JP3333031B2 - Wet exhaust gas desulfurization method - Google Patents
Wet exhaust gas desulfurization methodInfo
- Publication number
- JP3333031B2 JP3333031B2 JP00540694A JP540694A JP3333031B2 JP 3333031 B2 JP3333031 B2 JP 3333031B2 JP 00540694 A JP00540694 A JP 00540694A JP 540694 A JP540694 A JP 540694A JP 3333031 B2 JP3333031 B2 JP 3333031B2
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- absorption tower
- spray
- spray header
- absorption
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000006477 desulfuration reaction Methods 0.000 title claims description 14
- 230000023556 desulfurization Effects 0.000 title claims description 14
- 238000000034 method Methods 0.000 title claims description 9
- 239000007921 spray Substances 0.000 claims description 100
- 238000010521 absorption reaction Methods 0.000 claims description 88
- 239000007788 liquid Substances 0.000 claims description 49
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 claims description 28
- 229910052815 sulfur oxide Inorganic materials 0.000 claims description 22
- 239000003595 mist Substances 0.000 claims description 19
- TXKMVPPZCYKFAC-UHFFFAOYSA-N disulfur monoxide Inorganic materials O=S=S TXKMVPPZCYKFAC-UHFFFAOYSA-N 0.000 claims description 6
- 238000002347 injection Methods 0.000 claims 1
- 239000007924 injection Substances 0.000 claims 1
- 239000007789 gas Substances 0.000 description 64
- 239000000428 dust Substances 0.000 description 26
- 239000010440 gypsum Substances 0.000 description 11
- 229910052602 gypsum Inorganic materials 0.000 description 11
- 235000019738 Limestone Nutrition 0.000 description 10
- 239000006028 limestone Substances 0.000 description 10
- 230000000694 effects Effects 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 230000002745 absorbent Effects 0.000 description 4
- 239000002250 absorbent Substances 0.000 description 4
- 239000006096 absorbing agent Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 239000012535 impurity Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
Landscapes
- Treating Waste Gases (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、湿式排ガス脱硫方法に
係り、特に排ガス中の硫黄酸化物および煤塵を低減する
のに好適な高効率の湿式排ガス脱硫方法に関する。The present invention relates to a wet exhaust gas desulfurization method , and more particularly to a highly efficient wet exhaust gas desulfurization method suitable for reducing sulfur oxides and dust in exhaust gas.
【０００２】[0002]
【従来の技術】大気汚染防止のため、排ガス中の硫黄酸
化物の除去装置として、湿式石灰石−石膏脱硫装置が広
く実用化されている。この湿式石灰石−石膏脱硫装置の
従来技術を図３に示す。火力発電所等から発生した、硫
黄酸化物および煤塵を含む排ガス１は排ガス脱硫装置の
吸収塔２に導かれる。吸収塔２内では多数のスプレノズ
ルを備えたスプレヘッダ（３、１７、１８、１９）が少
なくとも２段以上設置されており、下向きに取付けられ
たスプレノズル４から微細な液滴として噴霧される吸収
液と、排ガス１を接触させることで、排ガス中の硫黄酸
化物は吸収液滴の表面で化学的に吸収され、煤塵は液滴
との衝突により物理的に除去される。排ガス流れに同伴
する微小な液滴は最上段スプレヘッダ１９の上部に設置
されたミストエリミネータ５で除去され、浄化された排
ガス６は必要により吸収塔後流側に設置される図示して
いない再加熱設備により昇温されて、煙突より排出され
る。ノズル４から噴霧された大部分の液滴は硫黄酸化物
を吸収したのち吸収塔下部に設けられた吸収塔循環タン
ク７中に落下する。2. Description of the Related Art In order to prevent air pollution, wet limestone-gypsum desulfurization apparatuses are widely used as apparatuses for removing sulfur oxides in exhaust gas. FIG. 3 shows a conventional technique of this wet limestone-gypsum desulfurization apparatus. Exhaust gas 1 containing sulfur oxides and dust generated from a thermal power plant or the like is led to an absorption tower 2 of an exhaust gas desulfurization device. In the absorption tower 2, at least two or more spray headers (3, 17, 18, and 19) having a large number of spray nozzles are installed, and an absorption liquid sprayed as fine droplets from a spray nozzle 4 mounted downward is provided. By contacting the exhaust gas 1, the sulfur oxides in the exhaust gas are chemically absorbed on the surface of the absorbing droplet, and the dust is physically removed by collision with the droplet. The fine droplets accompanying the exhaust gas flow are removed by the mist eliminator 5 installed on the upper part of the uppermost spray header 19, and the purified exhaust gas 6 is reheated (not shown) installed on the downstream side of the absorption tower if necessary. The temperature is raised by the equipment and discharged from the chimney. Most of the droplets sprayed from the nozzle 4 absorb the sulfur oxide and then fall into the absorption tower circulation tank 7 provided at the lower part of the absorption tower.
