JPH0731828A - Gas separation method - Google Patents
Gas separation methodInfo
- Publication number
- JPH0731828A JPH0731828A JP5202912A JP20291293A JPH0731828A JP H0731828 A JPH0731828 A JP H0731828A JP 5202912 A JP5202912 A JP 5202912A JP 20291293 A JP20291293 A JP 20291293A JP H0731828 A JPH0731828 A JP H0731828A
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- JP
- Japan
- Prior art keywords
- gas
- adsorption tank
- adsorption
- outlet
- inlet
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、圧力スイング吸着法
（ＰＳＡ法）によって易吸着性ガスと難吸着性ガスを成
分とする混合ガスから難吸着性ガスを分離するガスの分
離方法に関する。更に詳しくは、該方法に用いる吸着槽
中の吸着剤層の温度分布を均一化し、吸着剤のガス分離
能力を向上させる方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas separation method for separating a hardly-adsorptive gas from a mixed gas containing an easily-adsorptive gas and a hardly-adsorptive gas by a pressure swing adsorption method (PSA method). More specifically, it relates to a method of making the temperature distribution of the adsorbent layer in the adsorption tank used in the method uniform and improving the gas separation ability of the adsorbent.
【０００２】[0002]
【従来の技術・発明が解決しようとする課題】易吸着性
ガスと難吸着性ガスを成分とする混合ガスから難吸着性
ガスを製品ガスとして取り出し、易吸着性ガスを脱着ガ
スとして排気するＰＳＡ法において、例えば、ゼオライ
トを吸着剤とし、酸素を製品ガスとして分離するＰＳＡ
法において、混合ガスとして空気を吸着槽へ加圧導入し
た場合、窒素がゼオライト細孔内へ優先的に吸着して、
吸着ガス１Ｎリットル当たり約０．２ｋｃａｌの吸着熱
量が発生する。発生した熱はガス流とともに吸着槽出口
側へ移動し、吸着槽外へ放出される。一方、吸着時の圧
力より減圧して窒素を脱着し、吸着剤を再生する場合
は、吸着時とは逆に吸熱される。この断熱吸熱現象によ
り吸着剤温度が降下し、その程度は、吸着された窒素量
により影響され、吸着槽入口側に近い吸着剤程冷却され
ることとなる。2. Description of the Related Art PSA for extracting a hard-to-adsorb gas as a product gas from a mixed gas containing a hard-to-adsorb gas and a hard-to-adsorb gas as a component gas, and exhausting the hard-to-adsorb gas as a desorption gas In the method, for example, PSA for separating zeolite as an adsorbent and oxygen as a product gas
In the method, when air is introduced under pressure into the adsorption tank as a mixed gas, nitrogen is preferentially adsorbed in the zeolite pores,
An adsorption heat amount of about 0.2 kcal is generated per 1 N of the adsorption gas. The generated heat moves to the outlet side of the adsorption tank together with the gas flow and is released outside the adsorption tank. On the other hand, when desorbing nitrogen by depressurizing it from the pressure at the time of adsorption to regenerate the adsorbent, heat is absorbed contrary to the time of adsorption. Due to this adiabatic endothermic phenomenon, the temperature of the adsorbent is lowered, and the degree thereof is influenced by the amount of adsorbed nitrogen, and the adsorbent closer to the inlet side of the adsorption tank is cooled.
【０００３】通常、吸着工程にて発生した熱量と脱着工
程にて吸熱される熱量を比較すると、発熱量は、ガス流
に伴って一部系外に放出されるため、脱着時の吸熱量の
方が大きくなる。このため吸着槽内温度は時間の経過と
ともに低下する。この温度は、ＰＳＡ操作中においては
吸着槽に導入される原料空気の温度が３０℃以上の場合
においても、吸着・脱着の行われている吸着槽の原料空
気入口部に近い部分では−１０℃以下の温度にまで下が
る場合がある。この温度低下は、吸着剤のガス吸着力の
増加をもたらすものの、その為にかえって脱着がしにく
くなり残留ガスが吸着剤に蓄積することとなる。その結
果、窒素と酸素の分離効率が低下するという不都合が生
じる。Usually, comparing the amount of heat generated in the adsorption process with the amount of heat absorbed in the desorption process, the calorific value is partly released to the outside of the system along with the gas flow. It becomes bigger. Therefore, the temperature in the adsorption tank decreases with the passage of time. Even if the temperature of the raw material air introduced into the adsorption tank during PSA operation is 30 ° C. or higher, this temperature is −10 ° C. in the portion close to the raw material air inlet of the adsorption tank where adsorption / desorption is performed. The temperature may drop to the following temperatures. This decrease in temperature brings about an increase in the gas adsorbing power of the adsorbent, but on the contrary, desorption becomes difficult and residual gas accumulates in the adsorbent. As a result, there arises a disadvantage that the separation efficiency of nitrogen and oxygen decreases.
