JP3354660B2 - Exhaust gas treatment method - Google Patents
Exhaust gas treatment methodInfo
- Publication number
- JP3354660B2 JP3354660B2 JP26056193A JP26056193A JP3354660B2 JP 3354660 B2 JP3354660 B2 JP 3354660B2 JP 26056193 A JP26056193 A JP 26056193A JP 26056193 A JP26056193 A JP 26056193A JP 3354660 B2 JP3354660 B2 JP 3354660B2
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- gas
- nox
- desulfurization
- denitration
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Landscapes
- Treating Waste Gases (AREA)
- Gas Separation By Absorption (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は石炭焚き排ガスや重質油
燃焼排ガスの如きＮＯｘとＳＯ2 を含む排ガスの処理方
法に関する。The present invention relates to a method of treating exhaust gas containing such NOx and SO 2 in coal gas or heavy oil combustion exhaust gas.
【０００２】[0002]
【従来の技術】排ガス中のＮＯｘの除去法として、排ガ
ス中にＮＨ3 を添加し触媒上で反応させてＮ2 とＨ2 Ｏ
に分解する選択還元脱硝方法（ＳＣＲ法）が火力発電用
ボイラ排ガスなどに広く適用されている。一方、ＳＯ2
の除去法としては石灰石（ＣａＣＯ3 ）を吸収剤として
排ガスのＳＯ2 を吸収除去し、副生品として石膏を回収
する湿式石灰石膏法が広く実用化されている。2. Description of the Related Art As a method for removing NOx from exhaust gas, NH 3 is added to the exhaust gas and reacted on a catalyst to form N 2 and H 2 O.
The selective reduction denitration method (SCR method), which decomposes into gas, is widely applied to boiler exhaust gas for thermal power generation. On the other hand, SO 2
The removal method limestone (CaCO 3) of SO 2 in exhaust gas is absorbed and removed as an absorbent, wet lime-gypsum method for recovering gypsum is widely used as a by-product.
【０００３】[0003]
【発明が解決しようとする課題】前記の脱硝方法は今ま
では脱硝率が８０％程度のところで運用されてきたが、
最近の排ガス規制の強化に伴って、脱硝率９０−１００
％という高効率脱硝の要求がなされ、さらに脱硫におい
ても同様の高効率化のニーズがある。上記要求に応える
べく高効率な脱硝を行なうためには、次式で示す反応当
量以上のＮＨ3 を添加する必要がある。 ４ＮＯ＋４ＮＨ3 ＋Ｏ2 → ４Ｎ2 ＋６Ｈ2 Ｏ ＮＯ＋ＮＯ2 ＋２ＮＨ3 → ２Ｎ2 ＋３Ｈ2 Ｏ しかし、ＮＨ3 の添加量をＮＯｘに対して反応当量以上
にすると、ＮＯｘと反応しない過剰のＮＨ3 が煙突から
排出されることになり、環境上好ましくなく、過剰なＮ
Ｈ3 を還元脱硝反応器後流で除去する新たな装置を導入
する必要がある。The above-mentioned denitration method has been operated at a denitration rate of about 80%.
With the recent tightening of exhaust gas regulations, the denitration rate was 90-100.
%, And there is a demand for the same high efficiency in desulfurization. In order to perform denitration with high efficiency to meet the above demand, it is necessary to add NH 3 in an amount equal to or more than the reaction equivalent shown by the following formula. 4NO + 4NH 3 + O 2 → 4N 2 + 6H 2 O NO + NO 2 + 2NH 3 → 2N 2 + 3H 2 O However, if the added amount of NH 3 is more than the reaction equivalent to NOx, excess NH 3 not reacting with NOx is discharged from the chimney. Environmentally unfriendly and excessive N
It is necessary to introduce a new apparatus for removing H 3 downstream of the denitration reactor.
