JPH08206459A - Denitration treatment of exhaust gas - Google Patents
Denitration treatment of exhaust gasInfo
- Publication number
- JPH08206459A JPH08206459A JP7020851A JP2085195A JPH08206459A JP H08206459 A JPH08206459 A JP H08206459A JP 7020851 A JP7020851 A JP 7020851A JP 2085195 A JP2085195 A JP 2085195A JP H08206459 A JPH08206459 A JP H08206459A
- Authority
- JP
- Japan
- Prior art keywords
- urea
- water
- exhaust gas
- urea water
- spray
- 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
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ガスタービンやディゼ
ルエンジン等の熱機関から排出される排ガスの脱硝処理
方法の改良に係り、尿素水を還元剤とする選択接触還元
触媒を用いた排ガス脱硝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 an improvement in a method for denitration of exhaust gas discharged from a heat engine such as a gas turbine or a diesel engine, and an exhaust gas denitration using a selective catalytic reduction catalyst using urea water as a reducing agent. It relates to a processing method.
【０００２】[0002]
【従来の技術】所謂コージエネレーションシステムは、
エネルギー政策や環境保護政策等の点から今後より一層
その活用が期待されている技術である。このコージエネ
レーションシステムの普及を図るためには、システムの
主駆動源であるディーゼルエンジンやガスタービンから
排出される排気ガス内のＮＯｘ濃度を、高能率で安全に
しかも低コストで規制値以下の値に低減し得る技術を必
要とする。排ガスによって大気汚染を生じたり、ＮＯｘ
除去費が嵩むようでは、コージエネレーションシステム
のメリットが失なわれてしまうからである。2. Description of the Related Art The so-called cogeneration system is
It is a technology that is expected to be further utilized from the viewpoint of energy policy and environmental protection policy. In order to popularize this cogeneration system, the NOx concentration in the exhaust gas discharged from the diesel engine or the gas turbine, which is the main drive source of the system, can be controlled with high efficiency, safely and at low cost, below the regulation value. It requires a technology that can reduce the value. Exhaust gas causes air pollution, NOx
If the removal cost increases, the merit of the cogeneration system will be lost.
【０００３】ところで、コージエネレーションシステム
の活用の初期段階に於いては、主としてディーゼルエン
ジン等の駆動源側の改良により排ガス内のＮＯｘの低減
が図られて来た。その後、駆動源側のみの努力ではＮＯ
ｘの低減に限界があるため、所謂アンモニヤを還元剤と
する選択接触還元触媒を用いた脱硝処理装置を設け、排
ガスを処理するようになって来た。By the way, in the early stage of utilization of the cogeneration system, NOx in exhaust gas has been reduced mainly by improving the drive source side such as a diesel engine. After that, the effort of the drive source side is NO
Since there is a limit to the reduction of x, it has come to treat exhaust gas by providing a denitration treatment device using a selective catalytic reduction catalyst using so-called ammonia as a reducing agent.
【０００４】しかし、還元剤として使用される液体アン
モニヤやアンモニヤ水は、毒性が強い上に取扱いが難か
しく、都市部の事務所ビル内や工場内に設置するコージ
エネレーションシステムでは、採用し難いと云う難点が
ある。そのため、安全で且つ取扱いの比較的容易な尿素
水を脱硝用の還元剤として利用する技術の開発が進めら
れ、実用に供されて来た。尿素水はアンモニヤやアンモ
ニヤ水に比較して取扱いが比較的簡単なうえ、安価で、
悪臭を発しないため、脱臭装置や排水処理装置が不要で
所要設置面積が少なくてよい等の様々な利点があるから
である。However, liquid ammonium and ammonium water used as a reducing agent are highly toxic and difficult to handle, and are difficult to adopt in a cogeneration system installed in office buildings or factories in urban areas. There is a difficulty to say. Therefore, the development of a technique of using urea water, which is safe and relatively easy to handle, as a reducing agent for denitration has been advanced and put to practical use. Urea water is relatively easy to handle and cheaper than ammonia and ammonia water.
This is because there are various advantages such as a deodorizing device and a wastewater treatment device are not required because a bad odor is not generated and a required installation area may be small.
【０００５】しかし乍ら、尿素水を還元剤とする選択接
触脱硝方法にも解決すべき多くの問題が残されている。
その中でも特に重要な問題は、尿素水を排ガス内へ噴出
するための尿素水噴霧ノズルの閉塞の問題である。即
ち、尿素水には、その濃度と使用温度域によってシアヌ
ル酸等の固形物を生じると云う特性があり、しかも、こ
のシアヌル酸等の析出固形物は、高温排ガス中に設置さ
れた尿素水噴霧ノズルの細孔部に多く起生する。その結
果、尿素水噴霧ノズルに閉塞等のトラブルが多発するこ
とになる。However, the selective catalytic denitration method using urea water as a reducing agent still has many problems to be solved.
Among them, a particularly important problem is the problem of clogging of the urea water spray nozzle for ejecting urea water into the exhaust gas. That is, urea water has a characteristic that solids such as cyanuric acid are produced depending on the concentration and temperature range of use, and the precipitated solids such as cyanuric acid are urea water sprays installed in high-temperature exhaust gas. It often occurs in the pores of the nozzle. As a result, troubles such as blockage frequently occur in the urea water spray nozzle.