【０００３】吸収液に吸収された硫黄酸化物（ＳＯ2 ）
は、吸収液中に含まれる石灰石（ＣａＣＯ3 ）と反応
し、さらに吸収塔循環タンク７に供給される空気８によ
って酸化され石膏（ＣａＳＯ4 ・２Ｈ2 Ｏ）となる。こ
の一連の反応は下記式によって表わされる。[0003] Sulfur oxide (SO 2 ) absorbed in the absorbing solution
Reacts with limestone (CaCO 3 ) contained in the absorption liquid, and is further oxidized by the air 8 supplied to the absorption tower circulation tank 7 to form gypsum (CaSO 4 .2H 2 O). This series of reactions is represented by the following formula.
【０００４】[0004]
【化１】ＳＯ2 ＋２Ｈ2 Ｏ＋ＣａＣＯ3 ＋1/2Ｏ2 →Ｃ
ａＳＯ4 ・２Ｈ2 Ｏ＋ＣＯ2 また、除去された煤塵は吸収液とともに吸収塔循環タン
ク７に落下する。一方吸収剤である石灰石９は、石灰石
供給設備１０で石灰石スラリとして貯えられ石灰石スラ
リポンプ１１により、吸収塔循環タンク７へ供給され
る。また、吸収塔内で生成した石膏を回収するため、吸
収塔循環タンク７内の吸収液の一部を抜出しポンプ１２
にて石膏脱水設備１３に送液し、吸収液中に含まれてい
る石膏および煤塵を固形物１４として回収する。石膏お
よび煤塵の脱水液は、系内に不純物が濃縮するのを防ぐ
ため一部を排水ライン１５より系外に排出し、残りの液
は石灰石供給設備１０にて石灰石スラリ製造用補給水と
して使用され、残りは吸収塔へ脱水液戻りライン１６を
経て送液される。Embedded image SO 2 + 2H 2 O + CaCO 3 + 1 / 2O 2 → C
aSO 4 .2H 2 O + CO 2 The removed dust falls into the absorption tower circulation tank 7 together with the absorbing liquid. On the other hand, limestone 9 as an absorbent is stored as limestone slurry in a limestone supply facility 10 and supplied to an absorption tower circulation tank 7 by a limestone slurry pump 11. In order to collect the gypsum generated in the absorption tower, a part of the absorption liquid in the absorption tower circulation tank 7 is withdrawn and a pump 12 is used.
And the gypsum and dust contained in the absorbent are collected as solids 14. Part of the gypsum and dust dewatering solution is discharged out of the system through the drainage line 15 to prevent the concentration of impurities in the system, and the remaining liquid is used as makeup water for limestone slurry production in the limestone supply facility 10. The remainder is sent to the absorption tower via the dehydrated liquid return line 16.
【０００５】吸収塔内ではタンク７内の吸収液が循環ポ
ンプ２３によりスプレヘッダに送られ、前述のスプレノ
ズル４より噴霧されているが、循環噴霧される吸収液量
は排ガス量、排ガス中の硫黄酸化物濃度、および要求脱
硫率によって決定されている。一方、スプレヘッダ１段
当たりの流量は使用するスプレノズルの容量、スプレノ
ズル取付け間隔により決定されるため、通常はスプレヘ
ッダを３〜６段にする必要がある。すなわち、吸収液は
吸収塔内で各スプレヘッダ３、１７、１８、１９に分割
されて噴霧されている。ここでスプレノズル４から噴霧
される吸収液の噴霧状態を図４に示す。一般的にホロコ
ーンと呼ばれる円錐環状に吸収液は噴霧され、この噴霧
角度は大体８０〜１２０°となっている。スプレノズル
４から噴霧された吸収液２０は、スプレノズル４から噴
霧された直後は吸収液滴の密度が高く、スプレノズル４
から噴霧された後飛行距離が大きくなるほど液滴の密度
は小さくなる。そのため排ガス中の硫黄酸化物および煤
塵の除去効率はスプレノズル４から噴霧された直後の液
滴密度が高い部分で大きくなる。そのため、硫黄酸化物
および煤塵の除去効率を高めるためには吸収塔内の吸収
液の液滴密度を高めることが望ましいが、前述の従来技
術では吸収液を各スプレヘッダに分割して噴霧している
ため、各スプレヘッダから噴霧された吸収液の液滴密度
はどのスプレヘッダの部分もほぼ同じとなっていた。[0005] In the absorption tower, the absorption liquid in the tank 7 is sent to the spray header by the circulation pump 23 and sprayed from the spray nozzle 4. And the required desulfurization rate. On the other hand, since the flow rate per spray header is determined by the capacity of the spray nozzle to be used and the installation interval of the spray nozzle, usually, the spray header needs to have three to six stages. That is, the absorbing liquid is sprayed by being divided into the spray headers 3, 17, 18, and 19 in the absorbing tower. FIG. 4 shows a spray state of the absorbing liquid sprayed from the spray nozzle 4. The absorption liquid is sprayed in a conical ring generally called a hollow cone, and the spray angle is approximately 80 to 120 °. Immediately after being sprayed from the spray nozzle 4, the absorbing liquid 20 sprayed from the spray nozzle 4 has a high density of absorbing droplets,
The greater the flight distance after spraying from, the lower the density of the droplets. Therefore, the removal efficiency of sulfur oxides and dust in the exhaust gas increases at a portion where the droplet density is high immediately after being sprayed from the spray nozzle 4. Therefore, in order to increase the removal efficiency of sulfur oxides and dust, it is desirable to increase the droplet density of the absorbing liquid in the absorbing tower. However, in the above-described conventional technique, the absorbing liquid is divided into each spray header and sprayed. For this reason, the droplet density of the absorbing liquid sprayed from each spray header was almost the same in every spray header.
