JP2003340238A - Wet flue gas desulfurization method and apparatus therefor - Google Patents
Wet flue gas desulfurization method and apparatus thereforInfo
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- JP2003340238A JP2003340238A JP2002150888A JP2002150888A JP2003340238A JP 2003340238 A JP2003340238 A JP 2003340238A JP 2002150888 A JP2002150888 A JP 2002150888A JP 2002150888 A JP2002150888 A JP 2002150888A JP 2003340238 A JP2003340238 A JP 2003340238A
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- Prior art keywords
- absorption liquid
- gas
- orp
- exhaust gas
- value
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- Gas Separation By Absorption (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、重質油や石炭の燃
焼排ガス等に含まれる硫黄酸化物を除去する湿式排煙脱
硫方法及びその装置に関する。さらに詳しくは、湿式排
煙脱硫装置から排出される廃水中の化学的酸素要求量
（ＣＯＤ）を低減させる方法及びその装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet flue gas desulfurization method and apparatus for removing sulfur oxides contained in combustion exhaust gas of heavy oil or coal. More particularly, it relates to a method and apparatus for reducing the chemical oxygen demand (COD) in wastewater discharged from a wet flue gas desulfurization apparatus.
【０００２】[0002]
【従来の技術】火力発電所等で重油や石炭等を燃焼して
発生する排ガス中の硫黄酸化物を除去する排煙脱硫装置
としては、吸収塔において排ガスと吸収剤スラリ（石灰
石などのカルシウム化合物よりなるもの）とを接触させ
て、排ガス中の亜硫酸ガスを吸収剤スラリに吸収し、接
触後の該スラリを酸化して固液分離することにより石膏
を副生する湿式排煙脱硫装置が広く普及している。2. Description of the Related Art A flue gas desulfurization device for removing sulfur oxides in exhaust gas generated by burning heavy oil, coal, etc. in a thermal power plant is used in an absorption tower as an exhaust gas and an absorbent slurry (calcium compound such as limestone). The wet flue gas desulfurization device that produces gypsum as a by-product by absorbing sulfurous acid gas in exhaust gas into an absorbent slurry and oxidizing the slurry after contact to solid-liquid separation is widely used. It is popular.
【０００３】この場合の排ガス中の主なる硫黄酸化物で
ある亜硫酸ガスは次の反応式で吸収液に吸収され、排ガ
ス中の酸素や外部から供給される酸素と反応し、石膏を
生成する。Sulfurous acid gas, which is the main sulfur oxide in the exhaust gas in this case, is absorbed by the absorbing solution according to the following reaction formula and reacts with oxygen in the exhaust gas and oxygen supplied from the outside to form gypsum.
【０００４】
ＳＯ2＋Ｈ2Ｏ→Ｈ+＋ＨＳＯ3 - …（１）
Ｈ+＋ＨＳＯ3 -＋１／２Ｏ2→２Ｈ+＋ＳＯ4 2- …（２）
２Ｈ+＋ＣａＣＯ3＋ＳＯ4 2-→ＣａＳＯ4＋ＣＯ2↑＋Ｈ2Ｏ
…（３）
ところで、通常は排ガス中の酸素濃度が低く、亜硫酸カ
ルシウムから石膏への酸化が充分に行われないため、系
外から酸素を含む気体を吸収液中に通気し石膏の生成を
促進させるが、酸素を含む気体の通気量が少ない場合、
未酸化の亜硫酸カルシウム濃度が増加するため、吸収剤
である炭酸カルシウムの溶解阻害、脱硫性能の低下等の
不具合を生ずる。[0004] SO 2 + H 2 O → H + + HSO 3 - ... (1) H + + HSO 3 - + 1 / 2O 2 → 2H + + SO 4 2- ... (2) 2H + + CaCO 3 + SO 4 2- → CaSO 4 + CO 2 ↑ + H 2 O (3) By the way, since the oxygen concentration in the exhaust gas is usually low and the oxidation of calcium sulfite to gypsum is not sufficiently performed, a gas containing oxygen is aerated from outside the system. It promotes the production of gypsum, but when the amount of gas containing oxygen is small,
Since the concentration of unoxidized calcium sulfite increases, problems such as inhibition of dissolution of calcium carbonate as an absorbent and deterioration of desulfurization performance occur.
【０００５】一方、亜硫酸カルシウムから石膏への転化
率を高めに維持しようとすれば、負荷変動等を考慮して
前記酸素を含む気体を過剰に供給せざるを得ず、ランニ
ングコストの増大およびＳ２Ｏ６やＳ２Ｏ８の等の過酸
化物が生成要因となり排水ＣＯＤの増大につながる。従
って、酸素を含む気体の通気流量を適正範囲に調整する
ことが必要である。On the other hand, if it is attempted to maintain a high conversion rate of calcium sulfite to gypsum, the gas containing oxygen must be supplied excessively in consideration of load fluctuations, etc., which increases running costs and increases S2O6. Peroxides, such as S2O8 and S2O8, act as a generation factor and lead to an increase in wastewater COD. Therefore, it is necessary to adjust the flow rate of the gas containing oxygen to an appropriate range.
【０００６】亜硫酸カルシウムの酸化に係る酸素を含む
気体の通気流量を調整する制御方法に関しては酸化還元
電位（以下、ＯＲＰと称す）によるものが知られてい
る。すなわち、従来のＯＲＰによる通気流量制御方法は
ＯＲＰと亜硫酸濃度の相関関係を求めた結果から予めＯ
ＲＰ設定値を決定し、吸収液のＯＲＰを連続的に検出し
た信号とＯＲＰ設定値との偏差記号により通気流量を制
御するものであった。As a control method for adjusting the flow rate of the gas containing oxygen related to the oxidation of calcium sulfite, there is known a control method based on a redox potential (hereinafter referred to as ORP). That is, according to the conventional ventilation flow rate control method using ORP, it is possible to calculate the O
The RP set value was determined, and the ventilation flow rate was controlled by the deviation symbol between the signal for continuously detecting the ORP of the absorbing liquid and the ORP set value.
【０００７】しかしながら、排ガス中には過剰空気燃焼
等からもたらされる酸素が含まれており、上記の制御方
法では、酸素を含む気体の通気流量をほぼ０にしてもＯ
ＲＰ値が設定値範囲以下にならない場合が生じるという
問題点があった。However, the exhaust gas contains oxygen derived from excess air combustion and the like, and in the above control method, even if the flow rate of the gas containing oxygen is set to almost 0, O
There is a problem that the RP value may not fall below the set value range.
