JP2002320819A - Method for treating waste gas - Google Patents
Method for treating waste gasInfo
- Publication number
- JP2002320819A JP2002320819A JP2001127169A JP2001127169A JP2002320819A JP 2002320819 A JP2002320819 A JP 2002320819A JP 2001127169 A JP2001127169 A JP 2001127169A JP 2001127169 A JP2001127169 A JP 2001127169A JP 2002320819 A JP2002320819 A JP 2002320819A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- desulfurization
- concentration
- waste gas
- desulfurizing agent
- 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.)
- Pending
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
- Chimneys And Flues (AREA)
- Treating Waste Gases (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は排ガスの処理方法に
関し、さらに詳しくは脱硝装置と、石灰、石膏、石炭灰
系水和硬化物を脱硫剤とする乾式脱硫装置とを用いて排
ガス中の窒素酸化物（ＮＯｘ）と硫黄酸化物（ＳＯｘ）
を除去する排ガスの処理方法に係り、特に脱硫装置の脱
硫率を高性能に維持するのに好適な排ガスの処理方法に
関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating exhaust gas, and more particularly to a method for treating nitrogen in exhaust gas using a denitrification apparatus and a dry desulfurization apparatus using lime, gypsum, and coal ash hydrated hardened product as a desulfurizing agent. Oxides (NOx) and sulfur oxides (SOx)
TECHNICAL FIELD The present invention relates to a method for treating exhaust gas, and more particularly to a method for treating exhaust gas suitable for maintaining a high desulfurization rate of a desulfurization device.
【０００２】[0002]
【従来の技術】火力発電所等において、化石燃料の燃焼
に伴って発生する排煙中の硫黄酸化物、特に二酸化硫黄
（ＳＯ2 ）は、大気汚染や酸性雨等の地球的環境問題の
主原因の１つとなっている。このため、排煙中からＳＯ
2 を除去する排煙脱硫法の研究および脱硫装置の開発は
きわめて重要な課題である。我が国における脱硫法の主
流は湿式法（石灰石・石膏法）であり、この方法は高性
能で信頼性が高いという利点を有するが、大量の水を必
要とし、また排水処理や排ガスの再加熱等が必要である
ため、建設費が安価でかつ運転経費の低減を図ることの
できる新方式の脱硫装置の開発が要望されている。2. Description of the Related Art In thermal power plants and the like, sulfur oxides, particularly sulfur dioxide (SO 2 ), in flue gas generated by the burning of fossil fuels are a major cause of global environmental problems such as air pollution and acid rain. It is one of the causes. For this reason, SO
Research on flue gas desulfurization method to remove 2 and development of desulfurization equipment are very important issues. The mainstream of the desulfurization method in Japan is the wet method (limestone / gypsum method), which has the advantages of high performance and high reliability, but requires a large amount of water, wastewater treatment and reheating of exhaust gas. Therefore, there is a demand for the development of a new type of desulfurization apparatus that can reduce the construction cost and reduce the operation cost.
【０００３】また、火力発電所の燃料として石炭の使用
量が増加するにつれて、排出される石炭灰の処理対策が
課題となっている。我が国では石炭灰はセメントの原料
および混和剤、土木材料分野を中心に利用されている
が、全排出量に対する有効利用率は３０％程度であり、
大部分は埋め立て処分されている。従って、石炭灰を安
価にかつ安定して処理する方策の確立が、発電コストの
低減と環境対策上、重要な鍵となる。また国土が狭く資
源の少ない我が国においては、石炭灰を単なる廃棄物と
して処分するのではなく、資源として利用の拡大を図る
ことが重要な課題といえる。[0003] Further, as the amount of coal used as fuel for thermal power plants increases, there is a need for measures to treat the discharged coal ash. In Japan, coal ash is mainly used in the fields of cement raw materials, admixtures, and civil engineering materials, but the effective utilization rate for total emissions is about 30%.
Most have been landfilled. Therefore, establishment of a method for inexpensively and stably treating coal ash is an important key in reducing power generation costs and environmental measures. In Japan, where land is small and resources are scarce, it is an important issue to expand the use of coal ash as a resource, rather than merely disposing of it as waste.
【０００４】このような背景のもと、特開昭６１−２０
９０３８号公報には、石炭灰を利用た脱硫剤が提案され
ている。この脱硫剤は、基本的には石灰、石膏および石
炭灰からなる原料の混合物に水を加えて混練し、押出し
成型器によりペレット化し、このペレット化した脱硫剤
を養生装置で蒸気養生してカルシウム、石膏およびシリ
コン、アルミニウムの水和物を形成させ、次いでこの水
和物を乾燥機で加熱、脱水して硬化させ、多孔質化する
ことにより得られる。この脱硫剤を用いた乾式脱硫プロ
セスの高効率化を図るには、脱硫剤の高活性化が最も重
要であるが、また脱硫剤へのＳＯ2 の吸収効率を向上さ
せることも重要である。脱硫剤の高活性化に関しては多
数の方法が提案がなされているが、まだ十分満足できる
方法は提案されていない。Under such a background, Japanese Patent Application Laid-Open No. 61-20 / 1986
No. 9038 proposes a desulfurizing agent utilizing coal ash. This desulfurizing agent is prepared by adding water to a mixture of raw materials basically consisting of lime, gypsum and coal ash, kneading the mixture, pelletizing the mixture with an extruder, and steam-curing the pelletized desulfurizing agent with a curing device to obtain calcium. , Gypsum, silicon and aluminum hydrates, and then the hydrates are heated and dehydrated in a drier to harden and become porous. In order to increase the efficiency of the dry desulfurization process using this desulfurizing agent, it is most important to increase the activity of the desulfurizing agent, but it is also important to improve the absorption efficiency of SO 2 into the desulfurizing agent. A number of methods have been proposed for increasing the activity of a desulfurizing agent, but no satisfactory method has yet been proposed.