【０００６】より具体的に説明すると、ガスタービンや
ディゼルエンジンからの排ガスのＮＯｘ濃度や排ガス温
度は、一般的に図５に示す如くエンジン出力と比例的に
増減する関係にある。また、排ガス内へ噴出する噴霧尿
素水の量は排ガス内のＮＯｘ濃度と一定の関係に保持さ
れており、例えばエンジン出力を検出し、これによって
噴霧尿素水量を制御したり（特開平３−１４１８１５
号）、或いは排ガス内のＮＯｘ濃度を検出し、当該検出
信号により噴霧尿素水量を制御するようにしている。More specifically, the NOx concentration of the exhaust gas from the gas turbine or the diesel engine and the exhaust gas temperature generally have a relationship of increasing or decreasing in proportion to the engine output as shown in FIG. Further, the amount of sprayed urea water ejected into the exhaust gas is held in a constant relationship with the NOx concentration in the exhaust gas. For example, the engine output is detected and the sprayed urea water amount is controlled by this (Japanese Patent Laid-Open No. 3-141815).
No.) or the NOx concentration in the exhaust gas is detected, and the amount of spray urea water is controlled by the detection signal.
【０００７】ところで、ディーゼルエンジン等が定常負
荷状態で運転され、従って尿素水噴霧ノズルへの噴霧尿
素水の供給量が所定量以上の場合には、流通する噴霧尿
素水によって尿素水噴霧ノズルの内表面が十分に冷却さ
れる。その結果、ノズルの温度が過度な水分蒸発を生ず
る高温度にまで上昇することは無い。しかし、エンジン
負荷が減少して排ガス内のＮＯｘ濃度が低下し、その結
果噴霧尿素水の流量が減少してくると、噴霧尿素水自体
によるノズル孔内表面の冷却効果が低減する。そうする
と、尿素水噴霧ノズルの内表面温度が過昇し、噴霧尿素
水内の水分が蒸発して、ノズル細孔部にシアヌル酸等の
析出が進行し、短時間内にノズル細孔部が閉塞すること
になる。By the way, when a diesel engine or the like is operated under a steady load condition and therefore the supply amount of the spray urea water to the urea water spray nozzle is more than a predetermined amount, the amount of the spray urea water flowing inside the urea water spray nozzle The surface is sufficiently cooled. As a result, the temperature of the nozzle does not rise to a high temperature which causes excessive moisture evaporation. However, when the engine load decreases and the NOx concentration in the exhaust gas decreases, and as a result, the flow rate of the spray urea water decreases, the cooling effect of the spray urea water itself on the inner surface of the nozzle hole decreases. Then, the inner surface temperature of the urea water spray nozzle rises excessively, the water content in the spray urea water evaporates, and the precipitation of cyanuric acid and the like progresses in the nozzle pores, closing the nozzle pores within a short time. Will be done.
【０００８】[0008]
【発明が解決しようとする課題】本発明は、従前の尿素
水を還元剤とする選択接触還元触媒を用いたガスタービ
ンやディーゼルエンジン等の熱機関の排ガスの脱硝処理
に於ける上述の如き問題、即ちディゼルエンジン等が軽
負荷になって噴霧尿素水量が減少すると、尿素水噴霧ノ
ズルの細孔内に固形物が析出し、これに起因する詰り事
故が発生し易いと云う問題を解決せんとするものであ
り、噴霧尿素水量を常に所定流量以上に保持すると共
に、噴霧尿素水内の尿素濃度を調整して排ガス内へ噴出
する尿素量を最適量とすることにより、前記ノズル細孔
の詰まりを有効に防止すると共に、過度な尿素の供給を
防止し、未反応アンモニヤによる二次公害の発生や脱硝
処理費の高騰を招来することの無いようにした排ガスの
脱硝処理方法を提供するものである。DISCLOSURE OF THE INVENTION The present invention has the above-mentioned problems in the denitrification treatment of the exhaust gas of a heat engine such as a gas turbine or a diesel engine using a selective catalytic reduction catalyst using urea water as a reducing agent. That is, when the diesel engine etc. becomes lightly loaded and the amount of sprayed urea water decreases, solid matter is deposited in the pores of the urea water spray nozzle, and the problem that clogging accidents due to this tend to occur is solved. That is, the amount of sprayed urea water is always maintained at or above a predetermined flow rate, and the amount of urea sprayed into the exhaust gas is adjusted to an optimum amount by adjusting the urea concentration in the sprayed urea water, thereby clogging the nozzle pores. To prevent excessive supply of urea and to prevent the generation of secondary pollution due to unreacted ammonia and the rise in denitration treatment costs, and to provide a denitration treatment method for exhaust gas. It is intended.
【０００９】[0009]
【課題を解決するための手段】本発明は、尿素水を還元
剤とする選択接触還元触媒を用いた排ガスの脱硝処理方
法に於いて、尿素水原液と水とを混合して排ガス内へ噴
霧する噴霧尿素水を形成すると共に、排ガス内のＮＯｘ
濃度に応じてコントローラにより尿素水原液と水の混合
比を調整し、前記噴霧尿素水の流量を常に設定値以上の
流量に保持すると共に、噴霧尿素水内の尿素濃度を、排
ガス内のＮＯｘ濃度を設定値に低減するのに必要な尿素
量が供給される値に保持することを発明の基本構成とす
るものである。The present invention relates to a method for denitration of exhaust gas using a selective catalytic reduction catalyst using urea water as a reducing agent, wherein a urea water stock solution and water are mixed and sprayed into the exhaust gas. Atomized urea water that forms
The controller adjusts the mixing ratio of the urea aqueous solution and the water according to the concentration to keep the flow rate of the sprayed urea water at a flow rate higher than a set value at the same time, and also changes the urea concentration in the spray urea solution to the NOx concentration in the exhaust gas. The basic configuration of the invention is to maintain the urea amount required to reduce the amount of urea to a set value.
