JP2000024638A - Evaporative concentrating method of sulfuric acid- containing waste water and evaporative concentrating device - Google Patents
Evaporative concentrating method of sulfuric acid- containing waste water and evaporative concentrating deviceInfo
- Publication number
- JP2000024638A JP2000024638A JP10192018A JP19201898A JP2000024638A JP 2000024638 A JP2000024638 A JP 2000024638A JP 10192018 A JP10192018 A JP 10192018A JP 19201898 A JP19201898 A JP 19201898A JP 2000024638 A JP2000024638 A JP 2000024638A
- Authority
- JP
- Japan
- Prior art keywords
- wastewater
- concentrating
- seed crystal
- evaporating
- sulfuric acid
- 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.)
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- Treating Waste Gases (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Heat Treatment Of Water, Waste Water Or Sewage (AREA)
- Removal Of Specific Substances (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、スケール抑制のた
めに種晶を添加して排煙脱硫排水等の硫酸含有排水を蒸
発濃縮する硫酸含有排水の処理方法に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating sulfuric acid-containing wastewater by evaporating and concentrating sulfuric acid-containing wastewater such as flue gas desulfurization wastewater by adding seed crystals to suppress scale.
【０００２】[0002]
【従来の技術】従来、排煙脱硫プロセスから排出された
硫黄分を含む硫酸含有排水の処理方法としては、硫酸含
有排水に凝集剤を添加してする凝集沈殿濾過法が一般的
である。しかしながら、凝集沈殿濾過法は、凝集沈殿装
置を設置するための広い面積が必要であり、さらに多量
の廃スラッジが発生するため運転管理が煩雑となる欠点
を有している。特に火力火力発電所における排煙脱硫排
水を処理するためには、２段の凝集沈殿によるフッ素除
去や、ＣＯＤ吸着設備を必要とするなど複雑な工程や設
備を必要とし、その運転経費、添加薬品費さらには保守
費用の面で不経済であった。2. Description of the Related Art Conventionally, as a method of treating sulfuric acid-containing wastewater containing sulfur components discharged from a flue gas desulfurization process, a coagulation sedimentation filtration method in which a coagulant is added to sulfuric acid-containing wastewater is generally used. However, the coagulation-sedimentation filtration method has a disadvantage that a large area is required for installing a coagulation-sedimentation apparatus, and furthermore, a large amount of waste sludge is generated, so that the operation management becomes complicated. In particular, in order to treat flue gas desulfurization effluent in thermal power plants, complicated processes and equipment are required, such as the need for fluorine removal by coagulation and sedimentation in two stages, and COD adsorption equipment. It was uneconomical in terms of costs and maintenance costs.
【０００３】一方、凝集沈殿濾過法に代わる処理法とし
て、火力発電所から排出される排煙脱硫排水を蒸発濃縮
する蒸発濃縮法が提案されている。蒸発濃縮法は、凝集
沈殿濾過法と比して、システムが簡素で設置面積も少な
いという利点を有している。しかしながら、火力発電所
から排出される排水、特に排煙脱硫排水中には、カルシ
ウムイオン、マグネシウムイオン、硫酸イオン等の多量
のスケール成分が含まれているため、蒸発濃縮法で排水
を処理しようとすると、蒸発濃縮工程においてスケール
が生成し、蒸発濃縮器の伝熱管にスケールが付着して伝
熱効率が低下したり、配管が閉塞する等の障害により連
続的に処理することは困難である。On the other hand, an evaporative concentration method for evaporating and condensing flue gas desulfurization effluent discharged from a thermal power plant has been proposed as a treatment method replacing the coagulation sedimentation filtration method. The evaporative concentration method has an advantage that the system is simple and the installation area is small as compared with the coagulation sedimentation filtration method. However, wastewater discharged from thermal power plants, especially flue gas desulfurization wastewater, contains a large amount of scale components such as calcium ions, magnesium ions, and sulfate ions. Then, scale is generated in the evaporative concentration step, and the scale adheres to the heat transfer tube of the evaporative concentrator, so that it is difficult to continuously process due to obstacles such as a decrease in heat transfer efficiency and a blockage of the pipe.
【０００４】火力発電所等から排出される排煙脱硫排水
等を蒸発濃縮する際に、蒸発濃縮装置内のスケーリング
を抑制する目的で、種晶を濃縮液に添加することは有効
である。種晶を添加することにより、濃縮液中の種晶に
スケール成分が析出するため、スケール成分が配管、タ
ンク類、濃縮装置に析出することが抑制される。[0004] When evaporating and condensing flue gas desulfurization effluent discharged from a thermal power plant or the like, it is effective to add a seed crystal to the concentrated liquid for the purpose of suppressing scaling in the evaporative concentration apparatus. By adding the seed crystal, the scale component precipitates on the seed crystal in the concentrated liquid, and therefore, the scale component is prevented from depositing on piping, tanks, and a concentration device.
【０００５】また、種晶の濃度を保持する場合は例え
ば、サイクロンセパレーター等の粒体分離器により蒸発
濃縮装置内の循環液中の種晶を系内で回収することは一
般に行われている。この場合、種晶濃度の調整方法とし
て、外部からの種晶の添加、装置外への抜き出し、装置
内回収を組み合わせているが、回収した種晶に関しては
蒸発濃縮装置内へそのまま返送しているのが現状であ
る。In order to maintain the concentration of seed crystals, for example, it is common practice to recover the seed crystals in the circulating liquid in the evaporating and concentrating apparatus by a granular separator such as a cyclone separator in the system. In this case, as a method of adjusting the seed crystal concentration, the addition of the seed crystal from outside, extraction from the apparatus, and recovery in the apparatus are combined, but the recovered seed crystal is returned to the evaporating and concentrating apparatus as it is. is the current situation.
【０００６】図３に従来方法として、サイクロンセパレ
ータを用いた２段蒸発濃縮装置によるの硫酸含有排水の
蒸発濃縮方法のフロー図を示す。FIG. 3 shows a flow chart of a conventional method for evaporating and concentrating sulfuric acid-containing wastewater by a two-stage evaporative concentrator using a cyclone separator.
【０００７】排煙脱硫排水は排水供給ラインａａよりｐ
Ｈ調整タンク１に流入させ、酸あるいはアルカリを貯蔵
しているｐＨ調整薬品タンク１１からｐＨ調整薬品注入
ポンプ１３を介してｐＨ調整薬品を注入し、蒸発濃縮液
のｐＨが弱酸性から中性になるようにｐＨを調整する。
同時に石膏スラリータンク１２に貯蔵してある種晶とし
ての石膏のスラリーを石膏スラリー注入ポンプ１４によ
って注入する。[0007] The flue gas desulfurization wastewater is supplied from the wastewater supply line aa to p.
The pH-adjusting chemical is injected from the pH-adjusting chemical tank 11 storing the acid or alkali through the pH-adjusting chemical injection pump 13 so that the pH of the evaporative concentrate changes from weakly acidic to neutral. Adjust the pH so that
At the same time, gypsum slurry as a seed crystal stored in the gypsum slurry tank 12 is injected by the gypsum slurry injection pump 14.
