JP3271744B2 - Desalting method using electrodialysis equipment - Google Patents
Desalting method using electrodialysis equipmentInfo
- Publication number
- JP3271744B2 JP3271744B2 JP23893496A JP23893496A JP3271744B2 JP 3271744 B2 JP3271744 B2 JP 3271744B2 JP 23893496 A JP23893496 A JP 23893496A JP 23893496 A JP23893496 A JP 23893496A JP 3271744 B2 JP3271744 B2 JP 3271744B2
- Authority
- JP
- Japan
- Prior art keywords
- water
- chamber
- seawater
- treated
- desalination
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
Description
【０００１】[0001]
【発明の属する技術分野】本発明は電気透析装置による
脱塩方法に係り、特に、臨海地域に立地している火力発
電所や工場の工場排水、例えば排煙脱硫排水等の脱塩を
行い工業用水として再利用を図るための電気透析装置に
よる脱塩方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a desalination method using an electrodialysis apparatus, and more particularly to desalination of industrial wastewater from a thermal power plant or a factory located in a seaside area, for example, flue gas desulfurization wastewater. The present invention relates to a desalination method using an electrodialysis device for reusing water for use.
【０００２】[0002]
【従来の技術】各種の工場では、工業用水の使用量の節
減を図るために、工場排水（以下、排水という）の回収
・再利用化の検討が行われている。一般的に、排水の汚
染度が低く、且つ排水中に含有される塩類濃度が５００
ｍｇ／ｌ程度以下の場合には、排水を回収系排水或いは
低塩系排水として分別回収し、そのままか或いは除濁処
理程度の簡単な排水処理を行って再利用している。2. Description of the Related Art Various factories are studying the collection and reuse of factory wastewater (hereinafter referred to as wastewater) in order to reduce the amount of industrial water used. Generally, the pollution degree of wastewater is low and the concentration of salts contained in the wastewater is 500
When the amount is less than about mg / l, the wastewater is separated and collected as a collection wastewater or a low-salt wastewater and reused as it is or after performing a simple wastewater treatment such as a turbidity treatment.
【０００３】しかし、排水の汚染度が高く、且つ排水中
に含有される塩類濃度が５００ｍｇ／ｌ程度以上の場合
には、排水を非回収系排水或いは高塩系排水として分別
回収し、総理府令で定められた排水基準、都道府県条例
で定める排水基準、更には地元協定値を遵守するように
排水処理を行ってから、河川、海域等に放流している。[0003] However, when the degree of pollution of the wastewater is high and the concentration of salts contained in the wastewater is about 500 mg / l or more, the wastewater is separated and recovered as non-collection wastewater or high-salt wastewater. The wastewater is treated so as to comply with the wastewater standards set forth in, the prefectural ordinances, and even the local agreement, before being released into rivers and seas.
【０００４】非回収系排水の放流量は工場によって異な
るが、例えば工場排水の発生量が大きい火力発電所の場
合でみると、発電規模や燃料の種類により異なるものの
概ね日水量数１００〜５０００ｍ3 程度である。放流水
の水質は、無機系塩類（ＮａＣｌ、Ｎａ2 ＳＯ4 、Ｃａ
Ｃｌ2 、ＣａＳＯ4 他、Ｍｇ化合物等）が主成分であ
り、有機系成分は殆ど含有されていない。そして、排水
中の総塩類濃度は、略２０００〜５０００ｍｇ／ｌであ
る。回収されて再利用される回収系排水量は、回収系、
非回収系を合わせた総排水量の１０〜２０％にすぎず、
大部分は非回収系排水であり、回収・再利用率は極めて
低いのが現状である。[0004] The discharge rate of non-recovery system wastewater varies from factory to factory. For example, in the case of a thermal power plant in which the amount of factory wastewater generated is large, it differs depending on the power generation scale and the type of fuel, but is generally about 100 to 5000 m 3 per day. It is about. The quality of the effluent is determined by inorganic salts (NaCl, Na 2 SO 4 , Ca
Cl 2, CaSO 4 other, a Mg compound, etc.) is the main component, an organic component is not contained little. And the total salt concentration in the waste water is approximately 2000 to 5000 mg / l. The amount of wastewater collected and reused in the collection system is
It is only 10-20% of the total drainage combined with non-recovery system,
Most of the wastewater is non-collection wastewater, and the recovery / reuse rate is extremely low.
【０００５】このような背景から、非回収系排水の回収
・再利用化率を高める検討が行われているが、再利用す
るには放流水並みの水質に加えて工業用水並みの塩類濃
度、具体的には５００ｍｇ／ｌ程度以下を確保すること
が必要条件であり、脱塩処理を必要とする。また、排水
からの脱塩処理に係わらず、例えば、塩類を含有する地
下水等を向上用水として使用する場合にも脱塩処理を必
要とする。[0005] Against this background, studies have been made to increase the rate of recovery and reuse of non-recovery wastewater. However, in order to reuse the wastewater, in addition to the water quality equivalent to the effluent water, the salt concentration and the industrial water level are reduced. Specifically, it is a necessary condition to secure about 500 mg / l or less, and desalting treatment is required. In addition, regardless of the desalination treatment from wastewater, desalination treatment is also required when, for example, groundwater containing salts is used as improvement water.
【０００６】脱塩処理の方法としては、蒸発法、逆浸透
膜法、電気透析法、及びイオン交換法があるが、塩類濃
度が小さい場合には、蒸発法は大きなエネルギーを要す
ることから逆浸透膜法、電気透析法、及びイオン交換法
がコスト的に有利である。なかでも電気透析法は物質移
動量が小さくエネルギー的に有利なことから注目されて
いる。[0006] Desalination methods include an evaporation method, a reverse osmosis membrane method, an electrodialysis method, and an ion exchange method. When the salt concentration is low, the evaporation method requires a large amount of energy, so that the reverse osmosis method is used. The membrane method, the electrodialysis method, and the ion exchange method are advantageous in cost. Among them, the electrodialysis method has attracted attention because it has a small mass transfer amount and is advantageous in terms of energy.