【０００４】この吸着槽内温度の不均一化を防止する方
法としては、 温度低下の著しい部分に電熱ヒーターを設置する方法
（特開平４−３２２７１４号公報）、 吸着槽の軸方向を多数の金属板で区切り、塔頂部の熱
を下方に移行して脱着時の温度補給を行う方法、あるい
は ヒートポンプで他の吸着塔との間の熱交換を行う方法
等があり、吸着槽の機械的構造を種々工夫することによ
り吸着槽の入口部と出口部の温度を均一化させる試みが
なされているが、いずれの方法も充分な効果が得られず
実用化されていない。As a method for preventing the temperature nonuniformity in the adsorption tank, a method of installing an electric heater in a portion where the temperature drops significantly (Japanese Patent Laid-Open No. 4-322714), and a large number of metals in the axial direction of the adsorption tank are used. There are methods such as separating with a plate and transferring the heat at the top of the tower downward to replenish the temperature at the time of desorption, or a method of exchanging heat with other adsorption towers with a heat pump. Attempts have been made to make the temperature at the inlet and outlet of the adsorption tank uniform by various means, but none of them has been put to practical use because the sufficient effect cannot be obtained.
【０００５】また、特開昭６１−２６３６１６号公報に
は、高温になった吸着槽の出口部にある製品ガスを吸着
槽内に設けられた配管内を通過させることによって吸着
槽の原料ガス入口部の低温になったゾーンに製品ガスの
熱を供給し、吸着槽内の温度を均一化し、吸着剤の性能
の向上をはかっているが熱交換量には限界があり、完全
な方法とは言い難い。一方、吸着槽内の温度の不均一化
による分離能力の低下を防止する方法として、特開平４
−２９３５１３号公報では、吸着槽に充填する吸着剤を
上流側と下流側で種類を変えることによって高温特性と
低温特性にあったもので使い分けて分離性能の向上を試
みてはいるが、これとても決定的な方法ではない。Further, in Japanese Patent Laid-Open No. 61-263616, the raw material gas inlet of the adsorption tank is obtained by passing the product gas at the outlet of the adsorption tank, which has become hot, through a pipe provided in the adsorption tank. The heat of the product gas is supplied to the zone where the temperature becomes low, and the temperature inside the adsorption tank is made uniform to improve the performance of the adsorbent, but there is a limit to the amount of heat exchange, and it is not a complete method. Hard to say. On the other hand, as a method for preventing the deterioration of the separation ability due to the non-uniform temperature in the adsorption tank, there is disclosed in Japanese Patent Laid-Open No.
In JP-A-293513, the type of the adsorbent to be filled in the adsorption tank is changed between the upstream side and the downstream side depending on the high temperature characteristic and the low temperature characteristic, and the separation performance is attempted to be improved by using them properly. Not the definitive way.
【０００６】[0006]
【課題を解決するための手段】本発明者等は、混合ガス
を原料とし、易吸着性ガスを吸着除去して難吸着性ガス
を製品ガスとして取り出すＰＳＡ法による難吸着性ガス
の分離法において、吸着槽入口部の易吸着性ガスの吸着
量が出口部に比べて常に多い状態にあることが吸着槽の
出入口間での温度差をもたらしている原因と考えた。そ
こで、吸着工程に先立ち行われる脱着・再生工程の終了
後の吸着槽の圧力を吸着工程時の圧力に近い圧力にまで
上昇させる復圧工程時に、復圧の行われている吸着槽の
出口部に加えて入口部にも製品ガスの一部である難吸着
性ガスを流入させ、該吸着槽入口部の易吸着性ガス濃度
を低下させ、吸着熱の急激な発生を抑制することにより
吸着槽出入口間の温度差を減少させる解決法を試みた。Means for Solving the Problems The present inventors have proposed a method for separating a hardly adsorbed gas by a PSA method, which uses a mixed gas as a raw material and adsorbs and removes an easily adsorbed gas to take out the hardly adsorbed gas as a product gas. The reason why the adsorption amount of the easily adsorbed gas at the inlet of the adsorption tank is always larger than that at the outlet is considered to be the cause of the temperature difference between the inlet and outlet of the adsorption tank. Therefore, during the recompression process that raises the pressure of the adsorption tank after the desorption / regeneration process that is performed prior to the adsorption process to a pressure close to the pressure during the adsorption process, the outlet of the adsorption tank where recompression is performed. In addition to this, the adsorbent gas, which is a part of the product gas, also flows into the inlet to reduce the concentration of the easily adsorbable gas at the inlet of the adsorption tank, and suppress the rapid generation of heat of adsorption An attempt was made to reduce the temperature difference between the entrance and the exit.
【０００７】その結果、吸着槽の入口部には難吸着性ガ
ス（製品ガス）を流入させることなく吸着槽の出口部に
のみ難吸着性ガス（製品ガス）を流入させて吸着圧に近
い圧力にまで復圧する従来の方法に比べて、吸着槽入口
部における温度の低下を少なくさせることができるこ
と、吸着槽出口部の温度も低くなるため出入口間の温度
差を小さくすることができ、吸着槽中の吸着剤層の温度
分布の均一化ができること、また、分離して得られる難
吸着性ガスである製品ガスの取得量も増加させることが
できることを見い出し本発明に到達した。As a result, the refractory gas (product gas) is not allowed to flow into the inlet of the adsorption tank, but the refractory gas (product gas) is allowed to flow into only the outlet of the adsorption tank. Compared with the conventional method of re-pressurizing up to 1, the temperature drop at the inlet of the adsorption tank can be reduced, and the temperature at the outlet of the adsorption tank is also reduced, so the temperature difference between the inlet and outlet can be reduced, and the adsorption tank can be reduced. They have found that the temperature distribution of the adsorbent layer in the inside can be made uniform, and that the amount of product gas, which is a hardly adsorbed gas obtained by separation, can be increased, and reached the present invention.
