JP3646238B2 - Pressure swing adsorption method with pulse flow control - Google Patents

Description

【００２８】
本発明の請求項３の発明は、請求項１ないし請求項２記載のパルス流制御式圧力スイング吸着法において、自動弁を通過するガス量（Ｖｉ）を次式（２）により定めることを特徴とする。
【００２９】
【数４】

【００３０】
本発明の請求項４の発明は、請求項１ないし請求項３のいずれかに記載のパルス流制御式圧力スイング吸着法において、請求項１記載のパルス時間△ｔｉ、ポーズ時間△Ｚｉを下記の範囲とすることを特徴とする。
電磁弁：△ｔｉ；０．０５〜１．０秒
△Ｚｉ；０．１〜２．０秒
空気圧作動弁：
△ｔｉ；０．５〜３．０秒
△Ｚｉ；１．０〜６．０秒
【００３１】
【発明の実施の形態】
先ず図３に示す実験装置を用いて吸着塔２０に流（出）入するガスの挙動を調べた。
２０： 吸着塔
２０ａ：吸着剤カラム
Ｖ₁ ： 自動弁（オン−オフ弁）
Ｖ₂ ： 自動弁（オン−オフ弁）
Ｖ₃ ： 自動弁（オン−オフ弁）
Ｖ₄ ： 自動弁（オン−オフ弁）
Ｖ ： 真空ポンプ
Ｐ₁ ，Ｐ₂ ：圧力センサー
△Ｐ：吸着剤カラム層の上−下（入−出）端部差圧
【００３２】
実験操作例を以下に示す。そして、Ｖ₁ を所定時間開放した時の△Ｐの時間的変化を測定した結果を図４（Ａ）、（Ｂ）、（Ｃ）に示す。
吸着剤（２０ａ）は予め加熱・真空引などの手段で活性化しておく（Ｐ₁ −Ｐ₂ ＝一定）。
１．Ｖ₁ を０．１秒（１つの例）開放し、△Ｐの時間的変化を測定した結果を図４（Ａ）に示す。
２．Ｖ₁ を０．２秒開放し、△Ｐの時間的変化を測定した結果を図４（Ｂ）に示す。
３．Ｖ₁ を０．３秒開放し、△Ｐの時間的変化を測定した結果を図４（Ｃ）に示す。
【００３３】
図４（Ａ）、（Ｂ）、（Ｃ）を比較すると、山型頂部の形状が最初鋭角であったのが次第に円みを帯びた形へと変化する。（Ｃ）の場合、Ｖ₁ の開放により吸着塔（２０）へ流入した一定量のガス塊が吸着剤カラム２０ａの層を圧力波として円滑に伝播していることが判る。（Ｃ−１）は好適なパルス波を示す。また相当する量が最小最適なガス塊の量を示す。
Ｖ₁ を０．３秒開放した（第１回）時の（Ｃ−１）を第１パルスと称し、Ｖ₁を０．３秒開放した（第２回）時の（Ｃ−２）を第２パルスという。
Ｔ_C は第１パルス−第２パルス間にとられるべき時間間隙で、（Ｔ_C −０．３）（秒）を第１ポーズ（Ｚ₁ ）という。以下同様。
【００３４】
図４（Ａ）、（Ｂ）、（Ｃ）に示す波高（Ｈ_A 、Ｈ_B 、Ｈ_C ）、半波長（Ｔ_A、Ｔ_B 、Ｔ_C ）などは下記のような吸着システム構成要件や実験条件により決まる。
自動弁仕様
吸着塔仕様、内部構造
吸着剤：種別、粒度、活性化条件など
吸着剤カラム：断面積、層高
実験に用いるガス
自動弁Ｖ₃ が大気に開放されているか（Ｐ₁ ＞＞大気圧）
自動弁Ｖ₄ が開放され、ポンプＶで真空吸引されているか（Ｐ₁ ：大気圧近 傍）など
【００３５】
図５は、ＰＳＡ個別操作における典型的な弁シーケンス（弁の開放時間−時間の関係）例を示す。
図５の３０Ａ、３０Ｂ、３０Ｃの斜線部は弁が開放された状態を示す。
△ｔ₁ 、△ｔ₂ は、それぞれ第１パルス、第２パルスを示す。
△Ｚ₁ 、△Ｚ₂ は、それぞれ第１ポーズ、第２ポーズを示す。
図５は自動弁の上流−下流の圧力差が次第に減少する場合を示す（高速ＰＳＡに見られる例）。圧力差の減少とともにパルス幅（△ｔ_i ）が増大するが△ｔ_iに対応する量（Ｖｉ）は略一定に保たれる。
【００３６】
パルスの流量は前記式（２）（実験式）で示される。
以上をまとめると次のようになる。
ＰＳＡ個別操作において吸着塔に接続される自動弁（オン−オフ弁）の上流−下流差圧が変化するとき、同一量のガス塊を継続的に送りたい場合（”定流量制御”）は、
１．△Ｐ一定のときは、パルス幅（△ｔi ）は一定にすればよく、
２．△Ｐが減少するときは、パルス幅（△ｔi ）は増大させればよく、
３．△Ｐが上昇するときは、パルス幅（△ｔi ）は減少させればよい。
パージ操作は一般に自動弁上流−下流差圧が略一定の条件で行われるので、このときは弁シーケンスは例えば
１秒開−２秒停止−１秒開−２秒停止
のごとく行われ、一定量のガス塊が断続的に吸着塔へ送入される。
以上、自動弁上流−下流差圧が種々変動する条件下で“定速制御”できることを示した。
【００３７】
次に“パルス・パージ”操作を例にとって“定量（供給）制御”を行う例を示す。
“パージ”操作においては、前記式（１）（実験式）が成立する。
空気より酸素を分離する例（ＭＳ−５Ａ使用）ではα≒１であった。
各パルスの量Ｖ₁ 、Ｖ₂ …は同じ（Ｖ₀ とする）であった。また必要なパルス数ｎ＝Ｖ／Ｖ₀ ＝１〜３となった。
最大、最適なパージ供与速度は次式（３）となる。
【００３８】
【数５】

