WO2010021237A1 - Apparatus for treating discharge gas and system for treating discharge gas - Google Patents

Apparatus for treating discharge gas and system for treating discharge gas Download PDF

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Publication number
WO2010021237A1
WO2010021237A1 PCT/JP2009/063819 JP2009063819W WO2010021237A1 WO 2010021237 A1 WO2010021237 A1 WO 2010021237A1 JP 2009063819 W JP2009063819 W JP 2009063819W WO 2010021237 A1 WO2010021237 A1 WO 2010021237A1
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Prior art keywords
exhaust gas
mercury
denitration catalyst
gas treatment
hydrogen chloride
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PCT/JP2009/063819
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French (fr)
Japanese (ja)
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利久磨 四條
展康 坂田
敏浩 佐藤
盛紀 村上
展行 鵜飼
勝己 野地
正志 清澤
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三菱重工業株式会社
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/64—Heavy metals or compounds thereof, e.g. mercury
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8621—Removing nitrogen compounds
    • B01D53/8625—Nitrogen oxides
    • B01D53/8631—Processes characterised by a specific device
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2062—Ammonia
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/50—Inorganic acids
    • B01D2251/502—Hydrochloric acid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D2255/10—Noble metals or compounds thereof
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    • B01D2255/20738—Iron
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D2255/20—Metals or compounds thereof
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    • B01D2255/20746—Cobalt
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D2255/20753—Nickel
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D2255/20769—Molybdenum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
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    • B01D2255/20776—Tungsten
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/30—Silica
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/50—Zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B01D2255/902—Multilayered catalyst
    • B01D2255/9025—Three layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/60—Heavy metals or heavy metal compounds
    • B01D2257/602—Mercury or mercury compounds
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/10—Nitrogen; Compounds thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/20—Sulfur; Compounds thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/60—Heavy metals; Compounds thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2219/00—Treatment devices
    • F23J2219/10—Catalytic reduction devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2219/00—Treatment devices
    • F23J2219/40—Sorption with wet devices, e.g. scrubbers

Definitions

  • the present invention relates to an exhaust gas treatment device and an exhaust gas treatment system for oxidizing mercury in exhaust gas discharged from a combustion device.
  • coal fired boilers are provided with a wet desulfurization device for removing sulfur content in the exhaust gas.
  • a desulfurization device for removing sulfur content in the exhaust gas.
  • chlorine (Cl) content in the exhaust gas increases, the proportion of divalent metal mercury (Hg) soluble in water It is widely known that mercury tends to be collected by the desulfurization apparatus.
  • a removal method using an adsorbent such as activated carbon or a selenium filter is known.
  • an adsorbent such as activated carbon or a selenium filter
  • a special adsorption removal means is required, and a large-capacity exhaust gas such as power plant exhaust gas is treated. Not suitable for.
  • a chlorinating agent is gas-sprayed in the upstream process of the high-temperature denitration catalyst layer in the flue, and mercury is oxidized (chlorinated) on the denitration catalyst to produce water.
  • a method is proposed in which the product is converted to a characteristic mercury chloride and then absorbed by a downstream wet desulfurization apparatus (see, for example, Patent Document 1 and Patent Document 2).
  • an apparatus and a technique for spraying a gas to a flue are put into practical use by NH 3 spraying of a denitration catalyst layer and gas spraying of a chlorinating agent.
  • Fig. 5 shows a schematic diagram of an exhaust gas treatment system for a coal fired boiler.
  • the conventional exhaust gas treatment system 100 removes nitrogen oxide (NOx) in the exhaust gas 12 from the coal-fired boiler 11 that supplies coal as the fuel F, and chlorinates in the exhaust gas 12.
  • NOx nitrogen oxide
  • Denitration catalyst layer 13 that oxidizes mercury (Hg) by spraying hydrogen chloride (HCl) as an agent, air preheater 14 that recovers heat in exhaust gas 12 after nitrogen oxide (NOx) removal, and heat recovery
  • An electric precipitator 15 that removes soot and dust in the exhaust gas 12 after
  • a desulfurization device 16 that removes sulfur oxide (SOx) and mercury (Hg) in the exhaust gas 12 after dust removal, and purification of the exhaust gas 12 after desulfurization
  • a chimney 18 that is discharged to the outside as the gas 17 is provided.
  • the flue 19 on the upstream side of the denitration catalyst layer 13 is provided with an injection site of hydrochloric acid (HCl), and the hydrochloric acid (liquid) stored in the hydrochloric acid (liquid HCl) supply unit 20 is sprayed with hydrogen chloride. Vaporized in the section 21 and sprayed as hydrogen chloride on the exhaust gas 12 through a hydrogen chloride (HCl) spray nozzle.
  • HCl hydrogen chloride
  • an ammonia (NH 3 ) injection point is provided in the upstream flue 19 of the denitration catalyst layer 13, and ammonia supplied from the NH 3 supply unit 29 is sprayed on the exhaust gas 12 by an ammonia spray nozzle. Nitrogen oxide (NOx) is reduced.
  • reference numeral 25 denotes an oxidation-reduction potential measurement control device (ORP controller), and 26 denotes air.
  • the exhaust gas 12 from the coal-fired boiler 11 is supplied to the denitration catalyst layer 13 and then heated to the air preheater 14 by heat exchange, and then supplied to the electrostatic precipitator 15 and further desulfurized. After being supplied to the device 16, it is discharged to the atmosphere as purified gas 17.
  • the mercury concentration of exhaust gas after wet desulfurization is measured with a mercury monitor, and based on the mercury concentration after desulfurization, the chlorinating agent The supply amount is adjusted (for example, see Patent Document 2).
  • NH 3 is used for the reduction denitration of NOx
  • NH 3 ammonia (NH 3) supplied from the NH 3 supply unit 29 via the spray nozzle is sprayed into the flue gas 12, in the denitration catalyst layer 13, the following formula As described above, NOx is replaced by nitrogen (N 2 ) by a reduction reaction, and denitration is performed.
  • NOx is replaced by nitrogen (N 2 ) by a reduction reaction, and denitration is performed.
  • hydrogen chloride is used for mercury oxidation, and hydrogen chloride used as a chlorinating agent is supplied from an HCl supply unit 20 to a hydrogen chloride (HCl) spray unit 21 where hydrochloric acid is vaporized and hydrogen chloride (HCl) is supplied.
  • HCl hydrogen chloride
  • the denitration catalyst layer 13 oxidizes (chlorinates) low-solubility Hg on the denitration catalyst as shown in the following formula, and has high water-soluble mercury chloride. It is converted to (HgCl 2 ), and Hg contained in the exhaust gas 12 is removed by the desulfurization device 16 provided on the downstream side.