【０００８】ｐＨ調整した排水を排水供給ポンプ１５を
介して１段目蒸発濃縮器２に供給する。１段目蒸発濃縮
器２および２段目蒸発濃縮器３はコンデンサ４を介して
真空ポンプ２０により約−６００ｍｍＨｇの減圧状態と
し、加熱用蒸気ラインｂｂより供給される蒸気を加熱源
とし、約６０℃で排水を蒸発させる。１段目蒸発器２お
よび２段目蒸発器３で蒸発した蒸気はコンデンサ４で凝
縮し、凝縮水ポンプ２１により凝縮水タンク５へ排出す
る。２段目蒸発濃縮器３から２段目濃縮液排出ポンプ１
９を介して排出された濃縮液はサイクロンセパレータ２
８に送られる。サイクロンセパレータ２８で分離された
小粒径部分は上澄水タンク２９に貯蔵され上澄水ポンプ
３２によって２段目蒸発濃縮器３へ戻す。サイクロンセ
パレータ２８で分離された大粒径部分は濃縮液貯蔵タン
ク６へ貯蔵し調整濃縮液ポンプ３１へ戻し、調整濃縮液
が設定値以上となったら調整濃縮液排出ポンプ２４を介
して濃縮液タンク１０へ排出する。The wastewater whose pH has been adjusted is supplied to the first-stage evaporative concentrator 2 through a wastewater supply pump 15. The first-stage evaporator / concentrator 2 and the second-stage evaporator / concentrator 3 are brought into a reduced pressure state of about -600 mmHg by the vacuum pump 20 via the condenser 4, and the steam supplied from the heating steam line bb is used as a heating source. Evaporate the wastewater at ° C. The vapor evaporated by the first-stage evaporator 2 and the second-stage evaporator 3 is condensed by the condenser 4 and discharged to the condensed water tank 5 by the condensed water pump 21. Second-stage concentrated liquid discharge pump 1 from second-stage evaporator 3
The concentrated liquid discharged through 9 is the cyclone separator 2
8 The small particle size portion separated by the cyclone separator 28 is stored in the supernatant water tank 29 and returned to the second-stage evaporative concentrator 3 by the supernatant water pump 32. The large particle diameter portion separated by the cyclone separator 28 is stored in the concentrated liquid storage tank 6 and returned to the adjusted concentrated liquid pump 31. When the adjusted concentrated liquid has exceeded the set value, the concentrated liquid tank is passed through the adjusted concentrated liquid discharging pump 24. Discharge to 10.
【０００９】[0009]
【発明が解決しようとする課題】図３に示したような蒸
発濃縮装置内に設置されたサイクロンセパレータなどに
よる粒体分離器は、濃縮装置内に種晶を維持させるもの
であり、濃縮装置前段の例えばｐＨ調整用タンク類への
スケーリングは抑制できない。濃縮装置内と比較すると
濃縮前に析出するスケール成分は少ないが、スケール成
分濃度が高く過飽和に近い排水では濃縮前のスケーリン
グも重大な問題となる。従来の粒体分離器では種晶のみ
ではなく、ＮａＣｌ，Ｎａ2ＳＯ4等の溶存塩類を含む混
合液として回収される。従って、種晶供給を目的として
蒸発濃縮装置へ返送した場合に、種晶とともに溶存塩類
も返送されるため、１段目蒸発濃縮器内の循環濃縮液の
溶存塩濃度が上昇して沸点上昇を招き、濃縮効率の低下
を起こす。A particle separator such as a cyclone separator installed in an evaporating and concentrating apparatus as shown in FIG. 3 is for maintaining seed crystals in the concentrating apparatus, and is provided in a stage upstream of the concentrating apparatus. For example, scaling to tanks for pH adjustment cannot be suppressed. Compared with the inside of the concentrator, the scale component precipitated before the concentration is small, but the scaling before the concentration becomes a serious problem in the wastewater where the concentration of the scale component is high and close to supersaturation. In the conventional particle separator, not only the seed crystals but also a mixed liquid containing dissolved salts such as NaCl and Na 2 SO 4 is recovered. Therefore, when returned to the evaporative concentration apparatus for the purpose of supplying seed crystals, dissolved salts are also returned together with the seed crystals, so that the dissolved salt concentration of the circulating concentrated liquid in the first-stage evaporative concentrator rises and the boiling point rises. Causes the concentration efficiency to decrease.
【００１０】本発明が解決しようとする課題は、種晶を
添加して硫酸含有排水の蒸発濃縮を行う方法において、
濃縮効率を低下させることなく、蒸発濃縮器内部のみな
らず、前段の排水供給ラインのスケーリングを有効に抑
制する硫酸含有排水の処理方法を提供することにある。An object of the present invention is to provide a method for evaporating and concentrating sulfuric acid-containing wastewater by adding a seed crystal.
An object of the present invention is to provide a method for treating sulfuric acid-containing wastewater, which effectively suppresses scaling of not only the inside of the evaporative concentrator but also the preceding wastewater supply line without reducing the concentration efficiency.
【００１１】[0011]
【課題を解決するための手段】上記課題を解決するため
の請求項１に記載された本発明は、硫酸含有排水の種晶
を利用してスケーリングを抑制する硫酸含有排水の蒸発
濃縮方法において、蒸発濃縮器の循環濃縮液または排出
濃縮液の一部を分離して種晶を固液分離し、固液分離し
た種晶を水で洗浄して種晶中に含まれる溶存塩類を取り
除いた後、該種晶を蒸発濃縮器の前段へ返送することを
特徴とする硫酸含有排水の蒸発濃縮方法に関するもので
ある。According to a first aspect of the present invention, there is provided a method for evaporating and concentrating a sulfuric acid-containing wastewater, the method comprising using a seed crystal of the sulfuric acid-containing wastewater to suppress scaling. After separating a part of the circulating concentrate or the discharged concentrate of the evaporating concentrator, solid-liquid separation of the seed crystal is performed, and the solid-liquid separated seed crystal is washed with water to remove dissolved salts contained in the seed crystal. The present invention also relates to a method for evaporating and concentrating sulfuric acid-containing wastewater, wherein the seed crystal is returned to a stage preceding the evaporator.
【００１２】上記課題を解決するための請求項２に記載
された本発明は、硫酸含有排水の種晶を利用してスケー
リングを抑制する硫酸含有排水の処理方法において、蒸
発濃縮器の循環濃縮液または排出濃縮液中の一部を分離
し、種晶を小粒径部分と大粒径部分に分級し、小粒径部
分を固液分離した後、分離した種晶を水で洗浄して種晶
中に含まれる溶存塩類を取り除いた後、該種晶を蒸発濃
縮器の前段へ返送することを特徴とする硫酸含有排水の
蒸発濃縮方法に関するものである。According to a second aspect of the present invention, there is provided a method for treating a sulfuric acid-containing wastewater, the method comprising using a seed crystal of the sulfuric acid-containing wastewater to suppress scaling. Alternatively, a part of the discharged concentrate is separated, the seed crystal is classified into a small particle part and a large particle part, and the small particle part is subjected to solid-liquid separation.The separated seed crystal is washed with water and seeded. The present invention relates to a method for evaporating and concentrating sulfuric acid-containing wastewater, which comprises removing dissolved salts contained in crystals and returning the seed crystals to a stage preceding an evaporator.
【００１３】上記課題を解決するための請求５に記載さ
れた本発明は硫酸含有排水中の水分を蒸発させて前記排
水を濃縮する蒸発濃縮装置において、前記排水に種晶を
添加する種晶添加手段と、前記排水のｐＨを調整するｐ
Ｈ調整手段と、前処理された排水を蒸発濃縮する蒸発濃
縮手段と、濃縮された排水を蒸発濃縮手段へ循環する濃
縮液循環手段と、循環濃縮液または排出濃縮液の一部を
固液分離する固液分離手段と、固液分離した種晶を水で
洗浄する洗浄手段と、洗浄された種晶を蒸発濃縮手段の
前段へ返送する種晶返送手段を有することを特徴とする
硫酸含有排水の蒸発濃縮装置に関するものである。According to a fifth aspect of the present invention, there is provided an evaporative concentration apparatus for evaporating water in a sulfuric acid-containing wastewater and concentrating the wastewater, wherein a seed crystal is added to the wastewater. Means for adjusting the pH of the wastewater
H adjusting means, evaporating and concentrating means for evaporating and concentrating the pretreated wastewater, condensate circulating means for circulating the concentrated wastewater to the evaporating and concentrating means, and solid-liquid separation of a part of the circulating condensate or discharged condensate A sulfuric acid-containing effluent, comprising: a solid-liquid separation unit that performs separation; a washing unit that cleans the solid-liquid separated seed crystals with water; and a seed crystal return unit that returns the washed seed crystals to a stage preceding the evaporation and concentration unit. The present invention relates to an evaporating and concentrating device.