【０００８】すなわち、本発明の要旨は、吸着剤を充填
した複数の吸着槽を用いてＰＳＡ法により、易吸着性ガ
スと難吸着性ガスを成分とする混合ガスから易吸着性ガ
スを吸着除去し、難吸着性ガスを製品ガスとして分離す
るガスの分離方法において、吸着工程により吸着槽の出
口部より流出する製品ガスの一部を復圧工程中の他の吸
着槽の出口部および入口部に流入させることにより該吸
着槽の入口部に生じた低温部と出口部に生じた高温部の
温度差を減少させることを特徴とするガスの分離方法に
関する。That is, the gist of the present invention is to adsorb and remove the easily adsorbed gas from the mixed gas containing the easily adsorbed gas and the hardly adsorbed gas by the PSA method using a plurality of adsorption tanks filled with an adsorbent. However, in the gas separation method for separating the hardly adsorbed gas as the product gas, the part of the product gas flowing out from the outlet of the adsorption tank in the adsorption step is partially exhausted from the outlet and the inlet of the other adsorption tank during the decompression step. The present invention relates to a gas separation method, characterized in that the temperature difference between the low temperature portion generated at the inlet of the adsorption tank and the high temperature portion generated at the outlet of the adsorption tank is reduced.
【０００９】本発明の方法によれば、吸着工程に先立
ち、脱着・再生工程終了後の吸着槽の圧力を吸着工程時
の圧力に近い圧力にまで上昇させる復圧工程時に、復圧
の行われている吸着槽の出口部および入口部に難吸着性
ガス（製品ガス）を流入させるという簡単な操作で、該
吸着槽入口部の易吸着性ガス濃度を低下させることがで
き、吸着工程で生じる易吸着性ガスの吸着による局所的
な発熱量を少なくすることができる。According to the method of the present invention, prior to the adsorption step, the pressure is restored in the pressure restoration step in which the pressure in the adsorption tank after the desorption / regeneration step is increased to a pressure close to the pressure in the adsorption step. The concentration of the easily adsorbable gas at the inlet of the adsorption tank can be reduced by a simple operation of flowing the hardly adsorbable gas (product gas) into the outlet and the inlet of the adsorbing tank. It is possible to reduce the amount of heat generated locally due to the adsorption of the easily adsorbable gas.
【００１０】復圧工程時に吸着槽の出口部および入口部
に流入させる難吸着性ガスとしては、吸着工程により吸
着槽の出口部より流出する製品ガスの一部が使用され
る。このような製品ガスとしては、吸着工程中の吸着槽
の出口より流出している難吸着性ガスあるいは、吸着工
程終了後の吸着槽出口部に残留する難吸着性ガスを出口
部より流出させて用いることが可能である。後者の場合
には吸着槽出口部に残留する難吸着性ガスの量に限りが
あるため、それを脱着・再生工程の終了した吸着槽の出
口部および入口部に導入しても入口部に存在する易吸着
性ガス濃度を低下させるという効果は小さい。しかし、
前者の場合は難吸着性ガス量が充分であるためにその効
果を充分引き出すことができ、本発明に好ましく用いら
れる。A part of the product gas flowing out from the outlet of the adsorption tank in the adsorption step is used as the hardly adsorbing gas which is made to flow into the outlet and the inlet of the adsorption tank in the pressure recovery step. As such a product gas, the hardly adsorbed gas flowing out from the outlet of the adsorption tank during the adsorption process or the hardly adsorbed gas remaining in the outlet portion of the adsorption tank after the adsorption process is allowed to flow out from the outlet portion. It can be used. In the latter case, the amount of hardly adsorbed gas remaining at the outlet of the adsorption tank is limited, so even if it is introduced into the outlet and inlet of the adsorption tank after the desorption / regeneration process, it remains at the inlet. The effect of lowering the concentration of the easily adsorbed gas is small. But,
In the former case, the amount of the hardly-adsorptive gas is sufficient, so that the effect can be sufficiently brought out, and it is preferably used in the present invention.
【００１１】前者の方法によれば、真空再生法の場合は
真空ポンプで真空排気した後に、常圧再生法では大気圧
まで吸着槽内の圧力を放圧させた後、すなわち吸着工程
前の脱着・再生工程終了後の復圧工程時に、吸着工程中
の別の吸着槽の出口より流出している製品ガスである難
吸着性ガスの一部を吸着槽の出口部と入口部から同時に
流入させる。According to the former method, in the case of the vacuum regeneration method, after vacuum evacuation with a vacuum pump, in the normal pressure regeneration method, the pressure in the adsorption tank is released to atmospheric pressure, that is, the desorption before the adsorption step.・ During the pressure recovery step after the regeneration step, part of the non-adsorbent gas, which is the product gas flowing out from the outlet of another adsorption tank during the adsorption step, is introduced at the same time from the outlet and inlet of the adsorption tank. .