【０００４】一方、ＣａＣＯ3 を吸収剤とする湿式脱硫
装置においても高効率な脱硫を行うためには次式で示す
反応当量以上に吸収剤であるＣａＣＯ3 を添加する必要
があり、一般式には過剰にＣａＣＯ3 を入れるほど脱硫
率は向上する。 ＳＯ2 ＋ＣａＣＯ3 ＋ 1/2Ｏ2 → ＣａＳＯ4 ＋ＣＯ
2 しかし、脱硝と同様に過剰なＣａＣＯ3 は副生物である
石膏に混入し、石膏の純度を低下させる上、ＣａＣＯ3
の消費増大を招く欠点があった。これを解決する目的で
湿式脱硫装置ではＣａＣＯ3 溶解速度を増加させ、これ
により脱硫率を向上させる各種脱硫助剤が提案されてい
る。On the other hand, in order to perform a highly efficient desulfurization even in a wet desulfurization unit for the CaCO 3 with the absorbent must be added to CaCO 3 is absorbent or reaction equivalent shown by the following formula, the formula The desulfurization rate increases as CaCO 3 is added in excess. SO 2 + CaCO 3 + 1 / 2O 2 → CaSO 4 + CO
2 However, as in the case of denitration, excess CaCO 3 is mixed into gypsum as a by-product, reducing the purity of the gypsum and causing CaCO 3
There is a drawback that leads to an increase in consumption. In order to solve this problem, various desulfurization auxiliaries have been proposed in a wet desulfurization apparatus that increase the CaCO 3 dissolution rate and thereby improve the desulfurization rate.
【０００５】例えば、脱硫助剤として、Ｎａ2 ＳＯ4 、
Ｎａ2 ＳＯ3 、ＮａＯＨ、Ｎａ2 ＣＯ3 、ＮａＨＣ
Ｏ3 、ＮａＨＳＯ3 などのナトリウム化合物を使用する
方法は特開昭６０−８４１３３号公報や特許第８９４７
２５号明細書や特許第９０３２７６号明細書を初め、特
開昭５３−１２９１６７号、特開昭５５−１２４５３０
号、特開昭５６−６５６１５号及び特開昭５１−９７５
９７号各公報において開示されており、マグネシウム化
合物を脱硫助剤とする方法については特開昭５３−１７
５６５号公報により開示されている。しかしながら本発
明の重要な構成であるＮＨ3 ガスを脱硫助剤として使用
する方法については上記公開資料によっても全く触れら
れていない。For example, Na 2 SO 4 ,
Na 2 SO 3 , NaOH, Na 2 CO 3 , NaHC
Methods using sodium compounds such as O 3 and NaHSO 3 are disclosed in JP-A-60-84133 and JP-A-8947.
No. 25, Japanese Patent No. 903276, JP-A-53-129167 and JP-A-55-124530.
JP-A-56-65615 and JP-A-51-975.
No. 97, each of which discloses a method of using a magnesium compound as a desulfurization aid.
No. 565 discloses this. However, there is no mention of the method of using NH 3 gas as a desulfurization aid, which is an important component of the present invention, even in the above-mentioned publication.
【０００６】本発明は前記従来法の欠点を改善すべく、
過剰なＮＨ3 が高効率の脱硝を可能とし、さらにＮＨ3
が高効率な脱硫を可能とすることを見い出し、その結果
として還元脱硝反応器の後流のＮＨ3 除去装置が不要で
あり、かつこの過剰ＮＨ3 を脱硫助剤として使用するこ
とができる高効率な脱硫を備えた排ガスの処理方法を提
供しようとするものである。さらに、本発明では脱硫吸
収液からＮＨ3 を回収し、ＮＨ3 の有効利用も可能とす
る方法を提供しようとするものである。[0006] The present invention aims to remedy the drawbacks of the conventional method.
Excess NH 3 enables high-efficiency denitration, and NH 3
Makes it possible to achieve high-efficiency desulfurization, and as a result, there is no need for an NH 3 removal device downstream of the reductive denitration reactor, and a high efficiency in which this excess NH 3 can be used as a desulfurization aid It is an object of the present invention to provide a method for treating an exhaust gas having a proper desulfurization. Further, the present invention aims to provide a method of recovering NH 3 from a desulfurization absorption liquid and enabling effective use of NH 3 .
