JP3174665B2 - Flue gas desulfurization method - Google Patents
Flue gas desulfurization methodInfo
- Publication number
- JP3174665B2 JP3174665B2 JP15184093A JP15184093A JP3174665B2 JP 3174665 B2 JP3174665 B2 JP 3174665B2 JP 15184093 A JP15184093 A JP 15184093A JP 15184093 A JP15184093 A JP 15184093A JP 3174665 B2 JP3174665 B2 JP 3174665B2
- Authority
- JP
- Japan
- Prior art keywords
- compound
- absorbing solution
- sulfate
- flue gas
- concentration
- 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
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- Treating Waste Gases (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は排煙脱硫方法の改良に関
し、特にジチオン酸の生成を抑制する排煙脱硫方法に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a flue gas desulfurization method, and more particularly to a flue gas desulfurization method for suppressing the formation of dithionic acid.
【０００２】[0002]
【従来の技術】硫黄酸化物を含む排ガスを対象に湿式石
灰石膏法による排煙脱硫を実施する場合、排ガス中の硫
黄酸化物は炭酸カルシウムを含有する吸収液と接触し、
以下の反応により吸収される。 ＳＯ2 ＋ Ｈ2 Ｏ → Ｈ2 ＳＯ3 Ｈ2 ＳＯ3 ＋ＣａＣＯ3 → ＣａＳＯ3 ＋Ｈ2 ＣＯ
3 生成した亜硫酸塩は下式のように排ガス中の酸素あるい
は系外から供給される空気または酸素により酸化され硫
酸塩となるが、一部はジチオン酸イオンとして生成する
といわれている。 ２Ｈ2 ＳＯ3 - ＋Ｏ2 → Ｈ2 ＳＯ4 - ＋Ｓ2 Ｏ6 2-
＋Ｈ2 Ｏ 湿式石灰石膏法排煙脱硫方法においては、吸収液中の不
純物の蓄積を防止するため一部を排水として系外に排出
する。この際、排水の放流基準として化学的酸素要求量
（ＣＯＤ）の制限値が定められている。2. Description of the Related Art When performing flue gas desulfurization by wet lime-gypsum method on exhaust gas containing sulfur oxide, the sulfur oxide in the exhaust gas comes into contact with an absorbent containing calcium carbonate,
It is absorbed by the following reaction. SO 2 + H 2 O → H 2 SO 3 H 2 SO 3 + CaCO 3 → CaSO 3 + H 2 CO
(3) The generated sulfite is oxidized by oxygen in the exhaust gas or air or oxygen supplied from outside the system to form a sulfate as shown in the following formula, but it is said that a part of the sulfite is formed as dithionate ion. 2H 2 SO 3 - + O 2 → H 2 SO 4 - + S 2 O 6 2-
In the + H 2 O wet lime gypsum flue gas desulfurization method, a part of the solution is discharged to the outside as wastewater in order to prevent accumulation of impurities in the absorbent. At this time, a limit value of the chemical oxygen demand (COD) is set as a discharge standard of the wastewater.
【０００３】亜硫酸の酸化により生成するジチオン酸は
ＣＯＤとして検出されるため、ジチオン酸の生成を抑制
する必要があるが、冷却・除じん塔の省略などによる吸
収液のイオン強度が高い場合にはジチオン酸の生成は抑
制されず、所定の水質基準を満足するため、ジチオン酸
処理設備が必要であり、コストの増大につながるという
問題を有する。[0003] Since dithionic acid produced by the oxidation of sulfurous acid is detected as COD, it is necessary to suppress the production of dithionic acid. However, if the ionic strength of the absorbing solution is high due to the omission of a cooling / dust removing tower, etc. Since the production of dithionic acid is not suppressed and a predetermined water quality standard is satisfied, a dithionic acid treatment facility is required, which leads to an increase in cost.