【０００８】[0008]
【発明が解決しようとする課題】本発明は、従来の上記
問題点を解決するものであって、酸素を含む気体の通気
流量をほぼ０にしてもＯＲＰ値が設定値範囲以下になら
ない場合であっても、吸収液のＯＲＰ値を設定値以下に
することの出来る湿式排煙脱硫方法及びその装置を提供
することを目的とする。DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and in the case where the ORP value does not fall below the set value range even when the flow rate of the gas containing oxygen is almost zero. Even if it exists, it aims at providing the wet flue gas desulfurization method and its apparatus which can make the ORP value of an absorption liquid below a preset value.
【０００９】[0009]
【課題を解決するための手段】本発明は、硫黄酸化物を
含む排ガスとカルシウム化合物を含有する吸収液とを気
液接触させて排ガス中の硫黄酸化物を吸収除去し、生成
した亜硫酸カルシウムを含む吸収液に酸素を含む気体を
供給して石膏を生成する湿式排煙脱硫方法において、前
記吸収液に酸化抑制剤を供給して該吸収液の酸化還元電
位を調整することを特徴とする。According to the present invention, an exhaust gas containing sulfur oxides and an absorbing liquid containing a calcium compound are brought into gas-liquid contact to absorb and remove sulfur oxides in the exhaust gas, thereby producing calcium sulfite. In a wet flue gas desulfurization method of supplying a gas containing oxygen to an absorbing liquid containing oxygen to generate gypsum, an oxidation inhibitor is supplied to the absorbing liquid to adjust the redox potential of the absorbing liquid.
【００１０】また、前記吸収液の酸化還元電位を測定
し、該酸化還元電位に応じて酸素を含む気体の供給量を
調整し、該酸化還元電位が酸素を含む気体の供給量によ
る調整範囲を超えて高くなった場合に、該吸収液に酸化
抑制剤を供給して該酸化還元電位を調整することを特徴
とする。Further, the redox potential of the absorption liquid is measured, the supply amount of the gas containing oxygen is adjusted according to the redox potential, and the adjustment range is adjusted by the supply amount of the gas containing oxygen. When it becomes higher than the above value, an oxidation inhibitor is supplied to the absorption liquid to adjust the redox potential.
【００１１】さらには、前記酸化抑制剤は、シリコン
系、油脂系、脂肪酸系、鉱油系、アルコール系、アミド
系、リン酸エステル系、金属せっけん系の消泡剤、アル
コールおよびグリセリンから選ばれる何れか一つである
こと又は何れか二つ以上の混合物であることを特徴とす
る。Further, the oxidation inhibitor is selected from silicon-based, oil-based, fat-based, fatty acid-based, mineral oil-based, alcohol-based, amide-based, phosphoric acid ester-based, metal soap-based defoaming agents, alcohols and glycerin. It is characterized by being one or a mixture of any two or more.
【００１２】また、本発明は、硫黄酸化物を含む排ガス
とカルシウム化合物を含有する吸収液とを気液接触させ
て排ガス中の硫黄酸化物を吸収除去させる吸収塔と、生
成した亜硫酸カルシウムを含む吸収液に酸素を含む気体
を供給する酸素含有気体供給設備を具備する湿式排煙脱
硫装置において、さらに酸化抑制剤を前記吸収塔内に供
給する酸化抑制剤供給設備を具備することを特徴とす
る。The present invention also includes an absorption tower for absorbing and removing the sulfur oxides in the exhaust gas by bringing the exhaust gas containing the sulfur oxides and the absorption liquid containing the calcium compound into gas-liquid contact, and the produced calcium sulfite. A wet flue gas desulfurization apparatus having an oxygen-containing gas supply facility for supplying a gas containing oxygen to an absorbing liquid, further comprising an oxidation inhibitor supply facility for supplying an oxidation inhibitor into the absorption tower. .
【００１３】[0013]
【発明の実施の形態】以下、本発明の実施の形態を説明
する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
【００１４】図１は本発明に係る湿式排煙脱硫装置の一
実施の形態の例についてその概略構成を示す系統図であ
る。FIG. 1 is a system diagram showing a schematic structure of an embodiment of a wet flue gas desulfurization apparatus according to the present invention.
【００１５】亜硫酸ガスを含む燃焼排ガスＡは、排ガス
ダクト２を通って吸収塔１に導入される。吸収塔１の底
部の吸収液４はポンプ１３により吸収液循環ライン１２
を通ってスプレヘッダー１０へ送られ、スプレヘッダー
１０に具備されたスプレノズルよりスプレーされる。そ
して、スプレーされた吸収液は吸収塔１内に導入された
前記排ガスＡと気液接触し、排ガスＡ中から亜硫酸ガス
を吸収除去しつつ重力により落下し吸収塔１の底部へ戻
る。亜硫酸ガスを除去された排ガスＢは排ガスダクト３
を通って系外へ導かれ、例えばさらに必要な処理をした
あと煙突から大気に放出される。The combustion exhaust gas A containing sulfurous acid gas is introduced into the absorption tower 1 through the exhaust gas duct 2. The absorption liquid 4 at the bottom of the absorption tower 1 is transferred to the absorption liquid circulation line 12 by the pump 13.
It is then sent to the spray header 10 and sprayed from a spray nozzle provided in the spray header 10. Then, the sprayed absorption liquid comes into gas-liquid contact with the exhaust gas A introduced into the absorption tower 1, falls by gravity while absorbing and removing the sulfurous acid gas from the exhaust gas A, and returns to the bottom of the absorption tower 1. The exhaust gas B from which the sulfurous acid gas has been removed is the exhaust gas duct 3
It is led to the outside of the system through, for example, further processed, and then released from the chimney to the atmosphere.
【００１６】一方、本実施の形態の例では酸素を含んだ
気体として空気を使用し、図示しないブロワーによりラ
イン６を通ってバブリングヘッダー５より噴出させ、亜
硫酸ガスを吸収した吸収液４と反応し、石膏が生成す
る。生成した石膏を含む吸収液４は吸収液循環ライン１
２から石膏回収ライン２３へと一部が抜き出され、ベル
トフィルター式濾過装置等によって固液分離され石膏が
回収される。分離された液の一部は補給水として吸収塔
にもどされ、石灰スラリが石灰スラリ供給ライン１５よ
り吸収塔１内に供給され吸収液４と混合されることによ
り吸収液の亜硫酸ガス吸収性能が維持される。また、残
りの液は排水として系外に排出される。On the other hand, in the example of the present embodiment, air is used as the gas containing oxygen, and is blown out from the bubbling header 5 through the line 6 by a blower (not shown) to react with the absorbing liquid 4 which has absorbed the sulfurous acid gas. , Gypsum is produced. The absorption liquid 4 containing the generated gypsum is the absorption liquid circulation line 1
A part of the gypsum is extracted from 2 to the gypsum recovery line 23 and solid-liquid separated by a belt filter type filtration device or the like to recover gypsum. A part of the separated liquid is returned to the absorption tower as make-up water, and the lime slurry is supplied into the absorption tower 1 through the lime slurry supply line 15 and mixed with the absorption liquid 4, whereby the sulfur dioxide absorption performance of the absorption liquid is improved. Maintained. Further, the remaining liquid is discharged outside the system as waste water.
