JPH07112117A - Waste gas treatment - Google Patents
Waste gas treatmentInfo
- Publication number
- JPH07112117A JPH07112117A JP5260561A JP26056193A JPH07112117A JP H07112117 A JPH07112117 A JP H07112117A JP 5260561 A JP5260561 A JP 5260561A JP 26056193 A JP26056193 A JP 26056193A JP H07112117 A JPH07112117 A JP H07112117A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- waste gas
- gas
- desulfurization
- nox
- 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.)
- Granted
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)
Abstract
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。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating exhaust gas containing NOx and SO 2 such as coal-fired exhaust gas and 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 exhaust gas and reacted on a catalyst to produce N 2 and H 2 O.
The selective reduction denitration method (SCR method), which decomposes into the above, is widely applied to exhaust gas from boilers for thermal power generation. On the other hand, SO 2
As a method for removing the above, a wet lime gypsum method in which SO 2 of exhaust gas is absorbed and removed using limestone (CaCO 3 ) as an absorbent and gypsum is recovered as a by-product has been widely put into practical use.
【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 used until now at a denitration rate of about 80%.
With recent tightening of exhaust gas regulations, denitration rate 90-100
%, There is a demand for high-efficiency denitration, and there is a similar need for higher efficiency in desulfurization. In order to perform highly efficient denitration to meet the above requirements, it is necessary to add more than the reaction equivalent of NH 3 represented 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 amount of NH 3 added is more than the reaction equivalent to NOx, excess NH 3 that does not react with NOx is discharged from the stack. Is unfavorable for the environment, and excessive N
It is necessary to introduce a new device for removing H 3 in the downstream of the reduction 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 higher the CaCO 3 content, the higher the desulfurization rate. SO 2 + CaCO 3 + 1 / 2O 2 → CaSO 4 + CO
2 However, as in the case of denitration, excess CaCO 3 mixes with gypsum, which is a by-product, and reduces the purity of gypsum, and CaCO 3
However, there is a drawback that increases the consumption of. For the purpose of solving this, various desulfurization aids have been proposed which increase the rate of CaCO 3 dissolution in a wet desulfurization apparatus 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, as a desulfurization aid, Na 2 SO 4 ,
Na 2 SO 3 , NaOH, Na 2 CO 3 , NaHC
A method using a sodium compound such as O 3 and NaHSO 3 is disclosed in JP-A-60-84133 and JP-A-8947.
No. 25 and No. 903276, as well as JP-A-53-129167 and JP-A-55-124530.
JP-A-56-65615 and JP-A-51-975.
JP-A-53-17 discloses a method of using a magnesium compound as a desulfurization aid, which is disclosed in each of Japanese Patent Publication No. 97.
It is disclosed by Japanese Patent Publication No. 565. However, even the method of using NH 3 gas as a desulfurization aid, which is an important constitution of the present invention, is not touched at all by 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。The present invention aims to remedy the drawbacks of the prior art methods described above.
Excess NH 3 enables highly efficient denitration, and further NH 3
Has been found to enable highly efficient desulfurization, and as a result, a NH 3 removal device in the downstream of the reduction denitration reactor is unnecessary, and this excess NH 3 can be used as a desulfurization auxiliary agent with high efficiency. The present invention aims to provide a method for treating exhaust gas provided with various desulfurization. Further, the present invention is intended to provide a method for recovering NH 3 from the 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ＮＨ
3 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。 （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Ｎ
Ｈ3 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。Means for Solving the Problems (1) NOx in exhaust gas is denitrified by a reduction denitration reactor,
In the exhaust gas treatment method in which SO 2 is desulfurized by a wet desulfurization device using limestone as an absorbent, the reduction denitration reaction is performed by adding NH 3 in an amount equal to or more than a reaction equivalent of NOx in the exhaust gas to the exhaust gas upstream of the reduction denitration reaction device. NOx and NH in the device
A method for treating exhaust gas, which comprises reacting 3 and then introducing the exhaust gas containing NH 3 remaining in the exhaust gas to the wet desulfurization apparatus to remove SO 2 in the exhaust gas. (2) In the process of discharging a part of the absorption liquid of the wet desulfurization apparatus to the outside of the system, a step of previously adjusting the absorption liquid pH to 10 or more and then heating to recover NH 3 as a gas from the absorption liquid, and a recovered N
The method for treating exhaust gas according to the above (1), wherein the H 3 gas is supplied as a part of the NH 3 gas added and used to react with NOx in the exhaust gas. Is.
