JPH0456648B2

JPH0456648B2 -

Info

Publication number: JPH0456648B2
Application number: JP61142854A
Authority: JP
Inventors: Tadayoshi Tomita; Takayuki Sakamoto; Toshihiro Ishida; Atsushi Morya; Umetaro Ookamo; Takeji Yoneyama; Giichi Noguchi
Original assignee: Jushitsuyu Taisaku Gijutsu Kenkyu Kumiai
Current assignee: Jushitsuyu Taisaku Gijutsu Kenkyu Kumiai
Priority date: 1986-06-20
Filing date: 1986-06-20
Publication date: 1992-09-09
Also published as: JPS631416A

Description

【発明の詳細な説明】［産業上の利用分野］本発明は原料ガスを吸着によつて精製するブレ
ツシヤスイング吸着法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a breather swing adsorption method for purifying raw material gas by adsorption.

［従来の技術］従来、原料ガス中の除去成分を選択的に吸着除
去するガスの精製法としてプレツシヤスイング吸
着法がある。この方法は次のような工程、すなわ
ち、 (a) 高圧の原料ガスを吸着床を通過させ、吸着床
がほぼ飽和に達したら、 (b) 工程(a)のガス流入方向と並流に減圧し、流出
ガスは工程(e)にある吸着床に、両者の圧力がほ
ぼ平衡するまで流入させ、 (c) さらに並流に減圧して、流出したガスはパー
ジガスとして工程(d)にある吸着床に流入させ、 (d) 最低圧力までさらに向流に減圧して、パージ
ガスによる脱着を併用して吸着床を脱着させ、 (e) 工程(b)からの減圧ガスおよび製品ガスを導入
して再加圧する各工程からなつている。[Prior Art] Conventionally, there is a pressure swing adsorption method as a gas purification method for selectively adsorbing and removing components to be removed in a raw material gas. This method consists of the following steps: (a) High-pressure raw material gas is passed through the adsorption bed, and when the adsorption bed reaches almost saturation, (b) the pressure is reduced in parallel with the gas inflow direction in step (a). Then, the outflow gas is allowed to flow into the adsorption bed in step (e) until the pressures of both are almost balanced, and (c) the pressure is further reduced to parallel flow, and the outflow gas is used as a purge gas to be used in the adsorption bed in step (d). (d) further countercurrent vacuum to a minimum pressure to desorb the adsorbent bed in combination with purge gas desorption; (e) introducing vacuum gas and product gas from step (b); It consists of each step of repressurization.

この従来の技術の代表的な例として、特公昭45
−20082がある。この技術は上述の各工程のもの
で、プレツシヤスイング吸着法の基本をなすもの
である。 As a representative example of this conventional technology,
There is −20082. This technique involves each of the above-mentioned steps and is the basis of the pressure swing adsorption method.

また、他の１例として、特開昭56−38121があ
る。この例はパージに用いる減圧ガスを、いつた
ん充填塔に貯めた後、逆流させることによつて好
ましいパージガス濃度プロフイルを得る点に特徴
がある。 Another example is Japanese Patent Application Laid-Open No. 56-38121. This example is characterized in that a preferable purge gas concentration profile is obtained by storing the reduced pressure gas used for purging in a packed column and then causing it to flow back.

［発明が解決しようとする問題点］前述の従来の技術のうち、前者は、工程(c)から
流出するガスをそのままパージガスとして使用す
るので、並流減圧時に吸着前線が次第に吸着床出
口へ進み、ついには吸着物質の破過が起り、パー
ジガスが漸進的に汚染され、再生効果が減ずると
いう問題点がある。[Problems to be Solved by the Invention] Among the above-mentioned conventional techniques, the former uses the gas flowing out from step (c) as it is as a purge gas, so the adsorption front gradually advances to the adsorption bed outlet during cocurrent pressure reduction. Eventually, the adsorbed material will break through, and the purge gas will become progressively contaminated, reducing the regeneration effect.

