 170b, and the branch discharge pipes 190a and 190b are provided with open / close valves 21a, 21b, 22a, 22b, 23a, and 23b (automatic open / close valves), respectively. It is opened and closed according to the process.
In the operation of the oxygen separation facility according to the present invention, as will be described later, in each of the adsorption towers 1a and 1b, the purge step is not performed between the adsorption step and the desorption step, and therefore no equipment configuration for performing the purge step is provided.

以下、図１の酸素分離設備を用いた本発明の酸素分離方法の一実施形態について、図２及び図３に基づいて説明する。図２は、吸着塔１ａと吸着塔２ａが吸着工程、吸着塔１ｂと吸着塔２ｂが脱着工程にあるときの開閉弁の開閉状態及びガス流れを示す説明図、図３は、吸着塔１ａと吸着塔２ａが脱着工程、吸着塔１ｂと吸着塔２ｂが吸着工程にあるときの開閉弁の開閉状態及びガス流れを示す説明図である。図２及び図３において、太線がガスの流れている流路を示し、開閉弁のなかで黒塗りが閉状態のもの、白抜きが開状態のものである。
なお、吸着塔１ａ，１ｂは、必要に応じて、加熱手段７により吸着材の酸素吸着・脱着に必要な温度まで加熱される。 Hereinafter, an embodiment of the oxygen separation method of the present invention using the oxygen separation facility of FIG. 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is an explanatory view showing the open / close state of the on-off valve and the gas flow when the adsorption tower 1a and the adsorption tower 2a are in the adsorption process, and the adsorption tower 1b and the adsorption tower 2b are in the desorption process, and FIG. It is explanatory drawing which shows the opening-and-closing state and gas flow of an on-off valve when the adsorption tower 2a exists in a desorption process and the adsorption tower 1b and the adsorption tower 2b are in an adsorption process. 2 and 3, the thick line indicates the flow path through which the gas flows. Among the on-off valves, the black paint is in the closed state and the white is in the open state.
In addition, the adsorption towers 1a and 1b are heated to a temperature necessary for oxygen adsorption / desorption of the adsorbent by the heating means 7 as necessary.

図２において、原料である空気ｇ０は、送風手段４によって空気供給管８、分岐供給管８０ａ、ガス給排気管１１ａを通じて吸着塔１ａに導入され、塔内に充填された吸着材（酸素を主として吸着する吸着材）に酸素が主として吸着される（工程Ａ）。吸着塔１ａ内で酸素濃度が低下したガスは、非吸着ガスとして塔上部から排気され、分岐排出管１２０ａ、ガス排出管１２を通じて背圧弁１６を介して排気（ガスｇ３）される。一方、上記のように吸着塔１ａでガス吸着が行われる工程Ａの間、前回行われた工程Ａで吸着塔１ｂ内の吸着材に吸着されているガスｇ１（酸素濃度が高いガス）が、排気手段５によって吸着塔１ｂから脱着され（工程Ｂ）、ガス給排管１１ｂ、分岐排気管９０ｂ、ガス排気管９を通じて排気される。以上が一段目のＰＳＡによるガス分離工程であり、このＰＳＡでは吸着工程と脱着工程間でのパージ工程は行われない。 In FIG. 2, air g 0 as a raw material is introduced into the adsorption tower 1a through the air supply pipe 8, the branch supply pipe 80a, and the gas supply / exhaust pipe 11a by the blowing means 4, and the adsorbent (oxygen is charged) filled in the tower. Oxygen is mainly adsorbed on the adsorbent that is mainly adsorbed (step A). The gas having a reduced oxygen concentration in the adsorption tower 1a is exhausted from the top of the tower as a non-adsorbed gas, and exhausted through the branch discharge pipe 120a and the gas discharge pipe 12 through the back pressure valve 16 (gas g 3 ). On the other hand, during the process A in which gas adsorption is performed in the adsorption tower 1a as described above, the gas g 1 (gas having a high oxygen concentration) adsorbed on the adsorbent in the adsorption tower 1b in the process A performed last time. Then, it is desorbed from the adsorption tower 1b by the exhaust means 5 (step B) and exhausted through the gas supply / exhaust pipe 11b, the branch exhaust pipe 90b, and the gas exhaust pipe 9. The above is the gas separation process by the first stage PSA, and the purge process between the adsorption process and the desorption process is not performed in this PSA.

吸着塔１ｂから脱着され、ガス排気管９を通じて排気された上記ガスｇ１は、二段目のＰＳＡによるガス分離工程に送られる。すなわち、ガスｇ１は、ガス排気管９に連なる分岐供給管９１ａ、ガス給排管１８ａを通じて吸着塔２ａに導入され、塔内に充填された吸着材（窒素を主として吸着する吸着材）に窒素が主として吸着される（工程Ｃ）。吸着塔２ａに吸着されることなく排気されたガスｇ２（非吸着ガス）は、窒素分が吸着塔２ａで吸着除去されて酸素濃度がさらに高くなっており、分岐排気管１９０ａ、ガス排気管１９を通じて排気され、製品ガスである高酸素濃度ガスとして回収される（工程Ｄ）。一方、上記のように吸着塔２ａでガス吸着が行われる工程Ｃの間、前回行われた工程Ｃで窒素が主として吸着された吸着塔２ｂから排気手段６により窒素が多いガスが脱着され、排気される（ガスｇ４）。 Desorbed from the adsorption tower 1b, the gas g 1 which is exhausted through the gas exhaust pipe 9 is fed to the gas separation process by PSA of the second stage. That is, the gas g 1, the branch supply pipes 91a communicating with the gas exhaust pipe 9 is introduced into the adsorption tower 2a through the gas supply and discharge line 18a, the nitrogen to the adsorbent filled in column (adsorbent mainly adsorbing nitrogen) Is mainly adsorbed (step C). The gas g 2 (non-adsorbed gas) exhausted without being adsorbed by the adsorption tower 2a has a nitrogen content adsorbed and removed by the adsorption tower 2a, resulting in a higher oxygen concentration. The branch exhaust pipe 190a and the gas exhaust pipe It is exhausted through 19 and recovered as a high oxygen concentration gas that is a product gas (step D). On the other hand, during the process C in which gas adsorption is performed in the adsorption tower 2a as described above, a gas rich in nitrogen is desorbed by the exhaust means 6 from the adsorption tower 2b in which nitrogen is mainly adsorbed in the previous process C, and exhausted. (Gas g 4 ).

