JP2004237258A

JP2004237258A - Wet type flue gas desulfurization equipment

Info

Publication number: JP2004237258A
Application number: JP2003031922A
Authority: JP
Inventors: Motoomi Iwatsuki; 元臣岩月; Hiroshi Ishizaka; 浩石坂; Hirobumi Yoshikawa; 博文吉川; Naoki Oda; 直己尾田
Original assignee: Babcock Hitachi KK
Current assignee: Mitsubishi Power Ltd
Priority date: 2003-02-10
Filing date: 2003-02-10
Publication date: 2004-08-26

Abstract

<P>PROBLEM TO BE SOLVED: To provide wet type flue gas desulfurization equipment provided with an absorption column which attains a high desulfurization rate while decreasing the pressure loss of an exhaust gas stream and which can be miniaturized. <P>SOLUTION: This wet type flue gas desulfurization equipment is provided with a circulation tank 6 for storing an absorbing liquid 5 and the absorption column 1 which is arranged above the tank 6, into which the exhaust gas discharged from a combustion unit such as a boiler is introduced and in which the introduced exhaust gas is brought into gas-liquid contact with the liquid 5 that is withdrawn from the tank 6 and jetted from spray nozzles 13 of spray headers 12 arranged at multiple stages in the flow direction of the exhaust gas. Two-way spray nozzles containing an upward facing spray nozzle and a downward facing spray nozzle are used as the nozzles 13. At or near the lowermost stage, the ratio of the amount of the liquid 5 to be jetted from the upward facing nozzle to that of the liquid 5 to be jetted from the downward facing nozzle ( the amount of upwardly jetted liquid/ the amount of downward jetted liquid ) is made to be 0.1-0.9 and at each of other stages, the ratio of the amount of the liquid 5 to be jetted from the upward facing nozzle to that of the liquid 5 to be jetted from the downward facing nozzle is made equal or almost equal. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、発電用ボイラなどの燃焼装置から排出される排ガス中の二酸化硫黄（ＳＯ_２）を除去する湿式排煙脱硫装置に係わり、特に、双方向スプレノズルを用いた吸収塔を備えた湿式排煙脱硫装置に関するものである。
【０００２】
【従来の技術】
従来技術のスプレ方式を採用した湿式排煙脱硫装置の公知例（特開平５−２８５３３９号公報など）として、脱硫装置を構成する吸収塔の側面図を図７に示す。この湿式排煙脱硫装置は、主に吸収塔本体１、入口ダクト２、出口ダクト３、吸収液循環ポンプ４、循環タンク６、攪拌機７、空気供給管８、ミストエリミネータ９、吸収液抜出し管１０、循環配管１１、スプレヘッダー１２、スプレノズル１３等から構成される。
【０００３】
ボイラから排出される排ガスは、入口ダクト２から吸収塔本体１に導入され、塔頂部に設けられた出口ダクト３から排出される。吸収液循環ポンプ４により送られる循環タンク６内の炭酸カルシウムを含んだ吸収液５がスプレヘッダー１２に設けられたスプレノズル１３から噴射されており、吸収液５と排ガスの気液接触が行われる。このとき吸収液５は排ガス中のＳＯ_２を吸収し、Ｃａ（ＨＳＯ_３）_２を生成する。循環タンク６に落下した吸収液５は、タンク６内を下降し、循環ポンプ４に吸込まれて循環配管１１を経由して再びスプレノズル１３から噴射される。この間に、空気供給管８から供給される空気１４中の酸素により吸収液中のＣａ（ＨＳＯ_３）_２が酸化され、硫酸カルシウム（石膏）が生成される。
【０００４】
また、同一のスプレヘッダー１２のスプレノズル１３から噴射する吸収液５を下方に向けたスプレノズルだけでなく、上方にも向けた双方向スプレノズル１３を設けた吸収塔１の構成が実願昭６０−１０６４６６号（実開昭６２−１３５２９号）のマイクロフィルム、特開平６−１９８１２１号公報の図３、図４、図５に開示されている。
【０００５】
また、上向きのスプレノズルを配置したスプレヘッダーと下向きのスプレノズルを上下方向に隣接して配置したスプレヘッダー群を備えた吸収塔が特開平６−１９８１２１号公報の図１、図２に開示されている。
【０００６】
【特許文献１】
特開平５−２８５３３９号公報（第５項、第１図）
【０００７】
【特許文献２】
実願昭６０−１０６４６６号（実開昭６２−１３５２９号）のマイクロフィルム
【０００８】
【特許文献３】
特開平６−１９８１２１号公報
【０００９】
【発明が解決しようとする課題】
上記従来技術では、高ＳＯ_２濃度の排ガスを処理する場合など、吸収塔内に噴射する吸収液の流量が増加したとき、排ガス流れの圧力損失が増加する問題があった。特に吸収塔を小型化できる双方向スプレノズルを一つのスプレヘッダーに設け、該スプレヘッダーを多段配置した構成では、吸収液の噴射密度が高いので高ＳＯ_２濃度の排ガスを処理する場合には排ガス流れの圧力損失がかなり増加する問題があった。
