【発明の詳細な説明】[Detailed description of the invention]
本発明は気液接触を行なう通気撹拌装置に関す
る。
まず従来多用されている多孔板型通気撹拌装置
を説明する。
第１図に示す多孔板型通気撹拌装置は、液体が
入つている槽本体１内に多孔板３が取付けられ、
多孔板３の下方に気体分散器２が配置されてい
る。
気体分散器２を出た気体は液体と接触しなが
ら、多孔板３を通つて上方へと流れ、気体排気管
４から系外へ排出される。
この装置では、多孔板３の上部と下部との液体
の混合が余り期待できず、混合時間が長くなる欠
点がある。これは、槽内循環流の抑制、これによ
る気液接触面積の更新効果の阻害により、所定の
気液接触性能が低下するためである。
第２図に示す通気撹拌装置は液体が入つている
槽本体１内に上下に伸びるドラフトチユーブ５が
配置され、ドラフトチユーブ５内には多孔板３が
取付けられている。多孔板３の下方のドラフトチ
ユーブ５内に気体分散器２が配置されている。通
常のドラフトチユーブはこれによつてつくられる
ドラフトチユーブ内円状断面積とドラフトチユー
ブ外環状断面積が略等しい構造である。
ドラフトチユーブ５内に吹き込まれた気体は多
孔板３を通過して、ドラフトチユーブ５内部液体
と混合しながら上昇し、液体と分かれ、槽本体１
上部排気管４から系外へ出る。
気体に引きずられ上昇した液体は、ドラフトチ
ユーブ５の上部よりオーバーフローしてドラフト
チユーブ５の外側を下降し、再び下端よりドラフ
トチユーブ５内側に吸込まれる。
この装置は、液体の循環流が生じ、気体と液体
との接触が促進され、第１図に示す装置の欠点は
かなり解消されるが、ガス分散器をドラフトチユ
ーブ内に設置するため、構造上並びに製作上の制
約を受ける上、自らドラフトチユーブ設置固数が
限定されるため、槽内液の混合効果も必ずしも十
分でないという欠点がある。
そこで本発明は、従来の装置における上記欠点
を除くことを目的としてなされたものであり、本
発明は、槽本体内部に多孔板を取付け、同多孔板
に通常のドラフトチユーブの構造に比べ、管径の
小さい上下方向に伸びる管を連結し、同管の下端
開口より下方に気体分散器を配置したことを特徴
とする通気撹拌装置を提供するものである。この
装置によれば、気体分散器を出た気体は液体と接
触しながら上昇するが、構造上管内部には入りに
くくなり、管を避けて上昇し、管内は上部の液体
が下方へ流れる。気体は液体と接触し気泡となつ
て液体とともに多孔板の孔を通つて上方へ流れる
が、多孔板の孔を通過する際に気体、液体は再分
散され、混合性能が著しく向上する。多孔板直下
に気泡リツチの気液混合相を形成することによ
り、混合物の浮力が大きくなり、管内の液体下降
流も大きくなつて、さらに一段と混合性能がアツ
プでき、混合時間を短縮させることが可能であ
る。又、構造的に見ても、多孔板に管を取付け、
管の下方に気体分散器を配置するものであり、第
２図に示すドラフトチユーブ内に気体を供給し、
ドラフトチユーブ内を気体が上昇する装置に比
べ、気体分散器を横断面に気体が均一分散するよ
うに槽下部全面に設置でき、設置範囲の制約を受
けない。
次に本発明を第３図に示す第１の実施例に基づ
いて説明する。
槽本体１内部には、多孔板３が取付けられ、多
孔板３には中空管６が多孔板３の上下を貫通して
連結されている。中空管６の下端開口の下方の槽
本体１内に気体分散器２が配置されている。気体
分散器２から気体が送られ、気体分散器２を出た
気体は気泡を形成し液体と接触し、気液混合相と
なつて上昇する。気泡は中空管６内を通過しにく
いので中空管６を避け多孔板３の直下まで上昇す
る。気泡は液体とともに多孔板３の孔を通過する
が、このとき、気液は再分散され、多孔板３の上
方に流れる。多孔板３の上方にある液体は中空管
６内を通つて流下し、多孔板３の下方に流れる。
多孔板３の上方に流れた気体は、さらに上昇し、
槽本体１の上部の気体排出口から出てゆく。この
装置においては、液体が多孔板３の上下を循環
し、気体、液体が多孔板３で再分散されるので混
合性能が著しく増大し、混合時間が短縮され、
又、ドラフトチユーブ内部に気泡が供給されて、
ドラフトチユーブ内部を気体が上昇するものに比
べ、気体分散器を槽下方全断面に気体が分体が分
散するように設置できるため、気液接触向上させ
ることおよび構造的に見て設置が容易であること
の長所を有している。
本発明は中空管６が多孔板３の上部側には突出
しないように連結されている場合には多孔板３を
上昇する気液混合相流が、中空管６に流入する液
体に乱れを強く与えるため、流下液体の循環流量
