JP2013220376A

JP2013220376A - Apparatus and method for seawater desulfurization

Info

Publication number: JP2013220376A
Application number: JP2012092765A
Authority: JP
Inventors: Yoshiaki Mitsui; 良晃三井; Noriyuki Imada; 典幸今田; Shigeto Omine; 成人大峰; Hiroshi Ishizaka; 浩石坂
Original assignee: Babcock Hitachi KK
Current assignee: Mitsubishi Power Ltd
Priority date: 2012-04-16
Filing date: 2012-04-16
Publication date: 2013-10-28

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption and the size of an oxidation pit by enhancing oxidation performance for sulfurous acid in a seawater desulfurization apparatus provided with a pre-scrubber.SOLUTION: A seawater desulfurization apparatus is arranged which has a desulfurization absorption part to make contact with sprayed seawater in a flow path for exhaust gas discharged from a combustion device and an absorbing liquid storage part to store the seawater absorbing sulfur in the exhaust gas. Because an oxidation catalyst supply means is installed to supply a sulfurous acid oxidation catalyst to the seawater as the absorbing liquid fed to the seawater desulfurization apparatus, or the seawater discharged from the seawater desulfurization apparatus, or the seawater in the absorbing liquid storage part of seawater desulfurization apparatus, oxidation performance to sulfurous acid can be maintained, while desulfurization of the exhaust gas by seawater is under way.

Description

本発明は、火力発電用ボイラプラント等において、燃焼排ガスに含まれる硫黄酸化物（ＳＯ_２）や煤塵を除去するための吸収剤として、海水を使用する方式の脱硫装置（以下、単に、海水脱硫装置ということもある）に関するものである。 The present invention relates to a desulfurization apparatus that uses seawater as an absorbent for removing sulfur oxide (SO ₂ ) and soot contained in combustion exhaust gas in a boiler plant for thermal power generation (hereinafter simply referred to as seawater desulfurization). Device).

石炭を燃焼させる火力発電用ボイラプラントの例を図５に示す。該火力発電用ボイラプラントは主にボイラ１３、集塵装置１６、ガス−ガスヒータ４４、海水脱硫装置３、煙突２９などから構成される。ボイラ１３で石炭２５を燃焼することにより、生成する排ガスを集塵装置１６に送り、排ガス中の煤塵を除去する。集塵装置１６で除塵された排ガスはガス−ガスヒータ４４で冷却され、海水脱硫装置３に送られて排ガス中のＳＯ_２が海水により吸収され、排ガスから除去される。この排ガスの温度は、供給された海水温度とほぼ等しくなるため、大気中へ放出された際に排ガス中の水蒸気が凝縮して白煙を生じ、景観上の問題から、ガス−ガスヒータ４４で排ガスを再加熱し、白煙が目立たないようにする。この後の排ガスは煙突２９から排出される。 An example of a thermal power generation boiler plant for burning coal is shown in FIG. The boiler plant for thermal power generation mainly includes a boiler 13, a dust collector 16, a gas-gas heater 44, a seawater desulfurization device 3, a chimney 29, and the like. By burning the coal 25 in the boiler 13, the generated exhaust gas is sent to the dust collector 16 and the soot in the exhaust gas is removed. The exhaust gas dedusted in the dust collector 16 gas - is cooled in gas heater 44, is sent to the seawater desulfurization apparatus 3 is SO ₂ in the exhaust gas is absorbed by the sea water, is removed from the exhaust gas. Since the temperature of the exhaust gas is substantially equal to the temperature of the supplied seawater, when discharged into the atmosphere, the water vapor in the exhaust gas is condensed to produce white smoke. Due to landscape problems, the gas-gas heater 44 exhausts the exhaust gas. Reheat the so that white smoke is not noticeable. The exhaust gas after this is discharged from the chimney 29.

また、ボイラ１３で得られた蒸気は蒸気タービン４９に送られ、発電機５０の発電に利用される、また蒸気タービン４９から排出された蒸気を冷却・凝縮するために、ボイラ１３の復水器４２に海水１２を海水供給用ポンプ４５で供給するが、この使用後の海水をスプレ用ポンプ５により海水脱硫装置３のスプレノズル４から噴霧し、排ガス中のＳＯ_２ガスを吸収させる。ＳＯ_２ガスを吸収した海水は低ｐＨとなり、海水中の亜硫酸及び重亜硫酸イオンはＣＯＤ（化学的酸素要求量）源となるため、排水処理設備が別途必要になる。脱硫装置３に供給されない一部の海水１２は酸化ピット４３に供給され、未使用の海水１２中に含まれるアルカリ成分と混合することによりｐＨの回復が図られる。酸化ピット４３では供給された海水の亜硫酸を酸化するために酸化用ガス２７をポンプ５１により供給する。酸化用ガス２７は通常、空気である。酸化された亜硫酸は海洋中に多量に存在するＳＯ_４ ^２−となるため、無害な状態で海洋へ放出することができる。しかし、海水脱硫装置３で海水中に吸収された煤塵は、海洋にそのまま排出される。例えば、１，０００ＭＷ級のボイラ１３において、煤塵は年間で１，５００トン排出される。石炭中にはＨｇ（水銀）やＣｄ（カドミウム）といった有害物質が、微量ではあるが含まれていることから、それぞれ年間にＨｇは２５０ｋｇ、Ｃｄは５２ｋｇが排出され、公害が懸念される。このため、海水脱硫装置３の上流側にプレスクラバを設置して煤塵を除去して、海水脱硫装置３側には煤塵が供給されないシステムも考えられている。 Further, the steam obtained in the boiler 13 is sent to the steam turbine 49 to be used for power generation by the generator 50, and in order to cool and condense the steam discharged from the steam turbine 49, the condenser of the boiler 13 is used. The seawater 12 is supplied to 42 by a seawater supply pump 45, and the seawater after use is sprayed from the spray nozzle 4 of the seawater desulfurization device 3 by the spray pump 5 to absorb SO ₂ gas in the exhaust gas. Seawater that has absorbed SO ₂ gas has a low pH, and sulfurous acid and bisulfite ions in the seawater are sources of COD (chemical oxygen demand). A part of the seawater 12 that is not supplied to the desulfurization apparatus 3 is supplied to the oxidation pit 43, and the pH is recovered by mixing with the alkaline component contained in the unused seawater 12. In the oxidation pit 43, an oxidizing gas 27 is supplied by a pump 51 in order to oxidize the sulfurous acid in the supplied seawater. The oxidizing gas 27 is usually air. Oxidized sulfurous acid becomes SO ₄ ²⁻ present in a large amount in the ocean, and can be released to the ocean in a harmless state. However, the dust absorbed in the seawater by the seawater desulfurization apparatus 3 is discharged as it is to the ocean. For example, in a 1,000 MW class boiler 13, 1,500 tons of dust are discharged annually. Coal contains harmful substances such as Hg (mercury) and Cd (cadmium), although they are contained in trace amounts. As a result, 250 kg of Hg and 52 kg of Cd are discharged each year, and there is concern about pollution. For this reason, a system in which a press club is installed on the upstream side of the seawater desulfurization apparatus 3 to remove the soot and the soot is not supplied to the seawater desulfurization apparatus 3 is also considered.