【００１７】酸化抑制剤溶液は酸化抑制剤溶液タンク１
６からバルブ１９が具備された酸化抑制剤溶液供給ライ
ン１７から吸収塔１の底部の吸収液４に供給されるよう
になっている。The oxidation inhibitor solution is an oxidation inhibitor solution tank 1
6 to the oxidation inhibitor solution supply line 17 provided with a valve 19 to supply the absorption liquid 4 at the bottom of the absorption tower 1.
【００１８】吸収液循環ライン１２には酸化還元電位計
（０ＲＰ計）２０が具備され循環吸収液の酸化還元電位
（０ＲＰ）を計測し、その計測信号は第１制御器２１及
び第２制御器２にそれぞれ送信される。An oxidation-reduction potential meter (0RP meter) 20 is provided in the absorption liquid circulation line 12 to measure the oxidation-reduction potential (0RP) of the circulation absorption liquid, and the measurement signal is the first controller 21 and the second controller. 2 respectively.
【００１９】第１制御器２１は前記０ＲＰ計２０からの
入力信号と酸化還元設定値（ＯＰＲ設定値）とを比較演
算し、出力信号によりバルブ８の弁開度を制御してバブ
リングヘッダー５より噴出する空気量を調整できるよう
になっている。The first controller 21 compares the input signal from the 0RP meter 20 with the redox set value (OPR set value) and controls the valve opening of the valve 8 by the output signal to output from the bubbling header 5. The amount of air blown out can be adjusted.
【００２０】第２制御器２２は前記０ＲＰ計２０からの
入力信号と酸化還元設定値（ＯＰＲ設定値）とを比較演
算し、出力信号によりバルブ１９の弁開度を制御して吸
収塔への酸化抑制剤の供給量を調整できるようになって
いる。The second controller 22 compares the input signal from the 0RP meter 20 with the redox set value (OPR set value), and controls the valve opening of the valve 19 by the output signal to send to the absorption tower. The supply amount of the oxidation inhibitor can be adjusted.
【００２１】次に、上記循環吸収液のＯＲＰを指標とし
た空気の通気流量の制御と酸化抑制剤の添加タイミング
を、図２を参照して説明する。Next, the control of the air flow rate of the air and the addition timing of the oxidation inhibitor using the ORP of the circulating absorbent as an index will be described with reference to FIG.
【００２２】（第１ステージ）実効的な亜硫酸ガス量の
高い排ガスを前記導入管２から前記吸収塔１に導入し、
循環ポンプ１３を作動して前記吸収塔１底部の吸収液４
を、吸収液循環ライン１２を通して前記吸収塔１のスプ
レヘッダー１０から噴射し、前記排ガスと気液接触させ
てその排ガス中の亜硫酸ガスを亜硫酸イオンとして吸収
し脱硫を行う。このとき、前記吸収液循環ライン１２内
を流通する吸収液のＯＲＰ値をＯＲＰ計２０で検出し、
その検出信号を第１制御器２１に出力する。この第１制
御器２１では、前記ＯＲＰ計２０から入力されるＯＲＰ
の検出信号とＯＲＰ設定値とを比較する。この比較結果
において、ＯＲＰ設定値を超える検出信号が入力された
ときには前記第１制御器２１から前記第１ＰＩＤ調節計
７に前記第１バルブ８の開度を下げる信号を出力する。
これにより、図示しない空気供給ブロアの作動により空
気導入用流路６およびバブリングヘッダー５から吸収塔
１底部の吸収液に通気される空気流量が低減され、これ
に伴ってＯＲＰ値が低下してＯＲＰ設定値に合致する。
一方、この比較結果において、ＯＲＰ設定値未満の検出
信号が入力されたときには前記第１制御器２１から前記
第１ＰＩＤ調節計７に前記第１バルブ８の開度を上げる
信号を出力する。これにより、図示しない空気供給ブロ
アの作動により空気導入用流路６およびバブリングヘッ
ダー５から吸収塔１底部の吸収液に通気される空気流量
が増大され、これに伴ってＯＲＰ値が増大してＯＲＰ設
定値に合致する。(First Stage) Exhaust gas having a high effective amount of sulfurous acid gas is introduced into the absorption tower 1 through the introduction pipe 2,
By operating the circulation pump 13, the absorption liquid 4 at the bottom of the absorption tower 1
Is sprayed from the spray header 10 of the absorption tower 1 through the absorption liquid circulation line 12 and is brought into gas-liquid contact with the exhaust gas to absorb the sulfurous acid gas in the exhaust gas as sulfite ion for desulfurization. At this time, the ORP value of the absorbing liquid flowing through the absorbing liquid circulation line 12 is detected by the ORP meter 20,
The detection signal is output to the first controller 21. In the first controller 21, the ORP input from the ORP meter 20 is input.
And the ORP set value are compared. As a result of this comparison, when a detection signal exceeding the ORP set value is input, the first controller 21 outputs a signal for decreasing the opening degree of the first valve 8 to the first PID controller 7.
As a result, the flow rate of air that is aerated from the air introduction flow path 6 and the bubbling header 5 to the absorbent at the bottom of the absorption tower 1 is reduced by the operation of the air supply blower (not shown), and the ORP value is reduced accordingly. Match the set value.
On the other hand, in the comparison result, when a detection signal less than the ORP set value is input, the first controller 21 outputs a signal for increasing the opening degree of the first valve 8 to the first PID controller 7. As a result, the flow rate of air that is aerated from the air introduction flow path 6 and the bubbling header 5 to the absorbent at the bottom of the absorption tower 1 is increased by the operation of the air supply blower (not shown), and the ORP value is increased accordingly. Match the set value.
