WO2010016496A1 - Apparatus for treating discharge gas, system for treating discharge gas, and system for controlling ability to oxidize mercury in discharge gas - Google Patents

Apparatus for treating discharge gas, system for treating discharge gas, and system for controlling ability to oxidize mercury in discharge gas Download PDF

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Publication number
WO2010016496A1
WO2010016496A1 PCT/JP2009/063818 JP2009063818W WO2010016496A1 WO 2010016496 A1 WO2010016496 A1 WO 2010016496A1 JP 2009063818 W JP2009063818 W JP 2009063818W WO 2010016496 A1 WO2010016496 A1 WO 2010016496A1
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Prior art keywords
exhaust gas
mercury
denitration catalyst
chlorinating agent
monitoring unit
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PCT/JP2009/063818
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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
    • B01D53/75—Multi-step processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • 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
    • B01D2257/00—Components to be removed
    • B01D2257/30—Sulfur compounds
    • B01D2257/302—Sulfur oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/40—Nitrogen compounds
    • B01D2257/404—Nitrogen oxides other than dinitrogen oxide
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/12—Methods and means for introducing reactants

Definitions

  • the present invention relates to an exhaust gas treatment apparatus, an exhaust gas treatment system, and a mercury oxidation performance management system in exhaust gas for oxidizing mercury in exhaust gas discharged from a combustion apparatus.
  • 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 gas on an exhaust gas flue have been put to 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.
  • an exhaust gas flue 19 upstream 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 hydrogen chloride. It vaporizes in the spraying part 21 and is sprayed on the exhaust gas 12 as hydrogen chloride through a hydrogen chloride (HCl) spray nozzle 21a.
  • HCl hydrogen chloride
  • the flue 19 of the exhaust gas upstream of the denitration catalyst layer 13 is provided with an injection portion of ammonia (NH 3 ), and the ammonia supplied from the NH 3 supply unit 29 is supplied to the exhaust gas 12 by the ammonia spray nozzle 29a.
  • NH 3 ammonia
  • the ammonia supplied from the NH 3 supply unit 29 is supplied to the exhaust gas 12 by the ammonia spray nozzle 29a.
  • NOx nitrogen oxide
  • 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 29a is sprayed into the flue gas 12, in the denitration catalyst layer 13, the following As shown in the formula, NOx is replaced with nitrogen (N 2 ) by a reduction reaction, and denitration is performed.
  • NOx is replaced with 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 a liquid HCl supply unit 20 to a hydrogen chloride (HCl) spray unit 21 where hydrochloric acid is vaporized and hydrogen chloride ( HCl) is sprayed into the exhaust gas 12 by the hydrogen chloride spray nozzle 21a to oxidize (chlorinate) low-solubility Hg on the denitration catalyst 13 in the denitration catalyst layer 13 as shown in the following formula. It is converted into mercury (HgCl 2 ), and Hg contained in the exhaust gas 12 is removed by a desulfurization device 16 provided on the downstream side. Hg + 2HCl + 1 / 2O 2 ⁇ HgCl 2 + H 2 O (3)
  • the combustion gas 12 contains a Cl content, but the Cl content varies depending on the type of fuel, and the Cl concentration in the exhaust gas Since it is difficult to control the amount of HCl, it is preferable to add more HCl or the like than necessary to the upstream of the exhaust gas treatment system 100 to reliably remove Hg.
  • the denitration catalyst layer 13 uses a honeycomb shape having a rectangular passage 14 arranged in a lattice and carrying a denitration catalyst, and the cross-sectional shape of the passage is, for example, triangular or quadrangular
  • the passage is a polygonal shape.
  • the airflow of the exhaust gas 12 supplied to the conventional denitration catalyst layer 13 is rectified by a rectification means (not shown) in front of the denitration catalyst layer 13 and is in a laminar flow state.
  • the required amount of hydrogen chloride is different, and the amount of hydrogen chloride sprayed may be excessive or insufficient.
  • the oxidation performance of mercury in the exhaust gas is lowered. Therefore, it is eagerly desired that the required mercury oxidation performance can be achieved regardless of the conditions of exhaust gas flow and operating conditions.
  • the present invention provides an exhaust gas treatment apparatus, an exhaust gas treatment system, and a mercury oxidation performance management system in exhaust gas that can prevent mercury oxidation performance in exhaust gas from being deteriorated and always perform mercury treatment stably.
  • the task is to do.
  • the first invention of the present invention for solving the above-mentioned problems 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.
