WO2011142376A1 - Emission gas processing system with carbon dioxide chemical absorption device - Google Patents

Emission gas processing system with carbon dioxide chemical absorption device Download PDF

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Publication number
WO2011142376A1
WO2011142376A1 PCT/JP2011/060818 JP2011060818W WO2011142376A1 WO 2011142376 A1 WO2011142376 A1 WO 2011142376A1 JP 2011060818 W JP2011060818 W JP 2011060818W WO 2011142376 A1 WO2011142376 A1 WO 2011142376A1
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Prior art keywords
exhaust gas
heat
chemical absorption
heat exchanger
emission gas
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PCT/JP2011/060818
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French (fr)
Japanese (ja)
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宣明 清水
森本　信夫
尾田　直己
田口　善規
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バブコック日立株式会社
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    • 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
    • F23J15/006—Layout of treatment plant
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
    • F23G7/06—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases
    • F23G7/07—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases in which combustion takes place in the presence of catalytic material
    • 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
    • F23J15/022—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material for removing solid particulate material from the gasflow
    • F23J15/025—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material for removing solid particulate material from the gasflow using filters
    • 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
    • F23J15/04—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material using washing fluids
    • 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
    • F23J15/08—Arrangements of devices for treating smoke or fumes of heaters
    • 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
    • B01D2257/50—Carbon oxides
    • B01D2257/504—Carbon dioxide
    • 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
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases
    • 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
    • B01D53/48—Sulfur compounds
    • B01D53/50—Sulfur oxides
    • B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
    • 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
    • B01D53/62—Carbon oxides
    • 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
    • B01D53/8665—Removing heavy metals or compounds thereof, e.g. mercury
    • 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
    • F23J2215/50—Carbon dioxide
    • 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
    • F23J2219/40—Sorption with wet devices, e.g. scrubbers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L2900/00—Special arrangements for supplying or treating air or oxidant for combustion; Injecting inert gas, water or steam into the combustion chamber
    • F23L2900/15043—Preheating combustion air by heat recovery means located in the chimney, e.g. for home heating devices
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00—Capture or disposal of greenhouse gases
    • Y02C20/40—Capture or disposal of greenhouse gases of CO2
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/32—Direct CO2 mitigation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

Definitions

  • the present invention relates to an exhaust gas treatment system having a carbon dioxide CO 2 chemical absorption facility, and more particularly to an exhaust gas treatment system including a wet flue gas desulfurization device, a CO 2 chemical absorption facility, and a catalyst device for removing mercury in the exhaust gas.
  • exhaust gases discharged from coal-fired boilers and the like contain heavy metals such as nitrogen oxides, sulfur oxides, dust, and mercury. After installing and removing the harmful substances in the exhaust gas, it is released into the atmosphere as clean gas. In addition, regarding the recent global warming problem, it has become necessary to separate and recover carbon dioxide (CO 2 ) from exhaust gas.
  • CO 2 carbon dioxide
  • FIG. 4 shows an example of a conventional smoke treatment system and a CO 2 recovery system.
  • the combustion exhaust gas discharged from the boiler 1 removes nitrogen oxides and mercury by the denitration device 2, passes through the air preheater 3, removes the dust in the exhaust gas by the dust collector 5, and further increases the pressure by the induction fan 6.
  • the sulfur oxide is removed by the wet flue gas desulfurization apparatus 7. Nitrogen oxides, the exhaust gas after the mercury and sulfur dioxide has been removed, is sent to the CO 2 chemical absorption equipment 11, the chemical absorption of CO 2, separated from the exhaust gas of CO 2, the recovery is performed.
  • Mercury (Hg) in the exhaust gas reacts with chlorine (Cl) in the exhaust gas by the oxidation reaction of the denitration catalyst that constitutes the denitration device 2 and is converted to the form of mercury oxide (HgCl 2 ).
  • a catalyst having a catalyst composition with a low SO 2 oxidation capability is used as a denitration catalyst so as not to increase SO 3 due to oxidation of sulfur dioxide (SO 2 ) In some cases.
  • Mercury converted into the form of mercury oxide HgCl 2 having high water solubility due to the oxidation ability of the catalyst is mainly absorbed and removed from the exhaust gas by the limestone slurry absorbent of the wet flue gas desulfurization apparatus 7.
  • FIG. 5 shows an example of a CO 2 chemical absorption facility using such an amine absorbing solution.