【０００７】[0007]
【課題を解決するための手段】本発明は、（１）排ガス
中のＮＯｘを還元触媒を充填した還元脱硝反応装置で脱
硝し、ＳＯ2 を石灰石を吸収剤とする湿式脱硫装置で脱
硫する排ガス処理方法において、排ガス中のＮＯｘとの
反応当量以上のＮＨ3 を前記還元脱硝反応装置の上流の
排ガスに添加して前記還元脱硝反応装置においてＮＯｘ
とＮＨ3 を反応させ、次いで排ガス中に残存するＮＨ3
を含む排ガスを前記湿式脱硫装置へ導き、排ガス中のＳ
Ｏ2 を除去することを特徴とする排ガスの処理方法、及
び（２）湿式脱硫装置の吸収液の一部を系外に排出する
過程で、吸収液ｐＨを１０以上に予め調整後加熱して吸
収液よりＮＨ3 をガスとして回収する工程と、回収した
ＮＨ3 ガスを排ガス中のＮＯｘと反応させるために添加
使用するＮＨ3 ガスの一部として供給することを特徴と
する上記（１）記載の排ガスの処理方法である。SUMMARY OF THE INVENTION The present invention, exhaust gas desulfurization by the wet desulfurization apparatus according to (1) denitration by reduction denitration reactor the NOx in the exhaust gas was charged with reduction catalyst absorber limestone SO 2 in the processing method, NOx in the reduction denitration reactor was added upstream of the exhaust gas of the NH 3 above reaction equivalent of the NOx in the exhaust gas the reducing denitration reactor
With NH 3 and then NH 3 remaining in the exhaust gas
To the wet desulfurization unit, and the S in the exhaust gas
An exhaust gas treatment method characterized by removing O 2 ,
And (2) a step of preliminarily adjusting the pH of the absorbing solution to 10 or more and heating it to recover NH 3 as a gas from the absorbing solution in the process of discharging a part of the absorbing solution of the wet desulfurization device outside the system. NH 3 gas is how to process the exhaust gas (1) above, wherein the feeding as part of the NH 3 gas used added to react with NOx in the exhaust gas.
【０００８】[0008]
【作用】前記本発明（１）においては、ＮＯｘの還元脱
硝反応器の上流において排ガス中のＮＯｘとの反応当量
以上のＮＨ3 を排ガスに添加することによって、ＮＯｘ
の還元脱硝反応器においては排ガス中のＮＯｘが充分に
かつ、高効率に脱硝される。ＮＯｘの還元脱硝反応器を
出た排ガス中に残存するＮＨ3 は湿式脱硫装置へ導か
れ、湿式脱硫装置の吸収液に吸収される。吸収液に吸収
されたＮＨ3 はアンモニウム塩として吸収液中に溶解す
る。このアンモニウム塩が従来使用されていたナトリウ
ム塩やマグネシウム塩の脱硫助剤としての効果に比べて
著しく高い効果を示すことを新たに見い出した。In [act] The present invention (1), by the NH 3 above reaction equivalent of the NOx in the exhaust gas upstream of the reducing denitration reactor NOx added to the exhaust gas, NOx
In the reduction denitration reactor, NOx in the exhaust gas is sufficiently and efficiently denitrated. NH 3 remaining in the exhaust gas that has exited the NOx reduction denitration reactor is led to the wet desulfurization unit, and is absorbed by the absorption liquid of the wet desulfurization unit. NH 3 absorbed in the absorbing solution is dissolved in the absorbing solution as an ammonium salt. It has been newly found that this ammonium salt has a remarkably higher effect than the effect of a conventionally used sodium salt or magnesium salt as a desulfurization aid.
