200848148 九、發明說明 【發明所屬之技術領域】 本發明關於適用於煤炭焚燒、原油焚燒及重油焚燒等 的發電廠之排煙脫硫裝置，特別關於使用海水法進行脫硫 之排煙脫硫裝置。 【先前技術】 以往，在以煤炭或原油等爲燃料之發電廠，由鍋爐所 排出的燃燒排廢氣（以下稱爲鍋爐排廢氣），在除去含於 鍋爐排廢氣中之二氧化硫（so2)等的硫氧化物（sox)後 再釋放至大氣中。作爲實施這樣的脫硫處理的排煙脫硫裝 置之脫硫方式，石灰石石膏法、噴霧乾燥法及海水法爲眾 所皆知。 在這些方法中，採用海水法的排煙脫硫裝置（以下稱 爲海水脫硫裝置）是使用海水作爲吸收劑之脫硫方式。在 此方式，藉由對將例如大致呈圓筒的圓筒狀做成縱向配置 之脫硫塔（吸收塔）的內部，供給海水及鍋爐排廢氣，藉 此以海水作爲吸收液，產生濕式基座的氣液接觸，除去硫 氧化物。 在上述的海水脫硫裝置，通常的情況，在脫硫塔內作 爲吸收劑所使用過後的使用過海水流經水路（Sea Water Treatment System ; SWTS )排出至周邊海域。再者，對流 經水路內的使用過海水，實施例如脫碳酸（曝氣）等的處 理。 -5- 200848148 在此，針對以往的海水脫硫裝置，使用圖4簡單地說 明其一例。 圖不的海水脫硫裝置1，一方的海水由脫硫塔2的上 部供給並自然落下，與在由脫硫塔2的下部供給而上升的 鍋爐排廢氣之間產生氣液接觸。海水與鍋爐排廢氣之氣液 接觸是藉由將以預定的間隔呈複數段配置於脫硫塔2內的 上下方向之多孔板架3作爲濕式基座，使海水及鍋爐排廢 氣通過穿設於多孔板架3之多數個孔4來達到的。 再者，圖中的符號5爲海水供給管，6爲使脫硫後的 海水流出之使用過海水出口，7爲鍋爐排廢氣供給口，8 爲使脫硫後的鍋爐排廢氣流出之鍋爐排廢氣排氣口。、（ 參照例如專利文獻1、2 )。 在這樣的海水脫硫裝置1，會有藉由將脫硫塔2配置 於水路（SWTS ) 9的上方，將脫硫後的使用過海水由開口 於脫硫塔2的下端之使用過海水出口 6直接落下至水路9 內，進行排水之情況。即，藉由將流動於水路9內的稀釋 用海水、與由脫硫塔2落下並匯集之使用過海水混合，來 將使用過海水予以稀釋並排出。 又，在供使用過海水流動之水路9，爲了防止鍋爐排 廢氣由脫硫塔2流入，設置有延伸至進入水中的位置之氣 體封印用隔離壁1 〇。因此’被供給至脫硫塔2的鍋爐排廢 氣受到隔離壁1 〇與水面所封印，故，不會漏出至形成在 水路9的水面上之空間。 〔專利文獻丨〕日本特開平11-290643號公報 200848148 〔專利文獻2〕日本特開200 1 - 1 293 52號公報 【發明內容】 〔發明所欲解決之課題〕 然而，在上述海水脫硫裝置1，對流動於水路9內的 使用過海水，在排出至周邊海域前，實施利用曝氣之脫碳 酸處理。在此脫碳酸處理，當稀釋用的海水與使用過海水 未充分混合時，則會產生脫碳酸性能降低的問題。即，因 利用稀釋用海水進行使用過海水的混合、稀釋不充分，造 成在濃度上產生不均的話，則使用過稀釋海水流經+/進行 排水爲只之間所進行的脫碳酸處理之性能會降低，因此並 不理想。特別是流經水路9之稀釋用海水，由於在脫硫塔 2的正下方之水面附近（圖4中所示的區域A )，受到氣 體封印用而設置的隔離壁1 〇之影響，流動容易被遮斷’ 故，容易產生使用過稀釋海水的混合不良。 本發明是有鑑於上述情事而開發完成之發明’目的在 於針對使用海水法之排煙脫硫裝置，藉由促進使用過海水 與稀釋用海水之混合、稀釋，能夠在對使用過稀釋海水進 行脫碳酸處理之際，防止或抑制脫碳酸性能降低。 〔用以解決課題之手段〕 本發明爲了解決上述課題，而採用以下的手段。 本發明之排煙脫硫裝置，是使脫硫後的使用過海水落 下至流動於水路內的稀釋用海水，將受到與前述稀釋用海 -7 - 200848148 水之混合所稀釋的使用過稀釋海水在流動於前述水路內期 間進行脫碳酸處理之排煙脫硫裝置’其特徵爲：在前述水 路內，設置有用來促進前述使用過海水與前述稀釋用海水 的混合之混合促進手段。 若根據這樣之排煙脫硫裝置的話，因在水路內設有用 來促進使用過海水與稀釋用海水的混合之混合促進手段， 所以，可消除使用過海水與稀釋用海水之混合不良，促進 混合、稀釋。 在此情況，作爲理想的混合促進手段，具有：擾亂海 水的流動之靜態攪拌器等的紊亂產生裝置、由水路底面產 生細微氣泡之曝氣噴嘴、或紊亂產生裝置及曝氣噴嘴之組 合等。 〔發明效果〕 若根據上述本發明的話，因藉由在水路內設有用來促 進使用過海水與稀釋用海水的混合之混合促進手段，能夠 藉由促進混合、稀釋，消除使用過海水與稀釋用海水之混 合不良，所以，可獲得在流動於水路內期間所進行的使用 過稀釋海水的脫碳酸處理性能之顯著效果。 【實施方式】 以下’根據圖面’說明關於本發明之排煙脫硫裝置的 一實施形態。 在圖1所示的第1實施形態，顯示採用使用海水作爲 -8- 200848148 吸收劑之被稱爲海水法的脫硫方式之排煙脫硫裝置（以下 稱爲海水脫硫裝置）1。 此海水脫硫裝置1藉由對大致呈圓筒狀的脫硫塔2供 給鍋爐排廢氣及海水，使由上方自然落下之作爲吸收劑的 海水與由下方上生的鍋爐排廢氣在成爲濕式基座之多孔板 架3進行氣液接觸而脫硫。 在脫硫塔2的內部，複數段（在圖示例爲3段）的多 孔板架3在上下方向隔著間隔，平行地設置著。在各多孔 板架3，穿設有成爲鍋爐排廢氣及海水的通路之多數個孔 4 〇 成爲吸收劑之海水是經由海水供給管5，導入至脫硫 塔2的上部。此海水由大致均等地配置於脫硫塔2內的上 部平面之多數個海水噴嘴5 a，朝配置於下方的多孔板架3 流出。再者，在脫硫塔2的底面部，開口有使用過海水出 口 6，該出口是將通過了多孔板架3之脫硫後的使用過海 水直接落下至後數的水路（Sea Water Treatment System; SWTS ) 9。 另外，鍋爐排廢氣是由連通於較多孔板架3更下方的 鍋爐排廢氣供給口 7供給至脫硫塔2的內部，通過多孔板 架3後，由開口於脫硫塔2的上部之鍋爐排廢氣排氣口 8 排出。 即，由上方自然落下的海水與由下方上升的鍋爐排廢 氣在通過穿設於各段的多孔板架3的孔4之際會氣液接觸 ，藉由海水吸收鍋爐排廢氣中之硫氧化物，來進行脫硫。 -9- 200848148 上述脫硫塔2 ’是將使用過海水出口 6連通於導入稀 釋用海水並加以流通之水路9的上部開口來加以配置。此 水路9是將稀釋用海水導入並加以流動，並且將由2的+/ 落下並匯集的使用過海水加以稀釋，進一步對稀釋後的使 用過稀釋海水實施脫碳酸處理後予以排放之流路，通常採 用暗渠。稀釋用海水與使用過海水匯集混合之使用過稀釋 海水被導入至水路9，再排出至周邊海域，但在流經水路 9的途中貫施利用曝氣之脫酸處理。 又，在將脫硫塔2設置於水路9之開口部的下方，至 稀釋用海水所流動的水面更低的位置即進入至海水中的位 置爲止，設置有氣體封印用隔離壁1 0。此+ 1 0以包圍使用 過海水出口 6的開口部外周之方式形成，所以，由鍋爐排 廢氣供給口 7供給至脫硫塔2之鍋爐排廢氣會受到隔離壁 1 〇與水面所封印，防止流入至形成於水路9的水面上之空 間內。 又，在水路9的內部，設有擾亂稀釋用海水的流動之 紊亂產生器20，其作爲用來促進使用過海水與稀釋用海水 的混合之混合促進手段。 如圖1所示的紊亂產生器20是在流動於水路9內之 稀釋用海水的流動方向，設置於較脫硫塔2的設置位置更 上游側。