【０００７】図５は、従来の電気透析装置１による脱塩
方法を示したもので、被処理水である排水は濾過装置２
で濾過されが後、脱塩水槽３に送水され、脱塩水槽３か
らイオン交換膜で区画形成される脱塩室４と濃縮室５と
に分配供給され、電圧が印加されることによりイオン状
の溶解塩類を脱塩室４側から濃縮室５側に透析（移動）
させる。これにより、脱塩室４には脱塩された脱塩水が
生成され、濃縮室５には塩類が濃縮された濃縮水が生成
される。そして、脱塩室４で生成された塩類濃度の低下
した脱塩水を回収することにより工業用水として再利用
することができる。一方、濃縮室５で濃縮された濃縮水
は濃縮水槽６を介して排水処理装置７へ送られ、濃縮さ
れて排水基準値をオーバーした排水規制成分を排水処理
により再度放流基準以下にしてから放流される。FIG. 5 shows a desalination method using a conventional electrodialysis apparatus 1.
After being filtered, the water is sent to the desalting water tank 3, and is distributed and supplied from the desalting water tank 3 to the desalting chamber 4 and the concentrating chamber 5 formed by the ion exchange membrane. Dialysis (transfer) of the dissolved salts from the desalting chamber 4 to the enrichment chamber 5
Let it. Thereby, desalted demineralized water is generated in the desalination chamber 4, and concentrated water in which salts are concentrated is generated in the concentration chamber 5. Then, by recovering the desalinated water having a reduced salt concentration generated in the desalination chamber 4, it can be reused as industrial water. On the other hand, the concentrated water concentrated in the concentration chamber 5 is sent to the wastewater treatment device 7 via the concentrated water tank 6, and the concentrated wastewater regulated component, which has exceeded the wastewater standard value, is again reduced to the discharge standard or less by the wastewater treatment, and then discharged. Is done.
【０００８】[0008]
【発明が解決しようとする課題】しかしながら、従来の
電気透析装置による脱塩方法には以下のような欠点があ
る。 被処理水、特に火力発電所において多量に発生する排
煙脱硫排水のように、ＣａＳＯ4 等のスケール成分が多
く含有されている場合には、濃縮室の濃縮倍率を上げす
ぎるとスケールが析出し、イオン交換膜にスケールが付
着して膜性能を低下させる。従って、このスケールトラ
ブルを回避するために、濃縮室側の塩類の濃縮倍率を低
く抑える必要があり、そのためには濃縮室側への排水の
供給量を多くする必要がある。その結果、相対的に脱塩
室側に供給される排水の供給量が少なくなるため、脱塩
水の回収率が低下し、通常は５０％以下の低回収率にな
ってしまうという欠点がある。However, the conventional desalting method using an electrodialysis apparatus has the following disadvantages. In the case where a large amount of scale components such as CaSO 4 is contained, such as flue gas desulfurization effluent generated in large amounts in treated water, particularly in thermal power plants, scale will precipitate if the concentration ratio of the concentration chamber is too high. In addition, the scale adheres to the ion exchange membrane and deteriorates the membrane performance. Therefore, in order to avoid this scale trouble, it is necessary to reduce the concentration ratio of the salts on the enrichment chamber side, and for that purpose, it is necessary to increase the amount of wastewater supplied to the enrichment chamber side. As a result, the supply amount of the wastewater supplied to the desalination chamber side is relatively reduced, so that the recovery rate of the desalinated water is reduced, and there is a disadvantage that the recovery rate is usually 50% or less.
【０００９】一方、濃縮室側への排水の供給量を多く
するために濃縮水の発生量が大きくなり、しかも濃縮水
中の排水規制成分濃度が大きすぎてそのままでは放流で
きないので、後工程で大量な濃縮水の排水処理が必要に
なる。この結果、排水処理費が嵩むという欠点がある。 電気透析における処理性能を高めるためには、電流密
度を限界電流密度以下の範囲で可能な限り大きくとるこ
とが好ましい。しかし、限界電流密度は塩類濃度に比例
し拡散層の厚みに反比例するので、拡散層の厚みが一定
の場合、被処理水である排水中の塩類濃度により左右さ
れてしまうという欠点ある。On the other hand, the amount of concentrated water generated is increased to increase the amount of wastewater supplied to the enrichment chamber, and the concentration of wastewater-regulating components in the concentrated water is too high to be discharged as it is, so that a large amount of wastewater is discharged in the subsequent process. Wastewater treatment of concentrated water is required. As a result, there is a drawback that the wastewater treatment cost increases. In order to enhance the processing performance in electrodialysis, it is preferable that the current density be as high as possible within the range of the limit current density or less. However, since the limiting current density is proportional to the salt concentration and inversely proportional to the thickness of the diffusion layer, there is a disadvantage that when the thickness of the diffusion layer is constant, it is influenced by the salt concentration in the wastewater as the water to be treated.
【００１０】本発明は、このような事情に鑑みてなされ
たもので、スケールトラブルを回避して脱塩水の回収率
を飛躍的に向上させることができるばかりでなく、限界
電流密度を大きくして電気透析の処理性能自体を高める
ことができる電気透析装置による脱塩方法を提供するこ
とを目的とする。The present invention has been made in view of such circumstances, and not only can the scale trouble be avoided and the recovery rate of desalinated water can be drastically improved, but also the critical current density can be increased. It is an object of the present invention to provide a desalination method using an electrodialysis apparatus that can enhance the processing performance itself of electrodialysis.