【００２３】このような第１ステージにおいてＯＲＰを
連続的に検出しつつ、そのＯＲＰ値に基づいて例えば第
１制御器２１および第１ＰＩＤ調節計７により第１バル
ブ８の開度を調節して吸収液４中への空気の通気流量を
制御することにより、図２に示すように吸収液のＯＲＰ
値をＯＲＰ設定値に収めることが可能なり、吸収液４中
の亜硫酸イオンを適切な濃度に制御できるとともに、Ｓ
2Ｏ6，Ｓ2Ｏ8のような過酸化物の生成を防止してＣＯＤ
の発生を低減することができる。While continuously detecting the ORP in the first stage as described above, the opening degree of the first valve 8 is adjusted and absorbed by the first controller 21 and the first PID controller 7 based on the ORP value, for example. By controlling the aeration flow rate of air into the liquid 4, as shown in FIG.
The value can be set within the ORP set value, the sulfite ion in the absorbent 4 can be controlled to an appropriate concentration, and S
COD by preventing the formation of peroxides such as 2 O 6 and S 2 O 8
Can be reduced.
【００２４】（第２ステージ）実効的な亜硫酸ガス量の
低い排ガス（例えば流量が第１ステージの排ガス流量の
半分の排ガス）を前記導入管２から前記吸収塔１に導入
し、循環ポンプ１３を作動して前記吸収塔１底部の吸収
液４を吸収液循環ライン１２を通して前記吸収塔１のス
プレヘッダー１０から噴射し、前記排ガスと気液接触さ
せてその排ガス中の亜硫酸ガスを亜硫酸イオンとして吸
収し脱硫を行う。このとき、前記吸収液循環ライン１２
内を流通する吸収液のＯＲＰ値をＯＲＰ計２０で検出す
ると、前記吸収塔１の吸収液で吸収される亜硫酸イオン
濃度に対してバブリングヘッダー５から通気される空気
流量が過剰になるため、図２のステージ２に示すように
そのＯＲＰ検出量はＯＲＰ設定値を超える値になる。こ
のような検出信号を前記第１制御器２１に出力すると、
この第１制御器２１から前記第１ＰＩＤ調節計７に前記
第１バルブ８の開度を下げる信号を出力する。これによ
り、図示しない空気供給ブロアの作動により空気導入用
流路６およびバブリングヘッダー５から吸収塔１底部の
吸収液に通気される空気流量が低減される。(Second Stage) Exhaust gas having a low effective sulfurous acid gas amount (for example, exhaust gas whose flow rate is half of the exhaust gas flow rate of the first stage) is introduced from the introduction pipe 2 into the absorption tower 1, and the circulation pump 13 is operated. When operating, the absorption liquid 4 at the bottom of the absorption tower 1 is jetted from the spray header 10 of the absorption tower 1 through the absorption liquid circulation line 12 and brought into gas-liquid contact with the exhaust gas to absorb the sulfurous acid gas in the exhaust gas as sulfite ions. Then desulfurize. At this time, the absorption liquid circulation line 12
When the ORP value of the absorbing liquid flowing through the inside is detected by the ORP meter 20, the flow rate of the air aerated from the bubbling header 5 becomes excessive with respect to the sulfite ion concentration absorbed by the absorbing liquid of the absorption tower 1. As shown in stage 2 of 2, the ORP detection amount becomes a value exceeding the ORP set value. When such a detection signal is output to the first controller 21,
This first controller 21 outputs a signal for decreasing the opening of the first valve 8 to the first PID controller 7. As a result, the flow rate of air aerated from the air introduction flow path 6 and the bubbling header 5 to the absorbent at the bottom of the absorption tower 1 by the operation of the air supply blower (not shown) is reduced.
【００２５】しかしながら、前記第１バルブ８の絞り操
作により吸収液に通気される空気流量を低減して、通気
される空気流量を最小に制御しても、排気ガスの実効的
な亜硫酸ガス量が少ないためにＯＲＰ計２０で検出され
るＯＲＰ値がＯＲＰ設定値を超える場合がある。このと
き（図２のＰ１点）、前記ＯＲＰ計２０から出力される
ＯＲＰの検出信号と空気導入用流路６に介装された流量
検出計９から出力された空気流量の検出信号とが入力さ
れた第２制御器２２において、前記ＯＲＰ計２０からＯ
ＲＰ設定値を超えるＯＲＰ検出信号が入力され、かつ前
記流量検出計９から空気流量の最小値以下の空気流量検
出信号が入力されるため、この第２制御器２２から第２
ＰＩＤ調節計１８に流路１７に介装された第２バルブ１
９を一定時間開動作させる信号を出力する。この第２バ
ルブ１９の一定時間の開動作により酸化抑制剤溶液収容
タンク１６内の酸化抑制剤溶液が流路１７を通して前記
吸収塔１の吸収液４に一定量供給される。これによっ
て、図２に示すように吸収液４のＯＲＰ値が下がってＯ
ＲＰ設定値に合致される。However, even if the flow rate of the air aerated to the absorbing liquid is reduced by controlling the first valve 8 and the flow rate of the aerated air is controlled to the minimum, the effective amount of sulfurous acid gas in the exhaust gas is reduced. Because of the small amount, the ORP value detected by the ORP meter 20 may exceed the ORP set value. At this time (point P1 in FIG. 2), the ORP detection signal output from the ORP meter 20 and the air flow rate detection signal output from the flow rate detector 9 interposed in the air introduction flow path 6 are input. In the second controller 22 that has been
Since the ORP detection signal that exceeds the RP set value is input and the air flow rate detection signal that is less than or equal to the minimum air flow rate is input from the flow rate detector 9, the second controller 22
The second valve 1 installed in the flow path 17 in the PID controller 18
A signal for opening 9 for a predetermined time is output. By the opening operation of the second valve 19 for a certain period of time, a certain amount of the oxidation inhibitor solution in the oxidation inhibitor solution storage tank 16 is supplied to the absorption liquid 4 of the absorption tower 1 through the flow path 17. As a result, the ORP value of the absorbing liquid 4 decreases as shown in FIG.
It matches the RP setting.
【００２６】前記酸化抑制剤溶液の添加により吸収液４
のＯＲＰ値がＯＲＰ設定値未満になる図２のＰ２点にお
いて、前記第１制御器２１から前記第１ＰＩＤ調節計７
に前記第１バルブ８の開度を上げる信号が出力される。
これにより、図示しない空気供給ブロアの作動により空
気導入用流路６およびバブリングヘッダー５から吸収塔
１底部の吸収液に通気される空気流量が増大され、これ
に伴ってＯＲＰ値が増大してＯＲＰ設定値に合致する。The absorption liquid 4 is obtained by adding the oxidation inhibitor solution.
2 becomes less than the ORP set value, the first PID controller 7 from the first controller 21 at the point P2 in FIG.
A signal for increasing the opening of the first valve 8 is output to.