【００１２】具体的なガスの流れを示す工程図として、
図１に従来の方法を、図２に本発明の方法である吸着工
程中の吸着槽の出口部より流出している製品ガスである
難吸着性ガスの一部を脱着・再生工程の終了した吸着槽
の出口部と入口部から同時に流入させて吸着圧力に近い
圧力まで復圧させる方法の操作ステップを示した。[0012] As a process diagram showing a specific gas flow,
FIG. 1 shows the conventional method, and FIG. 2 shows that the desorption / regeneration step is completed for a part of the hardly adsorbed gas which is the product gas flowing out from the outlet of the adsorption tank during the adsorption step of the present invention. The operational steps of the method of simultaneously inflowing from the outlet and the inlet of the adsorption tank to restore the pressure to a pressure close to the adsorption pressure were shown.
【００１３】以下に各々の方法により空気から酸素を取
得する場合を例に説明する。まず、図１に基づき従来の
方法による場合を説明する。図１は、ゼオライトを充填
した３つの吸着槽からなる、空気から酸素を製造する装
置のガスの流れを表す操作ステップを示す。 ステップ−１ 吸着槽Ａは、空気ブロアーにより昇圧した空気が送入
され、窒素を吸着させながら出口部より濃縮された酸素
を製品酸素として流出させる（吸着工程）、 その間、吸着槽Ｂは吸着槽Ａより流出した製品酸素の
一部を出口部より流入させて吸着圧力に近い圧力まで復
圧させる（復圧工程）、 吸着槽Ｃは吸着した窒素を真空ポンプにて脱着排気
し、吸着剤を再生させる（脱着・再生工程）、 上記の工程からなるステップを３つの吸着槽で順次行う
ことによりステップ−２、ステップ−３へと続け、ステ
ップ−３にて１サイクルが終了する。操作時間は一般的
には各ステップで各工程０．５〜２分間ずつ行われ、
１．５〜６分間で１サイクルが終了する。復圧工程にお
いては、製品酸素として取得される酸素ガス量の１／２
〜１０倍量の酸素が流入され、吸着圧力に近い圧力まで
復圧させる。Hereinafter, the case where oxygen is obtained from air by each method will be described as an example. First, the case of the conventional method will be described with reference to FIG. FIG. 1 shows the operating steps representing the gas flow of an apparatus for producing oxygen from air, which consists of three adsorption tanks filled with zeolite. Step-1 In the adsorption tank A, the air whose pressure has been increased by the air blower is fed, and while adsorbing nitrogen, the concentrated oxygen is discharged from the outlet as product oxygen (adsorption step). Part of the product oxygen flowing out of A is made to flow in from the outlet to recompress to a pressure close to the adsorption pressure (recompression process), and adsorption tank C desorbs and exhausts the adsorbed nitrogen with a vacuum pump to remove the adsorbent. Regeneration (desorption / regeneration step) and the steps consisting of the above steps are sequentially performed in the three adsorption tanks to continue to step-2 and step-3. At step-3, one cycle is completed. The operation time is generally 0.5 to 2 minutes for each step in each step,
One cycle is completed in 1.5 to 6 minutes. In the recompression process, 1/2 of the amount of oxygen gas obtained as product oxygen
About 10 times as much oxygen is flowed in, and the pressure is restored to a pressure close to the adsorption pressure.
【００１４】図２は、前記のとおり、脱着・再生工程の
終了した吸着槽の圧力を吸着工程時の圧力に近い圧力ま
で復圧させる復圧工程において、吸着工程中の吸着槽の
出口部より流出している製品酸素の一部を復圧工程中の
吸着槽の出口部と入口部とから同時に流入させて行う本
発明の方法の操作ステップを示したものである。 ステップ−１ 吸着槽Ａは、入口部より空気を流入させて窒素を吸着
剤に吸着させながら出口部より濃縮された酸素を流出さ
せる（吸着工程）、 吸着槽Ｂは、吸着工程中の吸着槽Ａの出口部から流出
される製品酸素の一部を吸着槽の出口部および入口部よ
り同時に流入させる（復圧工程）、 吸着槽Ｃは入口部より窒素を脱着させ、吸着剤を再生
する（脱着・再生工程）、 上記の工程からなるステップを３つの吸着槽で順次行う
ことによりステップ−２、ステップ−３へと続け、ステ
ップ−３にて１サイクル終了する。操作時間は一般的に
は各ステップで各工程０．５〜２分間ずつ行われ、１．
５〜６分間で１サイクルが終了する。FIG. 2 shows, as described above, that the pressure in the adsorption tank after the desorption / regeneration step is restored to a pressure close to the pressure in the adsorption step, from the outlet of the adsorption tank during the adsorption step. It shows the operation steps of the method of the present invention in which a part of the product oxygen flowing out is caused to flow in simultaneously from the outlet and the inlet of the adsorption tank during the decompression process. Step-1 The adsorption tank A allows air to flow in from the inlet to adsorb nitrogen to the adsorbent while flowing out concentrated oxygen from the outlet (adsorption step). The adsorption tank B is an adsorption tank during the adsorption step. Part of the product oxygen flowing out from the outlet of A is made to flow in simultaneously from the outlet and the inlet of the adsorption tank (recompression step), and adsorption tank C desorbs nitrogen from the inlet to regenerate the adsorbent ( Desorption / regeneration step), the steps consisting of the above steps are sequentially performed in the three adsorption tanks to continue to step-2 and step-3, and one cycle is completed at step-3. The operation time is generally 0.5 to 2 minutes for each step and 1.