【００１４】上記課題を解決するための請求項６に記載
された本発明は、硫酸含有排水中の水分を蒸発させて前
記排水を濃縮する蒸発濃縮装置において、前記排水に種
晶を添加する種晶添加手段と、前記排水のｐＨを調整す
るｐＨ調整手段と、前処理された排水を蒸発濃縮する蒸
発濃縮手段と、濃縮された排水を蒸発濃縮手段へ戻す濃
縮液循環手段と、循環濃縮液または排出濃縮液の一部を
取出し含まれるＳＳ成分を小粒径部分と大粒径部分に分
級する分級手段と、分級された小粒径部分を固液分離す
る固液分離手段と、固液分離した種晶を水で洗浄する洗
浄手段と、洗浄された種晶を蒸発濃縮手段の前段へ返送
する種晶返送手段を有することを特徴とする硫酸含有排
水の蒸発濃縮装置に関するものである。According to a sixth aspect of the present invention, there is provided an evaporative concentration apparatus for evaporating water in sulfuric acid-containing wastewater and concentrating the wastewater, wherein a seed crystal is added to the wastewater. Crystal addition means, pH adjusting means for adjusting the pH of the wastewater, evaporative concentration means for evaporating and concentrating the pretreated wastewater, concentrated liquid circulation means for returning the concentrated wastewater to the evaporative concentration means, and circulating concentrated liquid A classifying means for taking out a part of the discharged concentrated liquid and classifying the contained SS component into a small particle size part and a large particle size part; a solid-liquid separating means for solid-liquid separating the classified small particle size part; The present invention relates to an apparatus for evaporating and concentrating sulfuric acid-containing wastewater, comprising: a washing means for washing separated seed crystals with water; and a seed crystal returning means for returning the washed seed crystals to a stage preceding the evaporating and concentrating means.
【００１５】[0015]
【発明の実施の形態】本発明方法は、硫酸含有排水に含
まれる種晶を利用してスケーリングを抑制するを行う硫
酸含有排水の蒸発濃縮処理方法において、蒸発濃縮器の
循環濃縮液の一部を固液分離し、循環濃縮液にＳＳ成分
として含まれている種晶を分離し、分離された種晶に少
量含まれる溶存塩類を凝縮水で洗浄して溶存塩類を取り
除き、溶存塩類が除かれた種晶を、蒸発濃縮器の前段に
返送することを特徴とするものである。溶存塩類が取り
除かれているので、蒸発濃縮器内の循環濃縮液の沸点上
昇を招くことがなく、濃縮効率が低下することがない。
また、回収した種晶を濃縮器前段に返送するため、蒸発
濃縮器内部だけでなく、排水供給ラインのスケーリング
を抑制することができる。さらに回収した種晶を再利用
できるため、種晶の消費量を低減することができる。BEST MODE FOR CARRYING OUT THE INVENTION The method of the present invention relates to a method for evaporating and concentrating sulfuric acid-containing wastewater, which suppresses scaling by using seed crystals contained in the sulfuric acid-containing wastewater. Is separated into solid and liquid, the seed crystals contained as SS components in the circulating concentrated solution are separated, and the dissolved salts contained in a small amount in the separated seed crystals are washed with condensed water to remove the dissolved salts, and the dissolved salts are removed. The seed crystal is returned to a stage preceding the evaporator. Since the dissolved salts have been removed, the boiling point of the circulating concentrate in the evaporator does not rise, and the concentration efficiency does not decrease.
In addition, since the recovered seed crystals are returned to the former stage of the concentrator, scaling of not only the inside of the evaporator but also the drainage supply line can be suppressed. Furthermore, since the recovered seed crystal can be reused, the consumption of the seed crystal can be reduced.
【００１６】本発明における処理対象となる硫酸含有排
水とは硫酸成分を含む排水であり、例えば石炭火力発電
所等で使用される湿式石灰石−石膏法スート混合式排煙
脱硫装置から排出される硫酸イオンを含む排煙脱硫排水
を挙げることができる。The sulfuric acid-containing wastewater to be treated in the present invention is a wastewater containing a sulfuric acid component, for example, sulfuric acid discharged from a wet limestone-gypsum method soot flue gas desulfurization apparatus used in a coal-fired power plant or the like. Examples include flue gas desulfurization wastewater containing ions.
【００１７】本発明における種晶とは、例えば排煙脱硫
排水に含まれる硫酸カルシウムが付着し得うる母核とな
るものであれば特に限定されないが、スケール抑制効果
や、例えば石炭火力発電所内での入手のしやすさ等の理
由により、石膏が好ましい。処理しようとする硫酸含有
排水中に含まれる種晶濃度が少ない場合は、外部から種
晶を添加し、また硫酸含有排水中に含まれる種晶が十分
ある場合は、外部から種晶を加えずに回収再利用すれば
よい。The seed crystal in the present invention is not particularly limited as long as it serves as a mother nucleus to which calcium sulfate contained in flue gas desulfurization effluent can adhere, for example. Gypsum is preferred for reasons such as easy availability. If the concentration of seed crystals contained in the sulfuric acid-containing wastewater to be treated is low, add seed crystals from the outside.If there is enough seed crystals contained in the sulfuric acid-containing wastewater, do not add seed crystals from the outside. It can be collected and reused.
【００１８】本発明における蒸発濃縮手段としての蒸発
濃縮器は、どのような型式のものでもよく、水平伝熱管
方式でも縦型薄膜方式でもよい。蒸発濃縮するための加
熱方式も、外部加熱方式でも自己蒸気圧縮型でもよい。
また、蒸発濃縮器は１段のものでも、２段以上のもので
もよい。The evaporative concentrator as the evaporative concentrating means in the present invention may be of any type, and may be a horizontal heat transfer tube type or a vertical thin film type. The heating method for evaporating and concentrating may be an external heating method or a self-vapor compression type.
The evaporator may be a single-stage evaporator or two or more stages.
【００１９】本発明における固液分離手段は、蒸発濃縮
器の循環濃縮液中のＳＳ成分としての石膏と析出した溶
存塩類を分離できる手段であれば特に限定されないが、
例えば、遠心脱水機、フィルタープレス脱水機、膜型分
離器、沈降機等を挙げることができる。The solid-liquid separation means in the present invention is not particularly limited as long as it can separate gypsum as an SS component and precipitated dissolved salts in the circulating concentrate of the evaporator.
For example, a centrifugal dehydrator, a filter press dehydrator, a membrane separator, a sedimenter and the like can be mentioned.
【００２０】なお、蒸発濃縮器として２段の蒸発濃縮器
を使用する場合、固液分離するのは２段目の蒸発濃縮器
の循環濃縮液または排出濃縮液であり、３段以上の蒸発
濃縮器を使用する場合には、最終段蒸発濃縮器の循環濃
縮液または排出濃縮液である。When a two-stage evaporative concentrator is used as the evaporative concentrator, it is the circulating concentrate or discharged condensate of the second-stage evaporative concentrator that separates into solid and liquid. When a vessel is used, it is a recirculating concentrate or a discharged concentrate of the final-stage evaporative concentrator.
【００２１】請求項２に記載の本発明において、蒸発濃
縮器の循環濃縮液のＳＳ成分を分級して小粒径部分を取
り出し、固液分離するのは、小粒径の種晶を回収するこ
とにより、単位重量当たりの表面積（比表面積）が大き
な種晶を再利用できるため、同重量でも種晶効果が大き
く、効果的にスケーリングを抑制できるためである。分
級手段は液体中の固体粒子を分級できる手段であれば特
に限定されないが、例えばサイクロンセパレータを挙げ
ることができる。本発明における小粒径部分とは、平均
粒径が５〜５０μｍ程度のものをいう。According to the second aspect of the present invention, the SS component of the circulating concentrate of the evaporating concentrator is classified, a small particle size portion is taken out, and solid-liquid separation is performed. This is because a seed crystal having a large surface area per unit weight (specific surface area) can be reused, so that the seed crystal effect is large even with the same weight, and scaling can be effectively suppressed. The classification means is not particularly limited as long as it can classify the solid particles in the liquid, and examples thereof include a cyclone separator. The small particle size portion in the present invention means a portion having an average particle size of about 5 to 50 μm.