【００３９】
小型の吸着塔を用いた実験では、△ｔｉ＝０．１秒以下、△Ｚｉ＝０．４秒以下が可能であった。大型機の場合は小型機の１０〜２０倍となった。
【００４０】
【作用】
１）近年、ＰＳＡ法によるガス分離性能向上のためには自動弁を介して吸着塔へ出入するガス流れの迅速・精密制御法が必須の技術として期待されてきた。
２）ＰＳＡ法の循環操作は高速化に伴い、圧力変動が激しくなった。従来、秒単位で精密に流れを制御することは困難もしくは不可能であったが、本発明の簡単な方法ですべて解決された。
３）本発明の方法は市販・規格品または常用自動弁（オン−オフ弁）の精密な弁シーケンス（弁開放時間−時間関係）の設定のみでＰＳＡ全圧力変動過程の細部に亘り迅速・精密な制御を可能にした。
４）その結果、吸着剤の潜在性能を引き出し、ガス分離性能を格段に向上さす作用が生じた。
５）従来技術で不可能であった、短時間（秒単位）での“定速制御”や“定量供給制御”が可能となったので、
サイクルタイム短縮による、吸着剤生産性向上や
有用成分の損失防止による、製品収率の向上を図ることができた。
例えば、酸素濃縮装置の小型コンパクト、低コスト化及び省エネ向上に作用した。
６）本発明は酸素濃縮装置の性能向上のみならず、吸着塔と自動弁で構成されるあらゆるＰＳＡ装置の動作改善に作用するものである。
７）本発明は、従来装置に特別な部品や複雑な機構を付加するものでない。コストのかからないシーケンスの変更のみで、ＰＳＡ装置の省資材、省エネ性向上をもたらすものでその影響は広く、大きい。
８）本発明の方法は自動弁−吸着塔系に対するガス流の制御（ＰＳＡ）のみに限定されるものではない。自動弁−充填塔系に対しても有効である。後者のシステムに前記の操作を適用することにより、ガス流の安定化、定量化が可能となる。また充填塔に２系列のガス流をパルス波として交互に供給することにより、他端から所定混合比のガス流が得られる。これらの操作に必要なハードは弁と塔のみで化学工学上もっとも基本的かつ簡単な要素であって、目的に応じ、もっとも低価格、コンパクトな組み合わせを選択できる。そして単にシーケンスの変更で、種々の態様のガス流の迅速精密な制御が可能になるので、ガス処理に係わる化学装置の簡素化、低価格化およびその操作の改善などに大きく作用する。
【００４１】
【実施例】
以下に実施例をもって本発明を更に詳細に説明するが、本発明の主旨を逸脱しない限り、本発明は実施例に限定されるものではない。
（実施例１）
図１（ａ）は常用圧力スイング法の基本システム図（加圧法）であり、空気より酸素濃縮は本システムで実施されている。
図７は図１（ａ）のシステムを用いて本発明を実施するための標準弁シーケンス図である。図１（ａ）の構成については従来技術の欄で既に説明した。
本発明においては図１（ａ）の基本システムを用い、次の1)〜7)の７工程を順次経てガス分離が行われる。
塔１０ａに着目し、図７の弁シーケンスに従って操作を行う。
1)原料（ガス）加圧
2) 製品（ガス）取出し
3) パージ供与（パルス・パージ）
4)均圧−減圧
5)減圧
6)パージ（パルス・パージ）
7)均圧−加圧
以下、1)〜7)の７工程を繰り返す。
なお、この実施例１の工程は従来技術の説明で述べたものと全く同じであり、説明が重複するので省略する。3)、6)のパルス・パージ工程のみ従来技術と異なる（本発明における“パージ”は“パルス・パージ”と称す。以下同様）。
【００４２】
以下、従来技術の説明と同じく空気より酸素濃縮を例にとって“パルス・パージ”法を説明する。
3)パージ供与
2)の工程と同時もしくは少しおくれて、パージ弁３ａ（オン−オフ弁）の０．１秒開放−０．９秒閉止−０．１秒開放−０．９秒閉止の断続的開閉操作（パルス操作）を行う。
上例は１つの例であって、弁−吸着塔系シミュレーターで予め実験しておき、それによりパルス操作シーケンスが定められる。
製品Ｏ₂ の一部が、弁３ａを介して減圧下にある塔１０ｂの出口端部へ供給され、塔１０ｂ内を継続する２つの圧力波として塔１０ｂ内を向流方向に流れ、塔１０ｂの吸着剤カラムｂの吸着剤中に残留する不用ガス（Ｎ₂ ）をパージする。
【００４３】
6)パージ
塔１０ａの吸着剤カラムａ中に吸着されて残っている不用ガスの脱着は、製品ガスの一部を用いて行われる。即ち、パージ供給弁３ｂを０．１秒開−０．９秒閉−０．１秒開−０．９秒閉と操作し、塔１０ｂからの製品ガスを塔１０ａの出口端部へ断続的に供給し吸着剤カラム内に導入・流通させる。
導入された製品ガスは吸着剤カラム層ａ内を圧力波（正弦波）として伝播し、１つの伝播が終わったらすぐ次の第２波が供給される。
この製品ガスの圧力波は吸着剤カラム層ａ中に残留する不用ガス（Ｎ₂ ）の脱着に有効に作用し、弁５ａを経て、廃棄ライン１３を介して脱着された気体成分とともに放出される。
パルス数は小型機による酸素濃縮の場合、１〜３回で十分である。
またポーズ時間は小型機の場合、１秒以下で十分である。
【００４４】
（実施例２）
図２は、常用圧力スイング法の他の基本システム図（真空法）であり、空気より酸素濃縮は本システムで実施されている。
図８は、図２のシステムを用いて本発明を実施するための標準弁シーケンス図である。
図２の構成は次の１点を除いて、すなわち真空ポンプＶがついていることを除いて、図１と同じである。真空ポンプＶは減圧を促進するため（生産性向上、収率向上を目的とする）に設けられている。
塔１０ａに着目し、図２のシステムを用い、図８の弁シーケンスに従って次の1)〜7)の７工程を経てガス分離が行われる。
1)原料（ガス）加圧
2)製品（ガス）取出し
3)パージ供与（パルス・パージ）
4)均圧−減圧（パルス・均圧）
5)減圧・真空引
6)パージ（パルス・パージ）
7)均圧−加圧（パルス・均圧）
【００４５】
上記の1)〜7)の７つの工程は従来技術及び実施例１で説明したものと同じである。この実施例２はパルス・パージとパルス・均圧の２つの個別操作を用いた処に特長がある。
従来技術及び実施例１と説明が重復するのを避け“パルス・均圧”（4)と7)）のみについて以下に説明する。
【００４６】
図２のシステムを用い、図８の弁シーケンスに従って、空気より酸素濃縮を行う例について説明する。
4)均圧−減圧（パルス・均圧）
3)のパージ供与が終わったら、塔１０ａの加圧および塔１０ｂの減圧を停止する。直ちにパージ弁３ａ（均圧併用）と均圧弁４ａを同時に例えば、０．１秒開−０．４秒閉−０．５秒開の開閉操作を行い、加圧下の塔１０ａと減圧下の塔１０ｂとの上（出口）端部同志および下（入口）端部同志を連結して２つの塔の圧力平衡化を行う。
この際、一般に弁３ａ（３ｂ）と弁４ａ（４ｂ）は同一のサイズ仕様であって、上端部同志のガス移動量と下端部同志のガス移動量を同じくする。
【００４７】
7)均圧−加圧（パルス・均圧）
この工程は、減圧及び有用ガスパージを経て“再生”の終わった塔１０ａを再び循環使用に備えて圧力を復帰さすための前工程である。弁３ｂ−弁４ｂを同時に開放（同時に弁６、弁７開放）し、吸着塔１０ａ、吸着塔１０ｂを出口端部同志、入口端部同志を連結し、圧力平衡化を行う。吸着塔１０ａは圧力変動操作の略中間圧まで復圧し、1)の原料ガス加圧工程への準備をする。この後、弁１ａを開放する。
均圧のパルス数は小型機の場合１〜２で十分である。小型機および大型機について、自動弁（オン−オフ弁）、パルス時間（△ｔｉ）、ポーズ時間（△Ｚｉ）の好ましい態様を表１に示す。
【００４８】
【表１】