One cycle is completed in 5 to 6 minutes.
【００１５】本発明においては、各ステップの復圧工程
において、吸着工程中の別の吸着槽出口部から流出され
る製品ガスの一部を吸着槽の出口部ばかりではなく入口
部へも流入させることを特徴とする。これにより復圧工
程において吸着槽入口部の易吸着性ガス濃度を低下させ
ることができ、吸着工程で生じる易吸着性ガスの吸着に
よる局所的な発熱量を少なくすることができる。In the present invention, in the pressure-reducing step of each step, a part of the product gas flowing out from another adsorption tank outlet during the adsorption step is caused to flow not only into the adsorption tank outlet but also into the inlet. It is characterized by As a result, it is possible to reduce the concentration of the easily adsorbable gas at the inlet of the adsorption tank in the recompression step, and it is possible to reduce the amount of local heat generation due to the adsorption of the easily adsorbable gas generated in the adsorption step.
【００１６】復圧工程中の吸着槽の入口部と出口部の両
方へ流入させる製品ガスは、別の吸着工程中の吸着槽よ
り流出される製品ガスの一部を用いる。ここで使用され
る製品ガス量としては、吸着性ガスの種類、吸着圧力お
よび吸着槽の大きさ等の条件により適宜決定されるが、
通常、吸着工程中の吸着槽より流出する製品ガスの３０
〜９０％を復圧工程中の吸着槽の出口部と入口部へ流入
させる。この場合、吸着槽入口部へは、出口部に流入さ
せるガス量の１／３０〜１倍量の難吸着性ガス（製品ガ
ス）を流入させて復圧させる。入口部への流入量が１／
３０倍量より少ない量では、製品ガスの一部を流入させ
て吸着槽入口部の易吸着性ガス濃度を低下させることに
より吸着槽入口部の温度を低下させる効果が充分得られ
ない。一方、１倍量より過剰に流入させると吸着槽入口
部の吸着剤温度の低下を防止することはできるが、易吸
着性ガスが過剰の難吸着性ガスとともに吸着槽出口部へ
移動し、次の吸着工程において難吸着性ガス中に混入す
るため、製品となるに充分な濃度を有するガス取得量が
減少することになる。A part of the product gas discharged from the adsorption tank during another adsorption step is used as the product gas which is made to flow into both the inlet and the outlet of the adsorption tank during the recompression step. The amount of product gas used here is appropriately determined according to conditions such as the type of adsorptive gas, the adsorption pressure and the size of the adsorption tank,
Normally, 30 product gases flowing out of the adsorption tank during the adsorption process
About 90% is made to flow into the outlet and inlet of the adsorption tank during the recompression process. In this case, 1/30 to 1 times the amount of gas that is difficult to adsorb (product gas) that flows into the outlet is introduced into the inlet of the adsorption tank to restore the pressure. The amount of inflow to the inlet is 1 /
If the amount is less than 30 times, the effect of lowering the temperature at the inlet of the adsorption tank cannot be sufficiently obtained by inflowing a part of the product gas to reduce the concentration of the easily adsorbable gas at the inlet of the adsorption tank. On the other hand, when the amount of the adsorbent is more than 1 time, the temperature of the adsorbent at the inlet of the adsorption tank can be prevented from decreasing, but the easily adsorbed gas moves to the outlet of the adsorption tank together with the excessive amount of the hardly adsorbed gas. Since it is mixed in the hardly adsorbed gas in the adsorption step, the amount of gas having a sufficient concentration to become a product is reduced.
【００１７】例えば、空気より酸素を分離する場合、復
圧工程において難吸着性ガスである酸素を吸着槽入口部
に流入させる量は、吸着槽出口部に流入させる酸素量の
１／３０〜１倍量であり、吸着槽内のゼオライトモレキ
ュラーシーブ１ｋｇ当たり０．００３〜０．２Ｎｍ3 ／
Ｈ、好ましくは０．００５〜０．１５Ｎｍ3 ／Ｈの範囲
が適量である。また、吸着圧力としては５００ｍｍＨ2
Ｏ／ｃｍ2 〜３ｋｇ／ｃｍ2 Ｇの圧力が好適である。上
記では、空気を原料とする酸素の製造方法についてのみ
述べたが、同様にしてゼオライトモレキュラーシーブを
充填剤として用いる他のガス、例えは、アルゴンガスや
水素の分離・精製方法においても吸着槽内の温度変化を
抑制することが可能となり分離性能の向上を図ることが
できる。For example, in the case of separating oxygen from air, the amount of oxygen, which is a difficult-to-adsorb gas, to flow into the adsorption tank inlet in the recompression step is 1/30 to 1 of the amount of oxygen to flow into the adsorption tank outlet. Double the amount, and 0.003 to 0.2 Nm 3 / kg of zeolite molecular sieve in the adsorption tank
An appropriate amount is H, preferably 0.005 to 0.15 Nm 3 / H. The adsorption pressure is 500 mmH 2.