As a result, the flow rate of air that is aerated from the air introduction flow path 6 and the bubbling header 5 to the absorbent at the bottom of the absorption tower 1 is increased by the operation of the air supply blower (not shown), and the ORP value is increased accordingly. Match the set value.
【００２７】このような第２ステージにおいて、ＯＲＰ
を連続的に検出しつつ、その検出値に基づいて例えば第
１制御器２１および第１ＰＩＤ調節計７により第１バル
ブ８の開度を制御して吸収液４に通気する空気流量を最
小値にしても、図２に示すように吸収液のＯＲＰ値がＯ
ＲＰ設定値を超えるときには、ＯＲＰの検出値および通
気する空気流量の検出値に基づいて例えば第２制御器２
２および第２ＰＩＤ調節計１８により第２バルブ１９を
一定時間開いて酸化抑制剤を吸収液に一定量添加するこ
とによって、吸収液のＯＲＰ値をＯＲＰ設定値に収める
ことが可能なるため、Ｓ2Ｏ6，Ｓ2Ｏ8のような過酸化物
の生成を防止してＣＯＤの発生を低減することができ
る。In such a second stage, the ORP
Is continuously detected, the opening of the first valve 8 is controlled by, for example, the first controller 21 and the first PID controller 7 based on the detected value to minimize the flow rate of air vented to the absorbent 4. However, as shown in FIG. 2, the ORP value of the absorbing liquid is O.
When it exceeds the RP set value, for example, the second controller 2
Because by adding a certain amount of the second valve 19 to absorb liquid oxidation inhibitors open a predetermined time by the second and 2PID adjusting meter 18, Naru can keep the ORP value of the absorbing liquid in ORP setting value, S 2 Generation of COD can be reduced by preventing the generation of peroxides such as O 6 and S 2 O 8 .
【００２８】以上、本発明の実施形態によれば排ガス中
の亜硫酸ガス量が実効的に低下し、通気する空気流量を
最小に制御しても吸収液のＯＲＰの検出値がＯＲＰ設定
値を超えた時に、前記吸収液中に酸化抑制剤を投入して
吸収液のＯＲＰの検出値をＯＲＰ設定値以下に低減させ
ることによって、Ｓ2Ｏ6，Ｓ2Ｏ8のような過酸化物の生
成を抑制ないし防ぐことができる。その結果、排煙脱硫
処理の系内の吸収液の一部を排出するときに、ＣＯＤの
原因となる前記過酸化物量を低減した排水を排出するこ
とができるため、廃水処理の負荷を軽減することができ
る。As described above, according to the embodiment of the present invention, the amount of sulfurous acid gas in the exhaust gas is effectively reduced, and the ORP detection value of the absorbing liquid exceeds the ORP set value even if the flow rate of the air to be aerated is controlled to the minimum. At this time, by adding an oxidation inhibitor to the absorption liquid to reduce the ORP detection value of the absorption liquid to the ORP set value or less, the formation of peroxides such as S 2 O 6 and S 2 O 8 is generated. Can be suppressed or prevented. As a result, when a part of the absorption liquid in the system for flue gas desulfurization treatment is discharged, it is possible to discharge the wastewater in which the amount of the peroxide that causes COD is reduced, so that the load of wastewater treatment is reduced. be able to.
【００２９】なお、前述した実施形態では炭酸カルシウ
ムを含む吸収液を用いたが、炭酸カルシウム以外のアル
カリ系化合物を含む水溶液を用いてもよい。Although the absorbing solution containing calcium carbonate is used in the above-described embodiment, an aqueous solution containing an alkaline compound other than calcium carbonate may be used.
【００３０】[0030]
【実施例】以下、本発明の好ましい実施例を前述した図
１を参照して説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIG.
【００３１】（実施例１）
（１）適正な亜硫酸ガス量を有する排ガスの脱硫
まず、亜硫酸ガス（ＳＯ2）を３５０ｐｐｍ含む排ガス
を図１の矢印Ａに示すように導入管２を通して吸収塔１
の底部付近に５００，０００Ｎｍ3／ｈの流量で導入し
た。導入された排ガスは、前記吸収塔１内を上昇した。
循環ポンプ１３を作動して前記吸収塔１底部の石灰が１
５重量％の濃度で溶解された吸収液４を、吸収液循環ラ
イン１２を通して前記吸収塔１のスプレヘッダー１０か
ら噴射し、排ガスと気液接触させてその排ガス中の亜硫
酸ガスを亜硫酸イオンとして吸収し脱硫を行った。脱硫
後の排ガスは、デミスタ１１を通過し、ここで排ガス中
のミストおよび煤塵を捕集し、処理された排ガスを図１
の矢印Ｂに示すように吸収塔１頂部の排出管３を通して
系外に排気した。(Example 1) (1) Desulfurization of exhaust gas having an appropriate amount of sulfurous acid gas First, exhaust gas containing 350 ppm of sulfurous acid gas (SO 2 ) is passed through an inlet pipe 2 as shown by an arrow A in FIG.
Was introduced at a flow rate of 500,000 Nm 3 / h near the bottom of the. The introduced exhaust gas went up in the absorption tower 1.
By operating the circulation pump 13, the lime at the bottom of the absorption tower 1
The absorption liquid 4 dissolved at a concentration of 5% by weight is injected from the spray header 10 of the absorption tower 1 through the absorption liquid circulation line 12 and brought into gas-liquid contact with the exhaust gas to absorb the sulfurous acid gas in the exhaust gas as sulfite ion. Then, desulfurization was performed. The exhaust gas after desulfurization passes through the demister 11, where mist and soot in the exhaust gas are collected, and the processed exhaust gas is shown in FIG.
As indicated by the arrow B in FIG. 1, the gas was exhausted to the outside of the system through the discharge pipe 3 at the top of the absorption tower 1.