を減少させる悪作用がある場合それを取り除くた
めに考案されたものであり、上昇気液混相流の乱
れが比較的弱まつた場所まで、中空管を上方に延
長させたもので、これにより循環流量の増大を図
ろうとするもである。
第４図に示す第２の実施例に基づいて説明す
る。第２の実施例は、多孔板３に複数本の中空管
６を連結しているが、中空管６の１部は多孔板３
の上部側に突出させないように連結され、残り
は、多孔板３の上下を貫通して連結されたもの
で、その他の構造は第１の実施例と同じである。
この装置も基本的な作用、効果は第１の実施例と
同じである。
この場合、下部中空管と上下貫通中空管及び多
孔板の管径、本数、管長さ、孔径、開孔比等々の
組合せにより、最適な条件設定ができる。
第５図に示す第３図の実施例に基づいて説明す
る。第３の実施例は第１の実施例をさらに改良し
たもので、第１の実施例における中空管６の下端
開口に多孔板７を設けたもので、その他は第１の
実施例と同じである。
第１の実施例において、中空管の径を大きくす
ると、中空管内部を気泡が上昇しはじめ、流下液
体量が減少してくる。この気泡上昇を防ぐため
に、中空管下端面に多孔板を設置したものが本実
施例であり、これにより、槽内液体の循環流量の
増大が図れる。
以上の実施例は、槽本体１内に多孔板３が１段
配置されたものであり、第１及び第３の実施例で
は中空管６が１本連結されたものであるが、中空
管６は複数本連結してもよく、又、中空管６に設
けられる多孔板７は下端開口位置に限られること
はない。
次に多孔板３を二段配置した２つの実施例に基
づいて説明する。
まず第６図に示す第４の実施例について説明す
る。
槽本体１内に２つの多孔板３，３′が取付けら
れ、夫々の多孔板３，３′には中空管６が夫々の
多孔板３，３′を貫通して取付けられている。
多孔板３の下部で中空管６の下端開口より下方
には気体分散器２が配置されている。
気体分散器２を出た気体は、液分と接触し、気
液混合相となつて上昇する。気液混合相は、気体
が中空管６内を通過しにくいので、中空管６を避
けて多孔板３直下に至り、その後、多孔板３の孔
を通過し、多孔板３と多孔板３′の間に流入す
る。気液混合相が多孔板３の孔を通過する際に液
分、気体分が再分散される。多孔板３と多孔板
３′との間の気液混合相がさらに上昇し、同様に
多孔板３′の孔を通過し多孔板３′上部に流れ、気
体は気体排出管４により外部へ排出される。気液
混合相が多孔板３′の孔を通過する際、さらに再
分散される。一方多孔板３′上部の液体の１部は
中空間６を通つて流下し多孔板３と多孔板３′と
の間に流入し、多孔板３と多孔板３′との間の１
部の液体はさらに中空管６を通つて流下し、液体
の循環が発生する。
本装置は、第１ないし第３の実施例に比べ、各
段において液体循環部分が多数あるため多孔板上
下の流体が均一的に分散循環する上、２段にして
いるため、液深の大きい装置においては特に上下
方向の液体混合が促進され、混合時間の短縮が図
れる。
次に第７図に示す第５の実施例に基づいて説明
する。
第５の実施例は第４図の実施例における中空管
６の１部の中空管６′を多孔板３，３′を同時に貫
通して連結した、すなわち中空管６′の上端開口
が多孔板３′の上部に位置し、下端開口が多孔板
３の下部に位置するよう連結されたもので、その
他の構造は第４の実施例と同じであり、説明は省
略する。多孔板３′上部の循環液体の１部は、中
空管６′により直接多孔板３の下方に流下するも
のであり、第４の実施例に比べ、多孔板により遠
く仕切られた槽上部および槽下部の液体混合が容
易に促進され、槽全体の混合時間の一層の短縮が
期待できる。
以上、第４，５の実施例に基づいて説明したが
多孔板は２段以上としてもよく、又、気体分散器
は、夫々の多孔板の下方に設けたものでもよい。
次に本発明を具体的実験例に基づいて説明す
る。
The present invention relates to an aeration stirring device that performs gas-liquid contact. First, a perforated plate type aeration stirring device, which has been widely used in the past, will be explained. The perforated plate type aeration stirring device shown in FIG. 1 has a perforated plate 3 installed inside a tank body 1 containing liquid.