【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, the NOx in the exhaust gas is sufficiently and efficiently denitrated. NH 3 remaining in the exhaust gas leaving the NOx reduction denitration reactor is guided to the wet desulfurization device and absorbed by the absorption liquid of the wet desulfurization device. NH 3 absorbed in the absorbing solution is dissolved in the absorbing solution as an ammonium salt. It was newly found that this ammonium salt exhibits a remarkably high effect as compared with the effect of the desulfurization aid of the sodium salt or magnesium salt which has been conventionally used.
【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。Therefore, the effect of promoting the CaCO 3 dissolution action in the presence of an ammonium salt, which is the basis of the present invention, will be described with reference to FIG. Fig. 3 is published in the journal of the academic society by the same group as the applicant of the present invention {J.Chem, Eng.Japan, 26, 112 (1993)}
It is the result of examining the effect of the salt concentration in the absorbing solution on the dissolution rate of limestone by a method known to the public. That is, CaCO 3 powder 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 this solution was constant (5.2). The dissolution rate of CaCO 3 was measured from the addition rate of sulfuric acid at that time. In FIG. 3, the vertical axis shows the ratio of the dissolution rate of CaCO 3 when salt is added to when no salt is added. The horizontal axis shows the concentrations of various salts. As is clear from FIG. 3, unlike the conventionally known desulfurization aids such as sodium salts and magnesium salts, it is clear that the ammonium salt has an action of significantly 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 function of the present invention (1), in the process of discharging a part of the absorption liquid of the wet desulfurization apparatus out of the system, the absorption liquid pH is set to 10 or more in advance. By heating after the adjustment, the ammonium salt dissolved in the absorption liquid becomes NH 3 gas and is diffused. This is recovered and supplied into the exhaust gas upstream of the NOx reduction and 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. Example 1 relates to a method for treating coal-fired exhaust gas. An NH 3 injection unit 3 for injecting NH 3 supplied from the ammonia tank 2 into the exhaust gas is installed in the flow path of the combustion exhaust gas from the boiler 1. The exhaust gas into which NH 3 has been injected is guided to the reduction denitration reactor 4 where denitration is performed. The reduction denitration reactor 4 is filled with a reduction catalyst, and as the catalyst, a vanadium, molybdenum, or tungsten-based catalyst having titanium oxide as a carrier can be used. An air heater 5 and an electrostatic precipitator 6 are installed downstream of the reduction denitration reactor 4, but these two devices are not related to the denitration and desulfurization intended by the present invention.
Each is intended to heat the air supplied to the boiler and to collect dust from the exhaust gas, and is not a constituent element 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 desulfurization device 7 is provided downstream of the electrostatic precipitator 6.
is set up. Here, SO2Is an absorbent of Ca
CO3Exhaust gas that circulates a suspension (slurry) containing
SO from the exhaust gas by gas-liquid contact with2Are absorbed and removed
It Further, in the present invention, the excess is reduced in the reduction denitration reactor 4.
NH3Reaches the wet desulfurization unit together with the exhaust gas, and SO
2Is absorbed into the slurry as well as. Absorbed NH3Is
CaCO as an absorbent as ammonium salt in the slurry
3Coexist 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-mentioned embodiment 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 Treatment gas flow rate: 200 Nm 3 / h (dry base) SO 2 concentration of exhaust gas: 800 ppm (dry base) NOx concentration of exhaust gas: 250 ppm (dry base) ) (2) Reductive denitration reactor conditions NH 3 / NOx molar ratio: 1.1 (3) Wet desulfurization device conditions Absorbent: CaCO 3 (powder of 325 mesh 90% passage) Absorption tower liquid gas ratio: 17.5 L / Nm 3 slurry set 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 rate and desulfurization rate 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, the operation of adding NOx in the exhaust gas and NH 3 at a reaction equivalent or less in the reduction denitration reactor, that is, the condition of NH 3 / NOx molar ratio of 0.9, and other operating conditions are When the same as in Table 1, the denitration rate and the desulfurization rate are 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) Another embodiment 2 of the present invention is shown in FIG.
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 And Example 1
The description overlapping with that is 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, the wet desulfurization apparatus 7 uses an absorbing solution containing CaCO 3 for desulfurization. However, since desulfurization produces gypsum as shown in the following formula, a part of the absorbing solution is extracted. There is. 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 centrifugal separator. On the other hand, most of the separated filtrate is returned to the wet desulfurization device 7,
Part of it is supplied to the pH adjusting tank 12, where the pH is adjusted to 10 or more by a strong alkali, and then the heating device 1
The ammonium salt in the filtrate is NH 3
It is recovered as a gas and is injected upstream of the reduction denitration reactor 4 through the line 14. Ca (O
H) 2 or NaOH can be used. At this time, the neutralization reaction and the NH 3 gas recovery by heating can be expressed by the following reaction formula. ○ Neutralization reaction 2NH 4 X + Ca (OH) 2 → 2NH 4 OH + CaX 2 NH 4 X + NaOH → NH 4 OH + NaX X represents an anion. ○ NH 3 gas recovery NH 4 OH → NH 3 + H 2 O The liquid discharged from the heating device through the line 15 is discharged to the outside of the system after performing wastewater treatment as necessary.