このため吸着材の利用効率を落して減圧時にも
破過が生じない状態で運転する必要がある。これ
は結局非吸着成分の製品の収得率が低いというこ
とにつながる。また、この欠点を改善するために
多くの提案がなされているが、装置が複雑になり
コストの上昇を招いている。 For this reason, it is necessary to reduce the utilization efficiency of the adsorbent and operate in a state where no breakthrough occurs even when the pressure is reduced. This ultimately leads to a low yield of products of non-adsorbed components. In addition, many proposals have been made to improve this drawback, but the devices become complicated and the cost increases.

後者の例は、前者の問題点を解決し、最高のパ
ージ効率を得るために、充填塔を用いてパージガ
スをこれに受け入れて、次にこれを逆に流すこと
で不純物の破過を許容できるようにしたもので、
これによつて最適のパージガスの濃度プロフイル
を得ようとするものであり、これは一応成功を収
めているが、この方法ではパージガスの大部分を
貯えることのできる容量を持つた充填塔を必要と
し、また構造的にも複雑でコスト高を招いてい
る。 The latter example solves the problem of the former, and in order to obtain the highest purge efficiency, a packed column can be used to receive the purge gas and then flow it back to allow impurity breakthrough. I did it like this,
This method attempts to obtain an optimal purge gas concentration profile, and although this method has been somewhat successful, it requires a packed column with a capacity that can store most of the purge gas. Moreover, it is structurally complex and leads to high costs.

［問題点を解決するための手段］本発明は、工程(c)から流出するガスの一部分を
ガスだめに一時貯え、工程(d)にある吸着床に流入
させるパージガスは、吸着成分の濃度の高いガス
を先に、吸着成分の濃度の低いガスをその次とす
ることを特徴とする。[Means for Solving the Problems] In the present invention, a portion of the gas flowing out from step (c) is temporarily stored in a gas reservoir, and the purge gas flowing into the adsorption bed in step (d) has a concentration of adsorbed components. It is characterized in that a gas with a high concentration of adsorbed components is placed first, followed by a gas with a low concentration of adsorbed components.

工程(c)における減圧ガス中の不純物濃度は破過
を起したところで急激に上昇したのちほぼ一定に
なること、特に製品に比べて分子量のより大きい
不純物が破過する場合にはシヤープな変化を起す
ことが見つかり、このことを利用するとパージ順
序の完全な反転は必要ではないことが我々の試験
研究中に発見された。つまり、パージガスを(1)破
過する前、(2)破過した後の２つに分けて、(2)を流
した後(1)を流すことによつて、後者の例の従来技
術とほぼ同等の効果が得られることがわかつた。 The impurity concentration in the reduced pressure gas in step (c) rises rapidly at the point where the breakthrough occurs, and then becomes almost constant. In particular, when impurities with a larger molecular weight than the product break through, there is a sharp change. During our pilot studies, we discovered that a complete reversal of the purge order was not necessary. In other words, by dividing the purge gas into two parts (1) before breakthrough and (2) after breakthrough, and by flowing (2) and then (1), the conventional technology of the latter example can be improved. It was found that almost the same effect can be obtained.

すなわち、ガスだめを利用して、 (a) (1)をガスだめにためて、(2)の後に流す、 (b) (2)をガスだめにためて、(1)を流す前に(2)を流
す、という２種類の方法があり、これによつて
簡単にパージガスの濃度プロフイルを好ましい
形にかえることができ、パージ効果を上昇させ
ることができる。 In other words, using a gas reservoir, (a) store (1) in the gas reservoir and flow it after (2), (b) store (2) in the gas reservoir, and before flushing (1), ( There are two methods: 2), which allows the concentration profile of the purge gas to be easily changed to a preferable shape and improves the purge effect.

［実施例］次に本発明を図面を参照して説明する。[Example] Next, the present invention will be explained with reference to the drawings.