この酸素分離方法では、一段目ＰＳＡの吸着工程と脱着工程間でのパージ工程が行われないが、二段目ＰＳＡにおいて、一段目ＰＳＡで脱着されたガスｇ１（酸素濃縮ガス）の窒素分が吸着除去されるので、二段目ＰＳＡで吸着されることなく排気されたガスｇ２（非吸着ガス）は酸素濃度がさらに高められ、これを高酸素濃度ガスとして回収することができる。 In this oxygen separation method, the purge step between the adsorption step and the desorption step of the first-stage PSA is not performed, but the nitrogen content of the gas g 1 (oxygen-enriched gas) desorbed in the first-stage PSA in the second-stage PSA. Is absorbed and removed, the gas g 2 (non-adsorbed gas) exhausted without being adsorbed by the second-stage PSA is further increased in oxygen concentration, and can be recovered as a high oxygen concentration gas.

図２の状態で吸着塔１ａ，１ｂと吸着塔２ａ，２ｂによる上記工程が完了した時点で、開閉弁の開閉状態を図３に示すように変更して吸着塔１ａ，１ｂと吸着塔２ａ，２ｂの切り替えを行い、以下のようなガス分離を行う。
図３において、原料である空気ｇ０は、送風手段４によって空気供給管８、分岐供給管８０ｂ、ガス給排気管１１ｂを通じて吸着塔１ｂに導入され、塔内に充填された吸着材（酸素を主として吸着する吸着材）に酸素が主として吸着される（工程Ａ）。吸着塔１ｂ内で酸素濃度が低下したガスは、非吸着ガスとして塔上部から排気され、分岐排出管１２０ｂ、ガス排出管１２を通じて背圧弁１６を介して排気（ガスｇ３）される。一方、上記のように吸着塔１ｂでガス吸着が行われる工程Ａの間、前回行われた工程Ａで吸着塔１ａ内の吸着材に吸着されているガスｇ１（酸素濃度が高いガス）が、排気手段５によって吸着塔１ａから脱着され（工程Ｂ）、ガス給排管１１ａ、分岐排気管９０ａ、ガス排気管９を通じて排気される。以上が一段目のＰＳＡによるガス分離工程であり、この一段目ＰＳＡでは吸着工程と脱着工程間でのパージ工程は行われない。 When the above steps by the adsorption towers 1a and 1b and the adsorption towers 2a and 2b are completed in the state of FIG. 2, the open / close state of the on-off valve is changed as shown in FIG. 3 to change the adsorption towers 1a and 1b and the adsorption tower 2a, 2b is switched and the following gas separation is performed.
In FIG. 3, air g 0 as a raw material is introduced into the adsorption tower 1b through the air supply pipe 8, the branch supply pipe 80b, and the gas supply / exhaust pipe 11b by the blowing means 4, and the adsorbent (oxygen is charged) filled in the tower. Oxygen is mainly adsorbed on the adsorbent that is mainly adsorbed (step A). The gas having a reduced oxygen concentration in the adsorption tower 1b is exhausted from the top of the tower as a non-adsorbed gas, and exhausted through the branch discharge pipe 120b and the gas discharge pipe 12 through the back pressure valve 16 (gas g 3 ). On the other hand, during the process A in which gas adsorption is performed in the adsorption tower 1b as described above, the gas g 1 (gas having a high oxygen concentration) adsorbed on the adsorbent in the adsorption tower 1a in the process A performed last time. Then, it is desorbed from the adsorption tower 1a by the exhaust means 5 (step B) and exhausted through the gas supply / exhaust pipe 11a, the branch exhaust pipe 90a, and the gas exhaust pipe 9. The above is the gas separation process by the first stage PSA, and the purge process between the adsorption process and the desorption process is not performed in the first stage PSA.

吸着塔１ａから脱着され、ガス排気管９を通じて排気された上記ガスｇ１は、二段目のＰＳＡによるガス分離工程に送られる。すなわち、ガスｇ１は、ガス排気管９に連なる分岐供給管９１ｂ、ガス給排管１８ｂを通じて吸着塔２ｂに導入され、塔内に充填された吸着材（窒素を主として吸着する吸着材）に窒素が主として吸着される（工程Ｃ）。吸着塔２ｂに吸着されることなく排気されたガスｇ２（非吸着ガス）は、窒素分が吸着塔２ｂで吸着除去されて酸素濃度がさらに高くなっており、分岐排気管１９０ｂ、ガス排気管１９を通じて排気され、製品ガスである高酸素濃度ガスとして回収される（工程Ｄ）。一方、上記のように吸着塔２ｂでガス吸着が行われる工程Ｃの間、前回行われた工程Ｃで窒素が主として吸着された吸着塔２ａから排気手段６により窒素が多いガスが脱着され、排気される（ガスｇ４）。
以上の図２、図３の工程を繰り返し行うことで、原料である空気ｇ０から高酸素濃度ガス（ガスｇ２）を連続的に得ることができる。 The gas g 1 desorbed from the adsorption tower 1a and exhausted through the gas exhaust pipe 9 is sent to the gas separation step by the second stage PSA. That is, the gas g 1, the branch supply pipes 91b communicating with the gas exhaust pipe 9 is introduced into the adsorption tower 2b through the gas supply and discharge line 18b, the nitrogen to the adsorbent filled in column (adsorbent mainly adsorbing nitrogen) Is mainly adsorbed (step C). The gas g 2 (non-adsorbed gas) exhausted without being adsorbed by the adsorption tower 2b has a nitrogen content adsorbed and removed by the adsorption tower 2b to further increase the oxygen concentration. The branch exhaust pipe 190b and the gas exhaust pipe It is exhausted through 19 and recovered as a high oxygen concentration gas that is a product gas (step D). On the other hand, during the process C in which gas adsorption is performed in the adsorption tower 2b as described above, a gas containing a large amount of nitrogen is desorbed by the exhaust means 6 from the adsorption tower 2a in which nitrogen is mainly adsorbed in the previous process C. (Gas g 4 ).
By repeatedly performing the steps of FIGS. 2 and 3 described above, a high oxygen concentration gas (gas g 2 ) can be continuously obtained from the air g 0 as a raw material.