【０００５】一方、ボイラで発生した排ガス中のＮＯ
ｘ、煤塵およびＳＯｘは、それぞれ排煙脱硝装置、電気
集塵機および排煙脱硫装置によって除去されるが、これ
らは、ボイラ、排煙脱硝装置、排煙脱硫装置（乾式）、
電気集塵機の順に配置されるのが一般的である。図２
は、従来技術における代表的なボイラ排ガス処理装置の
系統図である。図２において、この排ガス処理装置は、
石炭を燃焼するボイラ１と、該ボイラ１から発生した排
ガス中のＮＯｘを除去する脱硝装置２と、ＮＯｘが除去
された排ガス中のＳＯｘを除去する脱硫吸収塔４と、脱
硫吸収塔４に供給する脱硫剤を製造する脱硫剤製造装置
９と、ＳＯｘが除去された排ガス中のばい塵を除去する
電気集塵器５とから主として構成される。On the other hand, NO in exhaust gas generated in a boiler
x, dust and SOx are respectively removed by a flue gas denitrification device, an electric dust collector and a flue gas desulfurization device, which are a boiler, a flue gas denitration device, a flue gas desulfurization device (dry type),
It is common to arrange in order of the electric dust collector. FIG.
1 is a system diagram of a typical boiler exhaust gas treatment device in the prior art. In FIG. 2, this exhaust gas treatment device
Boiler 1 for burning coal, denitration device 2 for removing NOx in exhaust gas generated from boiler 1, desulfurization absorption tower 4 for removing SOx in exhaust gas from which NOx has been removed, and supply to desulfurization absorption tower 4 It mainly comprises a desulfurizing agent manufacturing device 9 for manufacturing a desulfurizing agent to be removed and an electric precipitator 5 for removing soot and dust in the exhaust gas from which SOx has been removed.
【０００６】このような構成において、ボイラ１で発生
した排ガスは、まず脱硝装置２に導かれて該排ガス中の
ＮＯｘが除去される。該脱硝装置２にはアンモニア注入
ライン１６からアンモニアが供給され、触媒の存在下に
排ガス中のＮＯｘが接触還元され、除去される。ＮＯｘ
が除去された排ガスは、空気予熱器３に導かれ、ボイラ
に供給する空気との間で熱交換が行われて約１３０℃に
冷却された後、排ガスライン１１を経て脱硫吸収塔４に
導入される。この脱硫吸収塔４は、前置吸収塔Ａと主吸
収塔Ｂに分割されており、排ガス中の粒子の大きい煤塵
は前置吸収塔Ａで使用済脱硫剤１０とともに捕集され
る。脱硫吸収塔４では、脱硫吸収塔４の入口に設置され
たＳＯ2 分析計７によってＳＯ2 濃度が測定され、この
ＳＯ2 濃度に見合うアルカリ分を有する脱硫剤が供給ラ
イン１２から定量供給される。脱硫吸収塔４で脱硫され
た排ガスは、脱硫吸収塔の出口に設置されたＳＯ2 分析
計８でＳＯ2 濃度が測定された後、電気集塵機５に導か
れ、煤塵が除去され、処理排ガスとして煙突６から大気
に排出される。また上記脱硫剤は、脱硫剤製造装置９で
製造されて供給ライン１２を介して脱硫吸収塔４に供給
される。また脱硫吸収塔４から回収した使用済脱硫剤１
０は粉砕後、その一部が脱硫剤の原料として再利用され
る。In such a configuration, the exhaust gas generated in the boiler 1 is first guided to the denitration device 2 to remove NOx in the exhaust gas. Ammonia is supplied from the ammonia injection line 16 to the denitration device 2, and NOx in the exhaust gas is catalytically reduced and removed in the presence of a catalyst. NOx
The exhaust gas from which is removed is led to the air preheater 3, where it is cooled to about 130 ° C. by heat exchange with the air supplied to the boiler, and then introduced into the desulfurization absorption tower 4 via the exhaust gas line 11. Is done. The desulfurization absorption tower 4 is divided into a pre-absorption tower A and a main absorption tower B, and dust containing large particles in the exhaust gas is collected in the pre-absorption tower A together with the used desulfurization agent 10. In the desulfurization absorption tower 4, the SO 2 concentration is measured by the SO 2 analyzer 7 installed at the inlet of the desulfurization absorption tower 4, and a desulfurizing agent having an alkali content corresponding to the SO 2 concentration is supplied quantitatively from the supply line 12. . The exhaust gas desulfurized in the desulfurization absorption tower 4 is measured for SO 2 concentration by an SO 2 analyzer 8 installed at the outlet of the desulfurization absorption tower, and then guided to an electric precipitator 5 to remove dust and to be treated exhaust gas. The air is discharged from the chimney 6 to the atmosphere. The desulfurizing agent is manufactured by the desulfurizing agent manufacturing device 9 and supplied to the desulfurizing absorption tower 4 via the supply line 12. The used desulfurizing agent 1 recovered from the desulfurization absorption tower 4
After pulverization, a part of 0 is reused as a raw material for a desulfurizing agent.