作爲此紊亂產生器20，可使用例如靜待混合器這 種，攪拌稀釋用海水的流動等，形成漩渦般之紊亂者。但 ，紊亂產生器20不限於上述靜態混合器，亦可採用例如 配置於隔離壁1 〇的下方，供稀釋用海水通過之板狀或籃 -10- 200848148 子狀之網構件。再者，紊亂產生器20的設置位置，因承 受脫碳酸處理的使用過稀釋海水可充分被混合的話即可， 所以，成爲較在水路9內進行脫碳酸處理的位置更上游側 ，理想爲脫硫塔2的附近位置。 藉由設置這樣的紊亂產生器20，在通過水路9後導入 至脫硫塔2的下方之稀釋用海水，藉由紊亂產生器2 0的 作用，產生如途中的箭號a所示的漩渦等之紊亂。因此， 由脫硫塔2的使用過海水出口 6直接落下而與稀釋用海水 流匯集之使用過海水會被漩渦等的紊亂所攪拌，而促進了 混合。 因此，流經於水路9之使用過稀釋海水被充分地攪拌 、混合，在使用過海水的濃度大致均等化之狀態下流動， 承受利用曝氣之脫碳酸處理，因此，可提升水路9 ( SWTS )的脫碳酸性能。 接著，參照圖2說明本發明的第2實施形態。再者 ，針對與上述第1實施形態相同的部分賦予相同的符號， 並省略其詳細說明。 在此實施形態，促進使用過海水與稀釋用海水之混合 促進手段不同，在水路9的底面設置用來產生細微氣泡b 之曝氣噴嘴3 0來代替上述紊亂產生器20。在圖示例，曝 氣噴嘴3 0配置於脫硫塔2的下方，於由使用過海水出口 6 所流下的使用過海水與稀釋用海水匯集的區域’產生細微 氣泡b。 因此，流動於水路9的使用過稀釋海水被充分地攪拌 -11- 200848148 、混合，在使用過海水的濃度大致均等化之狀態下流動， 承受利用曝氣之脫碳酸處理，因此，可提升水路9 ( SWTS )的脫碳酸性能。 接著，參照圖3說明本發明的第3實施形態。再者， 針對與上述實施形態相同的部分賦予相同的符號，並省略 其詳細說明。 在此實施形態，並用上述紊亂產生器20與曝氣噴嘴 3 0，作爲用來促進使用過海水與稀釋用海水之混合的混合 促進手段。即，藉由紊亂產生器20產生漩渦等的紊亂， 並且由曝氣噴嘴3 0產生細微氣泡b，藉此，流動於水路9 之使用過稀釋海水進一步被充分地攪拌、混合。因此，使 用過稀釋海水在使用過海水的濃度更進一步均等化的狀態 下流動，承受利用曝氣之脫碳酸處理，因此，可提升水路 9 ( SWTS )的脫碳酸性能。 如此，若根據上述本發明的話，因在水路9內設置有 用來促進使用過海水與稀釋用海水之混合的混合促進手段 ，所以，藉由促進混合、稀釋，可消除使用過海水與稀釋 用海水之混合不良。因此，可提升在流動於水路9內的期 間所進行的使用過稀釋海水的脫碳酸處理，故，能夠減低 對排放使用過稀釋海水的周邊海域之環境的影響。 再者，本發明不限於上述實施形態，在不超出本發明 的技術思想範圍內，可適宜地進行各種變更。 【圖式簡單說明】 -12- 200848148 圖1是顯示本發明之排煙脫硫裝置的第1實施形態的 構成圖。 圖2是顯示本發明之排煙脫硫裝置的第2實施形態的 構成圖。 圖3是顯示本發明之排煙脫硫裝置的第3實施形態的 構成圖。 圖4是顯示排煙脫硫裝置之以往例的構成圖。 【主要元件符號說明】 1 :排煙脫硫裝置（海水脫硫裝置） 2 :脫硫塔 3 :多孔板架 5 =海水供給管 6 =使用過海水出口 7 :鍋爐排廢氣供給口 8 :鍋爐排廢氣排氣口 9 :水路（S WTS ) 20 :紊亂產生器 3 0 :曝氣噴嘴（混合促進手段） -13-200848148 IX. Description of the invention [Technical field to which the invention pertains] The present invention relates to a flue gas desulfurization device for a power plant for coal incineration, crude oil incineration, and heavy oil incineration, and more particularly to a flue gas desulfurization device for desulfurization using a seawater method . [Prior Art] In the power plant that uses coal or crude oil as fuel, the combustion exhaust gas (hereinafter referred to as boiler exhaust gas) discharged from the boiler removes sulfur dioxide (so2) contained in the exhaust gas of the boiler. Sulfur oxides (sox) are then released into the atmosphere. As a desulfurization method of a flue gas desulfurization apparatus for carrying out such desulfurization treatment, a limestone gypsum method, a spray drying method, and a seawater method are well known. Among these methods, a flue gas desulfurization apparatus using seawater method (hereinafter referred to as a seawater desulfurization apparatus) is a desulfurization method using seawater as an absorbent. In this way, seawater and boiler exhaust gas are supplied to the inside of a desulfurization tower (absorption tower) which is disposed in a longitudinal direction, for example, a substantially cylindrical shape, whereby seawater is used as an absorption liquid to generate a wet type. The gas-liquid contact of the susceptor removes sulfur oxides. In the above-described seawater desulfurization apparatus, in general, the used seawater used as an absorbent in the desulfurization tower is discharged to the surrounding sea