JP2010137201A - Mercury removing method and device - Google Patents

Mercury removing method and device Download PDF

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JP2010137201A
JP2010137201A JP2008318590A JP2008318590A JP2010137201A JP 2010137201 A JP2010137201 A JP 2010137201A JP 2008318590 A JP2008318590 A JP 2008318590A JP 2008318590 A JP2008318590 A JP 2008318590A JP 2010137201 A JP2010137201 A JP 2010137201A
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mercury
mbt
exhaust gas
mercaptobenzothiazole
desulfurization
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JP4905996B2 (en
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Koichi Yokoyama
公一 横山
Shigeto Omine
成人 大峰
Ryohei Maeda
領平 前田
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Mitsubishi Power Ltd
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Babcock Hitachi KK
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a mercury removing method and a device suppressing re-discharge of mercury without adding an oxidizer or a halide. <P>SOLUTION: The mercury removing method includes bringing treating object gas containing sulfur oxides and a water-soluble mercury compound into contact with aqueous slurry containing a calcium carbonate-based desulfurization agent and MBT like an alkali metal salt of 2-mercaptobenzothiazole (MBT). Addition of MBT to the desulfurization agent slurry containing mercury component suppresses re-discharge of mercury rather than the oxidizer or halide, to suppress corrosion of the device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、ボイラなどの燃焼装置から排出される排ガス中の有害物質を除去する排煙処理方法と装置に関わり、特に、排ガス中の水銀の除去方法と装置に関するものである。   The present invention relates to a smoke treatment method and apparatus for removing harmful substances in exhaust gas discharged from a combustion apparatus such as a boiler, and more particularly to a method and apparatus for removing mercury in exhaust gas.

火力発電所等において、水銀（排煙中では主として金属水銀または塩化水銀として存在）が石炭などの化石燃料の燃焼に伴って発生し、排煙中に含まれる水銀含有量は多くないが、水銀成分の毒性の強さから処理技術の普及が望まれている。排ガス中の水銀除去は盛んに検討されており（例えば、特開２００４−３１３８３３号公報）、排ガス中の水銀を触媒で塩化水銀（II）に酸化した後、水銀除去装置として湿式脱硫装置のような吸収塔を用い、排ガスと吸収液を接触させ、該吸収液中に水銀化合物を溶解させて除去する方法である。   In thermal power plants, mercury (predominantly present as metallic mercury or mercury chloride in flue gas) is generated by the combustion of fossil fuels such as coal, and the amount of mercury contained in flue gas is not high. The spread of treatment technology is desired due to the toxic strength of the components. Mercury removal in exhaust gas has been actively studied (for example, Japanese Patent Application Laid-Open No. 2004-313833), and after mercury in exhaust gas is oxidized to mercury (II) with a catalyst, it is used as a wet desulfurization device as a mercury removal device. In this method, an exhaust tower is used, the exhaust gas is brought into contact with the absorbing solution, and the mercury compound is dissolved and removed in the absorbing solution.

運転条件によっては、液中の塩化水銀が還元されて金属水銀となり、液中からガス中へ再放出される場合がある。これを防ぐために酸化剤（例えば、次亜塩素酸ナトリウム、過酸化水素）やハロゲン化物が吸収液に添加されていた（例えば、特開２００４−３１３８３３号公報や特開２００８−３６５５４号公報）。
特開２００４−３１３８３３号公報 特開２００８−３６５５４号公報 Depending on the operating conditions, mercury chloride in the liquid may be reduced to metallic mercury and re-released from the liquid into the gas. In order to prevent this, an oxidizing agent (for example, sodium hypochlorite, hydrogen peroxide) or a halide has been added to the absorbing solution (for example, Japanese Patent Application Laid-Open Nos. 2004-313833 and 2008-36554).
JP 2004-313833 A JP 2008-36554 A

特許文献１記載の酸化した水銀を脱硫装置にて吸収・除去する方法では、吸収した水銀の一部は２価の水銀イオンとして吸収液中に溶解している。脱硫装置が連続的に運転されることで、吸収液中の水銀は濃縮されることになる。さらに、吸収液中に２価の水銀イオンが存在している中で脱硫装置が運転されていると、吸収液中に溶解していた２価の水銀イオンが還元されて金属水銀となり、排ガス中へ再放出する現象が確認されている。   In the method of absorbing and removing oxidized mercury described in Patent Document 1, a part of the absorbed mercury is dissolved in the absorbing solution as divalent mercury ions. By continuously operating the desulfurization apparatus, mercury in the absorption liquid is concentrated. In addition, if the desulfurization unit is operated in the presence of divalent mercury ions in the absorption liquid, the divalent mercury ions dissolved in the absorption liquid are reduced to metallic mercury, and in the exhaust gas. Phenomenon of re-emission is confirmed.

