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JPS6242738Y2 - - Google Patents

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Publication number
JPS6242738Y2
JPS6242738Y2 JP15003482U JP15003482U JPS6242738Y2 JP S6242738 Y2 JPS6242738 Y2 JP S6242738Y2 JP 15003482 U JP15003482 U JP 15003482U JP 15003482 U JP15003482 U JP 15003482U JP S6242738 Y2 JPS6242738 Y2 JP S6242738Y2
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Japan
Prior art keywords
tower
solid
slurry
liquid
gypsum
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Expired
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JP15003482U
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Japanese (ja)
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JPS5953833U (en
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Publication of JPS5953833U publication Critical patent/JPS5953833U/en
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  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Description

【考案の詳細な説明】 本考案は湿式脱硫装置に係り、特に石膏を分離
後に得られる過水中のカルシウムを高効率に除
去するのに好適な湿式脱硫装置に関する。
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wet desulfurization device, and more particularly to a wet desulfurization device suitable for highly efficiently removing calcium from perwater obtained after separating gypsum.

カルシウム系吸収剤を用いる脱硫プロセスにお
いて、ボイラー等からの排ガスは除塵塔で除塵と
同時に冷却され、次いで吸収塔に導かれ吸収塔循
環スラリーにより排ガス中の硫黄酸化物が吸収除
去され、クリーンガスとして排出される。吸収塔
で反応、生成したCaSO3・1/2H2O、CaSO4
2H2O及び未反応CaCO3等からなるスラリーは吸
収塔における硫黄酸化物の量に応じて抜き出され
て反応槽に送られる。反応槽ではスラリー中の未
反応CaCO3を硫酸で石膏とし、さらにスラリー
のPHを4.5〜5として酸化塔でスラリー中の
CaSO3・1/2H2Oが空気によつて酸化され石膏と
なる。このようにしてスラリー中の固形物はすべ
て石膏スラリーとなり、シツクナーで固液分離さ
れる。シツクナーの上澄液(過水)は除塵塔、
吸収塔及び石灰石スラリー槽の補給水として再利
用される。
In the desulfurization process using a calcium-based absorbent, exhaust gas from a boiler, etc. is cooled at the same time as dust removal in a dust removal tower, and then led to an absorption tower where sulfur oxides in the exhaust gas are absorbed and removed by the absorption tower circulation slurry, and it is converted into clean gas. It is discharged. CaSO 3 1/2H 2 O, CaSO 4
A slurry consisting of 2H 2 O, unreacted CaCO 3 , etc. is extracted according to the amount of sulfur oxide in the absorption tower and sent to the reaction tank. In the reaction tank, unreacted CaCO 3 in the slurry is made into gypsum with sulfuric acid, and the pH of the slurry is adjusted to 4.5 to 5, and the slurry is converted into gypsum in the oxidation tower.
CaSO 3 1/2H 2 O is oxidized by air and becomes gypsum. In this way, all the solids in the slurry become gypsum slurry, which is separated into solid and liquid using a thickener. The supernatant liquid (super water) of the thickner is stored in a dust removal tower.
It is reused as make-up water for the absorption tower and limestone slurry tank.

しかし、この過水は石膏の飽和あるいは過飽
和溶液であり、PH変動により、あるいは冷却、除
塵工程での水の蒸発により石膏が析出する。この
際、石膏の一部は塔、タンク、配管等に付着して
スケールとなる。このトラブルを防止するため
に、過水にNaCO3あるいはNa2CO3とNaOHを
添加して次式によりCa2+をCaCO3として沈澱除
去することができる。
However, this perhydration is a saturated or supersaturated solution of gypsum, and gypsum precipitates due to pH fluctuations or evaporation of water during cooling and dust removal processes. At this time, some of the gypsum adheres to towers, tanks, piping, etc. and becomes scale. In order to prevent this trouble, Ca 2+ can be precipitated and removed as CaCO 3 by adding NaCO 3 or Na 2 CO 3 and NaOH to perhydrous water using the following formula.