プレスクラバを備えた海水脱硫装置３として関連するものには、例えば、ヨーロッパ特許第９７１１３９４５号が挙げられる。当該特許発明では、プレスクラバを設置することにより、脱硫装置に煤塵を供給しない構成とし、プレスクラバでの濃縮排水は燃料とともに燃焼処理と石炭灰の増湿に利用されている。しかし、プレスクラバで煤塵を除去することによって海水脱硫装置の酸化性能が低下することに関しては考慮されていない。 For example, European Patent No. 97113945 can be cited as a related one as the seawater desulfurization apparatus 3 provided with a press clubber. In this patented invention, a press scrubber is installed so that dust is not supplied to the desulfurization unit, and the concentrated waste water in the press scrubber is used for combustion treatment and the humidification of coal ash together with fuel. However, no consideration is given to the deterioration of the oxidation performance of the seawater desulfurization apparatus by removing the dust with a press clubber.

ヨーロッパ特許第９７１１３９４５号公報European Patent No. 97113945

上記従来技術は、石炭の燃焼排ガス中に含まれる煤塵をプレスクラバで除去することにより、海水脱硫装置での亜硫酸の酸化性能が低下する点について配慮がされておらず、酸化ブロアの動力増加、酸化ピットのサイズが大きくなる問題があった。 The above prior art does not give consideration to the point that the oxidation performance of sulfurous acid in seawater desulfurization equipment is reduced by removing dust contained in coal combustion exhaust gas with a press clubber. There was a problem that the size of the pits increased.

本発明の課題は、プレクラバを備えた海水脱硫装置において、亜硫酸の酸化性能を高めることで、海水脱硫装置の酸化ピットでのｐＨを回復させるのに必要な海水の量を低減させて、酸化ピットの小型化、動力の低減を図ることにある。 An object of the present invention is to reduce the amount of seawater necessary for recovering the pH in the oxidation pit of the seawater desulfurization device by increasing the oxidation performance of sulfurous acid in the seawater desulfurization device equipped with the preclava, and the oxidation pit Is to reduce the size and power of the machine.

上記課題は、次の解決手段で達成される。
請求項１記載の発明は、燃焼装置から排出される排ガス流路に配置した、噴霧海水と接触させる脱硫吸収部と、該排ガス中の硫黄分を吸収した海水を貯留する吸収液溜め部を有する海水脱硫装置において、該海水脱硫装置に供給される海水又は該海水脱硫装置から排出される海水又は該海水脱硫装置の前記吸収液溜め部の海水に亜硫酸の酸化触媒を供給する酸化触媒供給手段を設けたことを特徴とする海水脱硫装置である。 The above-mentioned subject is achieved by the following solution means.
The invention according to claim 1 has a desulfurization absorption part which is arranged in an exhaust gas flow path discharged from a combustion device and makes contact with sprayed seawater, and an absorption liquid reservoir part which stores seawater that has absorbed sulfur in the exhaust gas. In the seawater desulfurization apparatus, an oxidation catalyst supply means for supplying a sulfurous acid oxidation catalyst to the seawater supplied to the seawater desulfurization apparatus, the seawater discharged from the seawater desulfurization apparatus, or the seawater in the absorption liquid reservoir of the seawater desulfurization apparatus A seawater desulfurization apparatus characterized by being provided.

請求項２記載の発明は、海水脱硫装置の上流側に、該排ガス中の煤塵を除去するプレスクラバを設けることを特徴とする請求項１に記載の海水脱硫装置である。 The invention according to claim 2 is the seawater desulfurization device according to claim 1, wherein a press clubber for removing the dust in the exhaust gas is provided on the upstream side of the seawater desulfurization device.

請求項３記載の発明は、酸化触媒供給手段は海水脱硫装置の吸収液溜め部内に予め浸漬された酸化触媒供給手段、又は脱硫吸収部内に設けた吸収液受け内の吸収液に浸漬された酸化触媒供給手段であることを特徴とする請求項１に記載の海水脱硫装置である。 According to the third aspect of the present invention, the oxidation catalyst supply means is an oxidation catalyst supply means previously immersed in the absorption liquid reservoir of the seawater desulfurization apparatus, or an oxidation immersed in an absorption liquid in an absorption liquid receiver provided in the desulfurization absorption section. The seawater desulfurization apparatus according to claim 1, wherein the seawater desulfurization apparatus is a catalyst supply means.