A gas distributor 2 is arranged below the perforated plate 3. The gas exiting the gas distributor 2 flows upward through the perforated plate 3 while contacting the liquid, and is discharged from the system through the gas exhaust pipe 4. This device has the drawback that it is difficult to expect that the liquid will mix well between the upper and lower parts of the porous plate 3, and the mixing time will be long. This is because the predetermined gas-liquid contact performance is degraded due to suppression of the circulation flow in the tank and the resulting inhibition of the effect of updating the gas-liquid contact area. In the aeration stirring device shown in FIG. 2, a draft tube 5 extending vertically is arranged in a tank body 1 containing liquid, and a perforated plate 3 is installed inside the draft tube 5. A gas distributor 2 is arranged in a draft tube 5 below the perforated plate 3. A normal draft tube has a structure in which the inner circular cross-sectional area of the draft tube and the outer circular cross-sectional area of the draft tube are approximately equal. The gas blown into the draft tube 5 passes through the perforated plate 3, rises while mixing with the liquid inside the draft tube 5, separates from the liquid, and flows into the tank body 1.
It exits the system from the upper exhaust pipe 4. The liquid dragged up by the gas overflows from the upper part of the draft tube 5, descends on the outside of the draft tube 5, and is sucked into the inside of the draft tube 5 again from the lower end. This device generates a circulating flow of liquid, promoting contact between gas and liquid, and eliminates many of the drawbacks of the device shown in Figure 1. In addition to being subject to manufacturing constraints, the number of installed draft tubes is also limited, so there is a drawback that the mixing effect of the liquid in the tank is not necessarily sufficient. Therefore, the present invention has been made with the aim of eliminating the above-mentioned drawbacks of conventional devices.The present invention has a perforated plate installed inside the tank body, and a draft tube structure on the perforated plate. The present invention provides an aeration stirring device characterized in that vertically extending pipes having small diameters are connected and a gas disperser is disposed below the opening at the lower end of the pipes. According to this device, the gas leaving the gas distributor rises while coming into contact with the liquid, but due to its structure, it is difficult to enter the inside of the tube, so it avoids the tube and rises, and inside the tube, the upper liquid flows downward. The gas comes into contact with the liquid, turns into bubbles, and flows upward through the holes in the perforated plate together with the liquid, but when passing through the holes in the perforated plate, the gas and liquid are redispersed, significantly improving the mixing performance. By forming a bubble-rich gas-liquid mixed phase directly under the perforated plate, the buoyancy of the mixture increases, and the downward flow of liquid within the tube also increases, further improving mixing performance and shortening the mixing time. It is. Also, from a structural point of view, the pipe is attached to the perforated plate,
A gas distributor is placed below the tube, and gas is supplied into the draft tube shown in Figure 2.