【００１０】[0010]
【作用】尿素水原液タンク１２からの尿素水原液Ｎ1 と
水タンク１４からの水Ｗとが混合弁１６によって混合さ
れ、噴霧尿素水Ｎが形成されると共に、尿素水噴霧ノズ
ル６を通して噴霧尿素水Ｎが排ガスＧ内へ噴出される。
また、噴出された噴霧尿素水Ｎは還元剤として作用し、
選択接触還元触媒の作用により排ガス内のＮＯｘをＮ2
とＯ2 に分解除去する。エンジン等の出力が低下して排
ガス内のＮＯｘ濃度が下降してくると、コントローラ１
８を介して三方弁１６が作動され、水Ｗ内への尿素水原
液Ｎ1 の混合量を減少させると共に水Ｗの供給量が増加
される。これにより、排ガス内へ供給される尿素量はＮ
Ｏｘ濃度に対応して減少するが、尿素水噴霧ノズル６内
を流通する噴霧尿素水Ｎの量は所定値以上の流量に保持
される。その結果、尿素水噴霧ノズル６の内部が十分に
冷却されることになり、シアヌル酸等の固形物の析出が
防止される。The urea water stock solution N 1 from the urea water stock solution tank 12 and the water W from the water tank 14 are mixed by the mixing valve 16 to form the spray urea water N, and the spray urea solution is sprayed through the urea water spray nozzle 6. Water N is ejected into the exhaust gas G.
Further, the sprayed urea water N that has been ejected acts as a reducing agent,
NOx in the exhaust gas is converted into N 2 by the action of the selective catalytic reduction catalyst.
And decomposed into O 2 . When the output of the engine or the like decreases and the NOx concentration in the exhaust gas decreases, the controller 1
The three-way valve 16 is operated via 8 to decrease the amount of the urea aqueous solution N 1 mixed into the water W and increase the amount of the water W supplied. As a result, the amount of urea supplied into the exhaust gas is N
The amount of the sprayed urea water N flowing through the urea water spray nozzle 6 is maintained at a flow rate equal to or higher than a predetermined value, although the amount decreases in accordance with the Ox concentration. As a result, the inside of the urea water spray nozzle 6 is sufficiently cooled, and the precipitation of solid matter such as cyanuric acid is prevented.
【００１１】[0011]
【実施例】以下、図面に基づいて本発明の実施例を説明
する。図１は本発明の実施に使用する排ガス脱硝装置の
第１実施例を示すものであり、図に於いて１はディーゼ
ルエンジンやガスタービン等の熱機関、２は脱硝反応
器、３は排熱回収ボイラ、４は排ガスダクト、５は排気
筒、６は尿素水噴霧ノズル、７は尿素水・空気混合部、
８は尿素水供給管、９はコンプレッサ、１０は空気供給
管、１１はＮＯｘ計、１２は尿素水原液タンク、１３は
尿素水原液供給ポンプ、１４は軟水や純水等の水タン
ク、１５は水供給ポンプ、１６は混合弁、１７は出力検
出装置、１８はコントローラである。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of an exhaust gas denitration apparatus used for carrying out the present invention. In the figure, 1 is a heat engine such as a diesel engine or a gas turbine, 2 is a denitration reactor, and 3 is exhaust heat. Recovery boiler, 4 exhaust gas duct, 5 exhaust stack, 6 urea water spray nozzle, 7 urea water / air mixing section,
Reference numeral 8 is a urea water supply pipe, 9 is a compressor, 10 is an air supply pipe, 11 is a NOx meter, 12 is a urea water stock solution tank, 13 is a urea water stock solution supply pump, 14 is a water tank for soft water or pure water, and 15 is A water supply pump, 16 is a mixing valve, 17 is an output detection device, and 18 is a controller.
【００１２】図１を参照して、ディーゼルエンジン１か
らの排ガスＧは排ガスダクト４を通して導出され、高温
排ガス内へ所定量の還元剤である噴霧尿素水Ｎが噴霧混
合されたあと、排ガスＧは選択接触触媒を備えた脱硝反
応器２へ導入される。即ち、脱硝反応器２の上流側のダ
クト４内に尿素水・空気混合部７を有する尿素水噴霧ノ
ズル６が設けられており、尿素水供給管８を通して供給
された噴霧尿素水Ｎが、コンプレッサ９から空気供給管
１０を通して供給された圧縮空気Ａにより、ノズル６の
先端細孔より微細な霧状となって排ガスＧ内へ噴霧混合
される。Referring to FIG. 1, exhaust gas G from a diesel engine 1 is led out through an exhaust gas duct 4, and a predetermined amount of a spray urea water N which is a reducing agent is spray-mixed into the high temperature exhaust gas. It is introduced into the denitration reactor 2 equipped with a selective contact catalyst. That is, the urea water spray nozzle 6 having the urea water / air mixing portion 7 is provided in the duct 4 on the upstream side of the denitration reactor 2, and the spray urea water N supplied through the urea water supply pipe 8 is compressed by the compressor. The compressed air A supplied from 9 through the air supply pipe 10 forms a fine mist from the fine pores at the tip of the nozzle 6 and is spray-mixed into the exhaust gas G.