請求項４記載の発明は、海水脱硫装置の前流側の排ガス流路に集塵装置を配置し、該集塵装置で回収した回収灰から鉄分を回収する鉄分分離装置を設け、前記酸化触媒供給手段に前記鉄分分離装置で得られた鉄分を供給する構成を備えたことを特徴とする請求項１に記載の海水脱硫装置である。 According to a fourth aspect of the present invention, a dust collector is disposed in the exhaust gas flow path on the upstream side of the seawater desulfurization device, an iron separation device is provided for recovering iron from recovered ash recovered by the dust collector, and the oxidation catalyst The seawater desulfurization apparatus according to claim 1, further comprising: a supply unit configured to supply iron obtained by the iron separation apparatus.

請求項５記載の発明は、燃焼装置からの排ガスを脱硫装置内に導入して噴霧海水と接触させ、排ガス中の硫黄分を吸収した海水を一時的に溜めておき、該一時的に溜めておいた海水を再び前記排ガスと接触させる海水脱硫方法において、海水脱硫に利用するための海水又は前記海水脱硫後の海水に亜硫酸の酸化触媒を供給することを特徴とする海水脱硫方法である。 The invention according to claim 5 introduces the exhaust gas from the combustion device into the desulfurization device and makes it contact with the sprayed seawater, temporarily stores the seawater that has absorbed the sulfur content in the exhaust gas, and temporarily stores the seawater. In the seawater desulfurization method in which Oita seawater is brought into contact with the exhaust gas again, a sulfurous acid oxidation catalyst is supplied to seawater to be used for seawater desulfurization or seawater after the seawater desulfurization.

請求項６記載の発明は、燃焼装置からの排ガスをプレスクラバ内に導入して噴霧海水と接触させて、予め排ガス中の煤塵を除去した後に、煤塵を除去した排ガスを脱硫装置内に導入して噴霧海水と接触させ、排ガス中の硫黄分を吸収した海水を一時的に溜めておき、該一時的に溜めておいた海水を再び前記排ガスと接触させることを特徴とする請求項５記載海水脱硫方法である。 According to the sixth aspect of the present invention, the exhaust gas from the combustion device is introduced into the press scrubber and brought into contact with the spray seawater to remove the dust in the exhaust gas in advance, and then the exhaust gas from which the dust has been removed is introduced into the desulfurization device. 6. Seawater desulfurization according to claim 5, wherein the seawater that has been brought into contact with the sprayed seawater, the seawater that has absorbed sulfur in the exhaust gas is temporarily stored, and the seawater that has been temporarily stored is brought into contact with the exhaust gas again. Is the method.

請求項７記載の発明は、前記酸化触媒は鉄又は鉄イオンであることを特徴とする請求項５に記載の海水脱硫方法である。 The invention according to claim 7 is the seawater desulfurization method according to claim 5, wherein the oxidation catalyst is iron or iron ions.

請求項８記載の発明は、前記鉄イオンは、鉄と脱硫装置内に一時的に溜められた脱硫後の海水との接触により生成させることを特徴とする請求項７に記載の海水脱硫方法である。 The invention according to claim 8 is the seawater desulfurization method according to claim 7, wherein the iron ions are generated by contact between iron and seawater after desulfurization temporarily stored in a desulfurization apparatus. is there.

請求項９記載の発明は、前記鉄及び前記鉄イオンは、燃焼装置から排出した排ガスを集塵装置で灰分を回収して得た灰中の鉄を分離して用いることを特徴とする請求項５に記載の海水脱硫方法である。 The invention according to claim 9 is characterized in that the iron and the iron ions are used by separating the iron in the ash obtained by collecting the ash from the exhaust gas discharged from the combustion device with a dust collector. 5. The seawater desulfurization method according to 5.

亜硫酸の酸化を促進させる触媒として、例えば鉄又は鉄イオンを用いることができるがその他にマンガン（Ｍｎ）、コバルト（Ｃｏ）又は銅（Ｃｕ）などの金属又は金属イオン等を用いても良い。 As a catalyst for promoting oxidation of sulfurous acid, for example, iron or iron ions can be used, but other metals such as manganese (Mn), cobalt (Co), copper (Cu), or metal ions may be used.

（作用）
海水脱硫装置で用いられる脱硫前の海水中もしくは脱硫後の海水中もしくは海水脱硫装置の液溜め部に、例えば鉄又は鉄イオンを供給することで、鉄又は鉄イオンが亜硫酸の酸化を促進させる触媒効果を有するようになるので、プレスクラバで除塵されたことによる、海水脱硫装置側での亜硫酸の酸化性能の低下を懸念する必要がない。 (Function)
Catalyst that promotes oxidation of sulfurous acid by supplying, for example, iron or iron ions to seawater before desulfurization used in seawater desulfurization equipment, in seawater after desulfurization, or to a reservoir of seawater desulfurization equipment Since it comes to have an effect, it is not necessary to worry about the deterioration of the oxidation performance of sulfurous acid on the seawater desulfurization device side due to the dust removal by the press clubber.

本発明によれば、プレスクラバを備えた海水脱硫装置で用いられる脱硫前の海水もしくは脱硫後の海水中に鉄又は鉄イオンを供給することにより、亜硫酸の酸化性能が向上し、酸化ブロアの動力低減及び酸化ピットを小型化する効果がある。 According to the present invention, by supplying iron or iron ions into seawater before or after desulfurization used in a seawater desulfurization apparatus equipped with a press scrubber, the oxidation performance of sulfurous acid is improved and the power of the oxidation blower is reduced. In addition, there is an effect of reducing the size of the oxidation pit.