【００２２】サイクロンセパレータを用いて小粒径種晶
を分級する場合は、小粒径種晶を透過させることなく、
確実に捕捉することができ、凝縮水を用いて逆洗するこ
とで容易に小粒径種晶のスラリーを得ることができる等
の理由により、濃縮液から種晶と溶存塩類を分離する手
段としてＭＦ膜を用いた膜型分離器が好適である。本発
明における固液分離手段としてのＭＦ膜としては、例え
ばメムテック社製精密濾過膜「型式Ｍ１０Ｃ」（公称孔
径０．２μｍ、膜面積１５ｍ3）を用いることができ
る。ＭＦ膜への通液方式は、デッドエンドフロー方式で
もクロスフロー方式でもよい。When classifying the small-sized seed crystal using a cyclone separator, the small-sized seed crystal is not permeated,
As a means to separate the seed crystals and dissolved salts from the concentrated solution, for example, because they can be reliably captured and a slurry of small grain seed crystals can be easily obtained by backwashing with condensed water, etc. A membrane separator using an MF membrane is preferred. As the MF membrane as the solid-liquid separation means in the present invention, for example, a microfiltration membrane “model M10C” (nominal pore diameter 0.2 μm, membrane area 15 m 3 ) manufactured by Memtech can be used. The method of passing the liquid through the MF membrane may be a dead end flow method or a cross flow method.
【００２３】固液分離により分離した種晶を、水で洗浄
し種晶中に含まれる溶存塩類を溶出させて溶存塩類を除
去する場合、洗浄水は水道水や工業用水を用いてもよい
が、蒸発濃縮器から得られる凝縮水を用いることが好ま
しい。凝縮水は、通常電気伝導率５０μＳ／ｃｍ以下、
ＳＳ成分を含まず、ＦＩ値４以下と清澄であり、塩分洗
浄に適している。特に分離手段として、孔径の小さいＭ
Ｆ膜型固液分離器を用いる場合には、洗浄水として凝縮
水を用いれば、ＳＳの除去等の前処理を施すことなく使
用することができる。なお溶存塩類の除去は完全に行う
必要はなく、例えば回収した種晶を１０％スラリーにし
たとき塩濃度０．２％程度になればよく、前段へ返送し
た時の原排水塩濃度増加率が１０％以内になる程度に除
去できればよい。When the seed crystals separated by solid-liquid separation are washed with water to dissolve dissolved salts contained in the seed crystals to remove dissolved salts, tap water or industrial water may be used as washing water. It is preferable to use condensed water obtained from an evaporator. The condensed water usually has an electric conductivity of 50 μS / cm or less,
It contains no SS component and is clear with an FI value of 4 or less, and is suitable for washing with salt. In particular, as a separating means, M having a small pore diameter is used.
When using the F membrane type solid-liquid separator, if condensed water is used as the washing water, it can be used without performing pretreatment such as removal of SS. It is not necessary to completely remove the dissolved salts. For example, when the recovered seed crystals are made into a 10% slurry, the salt concentration may be about 0.2%. What is necessary is just to be able to remove to the extent of being within 10%.
【００２４】固液分離した、種晶から溶存塩類を洗浄除
去するため、回収種晶を再利用しても、溶存塩類が濃縮
液に返送されることがないので、循環濃縮液の沸点上昇
を招くことがなく、濃縮効率が低下することがない。Since the dissolved salts are washed and removed from the seed crystals separated by solid-liquid separation, even if the recovered seed crystals are reused, the dissolved salts are not returned to the concentrated solution. There is no inconvenience and the concentration efficiency does not decrease.
【００２５】溶存塩類を除去した種晶は、凝縮水とのス
ラリーまたは脱水ケーキとして蒸発濃縮器の前段へ返送
するが、脱水ケーキを種晶として添加する場合には粉砕
器等で粉末状にして排水と混合しやくすることが望まし
い。蒸発濃縮器の前段とは、蒸発濃縮器へ導入される前
の工程であれば、特に限定されないが、例えば、含硫廃
液のｐＨを調整するためのｐＨ調整タンク等を挙げるこ
とができる。蒸発濃縮器の前段へ回収した種晶を返送す
ることにより、蒸発濃縮器のみならず、その前段にある
ｐＨ調整タンク等へのスケーリングの抑制を図ることが
できる。The seed crystals from which the dissolved salts have been removed are returned to the previous stage of the evaporator as a slurry with condensed water or as a dewatered cake. It is desirable to make it easier to mix with wastewater. The pre-stage of the evaporative concentrator is not particularly limited as long as it is a step before being introduced into the evaporative concentrator, and examples thereof include a pH adjusting tank for adjusting the pH of the sulfur-containing waste liquid. By returning the recovered seed crystals to the preceding stage of the evaporative concentrator, it is possible to suppress the scaling of not only the evaporative concentrator but also the pH adjustment tank and the like in the preceding stage.
【００２６】以下図面により本発明方法の実施形態を説
明する。An embodiment of the method of the present invention will be described below with reference to the drawings.
【００２７】図１は、請求項５に記載された本発明の蒸
発濃縮装置の一実施形態を示すフロー図である。なお図
１で示したフロー図は、蒸発濃縮器として２段の蒸発濃
縮器を用いた実施形態である。FIG. 1 is a flow chart showing an embodiment of the evaporative concentration apparatus according to the present invention. The flow chart shown in FIG. 1 is an embodiment using a two-stage evaporative concentrator as the evaporative concentrator.
【００２８】図１において、図３の従来例と同一の要素
には同一の符号を付した。図１のフロー図において前段
の処理および蒸発濃縮のプロセスは図３に示したものと
同じであるので、説明を省略する。In FIG. 1, the same elements as those in the conventional example of FIG. 3 are denoted by the same reference numerals. In the flow chart of FIG. 1, the processing of the preceding stage and the process of evaporative concentration are the same as those shown in FIG.
【００２９】１段目の蒸発濃縮器２で濃縮された濃縮液
は１段目濃縮液循環ポンプ１６を介して常時循環され、
一定濃度まで濃縮された循環濃縮液は、濃縮液排出ポン
プ１７により２段目蒸発濃縮器３へ送られる。２段目蒸
発濃縮器３で濃縮された濃縮液の一部は２段目濃縮液循
環ポンプ１８を介して常時循環され、一定濃度に達する
と濃縮液排出ポンプ１９により濃縮液調整タンク６に送
られる。濃縮調整タンク６へ送られた濃縮液の一部は調
整濃縮液排出ポンプ２４を介して濃縮液タンク１０へ排
出し、残りの液は調整濃縮液移送ポンプ２５を介して一
部を２段目蒸発濃縮器３へ返送し、残りをＭＦ膜モジュ
ール７へ供給する。ＭＦ膜モジュール７へ供給された濃
縮液中のＳＳ成分である種晶と溶存塩類はＭＦ膜モジュ
ール７で濾過される。ＭＦ膜モジュール７で濾過された
濾液は濾液タンク８に送られる。この濾液は濾液ポンプ
２６によって濃縮液タンク１０へ移送する。ＭＦ膜モジ
ュール７は一定時間毎に逆洗によりＭＦ膜の目詰まりを
防止するが、逆洗を行う直前に、ＭＦ膜上に濾別された
種晶に含まれる溶存塩類を除去するために、凝縮水を凝
縮水タンク５より凝縮水供給ポンプ２３よりＭＦ膜の濾
過面に供給して、膜面の種晶に含まれる塩類を除去させ
る。溶存塩類を除去した後、凝縮水タンク５に貯蔵して
いた凝縮水を用いて、凝縮水供給ポンプ２３を介してＭ
Ｆ膜モジュール７を逆洗する。種晶が含まれた逆洗水
は、回収種晶タンク９に貯められた後、回収種晶移送ポ
ンプ２７に石膏スラリータンク１２へ戻す。返送される
回収種晶は凝縮水で洗浄しているため、溶存塩類が取り
除かれており、この回収種晶を再利用しても、循環濃縮
液の沸点が上昇することがなく、蒸発濃縮を効率よく行
うことができる。The concentrate concentrated in the first-stage evaporative concentrator 2 is constantly circulated through the first-stage concentrate circulating pump 16.