【００４９】
（実施例３）
図１に示す基本システム（装置）を使用し、実施例１に示す本発明に従うＰＡＳ法で空気より酸素を分離した。
吸着塔： 直径５．３ｃｍ、長さ２３ｃｍ（ステンレス製の筒）
吸着剤： ＭＳ−５Ａ、充填量 ４９８ｇ
吸着塔入口端部に活性アルミナを全層高の１５％迄充填した。使用した自動弁は電磁弁、ポンプはダイヤフラム式であった。
実施した弁シーケンスを表２に示す。
【００５０】
【表２】

【００５１】
以上の結果、純度９０％の濃縮酸素が毎分２リットルで連続的安定して得られた。
吸着剤生産性は２４０リットル（９０％Ｏ₂ ）／ｋｇ（Ｈ）であった。
より大きいポンプを接続しサイクルタイムを短縮したときは吸着剤生産性は３６０リットル（９０％Ｏ₂ ）／ｋｇ（Ｈ）であった。この値はさらに大きくすることが可能である。
従来技術では１００リットル（９０％Ｏ ₂ ）／ｋｇ（Ｈ）以下である。
【００５２】
【発明の効果】
１．本発明は最新ＰＳＡ法を特長づける“高速気体流れ”の迅速精密な制御法に係るものであり、本発明方法の適用によりＰＳＡ法全般の気体分離性能が大幅に改善された。
２．本発明のガス流制御方法は常用オン−オフ弁の精密シーケンス制御に係るものであり、従来技術のごとく特別な制御弁や弁機構は一切使用しないので、低コストで達成できる。
３．本発明の方法は弁−吸着塔間のガス流の制御を常用オン−オフ弁の一定のパターンに準拠した弁開閉操作（パルス的開閉操作）により行うものであり、どのような制御も単にシーケンス（パターン）を変更するだけでよいので、装置の改良・変更は必要なく、簡便な方法である。
４．本発明の方法は従来技術では不可能であった、自動弁上流−下流の差圧が秒単位で変動するプロセスの高速流れの精密な制御を可能とした。即ち、流れの平滑化、定速化、定量化が可能となった。
５．本発明の方法を空気より酸素濃縮分離に適用した場合、分離性能の著しい向上により酸素濃縮装置のコンパクト化（省資材化、低コスト化）、省エネ化が達成された。
６．本発明の方法は酸素分離のみならず、水素分離、炭酸ガス分離など広くＰＳＡ法全般の操作の改善に資するものである。
７．本発明の方法は化学工学のガスの流れを扱うプロセス、例えば定率供給（混合）、定量化、定速化など全般に適用可能であり、本法の採用により化学装置の簡単化、コンパクト化、省資材化、省エネ化が可能となり、化学工学操作全般の操作が改善されるので、本発明の効果は広範囲で大きい。
【図面の簡単な説明】
【図１】 （ａ）は、従来方法ならびに本発明の方法を実施するために利用される圧力・スイング法装置の基本システム例（２塔構成、加圧法）を示す説明図であり、（ｂ）は、（ａ）の基本システム例の変形態様を示す説明図である。
【図２】 従来方法ならびに本発明の方法を実施するための圧力スイング法装置の他の基本システム例（２塔構成、真空法）を示す説明図である。
【図３】 自動弁のパルス的開閉操作を示す実験システムを示す説明図である。
【図４】 （Ａ）はＶ₁ を例えば０．１秒開放した時の吸着塔の入口端部−出口端部間の差圧の時間的変化を示すグラフであり、（Ｂ）はＶ₁ を０．２秒開放した時の吸着塔の入口端部−出口端部間の差圧の時間的変化を示すグラフであり、（Ｃ）はＶ₁ を０．３秒開放した時の吸着塔の入口端部−出口端部間の差圧の時間的変化を示すグラフである。
【図５】 自動弁のパルス操作パターン例を示す説明図である。
【図６】 図１の基本システムを用いて従来の方法を実施するための１サイクルにおける弁の作動状態を示す説明図（弁シーケンス）である。
【図７】 図１のシステムを用いて本発明を実施するための標準弁シーケンス（加圧法）を示す説明図である。
【図８】 図２のシステムを用いて本発明を実施するための標準弁シーケンス（真空法）を示す説明図である。
【符号の説明】
ａ、ｂ 吸着剤カラム
Ｅ₁ 、Ｅ₂ 自動弁
Ｐ ポンプ
Ｖ 真空ポンプ
１ａ〜５ａ、１ｂ〜５ｂ、６、７、８ 自動弁
１０ａ、１０ｂ 吸着塔
１１ 気体混合物供給ライン
１２、１３ 廃棄ライン[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a pressure swing adsorption method and a pulse flow control method of a gas flow, and more specifically, a pulse flow control type pressure swing adsorption method for separating and extracting a required gas from a mixed gas as a raw material (PF-PSA,Gas separation by PSA)On the wayIt is related.
[0002]
[Prior art]
  1 (a) and 1 (b) show a PSA system diagram of a known two-column configuration in which unnecessary components in a raw material mixed gas are removed by adsorption and non-adsorbents are used as products.
  Figure6FIG. 2 is a diagram showing an operation state (referred to as a valve sequence) of each valve in one cycle when operating each valve of the system of FIG. 1A to perform a PSA method circulation operation. The hatched portion indicates that each valve is opened (the same applies hereinafter).
[0003]
  Hereinafter, the prior art will be described by taking as an example a case where oxygen is used as a product by adsorbing and separating unnecessary components (water, nitrogen, etc.) in the air as raw materials.
  FIG. 1A shows a basic system composed of two adsorption towers, but several modified systems are conceivable even when limited to a PSA system having two towers.
  FIG.1 (b) shows the example of the deformation | transformation system of Fig.1 (a).
  Figure2 isAn example of another basic system using two pumps (one for compression and one for vacuum citation) is shown.
[0004]
  Fig. 1 (a) (Basic hardware)6Although the prior art will be described with respect to (basic software corresponding to FIG. 1), the “pulse flow control operation” in the present invention is applicable to all these PSA systems and their operating software (valve sequence).
[0005]
  An example will be described in which oxygen is used as a raw material and oxygen (useful component) is produced by adsorbing and removing moisture and nitrogen components (unnecessary gas components) therein.
  In FIG. 1 (a), 10a and 10b are adsorption towers each containing adsorbent columns (layers) a and b, 1a to 5a, 1b to 5b, and 6 are electromagnetic valves that are opened and closed by electric force or air pressure, Automatic valves (on-off valves) such as motor valves, diaphragm valves, piston valves, butterfly valves (hereinafter referred to as automatic valves). 3a and 3b are purge valves, and 3a to 4a (3b to 4b) are simultaneously operated and used for pressure balancing (equal pressure) between the two columns (10a and 10b).
  P is a pump, 11 is a gas mixture supply source, and 12 and 13 are waste lines.
[0006]
  In the PSA method, the following seven steps are sequentially performed in accordance with the valve sequence shown in FIG. 7 in the two-column PSA system shown in FIG.
1 Raw material (gas) pressurization
2 Product (gas) removal
3 Purging
4 equal pressure-decompression
5 Depressurization
6 Purge
7 Pressure equalization / pressurization
  Thereafter, the steps 1 to 7 are repeated.The
[0007]
  In the above example, the example including the “equal pressure” operation is shown, but the simpler one sequentially goes through the following five steps not including the “equal pressure” operation. That is
1 Raw material gas pressurization
2 Product gas removal
3 Purging
4 Depressurization
5 Purge
  Thereafter, the above steps 1 to 5 are repeated.
[0008]
  When separating oxygen from air, the adsorbents in the adsorbent columns a and b are nitrogen selective adsorbents such as MS-5A, MS-13X, and LiX. In many cases, the adsorbent layer is composed of two layers, and a moisture adsorbent layer such as silica gel or activated alumina is provided at the inlet end for removing moisture in the air. The adsorbent is activated in advance by means such as heating or a combination of heating and vacuum drawing, and is filled with dry air or dry nitrogen and sealed. All the automatic valves in the system shown in FIG. The operation starts from this state.
  Next, FIG.6The valve sequence (automatic valve opening time to time relationship) will be described focusing on the tower 10a.
[0009]
1. Raw material pressurization
  The pump P is started, the valve 6 is closed, and the valve 1a is opened.
  The gas mixture (air or an industrially produced mixed gas) is sucked by the pump P from the gas mixture supply source 11, and continuously introduced into the adsorbent layer inlet end of the adsorption tower 10a through the valve 1a under pressure. Is done. By introducing the gas into the adsorption tower 10a, unnecessary gas components are adsorbed to the adsorbent of the adsorbent column a from the inlet side, and the adsorbent layer has an adsorbed gas zone (the concentration of unnecessary components in the adsorbent on the inlet side is large. The concentration decreases along the direction of flow), and with the introduction of the gas mixture, the tip of the zone advances along the adsorption tower.