area by a sea water treatment system (SWTS). Further, the seawater used in the water passage is subjected to treatment such as decarbonation (aeration). -5- 200848148 Here, an example of the conventional seawater desulfurization apparatus will be briefly described with reference to Fig. 4 . In the seawater desulfurization apparatus 1 of the drawing, one seawater is supplied from the upper portion of the desulfurization tower 2 and naturally falls, and gas-liquid contact occurs between the exhaust gas of the boiler which is supplied by the lower portion of the desulfurization tower 2 and rises. The gas-liquid contact between the seawater and the exhaust gas of the boiler is performed by passing the porous plate holder 3 disposed in the upper and lower directions in the desulfurization tower 2 at a predetermined interval as a wet base, and the seawater and the boiler exhaust gas are passed through. This is achieved by a plurality of holes 4 of the perforated plate holder 3. In addition, the symbol 5 in the figure is a seawater supply pipe, 6 is a seawater outlet for discharging seawater after desulfurization, 7 is a boiler exhaust gas supply port, and 8 is a boiler row for exhausting the boiler exhaust gas after desulfurization. Exhaust gas exhaust port. (See, for example, Patent Documents 1, 2). In such a seawater desulfurization apparatus 1, the desulfurization tower 2 is disposed above the waterway (SWTS) 9, and the used seawater after desulfurization is used to pass through the seawater outlet opening to the lower end of the desulfurization tower 2. 6 Drop directly into the waterway 9 for drainage. In other words, the seawater for dilution flowing in the water passage 9 is mixed with the used seawater dropped and collected by the desulfurization tower 2, and the used seawater is diluted and discharged. Further, in the water passage 9 through which the seawater has flowed, in order to prevent the boiler exhaust gas from flowing in from the desulfurization tower 2, a gas seal partition wall 1 that extends to a position entering the water is provided. Therefore, the waste gas discharged from the boiler supplied to the desulfurization tower 2 is sealed by the partition wall 1 and the water surface, so that it does not leak into the space formed on the water surface of the water path 9. [Patent Document 2] Japanese Laid-Open Patent Publication No. Hei No. H11-290643 (Patent Document 2) Japanese Patent Application Laid-Open No. Hei No. Hei No. Hei. 1. The used seawater flowing in the waterway 9 is subjected to decarbonation treatment by aeration before being discharged to the surrounding sea area. In the decarbonation treatment, when the seawater for dilution is not sufficiently mixed with the used seawater, there is a problem that the decarbonation performance is lowered. In other words, if the mixing and dilution of the used seawater by the seawater for dilution is insufficient, and the concentration is uneven, the performance of the decarbonation treatment by using the diluted seawater through the +/ drainage is performed. Will