そこで、本発明の課題は、排ガス流れの圧力損失を低減しつつ、高脱硫率を得られ、しかも小型化が可能な吸収塔を備えた湿式排煙脱硫装置を提案することである。
【００１０】
【課題を解決するための手段】
本発明の上記課題は次の解決手段により達成される。
すなわち、請求項１記載の発明は、吸収液を貯留する循環タンクと、該循環タンクの上側に配置し、ボイラなどの燃焼装置から排出される排ガスを導入し、排ガス流れ方向に多段に配置したスプレヘッダーのスプレノズルから循環タンクから抜き出した吸収液を噴射して排ガスと気液接触させる吸収塔とを設けた湿式排煙脱硫装置において、前記多段に配置した各段のスプレヘッダーのスプレノズルを上向きスプレノズルと下向きスプレノズルを有する双方向スプレノズルとし、最下段又は最下段近傍の双方向スプレノズルの上向きスプレノズルからの吸収液噴射量と下向きスプレノズルからの吸収液噴射量の比（上向き噴射量／下向き噴射量）を０．１〜０．９の範囲内となるスプレノズルを設け、その他の段の双方向スプレノズルの上向きスプレノズルからの吸収液噴射量と下向きスプレノズルからの吸収液噴射量は同量又はほぼ同量とした湿式排煙脱硫装置である。
【００１１】
請求項２記載の発明は、最上段又は最上段近傍の双方向スプレノズルの上下両方向のスプレノズルの吸収液噴射角度を１００〜１６０度の範囲内とする構成である。
【００１２】
また、請求項３記載の発明は、吸収液を貯留する循環タンクと、該循環タンクの上側に配置し、ボイラなどの燃焼装置から排出される排ガスを導入し、排ガス流れ方向に多段に配置したスプレヘッダーのスプレノズルから循環タンクから抜き出した吸収液を噴射して排ガスと気液接触させる吸収塔とを設けた湿式排煙脱硫装置において、前記多段に配置したスプレヘッダーのスプレノズルを上向きスプレノズルと下向きスプレノズルを有する双方向スプレノズルとし、最下段又は最下段近傍の双方向スプレノズルと最上段又は最上段近傍の双方向スプレノズルのそれぞれ上向きスプレノズルからの吸収液噴射量と下向きスプレノズルからの吸収液噴射量の比（上向き噴射量／下向き噴射量）を共に０．１〜０．９の範囲内となるスプレノズルを設け、その他の段の双方向スプレノズルの上向きスプレノズルからの吸収液噴射量と下向きスプレノズルからの吸収液噴射量は同量又はほぼ同量とした湿式排煙脱硫装置である。
【００１３】
請求項４記載の発明は、請求項３記載の発明の最上段又は最上段近傍の該双方向スプレノズルの上下両方向のスプレノズルの吸収液噴射角度を共に１００〜１６０度の範囲内とする構成である。
【００１４】
また、請求項５記載の発明は、請求項３記載の発明の最上段又は最上段近傍の双方向スプレノズルの上向きスプレノズルの吸収液噴射角度を１００〜１６０度の範囲内とし、下向きスプレノズルの吸収液噴射角度を９０度又はほぼ９０度とした構成である。
【００１５】
本発明のスプレノズルの双方向スプレノズルは、スプレヘッダーの同一位置に上下方向に向いたスプレノズルを設けたものに限らず、上向きスプレノズルと下向きスプレノズルの上下方向の位置をずらしてスプレヘッダーに設けた構成でも良い。
【００１６】
【作用】
図７に示す従来技術において、スプレノズル１３は下方に吸収液５を噴射している。塔内を上昇するガス流れの圧力損失は、液滴を常に下方噴射しているスプレノズル１３を通過する際のものがほとんどである。この圧力損失はスプレノズル１３から噴射される吸収液５の流量が多いほど顕著となる。
【００１７】
一方、本発明では、スプレノズルから噴射する吸収液の全流量を下方に向けず、上方にも向けた双方向スプレノズルを用いることにより上下方向に吸収液を噴射する構成を採用する。スプレノズルから噴射される吸収液の液量の一部を上方に向けることにより、スプレノズルを通過するガス流れの圧力損失を低減する。ただし、下方噴射ノズルを双方向ノズルに変更するのみでは、脱硫率が低下する場合がある。すなわち、図７に示した従来技術においては、下方に噴射するスプレノズルにより塔内を上昇するガス流れを均一流速としている。このため、圧力損失が高いものの、ガスと吸収液の気液接触が均一となり、目標とする脱硫率を得ている。
【００１８】
しかし、双方向ノズルを用いることにより、全流量を下方に噴射していたものが、一部を上方に噴射するため、塔内でのガス流れが不均一となり、均一気液接触が得られず、脱硫率が低下する要因となりやすい。そこで本発明では、双方向ノズルを用いることによる脱硫率の低下を、スプレノズルから上下方向に噴射する吸収液噴射流量および噴射角度を調節することにより防止する。
【００１９】
請求項１記載の発明によれば、最下段スプレヘッダーに設けられた双方向スプレノズルでは、最下段又は最下段近傍の双方向スプレノズルの上向きスプレノズルからの吸収液噴射量と下向きスプレノズルからの吸収液噴射量の比（上向き噴射量／下向き噴射量）を０．１〜０．９の範囲内としているので、吸収塔内の排ガス導入部に対向する吸収塔壁面付近に生じた高速流は双方向スプレノズル通過後には均一な流速分布となる。
【００２０】
また、第２段目以降のスプレヘッダーに配置した双方向スプレノズルから噴射される吸収液と排ガスとはスプレノズルの配置位置に拘わらず、各段のスプレヘッダー付近のガス流れに直交する方向の全空間領域にわたり、ほぼ均一な流速で気液接触がなされ、脱硫率が向上する。さらに、第２段目以降のスプレヘッダーに設けられた双方向スプレノズルの液流量は上方向と下方向ともに等しいか又はほぼ等しくしてあるので、従来技術の全スプレ吸収液を下方に噴射する場合よりも、塔内のガス流れの圧力損失が低減できる。また、排ガスが各段のスプレヘッダーに設けられたスプレノズルを通過する際に、スプレヘッダーの形状等により偏流が生じても、吸収液を下方に噴射しているため、流速を均一化することが可能である。さらに、各段のスプレヘッダーの双方向ノズルノズルから上方に噴射した液はガス流れに同伴して、一旦、吸収塔の上部まで吹き上げられたのちに落下し始める。このため、従来技術の下方へのみ噴射するスプレ吸収液よりも塔内での滞留時間が長くなり、脱硫率が向上する。
【００２１】
請求項２記載の発明によれば、前記請求項１記載の発明の作用に加えて、最上段の双方向スプレノズルからの吸収液の下向き噴射量を上向き噴射量を等しく又はほぼ等しくして、最上段の双方向スプレノズルの下向きと上向きの吸収液の噴射角度を１００〜１６０度の範囲内とすることにより、上下両方向の噴射液が液膜をつくり、ガス流れに同伴して上昇する液滴に衝突する。このため排ガスに同伴して最上段のスプレノズル付近を通過する液滴が少なくなり、吸収塔出口に配置されるミストエリミネータに到達する液滴を減少させることが可能となる。さらに、最上段の双方向スプレノズルの下向きの吸収液噴射量が上向きの吸収液噴射量と等しいため、最上段スプレノズルからの噴射吸収液を排ガスが通過する際に生じる圧力損失は少ない。
【００２２】