【０００６】また、吸収塔内の排ガス流速を高めること
により硫黄酸化物の吸収液への拡散、吸収速度を増加で
き、煤塵も吸収液への衝突速度が上昇するので除去効率
を向上できる。さらに、必要な吸収塔断面積が減少する
ため吸収塔径を小さくでき、設備費を低減することが可
能となるが、吸収塔上部に設置しているミストエリミネ
ータ５は限界流速が約３ｍ／ｓであり、それ以上となる
と、ミストエリミネータ５で捕集したミストが再飛散す
るので、吸収塔内のガス流速はミストエリミネータ５の
限界流速以下とする必要があった。従来の吸収塔内最後
流部に設けるミストエリミネータの構造の概要を図３の
右上方に示す。くの字状に折れ曲がった波板を上下方向
に所定間隔で多数並べて形成されており（横形）、処理
ガス中のミストは波板間を通過する間に慣性により波板
に付着し、このミストがある程度溜まると大きな液滴と
なって下方に落下するが、ガス流速が高すぎると（限界
流速３ｍ／ｓ）下方へ落下せずガスにあおられて上方に
液滴が飛散する。[0006] In addition, by increasing the flow rate of exhaust gas in the absorption tower, it is possible to increase the diffusion and absorption speed of sulfur oxides into the absorbing solution, and to improve the removal efficiency of dust as the collision speed with the absorbing solution increases. Furthermore, since the required absorption tower cross-sectional area is reduced, the diameter of the absorption tower can be reduced, and equipment costs can be reduced. However, the mist eliminator 5 installed above the absorption tower has a critical flow velocity of about 3 m / s. Above that, the mist collected by the mist eliminator 5 re-scatters, so that the gas flow rate in the absorption tower needs to be lower than the limit flow rate of the mist eliminator 5. An outline of the structure of the mist eliminator provided at the last stream in the conventional absorption tower is shown in the upper right of FIG. A large number of corrugated sheets bent in the shape of a letter are vertically arranged at predetermined intervals (horizontal shape), and the mist in the processing gas adheres to the corrugated sheet by inertia while passing between the corrugated sheets. When the gas accumulates to some extent, the droplets fall down as large droplets. However, if the gas flow velocity is too high (limit flow velocity 3 m / s), the droplets will not fall downward but will be scattered upward by the gas.
【０００７】図５は他の従来技術を示す説明図である。
図５においては、吸収塔２内にスプレヘッダ３、１７、
１８、１９が設けられ、各スプレヘッダに設けたスプレ
ノズル４より排ガス流れ方向に対し向流となる下向き方
向に吸収液が噴霧される。また、最上流段（図では最下
段）のスプレヘッダ３の下方には多孔板２１が設けられ
ている。この多孔板は吸収塔２内に塔側壁に設けた排ガ
ス入口から流入した排ガスが、できるだけ吸収塔水平断
面内を均一に上昇流過するように整流することを目的と
するものである。FIG. 5 is an explanatory view showing another conventional technique.
In FIG. 5, the spray headers 3, 17, and
18 and 19 are provided, and the absorbing liquid is sprayed downward from the spray nozzle 4 provided on each spray header in a countercurrent to the exhaust gas flow direction. Further, a perforated plate 21 is provided below the spray header 3 at the most upstream stage (the bottom stage in the figure). The purpose of this perforated plate is to rectify the exhaust gas flowing from the exhaust gas inlet provided on the side wall of the absorption tower 2 so as to flow as uniformly as possible in the horizontal section of the absorption tower.
【０００８】この多孔板２１にはスプレノズル４から噴
霧された吸収液滴が落下接触し多孔板を経て塔下部の吸
収塔循環タンクに滴下する際、吸収液中の石膏が多孔板
に析出し、多孔板開口部を閉塞せんとする傾向があり、
特に多孔板下面でその傾向が著しい。よって、これを防
止するため多孔板下部に上向き噴霧ノズル４′を有する
スプレヘッダ２２が設けられている。When the absorbing droplets sprayed from the spray nozzle 4 fall and contact the perforated plate 21 and drop into the absorption tower circulation tank at the bottom of the tower through the perforated plate, gypsum in the absorbing solution precipitates on the perforated plate. There is a tendency to block the opening of the perforated plate,
In particular, the tendency is remarkable on the lower surface of the perforated plate. Therefore, in order to prevent this, a spray header 22 having an upward spray nozzle 4 'is provided below the perforated plate.
【０００９】スプレヘッダ３と２２に設けたノズルから
は対向する方向に吸収液が噴霧されているが、多孔板２
１に隔てられているため吸収塔内での噴霧液滴密度を増
加させることはできなかった。The nozzles provided in the spray headers 3 and 22 spray the absorbing liquid in opposite directions.
1, it was not possible to increase the density of the spray droplets in the absorption tower.