Ca2++SO4 2-+Na2CO3=CaCO3↓2Na+
SO4 2- しかし、本沈澱反応の速度は各種因子によつて
影響され、特にNaCO3/Ca2+モル比、PH及び反
応温度等に留意して操作しなければ、CaCO3
主体とするスケールの発生という新たな問題が生
じる。
Ca 2+ +SO 4 2- +Na 2 CO 3 =CaCO 3 ↓2Na + +
SO 4 2- However, the rate of this precipitation reaction is affected by various factors, and unless the operation is performed with particular attention to the NaCO 3 /Ca 2+ molar ratio, PH, and reaction temperature, CaCO 3 will be the main component. A new problem arises: scale generation.

また従来、Ca2+の除去法及びスケーリング防
止法が提案されているが、この種の化学反応操作
においては、沈澱剤を添加した後は程度の差はあ
れ、Ca2+の過飽和溶液となり、絶えずスケール
を生ずる可能性を有している。
In addition, methods for removing Ca 2+ and preventing scaling have been proposed in the past, but in this type of chemical reaction operation, after adding a precipitant, the solution becomes a supersaturated solution of Ca 2+ to varying degrees. It has the potential to constantly scale.

本考案の目的は、石膏回収工程時に生成する
過水中のCa2+を除去して得られる軟水化処理水
を脱硫プロセスで有効利用できる湿式脱硫装置を
提供することにある。
An object of the present invention is to provide a wet desulfurization device that can effectively utilize softened water obtained by removing Ca 2+ from superhydrous water generated during the gypsum recovery process in the desulfurization process.

要するに本考案は、石膏回収時工程時に生成す
る過水中のCa2+を調整タンクにて亜硫酸塩と
し、固液分離槽にて亜硫酸塩を沈澱分離した後、
清澄液中の亜硫酸イオンの一部又は全量を酸化塔
にて硫酸イオンに酸化し、得られた処理水を脱硫
装置内の少なくともいずれかの装置類に補給水と
して供給するようにしたものである。
In short, the present invention converts Ca 2+ in superhydrous water generated during the gypsum recovery process into sulfite in the adjustment tank, and separates the sulfite by precipitation in the solid-liquid separation tank.
Part or all of the sulfite ions in the clarified liquid are oxidized to sulfate ions in an oxidation tower, and the resulting treated water is supplied as make-up water to at least one of the devices in the desulfurization equipment. .

以下、添付図面に基いて本考案の実施例を説明
する。
Embodiments of the present invention will be described below with reference to the accompanying drawings.

