JP6078287B2 - Gas-liquid contact method and water deoxygenation method using the same - Google Patents

Gas-liquid contact method and water deoxygenation method using the same Download PDF

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JP6078287B2
JP6078287B2 JP2012222557A JP2012222557A JP6078287B2 JP 6078287 B2 JP6078287 B2 JP 6078287B2 JP 2012222557 A JP2012222557 A JP 2012222557A JP 2012222557 A JP2012222557 A JP 2012222557A JP 6078287 B2 JP6078287 B2 JP 6078287B2
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申一 関口
申一 関口
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Description

本発明は、水中の溶存酸素等を窒素やアルゴン等の不活性ガスと置換することで除去するストリッピング技術による気液接触方法、及びそれを応用した水の脱酸素方法に関する。   The present invention relates to a gas-liquid contact method using a stripping technique for removing dissolved oxygen in water by replacing it with an inert gas such as nitrogen or argon, and a water deoxygenation method using the same.

〔溶存酸素〕
溶存酸素は、一般的には空気中の21%の酸素濃度分圧に比例した液体への酸素の溶解量である。水の場合には、図7に示す様な温度に依存した溶解特性を示す。
〔ガスストリッピング技術〕
ガスストリッピングとは、液相と気相のガス組成の比率を等しくすることで、液体中のガス成分の調整を行う方法である。
〔脱酸素技術〕
(蒸気式脱気法)
従来からボイラの給水の脱気で実施されていた方法であり、高所に設置された脱気槽中に、蒸気を吹込み、給水を大気圧下で沸点付近の温度に保つことにより、水中のガス成分を脱気する。
(真空脱気法)
水を沸点に保つに当たり、大気圧よりも低い圧力中で実施する方法である。
(膜脱気法)
酸素透過膜と呼ばれる酸素が溶解しやすい膜を用い、膜の反対側を低圧にすることで、水中の溶存酸素が膜を通過して、低圧側に移行することを利用して脱酸素を行う方法である。
(窒素置換法)
窒素置換法とは、リアクターと呼ばれる接触器若しくはエアレーターと呼ばれる散水器等を用いて、水中の溶存酸素と窒素をヘンリーの法則に従って置換することにより、水中の溶存酸素を減少させる方法で、ガスストリッピング技術の一形態である。
[Dissolved oxygen]
Dissolved oxygen is generally a dissolved amount of oxygen in a liquid proportional to a partial pressure of oxygen concentration of 21% in air. In the case of water, it exhibits a temperature-dependent dissolution characteristic as shown in FIG.
[Gas stripping technology]
Gas stripping is a method for adjusting gas components in a liquid by equalizing the ratio of the gas composition of the liquid phase to the gas phase.
[Deoxygenation technology]
(Steam type deaeration method)
This is a method that has been practiced by deaeration of boiler feedwater in the past.By blowing steam into a deaeration tank installed at a high location, the feedwater is kept at a temperature near the boiling point under atmospheric pressure. The gas component is degassed.
(Vacuum degassing method)
In order to keep water at the boiling point, the method is carried out at a pressure lower than atmospheric pressure.
(Membrane degassing method)
Oxygen permeable membrane called oxygen permeable membrane is used, and the other side of the membrane is made low pressure, so that dissolved oxygen in water passes through the membrane and moves to the low pressure side to perform deoxygenation Is the method.
(Nitrogen replacement method)
Nitrogen replacement is a method of reducing dissolved oxygen in water by replacing dissolved oxygen and nitrogen in water according to Henry's law using a contactor called a reactor or a sprinkler called an aerator. It is a form of stripping technology.

(窒素置換−気中水滴接触型)
静止型リアクターや分散板等を配置した接触塔の上部から水を散水し、塔内に窒素を吹き込むことで、霧状になった水滴と気液接触させる方法である。
(窒素置換−水中気泡接触型)
エアレーターと呼ばれる機械式の攪拌機により水を運動させるとともに、水中に微細気泡を分散させるものや、圧縮気体を水中に噴出させる際に微細気泡を発生させる方法である。
(窒素置換−単段接触法)
窒素ガスと水との接触を1つの接触装置で行い、純度の低下した窒素ガスを外部に排出する方法である。装置がコンパクトになり、装置も簡単に構成できるが、水中の酸素濃度を低下させる為には、大量の窒素が必要になる。
(窒素置換−多段接触法)
窒素ガスと水との接触を複数の接触装置で行い、最終段の接触装置の窒素ガスをその前段の接触装置のガスとして再利用することで、窒素の消費量を抑制できるが、装置が大型化し、装置も複雑化する。
〔過飽和〕
溶液の中に溶質が過剰に含まれた状態を言い、本発明においては、水の中にその温度及び圧力条件下でヘンリーの法則に従った溶存気体の存在量より過剰に溶存気体が含まれている状態を言う。例えば、廃水処理等で用いられる加圧浮上法は、高圧水の中に空気を溶存させ、常圧に戻すことで、過飽和状態の空気が微細気泡を発生する原理を利用している。
(Nitrogen replacement-in-air contact type)
In this method, water is sprinkled from the upper part of the contact tower in which a stationary reactor, a dispersion plate, and the like are arranged, and nitrogen is blown into the tower to bring it into contact with mist-like water droplets.
(Nitrogen substitution-underwater bubble contact type)
In this method, water is moved by a mechanical stirrer called an aerator and fine bubbles are generated when fine bubbles are dispersed in water or when compressed gas is ejected into water.
(Nitrogen substitution-single-stage contact method)
In this method, nitrogen gas and water are brought into contact with one contact device, and the nitrogen gas with reduced purity is discharged to the outside. Although the apparatus becomes compact and the apparatus can be easily configured, a large amount of nitrogen is required to reduce the oxygen concentration in water.
(Nitrogen substitution-multistage contact method)
Nitrogen gas and water can be contacted by multiple contact devices, and the nitrogen gas in the final stage contact device can be reused as the gas for the previous contact device, thereby reducing nitrogen consumption. And the device becomes complicated.
[Supersaturated]
A state in which a solute is excessively contained in a solution.In the present invention, dissolved gas is contained in water in excess of the amount of dissolved gas in accordance with Henry's law under the temperature and pressure conditions. Say that state. For example, a pressurized flotation method used in wastewater treatment or the like uses the principle that supersaturated air generates fine bubbles by dissolving air in high-pressure water and returning to normal pressure.

〔気体移送手段〕
気体を移送する手段であるが、低差圧のものは送風機、高差圧のものはコンプレッサーと呼ばれる。又、大気圧以下の圧力から大気圧へ気体を移送する場合には真空ポンプ等と呼ばれる。低差圧のものは遠心式や摩擦式で構成され、高差圧のものは多段の遠心式や容積式等が用いられる。又、高速流体の運動エネルギーで気体を移送する手段として、エゼクターやアスピレーター等がある。気体の移送は、圧力の変化に伴う熱エネルギーと運動エネルギーの変化を伴う為、液体移送と同一質量で比べた場合に極めて大きな動力を必要とする。
〔インゼクター/エゼクター〕
高速の流体のエネルギーを利用して、負圧を生み出すことの出来る器具である。空気や蒸気等を駆動気体として用いる気体インゼクター(エゼクター)や、アスピレーターと呼ばれる水を駆動流体とした負圧発生装置が一般的である。
〔不活性ガス〕
不活性ガスとは、対象となる環境下において、酸化や還元或いは酸性やアルカリ性等を示さず、且つ他の元素等との結合等を行うことの無いガスをいう。代表的なガスは、ヘリウム、ネオン、アルゴン等の希ガス族元素であるが、窒素ガスも一般的な環境下においては、不活性ガスとして用いることができる。
(Gas transfer means)
As a means for transporting gas, one having a low differential pressure is called a blower, and one having a high differential pressure is called a compressor. Moreover, when transferring gas from the pressure below atmospheric pressure to atmospheric pressure, it is called a vacuum pump. A low differential pressure type is constituted by a centrifugal type or a friction type, and a high differential pressure type is a multistage centrifugal type or a positive displacement type. Moreover, there are an ejector, an aspirator and the like as means for transferring a gas with the kinetic energy of a high-speed fluid. Since the transfer of gas involves a change in thermal energy and kinetic energy associated with a change in pressure, a very large power is required when compared with a liquid transfer with the same mass.
[Injector / Ejector]
It is a device that can generate negative pressure using the energy of high-speed fluid. A gas injector (ejector) that uses air, steam, or the like as a driving gas, or a negative pressure generator that uses water as a driving fluid, which is called an aspirator, is common.
[Inert gas]
An inert gas refers to a gas that does not exhibit oxidation, reduction, acidity, alkalinity, or the like and does not bind to other elements or the like in a target environment. A typical gas is a rare gas group element such as helium, neon, or argon, but nitrogen gas can also be used as an inert gas in a general environment.

〔気体吸引手段〕
気体吸引手段とは、一般的には回転動力を利用した真空ポンプ(水流式、レシプロ式、スクリュー式、スクロール式等)を示すが、流体の高速気流を利用するインゼクターやエゼクターも気体吸引手段である。
〔液体移送手段〕
液体移送手段とは、一般的に回転動力により駆動されるポンプを示すが、気体エネルギーを利用したダイヤフラムやピストン等の往復動を利用したポンプや高速気流による吸引力を利用したインゼクター等も液体移送能力を持つ。
[Gas suction means]
The gas suction means generally indicates a vacuum pump (water flow type, reciprocating type, screw type, scroll type, etc.) that uses rotational power, but injectors and ejectors that use high-speed fluid flow are also gas suction means. It is.
[Liquid transfer means]
The liquid transfer means generally indicates a pump driven by rotational power. However, a pump using a reciprocating motion such as a diaphragm using a gas energy or a piston, an injector using a suction force by a high-speed air flow, or the like is also a liquid. Has transfer capability.

〔温度検知手段〕
白金測温対、熱電対、サーミスター等の温度センサーとそのアンプから構成され、温度信号を電気的な信号に変換したり、予め設定された温度に到達した時にON・OFFする信号を出力するタイプの電気的検知手段等である。この他に、バイメタルや流体の温度膨張を利用した機械的動作により、予め設定された温度に到達した時にON・OFFの信号を出力する機械的検知手段等がある。
〔流量検知手段〕
流量検知手段とは、流体の差圧、流速、容積、質量等を計測して電気的な信号に変換する流量計と呼ばれるもの等である。この他には、一定容量のタンクの減量や増量を検知したり、ポンプの規定流量から作動時間等により流量を推定する方法等がある。
[Temperature detection means]
Consists of temperature sensors such as platinum thermocouples, thermocouples, thermistors, etc., and their amplifiers, which convert temperature signals into electrical signals and output signals that turn on and off when a preset temperature is reached. Type of electrical detection means. In addition, there are mechanical detection means for outputting an ON / OFF signal when a preset temperature is reached by a mechanical operation utilizing the temperature expansion of bimetal or fluid.
[Flow detection means]
The flow rate detection means is a so-called flow meter that measures the differential pressure, flow velocity, volume, mass, etc. of the fluid and converts it into an electrical signal. In addition to this, there are methods such as detecting a decrease or an increase in a fixed capacity tank or estimating the flow rate from the specified flow rate of the pump based on the operation time.