be lower, so it is not ideal. In particular, the seawater for dilution flowing through the water passage 9 is easily affected by the partition wall 1 provided by the gas seal due to the vicinity of the water surface directly below the desulfurization tower 2 (the area A shown in Fig. 4). It is blocked, so it is easy to produce poor mixing of used diluted seawater. The present invention has been developed in view of the above circumstances. The present invention is directed to a flue gas desulfurization apparatus using a seawater method, which can be used to remove excess diluted seawater by promoting mixing and dilution of seawater used for use and seawater for dilution. At the time of carbonation treatment, the decarbonation performance is prevented or suppressed from being lowered. [Means for Solving the Problem] In order to solve the above problems, the present invention employs the following means. The flue gas desulfurization device of the present invention is a diluted seawater which is diluted with seawater after desulfurization and flows into a waterway, and is diluted with seawater diluted with the aforementioned dilution sea-7 - 200848148 water. A flue gas desulfurization apparatus that performs decarbonation treatment while flowing in the water passage is characterized in that a mixing promotion means for promoting mixing of the seawater used and the seawater for dilution is provided in the water passage. According to such a flue gas desulfurization apparatus, since the mixing means for promoting the mixing of the seawater used and the seawater for dilution is provided in the waterway, the mixing failure of the seawater used for use and the seawater for dilution can be eliminated, and the mixing can be promoted. ,dilution. In this case, as an ideal means for promoting the mixing, there are a disorder generating device such as a static agitator that disturbs the flow of sea water, an aeration nozzle that generates fine bubbles from the bottom surface of the water passage, or a combination of a disorder generating device and an aeration nozzle. [Effect of the Invention] According to the present invention, it is possible to eliminate the use of seawater and dilution by promoting mixing and dilution by providing a mixing promoting means for promoting mixing of the used seawater and the seawater for dilution in the waterway. Since the seawater is poorly mixed, a remarkable effect of the decarbonation treatment performance using the diluted seawater during the flow in the waterway can be obtained. [Embodiment] Hereinafter, an embodiment of the flue gas desulfurization apparatus according to the present invention will be described with reference to the drawings. In the first embodiment shown in Fig. 1, a flue gas desulfurization apparatus (hereinafter referred to as seawater desulfurization apparatus) 1 which is a desulfurization method called seawater method using seawater as an absorbent of -8-200848148 is used. In the seawater desulfurization apparatus 1, the exhaust gas and the seawater are supplied to the