請求項３記載の発明によれば、最下段の双方向スプレノズルの上向きスプレノズルからの吸収液噴射量と下向きスプレノズルからの吸収液噴射量の比（上向き噴射量／下向き噴射量）を共に０．１〜０．９の範囲内としているので、最上段の双方向スプレノズルから下方に噴射した液滴を、ガス流れに同伴して塔内を上昇してきた液滴に衝突させ、吸収塔出口に設けられるミストエリミネータに到達する液滴量を減少させることができる。
【００２３】
請求項４記載の発明によれば、前記請求項３記載の発明の作用に加えて、前記最上段又は最上段近傍の該双方向スプレノズルの上下両方向のスプレノズルの吸収液噴射角度を共に１００〜１６０度の範囲内とし、前記双方向スプレノズルからの吸収液の下向き噴射量を上向き噴射量より多量にすることにより、さらに確実にミストエリミネータに到達する液滴を減少させることができる。
【００２４】
請求項５記載の発明によれば、前記請求項３記載の発明の作用に加えて、前記最上段又は最上段近傍の双方向スプレノズルの上向きスプレノズルの吸収液噴射角度を１００〜１６０度の範囲内とし、下向きスプレノズルの吸収液噴射角度を９０度又はほぼ９０度としたので、上向き噴射角度がより大きくなり、同じくミストエリミネータを噴霧液滴が通過することを防止し、かつ最上段双方向スプレノズルからの吸収液の下向き噴射量を上向き噴射量より増加させているので噴霧液滴の偏流防止とミストエリミネータの通過防止をさらに確実に行うことができる。
【００２５】
【発明の実施の形態】
以下に本発明を実施例を用いて説明する。
図１は本発明による実施例の湿式排煙脱硫装置の吸収塔の側面図を示す。
図１の吸収塔は図７に示す吸収塔と同様に、主に吸収塔本体１、入口ダクト２、出口ダクト３、吸収液循環ポンプ４、循環タンク６、攪拌機７、空気供給管８、ミストエリミネータ９、吸収液抜出し管１０、循環配管１１、スプレヘッダー１２、スプレノズル１３等から構成される。
【００２６】
そして、ボイラから排出される排ガスは、入口ダクト２から吸収塔本体１に導入され、塔頂部に設けられた出口ダクト３から排出される。吸収液循環ポンプ４から送られる炭酸カルシウムを含んだ吸収液５はガス流れ方向に複数段設けられたスプレヘッダー１２のスプレノズル１３から噴射されるが、一つのスプレヘッダー１２には複数のスプレノズル１３が設けられている。
【００２７】
スプレノズル１３から噴射された吸収液５は排ガスの気液接触をする。このとき吸収液５は排ガス中のＳＯ_２を吸収し、Ｃａ（ＨＳＯ_３）_２を生成する。循環タンク６に落下した吸収液５は、タンク６内を下降し、循環ポンプ４に吸込まれて循環配管１１を経由して再びスプレヘッダー１２のスプレノズル１３から噴射される。この間に、空気供給管８から供給される空気１４中の酸素により吸収液中のＣａ（ＨＳＯ_３）_２が酸化され、硫酸カルシウム（石膏）が生成される。
【００２８】
上記本実施例の吸収塔ではスプレノズル１３の構造に大きな特徴があり、上方と下方の双方向に吸収液を噴射する双方向スプレノズル構造であり、また、最下段の双方向スプレノズル１３は、上方に噴射する液量と下方に噴射する液量の比が約１：３となるように設計されている。
【００２９】
図１に示す実施例において、吸収塔の側壁面に設けられた入口ダクト２より吸収塔１に導入された排ガスは塔内に流入すると同時に上昇し始めるが、その流速分布は均一ではなく、入口ダクト２とは反対側（入口ダクト２と対向する壁面側）において高流速となる。一方、双方向スプレノズル１３の最下段は、下方に噴射する吸収液の液量を上方に噴射する液量の約３倍としてある。最下段の双方向スプレノズル１３からの下方噴射流量を増加させることにより、入口ダクト２とは反対側に生じた高速流は双方向スプレノズル１３通過後に均一な流速分布となる。
【００３０】
また、第２段目以降のスプレヘッダー１２に配置した双方向スプレノズル１３から噴射される吸収液５とガスとは塔内水平方向の全域で均一に気液接触し、脱硫率が向上する。さらに、第２段目以降の双方向スプレノズル１３の液流量は上方向と下方向ともに等しくしてあり、従来技術の全スプレ吸収液流量を下方に噴射する場合よりも、ガス流れの圧力損失を低減できる。また、排ガスがスプレノズル１３の各段を通過する際に、スプレヘッダー１２の形状等により偏流が生じても、吸収液５を下方に噴射しているため、その流速を塔内水平方向の全域で均一化することが可能である。さらに、各段のスプレヘッダー１２の双方向ノズルノズル１３から上方に噴射した液はガス流れに同伴して、一旦、吸収塔１の上部まで吹き上げられた後に落下し始める。このため、従来技術の下方へのみ噴射する吸収液よりも塔内での滞留時間が長くなり、脱硫率が向上する。
【００３１】
従来から知られている吸収塔のスプレノズルとして上方に向けて吸収液を噴射するスプレノズルを用いる方法もあるが、この従来法は本実施例の双方向スプレノズル１３を用いる場合より上述したガス流れの偏流防止効果が少ない。
【００３２】
本実施例の双方向ノズル１３を用い、最下段のスプレノズル１３においてガス流れの偏流防止を行い、第２段目以降のスプレノズル１３を排ガスが通過する際に生じる偏流についても、その都度双方向スプレノズル１３からの噴射吸収液により防止しなければ、脱硫率低下が発生しやすい。
【００３３】
図２は、図１に示した実施例において、最下段の双方向スプレノズル１３からの上向き吸収液噴射流量に対する下向きの吸収液の噴射流量の比を変化させた場合の脱硫率を表したものである。流量比０は全液量下向き、１は全液量上向きに吸収液をスプレノズル１３から噴射する場合に対応する。脱硫率は液量比０の時を１として表してある。液量比が０から増加するに従い脱硫率は向上する。これは、上向きに噴射された吸収液のスプレ流量を増加させることにより、液滴滞留時間が増加するためである。ただし、液量比が０．９を超えると脱硫率が低下する。これは、上向きの吸収液のスプレ流量が増加するに従い、液滴滞留時間は増加するものの、ガス流れの偏流防止効果が減少し、気液接触の頻度が低下するためである。従って、最下段の双方向スプレノズル１３の上向き噴射量に対する下向き噴射量の比は約３倍に限定する必要はなく、０．１〜０．９の範囲内とするのが良い。
【００３４】
【他の実施例】
図３に示す実施例は、スプレヘッダー１２の双方向スプレノズル１３と最上段のスプレヘッダー１２の双方向スプレノズル１３の上向き噴射量と下向き噴射量の比を共に約１：３としている。図１に示した実施例においては、最下段の双方向スプレノズル１３を含めて各段のスプレヘッダー１２の双方向スプレノズル１３の上方に噴射する液滴はガス流れに同伴され、吸収塔内を上昇する。これによって噴射液滴滞留時間は増加するものの、微小液滴は吸収塔最上部まで達してミストエリミネータ９によって捕集される。ガス量および塔形状によってはミストエリミネータ９で捕集される微小液滴の量が多量となり、捕集率が低下する問題が生じる場合がある。
【００３５】
しかし、図３に示す実施例においては、最上段のスプレヘッダー１２の双方向スプレノズル１３の下向き噴射量を上向き噴射量の約３倍としているので、最上段のスプレヘッダー１２の双方向スプレノズル１３から下方に噴射した液滴を、ガス流れに同伴して塔内を上昇してきた液滴に衝突させ、ミストエリミネータ９に到達する液滴量を減少させる。従って、最上段のスプレヘッダー１２の双方向スプレノズル１３の上向き噴射量に対する下向き噴射量の比は約３倍に限定する必要はなく、０．１〜０．９の範囲内とするのが良い。