〔脱酸素における処理効率、容積効率、エネルギー使用率、窒素使用率〕
本発明において、処理効率とは、ヘンリーの法則に従った溶存ガス濃度が気相の組成とバランスした状態を100%とした場合の効率のことである。順流式では、 最高でも100%であるが、 対向流式気液接触機構の場合には、100%以上の処理効率も容易に得られる。
容積効率とは、定格処理能力の流量を水及びガスの貯留槽の容積で除した値若しくは装置全体の容積で除した値を言い、通常1時間当たりの処理能力を除したものが判りやすい。容積効率が高いほど装置がコンパクトとなる。
エネルギー使用率は、動力エネルギーを定格処理能力で除した値である。この値が少ない程効率の良い装置である。
窒素使用率は、1t当たりの必要窒素量のことであり、処理効率100%の場合が理論窒素使用率となる。単段の場合と2段以上の接触単位で水と窒素ガスを対向させる場合で使用率は異なるが、理論値は計算で求めることができる。尚、実際の窒素使用率は、水温に応じて変化可能な設備と固定的である設備とで大幅に変動を生じる。また、負荷変動に追従できる設備と、できない設備とでも大幅に変動を生じる。
[Processing efficiency, volumetric efficiency, energy usage rate, nitrogen usage rate in deoxygenation]
In the present invention, the processing efficiency is the efficiency when the state in which the dissolved gas concentration according to Henry's law is balanced with the composition of the gas phase is 100%. In the forward flow type, the maximum is 100%, but in the case of the counter flow type gas-liquid contact mechanism, a processing efficiency of 100% or more can be easily obtained.
The volumetric efficiency refers to a value obtained by dividing the flow rate of the rated processing capacity by the volume of the water and gas storage tanks or the volume of the entire apparatus, and is usually easily obtained by dividing the processing capacity per hour. The higher the volumetric efficiency, the more compact the device.
The energy usage rate is a value obtained by dividing motive energy by the rated processing capacity. The smaller this value, the more efficient the device.
The nitrogen usage rate is a necessary nitrogen amount per 1 ton, and a theoretical nitrogen usage rate is obtained when the treatment efficiency is 100%. Although the usage rate is different between a single stage and a case where water and nitrogen gas are opposed to each other in two or more contact units, a theoretical value can be obtained by calculation. The actual nitrogen usage rate varies greatly between the equipment that can be changed according to the water temperature and the equipment that is fixed. In addition, there is a significant fluctuation between equipment that can follow load fluctuations and equipment that cannot.

〔カルマン渦〕
流れの中にその流れの一部を障害する障害物を置いた時に、その下流側に交互に現れる渦列のことである。
〔水中での気泡の浮上速度〕
水中での気泡の浮上速度は、気泡が完全な球体であると仮定した場合には、浮力と水中での球体の抵抗力がバランスする速度となることから計算される。
気泡の直径が0.3mmで約0.05m/s、0.5mmで約0.15m/s、1mmで約0.6m/s、1.5mmで約1. 4m/s、2mmで約2.4m/sである。又、水深が深くなるに従い、気泡径が小さくなる為、浮上速度は低下する。
[Karman vortex]
It is a vortex street that appears alternately on the downstream side when an obstacle that obstructs part of the flow is placed in the flow.
[Bubble ascent rate in water]
If the bubble is assumed to be a perfect sphere, the levitation speed of the bubble in water is calculated from the speed at which the buoyancy and the resistance force of the sphere in water are balanced.
The bubble diameter is about 0.05 m / s at 0.3 mm, about 0.15 m / s at 0.5 mm, about 0.6 m / s at 1 mm, and about 1. at 1.5 mm. It is about 2.4 m / s at 4 m / s and 2 mm. In addition, as the water depth increases, the bubble diameter decreases, so the ascent rate decreases.

〔対向流式多段窒素脱気装置の課題〕
多段式窒素脱気装置は、水質や水温の制約が無く、窒素の使用量を抑制できる優れた脱気方法である(例えば、特許文献1、2参照)。しかし、従来実用化されていた気液接触機構は、対向流式気液接触式である為、処理流速を上げることが困難な為、コンパクトに設計することに限界がある。ガスを循環利用すると、対向流の効果が無くなることから、ガス量を概ね150NL/t以下に低下させることが困難である(水温の高い水でも窒素ガス量が変わらない。)。さらに、処理流量の変化への対応が困難で、常に定格状態での運転となる為、低負荷時の窒素使用率が大幅に悪化する。以上のような課題があった。
[Problems of counterflow multi-stage nitrogen deaerator]
The multi-stage nitrogen deaerator is an excellent deaeration method that can suppress the amount of nitrogen used without any restrictions on water quality or water temperature (see, for example, Patent Documents 1 and 2). However, since the gas-liquid contact mechanism that has been put into practical use is a counter-flow type gas-liquid contact type, it is difficult to increase the processing flow rate, so there is a limit to designing it compactly. When the gas is circulated, the effect of the counterflow is lost, so it is difficult to reduce the gas amount to approximately 150 NL / t or less (the amount of nitrogen gas does not change even with high water temperature water). In addition, it is difficult to cope with changes in the processing flow rate, and since the operation is always performed in the rated state, the nitrogen usage rate at low load is greatly deteriorated. There were problems as described above.

〔エアレーター式の課題〕
エアレーターとは、水中で羽根車を回転させ、中心部に生じる負圧により気液混合を行う方法であり、水中気泡型の気液接触を行う方法である(例えば、特許文献3参照)。しかし、流速の殆ど無い槽内に1〜2ヶ所の攪拌装置を備えても、エアレーションを複数回受ける場所と殆ど受けないでショートパスする領域を生じてしまい、脱気効率を高める為には長い滞留時間を必要とする。また、接触効率を上昇させる為に、槽内の水の流速が乱流になる程度の大量の気体を水中に噴霧するか、水流を生じさせるには、大きなエネルギーが必要になる。さらに、回転軸の気体シールを行わないとガス純度が低下し、処理効率が低下するが、回転軸の気体シールは機構が複雑となり、コスト低減が困難等の課題があった。
[Aerator-type issues]
An aerator is a method in which an impeller is rotated in water and gas-liquid mixing is performed by a negative pressure generated at the center, and an underwater bubble-type gas-liquid contact is performed (see, for example, Patent Document 3). However, even if one or two stirrers are provided in a tank having almost no flow velocity, a place for receiving aeration a plurality of times and a region for short-passing with little reception are generated, which is long for improving the deaeration efficiency. Retention time is required. Further, in order to increase the contact efficiency, a large amount of energy is required to spray a large amount of gas into the water or to generate a water flow so that the flow rate of water in the tank becomes a turbulent flow. Further, if the rotary shaft gas seal is not performed, the gas purity is lowered and the processing efficiency is lowered. However, the rotary shaft gas seal has a problem that the mechanism is complicated and it is difficult to reduce the cost.

〔順流式多段窒素脱気装置の課題〕
一方で、順流式多段脱気装置では、流速が上げられることや流速の変化にも対応しやすいこと等対向流式の課題を解決できるメリットがある(例えば、特許文献4〜6参照)。しかし、密度差の問題から順流式では水中気泡型の気液接触となる為、気体の液体への注入や流体の攪拌を行う為に大きなエネルギーが必要となる。これらのこと等から、多段式で採用することは容易ではなく、実用例が無かった。
[Problems of forward-flow multi-stage nitrogen deaerator]
On the other hand, the forward flow type multi-stage deaeration device has an advantage that it can solve the problems of the counter flow type such as increasing the flow velocity and easily responding to changes in the flow velocity (see, for example, Patent Documents 4 to 6). However, because of the density difference problem, the forward flow type gas-liquid contact is an underwater bubble type, and a large amount of energy is required to inject the gas into the liquid and to stir the fluid. For these reasons, it is not easy to adopt a multistage system, and there are no practical examples.

特開2004−261691号公報Japanese Patent Application Laid-Open No. 2004-261691 特開2009−106943号公報JP 2009-106943 A 特開平11−137989号公報Japanese Patent Application Laid-Open No. 11-137989 特開2001−129304号公報JP 2001-129304 A 特開2003−001008号公報JP 2003-001008 A 特開2004−298793号公報JP 2004-298793 A

本発明は、気液接触方法において、コンパクトで低動力な構成の気液接触装置により、気液接触を行うことができる気液接触方法、及びそれを応用した水の脱酸素方法を提供することを目的とする。そして、より具体的には、多段式窒素脱気方法において、コンパクトで低動力且つ多段構成を取り、窒素ガスの消費量を抑制できる脱酸素装置を提供することを目的とする。   The present invention provides a gas-liquid contact method capable of performing gas-liquid contact by a gas-liquid contact device having a compact and low-power configuration in a gas-liquid contact method, and a water deoxygenation method using the same. With the goal. More specifically, an object of the present invention is to provide a deoxygenation apparatus that can take a compact, low power, multistage configuration and suppress the consumption of nitrogen gas in a multistage nitrogen degassing method.

本発明の請求項1にかかる気液接触方法は、処理水と対象ガスを混合循環しながら、その一部を処理済み水及び処理済みガスとして系外に排出し、バランスした量の処理前水と処理前ガスを流入させる循環型の気液接触方法であって、対象ガスが大気である場合を除き密閉構造で、貯留部および気相部を備える貯留槽と、対象ガスが大気である場合を除き密閉構造で、上部に給水口、下部に排水口および気室部を備える気液接触塔と、前記貯留槽と前記給水口とを接続する循環管路と、前記貯留槽と前記排水口とを接続する接触管路と、前記貯留槽と前記気液接触塔との間の液体を循環する液体移送手段と、を備え、前記貯留槽の気相部と、前記気液接触塔の気室部とは、対象ガスが大気である場合を除きガス循環管路により連通され、前記接触管路の断面積は、前記貯留槽の喫水面と、前記接触管路の流速と圧力損失から決まる下流側水面が前記給水口より低くなり、且つ流速が0.15m/s以上5m/s未満となる値に設定され、前記気液接触塔の水平方向の断面積は、循環する水量が、重力加速度に従って落下する時の流速に対応する断面積よりも大きく、下流側水面以降の下降流速が0.15m/s以上5m/s未満となる値に設定され、前記気液接触塔の垂直方向の高さは、前記給水口から落下する自由落下水の下流側水面への衝突速度が0.5m/s以上となる値に設定されることを特徴とする方法である。 In the gas-liquid contact method according to claim 1 of the present invention, a part of the pre-treatment water is discharged as a treated water and a treated gas while mixing and circulating the treated water and the target gas. Gas-liquid contact method for inflowing a gas before treatment with a sealed structure except when the target gas is air, and a storage tank having a storage part and a gas phase part, and when the target gas is air A gas-liquid contact tower having a water supply port at the top, a drain port and an air chamber at the bottom, a circulation line connecting the storage tank and the water supply port, the storage tank and the drain port And a liquid transfer means for circulating a liquid between the storage tank and the gas-liquid contact tower, a gas phase portion of the storage tank, and a gas in the gas-liquid contact tower The chamber is communicated by a gas circulation line except when the target gas is the atmosphere, Sectional area of Sawakanro includes a draft surface of the reservoir, the downstream water surface, which is determined from the flow rate and the pressure loss of the contact line is lower than the water supply port, and the flow rate is 0.15 m / s or more 5 m / s The horizontal cross-sectional area of the gas-liquid contact tower is set to be less than the cross-sectional area corresponding to the flow speed when the amount of circulating water falls according to the gravitational acceleration, and the descending flow velocity after the downstream water surface Is set to a value that is greater than or equal to 0.15 m / s and less than 5 m / s, and the vertical height of the gas-liquid contact tower is such that the collision speed of the free fall water falling from the water supply port with the downstream water surface is 0. The method is characterized in that the value is set to a value of 5 m / s or more.