A pressure of O / cm 2 to 3 kg / cm 2 G is suitable. In the above, only the method for producing oxygen using air as a raw material is described, but similarly, other gas using zeolite molecular sieve as a filler, for example, in the adsorption tank also in the method of separating and purifying argon gas or hydrogen. It is possible to suppress the temperature change of the above and improve the separation performance.
【００１８】[0018]
【実施例】以下に実施例および比較例をあげて本発明を
詳細に説明するが本発明はこれらにより何等限定される
ものではない。The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these.
【００１９】実施例１〜３ 直径８００ｍｍφ、充填層高さ２０００ｍｍの吸着槽３
槽にＣａＡ型ゼオライトを各々６００ｋｇずつ充填し
た。吸着槽に空気ブロアーで５００ｍｍＨ2 Ｏの圧力ま
で昇圧した空気を導入するとともに、真空ポンプで２３
０ｔｏｒｒまで真空脱着再生しながら図２に示したステ
ップ−１〜３に従って、１ステップ当たり６０秒、１サ
イクル当たり６０秒×３＝１８０秒の操作時間でＰＳＡ
操作した。このとき、吸着層入口部の空気温度を２０℃
に制御し、復圧工程での吸着槽出口部および入口部への
製品酸素の流入量は表１記載の量とした。ＰＳＡ操作中
のゼオライト層内の温度を測定したところ、ゼオライト
層内の温度分布は図３の、、に示すとおりであっ
た。濃度９３Ｖｏｌ％の酸素発生量は表１に示すとおり
であった。Examples 1 to 3 Adsorption tank 3 having a diameter of 800 mm and a packed bed height of 2000 mm
The tank was filled with 600 kg each of CaA type zeolite. Air having a pressure of 500 mmH 2 O increased by an air blower was introduced into the adsorption tank, and a vacuum pump operated 23
According to steps -1 to 3 shown in FIG. 2, the PSA was operated for 60 seconds per step, 60 seconds per cycle × 3 = 180 seconds while performing vacuum desorption regeneration to 0 torr.
Operated. At this time, set the air temperature at the inlet of the adsorption layer to 20 ° C.
The amount of product oxygen flowing into the adsorption tank outlet and inlet in the pressure recovery step was set to the amount shown in Table 1. When the temperature in the zeolite layer during the PSA operation was measured, the temperature distribution in the zeolite layer was as shown by and in FIG. The oxygen generation amount at a concentration of 93 Vol% was as shown in Table 1.
【００２０】[0020]
【表１】 [Table 1]
【００２１】これにより、復圧工程において製品酸素の
一部を吸着槽出口部および入口部に同時に流入させるこ
とにより、ゼオライト層内の温度分布を平均化させるこ
とが可能となった。As a result, it becomes possible to average the temperature distribution in the zeolite layer by causing a part of the product oxygen to flow into the outlet and the inlet of the adsorption tank at the same time in the recompression step.
【００２２】比較例１ 直径８００ｍｍφ、充填層高さ２０００ｍｍの吸着槽３
槽にＣａＡ型ゼオライトを各々６００ｋｇずつ充填し
た。吸着槽に空気ブロアーで５００ｍｍＨ2 Ｏの圧力ま
で昇圧した空気を導入するとともに、真空ポンプで２３
０ｔｏｒｒまで真空脱着再生しながら図１に示す従来の
方法によるステップ−１〜３を繰り返し、１ステップ当
たり６０秒、１サイクル当たり６０秒×３＝１８０秒の
操作時間でＰＳＡ操作を行った。復圧工程での吸着槽出
口部への製品酸素の流入量は１４０Ｎｍ3 ／Ｈとした。
このとき、吸着槽入口部における空気温度は２０℃であ
った。この結果、ゼオライト層内の温度分布は図３の
のようになり、酸素発生量は濃度９３Ｖｏｌ％の酸素が
２５．６Ｎｍ3 ／Ｈで得られた。酸素取得収率は４４％
であった。Comparative Example 1 Adsorption tank 3 having a diameter of 800 mm and a packed bed height of 2000 mm
The tank was filled with 600 kg each of CaA type zeolite. Air having a pressure of 500 mmH 2 O increased by an air blower was introduced into the adsorption tank, and a vacuum pump operated 23
While performing vacuum desorption regeneration to 0 torr, steps -1 to 3 according to the conventional method shown in FIG. 1 were repeated, and PSA operation was performed for 60 seconds per step, 60 seconds per cycle × 3 = 180 seconds. The inflow amount of product oxygen to the outlet of the adsorption tank in the recompression step was 140 Nm 3 / H.
At this time, the air temperature at the inlet of the adsorption tank was 20 ° C. As a result, the temperature distribution in the zeolite layer was as shown in FIG. 3, and the oxygen generation amount was oxygen at a concentration of 93 Vol% at 25.6 Nm 3 / H. Oxygen acquisition yield is 44%
Met.