従来の排ガス処理システムの機器構成において、脱硫装置において再放出した金属水銀は脱硫装置以降では排ガス中から分離・除去されず、外気へ放出されてしまう。これを防止するために、前記次亜塩素酸ナトリウムや過酸化水素のような酸化剤を水銀吸収液に添加する。   In the apparatus configuration of the conventional exhaust gas treatment system, the metal mercury re-released in the desulfurization apparatus is not separated and removed from the exhaust gas after the desulfurization apparatus and is released to the outside air. In order to prevent this, an oxidizing agent such as sodium hypochlorite or hydrogen peroxide is added to the mercury absorbing solution.

前記次亜塩素酸ナトリウムは酸化還元電位が高い。このため、ステンレス（ＳＵＳ３１６、ＳＵＳ３１６Ｌなど）によって形成された部材が腐食してしまい装置の寿命を縮めてしまうことが知られている（特開２００８−３６５５４号公報）。一方、該水銀吸収液にハロゲン化物を添加する方法も、鉄鋼材料の孔食を促進することが知られている（理化学辞典第４版）。   The sodium hypochlorite has a high redox potential. For this reason, it is known that members formed of stainless steel (SUS316, SUS316L, etc.) corrode and shorten the life of the device (Japanese Patent Laid-Open No. 2008-36554). On the other hand, a method of adding a halide to the mercury absorbing solution is also known to promote pitting corrosion of steel materials (RIKEN Dictionary 4th edition).

本発明の課題は、酸化剤やハロゲン化物を添加することなく水銀の再放出を抑制できるような水銀除去方法と装置を提供することにある。   An object of the present invention is to provide a mercury removal method and apparatus capable of suppressing the re-release of mercury without adding an oxidizing agent or a halide.

本発明の上記課題は、次の構成により解決される。
請求項１記載の発明は、硫黄酸化物及び水溶性水銀化合物を含む処理対象ガスを炭酸カルシウム系の脱硫剤と２−メルカプトベンゾチアゾールを含んだ水スラリに接触させる水銀除去方法である。
請求項２記載の発明は、前記水スラリに２−メルカプトベンゾチアゾールのアルカリ金属塩を添加する請求項１記載の水銀除去方法である。
請求項３記載の発明は、炭酸カルシウム系の脱硫剤を含み、かつ、２−メルカプトベンゾチアゾールを添加した水スラリに硫黄酸化物及び水溶性水銀化合物を含む処理対象ガスを接触させる脱硫処理室を備えた水銀除去装置である。 The above-described problems of the present invention are solved by the following configuration.
Invention of Claim 1 is the mercury removal method which makes the process target gas containing a sulfur oxide and a water-soluble mercury compound contact the water slurry containing a calcium carbonate type | system | group desulfurization agent and 2-mercaptobenzothiazole.
The invention according to claim 2 is the mercury removing method according to claim 1, wherein an alkali metal salt of 2-mercaptobenzothiazole is added to the water slurry.
The invention according to claim 3 includes a desulfurization treatment chamber in which a treatment slurry containing a sulfur oxide and a water-soluble mercury compound is brought into contact with a water slurry containing a calcium carbonate-based desulfurization agent and added with 2-mercaptobenzothiazole. It is a mercury removal device equipped.