請求項１、５記載の発明によれば、海水脱硫装置の前流側にスクラバーを配置していない場合について、海水による排ガスの脱硫処理に酸化触媒供給手段から供給される亜硫酸の酸化触媒（鉄（Ｆｅ）、マンガン（Ｍｎ）、コバルト（Ｃｏ）、銅（Ｃｕ））などを吸収液（海水）に供給することで、亜硫酸の酸化性能を維持することができ、酸化ブロア５１の動力を低減、並びに酸化ピット４３の小型化を図ることができる。 According to the first and fifth aspects of the present invention, in the case where no scrubber is arranged on the upstream side of the seawater desulfurization apparatus, an oxidation catalyst for sulfurous acid (iron) supplied from the oxidation catalyst supply means for the desulfurization treatment of the exhaust gas using seawater. (Fe), manganese (Mn), cobalt (Co), copper (Cu)), etc. are supplied to the absorption liquid (seawater), so that the oxidation performance of sulfurous acid can be maintained and the power of the oxidation blower 51 is reduced. In addition, the size of the oxidation pit 43 can be reduced.

請求項２、６記載の発明によれば、請求項１、５記載の発明の効果に加えて、海水脱硫装置の前流側にスクラバーを配置して海水中の重金属成分をスクラバーで予め除いておいても、海水による排ガスの脱硫処理の後に亜硫酸の酸化触媒を吸収液（海水）に供給することで亜硫酸の酸化性能が低下することがない。 According to the second and sixth aspects of the invention, in addition to the effects of the first and fifth aspects of the invention, a scrubber is disposed on the upstream side of the seawater desulfurization apparatus, and heavy metal components in the seawater are removed beforehand by the scrubber. However, the oxidation performance of sulfurous acid does not deteriorate by supplying the sulfurous acid oxidation catalyst to the absorbent (seawater) after the desulfurization treatment of the exhaust gas with seawater.

請求項３、７、８記載の発明によれば、請求項１、５記載の発明の効果に加えて、海水脱硫装置の吸収液溜め部内に予め酸化触媒を浸漬しておくか、又は脱硫吸収部内に設けた吸収液受け５２（図２）内の吸収液に酸化触媒を浸漬しておくことで、酸化触媒を別途海水脱硫装置に供給する手間が省ける。
また、脱硫吸収部内に設けた吸収液受け（吸収液溜め部１１より上方位置にある液受け）５２内の吸収液に浸漬された酸化触媒を用いる場合には図２に示すようにｐＨが吸収液溜め部１１内の吸収液より低い海水を鉄と接触させることができるので鉄分の溶解がより促進される。 According to the third, seventh, and eighth aspects of the invention, in addition to the effects of the first and fifth aspects, the oxidation catalyst is immersed in the absorption liquid reservoir of the seawater desulfurization apparatus in advance, or the desulfurization absorption. By immersing the oxidation catalyst in the absorption liquid in the absorption liquid receiver 52 (FIG. 2) provided in the section, it is possible to save the trouble of supplying the oxidation catalyst separately to the seawater desulfurization apparatus.
Further, when using an oxidation catalyst immersed in an absorbent in an absorbent receiver (liquid receiver located above the absorbent reservoir 11) provided in the desulfurization absorber, the pH is absorbed as shown in FIG. Since seawater lower than the absorbent in the liquid reservoir 11 can be brought into contact with iron, dissolution of iron is further promoted.

請求項４、９記載の発明によれば、請求項１、５記載の発明の効果に加えて、酸化触媒として燃焼装置の排ガスから回収した鉄分を用いることができ、鉄分を新たに調達する必要がないのでコストに有利である。 According to the inventions of claims 4 and 9, in addition to the effects of the inventions of claims 1 and 5, iron recovered from the exhaust gas of the combustion device can be used as an oxidation catalyst, and it is necessary to newly procure iron This is advantageous in terms of cost.

本発明になる海水脱硫装置の吸収液溜め部内に鉄を供給し、鉄を溶出させる実施例の脱硫系統図である。It is a desulfurization system figure of the Example which supplies iron in the absorption liquid reservoir part of the seawater desulfurization apparatus which becomes this invention, and elutes iron. 本発明になる海水脱硫装置の吸収液溜め部から一部の液を抜き出し、別置きのタンクで鉄を溶出させ、該吸収液溜め部に供給する実施例の脱硫系統図である。It is a desulfurization system diagram of the Example which extracts a part liquid from the absorption liquid reservoir part of the seawater desulfurization apparatus which becomes this invention, elutes iron with a separate tank, and supplies to this absorption liquid reservoir part. 本発明になる集塵装置の回収灰から得られた鉄を海水脱硫装置に供給する実施例の脱硫系統図である。It is a desulfurization system diagram of the Example which supplies the iron obtained from the collection | recovery ash of the dust collector which becomes this invention to a seawater desulfurization apparatus. 海水脱硫時に亜硫酸の酸化性能に及ぼす金属イオンの影響を示した実施例の脱硫系統図である。It is the desulfurization system | strain diagram of the Example which showed the influence of the metal ion on the oxidation performance of sulfurous acid at the time of seawater desulfurization. 従来の石炭燃焼排ガスを処理する海水脱硫装置の実施例の脱硫系統図である。It is a desulfurization system figure of the Example of the seawater desulfurization apparatus which processes the conventional coal combustion exhaust gas. ｐＨと希釈後の海水量との関係を示す図である。It is a figure which shows the relationship between pH and the amount of seawater after dilution.

本発明の実施の形態について図面とともに説明する。なお、本実施例で使用する構成の中で従来技術と共通する構成については、その構成と作用の説明を省略する。 Embodiments of the present invention will be described with reference to the drawings. In addition, about the structure which is common in a prior art in the structure used by a present Example, the description of the structure and an effect | action is abbreviate | omitted.