Compared to a device in which gas rises in a draft tube, the gas distributor can be installed over the entire lower part of the tank so that the gas is uniformly dispersed in the cross section, and there are no restrictions on the installation range. Next, the present invention will be explained based on a first embodiment shown in FIG. A perforated plate 3 is attached inside the tank body 1, and a hollow tube 6 is connected to the perforated plate 3 by passing through the upper and lower sides of the perforated plate 3. A gas distributor 2 is arranged within the tank body 1 below the opening at the lower end of the hollow tube 6 . Gas is sent from the gas distributor 2, and the gas that exits the gas distributor 2 forms bubbles, contacts the liquid, and rises as a gas-liquid mixed phase. Since the bubbles are difficult to pass through the hollow tube 6, they avoid the hollow tube 6 and rise to just below the perforated plate 3. The air bubbles pass through the holes in the perforated plate 3 together with the liquid, but at this time, the gas and liquid are redispersed and flow above the perforated plate 3. The liquid above the perforated plate 3 flows down through the hollow tube 6 and flows below the perforated plate 3.
The gas flowing above the perforated plate 3 further rises,
The gas exits from the gas outlet at the top of the tank body 1. In this device, the liquid circulates above and below the perforated plate 3, and the gas and liquid are redispersed by the perforated plate 3, so the mixing performance is significantly increased and the mixing time is shortened.
Also, air bubbles are supplied inside the draft tube,
Compared to a draft tube in which the gas rises inside, the gas distributor can be installed so that the gas is dispersed over the entire cross section of the bottom of the tank, which improves the gas-liquid contact and is structurally easier to install. have the advantage of being In the present invention, when the hollow tubes 6 are connected so as not to protrude above the perforated plate 3, the gas-liquid mixed phase flow rising on the perforated plate 3 is disturbed by the liquid flowing into the hollow tubes 6. It was devised to remove any negative effects that may reduce the circulating flow rate of the flowing liquid, and the hollow tube is inserted until the turbulence of the ascending air-liquid multiphase flow has weakened relatively. It is extended upward and is intended to increase the circulation flow rate. A description will be given based on the second embodiment shown in FIG. In the second embodiment, a plurality of hollow tubes 6 are connected to the perforated plate 3, and some of the hollow tubes 6 are connected to the perforated plate 3.
The remaining structure is the same as that of the first embodiment, except that the porous plate 3 is connected so that it does not protrude from the upper side of the porous plate 3, and the remaining parts are connected through the upper and lower portions of the perforated plate 3.
This device also has the same basic functions and effects as the first embodiment. In this case, optimal conditions can be set by combining the lower hollow tube, the upper and lower hollow tubes, the number of tubes, the tube length, the hole diameter, the aperture ratio, etc. Description will be made based on the embodiment shown in FIG. 3 shown in FIG. The third embodiment is a further improvement of the first embodiment, in which a perforated plate 7 is provided at the lower end opening of the hollow tube 6 in the first embodiment, and the rest is the same as the first embodiment. It is. In the first embodiment, when the diameter of the hollow tube is increased, bubbles begin to rise inside the hollow tube, and the amount of flowing liquid decreases. In this embodiment, a perforated plate is installed on the lower end surface of the hollow tube in order to prevent bubbles from rising, thereby increasing the circulation flow rate of the liquid in the tank. In the above embodiment, one stage of perforated plate 3 is arranged in the tank body 1, and in the first and third embodiments, one hollow pipe 6 is connected. A plurality of tubes 6 may be connected, and the perforated plate 7 provided in the hollow tube 6 is not limited to the lower end opening position. Next, two embodiments in which the perforated plates 3 are arranged in two stages will be described. First, a fourth embodiment shown in FIG. 6 will be described. Two perforated plates 3, 3' are installed in the tank body 1, and a hollow tube 6 is installed in each of the perforated plates 3, 3' by passing through each of the perforated plates 3, 3'. A gas distributor 2 is arranged below the opening of the lower end of the hollow tube 6 in the lower part of the perforated plate 3 . The gas exiting the gas distributor 2 comes into contact with the liquid, becomes a gas-liquid mixed phase, and rises. Since it is difficult for the gas to pass through the hollow tube 6, the gas-liquid mixed phase avoids the hollow tube 6 and reaches directly below the perforated plate 3, and then passes through the holes in the perforated plate 3 and connects the perforated plate 3 and the perforated plate. 3'. When the gas-liquid mixed phase passes through the holes of the perforated plate 3, the liquid and gas components are redispersed. The gas-liquid mixed phase between the perforated plate 3 and the perforated plate 3' rises further, passes through the holes in the perforated plate 3', and flows to the upper part of the perforated plate 3', and the gas is discharged to the outside through the gas discharge pipe 4. be done. When the gas-liquid mixed phase passes through the holes of the perforated plate 3', it is further redispersed. On the other hand, a part of the liquid on the upper part of the perforated plate 3' flows down through the hollow space 6 and flows between the perforated plate 3 and the perforated plate 3'.