[0010]
2. Product removal
  When the pressure in the adsorption tower reaches a predetermined pressure, the valve 2a is opened and the required gas component (O₂) Is taken out of the system through the valve 2a and the flow rate control valve (not shown).
[0011]
3. Purge provision
  The purge valve 3a is opened at the same time or slightly after the above step 2, and the product gas (O₂ ) Is under reduced pressure from the tower 10a through the valve 3a (Fig.6Reference) Supplied to the outlet end of the column 10b, flows in the counter 10b in the counter-current direction (the direction opposite to the raw material gas feed direction of the column 10b), and enters the adsorbent of the adsorbent column b of the column 10b. Residual waste gas (N₂ ).
  Waste gas (N₂ In order to improve the desorption effect of (), this purge operation is important and directly relates to the basic performance of the separation.
[0012]
4). Equal pressure reduction
  Valve 2a is closed, valves 3a and 4a are opened at the same time (valve 6 is opened, valve 5b is closed), tower 10a and tower 10b are connected at the outlet end, and inlet ends are connected at the same time. Equilibrate (equal pressure).
  This operation is performed prior to the countercurrent depressurization of the column 10a.₂ Rich gas) is collected.
  Control of gas flow in this operation is important, and directly related to the basic performance of the separation is the same as “purge”.
[0013]
5). Decompression (release)
  The valve 5a is opened, and a part of the unnecessary gas component remaining in the pressurized state in the adsorption tower 10a is discharged out of the system through the waste line 13. Although the gas phase portion gas in the adsorption tower 10a is almost removed by this releasing step, a considerable amount of unnecessary gas components still remain adsorbed inside the adsorbent of the adsorbent column a.
[0014]
6). purge
  Desorption of unused components remaining adsorbed in the adsorbent of the adsorption tower 10a is performed using a part of the product gas. That is, the purge supply valve 3b is opened, and a part of the product gas from the column 10b is introduced and circulated into the adsorbent column a from the outlet end of the column 10a in the direction opposite to the flow direction of the raw material gas mixture.
  The introduced product gas desorbs the adsorbed unnecessary gas components, and is discharged together with the desorbed gas components via the disposal line 13 via the valve 5a. The above desorption procedure for desorbing the adsorbed gas component using the product gas is called “purge method”. Since the gas used for purging is a product gas and is lost in the above operation, it is required to increase the desorption effect as quickly as possible and in the smallest possible amount. Therefore, the adjustment of the gas flow during the “purge” operation is directly related to the basic performance of the separation.
[0015]
7). Pressure equalization / pressurization
  The valve 3b and the valve 4b are simultaneously opened (the valve 6 is simultaneously opened), and the outlet towers of the adsorption tower 10a and the adsorption tower 10b are connected to each other to perform pressure equilibrium. The valuable gas in the adsorption tower 10b is transferred into the adsorption tower 10a, and the pressure in the adsorption tower 10a is restored to the intermediate pressure of the operation. Prepare for the raw material pressing step.
  Thereafter, the valve 1a is opened, and the above seven steps 1 to 7 are repeated.
[0016]
  The seven steps 1 to 7 are referred to as one cycle step (T, second).
  The gas separation operation for the adsorption tower 10a comprising the above seven steps is similarly performed for the adsorption tower 10b.
  However, figure6As shown in FIG. 4, the steps 1 to 4 of the adsorption tower 10a (or 10b) and the steps 5 to 7 of the adsorption tower 10b (or 10a) are performed at a time of T / 2 hours so as to proceed at the same time.
  The steps 1 to 4 are a pressurizing step or a product take-out step, and the steps 5 to 7 can be summarized as a depressurizing step or a regeneration step.
[0017]
  As described above, the gas separation operation of the adsorption tower 10a and the gas separation operation of the adsorption tower 10b are repeated in order to produce a desired gas demand.
  In this way, the product gas is alternately sent from each column 10a, 10b to a product reservoir (not shown) and is continuously supplied from there to the consumption end.
[0018]
  In the above, the PSA including two individual operations of “purge” and “pressure equalization” has been described for the most basic two-column configuration system of the prior art.
  FIG.1 (b) is a deformation | transformation aspect of Fig.1 (a). E₁ , E₂ Is a pressure equalizing valve, and operates in the steps 4 and 7.
[0019]
  Even if the PSA system is limited to the most basic two-column system, there are several variations. For example, there are two ways of using a single pump (two ways: a method using only a pressurizing pump and a method using a combined pressure-vacuum pump)
  Figure2 isThe method using two pumps is shown.
  Although only the most basic two-column system is shown, the PSA system can be modified in many other configurations by changing the number of towers and the number of pumps.
  The PSA operation consists of a combination of several individual operations (steps). In the above description of the prior art, a typical separation method including two individual operations of “purge” and “pressure equalization” has been described. In addition, the operations may include individual operations such as “product pressurization”, “recycling”, and “gas phase replacement” (performed when the adsorbed component is a product).
[0020]
[Problems to be solved by the invention]
  The improvement direction of gas separation by the PSA method is summarized in the following two points.