【０００７】[0007]
【発明が解決しようとする課題】最近、上記乾式脱硫装
置において、ボイラの燃料炭種を変更すると脱硫率が変
化する現象が観察されている。この現象は、脱硫吸収塔
４の脱硫剤に未燃カーボンの多い煤塵が付着した場合や
未燃カーボンの多い石炭灰を使用して脱硫剤を製造した
場合等、燃料炭種による未燃カーボンに起因することが
明らかにされてきているが、上記従来技術では、ボイラ
に供給する燃料炭種による排ガスからの煤塵やＥＰ（電
気集塵器）灰中の未燃カーボンが、脱硫剤の性能に及ぼ
す影響について配慮されておらず、煤塵やＥＰ灰中の未
燃カーボンによって吸収塔での脱硫率が低下するのを防
止することができなかった。本発明の課題は、上記従来
技術の問題点を解決し、ボイラの燃焼条件に影響され
ず、排ガス中の未燃カーボンが脱硫剤に混入または付着
した場合でも高い脱硫性能を維持することができる排ガ
スの処理方法を提供することにある。Recently, in the above-mentioned dry desulfurization apparatus, a phenomenon in which the desulfurization rate changes when the type of fuel coal of the boiler is changed has been observed. This phenomenon occurs when unburned carbon containing a large amount of unburned carbon adheres to the desulfurizing agent of the desulfurizing absorption tower 4 or when a desulfurizing agent is manufactured using coal ash containing a large amount of unburned carbon. Although it has been clarified that this is the cause, in the above-mentioned conventional technology, dust from exhaust gas due to the type of fuel coal supplied to the boiler and unburned carbon in EP (Electric Precipitator) ash reduce the performance of the desulfurizing agent. No consideration was given to its effect, and it was not possible to prevent a reduction in the desulfurization rate in the absorption tower due to dust and unburned carbon in EP ash. The object of the present invention is to solve the above-mentioned problems of the prior art, and it is possible to maintain high desulfurization performance even when unburned carbon in exhaust gas is mixed or adhered to a desulfurization agent without being affected by boiler combustion conditions. An object of the present invention is to provide a method for treating exhaust gas.
【０００８】[0008]
【課題を解決するための手段】本発明者らは、上記課題
について、鋭意検討した結果、脱硫装置入口および出口
のＳＯ2 濃度を計測して脱硝率が一定となるように、ま
たは脱硫装置入口の一酸化窒素（ＮＯ）とＳＯ2 の濃度
比（ＮＯ／ＳＯ2 ）が所定値以上に維持するように、脱
硝装置に注入するアンモニア量を制御し、脱硫装置入口
のＮＯ濃度を適切にすることによって排ガス成分、特に
未燃カーボン等による脱硫率の低下が未然に防止され、
高性能の脱硝・脱硫が可能になることを見いだし、本発
明に到達したものである。すなわち、上記課題を達成す
るために本願で特許請求される発明はつぎの通りであ
る。Means for Solving the Problems As a result of intensive studies on the above-mentioned problems, the present inventors have measured the SO 2 concentration at the inlet and outlet of the desulfurization apparatus so that the denitration rate becomes constant, or at the inlet of the desulfurization apparatus. as nitric oxide (NO) and sO 2 concentration ratio (NO / sO 2) is maintained above a predetermined value, by controlling the amount of ammonia injected in the denitration apparatus, to properly NO concentration desulfurizer inlet This prevents a decrease in desulfurization rate due to exhaust gas components, especially unburned carbon, etc.,
The inventors have found that high-performance denitration / desulfurization is possible, and have reached the present invention. That is, the invention claimed in the present application to achieve the above object is as follows.
【０００９】（１）排ガスにアンモニアを注入して該排
ガス中の窒素酸化物を除去した後、該排ガスを石灰、石
膏および石炭灰を含む水和硬化体を脱硫剤として使用す
る脱硫装置に供給して排ガス中の硫黄酸化物を除去する
排ガスの処理方法において、前記脱硫装置の入口および
出口の排ガス中の二酸化硫黄濃度を測定し、これらの値
から算出される脱硫率が一定となるように前記排ガスに
注入するアンモニア量を制御することを特徴とする排ガ
スの処理方法。 （２）排ガスにアンモニアを注入して該排ガス中の窒素
酸化物を除去した後、該排ガスを石灰、石膏および石炭
灰を含む水和硬化体を脱硫剤とする脱硫装置に供給して
排ガス中の硫黄酸化物を除去する排ガスの処理方法にお
いて、前記脱硫装置入口の排ガス中の二酸化硫黄濃度と
一酸化窒素濃度を測定し、これらの濃度比（一酸化窒素
／二酸化硫黄）が０．２以上となるように前記排ガスに
注入するアンモニア量を制御することを特徴とする排ガ
スの処理方法。 （３）前記濃度比（一酸化窒素／二酸化硫黄）を前記脱
硫剤中の未燃カーボン量に応じて設定することを特徴と
する（２）に記載の排ガスの処理方法。(1) After injecting ammonia into the exhaust gas to remove nitrogen oxides in the exhaust gas, the exhaust gas is supplied to a desulfurization apparatus using a hydrated cured product containing lime, gypsum and coal ash as a desulfurizing agent. In the method of treating exhaust gas to remove sulfur oxides in the exhaust gas, the sulfur dioxide concentration in the exhaust gas at the inlet and the outlet of the desulfurization device is measured, and the desulfurization rate calculated from these values is kept constant. A method for treating exhaust gas, comprising controlling an amount of ammonia injected into the exhaust gas. (2) After injecting ammonia into the exhaust gas to remove nitrogen oxides in the exhaust gas, the exhaust gas is supplied to a desulfurization apparatus using a hydrated cured product containing lime, gypsum and coal ash as a desulfurizing agent, In the method for treating exhaust gas for removing sulfur oxides, the concentration of sulfur dioxide and the concentration of nitric oxide in the exhaust gas at the inlet of the desulfurizer are measured, and the concentration ratio (nitrogen monoxide / sulfur dioxide) is 0.2 or more. Controlling the amount of ammonia injected into the exhaust gas such that (3) The exhaust gas treatment method according to (2), wherein the concentration ratio (nitrogen monoxide / sulfur dioxide) is set according to the amount of unburned carbon in the desulfurizing agent.