本発明は、一段目のＰＳＡ装置（吸着塔１）で空気から酸素を吸着し、この一段目のＰＳＡ装置（吸着塔１）から脱着されたガスを二段目のＰＳＡ装置（吸着塔２）に導入して窒素を吸着し、このＰＳＡ装置（吸着塔２）の非吸着ガス（オフガス）を高酸素濃度ガスとして回収するものであるが、上述した実施形態のように、直列に接続された２段のＰＳＡ装置（吸着塔１，２）でガスの吸着・脱着を行うだけでは、得られる酸素回収率には一定の限界がある。
また、さきに述べたように、吸着塔１に充填される吸着材（酸素を主として吸着する吸着材）としては、吸着性能の面からペロブスカイト型吸着材が好ましいが、この吸着材は５００〜６００℃といった高温状態で使用される（酸素の吸着・脱着）ものであり、このため吸着材の熱が吸着塔１から排出されるガスに着熱して熱ロスとなる問題がある。 In the present invention, oxygen is adsorbed from air by the first-stage PSA apparatus (adsorption tower 1), and the gas desorbed from the first-stage PSA apparatus (adsorption tower 1) is converted into the second-stage PSA apparatus (adsorption tower 2). Is introduced to adsorb nitrogen, and the non-adsorbed gas (off-gas) of this PSA device (adsorption tower 2) is recovered as a high oxygen concentration gas, but connected in series as in the above-described embodiment. There is a certain limit to the oxygen recovery rate obtained only by gas adsorption / desorption with a two-stage PSA apparatus (adsorption towers 1 and 2).
As described above, the adsorbent (adsorbent that mainly adsorbs oxygen) packed in the adsorption tower 1 is preferably a perovskite type adsorbent from the standpoint of adsorption performance. It is used in a high temperature state such as ° C. (oxygen adsorption / desorption). For this reason, there is a problem that the heat of the adsorbent reaches the gas discharged from the adsorption tower 1 to cause heat loss.

本発明の酸素分離方法は、上記のような課題を解決するために、以下のような好ましい形態を採ることができる。
（i） 工程Ａのために吸着塔１に導入される前の空気と、工程Ａで吸着塔１に吸着されることなく排気されたガスｇ３を熱交換し、ガスｇ３の顕熱で前記空気を昇温させる。
（ii） 工程Ｃで吸着塔２に吸着された後、脱着されたガスｇ４を、工程Ａのために吸着塔１に導入される前の空気に混合する。
（iii） ２基の吸着塔１で工程Ａと工程Ｂを交互に行う酸素分離方法であって、一方の吸着塔１の工程Ｂで脱着されたガスｇ１と、工程Ａのために他方の吸着塔１に導入される前の空気を熱交換し、ガスｇ１の顕熱で前記空気を昇温させる。 The oxygen separation method of the present invention can take the following preferable forms in order to solve the above-described problems.
(I) Heat exchange between the air before being introduced into the adsorption tower 1 for the process A and the gas g 3 exhausted without being adsorbed by the adsorption tower 1 in the process A, and the sensible heat of the gas g 3 The air is heated.
(Ii) The gas g 4 desorbed after being adsorbed on the adsorption tower 2 in the step C is mixed with the air before being introduced into the adsorption tower 1 for the step A.
(Iii) An oxygen separation method in which Step A and Step B are alternately performed in two adsorption towers 1, wherein the gas g 1 desorbed in Step B of one adsorption tower 1 and the other for the step A air prior to introduction into the adsorption column 1 and heat exchanger, raising the temperature of the air in the sensible heat of the gas g 1.

上記（i）、（iii）により吸着塔１から排出されるガスへの着熱による熱ロスを少なくすることができるが、特に上記（i）と（iii）を組み合わせ、吸着塔１に導入する前の空気を吸着塔１から排気された高温のガスｇ１（脱着ガス）とガスｇ３（非吸着ガス）との２段階の熱交換により昇温させることにより、吸着塔１から排出されるガスへの着熱による熱ロスをより効果的に低減させることができる。また、上記（ii）により酸素回収率を高めることができる。このため上記（i）〜（iii）を組み合わせることにより、酸素回収率を高めることができるとともに、吸着塔１から排出されるガスへの着熱による熱ロスを最も効果的に低減させることができる。 Although the heat loss due to heat applied to the gas discharged from the adsorption tower 1 can be reduced by the above (i) and (iii), the above (i) and (iii) are combined and introduced into the adsorption tower 1 in particular. The previous air is discharged from the adsorption tower 1 by raising the temperature by two-stage heat exchange between the high-temperature gas g 1 (desorption gas) and the gas g 3 (non-adsorption gas) exhausted from the adsorption tower 1. It is possible to more effectively reduce the heat loss due to the heat applied to the gas. Further, the oxygen recovery rate can be increased by the above (ii). For this reason, by combining the above (i) to (iii), it is possible to increase the oxygen recovery rate and to most effectively reduce the heat loss due to the heat applied to the gas discharged from the adsorption tower 1. .

また、この酸素分離方法の実施に供する酸素分離設備は、上記課題を解決するために、以下のような好ましい形態を採ることができる。
（1） さらに、吸着塔１に導入される前の空気と、吸着塔１に吸着されることなく排気されたガスｇ３を熱交換する熱交換器２４を備える。
（2） 吸着塔２に吸着された後、脱着されたガスｇ４の排気管１７を、送風手段４が設けられた空気供給管８であって、送風手段４の上流側の管部位置に接続する。
（3） 吸着工程と脱着工程を交互に行う２基の吸着塔１を備えた酸素分離設備であって、さらに、一方の吸着塔１から脱着されたガスｇ１と、他方の吸着塔１に導入される前の空気を熱交換する熱交換器２５を備える。 Moreover, in order to solve the said subject, the oxygen separation equipment used for implementation of this oxygen separation method can take the following preferable forms.
(1) further comprises an air prior to being introduced into the adsorption tower 1, a heat exchanger 24 for heat exchange gas g 3 exhausted without being adsorbed in the adsorption tower 1.
(2) The exhaust pipe 17 of the gas g 4 desorbed after being adsorbed by the adsorption tower 2 is an air supply pipe 8 provided with the blowing means 4, and is positioned at the upstream pipe position of the blowing means 4. Connecting.
(3) An oxygen separation facility having two adsorption towers 1 that alternately perform an adsorption process and a desorption process, and further includes gas g 1 desorbed from one adsorption tower 1 and the other adsorption tower 1 A heat exchanger 25 is provided for exchanging heat before air is introduced.

図４は、本発明の酸素分離設備の他の実施形態を示すものであり、上述した好ましい形態（1）〜（3）を備えた酸素分離設備である。
この酸素分離設備の基本構成は、図１の実施形態と同様であるので、同一の符号を付し、詳細な説明は省略する。
この酸素分離設備は、図１の基本構成に加えて、熱交換器２４ａ，２４ｂ、熱交換器２５ａ，２５ｂを備えている。 FIG. 4 shows another embodiment of the oxygen separation facility of the present invention, which is an oxygen separation facility equipped with the preferred embodiments (1) to (3) described above.
Since the basic configuration of this oxygen separation facility is the same as that of the embodiment of FIG. 1, the same reference numerals are given, and detailed description thereof is omitted.
This oxygen separation facility includes heat exchangers 24a and 24b and heat exchangers 25a and 25b in addition to the basic configuration shown in FIG.