本発明のプレスクラバを備えた海水脱硫装置の構成の一例を図１に示す。プレスクラバ４８を備えた海水脱硫装置３は、主にスプレノズル４、スプレ用ポンプ５、ミストエリミネータ８、酸化用ガス供給部９、攪拌機１０、吸収液溜め部１１、酸化ピット４３、プレスクラバ４８などから構成される。プレスクラバ４８は、スプレ用ポンプ３６、スプレノズル７、吸収液溜め部２１、攪拌機１０、ミストエリミネータ３５から構成される。 An example of the structure of the seawater desulfurization apparatus provided with the press clubber of the present invention is shown in FIG. The seawater desulfurization apparatus 3 provided with a press scrubber 48 mainly comprises a spray nozzle 4, a spray pump 5, a mist eliminator 8, an oxidizing gas supply unit 9, a stirrer 10, an absorbing liquid reservoir 11, an oxidation pit 43, a press scrubber 48, and the like. Is done. The press club 48 includes a spray pump 36, a spray nozzle 7, an absorption liquid reservoir 21, a stirrer 10, and a mist eliminator 35.

プレスクラバ４８の吸収液溜め部２１に海水もしくは工水等を供給し、該海水をスプレ用ポンプ３６を用いてプレスクラバ４８の排ガス導入部に設けられたスプレノズル７から排ガス１に噴霧する。ここで工水とは海水よりも液中の塩素濃度が低い水のことであり、以下海水もしくは工水等を海水又は吸収液ということにする。 Seawater or industrial water or the like is supplied to the absorbing liquid reservoir 21 of the press clubber 48, and the seawater is sprayed onto the exhaust gas 1 from the spray nozzle 7 provided in the exhaust gas introduction section of the press clubber 48 using the spray pump 36. Here, the industrial water is water having a lower chlorine concentration in seawater than seawater. Hereinafter, seawater or industrial water will be referred to as seawater or absorbing liquid.

スプレノズル７から排ガス１に噴霧される吸収液（海水）により排ガス１中の煤塵は除去されて吸収液溜め部２１で回収されるか、又はプレスクラバ４８の排ガス出口部に設けられたミストエリミネータ３５で回収される。吸収液溜め部２１で回収された海水からなる吸収液は再度、スプレ用ポンプ３６を用いて循環しながら排ガスへ噴霧される。濃縮した煤塵を含む吸収液は一部抜き出されて図示していない排水処理設備において固液分離され、分離された固体は海洋に放出されないよう、別途廃棄処分される。 The dust in the exhaust gas 1 is removed by the absorbing liquid (seawater) sprayed on the exhaust gas 1 from the spray nozzle 7 and recovered by the absorbing liquid reservoir 21 or by a mist eliminator 35 provided at the exhaust gas outlet of the press clubber 48. Collected. The absorption liquid composed of seawater collected in the absorption liquid reservoir 21 is sprayed again on the exhaust gas while circulating using the spray pump 36. Part of the absorbing liquid containing concentrated soot and dust is extracted and separated into solid and liquid in a wastewater treatment facility (not shown), and the separated solid is separately disposed of so as not to be released into the ocean.

ミストエリミネータ３５より後流側の海水脱硫装置３は吸収液溜め部１１とその上部にある脱硫吸収部２６からなり、該脱硫吸収部２６に設けられたスプレノズル４には吸収液溜め部１１からスプレ用ポンプ５により供給された吸収液（海水）は噴霧され、排ガス中のＳＯ_２ガスを吸収して排ガスの脱硫を行う。また、ボイラで生成した蒸気は蒸気タービン（図示せず）で使用した後は復水器４２に回収される。該復水器４２で得られる温度が上昇した海水１２は、スプレ用ポンプ５によりスプレノズル４から噴霧されて排ガス中の脱硫に利用される。 The seawater desulfurization device 3 on the downstream side of the mist eliminator 35 is composed of an absorption liquid reservoir 11 and a desulfurization absorption section 26 located above the absorption liquid reservoir 11. The absorbing liquid (seawater) supplied by the pump 5 is sprayed and absorbs SO ₂ gas in the exhaust gas to desulfurize the exhaust gas. Moreover, the steam produced | generated with the boiler is collect | recovered by the condenser 42, after using with a steam turbine (not shown). The seawater 12 having an increased temperature obtained by the condenser 42 is sprayed from the spray nozzle 4 by the spray pump 5 and used for desulfurization in the exhaust gas.

脱硫吸収部２６に落下した噴霧吸収液６中の亜硫酸は、酸化用ブロア５４を用いて酸化空気供給部９から供給される空気を攪拌機１０で攪拌することにより酸化され、酸化ピット４３に送られて、石膏を分離回収した残りの液は排水１７として排出される。
なお、吸収液溜め部２１で回収された海水も吸収液に吸収された煤塵、精製した石膏等の固形物が沈降するのを防止するために攪拌機１０で攪拌される。 The sulfurous acid in the spray absorbing liquid 6 that has fallen on the desulfurization absorbing section 26 is oxidized by stirring the air supplied from the oxidizing air supply section 9 with the stirrer 10 using the oxidizing blower 54, and sent to the oxidation pit 43. Thus, the remaining liquid from which the gypsum has been separated and recovered is discharged as drainage 17.
The seawater collected in the absorption liquid reservoir 21 is also agitated by the stirrer 10 in order to prevent solids such as dust and purified gypsum absorbed in the absorption liquid from settling.