【０００４】[0004]
【発明が解決しようとする課題】上記したように、従来
技術では硫黄酸化物を含む排ガスをカルシウム化合物を
含有する吸収液で処理する方法において、冷却・除じん
塔の省略などによる吸収液のイオン強度が高い場合には
ジチオン酸の生成は抑制されず、所定の水質基準を満足
するためジチオン酸処理設備が必要であり、コストの増
大につながるという問題があった。As described above, in the prior art, in a method of treating an exhaust gas containing a sulfur oxide with an absorbing solution containing a calcium compound, the ionizing of the absorbing solution by omitting a cooling / dusting tower is performed. When the strength is high, the production of dithionic acid is not suppressed, and a dithionic acid treatment facility is required to satisfy a predetermined water quality standard, resulting in a problem that the cost is increased.
【０００５】本発明は上記技術水準に鑑み、従来技術及
び従来技術より考えられる方法の不具合を解消し得るジ
チオン酸の生成抑制を可能とした排煙脱硫方法を提供し
ようとするものである。The present invention has been made in view of the above-mentioned state of the art, and an object of the present invention is to provide a flue gas desulfurization method capable of suppressing the production of dithionic acid capable of solving the problems of the prior art and the methods considered from the prior art.
【０００６】[0006]
【課題を解決するための手段】上記のような状況におい
て、本発明者らは硫黄酸化物を含む排ガスをカルシウム
化合物を含有する吸収液で処理する方法において、冷却
・除じん塔の省略などによる吸収液のイオン強度が高い
場合には、ジチオン酸の生成を抑制するために添加剤と
してナトリウム化合物、カリウム化合物、マグネシウム
化合物及びアンモニウム化合物よりなる群の中から選ば
れた少なくとも１種類の化合物を吸収液に添加する方法
を見い出し、この知見に基づいて本発明を完成するに至
った。In the above situation, the present inventors have proposed a method of treating an exhaust gas containing sulfur oxides with an absorbent containing a calcium compound by omitting a cooling / dust column. When the ionic strength of the absorbing solution is high, at least one compound selected from the group consisting of a sodium compound, a potassium compound, a magnesium compound and an ammonium compound is absorbed as an additive to suppress the formation of dithionic acid. The inventors have found a method of adding the compound to the liquid, and have completed the present invention based on this finding.
【０００７】すなわち、本発明は硫黄酸化物を含む排ガ
スをカルシウム化合物を含有する吸収液で処理する方法
において、吸収液中の硫酸塩（以下、硫酸、硫酸水素塩
及び硫酸塩を含めて硫酸塩と総称する）濃度を検出した
信号と、硫酸塩濃度設定値との偏差信号により、ナトリ
ウム化合物、カリウム化合物、マグネシウム化合物及び
アンモニウム化合物よりなる群の中から選ばれた少なく
とも１種類の化合物を該吸収液に添加することを特徴と
する排煙脱硫方法である。That is, the present invention relates to a method for treating an exhaust gas containing sulfur oxides with an absorbing solution containing a calcium compound, wherein the sulfate (hereinafter referred to as sulfuric acid, hydrogen sulfate and sulfate including sulfuric acid) in the absorbing solution is used. Absorbed at least one compound selected from the group consisting of a sodium compound, a potassium compound, a magnesium compound and an ammonium compound, based on a deviation signal between the concentration detection signal and the sulfate concentration set value. It is a flue gas desulfurization method characterized by being added to a liquid.
【０００８】本発明に使用される添加剤としては、水酸
化ナトリウム、炭酸ナトリウム、硫酸ナトリウムのよう
なナトリウム化合物、水酸化カリウム、炭酸カリウム、
硫酸カリウムのようなカリウム化合物、水酸化マグネシ
ウム、炭酸マグネシウム、硫酸マグネシウムのようなマ
グネシウム化合物及びアンモニア、硫酸アンモニウムの
ようなアンモニウム化合物などがあげられる。さらに、
硫酸塩濃度検出器としてはイオンクロマトグラフなどが
使用可能である。The additives used in the present invention include sodium compounds such as sodium hydroxide, sodium carbonate and sodium sulfate, potassium hydroxide, potassium carbonate, and the like.
Examples include potassium compounds such as potassium sulfate, magnesium compounds such as magnesium hydroxide, magnesium carbonate and magnesium sulfate, and ammonium compounds such as ammonia and ammonium sulfate. further,
An ion chromatograph or the like can be used as the sulfate concentration detector.