【００１０】[0010]
【作用】石炭灰を脱硫剤として用いた場合の脱硫プロセ
スにおける脱硫反応は、主として次式（１）〜（４）の
反応式によって進む。なお、式中の（ａｄ）は脱硫剤に
吸着されている状態を示す。 ＮＯ→ＮＯ（ａｄ） （１） ＮＯ（ａｄ）＋Ｏ2 →２ＮＯ2 （ａｄ） （２） ＳＯ2 ＋Ｈ2 Ｏ＋ＮＯ2 （ａｄ）→Ｈ2 ＳＯ4 ＋ＮＯ （３） Ｃａ（ＯＨ）2 ＋Ｈ2 ＳＯ4→ＣａＳＯ4 ＋Ｈ2 Ｏ （４）The desulfurization reaction in the desulfurization process using coal ash as a desulfurizing agent mainly proceeds according to the following equations (1) to (4). In addition, (ad) in the formula indicates a state of being adsorbed by the desulfurizing agent. NO → NO (ad) (1) NO (ad) + O 2 → 2NO 2 (ad) (2) SO 2 + H 2 O + NO 2 (ad) → H 2 SO 4 + NO (3) Ca (OH) 2 + H 2 SO 4 → CaSO 4 + H 2 O (4)
【００１１】脱硝装置で処理された排ガスは脱硫装置に
供給されるが、ここでは、まず脱硫剤の表面に排ガス中
のＮＯが吸着され（式（１））、酸化されてＮＯ2 （ａ
ｄ）を生成する（式（２））。次に排ガス中のＳＯ2 が
脱硫剤の表面に吸着され、上記で生成したＮＯ2 （ａ
ｄ）によってＨ2 ＳＯ4 に酸化される（式（３））。生
じたＨ2 ＳＯ4 は脱硫剤中のアルカリ成分（ここではＣ
ａ（ＯＨ）2 ）と反応してＣａＳＯ4 となり固定化され
る（式（４））。また脱硫剤中へのＮＯｘの固定化（Ｃ
ａ（ＮＯｘ）2 の生成）反応はＳＯ2 共存下で促進され
る。本発明者らによる実験の結果、脱硫剤として石炭灰
を使用した場合、脱硫剤への未燃カーボンの付着量また
は含有量が増加するほど、脱硫剤表面に付着したＮＯの
ＮＯ2 への酸化反応が低下することがわかった。このた
め、式（３）におけるＳＯ2 の酸化に必要なＮＯ2 量が
不足し、脱硫性能を維持する活性点に達せず脱硫性能が
低下することになる。The exhaust gas treated by the denitrification device is supplied to the desulfurization device. Here, NO in the exhaust gas is first adsorbed on the surface of the desulfurizing agent (formula (1)), oxidized and NO 2 (a
d) is generated (Equation (2)). Next, SO 2 in the exhaust gas is adsorbed on the surface of the desulfurizing agent, and the NO 2 (a
It is oxidized to H 2 SO 4 by d) (formula (3)). The resulting H 2 SO 4 is an alkali component in the desulfurizing agent (here, C 2
a (OH) 2 ) to become CaSO 4 and be immobilized (formula (4)). Further, immobilization of NOx in the desulfurizing agent (C
a (NOx) 2 production) reaction is promoted in the presence of SO 2 . As a result of experiments by the present inventors, when coal ash was used as a desulfurizing agent, the oxidation of NO adhering to the surface of the desulfurizing agent to NO 2 increased as the amount or content of unburned carbon attached to the desulfurizing agent increased. The reaction was found to decrease. For this reason, the amount of NO 2 necessary for the oxidation of SO 2 in the formula (3) is insufficient, and the active point for maintaining the desulfurization performance is not reached, so that the desulfurization performance is reduced.
【００１２】一方、上記脱硫反応式からも推察されるよ
うに、脱硫装置に供給する排ガス中のＮＯ濃度が高けれ
ば、脱硫剤に未燃カーボンが付着または含有している場
合でも、脱硫剤へのＮＯの吸着とその酸化を促進するこ
とが可能である。また、脱硫装置入口の排ガス中のＮＯ
濃度の調整は、脱硫装置前流に設置された脱硝装置への
アンモニアの注入量を制御することにより可能である。
さらに脱硫装置の入口と出口のＳＯ2 濃度から算出され
る脱硫率（Ｃａ利用率）には排ガス中のＳＯ2濃度とＮ
Ｏ濃度が関係しているため、脱硫装置入口における排ガ
ス中のＳＯ2 濃度とＮＯ濃度の比を制御することにより
脱硫率を一定に維持することが可能となる。従って、脱
硫装置入口および出口のＳＯ2 濃度から算出される脱硝
率が一定となるように、または脱硫装置入口のＮＯとＳ
Ｏ2 の濃度比（ＮＯ／ＳＯ2 ）を所定値以上に維持する
ように、脱硝装置に注入するアンモニア量を制御し、脱
硫装置入口の排ガス中のＮＯ濃度を、脱硫剤に付着また
は含有する未燃カーボン量に応じた適切な濃度とするこ
とによって排ガス成分、特に未燃カーボン等による脱硫
率の低下が未然に防止され、高性能の脱硝・脱硫が可能
になる。On the other hand, as can be inferred from the above desulfurization reaction formula, if the NO concentration in the exhaust gas supplied to the desulfurization unit is high, even if unburned carbon is adhered to or contained in the desulfurization agent, the desulfurization agent is not used. It is possible to promote the adsorption of NO and its oxidation. In addition, NO in exhaust gas at the desulfurization unit inlet
The concentration can be adjusted by controlling the injection amount of ammonia into the denitration device installed upstream of the desulfurization device.
Further, the desulfurization rate (Ca utilization rate) calculated from the SO 2 concentrations at the inlet and outlet of the desulfurization device includes the SO 2 concentration in the exhaust gas and the N 2
Since the O concentration is involved, the desulfurization rate can be kept constant by controlling the ratio of the SO 2 concentration and the NO concentration in the exhaust gas at the inlet of the desulfurization device. Therefore, the denitration rate calculated from the SO 2 concentration at the inlet and outlet of the desulfurization device is kept constant, or NO and S
The amount of ammonia injected into the denitration device is controlled so that the O 2 concentration ratio (NO / SO 2 ) is maintained at or above a predetermined value, and the NO concentration in the exhaust gas at the inlet of the desulfurization device is attached to or contained in the desulfurizing agent. By adjusting the concentration to an appropriate value according to the amount of unburned carbon, a decrease in the desulfurization rate due to exhaust gas components, particularly unburned carbon, is prevented, and high-performance denitration / desulfurization becomes possible.