  • the exhaust gas 20 is introduced into the absorption tower 25, and after CO 2 is removed by contact with the amine absorbing solution, it is discharged to the outside as de-CO 2 gas 27.
  • the amine absorption liquid that has absorbed CO 2 is introduced into the regeneration tower 26 by the absorption liquid circulation pump 28, where it is heated by steam, and the amine and CO 2 are separated and recovered as high-purity CO 2 gas 29.
  • the heating steam in the regeneration tower 26 is obtained by heating the amine absorbing liquid with the steam 32 using the reboiler 30.
  • divalent mercury (Hg 2+ ) out of mercury in the exhaust gas is removed from the exhaust gas by being absorbed by the limestone slurry absorbent in the wet desulfurization apparatus 7.
  • divalent mercury (Hg 2+ ) absorbed in the limestone slurry is not always stable and is reduced to metallic mercury (HgO) due to changes in operating conditions such as pH of the absorbing solution. There was a problem of being released again.
  • Gypsum produced by wet desulfurization equipment is effectively used as a raw material for gypsum board and cement, but its effective use becomes difficult due to the inclusion of mercury, and even if it is disposed of, the mercury in the gypsum vaporizes again. There is a problem of being released into the atmosphere.
  • An object of the present invention is to provide an exhaust gas treatment system equipped with a wet flue gas desulfurization facility and a CO 2 chemical absorption facility that solves the above-mentioned problems caused by mercury in the exhaust gas and prevents the release of metallic mercury to the outside. Is to provide.
  • An air preheater that heats combustion air in a fossil fuel combustion furnace, a dust collector that is installed downstream of the air preheater and collects dust in the exhaust gas, and sulfur oxidation in the exhaust gas
  • An exhaust gas treatment system equipped with a wet desulfurization apparatus for wet processing of substances and a CO 2 chemical absorption facility for absorbing and separating CO 2 from the exhaust gas, wherein the heat for exhaust gas heat recovery is provided between the air preheater and the dust collector.
  • An exhaust gas reheating heat exchanger that raises the exhaust gas temperature by heat recovered by the heat recovery heat exchanger is provided between the exchanger, the wet desulfurization apparatus, and the CO 2 chemical absorption facility.
  • An exhaust gas treatment system comprising a catalyst device for oxidizing mercury in exhaust gas between a heat exchanger and the CO 2 chemical absorption facility.
  • a catalyst having a function of oxidizing Hg is installed between a wet flue gas desulfurization device and a CO 2 chemical absorption facility, and the metal in the exhaust gas re-released from the wet flue gas desulfurization device by the oxidation catalyst.
  • exhaust gas may be circulated through a catalyst layer having a function of oxidizing metallic mercury into oxidized mercury.
  • a composition comprising oxides of (i) titanium (Ti), (ii) molybdenum (Mo) and / or tungsten (W), (iii) vanadium (V), and (iv) phosphorus (P).
  • the atomic ratio of Ti: (Mo and / or W): V is 85 to 97.5: 2 to 10: 0.5 to 10, and the atomic ratio of P / (sum of Mo and / or W and V) is 0.5.
  • the catalyst (PCT / JP2007 / 067496) which is ⁇ 1.5 is mentioned.
  • Oxidized mercury is removed together with CO 2 in the downstream CO 2 chemical absorption facility, but the CO 2 absorbent used in the CO 2 chemical absorption facility may be a conventionally used one such as alkanolamine. .
  • FIG. 4 An embodiment of the exhaust gas treatment system of the present invention is shown in FIG.
  • the difference between the exhaust gas treatment system of the present invention and the conventional system shown in FIG. 4 is that mercury is exchanged between the wet flue gas desulfurization apparatus 7 and the CO 2 chemical absorption equipment 11 in the form of highly water-soluble mercury oxide.
  • a mercury oxidation means (catalyst device) 10 made of an oxidation catalyst having a function of oxidizing the exhaust gas is provided, in addition, a heat exchanger 4 for recovering exhaust heat from the exhaust gas, and a mercury oxidation means (catalyst device) 10 by the recovered exhaust heat
  • a heat exchanger 8 for exhaust gas reheating that raises the inlet gas temperature to the activation temperature of the oxidation reaction or higher is installed, and the mercury metal is converted to mercury oxide in the exhaust gas at the inlet of the CO 2 chemical absorption facility 11, that is, at the outlet of the wet desulfurization apparatus is converted to the form, introducing a water-soluble mercury oxide to CO 2 chemical absorption equipment 11 is to the oxidation of mercury was to absorption removed with CO 2 by the CO 2 absorbing liquid.