  • the fuel when coal or heavy oil is used as the fuel, the fuel contains Cl because the fuel contains Cl, but the Cl content is different depending on the type of fuel, and the Cl concentration in the exhaust gas is different. Since it is difficult to control the amount of HCl, it is preferable that Hg is reliably removed by adding more than a necessary amount of HCl or the like to the upstream of the exhaust gas treatment apparatus 10.
  • the denitration catalyst layer 13 uses, for example, a honeycomb shape having a rectangular passage 28 arranged in a lattice and carrying a denitration catalyst, and the cross-sectional shape of the passage is, for example, a triangular shape or a square shape.
  • the passage is made up of polygonal shapes.
  • an object of the present invention is to provide an exhaust gas treatment apparatus and an exhaust gas treatment system that can always stably perform oxidation performance of mercury in exhaust gas.
  • the first invention of the present invention for solving the above-described problem has a denitration catalyst unit that removes nitrogen oxides in exhaust gas from a boiler and oxidizes mercury by spraying a chlorinating agent into the exhaust gas.
  • the supply position for supplying the chlorinating agent is in the exhaust gas treatment apparatus characterized in that the cross-sectional shape of the upstream-side flue of the denitration catalyst part is a uniform part in the axial direction. .
  • the exhaust gas processing apparatus according to the first aspect, wherein the portion having a uniform cross-sectional shape is a vertical portion of a front-side flue of the denitration catalyst portion.
  • the boiler a chlorinating agent supply unit for injecting a chlorinating agent into the exhaust gas discharged to the flue downstream of the boiler, the first or second exhaust gas treatment device,
  • An exhaust gas treatment system having a desulfurization device for removing sulfur oxides in exhaust gas and a chimney for discharging the desulfurized gas to the outside.
  • an exhaust gas treatment system according to the third aspect of the present invention, further comprising an ammonia supply unit for introducing ammonia to the exhaust gas discharged to the flue downstream of the boiler.
  • the chlorinating agent can be supplied regardless of the exhaust gas flow conditions, and the required mercury oxidation performance can be ensured.
  • FIG. 1 is a schematic view showing an exhaust gas treatment apparatus according to an embodiment of the present invention.
  • FIG. 2 is a perspective view showing a part of the configuration of the denitration catalyst layer.
  • FIG. 3 is a relationship diagram between the hydrogen chloride concentration and the mercury oxidation rate depending on the hydrogen chloride charging position according to the test example of the present invention.
  • FIG. 4 is a graph showing the relationship between the hydrogen chloride concentration and the mercury oxidation rate depending on the hydrogen chloride charging position according to the comparative example of the present invention.
  • FIG. 5 is a schematic diagram of an exhaust gas treatment system for a coal fired boiler.
  • FIG. 1 is a schematic diagram illustrating an exhaust gas treatment apparatus according to an embodiment
  • FIG. 2 is a perspective view illustrating a part of the configuration of the exhaust gas treatment apparatus according to the embodiment.
  • description will be made by taking hydrogen chloride as an example of the chlorinating agent. 1 is a part of the exhaust gas treatment system shown in FIG.
  • the exhaust gas treatment apparatus 10 removes nitrogen oxides (NOx) in the exhaust gas 12 from the boiler 11, and the chlorinating agent in the exhaust gas 12
  • the supply position for supplying the chlorinating agent is an exhaust gas flue (hereinafter referred to as “smoke” on the upstream side of the denitration catalyst part. (Referred to as hydrogen chloride supply region 41 in FIG. 1).
  • the denitration catalyst layer 13 is formed of three catalyst layers 13-1 to 13-3, but the present invention is not limited to this.
  • a rectifying plate 30 for rectifying the exhaust gas 12 after hydrogen chloride is supplied is disposed on the upstream side of the denitration catalyst layer 13 so that the exhaust gas 12 supplied to the catalyst is rectified.
  • the distance 42 from the ammonia (NH 3 ) charging position to the ammonia side of the hydrogen chloride supply region 41 is at least 3 m or more. This is to prevent mixing of hydrogen chloride and ammonia.
  • FIG. 2 is a perspective view of FIG. 1, but the rectifying plate 30 disposed on the upstream side of the denitration catalyst layer 13 is omitted.
  • a first monitoring unit 31 (31a to 31d) that measures at least one of exhaust gas temperature, exhaust gas flow velocity distribution, and hydrogen chloride concentration distribution
  • a second monitoring unit 32 (32a, 32b) that measures the amount of mercury in the exhaust gas is disposed on the outlet side of the denitration catalyst layer 13, and the first monitoring unit 31 and the second monitoring unit 32 According to the result, the spray amount of hydrogen chloride is adjusted.
  • the flue 19 has a rectangular cross section, for example, 3 m ⁇ 12 m.
  • hydrogen chloride is supplied from countless (500 or more) nozzles provided in a hydrogen chloride supply pipe extending in the longitudinal direction of the cross section of the flue 19. I try to spray.
  • the operating conditions of the exhaust gas treatment device 10 exhaust gas temperature, exhaust gas flow velocity distribution, hydrogen chloride concentration distribution in the exhaust gas
  • the degree of variation thereof are monitored by the first monitoring unit 31, and those values are monitored by the central processing unit ( CPU), and the required mercury oxidation performance may be ensured by adjusting the amount of hydrogen chloride and the exhaust gas temperature accordingly.
  • FIG. 3 is a graph showing the relationship between the hydrogen chloride concentration and the mercury oxidation rate at the hydrogen chloride charging position (any one of the hydrogen chloride supply regions 41) according to the test example of the present invention. Was not seen.
  • FIG. 4 as shown in the hydrogen chloride charging position according to the comparative example (the flue bend 43 on the upstream side of the hydrogen chloride supply region 41 shown in FIG. 1), the mercury in the exhaust gas. There was variation in the oxidation rate.
  • the mercury oxidation rate 400 sensors were provided as the first monitoring unit 31 on the inlet side of the denitration catalyst layer 13, and the variation of the mercury oxidation rate in the cross section was measured.
  • the predetermined concentration (X) may be 200 to 500 ppm, but the present invention is not limited to this.
  • the supply position for supplying the chlorinating agent is the region 41 where the cross-sectional shape of the upstream-side flue 19 of the denitration catalyst layer is uniform over the axial direction.
  • metal oxides such as V, W, Mo, Ni, Co, Fe, Cr, Mn, and Cu are used as the denitration catalyst used in the denitration catalyst layer 13 for reducing denitration.
  • a sulfate, or a noble metal such as Pt, Ru, Rh, Pd, Ir, or a mixture thereof supported on titania, silica, zirconia and a composite oxide thereof, or zeolite can be used. .