【０００９】[0009]
【作用】本発明者らは冷却・除じん塔の省略により吸収
液中に塩化物などを多量に含みイオン強度が高い場合
に、ジチオン酸の生成が抑制されない原因に関して鋭意
検討した結果、吸収された硫黄酸化物のジチオン酸への
転化率は吸収液中の硫酸塩濃度依存性が大きく、硫酸塩
濃度が低いほど転化率は高いことを明らかにした。さら
に、吸収液中の硫酸塩濃度が低い場合のジチオン酸の生
成抑制方法に関して検討を行い、吸収液中の硫酸塩濃度
を検出した信号と、硫酸塩濃度設定値との偏差信号によ
りナトリウム化合物、カリウム化合物、マグネシウム化
合物及びアンモニウム化合物よりなる群の中から選ばれ
た少なくとも１種類の化合物を添加することにより吸収
液中の硫酸塩濃度を増加させジチオン酸の生成を抑制し
得るようにした。The present inventors have conducted intensive studies on the reason why the formation of dithionic acid is not suppressed when the absorption liquid contains a large amount of chlorides and the like and the ionic strength is high due to the omission of the cooling and dust removal tower. It was clarified that the conversion of sulfur oxides to dithionic acid was highly dependent on the sulfate concentration in the absorbing solution, and that the lower the sulfate concentration, the higher the conversion. Furthermore, a method for suppressing the production of dithionic acid when the sulfate concentration in the absorbing solution is low was studied, and a signal indicating the sulfate concentration in the absorbing solution and a deviation signal between the sulfate concentration setting value were used to determine the sodium compound, By adding at least one compound selected from the group consisting of a potassium compound, a magnesium compound and an ammonium compound, the concentration of sulfate in the absorbing solution can be increased and the formation of dithionic acid can be suppressed.
【００１０】[0010]
【実施例】本発明の一実施例を図１によって説明する。
図１は燃焼排ガスを炭酸カルシウムを含有する吸収液に
添加剤の一例として硫酸マグネシウムを添加し、湿式石
灰石膏法排煙脱硫方法によって処理した場合の一実施例
を示している。燃焼排ガス２と吸収塔１を循環する吸収
液３とを気液接触させ、燃焼排ガス２中の硫黄酸化物を
吸収・分離する。硫黄酸化物が除去された燃焼排ガスは
清浄ガス４となって排出される。吸収液３に吸収された
硫黄酸化物は燃焼排ガス中の酸素で酸化されて石膏とな
る。燃焼排ガス２中の硫黄酸化物の濃度が高いか、酸素
濃度が低いなどの理由により酸化が充分でない場合に
は、吸収塔液室５に空気６を供給する場合もある。FIG. 1 shows an embodiment of the present invention.
FIG. 1 shows an embodiment in which magnesium sulfate is added as an example of an additive to an absorption liquid containing calcium carbonate to a flue gas and the mixture is treated by a wet lime gypsum method and a flue gas desulfurization method. The flue gas 2 and the absorbing liquid 3 circulating in the absorption tower 1 are brought into gas-liquid contact to absorb and separate sulfur oxides in the flue gas 2. The combustion exhaust gas from which the sulfur oxides have been removed is discharged as a clean gas 4. The sulfur oxides absorbed by the absorbing liquid 3 are oxidized by oxygen in the combustion exhaust gas to form gypsum. When the oxidation is not sufficient due to a high concentration of sulfur oxide in the combustion exhaust gas 2 or a low oxygen concentration, the air 6 may be supplied to the liquid chamber 5 of the absorption tower.