本発明の海水脱硫装置３では、吸収液溜め部１１内に供給した鉄２０（この鉄２０は予め吸収液溜め部１１内の吸収液中に浸漬している。）と亜硫酸を吸収したｐＨ＝２．３〜４．０とｐＨの低い海水を接触させることにより、鉄から鉄イオン（Ｆｅ^２＋イオン）が海水側に溶出する。このＦｅ^２＋イオンは亜硫酸の酸化性能を高める効果がある。 In the seawater desulfurization apparatus 3 according to the present invention, the iron 20 (the iron 20 is previously immersed in the absorbent in the absorbent reservoir 11) and the sulfurous acid supplied into the absorbent reservoir 11 and pH = By contacting seawater having a low pH with 2.3 to 4.0, iron ions (Fe ²⁺ ions) are eluted from the iron to the seawater side. This Fe ²⁺ ion has an effect of improving the oxidation performance of sulfurous acid.

図４に、プレスクラバ４８で処理した煤塵を含まない海水とプレスクラバ４８で処理していない煤塵１．９ｍｇ／Ｌを含んだ海水での亜硫酸の酸化速度比を示す。亜硫酸の酸化速度比とは、煤塵を含む海水で酸化速度を測定した結果を１．０とした場合に、煤塵を含まない海水での酸化速度を相対比で表したものである。プレスクラバ４８で除塵した海水は、除塵しない海水に比べて、酸化性能が約７０％程度低下することが分かる。 FIG. 4 shows the oxidation rate ratio of sulfurous acid in seawater containing no dust treated with the press scrubber 48 and seawater containing 1.9 mg / L of dust not treated with the press scrubber 48. The oxidation rate ratio of sulfurous acid is a relative ratio of the oxidation rate in seawater not containing soot when the result of measuring the oxidation rate in seawater containing soot is 1.0. It can be seen that the seawater dedusted by the press scrubber 48 has about 70% lower oxidation performance than seawater without dust removal.

しかし、本発明のように煤塵の代わりに海水中にＦｅ^２＋イオンを０．１ｍｇ／Ｌ供給することにより、亜硫酸の酸化性能を回復することができる。鉄イオンの生成量はｐＨや鉄の表面の状態にもよるが、鉄の単位表面積、単位時間あたりの溶出量で示すと、約４０ｇ／（ｍ^２・ｈ）であり、鉄の表面積を考慮することでＦｅ^２＋イオンの供給量を調整できる。一方、吸収液溜め部１１内の鉄２０の表面が酸化用ガス２７で酸化されて酸化皮膜を形成し、鉄２０の溶解速度を低下させるおそれがある。吸収液溜め部１１の攪拌機１０の近くに鉄２０を設置することで、吸収液６の流れによる鉄２０の表面の磨耗が促進され、鉄２０の溶解速度の低下を防止できる。 However, the oxidation performance of sulfurous acid can be recovered by supplying 0.1 mg / L of Fe ²⁺ ions into seawater instead of soot as in the present invention. The amount of iron ions produced depends on the pH and the surface state of the iron, but it is about 40 g / (m ² · h) in terms of the unit surface area of iron and the amount of elution per unit time. By doing so, the supply amount of Fe ²⁺ ions can be adjusted. On the other hand, the surface of the iron 20 in the absorbing liquid reservoir 11 is oxidized by the oxidizing gas 27 to form an oxide film, and the dissolution rate of the iron 20 may be reduced. By installing the iron 20 near the stirrer 10 in the absorbent reservoir 11, wear of the surface of the iron 20 due to the flow of the absorbent 6 is promoted, and a decrease in the dissolution rate of the iron 20 can be prevented.

プレスクラバ４８で排ガスの除塵をしても、吸収液溜め部１１で鉄２０又は鉄イオンを供給することによって、亜硫酸の酸化性能を維持することができ、酸化用ブロア５１、５４の動力を低減し、酸化ピット４３の小型化を図ることができる。 Even if dust is removed from the exhaust gas by the press clubber 48, the oxidation performance of sulfurous acid can be maintained by supplying iron 20 or iron ions from the absorption liquid reservoir 11, and the power of the oxidizing blowers 51 and 54 can be reduced. In addition, the size of the oxidation pit 43 can be reduced.

図６にｐＨと希釈後の海水量との関係を示す。
ｐＨ＝６の場合の希釈後の海水量を１として、ｐＨ＝４の場合の希釈後の海水量を相対的に表記した。 FIG. 6 shows the relationship between pH and the amount of seawater after dilution.
The amount of seawater after dilution when pH = 6 was 1, and the amount of seawater after dilution when pH = 4 was expressed relatively.

ｐＨ＝４の場合、ｐＨ＝６よりも希釈後の海水量が４０％と少なくなるため、酸化ピット４３のサイズもその分小さくすることができる。
また、液中の亜硫酸濃度が低くなると、亜硫酸の酸化性能は低くなる。このため、ｐＨ＝６の場合、ｐＨ＝４の場合よりも希釈後の液中亜硫酸濃度が低くなるため、亜硫酸の酸化性能が低くなる。 In the case of pH = 4, the amount of seawater after dilution is 40% less than that of pH = 6, so that the size of the oxidation pit 43 can be reduced accordingly.
Further, when the concentration of sulfurous acid in the liquid is lowered, the oxidation performance of sulfurous acid is lowered. For this reason, in the case of pH = 6, since the concentration of sulfurous acid in the liquid after dilution is lower than in the case of pH = 4, the oxidation performance of sulfurous acid is lowered.

本発明の場合、ｐＨ＝４で酸化できるため、亜硫酸の酸化性能がｐＨ＝６の場合よりも高い。このため、ｐＨ＝４の場合とｐＨ＝６の場合とで相対的に動力を比較すると、本発明の場合、動力を低減できる。 In the present invention, since oxidation can be performed at pH = 4, the oxidation performance of sulfurous acid is higher than that at pH = 6. For this reason, in the case of this invention, a motive power can be reduced if a motive power is compared relatively in the case of pH = 4 and the case of pH = 6.