本発明によれば、前記液体移送手段の運転により水が気液接触塔上部から自由落下空間内(気室部)で落下し、自由落下空間内に形成される下流側水面に衝突することで、自由落下空間に存在していたガスを気泡として巻き込み、接触管路内で順流型の水中気泡型の気液接触を行う。また、水がガスと共に貯留槽に戻ることで、水の自由落下空間内が貯留槽内気圧より低圧となり、下流側水面の上流側と貯留槽の気相をガス循環管路で連通させると、水の循環を行うだけで貯留槽のガスを吸引し循環させることができる。
本構成を一段として、この様に水とガスが循環している状態で、水経路の最前段の水循環系に原水を供給し、最後段の水循環系から処理水を得る場合、最後段のガス循環系に必要量の窒素ガスを供給し、最前段のガス循環系から排気することで、処理水量に応じた窒素ガス量で脱酸素処理を行うことができる。
尚、対象ガスが大気である場合には、対象ガスを循環再利用するメリットが少ないので、気液接触塔から直接空気を吸込み、貯留槽で直接外気排気する方法が合理的である。
According to the present invention, by the operation of the liquid transfer means, water falls from the upper part of the gas-liquid contact tower in the free fall space (air chamber part) and collides with the downstream water surface formed in the free fall space. Then, the gas existing in the free fall space is entrained as bubbles, and the forward flow type underwater bubble type gas-liquid contact is performed in the contact line. In addition, when water returns to the storage tank together with the gas, the free fall space of water becomes lower than the internal pressure of the storage tank, and when the upstream side of the downstream water surface and the gas phase of the storage tank are communicated with each other through a gas circulation line, By simply circulating water, the gas in the storage tank can be sucked and circulated.
With this configuration as one stage, when water and gas are circulated in this way, when raw water is supplied to the water circulation system at the front stage of the water path and treated water is obtained from the water circulation system at the last stage, the gas at the last stage By supplying a necessary amount of nitrogen gas to the circulatory system and exhausting it from the gas circulatory system at the front stage, deoxygenation treatment can be performed with a nitrogen gas amount corresponding to the amount of treated water.
When the target gas is the atmosphere, there are few merits of circulating and reusing the target gas. Therefore, it is reasonable to suck air directly from the gas-liquid contact tower and exhaust the outside air directly from the storage tank.

本発明の請求項2にかかる気液接触方法は、前記接触管路が、下降管路と、前記貯留槽内に開口部を持つ上昇管路とを備えることを特徴とする。
本発明においては、下降管路を備えることで、下降管効果により接触効率が向上し、上昇管路を備えることで上昇管効果により、管路の圧力損失と気液分離速度が向上する。
The gas-liquid contact method according to claim 2 of the present invention is characterized in that the contact conduit includes a descending conduit and an ascending conduit having an opening in the storage tank.
In the present invention, by providing the downcomer pipe, the contact efficiency is improved by the downcomer pipe effect, and by providing the riser pipe, the pressure loss and the gas-liquid separation speed of the pipe line are improved by the ascending pipe effect.

本発明の請求項3にかかる気液接触方法は、前記気液接触塔が、前記気室部を流下する液体流中に液体流の一部の速度を低下させる障害手段と、その下流側に前記ガス循環管路またはガス供給管路の開口部とを備えることを特徴とする。
本発明によれば、液体の粘性と表面張力及びカルマン渦の効果により液体流内にガスが巻き込まれ、下流側水面に自由落下水が衝突する際における気泡の巻き込み量が増大し、気体吸引量が増加する事から処理効率が向上する。
The gas-liquid contact method according to claim 3 of the present invention is characterized in that the gas-liquid contact tower includes a obstacle means for reducing a part of the velocity of the liquid flow in the liquid flow flowing down the gas chamber, and a downstream side thereof. And an opening of the gas circulation pipe or the gas supply pipe.
According to the present invention, gas is entrained in the liquid flow due to the effect of the viscosity and surface tension of the liquid and the Karman vortex, and the amount of entrained bubbles when free-falling water collides with the downstream water surface increases, and the amount of gas suction Increases the processing efficiency.

本発明の請求項4にかかる気液接触方法は、前記ガス循環管路の経路上に、気体移送手段を備えることを特徴とする。
本発明によれば、処理水量が増加した場合に、気体移送手段を用いることで、気体循環量を増加させることができるので、処理効率を向上できる。更に、この気体移送手段に蒸気エゼクターを用いると、気体循環量の増大と同時に、蒸気の凝集効果により処理効率が更に上昇すると伴に、エゼクター排気蒸気が直ちに凝縮する事による負圧効果により、エゼクター効率を高めることができる。また、蒸気エネルギーを給水の熱として回収できるので、極めて高効率の装置となる。
The gas-liquid contact method according to claim 4 of the present invention is characterized in that a gas transfer means is provided on the path of the gas circulation conduit.
According to the present invention, when the amount of treated water increases, the gas circulation rate can be increased by using the gas transfer means, so that the treatment efficiency can be improved. Further, when a vapor ejector is used for this gas transfer means, the treatment efficiency is further increased due to the coagulation effect of the vapor at the same time as the gas circulation amount is increased, and at the same time, the ejector exhaust vapor is condensed due to the negative pressure effect due to immediate condensation. Efficiency can be increased. Further, since the steam energy can be recovered as heat of the feed water, the apparatus becomes extremely efficient.

本発明の請求項5にかかる水の脱酸素方法は、請求項1から請求項4のいずれか一項に記載の気液接触方法において、前記対象ガスとして不活性ガスを用い、前記処理水中のガス組成を前記不活性ガスのガス組成に置換させることを特徴とする。
本発明によれば、上記のように、コンパクトで低動力な構成の気液接触装置により、気液接触を行うことができるので、コンパクトな脱酸素技術を提供することができる。
The water deoxygenation method according to claim 5 of the present invention is the gas-liquid contact method according to any one of claims 1 to 4, wherein an inert gas is used as the target gas, The gas composition is substituted with the gas composition of the inert gas.
According to the present invention, as described above, gas-liquid contact can be performed by the gas-liquid contact device having a compact and low-power configuration, so that a compact deoxygenation technique can be provided.

〔順流方式の採用〕
(対向流式の限界)
気液接触を行う方法としては、対向流式が接触効率が高いとされ、従来の高効率脱酸素装置ではこの方法が採用されていた。対向流式では、接触器単位で濃度勾配を持たせることができるので、接触器の流速を下げ、接触段数を増やすことにより、単段であっても少ない窒素量で脱酸素が行える。例えば、脱酸素を窒素で行うことを考えた場合に、単段で理論上接触効率100%の場合700NL/tの窒素ガスが必要な場合でも、対向流式の場合には接触部を複数段に分けることにより、200L程度の窒素ガス量で同一の溶存酸素水を作成することも可能である。しかし、この特性は、水流速を上げるとガスが水と同一方向に流れることから、コンパクトに設計することが困難であることと、先に提出した特許出願(特願2011−147584)でも述べているが、窒素ガス量が150NL/t程度を下回ると、ガスの過飽和現象により、窒素ガスが水に吸収されてしまい、処理効率が急激に悪化することが判っており、窒素使用率を減少させるには限界があった。又、水やガスの循環を行うと、濃度勾配がなくなる為、一定量の処理水を流し続ける必要があり、負荷の要求水量に応じたオンデマンド対応が困難であるので、部分負荷時には窒素ガス量を無駄に消費してしまう欠点も解決が困難であった。
(順流方式の課題)
順流方式は、水とガスが同一流を構成する気液接触方法であり、流速を早くすることができるので、コンパクト化しやすく、接触単位でガスの循環を行うことや水の循環を行うことが可能で、オンデマンド対応が容易である。しかし、接触器単位では濃度勾配が無い為、処理効率が最高でも100%であることや、繰り返し気液接触させる為の動力コストの増大等克服しなければならない課題も多かった。
[Adoption of forward flow system]
(Limit of counter flow type)
As a method for performing gas-liquid contact, the counter flow type is considered to have high contact efficiency, and this method has been adopted in the conventional high-efficiency deoxygenation apparatus. In the counter-flow type, since a concentration gradient can be provided for each contactor, deoxygenation can be performed with a small amount of nitrogen even in a single stage by lowering the flow rate of the contactor and increasing the number of contact stages. For example, when considering deoxygenation with nitrogen, even if 700 NL / t of nitrogen gas is necessary in the case of a single stage theoretically with a contact efficiency of 100%, a plurality of contact portions are formed in the counterflow type. It is also possible to create the same dissolved oxygen water with a nitrogen gas amount of about 200 L. However, this characteristic is also described in the patent application (Japanese Patent Application No. 2011-147484) filed earlier because it is difficult to design compactly because the gas flows in the same direction as water when the water flow rate is increased. However, it is known that when the amount of nitrogen gas is less than about 150 NL / t, the nitrogen gas is absorbed by water due to the gas supersaturation phenomenon, and the processing efficiency is rapidly deteriorated, and the nitrogen usage rate is reduced. There were limits. In addition, when water or gas is circulated, the concentration gradient disappears, so it is necessary to keep a certain amount of treated water flowing, and it is difficult to respond on demand according to the required amount of load. It was difficult to solve the disadvantage of wasting the amount.
(Problems with the forward flow method)
The forward flow method is a gas-liquid contact method in which water and gas constitute the same flow, and since the flow velocity can be increased, it is easy to make it compact, and it is possible to circulate gas and water in contact units. Yes, it can be easily handled on demand. However, since there is no concentration gradient for each contactor, there are many problems that must be overcome, such as that the processing efficiency is 100% at the maximum and the power cost for repeated gas-liquid contact is increased.

(順流方式の改善の要点)
順流式で処理効率を高めながら、コンパクト化と省エネルギーを図るには、下記(i)〜(iv)の課題をクリアする必要がある。
(i)水に対しての接触ガス量を増加させること。
(ii)水の運動量を増加させること。
(iii)気体の混合の為に大きなエネルギーや装置を必要としないこと。
(iv)単段当たりのエネルギー投入量を出来るだけ抑制すること。
これらの課題をクリアする為に、順流式で投入エネルギーを最小としながら、多量のガスを気液接触させることができる水の自由落下効果を利用した気液接触方法を考案した。
(Key points for improving the forward flow system)
In order to achieve downsizing and energy saving while improving the processing efficiency by the forward flow type, it is necessary to clear the following problems (i) to (iv).
(I) To increase the amount of contact gas with water.
(Ii) Increase water momentum.
(Iii) No large energy or equipment is required for gas mixing.
(Iv) Reduce the amount of energy input per single stage as much as possible.
In order to solve these problems, we have devised a gas-liquid contact method that utilizes the free-falling effect of water that allows a large amount of gas to come into gas-liquid contact with a forward flow system while minimizing input energy.