【００１１】[0011]
【課題を解決する為の手段】請求項１の発明は、前記目
的を達成する為に、陽イオン交換膜と陰イオン交換膜を
電極間に交互に配列して交互に脱塩室と濃縮室を形成す
る電気透析装置に海水以外の被処理水を供給して前記被
処理水中の塩類を脱塩する電気透析装置による脱塩方法
において、前記被処理水を前記脱塩室だけに通水すると
共に、前記濃縮室には海水を通水し、前記海水は、冷却
水として使用され自らは昇温された使用済の冷却水用海
水であり、この海水とは濃縮室に通水する海水であるこ
とを特徴とする。請求項２の発明は、前記目的を達成す
る為に、陽イオン交換膜と陰イオン交換膜を電極間に交
互に配列して交互に脱塩室と濃縮室を形成する電気透析
装置に海水以外の被処理水を供給して前記被処理水中の
塩類を脱塩する電気透析装置による脱塩方法において、
前記被処理水を前記脱塩室だけに通水すると共に、前記
濃縮室には海水を通水し、前記被処理水は、排煙脱硫排
水等のように硫酸カルシウム等の難溶性の塩類が含有さ
れていることを特徴とする。 請求項３の発明は、前記目
的を達成する為に、陽イオン交換膜と陰イオン交換膜を
電極間に交互に配列して交互に脱塩室と濃縮室を形成す
る電気透析装置に海水以外の被処理水を供給して前記被
処理水中の塩類を脱塩する電気透析装置による脱塩方法
において、前記被処理水を前記脱塩室だけに通水すると
共に、前記濃縮室には海水を通水し、前記被処理水を脱
塩室に通水する通水量と前記海水を前記濃縮室に通水す
る通水量を同程度にすることを特徴とする。 According to a first aspect of the present invention , a cation exchange membrane and an anion exchange membrane are alternately arranged between electrodes to alternately provide a desalting chamber and a concentrating chamber. In a desalination method using an electrodialysis apparatus for supplying water to be treated other than seawater to desalinate salts in the water to be treated by supplying the water to be treated to the electrodialysis apparatus, the water to be treated is passed only to the desalination chamber. together with the concentrated compartment is through water seawater, the seawater cooling
Used seawater for cooling water which is used as water and heated
It is water, this sea water and is characterized seawater der Rukoto that passed through the concentrating chamber. The invention of claim 2 achieves the above object.
Exchange the cation exchange membrane and the anion exchange membrane between the electrodes.
Electrodialysis arranged alternately to form a desalting chamber and a concentrating chamber
Supplying the water to be treated other than seawater to the device,
In a desalination method using an electrodialysis device for desalting salts,
While passing the treated water only to the desalination chamber,
Seawater is passed through the enrichment chamber, and the water to be treated is
Contains sparingly soluble salts such as calcium sulfate like water
It is characterized by having been done. The invention according to claim 3 is characterized in that the eye
Cation exchange membrane and anion exchange membrane
Arrange alternately between electrodes to form alternate desalination and concentration chambers
The water to be treated other than seawater is supplied to the electrodialysis
Desalting method using electrodialysis equipment for desalting salts in treated water
In the method, the water to be treated is passed only to the desalination chamber.
In both cases, seawater is passed through the enrichment chamber to remove the water to be treated.
Pass the amount of water passing through the salt room and the seawater to the concentration room
It is characterized in that the amount of water passing through is about the same.
【００１２】本発明によれば、海水以外の被処理水は脱
塩室側だけに通水し、濃縮室側には被処理水とは別の塩
類含有水である海水を通水するようにしたので、被処理
水の略全量を脱塩水として回収することができる。この
場合、海水ならば低コストで潤沢に入手可能なので、脱
塩室側の被処理水から濃縮室側の海水に透析したスケー
ル成分が濃縮室で析出しない程度に、濃縮室に通水する
海水を多量に供給すれば、スケールトラブルを確実に防
止することができ、しかもランニングコストが殆どかか
らない。また、濃縮室側で濃縮される濃縮水、即ち海水
の排水規制成分濃度が放流基準以下になるように濃縮室
に通水する海水の供給量を制御するなら、海水を排水処
理して放流する必要もない。According to the present invention, as other than seawater water to be treated is passed through only the desalting chamber side, the concentrating compartment side which passed through the sea water is another salt-containing water is water to be treated Therefore, almost all of the water to be treated can be recovered as desalinated water. In this case, since seawater can be obtained abundantly at low cost, the seawater passing through the concentration chamber is reduced to such an extent that scale components dialyzed from the water to be treated in the desalination chamber into the seawater in the concentration chamber do not precipitate in the concentration chamber. If a large amount of is supplied, the scale trouble can be reliably prevented, and the running cost is hardly required. Furthermore, concentrated water is concentrated in the concentrating compartment side, i.e. sea water
If drainage restricting component concentration to control the supply amount of the seawater passed through as the concentrating compartment becomes below effluent standard, there is no need to discharge to waste water treatment sea water.
【００１３】更に、塩類濃度の大きな海水を濃縮室に通
水することにより、限界電流密度を高めることができる
ので、電気透析装置の処理性能を向上させることができ
る。Furthermore, by passing water a large sea water salinity in concentrating compartment, it is possible to increase the critical current density, it is possible to improve the processing performance of the electrodialysis apparatus.