【００３２】前述した脱硫工程において、前記吸収液循
環ライン１２内を流通する吸収液のＯＲＰ値をＯＲＰ計
２０で検出し、その検出信号を第１制御器２１に出力し
た。この第１制御器２１では、前記ＯＲＰ計２０から入
力されるＯＲＰの検出信号とＯＲＰ設定値とが比較され
る。この比較結果において、ＯＲＰ設定値（例えば１０
０ｍＶ）を超える検出信号が入力されたときには前記第
１制御器２１から前記第１ＰＩＤ調節計７に前記第１バ
ルブ８の開度を下げる信号を出力した。これにより、図
示しない空気供給ブロアの作動により空気導入用流路６
およびバブリングヘッダー５から吸収塔１底部の吸収液
に通気される空気流量が低減され、これに伴ってＯＲＰ
値が低下してＯＲＰ設定値に合致した。一方、この比較
結果において、ＯＲＰ設定値未満の検出信号が入力され
たときには前記第１制御器２１から前記第１ＰＩＤ調節
計７に前記第１バルブ８の開度を上げる信号を出力し
た。これにより、図示しない空気供給ブロアの作動によ
り空気導入用流路６およびバブリングヘッダー５から吸
収塔１底部の吸収液に通気される空気流量が増大され、
これに伴ってＯＲＰ値が増大してＯＲＰ設定値に合致し
た。In the desulfurization step described above, the ORP value of the absorption liquid flowing through the absorption liquid circulation line 12 was detected by the ORP meter 20, and the detection signal was output to the first controller 21. In the first controller 21, the ORP detection signal input from the ORP meter 20 is compared with the ORP set value. In this comparison result, the ORP set value (for example, 10
When a detection signal exceeding 0 mV) is input, the first controller 21 outputs a signal to decrease the opening degree of the first valve 8 to the first PID controller 7. As a result, the air introduction flow path 6 is activated by the operation of the air supply blower (not shown).
Also, the flow rate of air aerated from the bubbling header 5 to the absorption liquid at the bottom of the absorption tower 1 is reduced, and the ORP is accordingly reduced.
The value decreased to match the ORP setting value. On the other hand, in the comparison result, when the detection signal less than the ORP set value is input, the first controller 21 outputs a signal for increasing the opening degree of the first valve 8 to the first PID controller 7. As a result, the flow rate of air aerated from the air introduction flow path 6 and the bubbling header 5 to the absorbent at the bottom of the absorption tower 1 by the operation of the air supply blower (not shown) is increased,
Along with this, the ORP value increased and matched the ORP set value.
【００３３】このように前記第１制御器２１および第１
ＰＩＤ調節計７により第１バルブ８の開度を調節して吸
収液４中への空気の通気流量を制御することにより、吸
収液のＯＲＰ値をＯＲＰ設定値に合致させることが可能
となり、吸収液４中の亜硫酸イオンを適切な濃度に制御
された。As described above, the first controller 21 and the first controller 21
By adjusting the opening of the first valve 8 by the PID controller 7 to control the air flow rate into the absorbent 4, it is possible to make the ORP value of the absorbent match the ORP set value. The sulfite ion in the liquid 4 was controlled to an appropriate concentration.
【００３４】（２）亜硫酸ガス量が実効的に低い排ガス
の脱硫
前記濃度の亜硫酸ガス（ＳＯ2）を含む排ガスを図１の
矢印Ａに示すように導入管２を通して吸収塔１の底部付
近に前記流量の半分の流量（２５０，０００Ｎｍ3／
ｈ）で導入し、同様な脱硫、排ガス中のミストおよび煤
塵を捕集し、処理された排ガスを図１の矢印Ｂに示すよ
うに吸収塔１頂部の排出管３を通して系外に排気した。(2) Desulfurization of Exhaust Gas with Effectively Low Sulfurous Acid Gas Exhaust gas containing sulfur dioxide (SO 2 ) with the above concentration is introduced into the vicinity of the bottom of the absorption tower 1 through the inlet pipe 2 as shown by arrow A in FIG. Half the flow rate (250,000 Nm 3 /
In the same manner as in h), the same desulfurization, mist and soot in the exhaust gas were collected, and the treated exhaust gas was exhausted to the outside of the system through the exhaust pipe 3 at the top of the absorption tower 1 as shown by an arrow B in FIG.
【００３５】前記脱硫において、前記循環流路１２内を
流通する吸収液をＯＲＰ計２０でＯＲＰを測定すると、
そのＯＲＰ値がＯＲＰ設定値である１００ｍＶから２０
０ｍＶに増加した。このため、このＯＲＰ検出信号を第
１制御器２１に出力し、この第１制御器２１から第１Ｐ
ＩＤ調節計７に第１バルブ８の開度を下げる信号を出力
した。これにより、図示しない空気供給ブロアの作動に
より空気導入用流路６およびバブリングヘッダー５から
吸収塔１底部の吸収液に通気される空気流量が低減され
た。In the desulfurization, when the ORP meter 20 measures the ORP of the absorbing liquid flowing in the circulation passage 12,
The ORP value is 20 from 100 mV which is the ORP setting value.
It increased to 0 mV. Therefore, this ORP detection signal is output to the first controller 21, and the first controller 21 outputs the first P
A signal for lowering the opening of the first valve 8 was output to the ID controller 7. As a result, the flow rate of air aerated from the air introduction flow path 6 and the bubbling header 5 to the absorbent at the bottom of the absorption tower 1 by the operation of the air supply blower (not shown) was reduced.
【００３６】しかしながら、前記第１バルブ８の絞り操
作により吸収液に通気される空気流量を低減し、通気す
る空気流量を最小に制御しても排気ガスの実効的な亜硫
酸ガス量が少ないためにＯＲＰ計２０で検出されるＯＲ
Ｐ値がＯＲＰ設定値を超えた。このとき、第２制御器２
２において前記ＯＲＰ計２０からＯＲＰ設定値を超える
ＯＲＰ検出信号が入力され、かつ空気導入用流路６に介
装された前記流量検出計９から空気流量の最小値以下の
空気流量検出信号が入力されたため、この第２制御器２
２から第２ＰＩＤ調節計１８に流路１７に介装された第
２バルブ１９を一定時間開動作させる信号を出力した。
第２バルブ１９の一時間の開動作により、酸化抑制剤溶
液収容タンク１６内の酸化抑制剤溶液（例えばシリコン
樹脂系食品添加用消泡剤の１００重量％濃度の溶液）を
流路１７を通して前記吸収塔１の吸収液４に供給した。
このとき、前記消泡剤の前記吸収液に供給する量は通気
した空気量２１０ｍ3あたり４００ｍＬ（０．５ｐｐ
ｍ）とした。これによって、吸収液４のＯＲＰ値がＯＲ
Ｐ設定値（１００ｍＶ）未満に低減された。However, the effective amount of sulfurous acid gas in the exhaust gas is small even if the flow rate of the air ventilated in the absorbing liquid is reduced by controlling the first valve 8 to control the ventilated air flow rate to the minimum. OR detected by ORP meter 20
P value exceeded the ORP setting value. At this time, the second controller 2
2, an ORP detection signal exceeding the ORP set value is input from the ORP meter 20, and an air flow rate detection signal equal to or less than the minimum value of the air flow rate is input from the flow rate detector 9 interposed in the air introduction flow path 6. As a result, this second controller 2
From No. 2, a signal for opening the second valve 19 interposed in the flow path 17 for a certain period of time was output to the second PID controller 18.