The circulating concentrate concentrated to a certain concentration is sent to the second-stage evaporative concentrator 3 by the concentrate discharge pump 17. Part of the concentrated liquid concentrated in the second-stage evaporative concentrator 3 is constantly circulated through the second-stage concentrated liquid circulating pump 18, and is sent to the concentrated liquid adjusting tank 6 by the concentrated liquid discharge pump 19 when reaching a certain concentration. Can be Part of the concentrated liquid sent to the concentration adjusting tank 6 is discharged to the concentrated liquid tank 10 via the adjusted concentrated liquid discharge pump 24, and the remaining liquid is partially transferred to the second stage through the adjusted concentrated liquid transfer pump 25. It is returned to the evaporative concentrator 3 and the remainder is supplied to the MF membrane module 7. Seed crystals and dissolved salts, which are SS components, in the concentrate supplied to the MF membrane module 7 are filtered by the MF membrane module 7. The filtrate filtered by the MF membrane module 7 is sent to a filtrate tank 8. This filtrate is transferred to the concentrate tank 10 by the filtrate pump 26. The MF membrane module 7 prevents clogging of the MF membrane by backwashing at regular intervals, but immediately before performing backwashing, in order to remove dissolved salts contained in seed crystals filtered on the MF membrane, Condensed water is supplied from the condensed water tank 5 to the filtration surface of the MF membrane from the condensed water supply pump 23 to remove salts contained in seed crystals on the membrane surface. After removing the dissolved salts, the condensed water stored in the condensed water tank 5 is used to condense M
The F membrane module 7 is backwashed. The backwash water containing the seed crystal is stored in the recovery seed crystal tank 9 and then returned to the gypsum slurry tank 12 by the recovery seed crystal transfer pump 27. Since the recovered seed crystal returned is washed with condensed water, the dissolved salts have been removed, and even if this recovered seed crystal is reused, the boiling point of the circulating concentrated solution does not increase, and the evaporative concentration is reduced. It can be performed efficiently.
【００３０】図２は、請求項６に記載された本発明の蒸
発濃縮装置の一実施形態を示すフロー図である。なお図
２で示したフロー図は、蒸発濃縮器として２段の蒸発濃
縮器を用いた実施形態である。FIG. 2 is a flow chart showing one embodiment of the evaporative concentration apparatus according to the present invention. The flow chart shown in FIG. 2 is an embodiment using a two-stage evaporative concentrator as the evaporative concentrator.
【００３１】図１において、図３の従来例と同一の要素
には同一の符号を付した。図１のフロー図において前段
の処理および蒸発濃縮のプロセスは図３に示したものと
同じであるので、説明を省略する。In FIG. 1, the same elements as those of the conventional example of FIG. 3 are denoted by the same reference numerals. In the flow chart of FIG. 1, the processing of the preceding stage and the process of evaporative concentration are the same as those shown in FIG.
【００３２】２段目蒸発濃縮器３から２段目蒸発濃縮液
排出ポンプ１９を介して排出された濃縮液はサイクロン
セパレータ２８に送る。サイクロンセパレータ２８で分
離された小粒径部分は上澄水タンク２９に貯蔵され上澄
水ポンプ３０によって、ＭＦ膜モジュール７へ送る。Ｍ
Ｆ膜モジュール７から排出される濾液は、濾液タンク８
に送り、この濾液は濾液ポンプ２６によって濃縮液タン
ク１０へ送る。上澄水に含まれていたＳＳ成分として種
晶の小粒径部分はＭＦ膜面上に蓄積し、濾過能力が低下
してくるため、一定時間毎に逆洗を行ってＭＦ膜の目詰
まりを防止しなくてはならないが、逆洗をする直前にＭ
Ｆ膜面上の種晶から溶存塩類を取り除くため、凝縮水を
凝縮水タンク５より凝縮水供給ポンプ２３よりＭＦ膜の
濾過面に供給して、溶存塩類を除去する。溶存塩類を除
去した後、凝縮水タンク５に貯蔵していた凝縮水を用い
て、凝縮水供給ポンプ２３を介してＭＦ膜モジュール７
を逆洗する。種晶が含まれた逆洗水は、回収種晶タンク
９に貯められた後、回収種晶移送ポンプ２７に石膏スラ
リータンク１２へ戻す。返送される回収種晶は凝縮水で
洗浄しているため、溶存塩類が取り除かれており、この
回収種晶を再利用しても、循環濃縮液の沸点が上昇する
ことがなく、蒸発濃縮を効率よく行うことができる。The concentrate discharged from the second-stage evaporative concentrator 3 via the second-stage evaporative concentrate discharge pump 19 is sent to the cyclone separator 28. The small particle size portion separated by the cyclone separator 28 is stored in the supernatant water tank 29 and sent to the MF membrane module 7 by the supernatant water pump 30. M
The filtrate discharged from the F membrane module 7 is supplied to a filtrate tank 8
The filtrate is sent to the concentrate tank 10 by the filtrate pump 26. As the SS component contained in the supernatant water, the small particle size portion of the seed crystal accumulates on the MF membrane surface, and the filtration ability is reduced. Therefore, the MF membrane is clogged by backwashing at regular intervals. It must be prevented, but M
In order to remove dissolved salts from the seed crystals on the F membrane surface, condensed water is supplied from the condensed water tank 5 to the filtration surface of the MF membrane from the condensed water supply pump 23 to remove the dissolved salts. After removing the dissolved salts, the condensed water stored in the condensed water tank 5 is used to feed the MF membrane module 7 through the condensed water supply pump 23.
Backwash. The backwash water containing the seed crystal is stored in the recovered seed crystal tank 9 and then returned to the gypsum slurry tank 12 by the recovered seed crystal transfer pump 27. Since the recovered seed crystal returned is washed with condensed water, the dissolved salts have been removed, and even if this recovered seed crystal is reused, the boiling point of the circulating concentrated liquid does not increase, and the evaporative concentration is reduced. It can be performed efficiently.
【００３３】なお、サイクロンセパレータ２８で分離さ
れた大粒径部分は、濃縮液調整タンク６へ貯蔵し調整濃
縮ポンプ３１により２段目蒸発濃縮器３へ戻し、調整濃
縮液濃度が設定値以上になったら調整濃縮液排出ポンプ
２４を介して濃縮液タンク１０へ排出すればよい。The large particle diameter portion separated by the cyclone separator 28 is stored in the concentrated liquid adjusting tank 6 and returned to the second-stage evaporative concentrator 3 by the adjusted concentrated pump 31 so that the adjusted concentrated liquid concentration becomes equal to or higher than the set value. Then, it may be discharged to the concentrate tank 10 via the adjusted concentrate discharge pump 24.
【００３４】[0034]
【実施例】実施例１ 石炭火力発電所の石灰石−石膏スート混合式排煙脱硫装
置から排出される排煙脱硫排水を対象に本発明方法によ
り蒸発濃縮処理を行った。従来の種晶回収方法と本発明
方法の石膏スラリー使用量および蒸発濃縮装置内の循環
濃縮液中の種晶粒径を比較した。処理対象とする硫酸含
有排水は、スート混合型脱硫排水を模擬するためにスー
ト混合型脱硫排水に薬品を添加した模擬排水を用いた。
この模擬排水の水質を表１に示す。EXAMPLE 1 Evaporation and concentration treatment was performed by the method of the present invention on flue gas desulfurization wastewater discharged from a limestone-gypsum soot mixed flue gas desulfurization unit of a coal-fired power plant. The amount of gypsum slurry used in the conventional seed crystal recovery method and the method of the present invention and the seed crystal particle size in the circulating concentrate in the evaporative concentration apparatus were compared. As the sulfuric acid-containing wastewater to be treated, simulated wastewater obtained by adding a chemical to soot-mixed desulfurization wastewater to simulate soot-mixed desulfurization wastewater was used.
Table 1 shows the water quality of this simulated wastewater.