【００２３】[0023]
【発明の効果】従来のＰＳＡ法によるガスの分離方法で
は吸着剤に易吸着性ガスが吸・脱着するとき発生する吸
・脱着熱により吸着槽の出入口間で温度差が生じてもそ
のままの温度条件で使用するか又は強制的に機械的な方
法で熱交換させて温度差を縮めて使用するしか方法がな
かった。本発明の方法によれば容易に吸着槽中の吸着剤
層の温度分布を均一化してガスを吸・脱着させることが
できる。その結果、安定した吸着剤の使用が可能となる
とともに、吸着剤の分離効率を向上させることもでき、
経済的に有利にガスの分離ができる。According to the conventional gas separation method by the PSA method, even if a temperature difference occurs between the inlet and outlet of the adsorption tank due to the heat of adsorption and desorption generated when the easily adsorbable gas is adsorbed and desorbed by the adsorbent, the temperature remains unchanged. There was no choice but to use under conditions or to force heat exchange by a mechanical method to reduce the temperature difference before use. According to the method of the present invention, it is possible to easily make the temperature distribution of the adsorbent layer in the adsorption tank uniform and adsorb and desorb the gas. As a result, it is possible to use a stable adsorbent, it is also possible to improve the separation efficiency of the adsorbent,
Gas can be separated economically.
【図１】図１は、従来法によるＰＳＡ操作ステップの概
略図である。FIG. 1 is a schematic diagram of conventional PSA operating steps.
【図２】図２は、本発明の方法によるＰＳＡ操作ステッ
プの概略図である。FIG. 2 is a schematic diagram of PSA operating steps according to the method of the present invention.
【図３】図３は、実施例１〜３および比較例１の条件下
でのＰＳＡ操作中における吸着槽の吸着剤充填層高さと
吸着剤温度を示す図である。FIG. 3 is a diagram showing adsorbent packed bed height and adsorbent temperature in an adsorption tank during PSA operation under the conditions of Examples 1 to 3 and Comparative Example 1.
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成５年９月１日[Submission date] September 1, 1993
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１６[Correction target item name] 0016
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１６】 復圧工程中の吸着槽の入口部と出口部の
両方へ流入させる製品ガスは、別の吸着工程中の吸着槽
より流出される製品ガスの一部を用いる。ここで使用さ
れる製品ガス量としては、吸着性ガスの種類、吸着圧力
および吸着槽の大きさ等の条件により適宜決定される
が、通常、吸着工程中の吸着槽より流出する製品ガスの
３０〜９０％を復圧工程中の吸着槽の出口部と入口部へ
流入させる。この場合、吸着槽入口部へは、出口部に流
入させるガス量の１／３０〜１倍量の難吸着性ガス（製
品ガス）を流入させて復圧させる。入口部への流入量が
１／３０倍量より少ない量では、製品ガスの一部を流入
させて吸着槽入口部の易吸着性ガス濃度を低下させるこ
とにより吸着槽入口部の温度低下を防止する効果が充分
得られない。一方、１倍量より過剰に流入させると吸着
槽入口部の吸着剤温度の低下を防止することはできる
が、易吸着性ガスが過剰の難吸着性ガスとともに吸着槽
出口部へ移動し、次の吸着工程において難吸着性ガス中
に混入するため、製品となるに充分な濃度を有するガス
取得量が減少することになる。As the product gas which is made to flow into both the inlet and the outlet of the adsorption tank during the recompression step, a part of the product gas which is flowed out from the adsorption tank during another adsorption step is used. The amount of product gas used here is appropriately determined according to conditions such as the type of adsorptive gas, the adsorption pressure and the size of the adsorption tank, but normally, the amount of the product gas flowing out of the adsorption tank during the adsorption step is 30%. About 90% is made to flow into the outlet and inlet of the adsorption tank during the recompression process. In this case, 1/30 to 1 times the amount of gas that is difficult to adsorb (product gas) that flows into the outlet is introduced into the inlet of the adsorption tank to restore the pressure. When the amount of inflow to the inlet is less than 1/30 times, a part of the product gas is introduced to reduce the concentration of the easily adsorbable gas at the inlet of the adsorption tank to prevent the temperature of the inlet of the adsorption tank from decreasing. the effect of sufficiently not be obtained. On the other hand, when the amount of the adsorbent is more than 1 time, the temperature of the adsorbent at the inlet of the adsorption tank can be prevented from decreasing, but the easily adsorbed gas moves to the outlet of the adsorption tank together with the excessive amount of the hardly adsorbed gas. Since it is mixed in the hardly adsorbed gas in the adsorption step, the amount of gas having a sufficient concentration to become a product is reduced.