熱交換器２４ａ，２４ｂは、吸着塔１ａ，１ｂに導入される前の空気ｇ０と、吸着塔１ａ，１ｂに吸着されることなく排気されたガスｇ３（オフガス）を熱交換するものである。
したがって、熱交換器２４ａは、吸着塔１ａを通過した非吸着ガス（オフガス）を排出するための分岐排気管１２０ａと、吸着塔１ａに空気を供給する分岐供給管８０ａに対して設けられる。すなわち、熱交換器２４ａの一次側流路（流路の入口・出口）に分岐排気管１２０ａが接続され、二次側流路（流路の入口・出口）に分岐供給管８０ａが接続される。また、熱交換器２４ｂは、吸着塔１ｂを通過した非吸着ガス（オフガス）を排出するための分岐排気管１２０ｂと、吸着塔１ｂに空気を供給する分岐供給管８０ｂに対して設けられる。すなわち、熱交換器２４ｂの一次側流路（流路の入口・出口）に分岐排気管１２０ｂが接続され、二次側流路（流路の入口・出口）に分岐供給管８０ｂが接続される。 Heat exchangers 24a, 24b is the adsorption tower 1a, the air g 0 before being introduced into 1b, the adsorption tower 1a, the gas g 3 exhausted without being adsorbed to 1b (the off gas) intended to heat exchange is there.
Therefore, the heat exchanger 24a is provided for the branch exhaust pipe 120a for discharging the non-adsorbed gas (off-gas) that has passed through the adsorption tower 1a and the branch supply pipe 80a for supplying air to the adsorption tower 1a. That is, the branch exhaust pipe 120a is connected to the primary flow path (flow path inlet / outlet) of the heat exchanger 24a, and the branch supply pipe 80a is connected to the secondary flow path (flow path inlet / outlet). . The heat exchanger 24b is provided for the branch exhaust pipe 120b for discharging the non-adsorbed gas (off-gas) that has passed through the adsorption tower 1b, and the branch supply pipe 80b for supplying air to the adsorption tower 1b. That is, the branch exhaust pipe 120b is connected to the primary flow path (flow path inlet / outlet) of the heat exchanger 24b, and the branch supply pipe 80b is connected to the secondary flow path (flow path inlet / outlet). .

熱交換器２５ａ，２５ｂは、２基の吸着塔１ａ，１ｂのうち、一方の吸着塔１に導入される前の空気ｇ０と、他方の吸着塔１から脱着されたガスｇ１を熱交換するものである。
したがって、熱交換器２５ａは、吸着塔１ｂの吸着ガスを排気（脱着）する分岐排気管９０ｂと、吸着塔１ａに空気を供給する分岐供給管８０ａに対して設けられる。すなわち、熱交換器２５ａの一次側流路（流路の入口・出口）に分岐排気管９０ｂが接続され、二次側流路（流路の入口・出口）に分岐供給管８０ａが接続される。また、熱交換器２５ｂは、吸着塔１ａの吸着ガスを排気（脱着）する分岐排気管９０ａと、吸着塔１ｂに空気を供給する分岐供給管８０ｂに対して設けられる。すなわち、熱交換器２５ｂの一次側流路（流路の入口・出口）に分岐排気管９０ａが接続され、二次側流路（流路の入口・出口）に分岐供給管８０ｂが接続される。 The heat exchangers 25 a and 25 b exchange heat between the air g 0 before being introduced into one of the two adsorption towers 1 a and 1 b and the gas g 1 desorbed from the other adsorption tower 1. To do.
Therefore, the heat exchanger 25a is provided with respect to the branch exhaust pipe 90b which exhausts (desorbs) the adsorption gas of the adsorption tower 1b, and the branch supply pipe 80a which supplies air to the adsorption tower 1a. That is, the branch exhaust pipe 90b is connected to the primary flow path (flow path inlet / outlet) of the heat exchanger 25a, and the branch supply pipe 80a is connected to the secondary flow path (flow path inlet / outlet). . Moreover, the heat exchanger 25b is provided with respect to the branch exhaust pipe 90a which exhausts (desorbs) the adsorption gas of the adsorption tower 1a, and the branch supply pipe 80b which supplies air to the adsorption tower 1b. That is, the branch exhaust pipe 90a is connected to the primary flow path (flow path inlet / outlet) of the heat exchanger 25b, and the branch supply pipe 80b is connected to the secondary flow path (flow path inlet / outlet). .

分岐供給管８０ａ，８０ｂにおいては、空気ｇ０の流れ方向で開閉弁１３ａ，１３ｂの下流側に熱交換器２５ａ，２５ｂ、熱交換器２４ａ，２４ｂの順で配置されている。これは、熱交換器２５ａ，２５ｂの一次側のガスｇ１と、熱交換器２４ａ，２４ｂの一次側のガスｇ３は、通常、ガス量がｇ３＞ｇ１であるため、ガス量の少ないガスｇ１を先に空気ｇ０の温度が低い状態で熱交換させ、次いで、ガス量の多いガスｇ３と若干温度の上昇した空気ｇ０と熱交換する方が、空気ｇ０を効率的に昇温させることができるからである。
また、吸着塔２ａ，２ｂから脱着されるガスｇ４のガス排気管１７は、送風手段４の上流側の空気供給管８に接続され、ガスｇ４が空気ｇ０に混合されるようにしている。 Branch supply pipe 80a, in 80b, is disposed off valve 13a in the air flow direction g 0, on the downstream side of 13b the heat exchanger 25a, 25b, the heat exchanger 24a, in the order of 24b. This is because the gas g 1 on the primary side of the heat exchangers 25a and 25b and the gas g 3 on the primary side of the heat exchangers 24a and 24b usually have a gas amount of g 3 > g 1 . less gas g 1 above was heat exchange the temperature of the air g 0 is in a low state, then better to elevated air g 0 exchanges heat with slightly temperature and high gas g 3 of gas amount, the efficiency of air g 0 This is because the temperature can be increased.
The gas exhaust pipe 17 for the gas g 4 desorbed from the adsorption towers 2a and 2b is connected to the air supply pipe 8 on the upstream side of the blower means 4 so that the gas g 4 is mixed with the air g 0. Yes.