  • exhaust gas from a boiler 1 is introduced into a denitration device 2, and after removing nitrogen oxides, combustion air used in the boiler 1 is heated by the exhaust gas in an air preheater 3.
  • the exhaust gas discharged from the air preheater 3 is introduced into the heat recovery unit 4, and heat is recovered and cooled by a heat medium circulating in the heat recovery unit.
  • the exhaust gas discharged from the heat recovery unit 4 is introduced into the dust collecting device 5, and after collecting the dust, the pressure is increased by the induction fan 6 and introduced into the wet desulfurization device 7.
  • Sulfur oxides in the exhaust gas are removed by the wet desulfurization device 7, and the exhaust gas discharged from the wet desulfurization device 7 is heated by the reheater 8 by the heat recovered by the heat recovery device 4.
  • Exhaust gas discharged from ⁇ heater 8 is introduced into the catalyst device 10 having a function of oxidizing the Hg, after oxidizing the metal Hg, is sent to the CO 2 chemical absorption equipment 11, Hg oxidized forms together with CO 2 Is absorbed and removed.
  • the exhaust gas from which CO 2 and the oxidized form of Hg have been removed is discharged from the chimney 13 into the atmosphere by the desulfurization fan 12.
  • the heat recovery device 4 includes a heat medium circulation pipe 14 that circulates the heat medium between the heat recovery device 4 and the reheater 8, and the heat medium is circulated by a heat medium circulation pump 15.
  • the exhaust gas temperature introduced into the catalyst device 10 via the heat recovery device 4 can be optimized by providing a flow rate adjusting valve in the heat medium circulation pipe 14 and adjusting the flow rate of the circulating heat medium.
  • FIG. 2 is an explanatory view of an exhaust gas treatment system showing another embodiment of the present invention.
  • chlorine injection means 16 is provided in the exhaust gas downstream of the catalyst device 10 and downstream of the wet desulfurization device 7 in the system of FIG.
  • the metal mercury in the exhaust gas can be converted into a form of mercury oxide (HgCl 2 .
  • HgCl 2 mercury oxide
  • the chlorine in the exhaust gas discharged from the boiler is removed by the wet desulfurization device 7, depending on the fuel properties and the amount of mercury in the exhaust gas, there may be a shortage of chlorine necessary for mercury oxidation.
  • chlorine necessary for mercury oxidation is injected into the flue between the wet desulfurization apparatus 7 and the catalyst apparatus 10.
  • FIG. 3 is an explanatory view of an exhaust gas treatment system showing still another embodiment of the present invention. 1 differs from the system of FIG. 1 in order to cope with a case where the heat source of the catalyst device 10 is insufficient due to a decrease in temperature of the exhaust gas at the outlet of the boiler or the like, an auxiliary exhaust gas heater 17 using steam as a heat source upstream of the reheater 8. Is installed. By installing the steam heater 17, it is possible to make up for a heat source that is insufficient with the catalyst 10, and to avoid unoxidized mercury in the catalyst device 10. Since the steam used here is also related to the plant efficiency, it is preferable to control the steam amount to an optimum steam amount necessary for maintaining the activity in the catalyst device 10 according to the exhaust gas temperature at the boiler outlet.
  • a heater using steam as a heat source is provided in a heat medium circulation pipe 14 that transports exhaust heat between the heat recovery device 4 and the reheater 8. Even if 18 is provided, the same effect can be obtained.
  • the metal Hg of re-emitted by the flue gas in a wet flue gas desulfurization apparatus the catalyst having a function to oxidize Hg, CO 2 chemical in the form of easily removable water-soluble chloride Hg Since it can be removed together with CO 2 at the absorption facility, it becomes possible to remove Hg in the exhaust gas with high efficiency and to respond to the strengthening of Hg emission regulations.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Treating Waste Gases (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Chimneys And Flues (AREA)
  • Gas Separation By Absorption (AREA)

Abstract

Disclosed is an emission gas processing system provided with a wet flue gas desulfurization device and a CO2 chemical absorption device, wherein issues caused by mercury in emission gas are solved and release of metallic mercury to the outside is prevented. The gas emission processing system is provided with: an air preheater (3) which heats combustion air for a fossil fuel combustion furnace; a dust-collection device (5) positioned in the wake flow of the air preheater (3); a wet desulfurization device (7) that provides a wet treatment of sulfur oxides in the emission gas; a CO2 chemical absorption device (11) that absorbs and separates CO2 from the emission gas; a heat exchanger for emission gas heat recovery (4) disposed between the air preheater (3) and the dust-collection device (5); a heat exchanger for reheating emission gas (8), that increases the emission gas temperature by using the heat recovered by the heat exchanger for emission gas heat recovery (4), disposed between the wet desulfurization device (7) and the CO2 chemical absorption device (11); and a catalyst (10) for oxidizing mercury in emission gas, disposed between the heat exchanger for reheating emission gas (8) and the CO2 chemical absorption device (11).