  • An exhaust gas treatment apparatus comprising: a first monitoring unit that measures at least one of exhaust gas temperature, exhaust gas flow velocity distribution, and chlorinating agent concentration distribution on an inlet side of the denitration catalyst unit; and an outlet of the denitration catalyst unit Side, a second monitoring unit that measures the amount of mercury in the exhaust gas, and a chlorinating agent spray amount adjusting unit that adjusts the spray amount of the chlorinating agent according to the results of the first monitoring unit and the second monitoring unit;
  • An exhaust gas treatment apparatus comprising:
  • the chlorinating agent spray amount adjusting device is performed by adjusting a spray amount from a spray nozzle.
  • a third invention is characterized in that, in the first or second invention, a cooling device is provided in the denitration catalyst section, and when the temperature is higher than a predetermined set temperature, the temperature is lowered and the mercury oxidation rate is improved. Located in the exhaust gas treatment device.
  • the boiler a chlorinating agent supply unit that injects a chlorinating agent into the exhaust gas discharged to the exhaust gas flue downstream of the boiler, and any one of the first to third exhaust gas treatment apparatuses.
  • a desulfurization device that removes sulfur oxides in the exhaust gas after denitration, and a chimney that discharges the gas after desulfurization to the outside.
  • an exhaust gas treatment system according to the fourth aspect of the invention, further comprising an ammonia supply unit for introducing ammonia into the exhaust gas discharged to the exhaust gas flue downstream of the boiler.
  • the sixth invention removes nitrogen oxides in exhaust gas from the boiler, and sprays a chlorinating agent into the exhaust gas to oxidize mercury in the denitration catalyst unit.
  • a chlorinating agent into the exhaust gas to oxidize mercury in the denitration catalyst unit.
  • At the inlet side at least one of the exhaust gas temperature, the exhaust gas flow velocity distribution, and the chlorinating agent concentration distribution is measured by the first monitoring unit, and the mercury amount in the exhaust gas is measured at the outlet side of the denitration catalyst unit.
  • the mercury oxidation performance is managed by adjusting the spray amount of the chlorinating agent by the chlorinating agent spray amount adjusting unit according to the results of the first monitoring unit and the second monitoring unit. It is in the mercury oxidation performance management system in the exhaust gas.
  • a cooling device is provided in the denitration catalyst section, and when the temperature is higher than a predetermined set temperature, the temperature is lowered and the mercury oxidation rate is improved.
  • the mercury oxidation performance management system is provided in the denitration catalyst section, and when the temperature is higher than a predetermined set temperature, the temperature is lowered and the mercury oxidation rate is improved.
  • the required mercury 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 exhaust gas temperature and the mercury oxidation rate.
  • FIG. 4 is a relationship diagram between the amount of hydrogen chloride and the mercury oxidation rate.
  • FIG. 5 is a schematic diagram of an exhaust gas treatment system for a coal fired boiler.
  • FIG. 1 is a schematic view showing an exhaust gas treatment apparatus according to an embodiment
  • FIG. 2 is a perspective view showing a part of the configuration of a denitration catalyst section 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 oxide (NOx) in the exhaust gas 12 from the boiler 11, and chlorinates as a chlorinating agent in the exhaust gas 12.
  • An exhaust gas treatment apparatus having a denitration catalyst layer 13 for spraying hydrogen to oxidize mercury (Hg), and at the inlet side of the denitration catalyst layer 13, at least an exhaust gas temperature, an exhaust gas flow velocity distribution, and a hydrogen chloride concentration distribution.
  • the first monitoring unit 31 that measures one or more
  • the second monitoring unit 32 that measures the amount of mercury in the exhaust gas
  • the first monitoring unit 31 and the second monitoring on the outlet side of the denitration catalyst layer 13 A hydrogen chloride spray amount adjusting unit 33 that adjusts the spray amount of hydrogen chloride according to the result of the unit 32 is provided.
  • the operating condition exhaust gas temperature, exhaust gas flow velocity distribution, hydrogen chloride concentration distribution in the exhaust gas
  • the degree of variation of the exhaust gas treatment apparatus 10 are monitored by the first monitoring unit 31, and these values are calculated centrally.
  • the required mercury oxidation performance can be ensured by calculating with a device (CPU) and adjusting the amount of hydrogen chloride and the exhaust gas temperature accordingly.
  • the first monitoring unit 31 is provided with a plurality of sensors 31a to 31d on the inlet side of the denitration catalyst layer 13 in a direction orthogonal to the gas flow of the exhaust gas 12, and measures the operating conditions. You may make it increase / decrease suitably.