  • the concentration of HCl to be used is not particularly limited.
  • dilute hydrochloric acid of about 5% from concentrated hydrochloric acid can be used.
  • hydrogen chloride (HCl) was used as the chlorinating agent to be used.
  • Hg in the exhaust gas is a denitration catalyst.
  • HgCl and / or HgCl 2 mercury chloride As long as it produces HgCl and / or HgCl 2 mercury chloride.
  • both HCl and NH 3 are added to the exhaust gas 12 discharged from the boiler 11, but NH 3 may not be added to the exhaust gas 12 in the flue 19.
  • the denitration catalyst layer 13 of the exhaust gas treatment device 10 removes NOx (nitrogen oxides) in the exhaust gas 12 and oxidizes Hg in the exhaust gas 12, and Hg is removed by a desulfurization device (not shown) provided on the downstream side. Since it is to be removed, even if NH 3 is not added to the exhaust gas 12 in the flue 19, Hg is converted to chloride with HCl in the presence of the denitration catalyst in the denitration catalyst layer 13, and a desulfurization apparatus (not shown) This is because the effect of removing Hg does not change.
  • the exhaust gas discharged from the boiler of the thermal power plant that burns fossil fuel containing sulfur, mercury, etc. such as coal and heavy oil is described, but the present invention is not limited to this. NOx concentration is low, boiler exhaust gas emitted from a factory that burns fuel containing carbon dioxide, oxygen, SOx, dust, or moisture, fuel containing sulfur, mercury, etc., metal factory, oil refinery factory, petrochemical It can also be applied to furnace exhaust gas discharged from factories and the like.
  • the operating conditions of the actual machine and the degree of variation thereof are monitored, and the spray amount of hydrogen chloride is adjusted accordingly, The required mercury performance can be ensured.
  • the supply position for supplying the chlorinating agent is a section where the cross-sectional shape of the upstream-side flue of the denitration catalyst part is uniform over the axial direction. Since the required mercury performance can be ensured, it is suitable for use in the treatment of exhaust gas discharged from an apparatus that burns fossil fuels such as coal and heavy oil containing mercury such as thermal power plants.

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Abstract

An apparatus for discharge gas treatment is provided which includes a denitration catalyst layer (13) in which nitrogen oxides (NOx) contained in a discharge gas (12) discharged from a boiler (11) are removed and hydrogen chloride as a chlorinating agent is sprayed in the discharge gas (12) to oxidize mercury (Hg).  In the apparatus, the chlorinating agent is supplied to that area of a discharge gas flue (19) which is located upstream from the denitration catalyst part and has the same sectional shape throughout the axis direction (anywhere in a hydrogen chloride supply region (41)).  Desired mercury-removing performance can be ensured.  This apparatus can be used in treating the discharge gas discharged from an apparatus which burns a mercury-containing fossil fuel such as coal or heavy oil, as in thermal power stations.

Description

排ガス処理装置及び排ガス処理システムExhaust gas treatment apparatus and exhaust gas treatment system
　本発明は、燃焼装置から排出される排ガスの水銀の酸化処理を行う排ガス処理装置及び排ガス処理システムに関する。 The present invention relates to an exhaust gas treatment device and an exhaust gas treatment system for oxidizing mercury in exhaust gas discharged from a combustion device.
　例えば火力発電所等の燃焼装置である石炭焚ボイラから排出される排ガスには毒性の高い水銀が含まれるため、従来から排ガス中の水銀を除去するためのシステムが種々検討されてきた。 For example, since exhaust gas discharged from a coal fired boiler, which is a combustion apparatus such as a thermal power plant, contains highly toxic mercury, various systems for removing mercury in the exhaust gas have been studied.
　通常、石炭焚ボイラには排ガス中の硫黄分を除去するための湿式の脱硫装置が設けられている。このようなボイラに排ガス処理装置として脱硫装置が付設されてなる排煙処理設備においては、排ガス中の塩素（Ｃｌ）分が多くなると、水に可溶な２価の金属水銀（Ｈｇ）の割合が多くなり、前記脱硫装置で水銀が捕集しやすくなることが、広く知られている。 Usually, coal fired boilers are provided with a wet desulfurization device for removing sulfur content in the exhaust gas. In a flue gas treatment facility in which a desulfurization device is attached to such a boiler as an exhaust gas treatment device, when the chlorine (Cl) content in the exhaust gas increases, the proportion of divalent metal mercury (Hg) soluble in water It is widely known that mercury tends to be collected by the desulfurization apparatus.
　そのため、近年、ＮＯｘを還元する脱硝触媒層、および、アルカリ吸収液を硫黄酸化物（ＳＯｘ）吸収剤とする湿式脱硫装置と組み合わせて、この金属水銀を処理する方法や装置について様々な考案がなされてきた。 Therefore, in recent years, various devices and methods for treating this metallic mercury have been devised in combination with a denitration catalyst layer for reducing NOx and a wet desulfurization apparatus using an alkali absorbent as a sulfur oxide (SOx) absorbent. I came.
　排ガス中の金属水銀を処理する方法としては、活性炭やセレンフィルター等の吸着剤による除去方法が知られているが、特殊な吸着除去手段が必要であり、発電所排ガス等の大容量排ガスの処理には適していない。 As a method for treating metallic mercury in exhaust gas, a removal method using an adsorbent such as activated carbon or a selenium filter is known. However, a special adsorption removal means is required, and a large-capacity exhaust gas such as power plant exhaust gas is treated. Not suitable for.
　そこで、大容量排ガス中の金属水銀を処理する方法として、煙道中、高温の脱硝触媒層の前流工程で塩素化剤をガス噴霧し、脱硝触媒上で水銀を酸化（塩素化）させ、水溶性の塩化水銀にした後、後流の湿式脱硫装置で吸収させる方法が提案されている（例えば、特許文献１及び特許文献２、参照）。また、煙道にガス噴霧する装置および技術は脱硝触媒層のＮＨ3噴霧、塩素化剤のガス噴霧で実用化されている。 Therefore, as a method of treating metal mercury in large-capacity exhaust gas, a chlorinating agent is gas-sprayed in the upstream process of the high-temperature denitration catalyst layer in the flue, and mercury is oxidized (chlorinated) on the denitration catalyst to produce water. A method is proposed in which the product is converted to a characteristic mercury chloride and then absorbed by a downstream wet desulfurization apparatus (see, for example, Patent Document 1 and Patent Document 2). In addition, an apparatus and a technique for spraying a gas to a flue are put into practical use by NH 3 spraying of a denitration catalyst layer and gas spraying of a chlorinating agent.