（作用）
石炭に含まれる水銀は脱硝触媒によって塩素と反応し、水溶性の塩化水銀（II）になることが知られている（特開２００４−３１３８３３号公報参照）。塩化水銀は湿式脱硫装置で吸収液に溶解・回収される。しかし、該吸収液中の塩化水銀が亜硫酸イオンにより金属水銀に還元され、生成した金属水銀は排ガスとともに飛散する現象（これを水銀の再放出と言う）が起こる場合があり、従来は次亜塩素酸ナトリウムや過酸化水素水のような酸化剤又はハロゲン化物を吸収液に添加することにより、再放出を抑制していた。 (Function)
It is known that mercury contained in coal reacts with chlorine by a denitration catalyst to become water-soluble mercury (II) chloride (see JP 2004-313833 A). Mercury chloride is dissolved and recovered in the absorbing solution by wet desulfurization equipment. However, mercury chloride in the absorbing solution is reduced to metallic mercury by sulfite ions, and the produced metallic mercury may be scattered with exhaust gas (this is called mercury re-release). Re-release was suppressed by adding an oxidizing agent or halide such as sodium acid or hydrogen peroxide to the absorbing solution.

これに対して、本発明者は、ハロゲン化水銀を含んだ上記の吸収液に２−メルカプトベンゾチアゾール（以下、ＭＢＴと略す）を添加することにより、酸化剤又はハロゲン化物よりも水銀の再放出が抑制されることを見出だした。   In contrast, the inventor added 2-mercaptobenzothiazole (hereinafter abbreviated as MBT) to the above-described absorbing solution containing mercury halide, thereby re-releasing mercury rather than the oxidizing agent or halide. Was found to be suppressed.

なお、銅、カドミウム及び鉛のイオンについて、ＭＢＴを添加することにより沈殿回収できることは知られていた（松岡ほか：メルカプトベンゾチアゾールによる廃水中の重金属イオンの浮選除去、東北大學選鑛製錬研究所彙報、Vol３１、 No.２(１９７６)第１０９−１１７頁）。本発明者は、上記文献の他の重金属同様、ＭＢＴ（化学式：Ｃ7Ｈ5ＮＳ2）が水銀イオンと反応してＨｇ（化学式：Ｃ7Ｈ４ＮＳ2）2のような塩を形成するためではないかと推測している。 In addition, it was known that precipitation of copper, cadmium and lead ions can be recovered by adding MBT (Matsuoka et al .: Flotation removal of heavy metal ions in wastewater with mercaptobenzothiazole, Tohoku Univ. Vocabulary, Vol 31, No. 2 (1976) pp. 109-117). As in the case of other heavy metals described above, the present inventor reacts MBT (chemical formula: C 7 H 5 NS 2 ) with mercury ions to form a salt such as Hg (chemical formula: C 7 H 4 NS 2 ) 2. I guess that's because.

さらに、本発明者はＭＢＴのアルカリ金属塩でも同様の効果があることを確認した。ＭＢＴ（和光化学工業、MSDS No. JW130099）は水に難溶性であるため、可溶性の物質に比べて、液中に均一に分散させるのは難しい。そのため、液の攪拌やＭＢＴの添加方法によって水銀の再放出の抑制効果が変化することも考えられる。   Furthermore, the present inventor has confirmed that MBT alkali metal salt has the same effect. Since MBT (Wako Chemical Industries, MSDS No. JW130099) is hardly soluble in water, it is difficult to uniformly disperse it in a liquid as compared with a soluble substance. Therefore, it is conceivable that the effect of suppressing the rerelease of mercury changes depending on the stirring of the liquid and the addition method of MBT.

ＭＢＴのアルカリ塩は水に可溶性であるため、該吸収液に均一に溶解可能させることができ、今回、本発明者によって水銀の再放出抑制の効果を確認したところ、ＭＢＴと同等であることを確認した。ＭＢＴのアルカリ塩を用いることにより、より簡単に吸収液に分散させることが可能になる。   Since the alkali salt of MBT is soluble in water, it can be uniformly dissolved in the absorbing solution. This time, the present inventors have confirmed the effect of suppressing the rerelease of mercury and found that it is equivalent to MBT. confirmed. By using an alkali salt of MBT, it can be more easily dispersed in the absorbing liquid.