  • the second monitoring unit 32 is provided with a plurality of sensors 32a to 32b in the direction orthogonal to the gas flow on the outlet side of the denitration catalyst layer 13, and measures the operating conditions. May be increased or decreased as appropriate.
  • the denitration catalyst layer 13 is composed of three catalyst layers 13-1 to 13-3, but the present invention is not limited to this.
  • FIG. 3 is a graph showing the relationship between the exhaust gas temperature and the mercury oxidation rate, and it was confirmed that the mercury oxidation rate decreased as the temperature increased.
  • FIG. 4 is a relationship diagram between the amount of hydrogen chloride and the mercury oxidation rate, and it was confirmed that the mercury oxidation rate improved as the amount of hydrogen chloride increased.
  • the mercury oxidation performance can be significantly improved by considering the exhaust gas temperature.
  • the exhaust gas is set at a predetermined temperature (X), set to a predetermined hydrogen chloride amount (Y) when 20 degrees lower and 20 degrees higher than the predetermined temperature, and 100 ppm lower than the predetermined concentration
  • X a predetermined temperature
  • Y a predetermined hydrogen chloride amount
  • 100 ppm lower than the predetermined concentration The relationship between the variation in hydrogen chloride concentration variation (0, 10, 20%) and the flow velocity variation (0, 10, 20%) in the case of 100 ppm higher is shown.
  • an appropriate hydrogen chloride spray amount can be determined in consideration of variations in hydrogen chloride concentration and variations in flow velocity.
  • the variation was determined by (standard deviation of density) / (average value of cross-sectional density), (standard deviation of speed) / (average value of density of speed).
  • the predetermined temperature (X) may be 300 to 400 ° C.
  • the predetermined hydrogen chloride amount (Y) may be 200 to 1000 ppm.
  • the denitration catalyst layer 13 is cooled 34 a by the cooling device 34.
  • the temperature when the temperature is higher than the predetermined set temperature, the temperature can be lowered and the mercury oxidation rate can be improved.
  • the hydrogen chloride spray amount adjusting unit 33 is performed by adjusting the spray amount from the spray nozzle.
  • the mercury oxidation performance is managed by adjusting the hydrogen chloride spray amount by the hydrogen chloride spray amount adjusting unit 33 according to the results of the first monitoring unit 31 and the second monitoring unit 32.
  • As a system for managing mercury oxidation performance in exhaust gas it is possible to ensure stable and high mercury oxidation performance (for example, 95% or higher) even when operating conditions fluctuate when treating exhaust gas from boilers. Will be able to do.
  • 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.
  • the addition position of the HCl into the flue gas 12 in the exhaust gas flue 19, while the upstream side of the feed point of the NH 3, may be downstream of the feed point of the NH 3.
  • 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 exhaust gas 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 in a desulfurization device (not shown) provided on the downstream side. Therefore, without adding NH 3 to the exhaust gas 12 in the exhaust gas flue 19, Hg is converted to chloride with HCl in the presence of the denitration catalyst in the denitration catalyst layer 13, and a desulfurizer ( This is because the effect of removing Hg remains unchanged.
  • 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 exhaust gas treatment apparatus monitors the operating conditions and the degree of variation thereof, and adjusts the spray amount of hydrogen chloride according to them, so that the required mercury performance can be ensured. Therefore, it is suitable for use in the treatment of exhaust gas discharged from a fossil fuel such as coal or heavy oil containing mercury such as a thermal power plant.

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).  The apparatus is equipped with: a first monitoring unit (31) which determines at least one of the temperature of the discharge gas, flow rate distribution of the discharge gas, and hydrogen-chloride concentration distribution on the inlet side of the denitration catalyst layer (13); a second monitoring unit (32) which measures the amount of mercury contained in the discharge gas, on the outlet side of the denitration catalyst layer (13); and a hydrogen-chloride spray rate control unit (33) which regulates the amount of hydrogen chloride to be sprayed, based on the results sent from the first monitoring unit (31) and the second monitoring unit (32).

Description

排ガス処理装置、排ガス処理システム及び排ガス中の水銀酸化性能管理システムExhaust gas treatment device, exhaust gas treatment system, and mercury oxidation performance management system in exhaust gas
　本発明は、燃焼装置から排出される排ガス中の水銀の酸化処理を行う排ガス処理装置、排ガス処理システム及び排ガス中の水銀酸化性能管理システムに関する。 The present invention relates to an exhaust gas treatment apparatus, an exhaust gas treatment system, and a mercury oxidation performance management system in exhaust gas for oxidizing mercury in exhaust gas discharged from a combustion apparatus.