【００３６】
図４に示す実施例においては、最下段のスプレヘッダー１２の双方向スプレノズル１３の下向き噴射量を上方噴射量の約３倍とし、かつ最上段のスプレヘッダー１２の双方向スプレノズル１３の上下両方向噴射角度を共に約１４０度としていることに特徴がある。最上段のスプレヘッダー１２の双方向スプレノズル１３の下方噴射量と上方噴射量は等しくしている。最上段スプレヘッダー１２の双方向スプレノズル１３の下方と上方の吸収液の噴射角度を約１４０度とすることにより、上下両方向の噴射液が液膜をつくり、ガス流れに同伴して上昇する液滴に衝突する。このためガスに同伴して最上段スプレヘッダー１２のスプレノズル１３付近を通過する液滴が少なくなり、ミストエリミネータ９に到達する液滴を減少させることが可能となる。さらに、最上段スプレヘッダー１２の双方向スプレノズル１３の下向き噴射量と上向き噴射量が等しいため、図３に示した実施例よりも最上段スプレヘッダー１２をガスが通過する際に生じる圧力損失は少ない。最上段のスプレヘッダー１２の双方向スプレノズル１３の下方と上方の吸収液噴射角度は約１４０度に限定されることはなく、約１００〜１６０度であることが望ましい。
【００３７】
図５に示す実施例においては、最下段のスプレヘッダー１２の双方向スプレノズル１３の下方噴射量を上方噴射量の約３倍とし、かつ最上段スプレヘッダー１２の双方向スプレノズル１３の上下両方向の噴射角度を１４０度とし、上向き噴射量と下向き噴射量の比を約１：３としている。図５に示す実施例では図４に示した実施例と同じく最上段スプレヘッダー１２の双方向スプレノズル１３の上下両方向の噴射角度を約１４０度とし、かつ下向き噴射量を上向き噴射量より多量にすることにより、さらに確実にミストエリミネータ９に到達する液滴を減少させることが可能である。
【００３８】
図６に示す実施例においては、最下段のスプレヘッダー１２の双方向スプレノズル１３の下向き噴射量を上向き噴射量の約３倍とし、かつ最上段スプレヘッダー１２の双方向スプレノズル１３の上向き噴射スプレノズル１３の噴射角度を約１４０度、下向き噴射スプレノズル１３の噴射角度を約９０度とし、上向き噴射量と下向き噴射量の比を１：３としている。最上段スプレヘッダー１２の双方向スプレノズル１３の下向き噴射量を増加させることにより、噴霧液滴の偏流防止とミストエリミネータ９の通過防止を行い、かつ上向き噴射角度を大きくすることにより、同じくミストエリミネータ９を噴霧液滴が通過することを防止する効果がある。
【００３９】
本発明の上記各実施例の双方向スプレノズル１３はスプレヘッダー１２の同一位置に上下方向に向いたスプレノズル１３を設けたものに限らず、上向きスプレノズル１３と下向きスプレノズル１３の上下方向の位置をずらしてスプレヘッダー１２に設けた構成でも良い。
【００４０】
【発明の効果】
本発明によれば、吸収塔内でのガス流れの圧力損失低減と脱硫率向上が同時に達成できる。さらに、スプレノズルから上下両方向に吸収液を噴射するため、スプレノズル一つ当たりの液流量が増加し、スプレノズル個数の低減が可能である。こうして従来技術よりも、低コストで、かつ小型・高性能な湿式排煙脱硫装置が得られる。
【図面の簡単な説明】
【図１】本発明の実施例の、最下段スプレヘッダーの双方向スプレノズルにおいて、上方に噴射する液量と下方に噴射する液量の比を約１：３とした吸収塔の側面図である。
【図２】本発明の実施例の、最下段のスプレヘッダー双方向スプレノズルの上向き噴射流量に対する下向き噴射流量の比を変化させた場合の脱硫率を表したものである。
【図３】本発明の実施例の、最上段のスプレヘッダーの双方向スプレノズルの上向き噴射量と下向き噴射量の比を１：３とした吸収塔の側面図である。
【図４】本発明の実施例の、最上段のスプレヘッダーの双方向スプレノズルの上下両方向噴射角度を１４０度とした図である。
【図５】本発明の実施例の、最上段スプレヘッダーの双方向スプレノズルの上下両方向噴射角度を１４０度とし、上向き噴射量と下向き噴射量の比を１：３とした図である。
【図６】本発明の実施例の、最上段スプレヘッダーの双方向スプレノズルの上向き噴射スプレの噴射角度を１４０度、下向き噴射スプレの噴射角度を９０度とし、上向き噴射量と下向き噴射量の比を１：３とした図である。
【図７】従来技術による吸収塔の側面図である。
【符号の説明】
１吸収塔本体２入口ダクト
３出口ダクト４吸収液循環ポンプ
５吸収液６循環タンク
７攪拌機８空気供給管
９ミストエリミネータ１０吸収液抜出し管
１１循環配管１２スプレヘッダー
１３スプレノズル１４空気[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wet flue gas desulfurization device for removing sulfur dioxide (SO ₂ ) in exhaust gas discharged from a combustion device such as a power boiler, and more particularly to a wet flue gas desulfurization device having an absorption tower using a two-way spray nozzle. It relates to a smoke desulfurization device.
[0002]
[Prior art]
FIG. 7 shows a side view of an absorption tower which constitutes a desulfurization apparatus as a known example of a wet flue gas desulfurization apparatus employing a conventional spray method (Japanese Patent Laid-Open No. 5-285339). This wet flue gas desulfurization apparatus mainly includes an absorption tower main body 1, an inlet duct 2, an outlet duct 3, an absorption liquid circulation pump 4, a circulation tank 6, a stirrer 7, an air supply pipe 8, a mist eliminator 9, and an absorption liquid discharge pipe 10. , A circulation pipe 11, a spray header 12, a spray nozzle 13, and the like.