２、４、６−トリメルカプト−ｓ−トリアジントリナトリウム塩の溶液（例えば商品名：ＴＭＴ−１５（Ｅｖｏｎｉｋ製）、サンチオールＮ−Ｗ（三協化成））が重金属イオンの沈殿除去用に供給されているが、ＭＢＴは同様に水銀イオン以外の銅、カドミウム、鉛などの重金属イオンの沈殿除去にも使用できる。
なお、本発明に基づく水銀除去装置の上流に金属水銀を可溶性の塩化水銀に酸化する脱硝触媒又は酸化触媒を設置すれば、該吸収液で水銀をより効率的に除去することが可能になる。 A solution of 2,4,6-trimercapto-s-triazine trisodium salt (for example, trade name: TMT-15 (manufactured by Evonik), Santhiol N-W (Sankyo Kasei)) is supplied for precipitation removal of heavy metal ions However, MBT can also be used for precipitation removal of heavy metal ions such as copper, cadmium and lead other than mercury ions.
If a denitration catalyst or an oxidation catalyst that oxidizes metallic mercury into soluble mercury chloride is installed upstream of the mercury removing apparatus according to the present invention, mercury can be removed more efficiently by the absorbing solution.

上記のように２モルのＭＢＴと１モルの水銀イオンが反応すると考えられるので、該吸収液に添加するＭＢＴの添加モル濃度は水銀イオンの２倍以上となるのが望ましい。もし、他の重金属イオンが存在する場合、そのイオンとの反応で消費される化学量論比のＭＢＴ量を積算し、それ以上の含有量となるように該吸収液のＭＢＴ濃度を決定する必要がある。   Since it is considered that 2 mol of MBT and 1 mol of mercury ion react as described above, it is desirable that the added molar concentration of MBT added to the absorbing solution is at least twice that of mercury ion. If other heavy metal ions are present, it is necessary to integrate the MBT amount of the stoichiometric ratio consumed in the reaction with the ions and determine the MBT concentration of the absorbing solution so that the content is higher than that. There is.

本発明によって、ハロゲン化物の代わりに腐食性の低いＭＢＴを水銀除去装置の吸収液に添加することによって、水銀の再放出と装置の腐食をいずれも抑制できる。   According to the present invention, both the re-release of mercury and the corrosion of the apparatus can be suppressed by adding MBT having low corrosivity instead of the halide to the absorbing liquid of the mercury removing apparatus.

以下、本発明の実施例について図面を用いて説明する。
図１は本発明の水銀除去装置が適用された排ガス処理システムの一実施形態の系統図であり、図２は本発明を適用した水銀除去装置の一実施形態の構成図であり、図３は従来発明を適用した比較例２の水銀除去装置の構成図である。 Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a system diagram of an embodiment of an exhaust gas treatment system to which the mercury removing apparatus of the present invention is applied, FIG. 2 is a configuration diagram of an embodiment of the mercury removing apparatus to which the present invention is applied, and FIG. It is a block diagram of the mercury removal apparatus of the comparative example 2 to which a conventional invention is applied.

図１に示すようにこの排ガス処理システムは、ボイラ１、脱硝装置２、エアヒータ（Ａ／Ｈ）３、ガスガスヒータ（ＧＧＨ）熱回収部４、電気集塵機（ＥＰ）５、水銀除去装置（脱硫装置）６、及び煙突７を排ガス流路の上流側から順次配置しており、それぞれの機器は排ガスダクトなどで接続されている。   As shown in FIG. 1, this exhaust gas treatment system includes a boiler 1, a denitration device 2, an air heater (A / H) 3, a gas gas heater (GGH) heat recovery unit 4, an electrostatic precipitator (EP) 5, a mercury removal device (desulfurization device). ) 6 and the chimney 7 are sequentially arranged from the upstream side of the exhaust gas flow path, and each device is connected by an exhaust gas duct or the like.

ボイラ１から排出された石炭の燃焼排ガスは脱硝装置２に導入され、排ガス中のＮＯｘが除去される。ＮＯｘが除去された排ガスは、Ａ／Ｈ３を経てＧＧＨ熱回収部４で排ガスの熱エネルギーを回収し、ＥＰ５にて煤塵が除去された後、脱硫装置６に導入され、排ガス中のＳＯ2が除去される。脱硫装置６から排出される排ガスは、煙突７より外気へ放出される。 The combustion exhaust gas of coal discharged from the boiler 1 is introduced into the denitration device 2, and NOx in the exhaust gas is removed. The exhaust gas from which NOx is removed passes through A / H3, recovers the thermal energy of the exhaust gas in the GGH heat recovery section 4, and after removing dust in EP5, is introduced into the desulfurization device 6, and the SO 2 in the exhaust gas is removed. Removed. The exhaust gas discharged from the desulfurization device 6 is discharged from the chimney 7 to the outside air.