【００１０】[0010]
【発明が解決しようとする課題】上記従来技術は、吸収
塔内で吸収液の液滴密度を高めて、硫黄酸化物および煤
塵の除去効率を高めることについて配慮がされておら
ず、排ガス中の硫黄酸化物量または煤塵量が多い場合に
は吸収塔で吸収液の循環噴霧量を増加させる必要がある
のでスプレヘッダの段数が増えるため、設備費および運
転費が増大する問題があった。また、ミストエリミネー
タの限界流速の制約から、吸収塔内のガス流速を増加で
きないため、処理ガス量が増えるほど吸収塔径は大きく
なり設備費が増大する問題があった。In the above prior art, no consideration is given to increasing the droplet density of the absorbing solution in the absorption tower to increase the efficiency of removing sulfur oxides and dust, and the prior art is not concerned with this. When the amount of sulfur oxides or dust is large, it is necessary to increase the amount of the circulating spray of the absorbing liquid in the absorption tower, so that the number of stages of the spray header is increased, so that there is a problem that the equipment cost and the operating cost increase. Further, since the gas flow velocity in the absorption tower cannot be increased due to the limitation of the limit flow velocity of the mist eliminator, there is a problem that the diameter of the absorption tower becomes larger and the equipment cost increases as the processing gas amount increases.
【００１１】本発明の目的は、吸収塔内に吸収液の液滴
密度が高い領域を形成することで、硫黄酸化物および煤
塵を高い効率で除去するとともに、吸収塔内のガス流速
を増加させて吸収塔径を縮小できる、経済的な排ガス脱
硫方法を提供することにある。An object of the present invention is to form a region having a high absorption liquid droplet density in an absorption tower, thereby removing sulfur oxides and dust with high efficiency and increasing the gas flow rate in the absorption tower. It can reduce the absorption tower diameter Te, economic exhaust gas removal
An object of the present invention is to provide a sulfurizing method .
【００１２】[0012]
【課題を解決するための手段】上記目的を達成するため
本願で特許請求される発明は以下のとおりである。 （１）竪型吸収塔内の下方から上方に排ガスを通過さ
せ、吸収塔内に配置された複数段のスプレヘッダに設け
たスプレノズルより吸収液を噴霧して排ガス中の硫黄酸
化物を吸収除去する湿式排ガス脱硫方法において、吸収
塔内の排ガス速度を３ｍ／ｓを超え７ｍ／ｓ以下とする
とともに、最下段のスプレヘッダのスプレノズルを上向
き噴射、次の上方段のスプレヘッダのスプレノズルを下
向き噴射とし、かつそれらより上段にもスプレヘッダを
設けてスプレノズルから噴射できるようにし、吸収塔出
口後流排ガスダクトに設けた縦型波板ミストエリミネー
タにより排ガス中のミストを除去し、かつ吸収塔内での
排ガスの硫黄酸化物処理量（負荷）が減少した場合に
は、上段のスプレヘッダから負荷に応じて吸収液の噴射
を停止することを特徴とする湿式排ガス脱硫方法。 The invention claimed in the present application to achieve the above object is as follows. (1) The exhaust gas is passed upward from below in the vertical absorption tower, and the absorption liquid is sprayed from spray nozzles provided in a plurality of spray headers arranged in the absorption tower to absorb and remove sulfur oxides in the exhaust gas. In the wet exhaust gas desulfurization method, the exhaust gas velocity in the absorption tower is more than 3 m / s and 7 m / s or less, the spray nozzle of the lowermost spray header is upwardly sprayed, the spray nozzle of the next upper spray header is downwardly sprayed, and Spray headers are provided above them so that they can be sprayed from the spray nozzles , and the
Vertical corrugated sheet mist eliminator installed in exhaust gas duct downstream of mouth
Removes the mist in the exhaust gas
When the sulfur oxide processing amount (load) of the exhaust gas decreases
Sprays the absorbing liquid from the upper spray header according to the load.
A wet exhaust gas desulfurization method, wherein the method is stopped.
【００１３】[0013]
【００１４】[0014]
【００１５】[0015]
【作用】吸収塔内で下方から１段目の上向きスプレノズ
ルと２段目の下向きスプレノズルによって吸収液の液滴
密度が高い領域を形成し、また吸収塔内のミストエリミ
ネータを省略することで、吸収塔内のガス流速を増加す
ることで排ガスと吸収液の接触効率を高められるので、
排ガス中の硫黄酸化物および煤塵の除去効率を高めるこ
とができる。In the absorption tower, a region where the droplet density of the absorbing liquid is high is formed by a first-stage upward spray nozzle and a second-stage downward spray nozzle from below, and the mist eliminator in the absorption tower is omitted. By increasing the gas flow velocity inside the tank, the contact efficiency between the exhaust gas and the absorbent can be increased,
The removal efficiency of sulfur oxides and dust in exhaust gas can be improved.