Description

二酸化炭素化学吸収設備を有する排ガス処理システムExhaust gas treatment system with carbon dioxide chemical absorption equipment
　本発明は、二酸化炭素CO2化学吸収設備を有する排ガス処理システムに係り、特に湿式排煙脱硫装置、CO2化学吸収設備および排ガス中の水銀を除去する触媒装置を備えた排ガス処理システムに関する。 The present invention relates to an exhaust gas treatment system having a carbon dioxide CO 2 chemical absorption facility, and more particularly to an exhaust gas treatment system including a wet flue gas desulfurization device, a CO 2 chemical absorption facility, and a catalyst device for removing mercury in the exhaust gas.
　一般に、石炭焚きボイラ等から排出される排ガス中には窒素酸化物、硫黄酸化物、煤塵、および水銀等の重金属が含まれているため、前記石炭焚きボイラ等の下流側に排煙処理システムを設置し、排ガス中の前記有害物質を除去した後、クリーンなガスとして大気に放出している。また、近年の地球温暖化問題に関し、排ガス中から二酸化炭素(CO2)の分離回収を行う必要も生じている。 In general, exhaust gases discharged from coal-fired boilers and the like contain heavy metals such as nitrogen oxides, sulfur oxides, dust, and mercury. After installing and removing the harmful substances in the exhaust gas, it is released into the atmosphere as clean gas. In addition, regarding the recent global warming problem, it has become necessary to separate and recover carbon dioxide (CO 2 ) from exhaust gas.
　図４に従来の排煙処理システムおよびCO2回収システムの一例を示す。ボイラ１から排出される燃焼排ガスは、脱硝装置２で窒素酸化物および水銀を除去した後、空気予熱器３を経て、集塵装置５で排ガス中の煤塵を除去し、さらに誘引ファン６で昇圧した後、湿式排煙脱硫装置７で硫黄酸化物が除去される。窒素酸化物、水銀および二酸化硫黄が除去された後の排ガスは、CO2化学吸収設備１１に送られ、CO2の化学吸収により、排ガス中からCO2の分離、回収が行われる。 FIG. 4 shows an example of a conventional smoke treatment system and a CO 2 recovery system. The combustion exhaust gas discharged from the boiler 1 removes nitrogen oxides and mercury by the denitration device 2, passes through the air preheater 3, removes the dust in the exhaust gas by the dust collector 5, and further increases the pressure by the induction fan 6. After that, the sulfur oxide is removed by the wet flue gas desulfurization apparatus 7. Nitrogen oxides, the exhaust gas after the mercury and sulfur dioxide has been removed, is sent to the CO 2 chemical absorption equipment 11, the chemical absorption of CO 2, separated from the exhaust gas of CO 2, the recovery is performed.
　排ガス中の水銀(Hg)は、脱硝装置２を構成する脱硝触媒の酸化反応により、排ガス中の塩素(Cl)と反応し、酸化水銀(HgCl2)の形態に変換されるが、水銀除去性能を高めるために、水銀の酸化能力を高める一方、二酸化硫黄(SO2)の酸化によりSO3を増加させないように、SO2酸化能力を低く抑えた触媒組成を持つ触媒が脱硝触媒として使用される場合もある。触媒の酸化能力により水溶性の高い酸化水銀HgCl2の形態に変換された水銀は、主として湿式排煙脱硫装置７の石灰石スラリー吸収液により排ガス中から吸収除去される。 Mercury (Hg) in the exhaust gas reacts with chlorine (Cl) in the exhaust gas by the oxidation reaction of the denitration catalyst that constitutes the denitration device 2 and is converted to the form of mercury oxide (HgCl 2 ). In order to increase the oxidation performance of mercury, a catalyst having a catalyst composition with a low SO 2 oxidation capability is used as a denitration catalyst so as not to increase SO 3 due to oxidation of sulfur dioxide (SO 2 ) In some cases. Mercury converted into the form of mercury oxide HgCl 2 having high water solubility due to the oxidation ability of the catalyst is mainly absorbed and removed from the exhaust gas by the limestone slurry absorbent of the wet flue gas desulfurization apparatus 7.