【０００９】そこで、本発明の根幹をなす、アンモニウ
ム塩共存時のＣａＣＯ3 溶解作用の促進効果を図３をも
って説明する。図３は本発明の出願人と同一グループが
学会誌に発表｛ J.Chem,Eng.Japan,26 , 112 (1993) ｝
して公知となっている方法により、吸収液中の塩濃度が
石灰石の溶解速度に及ぼす影響検討した結果である。す
なわち、各種塩を溶解した溶液中に一定濃度（０．１モ
ル／リットル）となるようＣａＣＯ3 の粉体を加え、こ
の溶液のｐＨが一定（５．２）となるよう硫酸を加えて
いったときの、硫酸添加速度からＣａＣＯ3 の溶解速度
を測定したものである。図３において、縦軸は塩を加え
ない場合に対する塩を加えた場合のＣａＣＯ3 の溶解速
度の比を示したものである。横軸は各種塩の濃度を示し
たものである。図３から明らかなようにアンモニウム塩
は従来知られているナトリウム塩やマグネシウム塩のよ
うな脱硫助剤と異なり、低濃度でも石灰石の溶解速度を
大幅に増大する作用のあることが明らかである。本発明
（１）は上記の事実に基づいてなされたものである。The effect of promoting the CaCO 3 dissolving effect in the presence of an ammonium salt, which is the basis of the present invention, will be described with reference to FIG. FIG. 3 shows the same group as the applicant of the present invention published in a journal. J. Chem, Eng. Japan, 26, 112 (1993).
This is a result of examining the effect of the salt concentration in the absorbing solution on the dissolution rate of limestone by a known method. That is, powder of CaCO 3 was added to a solution in which various salts were dissolved so as to have a constant concentration (0.1 mol / liter), and sulfuric acid was added so that the pH of the solution was constant (5.2). The dissolution rate of CaCO 3 was measured from the rate of addition of sulfuric acid. In FIG. 3, the vertical axis indicates the ratio of the dissolution rate of CaCO 3 when a salt is added to the case where no salt is added. The horizontal axis shows the concentrations of various salts. As is clear from FIG. 3, the ammonium salt is different from the conventionally known desulfurization aids such as sodium salt and magnesium salt, and has an effect of greatly increasing the dissolution rate of limestone even at a low concentration. The present invention (1) has been made based on the above facts.
【００１０】前記本発明（２）においては、前記本発明
（１）の作用に加えて、湿式脱硫装置の吸収液の一部を
系外に排出する過程で、吸収液ｐＨを１０以上に予め調
整後加熱することにより、吸収液に溶解していたアンモ
ニウム塩がＮＨ3 ガスとなって放散する。これを回収
し、前記ＮＯｘの還元脱硝反応器の上流の排ガス中に供
給し、これによってＮＨ3 が有効に利用される。In the present invention (2), in addition to the operation of the present invention (1), the pH of the absorbing solution is set to 10 or more in the process of discharging a part of the absorbing solution of the wet desulfurization device out of the system. By heating after the adjustment, the ammonium salt dissolved in the absorbing solution becomes NH 3 gas and diffuses. This is recovered and supplied to the exhaust gas upstream of the NOx reduction denitration reactor, whereby NH 3 is effectively used.