【００１４】[0014]
【発明の実施の形態】以下添付図面に従って本発明に係
る電気透析装置による脱塩方法の形態について詳説す
る。図１は、本発明の脱塩方法の実施の形態を適用する
電気透析装置の構成を説明する全体構成図である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a desalting method using an electrodialysis apparatus according to the present invention. FIG. 1 is an overall configuration diagram illustrating the configuration of an electrodialysis apparatus to which an embodiment of the desalting method of the present invention is applied.
【００１５】図１に示すように、電気透析装置１０は、
脱塩水系路１２と濃縮水系路１４とが分離独立した形で
形成され、脱塩水系路１２には脱塩水として処理される
被処理水が供給されると共に、濃縮水系路１４には濃縮
水として処理される海水が供給されるように構成され
る。脱塩水系路１２は、被処理水を濾過する濾過装置１
６と、濾過装置１６で濾過された被処理水が送水される
脱塩水槽１８及び送水ポンプ２０と、脱塩水槽１８と透
析槽２２内の脱塩室２４との間で被処理水を循環させる
循環ポンプ２６とで構成される。As shown in FIG. 1, the electrodialysis apparatus 10 comprises:
The desalinated water system 12 and the concentrated water system 14 are formed in a separate and independent manner, and the water to be treated as demineralized water is supplied to the desalinated water system 12 and the concentrated water system 14 is supplied to the concentrated water system 14. It is configured to supply seawater that is treated as. The desalination water passage 12 is provided with a filtration device 1 for filtering the water to be treated.
6, the desalinated water tank 18 and the water pump 20 to which the water to be treated filtered by the filtration device 16 is sent, and the water to be treated is circulated between the desalinated water tank 18 and the desalination chamber 24 in the dialysis tank 22. And a circulating pump 26 to be operated.
【００１６】濃縮水系路１４は、海水を濾過する濾過装
置２８と、濾過された海水が送水される濃縮水槽３０及
び送水ポンプ３２と、濃縮水槽３０と透析槽２２内の濃
縮室３４との間で海水を循環させる循環ポンプ３６とで
構成される。被処理水又は海水の濾過に用いる濾過装置
１６、２８としては、これらの水に含まれる懸濁性浮遊
物質（以下、ＳＳという）により電気透析装置１０の流
路の閉塞や後記するイオン交換膜への付着による処理性
能の低下を招かないように精密濾過が可能な濾過装置が
適切である。この濾過装置１６、２８により濾過された
被処理水又は海水のＳＳ濃度は０．５ｍｇ／ｌ以下であ
ることが好ましい。The concentrated water passage 14 includes a filtration device 28 for filtering seawater, a concentrated water tank 30 and a water pump 32 to which the filtered seawater is fed, and a concentrated water tank 30 and a concentration chamber 34 in the dialysis tank 22. And a circulation pump 36 for circulating seawater. As the filtration devices 16 and 28 used for filtering the water to be treated or seawater, the suspension of suspended matter (hereinafter, referred to as SS) contained in these waters may block the flow path of the electrodialysis device 10 or an ion exchange membrane described later. A filtration device capable of performing microfiltration so as not to cause a decrease in processing performance due to adhesion to the filter is appropriate. The SS concentration of the water to be treated or seawater filtered by the filtration devices 16 and 28 is preferably 0.5 mg / l or less.
【００１７】透析槽２２内には、図２に示すように、陽
イオン交換膜Ｃと陰イオン交換膜Ａとを交互に配列して
区画したエリアに、脱塩室２４と濃縮室３４とが交互に
形成され、脱塩室２４には被処理水が通水され、濃縮室
３４には海水が通水される。また、透析槽２２内におけ
るイオン交換膜群の両端には陽極３８と陰極４０が配置
され、陽極３８と陰極４０との間に直流電圧が印加され
る。これにより、脱塩室２４に通水された被処理水中の
塩類は、電離したＣａ2+，Ｎａ+ などの陽イオン交換膜
Ｃを透過して濃縮室３４側に透析（移動）し、Ｃｌ- ，
ＳＯ4 2-などの陰イオンが陰イオン交換膜Ａを透過して
濃縮室３４側に透析（移動）して脱塩される一方、濃縮
室３４では透析してきた塩類が海水に溶解して塩類濃度
が高くなる。As shown in FIG. 2, in the dialysis tank 22, a desalting chamber 24 and a concentrating chamber 34 are provided in an area in which cation exchange membranes C and anion exchange membranes A are alternately arranged. The water to be treated is passed alternately through the desalting chamber 24, and the seawater is passed through the concentration chamber 34. An anode 38 and a cathode 40 are arranged at both ends of the ion exchange membrane group in the dialysis tank 22, and a DC voltage is applied between the anode 38 and the cathode 40. Thereby, the salts in the water to be treated passed through the desalting chamber 24 permeate the cation exchange membrane C, such as Ca 2+ and Na +, and are dialyzed (moved) toward the concentration chamber 34 to remove Cl - ,
Anions such as SO 4 2- permeate the anion exchange membrane A and are dialyzed (moved) toward the concentration chamber 34 to be desalted, while in the concentration chamber 34, the dialyzed salts are dissolved in seawater to form salts. The concentration increases.