第1図において、ボイラー等からの排ガス11
は除塵塔1に導かれ、除塵塔循環液101によつ
て除塵と同時に冷却される。この除塵、冷却され
た排ガス12は吸収塔2に導かれ、吸収塔循環ス
ラリー105により硫黄酸化物が吸収、除去され
て、クリーンガス13として排出される。除塵塔
1からは煤塵を含有する除塵塔循環液101の一
部が抜き出され、脱硫排水102として排水処理
装置Aに送られる。吸収塔2には硫黄酸化物の吸
収量に応じて石灰石スラリー103が石灰石スラ
リー槽3から供給される。また、吸収塔2で反
応、生成したCaSO3・1/2H2O、CaSO4・2H2O及
び未反応CaCO3等からなるスラリー104は吸
収塔2での硫黄酸化物の量に応じてスラリー10
6として抜き出されて反応槽4に送られる。反応
槽4ではスラリー106中の未反応CaCO3を硫
酸15で石膏とし、さらにスラリーのPHを4.5〜
5として酸化塔5に送られる。酸化塔5では、ス
ラリー107中のCaSO3・1/2H2Oが空気によつ
て酸化されて石膏となり、スラリー中の固形物は
すべて石膏スラリー108となり、シツクナー6
で固液分離される。濃縮スラリー109は脱水機
7で脱水され、石膏110となる。脱水排液11
1はシツクナー6に戻される。
In Figure 1, exhaust gas 11 from a boiler etc.
is led to the dust removal tower 1, and is cooled by the dust removal tower circulation liquid 101 at the same time as dust removal. The dust-removed and cooled exhaust gas 12 is led to the absorption tower 2, where sulfur oxides are absorbed and removed by the absorption tower circulation slurry 105 and discharged as clean gas 13. A part of the dust removing tower circulation liquid 101 containing soot and dust is extracted from the dust removing tower 1 and sent to the waste water treatment device A as desulfurization waste water 102 . Limestone slurry 103 is supplied to the absorption tower 2 from the limestone slurry tank 3 according to the amount of sulfur oxide absorbed. In addition, the slurry 104 consisting of CaSO 3 1/2H 2 O, CaSO 4 2H 2 O, unreacted CaCO 3 , etc. reacted and generated in the absorption tower 2 is converted into a slurry according to the amount of sulfur oxide in the absorption tower 2. 10
6 and sent to the reaction tank 4. In reaction tank 4, unreacted CaCO 3 in slurry 106 is made into gypsum with sulfuric acid 15, and the pH of the slurry is further adjusted to 4.5 to 4.5.
5 is sent to the oxidation tower 5. In the oxidation tower 5, CaSO 3 1/2H 2 O in the slurry 107 is oxidized by air to become gypsum, and all solids in the slurry become gypsum slurry 108,
solid-liquid separation. The concentrated slurry 109 is dehydrated by a dehydrator 7 to become gypsum 110. Dehydrated liquid 11
1 is returned to the thickener 6.

シツクナー6の上澄液(過水)112は過
水調整タンク81に導かれ、ここでPH6以上にお
いて亜硫酸塩116が添加される。亜硫酸塩とし
てはナトリウム、カリウム、アンモニウム、マグ
ネシウム等の塩が使用可能であり、また亜硫酸塩
の代りに重亜硫酸塩、ピロ亜硫酸塩または亜硫酸
ガスを添加あるいは吹き込んでも全く同一の効果
が得られる。液のPHは6以上、好ましくは7以上
が推奨されるが、これはPH6以下では亜硫酸カル
シウムの沈澱が生じないからである。このPH調整
のための添加される物質としてはナトリウム、カ
リウム、マグネシウム、アンモニウム等の酸化
物、水酸化物あるいは炭酸塩が使用可能である
が、経済性を加味すると水酸化ナトリウムあるい
は炭酸ナトリウムを用いるのが望ましい。なお、
苛性アルカリ117を添加してPHを10以上とし、
Ca2+と共存するMg2+を同時に水酸化物として沈
澱させることもできる。また、過水調整タンク
81ではCa2+の沈澱除去剤である亜硫酸塩等と
ともに凝集剤118を添加してCaSO3・1/2H2O
の沈澱反応を促進させることもできる。なお、こ
の凝集剤の添加は過水調整タンク81と別途に
凝集剤添加槽82を設けて、ここで行うこともで
きる。凝集沈澱に適したフロツクが形成された処
理水802は固体分離装置83に送られ、沈降分
離、過、遠心分離などの方法により固液分離さ
れて清澄液803となる。清澄液は酸化塔84に
送られ、含有される亜硫酸イオンの一部または全
量が硫酸イオンに酸化されたのち、処理水タンク
85に貯えられる。
The supernatant liquid (super water) 112 of the thickener 6 is led to a super water adjustment tank 81, where sulfite 116 is added at a pH of 6 or higher. As the sulfite, salts such as sodium, potassium, ammonium, and magnesium can be used, and the same effect can be obtained by adding or blowing bisulfite, pyrosulfite, or sulfur dioxide gas instead of sulfite. It is recommended that the pH of the liquid be 6 or higher, preferably 7 or higher, because calcium sulfite will not precipitate if the pH is lower than 6. Oxides, hydroxides, or carbonates of sodium, potassium, magnesium, ammonium, etc. can be used as substances to be added for this pH adjustment, but sodium hydroxide or sodium carbonate is used in consideration of economic efficiency. is desirable. In addition,
Add caustic alkali 117 to make the pH 10 or more,
Mg 2+ coexisting with Ca 2+ can also be simultaneously precipitated as a hydroxide. In addition, in the overwater adjustment tank 81, a flocculant 118 is added together with sulfite, etc., which is a Ca 2+ precipitate remover, and CaSO 3 1/2H 2 O is added.
It is also possible to promote the precipitation reaction. Note that this addition of the flocculant can also be carried out by providing a flocculant addition tank 82 separately from the overwater adjustment tank 81. The treated water 802 in which flocs suitable for coagulation and sedimentation have been formed is sent to a solid separator 83, where it is separated into solid and liquid by a method such as sedimentation, filtration, or centrifugation to become a clear liquid 803. The clarified liquid is sent to an oxidation tower 84, where some or all of the sulfite ions contained therein are oxidized to sulfate ions, and then stored in a treated water tank 85.