【００１３】前記噴霧された霧状尿素水Ｎは高温排ガス
Ｇによって瞬時に気化され、尿素は直ちにアンモニヤに
転換される。そして、脱硝反応器２内へ導入されたアン
モニヤを含む排ガスＧは、ここで所謂選択接触還元触媒
によって脱硝処理を受け、ＮＯｘが還元されてＮ2 とＯ
2 に分解することにより、排ガスＧ内から除去される。
脱硝反応器２で許容ＮＯｘ濃度にまでＮＯｘを低減され
た排ガスＧは、排熱回収ボイラで熱を回収されたあと、
排気筒５から大気中へ放出されて行く。The atomized urea water N thus sprayed is instantly vaporized by the high temperature exhaust gas G, and urea is immediately converted into ammonia. Then, the exhaust gas G containing the ammonia introduced into the denitration reactor 2 is subjected to denitration treatment by a so-called selective catalytic reduction catalyst, and NOx is reduced to N 2 and O 2.
By being decomposed into 2 , it is removed from the exhaust gas G.
The exhaust gas G whose NOx concentration has been reduced to the allowable NOx concentration in the denitration reactor 2 has its heat recovered by the exhaust heat recovery boiler,
It is released from the exhaust stack 5 into the atmosphere.
【００１４】尚、図２は本発明で使用する尿素水噴霧ノ
ズルの縦断面図であり、尿素水・空気混合部７に於いて
噴霧尿素水Ｎと圧縮空気Ａとが混合され、比較的長い筒
部７ａ内で十分に混合されたあと、噴霧尿素水Ｎは細孔
７ｂを通して霧化噴射されて行く。また、上記尿素水を
還元剤とする選択接触還元触媒法による排ガスの脱硝処
理は公知の技術であり、従って、脱硝反応器２等の詳細
な説明は省略する。FIG. 2 is a vertical sectional view of the urea water spray nozzle used in the present invention, in which the spray urea water N and the compressed air A are mixed in the urea water / air mixing portion 7 and are relatively long. After being sufficiently mixed in the tubular portion 7a, the atomized urea water N is atomized and injected through the pores 7b. Further, the denitrification treatment of the exhaust gas by the selective catalytic reduction catalyst method using the urea water as a reducing agent is a known technique, and therefore detailed description of the denitration reactor 2 and the like will be omitted.
【００１５】次に、本発明の要部を構成する噴霧尿素水
の供給系統について説明する。本発明に於いては、前記
尿素水供給管８を通して尿素水噴霧ノズル６へ供給する
噴霧尿素水Ｎを、尿素水原液タンク１２内に貯留した尿
素水原液Ｎ1 と水タンク１４内に貯留した軟水又は純水
等の水Ｗとを混合弁１６で混合することにより形成す
る。そして、エンジン出力検出装置１７からの検出信号
によりコントローラ１８を介して混合弁１６を制御し、
尿素水噴霧ノズル６へ供給する噴霧尿素水Ｎの尿素濃度
を調整すると共に、エンジン負荷の低いときでも、所定
流量の噴霧尿素水Ｎがノズル６へ流通するように、水Ｗ
の流量を増加する構成としている。Next, the supply system of sprayed urea water, which constitutes the essential part of the present invention, will be described. In the present invention, the sprayed urea water N supplied to the urea water spray nozzle 6 through the urea water supply pipe 8 is stored in the urea water stock solution N 1 stored in the urea water stock solution tank 12 and the water tank 14. It is formed by mixing water W such as soft water or pure water with the mixing valve 16. Then, the mixing valve 16 is controlled via the controller 18 by the detection signal from the engine output detection device 17,
The urea concentration of the spray urea water N supplied to the urea water spray nozzle 6 is adjusted, and the water W is supplied so that a predetermined flow rate of the spray urea water N flows to the nozzle 6 even when the engine load is low.
The flow rate of is increased.
【００１６】即ち、前記尿素水原液タンク１２にはタン
クローリから比較的高尿素濃度の尿素水原液Ｎ1 が貯留
されている。また、前記水タンク１４には軟水器（図示
省略）を通して軟水が充填されている。尚、軟水に替え
て純水を用いることも可能である。更に、前記尿素水原
液Ｎ1 は尿素水原液供給ポンプ１３により、また前記水
Ｗは水供給ポンプ１５により夫々混合弁１６へ送られ、
ここで両者が混合される。That is, in the urea solution stock solution tank 12, a urea solution solution N 1 having a relatively high urea concentration is stored from a tank truck. The water tank 14 is filled with soft water through a water softener (not shown). Pure water can be used instead of soft water. Furthermore, the urea water stock solution N 1 is sent to the urea water stock solution supply pump 13 and the water W is sent to the mixing valve 16 by the water supply pump 15, respectively.
Both are mixed here.