　燃料の燃焼用に空気を使用する一般的なボイラ等の燃焼炉において、排ガス中からCO2を回収するためには、窒素分が多いため、圧縮機を使用して排ガスから直接CO2を分離することができない。このため、アルカノールアミンなどのアミン化合物の水溶液をCO2吸収液として排ガスと気液接触させ、吸収液にCO2を吸収させることにより排ガス中からCO2の分離回収を行う方法がとられている。 In a combustion furnace such as a general boiler that uses air for the combustion of fuel, in order to recover CO 2 from the exhaust gas, since there is a large amount of nitrogen, the compressor is used to separate CO 2 directly from the exhaust gas. Can not do it. For this reason, a method has been adopted in which an aqueous solution of an amine compound such as alkanolamine is brought into gas-liquid contact with exhaust gas as a CO 2 absorbing solution, and CO 2 is separated and recovered from the exhaust gas by absorbing the CO 2 into the absorbing solution. .
　図５にこのようなアミン吸収液によるCO2化学吸収設備の一例を示す。排ガス２０は吸収塔２５に導入され、アミン吸収液との接触によりCO2が除去された後、脱CO2ガス２７として外部に排出される。一方、CO2を吸収したアミン吸収液は吸収液循環ポンプ２８により再生塔２６に導入され、ここで蒸気により加熱され、アミンとCO2が分離されて高純度のCO2ガス２９として回収される。再生塔２６内の加熱用蒸気は、リボイラ３０でアミン吸収液をスチーム３２で加熱することにより得られる。また排ガス中の硫黄酸化物が吸収されると、アミンと化合物を形成するため、リクレイマー３１で炭酸ナトリウムなどのアルカリ塩を添加し、スチーム３２で加熱することにより、アミンを再生している。再生されたアミン吸収液は再生塔２６の底部から熱交換器を経由し、ポンプ３３により吸収塔２５に戻される。 FIG. 5 shows an example of a CO 2 chemical absorption facility using such an amine absorbing solution. The exhaust gas 20 is introduced into the absorption tower 25, and after CO 2 is removed by contact with the amine absorbing solution, it is discharged to the outside as de-CO 2 gas 27. On the other hand, the amine absorption liquid that has absorbed CO 2 is introduced into the regeneration tower 26 by the absorption liquid circulation pump 28, where it is heated by steam, and the amine and CO 2 are separated and recovered as high-purity CO 2 gas 29. . The heating steam in the regeneration tower 26 is obtained by heating the amine absorbing liquid with the steam 32 using the reboiler 30. In addition, when sulfur oxides in the exhaust gas are absorbed, a compound is formed with the amine, so that an alkali salt such as sodium carbonate is added by the reclaimer 31 and heated by the steam 32 to regenerate the amine. The regenerated amine absorption liquid is returned from the bottom of the regeneration tower 26 to the absorption tower 25 by a pump 33 via a heat exchanger.
　従来の排煙処理システムでは、排ガス中の水銀のうち２価水銀(Hg2+)は、湿式脱硫装置７において石灰石スラリー吸収液に吸収されることにより、排ガス中から除去される。しかしながら、石灰石スラリー液中に吸収された２価水銀(Hg2+)は必ずしも安定しておらず、吸収液のpH等の運転条件の変化により金属水銀(HgO)の形態に還元され、排ガス中に再放出されてしまうという問題があった。 In the conventional flue gas treatment system, divalent mercury (Hg 2+ ) out of mercury in the exhaust gas is removed from the exhaust gas by being absorbed by the limestone slurry absorbent in the wet desulfurization apparatus 7. However, divalent mercury (Hg 2+ ) absorbed in the limestone slurry is not always stable and is reduced to metallic mercury (HgO) due to changes in operating conditions such as pH of the absorbing solution. There was a problem of being released again.