[0003]
The exhaust gas discharged from the boiler is introduced into the absorption tower main body 1 from the inlet duct 2 and discharged from the outlet duct 3 provided at the top of the tower. The absorption liquid 5 containing calcium carbonate in the circulation tank 6 sent by the absorption liquid circulation pump 4 is jetted from the spray nozzle 13 provided on the spray header 12, and gas-liquid contact between the absorption liquid 5 and the exhaust gas is performed. At this time, the absorbing liquid 5 absorbs SO ₂ in the exhaust gas and generates Ca (HSO ₃ ) ₂ . The absorbent 5 that has fallen into the circulation tank 6 descends in the tank 6, is sucked into the circulation pump 4, and is jetted again from the spray nozzle 13 via the circulation pipe 11. During this time, Ca (HSO ₃ ) ₂ in the absorbing solution is oxidized by oxygen in the air 14 supplied from the air supply pipe 8 to generate calcium sulfate (gypsum).
[0004]
Further, the construction of the absorption tower 1 provided with not only the spray nozzles for spraying the absorbing liquid 5 sprayed from the spray nozzles 13 of the same spray header 12 downward but also the bidirectional spray nozzles 13 for upward direction is disclosed in Japanese Utility Model Application No. 60-106466. No. (Japanese Utility Model Application Laid-Open No. 62-13529), and FIGS. 3, 4 and 5 of JP-A-6-198121.
[0005]
Further, an absorption tower having a spray header in which an upward spray nozzle is arranged and a spray header group in which a downward spray nozzle is vertically arranged adjacent to each other is disclosed in FIGS. 1 and 2 of JP-A-6-198121. .
[0006]
[Patent Document 1]
JP-A-5-285339 (Section 5, FIG. 1)
[0007]
[Patent Document 2]
Microfilm of Japanese Utility Model Application No. 60-106466 (Japanese Utility Model Application Laid-open No. 62-13529)
[Patent Document 3]
JP-A-6-198121
[Problems to be solved by the invention]
In the above prior art, when the flow rate of the absorbing solution injected into the absorption tower is increased, for example, when treating the exhaust gas having a high SO ₂ concentration, there is a problem that the pressure loss of the exhaust gas flow increases. In particular, in a configuration in which a two-way spray nozzle capable of downsizing the absorption tower is provided in one spray header, and the spray header is arranged in multiple stages, the exhaust density of the absorbing solution is high, so that when exhaust gas having a high SO ₂ concentration is treated, the exhaust gas flow However, there is a problem that the pressure loss increases considerably.
Therefore, an object of the present invention is to provide a wet flue gas desulfurization apparatus having an absorption tower capable of obtaining a high desulfurization rate and reducing the size while reducing the pressure loss of the exhaust gas flow.
[0010]
[Means for Solving the Problems]
The above object of the present invention is achieved by the following means.
That is, according to the first aspect of the present invention, the circulation tank for storing the absorbing liquid and the circulation tank are disposed above the circulation tank, and the exhaust gas discharged from a combustion device such as a boiler is introduced and arranged in multiple stages in the exhaust gas flow direction. In a wet flue gas desulfurization device provided with an absorption tower that injects the absorbing liquid extracted from the circulation tank from the spray nozzle of the spray header and makes gas-liquid contact with the exhaust gas, the spray nozzles of the spray headers of each stage arranged in the multi-stage are upward spray nozzles. A two-way spray nozzle having a downward spray nozzle and a downward spray nozzle, and the ratio of the amount of absorbent injected from the upward spray nozzle and the amount of absorbent injected from the downward spray nozzle in the lowermost stage or the vicinity of the lowermost stage (upward injection amount / downward injection amount) A spray nozzle within the range of 0.1 to 0.9 is provided, and the upward direction of the bidirectional spray nozzle in other stages is upward. Absorbing solution injection amount from the spray nozzles and the absorption liquid injection quantity from the downward spray nozzle is wet type exhaust gas desulfurization apparatus with the same amount or substantially the same amount.
[0011]
The second aspect of the present invention is configured such that the upper and lower two-way spray nozzles in the vicinity of the uppermost stage have a spray nozzle in both upper and lower directions in which the absorbent injection angle is in the range of 100 to 160 degrees.
[0012]
According to the third aspect of the present invention, a circulation tank for storing the absorbing liquid and an exhaust gas discharged from a combustion device such as a boiler are disposed above the circulation tank and arranged in multiple stages in the exhaust gas flow direction. In a wet flue gas desulfurization device provided with an absorption tower that injects the absorbing liquid extracted from the circulation tank from the spray nozzle of the spray header and makes gas-liquid contact with the exhaust gas, the spray nozzles of the spray header arranged in multiple stages are upward spray nozzles and downward spray nozzles. The two-way spray nozzle having the lowermost stage or the vicinity of the lowermost stage and the uppermost stage or the two-way spray nozzle near the uppermost stage respectively has a ratio of the amount of the absorbent sprayed from the upward spray nozzle to the amount of the absorbent sprayed from the downward spray nozzle ( Spray nozzle with both upward injection amount / downward injection amount within the range of 0.1 to 0.9 Provided, absorbing fluid injection quantity from the absorption liquid injection amount and a downward spray nozzle from the upward spray nozzle bidirectional spray nozzles other stage is a wet flue gas desulfurization apparatus with the same amount or substantially the same amount.
[0013]
According to a fourth aspect of the present invention, both the upper and lower spray nozzles in the upper and lower directions of the bidirectional spray nozzle in the vicinity of the uppermost stage of the invention according to the third aspect have an absorption liquid injection angle within a range of 100 to 160 degrees. .
[0014]
According to a fifth aspect of the present invention, the absorbent spray angle of the upward spray nozzle of the bidirectional spray nozzle at or near the uppermost stage in the third aspect of the present invention is in the range of 100 to 160 degrees, and the absorbent liquid of the downward spray nozzle is The injection angle is 90 degrees or almost 90 degrees.
[0015]
The two-way spray nozzle of the spray nozzle of the present invention is not limited to the spray nozzle provided with a vertically oriented spray nozzle at the same position of the spray header, and may be a configuration in which the upward spray nozzle and the downward spray nozzle are provided on the spray header by shifting the vertical position. good.
[0016]
[Action]
In the prior art shown in FIG. 7, the spray nozzle 13 sprays the absorbing liquid 5 downward. Most of the pressure loss of the gas flow rising in the tower is caused when the gas passes through the spray nozzle 13 which always jets the liquid droplets downward. This pressure loss becomes more remarkable as the flow rate of the absorbing liquid 5 injected from the spray nozzle 13 increases.
[0017]
On the other hand, the present invention employs a configuration in which the absorbing liquid is ejected vertically by using a two-way spray nozzle that is directed upward, instead of directing the total flow rate of the absorbing liquid ejected from the spray nozzle downward. By directing a part of the amount of the absorbing liquid injected from the spray nozzle upward, pressure loss of a gas flow passing through the spray nozzle is reduced. However, simply changing the lower injection nozzle to the bidirectional nozzle may lower the desulfurization rate. That is, in the prior art shown in FIG. 7, the gas flow that rises in the tower by the spray nozzle that injects downward has a uniform flow velocity. For this reason, although the pressure loss is high, the gas-liquid contact between the gas and the absorbing liquid becomes uniform, and the target desulfurization rate is obtained.