【００１３】[0013]
【発明の実施の形態】以下、本発明を図面により詳しく
説明するが、本発明はこれらに限定されるものではな
い。図１は、本発明に用いられる基本な排ガス処理装置
の系統図である。図１において、図２と異なる点は、排
ガスライン１１に排ガス中のＮＯ濃度を測定するＮＯ分
析計１３を設け、該ＮＯ分析計１３およびＳＯ2 分析計
７で測定された排ガス中のＮＯ濃度とＳＯ2 濃度から脱
硝装置２に注入するアンモニア量を算出するアンモニア
注入制御装置１４と、該アンモニア注入制御装置１４の
指示に従って脱硝装置２に注入するアンモニア量を制御
する自動制御バルブ１５を設けた点である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto. FIG. 1 is a system diagram of a basic exhaust gas treatment apparatus used in the present invention. 1 differs from FIG. 2 in that an NO analyzer 13 for measuring NO concentration in exhaust gas is provided in an exhaust gas line 11, and NO concentration in exhaust gas measured by the NO analyzer 13 and the SO 2 analyzer 7. An ammonia injection control device 14 for calculating the amount of ammonia to be injected into the denitration device 2 from the concentration of SO 2 and the SO 2 concentration, and an automatic control valve 15 for controlling the amount of ammonia to be injected into the denitration device 2 according to the instruction of the ammonia injection control device 14. Is a point.
【００１４】上記装置では、脱硫装置前流の排ガスライ
ン１１に設置されたＮＯ分析計１３とＳＯ2 分析計７に
より排ガス中のＮＯ濃度とＳＯ2 濃度が測定され、その
信号がアンモニア注入制御装置１４に入力され、ここで
脱硫吸収塔に供給される排ガスのＮＯ／ＳＯ2 濃度比が
算出され、さらに予め設定された未燃カーボン量の影響
を受けないＮＯ／ＳＯ2 濃度比を維持するのに必要なア
ンモニア量が算出される。算出されたアンモニア量の信
号が自動制御バルブ１５に入力され、適正な量のアンモ
ニアがアンモニア注入ライン１６から脱硝装置２に供給
される。In the above-described apparatus, the NO concentration and the SO 2 concentration in the exhaust gas are measured by the NO analyzer 13 and the SO 2 analyzer 7 installed in the exhaust gas line 11 upstream of the desulfurization device, and the signals are sent to the ammonia injection control device. Then, the NO / SO 2 concentration ratio of the exhaust gas supplied to the desulfurization absorption tower is calculated, and the NO / SO 2 concentration ratio not affected by the unburned carbon amount set in advance is maintained. The required amount of ammonia is calculated. A signal of the calculated amount of ammonia is input to the automatic control valve 15, and an appropriate amount of ammonia is supplied to the denitration device 2 from the ammonia injection line 16.
【００１５】実施例１ 実機脱硫剤製造装置により未燃カーボン量の異なる石炭
灰を用いた脱硫剤Ａ（未燃カーボン量：４％）および脱
硫剤Ｂ（未燃カーボン量：８％）を製造し、これらの脱
硫性能の評価を行った。脱硫性能の評価は、排ガス中の
ＳＯ2 濃度を５００ppm 一定とし、ＮＯ濃度は、１００
ppm （ＮＯ／ＳＯ2 比：０．２）の場合と、６０ppm
（〃：０．１２）の場合で行った。その結果を図３に示
したが、排ガス中のＮＯ／ＳＯ2 比が０．２の場合に
は、脱硝率中の未燃カーボン量が変化しても、Ｃａ利用
率（脱硫率）に大きな差は生じないが、ＮＯ／ＳＯ2 比
が０．１２の場合には、未燃カーボン量が多い脱硫剤Ｂ
の性能が大きく低下した。以上の結果から、脱硫剤中の
未燃カーボン量が多い場合には、排ガス中のＮＯ／ＳＯ
2 比が脱硫性能に影響を及ぼすこと、およびＮＯ／ＳＯ
2 比が０．２以上であれば未燃カーボン量に影響され
ず、脱硫率の低下を防止できることがわかる。Example 1 A desulfurizing agent A (unburned carbon amount: 4%) and a desulfurizing agent B (unburned carbon amount: 8%) using coal ash having different unburned carbon amounts were manufactured by an actual desulfurizing agent manufacturing apparatus. Then, their desulfurization performance was evaluated. The desulfurization performance was evaluated with the SO 2 concentration in the exhaust gas kept constant at 500 ppm and the NO concentration
ppm (NO / SO 2 ratio: 0.2) and 60 ppm
(〃: 0.12). The results are shown in FIG. 3. When the NO / SO 2 ratio in the exhaust gas is 0.2, the Ca utilization (desulfurization rate) is large even if the amount of unburned carbon in the denitration rate changes. Although there is no difference, when the NO / SO 2 ratio is 0.12, the desulfurizing agent B having a large unburned carbon content
Performance was greatly reduced. From the above results, when the amount of unburned carbon in the desulfurizing agent is large, the NO / SO
That the 2 ratio affects the desulfurization performance, and NO / SO
It can be seen that if the 2 ratio is 0.2 or more, the amount of unburned carbon is not affected, and a decrease in desulfurization rate can be prevented.