〔水の自由落下効果を利用した水循環式気液接触方法〕
(気液の混合)
通常管路内を流れる水に気体を吸引させる為には、ベルヌーイの定理に従った流速により管路内を負圧にする必要があること。又、水とガスとは表面張力、粘度、密度等の物性が全く異なることから水の中に気体を分散させることも、気体の中に水を分散させることもどちらも、エネルギーを消費しやすい気液混合の工程がエネルギー消費を抑制する上で課題となっていた。
(自由落下効果)
水を自由落下させると、自由落下中は気体と液体の密度差が無視できるので、水塊の全周にガスが存在する、分散の第一条件を容易に実現できる。管路内で自由落下状態を作るには、垂直に立てた管路に上部から水を供給する時、その液体が落下する時に、気体抵抗を無視すれば重力加速度に従った流下速度になるが、その速度において必要な断面積よりも太い口径の管路を用い、その管路内に気体を満たすことで自由落下条件を作ることができる。本発明に必要な自由落下の距離は、下流側水面への衝突速度から求めることができる。有効な最低衝突速度は0.5m/s以上でこれ以下の衝突速度では気泡が殆ど生じない。衝突速度は水の落下方法により異なり、自由落下部入口における下降流速がゼロである場合には1.5m、流速3mの場合で凡そ0.5mで、下流側水面に落下する時の速度が4m/s程度になり、この衝突速度が処理効率や容積効率の面で有利である。又、自由落下による水の加速は、水の摩擦抵抗や粘性の影響を除外できるので極めて高効率である。
[Water circulation type gas-liquid contact method using free fall effect of water]
(Mixing of gas and liquid)
In order to draw gas into the water that normally flows in the pipeline, it is necessary to create a negative pressure in the pipeline at a flow rate according to Bernoulli's theorem. Also, since water and gas have completely different physical properties such as surface tension, viscosity, density, etc., it is easy to consume energy both in the case of dispersing gas in water and in the case of dispersing water in gas. The process of gas-liquid mixing has been a problem in suppressing energy consumption.
(Free fall effect)
When water is allowed to fall freely, the density difference between gas and liquid can be ignored during free fall, so the first condition of dispersion in which gas is present all around the water mass can be easily realized. In order to create a free fall state in a pipeline, when water is supplied from the top to a vertically standing pipeline, when the liquid falls, if the gas resistance is ignored, the flow velocity will follow the gravitational acceleration. A free fall condition can be created by using a pipe having a diameter larger than the required cross-sectional area at that speed and filling the pipe with a gas. The free fall distance necessary for the present invention can be determined from the collision speed on the downstream water surface. The effective minimum collision speed is 0.5 m / s or more, and bubbles are hardly generated at collision speeds below this. The collision speed varies depending on the water dropping method. When the descending flow velocity at the free fall portion entrance is zero, it is 1.5 m, when the flow velocity is 3 m, it is approximately 0.5 m, and the velocity when falling to the downstream water surface is 4 m. This collision speed is advantageous in terms of processing efficiency and volumetric efficiency. In addition, the acceleration of water by free fall is extremely efficient because the influence of water friction and viscosity can be excluded.

(自由落下後の下流側水面での周囲気体の巻き込み効果)
自由落下している液体が、下流側水面に衝突すると、衝突部分の周囲の気体を巻き込み、水中に気泡が生じる。これは丁度滝つぼが気泡で白くなる状況と同一である。これは、落下する水と下流側水面の間に挟まれた気体が、水の表面張力により閉じ込められ気泡を形成するので、水中に気体を噴射する方法に比べて、極めて効率が良い。尚、自由落下部の管路径が、落下速度に応じた必要断面積と近い場合には、管路内面に水流が接触しやすく、気泡の発生効率が低下する為、一般的には必要管路の2倍以上の断面積であることが望ましい。自由落下させる水のノズルは、配管の端面の様な単純なものでも良いし、複数の ノズルやパンチプレートの様な多穴式のものでも良いが、整い過ぎた直線流の場合は、落下水と下流側水面の衝突面の気体が少なくなること、水滴径が小さくなりすぎると、空気抵抗による速度低下により水面への打撃力が弱まることから、衝突面での気泡生成が悪化する。
(Effect of surrounding gas on the downstream water surface after free fall)
When the free-falling liquid collides with the downstream water surface, the gas around the collision part is entrained and bubbles are generated in the water. This is exactly the same as the situation where the waterfall is white with bubbles. This is very efficient compared to the method of injecting gas into water because the gas sandwiched between the falling water and the downstream water surface is trapped by the surface tension of the water to form bubbles. Note that when the pipe diameter of the free fall part is close to the required cross-sectional area corresponding to the drop speed, the water flow tends to come into contact with the inner surface of the pipe and the bubble generation efficiency decreases. It is desirable that the cross-sectional area is twice or more. The free-falling water nozzle may be as simple as the end face of the pipe, or it may be a multi-hole type such as multiple nozzles or punch plates. If the gas on the collision surface on the downstream water surface is reduced and the water droplet diameter is too small, the impact force on the water surface is weakened due to the speed reduction due to air resistance, and the bubble generation at the collision surface is deteriorated.

(接触管の効果)
下流側水面(衝突面)の位置は、概ね気液接触器と連通している貯留槽の液面に、接触管内流速から求められる水頭分を加算した位置に調整される。接触管流速が0.5m/sの場合には、+12mm程度であるが、3m/sの場合には460mm程度、下流側水面が上昇することになるので、自由落下部の必要高さ、循環流量とを考慮した上で、接触管の口径を選定する必要がある。又、自由落下部の衝突面以降の下降流速が概ね0.15m/s以下である場合、直径0.5mm以上の気泡は浮上してしまうので、下降流速が低すぎることは処理効率の低下を伴う。この様に、気泡が接触管内に巻き込まれることにより、自由落下部の気体量が減少する為、自由落下部の気相や上流側に開口部を設ければ、外部の気体を吸引する様になる。尚、自由落下部と接触管間に狭窄部を設ける場合には、流体の抵抗を少なくする為、テーパー状に狭窄することが望ましく、位置は貯留槽の喫水面付近とするのが効率が良い。狭窄部を喫水面より高い位置とした場合には、その位置から狭窄部を通過する為の水頭を生じるので、自由落下部の高さを高くする必要があること。狭窄部を喫水面より低い位置とした場合には、喫水面以下は水頭とならないので、低流速部の距離が長くなるだけでメリットが少ない為である。
(Effect of contact tube)
The position of the downstream water surface (collision surface) is adjusted to a position obtained by adding the head of water obtained from the flow velocity in the contact pipe to the liquid surface of the storage tank that is generally in communication with the gas-liquid contactor. When the contact pipe flow velocity is 0.5 m / s, it is about +12 mm, but when it is 3 m / s, the downstream water surface rises by about 460 mm. It is necessary to select the diameter of the contact tube in consideration of the flow rate. In addition, when the descending flow velocity after the collision surface of the free-falling portion is approximately 0.15 m / s or less, bubbles with a diameter of 0.5 mm or more will rise, so that the descending flow velocity is too low will reduce the processing efficiency. Accompany. In this way, since the amount of gas in the free fall part is reduced by entraining the bubbles in the contact tube, if an opening is provided in the gas phase or upstream side of the free fall part, external gas is sucked. Become. When a constriction is provided between the free fall part and the contact tube, it is desirable to constrict the taper in order to reduce the resistance of the fluid, and the position is efficient near the draft surface of the storage tank. . If the stenosis part is positioned higher than the draft surface, a water head for passing the stenosis part from that position is generated, so the height of the free fall part must be increased. This is because, when the constricted portion is positioned lower than the draft surface, the portion below the draft surface does not become a water head, so that only the distance of the low flow velocity portion is increased and there are few merits.

(下降管の効果)
接触管は下降流を形成し、流速は1m/s以上が望ましく、0.15m/sより遅いと0.5mm以上の気泡は逆流してしまう他、設備コストの面からも不利である。下降流においては、気泡径が大きいと管内滞留時間が増加し、微細気泡は乱流に沿った動きとなることから接触効率の向上が期待できると共に、気泡が会合して成長しても、水流により扁平となり、再分散する為処理効率の悪化やガスの逆流を防止できる。又、水深が深くなると、気体の溶解量が増加し、気液接触効率が上がる。尚、5m/s以上の高流速では、高い水頭圧を必要とする為、自由落下の水面と狭窄部の距離が大きくなる為、自由落下部の長さを長くする必要があり、ポンプの動力や設備面でのメリットが少なくなる。
(Effect of downcomer)
The contact tube forms a downward flow, and the flow rate is desirably 1 m / s or more. If the flow rate is slower than 0.15 m / s, bubbles of 0.5 mm or more flow backward, and this is disadvantageous in terms of equipment cost. In the downward flow, if the bubble diameter is large, the residence time in the pipe increases, and the fine bubbles move along the turbulent flow, so that the contact efficiency can be improved. As a result, it becomes flat and re-dispersed, so that deterioration of processing efficiency and gas backflow can be prevented. Further, as the water depth increases, the amount of gas dissolved increases and the gas-liquid contact efficiency increases. Note that at high flow rates of 5 m / s or higher, high head pressure is required, so the distance between the free-falling water surface and the constricted part increases, so the length of the free-falling part must be increased, and the pump power And there is less merit in terms of equipment.

(上昇管の効果)
上昇管は、接触管(下降管)の最下部と接続され、貯留槽内に開口部を有する管路であるが、中を流れる混合流体の水深が浅くなるに従い、気泡の容積が大きくなることと、上昇流においては、気泡径が大きい程上昇速度が速くなる為、周囲の微小気泡を巻き込み上昇力が増加するので、接触管路と上昇管路の圧力損失を相殺することができる。更に、その効果により過飽和になっていた気体分子の微細気泡を巻き込み易く、微細な気泡を残さないことで、気液分離の向上が期待できる。特に開口部が上向きであると、気泡の上昇力を有効に活用できるので有利である。従って、上昇管を備えることで、接触管の下降する深度を深くすることができるので、気液接触時間と水圧効果により、気液接触効率が向上する。
(Rise pipe effect)
The ascending pipe is connected to the lowermost part of the contact pipe (downcomer pipe) and has an opening in the storage tank, but the volume of bubbles increases as the water depth of the mixed fluid flowing through it becomes shallower. In the upward flow, the larger the bubble diameter, the faster the rising speed, and the surrounding microbubbles are entrained to increase the upward force, so that the pressure loss between the contact line and the upward line can be offset. Further, it is easy to entrain fine bubbles of gas molecules that are supersaturated due to the effect, and improvement of gas-liquid separation can be expected by leaving no fine bubbles. In particular, when the opening is upward, it is advantageous because the rising force of the bubbles can be effectively utilized. Therefore, by providing the ascending pipe, the depth at which the contact pipe descends can be increased, so that the gas-liquid contact efficiency is improved by the gas-liquid contact time and the water pressure effect.

(ガス混合比と循環率)
順流式気液接触により、ガス交換を行う場合、気泡径と接触時間が同一であると仮定した場合には、水に対するガス体積が多い方が処理効率は高くなる。一方で、ガスの体積を増加させる為には、エネルギーの投入量も多くなることが一般的である。この為、オンデマンドで使用する場合に、処理水量が少ない場合には、自動的に循環回数が増加するので、ガス容積を少なめとし、処理水量が増加する場合には循環回数が減少することからガス容積を多めにすることで、処理効率と投入エネルギーのバランスを取ることができる。
(Gas mixing ratio and circulation rate)
When gas exchange is performed by forward-flow gas-liquid contact, if it is assumed that the bubble diameter and the contact time are the same, the treatment efficiency becomes higher as the gas volume with respect to water is larger. On the other hand, in order to increase the gas volume, the amount of energy input is generally increased. For this reason, when used on demand, if the amount of treated water is small, the number of circulations automatically increases, so the gas volume is reduced, and if the amount of treated water increases, the number of circulations decreases. By increasing the gas volume, the processing efficiency and the input energy can be balanced.

(投入エネルギー)
この循環と気液接触を行う為に必要なエネルギーは、水を3循環させた場合を考えると、ポンプ効率0.5の場合で、0.03kw/t(0.1666666×液密度×0.05t/分×1.6m)/0.5(ポンプ効率)と極めて少ない投入エネルギーで気液接触を行うことができる。因みに、3循環とは自由落下効果の基本的な方法により、処理効率が90%以上となる最低循環数であり、前提として循環量1tに対して200NLのガスを混合することが出来、3循環で600NLのガスが、処理水1tに対して接触する。尚、ガスの混合効率の改善により、循環量1tに対して300NLのガスを混合することが出来れば、2循環で600NLのガスが処理水1tに対して接触するので、容積効率やエネルギー使用率を高めることができる。
(Input energy)
The energy required for this circulation and gas-liquid contact is 0.03 kw / t (0.1666666 × liquid density × 0. Gas-liquid contact can be performed with very little input energy of 05 t / min × 1.6 m) /0.5 (pump efficiency). By the way, 3 circulation is the lowest circulation number with a processing efficiency of 90% or more by the basic method of free fall effect. As a premise, 200 NL of gas can be mixed with 1 t of circulation volume. Then, 600 NL of gas comes into contact with the treated water 1t. If 300 NL of gas can be mixed with 1 t of circulation volume by improving gas mixing efficiency, 600 NL of gas will come into contact with 1 t of treated water in 2 cycles, so volume efficiency and energy usage rate Can be increased.