本発明の他の実施例を図２に示す。図１に示す装置では吸収液溜め部１１に鉄２０を供給したが、図２に示すように、排ガスと気液接触して脱硫吸収部２６から排出した吸収液（海水）６を溜めるタンク３８に鉄２０（この鉄２０は予めタンク３８内の吸収液中に浸漬している）を供給し、脱硫後のｐＨがｐＨ＝２．３〜４．０と低い吸収液（海水）６を鉄２０と接触させることにより、Ｆｅ^２＋イオンを吸収液（海水）６中に溶出させ、この液を吸収液溜め部１１に供給することもできる。その他の構成は図１で説明した構成と同一であり、説明は省略する。 Another embodiment of the present invention is shown in FIG. In the apparatus shown in FIG. 1, iron 20 is supplied to the absorbing liquid reservoir 11, but as shown in FIG. 2, a tank 38 that stores the absorbing liquid (seawater) 6 discharged from the desulfurization absorber 26 in gas-liquid contact with the exhaust gas. Is supplied with iron 20 (the iron 20 is preliminarily immersed in the absorbing solution in the tank 38), and the absorbing solution (seawater) 6 having a low pH after desulfurization of 2.3 to 4.0 is supplied to the iron. By contacting with 20, Fe ²⁺ ions can be eluted into the absorption liquid (seawater) 6, and this liquid can be supplied to the absorption liquid reservoir 11. Other configurations are the same as those described with reference to FIG.

脱硫吸収部２６で排ガスと気液接触した後の吸収液６の液受け５２を吸収液溜め部１１の吸収液液面５３より高い位置に設け、液受け５２で回収した吸収液６をタンク３８に供給することで、吸収液溜め部１１中の吸収液６よりも、ｐＨの低い海水を鉄２０と接触させることができるので、鉄２０の溶解を促進することができる。また、吸収液溜め部１１に供給する酸化空気２７をタンク３８中では供給していないため、鉄２０の表面に酸化皮膜を形成しにくくなり、鉄２０の溶解の阻害を防止できる。 The liquid receiver 52 of the absorbent 6 after contacting the exhaust gas with the exhaust gas in the desulfurization absorber 26 is provided at a position higher than the absorbent liquid level 53 of the absorbent reservoir 11, and the absorbent 6 recovered by the liquid receiver 52 is stored in the tank 38. Since the seawater whose pH is lower than that of the absorbent 6 in the absorbent reservoir 11 can be brought into contact with the iron 20, dissolution of the iron 20 can be promoted. Further, since the oxidized air 27 supplied to the absorbing liquid reservoir 11 is not supplied in the tank 38, it is difficult to form an oxide film on the surface of the iron 20, and inhibition of dissolution of the iron 20 can be prevented.

本発明のさらに他の実施例を図３に示す。集塵装置１６（図５）から回収される集塵装置回収灰４６を用いること以外の構成は、図１で説明した構成と同一であり、説明は省略する。 Yet another embodiment of the present invention is shown in FIG. The configuration other than using the dust collector recovery ash 46 recovered from the dust collector 16 (FIG. 5) is the same as the configuration described with reference to FIG.

集塵装置１６（図５）から回収される集塵装置回収灰４６は灰中に３〜５％程度の多量の鉄を含んでいる。鉄分離装置４７を用いて、鉄と灰４６を分離し、鉄側を吸収液溜め部１１又は酸化ピット４３に供給することにより、亜硫酸の酸化性能を高めることができる。鉄分離装置４７は、例えば、磁石又は電磁石を用いることで鉄を回収することができる。鉄表面の酸化皮膜の形成により低下した鉄イオンの溶出量を補うように鉄の供給量を調整することで、亜硫酸の酸化性能を維持することができる。また、集塵装置回収灰４６の灰中の鉄は灰中の酸性成分により、溶けやすい形態で存在するため、亜硫酸の酸化性能を高めることができる。 The dust collector recovery ash 46 recovered from the dust collector 16 (FIG. 5) contains a large amount of iron of about 3 to 5% in the ash. By separating the iron and ash 46 using the iron separator 47 and supplying the iron side to the absorption liquid reservoir 11 or the oxidation pit 43, the oxidation performance of sulfurous acid can be enhanced. The iron separator 47 can collect iron by using, for example, a magnet or an electromagnet. By adjusting the supply amount of iron so as to compensate for the elution amount of iron ions reduced by the formation of an oxide film on the iron surface, the oxidation performance of sulfurous acid can be maintained. Moreover, since iron in the ash of the dust collector ash 46 is present in an easily soluble form due to acidic components in the ash, the oxidation performance of sulfurous acid can be enhanced.

また、図１、図２及び図３において、図示してはいないが脱硫吸収部２６においてスプレノズル４で排ガス中に噴霧する前の海水に鉄２０又は鉄イオンを供給しても良い。鉄イオン濃度が高くなることにより、排ガスと接触して液滴が吸収液溜め部１１に落下する間に、排ガス中の酸素との反応により亜硫酸の酸化が促進される。また、酸化ピット４３に鉄２０又は鉄イオンを供給しても、亜硫酸の酸化が促進される。 Although not shown in FIGS. 1, 2, and 3, iron 20 or iron ions may be supplied to seawater before being sprayed into the exhaust gas by the spray nozzle 4 in the desulfurization absorption unit 26. By increasing the iron ion concentration, the oxidation of sulfurous acid is promoted by the reaction with oxygen in the exhaust gas while the liquid droplet comes into contact with the exhaust gas and falls into the absorbing liquid reservoir 11. Even if iron 20 or iron ions are supplied to the oxidation pits 43, the oxidation of sulfurous acid is promoted.