【００１６】実施例２ 未燃カーボンを２２％含有する石炭灰を８００℃で焼成
処理した後、もとの灰に対する焼成灰の配合比率を１０
０〜０％の範囲で混合灰を調製し、未燃カーボン含有量
の異なる５種類の脱硫剤を下記する方法で製造した。す
なわち、脱硫剤は、石炭灰３０重量％、消石灰３５重量
％および使用済脱硫剤３５重量％（ＣａＳＯ4 換算１６
重量％）からなる原料混合物に、水３６重量％（乾粉に
対する添加量）を添加して５分間混練し、混練物を押出
し成形して円柱状の成形品を得た。成形物は室温で風乾
した後、１００℃に保持した飽和水蒸気中で１０時間養
生し、次に加熱乾燥して脱水して製造した。Example 2 Coal ash containing 22% of unburned carbon was calcined at 800 ° C., and the mixture ratio of calcined ash to original ash was 10%.
Mixed ash was prepared in the range of 0 to 0%, and five types of desulfurizing agents having different unburned carbon contents were produced by the following method. That is, the desulfurizing agent is composed of 30% by weight of coal ash, 35% by weight of slaked lime, and 35% by weight of a used desulfurizing agent (16% in terms of CaSO 4).
36% by weight of water (the amount added to the dry powder) was added to the raw material mixture consisting of 100% by weight and kneaded for 5 minutes, and the kneaded product was extruded to obtain a cylindrical molded product. The molded product was air-dried at room temperature, cured for 10 hours in saturated steam maintained at 100 ° C., and then dried by heating and dewatering.
【００１７】各脱硫剤の性能は、排ガス中のＳＯ2 濃度
を５００ppm （一定）とし、ＮＯ濃度をそれぞれ１００
ppm （ＮＯ／ＳＯ2 比：０．２）、８０ppm （ＮＯ／Ｓ
Ｏ2比：０．１６）、６０ppm （ＮＯ／ＳＯ2 比：０．
１２）および４０ppm （ＮＯ／ＳＯ2 比：０．０８）と
し、それぞれの排ガスについて評価した。なお、排ガス
中には、ＳＯ2 およびＮＯ以外に、Ｏ2 （６％）、ＣＯ
2 （１２％）、Ｈ2 Ｏ（１０％）およびＮ2 を含有す
る。上記未燃カーボン量の異なる石炭灰を用いて得られ
た各脱硫剤を一定の条件で１００時間脱硫反応させた後
のＣａ利用率を調べ、その結果を図４に示した。図４か
ら、排ガス中のＮＯ／ＳＯ2 比が０．２では脱硫剤中の
未燃カーボン量に関係なく高い性能を示すことがわか
る。一方、ＮＯ／ＳＯ2 比が０．１６、０．１２、０．
０８と低下するに従い、未燃カーボン量が脱硫性能に及
ぼす影響が大きくなり、Ｃａ利用率が低下した。The performance of each desulfurizing agent is such that the SO 2 concentration in the exhaust gas is 500 ppm (constant) and the NO concentration is 100 ppm.
ppm (NO / SO 2 ratio: 0.2), 80 ppm (NO / S
O 2 ratio: 0.16), 60 ppm (NO / SO 2 ratio: 0.
12) and 40 ppm (NO / SO 2 ratio: 0.08), and each exhaust gas was evaluated. In the exhaust gas, in addition to SO 2 and NO, O 2 (6%), CO 2
2 (12%), containing H 2 O (10%) and N 2. Each desulfurizing agent obtained using the coal ash having a different amount of unburned carbon was subjected to a desulfurization reaction under constant conditions for 100 hours, and the Ca utilization was examined. The results are shown in FIG. FIG. 4 shows that when the NO / SO 2 ratio in the exhaust gas is 0.2, high performance is exhibited regardless of the amount of unburned carbon in the desulfurizing agent. On the other hand, when the NO / SO 2 ratio is 0.16, 0.12, 0.1.
08, the effect of the amount of unburned carbon on the desulfurization performance increased, and the Ca utilization decreased.
【００１８】以上の結果から、実機脱硫剤および実験室
製造脱硫剤ともに、脱硫装置に供給する排ガス中のＮＯ
／ＳＯ2 比が０．２以上であれば、脱硫性能は脱硫剤中
の未燃カーボン量に影響されないことが確認された。上
記結果は、脱硫剤に未燃カーボンが付着した場合におい
ても同様である。従って、脱硫装置入口の排ガス中のＮ
Ｏ／ＳＯ2 比を、未燃カーボン量の変動による脱硫率の
低下を防止できる値、すなわち０．２以上となるように
脱硝装置に供給するアンモニア量を制御することによ
り、脱硫装置入口のＮＯ濃度を適切な濃度に維持でき、
脱硫剤に未燃カーボン等の煤塵が付着し、または原料石
炭灰からの未燃カーボン含有量が増加した場合でも、脱
硫率を一定に維持することができる。前記ＮＯ／ＳＯ2
比は脱硫剤に付着または含有する未燃カーボン量に応じ
て適宜設定することが好ましい。上記実施例では、脱硫
装置の排ガス中のＮＯ／ＳＯ2 比に基づいて脱硝装置に
供給するアンモニア注入量を制御したが、脱硫装置の入
口と出口のＳＯ2 濃度を測定し、これらの値から算出さ
れる脱硫率が一定となるように脱硝装置に供給するアン
モニア注入量を制御し、脱硫装置前流の排ガス中のＮＯ
濃度を適切な濃度とすることによっても未燃カーボン量
の増加による脱硫率の低下を防止することができる。From the above results, both the actual desulfurizing agent and the desulfurizing agent manufactured in the laboratory show that NO
It was confirmed that when the / SO 2 ratio was 0.2 or more, the desulfurization performance was not affected by the amount of unburned carbon in the desulfurizing agent. The above result is the same even when unburned carbon adheres to the desulfurizing agent. Therefore, N in the exhaust gas at the desulfurization unit inlet
By controlling the amount of ammonia supplied to the denitrification device so that the O / SO 2 ratio becomes a value that can prevent the reduction of the desulfurization rate due to the change in the amount of unburned carbon, that is, 0.2 or more, the NO The concentration can be maintained at an appropriate concentration,
Even when dust such as unburned carbon adheres to the desulfurizing agent, or when the content of unburned carbon from the raw coal ash increases, the desulfurization rate can be kept constant. NO / SO 2
The ratio is preferably set as appropriate according to the amount of unburned carbon adhering to or contained in the desulfurizing agent. In the above embodiment, the injection amount of ammonia supplied to the denitration device was controlled based on the NO / SO 2 ratio in the exhaust gas of the desulfurization device. However, the SO 2 concentrations at the inlet and the outlet of the desulfurization device were measured, and from these values, The amount of injected ammonia supplied to the denitration device is controlled so that the calculated desulfurization rate is constant, and the NO in the exhaust gas upstream of the desulfurization device is controlled.