【００１１】生成した石膏は溶解度が小さいため吸収液
中で析出して固体となる。石膏を含んだ吸収液の一部は
抜き出しライン７を介して吸収塔１より排出され、固液
分離機８で石膏９とろ液１０に分離され、ろ液１０の一
部は原料調整槽１１へ送られ、残部は排水１２として系
外に排出される。原料調整槽１１で炭酸カルシウムが供
給され、硫酸塩濃度検出器１３により吸収液中の硫酸塩
濃度を検出した信号と硫酸塩濃度設定値との偏差信号に
より調節弁１４の開度を変えることで硫酸マグネシウム
を含む液が添加され、再び吸収塔へ戻される。硫酸マグ
ネシウムは原料調整槽で添加される必然性はなく、吸収
塔に直接添加しても問題ないが、添加装置の簡便さから
この実施例では原料調整槽１１に添加した。Since the formed gypsum has low solubility, it precipitates in the absorbing solution and becomes a solid. Part of the absorbent containing gypsum is discharged from the absorption tower 1 through a withdrawal line 7, separated into gypsum 9 and filtrate 10 by a solid-liquid separator 8, and part of the filtrate 10 is sent to a raw material adjusting tank 11. The waste is sent to the outside as waste water 12. Calcium carbonate is supplied in the raw material adjusting tank 11, and the opening of the control valve 14 is changed by a deviation signal between a signal in which the sulfate concentration is detected by the sulfate concentration detector 13 and a sulfate concentration set value. A liquid containing magnesium sulfate is added and returned to the absorption tower. Magnesium sulfate is not necessarily added in the raw material adjusting tank, and there is no problem if it is directly added to the absorption tower. However, in this embodiment, magnesium sulfate was added to the raw material adjusting tank 11 because of the simple addition apparatus.
【００１２】以下に一実施例の運転状態の一例を示す。 （１）吸収塔条件 入口ガス量 ： ２００ｍ
3 Ｎ／ｈ（ｄｒｙ） 入口ＳＯ2 濃度 ： １０００ｐｐｍ（ｄｒｙ） （２）吸収塔 吸収液循環流量 ： ３．９ｍ
3 ／ｈ 吸収塔液室容量 ： ０．２ｍ3 運転ｐＨ ： ６．０ 吸収液中硫酸塩濃度： ５０ｍｍｏｌ／リットル 上記の装置及び運転状態において、排ガスからの硫黄酸
化物の除去率は９６％以上であった。さらに、排水３リ
ットル／ｍｉｎ中のジチオン酸濃度は２０ｍｇ／リット
ルであった。An example of the operating state of the embodiment will be described below. (1) Absorption tower conditions Inlet gas volume: 200 m
3 N / h (dry) Inlet SO 2 concentration: 1000 ppm (dry) (2) Absorption tower Absorbing liquid circulation flow rate: 3.9 m
3 / h absorption tower fluid chamber capacity: 0.2 m 3 operating pH: 6.0 absorbing solution sulphate concentration in the system and operating conditions of 50 mmol / l above, the removal rate of sulfur oxides from an exhaust gas over 96% Met. Further, the concentration of dithionic acid in the wastewater 3 liter / min was 20 mg / liter.
【００１３】なお、硫酸マグネシウムに代え、ナトリウ
ム化合物、カリウム化合物またはアンモニウム化合物を
使用してもほゞ同様な結果が得られた。In addition, almost the same results were obtained when a sodium compound, a potassium compound or an ammonium compound was used in place of magnesium sulfate.
【００１４】〔比較例〕炭酸カルシウムを含有する吸収
液に硫酸マグネシウムを添加せず、装置及びその他の運
転状態は実施例と同一の条件で運転した場合、吸収液中
の硫酸塩濃度は１０ｍｍｏｌ／リットルで排ガスからの
硫黄酸化物の除去率は９６％以上であった。一方、排水
３リットル／ｍｉｎ中のジチオン酸濃度は６５ｍｇ／リ
ットルと実施例の場合と比較して著しく高かった。[Comparative Example] When magnesium sulfate was not added to the absorbing solution containing calcium carbonate, and the apparatus and other operating conditions were operated under the same conditions as in the example, the sulfate concentration in the absorbing solution was 10 mmol / mol. In liters, the removal rate of sulfur oxides from the exhaust gas was 96% or more. On the other hand, the concentration of dithionic acid in the wastewater at 3 L / min was 65 mg / L, which was significantly higher than that of the example.