酸化塔84における亜硫酸イオンの酸化剤11
9としては、空気、酸素、オゾン、過酸化水素、
塩素、臭素、次亜塩素酸、ヨウ素、酸化窒素等の
使用が可能であるが、空気あるいは過酸化水素に
よる方法が簡便である。
Oxidizing agent 11 for sulfite ions in the oxidizing tower 84
9 includes air, oxygen, ozone, hydrogen peroxide,
Although it is possible to use chlorine, bromine, hypochlorous acid, iodine, nitrogen oxide, etc., it is easier to use air or hydrogen peroxide.

処理水タンク85の処理水は処理水供給ライン
を経て除塵塔1、吸収塔2および石灰石スラリー
槽3における補給水113,114,115とし
て利用される。なお、処理水85の処理水は除塵
塔1、吸収塔2および石灰石スラリー槽3のいず
れかに補給水として利用してもよい。
The treated water in the treated water tank 85 is used as make-up water 113, 114, 115 in the dust removal tower 1, absorption tower 2, and limestone slurry tank 3 through the treated water supply line. Note that the treated water 85 may be used as makeup water for any of the dust removal tower 1, absorption tower 2, and limestone slurry tank 3.

次に本考案における作用を第2図に示す平衡溶
解度曲線から説明する。第2図は溶解度積から求
めたCaSO3、CaSO4及びCaSO4の平衡溶解度曲線
を示すが、同一のPH及びアニオン濃度に対する溶
解度はCaSO3<CaCO3であり、理論的には軟水
化剤としてはNa2CO3よりもむしろNa2SO3の方が
効果的であることがわかる。しかし、一般のいず
れの軟水化法においてもCa塩の析出速度が小さ
いためにスケール発生というトラブルが生ずる。
本考案においては、Caの沈澱槽以後の工程にお
けるスケール生成防止に対して極めて有効である
が、その基本原理は次の通りである:第2図から
明らかなようにPH>5.4におけるCaの溶解度は
CaSO4>CaSO3である。従つて、一旦Caを亜硫
酸塩として沈澱除去した後、溶液中の亜硫酸イオ
ンを硫酸イオンに酸化すれば、もはやCaSO3・1/
2H2Oの沈澱は生じないことになる。
Next, the action of the present invention will be explained using the equilibrium solubility curve shown in FIG. Figure 2 shows the equilibrium solubility curves of CaSO 3 , CaSO 4 and CaSO 4 calculated from the solubility product. It can be seen that Na 2 SO 3 is more effective than Na 2 CO 3 . However, in all general water softening methods, the problem of scale generation occurs because the precipitation rate of Ca salt is slow.
The present invention is extremely effective in preventing scale formation in the steps after the Ca precipitation tank, and its basic principle is as follows: As is clear from Figure 2, the solubility of Ca at pH > 5.4. teeth
CaSO 4 >CaSO 3 . Therefore, once Ca is precipitated and removed as sulfite and the sulfite ions in the solution are oxidized to sulfate ions, CaSO 3.1 /
No precipitation of 2H 2 O will occur.