【００１１】[0011]
（実施例１）本発明の一実施例を図１によって説明す
る。この実施例１は石炭焚き排ガスの処理方法に係わる
ものである。ボイラ１からの燃焼排ガスの流路にはアン
モニアタンク２から供給されるＮＨ3 を排ガスに注入す
るＮＨ3 注入部３が設置されている。ＮＨ3 が注入され
た排ガスは還元脱硝反応器４へ導かれ、ここで脱硝が行
われる。還元脱硝反応器４には還元触媒が充填されてお
り、この触媒としては酸化チタンを担体としたバナジウ
ム、モリブデン、タングステン系などの触媒を使用する
ことができる。還元脱硝反応器４の後流には、空気加熱
器５及び電気集塵器６が設置されているが、この２つの
機器は本発明が目的とする脱硝及び脱硫には関係なく、
各々ボイラへ供給する空気の加熱と排ガスからの集塵を
目的としており、本発明の構成要素ではない。(Embodiment 1) An embodiment of the present invention will be described with reference to FIG. The first embodiment relates to a method for treating coal-fired exhaust gas. In the flow path of the combustion exhaust gas from the boiler 1, an NH 3 injection unit 3 for injecting NH 3 supplied from the ammonia tank 2 into the exhaust gas is installed. The exhaust gas into which NH 3 has been injected is led to the reduction denitration reactor 4, where the denitration is performed. The reduction denitration reactor 4 is filled with a reduction catalyst, and a vanadium, molybdenum, tungsten-based catalyst using titanium oxide as a carrier can be used as the catalyst. An air heater 5 and an electrostatic precipitator 6 are installed downstream of the reduction denitration reactor 4, and these two devices are not related to the denitration and desulfurization aimed at by the present invention.
Each of them aims at heating air supplied to the boiler and collecting dust from exhaust gas, and is not a component of the present invention.
【００１２】電気集塵器６の後流には湿式脱硫装置７が
設置されている。ここでは、ＳＯ2の吸収剤であるＣａ
ＣＯ3 を含む懸濁液（スラリ）が循環しており、排ガス
との気液接触により排ガスからＳＯ2 が吸収除去され
る。さらに、本発明では還元脱硝反応器４で過剰となっ
たＮＨ3 が排ガスとともに湿式脱硫装置に到達し、ＳＯ
2 と同様にスラリ中へ吸収される。吸収されたＮＨ3 は
スラリ中にアンモニウム塩として吸収剤であるＣａＣＯ
3 と共存する。A wet desulfurizer 7 is provided downstream of the electrostatic precipitator 6.
is set up. Here, SOTwoCa as an absorbent
COThreeSuspension (slurry) containing
From the exhaust gas by gas-liquid contact with SOTwoIs absorbed and removed
You. Further, in the present invention, the excess amount is
NHThreeReaches the wet desulfurization unit together with the exhaust gas,
TwoIs absorbed into the slurry as well. NH absorbedThreeIs
CaCO as an absorbent as an ammonium salt in the slurry
ThreeCoexist with
【００１３】表１に本発明の効果を確認するために実施
した前記実施例のパイロットプラントのテスト条件を示
す。 表１ パイロットプラントテスト条件 （１）排ガス条件 排ガス源 ： 微粉炭燃焼排ガス 処理ガス流量 ： ２００Ｎｍ3 ／ｈ（ドライ
ベース） 排ガスのＳＯ2 濃度 ： ８００ｐｐｍ（ドライベー
ス） 排ガスのＮＯｘ濃度 ： ２５０ｐｐｍ（ドライベー
ス） （２）還元脱硝反応器条件 ＮＨ3 ／ＮＯｘモル比 ： １．１ （３）湿式脱硫装置条件 吸収剤 ： ＣａＣＯ3 （３２５メッシ
ュ９０％通過の粉体） 吸収塔液ガス比 ： １７．５リットル／Ｎｍ3 スラリ設定ｐＨ ： ６．３Table 1 shows the test conditions of the pilot plant of the above embodiment, which were carried out to confirm the effect of the present invention. Table 1 Pilot plant test conditions (1) Exhaust gas conditions Exhaust gas source: Pulverized coal combustion exhaust gas Processing gas flow rate: 200 Nm 3 / h (dry base) SO 2 concentration in exhaust gas: 800 ppm (dry base) NOx concentration in exhaust gas: 250 ppm (dry base) (2) Reducing denitration reactor conditions NH 3 / NOx molar ratio: 1.1 (3) Wet desulfurization device conditions Absorbent: CaCO 3 (powder passing 325 mesh 90%) Absorption tower liquid gas ratio: 17.5 Liter / Nm 3 slurry setting pH: 6.3