以下、図４の酸素分離設備を用いた本発明の酸素分離方法の一実施形態について、図５及び図６に基づいて説明する。図５は、吸着塔１ａと吸着塔２ａが吸着工程、吸着塔１ｂと吸着塔２ｂが脱着工程にあるときの開閉弁の開閉状態及びガス流れを示す説明図、図６は、吸着塔１ａと吸着塔２ａが脱着工程、吸着塔１ｂと吸着塔２ｂが吸着工程にあるときの開閉弁の開閉状態及びガス流れを示す説明図である。図５及び図６において、太線（実線、点線、破線）がガスの流れている流路を示し、開閉弁のなかで黒塗りが閉状態のもの、白抜きが開状態のものである。
この実施形態では、吸着塔１ａ，１ｂは加熱手段７で加熱され、塔内の吸着材は吸着工程・脱着工程とも高温状態（例えば、５００℃程度）で使用される。 Hereinafter, an embodiment of the oxygen separation method of the present invention using the oxygen separation facility of FIG. 4 will be described with reference to FIGS. 5 and 6. FIG. 5 is an explanatory view showing the open / close state of the on-off valve and the gas flow when the adsorption tower 1a and the adsorption tower 2a are in the adsorption process, and the adsorption tower 1b and the adsorption tower 2b are in the desorption process, and FIG. It is explanatory drawing which shows the opening-and-closing state and gas flow of an on-off valve when the adsorption tower 2a exists in a desorption process and the adsorption tower 1b and the adsorption tower 2b are in an adsorption process. 5 and 6, thick lines (solid line, dotted line, broken line) indicate flow paths through which gas flows, and among the on-off valves, the black paint is in the closed state and the white is in the open state.
In this embodiment, the adsorption towers 1a and 1b are heated by the heating means 7, and the adsorbent in the tower is used in a high temperature state (for example, about 500 ° C.) in both the adsorption process and the desorption process.

図５においても、図２の場合と同様に、原料である空気ｇ０は、送風手段４によって空気供給管８、分岐供給管８０ａ、ガス給排気管１１ａを通じて吸着塔１ａに導入され、塔内に充填された吸着材（酸素を主として吸着する吸着材）に酸素が主として吸着される（工程Ａ）。吸着塔１ａ内で酸素濃度が低下したガスは、非吸着ガスとして塔上部から排気され、分岐排出管１２０ａ、ガス排出管１２を通じて背圧弁１６を介して排気（ガスｇ３）される。一方、上記のように吸着塔１ａでガス吸着が行われる工程Ａの間、前回行われた工程Ａで吸着塔１ｂ内の吸着材に吸着されているガスｇ１（酸素濃度が高いガス）が、排気手段５によって吸着塔１ｂから脱着され（工程Ｂ）、ガス給排管１１ｂ、分岐排気管９０ｂ、ガス排気管９を通じて排気される。以上が一段目のＰＳＡによるガス分離工程であり、このＰＳＡでは吸着工程と脱着工程間でのパージ工程は行われない。 Also in FIG. 5, as in the case of FIG. 2, the air g 0 as the raw material is introduced into the adsorption tower 1a by the blowing means 4 through the air supply pipe 8, the branch supply pipe 80a, and the gas supply / exhaust pipe 11a. Oxygen is mainly adsorbed to the adsorbent filled in (adsorbent that mainly adsorbs oxygen) (step A). The gas having a reduced oxygen concentration in the adsorption tower 1a is exhausted from the top of the tower as a non-adsorbed gas, and exhausted through the branch discharge pipe 120a and the gas discharge pipe 12 through the back pressure valve 16 (gas g 3 ). On the other hand, during the process A in which gas adsorption is performed in the adsorption tower 1a as described above, the gas g 1 (gas having a high oxygen concentration) adsorbed on the adsorbent in the adsorption tower 1b in the process A performed last time. Then, it is desorbed from the adsorption tower 1b by the exhaust means 5 (step B) and exhausted through the gas supply / exhaust pipe 11b, the branch exhaust pipe 90b, and the gas exhaust pipe 9. The above is the gas separation process by the first stage PSA, and the purge process between the adsorption process and the desorption process is not performed in this PSA.

以上の一段目のＰＳＡによるガス分離工程において、吸着塔１ａに導入される空気ｇ０（常温）は、熱交換器２５ａにおいて、工程Ｂで吸着塔１ｂから脱着された上記ガスｇ１（例えば、約５００℃）と熱交換し、ガスｇ１の顕熱で昇温し、さらに熱交換器２４ａにおいて、吸着塔１ａに吸着されることなく排気された上記ガスｇ３（例えば、約５００℃）と熱交換し、ガスｇ３の顕熱でさらに昇温し、このように昇温した空気ｇ０が吸着塔１ａに導入される。 In the gas separation step by the first stage PSA, air g 0 (normal temperature) introduced into the adsorption tower 1a is the gas g 1 (for example, desorbed from the adsorption tower 1b in step B) in the heat exchanger 25a. about 500 ° C.) and heat exchange, the temperature was raised at a sensible heat of the gas g 1, in yet heat exchanger 24a, the gas g 3 exhausted without being adsorbed to the adsorption tower 1a (e.g., about 500 ° C.) a heat exchanger, the temperature was further raised in sensible heat of the gas g 3, air g 0 was heated in this manner is introduced into the adsorption tower 1a.

吸着塔１ｂから脱着され、上記熱交換器２５ａを経由した後、ガス排気管９を通じて排気された上記ガスｇ１は、二段目のＰＳＡによるガス分離工程に送られる。すなわち、図２の場合と同様に、ガスｇ１は、ガス排気管９に連なる分岐供給管９１ａ、ガス給排管１８ａを通じて吸着塔２ａに導入され、塔内に充填された吸着材（窒素を主として吸着する吸着材）に窒素が主として吸着される（工程Ｃ）。吸着塔２ａに吸着されることなく排気されたガスｇ２（非吸着ガス）は、窒素分が吸着塔２ａで吸着除去されて酸素濃度がさらに高くなっており、分岐排気管１９０ａ、ガス排気管１９を通じて排気され、製品ガスである高酸素濃度ガスとして回収される（工程Ｄ）。一方、上記のように吸着塔２ａでガス吸着が行われる工程Ｃの間、前回行われた工程Ｃで窒素が主として吸着された吸着塔２ｂから排気手段６により窒素が多いガスが脱着され、排気される（ガスｇ４）。このガスｇ４には相当量の酸素が含まれているため、ガス排出管１７を通じて送風手段４の上流側の空気供給管８内に導入し、空気ｇ０と混合して原料ガスの一部とする。 Desorbed from the adsorption tower 1b, after passing through the heat exchanger 25a, the gas g 1 which is exhausted through the gas exhaust pipe 9 is fed to the gas separation process by PSA of the second stage. That is, as in the case of FIG. 2, the gas g 1 is introduced into the adsorption tower 2a through the branch supply pipe 91a connected to the gas exhaust pipe 9 and the gas supply / discharge pipe 18a, and the adsorbent (nitrogen is charged) filled in the tower. Nitrogen is mainly adsorbed on the adsorbent that is mainly adsorbed (step C). The gas g 2 (non-adsorbed gas) exhausted without being adsorbed by the adsorption tower 2a has a nitrogen content adsorbed and removed by the adsorption tower 2a, resulting in a higher oxygen concentration. The branch exhaust pipe 190a and the gas exhaust pipe It is exhausted through 19 and recovered as a high oxygen concentration gas that is a product gas (step D). On the other hand, during the process C in which gas adsorption is performed in the adsorption tower 2a as described above, a gas rich in nitrogen is desorbed by the exhaust means 6 from the adsorption tower 2b in which nitrogen is mainly adsorbed in the previous process C, and exhausted. (Gas g 4 ). Since this gas g 4 contains a considerable amount of oxygen, it is introduced into the air supply pipe 8 on the upstream side of the blowing means 4 through the gas discharge pipe 17 and mixed with the air g 0 to part of the raw material gas. And