【００１６】さらに、下方から１段目のスプレヘッダの
上向きノズルと、下から２段目のスプレヘッダの下向き
ノズルのノズル中心がほぼ同一線上に向き合うようにす
ることにより、吸収塔内入口部に一層液滴密度の高い領
域を形成することができる。また、図１に示すように堅
型吸収塔側壁に設けた入口より排ガスが流入し、流動の
向きを上向きに偏向する場合ガス流は入口と反対側の側
壁に偏る傾向があるが、本発明では最下段に液滴密度の
高い領域を形成するので、この偏流を修正する効果があ
る。Further, by making the nozzle centers of the upward nozzles of the spray header of the first stage from the bottom and the downward nozzles of the spray header of the second stage from the bottom face substantially on the same line, the liquid is more concentrated at the inlet portion in the absorption tower. A region with a high droplet density can be formed. Also, as shown in FIG. 1, when exhaust gas flows in from the inlet provided on the side wall of the rigid absorber and deflects the flow direction upward, the gas flow tends to be biased toward the side wall opposite to the inlet. In this case, since a region having a high droplet density is formed at the lowermost stage, there is an effect of correcting this drift.
【００１７】[0017]
【実施例】本発明の実施例を図１に示す。硫黄酸化物お
よび煤塵を含む排ガス１は排ガス脱硫装置の吸収塔２内
に吸収塔排ガス入口１ａを経て導かれる。吸収塔内では
１段目（最下段）スプレヘッダ３にスプレノズル４が上
向きに取付けられており、２段目スプレヘッダ１７には
下向きにスプレノズル４が取付けられている。吸収塔内
に導かれた排ガスは、１段目スプレヘッダ３と２段目ス
プレヘッダ１７に取付けられたスプレノズル４から噴霧
された液滴密度の高い領域で、硫黄酸化物および煤塵が
効率よく除去され、さらに３、４段目のスプレヘッダ１
８、１９に取付けられたスプレノズル４から噴霧される
吸収液によって残りの硫黄酸化物および煤塵が除去され
る。３段目以降のスプレヘッダは排ガス中の硫黄酸化物
量に応じて必要な段数を設置すればよい。スプレ部を通
過し浄化された排ガスは微細な液滴（ミスト）を含んで
いるため、吸収塔出口ダクト５ａに設置されたミストエ
リミネータ５によりミストが除去される。FIG. 1 shows an embodiment of the present invention. Exhaust gas 1 containing sulfur oxides and dust is led into an absorption tower 2 of an exhaust gas desulfurization unit via an absorption tower exhaust gas inlet 1a. In the absorption tower, the spray nozzle 4 is attached to the first (lowest) spray header 3 upward, and the spray nozzle 4 is attached to the second spray header 17 downward. The exhaust gas guided into the absorption tower has a high density of droplets sprayed from the spray nozzles 4 attached to the first-stage spray header 3 and the second-stage spray header 17, and sulfur oxides and dust are efficiently removed. 3rd and 4th stage spray header 1
The remaining sulfur oxides and dust are removed by the absorbing liquid sprayed from the spray nozzles 4 attached to 8, 19. The required number of spray headers in the third and subsequent stages may be set according to the amount of sulfur oxides in the exhaust gas. Since the exhaust gas that has passed through the spray section and has been purified contains fine droplets (mist), mist is removed by the mist eliminator 5 installed in the absorption tower outlet duct 5a.
【００１８】水平の吸収塔出口ダクト５ａに設けるミス
トエリミネータ５の概要を図１の右上方部に示す。波板
は上下方向に縦形として設置されており、捕集したミス
トは液滴となって波板を伝わって下方に速やかに流れ落
ち底部に設けたホッパで回収される。そのため波板（折
れ板）に溜まる液量が少ないので、液膜がちぎれにく
く、ガス流速を従来の３ｍ／ｓを超えおよそ７ｍ／ｓ程
度まで上げて脱硫率を向上できる。The outline of the mist eliminator 5 provided in the horizontal absorption tower outlet duct 5a is shown in the upper right part of FIG. The corrugated sheet is installed vertically in the vertical direction, and the collected mist forms droplets, travels down the corrugated sheet, flows down quickly, and is collected by a hopper provided at the bottom. Therefore, the amount of liquid accumulated on the corrugated plate (folded plate) is small, so that the liquid film is hardly torn, and the gas flow rate can be increased from about 3 m / s to about 7 m / s to improve the desulfurization rate.
【００１９】吸収液中に吸収された硫黄酸化物は、吸収
液中の石灰石および吸収塔循環タンク７に供給される空
気８中の酸素と反応して石膏が生成される。吸収液中の
石膏および煤塵を回収するため、吸収液の一部が抜出し
ポンプ１２によって石膏回収設備１３へ送液され、吸収
液中の石膏および煤塵は固形物１４として回収され、脱
水液は系内に不純物が濃縮するのを防ぐため一部が排水
ライン１５から系外へ排出され、残りの脱水液はライン
１６を経て吸収塔に戻されるか、または石灰石供給設備
１０へ補給水として送液される。The sulfur oxides absorbed in the absorbing solution react with limestone in the absorbing solution and oxygen in the air 8 supplied to the absorption tower circulation tank 7 to produce gypsum. In order to collect gypsum and dust in the absorbing solution, a part of the absorbing solution is sent to a gypsum collecting facility 13 by a withdrawal pump 12, the gypsum and dust in the absorbing solution are collected as a solid matter 14, and the dehydrating solution is Part of the dewatered liquid is discharged out of the system from a drain line 15 to prevent impurities from being concentrated in the system, and the remaining dehydrated liquid is returned to an absorption tower via a line 16 or sent to a limestone supply facility 10 as makeup water. Is done.