1. Increase adsorbent productivity. That is, product gas m^Three Increase (STP) / kg adsorbent (H). In this way, the device is compact and saves material, and the device price is reduced.
2. Decrease in power consumption rate. That is, KWH / product gas m^Three (STP) is reduced. This increases the yield when the pressure operating conditions (applied electric energy) are constant.
  Although the prior art has been improved for many years, there is a strong and constant demand for improvement in light of the above improvement direction. In particular, when oxygen is separated from air as a product, the use of oxygen in the environment and energy fields is expected to increase in recent years and the amount of use is expected to increase.
[0021]
  In order to increase adsorbent productivity, it is generally necessary to shorten the cycle time or increase the number of cycles per hour while maintaining the product delivery rate per cycle. Is to connect a larger pump to the adsorption tower (or to reduce the volume of the adsorption tower with respect to one pump), and the speed of pressurization and depressurization of the adsorption tower is increased.
  For this reason, for each adsorbent in each individual operation of PSA,
  a. Gas rushing impact occurs,
  b. Drifting,
  c. The linear velocity and space velocity will increase significantly compared to the conventional standards,
Also for the pump,
  d. Switching between the individual operations (steps) constituting the cycle is rapid, and a pressure shock may occur.
  As a result, the gas component distribution in the gas phase and solid phase of the adsorbent column is disturbed, the pump malfunctions, and the product with the desired purity cannot be stably obtained, reducing the adsorbent productivity and product yield. Cause.
[0022]
  The above problems can be solved by controlling the gas movement quickly and precisely in consideration of the following 1 to 3 when performing individual operations of the PSA.
  1. The adsorption zone should not be disturbed or spread even if the adsorption tower flow speed is increased.
  2. For operations involving the loss of valuable gas components such as “purge”, the amount of valuable gas transferred must be small.
  3. When switching between steps of individual operation and individual operation, the switching operation should be smooth so as not to cause pressure fluctuations protruding in the switching tower or pump line.
[0023]
  Conventional gas flow control means have been carried out using the following 1-4.
  1. Used in conjunction with the orifice-automatic valve (on-off valve) and check valve.
  2. There are many flow control valves-diaphragm valves.
  3. Feedback control of a sensor to an automatic valve system is performed, and a pressure, temperature sensor, or the like is used as the sensor.
  4). A reservoir is used for buffering the pressure fluctuation between steps, and there are two types of reservoirs, a constant capacity tank and a variable capacity tank.
[0024]
  However, the gas flow control means in the above prior art has the following problems 1 to 4.
  1. Orifice is accompanied by energy loss. There is little flow and control is not enough.
  2. Flow control valves are slow in response and expensive.
  3. Feedback control is the most complex and expensive and is usually used in one individual operation such as “equal pressure equalization”. Further, this control is mainly pressure and temperature control, and fine flow rate control is not possible.
  4). It cannot be made compact and the cost is high.
[0025]
[Means for Solving the Problems]
  The above problems in the prior art are all solved by precision sequence operation of an automatic valve (on-off valve). The only necessary hardware in the present invention is an on-off valve.
  The invention of claim 1 of the present inventionPressure swing adsorption with two or more adsorption towers, one or more pumps, multiple automatic valves (on-off valves) ( Pressure Swing Adsorption , PSA) is a pressure swing adsorption method (PSA method) using non-adsorbed components and / or adsorbed components as a product, and in one circulation operation of the PSA, supply of raw material gas, pressurization of product gas, discharge under reduced pressure In addition to the basic individual operations of 1) ~ Five) At least one PSA individual operation (step) selected from the above, the step change in the apparatus depends on a certain pattern of automatic valve opening / closing operation including one or more instantaneous (pulse-like) opening / closing, An automatic valve (on-off valve) that performs a gas transfer test by setting the simulator to the conditions before the step change (adsorption tower, differential pressure between the upstream and downstream of the automatic valve, etc.) by the simulator (adsorption tower-automatic valve system) ) Was measured as a parameter, and the time variation of the differential pressure in the adsorbent column (Δp, differential pressure between the inlet end and the outlet end) corresponding to Δti was measured. The axis and the elapsed time (t) are taken as a horizontal axis. When this figure shows a sine wave (half wavelength) or an approximate form thereof, Δti is a pulse time, and the gas movement amount corresponding to Δti is Vi. Half wavelength of sine wave When the △ ti the value obtained by subtracting the △ Zi from between, △ t ₁ -△ Z ₁ -△ t ₂ -△ Z ₂ .... The amount of gas movement (ΣVi) and gas movement speed (ΣVi / Σ (Δti + ΔZi)) required for the individual operations described above by the valve sequence of △ ti- △ Zi (valve opening time-time relationship) Controlled, pressure fluctuation in step change, and improved gas separation effect, pulse flow control pressure swing adsorption method ( Pulsed Flow Controlled Pressure Swing Adsorption, PF-PSA )It is.
  1) Purging with valuable gas (Purge)
  2) Pressure equilibration between two towers (equal pressure)
  3) Re-pressurization with product gas (product pressurization)
  4) Collection (recycling) of valuable gas through the pump
  5) Substitution of gas phase gas in the tower with adsorbed component gas (gas phase substitution)
0026]
  The invention of claim 2 of the present invention is claimed in claim1In the above-described pulse flow control type pressure swing adsorption method, the purge operation is performed based on the following equation (1).
0027]
[Equation 3]