第１図は本発明の方法を実施するに適した４個
の吸着床と、１個のガスだめを有する装置のフロ
ーシートである。 FIG. 1 is a flow sheet of an apparatus having four adsorption beds and one gas reservoir suitable for carrying out the method of the present invention.

主要構成要素は次の通りである。 The main components are as follows.

１〜４……吸着床、５……ガスだめ、１１，２１，３１，４１……原料ガス入口弁、１２，２２，３２，４２……オフガス出口弁、１３，２３，３３，４３……パージ弁、１４，２４，３４，４４……昇圧弁、１５，２５，３５，４５……製品ガス出口弁５３……ガスだめ入出口弁、５５……昇圧用製品ガス弁。1 to 4...adsorption bed, 5...No gas, 11, 21, 31, 41...raw material gas inlet valve, 12, 22, 32, 42...off gas outlet valve, 13, 23, 33, 43...purge valve, 14, 24, 34, 44...boost valve, 15, 25, 35, 45...Product gas outlet valve 53...Gas reservoir inlet/outlet valve, 55...Product gas valve for boosting pressure.

実施例１第２図は破過以前のガスをガスだめ５にためる
場合の時間圧力線図、第３図はその弁切替プログ
ラムである。Embodiment 1 FIG. 2 is a time-pressure diagram when gas before breakthrough is stored in the gas reservoir 5, and FIG. 3 is a valve switching program.

吸着床２に注目してステツプ毎に説明する。 Each step will be explained focusing on the adsorption bed 2.

ステツプ１〜４高圧下で弁２１を介して原料ガスを導
入、不純物を吸着して製品ガスを弁２５から取
出す。Steps 1 to 4 Raw material gas is introduced through valve 21 under high pressure, impurities are adsorbed, and product gas is taken out through valve 25.

５吸着を終了し、弁２４を介して減圧しそのガ
スを吸着床４の昇圧に用いる。5. End the adsorption, reduce the pressure via the valve 24, and use the gas to increase the pressure of the adsorption bed 4.

６弁２３を介してさらに減圧しそのガスをガス
だめ５にためる。（この時ガスの一部を吸着床
１のパージに用いることもできる。）減圧ガス
中に不純物の破過が生じはじめたら次へ進む。6. The pressure is further reduced through the valve 23 and the gas is stored in the gas reservoir 5. (At this time, a part of the gas can also be used to purge the adsorption bed 1.) When impurities begin to break through in the reduced pressure gas, proceed to the next step.

７弁２３を介して減圧したガスを弁１３を介し
て吸着床１に導入して不純物のパージを行う。7. Gas whose pressure is reduced through valve 23 is introduced into adsorption bed 1 through valve 13 to purge impurities.

８弁２３を閉じて弁２２を開け、最低圧力まで
落して不純物を脱離する。8 Close the valve 23 and open the valve 22 to reduce the pressure to the lowest level and remove impurities.

９ホールド（ガスだめ中のガスの一部を用いて
パージを受けることもできる。） 10 ホールド（減圧中の吸着床３からガスだめ５
に送られているガスの一部を用いてパージを受
けることもできる。） 11 減圧中の吸着床３からのパージガスを弁２３
を介して導入し、弁２２から脱離した不純物を
取り出す。9 Hold (Purge can also be performed using part of the gas in the gas reservoir.) 10 Hold (Purge can be carried out from adsorption bed 3 during depressurization to gas reservoir 5.
It is also possible to purge using part of the gas being sent to the ) 11 Purge gas from the adsorption bed 3 during depressurization is supplied to the valve 23.
The desorbed impurities are taken out from the valve 22.

12 ガスだめ５からパージガスを弁５３、弁２３
を介して導入し、弁２２から脱離した不純物を
取り出す。12 Purge gas from gas reservoir 5 to valve 53 and valve 23.
The desorbed impurities are taken out from the valve 22.