【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 apparatus under the test conditions shown in Table 1 of Example 1, the denitration rate and the 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, the amount of NH 3 used could be reduced as compared with Example 1 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。By applying the method of the present invention which pays attention to the remarkable effect of ammonium salt as a desulfurization aid,
Compared with the conventional method, it has become possible to simultaneously achieve highly efficient denitration and desulfurization with an economically advantageous method. further,
NH 3 gas, which is a desulfurization aid, is recovered from the absorption liquid of the wet desulfurization unit and circulated for supply of NH 3 gas from outside the system.
It has become possible to reduce the amount.
【図１】本発明（１）の一実施態様の説明図。FIG. 1 is an explanatory diagram of an 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 diagram of an 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 diagram showing a promoting effect of limestone dissolution action in the presence of ammonium salt.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｂ０１Ｄ 53/50 53/77 53/86 ＺＡＢ 53/94 Ｂ０１Ｄ 53/34 １２５ Ｅ 53/36 ＺＡＢ １０１ Ｚ (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─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI Technical indication B01D 53/50 53/77 53/86 ZAB 53/94 B01D 53/34 125 E 53/36 ZAB 101 Z (72) Inventor Hiroshi Tanaka 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Research Institute (72) Inventor Hiroyo Tsutsui 2-5-1, Marunouchi, Chiyoda-ku, Tokyo Sanbishi Heavy Industries In-house company
Claims (2)
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ＮＯ
ｘとＮＨ3 を反応させ、次いで排ガス中に残存するＮＨ
3 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。1. In an exhaust gas treatment method in which NOx in exhaust gas is denitrified by a reductive denitration reaction device and SO 2 is desulfurized by a wet desulfurization device using limestone as an absorbent, a reaction equivalent to or more than NO 3 in the exhaust gas of NH 3 is used. Is added to the exhaust gas upstream of the reduction denitration reactor to generate NO in the reduction denitration reactor.
x reacts with NH 3 , and then NH remaining in the exhaust gas
A method for treating exhaust gas, which comprises introducing exhaust gas containing 3 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 step of recovering NH 3 as a gas from the absorbing solution by heating after previously adjusting the absorbing solution pH to 10 or more in the process of discharging a part of the absorbing solution of the wet desulfurization device to the outside of the system, and collecting 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 true JPH07112117A (en) | 1995-05-02 |
| JP3354660B2 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 |
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| Country | Link |
|---|---|
| JP (1) | JP3354660B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1095692A1 (en) * | 1999-10-29 | 2001-05-02 | Travaux Du Sud-Ouest | Process and installation for purification of exhaust gases from internal combustion engines |
| US6250846B1 (en) | 1997-12-25 | 2001-06-26 | Canon Kabushiki Kaisha | Apparatus for soil purification and remediation method for contaminated soil |
| US6863875B1 (en) | 1998-04-13 | 2005-03-08 | Mitsubishi Heavy Industries, Ltd. | Flue gas treating system and process |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5385114B2 (en) | 2009-12-14 | 2014-01-08 | バブコック日立株式会社 | Combustion exhaust gas mercury removal method and combustion exhaust gas purification device. |
-
1993
- 1993-10-19 JP JP26056193A patent/JP3354660B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6250846B1 (en) | 1997-12-25 | 2001-06-26 | Canon Kabushiki Kaisha | Apparatus for soil purification and remediation method for contaminated soil |
| US6863875B1 (en) | 1998-04-13 | 2005-03-08 | Mitsubishi Heavy Industries, Ltd. | Flue gas treating system and process |
| EP1095692A1 (en) * | 1999-10-29 | 2001-05-02 | Travaux Du Sud-Ouest | Process and installation for purification of exhaust gases from internal combustion engines |
| FR2800298A1 (en) * | 1999-10-29 | 2001-05-04 | Sud Ouest Travaux | PROCESS FOR THE PURIFICATION OF EXHAUST GASES FROM HEAT ENGINES |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3354660B2 (en) | 2002-12-09 |
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