boiler in the substantially cylindrical desulfurization tower 2, and the seawater as the absorbent which is naturally dropped from above and the exhaust gas discharged from the boiler below are wetted. The porous plate holder 3 of the susceptor is subjected to gas-liquid contact to desulfurize. Inside the desulfurization tower 2, a plurality of stages (three stages in the illustrated example) are arranged in parallel at intervals in the vertical direction. In each of the perforated racks 3, a plurality of holes through which the exhaust gas and the seawater of the boiler are bored are formed. The seawater which is an absorbent is introduced into the upper portion of the desulfurization tower 2 via the seawater supply pipe 5. This seawater flows out through a plurality of seawater nozzles 5a disposed substantially uniformly on the upper plane in the desulfurization tower 2, and flows out toward the perforated trays 3 disposed below. Further, in the bottom surface portion of the desulfurization tower 2, a seawater outlet 6 is used, which is a waterway that directly drops the used seawater that has passed through the desulfurization of the perforated tray 3 to the last number (Sea Water Treatment System) ; SWTS) 9. Further, the exhaust gas of the boiler is supplied to the inside of the desulfurization tower 2 by the boiler exhaust gas supply port 7 connected to the lower side of the relatively porous rack 3, and after passing through the perforated rack 3, the boiler is opened to the upper portion of the desulfurization tower 2. The exhaust gas exhaust port 8 is exhausted. That is, the seawater naturally falling from above and the exhaust gas of the boiler rising from the lower side are in gas-liquid contact while passing through the holes 4 of the perforated plate frame 3 penetrating each stage, and the seawater absorbs the sulfur oxides in the exhaust gas of the boiler. To carry out desulfurization. -9- 200848148 The above-described desulfurization tower 2' is disposed such that the used seawater outlet 6 communicates with the upper opening of the water passage 9 into which the seawater for dilution is introduced and flows. This waterway 9 is a flow path in which the seawater for dilution is introduced and flows, and the used seawater which has been dropped by +/ is collected and diluted, and the diluted diluted seawater is further subjected to decarbonation treatment, and then discharged. Use culverts. The diluted seawater is mixed with the used seawater and used to be diluted. The seawater is introduced into the waterway 9 and discharged to the surrounding sea area. However, the aerated deacidification treatment is applied while flowing through the waterway 9. Further, the desulfurization tower 2 is installed below the opening of the water passage 9, and the gas seal partition wall 10 is provided until the water surface where the dilution seawater flows is at a position lower than the water surface. Since the +10 is formed so as to surround the outer periphery of the opening portion through which the seawater outlet 6 is