この酸素分離方法では、一段目ＰＳＡの吸着工程と脱着工程間でのパージ工程が行われないが、二段目ＰＳＡにおいて、一段目ＰＳＡで脱着されたガスｇ１（酸素濃縮ガス）の窒素分が吸着除去されるので、二段目ＰＳＡで吸着されることなく排気されたガスｇ２（非吸着ガス）は酸素濃度がさらに高められ、これを高酸素濃度ガスとして回収することができる。 In this oxygen separation method, the purge step between the adsorption step and the desorption step of the first-stage PSA is not performed, but the nitrogen content of the gas g 1 (oxygen-enriched gas) desorbed in the first-stage PSA in the second-stage PSA. Is absorbed and removed, the gas g 2 (non-adsorbed gas) exhausted without being adsorbed by the second-stage PSA is further increased in oxygen concentration, and can be recovered as a high oxygen concentration gas.

図５の状態で吸着塔１ａ，１ｂと吸着塔２ａ，２ｂによる上記工程が完了した時点で、開閉弁の開閉状態を図６に示すように変更して吸着塔１ａ，１ｂと吸着塔２ａ，２ｂの切り替えを行い、以下のようなガス分離を行う。
図６においても、図３の場合と同様に、原料である空気ｇ０は、送風手段４によって空気供給管８、分岐供給管８０ｂ、ガス給排気管１１ｂを通じて吸着塔１ｂに導入され、塔内に充填された吸着材（酸素を主として吸着する吸着材）に酸素が主として吸着される（工程Ａ）。吸着塔１ｂ内で酸素濃度が低下したガスは、非吸着ガスとして塔上部から排気され、分岐排出管１２０ｂ、ガス排出管１２を通じて背圧弁１６を介して排気（ガスｇ３）される。一方、上記のように吸着塔１ｂでガス吸着が行われる工程Ａの間、前回行われた工程Ａで吸着塔１ａ内の吸着材に吸着されているガスｇ１（酸素濃度が高いガス）が、排気手段５によって吸着塔１ａから脱着され（工程Ｂ）、ガス給排管１１ａ、分岐排気管９０ａ、ガス排気管９を通じて排気される。以上が一段目のＰＳＡによるガス分離工程であり、この一段目ＰＳＡでは吸着工程と脱着工程間でのパージ工程は行われない。 When the above steps by the adsorption towers 1a and 1b and the adsorption towers 2a and 2b are completed in the state of FIG. 5, the open / close state of the on-off valve is changed as shown in FIG. 6 to change the adsorption towers 1a and 1b and the adsorption tower 2a, 2b is switched and the following gas separation is performed.
In FIG. 6, as in the case of FIG. 3, the air g 0 as the raw material is introduced into the adsorption tower 1b by the blowing means 4 through the air supply pipe 8, the branch supply pipe 80b, and the gas supply / exhaust pipe 11b. Oxygen is mainly adsorbed to the adsorbent filled in (adsorbent that mainly adsorbs oxygen) (step A). The gas having a reduced oxygen concentration in the adsorption tower 1b is exhausted from the top of the tower as a non-adsorbed gas, and exhausted through the branch discharge pipe 120b and the gas discharge pipe 12 through the back pressure valve 16 (gas g 3 ). On the other hand, during the process A in which gas adsorption is performed in the adsorption tower 1b as described above, the gas g 1 (gas having a high oxygen concentration) adsorbed on the adsorbent in the adsorption tower 1a in the process A performed last time. Then, it is desorbed from the adsorption tower 1a by the exhaust means 5 (step B) and exhausted through the gas supply / exhaust pipe 11a, the branch exhaust pipe 90a, and the gas exhaust pipe 9. The above is the gas separation process by the first stage PSA, and the purge process between the adsorption process and the desorption process is not performed in the first stage PSA.

以上の一段目のＰＳＡによるガス分離工程において、吸着塔１ｂに導入される空気ｇ０（常温）は、熱交換器２５ｂにおいて、工程Ｂで吸着塔１ａから脱着された上記ガスｇ１（例えば、約５００℃）と熱交換し、ガスｇ１の顕熱で昇温し、さらに熱交換器２４ｂにおいて、吸着塔１ｂに吸着されることなく排気された上記ガスｇ３（例えば、約５００℃）と熱交換し、ガスｇ３の顕熱でさらに昇温し、このように昇温した空気ｇ０が吸着塔１ｂに導入される。 In the gas separation step by the first stage PSA described above, the air g 0 (normal temperature) introduced into the adsorption tower 1b is the gas g 1 (for example, desorbed from the adsorption tower 1a in step B) in the heat exchanger 25b. about 500 ° C.) and heat exchange, the temperature was raised at a sensible heat of the gas g 1, in yet heat exchanger 24b, the gas g 3 exhausted without being adsorbed to the adsorption tower 1b (e.g., about 500 ° C.) a heat exchanger, the temperature was further raised in sensible heat of the gas g 3, air g 0 was heated in this manner is introduced into the adsorption tower 1b.