0028]
  The invention of claim 3 of the present invention is claimed in claim1Or claims2In the above-described pulse flow control type pressure swing adsorption method, the gas amount (Vi) passing through the automatic valve is determined by the following equation (2).
0029]
[Expression 4]

0030]
  The invention of claim 4 of the present invention is the claim of claim1Or claimsWrite in any of 3In the pulse flow control type pressure swing adsorption methodThe pulse time Δti and the pause time ΔZi according to claim 1 are in the following ranges.
  Solenoid valve: Δti; 0.05 to 1.0 seconds
          ΔZi: 0.1 to 2.0 seconds
  Pneumatically operated valve:
          Δti: 0.5 to 3.0 seconds
          ΔZi: 1.0 to 6.0 seconds
0031]
DETAILED DESCRIPTION OF THE INVENTION
  First figure3The behavior of the gas flowing into and out of the adsorption tower 20 was examined using the experimental apparatus shown in FIG.
    20: Adsorption tower
    20a: adsorbent column
    V₁ : Automatic valve (on-off valve)
    V₂ : Automatic valve (on-off valve)
    V_Three : Automatic valve (on-off valve)
    V_Four : Automatic valve (on-off valve)
    V: Vacuum pump
    P₁ , P₂ :pressure sensor
    ΔP: Upper-lower (in / out) end differential pressure of adsorbent column layer
0032]
  An example of the experimental operation is shown below. And V₁ Figure shows the results of measuring the change in ΔP over time when4Shown in (A), (B), (C).
  The adsorbent (20a) is activated in advance by means such as heating and vacuuming (P₁ -P₂ = Constant).
  1. V₁ Is opened for 0.1 second (one example), and the time-dependent change of ΔP is measured.4Shown in (A).
  2. V₁ Fig. 2 shows the result of measuring the change in ΔP over time by opening4Shown in (B).
  3. V₁ Fig. 3 shows the result of measuring the change in ΔP over 0.3 seconds.4Shown in (C).
0033]
  Figure4Comparing (A), (B), and (C), the shape of the top of the mountain-shaped peak is gradually changed to a rounded shape from the initial acute angle. For (C), V₁ It can be seen that a certain amount of gas mass flowing into the adsorption tower (20) due to the opening of the gas is smoothly propagated as a pressure wave through the layer of the adsorbent column 20a. (C-1) shows a suitable pulse wave. The corresponding amount indicates the minimum amount of gas mass.
  V₁ (C-1) at the time of opening for 0.3 seconds (first time) is called the first pulse, and V₁(C-2) when the above is opened for 0.3 seconds (second time) is referred to as a second pulse.
  T_C Is the time gap to be taken between the first and second pulses, (T_C -0.3) (seconds) to the first pose (Z₁ ). The same applies below.
0034]
  Figure4Wave height (H) shown in (A), (B), (C)_A , H_B , H_C ), Half wavelength (T_A, T_B , T_C ) Etc. are determined by the following adsorption system configuration requirements and experimental conditions.
    Automatic valve specifications
    Adsorption tower specifications, internal structure
    Adsorbent: Type, particle size, activation conditions, etc.
    Adsorbent column: sectional area, bed height
    Gas used for experiment
    Automatic valve V_Three Is open to the atmosphere (P₁ >> Atmospheric pressure)
    Automatic valve V_Four Is open and vacuumed by pump V (P₁ : Near atmospheric pressure)
0035]
  Figure5Shows an example of a typical valve sequence (valve opening time-time relationship) in PSA individual operation.
  Figure5The shaded portions of 30A, 30B, and 30C indicate a state in which the valve is opened.
  △ t₁ , △ t₂ Indicates a first pulse and a second pulse, respectively.
  △ Z₁ , △ Z₂ Indicates a first pose and a second pose, respectively.
  Figure5Shows the case where the pressure difference between the upstream and downstream of the automatic valve gradually decreases (example seen in high-speed PSA). As the pressure difference decreases, the pulse width (Δt_i ) Increases but Δt_iThe amount (Vi) corresponding to is kept substantially constant.
0036]
  The flow rate of the pulse is expressed by the above formula (2) (empirical formula).
  The above is summarized as follows.
  When the upstream-downstream differential pressure of the automatic valve (on-off valve) connected to the adsorption tower in the individual operation of PSA changes, if you want to send the same amount of gas mass continuously ("constant flow control"),
  1. When ΔP is constant, the pulse width (Δti) may be constant.
  2. When ΔP decreases, the pulse width (Δti) may be increased,
  3. When ΔP increases, the pulse width (Δti) may be decreased.
  Since the purge operation is generally performed under the condition that the automatic valve upstream-downstream differential pressure is substantially constant, the valve sequence is, for example,
    1 second open-2 seconds stop-1 second open-2 seconds stop
A certain amount of gas mass is intermittently sent to the adsorption tower.
  As described above, it has been shown that “constant speed control” can be performed under conditions in which the differential pressure upstream and downstream of the automatic valve varies.
0037]
  Next, an example in which “quantitative (supply) control” is performed by taking “pulse purge” operation as an example.
  In the “purge” operation, the above equation (1) (empirical equation) is established.
  In an example in which oxygen was separated from air (using MS-5A), α≈1.
  The amount of each pulse V₁ , V₂ ... is the same (V₀ And). Necessary number of pulses n = V / V₀ = 1-3.
  The maximum and optimum purge supply rate is expressed by the following equation (3).
0038]
[Equation 5]