used, the exhaust gas of the boiler supplied to the desulfurization tower 2 from the boiler exhaust gas supply port 7 is sealed by the partition wall 1 and the water surface to prevent it from being sealed. It flows into the space formed on the water surface of the waterway 9. Further, inside the water path 9, a disturbance generator 20 for disturbing the flow of the seawater for dilution is provided as a mixing promotion means for promoting the mixing of the seawater used for use and the seawater for dilution. The disturbance generator 20 shown in Fig. 1 is disposed on the upstream side of the installation position of the desulfurization tower 2 in the flow direction of the seawater for dilution flowing in the water passage 9. As the disturbance generator 20, for example, a static mixer can be used, and the flow of the seawater for dilution can be stirred to form a vortex-like disorder. However, the disturbance generator 20 is not limited to the above-described static mixer, and may be, for example, a mesh member which is disposed below the partition wall 1 , for the dilution seawater to pass through, or a basket -10- 200848148. In addition, since the installation position of the disturbance generator 20 can be sufficiently mixed by the use of the diluted seawater subjected to the decarbonation treatment, it is more upstream than the position where the decarbonation treatment is performed in the water passage 9, and it is preferable to take off. The location near the sulfur tower 2. By providing such a disturbance generator 20, the seawater for dilution introduced into the lower portion of the desulfurization tower 2 after passing through the water passage 9 generates a vortex as indicated by the arrow a in the middle by the action of the disturbance generator 20. Disorder. Therefore, the used seawater which has been directly dropped by the seawater outlet 6 of the desulfurization tower 2 and collected by the seawater for dilution is stirred by a disorder such as a vortex, thereby promoting mixing. Therefore, the used diluted seawater flowing through the water passage 9 is sufficiently stirred and mixed, flows in a state where the concentration of the used seawater is substantially equalized, and is subjected to decarbonation treatment by aeration, so that the water passage 9 can be lifted (SWTS) Decarbonation performance. Next, a second embodiment of the present invention will be described with reference to Fig. 2 . The same portions as those in the first embodiment are denoted by the same reference numerals, and the detailed description thereof will be omitted. In this embodiment, the aeration nozzle 30 for generating the fine bubbles b is provided on the bottom surface of the water path 9 instead of the above-described disturbance generator 20, in order to promote the mixing promotion means for using the seawater and the seawater for dilution. In the example of the drawing, the aeration nozzle 30 is disposed below the desulfurization tower 2, and generates fine bubbles b in a region where the used seawater and the