　また従来の排煙処理システムでは、湿式脱硫装置７後流の排ガス中の水銀はほぼすべて金属水銀(Hg)の形態となるが、CO2化学吸収設備も含め、従来の設備ではこの金属水銀を除去できる構成要素は備えていない。このため、湿式脱硫装置の吸収液（石灰石スラリー）に金属沈殿剤を添加し、液中の金属水銀を固定化させる必要があった。しかしながら、湿式脱硫装置においては、石灰石スラリーと硫黄酸化物の反応により石膏が副生物として生成されるため、この石膏中に有害物の水銀が含有されてしまうという問題を生じる。湿式脱硫装置で生成される石膏は、石膏ボードやセメント原料として有効利用されているが、水銀の含有によりその有効利用が困難となり、廃棄処理を行うとしても、石膏中の水銀が気化して再び大気中に放出されてしまうという問題がある。 In the conventional flue gas treatment system, almost all mercury in the exhaust gas after the wet desulfurization unit 7 is in the form of metallic mercury (Hg). However, conventional equipment, including CO 2 chemical absorption equipment, uses this metallic mercury. There are no components that can be removed. For this reason, it was necessary to add a metal precipitant to the absorption liquid (limestone slurry) of the wet desulfurization apparatus to fix the metal mercury in the liquid. However, in the wet desulfurization apparatus, gypsum is generated as a by-product due to the reaction between the limestone slurry and the sulfur oxide, which causes a problem that harmful mercury is contained in the gypsum. Gypsum produced by wet desulfurization equipment is effectively used as a raw material for gypsum board and cement, but its effective use becomes difficult due to the inclusion of mercury, and even if it is disposed of, the mercury in the gypsum vaporizes again. There is a problem of being released into the atmosphere.
　本発明の課題は、湿式排煙脱硫設備とCO2化学吸収設備を備えた排ガス処理システムにおいて、排ガス中の水銀による上記問題を解決し、金属水銀の外部への放出を防止した排ガス処理システムを提供することである。 An object of the present invention is to provide an exhaust gas treatment system equipped with a wet flue gas desulfurization facility and a CO 2 chemical absorption facility that solves the above-mentioned problems caused by mercury in the exhaust gas and prevents the release of metallic mercury to the outside. Is to provide.
　上記課題を達成するため、本願で特許請求される発明は以下のとおりである。
（１）化石燃料の燃焼炉の燃焼用空気を加熱する空気予熱器と、該空気予熱器の後流に設置された、排ガス中の煤塵を捕集する集塵装置と、排ガス中の硫黄酸化物を湿式処理する湿式脱硫装置と、排ガス中からCO2を吸収分離するCO2化学吸収設備を備えた排ガス処理システムであって、前記空気予熱器と集塵装置の間に排ガス熱回収用熱交換器と、湿式脱硫装置とCO2化学吸収設備の間に前記熱回収用熱交換器で回収した熱によって排ガス温度を昇温する排ガス再加熱用熱交換器をそれぞれ設け、該排ガス再加熱用熱交換器と前記CO2化学吸収設備との間に排ガス中の水銀を酸化するための触媒装置を設けたこと特徴とする排ガス処理システム。
（２）前記湿式脱硫装置の後流で、前期触媒装置の前流に塩素注入装置を設けたことを特徴とする（１）記載のシステム。
（３）前記排ガス再加熱用熱交換器の前流または後流に、蒸気を熱源とした補助排ガス加熱器を設けたことを特徴とする（１）または（２）記載の排ガス処理システム。
（４）前記熱回収用熱交換器で排ガスから回収した排熱を熱媒により回収し、該熱媒を排ガス再加熱器用熱交換器に移送する熱媒ラインと、該熱媒ラインに設けられた蒸気を熱源とするヒータとを備えたことを特徴とする（１）ないし（３）のいずれかに記載の排ガス処理システム。 In order to achieve the above object, the invention claimed in the present application is as follows.
(1) An air preheater that heats combustion air in a fossil fuel combustion furnace, a dust collector that is installed downstream of the air preheater and collects dust in the exhaust gas, and sulfur oxidation in the exhaust gas An exhaust gas treatment system equipped with a wet desulfurization apparatus for wet processing of substances and a CO 2 chemical absorption facility for absorbing and separating CO 2 from the exhaust gas, wherein the heat for exhaust gas heat recovery is provided between the air preheater and the dust collector. An exhaust gas reheating heat exchanger that raises the exhaust gas temperature by heat recovered by the heat recovery heat exchanger is provided between the exchanger, the wet desulfurization apparatus, and the CO 2 chemical absorption facility. An exhaust gas treatment system comprising a catalyst device for oxidizing mercury in exhaust gas between a heat exchanger and the CO 2 chemical absorption facility.