By setting the concentration to an appropriate concentration, a decrease in the desulfurization rate due to an increase in the amount of unburned carbon can be prevented.
【００１９】[0019]
【発明の効果】本発明の排ガスの処理方法によれば、石
灰、石膏および石炭灰を原料とする脱硫剤を用いた乾式
脱硫装置の吸収塔において、ボイラ燃料の石炭の種類、
燃焼条件の変動による脱硫率の低下を未然に防止するこ
とができる。According to the method for treating exhaust gas of the present invention, in the absorption tower of a dry desulfurization apparatus using a desulfurizing agent using lime, gypsum and coal ash as raw materials, the type of coal as boiler fuel,
It is possible to prevent a decrease in the desulfurization rate due to a change in combustion conditions.
【図１】本発明に用いられる基本的は排ガス処理装置の
系統図。FIG. 1 is a system diagram of a basic exhaust gas treatment apparatus used in the present invention.
【図２】従来技術による排ガス処理装置の系統図。FIG. 2 is a system diagram of an exhaust gas treatment apparatus according to the related art.
【図３】未燃カーボン含有量の異なる脱硫剤を用いたと
きの脱硫性能の比較図。FIG. 3 is a comparison diagram of desulfurization performance when desulfurizing agents having different unburned carbon contents are used.
【図４】石炭灰中未燃カーボン含有量と排ガス中のＮＯ
／ＳＯ2 比によるＣａ利用率との関係を示す図。FIG. 4 Unburned carbon content in coal ash and NO in exhaust gas
Diagram showing the relationship between the Ca utilization by / SO 2 ratio.
１…ボイラ、２…脱硝装置、３…空気予熱器、４…脱硫
吸収塔、５…電気集塵機、６…煙突、７…ＳＯ2 分析
計、８…ＳＯ2 分析計、９…脱硫剤製造装置、１０…使
用済脱硫剤、１１…排ガスライン、１２…脱硫剤供給ラ
イン、１３…ＮＯ分析計、１４…アンモニア注入制御装
置、１５…自動制御バルブ、１６…アンモニア注入ライ
ン。1 ... boiler, 2 ... denitrator, 3 ... air preheater, 4 ... desulfurization absorption tower, 5 ... electric precipitator, 6 ... chimney, 7 ... SO 2 analyzer, 8 ... SO 2 analyzer, 9 ... desulfurizing agent manufacturing apparatus Reference numeral 10: used desulfurizing agent, 11: exhaust gas line, 12: desulfurizing agent supply line, 13: NO analyzer, 14: ammonia injection control device, 15: automatic control valve, 16: ammonia injection line.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｂ０１Ｄ 53/86 Ｂ０１Ｄ 53/36 Ｄ 53/94 Ｆ２３Ｊ 15/00 Ｂ Ｂ０１Ｊ 20/06 Ｆ２３Ｊ 15/00 (72)発明者 吉川 博文 広島県呉市室町３番36号 バブコック日立 株式会社呉研究所内 (72)発明者 野坂 浩之 広島県呉市室町６番９号 バブコック日立 株式会社呉事業所内 Ｆターム(参考） 3K070 DA02 DA03 DA14 DA16 DA23 DA24 4D002 AA02 AA12 BA03 BA14 CA01 CA11 DA05 DA07 DA14 DA16 DA66 EA02 GA01 GA02 GA03 GB02 GB06 GB08 4D048 AA02 AA06 AB02 AC04 CC52 CD01 CD03 CD08 DA01 DA02 DA03 DA08 DA10 DA20 4G066 AA43B AA47B AA78B CA23 CA28 DA02 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) B01D 53/86 B01D 53/36 D 53/94 F23J 15/00 B B01J 20/06 F23J 15/00 (72 ) Inventor Hirofumi Yoshikawa 3-36 Muromachi, Kure-shi, Hiroshima Pref. Inside the Kure Research Laboratory, Babcock Hitachi Co., Ltd. (72) Inventor Hiroyuki Nosaka 6-9 Muromachi, Kure-shi, Hiroshima Pref. DA02 DA03 DA14 DA16 DA23 DA24 4D002 AA02 AA12 BA03 BA14 CA01 CA11 DA05 DA07 DA14 DA16 DA66 EA02 GA01 GA02 GA03 GB02 GB06 GB08 4D048 AA02 AA06 AB02 AC04 CC52 CD01 CD03 CD08 DA01 DA02 DA03 DA08 DA10 DA20 4G066 AA43BABAB23A47
Claims (3)
中の窒素酸化物を除去した後、該排ガスを石灰、石膏お
よび石炭灰を含む水和硬化体を脱硫剤として使用する脱
硫装置に供給して排ガス中の硫黄酸化物を除去する排ガ
スの処理方法において、前記脱硫装置の入口および出口
の排ガス中の二酸化硫黄濃度を測定し、これらの値から
算出される脱硫率が一定となるように前記排ガスに注入
するアンモニア量を制御することを特徴とする排ガスの
処理方法。1. After injecting ammonia into an exhaust gas to remove nitrogen oxides in the exhaust gas, the exhaust gas is supplied to a desulfurization apparatus using a hydrated cured product containing lime, gypsum and coal ash as a desulfurizing agent. In the method of treating exhaust gas to remove sulfur oxides in the exhaust gas, the sulfur dioxide concentration in the exhaust gas at the inlet and outlet of the desulfurization device is measured, and the desulfurization rate calculated from these values is kept constant. A method for treating exhaust gas, comprising controlling the amount of ammonia injected into the exhaust gas.