dilution seawater flowed down through the seawater outlet 6 are collected. Therefore, the used diluted seawater flowing in the waterway 9 is sufficiently stirred -11-200848148, mixed, and flows in a state where the concentration of the used seawater is substantially equalized, and is subjected to decarbonation treatment by aeration, thereby improving the waterway Decarbonation performance of 9 (SWTS). Next, a third embodiment of the present invention will be described with reference to Fig. 3 . The same portions as those of the above-described embodiments are denoted by the same reference numerals, and their detailed descriptions are omitted. In this embodiment, the disturbance generator 20 and the aeration nozzle 30 are used in combination as a mixing promoting means for promoting the mixing of the seawater used and the seawater for dilution. In other words, the disturbance generator 20 generates a disorder such as a vortex, and the fine bubbles b are generated by the aeration nozzle 30, whereby the used diluted seawater flowing through the water passage 9 is further sufficiently stirred and mixed. Therefore, the used diluted seawater flows in a state where the concentration of the used seawater is further equalized, and is subjected to decarbonation treatment by aeration, thereby improving the decarbonation performance of the water passage 9 (SWTS). As described above, according to the present invention, since the mixing means for promoting the mixing of the used seawater and the seawater for dilution is provided in the water passage 9, the seawater used for dilution and the seawater for dilution can be eliminated by promoting mixing and dilution. Poor mixing. Therefore, the decarbonation treatment using the diluted seawater during the flow in the water passage 9 can be improved, so that the influence on the environment of the surrounding sea area where the diluted seawater is used can be reduced. In addition, the present invention is not limited to the above-described embodiments, and various modifications can be appropriately made without departing from the scope of the technical idea of the present invention. [Brief Description of the Drawings] -12- 200848148 Fig. 1 is a configuration diagram showing a first embodiment of the flue gas desulfurization apparatus of the present invention. Fig. 2 is a view showing the configuration of a second embodiment of the flue gas desulfurization apparatus of the present invention. Fig. 3 is a view showing the configuration of a third embodiment of the flue gas desulfurization apparatus of the present invention. Fig. 4 is a configuration diagram showing a conventional example of a flue gas desulfurization apparatus. [Main component symbol description] 1 : Flue gas desulfurization device (seawater desulfurization device) 2 : Desulfurization tower 3 : Porous plate rack 5 = Seawater supply pipe 6 = Used seawater outlet 7 : Boiler exhaust gas supply port 8 : Boiler Exhaust gas exhaust port 9: Water path (S WTS ) 20 : Disturbance generator 3 0 : Aeration nozzle (mixing promotion means) -13-