　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、排ガス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 gas on an exhaust gas flue have been put to practical use by NH 3 spraying of a denitration catalyst layer and gas spraying of a chlorinating agent.
　石炭焚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の前流の排ガス煙道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２１ａを介して塩化水素として排ガス１２に噴霧されている。 Further, an exhaust gas flue 19 upstream 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 hydrogen chloride. It vaporizes in the spraying part 21 and is sprayed on the exhaust gas 12 as hydrogen chloride through a hydrogen chloride (HCl) spray nozzle 21a.
　また、脱硝触媒層１３の前流の排ガスの煙道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２９ａ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。 The flue 19 of the exhaust gas upstream of the denitration catalyst layer 13 is provided with an injection portion of ammonia (NH 3 ), and the ammonia supplied from the NH 3 supply unit 29 is supplied to the exhaust gas 12 by the ammonia spray nozzle 29a. In order to reduce nitrogen oxide (NOx).
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２９ａ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 29a is sprayed into the flue gas 12, in the denitration catalyst layer 13, the following As shown in the formula, NOx is replaced with 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液体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） Hydrogen chloride is used for mercury oxidation, and hydrogen chloride used as a chlorinating agent is supplied from a liquid HCl supply unit 20 to a hydrogen chloride (HCl) spray unit 21 where hydrochloric acid is vaporized and hydrogen chloride ( HCl) is sprayed into the exhaust gas 12 by the hydrogen chloride spray nozzle 21a to oxidize (chlorinate) low-solubility Hg on the denitration catalyst 13 in the denitration catalyst layer 13 as shown in the following formula. It is converted into mercury (HgCl 2 ), and Hg contained in the exhaust gas 12 is removed by a 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、排ガス処理システム１００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, since the fuel contains Cl, the combustion gas 12 contains a Cl content, but the Cl content varies depending on the type of fuel, and the Cl concentration in the exhaust gas Since it is difficult to control the amount of HCl, it is preferable to add more HCl or the like than necessary to the upstream of the exhaust gas treatment system 100 to reliably remove Hg.
　また、脱硝触媒層１３は、格子状に配列して四角形状の通路１４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。 In addition, the denitration catalyst layer 13 uses a honeycomb shape having a rectangular passage 14 arranged in a lattice and carrying a denitration catalyst, and the cross-sectional shape of the passage is, for example, triangular or quadrangular The passage is a polygonal shape.
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、従来の脱硝触媒層１３に供給される排ガス１２の気流は、脱硝触媒層１３の手前で整流化手段（図示せず）により整流化され、層流状態であるが、実際の運転条件により、必要な塩化水素量が異なり、塩化水素の噴霧量に過不足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や運転条件によらず、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 airflow of the exhaust gas 12 supplied to the conventional denitration catalyst layer 13 is rectified by a rectification means (not shown) in front of the denitration catalyst layer 13 and is in a laminar flow state. The required amount of hydrogen chloride is different, and the amount of hydrogen chloride sprayed may be excessive or insufficient.
As a result, there is a problem that the oxidation performance of mercury in the exhaust gas is lowered.
Therefore, it is eagerly desired that the required mercury oxidation performance can be achieved regardless of the conditions of exhaust gas flow and operating conditions.
　本発明は、前記問題に鑑み、排ガス中の水銀の酸化性能の低下を防ぎ、常に安定して水銀処理を行うことができる排ガス処理装置、排ガス処理システム及び排ガス中の水銀酸化性能管理システムを提供することを課題とする。 In view of the above problems, the present invention provides an exhaust gas treatment apparatus, an exhaust gas treatment system, and a mercury oxidation performance management system in exhaust gas that can prevent mercury oxidation performance in exhaust gas from being deteriorated and always perform mercury treatment stably. The task is to do.