【００２０】吸収塔内で硫黄酸化物を吸収し、煤塵を捕
集した吸収液滴は吸収塔内下部に設けた吸収塔循環タン
ク７内に落下する。スプレ式の吸収塔内の気液接触は、
スプレノズルから噴霧された吸収液の液滴と排ガスとの
接触であり、硫黄酸化物の吸収については吸収液中の石
灰石濃度、吸収液の噴霧量、吸収塔内の排ガス流速が一
定の場合、吸収塔内での気液接触面積が影響する。その
ため従来技術では吸収塔内の液滴密度が均一となるよう
にスプレノズルを配置していたが、同一の気液接触面積
で吸収塔内に液滴密度が高い領域を形成することにより
排ガスと吸収液との接触が激しくなる。さらに吸収塔内
の排ガス流速を増加させると、排ガスと吸収液との接触
がより激しくなり、硫黄酸化物の排ガスから吸収液内部
への物質移動速度が高まる。従来と同一の気液接触面積
でも液滴密度が高い領域を形成し、吸収塔内の排ガス流
速を増加させることで硫黄酸化物の吸収効率を高めるこ
とが可能となる。The absorbing liquid droplets that have absorbed the sulfur oxides in the absorption tower and collected the dust fall into the absorption tower circulation tank 7 provided in the lower part of the absorption tower. Gas-liquid contact in the spray type absorption tower is
This is the contact between the droplets of the absorbing liquid sprayed from the spray nozzle and the exhaust gas.For the absorption of sulfur oxides, when the limestone concentration in the absorbing liquid, the amount of the absorbing liquid sprayed, and the exhaust gas flow rate in the absorption tower are constant, the absorption The gas-liquid contact area in the column affects. Therefore, in the prior art, the spray nozzle was arranged so that the droplet density in the absorption tower was uniform.However, by forming a region with a high droplet density in the absorption tower with the same gas-liquid contact area, it was absorbed with exhaust gas. Intense contact with liquid. Further, when the flow rate of the exhaust gas in the absorption tower is increased, the contact between the exhaust gas and the absorbing liquid becomes more intense, and the mass transfer speed of the sulfur oxide from the exhaust gas into the absorbing liquid increases. Even with the same gas-liquid contact area as in the past, a region having a high droplet density is formed, and by increasing the exhaust gas flow rate in the absorption tower, it becomes possible to increase the efficiency of sulfur oxide absorption.
【００２１】煤塵の除去は、スプレノズルから噴霧され
た吸収液の液滴と煤塵の物理的な衝突であり、液滴密度
が高く吸収塔内のガス流速が大きいほど液滴と煤塵の衝
突の確率が高くなるので、吸収塔内に液滴密度の高い領
域を形成することで従来よりも高い除塵効率が得られ
る。また、夜間など排ガスを排出するボイラ負荷が低下
した場合、すなわち吸収塔内での処理ガス量が減少した
場合には、運転費低減のため、吸収塔スプレ部において
最上段（最後流）のスプレヘッダから順に、負荷に応じ
て吸収液のスプレを停止させていく。したがって、最低
負荷時には最下段の１段目とその上の２段目のスプレヘ
ッダのみから吸収液をスプレすることになる。この場合
にも吸収液滴密度の高い領域を形成できる。The removal of dust is a physical collision between the droplets of the absorbing liquid sprayed from the spray nozzle and the dust. As the droplet density increases and the gas flow rate in the absorption tower increases, the probability of collision between the droplets and the dust will increase. Therefore, by forming a region having a high droplet density in the absorption tower, it is possible to obtain a higher dust removal efficiency than before. Also, when the boiler load for discharging exhaust gas is reduced, such as at night, that is, when the amount of processing gas in the absorption tower is reduced, the uppermost (last flow) spray header in the absorption tower spray section is used to reduce operating costs. The spraying of the absorbing liquid is stopped in accordance with the load in order from. Therefore, at the time of the minimum load, the absorbing liquid is sprayed only from the spray header of the first stage at the lowest stage and the spray header of the second stage thereabove. Also in this case, a region having a high absorption droplet density can be formed.