[0018]
However, by using a two-way nozzle, the entire flow rate was jetted downward, but a part of the jet was jetted upward, so that the gas flow in the tower became uneven and uniform gas-liquid contact could not be obtained. , Which is likely to cause a decrease in the desulfurization rate. Therefore, in the present invention, a decrease in the desulfurization rate due to the use of the two-way nozzle is prevented by adjusting the injection flow rate and the injection angle of the absorbing liquid jetted vertically from the spray nozzle.
[0019]
According to the first aspect of the present invention, in the two-way spray nozzle provided in the lowermost spray header, the amount of the absorbent sprayed from the upward spray nozzle and the upper part of the two-way spray nozzle near the lowermost spray nozzle and the absorbent spray from the downward spray nozzle Since the ratio of the amounts (upward injection amount / downward injection amount) is in the range of 0.1 to 0.9, the high-speed flow generated near the wall surface of the absorption tower facing the exhaust gas introduction section in the absorption tower is a two-way spray nozzle. After passage, the flow velocity distribution becomes uniform.
[0020]
Further, regardless of the position of the spray nozzle, the absorbing liquid and the exhaust gas injected from the bidirectional spray nozzles arranged in the spray headers of the second and subsequent stages are all spaces in the direction orthogonal to the gas flow near the spray headers in each stage. Gas-liquid contact is made at a substantially uniform flow rate over the region, and the desulfurization rate is improved. Further, since the liquid flow rates of the bidirectional spray nozzles provided in the second and subsequent spray headers are equal or substantially equal in both the upward and downward directions, the conventional spray spray liquid is sprayed downward. Thus, the pressure loss of the gas flow in the tower can be reduced. In addition, when the exhaust gas passes through the spray nozzle provided in the spray header of each stage, even if a drift occurs due to the shape of the spray header, etc., since the absorbing liquid is jetted downward, the flow velocity can be made uniform. It is possible. Further, the liquid jetted upward from the two-way nozzle nozzle of the spray header of each stage is accompanied by the gas flow, is once blown up to the upper part of the absorption tower, and then starts falling. For this reason, the residence time in the tower is longer than that of the spray absorption liquid which is injected only downward in the related art, and the desulfurization rate is improved.
[0021]
According to the second aspect of the present invention, in addition to the operation of the first aspect, the downward injection amount of the absorbing liquid from the uppermost two-way spray nozzle is set to be equal or substantially equal to the upward injection amount, and By setting the jetting angle of the downward and upward absorbing liquid in the upper two-way spray nozzle to be in the range of 100 to 160 degrees, the liquid in both the upper and lower directions forms a liquid film, and the liquid drops rise as the gas flows. collide. Therefore, the number of droplets passing near the uppermost spray nozzle along with the exhaust gas is reduced, and the number of droplets reaching the mist eliminator arranged at the outlet of the absorption tower can be reduced. Further, since the downwardly-absorbed liquid injection amount of the uppermost bidirectional spray nozzle is equal to the upwardly-absorbed liquid injection amount, the pressure loss generated when the exhaust gas passes through the injected absorbent from the uppermost spray nozzle is small.
[0022]
According to the third aspect of the present invention, the ratio of the amount of the absorbing liquid ejected from the upward spray nozzle to the amount of the absorbing liquid ejected from the downward spray nozzle (upward injection amount / downward injection amount) in both cases is 0.1. Since it is within the range of 0.9, the droplets jetted downward from the uppermost bidirectional spray nozzle collide with the droplets rising in the column accompanying the gas flow, and are provided at the outlet of the absorption tower. The amount of droplets reaching the mist eliminator can be reduced.
[0023]
According to the fourth aspect of the present invention, in addition to the operation of the third aspect of the present invention, the upper and lower two-way spray nozzles in the vicinity of the uppermost stage both have an upper and lower spray nozzle spray angle of 100 to 160. By setting the temperature in the range of degrees and making the downward injection amount of the absorbing liquid from the bidirectional spray nozzle larger than the upward injection amount, the number of droplets reaching the mist eliminator can be reduced more reliably.
[0024]
According to the fifth aspect of the present invention, in addition to the operation of the third aspect, the absorbent spray angle of the upward spray nozzle of the bidirectional spray nozzle at or near the uppermost stage is within a range of 100 to 160 degrees. And, since the absorption liquid ejection angle of the downward spray nozzle is set to 90 degrees or almost 90 degrees, the upward injection angle becomes larger, preventing the spray droplets from also passing through the mist eliminator, and from the uppermost bidirectional spray nozzle. Since the downward injection amount of the absorbing liquid is larger than the upward injection amount, it is possible to more reliably prevent the spray droplets from drifting and passing through the mist eliminator.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to examples.
FIG. 1 is a side view of an absorption tower of a wet flue gas desulfurization apparatus according to an embodiment of the present invention.
The absorption tower in FIG. 1 is mainly composed of an absorption tower main body 1, an inlet duct 2, an outlet duct 3, an absorption liquid circulation pump 4, a circulation tank 6, a stirrer 7, an air supply pipe 8, a mist The eliminator 9 includes an eliminator 9, an absorbent extraction pipe 10, a circulation pipe 11, a spray header 12, a spray nozzle 13, and the like.
[0026]
The exhaust gas discharged from the boiler is introduced into the absorption tower main body 1 from the inlet duct 2 and discharged from the outlet duct 3 provided at the top of the tower. The absorption liquid 5 containing calcium carbonate sent from the absorption liquid circulation pump 4 is jetted from the spray nozzles 13 of the spray header 12 provided in a plurality of stages in the gas flow direction, and a plurality of spray nozzles 13 are provided on one spray header 12. Is provided.
[0027]
The absorbing liquid 5 injected from the spray nozzle 13 makes gas-liquid contact with the exhaust gas. At this time, the absorbing liquid 5 absorbs SO ₂ in the exhaust gas and generates Ca (HSO ₃ ) ₂ . The absorbent 5 that has fallen into the circulation tank 6 descends in the tank 6, is sucked into the circulation pump 4, and is jetted again from the spray nozzle 13 of the spray header 12 via the circulation pipe 11. During this time, Ca (HSO ₃ ) ₂ in the absorbing solution is oxidized by oxygen in the air 14 supplied from the air supply pipe 8 to generate calcium sulfate (gypsum).