【手続補正２】[Procedure Amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１９[Correction target item name] 0019
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【００１９】実施例１〜３ 直径８００ｍｍφ、充填層高さ２０００ｍｍの吸着槽３
槽にＣａＡ型ゼオライトを各々６００ｋｇずつ充填し
た。吸着槽に空気ブロアーで５００ｍｍＨ２Ｏの圧力ま
で昇圧した空気を導入するとともに、真空ポンプで２３
０ｔｏｒｒまで真空脱着再生しながら図２に示したステ
ップ−１〜３に従って、１ステップ当たり６０秒、１サ
イクル当たり６０秒×３＝１８０秒の操作時間でＰＳＡ
操作した。このとき、吸着槽入口部の空気温度を２０℃
に制御し、復圧工程での吸着槽出口部および入口部への
製品酸素の流入量は表１記載の量とした。ＰＳＡ操作中
のゼオライト層内の温度を測定したところ、ゼオライト
層内の温度分布は図３の、、に示すとおりであっ
た。濃度９３Ｖｏ１％の酸素発生量は表１に示すとおり
であった。Examples 1 to 3 Adsorption tank 3 having a diameter of 800 mm and a packed bed height of 2000 mm
The tank was filled with 600 kg each of CaA type zeolite. Introduce the air whose pressure has been increased to 500 mmH 2 O with an air blower into the adsorption tank, and use a vacuum pump to remove the air.
According to steps -1 to 3 shown in FIG. 2, the PSA was operated for 60 seconds per step, 60 seconds per cycle × 3 = 180 seconds while performing vacuum desorption regeneration to 0 torr.
Operated. At this time, set the air temperature at the inlet of the adsorption tank to 20 ° C.
The amount of product oxygen flowing into the adsorption tank outlet and inlet in the pressure recovery step was set to the amount shown in Table 1. When the temperature in the zeolite layer during the PSA operation was measured, the temperature distribution in the zeolite layer was as shown by and in FIG. The oxygen generation amount at a concentration of 93 Vo1% was as shown in Table 1.
Claims (4)
ＰＳＡ法により、易吸着性ガスと難吸着性ガスを成分と
する混合ガスから易吸着性ガスを吸着除去し、難吸着性
ガスを製品ガスとして分離するガスの分離方法におい
て、吸着工程により吸着槽の出口部より流出する製品ガ
スの一部を復圧工程中の他の吸着槽の出口部および入口
部に流入させることにより該吸着槽の入口部に生じた低
温部と出口部に生じた高温部の温度差を減少させること
を特徴とするガスの分離方法。1. A PSA method using a plurality of adsorption tanks filled with an adsorbent to adsorb and remove an easily adsorbable gas from a mixed gas containing the easily adsorbable gas and the hardly adsorbable gas as components. In the method for separating a gas as a product gas, a part of the product gas flowing out from the outlet of the adsorption tank in the adsorption step is caused to flow into the outlet and the inlet of another adsorption tank during the recompression step. A method for separating gas, which comprises reducing a temperature difference between a low temperature portion generated at an inlet of an adsorption tank and a high temperature portion generated at an outlet thereof.
る製品ガスのうち、該吸着槽の入口部に流入させる量が
該吸着槽の出口部に流入させる量の１／３０〜１倍量で
ある請求項１記載の方法。2. The amount of product gas used for recompression of the adsorption tank after desorption and regeneration is made to flow into the inlet of the adsorption tank at 1/30 to 1 times the amount of the product gas to flow into the outlet of the adsorption tank. The method of claim 1 which is an amount.
ーブを用い、混合ガスとして空気を用いて易吸着性ガス
である窒素を吸着除去し、難吸着性ガスである酸素を製
品ガスとして分離する請求項１又は２記載の方法。3. A method for adsorbing and removing nitrogen, which is an easily adsorbed gas, by using zeolite molecular sieve as an adsorbent and using air as a mixed gas, and separating oxygen, which is a hardly adsorbed gas, as a product gas. 2. The method described in 2.
入させる製品ガスである酸素の量が、吸着槽中の吸着剤
１ｋｇあたり０．００３〜０．２Ｎｍ3 ／Ｈの範囲であ
る請求項３記載の方法。4. The amount of oxygen, which is a product gas, flowing into the inlet of the adsorption tank after desorption and regeneration is in the range of 0.003 to 0.2 Nm 3 / H per 1 kg of the adsorbent in the adsorption tank. Item 3. The method according to Item 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20291293A JP3405565B2 (en) | 1993-07-23 | 1993-07-23 | Gas separation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20291293A JP3405565B2 (en) | 1993-07-23 | 1993-07-23 | Gas separation method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0731828A true JPH0731828A (en) | 1995-02-03 |
| JP3405565B2 JP3405565B2 (en) | 2003-05-12 |
Family
ID=16465234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20291293A Expired - Lifetime JP3405565B2 (en) | 1993-07-23 | 1993-07-23 | Gas separation method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3405565B2 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56161819A (en) * | 1980-05-16 | 1981-12-12 | Kogyo Kaihatsu Kenkyusho | Improved method for continuously preparing highly concentrated oxygen from air on industrial basis |
| JPS6027606A (en) * | 1983-07-21 | 1985-02-12 | Nippon Sanso Kk | Preparation of nitrogen by pressure swing adsorption method |
-
1993
- 1993-07-23 JP JP20291293A patent/JP3405565B2/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56161819A (en) * | 1980-05-16 | 1981-12-12 | Kogyo Kaihatsu Kenkyusho | Improved method for continuously preparing highly concentrated oxygen from air on industrial basis |
| JPS6027606A (en) * | 1983-07-21 | 1985-02-12 | Nippon Sanso Kk | Preparation of nitrogen by pressure swing adsorption method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3405565B2 (en) | 2003-05-12 |
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