【００２２】本発明の効果を確認するため、処理ガス量
１０，０００ｍ3 Ｎ／ｈのパイロットプラントを用いて
試験を実施した。その結果を下記に示す。 １．試験条件 吸収塔入口排ガス量 ：１０，０００ｍ3 Ｎ／ｈ 吸収塔入口硫黄酸化物濃度：２０００ｐｐｍ 吸収塔入口煤塵濃度 ：１００mg／ｍ3 Ｎ 吸収液噴霧量 ：２００ｍ3 ／ｈ スプレヘッダ段数 ：４段 スプレノズル取付け向きおよび吸収塔内排ガス流速 従来技術：４段とも下向き取付け、排ガス流速２．５ｍ
／ｓ 本発明Ｉ：１段目（最下段）上向き ２〜４段目下向き取付け、排ガス流速２．５ｍ／ｓ 本発明II：１段目上向き ２〜４段目下向き取付け、排ガス流速４ｍ／ｓ ２．試験結果In order to confirm the effect of the present invention, a test was conducted using a pilot plant having a processing gas amount of 10,000 m 3 N / h. The results are shown below. 1. Test conditions Absorber inlet exhaust gas amount: 10,000 m 3 N / h Absorber inlet sulfur oxide concentration: 2000 ppm Absorber inlet dust concentration: 100 mg / m 3 N Absorbent spray amount: 200 m 3 / h Number of spray header stages: 4 spray nozzles Installation direction and exhaust gas flow rate in absorption tower Conventional technology: All four stages are installed downward, exhaust gas flow rate 2.5m
/ S Invention I: 1st stage (lowest stage) upward, 2nd to 4th stage downward mounting, exhaust gas flow rate 2.5m / s Invention II: 1st stage upward, 2nd to 4th stage downward mounting, exhaust gas flow rate 4m / s 2. Test results
【００２３】[0023]
【表１】 本発明の他の実施例を図２に示す。本実施例は吸収塔２
において、１段目（最下段）スプレヘッダ３に上向きに
スプレノズル４を取付け２段目スプレヘッダ１７に下向
きのスプレノズル４を取付けてスプレノズル４から噴霧
される吸収液の液滴密度が高い領域を形成し、さらに３
段目スプレヘッダ１８に上向きにスプレノズル４を取付
けることによって４段目スプレヘッダ１９に取付けられ
た下向きのスプレノズル４との間で吸収液の液滴密度が
高い領域を形成する。[Table 1] FIG. 2 shows another embodiment of the present invention. In this embodiment, the absorption tower 2
In the above, the spray nozzle 4 is attached upward to the first (lowest) spray header 3 and the downward spray nozzle 4 is attached to the second spray header 17 to form a region where the droplet density of the absorbing liquid sprayed from the spray nozzle 4 is high, 3 more
By attaching the spray nozzle 4 upward to the stage spray header 18, a region where the droplet density of the absorbing liquid is high is formed between the spray nozzle 4 and the downward spray nozzle 4 attached to the fourth stage spray header 19.
【００２４】この実施例の効果は、吸収塔内に形成する
吸収液の液滴密度が高い領域を増加させることで、硫黄
酸化物および煤塵の除去効率を向上させることが可能と
なる。本実施例において、上向きスプレヘッダと下向き
スプレヘッダの組合わせ数、取付け場所は特に限定され
ず、多数のケースで効果が出る。図１、図２の実施例に
おいて、上向きノズルと下向きノズルのノズル中心位置
をほぼ一致させ、ノズルによって形成される円錐環状噴
霧域を吸収塔断面内にくまなく形成させることにより、
特に噴霧液滴密度が高く、吸収性能の高い吸収塔を形成
できる。The effect of this embodiment is that the efficiency of removing sulfur oxides and dust can be improved by increasing the region where the droplet density of the absorbing liquid formed in the absorption tower is high. In this embodiment, the number of combinations of the upward spray header and the downward spray header and the mounting location are not particularly limited, and the effect is obtained in many cases. In the embodiment of FIGS. 1 and 2, the nozzle center positions of the upward nozzle and the downward nozzle are substantially matched, and the conical annular spray region formed by the nozzle is formed all over the absorption tower section.
In particular, it is possible to form an absorption tower having a high spray droplet density and a high absorption performance.
【００２５】[0025]
【発明の効果】本発明によれば、従来技術よりも硫黄酸
化物および煤塵の除去効率を格段に向上できる。これに
より吸収液の噴霧量を低減でき、吸収液循環ポンプの動
力を低減できる効果がある。また吸収塔径を縮小できる
ので吸収塔設置面積および設備費を低減できる効果があ
る。加えて、吸収塔圧力損失も低減できるので排ガス脱
硫装置の通風ファンの動力を低減できる効果がある。According to the present invention, the removal efficiency of sulfur oxides and dust can be significantly improved as compared with the prior art. This has the effect of reducing the spray amount of the absorbing liquid and reducing the power of the absorbing liquid circulation pump. Further, since the diameter of the absorption tower can be reduced, there is an effect that the installation area and the equipment cost of the absorption tower can be reduced. In addition, since the pressure loss of the absorption tower can be reduced, the power of the ventilation fan of the exhaust gas desulfurization device can be reduced.
【図１】本発明の実施例説明図。FIG. 1 is an explanatory view of an embodiment of the present invention.
【図２】本発明の他の実施例説明図。FIG. 2 is an explanatory view of another embodiment of the present invention.
【図３】従来技術の説明図。FIG. 3 is an explanatory diagram of a conventional technique.
【図４】スプレノズルからの噴霧液滴の説明図。FIG. 4 is an explanatory diagram of spray droplets from a spray nozzle.
【図５】他の従来技術の説明図。FIG. 5 is an explanatory diagram of another conventional technique.