【００３５】[0035]
【表１】 [Table 1]
【００３６】スケーリング抑制のための種晶としては石
炭火力発電所で回収される高品位石膏の粉末を用い、こ
の高品位石膏を工業用水に混合した１０ｗ／ｖ％スラリ
ーを装置供給用種晶として用いた。排水への添加は排水
中のＳＳ濃度が８０００ｍｇ／ｌとなるように調整し、
図３に示した従来方法と、図２に示した本発明方法で運
転時間１００ｈにおける装置外から供給する石膏スラリ
ー使用量と２段目蒸発濃縮装置内の循環濃縮液中ＳＳ
（種晶）粒径の比較を行った。その結果を表２に示す。As a seed crystal for suppressing the scaling, a high-grade gypsum powder recovered at a coal-fired power plant is used, and a 10 w / v% slurry obtained by mixing this high-grade gypsum with industrial water is used as a seed crystal for supplying to an apparatus. Using. The addition to the wastewater was adjusted so that the SS concentration in the wastewater was 8000 mg / l,
In the conventional method shown in FIG. 3 and the method of the present invention shown in FIG. 2, the amount of gypsum slurry supplied from outside the apparatus during an operation time of 100 h and SS in the circulating concentrate in the second-stage evaporative concentration apparatus
(Seed crystal) The particle size was compared. Table 2 shows the results.
【００３７】なお、装置の処理量は１００ｌ／ｈ、濃縮
倍率は１５倍で高品位石膏の粒径は４０μｍである。本
発明方法で使用したＭＦ膜モジュールは、メムテック社
製精密濾過膜（型式Ｍ１０Ｃ）を用いた。サイクロンセ
パレータで分離した種晶の小粒径部分は、粒径範囲５〜
５０μｍであった。The throughput of the apparatus was 100 l / h, the concentration ratio was 15 times, and the particle size of the high-grade gypsum was 40 μm. As the MF membrane module used in the method of the present invention, a microfiltration membrane (Model M10C) manufactured by Memtech was used. The small particle size portion of the seed crystal separated by the cyclone separator has a particle size range of 5 to 5.
It was 50 μm.
【００３８】[0038]
【表２】 [Table 2]
【００３９】表２の結果から明らかなように、本発明法
による処理方法では、石膏スラリーの使用量が約２０％
減少し、循環濃縮液中の種晶粒径も大径化していなこと
が確認された。従来法による処理方法では、２段目蒸発
濃縮器のみに種晶を返送して濃度の維持を行うため、２
段目蒸発濃縮器の種晶濃度のみが高濃度になる。本発明
方法では、回収種晶を１段目濃縮装置前段に戻し、１段
目と２段目の蒸発濃縮装置に返送した種晶を供給してい
るため、１段目、２段目濃縮倍率に応じた種晶濃度を維
持できる。As is clear from the results in Table 2, in the treatment method according to the present invention, the amount of the gypsum slurry used was about 20%.
It was confirmed that the diameter of the seed crystal in the circulating concentrate did not increase. In the treatment method according to the conventional method, the seed crystals are returned only to the second-stage evaporator to maintain the concentration.
Only the seed crystal concentration of the stage evaporator becomes high. In the method of the present invention, the recovered seed crystal is returned to the previous stage of the first-stage concentrator, and the returned seed crystal is supplied to the first-stage and second-stage evaporative concentrators. Can be maintained in accordance with the concentration of the seed crystal.
【００４０】また、スケーリング抑制効果を比較するた
めに、排水中のＳＳ濃度を２０００ｍｇ／ｌに調整して
２００時間運転後の付着スケール厚みを測定した。表３
にその結果を示す。To compare the effect of suppressing scaling, the SS concentration in the wastewater was adjusted to 2000 mg / l, and the thickness of the adhered scale after 200 hours of operation was measured. Table 3
Shows the results.
【００４１】[0041]
【表３】 [Table 3]
【００４２】表３に示した結果から明らかなように、同
濃度の種晶濃度であっても、濃縮器前段へ戻す本発明方
法はスケーリング抑制効果が高いことが分かる。As is evident from the results shown in Table 3, it can be seen that the method of the present invention, in which the seed crystal concentration is the same, returns to the previous stage of the concentrator, has a high scaling suppressing effect.
【００４３】実施例２ 溶存塩類返送の有無による蒸発量変化を測定するため、
溶存塩類を含む種晶を返送して利用した場合と、溶存塩
類を本発明方法によって除いた後に利用した場合の１段
目蒸発濃縮器蒸発量と沸点上昇の変化を調べた結果を図
４および図５に示す。Example 2 In order to measure the change in the amount of evaporation depending on whether or not the dissolved salts were returned,
FIG. 4 and FIG. 4 show the results of examining the changes in the evaporation amount and the rise in the boiling point of the first-stage evaporative concentrator in the case where the seed crystals containing the dissolved salts are returned and used, and in the case where the dissolved salts are used after being removed by the method of the present invention. As shown in FIG.
【００４４】１段目蒸発濃縮器はヒートポンプによって
熱を回収しており、蒸発した蒸気を圧縮して昇温させ、
加熱用蒸気として再利用する方式である。沸点上昇を起
こすと発生蒸気温度に比べて循環濃縮液温度が高くなる
ため、蒸発させるのに必要な昇温幅も大きくなり、ヒー
トポンプも大型のものが要求される。ヒートポンプの能
力が一定で循環濃縮液の沸点上昇を起こした場合には蒸
発量は低下し、蒸発濃縮効率の低下を起こす。The first-stage evaporative concentrator recovers heat by a heat pump, and compresses the evaporated vapor to raise the temperature.
This is a system that is reused as heating steam. When the boiling point rises, the temperature of the circulating concentrated liquid becomes higher than the temperature of the generated steam, so that the temperature increase required for evaporation becomes large, and a large heat pump is required. When the heat pump capacity is constant and the boiling point of the circulating concentrate rises, the amount of evaporation decreases and the efficiency of evaporation and concentration decreases.
【００４５】図４に示した結果から明らかなように、溶
存塩類を含んだ種晶を前段へ返送し再利用した場合には
運転時間の増加と共に沸点が上昇し、蒸発量が減少して
いる。As is apparent from the results shown in FIG. 4, when the seed crystals containing the dissolved salts are returned to the previous stage and reused, the boiling point increases with an increase in the operation time, and the amount of evaporation decreases. .
【００４６】図５に示した結果から明らかなように、本
発明法によって溶存塩類を除いて前段へ返送し、再利用
した場合には、運転時間の増加によっても沸点上昇、蒸
発量に変化がなく、蒸発濃縮効率の低下がない運転が可
能であった。As is evident from the results shown in FIG. 5, when the present invention is used to remove dissolved salts, return to the former stage, and reuse, the boiling point rises and the amount of evaporation changes even with an increase in operation time. Thus, operation without a decrease in the evaporative concentration efficiency was possible.
【００４７】[0047]
【発明の効果】請求項１および請求項５に記載の本発明
により、回収した種晶から溶存塩類を取り除くので、回
収種晶を返送して再利用しても、循環濃縮液の溶存塩濃
度が上昇することがないため、循環濃縮液の沸点上昇を
招くことがなく、蒸発濃縮効率が低下することがない。
また、回収した種晶を蒸発濃縮器前段へ返送するため、
蒸発濃縮器のみならず、その前段のｐＨ調整タンク等の
スケーリングを抑制することができる。According to the present invention as set forth in claims 1 and 5, since dissolved salts are removed from the recovered seed crystals, even if the recovered seed crystals are returned and reused, the dissolved salt concentration of the circulating concentrate is reduced. Does not rise, so that the boiling point of the circulating concentrate does not rise, and the efficiency of evaporation and concentration does not decrease.
Also, in order to return the recovered seed crystals to the previous stage of the evaporator,
It is possible to suppress scaling of not only the evaporating concentrator but also the preceding pH adjusting tank and the like.
【００４８】請求項２および請求項５に記載の本発明に
より、小粒径部分の種晶を回収するので、単位重量当た
りの表面積（比表面積）が大きな種晶を再利用できるた
め、同重量でも種晶効果が大きく、効果的にスケーリン
グを抑制できる。According to the second and fifth aspects of the present invention, a seed crystal having a small particle size is recovered, and a seed crystal having a large surface area per unit weight (specific surface area) can be reused. However, the seed crystal effect is large, and scaling can be suppressed effectively.