脱硫装置６では、ボイラの排ガスは、ガス入口部１０から導入されスプレノズル１２から噴霧される吸収液と気液接触し、排ガス中のＳＯ2が除去された後、ガス出口部１１から排出される。また、前記気液接触した吸収液は、脱硫装置６の吸収塔本体内を下降して吸収液タンク８に一時的に溜められる。吸収液タンク８では、空気供給管１４から供給される空気が酸化用撹拌機１５の回転するプロペラによって微細化され、空気中の酸素が吸収液中に溶解する。吸収液タンク８では吸収したＳＯ2と図示していない炭酸カルシウム供給系統より該タンク８に供給される炭酸カルシウムの中和反応により亜硫酸カルシウムが生成され、吸収液中に溶解した酸素により酸化され石膏が生成する。石膏がスラリとして存在する吸収液タンク８内の吸収液は循環ポンプ１３によって循環ライン９から再びスプレノズル１２に送られ、一部は系外へ排出される。 In the desulfurization device 6, the boiler exhaust gas comes into gas-liquid contact with the absorbing liquid introduced from the gas inlet 10 and sprayed from the spray nozzle 12, and after SO 2 in the exhaust gas is removed, it is discharged from the gas outlet 11. . Further, the absorption liquid in contact with the gas and liquid descends in the absorption tower body of the desulfurization apparatus 6 and is temporarily stored in the absorption liquid tank 8. In the absorption liquid tank 8, the air supplied from the air supply pipe 14 is refined by the propeller rotating by the oxidizing stirrer 15, and oxygen in the air is dissolved in the absorption liquid. In the absorption liquid tank 8, calcium sulfite is generated by neutralization reaction between the absorbed SO 2 and calcium carbonate supplied to the tank 8 from a calcium carbonate supply system (not shown), and is oxidized by oxygen dissolved in the absorption liquid and gypsum. Produces. The absorbent in the absorbent tank 8 where gypsum is present as a slurry is sent again from the circulation line 9 to the spray nozzle 12 by the circulation pump 13, and a part thereof is discharged out of the system.

ここで、ボイラ１から排出される排ガス中にはμｇ／ｍ3Ｎオーダーの水銀蒸気が含まれる。排ガス中の水銀の形態は、０価金属水銀と２価の酸化された水銀が大半である。２価の酸化された水銀は０価金属水銀より蒸気圧が低く、煤塵等に吸着され、吸収液に吸収されやすく、排ガスから除去しやすいという特徴をもつ。
従って、排ガス中の水銀の一部は、脱硝装置２、Ａ／Ｈ３及びＧＧＨ熱回収部４を順次通過する間に煤塵に吸着され、ＥＰ５で捕集された煤塵とともに系外に排出される。 Here, the exhaust gas discharged from the boiler 1 contains mercury vapor in the order of μg / m 3 N. The form of mercury in the exhaust gas is mostly zero-valent metal mercury and divalent oxidized mercury. Divalent oxidized mercury has a lower vapor pressure than zero-valent metal mercury, is adsorbed by dust and the like, is easily absorbed by the absorbing solution, and is easily removed from the exhaust gas.
Accordingly, a part of mercury in the exhaust gas is adsorbed by soot while sequentially passing through the denitration device 2, A / H3 and GGH heat recovery section 4, and is discharged out of the system together with soot collected by EP5.

さらに、脱硫装置６において、排ガス中の水銀化合物の大部分は炭酸カルシウムを水に懸濁させた吸収液スラリに溶解し、その一部は吸収液スラリ中の石膏粒子に吸着され、石膏とともに系外に排出される。このとき、吸収液に吸収される排ガス中の水銀のほとんどは２価の酸化された水銀であり、０価金属水銀は吸収されない。２価の酸化された水銀は吸収液中では２価の水銀イオンとして溶解している。   Further, in the desulfurization apparatus 6, most of the mercury compounds in the exhaust gas are dissolved in the absorption liquid slurry in which calcium carbonate is suspended in water, and part of the mercury compounds are adsorbed on the gypsum particles in the absorption liquid slurry, and the system together with the gypsum. Discharged outside. At this time, most of the mercury in the exhaust gas absorbed by the absorbing solution is divalent oxidized mercury, and zero-valent metallic mercury is not absorbed. Divalent oxidized mercury is dissolved as divalent mercury ions in the absorbing solution.