(2) The system according to (1), characterized in that a chlorine injection device is provided downstream of the wet desulfurization device and upstream of the previous catalyst device.
(3) The exhaust gas treatment system according to (1) or (2), wherein an auxiliary exhaust gas heater using steam as a heat source is provided in the upstream or downstream of the exhaust gas reheating heat exchanger.
(4) A heat medium line for recovering exhaust heat recovered from exhaust gas by the heat recovery heat exchanger with a heat medium, and transferring the heat medium to a heat exchanger for exhaust gas reheater; and a heat medium line. The exhaust gas treatment system according to any one of (1) to (3), further comprising: a heater using a vapor as a heat source.
　本発明によれば、湿式排煙脱硫装置とCO2化学吸収設備の間にHgを酸化させる機能を持つ触媒を設置し、該酸化触媒で湿式排煙脱硫装置から再放出された排ガス中の金属Hgを、除去しやすい水溶性の塩化Hgの形態に酸化させ、CO2化学吸収設備でCO2と同時に除去することにより、Hg排出規制強化に対応した高Hg除去システムとすることが可能となる。 According to the present invention, a catalyst having a function of oxidizing Hg is installed between a wet flue gas desulfurization device and a CO 2 chemical absorption facility, and the metal in the exhaust gas re-released from the wet flue gas desulfurization device by the oxidation catalyst. By oxidizing Hg to form water-soluble chloride Hg that is easy to remove and simultaneously removing CO 2 with a CO 2 chemical absorption facility, it becomes possible to achieve a high Hg removal system that complies with stricter Hg emission regulations. .
本発明の実施例を示す排煙処理システムの説明図。Explanatory drawing of the flue gas processing system which shows the Example of this invention. 本発明の他の実施例を示す排煙処理システムの説明図。Explanatory drawing of the flue gas processing system which shows the other Example of this invention. 本発明の他の実施例を示す排煙処理システムの説明図。Explanatory drawing of the flue gas processing system which shows the other Example of this invention. 従来の排ガス処理システムの説明図。Explanatory drawing of the conventional waste gas treatment system. 従来のCO2化学吸収設備の一例を示す説明図。Explanatory view showing an example of a conventional CO 2 chemical absorption equipment.
　本発明において、排ガス中の水銀を酸化するための触媒装置としては、例えば、金属水銀を酸化形態の水銀に酸化する機能を有する触媒層に排ガスを流通させるものでよいが、前記触媒としては、例えば(i)チタン(Ti)、(ii)モリブデン(Mo)及び／またはタングステン(W)、(iii)バナジウム(V)、及び(iv)リン(P)の各酸化物からなる組成物であって、Ti:(Mo及び／またはW):Vの原子比が85～97.5：2～10：0.5～10であり、かつP/(Mo及び／またはWとVとの総和）原子比が0.5～1.5である触媒（PCT/JP2007/067496）が挙げられる。酸化された水銀は、後流のCO2化学吸収設備でCO2と共に除去されるが、CO2化学吸収設備に用いるCO2吸収剤としては、アルカノールアミン等の従来から使用されているものでよい。 In the present invention, as a catalyst device for oxidizing mercury in exhaust gas, for example, exhaust gas may be circulated through a catalyst layer having a function of oxidizing metallic mercury into oxidized mercury. For example, a composition comprising oxides of (i) titanium (Ti), (ii) molybdenum (Mo) and / or tungsten (W), (iii) vanadium (V), and (iv) phosphorus (P). The atomic ratio of Ti: (Mo and / or W): V is 85 to 97.5: 2 to 10: 0.5 to 10, and the atomic ratio of P / (sum of Mo and / or W and V) is 0.5. The catalyst (PCT / JP2007 / 067496) which is ~ 1.5 is mentioned. Oxidized mercury is removed together with CO 2 in the downstream CO 2 chemical absorption facility, but the CO 2 absorbent used in the CO 2 chemical absorption facility may be a conventionally used one such as alkanolamine. .