0039]
  In an experiment using a small adsorption tower, Δti = 0.1 seconds or less and ΔZi = 0.4 seconds or less were possible. In the case of a large machine, it was 10 to 20 times that of a small machine.
0040]
[Action]
1) In recent years, in order to improve the gas separation performance by the PSA method, a rapid and precise control method of the gas flow entering and exiting the adsorption tower via an automatic valve has been expected as an essential technology.
2) The pressure fluctuation in the circulation operation of the PSA method became severe as the speed increased. Conventionally, it has been difficult or impossible to precisely control the flow in units of seconds, but all have been solved by the simple method of the present invention.
3) The method of the present invention can be performed quickly and precisely over the details of the PSA total pressure fluctuation process only by setting a precise valve sequence (valve opening time-time relationship) of a commercially available standard product or a regular automatic valve (on-off valve). Control was possible.
4) As a result, the action of drawing out the potential performance of the adsorbent and remarkably improving the gas separation performance occurred.
5) “Constant speed control” and “Quantitative supply control” in a short time (seconds), which was impossible with the conventional technology, became possible.
  Improved adsorbent productivity by shortening cycle time
  The product yield could be improved by preventing the loss of useful components.
  For example, the oxygen concentrator was compact, compact, low cost and improved energy saving.
6) The present invention not only improves the performance of the oxygen concentrator, but also improves the operation of all PSA devices composed of adsorption towers and automatic valves.
7) The present invention does not add any special parts or complicated mechanisms to the conventional apparatus. Only the change of the sequence that does not cost costs brings about the material saving and the energy saving improvement of the PSA apparatus, and its influence is wide and large.
8) The method of the present invention is not limited to gas flow control (PSA) only for automatic valve-adsorption tower systems. It is also effective for automatic valve-packed tower systems. By applying the above operation to the latter system, the gas flow can be stabilized and quantified. In addition, by alternately supplying two series of gas flows as pulse waves to the packed tower, a gas flow having a predetermined mixing ratio can be obtained from the other end. The hardware necessary for these operations is only a valve and a tower, and it is the most basic and simple element in chemical engineering. Depending on the purpose, the most inexpensive and compact combination can be selected. Further, by simply changing the sequence, it becomes possible to quickly and precisely control the gas flow in various modes, which greatly affects the simplification, cost reduction, and improvement of the operation of the chemical apparatus for gas processing.
0041]
【Example】
  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the examples without departing from the gist of the present invention.
Example 1
  FIG. 1A is a basic system diagram (pressurization method) of the normal pressure swing method, and oxygen concentration from air is performed in this system.
  Figure7FIG. 2 is a standard valve sequence diagram for carrying out the present invention using the system of FIG. The configuration of FIG. 1A has already been described in the section of the prior art.
  In the present invention, the basic system shown in FIG. 1A is used, and gas separation is performed through the following seven steps 1) to 7) in sequence.
  Pay attention to the tower 10a,7Operate according to the valve sequence.
1) Raw material (gas) pressurization
2) Product (gas) removal
3) Purge supply (pulse purge)
4) Pressure equalization-decompression
5) Depressurization
6) Purge (pulse purge)
7) Pressure equalization-pressurization
  Thereafter, the seven steps 1) to 7) are repeated.
  Note that the steps of the first embodiment are exactly the same as those described in the description of the prior art, and a description thereof is omitted because it is redundant.3), 6) is different from the prior art only in the pulse / purge process (“Purge” in the present invention is referred to as “pulse purge”, and so on).
0042]
  Hereinafter, the “pulse purge” method will be described by taking oxygen concentration as an example from the air as in the description of the prior art.
3) Purging
  Simultaneously or slightly after the step 2), the purge valve 3a (on-off valve) is opened for 0.1 seconds-0.9 seconds closed-0.1 seconds opened-0.9 seconds closedContinuedOpen / close operation (pulse operation).
  The above example is one example, and a pulse operation sequence is determined by conducting an experiment in advance using a valve-adsorption tower system simulator.
  Product O₂ Is supplied to the outlet end of the tower 10b under reduced pressure through the valve 3a and flows in the counter-current direction in the tower 10b as two pressure waves that continue in the tower 10b. Waste gas remaining in the adsorbent of column b (N₂ )The
0043]
6) Purge
  Desorption of the unnecessary gas remaining in the adsorbent column a of the tower 10a is performed using a part of the product gas. That is, the purge supply valve 3b is operated as 0.1 second open-0.9 second closed-0.1 second open-0.9 second closed, and the product gas from the tower 10b is intermittently supplied to the outlet end of the tower 10a. To be introduced into and distributed in the adsorbent column.
  The introduced product gas propagates as a pressure wave (sine wave) in the adsorbent column layer a, and the next second wave is supplied as soon as one propagation is finished.
  The pressure wave of this product gas is a waste gas remaining in the adsorbent column layer a (N₂ ), And is released together with the gaseous component desorbed via the waste line 13 via the valve 5a.
  In the case of oxygen concentration using a small machine, 1 to 3 pulses are sufficient.
  In the case of a small aircraft, a pause time of 1 second or less is sufficient.
0044]
(Example 2)
  FIG. 2 is another basic system diagram (vacuum method) of the normal pressure swing method, in which oxygen enrichment is performed by this system.
  Figure8These are the standard valve sequence diagrams for implementing this invention using the system of FIG.
  The configuration of FIG. 2 is the same as that of FIG. 1 except for the following one point, that is, the vacuum pump V is attached. The vacuum pump V is provided to promote pressure reduction (for the purpose of improving productivity and yield).
  Focusing on the tower 10a, using the system of FIG.8Gas separation is carried out through the following seven steps 1) to 7) according to the valve sequence.
  1) Raw material (gas) pressurization
  2) Product (gas) removal
  3) Purge supply (pulse purge)
  4) Pressure equalization-pressure reduction (pulse, pressure equalization)
  5) Depressurization / evacuation
  6) Purge (pulse purge)
  7) Pressure equalization-pressurization (pulse / equal pressure)
0045]
  The above seven steps 1) to 7) are the same as those described in the prior art and Example 1. The second embodiment is characterized by a process using two individual operations of pulse purge and pulse pressure equalization.
  Only the “pulse and pressure equalization” (4) and 7)) will be described below to avoid duplication of the description of the prior art and the first embodiment.
0046]
  Using the system of FIG.8An example of performing oxygen concentration from air according to the valve sequence will be described.
4) Pressure equalization-pressure reduction (pulse, pressure equalization)
  When the provision of the purge in 3) is finished, the pressurization of the column 10a and the depressurization of the column 10b are stopped. Immediately, the purge valve 3a (equal to pressure equalization) and the pressure equalization valve 4a are simultaneously opened and closed, for example, 0.1 second open-0.4 second closed-0.5 second open, and the pressurized column 10a and the reduced pressure column The upper (exit) end comrades and the lower (inlet) end comrades with 10b are connected for pressure equilibration of the two columns.
  In this case, generally, the valve 3a (3b) and the valve 4a (4b) have the same size specification, and the gas movement amount between the upper end portions and the gas movement amount between the lower end portions are the same.
0047]
7) Pressure equalization-pressurization (pulse / equal pressure)
  This step is a pre-step for returning the pressure so that the tower 10a, which has been "regenerated" through pressure reduction and useful gas purging, is again ready for circulation. The valves 3b and 4b are simultaneously opened (the valves 6 and 7 are simultaneously opened), the adsorption tower 10a and the adsorption tower 10b are connected to each other at the outlet end, and the inlet ends are connected to perform pressure balancing. The adsorption tower 10a returns the pressure to approximately the intermediate pressure of the pressure fluctuation operation, and prepares for the source gas pressurizing step 1). Thereafter, the valve 1a is opened.
  In the case of a small machine, 1 to 2 is sufficient for the number of equalizing pulses. Table 1 shows preferable modes of the automatic valve (on-off valve), the pulse time (Δti), and the pause time (ΔZi) for the small machine and the large machine.
0048]
[Table 1]

0049]
(Example 3)
  Using the basic system (apparatus) shown in FIG. 1, oxygen was separated from air by the PAS method according to the present invention shown in Example 1.
  Adsorption tower: Diameter 5.3cm, length 23cm (stainless steel cylinder)
  Adsorbent: MS-5A, filling amount 498g
  At the inlet end of the adsorption tower, activated alumina was filled up to 15% of the total layer height. The automatic valve used was a solenoid valve, and the pump was a diaphragm type.
  The implemented valve sequence is shown in Table 2.
0050]
[Table 2]