吸着塔１ａから脱着され、上記熱交換器２５ｂを経由した後、ガス排気管９を通じて排気された上記ガスｇ１は、二段目のＰＳＡによるガス分離工程に送られる。すなわち、図３の場合と同様に、ガスｇ１は、ガス排気管９に連なる分岐供給管９１ｂ、ガス給排管１８ｂを通じて吸着塔２ｂに導入され、塔内に充填された吸着材（窒素を主として吸着する吸着材）に窒素が主として吸着される（工程Ｃ）。吸着塔２ｂに吸着されることなく排気されたガスｇ２（非吸着ガス）は、窒素分が吸着塔２ｂで吸着除去されて酸素濃度がさらに高くなっており、分岐排気管１９０ｂ、ガス排気管１９を通じて排気され、製品ガスである高酸素濃度ガスとして回収される（工程Ｄ）。一方、上記のように吸着塔２ｂでガス吸着が行われる工程Ｃの間、前回行われた工程Ｃで窒素が主として吸着された吸着塔２ａから排気手段６により窒素が多いガスが脱着され、排気される（ガスｇ４）。さきに述べたように、このガスｇ４には相当量の酸素が含まれているため、ガス排出管１７を通じて送風手段４の上流側の空気供給管８内に導入し、空気ｇ０と混合して原料ガスの一部とする。
以上の図５、図６の工程を繰り返し行うことで、原料である空気ｇ０から高酸素濃度ガス（ガスｇ２）を連続的に得ることができる。 The gas g 1 desorbed from the adsorption tower 1a, passed through the heat exchanger 25b, and then exhausted through the gas exhaust pipe 9 is sent to the gas separation step by the second stage PSA. That is, as in the case of FIG. 3, the gas g 1 is introduced into the adsorption tower 2b through the branch supply pipe 91b and the gas supply / discharge pipe 18b connected to the gas exhaust pipe 9, and the adsorbent (nitrogen is charged) filled in the tower. Nitrogen is mainly adsorbed on the adsorbent that is mainly adsorbed (step C). The gas g 2 (non-adsorbed gas) exhausted without being adsorbed by the adsorption tower 2b has a nitrogen content adsorbed and removed by the adsorption tower 2b to further increase the oxygen concentration. The branch exhaust pipe 190b and the gas exhaust pipe It is exhausted through 19 and recovered as a high oxygen concentration gas that is a product gas (step D). On the other hand, during the process C in which gas adsorption is performed in the adsorption tower 2b as described above, a gas containing a large amount of nitrogen is desorbed by the exhaust means 6 from the adsorption tower 2a in which nitrogen is mainly adsorbed in the previous process C. (Gas g 4 ). As described above, since this gas g 4 contains a considerable amount of oxygen, it is introduced into the air supply pipe 8 upstream of the blowing means 4 through the gas discharge pipe 17 and mixed with the air g 0. And make it part of the source gas.
By repeatedly performing the steps of FIGS. 5 and 6 described above, a high oxygen concentration gas (gas g 2 ) can be continuously obtained from the air g 0 as a raw material.

この酸素分離方法では、吸着塔１に導入される常温の空気ｇ０が、吸着塔１から排気された高温のガスｇ１（脱着ガス）とガスｇ３（非吸着ガス）との２段階の熱交換で昇温することにより、吸着塔１から排出されるガスへの着熱による熱ロスを効果的に低減させることができる。さらに、吸着塔２から脱着されたガスｇ４（脱着ガス）を原料の空気に混合し、原料ガスの一部として用いることにより、酸素の回収率を高めることができる。 In this oxygen separation method, room temperature air g 0 introduced into the adsorption tower 1 is divided into two stages of high-temperature gas g 1 (desorption gas) and gas g 3 (non-adsorption gas) exhausted from the adsorption tower 1. By raising the temperature by heat exchange, it is possible to effectively reduce the heat loss due to heat applied to the gas discharged from the adsorption tower 1. Furthermore, the gas g 4 (desorption gas) desorbed from the adsorption tower 2 is mixed with the raw material air and used as a part of the raw material gas, whereby the oxygen recovery rate can be increased.

１ａ，１ｂ 吸着塔
２ａ，２ｂ 吸着塔
４ 送風手段
５ 排気手段
６ 排気手段
７ 加熱手段
８ 空気供給管
９ ガス排気管
１０ 圧力スイング吸着装置
１１ａ，１１ｂ ガス給排管
１２ ガス排気管
１３ａ，１３ｂ，１４ａ，１４ｂ，１５ａ，１５ｂ 開閉弁
１６ 背圧弁
１７ ガス排気管
１８ａ，１８ｂ ガス給排管
１９ ガス排気管
２０ 圧力スイング吸着装置
２１ａ，２１ｂ，２２ａ，２２ｂ，２３ａ，２３ｂ 開閉弁
２４ａ，２４ｂ 熱交換器
２５ａ，２５ｂ 熱交換器
８０ａ，８０ｂ 分岐供給管
９０ａ，９０ｂ 分岐排気管
９１ａ，９１ｂ 分岐供給管
１２０ａ，１２０ｂ 分岐排気管
１７０ａ，１７０ｂ 分岐排気管
１９０ａ，１９０ｂ 分岐排気管
ｇ０ 空気
ｇ１，ｇ２，ｇ３，ｇ４ ガス 1a, 1b Adsorption tower 2a, 2b Adsorption tower 4 Blowing means 5 Exhaust means 6 Exhaust means 7 Heating means 8 Air supply pipe 9 Gas exhaust pipe 10 Pressure swing adsorption device 11a, 11b Gas supply / exhaust pipe 12 Gas exhaust pipe 13a, 13b, 14a, 14b, 15a, 15b On-off valve 16 Back pressure valve 17 Gas exhaust pipe 18a, 18b Gas supply / exhaust pipe 19 Gas exhaust pipe 20 Pressure swing adsorption device 21a, 21b, 22a, 22b, 23a, 23b On-off valve 24a, 24b Heat exchange 25a, 25b Heat exchangers 80a, 80b Branch supply pipes 90a, 90b Branch exhaust pipes 91a, 91b Branch supply pipes 120a, 120b Branch exhaust pipes 170a, 170b Branch exhaust pipes 190a, 190b Branch exhaust pipes g 0 air g 1 , g 2, g 3, g 4 gas

Claims (9)