【００１４】以上の条件で排ガスを処理したときの脱硝
率及び脱硫率は以下のとおりとなった。 脱硝率 ： ９５％以上 脱硫率 ： ９８．５％The denitration rates and desulfurization rates when the exhaust gas was treated under the above conditions were as follows. Denitration rate: 95% or more Desulfurization rate: 98.5%
【００１５】比較のため、還元脱硝反応器で排ガス中の
ＮＯｘと反応当量以下のＮＨ3 を添加する運転、すなわ
ち、ＮＨ3 ／ＮＯｘモル比０．９の条件で、かつそれ以
外の運転条件は表１と同一とした場合、脱硝率及び脱硫
率は以下のとおりとなった。 脱硝率 ： ８２％ 脱硫率 ： ９２．５％For comparison, an operation in which NO 3 in the exhaust gas is added in an amount equal to or less than the reaction equivalent of NH 3 in the reductive denitration reactor, that is, an NH 3 / NOx molar ratio of 0.9, and other operating conditions are as follows. When the same as in Table 1, the denitration rate and desulfurization rate were as follows. Denitration rate: 82% Desulfurization rate: 92.5%
【００１６】（実施例２）本発明の他の実施例２を図２
に基づいて説明する。この実施例は実施例１の湿式脱硫
装置７の吸収液からＮＨ3 ガスを回収する工程と回収し
たＮＨ3 ガスを排ガスの添加に使用するＮＨ3 ガスの一
部として供給する工程を付加したものであり、実施例１
と重複する説明は省略する。(Embodiment 2) FIG. 2 shows another embodiment 2 of the present invention.
It will be described based on. This embodiment is obtained by adding the process of supplying NH 3 gas and recovery step of recovering the NH 3 gas from the absorption liquid of a wet desulfurization apparatus 7 of Example 1 as a part of the NH 3 gas used the addition of exhaust gas Example 1
Descriptions that are the same as those described above are omitted.
【００１７】湿式脱硫装置７では前記のとおり、脱硫の
ためＣａＣＯ3 を含む吸収液を使用しているが、脱硫に
よって次式のように石膏が生成するため吸収液の一部が
抜き出されている。 ＳＯ2 ＋ＣａＣＯ3 ＋ 1/2Ｏ2 → ＣａＳＯ4 ＋ＣＯ
2 抜き出しライン９によって抜き出された吸収液は遠心分
離器などの固液分離器１０で石膏１１が分離される。一
方、分離ろ液の大部分は湿式脱硫装置７へ戻されるが、
その一部はｐＨ調整槽１２に供給され、ここで強アルカ
リによってｐＨが１０以上に調整された後、加熱装置１
３に送液され、ここでろ液中のアンモニウム塩はＮＨ3
ガスとして回収され、ライン１４により還元脱硝反応器
４の上流に注入される。強アルカリとしてはＣａ（Ｏ
Ｈ）2 あるいはＮａＯＨなどが使用可能でこの際の中和
反応と加熱によるＮＨ3 ガスの回収は以下の反応式で表
せる。 〇中和反応 ２ＮＨ4 Ｘ＋Ｃａ（ＯＨ）2 →２ＮＨ4 ＯＨ＋ＣａＸ2 ＮＨ4 Ｘ＋ＮａＯＨ → ＮＨ4 ＯＨ＋ＮａＸ Ｘはアニオンを示す。 〇ＮＨ3 ガス回収 ＮＨ4 ＯＨ → ＮＨ3 ＋ Ｈ2 Ｏ 加熱装置からライン１５を経て排出される液は、必要に
応じて排水処理を行った後、系外に排出される。As described above, in the wet desulfurization apparatus 7, an absorbent containing CaCO 3 is used for desulfurization. However, a part of the absorbent is withdrawn because gypsum is formed by the following equation. I have. SO 2 + CaCO 3 + 1 / 2O 2 → CaSO 4 + CO
2 The gypsum 11 is separated from the absorption liquid extracted by the extraction line 9 by a solid-liquid separator 10 such as a centrifuge. On the other hand, most of the separated filtrate is returned to the wet desulfurization unit 7,
A part thereof is supplied to a pH adjusting tank 12, where the pH is adjusted to 10 or more by a strong alkali.