(水の自由落下効果を利用した水循環式気液接触方法のまとめ)
本方式は、低圧損大流量の水循環を行う過程で、気液混合と気液接触を効率的に行うことができるので、処理効率が高く、エネルギー効率も高い。同時に、貯留槽を含めた気液接触機構において、気泡発生と水循環がシリーズであるので、ショートパスや過多接触が無く、エアレーター式と比較した場合に、滞留時間を大幅に短縮できるので容積効率が高い。従って、気液接触機構が順流式であることによる流速の高速化と、ガスを繰り返し循環できることから、下記(i)〜(iv)の作用が達成できる。
(i)気液接触機構がコンパクトになる。
(ii)消費電力が少なくなる。
(iii)オンデマンド運転が可能になる。
(iv)原水の溶存酸素(DO)に応じた窒素使用率での運転が可能になる。
(Summary of water-circulating gas-liquid contact method using free fall effect of water)
Since this method can efficiently perform gas-liquid mixing and gas-liquid contact in the process of water circulation with a low pressure loss and a large flow rate, the processing efficiency is high and the energy efficiency is also high. At the same time, in the gas-liquid contact mechanism including the storage tank, since bubble generation and water circulation are series, there is no short path or excessive contact, and the residence time can be greatly shortened compared to the aerator type, so volume efficiency Is expensive. Therefore, the following actions (i) to (iv) can be achieved because the gas-liquid contact mechanism is a forward flow type and the flow rate is increased and the gas can be circulated repeatedly.
(I) The gas-liquid contact mechanism becomes compact.
(Ii) Power consumption is reduced.
(Iii) On-demand operation becomes possible.
(Iv) Operation at a nitrogen usage rate according to the dissolved oxygen (DO) of raw water becomes possible.

水の自由落下を利用した気液接触機構の一例を示す説明図。Explanatory drawing which shows an example of the gas-liquid contact mechanism using the free fall of water. 水の自由落下を利用した気液接触機構の一例を示す説明図。Explanatory drawing which shows an example of the gas-liquid contact mechanism using the free fall of water. 水の自由落下を利用した気液接触機構の一例を示す説明図。Explanatory drawing which shows an example of the gas-liquid contact mechanism using the free fall of water. 水の自由落下を利用した気液接触機構の一例を示す説明図。Explanatory drawing which shows an example of the gas-liquid contact mechanism using the free fall of water. 水の自由落下を利用した気液接触機構の一例を示す説明図。Explanatory drawing which shows an example of the gas-liquid contact mechanism using the free fall of water. 自由落下部の気体吸引力を高める気液接触機構の一例を示す説明図。Explanatory drawing which shows an example of the gas-liquid contact mechanism which raises the gas suction force of a free fall part. 蒸気インゼクターを用いた気液接触機構の一例を示す説明図。Explanatory drawing which shows an example of the gas-liquid contact mechanism using a steam injector. 送風機を用いた気液接触機構の一例を示す説明図。Explanatory drawing which shows an example of the gas-liquid contact mechanism using an air blower. 自由落下を利用した4段脱気装置の構成の一例を示す説明図。Explanatory drawing which shows an example of a structure of the four-stage deaeration apparatus using free fall. 4段自由落下式と蒸気アシストを併用した場合の処理効率を示すグラフ。The graph which shows the processing efficiency at the time of using together a 4-stage free fall type | formula and steam assist. 4段オンデマンド式と2段対向流式の負荷変動による窒素使用率を示すグラフ。The graph which shows the nitrogen usage rate by the load fluctuation of a 4-stage on-demand type and a 2-stage counterflow type. 大気バランス下の水への溶存酸素及び溶存窒素量を示すグラフ。The graph which shows the amount of dissolved oxygen and dissolved nitrogen in water under air balance.

〔実施形態1〕
以下、本発明の第1実施形態を図面に基づいて説明する。
図1dは、気液接触機構の構成と動作を説明する一例である。貯留槽(1)には、水入口(7)、水出口(8)、排気管路(17)、ガス循環管路(15)が接続されている他、貯留槽内に設置された液体移送手段(4)から連通する水循環管路(5)を経由して、気液接触塔(10)、接触管路(13)を経由する水循環を行う構成となっている。気液接触塔(10)は、上部が水循環管路(5)と接続されており、その下部の口径が太くなっており、自由落下部(11)を構成している。なお、貯留槽(1)にて液体が貯留している貯留部を貯留槽水側(2)といい、気体のある気相部を貯留槽気室側(3)という。
水循環管路(5)の自由落下部への接続が下向きの場合には、流速が自由落下部(11)の高さを補うことが可能である。水循環管路(5)は、流速として1〜4m/s程度が望ましく、それに合わせて水循環量から口径を決定する。尚、自由落下部(11)への噴出し部は、図の様に直角や内部に突き出した様な形状が、自由落下部の側面部を伝わる水流量を減少させるので望ましい。自由落下部(11)の口径は、最低でも水循環管路(5)の口径を上回る必要があるが、同一口径の場合には、壁面に水が付着する為、落下効果が減少する。この為、直径で2倍以上、断面積で4倍以上の口径の管路を用いることが望ましい。衝突面(18)は、貯留槽喫水面(19)に接触管路の流速に相当する水頭圧を加えた高さ付近に自動的に生成される。
液体移送手段(4)は、水中ポンプを使用しており、揚程1.5mの時に吐出量60m/hの能力を持っている。
Embodiment 1
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
FIG. 1d is an example illustrating the configuration and operation of the gas-liquid contact mechanism. The storage tank (1) is connected to a water inlet (7), a water outlet (8), an exhaust pipe (17), and a gas circulation pipe (15), as well as a liquid transfer installed in the storage tank. It is configured to perform water circulation via the gas-liquid contact tower (10) and the contact pipeline (13) via the water circulation pipeline (5) communicating from the means (4). The upper part of the gas-liquid contact tower (10) is connected to the water circulation pipe (5), and the diameter of the lower part thereof is thick, thereby constituting a free fall part (11). In addition, the storage part which the liquid is storing in the storage tank (1) is called the storage tank water side (2), and the gaseous-phase part with gas is called the storage tank air chamber side (3).
When the connection of the water circulation pipeline (5) to the free fall part is downward, the flow velocity can compensate for the height of the free fall part (11). The water circulation pipe (5) desirably has a flow rate of about 1 to 4 m / s, and the diameter is determined from the water circulation amount accordingly. In addition, as for the ejection part to the free fall part (11), the shape which protrudes at right angles or inside as shown in the figure reduces the flow rate of the water transmitted through the side part of the free fall part, and is desirable. The diameter of the free fall part (11) needs to exceed the diameter of the water circulation pipe (5) at the minimum. However, in the case of the same diameter, water drops on the wall surface, so that the drop effect is reduced. For this reason, it is desirable to use a pipe line having a diameter that is twice or more in diameter and four or more times in cross-sectional area. The collision surface (18) is automatically generated in the vicinity of a height obtained by applying a head pressure corresponding to the flow velocity of the contact pipe line to the storage tank draft surface (19).
The liquid transfer means (4) uses a submersible pump and has a discharge capacity of 60 m 3 / h when the head is 1.5 m.

本実施形態では、 自由落下部(11)、 接触管路(13)を同一口径としており、循環流量60m/hで内径150mmであり、気泡を除いた流速は接触管路(13)で1m/sとなっている。貯留槽は500Lの容積で、約350Lが水で150Lが気相となる構成であり、60m/hの循環量の時に1循環は約21秒となる。自由落下空間には約800mm自由落下後に3.9m/sの下向きの流速で、衝突面(18)の水面で気泡を生成している。衝突面(18)は下流側の流速により、約50mm程貯留槽喫水面(19)より上の位置となっている。この条件で、大気圧の気体の吸引量は、12Nm/h程度で循環水量の20%(容積比)程度である。
ガス循環管路(15)は貯留槽の気相部と自由落下部を連通しており、前記の量のガスを貯留槽との間で循環しながら気液接触を行う。新たなガスはガス循環管路(15)の途中のガス供給管路(16)から供給され、自由落下部(11)に供給され、余剰のガスは排気管路(17)を経由して系外に排気される。
In this embodiment, the free fall part (11) and the contact pipe line (13) have the same diameter, the circulation flow rate is 60 m 3 / h, the inner diameter is 150 mm, and the flow rate excluding bubbles is 1 m in the contact pipe line (13). / S. The storage tank has a capacity of 500 L, about 350 L is water, and 150 L is a gas phase, and one circulation takes about 21 seconds when the circulation rate is 60 m 3 / h. In the free fall space, bubbles are generated on the water surface of the collision surface (18) at a downward flow rate of 3.9 m / s after free fall of about 800 mm. The collision surface (18) is positioned above the reservoir draft surface (19) by about 50 mm due to the downstream flow rate. Under this condition, the suction amount of the gas at atmospheric pressure is about 12 Nm 3 / h and about 20% (volume ratio) of the circulating water amount.
The gas circulation line (15) communicates the gas phase part of the storage tank and the free fall part, and makes gas-liquid contact while circulating the above amount of gas between the storage tank. New gas is supplied from the gas supply line (16) in the middle of the gas circulation line (15) and supplied to the free fall part (11), and excess gas passes through the exhaust line (17). Exhausted outside.

図1eは、前記の構成と大きな変化は無いが、自由落下部(11)にガス循環管路(15)とガス供給管路(16)が備えられており、自由落下部下部は接触管路(13)と同一口径で、貯留槽(1)の貯留槽喫水面(19)下に開口している。図1dも図1eも、自由落下を利用することで、極めて単純な構造でありながら、水循環を行うだけで、ガスを吸引しながら循環させ、気液接触することができることと、ガス経路の上流側からの純度の高いガスを、自由落下部(11)に導入することができる。   In FIG. 1e, there is no significant change from the above configuration, but the free fall part (11) is provided with a gas circulation line (15) and a gas supply line (16), and the lower part of the free fall part is a contact line. It has the same diameter as (13) and opens below the storage tank draft surface (19) of the storage tank (1). Both FIG. 1d and FIG. 1e have an extremely simple structure by utilizing free fall, but by performing water circulation, gas can be circulated while being sucked and brought into gas-liquid contact, and upstream of the gas path. High purity gas from the side can be introduced into the free fall part (11).