【００１８】次に、上記の如く構成された電気透析装置
１０を用いて本発明の脱塩方法を、被処理水としてスケ
ール成分を多く含有する排煙脱硫排水の脱塩を行う例で
説明する。脱塩水系路１２には、濾過装置１６で濾過し
た排煙脱硫排水だけを通水し、循環ポンプ２６により脱
塩水槽１８と脱塩室２４との間で循環させる。一方、濃
縮水系路１４には、濾過装置２８で濾過した海水を通水
し、循環ポンプ３６により濃縮水槽３０と濃縮室３４と
の間で循環させる。この状態で陽極３８と陰極４０との
間に直流電圧が印加されると、排煙脱硫排水中の塩類は
脱塩室２４から濃縮室３４側に透析（移動）する。これ
により、脱塩室２４に通水された排煙脱硫排水中の塩類
が脱塩されて脱塩水が生成される一方、濃縮室３４に通
水された海水中に塩類が濃縮されて濃縮水、即ち塩類濃
度が増加した海水が生成される。そして、脱塩された脱
塩水の一部は脱塩水槽１８から回収され、回収された分
だけ新たな排煙脱硫排水が脱塩水槽１８に供給される。Next, the desalination method of the present invention using the electrodialyzer 10 configured as described above will be described with an example in which desalination of flue gas desulfurization wastewater containing a large amount of scale components as water to be treated. . Only the flue gas desulfurization effluent filtered by the filtration device 16 is passed through the desalination water passage 12, and circulated between the desalination water tank 18 and the desalination chamber 24 by the circulation pump 26. On the other hand, the seawater filtered by the filtration device 28 is passed through the concentrated water system 14 and circulated between the concentrated water tank 30 and the concentration chamber 34 by the circulation pump 36. When a DC voltage is applied between the anode 38 and the cathode 40 in this state, the salts in the flue gas desulfurization effluent are dialyzed (moved) from the desalting chamber 24 to the concentration chamber 34 side. As a result, the salts in the flue gas desulfurization effluent passed through the desalination chamber 24 are desalted to produce desalinated water, while the salts are concentrated in the seawater passed through the concentration chamber 34 to form concentrated water. That is, seawater with increased salt concentration is produced. Then, a part of the desalted demineralized water is recovered from the desalination water tank 18, and fresh flue gas desulfurization wastewater is supplied to the desalination water tank 18 by the recovered amount.
【００１９】このように、本発明の電気透析装置による
脱塩方法では、被処理水である排煙脱硫排水を脱塩室２
４だけに供給し、従来のように、排煙脱硫排水を脱塩室
２４と濃縮室３４とに分配しないようにしたので、被処
理水の略全量を脱塩水として回収することができる。ま
た、この脱塩処理において、脱塩室２４側の排煙脱硫排
水から濃縮室３４側の海水に透析したスケール成分が濃
縮室３４で析出しないように、濃縮室３４に多量の海水
を供給すれば、スケールトラブルを確実に防止すること
ができる。具体的には、被処理水である排煙脱硫排水に
含有されていた塩類が全て濃縮室３４側の海水に移動し
たとして、脱塩水系路１２に供給する排煙脱硫排水の供
給量と同程度の海水を濃縮水系路１４に供給すれば良
い。これにより、スケールトラブルを回避することがで
きるので、安定運転を行うことができる。しかも、海水
ならば、多量の海水を低コストで容易に入手可能なの
で、ランニングコストが殆どかからない。一般的に、火
力発電所や工場は臨海地域に立地しているので、海水は
低コストで潤沢に入手可能である。As described above, in the desalination method using the electrodialysis apparatus of the present invention, the flue gas desulfurization effluent, which is the water to be treated, is supplied to the desalination chamber 2.
4, the flue gas desulfurization effluent is not distributed between the desalting chamber 24 and the concentrating chamber 34 as in the prior art, so that substantially all of the water to be treated can be recovered as desalinated water. In this desalination treatment, a large amount of seawater is supplied to the enrichment chamber 34 so that scale components dialyzed from the flue gas desulfurization wastewater on the desalination chamber 24 side into the seawater on the enrichment chamber 34 do not precipitate in the enrichment chamber 34. Thus, a scale trouble can be reliably prevented. Specifically, it is assumed that all of the salts contained in the flue gas desulfurization effluent, which is the water to be treated, have moved to the seawater on the enrichment chamber 34 side, and the supply amount of the flue gas desulfurization effluent to be supplied to the desalination water passage 12 is the same. It is only necessary to supply a certain amount of seawater to the concentrated water system 14. Thus, a scale trouble can be avoided, and stable operation can be performed. In addition, since seawater can be easily obtained at a low cost with a large amount of seawater, the running cost is hardly required. Generally, thermal power plants and factories are located in the coastal area, so seawater is available at low cost and abundantly.
【００２０】更に、濃縮室３４で濃縮される海水中の排
水規制成分濃度が放流基準を越えないように濃縮水系路
に供給する海水の供給量を制御すれば、海水をそのまま
海に放流することができる。従って、濃縮水である海水
を後工程で排水処理する必要がないので、ランニングコ
ストが大幅に低減する。また、塩類濃度の大きな海水を
濃縮室３４に通水することにより、限界電流密度を高め
ることができるので、電気透析装置１０の処理性能を向
上させることができる。この場合、濃縮室３４に通水す
る海水として、冷却水として使用され自らは昇温された
使用済の冷却水用海水を使用すると一層良い。この理由
は、従来、廃棄されていた使用済の冷却水用海水を有効
利用できる他に、昇温された海水を使用することによ
り、透析槽２２内の電気抵抗を低減でき、電流効率を向
上させることができるためで、ひいては処理性能の向上
を図ることができる。Further, if the supply amount of seawater supplied to the concentrated water system is controlled so that the concentration of the wastewater regulatory component in the seawater concentrated in the concentration chamber 34 does not exceed the discharge standard, the seawater can be discharged to the sea as it is. Can be. Therefore, it is not necessary to subject the concentrated seawater to wastewater treatment in a subsequent step, so that the running cost is greatly reduced. In addition, by passing seawater having a high salt concentration through the concentration chamber 34, the critical current density can be increased, so that the processing performance of the electrodialysis apparatus 10 can be improved. In this case, it is more preferable to use the used seawater for the cooling water which is used as the cooling water and which has been heated and used as the seawater passing through the concentration chamber 34. The reason for this is that, in addition to being able to effectively use the used seawater for cooling water that has been conventionally discarded, by using heated seawater, the electric resistance in the dialysis tank 22 can be reduced and the current efficiency can be improved. Therefore, the processing performance can be improved.