　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であって、前記脱硝触媒部の入口側において、排ガスの温度、排ガスの流速分布、塩素化剤濃度分布の少なくとも一以上を計測する第１のモニタリング部と、前記脱硝触媒部の出口側において、排ガス中の水銀量を計測する第２のモニタリング部と、第１のモニタリング部と第２のモニタリング部との結果により塩素化剤の噴霧量を調整する塩素化剤噴霧量調整部とを具備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-mentioned problems 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. An exhaust gas treatment apparatus, comprising: a first monitoring unit that measures at least one of exhaust gas temperature, exhaust gas flow velocity distribution, and chlorinating agent concentration distribution on an inlet side of the denitration catalyst unit; and an outlet of the denitration catalyst unit Side, a second monitoring unit that measures the amount of mercury in the exhaust gas, and a chlorinating agent spray amount adjusting unit that adjusts the spray amount of the chlorinating agent according to the results of the first monitoring unit and the second monitoring unit; An exhaust gas treatment apparatus comprising:
　第２の発明は、第１の発明において、前記塩素化剤噴霧量調整装置は、噴霧ノズルからの噴霧量の調整により行う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, in the first aspect of the invention, the chlorinating agent spray amount adjusting device is performed by adjusting a spray amount from a spray nozzle.
　第３の発明は、第１又は２の発明において、前記脱硝触媒部に冷却装置を設け、所定設定温度よりも高い場合には、温度を低下させ、水銀酸化率を向上させることを特徴とする排ガス処理装置にある。 A third invention is characterized in that, in the first or second invention, a cooling device is provided in the denitration catalyst section, and when the temperature is higher than a predetermined set temperature, the temperature is lowered and the mercury oxidation rate is improved. Located in the exhaust gas treatment device.
　第４の発明は、前記ボイラと、前記ボイラの下流側の排ガス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乃至３のいずれか一つ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 fourth aspect of the present invention, there is provided the boiler, a chlorinating agent supply unit that injects a chlorinating agent into the exhaust gas discharged to the exhaust gas flue downstream of the boiler, and any one of the first to third exhaust gas treatment apparatuses. And a desulfurization device that removes sulfur oxides in the exhaust gas after denitration, and a chimney that discharges the gas after desulfurization to the outside.
　第５の発明は、第４の発明において、前記ボイラの下流側の排ガス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 fifth aspect of the present invention, there is provided an exhaust gas treatment system according to the fourth aspect of the invention, further comprising an ammonia supply unit for introducing ammonia into the exhaust gas discharged to the exhaust gas flue downstream of the boiler.
　第６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脱硝触媒部で酸化する水銀酸化を行う際に、前記脱硝触媒部の入口側において、排ガスの温度、排ガスの流速分布、塩素化剤濃度分布の少なくとも一以上を第１のモニタリング部で計測すると共に、前記脱硝触媒部の出口側において、排ガス中の水銀量を第２のモニタリング部で計測し、第１のモニタリング部と第２のモニタリング部との結果により塩素化剤の噴霧量を塩素化剤噴霧量調整部により調整して、水銀酸化性能を管理することを特徴とする排ガス中の水銀酸化性能管理システムにある。 The sixth invention removes nitrogen oxides in exhaust gas from the boiler, and sprays a chlorinating agent into the exhaust gas to oxidize mercury in the denitration catalyst unit. At the inlet side, at least one of the exhaust gas temperature, the exhaust gas flow velocity distribution, and the chlorinating agent concentration distribution is measured by the first monitoring unit, and the mercury amount in the exhaust gas is measured at the outlet side of the denitration catalyst unit. The mercury oxidation performance is managed by adjusting the spray amount of the chlorinating agent by the chlorinating agent spray amount adjusting unit according to the results of the first monitoring unit and the second monitoring unit. It is in the mercury oxidation performance management system in the exhaust gas.
　第７の発明は、第６の発明において、前記脱硝触媒部に冷却装置を設け、所定設定温度よりも高い場合には、温度を低下させ、水銀酸化率を向上させることを特徴とする排ガス中の水銀酸化性能管理システムにある。 According to a seventh aspect of the present invention, in the exhaust gas according to the sixth aspect of the present invention, a cooling device is provided in the denitration catalyst section, and when the temperature is higher than a predetermined set temperature, the temperature is lowered and the mercury oxidation rate is improved. The mercury oxidation performance management system.