【００１７】一方、ディーゼルエンジン等の熱機関１の
出力は出力検出装置１７により連続的に検出されてお
り、検出信号はコントローラ１８へ入力されている。而
して、ディーゼルエンジンの出力と排ガスＧ内の排出Ｎ
Ｏｘ濃度とは図５に示す如くほぼ比例関係にある。従っ
て、排出ＮＯｘの還元分解に必要とする還元剤（噴霧尿
素水Ｎ）の量はエンジン出力即ち排出ＮＯｘ濃度に比例
することになる。いま、ここで、還元剤である噴霧尿素
水Ｎの供給流量を一定値とした場合には、図３に示す如
く還元剤である噴霧尿素水Ｎの尿素濃度がエンジン出力
（即ち排ガスのＮＯｘ濃度）に比例することになる。On the other hand, the output of the heat engine 1 such as a diesel engine is continuously detected by the output detection device 17, and the detection signal is input to the controller 18. Thus, the output of the diesel engine and the emission N in the exhaust gas G
The Ox concentration is in a substantially proportional relationship as shown in FIG. Therefore, the amount of the reducing agent (spray urea water N) required for the reductive decomposition of exhausted NOx is proportional to the engine output, that is, the exhausted NOx concentration. Now, when the supply flow rate of the spray urea water N that is the reducing agent is set to a constant value, the urea concentration of the spray urea water N that is the reducing agent is the engine output (that is, the NOx concentration of the exhaust gas as shown in FIG. 3). ) Will be proportional to.
【００１８】本発明に於いては、熱機関（ディーゼルエ
ンジン）１の出力が極めて軽負荷の場合であっても、尿
素水噴霧ノズル６へ設定流量Ｖの噴霧尿素水Ｎを供給す
るように、コントローラ１８を介して混合弁１６が制御
され、低濃度（尿素水原液Ｎ 1 ／水Ｗが小）の噴霧尿素
水Ｎが流量Ｖでもって噴霧ノズル６へ供給される。ま
た、逆にディーゼルエンジン１の出力が１００％前後に
なると、高尿素濃度（尿素水原液Ｎ1 ／軟水Ｗが大）の
噴霧尿素水Ｎが流量Ｖ若しくはこれより大きい流量でも
って供給される。In the present invention, the heat engine (diesel engine
Urine, even if the output of
A spray urea water N having a set flow rate V is supplied to the plain water spray nozzle 6.
Control the mixing valve 16 via the controller 18
Low concentration (urea water stock solution N 1/ Small amount of water W)
Water N is supplied to the spray nozzle 6 with a flow rate V. Well
On the contrary, the output of the diesel engine 1 is around 100%.
When it comes to high urea concentration (urea water stock solution N1/ Large amount of soft water W)
Even if the sprayed urea water N has a flow rate V or a flow rate higher than this
Will be supplied.
【００１９】尚、排ガスＧ内へ供給する還元剤（噴霧尿
素水Ｎ）は、排ガス内ＮＯｘ濃度を規定値以下に削減し
得る量だけでよく、通常は除去すべきＮＯｘ量の約１／
２当量に相当する尿素量が供給される。The reducing agent (spray urea water N) to be supplied into the exhaust gas G is only required to reduce the NOx concentration in the exhaust gas to a specified value or less, and is usually about 1 / n of the NOx amount to be removed.
An amount of urea equivalent to 2 equivalents is supplied.
【００２０】また、ディーゼルエンジン１を停止する場
合には、先ずエンジンの出力信号が設定値以下（例えば
定格出力の１〜５％）になれば混合弁１６の尿素水原液
Ｎ1の入口側を閉鎖し、水Ｗのみを一定時間噴霧ノズル
６へ供給し、供給管８内に残留する噴霧尿素水Ｎを完全
に排出し、水Ｗと置換する。その後、エンジン１を完全
停止すると共に、尿素水原液供給ポンプ１３、水供給ポ
ンプ１５及びコンプレッサ９を停止させ、これによって
尿素水噴霧ノズル６の析出固形物による詰まりを防止す
る。Further, when the diesel engine 1 is stopped, first, if the output signal of the engine becomes equal to or lower than a set value (for example, 1 to 5% of the rated output), the inlet side of the urea solution undiluted solution N 1 of the mixing valve 16 is set. It is closed and only the water W is supplied to the spray nozzle 6 for a certain period of time, and the spray urea water N remaining in the supply pipe 8 is completely discharged and replaced with the water W. After that, the engine 1 is completely stopped, and the urea water stock solution supply pump 13, the water supply pump 15, and the compressor 9 are stopped to prevent the urea water spray nozzle 6 from being clogged with the deposited solid matter.
【００２１】図４は本発明の実施に使用する排ガスの脱
硝装置の第２実施例を示すものである。当該第２実施例
に於いては、前記第１実施例が混合弁１６の開度を調整
し、水Ｗと尿素水原液Ｎ1 との混合比を変えることによ
りノズル６へ供給する噴霧尿素水Ｎの尿素濃度を制御し
ているのに対して、尿素水原液供給ポンプ１３及び水供
給ポンプ１５の吐出量をコントローラ１８により制御
し、ノズル６へ供給する噴霧尿素水Ｎの濃度及び流量を
夫々調整するようにしている。FIG. 4 shows a second embodiment of the exhaust gas denitration apparatus used for carrying out the present invention. In the second embodiment, the spray urea water which is supplied to the nozzle 6 by adjusting the opening of the mixing valve 16 and changing the mixing ratio of the water W and the urea water stock solution N 1 in the second embodiment. While the urea concentration of N is controlled, the discharge amounts of the urea water stock solution supply pump 13 and the water supply pump 15 are controlled by the controller 18, and the concentration and flow rate of the spray urea water N supplied to the nozzle 6 are controlled. I am trying to adjust it.