【００２１】尚、本実施の形態として、脱塩水系路１２
に供給する被処理水として排煙脱硫排水の例で説明した
が、これに限定されるものではなく、海水以外の塩類含
有水であれば全てに適用することができる。特に、本発
明の脱塩方法は、排煙脱硫排水のようにＣａＳＯ4 等の
難溶性の塩類を多く含みスケールトラブルが発生し易い
塩類含有水に最適である。In this embodiment, the desalinated water system 12
Although the example of the flue gas desulfurization effluent is described as the water to be supplied to the tank, the present invention is not limited to this, and may be applied to any salt-containing water other than seawater. In particular, the desalination method of the present invention is most suitable for salt-containing water, such as flue gas desulfurization effluent, which contains a large amount of hardly soluble salts such as CaSO 4 and is likely to cause scale trouble.
【００２２】[0022]
【００２３】[0023]
【実施例】次に、上記した図１の電気透析装置を用いて
本発明の電気透析装置による脱塩方法を実験した実施例
を説明する。被処理水としては火力発電所の排煙脱硫排
水を使用し、火力発電所近傍から採水した海水を用い、
脱塩室に排水を全量通水し、濃縮室に海水を全量通水す
る本発明の電気透析装置による脱塩方法により行った。EXAMPLE Next, an example in which a desalting method using the electrodialysis apparatus of the present invention was tested using the above-described electrodialysis apparatus of FIG. 1 will be described. As the water to be treated, use the flue gas desulfurization effluent of the thermal power plant, and use the seawater collected from near the thermal power plant,
It carried out by the desalination method by the electrodialysis apparatus of the present invention in which the entire amount of wastewater was passed through the desalting chamber and the entire amount of seawater was passed through the concentration chamber.
【００２４】実験装置の仕様並びに実験条件、及び排水
と海水の水質は（表１）及び（表２）に示す通りであ
る。The specifications of the experimental apparatus, the experimental conditions, and the effluent and seawater qualities are as shown in (Table 1) and (Table 2).
【００２５】[0025]
【表１】 [Table 1]
【００２６】[0026]
【表２】 表２より分かるように、排水中には、スケール成分であ
るカルシウムイオン（Ｃａ2+）が４５６ｍｇ／ｌ、硫酸
イオン（ＳＯ4 2-）が１０００ｍｇ／ｌ含まれており、
海水中には、Ｃａ2+が３５０ｍｇ／ｌ、ＳＯ4 2-が２６
００ｍｇ／ｌ含まれている。また、排水中の塩類濃度
（ＴＤＳ）は３５４０ｍｇ／ｌで、脱塩水としての処理
水の塩類濃度の管理目標値を４００ｍｇ／ｌ以下として
運転を行った。[Table 2] As can be seen from Table 2, the wastewater contains 456 mg / l of calcium ion (Ca 2+ ) and 1000 mg / l of sulfate ion (SO 4 2− ) as scale components.
In seawater, Ca 2+ contains 350 mg / l and SO 4 2-
00 mg / l. The operation was performed with a salt concentration (TDS) in the wastewater of 3540 mg / l and a control target value of the salt concentration of the treated water as the desalinated water of 400 mg / l or less.
【００２７】運転は、排水並びに海水の供給流量をいず
れも５リッター／時間と一定とし、荷電を一定電圧とし
て５００時間連続運転を行った。また、比較例として、
実施例と同じ排水を用いて、図５に示すように、排水を
脱塩室と濃縮室に分配する従来の電気透析装置による脱
塩方法により行い、その他は実施例と同様の実験条件で
行った。The operation was performed at a constant supply rate of 5 liters / hour for both the drainage and seawater supply rates, and a continuous operation was performed for 500 hours with a constant charge. As a comparative example,
Using the same wastewater as in the example, as shown in FIG. 5, the wastewater was distributed by a conventional desalting method using an electrodialysis apparatus in which the wastewater was distributed to a desalination chamber and a concentration chamber. Was.
【００２８】実験結果を評価するための測定データとし
ては、実施例及び比較例ともに、電流密度、電流効率及
び脱塩水の塩類濃度を、５００時間連続運転における経
時変化として把握できるようにした。図３は、本発明の
脱塩方法で行った実施例の実験結果であり、図４は、従
来の脱塩方法で行った比較例の実験結果である。As the measurement data for evaluating the experimental results, the current density, the current efficiency and the salt concentration of the demineralized water in both the examples and comparative examples can be grasped as changes over time in 500 hours of continuous operation. FIG. 3 shows an experimental result of an example performed by the desalting method of the present invention, and FIG. 4 shows an experimental result of a comparative example performed by the conventional desalting method.
【００２９】本実施例の場合には、図３から明らかなよ
うに、電流密度、電流効率及び脱塩水の塩類濃度ともに
５００時間経過後も運転開始時と同等であり、安定した
運転を行うことができた。また、得られた脱塩水の塩類
濃度も４００ｍｇ／ｌ以下となり工業用水（塩類濃度で
５００ｍｇ／ｌ以下であれば使用可）として十分満足で
きるものであった。In the case of this embodiment, as apparent from FIG. 3, the current density, the current efficiency, and the salt concentration of the deionized water are the same as those at the start of operation even after 500 hours, so that stable operation can be performed. Was completed. Further, the salt concentration of the obtained demineralized water was 400 mg / l or less, which was sufficiently satisfactory as industrial water (it can be used if the salt concentration is 500 mg / l or less).