　石炭焚きボイラの排ガス処理システムの概略図を図５に示す。図５に示すように、従来の排ガス処理システム１００は、燃料Ｆとして石炭を供給する石炭焚きのボイラ１１からの排ガス１２中の窒素酸化物（ＮＯｘ）を除去すると共に、排ガス１２中に塩素化剤である塩化水素（ＨＣｌ）を噴霧して水銀（Ｈｇ）を酸化する脱硝触媒層１３と、窒素酸化物（ＮＯｘ）除去後の排ガス１２中の熱を回収する空気予熱器１４と、熱回収後の排ガス１２中の煤塵を除去する電気集塵器１５と、除塵後の排ガス１２中の硫黄酸化物（ＳＯｘ）、水銀（Ｈｇ）を除去する脱硫装置１６と、脱硫後の排ガス１２を浄化ガス１７として外部に排出する煙突１８とを具備するものである。 Fig. 5 shows a schematic diagram of an exhaust gas treatment system for a coal fired boiler. As shown in FIG. 5, the conventional exhaust gas treatment system 100 removes nitrogen oxide (NOx) in the exhaust gas 12 from the coal-fired boiler 11 that supplies coal as the fuel F, and chlorinates in the exhaust gas 12. Denitration catalyst layer 13 that oxidizes mercury (Hg) by spraying hydrogen chloride (HCl) as an agent, air preheater 14 that recovers heat in exhaust gas 12 after nitrogen oxide (NOx) removal, and heat recovery An electric precipitator 15 that removes soot and dust in the exhaust gas 12 after, a desulfurization device 16 that removes sulfur oxide (SOx) and mercury (Hg) in the exhaust gas 12 after dust removal, and purification of the exhaust gas 12 after desulfurization A chimney 18 that is discharged to the outside as the gas 17 is provided.
　また、脱硝触媒層１３の前流の煙道１９には、塩酸（ＨＣｌ）の注入箇所が設けられており、塩酸（液体ＨＣｌ）供給部２０に貯蔵された塩酸（液体）は、塩化水素噴霧部２１で気化して塩化水素（ＨＣｌ）噴霧ノズルを介して塩化水素として排ガス１２に噴霧されている。 The flue 19 on the upstream side of the denitration catalyst layer 13 is provided with an injection site of hydrochloric acid (HCl), and the hydrochloric acid (liquid) stored in the hydrochloric acid (liquid HCl) supply unit 20 is sprayed with hydrogen chloride. Vaporized in the section 21 and sprayed as hydrogen chloride on the exhaust gas 12 through a hydrogen chloride (HCl) spray nozzle.
　また、脱硝触媒層１３の前流の煙道１９には、アンモニア（ＮＨ3）の注入箇所が設けられており、ＮＨ3供給部２９から供給されるアンモニアはアンモニア噴霧ノズルにより排ガス１２に噴霧し、窒素酸化物（ＮＯｘ）の還元を行うようにしている。
　なお、図５中、符号２５は酸化還元電位測定制御装置（ＯＲＰコントローラ）、２６は空気を各々図示する。 In addition, an ammonia (NH 3 ) injection point is provided in the upstream flue 19 of the denitration catalyst layer 13, and ammonia supplied from the NH 3 supply unit 29 is sprayed on the exhaust gas 12 by an ammonia spray nozzle. Nitrogen oxide (NOx) is reduced.
In FIG. 5, reference numeral 25 denotes an oxidation-reduction potential measurement control device (ORP controller), and 26 denotes air.
　ここで、石炭焚きのボイラ１１からの排ガス１２は、脱硝触媒層１３に供給され、その後空気予熱器１４で熱交換により空気２７を加熱した後、電気集塵器１５に供給され、更に、脱硫装置１６に供給された後、浄化ガス１７として大気に排出される。 Here, the exhaust gas 12 from the coal-fired boiler 11 is supplied to the denitration catalyst layer 13 and then heated to the air preheater 14 by heat exchange, and then supplied to the electrostatic precipitator 15 and further desulfurized. After being supplied to the device 16, it is discharged to the atmosphere as purified gas 17.
　また、塩素化剤による装置への腐食破損等の影響を抑え信頼性を向上させるため、湿式脱硫後の排ガスについて水銀濃度を水銀モニターで測定し、脱硫後の水銀濃度に基づいて塩素化剤の供給量を調整するようにしている（例えば、特許文献２、参照）。 In addition, in order to improve the reliability by suppressing the influence of corrosion damage to the equipment by the chlorinating agent, the mercury concentration of exhaust gas after wet desulfurization is measured with a mercury monitor, and based on the mercury concentration after desulfurization, the chlorinating agent The supply amount is adjusted (for example, see Patent Document 2).
　このように、従来においては、排ガス１２中に塩化水素とアンモニアとを供給することで、排ガス１２中のＮＯｘ（窒素酸化物）を除去すると共に、排ガス１２中の水銀（Ｈｇ）を酸化するようにしている。 Thus, conventionally, by supplying hydrogen chloride and ammonia into the exhaust gas 12, NOx (nitrogen oxide) in the exhaust gas 12 is removed and mercury (Hg) in the exhaust gas 12 is oxidized. I have to.
　即ち、ＮＨ3はＮＯｘの還元脱硝用に用い、ＮＨ3供給部２９から供給されるＮＨ3をアンモニア（ＮＨ3）噴霧ノズルを介して排ガス１２中に噴霧し、脱硝触媒層１３で、下記式のように還元反応によりＮＯｘを窒素（Ｎ2）に置換し、脱硝するようにしている。
４ＮＯ　＋　４ＮＨ3　＋　Ｏ2　→　４Ｎ2　＋　６Ｈ2Ｏ・・・（１）
ＮＯ　＋　ＮＯ2　＋　２ＮＨ3　→　２Ｎ2　＋　３Ｈ2Ｏ・・・（２） That, NH 3 is used for the reduction denitration of NOx, NH 3 ammonia (NH 3) supplied from the NH 3 supply unit 29 via the spray nozzle is sprayed into the flue gas 12, in the denitration catalyst layer 13, the following formula As described above, NOx is replaced by nitrogen (N 2 ) by a reduction reaction, and denitration is performed.