このように本考案において、湿式脱硫における
プロセス水の処理に際し、Ca除去後に沈澱剤を
酸化処理して再びCaの安定溶液とし、スケール
発生の可能性を消失させるものである。
As described above, in the present invention, when treating process water in wet desulfurization, after removing Ca, the precipitant is oxidized to become a stable solution of Ca again, thereby eliminating the possibility of scale generation.

実施例 1 次の組成を持つ石灰−石膏法脱硫プロセス排水
250mlを撹拌機付のガラス製容器に入れ、40℃の
水浴中に浸漬した:Ca2+498ppm、
Mg2+406ppm、Na+2710ppm、SO4 2-6010ppm、
Cl-1700ppm、PH6.5。所定温度に達した時点で所
定量のNa2SO3を上記のプロセス排水に添加して
撹拌を続けながら溶液中のCa2+濃度を追跡した
ところ、第3図の結果が得られた。
Example 1 Lime-gypsum desulfurization process wastewater with the following composition:
250 ml was placed in a glass container with a stirrer and immersed in a water bath at 40 °C: Ca 2+ 498 ppm,
Mg2+ 406ppm , Na + 2710ppm, SO42- 6010ppm,
Cl - 1700ppm, PH6.5. When a predetermined amount of Na 2 SO 3 was added to the above process wastewater when a predetermined temperature was reached and the Ca 2+ concentration in the solution was monitored while stirring, the results shown in FIG. 3 were obtained.

次にNa2SO3をCa2+に対し2倍モル量添加して
20分間撹拌した時のCa2+濃度は69ppmである。
この溶液を過してCaSO3・1/2H2Oを除去した
後、30%H2O2水を0.1%添加し、液を放置した
ところ、以後におけるCa塩の沈澱生成は認めら
れなかつた。
Next, add twice the molar amount of Na 2 SO 3 to Ca 2+ .
The Ca 2+ concentration after stirring for 20 minutes was 69 ppm.
After filtering this solution to remove CaSO 3 1/2H 2 O, 0.1% of 30% H 2 O 2 water was added and the solution was left to stand, but no Ca salt precipitation was observed thereafter. .

実施例 2 実施例1の操作においてH2O2添加の代りに空
気の吹込みを10分間行つたところ、実施例1と同
様に酸化操作後のCa塩の沈澱生成は認められな
かつた。
Example 2 In the operation of Example 1, air was blown for 10 minutes instead of adding H 2 O 2 . As in Example 1, no Ca salt precipitation was observed after the oxidation operation.

以上のように本考案によれば、脱硫排液中の
Ca2+を亜硫酸塩として沈澱除去し、沈澱反応終
了後に沈澱剤である亜硫酸イオンを硫酸イオンに
酸化するものであるので、脱硫排液中のCaCO3
の(過)飽和溶液がCaSO4の不飽和溶液に移行す
るのでCa塩からなるスケールの生成を防止でき
る。
As described above, according to the present invention, the desulfurization wastewater is
Since Ca 2+ is precipitated and removed as sulfite, and after the precipitation reaction is completed, sulfite ions, which are precipitants, are oxidized to sulfate ions, CaCO 3 in the desulfurization wastewater is removed.
Since the (super)saturated solution of CaSO 4 is transferred to an unsaturated solution of CaSO 4 , the formation of scale consisting of Ca salt can be prevented.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は本考案の一例を示す構成図、第2図は
Ca塩の溶解度曲線、第3図は脱硫プロセス排水
(過水)をNa2SO3により軟水化したときのCa2+
濃度を示す図である。 1……除塵塔、2……吸収塔、3……石灰石ス
ラリー槽、4……反応槽、5……酸化塔、6……
シツクナー、7……脱水機、81……過水調整
タンク、82……凝集剤添加槽、83……固体分
離装置、84……酸化塔、85……処理水タン
ク。
Figure 1 is a configuration diagram showing an example of the present invention, and Figure 2 is a block diagram showing an example of the present invention.
Solubility curve of Ca salt, Figure 3 shows Ca 2+ when desulfurization process wastewater (superwater) is softened with Na 2 SO 3
It is a figure showing concentration. 1... Dust removal tower, 2... Absorption tower, 3... Limestone slurry tank, 4... Reaction tank, 5... Oxidation tower, 6...
Thickener, 7... Dehydrator, 81... Superhydration adjustment tank, 82... Coagulant addition tank, 83... Solid separation device, 84... Oxidation tower, 85... Treated water tank.