[0028]
The absorption tower according to the present embodiment has a great feature in the structure of the spray nozzle 13, and has a bidirectional spray nozzle structure in which the absorbing liquid is jetted upward and downward in both directions. It is designed such that the ratio of the amount of liquid to be ejected and the amount of liquid to be ejected downward is about 1: 3.
[0029]
In the embodiment shown in FIG. 1, the exhaust gas introduced into the absorption tower 1 from the inlet duct 2 provided on the side wall surface of the absorption tower starts to rise at the same time as flowing into the tower, but the flow velocity distribution is not uniform, and The flow velocity becomes high on the side opposite to the duct 2 (the wall surface side facing the inlet duct 2). On the other hand, in the lowermost stage of the bidirectional spray nozzle 13, the amount of the absorbing liquid ejected downward is set to be about three times the amount of the liquid ejected upward. By increasing the downward injection flow rate from the lowermost bidirectional spray nozzle 13, the high-speed flow generated on the side opposite to the inlet duct 2 has a uniform flow velocity distribution after passing through the bidirectional spray nozzle 13.
[0030]
Further, the absorbent 5 and the gas ejected from the bidirectional spray nozzles 13 arranged on the spray headers 12 of the second and subsequent stages are in uniform gas-liquid contact throughout the horizontal direction in the tower, and the desulfurization rate is improved. Further, the liquid flow rates of the bidirectional spray nozzles 13 in the second and subsequent stages are equal in both the upward and downward directions, and the pressure loss of the gas flow is reduced as compared with the case where the total spray absorption liquid flow rate of the related art is jetted downward. Can be reduced. Also, when the exhaust gas passes through each stage of the spray nozzle 13, even if a drift occurs due to the shape of the spray header 12, etc., since the absorbing liquid 5 is jetted downward, the flow velocity is reduced throughout the horizontal direction in the tower. It is possible to make it uniform. Further, the liquid jetted upward from the bidirectional nozzle nozzle 13 of the spray header 12 of each stage is accompanied by the gas flow, is once blown up to the upper part of the absorption tower 1, and then starts to fall. For this reason, the residence time in the tower is longer than that of the absorption liquid which is injected only downward in the related art, and the desulfurization rate is improved.
[0031]
There is a conventionally known method of using a spray nozzle for injecting an absorbing liquid upward as a spray nozzle of an absorption tower. However, this conventional method uses the above-described non-uniform flow of gas flow as compared with the case of using the bidirectional spray nozzle 13 of this embodiment. Less prevention effect.
[0032]
Using the bidirectional nozzle 13 of the present embodiment, the gas flow is prevented from drifting in the lowermost spray nozzle 13, and the drift generated when the exhaust gas passes through the spray nozzles 13 in the second and subsequent stages is also changed each time. If it is not prevented by the injection and absorption liquid from 13, the desulfurization rate tends to decrease.
[0033]
FIG. 2 shows the desulfurization rate when the ratio of the downward absorbent injection flow rate to the upward absorbent injection flow rate from the lowermost two-way spray nozzle 13 in the embodiment shown in FIG. 1 is changed. is there. The flow ratio 0 corresponds to the case where the absorbing liquid is ejected from the spray nozzle 13 in the downward direction of the total liquid amount and the upward direction of the total liquid amount. The desulfurization rate is expressed as 1 when the liquid volume ratio is 0. As the liquid volume ratio increases from 0, the desulfurization rate increases. This is because the droplet residence time is increased by increasing the spray flow rate of the upwardly injected absorbent. However, when the liquid amount ratio exceeds 0.9, the desulfurization rate decreases. This is because, as the spray flow rate of the upward absorbing liquid increases, the droplet residence time increases, but the effect of preventing the gas flow from drifting decreases, and the frequency of gas-liquid contact decreases. Therefore, the ratio of the downward injection amount to the upward injection amount of the lowermost bidirectional spray nozzle 13 does not need to be limited to about three times, but is preferably in the range of 0.1 to 0.9.
[0034]
[Other embodiments]
In the embodiment shown in FIG. 3, the ratio between the upward injection amount and the downward injection amount of the two-way spray nozzle 13 of the spray header 12 and the two-way spray nozzle 13 of the uppermost spray header 12 is about 1: 3. In the embodiment shown in FIG. 1, droplets ejected above the bidirectional spray nozzles 13 of the spray header 12 of each stage, including the lowermost bidirectional spray nozzle 13, are entrained in the gas flow and rise in the absorption tower. I do. As a result, the ejection droplet residence time increases, but the minute droplets reach the top of the absorption tower and are collected by the mist eliminator 9. Depending on the amount of gas and the shape of the tower, the amount of the fine droplets collected by the mist eliminator 9 becomes large, which may cause a problem that the collection rate is reduced.
[0035]
However, in the embodiment shown in FIG. 3, the downward injection amount of the bidirectional spray nozzle 13 of the uppermost spray header 12 is set to be about three times the upward injection amount. The droplets jetted downward collide with the droplets rising in the tower accompanying the gas flow, and the amount of the droplets reaching the mist eliminator 9 is reduced. Therefore, the ratio of the downward injection amount to the upward injection amount of the bidirectional spray nozzle 13 of the uppermost spray header 12 does not need to be limited to about three times, but is preferably in the range of 0.1 to 0.9.
[0036]
In the embodiment shown in FIG. 4, the downward injection amount of the bidirectional spray nozzle 13 of the lowermost spray header 12 is set to about three times the upward injection amount, and the upper and lower two-way spray nozzles 13 of the spray header 12 of the uppermost spray header 12 are used. The feature is that both angles are about 140 degrees. The lower injection amount and the upper injection amount of the bidirectional spray nozzle 13 of the uppermost spray header 12 are made equal. By setting the jetting angle of the absorbing liquid below and above the bidirectional spray nozzle 13 of the uppermost spray header 12 to about 140 degrees, the liquid jetting liquid in both the upper and lower directions forms a liquid film, and the liquid droplet rises with the gas flow. Collide with For this reason, the number of droplets passing near the spray nozzle 13 of the uppermost spray header 12 accompanying the gas decreases, and the number of droplets reaching the mist eliminator 9 can be reduced. Further, since the downward injection amount and the upward injection amount of the bidirectional spray nozzle 13 of the uppermost spray header 12 are equal, the pressure loss generated when the gas passes through the uppermost spray header 12 is smaller than in the embodiment shown in FIG. . The absorption liquid spray angle below and above the bidirectional spray nozzle 13 of the uppermost spray header 12 is not limited to about 140 degrees, but is preferably about 100 to 160 degrees.