中の窒素酸化物を除去した後、該排ガスを石灰、石膏お
よび石炭灰を含む水和硬化体を脱硫剤として使用する脱
硫装置に供給して排ガス中の硫黄酸化物を除去する排ガ
スの処理方法において、前記脱硫装置入口の排ガス中の
二酸化硫黄濃度と一酸化窒素濃度を測定し、これらの濃
度比（一酸化窒素／二酸化硫黄）が０．２以上となるよ
うに前記排ガスに注入するアンモニア量を制御すること
を特徴とする排ガスの処理方法。2. After injecting ammonia into the exhaust gas to remove nitrogen oxides in the exhaust gas, the exhaust gas is supplied to a desulfurizer using a hydrated hardened product containing lime, gypsum and coal ash as a desulfurizing agent. In the exhaust gas treatment method for removing sulfur oxides in the exhaust gas, the concentration of sulfur dioxide and the concentration of nitric oxide in the exhaust gas at the inlet of the desulfurization unit are measured, and the concentration ratio (nitrogen monoxide / sulfur dioxide) is 0. A method for treating exhaust gas, wherein the amount of ammonia injected into the exhaust gas is controlled so as to be 2 or more.
を前記脱硫剤中の未燃カーボン量に応じて設定すること
を特徴とする請求項２に記載の排ガスの処理方法。3. The concentration ratio (nitrogen monoxide / sulfur dioxide).
3. The method for treating exhaust gas according to claim 2, wherein the value is set according to the amount of unburned carbon in the desulfurizing agent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001127169A JP2002320819A (en) | 2001-04-25 | 2001-04-25 | Method for treating waste gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001127169A JP2002320819A (en) | 2001-04-25 | 2001-04-25 | Method for treating waste gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002320819A true JP2002320819A (en) | 2002-11-05 |
Family
ID=18976085
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001127169A Pending JP2002320819A (en) | 2001-04-25 | 2001-04-25 | Method for treating waste gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2002320819A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010125377A (en) * | 2008-11-27 | 2010-06-10 | Babcock Hitachi Kk | Wet-type desulfurization apparatus |
| WO2017090262A1 (en) * | 2015-11-27 | 2017-06-01 | 株式会社セテック | Desulfurizing agent production method |
-
2001
- 2001-04-25 JP JP2001127169A patent/JP2002320819A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010125377A (en) * | 2008-11-27 | 2010-06-10 | Babcock Hitachi Kk | Wet-type desulfurization apparatus |
| WO2017090262A1 (en) * | 2015-11-27 | 2017-06-01 | 株式会社セテック | Desulfurizing agent production method |
| JP2017104855A (en) * | 2015-11-27 | 2017-06-15 | 株式会社 セテック | Production method for dry-type exhaust gas clarifier |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3272366B2 (en) | Exhaust gas treatment system | |
| CN105056749A (en) | System and method for removing nitric oxides and sulfur oxides in flue gas simultaneously | |
| CN101632897B (en) | Method for simultaneously removing sulfur oxides and nitric oxides in flue gas | |
| CN105688566A (en) | Desulfurization and denitrification device and method for sintering flue gas | |
| CN104759192A (en) | Low-cost coal-fired flue gas various pollutant ultralow emission system and low-cost coal-fired flue gas various pollutant ultralow emission method | |
| CN107551799B (en) | Dry-method cement kiln flue gas desulfurization and denitrification integrated method | |
| CN108554145A (en) | A kind of flue gas desulfurization denitration dust-removing takes off white device | |
| CN110787606B (en) | Denitration and demercuration integrated device and method for sintering flue gas circulating fluidized bed desulfurization | |
| CN104353356A (en) | Pelletizing flue gas cleaning and adsorbing tower of travelling grate machine | |
| CN109482049A (en) | A kind of coke oven flue gas dry desulfurization denitration purification integral process | |
| CN109647158B (en) | Flue gas desulfurization and denitrification system of circulating fluidized bed boiler and treatment method thereof | |
| CN113828148A (en) | Flue gas treatment system and flue gas treatment method for efficiently utilizing carbon monoxide | |
| CN207856647U (en) | A kind of gaseous oxidation collaboration absorption flue gas multiple pollutant purifier | |
| CN206463781U (en) | A kind of desulfuring and denitrifying apparatus of coke oven flue gas | |
| KR20080059958A (en) | Simultaneous flue gas desulfurization and denitrification with ozone and active coke | |
| CN204261560U (en) | A kind of belt type roasting machine pelletizing gas cleaning adsorption tower | |
| CN110585868A (en) | Preparation and application of dry-wet dual-purpose flue gas desulfurization and denitrification agent | |
| CN101161331A (en) | Method for processing low concentration unwanted waste gas using microwave-solid castoff | |
| JP2002320819A (en) | Method for treating waste gas | |
| CN212999279U (en) | Flue gas treatment system for efficiently utilizing carbon monoxide | |
| CN107830739A (en) | Sintering flue gas full-flow purification system and method thereof | |
| KR20220144993A (en) | Apparatus for treating gas from combustion installations | |
| CN113332839A (en) | Cement kiln flue gas desulfurization and denitrification coupling recycling system and method | |
| CN203525549U (en) | Equipment used for flue gas desulfurization and denitrification | |
| CN207493486U (en) | A kind of desulfurization of coke oven flue gas and de-dusting de-nitration integrated |