13 吸着床４からの減圧ガスと製品ガスの一部を
弁２４を介して受入れ昇圧する。13 The depressurized gas and part of the product gas from the adsorption bed 4 are received through the valve 24 and pressurized.

14〜16 製品ガスの一部を弁５５、弁２４を介し
て受入れ吸着圧力まで昇圧する。14-16 A part of the product gas is received through valves 55 and 24 and the pressure is increased to the adsorption pressure.

実施例１−１供給ガス組成（乾量基準vol％） H₂63.5、N₂34.7、CO0.7、CH₄1.1供給ガスは
0.9m³のカルシウムゼオライトＡを収蔵する４つ
の吸着床からなり、21Kg／cm²（絶対）および30℃
において8900Nm³／日の流量で導入され、すくな
くとも99.99％水素からなる生成ガスが4450N
m³／日の流量で放出される。この基準において供
給ガス中の水素の約79％が生成ガスとして回収さ
れる。サイクル時間26min。Example 1-1 Supply gas composition (dry basis vol%) H ₂ 63.5, N ₂ 34.7, CO 0.7, CH ₄ 1.1 The supply gas is
Consisting of 4 adsorption beds containing 0.9 m ³ of calcium zeolite A, 21 Kg/cm ² (absolute) and 30°C
was introduced at a flow rate of 8900Nm ³ /day, and the product gas consisting of at least 99.99% hydrogen was 4450Nm 3 /day.
It is released at a flow rate of m ³ /day. At this standard, approximately 79% of the hydrogen in the feed gas is recovered as product gas. Cycle time 26min.

パージガス8.6Nm³のうち純度の高いガス5.0N
m³をガスだめ（1.0m³）にたくわえて後で使用す
る。（このパージガス量は１つの吸着塔から出て
１回のパージに使用されるガス量で、１サイクル
ではこの量ｘ塔数となる。以下同じ。）実施例１−２供給ガス組成（乾量基準vol％） H₂67.5、N₂30.7、CO0.7、CH₄1.1 供給ガスは0.9m³のカルシウムゼオライトＡを
収蔵する６つの吸着床からなり、21Kg／cm²（絶
対）および30℃において15、400Nm³／日の流量
で導入され、すくなくとも99.97％水素からなる
生成ガスが8900Nm³／日の流量で放出される。こ
の基準において供給ガス中の水素の約85％が生成
ガスとして回収される。サイクル時間14min。 Purge gas ^8.6Nm3 High purity gas 5.0N
Store m ³ in a gas reservoir (1.0 m ³ ) for later use. (This purge gas amount is the gas amount that comes out of one adsorption tower and is used for one purge, and in one cycle, this amount x the number of towers. The same applies hereinafter.) Example 1-2 Feed gas composition (dry amount (Reference vol%) H ₂ 67.5, N ₂ 30.7, CO 0.7, CH ₄ 1.1 The feed gas consists of 6 adsorption beds containing 0.9 m ³ of calcium zeolite A, at 21 Kg/cm ² (absolute) and at 30 °C. A flow rate of 15,400 Nm ³ /day is introduced and a product gas consisting of at least 99.97% hydrogen is released at a flow rate of 8900 Nm ³ /day. At this standard, approximately 85% of the hydrogen in the feed gas is recovered as product gas. Cycle time 14min.

オフガスは1.4Kg／cm²で放出される。 Off-gas is released at 1.4Kg/cm ² .

パージガス3.2Nm³のうち純度の高いガス2.0N
m³をガスだめ（0.6m³）にたくわえて後で使用す
る。 Purge gas 3.2Nm ^2.0N of high purity gas
Store m ³ in a gas reservoir (0.6 m ³ ) for later use.