【００４９】請求項３および請求項６に記載の本発明に
より、固液分離手段としてＭＦ膜を用いるので、微細な
種晶を透過させることなく確実に捕捉でき、凝縮水を用
いて逆洗することにより回収した種晶を含む混合液を容
易に得ることができるため、前段への返送が効率よくで
きる。According to the third and sixth aspects of the present invention, since the MF membrane is used as the solid-liquid separation means, fine seed crystals can be reliably trapped without permeation, and backwashing is performed using condensed water. As a result, a mixed liquid containing the recovered seed crystals can be easily obtained, so that the liquid can be efficiently returned to the former stage.
【００５０】請求項４に記載の本発明により、固液分離
した種晶から溶存塩類を取り除く媒体として凝縮水を用
いるので、ＳＳの除去等の前処理を施すことなく使用す
ることができ、処理効率を向上することができる。According to the fourth aspect of the present invention, since condensed water is used as a medium for removing dissolved salts from solid-liquid separated seed crystals, it can be used without pretreatment such as removal of SS. Efficiency can be improved.
【図１】請求項１に記載の本発明方法の一実施形態を示
すフロー図。FIG. 1 is a flowchart showing one embodiment of the method of the present invention described in claim 1.
【図２】請求項２に記載の本発明方法の一実施形態を示
すフロー図。FIG. 2 is a flowchart showing an embodiment of the method of the present invention described in claim 2.
【図３】従来方法のフロー図。FIG. 3 is a flowchart of a conventional method.
【図４】１段目蒸発濃縮器の蒸発量と沸点上昇を示すグ
ラフ（固液分離なし）。FIG. 4 is a graph showing the amount of evaporation and the rise in boiling point of the first-stage evaporative concentrator (without solid-liquid separation).
【図５】１段目蒸発濃縮器の蒸発量と沸点上昇を示すグ
ラフ（固液分離あり）。FIG. 5 is a graph showing the amount of evaporation and the rise in boiling point of the first-stage evaporative concentrator (with solid-liquid separation).
ａａ 排水供給ライン ｂｂ 加熱用蒸気ライン ｃｃ 冷却水入り口ライン ｄｄ 冷却水出口ライン １ ｐＨ調整タンク ２ １段目蒸発濃縮器 ３ ２段目蒸発濃縮器 ４ コンデンサ ５ 凝縮水タンク ６ 濃縮液調整タンク ７ ＭＦ膜モジュール ８ 濃縮濾液タンク ９ 種晶回収タンク １０ 濃縮液タンク １１ ｐＨ調整薬品タンク １２ 石膏スラリータンク １３ ｐＨ調整薬品注入ポンプ １４ 石膏スラリー注入ポンプ １５ 排水供給ポンプ １６ １段目濃縮液循環ポンプ １７ １段目濃縮液排出ポンプ １８ ２段目濃縮液循環ポンプ １９ ２段目濃縮液排出ポンプ ２０ 真空ポンプ ２１ 凝縮水ポンプ ２２ 蒸気ドレンポンプ ２３ 凝縮水供給ポンプ ２４ 調整濃縮液排出ポンプ ２５ 調整濃縮液移送ポンプ ２６ 濃縮濾液ポンプ ２７ 種晶移送ポンプ ２８ サイクロンセパレータ ２９ 上澄水タンク ３０ 上澄水ポンプ ３１ 調整濃縮液ポンプ aa Wastewater supply line bb Heating steam line cc Cooling water inlet line dd Cooling water outlet line 1 pH adjustment tank 2 First stage evaporator / concentrator 3 Second stage evaporator / concentrator 4 Condenser 5 Condensed water tank 6 Concentrated liquid adjustment tank 7 MF Membrane module 8 Concentrated filtrate tank 9 Seed crystal recovery tank 10 Concentrated liquid tank 11 pH-adjusted chemical tank 12 Gypsum slurry tank 13 pH-adjusted chemical injection pump 14 Gypsum slurry injection pump 15 Drainage supply pump 16 First-stage concentrated liquid circulation pump 17 1-stage Concentrated liquid discharge pump 18 Second-stage concentrated liquid circulation pump 19 Second-stage concentrated liquid discharge pump 20 Vacuum pump 21 Condensed water pump 22 Steam drain pump 23 Condensed water supply pump 24 Adjusted concentrated liquid discharge pump 25 Adjusted concentrated liquid transfer pump 26 Concentrated filtrate pump 27 Seed crystal transfer pump 28 cycle Emissions separator 29 above supernatant water tank 30 above supernatant water pump 31 adjusted concentrate pump
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｂ０１Ｄ 9/02 ６１０ Ｂ０１Ｄ 9/02 ６１０Ｚ ６１５ ６１５Ａ ６１７ ６１７ 53/50 Ｃ０２Ｆ 1/44 Ｅ 53/77 1/58 Ｑ Ｃ０２Ｆ 1/44 5/00 ６１０Ｚ 1/58 ６２０Ｂ 5/00 ６１０ Ｂ０１Ｄ 53/34 １２５Ｒ ６２０ (72)発明者 細田 浩一 東京都江東区新砂１丁目２番８号 オルガ ノ株式会社内 (72)発明者 高橋 英紀 東京都江東区新砂１丁目２番８号 オルガ ノ株式会社内 (72)発明者 塩見 裕 大阪府大阪市西淀川区竹島４丁目７番32号 株式会社ササクラ内 (72)発明者 田原 一見 大阪府大阪市西淀川区竹島４丁目７番32号 株式会社ササクラ内 Ｆターム(参考） 4D002 AA02 BA02 DA05 DA16 EA07 4D006 GA07 KA01 KB30 PB08 PB27 PC80 4D034 AA27 BA01 BA05 CA12 4D038 AA08 AB13 BA04 BB02 BB13 BB17 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) B01D 9/02 610 B01D 9/02 610Z 615 615A 617 617 53/50 C02F 1/44 E 53/77 1 / 58 Q C02F 1/44 5/00 610Z 1/58 620B 5/00 610 B01D 53/34 125R 620 (72) Inventor Koichi Hosoda 1-2-2 Shinsuna, Koto-ku, Tokyo Organo Corporation (72) Inventor Hideki Takahashi Organo Co., Ltd. 1-2-8 Shinsuna, Koto-ku, Tokyo (72) Inventor Hiroshi Shiomi 4-7-32 Takeshima, Nishiyodogawa-ku, Osaka-shi, Osaka Prefecture Sasakura Co., Ltd. (72) Inventor Tahara At first glance 4-7-32 Takeshima, Nishiyodogawa-ku, Osaka-shi, Osaka F-term in Sasakura Inc. (reference) 4D002 AA02 BA02 DA05 DA16 DA16 EA07 4D006 GA07 KA01 KB30 PB08 PB27 PC80 4D034 AA27 BA01 BA05 CA12 4D038 AA08 AB13 BA04 BB02 BB13 BB17
Claims (7)
リングを抑制する硫酸含有排水の蒸発濃縮方法におい
て、蒸発濃縮器の循環濃縮液または排出濃縮液の一部を
分離して種晶を固液分離し、固液分離した種晶を水で洗
浄して種晶中に含まれる溶存塩類を取り除いた後、該種
晶を蒸発濃縮器の前段へ返送することを特徴とする硫酸
含有排水の蒸発濃縮方法。1. A method for evaporating and concentrating sulfuric acid-containing wastewater by using a seed crystal in a sulfuric acid-containing wastewater to suppress scaling, wherein a part of a circulating concentrate or a discharged concentrate of an evaporator is separated to form a seed crystal. A sulfuric acid-containing wastewater characterized in that after solid-liquid separation, the seed crystals subjected to solid-liquid separation are washed with water to remove dissolved salts contained in the seed crystals, and then the seed crystals are returned to the preceding stage of the evaporator. Evaporation method.