通常、脱硫装置６の吸収液タンク８内には空気が供給され、酸化雰囲気になっている。ところで吸収液タンク８内の吸収液中に２価の水銀イオンが存在している中で、脱硫装置６が運転されていると、吸収液中で還元性物質が増加し、吸収液中に溶解していた２価の水銀イオンが還元されて０価金属水銀となる。溶解性のきわめて低い０価金属水銀は吸収液中から排ガス中へ再び放出してしまい、煙突７から外気へ排出される排ガス中の水銀濃度が高くなる（表１の比較例１参照）。   Usually, air is supplied into the absorbing liquid tank 8 of the desulfurization apparatus 6 to form an oxidizing atmosphere. By the way, when the desulfurization device 6 is operated in the presence of divalent mercury ions in the absorption liquid in the absorption liquid tank 8, reducing substances increase in the absorption liquid and dissolve in the absorption liquid. The divalent mercury ions that have been reduced are reduced to zero valent metal mercury. Zero-valent metal mercury having extremely low solubility is released again from the absorbing solution into the exhaust gas, and the mercury concentration in the exhaust gas discharged from the chimney 7 to the outside air becomes high (see Comparative Example 1 in Table 1).

ここで、ＭＢＴ粉末供給用タンク１８から該吸収液タンク８の吸収液中の濃度がそれぞれ１０、１００、１０００ｐｐｍ（ｐｐｍ＝ｍｇ／Ｌ）になるようＭＢＴ粉末を添加することにより、水銀除去装置（脱硫装置）６からの水銀の再放出を抑制できる（表１の実施例１参照）。   Here, by adding MBT powder from the MBT powder supply tank 18 so that the concentration in the absorption liquid in the absorption liquid tank 8 is 10, 100, and 1000 ppm (ppm = mg / L), respectively, a mercury removing device ( The re-release of mercury from the desulfurization apparatus 6 can be suppressed (see Example 1 in Table 1).

また、吸収液の循環ライン９へのＭＢＴ添加用タンク１７からＭＢＴのナトリウム塩を添加しても同様の効果が得られた（表１の実施例２参照）。
さらに、実施例１と同じＭＢＴ濃度になるようＭＢＴのナトリウム塩を該吸収液タンク８に添加した場合も、同様に水銀の再放出が抑制された（実施例３）。
また、実施例１と同じＭＢＴ濃度になるようＭＢＴのカリウム塩を該吸収液タンク８に添加した場合も、同様に水銀の再放出が抑制された（実施例４）。 Further, the same effect was obtained by adding MBT sodium salt from the MBT addition tank 17 to the absorption liquid circulation line 9 (see Example 2 in Table 1).
Further, when MBT sodium salt was added to the absorbent tank 8 so as to have the same MBT concentration as in Example 1, rerelease of mercury was similarly suppressed (Example 3).
Further, when MBT potassium salt was added to the absorbent tank 8 so as to have the same MBT concentration as in Example 1, the rerelease of mercury was similarly suppressed (Example 4).

一方、図３に示すヨウ化カリウム液タンク１６からヨウ化カリウム液を該吸収液タンク８に添加した場合も、実施例１と同じく水銀の再放出が抑制された（比較例２）。なお、図３は図２のＭＢＴ粉末供給用タンク１８とＭＢＴ添加用タンク１７をヨウ化カリウム液タンク１６に換えた構成である。   On the other hand, when the potassium iodide solution was added from the potassium iodide solution tank 16 shown in FIG. 3 to the absorbing solution tank 8, the rerelease of mercury was suppressed as in Example 1 (Comparative Example 2). 3 shows a configuration in which the MBT powder supply tank 18 and the MBT addition tank 17 of FIG.

Figure 2010137201
Figure 2010137201

水銀除去装置（脱硫装置）での水銀再放出は、排煙処理システム全体での水銀除去性能に大きく関わる問題であることから、本発明は、将来産業上の利用可能性が高い。   Since mercury re-emission in the mercury removal apparatus (desulfurization apparatus) is a problem largely related to mercury removal performance in the entire flue gas treatment system, the present invention has high industrial applicability in the future.