　本発明によれば、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、塩素化剤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。 According to the present invention, since the operating conditions of the actual machine and the degree of variation are monitored and the spray amount of the chlorinating agent is adjusted according to them, the required mercury 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、排ガス温度と水銀酸化率との関係図である。FIG. 3 is a relationship diagram between the exhaust gas temperature and the mercury oxidation rate. 図４は、塩化水素量と水銀酸化率との関係図である。FIG. 4 is a relationship diagram between the amount of hydrogen chloride and the mercury oxidation rate. 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、実施例に係る脱硝触媒部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であって、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と、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塩化水素噴霧量調整部３３とを具備するものである。 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 view showing an exhaust gas treatment apparatus according to an embodiment, and FIG. 2 is a perspective view showing a part of the configuration of a denitration catalyst section 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 oxide (NOx) in the exhaust gas 12 from the boiler 11, and chlorinates as a chlorinating agent in the exhaust gas 12. An exhaust gas treatment apparatus having a denitration catalyst layer 13 for spraying hydrogen to oxidize mercury (Hg), and at the inlet side of the denitration catalyst layer 13, at least an exhaust gas temperature, an exhaust gas flow velocity distribution, and a hydrogen chloride concentration distribution. The first monitoring unit 31 that measures one or more, the second monitoring unit 32 that measures the amount of mercury in the exhaust gas, and the first monitoring unit 31 and the second monitoring on the outlet side of the denitration catalyst layer 13 A hydrogen chloride spray amount adjusting unit 33 that adjusts the spray amount of hydrogen chloride according to the result of the unit 32 is provided.
　本発明では、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ことができる。 In the present invention, the operating condition (exhaust gas temperature, exhaust gas flow velocity distribution, hydrogen chloride concentration distribution in the exhaust gas) and the degree of variation of the exhaust gas treatment apparatus 10 are monitored by the first monitoring unit 31, and these values are calculated centrally. The required mercury oxidation performance can be ensured by calculating with a device (CPU) and adjusting the amount of hydrogen chloride and the exhaust gas temperature accordingly.
　第１のモニタリング部３１は、脱硝触媒層１３の入口側において、排ガス１２のガス流れに直交する方向に複数のセンサ３１ａ～３１ｄを設けて、運転条件を計測するようにしているが、そのセンサの数は適宜増減するようにしてもよい。
　また第２のモニタリング部３２は、脱硝触媒層１３の出口側において、ガス流れに直交する方向に複数のセンサ３２ａ～３２ｂを設けて、運転条件を計測するようにしているが、そのセンサの数は適宜増減するようにしてもよい。
　なお、図２においては、脱硝触媒層１３は３つの触媒層１３－１～１３－３から構成されているが、本発明はこれに限定されるものではない。 The first monitoring unit 31 is provided with a plurality of sensors 31a to 31d on the inlet side of the denitration catalyst layer 13 in a direction orthogonal to the gas flow of the exhaust gas 12, and measures the operating conditions. You may make it increase / decrease suitably.
The second monitoring unit 32 is provided with a plurality of sensors 32a to 32b in the direction orthogonal to the gas flow on the outlet side of the denitration catalyst layer 13, and measures the operating conditions. May be increased or decreased as appropriate.
In FIG. 2, the denitration catalyst layer 13 is composed of three catalyst layers 13-1 to 13-3, but the present invention is not limited to this.
　図３は排ガス温度と水銀酸化率との関係図であり、温度が高くなるほど水銀酸化率が低下するのが確認された。 FIG. 3 is a graph showing the relationship between the exhaust gas temperature and the mercury oxidation rate, and it was confirmed that the mercury oxidation rate decreased as the temperature increased.
　図４は塩化水素量と水銀酸化率との関係図であり、塩化水素量が多くなるほど水銀酸化率が向上するのが確認された。
　なお、図３に示す排ガス温度と、図４に示す塩化水素の量とにおいては、排ガス温度を考慮するほうが、水銀酸化性能を大幅に向上できることが確認された。 FIG. 4 is a relationship diagram between the amount of hydrogen chloride and the mercury oxidation rate, and it was confirmed that the mercury oxidation rate improved as the amount of hydrogen chloride increased.
In addition, in the exhaust gas temperature shown in FIG. 3 and the amount of hydrogen chloride shown in FIG. 4, it was confirmed that the mercury oxidation performance can be significantly improved by considering the exhaust gas temperature.
　下記、表１に排ガスを所定温度（Ｘ）に設定し、その所定温度から２０度低い場合と２０度高い場合における、所定塩化水素量（Ｙ）に設定し、その所定濃度から１００ｐｐｍ低い場合と、１００ｐｐｍ高い場合とにおける、塩化水素濃度のバラツキ（０，１０，２０％）の変化と流速バラツキ（０，１０，２０％）の関係を示す。 In Table 1 below, the exhaust gas is set at a predetermined temperature (X), set to a predetermined hydrogen chloride amount (Y) when 20 degrees lower and 20 degrees higher than the predetermined temperature, and 100 ppm lower than the predetermined concentration The relationship between the variation in hydrogen chloride concentration variation (0, 10, 20%) and the flow velocity variation (0, 10, 20%) in the case of 100 ppm higher is shown.