0051]
  As a result of the above, concentrated oxygen with a purity of 90% per minute2It was obtained in a continuous and stable manner with a kettle.
  Adsorbent productivity is240Liters (90% O₂ ) / Kg (H).
  When a larger pump is connected and the cycle time is shortened, the adsorbent productivity is360Liters (90% O₂ ) / Kg (H). This value can be further increased.
  In the prior art, 100 liters (90% O ₂ ) / Kg (H) or less.
0052]
【The invention's effect】
1. The present invention relates to a rapid and precise control method of “high-speed gas flow” that characterizes the latest PSA method. By applying the method of the present invention, the gas separation performance of the PSA method as a whole has been greatly improved.
2. The gas flow control method according to the present invention relates to precise sequence control of a regular on-off valve, and does not use any special control valve or valve mechanism as in the prior art, and can be achieved at low cost.
3. In the method of the present invention, the gas flow between the valve and the adsorption tower is controlled by a valve opening / closing operation (pulsed opening / closing operation) in accordance with a regular pattern of the regular on-off valve, and any control is simply a sequence. Since only the (pattern) needs to be changed, there is no need to improve or change the apparatus, and this is a simple method.
4). The method of the present invention enables precise control of the high-speed flow of a process in which the differential pressure between the upstream and downstream of the automatic valve fluctuates in seconds, which was not possible with the prior art. That is, smoothing, constant speed, and quantification of the flow became possible.
5). When the method of the present invention is applied to oxygen concentration / separation from air, the oxygen concentrator can be made compact (material saving and cost reduction) and energy saving can be achieved due to the remarkable improvement in separation performance.
6). The method of the present invention contributes not only to oxygen separation but also to improvement of the overall operation of the PSA method, such as hydrogen separation and carbon dioxide separation.
7). The method of the present invention can be applied to processes that deal with gas flow in chemical engineering, for example, constant rate supply (mixing), quantification, constant speed, etc. By adopting this method, the chemical apparatus can be simplified, made compact, Since material saving and energy saving are possible and the overall operation of chemical engineering operation is improved, the effects of the present invention are large and large.
[Brief description of the drawings]
FIG. 1 (a) is an explanatory diagram showing a basic system example (two-column configuration, pressurization method) of a pressure / swing method apparatus used for carrying out the conventional method and the method of the present invention; () Is an explanatory view showing a modification of the basic system example of (a).
FIG. 2 is an explanatory view showing another basic system example (two-column configuration, vacuum method) of a conventional method and a pressure swing method apparatus for carrying out the method of the present invention.
[Figure3An explanatory diagram showing an experimental system showing a pulsed opening / closing operation of an automatic valve.
[Figure4] (A) is V₁ Is a graph showing the change over time in the pressure difference between the inlet end and the outlet end of the adsorption tower when, for example, 0.1 second is opened, (B) is V₁ It is a graph which shows the time change of the differential pressure | voltage between the inlet-end part of an adsorption tower, and an outlet-end part when 0.2 second is open | released, (C) is V₁ It is a graph which shows the time change of the differential pressure between the inlet-end part of an adsorption tower, and an outlet-end part when open | releases for 0.3 second.
[Figure5An explanatory view showing an example of a pulse operation pattern of an automatic valve.
[Figure6FIG. 11 is an explanatory diagram (valve sequence) showing the operating state of a valve in one cycle for carrying out the conventional method using the basic system of FIG. 1;
[Figure7FIG. 2 is an explanatory view showing a standard valve sequence (pressure method) for carrying out the present invention using the system of FIG. 1;
[Figure8FIG. 3 is an explanatory diagram showing a standard valve sequence (vacuum method) for carrying out the present invention using the system of FIG.
[Explanation of symbols]
  a, b Adsorbent column
  E₁ , E₂   Automatic valve
  P pump
  V Vacuum pump
  1a-5a, 1b-5b, 6, 7, 8 Automatic valve
  10a, 10b adsorption tower
  11 Gas mixture supply line
  12, 13 Waste line

Claims (4)

Pressure swing using non-adsorbed components and / or adsorbed components as a product by pressure swing adsorption ( PSA) equipment equipped with two or more adsorption towers, one or more pumps, and a plurality of automatic valves (on-off valves) Adsorption method (PSA method), and at least one selected from the following 1) to 5) in addition to the basic individual operations of feed gas supply pressurization, product gas delivery and decompression discharge within one circulation operation of the PSA The switching of the steps in the apparatus depends on a certain pattern of automatic valve opening / closing operation including one or more instantaneous (pulse-like) opening / closing, and the determination of the pattern is performed by a simulator (adsorption tower- Automatic valve system (on-off valve) that sets the simulator to the conditions before the step change (adsorption tower, automatic valve differential pressure between upstream and downstream, etc.) and conducts gas transfer test The time variation of the differential pressure in the adsorbent column (Δp, differential pressure between the inlet end and the outlet end) corresponding to Δti is measured using Δt as the parameter, and Δp is the vertical axis. , Where the elapsed time (t) is a horizontal axis, Δti is a sine wave (half wavelength) or an approximate form thereof, Δti is a pulse time, the gas movement amount corresponding to Δti is Vi, and the sine When the value obtained by subtracting Δti from the half-wave time of the wave is ΔZi, Δt ₁ -△ Z ₁ -△ t ₂ -△ Z ₂ .... The amount of gas movement (ΣVi) and gas movement speed (ΣVi / Σ (Δti + ΔZi)) required for the individual operations are determined by the valve sequence of △ ti- △ Zi (valve opening time-time relationship). Pulsed Flow Controlled Pressure Swing Adsorption (PF-PSA ) , characterized by controlling and smoothing pressure fluctuation in step change and improving gas separation effect .
1) Purging with valuable gas (Purge)
2) Pressure equilibration between two towers (equal pressure)
3) Re-pressurization with product gas (product pressurization)
4) Collection (recycling) of valuable gas through the pump
5) Substitution of gas phase gas in the tower with adsorbed component gas (gas phase substitution) Following formula purging pulsed flow control type pressure swing adsorption process of claim 1 Symbol placement and performing based on (1).

Amount of gas passing through the automatic valve pulsed flow control type pressure swing adsorption process of claim 1 or claim 2 Symbol mounting, characterized in that the determined by (Vi) the following equation (2).

The pulse time Δti and the pause time ΔZi according to claim 1 are in the following ranges. The pulse flow control type pressure swing adsorption method according to any one of claims 1 to 3.
Solenoid valve: Δti; 0.05 to 1.0 seconds
ΔZi: 0.1 to 2.0 seconds
Pneumatically operated valve:
Δti: 0.5 to 3.0 seconds
ΔZi: 1.0 to 6.0 seconds

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