実施例１−３供給ガス組成（乾量基準vol％） H₂67.5、N₂30.7、CO0.7、CH₄1.1 供給ガスは0.7m³のカルシウムゼオライトＡを
収蔵する８つの吸着床からなり、21Kg／cm²（絶
対）および30℃において28，800Nm³／日の流量
で導入され、すくなくとも99.99％水素からなる
生成ガスが17，200Nm³／日の流量で放出される。
この基準において供給ガス中の水素の約88％が生
成ガスとして回収される。サイクル時間
10.5min。Example 1-3 Feed gas composition (dry basis vol%) H ₂ 67.5, N ₂ 30.7, CO 0.7, CH ₄ 1.1 The feed gas consisted of eight adsorption beds containing 0.7 m ³ of calcium zeolite A; A flow rate of 28,800 Nm ³ /day is introduced at 21 Kg/cm ² (absolute) and 30° C., and a product gas consisting of at least 99.99% hydrogen is released at a flow rate of 17,200 Nm ³ /day.
At this standard, approximately 88% of the hydrogen in the feed gas is recovered as product gas. cycle time
10.5min.

パージガス1.8Nm³のうち純度の高いガス1.2N
m³をガスだめ（0.7m³）にたくわえて後で使用す
る。 Purge gas 1.8Nm ³ , high purity gas 1.2N
Store m ³ in a gas reservoir (0.7 m ³ ) for later use.

実施例２第４図は破過以後のガスをガスだめ５にためる
場合の時間圧力線図、第５図は弁切替プログラム
である。Embodiment 2 FIG. 4 is a time-pressure diagram when gas after breakthrough is stored in the gas reservoir 5, and FIG. 5 is a valve switching program.

６弁２３を介してさらに減圧しそのガスを弁１
３を介して吸着床１に導入しパージを行う。減
圧ガス中に不純物の破過が起る前にパージを終
了する。6 The pressure is further reduced through valve 23 and the gas is sent to valve 1.
3 into the adsorption bed 1 and purging is performed. Purge ends before impurities break through into the vacuum gas.

７弁２３を介して減圧し、弁５３を通じてガス
だめ５にガスをためる。（この間に不純物の破
過が起る。）８弁２３を閉じて弁２２を開け、最低圧力まで
落して不純物を脱離する。7. Reduce the pressure through the valve 23 and store gas in the gas reservoir 5 through the valve 53. (During this time, impurity breakthrough occurs.) 8. Close valve 23 and open valve 22 to reduce the pressure to the lowest pressure and remove impurities.

９ガスだめ５より弁５３、弁２３を介してパー
ジガスを受入れ脱離した不純物を弁２２より取
り出す。9. Purge gas is received from the gas reservoir 5 through the valves 53 and 23, and the desorbed impurities are taken out through the valve 22.

10 減圧中の吸着床３からのガスを弁２３を介し
て受け入れパージを行つて脱離した不純物を弁
２２より取出す。10 Gas from the adsorption bed 3 under reduced pressure is received through the valve 23 and purged, and the desorbed impurities are taken out through the valve 22.

11〜12 ホールド 13 吸着床４からの減圧ガスと製品ガスの一部を
弁２４を介して受入れ昇圧する。11-12 Hold 13 Receives the reduced pressure gas and part of the product gas from the adsorption bed 4 via the valve 24 and increases the pressure.

実施例２−１供給ガス組成（乾量基準vol％） H₂65.0、N₂32.5、CO1.2、CH₄1.3 供給ガスは0.9m³のカルシウムゼオライトＡを
収蔵する４つの吸着床からなる吸着システムに21
Kg／cm²（絶対）、30℃において8500Nm³／日の流
量で導入され、すくなくとも99.99％の純度の水
素からなる精製ガスが4300Nm³／日の流量で放出
された。この基準において供給ガス中の約78％が
生成ガスとして回収された。Example 2-1 Feed gas composition (dry basis vol%) H ₂ 65.0, N ₂ 32.5, CO 1.2, CH ₄ 1.3 The feed gas is an adsorption system consisting of four adsorption beds containing 0.9 m ³ of calcium zeolite A. 21 to system
Kg/cm ² (absolute), at 30° C., was introduced at a flow rate of 8500 Nm ³ /day, and purified gas consisting of hydrogen with a purity of at least 99.99% was discharged at a flow rate of 4300 Nm ³ /day. Approximately 78% of the feed gas was recovered as product gas on this basis.