ングを抑制する硫酸含有排水の処理方法において、蒸発
濃縮器の循環濃縮液または排出濃縮液中の一部を分離
し、種晶を小粒径部分と大粒径部分に分級し、小粒径部
分を固液分離した後、分離した種晶を水で洗浄して種晶
中に含まれる溶存塩類を取り除いた後、該種晶を蒸発濃
縮器の前段へ返送することを特徴とする硫酸含有排水の
蒸発濃縮方法。2. A method for treating a sulfuric acid-containing wastewater, which uses a seed crystal of the sulfuric acid-containing wastewater to suppress scaling by using a seed crystal of the sulfuric acid-containing wastewater. After classifying into a particle size portion and a large particle size portion, and solid-liquid separation of the small particle size portion, the separated seed crystal is washed with water to remove dissolved salts contained in the seed crystal, and then the seed crystal is removed. A method for evaporating and concentrating sulfuric acid-containing wastewater, comprising returning the mixture to a stage preceding the evaporator.
徴とする請求項１または請求項２に記載の硫酸含有排水
の処理方法。3. The method for treating sulfuric acid-containing wastewater according to claim 1, wherein the solid-liquid separation is performed using an MF membrane.
水が凝縮水であることを特徴とする請求項１ないし請求
項３のいずれか１項に記載の硫酸含有排水の処理方法。4. The method for treating a sulfuric acid-containing wastewater according to claim 1, wherein the water for washing the seed crystals and the dissolved salts separated from the solid and liquid is condensed water.
排水を濃縮する蒸発濃縮装置において、 前記排水に種晶を添加する種晶添加手段と、前記排水の
ｐＨを調整するｐＨ調整手段と、前処理された排水を蒸
発濃縮する蒸発濃縮手段と、濃縮された排水を蒸発濃縮
手段へ循環する濃縮液循環手段と、循環濃縮液または排
出濃縮液の一部を固液分離する固液分離手段と、固液分
離した種晶を水で洗浄する洗浄手段と、洗浄された種晶
を蒸発濃縮手段の前段へ返送する種晶返送手段を有する
ことを特徴とする硫酸含有排水の蒸発濃縮装置。5. An evaporating and concentrating apparatus for evaporating water in sulfuric acid-containing wastewater and concentrating the wastewater, comprising: seed crystal adding means for adding seed crystals to the wastewater; and pH adjusting means for adjusting the pH of the wastewater. Evaporating and concentrating means for evaporating and concentrating the pretreated wastewater, a concentrate circulating means for circulating the concentrated wastewater to the evaporating and concentrating means, and a solid-liquid separation for solid-liquid separating a part of the circulating concentrated liquid or the discharged concentrated liquid Means, a washing means for washing solid-liquid separated seed crystals with water, and a seed crystal returning means for returning the washed seed crystals to a stage preceding the evaporating and concentrating means. .
排水を濃縮する蒸発濃縮装置において、 前記排水に種晶を添加する種晶添加手段と、前記排水の
ｐＨを調整するｐＨ調整手段と、前処理された排水を蒸
発濃縮する蒸発濃縮手段と、濃縮された排水を蒸発濃縮
手段へ戻す濃縮液循環手段と、循環濃縮液または排出濃
縮液の一部を取出し含まれるＳＳ成分を小粒径部分と大
粒径部分に分級する分級手段と、分級された小粒径部分
を固液分離する固液分離手段と、固液分離した種晶を水
で洗浄する洗浄手段と、洗浄された種晶を蒸発濃縮手段
の前段へ返送する種晶返送手段を有することを特徴とす
る硫酸含有排水の蒸発濃縮装置。6. An evaporating and concentrating apparatus for evaporating water in sulfuric acid-containing wastewater and concentrating the wastewater, comprising: seed crystal adding means for adding seed crystals to the wastewater; and pH adjusting means for adjusting the pH of the wastewater. Evaporating and concentrating means for evaporating and concentrating the pretreated wastewater, concentrating liquid circulation means for returning the concentrated wastewater to the evaporating and concentrating means, and removing a part of the circulating condensate or discharged condensate to reduce the contained SS component into small particles Classifying means for classifying into a diameter portion and a large particle size portion, solid-liquid separating means for solid-liquid separating the classified small particle size portion, washing means for washing the solid-liquid separated seed crystal with water, An apparatus for evaporating and concentrating sulfuric acid-containing wastewater, comprising a seed crystal returning means for returning seed crystals to a stage preceding the evaporating and concentrating means.
ことを特徴とする請求項５または請求項６に記載の蒸発
濃縮装置。7. The evaporative concentrator according to claim 5, wherein the solid-liquid separation means is an MF membrane solid-liquid separator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19201898A JP3366258B2 (en) | 1998-07-07 | 1998-07-07 | Method and apparatus for evaporating and concentrating sulfuric acid-containing wastewater |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19201898A JP3366258B2 (en) | 1998-07-07 | 1998-07-07 | Method and apparatus for evaporating and concentrating sulfuric acid-containing wastewater |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000024638A true JP2000024638A (en) | 2000-01-25 |
| JP3366258B2 JP3366258B2 (en) | 2003-01-14 |
Family
ID=16284237
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19201898A Expired - Fee Related JP3366258B2 (en) | 1998-07-07 | 1998-07-07 | Method and apparatus for evaporating and concentrating sulfuric acid-containing wastewater |
Country Status (1)
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|---|---|
| JP (1) | JP3366258B2 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002292201A (en) * | 2001-03-30 | 2002-10-08 | Japan Organo Co Ltd | Crystallization reaction apparatus provided with means for vaporizing/concentrating treated water |
| JP2006305541A (en) * | 2005-03-30 | 2006-11-09 | Sasakura Engineering Co Ltd | Method and apparatus for treating waste water containing calcium and sulfuric acid |
| CN103101989A (en) * | 2013-02-05 | 2013-05-15 | 双良节能系统股份有限公司 | Self-cleaning high-salt wastewater evaporative crystallization device |
| JP2015062897A (en) * | 2002-11-13 | 2015-04-09 | デカ・プロダクツ・リミテッド・パートナーシップ | Distillation method with vapor pressurization |
| JP2018130717A (en) * | 2017-02-16 | 2018-08-23 | 一般財団法人電力中央研究所 | Processing method and system for treatment of desulfurization waste water |
| CN111003870A (en) * | 2019-12-27 | 2020-04-14 | 攀钢集团西昌钢钒有限公司 | Desulfurization wastewater treatment method and treatment device |
| CN114835321A (en) * | 2022-04-14 | 2022-08-02 | 光大环保技术研究院（南京）有限公司 | Evaporation system |
-
1998
- 1998-07-07 JP JP19201898A patent/JP3366258B2/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002292201A (en) * | 2001-03-30 | 2002-10-08 | Japan Organo Co Ltd | Crystallization reaction apparatus provided with means for vaporizing/concentrating treated water |
| JP4669624B2 (en) * | 2001-03-30 | 2011-04-13 | オルガノ株式会社 | Crystallization reactor equipped with evaporative concentration means of treated water |
| JP2015062897A (en) * | 2002-11-13 | 2015-04-09 | デカ・プロダクツ・リミテッド・パートナーシップ | Distillation method with vapor pressurization |
| JP2006305541A (en) * | 2005-03-30 | 2006-11-09 | Sasakura Engineering Co Ltd | Method and apparatus for treating waste water containing calcium and sulfuric acid |
| CN103101989A (en) * | 2013-02-05 | 2013-05-15 | 双良节能系统股份有限公司 | Self-cleaning high-salt wastewater evaporative crystallization device |
| CN103101989B (en) * | 2013-02-05 | 2014-07-30 | 双良节能系统股份有限公司 | Self-cleaning high-salt wastewater evaporative crystallization device |
| JP2018130717A (en) * | 2017-02-16 | 2018-08-23 | 一般財団法人電力中央研究所 | Processing method and system for treatment of desulfurization waste water |
| CN111003870A (en) * | 2019-12-27 | 2020-04-14 | 攀钢集团西昌钢钒有限公司 | Desulfurization wastewater treatment method and treatment device |
| CN114835321A (en) * | 2022-04-14 | 2022-08-02 | 光大环保技术研究院（南京）有限公司 | Evaporation system |
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