本発明を適用した排ガス処理システムの一実施形態の系統図である。1 is a system diagram of an embodiment of an exhaust gas treatment system to which the present invention is applied. 本発明を適用した水銀除去装置の一実施形態の構成図である。It is a block diagram of one Embodiment of the mercury removal apparatus to which this invention is applied. 従来発明を適用した比較例２の水銀除去装置の構成図である。It is a block diagram of the mercury removal apparatus of the comparative example 2 to which a conventional invention is applied.

符号の説明Explanation of symbols

１ ボイラ ２ 脱硝装置
３ エアヒータ（Ａ／Ｈ）
４ ガスガスヒータ（ＧＧＨ）熱回収部
５ 電気集塵機（ＥＰ）
６ 水銀除去装置(脱硫装置)
７ 煙突 ８ 吸収液タンク
９ 循環ライン １０ 排ガス入口
１１ 排ガス出口 １２ スプレノズル
１３ 循環ポンプ １４ 空気供給菅
１５ 攪拌機
１６ ヨウ化カリウム液タンク
１７ 吸収液の循環ラインへの添加用タンク
１８ ＭＢＴ粉末供給用タンク 1 Boiler 2 Denitration equipment 3 Air heater (A / H)
4 Gas gas heater (GGH) heat recovery unit 5 Electric dust collector (EP)
6 Mercury removal equipment (desulfurization equipment)
7 Chimney 8 Absorption liquid tank 9 Circulation line 10 Exhaust gas inlet 11 Exhaust gas outlet 12 Spray nozzle 13 Circulation pump 14 Air supply tank 15 Stirrer 16 Potassium iodide liquid tank 17 Tank for addition to absorption liquid circulation line 18 MBT powder supply tank

Claims (3)

硫黄酸化物及び水溶性水銀化合物を含む処理対象ガスを炭酸カルシウム系の脱硫剤と２−メルカプトベンゾチアゾールを含んだ水スラリに接触させることを特徴とする水銀除去方法。   A mercury removal method comprising contacting a gas to be treated containing a sulfur oxide and a water-soluble mercury compound with a water slurry containing a calcium carbonate-based desulfurization agent and 2-mercaptobenzothiazole. 前記水スラリに２−メルカプトベンゾチアゾールのアルカリ金属塩を添加することを特徴とする請求項１記載の水銀除去方法。   The mercury removal method according to claim 1, wherein an alkali metal salt of 2-mercaptobenzothiazole is added to the water slurry. 炭酸カルシウム系の脱硫剤を含み、かつ、２−メルカプトベンゾチアゾールを添加した水スラリに硫黄酸化物及び水溶性水銀化合物を含む処理対象ガスを接触させる脱硫処理室を備えたことを特徴とする水銀除去装置。   Mercury comprising a desulfurization treatment chamber in which a treatment gas containing a sulfur oxide and a water-soluble mercury compound is brought into contact with a water slurry containing a calcium carbonate-based desulfurization agent and added with 2-mercaptobenzothiazole. Removal device.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4935504B1 (en) * 1970-12-15 1974-09-24
JPH01203026A (en) * 1988-02-08 1989-08-15 Babcock Hitachi Kk Wet exhaust gas desulfurizer and its absorbing solution and cooling dusting solution
JP2003053142A (en) * 2001-08-09 2003-02-25 Mitsubishi Heavy Ind Ltd Method and equipment for removing mercury in exhaust gas
JP2006029673A (en) * 2004-07-15 2006-02-02 Ishikawajima Harima Heavy Ind Co Ltd Method and device for removing gaseous mercury in exhaust gas
JP2007007612A (en) * 2005-07-01 2007-01-18 Mitsubishi Heavy Ind Ltd Exhaust gas treatment device and exhaust gas treatment method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4935504B1 (en) * 1970-12-15 1974-09-24
JPH01203026A (en) * 1988-02-08 1989-08-15 Babcock Hitachi Kk Wet exhaust gas desulfurizer and its absorbing solution and cooling dusting solution
JP2003053142A (en) * 2001-08-09 2003-02-25 Mitsubishi Heavy Ind Ltd Method and equipment for removing mercury in exhaust gas
JP2006029673A (en) * 2004-07-15 2006-02-02 Ishikawajima Harima Heavy Ind Co Ltd Method and device for removing gaseous mercury in exhaust gas
JP2007007612A (en) * 2005-07-01 2007-01-18 Mitsubishi Heavy Ind Ltd Exhaust gas treatment device and exhaust gas treatment method

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