また、本実施例では、プレスクラバ４８で煤塵を除去する海水脱硫装置３について説明したが、プレスクラバ４８を用いない海水脱硫装置３においても、海水脱硫装置３で用いる脱硫前の海水もしくは脱硫後の海水に、鉄２０を供給することにより、亜硫酸の酸化を促進することができる。 In the present embodiment, the seawater desulfurization apparatus 3 that removes soot and dust with the press clubber 48 has been described. However, even in the seawater desulfurization apparatus 3 that does not use the press clubber 48, the seawater before or after desulfurization used in the seawater desulfurization apparatus 3 Further, by supplying iron 20, oxidation of sulfurous acid can be promoted.

また、石炭焚きボイラに限らす、重油焚きボイラの海水脱硫装置においても、海水脱硫装置で用いる脱硫前の海水もしくは脱硫後の海水に鉄２０を供給することにより、亜硫酸の酸化を促進できる。 Moreover, even in the seawater desulfurization apparatus for heavy oil fired boilers, not limited to coal fired boilers, the oxidation of sulfurous acid can be promoted by supplying iron 20 to seawater before or after desulfurization used in the seawater desulfurization apparatus.

１排ガス２出口排ガス
３海水脱硫装置４，７スプレノズル
５スプレ用ポンプ６吸収液（海水）
８，３５ミストエリミネータ９酸化用ガス供給部
１０攪拌機１１吸収液溜め部
１２海水１３ボイラ
１６集塵装置１７排水
２０鉄２１吸収液溜め部
２５石炭２６脱硫吸収部
２７酸化用ガス２９煙突
３６スプレ用ポンプ３８タンク
３９ポンプ４２復水器
４３酸化ピット４４ガス−ガスヒータ
４５海水供給用ポンプ４６集塵装置回収灰
４７鉄分離装置４８プレスクラバ
４９蒸気タービン５０発電機
５１酸化用ブロア５２液受け
５３吸収液液面５４酸化用ブロア DESCRIPTION OF SYMBOLS 1 Exhaust gas 2 Outlet exhaust gas 3 Seawater desulfurization apparatus 4,7 Spray nozzle 5 Spray pump 6 Absorbing liquid (seawater)
8,35 Mist eliminator 9 Oxidizing gas supply unit 10 Stirrer 11 Absorbing liquid reservoir 12 Seawater 13 Boiler 16 Dust collector 17 Drainage 20 Iron 21 Absorbing liquid reservoir 25 Coal 26 Desulfurization absorber 27 Oxidizing gas 29 Chimney 36 For spray Pump 38 Tank 39 Pump 42 Condenser 43 Oxidation pit 44 Gas-gas heater 45 Seawater supply pump 46 Dust collector recovery ash 47 Iron separator 48 Press scrubber 49 Steam turbine 50 Generator 51 Oxidizing blower 52 Liquid receiver 53 Absorbed liquid Surface 54 Blower for oxidation

Claims

In a seawater desulfurization device having a desulfurization absorption part that is disposed in an exhaust gas flow path discharged from a combustion device and that contacts with sprayed seawater, and an absorption liquid reservoir that stores seawater that has absorbed sulfur in the exhaust gas,
An oxidation catalyst supply means is provided for supplying an oxidation catalyst for sulfurous acid to seawater supplied to the seawater desulfurization device, seawater discharged from the seawater desulfurization device, or seawater in the absorption liquid reservoir of the seawater desulfurization device. Seawater desulfurization equipment.

The seawater desulfurization device according to claim 1, wherein a press clubber for removing dust in the exhaust gas is provided on the upstream side of the seawater desulfurization device.

The oxidation catalyst supply means is an oxidation catalyst supply means previously immersed in the absorption liquid reservoir of the seawater desulfurization apparatus, or an oxidation catalyst supply means immersed in an absorption liquid in an absorption liquid receiver provided in the desulfurization absorption section. The seawater desulfurization apparatus according to claim 1.

A dust collector is disposed in the exhaust gas flow path on the upstream side of the seawater desulfurization device, an iron separation device is provided for recovering iron from the recovered ash recovered by the dust collector, and the iron catalyst is provided in the oxidation catalyst supply means. The seawater desulfurization apparatus according to claim 1, further comprising a configuration for supplying the obtained iron content.

The exhaust gas from the combustion device is introduced into the desulfurization device and brought into contact with the sprayed seawater, and the seawater that has absorbed the sulfur content in the exhaust gas is temporarily stored, and the temporarily stored seawater is again used as the exhaust gas. In the seawater desulfurization method to be contacted,
A seawater desulfurization method comprising supplying an oxidation catalyst for sulfurous acid to seawater for use in seawater desulfurization or seawater after the seawater desulfurization.

The exhaust gas from the combustion device is introduced into the press scrubber and brought into contact with the sprayed seawater. After removing the dust in the exhaust gas in advance, the exhaust gas from which the dust has been removed is introduced into the desulfurization device and brought into contact with the sprayed seawater. 6. The seawater desulfurization method according to claim 5, wherein the seawater that has absorbed the sulfur content is temporarily stored, and the temporarily stored seawater is brought into contact with the exhaust gas again.

The seawater desulfurization method according to claim 5, wherein the oxidation catalyst is iron or iron ions.

8. The seawater desulfurization method according to claim 7, wherein the iron ions are generated by contact between iron and seawater after desulfurization temporarily stored in a desulfurization apparatus.

6. The seawater desulfurization method according to claim 5, wherein the iron and the iron ions are used by separating the iron in the ash obtained by collecting the ash from the exhaust gas discharged from the combustion device with a dust collector.