【００３０】また、脱塩水の回収率は、生成される脱塩
水を貯留槽に一時貯留して単位時間当たりの流量を計測
して計算した結果、常時９７％以上を確保することがで
きた。これは、従来の脱塩方法が略５０％であることか
ら飛躍的な向上をみることができた。また、実験終了後
に、電気透析装置を解体して陰イオン交換膜のスケール
成分の有り無しを目視観察したが、スケールの析出は全
く認められなかった。The recovery rate of the demineralized water was calculated by measuring the flow rate per unit time by temporarily storing the generated demineralized water in a storage tank. As a result, a recovery rate of 97% or more was always maintained. This is a dramatic improvement since the conventional desalting method is about 50%. After the experiment was completed, the electrodialysis apparatus was disassembled, and the presence or absence of scale components in the anion exchange membrane was visually observed, but no scale deposition was observed.
【００３１】これに対し、比較例の場合には、図４から
明らかなように、運転開始から３０時間あたりから電流
密度、電流効率の低下が認められ、脱塩水の塩類濃度が
次第に増加すると共に、濃縮水に僅かな白濁が生じ始め
た。この白濁がスケールか否かの確認のために、実験終
了後に、電気透析装置を解体して陰イオン交換膜のスケ
ール成分の有り無しを目視観察したところ、白色の結晶
がイオン交換膜に付着していた。結晶を採取して分析し
た結果、二水石膏（ＣａＳＯ4 ・２Ｈ2 Ｏ）のスケール
であることが分かった。On the other hand, in the case of the comparative example, as is clear from FIG. 4, the current density and the current efficiency decreased from about 30 hours after the start of the operation, and the salt concentration of the demineralized water gradually increased. A slight cloudiness began to occur in the concentrated water. After the experiment, the electrodialysis device was disassembled and the presence or absence of scale components in the anion exchange membrane was visually observed to confirm whether or not the cloudiness was a scale.The white crystals adhered to the ion exchange membrane. I was As a result of collecting and analyzing the crystals, it was found that the scale was a scale of gypsum dihydrate (CaSO 4 .2H 2 O).
【００３２】[0032]
【発明の効果】以上説明したように、本発明の電気透析
装置による脱塩方法によれば、被処理水を脱塩室だけに
通水すると共に、濃縮室に海水を通水するようにしたの
で、被処理水の略全量を脱塩水として回収することがで
きる。従って、従来の電気透析装置による脱塩方法に比
べて脱塩水の回収率を飛躍的に向上させることができ
る。As described in the foregoing, according to the desalination process according to electrodialysis apparatus of the present invention, as well as passed through the treated water only desalting compartment, so that passed through the sea water to the concentrating compartment Therefore, almost all of the water to be treated can be recovered as desalinated water. Therefore, the recovery rate of the desalinated water can be dramatically improved as compared with the desalination method using the conventional electrodialysis apparatus.
【００３３】また、この脱塩処理において、脱塩室側の
被処理水から濃縮室側の海水に透析したスケール成分が
濃縮室で析出しない程度に濃縮室に多量の海水を供給す
れば、スケールトラブルを確実に防止することができ
る。従って、安定的な運転を行うことができると共に、
イオン交換膜にスケールが付着しないので、イオン交換
膜の寿命を延ばすことができる。Further, supplying a large amount of sea water into concentrate chamber to the desalting treatment Oite, to the extent that dialyzed scale components in the sea water in the concentrating compartment side from the treatment water desalination chamber side does not precipitate in the concentration chamber Then, the scale trouble can be surely prevented. Therefore, stable operation can be performed, and
Since scale does not adhere to the ion exchange membrane, the life of the ion exchange membrane can be extended.
【００３４】更に、濃縮された海水中の排水規制成分濃
度が放流基準を越えないように濃縮室に供給する海水の
供給量を制御するなら、海水をそのまま海に放流するこ
とができる。従って、従来のように濃縮水の排水処理を
行う必要がなくランニングコストが大幅に削減できる。Furthermore, the effluent control component concentration of the concentrated sea water is if controlling the <br/> supply amount of the sea water supplied to the concentrating chamber so as not to exceed the effluent standard, are discharged seawater as it is to the sea Can be. Therefore, it is not necessary to perform the wastewater treatment of the concentrated water unlike the related art, and the running cost can be greatly reduced.
【図１】図１は、本発明の脱塩方法を適用する電気透析
装置の構成を示す全体構成図FIG. 1 is an overall configuration diagram showing a configuration of an electrodialysis apparatus to which a desalting method of the present invention is applied.
【図２】図２は、電気透析装置の透析槽内を説明する説
明図FIG. 2 is an explanatory view illustrating the inside of a dialysis tank of the electrodialysis apparatus.
【図３】図３は、本発明の脱塩方法で行った実施例の結
果を示すグラフFIG. 3 is a graph showing the results of examples performed by the desalting method of the present invention.
【図４】図４は、従来の脱塩方法で行った比較例の結果
を示すグラフFIG. 4 is a graph showing the results of a comparative example performed by a conventional desalting method.
【図５】図５は、従来の脱塩方法を適用する電気透析装
置の構成を示す全体構成図FIG. 5 is an overall configuration diagram showing a configuration of an electrodialysis apparatus to which a conventional desalting method is applied.