4NO + 4NH 3 + O 2 → 4N 2 + 6H 2 O (1)
NO + NO 2 + 2NH 3 → 2N 2 + 3H 2 O (2)
　また、塩化水素は水銀酸化用に用いており、塩素化剤として用いられる塩化水素はＨＣｌ供給部２０から塩化水素（ＨＣｌ）噴霧部２１に供給され、ここで塩酸は気化され、塩化水素（ＨＣｌ）として塩化水素噴霧ノズル２１ａにより排ガス１２中に噴霧することで、脱硝触媒層１３において、下記式のように脱硝触媒上で溶解度の低いＨｇを酸化(塩素化)し、水溶性の高い塩化水銀（ＨｇＣｌ2）に変換させ、後流側に設けられる脱硫装置１６で排ガス１２中に含有するＨｇを除去するようにしている。
Ｈｇ　＋　２ＨＣｌ　＋　１／２Ｏ2　→　ＨｇＣｌ2　＋　Ｈ2Ｏ・・・（３） Further, hydrogen chloride is used for mercury oxidation, and hydrogen chloride used as a chlorinating agent is supplied from an HCl supply unit 20 to a hydrogen chloride (HCl) spray unit 21 where hydrochloric acid is vaporized and hydrogen chloride (HCl) is supplied. ) By spraying into the exhaust gas 12 by the hydrogen chloride spray nozzle 21a, the denitration catalyst layer 13 oxidizes (chlorinates) low-solubility Hg on the denitration catalyst as shown in the following formula, and has high water-soluble mercury chloride. It is converted to (HgCl 2 ), and Hg contained in the exhaust gas 12 is removed by the desulfurization device 16 provided on the downstream side.
Hg + 2HCl + 1 / 2O 2 → HgCl 2 + H 2 O (3)
　また、燃料として石炭又は重油を使用した場合、燃料中にはＣｌが含まれるため燃焼ガス１２にはＣｌ分が含まれるが、燃料の種類によりＣｌ分の含有量は異なり、排ガス中のＣｌ濃度を制御するのは困難であるため、排ガス処理装置１０の前流に必要量以上のＨＣｌ等を添加し、確実にＨｇを除去するようにするのが好ましい。 In addition, when coal or heavy oil is used as the fuel, the fuel contains Cl because the fuel contains Cl, but the Cl content is different depending on the type of fuel, and the Cl concentration in the exhaust gas is different. Since it is difficult to control the amount of HCl, it is preferable that Hg is reliably removed by adding more than a necessary amount of HCl or the like to the upstream of the exhaust gas treatment apparatus 10.
　また、脱硝触媒層１３は、例えば格子状に配列して四角形状の通路２８を有するハニカム形状のものに脱硝触媒を担持したものを用いており、その通路の断面形状は例えば三角形状や四角形状など多角形状からなる通路としている。 Further, the denitration catalyst layer 13 uses, for example, a honeycomb shape having a rectangular passage 28 arranged in a lattice and carrying a denitration catalyst, and the cross-sectional shape of the passage is, for example, a triangular shape or a square shape. The passage is made up of polygonal shapes.
特開平１０－２３０１３７号公報Japanese Patent Laid-Open No. 10-230137 特開２００１－１９８４３４号公報JP 2001-198434 A
　ところで、従来のボイラ１１からの排ガス１２の気流は、偏流となっており、塩化水素を供給する位置により、脱硝触媒部に均一な塩化水素の供給ができなくなり、水銀酸化性能にバラツキが生じる場合がある。
　この結果、排ガス中の水銀の酸化性能が低下するという問題がある。
　よって、排ガスの気流の条件によらず、所要の水銀酸化性能を達成できることが切望されている。 By the way, the flow of the exhaust gas 12 from the conventional boiler 11 is unevenly distributed, and it becomes impossible to uniformly supply hydrogen chloride to the denitration catalyst portion depending on the position where hydrogen chloride is supplied, resulting in variations in mercury oxidation performance. There is.
As a result, there is a problem that the oxidation performance of mercury in the exhaust gas is lowered.
Therefore, it is anxious to be able to achieve the required mercury oxidation performance regardless of the conditions of the exhaust gas flow.
　本発明は、前記問題に鑑み、排ガス中の水銀の酸化性能を常に安定して行うことができる排ガス処理装置及び排ガス処理システムを提供することを課題とする。 In view of the above problems, an object of the present invention is to provide an exhaust gas treatment apparatus and an exhaust gas treatment system that can always stably perform oxidation performance of mercury in exhaust gas.
　上述した課題を解決するための本発明の第１の発明は、ボイラからの排ガス中の窒素酸化物を除去すると共に、排ガス中に塩素化剤を噴霧して水銀を酸化する脱硝触媒部を有する排ガス処理装置において、前記塩素化剤を供給する供給位置は、脱硝触媒部の前流側煙道の断面形状が軸方向に亙って均一な部分とすることを特徴とする排ガス処理装置にある。 The first invention of the present invention for solving the above-described problem has a denitration catalyst unit that removes nitrogen oxides in exhaust gas from a boiler and oxidizes mercury by spraying a chlorinating agent into the exhaust gas. In the exhaust gas treatment apparatus, the supply position for supplying the chlorinating agent is in the exhaust gas treatment apparatus characterized in that the cross-sectional shape of the upstream-side flue of the denitration catalyst part is a uniform part in the axial direction. .
　第２の発明は、第１の発明において、前記断面形状が均一な部分は、脱硝触媒部の前流側煙道の鉛直部であることを特徴とする排ガス処理装置にある。 According to a second aspect of the present invention, there is provided the exhaust gas processing apparatus according to the first aspect, wherein the portion having a uniform cross-sectional shape is a vertical portion of a front-side flue of the denitration catalyst portion.
　第３の発明は、前記ボイラと、前記ボイラの下流側の煙道に排出された排ガスに塩素化剤を注入する塩素化剤供給部と、第１又は２の排ガス処理装置と、脱硝後の排ガス中の硫黄酸化物を除去する脱硫装置と、脱硫後のガスを外部に排出する煙突とを有することを特徴とする排ガス処理システムにある。 According to a third aspect of the present invention, there is provided the boiler, a chlorinating agent supply unit for injecting a chlorinating agent into the exhaust gas discharged to the flue downstream of the boiler, the first or second exhaust gas treatment device, An exhaust gas treatment system having a desulfurization device for removing sulfur oxides in exhaust gas and a chimney for discharging the desulfurized gas to the outside.
　第４の発明は、第３の発明において、前記ボイラの下流側の煙道に排出された排ガスにアンモニアを投入するアンモニア供給部が設けられてなることを特徴とする排ガス処理システムにある。 According to a fourth aspect of the present invention, there is provided an exhaust gas treatment system according to the third aspect of the present invention, further comprising an ammonia supply unit for introducing ammonia to the exhaust gas discharged to the flue downstream of the boiler.
　本発明によれば、排ガスの気流条件によらず、塩素化剤を供給することができ、所要の水銀酸化性能を確保することができる。 According to the present invention, the chlorinating agent can be supplied regardless of the exhaust gas flow conditions, and the required mercury oxidation performance can be ensured.