【００１５】[0015]
【発明の効果】以上、実施例で具体的に説明したよう
に、本発明は硫黄酸化物を含む排ガスをカルシウム化合
物を含有する吸収液で処理する方法において、吸収液中
の塩化物などの共存塩濃度が高く硫酸塩濃度が低い場合
に、吸収液中の硫酸塩濃度を検出した信号と、硫酸塩濃
度設定値との偏差信号によりナトリウム化合物、カリウ
ム化合物、マグネシウム化合物及びアンモニウム化合物
よりなる群の中から選ばれた少なくとも１種類の化合物
を該吸収液に添加する排煙脱硫方法であり、冷却・除じ
ん塔の省略による吸収液中のイオン強度が高い場合のジ
チオン酸の生成抑制を可能にした。As described above in detail in the embodiments, the present invention relates to a method for treating an exhaust gas containing a sulfur oxide with an absorbent containing a calcium compound. In the case where the salt concentration is high and the sulfate concentration is low, a signal of detecting the sulfate concentration in the absorbing solution and a deviation signal between the sulfate concentration set value and a sodium compound, a potassium compound, a magnesium compound and an ammonium compound This is a flue gas desulfurization method in which at least one compound selected from the group is added to the absorbing solution, and the production of dithionic acid can be suppressed when the ionic strength in the absorbing solution is high by omitting a cooling / dust removing tower. did.
【図１】本発明の一実施態様例の系統図。FIG. 1 is a system diagram of an embodiment of the present invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 井上 健治 広島県広島市西区観音新町四丁目６番22 号 三菱重工業株式会社 広島研究所内 (56)参考文献 特開 昭53−137871（ＪＰ，Ａ) 特開 平４−305224（ＪＰ，Ａ) 特開 平１−194929（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B01D 53/50 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kenji Inoue 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Research Institute (56) References JP-A-53-137871 (JP, A) JP-A-4-305224 (JP, A) JP-A-1-194929 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) B01D 53/50
Claims (1)
合物を含有する吸収液で処理する方法において、吸収液
中の硫酸塩濃度を検出した信号と、硫酸塩濃度設定値と
の偏差信号により、ナトリウム化合物、カリウム化合
物、マグネシウム化合物及びアンモニウム化合物よりな
る群の中から選ばれた少なくとも１種類の化合物を該吸
収液に添加することを特徴とする排煙脱硫方法。1. A method for treating an exhaust gas containing sulfur oxides with an absorbing solution containing a calcium compound, wherein sodium ions are detected by a deviation signal between a signal detecting a sulfate concentration in the absorbing solution and a sulfate concentration set value. A flue gas desulfurization method comprising adding at least one compound selected from the group consisting of a compound, a potassium compound, a magnesium compound and an ammonium compound to the absorbing solution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15184093A JP3174665B2 (en) | 1993-06-23 | 1993-06-23 | Flue gas desulfurization method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15184093A JP3174665B2 (en) | 1993-06-23 | 1993-06-23 | Flue gas desulfurization method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0716425A JPH0716425A (en) | 1995-01-20 |
| JP3174665B2 true JP3174665B2 (en) | 2001-06-11 |
Family
ID=15527447
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15184093A Expired - Fee Related JP3174665B2 (en) | 1993-06-23 | 1993-06-23 | Flue gas desulfurization method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3174665B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9321006B2 (en) | 2012-05-11 | 2016-04-26 | Alstom Technology Ltd | Oxidation control for improved flue gas desulfurization performance |
| US9321025B2 (en) | 2012-05-11 | 2016-04-26 | Alstom Technology Ltd | Oxidation control for improved flue gas desulfurization performance |
| US10919016B2 (en) | 2017-02-15 | 2021-02-16 | General Electric Technology Gmbh | Oxidation control for improved flue gas desulfurization performance |
| CN107185385A (en) * | 2017-07-07 | 2017-09-22 | 金川集团股份有限公司 | A kind of spuious flue gas during smelting wet dedusting of atm number, sulfur method |
| CN117504560A (en) * | 2023-10-17 | 2024-02-06 | 特莱泽(北京)科技有限公司 | Liquid medicine spraying equipment for treating industrial waste gas |
-
1993
- 1993-06-23 JP JP15184093A patent/JP3174665B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0716425A (en) | 1995-01-20 |
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