１０…電気透析装置 １２…脱塩水系路 １４…濃縮水系路 １６、２８…濾過装置 １８…脱塩水槽 ２２…透析槽 ２４…脱塩室 ３０…濃縮水槽 ３４…濃縮室 ３８…陽極 ４０…陰極 Ａ…陰イオン交換膜 Ｃ…陽イオン交換膜 DESCRIPTION OF SYMBOLS 10 ... Electrodialysis apparatus 12 ... Demineralized water system path 14 ... Concentrated water system path 16, 28 ... Filtration apparatus 18 ... Demineralized water tank 22 ... Dialysis tank 24 ... Demineralization room 30 ... Concentrated water tank 34 ... Concentrated room 38 ... Anode 40 ... Cathode A: Anion exchange membrane C: Cation exchange membrane
───────────────────────────────────────────────────── フロントページの続き (72)発明者 内山 浩 東京都千代田区内神田１丁目１番14号 日立プラント建設株式会社内 (56)参考文献 特開 平９−85060（ＪＰ，Ａ) 特開 平７−8749（ＪＰ，Ａ) 特開 平６−285329（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C02F 1/46 B01D 61/44 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Uchiyama 1-1-14-1 Uchikanda, Chiyoda-ku, Tokyo Hitachi Plant Construction Co., Ltd. (56) References JP-A-9-85060 (JP, A) JP-A-7-8749 (JP, A) JP-A-6-285329 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C02F 1/46 B01D 61/44
Claims (3)
間に交互に配列して交互に脱塩室と濃縮室を形成する電
気透析装置に海水以外の被処理水を供給して前記被処理
水中の塩類を脱塩する電気透析装置による脱塩方法にお
いて、 前記被処理水を前記脱塩室だけに通水すると共に、前記
濃縮室には海水を通水し、 前記海水は、冷却水として使用され自らは昇温された使
用済の冷却水用海水であり、この海水とは濃縮室に通水
する海水であ ることを特徴とする電気透析装置による脱
塩方法。1. A method in which water to be treated other than seawater is supplied to an electrodialysis apparatus in which a cation exchange membrane and an anion exchange membrane are alternately arranged between electrodes to alternately form a desalting chamber and a concentration chamber. in desalination method salts in the treated water by electrodialysis apparatus for desalination, the while passed through only the desalting treatment water, the sea water was passed water to the concentrating compartment, wherein the seawater cooling Used as water and heated
Used seawater for cooling water, which is passed through the enrichment room
Desalting process according to electrodialysis device comprising seawater der Rukoto to.
間に交互に配列して交互に脱塩室と濃縮室を形成する電
気透析装置に海水以外の被処理水を供給して前記被処理
水中の塩類を脱塩する電気透析装置による脱塩方法にお
いて、 前記被処理水を前記脱塩室だけに通水すると共に、前記
濃縮室には海水を通水し、 前記被処理水は、排煙脱硫排水等のように硫酸カルシウ
ム等の難溶性の塩類が含有されていることを特徴とする
電気透析装置による脱塩方法。2. A cation exchange membrane and an anion exchange membrane each comprising an electrode.
Between the electrodes to alternately form a desalination chamber and a concentration chamber.
Supplying the water to be treated other than seawater to the
The desalination method using an electrodialyzer that desalinates salts in water
And passing the treated water only to the desalination chamber,
Rohm & seawater to concentration compartment, the water to be treated, you characterized in that the salts of poorly soluble calcium sulfate and the like are contained as such waste water of flue gas desulfurization
Desalting process according to the electric dialysis machine.
間に交互に配列して交互に脱塩室と濃縮室を形成する電
気透析装置に海水以外の被処理水を供給して前記被処理
水中の塩類を脱塩する電気透析装置による脱塩方法にお
いて、 前記被処理水を前記脱塩室だけに通水すると共に、前記
濃縮室には海水を通水し、 前記被処理水を脱塩室に通水する通水量と前記海水を前
記濃縮室に通水する通水量を同程度にすることを特徴と
する電気透析装置による脱塩方法。3. A cation exchange membrane and an anion exchange membrane each comprising an electrode.
Between the electrodes to alternately form a desalination chamber and a concentration chamber.
Supplying the water to be treated other than seawater to the
The desalination method using an electrodialyzer that desalinates salts in water
And passing the treated water only to the desalination chamber,
Seawater is passed through the concentrating chamber, and the amount of water for passing the treated water to the desalting chamber is substantially equal to the amount of water for passing the seawater to the concentrating chamber. desalting process according to the electric dialysis machine you.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23893496A JP3271744B2 (en) | 1996-09-10 | 1996-09-10 | Desalting method using electrodialysis equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23893496A JP3271744B2 (en) | 1996-09-10 | 1996-09-10 | Desalting method using electrodialysis equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1085755A JPH1085755A (en) | 1998-04-07 |
| JP3271744B2 true JP3271744B2 (en) | 2002-04-08 |
Family
ID=17037458
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23893496A Expired - Fee Related JP3271744B2 (en) | 1996-09-10 | 1996-09-10 | Desalting method using electrodialysis equipment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3271744B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2007049549A1 (en) * | 2005-10-27 | 2009-04-30 | 日清紡績株式会社 | Method for producing fine particles of salt, hydroxide or oxide, and fine particles of salt, hydroxide or oxide obtained by the production method |
| WO2008044544A1 (en) * | 2006-10-04 | 2008-04-17 | Nisshinbo Industries, Inc. | Fine particle of hydroxide and/or oxide and process for producing the same |
| US8864911B2 (en) * | 2009-03-26 | 2014-10-21 | General Electric Company | Method for removing ionic species from desalination unit |
| US9339765B2 (en) | 2011-09-16 | 2016-05-17 | General Electric Company | Electrodialysis method and apparatus for passivating scaling species |
-
1996
- 1996-09-10 JP JP23893496A patent/JP3271744B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH1085755A (en) | 1998-04-07 |
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