When the second valve 19 is opened for one hour, the oxidation inhibitor solution (for example, a solution of the silicone resin-based food additive defoaming agent having a concentration of 100% by weight) in the oxidation inhibitor solution storage tank 16 is passed through the flow path 17 to be described above. It was supplied to the absorption liquid 4 of the absorption tower 1.
At this time, the amount of the defoaming agent to be supplied to the absorbing liquid is 400 mL (0.5 pp) per 210 m 3 of aerated air.
m). As a result, the ORP value of the absorbing liquid 4 becomes OR.
It was reduced to less than the P set value (100 mV).
【００３７】前記酸化抑制剤溶液の添加により吸収液４
のＯＲＰ値がＯＲＰ設定値未満になると、前記第１制御
器２１から前記第１ＰＩＤ調節計７に前記第１バルブ８
の開度を上げる信号が出力された。これにより、図示し
ない空気供給ブロアの作動により空気導入用流路６およ
びバブリングヘッダー５から吸収塔１底部の吸収液に通
気される空気流量が増大され、これに伴ってＯＲＰ値が
増大してＯＲＰ設定値に合致した。The absorption liquid 4 is obtained by adding the above-mentioned oxidation inhibitor solution.
Is less than the ORP set value, the first controller 21 causes the first PID controller 7 to operate the first valve 8
A signal to increase the opening of was output. As a result, the flow rate of air that is aerated from the air introduction flow path 6 and the bubbling header 5 to the absorbent at the bottom of the absorption tower 1 is increased by the operation of the air supply blower (not shown), and the ORP value is increased accordingly. It matches the set value.
【００３８】（比較例１）
（１）適正な亜硫酸ガス量を有する排ガスの脱硫
実施例１と同様な手法により適正な亜硫酸ガス濃度を有
する排ガスの脱硫を行った。Comparative Example 1 (1) Desulfurization of Exhaust Gas Having Proper Sulfurous Acid Gas Desulfurization of exhaust gas having an appropriate sulfurous acid gas concentration was carried out in the same manner as in Example 1.
【００３９】（２）亜硫酸ガス量が実効的に低い排ガス
の脱硫
実施例１と同様な濃度の亜硫酸ガス（ＳＯ2）を含む排
ガスを図１の矢印Ａに示すように導入管２を通して吸収
塔１の底部付近に２５０，０００Ｎｍ3／ｈの流量で導
入し、実施例１と同様な脱硫、排ガス中のミストおよび
煤塵を捕集し、処理された排ガスを図１の矢印Ｂに示す
ように吸収塔１頂部の排出管３を通して系外に排気し
た。この脱硫において、実施例１と同様に第１制御器２
１により第１ＰＩＤ調節計７に第１バルブ８の開度を下
げ、図示しない空気供給ブロアの作動により空気導入用
流路６およびバブリングヘッダー５から吸収塔１底部の
吸収液に通気される空気流量を低減させる操作のみを行
い、酸化抑制剤溶液収容タンク１６内の酸化抑制剤溶液
を流路１７を通して吸収塔１の吸収液４に供給する操作
を行わなかった。(2) Desulfurization of Exhaust Gas with Effectively Low Sulfurous Acid Gas Exhaust gas containing sulfurous acid gas (SO 2 ) with the same concentration as in Example 1 is passed through an inlet pipe 2 as shown by an arrow A in FIG. 1 was introduced at a flow rate of 250,000 Nm 3 / h in the vicinity of the bottom thereof, desulfurization similar to that in Example 1, mist and soot in the exhaust gas were collected, and the treated exhaust gas was supplied as shown by an arrow B in FIG. It was exhausted to the outside of the system through a discharge pipe 3 at the top of the absorption tower 1. In this desulfurization, the first controller 2 is used as in the first embodiment.
1, the opening of the first valve 8 is lowered to the first PID controller 7, and the flow rate of air aerated from the air introduction flow path 6 and the bubbling header 5 to the absorption liquid at the bottom of the absorption tower 1 by the operation of an air supply blower (not shown). Was performed, and the operation of supplying the oxidation inhibitor solution in the oxidation inhibitor solution storage tank 16 to the absorption liquid 4 of the absorption tower 1 through the flow path 17 was not performed.
【００４０】実施例１および比較例１の（１），（２）
の脱硫において、吸収塔頂部の排出管３を通して系外に
排気された処理ガス中の亜硫酸ガス濃度と、吸収液循環
ライン１２から流路２３を通して排出された排水中のＣ
ＯＤ濃度とを測定した。その結果を下記表１に示す。(1) and (2) of Example 1 and Comparative Example 1
In the desulfurization of sulfur, the concentration of sulfurous acid gas in the processing gas exhausted to the outside of the system through the discharge pipe 3 at the top of the absorption tower and the C in the wastewater discharged from the absorption liquid circulation line 12 through the flow path 23.
The OD concentration was measured. The results are shown in Table 1 below.
【００４１】[0041]
【表１】 [Table 1]
【００４２】前記表１から明らかなように実施例１で
は、（２）の亜硫酸ガス量が実効的に低い排ガスの脱硫
処理において、排水中のＣＯＤ量を（１）の適正な亜硫
酸ガス量を有する排ガスの脱硫時とほぼ同程度に低減す
ることができることがわかる。As is clear from Table 1, in Example 1, in the desulfurization treatment of the exhaust gas of (2) in which the amount of sulfurous acid gas is effectively low, the amount of COD in the waste water is adjusted to the appropriate amount of sulfurous acid gas in (1). It can be seen that the exhaust gas can be reduced to almost the same level as during desulfurization.
【００４３】これに対し、比較例１では（２）の亜硫酸
ガス量が実効的に低い排ガスの脱硫処理において、排水
中のＣＯＤ量が（１）の適正な亜硫酸ガス量を有する排
ガスの脱硫時に比べて増大することがわかる。これは、
前記（２）の脱硫工程で吸収液に通気する空気流量を最
小に制御しても、その吸収液のＯＲＰ値がＯＲＰ設定値
を超えて吸収液に生成された亜硫酸イオンが過度に酸化
されてＳ2Ｏ6，Ｓ2Ｏ8のような過酸化物を生成するため
である。On the other hand, in Comparative Example 1, in the desulfurization treatment of the exhaust gas of (2) where the sulfur dioxide gas amount is effectively low, the desulfurization of the exhaust gas having the proper sulfur dioxide gas amount of the COD amount of (1) is performed. It turns out that it increases compared with. this is,
Even if the flow rate of the air ventilated through the absorbing solution is controlled to the minimum in the desulfurization step (2), the ORP value of the absorbing solution exceeds the ORP set value, and the sulfite ion generated in the absorbing solution is excessively oxidized. This is for producing peroxides such as S 2 O 6 and S 2 O 8 .