〔実施形態2〕
以下、本発明の第2実施形態を図面に基づいて説明する。
図1aは、実施例1の気液接触効率を高めた気液接触機構とその動作を示した一例である。水循環管路(5)から気液接触塔(10)までの構成は図1dと同一であるが、気液接触塔の下部の接触管路(13)が下降管路(13a)と上昇管路(14)より構成されており、更に接触管路(13)の最下部は貯留槽(1)の底面よりも下に設置されている。実施形態1の場合と流速や配管口径が同一条件の場合には、ガスの吸引量は変わらないが、下降管路を水とガスの混合流体が下降するに従い、水圧効果でガスの水への溶け込み量が増加し、気液接触効率が向上する。この気液混合流体は、見かけの密度が低いので、ガス混合比が増加するに従い、深部に到達することが本来は困難となる。しかし、上昇管路(14)を通過する時には、貯留槽(1)内の水よりも密度が低いことから上昇する力を生じさせるので、深い位置まで混合流体を到達させることができる。又、水圧効果により過飽和となった混合流体は、常圧下に戻した場合に、微細気泡を生じて、分離時間が長くなることから容積効率を上げることが困難となる。しかし、上昇管路(14)内で水の上昇に伴い水圧が減少することから、気泡径が大きくなることと、気泡径が大きくなると上昇速度が上昇することから、周囲の微細気泡を巻き込み気液分離を高速に行うことができる。この為、貯留槽は350Lの容積で、約200Lが水で150Lが気相となる構成であり、60m/hの循環量の時に1循環は約10秒となる。
[Embodiment 2]
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 1a is an example showing a gas-liquid contact mechanism with enhanced gas-liquid contact efficiency and its operation according to the first embodiment. The structure from the water circulation line (5) to the gas-liquid contact tower (10) is the same as that shown in FIG. 1d, but the contact line (13) at the lower part of the gas-liquid contact tower is composed of a descending line (13a) and an ascending line. (14), and the lowermost part of the contact pipe (13) is installed below the bottom surface of the storage tank (1). In the case where the flow velocity and the pipe diameter are the same as in the case of the first embodiment, the gas suction amount does not change, but as the mixed fluid of water and gas descends in the downcomer, the water pressure effect causes the gas to flow into the water. The amount of penetration increases and the gas-liquid contact efficiency improves. Since this gas-liquid mixed fluid has a low apparent density, it is inherently difficult to reach the deep part as the gas mixing ratio increases. However, when passing through the ascending pipe (14), since the density is lower than the water in the storage tank (1), a rising force is generated, so that the mixed fluid can reach a deep position. In addition, the mixed fluid that has become supersaturated due to the water pressure effect generates fine bubbles when the pressure is returned to normal pressure, and the separation time becomes longer, making it difficult to increase volumetric efficiency. However, since the water pressure decreases as the water rises in the ascending pipeline (14), the bubble diameter increases, and as the bubble diameter increases, the rising speed increases. Liquid separation can be performed at high speed. Therefore, the storage tank has a capacity of 350 L, about 200 L is water, and 150 L is a gas phase, and one circulation is about 10 seconds when the circulation amount is 60 m 3 / h.

図1bは、前記の構成と大きな変化は無いが、自由落下部(11)の下部は狭窄部(12)を経由して、下降管路(13a)に接続されており、上昇管路(14)は2重管路となり、スペース効率を高めている。狭窄部(12)は、 図1bの様にテーパー状に狭窄することが望ましく、 この部分の流速を3m/s程度まで上昇させると、2mm以上の大きな気泡も下降流に流すことが可能となる。その為、ガスの取り込み量が増加し、接触効率と容積効率の向上が可能となる。   In FIG. 1 b, there is no significant change from the above-described configuration, but the lower part of the free fall part (11) is connected to the descending pipe line (13 a) via the narrowed part (12), and the ascending pipe line (14 ) Is a double pipe line, improving space efficiency. The constricted portion (12) is desirably constricted in a tapered shape as shown in FIG. 1b. When the flow velocity in this portion is increased to about 3 m / s, a large bubble of 2 mm or more can also flow in the downward flow. . As a result, the amount of gas taken up increases, and contact efficiency and volumetric efficiency can be improved.

図1cは、図1aと同等の構成であるが、水循環管路(5)の最上部の水平管上にアスピレーター(23)を備えて、水循環管路2次側(5a)を経由して、気液接触塔(10)に接続されている。水循環管路(5)の最上部では、水頭圧がゼロに近いため、アスピレーター(23)の流速が低くても、気体を吸引して気液接触塔(10)に気体を供給することが可能である。自由落下部(11)に到達後は図1aと同等の作用により、気液混合を行うことができる。水循環管路2次側(5a)の配管口径は、気体も含む為太い口径が望ましく、図1cの様に自由落下部(11)と同一口径として、上部にスクリーン(10a)等を設置して、壁面を伝わる水量を減少させる方が、衝突面(18)でのガスの巻き込み量が増加する。尚、水循環管路(5)の経路上では、適宜アスピレーターを設置して、気体の吸引を行い気液接触塔(10)へ気体を供給することは可能である。気体混合部から自由落下部(11)までの距離を長くすることで、自由落下部(11)以前にも気液接触が行えることから、容積効率を向上させる効果が期待できる。しかし、この場合には液体移送手段(4)の出口側の水頭圧の加わる部位では、水頭圧を相殺する以上の流速が必要になることから、動力コストが増加することになる。液体移送手段(4)の一次側では、液体移送手段(4)が気液混合流体を移送することになる為、キャビテーションやウォーターハンマー等が生じ易く故障の原因となったり、液体移送効率が低下することを考慮する必要がある。   FIG. 1c is the same configuration as FIG. 1a, but with an aspirator (23) on the top horizontal pipe of the water circulation line (5), via the water circulation line secondary side (5a), It is connected to the gas-liquid contact tower (10). At the top of the water circulation line (5), the water head pressure is close to zero, so even if the flow rate of the aspirator (23) is low, the gas can be sucked and supplied to the gas-liquid contact tower (10). It is. After reaching the free fall portion (11), gas-liquid mixing can be performed by the same action as in FIG. 1a. The pipe diameter on the secondary side of the water circulation pipe (5a) is preferably a large diameter because it contains gas, and has the same diameter as the free fall part (11) as shown in FIG. When the amount of water transmitted through the wall surface is reduced, the amount of gas entrained at the collision surface (18) increases. In addition, on the path | route of a water circulation line (5), it is possible to install an aspirator suitably and to attract | suck gas and to supply gas to a gas-liquid contact tower (10). By increasing the distance from the gas mixing part to the free fall part (11), gas-liquid contact can be performed before the free fall part (11), and therefore the effect of improving volumetric efficiency can be expected. However, in this case, at the portion where the head pressure is applied on the outlet side of the liquid transfer means (4), a flow rate higher than the head pressure is required, which increases the power cost. On the primary side of the liquid transfer means (4), since the liquid transfer means (4) transfers the gas-liquid mixed fluid, cavitation, water hammer, etc. are likely to occur and cause failure or decrease in liquid transfer efficiency. It is necessary to consider what to do.

〔実施形態3〕
以下、本発明の第3実施形態を図面に基づいて説明する。
図2は、図1bの構成を更に気体吸引量を増加させ、処理効率を高める気液接触機構の一例である。他の構成は、図1bと同様であるが、ガス循環管路(15)に接続されているガス供給管路は、本図では省略している。また、気液接触塔(10)と貯留槽喫水面(19)との位置関係のみを示している。自由落下部(11)にガス循環管路(15) が接続されているが、 水循環管路(5)からの水流が自由落下部(11)に落下する直下に、下側に開口している。本実施形態によると、内径200mmの自由落下部(11)に、自由落下水の下流側に開口部を持つL字管を設けている。この様な、構成とすると、水の粘性と表面張力により開口部付近が水流に覆われ、その水流の中心部にはチューブ状の空間が形成される。L字管の上面が、自由落下水の障害物となることから、その下流ではカルマン渦が発生し、チューブ状の空間の気泡をちぎる様に閉じ込めながら、衝突面/下流側水面(18)に落下するので、気泡の発生量が増大する。実施形態2と同等の条件で水循環を行うと、18Nm/h程度のガスを吸引することが可能となり、循環水量に対して30%の吸引量となり、処理効率を向上させることができる。
[Embodiment 3]
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.
FIG. 2 is an example of a gas-liquid contact mechanism that further increases the gas suction amount and increases the processing efficiency of the configuration of FIG. 1B. The other configuration is the same as that of FIG. 1b, but the gas supply line connected to the gas circulation line (15) is omitted in the figure. Moreover, only the positional relationship between the gas-liquid contact tower (10) and the storage tank draft surface (19) is shown. The gas circulation line (15) is connected to the free fall part (11), but the water flow from the water circulation line (5) opens to the lower side just below the free fall part (11). . According to this embodiment, an L-shaped tube having an opening on the downstream side of the free fall water is provided in the free fall portion (11) having an inner diameter of 200 mm. With such a configuration, the vicinity of the opening is covered with a water flow due to the viscosity and surface tension of water, and a tubular space is formed at the center of the water flow. Since the upper surface of the L-shaped tube becomes an obstacle to free-fall water, Karman vortices are generated downstream of the L-shaped tube, confining the air bubbles in the tube-like space so as to break off, and colliding with the collision surface / downstream water surface (18). Since it falls, the amount of bubbles generated increases. When water circulation is performed under the same conditions as in the second embodiment, a gas of about 18 Nm 3 / h can be sucked, and the suction amount is 30% with respect to the circulating water amount, so that the processing efficiency can be improved.

〔実施形態4〕
以下、本発明の第4実施形態を図面に基づいて説明する。
図3aは、蒸気インゼクター(40)を用いた気液接触機構の一例である。貯留槽(1)、液体移送手段(4)等は図1a、図1b等とほぼ同様な為、異なる構成部分の説明を行う。ガス循環管路(15)は蒸気インゼクター吸い込み口(43)と接続されており、その経路の途中にガス供給管路(16)も接続されている。蒸気入口(41)から蒸気が供給されると、蒸気インゼクター吸い込み口は負圧となり、蒸気30kg/h使用時に24Nm/hのガスを吸引する。蒸気インゼクター出口(42)に排気された水蒸気とガスは自由落下部(11)に放出される。この時に水蒸気は自由落下する水と接触し、体積を失うので蒸気インゼクター出口管内は低圧となり、吸引効率が極めて高い。一方自由落下部(11)に入ったガスは、 強制供給されている為、 衝突面/下流側水面(18)付近のガス圧は、実施形態1〜3に比べて高くなる。しかし、ガス圧が上昇すると衝突面/下流側水面の位置を下げることになる為、打撃力が大きくなることと、ガス体積が減少することや溶け込み量が増加し、一定のガス圧に上昇した所でバランスする。尚、ガスの強制供給を行うと、前述の様に自由落下の距離に余裕ができる。その為、処理効率をより高める為に、接触管路(13)内に静止型ミキサー(44)の様に、流速により積極的な攪拌を行う機能を追加することも有効である。即ち、この様な静止型の攪拌器は圧力損失を生じることから、衝突面の水位を上昇させる作用を持つ。その一方で蒸気インゼクター(40)を利用すると、自由落下部の内圧が上昇するので、衝突面を下げる作用を持つ為である。その為、自由落下部の高さを変更すること無く、この様な攪拌機能を追加することが可能となる。この様な構成を取ると、実施形態1の条件で、 ガスを24Nm/h供給することができることと、蒸気の凝縮効果により処理効率が極めて良好となり、60t/hの循環量に対して、30t/h以上の処理水量を得ることができる。
[Embodiment 4]
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 3a is an example of a gas-liquid contact mechanism using a steam injector (40). Since the storage tank (1), the liquid transfer means (4) and the like are substantially the same as those shown in FIGS. 1a and 1b, different components will be described. The gas circulation line (15) is connected to the steam injector suction port (43), and the gas supply line (16) is also connected in the middle of the path. When steam is supplied from the steam inlet (41), the steam injector suction port becomes negative pressure, and sucks 24 Nm 3 / h of gas when using steam of 30 kg / h. Water vapor and gas exhausted to the steam injector outlet (42) are released to the free fall part (11). At this time, water vapor comes into contact with free-falling water and loses its volume, so the pressure inside the steam injector outlet pipe is low, and the suction efficiency is extremely high. On the other hand, since the gas that has entered the free fall portion (11) is forcibly supplied, the gas pressure in the vicinity of the collision surface / downstream water surface (18) is higher than in the first to third embodiments. However, if the gas pressure rises, the position of the collision surface / downstream water surface will be lowered, so the impact force will increase, the gas volume will decrease, the amount of penetration will increase, and it will rise to a certain gas pressure Balance in place. If the gas is forcibly supplied, a free fall distance can be provided as described above. Therefore, in order to further increase the processing efficiency, it is also effective to add a function of performing agitation at a flow rate, such as a static mixer (44), in the contact line (13). That is, since such a static stirrer causes a pressure loss, it has the effect of raising the water level on the collision surface. On the other hand, when the steam injector (40) is used, the internal pressure of the free fall portion is increased, so that the collision surface is lowered. Therefore, it is possible to add such a stirring function without changing the height of the free fall part. When such a configuration is adopted, the gas can be supplied at 24 Nm 3 / h under the conditions of the first embodiment, and the processing efficiency becomes extremely good due to the condensation effect of the vapor. For the circulation amount of 60 t / h, A treated water amount of 30 t / h or more can be obtained.