【００２２】即ち、図４に於いて、１９、２０はインバ
ータ、２１は水供給ポンプ用モータ、２２は尿素水原液
供給ポンプ用モータ、２３、２４は電磁弁であり、エン
ジン出力検出装置１７からの検出信号をコントローラ１
８へ入力し、コントローラ１８によりインバータ１９、
２０を介して両ポンプ２１、２２の回転数制御を行な
う。これにより、両電磁弁２３、２４に流通する水Ｗと
尿素水原液Ｎ1 の流量が調整され、尿素水供給管８内を
流通する噴霧尿素水Ｎの尿素濃度が調整される。That is, in FIG. 4, 19 and 20 are inverters, 21 is a water supply pump motor, 22 is a urea water stock solution supply pump motor, and 23 and 24 are solenoid valves. Detection signal of controller 1
8 and the controller 18 drives the inverter 19,
The rotation speed of both pumps 21 and 22 is controlled via 20. As a result, the flow rates of the water W and the urea water stock solution N 1 flowing through the solenoid valves 23, 24 are adjusted, and the urea concentration of the spray urea water N flowing through the urea water supply pipe 8 is adjusted.
【００２３】尚、前記両ポンプ２１、２２の回転数制御
は、ノズル６へ供給する噴霧尿素水Ｎの流量が常に設定
値以上となり、且つ噴霧尿素水Ｎの尿素濃度が、ＮＯｘ
低減に必要とする尿素量を排ガスＧ内へ供給できる濃度
値となるよう調整されることは、勿論である。In the rotation speed control of both the pumps 21 and 22, the flow rate of the spray urea water N supplied to the nozzle 6 is always a set value or more, and the urea concentration of the spray urea water N is NOx.
It is needless to say that the amount of urea required for the reduction is adjusted to a concentration value capable of supplying it into the exhaust gas G.
【００２４】また、前記各実施例では、エンジン出力検
出装置１７からの信号によりコントローラ１８を介し
て、ノズル６へ供給する噴霧尿素水の尿素濃度を調整す
るようにしているが、ＮＯｘ計１１の検出信号等によっ
て前記噴霧尿素水の流量や尿素濃度を調整するようにし
てもよい。In each of the above-mentioned embodiments, the urea concentration of the sprayed urea water supplied to the nozzle 6 is adjusted via the controller 18 by the signal from the engine output detecting device 17. The flow rate and the urea concentration of the sprayed urea water may be adjusted by the detection signal or the like.
【００２５】[0025]
【発明の効果】本発明では、尿素水噴霧ノズル６へ供給
する噴霧尿素水Ｎの流量を常に設定値以上に保持すると
共に、噴霧尿素水Ｎの尿素濃度を調整して必要量の尿素
が排ガスＧ内へ常に供給されるようにしているため、デ
ィーゼルエンジン１等が軽負荷になって排ガスＧ内のＮ
Ｏｘ濃度が低下した場合に於いても、尿素水噴霧ノズル
６には十分な噴霧尿素水Ｎが流通する。その結果、従前
のこの種脱硝システムのような析出硬化物によるノズル
細孔の詰まり等のトラブルが皆無となり、尿素水を還元
剤とする選択接触還元触媒法による排ガスの脱硝処理を
高能率で、しかも安全に行なえる。また、本発明では、
排ガス内のＮＯｘ濃度を所定値までに引き下げるのに必
要な尿素量が供給されるように、噴霧尿素水Ｎの尿素濃
度を自動調整するようにしているため、尿素供給の過多
による未反応アンモニヤの排出等の問題を生ずる恐れも
全く無い。更に、本発明では、尿素水噴霧を停止する際
に、尿素水噴霧ノズル６内の噴霧尿素水Ｎを水Ｗで置換
する構成としているため、噴霧尿素水Ｎの噴霧停止後に
排ガスＧ等の残熱によりノズル６内の噴霧尿素水Ｎが沸
騰し、固形物が析出してノズル細孔を閉塞するようなこ
とが皆無となる。本発明は上述の通り、優れた実用的効
果を奏するものである。According to the present invention, the flow rate of the spray urea water N supplied to the urea water spray nozzle 6 is always maintained at the set value or more, and the urea concentration of the spray urea water N is adjusted to reduce the required amount of urea to the exhaust gas. Since it is always supplied to the inside of G, the diesel engine 1 etc. becomes a light load and the N in the exhaust gas G
Even when the Ox concentration is reduced, a sufficient amount of spray urea water N flows through the urea water spray nozzle 6. As a result, troubles such as clogging of nozzle pores due to a precipitation hardened product such as this type of conventional denitration system are completely eliminated, and the denitration treatment of exhaust gas by the selective catalytic reduction catalyst method using urea water as a reducing agent is highly efficient. Moreover, it can be done safely. Further, in the present invention,
Since the urea concentration of the sprayed urea water N is automatically adjusted so that the urea amount required to reduce the NOx concentration in the exhaust gas to a predetermined value is supplied, unreacted ammonia caused by excessive urea supply There is no fear of causing problems such as discharge. Further, in the present invention, when the urea water spray is stopped, the spray urea water N in the urea water spray nozzle 6 is replaced with the water W. Therefore, after the spray of the spray urea water N is stopped, the exhaust gas G or the like remains. The spray urea water N in the nozzle 6 is boiled by the heat, and solid matters are not deposited to block the nozzle pores. The present invention has excellent practical effects as described above.