Figure JPOXMLDOC01-appb-T000001
 　これらにより、塩化水素濃度のバラツキと流速のバラツキを考慮して適正な塩化水素の噴霧量を決定することができる。
　なお、バラツキは（濃度の標準偏差）／（断面の濃度の平均値）、（速度の標準偏差）／（速度の濃度の平均値）により求めた。
Figure JPOXMLDOC01-appb-T000001
 Thus, an appropriate hydrogen chloride spray amount can be determined in consideration of variations in hydrogen chloride concentration and variations in flow velocity.
The variation was determined by (standard deviation of density) / (average value of cross-sectional density), (standard deviation of speed) / (average value of density of speed).
　ここで、運転条件により、適宜設定すればよいが、所定温度（Ｘ）としては、３００～４００℃とすればよく、所定塩化水素量（Ｙ）としては、２００～１０００ｐｐｍとすればよい。 Here, it may be set as appropriate depending on the operating conditions, but the predetermined temperature (X) may be 300 to 400 ° C., and the predetermined hydrogen chloride amount (Y) may be 200 to 1000 ppm.
　また、第１のモニタリング部３１の計測結果により、温度が高い場合には、冷却装置３４により脱硝触媒層１３を冷却３４ａするようにしている。これにより所定設定温度よりも高い場合には、温度を低下させ、水銀酸化率を向上させることができることとなる。 Further, according to the measurement result of the first monitoring unit 31, when the temperature is high, the denitration catalyst layer 13 is cooled 34 a by the cooling device 34. As a result, when the temperature is higher than the predetermined set temperature, the temperature can be lowered and the mercury oxidation rate can be improved.
　ここで、前記塩化水素噴霧量調整部３３は、噴霧ノズルからの噴霧量の調整により行うこととするのが好ましい。 Here, it is preferable that the hydrogen chloride spray amount adjusting unit 33 is performed by adjusting the spray amount from the spray nozzle.
　このように、本発明によれば、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塩化水素噴霧量調整部３３により調整して、水銀酸化性能を管理する排ガス中の水銀酸化性能管理システムを構築することができるので、ボイラからの排ガスを処理する際に、運転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。 As described above, according to the present invention, the mercury oxidation performance is managed by adjusting the hydrogen chloride spray amount by the hydrogen chloride spray amount adjusting unit 33 according to the results of the first monitoring unit 31 and the second monitoring unit 32. As a system for managing mercury oxidation performance in exhaust gas, it is possible to ensure stable and high mercury oxidation performance (for example, 95% or higher) even when operating conditions fluctuate when treating exhaust gas from boilers. Will be able to do.
　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、排ガス煙道１９内における排ガス１２へのＨＣｌの添加位置は、ＮＨ3の添加位置よりも上流側としているが、ＮＨ3の添加位置よりも下流側としてもよい。 The addition position of the HCl into the flue gas 12 in the exhaust gas flue 19, while the upstream side of the feed point of the NH 3, may be downstream of the feed point of the NH 3.
　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、排ガス煙道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（図示せず）でＨｇを除去するものであるため、排ガス煙道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（図示せず）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 exhaust gas 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 in a desulfurization device (not shown) provided on the downstream side. Therefore, without adding NH 3 to the exhaust gas 12 in the exhaust gas flue 19, Hg is converted to chloride with HCl in the presence of the denitration catalyst in the denitration catalyst layer 13, and a desulfurizer ( This is because the effect of removing Hg remains unchanged.
　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、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, the exhaust gas treatment apparatus according to the present invention monitors the operating conditions and the degree of variation thereof, and adjusts the spray amount of hydrogen chloride according to them, so that the required mercury performance can be ensured. Therefore, it is suitable for use in the treatment of exhaust gas discharged from a fossil fuel such as coal or heavy oil containing mercury such as a thermal power plant.