【００４４】[0044]
【発明の効果】以上詳述したように、本発明によれば排
ガス中の亜硫酸ガス量が実効的に低下して、通気する酸
素含有ガス流量を最小にしてもＯＲＰ値を設定値以下に
制御できなくなった場合でも、ＣＯＤの発生原因である
Ｓ2Ｏ6，Ｓ2Ｏ8のような過酸化物の生成を防ぐことがで
き、ひいてはＣＯＤの原因となる前記過酸化物量を低減
して廃水処理の負荷を軽減できる等顕著な効果を奏する
排煙脱硫方法を提供することができる。As described in detail above, according to the present invention, the amount of sulfurous acid gas in the exhaust gas is effectively reduced, and the ORP value is controlled to be equal to or less than the set value even when the flow rate of the oxygen-containing gas to be aerated is minimized. Even if it becomes impossible, it is possible to prevent the generation of peroxides such as S 2 O 6 and S 2 O 8 that cause COD, and reduce the amount of the peroxide that causes COD to reduce wastewater. It is possible to provide a flue gas desulfurization method that exhibits remarkable effects such as reduction of the processing load.
【図１】本発明の排煙脱硫方法を実施するための排煙脱
硫装置を示す概略図。FIG. 1 is a schematic diagram showing a flue gas desulfurization apparatus for carrying out a flue gas desulfurization method of the present invention.
【図２】本発明の実施形態における実効的な亜硫酸ガス
量の異なる排ガスの排煙脱硫処理時でのＯＲＰ値の変
化、制御される空気の通気流量および酸化抑制剤の添加
時期を示すグラフ。FIG. 2 is a graph showing changes in the ORP value during flue gas desulfurization treatment of exhaust gases having different effective amounts of sulfurous acid gas, controlled air flow rates, and addition timings of oxidation inhibitors according to an embodiment of the present invention.
１…吸収塔、 ２…導入管、 ３…排出管、 ４…吸収液、 ５…バブリングヘッダー、 ７，１８…ＰＩＤ調節計、 ８，１９…バルブ、 １２…吸収液循環ライン、 １６…酸化抑制剤溶液収容タンク、 ２０…ＯＲＰ計、 ２１．２２…制御器。 1 ... absorption tower, 2 ... Introductory pipe, 3 ... Discharge pipe, 4 ... Absorption liquid, 5 ... Bubbling header, 7,18 ... PID controller 8, 19 ... Valve, 12 ... Absorption liquid circulation line, 16 ... Oxidation inhibitor solution storage tank, 20 ... ORP meter, 21.22 ... Controller.
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 4D002 AA02 AC01 BA02 BA16 CA01 DA05 DA70 EA12 FA03 GA02 GA03 GB05 GB20 4D020 AA06 BA02 CB25 DA01 DA02 DB20 ─────────────────────────────────────────────────── ─── Continued front page F-term (reference) 4D002 AA02 AC01 BA02 BA16 CA01 DA05 DA70 EA12 FA03 GA02 GA03 GB05 GB20 4D020 AA06 BA02 CB25 DA01 DA02 DB20
Claims (4)
合物を含有する吸収液とを気液接触させて排ガス中の硫
黄酸化物を吸収除去し、生成した亜硫酸カルシウムを含
む吸収液に酸素を含む気体を供給して石膏を生成する湿
式排煙脱硫方法において、前記吸収液に酸化抑制剤を供
給して該吸収液の酸化還元電位を調整することを特徴と
する湿式排煙脱硫方法。1. A gas containing oxygen in the absorption liquid containing calcium sulfite produced by absorbing and removing the sulfur oxides in the exhaust gas by gas-liquid contacting the exhaust gas containing sulfur oxides with an absorption liquid containing a calcium compound. In the wet flue gas desulfurization method of supplying gypsum to supply gypsum, an oxidation inhibitor is supplied to the absorption liquid to adjust the redox potential of the absorption liquid.
酸化還元電位に応じて酸素を含む気体の供給量を調整
し、該酸化還元電位が酸素を含む気体の供給量による調
整範囲を超えて高くなった場合に、該吸収液に酸化抑制
剤を供給して該酸化還元電位を調整することを特徴とす
る請求項１記載の湿式排煙脱硫方法。2. The redox potential of the absorption liquid is measured, the supply amount of a gas containing oxygen is adjusted according to the redox potential, and the adjustment range is adjusted by the supply amount of a gas containing oxygen. The wet flue gas desulfurization method according to claim 1, wherein an oxidation inhibitor is supplied to the absorption liquid to adjust the oxidation-reduction potential when the temperature becomes higher than the above.
系、脂肪酸系、鉱油系、アルコール系、アミド系、リン
酸エステル系、金属せっけん系の消泡剤、アルコールお
よびグリセリンから選ばれる何れか一つであること又は
何れか二つ以上の混合物であることを特徴とする請求項
１又は２記載の湿式排煙脱硫方法。3. The oxidation inhibitor is any one selected from silicon-based, oil-based, fatty acid-based, mineral oil-based, alcohol-based, amide-based, phosphoric ester-based, metal soap-based defoaming agents, alcohols and glycerin. The wet flue gas desulfurization method according to claim 1 or 2, wherein the method is one or a mixture of any two or more.
合物を含有する吸収液とを気液接触させて排ガス中の硫
黄酸化物を吸収除去させる吸収塔と、生成した亜硫酸カ
ルシウムを含む吸収液に酸素を含む気体を供給する酸素
含有気体供給設備を具備する湿式排煙脱硫装置におい
て、 さらに酸化抑制剤を前記吸収塔内に供給する酸化抑制剤
供給設備を具備することを特徴とする湿式排煙脱硫装
置。4. An absorption tower for absorbing and removing the sulfur oxides in the exhaust gas by bringing the exhaust gas containing sulfur oxides and the absorption liquid containing a calcium compound into gas-liquid contact, and oxygen in the absorption liquid containing calcium sulfite thus produced. Wet flue gas desulfurization equipment comprising an oxygen-containing gas supply equipment for supplying a gas containing oxygen, further comprising an oxidation inhibitor supply equipment for supplying an oxidation inhibitor into the absorption tower. apparatus.
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| JP2002150888A JP3836048B2 (en) | 2002-05-24 | 2002-05-24 | Wet flue gas desulfurization method and apparatus |
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