The remaining liquid further flows down through the hollow tube 6, and liquid circulation occurs. Compared to the first to third embodiments, this device has a large number of liquid circulation parts in each stage, so the fluid above and below the perforated plate is uniformly distributed and circulated, and since it has two stages, the liquid depth is large. In the device, liquid mixing is particularly promoted in the vertical direction, and the mixing time can be shortened. Next, a description will be given based on a fifth embodiment shown in FIG. In the fifth embodiment, a part of the hollow tubes 6' of the hollow tubes 6 in the embodiment shown in FIG. is located at the upper part of the perforated plate 3', and the lower end opening is located at the lower part of the perforated plate 3.The other structure is the same as that of the fourth embodiment, and a description thereof will be omitted. A part of the circulating liquid in the upper part of the perforated plate 3' flows down directly to the lower part of the perforated plate 3 through the hollow pipe 6', and compared to the fourth embodiment, a part of the circulating liquid in the upper part of the perforated plate 3' flows down directly to the lower part of the perforated plate 3. Liquid mixing at the bottom of the tank is easily promoted, and it is expected that the mixing time for the entire tank will be further shortened. Although the explanation has been made based on the fourth and fifth embodiments, the perforated plates may be arranged in two or more stages, and the gas distributor may be provided below each perforated plate. Next, the present invention will be explained based on specific experimental examples.
【表】【table】
【表】
表１に示す仕様の装置を用いて実験したとこ
ろ、第９図に示す結果を得た。
なお、実験は次のようにして行なわれた。
混合時間の測定は本体の槽上部からNaCl溶液
を投入し、最下段、最上部の多孔板の夫々の、下
部側から経時的に液を採取し、電気伝導度計を用
いて、NaCl濃度を測定した。
又、各採取位置でのNaCl濃度が定常的に一致
する時間をもつて、混合時間（θM）とした。
第９図から、ａ，ｂは、混合時間が長く、すな
わち混合性能が悪く、ｃ，ｄ，ｅ，ｆ，ｇ，ｈ，
は混合時間が極めて短い。すなわち混合性能が良
いことがわかる。
又、中空管長さの効果があることもわかる。[Table] An experiment was conducted using an apparatus having the specifications shown in Table 1, and the results shown in FIG. 9 were obtained. The experiment was conducted as follows. To measure the mixing time, pour the NaCl solution into the tank from the top of the main unit, sample the solution over time from the bottom side of the bottom and top porous plates, and measure the NaCl concentration using an electrical conductivity meter. It was measured. Furthermore, the time during which the NaCl concentrations at each sampling position were consistently consistent was defined as the mixing time (θ M ). From FIG. 9, a, b have long mixing time, that is, poor mixing performance, c, d, e, f, g, h,
The mixing time is extremely short. In other words, it can be seen that the mixing performance is good. It can also be seen that the length of the hollow tube has an effect.
【図面の簡単な説明】[Brief explanation of the drawing]
第１図、第２図は夫々従来の通気撹拌装置を示
す図、第３図ないし第７図は夫々本発明の第１な
いし第６の実施例を示す図、第８図は、具体的実
験の結果を示すグラフである。
１……槽本体、２……気体分散器、３，３′７
……多孔板、４……気体排出口、５……ドラフト
チユーブ、６，６′……中空管。
Figures 1 and 2 are diagrams showing a conventional aeration stirring device, Figures 3 to 7 are diagrams showing first to sixth embodiments of the present invention, respectively, and Figure 8 is a diagram showing a concrete experiment. This is a graph showing the results. 1... Tank body, 2... Gas disperser, 3, 3'7
...Perforated plate, 4...Gas outlet, 5...Draft tube, 6,6'...Hollow tube.