[0037]
In the embodiment shown in FIG. 5, the downward injection amount of the bidirectional spray nozzle 13 of the lowermost spray header 12 is set to be approximately three times the upper injection amount, and the upper and lower spray nozzles 13 of the uppermost spray header 12 inject both upward and downward directions. The angle is 140 degrees, and the ratio of the upward injection amount to the downward injection amount is about 1: 3. In the embodiment shown in FIG. 5, as in the embodiment shown in FIG. 4, the upper and lower spray angles of the bidirectional spray nozzle 13 of the uppermost spray header 12 are set to approximately 140 degrees, and the downward injection amount is set to be larger than the upward injection amount. This makes it possible to more reliably reduce the number of droplets that reach the mist eliminator 9.
[0038]
In the embodiment shown in FIG. 6, the downward spray amount of the bidirectional spray nozzle 13 of the lowermost spray header 12 is set to be approximately three times the upward spray amount, and the upward spray spray nozzle 13 of the bidirectional spray nozzle 13 of the uppermost spray header 12. Is about 140 degrees, the injection angle of the downward injection spray nozzle 13 is about 90 degrees, and the ratio of the upward injection amount to the downward injection amount is 1: 3. Increasing the downward spray amount of the bidirectional spray nozzle 13 of the uppermost spray header 12 prevents drifting of spray droplets and preventing passage of the mist eliminator 9, and increasing the upward spray angle also increases the mist eliminator 9. This has the effect of preventing the spray droplets from passing through.
[0039]
The bidirectional spray nozzle 13 of each of the above embodiments of the present invention is not limited to the one in which the spray nozzle 13 that is vertically oriented at the same position of the spray header 12 is provided, and the vertical spray nozzle 13 and the downward spray nozzle 13 are shifted in the vertical direction. A configuration provided in the spray header 12 may be used.
[0040]
【The invention's effect】
According to the present invention, it is possible to simultaneously reduce the pressure loss of the gas flow in the absorption tower and improve the desulfurization rate. Further, since the absorbing liquid is ejected from the spray nozzle in both the up and down directions, the liquid flow rate per spray nozzle is increased, and the number of spray nozzles can be reduced. In this way, a compact and high-performance wet flue gas desulfurization device can be obtained at lower cost than in the prior art.
[Brief description of the drawings]
FIG. 1 is a side view of an absorption tower according to an embodiment of the present invention, in which the ratio of the amount of liquid ejected upward to the amount of liquid ejected downward is about 1: 3 in the bidirectional spray nozzle of the lowermost spray header. .
FIG. 2 shows the desulfurization rate when the ratio of the downward injection flow rate to the upward injection flow rate of the lowermost spray header bidirectional spray nozzle of the embodiment of the present invention is changed.
FIG. 3 is a side view of an absorption tower according to an embodiment of the present invention in which the ratio of the upward injection amount to the downward injection amount of the bidirectional spray nozzle of the uppermost spray header is 1: 3.
FIG. 4 is a view showing an example in which the upper and lower spray headers of the uppermost spray header have an injection angle of 140 degrees in both the upper and lower directions.
FIG. 5 is a view of the embodiment of the present invention, in which the bidirectional spray nozzle of the uppermost spray header has an upper and lower two-way injection angle of 140 degrees and a ratio of an upward injection amount to a downward injection amount of 1: 3.
FIG. 6 shows the ratio of the upward injection amount to the downward injection amount of the bidirectional spray nozzle of the uppermost spray header according to the embodiment of the present invention, in which the injection angle of the upward injection spray is 140 degrees and the injection angle of the downward injection spray is 90 degrees. FIG.
FIG. 7 is a side view of an absorption tower according to the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Absorption tower main body 2 Inlet duct 3 Outlet duct 4 Absorbent circulation pump 5 Absorbent 6 Circulation tank 7 Stirrer 8 Air supply pipe 9 Mist eliminator 10 Absorbent extraction pipe 11 Circulation pipe 12 Spray header 13 Spray nozzle 14 Air

Claims

A circulation tank for storing the absorbing liquid, and disposed above the circulation tank, exhaust gas discharged from a combustion device such as a boiler was introduced, and extracted from the circulation tank from a spray nozzle of a spray header arranged in multiple stages in the exhaust gas flow direction. In a wet flue gas desulfurization device provided with an absorption tower that injects the absorbent and makes gas-liquid contact with the exhaust gas,
The spray nozzles of the spray header of each stage arranged in the multi-stage are a bidirectional spray nozzle having an upward spray nozzle and a downward spray nozzle, and the absorption liquid injection amount from the upward spray nozzle and the absorption from the downward spray nozzle of the lowermost stage or the bidirectional spray nozzle near the lowermost stage. A spray nozzle having a ratio of liquid injection amount (upward injection amount / downward injection amount) in the range of 0.1 to 0.9 is provided, and the absorption liquid injection amount from the upward spray nozzle of the bidirectional spray nozzle in the other stages and the downward spray nozzle. Wherein the amount of the absorbent injected from the apparatus is the same or substantially the same.

2. A wet flue gas desulfurization apparatus according to claim 1, wherein the upper and lower two-way spray nozzles in the vicinity of the uppermost stage have a spray nozzle in both upper and lower directions in which the absorbing liquid is sprayed at an angle of 100 to 160 degrees.

A circulation tank for storing the absorbing liquid and the exhaust gas discharged from a combustion device such as a boiler arranged above the circulation tank were introduced and extracted from the circulation tank from the spray nozzle of the spray header arranged in multiple stages in the exhaust gas flow direction. In a wet flue gas desulfurization device provided with an absorption tower that injects the absorption liquid and makes gas-liquid contact with the exhaust gas,
The spray nozzles of the spray headers arranged in multiple stages are a bidirectional spray nozzle having an upward spray nozzle and a downward spray nozzle, and a bidirectional spray nozzle near the lowermost stage or the lowermost stage and a bidirectional spray nozzle near the uppermost stage or the uppermost stage absorb from the upward spray nozzle, respectively. A spray nozzle is provided in which the ratio of the liquid injection amount to the absorption liquid injection amount from the downward spray nozzle (upward injection amount / downward injection amount) is both within the range of 0.1 to 0.9, and the upward direction of the bidirectional spray nozzle in the other stages is upward. A wet flue gas desulfurization apparatus characterized in that the amount of the absorbing liquid injected from the spray nozzle and the amount of the absorbing liquid injected from the downward spray nozzle are equal or almost equal.

4. The wet flue gas desulfurization apparatus according to claim 3, wherein both of the spray nozzles in the upper and lower directions of the two-way spray nozzle in the uppermost stage or in the vicinity of the uppermost stage are in the range of 100 to 160 degrees.

The upward spray nozzle of the two-way spray nozzle at or near the uppermost stage has an absorbent spray angle of 100 to 160 degrees, and the downward spray nozzle has an absorbent spray angle of 90 degrees or almost 90 degrees. Item 4. A wet flue gas desulfurization device according to Item 3.