　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
　３３　塩化水素噴霧量調整部
　３４　冷却装置 DESCRIPTION OF SYMBOLS 10 Exhaust gas treatment apparatus 13 Denitration catalyst layer 31 1st monitoring part 32 2nd monitoring part 33 Hydrogen chloride spray amount adjustment part 34 Cooling device

Claims (7)

  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であって、
    　前記脱硝触媒部の入口側において、排ガスの温度、排ガスの流速分布、塩素化剤濃度分布の少なくとも一以上を計測する第１のモニタリング部と、
    　前記脱硝触媒部の出口側において、排ガス中の水銀量を計測する第２のモニタリング部と、
    　第１のモニタリング部と第２のモニタリング部との結果により塩素化剤の噴霧量を調整する塩素化剤噴霧量調整部とを具備することを特徴とする排ガス処理装置。     An exhaust gas treatment apparatus having a denitration catalyst unit that removes nitrogen oxides in exhaust gas from a boiler and oxidizes mercury by spraying a chlorinating agent in the exhaust gas,
    A first monitoring unit that measures at least one of exhaust gas temperature, exhaust gas flow velocity distribution, and chlorinating agent concentration distribution on the inlet side of the denitration catalyst unit;
    A second monitoring unit for measuring the amount of mercury in the exhaust gas at the outlet side of the denitration catalyst unit;
    An exhaust gas treatment apparatus comprising: a chlorinating agent spray amount adjusting unit that adjusts a spray amount of the chlorinating agent according to a result of the first monitoring unit and the second monitoring unit.
  2. 　請求項１において、
    　前記塩素化剤噴霧量調整部は、噴霧ノズルからの噴霧量の調整により行うことを特徴とする排ガス処理装置。     In claim 1,
    The exhaust gas treatment apparatus, wherein the chlorinating agent spray amount adjusting unit is performed by adjusting a spray amount from a spray nozzle.
  3. 　請求項１又は２において、
    　前記脱硝触媒部に冷却装置を設け、
    　所定設定温度よりも高い場合には、温度を低下させ、水銀酸化率を向上させることを特徴とする排ガス処理装置。     In claim 1 or 2,
    A cooling device is provided in the denitration catalyst part,
    An exhaust gas treatment apparatus characterized by lowering the temperature and improving the mercury oxidation rate when the temperature is higher than a predetermined set temperature.
  4. 　前記ボイラと、
    　前記ボイラの下流側の排ガス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乃至３のいずれか一つ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 to the exhaust gas flue downstream of the boiler;
    An exhaust gas treatment apparatus according to any one of claims 1 to 3,
    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.
  5. 　請求項４において、
    　前記ボイラの下流側の排ガス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 4,
    An exhaust gas treatment system comprising an ammonia supply unit for introducing ammonia into the exhaust gas discharged to the exhaust gas flue downstream of the boiler.
  6. 　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脱硝触媒部で酸化する水銀酸化を行う際に、
    　前記脱硝触媒部の入口側において、排ガスの温度、排ガスの流速分布、塩素化剤濃度分布の少なくとも一以上を第１のモニタリング部で計測すると共に、
    　前記脱硝触媒部の出口側において、排ガス中の水銀量を第２のモニタリング部で計測し、
    　第１のモニタリング部と第２のモニタリング部との結果により塩素化剤の噴霧量を塩素化剤噴霧量調整部により調整して、水銀酸化性能を管理することを特徴とする排ガス中の水銀酸化性能管理システム。     While removing nitrogen oxides in exhaust gas from the boiler and spraying a chlorinating agent in the exhaust gas to oxidize mercury in the denitration catalyst part, mercury oxidation is performed.
    On the inlet side of the denitration catalyst unit, the first monitoring unit measures at least one of the temperature of the exhaust gas, the flow rate distribution of the exhaust gas, and the chlorinating agent concentration distribution,
    On the outlet side of the denitration catalyst unit, the amount of mercury in the exhaust gas is measured by the second monitoring unit,
    Mercury oxidation in exhaust gas characterized in that mercury oxidation performance is controlled by adjusting chlorinating agent spray amount by chlorinating agent spray amount adjusting unit according to results of first monitoring unit and second monitoring unit Performance management system.
  7. 　請求項６において、
    　前記脱硝触媒部に冷却装置を設け、
    　所定設定温度よりも高い場合には、温度を低下させ、水銀酸化率を向上させることを特徴とする排ガス中の水銀酸化性能管理システム。     In claim 6,
    A cooling device is provided in the denitration catalyst part,
    A mercury oxidation performance management system in exhaust gas, characterized in that when the temperature is higher than a predetermined set temperature, the temperature is lowered and the mercury oxidation rate is improved.
PCT/JP2009/063818 2008-08-07 2009-08-04 Apparatus for treating discharge gas, system for treating discharge gas, and system for controlling ability to oxidize mercury in discharge gas WO2010016496A1 (en)

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