図3bの様に蒸気インゼクターの代わりに、送風機(50)を用いても、蒸気の凝縮効果を除けば、ガス量を上昇させることができるので、処理効率の向上を期待できる。自由落下を利用した気液接触法においては、元々ガス注入点の圧力が低い為、使用する気体移送手段は、1KPa程度の静圧で十分であるので、 送風機の様な低圧大流量特性が適しているが、コンプレッサーや真空ポンプの様に容積式の気体移送手段を、処理水量に応じて回転数制御を行う等の方法で、動力費と処理効率のバランスを適正化することも可能である。   Even if a blower (50) is used instead of the steam injector as shown in FIG. 3B, the gas amount can be increased except for the condensation effect of the steam, so that an improvement in processing efficiency can be expected. In the gas-liquid contact method using free fall, since the pressure of the gas injection point is originally low, a static pressure of about 1 KPa is sufficient for the gas transfer means to be used, so low pressure and large flow characteristics like a blower are suitable. However, it is also possible to optimize the balance between the power cost and the processing efficiency by a method such as controlling the number of revolutions of a positive displacement gas transfer means like a compressor or a vacuum pump according to the amount of treated water. .

〔実施形態5〕
以下、本発明の第5実施形態を図面に基づいて説明する。
図4は、自由落下を利用した4段式の窒素置換脱酸素装置の実施の一例である。この図4では、4段となっているが、一段目気液接触機構(6a)〜四段目気液接触機構(6d)は、その構成要素が図1bとほぼ同一の為、三段目気液接触機構(6c)にのみ各構成要素の記号を付記し、他の接触機構については同一の構成要素に関しては記号を省略している。各気液接触機構は、液体移送手段(4)により循環を行っており、水の流通が無い場合には、各貯留槽(1)の水とガスを循環している状態でバランスしている。
原水は、調整水槽(20)に装置水入口(7a)から給水される。調整水槽(20)は、図では省略してあるが、フロート或いは電極等の水位検出器と制御弁により電気的なレベルコントロールを行う機能か、ボールタップの様に機械的に水位調整を行う水位調整機能を有している。ボイラ等が給水を必要とする場合には、装置水出口(8a)からの処理水を供給する。処理水出口から処理水が供給されると、四段目気液接触機構(6d)の貯留槽の水位が低下し、三段目気液接触機構(6c)の貯留槽水位が四段目より高くなる為、三段目気液接触機構(6c)からの処理水が流入する。その様な構成を取りながら、調整水槽(20)の水位が低下する為、調整水槽(20)の水位コントロールのみで、適正水位を保つことができる。調整水槽(20)の水位コントロール弁の開閉信号や装置水入口部の原水流量信号等の流量信号に応じて、窒素ガスが装置ガス供給管路(16a)を通じて供給されると、四段目気液接触機構(6d)の貯留槽(1)内の循環ガスと伴に自由落下部(11)を経由して、ガス交換を行い貯留槽(1)内の気室に供給される。
[Embodiment 5]
Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings.
FIG. 4 is an example of an implementation of a four-stage nitrogen substitution deoxygenation device using free fall. In FIG. 4, there are four stages, but the first-stage gas-liquid contact mechanism (6a) to fourth-stage gas-liquid contact mechanism (6d) are substantially the same as those in FIG. Only the gas-liquid contact mechanism (6c) is provided with symbols of each component, and the symbols of the other contact mechanisms are omitted for the same components. Each gas-liquid contact mechanism is circulated by the liquid transfer means (4), and when there is no circulation of water, the water and gas in each storage tank (1) are circulated and balanced. .
The raw water is supplied to the adjusted water tank (20) from the apparatus water inlet (7a). Although the adjustment water tank (20) is omitted in the figure, it is a function of performing electric level control by a water level detector such as a float or an electrode and a control valve, or a water level adjustment that performs water level adjustment mechanically like a ball tap. It has a function. When the boiler or the like needs water supply, treated water is supplied from the apparatus water outlet (8a). When treated water is supplied from the treated water outlet, the water level in the storage tank of the fourth-stage gas-liquid contact mechanism (6d) decreases, and the storage tank water level of the third-stage gas-liquid contact mechanism (6c) starts from the fourth stage. Since it becomes high, the treated water flows from the third stage gas-liquid contact mechanism (6c). Since the water level of the adjustment water tank (20) falls while taking such a structure, an appropriate water level can be maintained only by controlling the water level of the adjustment water tank (20). When nitrogen gas is supplied through the apparatus gas supply line (16a) in response to a flow signal such as an open / close signal of the water level control valve of the adjustment water tank (20) or a raw water flow signal of the apparatus water inlet, Gas exchange is performed via the free fall part (11) together with the circulating gas in the storage tank (1) of the liquid contact mechanism (6d), and the gas is supplied to the air chamber in the storage tank (1).

本実施形態においては、全てのタンクの水のラインは接続されている為、水位を一定に保とうとするので、四段目の貯留槽(1)内の気圧が、三段目の貯留槽(1)内の気圧より高くなるので流入ガスと見合った量の循環ガス量が三段目の貯留槽(1)に供給される。循環を行いながら純度の低下したガスは最終的に装置ガス排気管路(17a)から外部に排気されるが、給水供給量が少ない時は、比例して排気されるガス量も少なくなる為、僅かな水位の変動でも外気を一段目気液接触機構(6a)の気室に吸込んでしまうこととなる。これを防止する為に、水封水槽(21)を設けている。装置ガス排気管路(17a)からのガスは、水封水槽(21)の水封部を経由してガス排気口(22)から外気に放出される。因みに、調整水槽(20)の水位が低下した場合には、装置ガス排気管路内は負圧となるが、水封高さまでは外気の浸入を阻止する様になっている。但し、調整水槽(20)の水位が、原水の不足や水位コントロール等の不具合で、極端な低水位状態となった場合には、水封を破り外気が貯留槽(1)内に流入することで、タンクの負圧が過大になることが防止できる。   In this embodiment, since the water lines of all the tanks are connected, the water level is kept constant, so that the atmospheric pressure in the fourth-stage storage tank (1) is changed to the third-stage storage tank ( 1) Since it becomes higher than the atmospheric pressure in the inside, the amount of circulating gas corresponding to the inflow gas is supplied to the third-stage storage tank (1). The gas whose purity is lowered while circulating is finally exhausted from the apparatus gas exhaust pipe (17a), but when the amount of water supply is small, the amount of gas exhausted proportionally decreases. Even a slight fluctuation in water level will cause outside air to be sucked into the air chamber of the first-stage gas-liquid contact mechanism (6a). In order to prevent this, a water-sealed water tank (21) is provided. The gas from the apparatus gas exhaust pipe (17a) is discharged from the gas exhaust port (22) to the outside air through the water seal portion of the water seal water tank (21). Incidentally, when the water level of the adjustment water tank (20) decreases, the apparatus gas exhaust pipe has a negative pressure, but the water seal height prevents the intrusion of outside air. However, if the water level in the adjustment water tank (20) becomes extremely low due to a lack of raw water or water level control, the water seal is broken and the outside air flows into the storage tank (1). Therefore, it can be prevented that the negative pressure of the tank becomes excessive.

本実施形態では、液体移送手段(4)としての水循環ポンプは、装置の定格能力20t/hの3倍の60t/hの流量を選定している。貯留槽(1)の水面から水循環管路(5)頂部の高さは約1mの為、出口流速や配管の圧力損失を含めてもポンプの必要揚程は2mでポンプ効率50%で0.75kw程度の出力である。20t/hの定格能力に対して、60t/hの水循環量は多い様に考えるかも知れないが、順流式では1回で処理を完結しようとするとエネルギーや設備容積面からも不利である為、標準では3循環で完結できる設計としてある。そして、60t/hの水循環量を採用しているにはもうひとつの理由がある。処理水である脱酸素水は、空気に触れると純度が低下する為、オンデマンドで供給することが望ましい。しかし、ボイラ等はある一定時間における給水量の最大値はボイラの定格能力で決定されるが、瞬間的にはボイラの定格能力の1.5倍程の給水が行われる。オンデマンドで脱酸素水を供給する場合、循環ポンプの循環量がこの瞬間的な給水量を下回ってしまうと、未処理の水がショートパスしてしまうか、処理水が不足する等の不具合を生じてしまう。   In this embodiment, the water circulation pump as the liquid transfer means (4) selects a flow rate of 60 t / h, which is three times the rated capacity of the device 20 t / h. Since the height of the top of the water circulation pipe (5) from the water surface of the storage tank (1) is about 1m, the required head of the pump is 2m and the pump efficiency is 0.75kw with 50% pump efficiency, including the outlet flow velocity and piping pressure loss. It is about the output. You may think that the water circulation rate of 60 t / h is large for the rated capacity of 20 t / h, but in the forward flow type, if you try to complete the treatment once, it is disadvantageous from the aspect of energy and equipment capacity, The standard is designed to be completed in three cycles. And there is another reason for adopting a water circulation rate of 60 t / h. It is desirable to supply deoxygenated water, which is treated water, on demand because the purity decreases when it comes into contact with air. However, although the maximum value of the water supply amount in a certain period of time is determined by the rated capacity of the boiler, the water supply is about 1.5 times the rated capacity of the boiler instantaneously. When supplying deoxygenated water on demand, if the circulation rate of the circulation pump falls below this momentary water supply rate, problems such as short-circuiting of untreated water or shortage of treated water will occur. It will occur.