図１は、本発明の実施例に係る排ガス処理装置を示す概略図である。FIG. 1 is a schematic view showing an exhaust gas treatment apparatus according to an embodiment of the present invention. 図２は、脱硝触媒層の構成の一部を示す斜視図である。FIG. 2 is a perspective view showing a part of the configuration of the denitration catalyst layer. 図３は、本発明の試験例にかかる塩化水素の投入位置による塩化水素濃度と水銀酸化率との関係図である。FIG. 3 is a relationship diagram between the hydrogen chloride concentration and the mercury oxidation rate depending on the hydrogen chloride charging position according to the test example of the present invention. 図４は、本発明の比較例にかかる塩化水素の投入位置による塩化水素濃度と水銀酸化率との関係図である。FIG. 4 is a graph showing the relationship between the hydrogen chloride concentration and the mercury oxidation rate depending on the hydrogen chloride charging position according to the comparative example of the present invention. 図５は、石炭焚ボイラの排ガス処理システムの概略図である。FIG. 5 is a schematic diagram of an exhaust gas treatment system for a coal fired boiler.
　以下、この発明につき図面を参照しつつ詳細に説明する。なお、この実施例によりこの発明が限定されるものではない。また、下記実施例における構成要素には、当業者が容易に想定できるもの、あるいは実質的に同一のものが含まれる。 Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.
　本発明による実施例に係る排ガス処理装置を適用した排ガス処理システムについて、図面を参照して説明する。
　なお、本実施例に係る排ガス処理装置を適用した排ガス処理システムの構成は、図５に示す排ガス処理システムの構成と同様であるため、本実施例においては、排ガス処理装置の構成のみについて説明する。
　図１は、実施例に係る排ガス処理装置を示す概略図であり、図２は、実施例に係る排ガス処理装置の構成の一部を示す斜視図である。ここで、本実施例では塩素化剤として塩化水素を例にして説明する。なお、図１の構成は、図５に示す排ガス処理システムの一部であるので、従来の構成と同一部材には同一符号を付して重複した説明は省略する。
　図１及び図２に示すように、本実施例に係る排ガス処理装置１０は、ボイラ１１からの排ガス１２中の窒素酸化物（ＮＯｘ）を除去すると共に、排ガス１２中に塩素化剤である塩化水素を噴霧して水銀（Ｈｇ）を酸化する脱硝触媒層１３を有する排ガス処理装置において、前記塩素化剤を供給する供給位置は、脱硝触媒部の前流側の排ガス煙道（以下、「煙道」という）１９の断面形状が軸方向に亙って均一な部分（図１中、塩化水素供給領域４１のいずれか）としている。 An exhaust gas treatment system to which an exhaust gas treatment apparatus according to an embodiment of the present invention is applied will be described with reference to the drawings.
The configuration of the exhaust gas treatment system to which the exhaust gas treatment device according to the present embodiment is applied is the same as the configuration of the exhaust gas treatment system shown in FIG. 5, and therefore, in this embodiment, only the configuration of the exhaust gas treatment device will be described. .
FIG. 1 is a schematic diagram illustrating an exhaust gas treatment apparatus according to an embodiment, and FIG. 2 is a perspective view illustrating a part of the configuration of the exhaust gas treatment apparatus according to the embodiment. Here, in this embodiment, description will be made by taking hydrogen chloride as an example of the chlorinating agent. 1 is a part of the exhaust gas treatment system shown in FIG. 5, the same members as those in the conventional configuration are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIGS. 1 and 2, the exhaust gas treatment apparatus 10 according to the present embodiment removes nitrogen oxides (NOx) in the exhaust gas 12 from the boiler 11, and the chlorinating agent in the exhaust gas 12 In the exhaust gas treatment apparatus having the denitration catalyst layer 13 that sprays hydrogen to oxidize mercury (Hg), the supply position for supplying the chlorinating agent is an exhaust gas flue (hereinafter referred to as “smoke” on the upstream side of the denitration catalyst part. (Referred to as hydrogen chloride supply region 41 in FIG. 1).
　この結果、排ガス１２の気流条件によらず、塩素化剤である塩化水素を供給することができ、脱硝触媒層１３において、所要の水銀酸化性能を確保することができる。
　なお、本実施例においては、脱硝触媒層１３は３層の触媒層１３－１～１３－３から形成されているが、本発明はこれに限定されるものではない。本実施例では、脱硝触媒層１３の前流側に塩化水素が供給された後の排ガス１２を整流する整流板３０を配置して、触媒に供給する排ガス１２を整流化するようにしている。 As a result, hydrogen chloride, which is a chlorinating agent, can be supplied regardless of the airflow conditions of the exhaust gas 12, and the required mercury oxidation performance can be ensured in the denitration catalyst layer 13.
In this embodiment, the denitration catalyst layer 13 is formed of three catalyst layers 13-1 to 13-3, but the present invention is not limited to this. In this embodiment, a rectifying plate 30 for rectifying the exhaust gas 12 after hydrogen chloride is supplied is disposed on the upstream side of the denitration catalyst layer 13 so that the exhaust gas 12 supplied to the catalyst is rectified.
　また、図１に示すように、アンモニア（ＮＨ3）投入位置から、塩化水素供給領域４１のアンモニア側との距離４２は、少なくとも３ｍ以上離すようにすることが好ましい。
　これは、塩化水素とアンモニアとの混合を防止するためである。 As shown in FIG. 1, it is preferable that the distance 42 from the ammonia (NH 3 ) charging position to the ammonia side of the hydrogen chloride supply region 41 is at least 3 m or more.
This is to prevent mixing of hydrogen chloride and ammonia.
　ここで、図２においては、図１の斜視図であるが、脱硝触媒層１３の前流側に配置した整流板３０は省略している。ここで、図２において、前記脱硝触媒層１３の入口側において、排ガスの温度、排ガスの流速分布、塩化水素濃度分布の少なくとも一以上を計測する第１のモニタリング部３１（３１ａ～３１ｄ）と、前記脱硝触媒層１３の出口側において、排ガス中の水銀量を計測する第２のモニタリング部３２（３２ａ、３２ｂ）を配設しており、第１のモニタリング部３１と第２のモニタリング部３２との結果により、塩化水素の噴霧量を調整するようにしている。
　なお、煙道１９は断面が矩形状としており、例えば３ｍ×１２ｍとしている。
　このような矩形状の煙道１９に塩化水素を供給するノズル供給部としては、煙道１９の断面長手方向に延びる塩化水素供給管に設けた無数（５００個以上）のノズルから、塩化水素を噴霧するようにしている。 Here, FIG. 2 is a perspective view of FIG. 1, but the rectifying plate 30 disposed on the upstream side of the denitration catalyst layer 13 is omitted. Here, in FIG. 2, on the inlet side of the denitration catalyst layer 13, a first monitoring unit 31 (31a to 31d) that measures at least one of exhaust gas temperature, exhaust gas flow velocity distribution, and hydrogen chloride concentration distribution; A second monitoring unit 32 (32a, 32b) that measures the amount of mercury in the exhaust gas is disposed on the outlet side of the denitration catalyst layer 13, and the first monitoring unit 31 and the second monitoring unit 32 According to the result, the spray amount of hydrogen chloride is adjusted.