【図１】本発明を実施した排ガス脱硝装置の第１実施例
の説明図である。FIG. 1 is an explanatory diagram of a first embodiment of an exhaust gas denitration device embodying the present invention.
【図２】尿素水噴霧ノズルの縦断面図である。FIG. 2 is a vertical cross-sectional view of a urea water spray nozzle.
【図３】噴霧尿素水の噴霧流量を一定とした場合のエン
ジン出力即ち排出ＮＯX 濃度と噴霧尿素水の尿素濃度と
の関係線図である。FIG. 3 is a relationship diagram of the engine output, that is, the exhaust NO x concentration and the urea concentration of the spray urea water when the spray flow rate of the spray urea water is constant.
【図４】本発明を実施した排ガス脱硝装置の第２実施例
の説明図である。FIG. 4 is an explanatory view of a second embodiment of an exhaust gas denitration device embodying the present invention.
【図５】ディーゼルエンジンの出力と、排ガス内のＮＯ
ｘ濃度及び排ガス温度との関係線図である。FIG. 5: Diesel engine output and NO in exhaust gas
It is a relational diagram with x concentration and exhaust gas temperature.
Ｇは排ガス、Ｎは噴霧尿素水、Ｎ1 は尿素水原液、Ａは
空気、Ｗは水（軟水又は純水）、１は熱機関（ディーゼ
ルエンジン等）、２は脱硝反応器、３は排熱回収ボイ
ラ、４は排ガスダクト、５は排気筒、６は尿素水噴霧ノ
ズル、７は尿素水・空気混合部、８は尿素水供給管、９
はコンプレッサ、１０は空気供給管、１１はＮＯｘ計、
１２は尿素水原液タンク、１３は尿素水原液供給ポン
プ、１４は水（軟水又は純水）タンク、１５は水供給ポ
ンプ、１６は混合弁、１７は出力検出装置、１８はコン
トローラ、１９、２０はインバータ、２１は水供給ポン
プ用モータ、２２は尿素水原液供給ポンプ用モータ、２
３、２４は電磁弁。G is exhaust gas, N is sprayed urea water, N 1 is urea aqueous solution, A is air, W is water (soft water or pure water), 1 is a heat engine (diesel engine, etc.), 2 is a denitration reactor, and 3 is exhaust. Heat recovery boiler, 4 exhaust gas duct, 5 exhaust stack, 6 urea water spray nozzle, 7 urea water / air mixing section, 8 urea water supply pipe, 9
Is a compressor, 10 is an air supply pipe, 11 is a NOx meter,
12 is a urea water stock solution tank, 13 is a urea water stock solution supply pump, 14 is a water (soft water or pure water) tank, 15 is a water supply pump, 16 is a mixing valve, 17 is an output detection device, 18 is a controller, 19, 20 Is an inverter, 21 is a water supply pump motor, 22 is a urea aqueous solution supply pump motor, 2
3 and 24 are solenoid valves.
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 53/36 ＺＡＢ Continuation of front page (51) Int.Cl. 6 Identification number Office reference number FI technical display location B01D 53/36 ZAB
Claims (4)
を用いた排ガスの脱硝処理方法に於いて、尿素水原液
（Ｎ1 ）と水（Ｗ）とを混合して排ガス（Ｇ）内へ噴霧
する噴霧尿素水（Ｎ）を形成すると共に、排ガス（Ｇ）
内のＮＯｘ濃度に応じてコントローラ（１８）により尿
素水原液（Ｎ1 ）と水（Ｗ）の混合比を調整し、前記噴
霧尿素水（Ｎ）の流量を常に設置値以上の流量に保持す
ると共に、噴霧尿素水（Ｎ）の尿素濃度を、排ガス
（Ｇ）内のＮＯｘ濃度を設定値に低減するのに必要な尿
素量が供給される値に保持することを特徴とする排ガス
の脱硝処理方法。1. A method for denitration of exhaust gas using a selective catalytic reduction catalyst using urea water as a reducing agent, wherein a urea water stock solution (N 1 ) and water (W) are mixed in the exhaust gas (G). Atomized urea water (N) that is sprayed to
The controller (18) adjusts the mixing ratio of the urea water stock solution (N 1 ) and water (W) according to the NOx concentration in the inside, and the flow rate of the spray urea water (N) is always maintained at a flow rate higher than the set value. At the same time, the exhaust gas denitration treatment is characterized in that the urea concentration of the spray urea water (N) is maintained at a value at which the urea amount necessary for reducing the NOx concentration in the exhaust gas (G) to a set value is supplied. Method.
らの信号又はＮＯｘ計（１１）からの信号をコントロー
ラ（１８）への入力信号とした請求項１に記載の排ガス
の脱硝処理方法。2. The denitration treatment of exhaust gas according to claim 1, wherein a signal from the output detection device (17) of the heat engine (1) or a signal from the NOx meter (11) is used as an input signal to the controller (18). Method.
の調整を、コントローラ（１８）により混合弁（１６）
の開度を制御するか、若しくはコントローラ（１８）に
より尿素水原液供給ポンプ用モータ（２２）及び水供給
ポンプ用モータ（２１）の回転数を制御することによ
り、行なうようにした請求項１又は請求項２に記載の排
ガスの脱硝処理方法。3. The mixing valve (16) is adjusted by a controller (18) to adjust the mixing ratio of the urea aqueous solution (N 1 ) and water (W).