3 where the ammonium salt in the filtrate is NH 3
The gas is recovered as a gas and injected into the upstream of the reductive denitration reactor 4 by a line 14. As a strong alkali, Ca (O
H) 2 or NaOH can be used. In this case, the neutralization reaction and the recovery of NH 3 gas by heating can be represented by the following reaction formula. 〇Neutralization reaction 2NH 4 X + Ca (OH) 2 → 2NH 4 OH + CaX 2 NH 4 X + NaOH → NH 4 OH + NaX X indicates an anion. 〇NH 3 gas recovery The liquid discharged from the NH 4 OH → NH 3 + H 2 O heating device via the line 15 is subjected to drainage treatment as required, and then discharged out of the system.
【００１８】前記装置で実施例１の表１に示すテスト条
件で運転した結果、脱硝率及び脱硫率は実施例１と同様
で以下のとおりであった。 脱硝率 ： ９５％以上 脱硫率 ： ９８．５％ さらに、実施例２では実施例１に比較し、以下に示すよ
うにＮＨ3 使用量が低減できた。 ＮＨ3 使用量（実施例１） ： ２．５モル／リットル ＮＨ3 使用量（実施例２） ： ２．２モル／リットルAs a result of operating the above apparatus under the test conditions shown in Table 1 of Example 1, the denitration rate and desulfurization rate were the same as in Example 1 and were as follows. Denitration rate: 95% or more Desulfurization rate: 98.5% Further, in Example 2, as compared with Example 1, the amount of NH 3 used could be reduced as shown below. NH 3 usage (Example 1): 2.5 mol / L NH 3 usage (Example 2): 2.2 mol / L
【００１９】[0019]
【発明の効果】アンモニウム塩の脱硫助剤としての顕著
な効果に注目した本発明の方法を適用することにより、
従来方法に比較し、経済的に有利な方法で高効率な脱硝
と脱硫を同時に達成することが可能となった。さらに、
脱硫助剤であるＮＨ3 ガスを湿式脱硫装置の吸収液から
回収し、循環利用することで、系外から供給するＮＨ3
量を低減することが可能となった。According to the method of the present invention, which focuses on the remarkable effect of an ammonium salt as a desulfurization aid,
Compared with the conventional method, it has become possible to simultaneously achieve highly efficient denitration and desulfurization in an economically advantageous manner. further,
NH 3 gas, which is a desulfurization aid, is recovered from the absorption liquid of the wet desulfurization unit and circulated and used to supply NH 3 gas from outside the system.
The amount can be reduced.
【図１】本発明（１）の一実施態様の説明図。FIG. 1 is an explanatory view of one embodiment of the present invention (1).
【図２】本発明（２）の一実施態様の説明図。FIG. 2 is an explanatory view of one embodiment of the present invention (2).
【図３】アンモニウム塩共存時の石灰石溶解作用の促進
効果を示す図表。FIG. 3 is a table showing the effect of promoting the limestone dissolving action in the presence of an ammonium salt.
フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｂ０１Ｄ 53/86 ＺＡＢ Ｂ０１Ｄ 53/36 １０１Ｚ 53/94 (72)発明者 田中 裕士 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 (72)発明者 筒井 浩養 東京都千代田区丸の内二丁目５番１号 三菱重工業株式会社本社内 (56)参考文献 特開 昭51−146368（ＪＰ，Ａ) 特開 昭50−9569（ＪＰ，Ａ) 特開 昭51−26678（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B01D 53/34 B01D 53/14 Continued on the front page. (51) Int.Cl. 7 Identification code FI B01D 53/86 ZAB B01D 53/36 101Z 53/94 (72) Inventor Yuji Tanaka 4-6-22 Kanonshinmachi, Nishi-ku, Hiroshima-shi, Hiroshima, Japan Mitsubishi Heavy Industries Hiroshima Research Laboratory Co., Ltd. (72) Inventor Hiroyasu Tsutsui 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Heavy Industries, Ltd. (56) References JP-A-51-146368 (JP, A) JP-A-50 -9569 (JP, A) JP-A-51-26678 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) B01D 53/34 B01D 53/14
Claims (2)
還元脱硝反応装置で脱硝し、ＳＯ2 を石灰石を吸収剤と
する湿式脱硫装置で脱硫する排ガス処理方法において、
排ガス中のＮＯｘとの反応当量以上のＮＨ3 を前記還元
脱硝反応装置の上流の排ガスに添加して前記還元脱硝反
応装置においてＮＯｘとＮＨ3 を反応させ、次いで排ガ
ス中に残存するＮＨ3 を含む排ガスを前記湿式脱硫装置
へ導き、排ガス中のＳＯ2 を除去することを特徴とする
排ガスの処理方法。An exhaust gas treatment method for denitrifying NOx in exhaust gas with a reduction denitration reactor filled with a reduction catalyst and desulfurizing SO 2 with a wet desulfurization device using limestone as an absorbent.
Of NH 3 more than the reaction equivalent of the NOx in the exhaust gas is added to the exhaust gas upstream of the reducing denitration reactor by reacting NOx with NH 3 in the reducing denitration reactor, and then includes the NH 3 remaining in the exhaust gas A method for treating exhaust gas, comprising: introducing exhaust gas to the wet desulfurization device to remove SO 2 in the exhaust gas.
出する過程で、吸収液ｐＨを１０以上に予め調整後加熱
して吸収液よりＮＨ3 をガスとして回収する工程と、回
収したＮＨ3 ガスを排ガス中のＮＯｘと反応させるため
に添加使用するＮＨ3 ガスの一部として供給することを
特徴とする請求項１に記載の排ガスの処理方法。2. A process of recovering NH 3 as a gas from the absorbing solution by adjusting the pH of the absorbing solution in advance to 10 or more and heating it in the process of discharging a part of the absorbing solution of the wet desulfurization device out of the system processing method of an exhaust gas according to claim 1, wherein the the NH 3 gas and supplying a part of the NH 3 gas used added to react with NOx in the exhaust gas.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26056193A JP3354660B2 (en) | 1993-10-19 | 1993-10-19 | Exhaust gas treatment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26056193A JP3354660B2 (en) | 1993-10-19 | 1993-10-19 | Exhaust gas treatment method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07112117A JPH07112117A (en) | 1995-05-02 |
| JP3354660B2 true JP3354660B2 (en) | 2002-12-09 |
Family
ID=17349670
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26056193A Expired - Fee Related JP3354660B2 (en) | 1993-10-19 | 1993-10-19 | Exhaust gas treatment method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3354660B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011074230A1 (en) | 2009-12-14 | 2011-06-23 | バブコック日立株式会社 | Method for removing mercury from combustion gas, and combustion gas cleaner |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3420949B2 (en) | 1997-12-25 | 2003-06-30 | キヤノン株式会社 | Soil purification device and method for repairing contaminated soil |
| US6863875B1 (en) | 1998-04-13 | 2005-03-08 | Mitsubishi Heavy Industries, Ltd. | Flue gas treating system and process |
| FR2800298B1 (en) * | 1999-10-29 | 2002-01-11 | Sud Ouest Travaux | PROCESS FOR THE PURIFICATION OF EXHAUST GASES FROM HEAT ENGINES |
-
1993
- 1993-10-19 JP JP26056193A patent/JP3354660B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011074230A1 (en) | 2009-12-14 | 2011-06-23 | バブコック日立株式会社 | Method for removing mercury from combustion gas, and combustion gas cleaner |
| US8372363B2 (en) | 2009-12-14 | 2013-02-12 | Babcock-Hitachi Kabushiki Kaisha | Method of mercury removal from combustion exhaust gas and combustion exhaust gas purification apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07112117A (en) | 1995-05-02 |
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