Claims (1)

【実用新案登録請求の範囲】[Scope of utility model registration request] 硫黄酸化物含有排ガスを冷却除塵する除塵塔
と、この除塵塔からのガスをカルシウムを含む液
またはスラリーと接触させて脱硫する吸収塔と、
この吸収塔から抜き出されたスラリーを硫酸によ
り石膏とする反応槽と、この反応槽から抜き出さ
れたスラリー中の亜硫酸塩を酸化して石膏とする
酸化塔と、この酸化塔からのスラリーを固液分離
する固液分離装置と、を備えた湿式脱硫装置にお
いて、前記固液分離装置で得られる溶液中のCa
の一部又は全量を亜硫酸塩とするための調整タン
クと、この調整タンクで得られた処理水を固液分
離する固液分離装置と、この固液分離装置で得ら
れる清澄液中の亜硫酸イオンの一部又は全量を硫
酸イオンに酸化する酸化塔と、この酸化塔で得ら
れた処理水を脱硫装置内の少なくともいずれかの
装置類に補給水として供給する処理水供給ライン
とを設けたことを特徴とする湿式脱硫装置。
a dust removal tower that cools and removes dust from exhaust gas containing sulfur oxides; an absorption tower that desulfurizes the gas from the dust removal tower by contacting it with a liquid or slurry containing calcium;
A reaction tank that converts the slurry extracted from the absorption tower into gypsum using sulfuric acid, an oxidation tower that oxidizes the sulfite in the slurry extracted from this reaction tank to create gypsum, and an oxidation tower that converts the slurry from this oxidation tower into gypsum. In a wet desulfurization apparatus equipped with a solid-liquid separator that performs solid-liquid separation, Ca in the solution obtained by the solid-liquid separator is
An adjustment tank for converting part or all of the amount of water into sulfite, a solid-liquid separator that separates the treated water obtained in this adjustment tank from solid to liquid, and sulfite ions in the clear liquid obtained by this solid-liquid separator. An oxidation tower that oxidizes some or all of the oxidation tower into sulfate ions, and a treated water supply line that supplies the treated water obtained from this oxidation tower to at least one of the devices in the desulfurization equipment as make-up water. Wet desulfurization equipment featuring:
JP15003482U 1982-10-01 1982-10-01 Wet desulfurization equipment Granted JPS5953833U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15003482U JPS5953833U (en) 1982-10-01 1982-10-01 Wet desulfurization equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15003482U JPS5953833U (en) 1982-10-01 1982-10-01 Wet desulfurization equipment

Publications (2)

Publication Number Publication Date
JPS5953833U JPS5953833U (en) 1984-04-09
JPS6242738Y2 true JPS6242738Y2 (en) 1987-11-02

Family

ID=30332872

Family Applications (1)

Application Number Title Priority Date Filing Date
JP15003482U Granted JPS5953833U (en) 1982-10-01 1982-10-01 Wet desulfurization equipment

Country Status (1)

Country Link
JP (1) JPS5953833U (en)

Also Published As

Publication number Publication date
JPS5953833U (en) 1984-04-09

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