The flue 19 has a rectangular cross section, for example, 3 m × 12 m.
As a nozzle supply part for supplying hydrogen chloride to such a rectangular flue 19, hydrogen chloride is supplied from countless (500 or more) nozzles provided in a hydrogen chloride supply pipe extending in the longitudinal direction of the cross section of the flue 19. I try to spray.
　さらに、排ガス処理装置１０の運転条件（排ガス温度、排ガスの流速分布、排ガス中の塩化水素濃度分布）や、そのバラツキ度合いを第１のモニタリング部３１でモニタリングし、それらの値を中央演算装置（ＣＰＵ）で演算し、それらに応じて塩化水素量や排ガス温度を調整することにより、所要の水銀酸化性能を確保するようにしてもよい。 Further, the operating conditions of the exhaust gas treatment device 10 (exhaust gas temperature, exhaust gas flow velocity distribution, hydrogen chloride concentration distribution in the exhaust gas) and the degree of variation thereof are monitored by the first monitoring unit 31, and those values are monitored by the central processing unit ( CPU), and the required mercury oxidation performance may be ensured by adjusting the amount of hydrogen chloride and the exhaust gas temperature accordingly.
　図３は、本発明の試験例にかかる塩化水素の投入位置（塩化水素供給領域４１のいずれか）による塩化水素濃度と水銀酸化率との関係図であり、排ガス中の水銀酸化率におおきなバラツキはみられなかった。
　これに対し、図４に示すように、比較例にかかる塩化水素の投入位置（図１に示す塩化水素供給領域４１の前流側で煙道屈曲部４３）に示すように、排ガス中の水銀酸化率にバラツキはみられた。 FIG. 3 is a graph showing the relationship between the hydrogen chloride concentration and the mercury oxidation rate at the hydrogen chloride charging position (any one of the hydrogen chloride supply regions 41) according to the test example of the present invention. Was not seen.
On the other hand, as shown in FIG. 4, as shown in the hydrogen chloride charging position according to the comparative example (the flue bend 43 on the upstream side of the hydrogen chloride supply region 41 shown in FIG. 1), the mercury in the exhaust gas. There was variation in the oxidation rate.
　ここで、水銀酸化率は脱硝触媒層１３の入口側において、第１のモニタリング部３１として、４００個のセンサを設けて、断面における水銀酸化率のバラツキを計測した。 Here, as for the mercury oxidation rate, 400 sensors were provided as the first monitoring unit 31 on the inlet side of the denitration catalyst layer 13, and the variation of the mercury oxidation rate in the cross section was measured.
　ここで、運転条件により、所定濃度（Ｘ）としては、２００～５００ｐｐｍとすればよいが、本発明はこれに限定されるものではない。 Here, depending on the operating conditions, the predetermined concentration (X) may be 200 to 500 ppm, but the present invention is not limited to this.
　このように、本発明によれば、前記塩素化剤を供給する供給位置は、脱硝触媒層の前流側煙道１９の断面形状が軸方向に亙って均一な部分の領域４１とすることで、ボイラからの排ガスの気流条件が変動しても常に安定して高い水銀酸化性能（例えば９５％以上）を確保することができるものとなる。 Thus, according to the present invention, the supply position for supplying the chlorinating agent is the region 41 where the cross-sectional shape of the upstream-side flue 19 of the denitration catalyst layer is uniform over the axial direction. Thus, even when the airflow conditions of the exhaust gas from the boiler fluctuate, it is possible to ensure a stable and high mercury oxidation performance (for example, 95% or more).
　ここで、本実施例に係る排ガス処理装置１０においては、還元脱硝用に脱硝触媒層１３で用いる脱硝触媒として、Ｖ、Ｗ、Ｍｏ、Ｎｉ、Ｃｏ、Ｆｅ、Ｃｒ、Ｍｎ、Ｃｕ等の金属酸化物又は硫酸塩あるいは、Ｐｔ、Ｒｕ、Ｒｈ、Ｐｄ、Ｉｒなどの貴金属、又はこれらの混合物を担体であるチタニア、シリカ、ジルコニア及びこれらの複合酸化物、又はゼオライトに担持したものを用いることができる。 Here, in the exhaust gas treatment apparatus 10 according to the present embodiment, metal oxides such as V, W, Mo, Ni, Co, Fe, Cr, Mn, and Cu are used as the denitration catalyst used in the denitration catalyst layer 13 for reducing denitration. Or a sulfate, or a noble metal such as Pt, Ru, Rh, Pd, Ir, or a mixture thereof supported on titania, silica, zirconia and a composite oxide thereof, or zeolite can be used. .
　また、本実施例において、用いるＨＣｌについて、特に濃度の制限はないが、例えば濃塩酸から５％程度の希塩酸を用いることができる。また、本実施例において、使用する塩素化剤として塩化水素（ＨＣｌ）を用いて説明したが、本発明はこれに限定されるものではなく、塩素化剤としては、排ガス中のＨｇが脱硝触媒の存在下で反応してＨｇＣｌ及び／又はＨｇＣｌ2の塩化水銀を生成するものであればよい。例えば塩化アンモニウム、塩素、次亜塩素酸、次亜塩素酸アンモニウム、亜塩素酸、亜塩素酸アンモニウム、塩素酸、塩素酸アンモニウム、過塩素酸、過塩素酸アンモニウム、その他上記酸のアミン塩類、その他の塩類等が例示される。 In the present embodiment, the concentration of HCl to be used is not particularly limited. For example, dilute hydrochloric acid of about 5% from concentrated hydrochloric acid can be used. In this embodiment, hydrogen chloride (HCl) was used as the chlorinating agent to be used. However, the present invention is not limited to this, and Hg in the exhaust gas is a denitration catalyst. As long as it produces HgCl and / or HgCl 2 mercury chloride. For example, ammonium chloride, chlorine, hypochlorous acid, ammonium hypochlorite, chlorous acid, ammonium chlorite, chloric acid, ammonium chlorate, perchloric acid, ammonium perchlorate, and other amine salts of the above acids And the like.