１…排ガス、１ａ…吸収塔排ガス入口、２…吸収塔、３
…最下段スプレヘッダ、４…スプレノズル、５…ミスト
エリミネータ、５ａ…吸収塔出口ダクト、６…浄化ガ
ス、７…吸収塔循環タンク、８…空気、１２…吸収液抜
出しポンプ、１７…２段目スプレヘッダ、１８…３段目
スプレヘッダ、１９…４段目スプレヘッダ、２３…循環
ポンプ。DESCRIPTION OF SYMBOLS 1 ... Exhaust gas, 1a ... Absorption tower exhaust gas inlet, 2 ... Absorption tower, 3
… Bottom spray header, 4 spray nozzle, 5 mist eliminator, 5a absorption tower outlet duct, 6 purification gas, 7 absorption tank circulation tank, 8 air, 12 absorption liquid discharge pump, 17 second spray header , 18 ... third stage spray header, 19 ... fourth stage spray header, 23 ... circulation pump.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 加来 宏行 広島県呉市宝町３番36号 バブコック日 立株式会社 呉研究所内 審査官 森 健一 (56)参考文献 特開 平４−78412（ＪＰ，Ａ) 特開 昭62−193625（ＪＰ，Ａ) 特開 平５−7729（ＪＰ，Ａ) 特開 昭48−46967（ＪＰ，Ａ) 特開 昭56−136617（ＪＰ，Ａ) 実開 平４−134421（ＪＰ，Ｕ) 実開 昭55−21052（ＪＰ，Ｕ) 実開 昭58−174228（ＪＰ，Ｕ) 実開 昭60−24331（ＪＰ，Ｕ) 実開 昭62−13529（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.7，ＤＢ名) B01D 53/34 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroyuki Kaku 3-36 Takara-cho, Kure-shi, Hiroshima Examiner at Kure Research Laboratory, Babcock Hitachi Ltd. Kenichi Mori (56) References JP-A-4-78412 (JP, A) JP-A-62-193625 (JP, A) JP-A-5-7729 (JP, A) JP-A-48-46967 (JP, A) JP-A-56-136617 (JP, A) -134421 (JP, U) Fully open 55-21052 (JP, U) Fully open, 58-174228 (JP, U) Fully open, 60-24331 (JP, U) Really open, 62-13529 (JP, U) (58) Field surveyed (Int. Cl. 7 , DB name) B01D 53/34
Claims (1)
通過させ、吸収塔内に配置された複数段のスプレヘッダ
に設けたスプレノズルより吸収液を噴霧して排ガス中の
硫黄酸化物を吸収除去する湿式排ガス脱硫方法におい
て、吸収塔内の排ガス速度を３ｍ／ｓを超え７ｍ／ｓ以
下とするとともに、最下段のスプレヘッダのスプレノズ
ルを上向き噴射、次の上方段のスプレヘッダのスプレノ
ズルを下向き噴射とし、かつそれらより上段にもスプレ
ヘッダを設けてスプレノズルから噴射できるようにし、
吸収塔出口後流排ガスダクトに設けた縦型波板ミストエ
リミネータにより排ガス中のミストを除去し、かつ吸収
塔内での排ガスの硫黄酸化物処理量が減少した場合に
は、上段のスプレヘッダから負荷に応じて吸収液の噴射
を停止することを特徴とする湿式排ガス脱硫方法。 An exhaust gas is passed upward from below in a vertical absorption tower, and the absorption liquid is sprayed from spray nozzles provided in a plurality of spray headers arranged in the absorption tower to absorb sulfur oxides in the exhaust gas. In the wet exhaust gas desulfurization method for removal, the exhaust gas velocity in the absorption tower is set to more than 3 m / s and 7 m / s or less, the spray nozzle of the lowermost spray header is upwardly injected, and the spray nozzle of the next upper spray header is downwardly injected. , And a spray header is also provided above them so that the spray nozzle can spray,
When the mist in the exhaust gas is removed by the vertical corrugated sheet mist eliminator installed in the exhaust gas duct downstream of the absorption tower, and when the sulfur oxide treatment amount of the exhaust gas in the absorption tower is reduced, load from the upper spray header A wet exhaust gas desulfurization method, wherein the injection of the absorbing liquid is stopped according to the following conditions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00540694A JP3333031B2 (en) | 1994-01-21 | 1994-01-21 | Wet exhaust gas desulfurization method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00540694A JP3333031B2 (en) | 1994-01-21 | 1994-01-21 | Wet exhaust gas desulfurization method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07204458A JPH07204458A (en) | 1995-08-08 |
| JP3333031B2 true JP3333031B2 (en) | 2002-10-07 |
Family
ID=11610269
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP00540694A Expired - Fee Related JP3333031B2 (en) | 1994-01-21 | 1994-01-21 | Wet exhaust gas desulfurization method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3333031B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170094676A (en) * | 2016-02-11 | 2017-08-21 | 주식회사 에이런 | air purifing apparatus by water membrane |
| WO2021200942A1 (en) * | 2020-03-31 | 2021-10-07 | 三菱パワー株式会社 | Absorption tower of desulphurization device |
| CN111841283A (en) * | 2020-07-31 | 2020-10-30 | 中冶焦耐(大连)工程技术有限公司 | A kind of AS tail gas scrubbing device and method |
-
1994
- 1994-01-21 JP JP00540694A patent/JP3333031B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07204458A (en) | 1995-08-08 |
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