圧力スイング吸着方式による吸着塔であって、酸素を主として吸着する吸着材が充填された吸着塔（１）に空気を導入し、ガス吸着を行う工程（Ａ）と、
工程（Ａ）で吸着塔（１）に吸着されたガス（ｇ１）を脱着する工程（Ｂ）と、
工程（Ｂ）で脱着されたガス（ｇ１）を、圧力スイング吸着方式による吸着塔であって、窒素を主として吸着する吸着材が充填された吸着塔（２）に導入し、ガス吸着を行う工程（Ｃ）と、
工程（Ｃ）で吸着塔（２）に吸着されることなく排気されたガス（ｇ２）を高酸素濃度ガスとして回収する工程（Ｄ）を有することを特徴とする酸素分離方法。 A step (A) in which air is introduced into an adsorption tower (1) filled with an adsorbent that mainly adsorbs oxygen, and gas adsorption is performed by an adsorption tower using a pressure swing adsorption method;
A step (B) of desorbing the gas (g 1 ) adsorbed on the adsorption tower (1) in the step (A);
The gas (g 1 ) desorbed in the step (B) is introduced into an adsorption tower (2) which is a pressure swing adsorption system and is filled with an adsorbent that mainly adsorbs nitrogen, and performs gas adsorption. Step (C),
An oxygen separation method comprising a step (D) of recovering a gas (g 2 ) exhausted without being adsorbed by the adsorption tower (2) in the step (C) as a high oxygen concentration gas. 工程（Ａ）のために吸着塔（１）に導入される前の空気と、工程（Ａ）で吸着塔（１）に吸着されることなく排気されたガス（ｇ３）を熱交換し、ガス（ｇ３）の顕熱で前記空気を昇温させることを特徴とする請求項１に記載の酸素分離方法。 Heat exchange between the air before being introduced into the adsorption tower (1) for the step (A) and the gas (g 3 ) exhausted without being adsorbed by the adsorption tower (1) in the step (A); The oxygen separation method according to claim 1, wherein the temperature of the air is raised by sensible heat of gas (g 3 ). 工程（Ｃ）で吸着塔（２）に吸着された後、脱着されたガス（ｇ４）を、工程（Ａ）のために吸着塔（１）に導入される前の空気に混合することを特徴とする請求項１又は２に記載の酸素分離方法。 After adsorbing to the adsorption tower (2) in the step (C), the desorbed gas (g 4 ) is mixed with the air before being introduced into the adsorption tower (1) for the step (A). The oxygen separation method according to claim 1 or 2, characterized in that ２基の吸着塔（１）で工程（Ａ）と工程（Ｂ）を交互に行う酸素分離方法であって、一方の吸着塔（１）の工程（Ｂ）で脱着されたガス（ｇ１）と、工程（Ａ）のために他方の吸着塔（１）に導入される前の空気を熱交換し、ガス（ｇ１）の顕熱で前記空気を昇温させることを特徴とする請求項１〜３のいずれかに記載の酸素分離方法。 An oxygen separation method in which the step (A) and the step (B) are alternately performed in two adsorption towers (1), and the gas (g 1 ) desorbed in the step (B) of one adsorption tower ( 1 ) The air before being introduced into the other adsorption tower (1) for the step (A) is subjected to heat exchange, and the temperature of the air is raised by sensible heat of the gas (g 1 ). The oxygen separation method according to any one of 1 to 3. 酸素を主として吸着する吸着材が充填された吸着塔（１）を備えた圧力スイング吸着装置（１０）と、
吸着塔（１）に空気を供給する送風手段（４）と、
吸着塔（１）に吸着されたガス（ｇ１）を脱着時に排気する排気手段（５）と、
窒素を主として吸着する吸着材が充填され、排気手段（５）により吸着塔（１）から排気されたガス（ｇ１）が供給される吸着塔（２）を備えた圧力スイング吸着装置（２０）を備え、
吸着塔（２）に吸着されることなく排気されたガス（ｇ２）が高酸素濃度ガスとして回収されるようにしたことを特徴とする酸素分離設備。 A pressure swing adsorption device (10) comprising an adsorption tower (1) filled with an adsorbent that mainly adsorbs oxygen;
A blowing means (4) for supplying air to the adsorption tower (1);
An exhaust means (5) for exhausting the gas (g 1 ) adsorbed on the adsorption tower (1) at the time of desorption;
Pressure swing adsorption device (20) provided with an adsorption tower (2) filled with an adsorbent mainly adsorbing nitrogen and supplied with gas (g 1 ) exhausted from the adsorption tower (1) by the exhaust means (5) With
An oxygen separation facility characterized in that the gas (g 2 ) exhausted without being adsorbed by the adsorption tower (2) is recovered as a high oxygen concentration gas. さらに、吸着塔（１）に導入される前の空気と、吸着塔（１）に吸着されることなく排気されたガス（ｇ３）を熱交換する熱交換器（２４）を備えることを特徴とする請求項５に記載の酸素分離設備。 Furthermore, it is provided with a heat exchanger (24) for exchanging heat between air before being introduced into the adsorption tower (1) and gas (g 3 ) exhausted without being adsorbed by the adsorption tower (1). The oxygen separation facility according to claim 5. 吸着塔（２）に吸着された後、脱着されたガス（ｇ４）の排気管（１７）を、送風手段（４）が設けられた空気供給管（８）であって、送風手段（４）の上流側の管部位置に接続したことを特徴とする請求項５又は６に記載の酸素分離設備。 After being adsorbed to the adsorption tower (2), the exhaust pipe of the desorbed gas (g 4) to (17), an air supply pipe blowing means (4) is provided (8), blowing means (4 The oxygen separation equipment according to claim 5 or 6, wherein the oxygen separation equipment is connected to the upstream pipe position. 吸着工程と脱着工程を交互に行う２基の吸着塔（１）を備えた酸素分離設備であって、さらに、一方の吸着塔（１）から脱着されたガス（ｇ１）と、他方の吸着塔（１）に導入される前の空気を熱交換する熱交換器（２５）を備えることを特徴とする請求項５〜７のいずれかに記載の酸素分離設備。 An oxygen separation facility comprising two adsorption towers (1) for alternately performing an adsorption process and a desorption process, further comprising a gas (g 1 ) desorbed from one adsorption tower ( 1 ) and the other adsorption The oxygen separation facility according to any one of claims 5 to 7, further comprising a heat exchanger (25) for exchanging heat of air before being introduced into the tower (1). 圧力スイング吸着装置（１０）は、２基の吸着塔（１ａ），（１ｂ）と、これら吸着塔（１ａ），（１ｂ）で吸着工程と脱着工程を交互に行うためにガスを給排気することができる配管系を備え、該配管系に送風手段（４）と排気手段（５）が設けられ、
圧力スイング吸着装置（２０）は、２基の吸着塔（２ａ），（２ｂ）と、これら吸着塔（２ａ），（２ｂ）で吸着工程と脱着工程を交互に行うためにガスを給排気することができる配管系を備えることを特徴とする請求項８に記載の酸素分離設備。 The pressure swing adsorption device (10) supplies and exhausts gas in order to alternately perform an adsorption process and a desorption process in the two adsorption towers (1a) and (1b) and these adsorption towers (1a) and (1b). A piping system that can be provided with a blowing means (4) and an exhaust means (5),
The pressure swing adsorption device (20) supplies and exhausts gas in order to alternately perform an adsorption process and a desorption process in the two adsorption towers (2a) and (2b) and these adsorption towers (2a) and (2b). The oxygen separation facility according to claim 8, further comprising a piping system capable of performing the operation.
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