　また、本実施例において、ボイラ１１から排出される排ガス１２にＨＣｌとＮＨ3の両方を添加しているが、煙道１９内における排ガス１２にＮＨ3を添加しなくてもよい。排ガス処理装置１０の脱硝触媒層１３では、排ガス１２中のＮＯｘ（窒素酸化物）を除去すると共に、排ガス１２中のＨｇを酸化し、後流側に設けられる脱硫装置（図示しない）でＨｇを除去するものであるため、煙道１９内で排ガス１２にＮＨ3を添加しなくても、脱硝触媒層１３の脱硝触媒の存在下でＨＣｌによりＨｇを塩化物に転換し、脱硫装置（図示しない）でＨｇを除去できる効果には変わりないからである。 In this embodiment, both HCl and NH 3 are added to the exhaust gas 12 discharged from the boiler 11, but NH 3 may not be added to the exhaust gas 12 in the flue 19. The denitration catalyst layer 13 of the exhaust gas treatment device 10 removes NOx (nitrogen oxides) in the exhaust gas 12 and oxidizes Hg in the exhaust gas 12, and Hg is removed by a desulfurization device (not shown) provided on the downstream side. Since it is to be removed, even if NH 3 is not added to the exhaust gas 12 in the flue 19, Hg is converted to chloride with HCl in the presence of the denitration catalyst in the denitration catalyst layer 13, and a desulfurization apparatus (not shown) This is because the effect of removing Hg does not change.
　また、アンモニアを添加する際、該アンモニアの添加量を低減することで水銀の酸化効率が向上するので、アンモニアを添加する場合においても最低量のアンモニアとすることが望ましい。 In addition, when adding ammonia, the oxidation efficiency of mercury is improved by reducing the amount of ammonia added. Therefore, it is desirable to use the minimum amount of ammonia even when ammonia is added.
　また、本実施例では、石炭や重油などの硫黄、水銀等を含む化石燃料を燃焼する火力発電所のボイラから排出される排ガスを用いて説明したが、本発明はこれに限定されるものではなく、ＮＯｘ濃度が低く、二酸化炭素、酸素、ＳＯｘ、煤塵、あるいは水分を含む排ガス、硫黄、水銀等を含む燃料を燃焼する工場などから排出されるボイラ排ガス、金属工場、石油精製工場、石油化学工場等から排出される加熱炉排ガス等にも適用できる。 In the present embodiment, the exhaust gas discharged from the boiler of the thermal power plant that burns fossil fuel containing sulfur, mercury, etc. such as coal and heavy oil is described, but the present invention is not limited to this. NOx concentration is low, boiler exhaust gas emitted from a factory that burns fuel containing carbon dioxide, oxygen, SOx, dust, or moisture, fuel containing sulfur, mercury, etc., metal factory, oil refinery factory, petrochemical It can also be applied to furnace exhaust gas discharged from factories and the like.
　このように、本実施例に係る排ガス処理装置を適用した排ガス処理システムによれば、実機の運転条件やそのバラツキ度合いをモニタリングして、それらに応じて、塩化水素の噴霧量を調整するので、所要の水銀性能を確保することができる。 Thus, according to the exhaust gas treatment system to which the exhaust gas treatment apparatus according to the present embodiment is applied, the operating conditions of the actual machine and the degree of variation thereof are monitored, and the spray amount of hydrogen chloride is adjusted accordingly, The required mercury performance can be ensured.
　以上のように、本発明に係る排ガス処理装置は、前記塩素化剤を供給する供給位置は、脱硝触媒部の前流側煙道の断面形状が軸方向に亙って均一な部分とするので、所要の水銀性能を確保することができるので、火力発電所等の水銀を含有する石炭や重油などの化石燃料を燃焼する装置から排出される排ガスの処理に用いるのに適している。 As described above, in the exhaust gas treatment apparatus according to the present invention, the supply position for supplying the chlorinating agent is a section where the cross-sectional shape of the upstream-side flue of the denitration catalyst part is uniform over the axial direction. Since the required mercury performance can be ensured, it is suitable for use in the treatment of exhaust gas discharged from an apparatus that burns fossil fuels such as coal and heavy oil containing mercury such as thermal power plants.
　１０　排ガス処理装置
　１３　脱硝触媒層
　３１　第１のモニタリング部
　３２　第２のモニタリング部
　４１　塩化水素供給領域 DESCRIPTION OF SYMBOLS 10 Exhaust gas treatment apparatus 13 Denitration catalyst layer 31 1st monitoring part 32 2nd monitoring part 41 Hydrogen chloride supply area

Claims (4)

  1. 　ボイラからの排ガス中の窒素酸化物を除去すると共に、排ガス中に塩素化剤を噴霧して水銀を酸化する脱硝触媒部を有する排ガス処理装置において、
    　前記塩素化剤を供給する供給位置は、脱硝触媒部の前流側煙道の断面形状が軸方向に亙って均一な部分とすることを特徴とする排ガス処理装置。     In an exhaust gas treatment apparatus having a denitration catalyst part that removes nitrogen oxides in exhaust gas from a boiler and oxidizes mercury by spraying a chlorinating agent in the exhaust gas,
    The exhaust gas treatment apparatus according to claim 1, wherein the supply position for supplying the chlorinating agent is a portion where the cross-sectional shape of the upstream-side flue of the denitration catalyst section is uniform in the axial direction.
  2. 　請求項１において、
    　前記断面形状が均一な部分は、脱硝触媒部の前流側煙道の鉛直部であることを特徴とする排ガス処理装置。     In claim 1,
    The exhaust gas treatment apparatus characterized in that the portion having a uniform cross-sectional shape is a vertical portion of a flue on the upstream side of the denitration catalyst portion.
  3. 　前記ボイラと、
    　前記ボイラの下流側の煙道に排出された排ガスに塩素化剤を注入する塩素化剤供給部と、
    　請求項１又は２の排ガス処理装置と、
    　脱硝後の排ガス中の硫黄酸化物を除去する脱硫装置と、
    　脱硫後のガスを外部に排出する煙突とを有することを特徴とする排ガス処理システム。     The boiler;
    A chlorinating agent supply unit for injecting a chlorinating agent into the exhaust gas discharged into the flue downstream of the boiler;
    An exhaust gas treatment device according to claim 1 or 2,
    A desulfurization device for removing sulfur oxides in exhaust gas after denitration,
    An exhaust gas treatment system comprising a chimney for discharging the desulfurized gas to the outside.
  4. 　請求項３において、
    　前記ボイラの下流側の煙道に排出された排ガスにアンモニアを投入するアンモニア供給部が設けられてなることを特徴とする排ガス処理システム。     In claim 3,
    An exhaust gas treatment system comprising an ammonia supply unit for introducing ammonia into the exhaust gas discharged to the flue downstream of the boiler.
PCT/JP2009/063819 2008-08-20 2009-08-04 Apparatus for treating discharge gas and system for treating discharge gas WO2010021237A1 (en)

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