本実施形態では、隔壁(9)を水入口部に設置することで、例えば30t/hの流量で数秒間過大流量が流れても、液体移送手段の流量は60t/hである為、装置水入口(7a)からの水は全て液体移送手段に流れ込み、残りの30t/hを隔壁の右側開口部から貯留槽内の処理済の水が液体移送手段に供給することになるので、ショートパスにより上流側の水が直接下流側に流れることが無いので過大流量に対応できる。即ち数秒間の過大流量の後には、必ず定格能力より少ない流量が現れるので、過大流量時の処理性能ではなく、定格運転時の処理性能に合わせて設計することができるので、コストダウンや容積効率の向上に有利であるからである。
尚、この構成に、実施形態3における気体吸引力を高める技術や、蒸気インゼクターを併用することで、装置の大きさを変えずに連続定格時の処理能力を高めることができる。気体吸引力を高める方法では、25t/hの連続処理能力まで、蒸気を併用した場合には30t/hの連続処理能力まで対応が可能である。更に、蒸気インゼクターの能力を増し、接触管路(13)に静止型ミキサー等の混合促進機能を負荷することにより、45t/h程度まで供給能力を上げることも可能であり、過大流量を生じないプラント向けには有利である。尚、ボイラ用途等で後段にて更に加熱が必要な用途においては、蒸気を使用しても、その熱量は全て回収できるので、動力の無駄にならない点も有利である。因みに、 本実施形態における処理効率は 図5の通りである。 負荷が20t/hまでは蒸気を使用しなくても、ほぼ理論値通りの処理が可能であるので、ボイラ等の立ち上げ時等でも、運用に問題は無い。
尚、オンデマンド型の処理水供給方法の窒素使用率の低減効果は図6で確認できる。本方式では窒素の使用率は全負荷において30〜40NL/t前後で安定しているが、対向流型の処理方法の場合には、定量の処理水を流し続ける必要がある為、負荷が低い時には原水1t当たりの窒素使用量が極めて大きく、非効率であることが判る。
又、蒸気インゼクターや気体移送手段により、強制通気を行う場合、要求される処理水量を検出し、例えば平均処理水量が20t/h以下の場合には、強制換気を行わず、20t/h以上になった場合に、強制換気を行う運用を行うことにより、動力コストを削減しながら容積効率を高めることが可能となる。
In the present embodiment, by installing the partition wall (9) at the water inlet, even if an excessive flow rate flows for several seconds at a flow rate of 30 t / h, for example, the flow rate of the liquid transfer means is 60 t / h. All the water from the inlet (7a) flows into the liquid transfer means, and the remaining 30 t / h is supplied to the liquid transfer means by the treated water in the storage tank from the right side opening of the partition wall. Since the upstream water does not flow directly downstream, it can cope with an excessive flow rate. In other words, a flow rate that is less than the rated capacity always appears after an excessive flow rate for several seconds, so it can be designed according to the processing performance at the rated operation, not the processing performance at the excessive flow rate. It is because it is advantageous for improvement.
In addition, by using the technology for increasing the gas suction force in Embodiment 3 and the steam injector in this configuration, the processing capacity at the time of continuous rating can be increased without changing the size of the apparatus. In the method of increasing the gas suction force, it is possible to cope with a continuous processing capacity of 25 t / h, and when steam is used in combination, a continuous processing capacity of 30 t / h can be handled. Furthermore, it is possible to increase the supply capacity up to about 45t / h by increasing the capacity of the steam injector and loading the contact line (13) with a mixing promotion function such as a static mixer, resulting in an excessive flow rate. This is advantageous for plants that do not. In addition, in an application that requires further heating at a later stage, such as a boiler application, even if steam is used, all of its heat can be recovered, so that power is not wasted. Incidentally, the processing efficiency in this embodiment is as FIG. Even when steam is not used up to a load of 20 t / h, processing can be performed almost as theoretically, so there is no problem in operation even when a boiler or the like is started up.
In addition, the reduction effect of the nitrogen usage rate of the on-demand type treated water supply method can be confirmed in FIG. In this method, the nitrogen usage rate is stable at around 30 to 40 NL / t at the full load, but in the case of the counter-flow type treatment method, it is necessary to keep a constant amount of treated water flowing, so the load is low. It can sometimes be seen that the amount of nitrogen used per ton of raw water is extremely large and inefficient.
Further, when forced ventilation is performed by a steam injector or a gas transfer means, the required amount of treated water is detected. For example, when the average treated water amount is 20 t / h or less, forced ventilation is not performed, and 20 t / h or more is not performed. In such a case, it is possible to increase the volumetric efficiency while reducing the power cost by performing the operation of performing the forced ventilation.

〔脱酸素水の利用用途〕
本発明により供給される脱酸素水は、ボイラ等への補給水とすることで、ボイラの腐食を防止することができる。特に、本発明による気液接触装置は、処理効率や容積効率が高く、エネルギー使用率も優れていることや、オンデマンド型の処理水供給方法が可能な為、窒素使用率を大幅に低減できるので、窒素ボンベや液体窒素等の購入窒素を利用する場合でも、低コストである。そのため、窒素発生器やコンプレッサー等のイニシャルコストが削減でき、利用用途の更なる拡大が見込まれる。
[Use of deoxygenated water]
The deoxygenated water supplied by the present invention can be used as make-up water for a boiler or the like, thereby preventing corrosion of the boiler. In particular, the gas-liquid contact device according to the present invention has a high processing efficiency and volumetric efficiency, an excellent energy usage rate, and an on-demand type treatment water supply method, which can greatly reduce the nitrogen usage rate. Therefore, even when using purchased nitrogen such as a nitrogen cylinder or liquid nitrogen, the cost is low. For this reason, the initial cost of a nitrogen generator, a compressor, etc. can be reduced, and further expansion of usage is expected.

〔気液接触装置としての利用用途〕
本発明による自由落下部を用いた気液接触方法は、極めてシンプルで低動力である為、従来水中に空気を吹き込むことで実現されていた廃水や湖沼等の曝気処理の用途にも応用が可能であると考える。
[Use as gas-liquid contact device]
The gas-liquid contact method using a free fall part according to the present invention is extremely simple and has low power, so it can be applied to the use of aeration treatment such as waste water and lakes that have been realized by blowing air into the water. I believe that.

1…貯留槽
2…貯留槽水側
3…貯留槽気室側
4…液体移送手段
5…水循環管路
5a…水循環管路2次側
6…気液接触機構
6a…一段目気液接触機構
6b…二段目気液接触機構
6c…三段目気液接触機構
6d…四段目気液接触機構
7…水入口
7a…装置水入口
8…水出口
8a…装置水出口
9…隔壁
10…気液接触塔
10a…スクリーン
11…自由落下部
12…狭窄部
13…接触管路
13a…下降管路
14…上昇管路
15…ガス循環管路
16…ガス供給管路
16a…装置ガス供給管路
17…排気管路
17a…装置ガス排気管路
18…衝突面・下流側水面
19…貯留槽喫水面
20…調整水槽
21…水封水槽
22…ガス排気口
23…アスピレーター
30…貯留槽上面
31…貯留槽底面
40…蒸気インゼクター
41…蒸気入口
42…蒸気インゼクター出口
43…蒸気インゼクター吸い込み口
44…静止型ミキサー
50…送風機
DESCRIPTION OF SYMBOLS 1 ... Storage tank 2 ... Storage tank water side 3 ... Storage tank air chamber side 4 ... Liquid transfer means 5 ... Water circulation pipeline 5a ... Water circulation pipeline secondary side 6 ... Gas-liquid contact mechanism 6a ... First-stage gas-liquid contact mechanism 6b 2nd stage gas-liquid contact mechanism 6c 3rd stage gas-liquid contact mechanism 6d 4th stage gas-liquid contact mechanism 7 ... Water inlet 7a ... Device water inlet 8 ... Water outlet 8a ... Device water outlet 9 ... Bulkhead 10 ... Gas Liquid contact tower 10a ... Screen 11 ... Free fall part 12 ... Constriction part 13 ... Contact line 13a ... Down line 14 ... Up line 15 ... Gas circulation line 16 ... Gas supply line 16a ... Device gas supply line 17 ... Exhaust pipe 17a ... System gas exhaust pipe 18 ... Collision surface / downstream water surface 19 ... Storage tank draft surface 20 ... Adjusted water tank 21 ... Water-sealed water tank 22 ... Gas exhaust port 23 ... Aspirator 30 ... Storage tank upper surface 31 ... Storage Tank bottom 40 ... Steam injector 41 ... Steam inlet 42 ... Steam injector outlet 43 ... Steam injector suction port 44 ... Static mixer 50 ... Blower

Claims (5)

処理水と対象ガスを混合循環しながら、その一部を処理済み水及び処理済みガスとして系外に排出し、バランスした量の処理前水と処理前ガスを流入させる循環型の気液接触方法であって、
対象ガスが大気では無い場合には密閉構造を持ち、貯留部および気相部を備える貯留槽と、
対象ガスが大気では無い場合には密閉構造を持ち、上部に給水口、下部に排水口および気室部を備える気液接触塔と、
前記貯留槽と前記給水口とを接続する循環管路と、
前記貯留槽と前記排水口とを接続する接触管路と、
前記貯留槽と前記気液接触塔との間の液体を循環する液体移送手段と、を備え、
前記貯留槽の気相部と、前記気液接触塔の気室部とは、対象ガスが大気では無い場合にはガス循環管路により連通され、
前記接触管路の断面積は、前記貯留槽の喫水面と、前記接触管路の流速と圧力損失から決まる下流側水面が前記給水口より低くなり、且つ流速が0.15m/s以上5m/s未満となる値に設定され、
前記気液接触塔の水平方向の断面積は、循環する水量が、重力加速度に従って落下する時の流速に対応する断面積よりも大きく、下流側水面以降の下降流速が0.15m/s以上5m/s未満となる値に設定され、
前記気液接触塔の垂直方向の高さは、前記給水口から落下する自由落下水の下流側水面への衝突速度が0.5m/s以上となる値に設定される
ことを特徴とする気液接触方法。
A circulating gas-liquid contact method in which treated water and target gas are mixed and circulated while a part of the treated water and treated gas is discharged out of the system as treated water and treated gas, and a balanced amount of pre-treated water and pre-treated gas is introduced. Because
When the target gas is not air, it has a sealed structure, a storage tank having a storage part and a gas phase part,
A gas-liquid contact tower having a sealed structure when the target gas is not the atmosphere, having a water supply port at the top, a drain port and an air chamber at the bottom,
A circulation line connecting the storage tank and the water supply port;
A contact line connecting the storage tank and the drain port;
A liquid transfer means for circulating a liquid between the storage tank and the gas-liquid contact tower,
The gas phase part of the storage tank and the gas chamber part of the gas-liquid contact tower are communicated by a gas circulation line when the target gas is not the atmosphere,
The cross-sectional area of the contact pipe is such that the draft surface of the storage tank and the downstream water surface determined from the flow velocity and pressure loss of the contact pipe are lower than the water supply port, and the flow velocity is 0.15 m / s to 5 m / s. set to a value less than s ,
The horizontal cross-sectional area of the gas-liquid contact tower is larger than the cross-sectional area corresponding to the flow velocity when the circulating water falls according to the gravitational acceleration, and the descending flow velocity after the downstream water surface is 0.15 m / s or more and 5 m. Is set to a value that is less than / s ,
The vertical height of the gas-liquid contact tower is set to a value at which the collision speed of the free fall water falling from the water supply port to the downstream water surface is 0.5 m / s or more. Liquid contact method.
請求項1に記載の気液接触方法において、
前記接触管路が、前記貯留槽の底面よりも下部に延長した下降管路と、前記貯留槽内に開口部を持つ上昇管路とを備える
ことを特徴とする気液接触方法。
The gas-liquid contact method according to claim 1,
The gas-liquid contact method, wherein the contact pipe includes a descending pipe extending downward from a bottom surface of the storage tank, and a rising pipe having an opening in the storage tank.
請求項1または請求項2に記載の気液接触方法において、
前記気液接触塔が、前記気室部を流下する液体流中に液体流の一部の速度を低下させる
障害手段と、その下流側に前記ガス循環管路またはガス供給管路の開口部とを備える
ことを特徴とする気液接触方法。
In the gas-liquid contact method according to claim 1 or 2,
The gas-liquid contact tower is configured to obstruct means for reducing the speed of a part of the liquid flow in the liquid flow flowing down the gas chamber, and an opening of the gas circulation pipe or the gas supply pipe on the downstream side thereof. A gas-liquid contact method characterized by comprising:
請求項1から請求項3のいずれか一項に記載の気液接触方法において、
前記ガス循環管路の経路上に、気体移送手段を備える
ことを特徴とする気液接触方法。
In the gas-liquid contact method according to any one of claims 1 to 3,
A gas-liquid contact method characterized by comprising gas transfer means on the path of the gas circulation line.
請求項1から請求項4のいずれか一項に記載の気液接触方法において、
前記対象ガスとして不活性ガスを用い、前記処理水中のガス組成を前記不活性ガスのガス組成に置換させる
ことを特徴とする水の脱酸素方法。
In the gas-liquid contact method according to any one of claims 1 to 4,
An inert gas is used as the target gas, and the gas composition in the treated water is replaced with the gas composition of the inert gas.
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