Or the controller (18) controls the number of revolutions of the urea water stock solution supply pump motor (22) and the water supply pump motor (21). The method for denitrifying exhaust gas according to claim 2.
供給を停止する直前の一定時間のあいだ、尿素水原液
（Ｎ1 ）の混合を停止するようにした請求項１、請求項
２又は請求項３に記載の排ガスの脱硝処理方法。4. The method according to claim 1, wherein the mixing of the urea solution stock solution (N 1 ) is stopped for a certain period of time immediately before stopping the supply of the spray urea water (N) into the exhaust gas (G). The method for denitration treatment of exhaust gas according to claim 2 or claim 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7020851A JPH08206459A (en) | 1995-02-09 | 1995-02-09 | Denitration treatment of exhaust gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7020851A JPH08206459A (en) | 1995-02-09 | 1995-02-09 | Denitration treatment of exhaust gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08206459A true JPH08206459A (en) | 1996-08-13 |
Family
ID=12038609
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7020851A Pending JPH08206459A (en) | 1995-02-09 | 1995-02-09 | Denitration treatment of exhaust gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08206459A (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007000782A (en) * | 2005-06-24 | 2007-01-11 | Samson Co Ltd | Denitrification apparatus for automatically getting rid of clogging of urea water jetting nozzle |
| JP2007000783A (en) * | 2005-06-24 | 2007-01-11 | Samson Co Ltd | Denitrification apparatus for preventing clogging of urea water jetting nozzle |
| JP2008536044A (en) * | 2005-04-13 | 2008-09-04 | グルンドフォス ノノックス エー／エス | Mixing device for mixing urea and air |
| JP2010163985A (en) * | 2009-01-16 | 2010-07-29 | Bosch Corp | Exhaust emission control device for internal combustion engine |
| CN102844095A (en) * | 2010-01-20 | 2012-12-26 | 泛亚有限公司 | System for denitrifying exhaust gas capable of preventing blockages in a urea water inflow path and an injection nozzle, and device for supplying urea water capable of preventing the coagulation of urea water |
| EP2583740A2 (en) * | 2010-06-21 | 2013-04-24 | Panasia Co., Ltd. | Reducing-agent supply device and an exhaust gas nitrogen-removal system using the same |
| JP2015091699A (en) * | 2014-12-25 | 2015-05-14 | ヤンマー株式会社 | Exhaust gas purification system for engine of ship |
| FR3115820A1 (en) | 2020-11-04 | 2022-05-06 | Renault S.A.S | Method and system for decrystallizing an exhaust line of an internal combustion engine, in particular Diesel |
| WO2022097690A1 (en) * | 2020-11-06 | 2022-05-12 | 大同メタル工業株式会社 | Recovery system |
-
1995
- 1995-02-09 JP JP7020851A patent/JPH08206459A/en active Pending
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8371113B2 (en) | 2005-04-13 | 2013-02-12 | Grundfos Nonox A/S | Mixing device for mixing urea and air |
| JP2008536044A (en) * | 2005-04-13 | 2008-09-04 | グルンドフォス ノノックス エー／エス | Mixing device for mixing urea and air |
| JP2007000783A (en) * | 2005-06-24 | 2007-01-11 | Samson Co Ltd | Denitrification apparatus for preventing clogging of urea water jetting nozzle |
| JP2007000782A (en) * | 2005-06-24 | 2007-01-11 | Samson Co Ltd | Denitrification apparatus for automatically getting rid of clogging of urea water jetting nozzle |
| JP4673145B2 (en) * | 2005-06-24 | 2011-04-20 | 株式会社サムソン | Denitration device that automatically eliminates clogging of urea water injection nozzle |
| JP2010163985A (en) * | 2009-01-16 | 2010-07-29 | Bosch Corp | Exhaust emission control device for internal combustion engine |
| CN102844095A (en) * | 2010-01-20 | 2012-12-26 | 泛亚有限公司 | System for denitrifying exhaust gas capable of preventing blockages in a urea water inflow path and an injection nozzle, and device for supplying urea water capable of preventing the coagulation of urea water |
| EP2527028A4 (en) * | 2010-01-20 | 2017-10-11 | Panasia Co., Ltd. | System for denitrifying exhaust gas capable of preventing blockages in a urea water inflow path and an injection nozzle, and device for supplying urea water capable of preventing the coagulation of urea water |
| EP2583740A2 (en) * | 2010-06-21 | 2013-04-24 | Panasia Co., Ltd. | Reducing-agent supply device and an exhaust gas nitrogen-removal system using the same |
| JP2013528749A (en) * | 2010-06-21 | 2013-07-11 | パンアジア カンパニー リミテッド | Reducing agent supply device and exhaust gas denitrification system using the same |
| EP2583740A4 (en) * | 2010-06-21 | 2014-01-15 | Panasia Co Ltd | Reducing-agent supply device and an exhaust gas nitrogen-removal system using the same |
| JP2015091699A (en) * | 2014-12-25 | 2015-05-14 | ヤンマー株式会社 | Exhaust gas purification system for engine of ship |
| FR3115820A1 (en) | 2020-11-04 | 2022-05-06 | Renault S.A.S | Method and system for decrystallizing an exhaust line of an internal combustion engine, in particular Diesel |
| WO2022097690A1 (en) * | 2020-11-06 | 2022-05-12 | 大同メタル工業株式会社 | Recovery system |
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