パージガス8.6Nm³のうち純度の低いガス4.2m³
をガス溜め（2.1m³）に貯えて後で使用した。 Purge gas 8.6Nm ³ , low purity gas 4.2m ³
was stored in a gas reservoir (2.1 m ³ ) for later use.

［発明の効果］不純物を多く含むガスを先にパージに使用する
ことで、パージガスへの破過を許容でき、パージ
ガス、吸着材の有効利用が可能となる。また、こ
の目的をはたすために用いるガスだめは単純な容
器でよく、パージガスの一部分を受入れるだけで
あるので容量も小さくてすみ、コストが安いとい
う効果がある。[Effects of the Invention] By first using a gas containing many impurities for purging, breakthrough into the purge gas can be allowed, and the purge gas and adsorbent can be used effectively. Further, the gas reservoir used for this purpose may be a simple container, and since it only receives a portion of the purge gas, the capacity can be small and the cost can be reduced.

[Brief explanation of the drawing]

第１図は本発明の方法を実施するに適した４個
の吸着床と、１個のガスだめを有する装置のフロ
ーシート、第２図は破過以前のガスをガスだめ５
にためる場合の時間圧力線図、第３図はその弁切
替プログラム、第４図は破過以後のガスをガスだ
め５にためる場合の時間圧力線図、第５図はその
弁切替プログラムである。１〜４……吸着床、５……ガスだめ。 Fig. 1 is a flow sheet of an apparatus having four adsorption beds and one gas reservoir suitable for carrying out the method of the present invention, and Fig. 2 shows a flowchart of an apparatus having four adsorption beds and one gas reservoir, and FIG.
Figure 3 shows the time pressure diagram when the gas is stored in the gas reservoir 5, Figure 3 shows the valve switching program, Figure 4 shows the time pressure diagram when the gas after breakthrough is stored in the gas reservoir 5, and Figure 5 shows the valve switching program. . 1 to 4...Adsorption bed, 5...Gas reservoir.

Claims

[Claims] 1. Selective adsorption of removed components in raw material gas 4.
(a) High-pressure raw material gas is passed through the adsorption bed, and when the adsorption bed reaches almost saturation, (b) the pressure is reduced in the same direction as the gas inflow direction in step (a), and the gas flows out. The gas is allowed to flow into the adsorption bed in step (e) until the pressures of both are approximately balanced, and (c) the pressure is further reduced to parallel flow, and the gas that flows out flows into the adsorption bed in step (d) as purge gas. (d) further countercurrent depressurization to a minimum pressure to desorb the adsorbent bed in combination with purge gas desorption, and (e) repressurization by introducing decompression gas and product gas from step (b). In the pressure swing adsorption method, which consists of each step, a portion of the gas flowing out from step (c) is temporarily stored in a gas reservoir, and the purge gas flowing into the adsorption bed in step (d) is a gas with a high concentration of adsorbed components. A gas adsorption purification method characterized in that a gas with a low concentration of adsorbed components is used next. 2 Temporarily store all or part of the gas initially flowing out from step (c) in a gas reservoir, and then immediately causing the gas flowing out to flow into the adsorption bed in step (d),
The gas adsorption purification method according to claim 1, wherein the gas stored in the gas reservoir is then introduced. 3 The first gas flowing out from step (c) is directly transferred to step (d).
The gas flowing out is temporarily stored in a gas reservoir, and this gas flows into the adsorption bed which enters step (d) next to the adsorption bed. gas adsorption purification method.