　本発明の排ガス処理システムの一実施例を図１に示す。本発明の排ガス処理システムと、図４に示した従来のシステムとの相違点は、湿式排煙脱硫装置７とCO2化学吸収設備１１の間に、水銀を、高い水溶性の酸化水銀の形態に酸化させる機能を持つ酸化触媒からなる水銀酸化手段（触媒装置）１０を設け、加えて排ガス中から排熱を回収する熱交換器４と、回収した排熱により水銀酸化手段（触媒装置）１０の入口ガス温度を酸化反応の活性温度以上に昇温させる排ガス再加熱用熱交換器８を設置し、CO2化学吸収設備１１の入口、すなわち湿式脱硫装置出口の排ガス中の金属水銀を酸化水銀の形態に変換させ、水溶性の酸化水銀をCO2化学吸収設備１１に導入し、該酸化水銀をCO2吸収液によりCO2と共に吸収除去をするようにしたことである。 An embodiment of the exhaust gas treatment system of the present invention is shown in FIG. The difference between the exhaust gas treatment system of the present invention and the conventional system shown in FIG. 4 is that mercury is exchanged between the wet flue gas desulfurization apparatus 7 and the CO 2 chemical absorption equipment 11 in the form of highly water-soluble mercury oxide. A mercury oxidation means (catalyst device) 10 made of an oxidation catalyst having a function of oxidizing the exhaust gas is provided, in addition, a heat exchanger 4 for recovering exhaust heat from the exhaust gas, and a mercury oxidation means (catalyst device) 10 by the recovered exhaust heat A heat exchanger 8 for exhaust gas reheating that raises the inlet gas temperature to the activation temperature of the oxidation reaction or higher is installed, and the mercury metal is converted to mercury oxide in the exhaust gas at the inlet of the CO 2 chemical absorption facility 11, that is, at the outlet of the wet desulfurization apparatus is converted to the form, introducing a water-soluble mercury oxide to CO 2 chemical absorption equipment 11 is to the oxidation of mercury was to absorption removed with CO 2 by the CO 2 absorbing liquid.
　図１において、ボイラ１からの排ガスは脱硝装置２に導入され、窒素酸化物を除去した後、空気予熱器３においてボイラ１で使用される燃焼用空気を排ガスにより加熱される。次いで該空気予熱器３から排出された排ガスは、熱回収器４に導入され、熱回収器内を循環している熱媒により熱を回収され冷却される。該熱回収器４から排出された排ガスは、集塵装置５に導入され、煤塵を捕集した後、誘引ファン６で昇圧され、湿式脱硫装置７に導入される。該湿式脱硫装置７で排ガス中の硫黄酸化物が除去され、該湿式脱硫装置７から排出された排ガスは前記熱回収器４で回収した熱により再加熱器８で昇温される。該再加熱器８から排出された排ガスは、Hgを酸化させる機能を持つ触媒装置１０に導入され、金属Hgを酸化した後、CO2化学吸収設備１１に送られ、CO2と共に酸化形態のHgが吸収除去される。CO2及び酸化形態のHgが除去された排ガスは、脱硫ファン１２により煙突１３から大気中に排出される。前記熱回収器４は、再加熱器８との間に熱媒を循環させる熱媒循環配管１４を備え、 熱媒は熱媒循環ポンプ１５で循環される構成となっている。この熱媒循環配管１４に流量調節弁を設け、循環する熱媒の流量を調節することにより、熱回収器４を介して触媒装置１０に導入される排ガス温度を最適化することができる。 In FIG. 1, exhaust gas from a boiler 1 is introduced into a denitration device 2, and after removing nitrogen oxides, combustion air used in the boiler 1 is heated by the exhaust gas in an air preheater 3. Next, the exhaust gas discharged from the air preheater 3 is introduced into the heat recovery unit 4, and heat is recovered and cooled by a heat medium circulating in the heat recovery unit. The exhaust gas discharged from the heat recovery unit 4 is introduced into the dust collecting device 5, and after collecting the dust, the pressure is increased by the induction fan 6 and introduced into the wet desulfurization device 7. Sulfur oxides in the exhaust gas are removed by the wet desulfurization device 7, and the exhaust gas discharged from the wet desulfurization device 7 is heated by the reheater 8 by the heat recovered by the heat recovery device 4. Exhaust gas discharged from該再heater 8 is introduced into the catalyst device 10 having a function of oxidizing the Hg, after oxidizing the metal Hg, is sent to the CO 2 chemical absorption equipment 11, Hg oxidized forms together with CO 2 Is absorbed and removed. The exhaust gas from which CO 2 and the oxidized form of Hg have been removed is discharged from the chimney 13 into the atmosphere by the desulfurization fan 12. The heat recovery device 4 includes a heat medium circulation pipe 14 that circulates the heat medium between the heat recovery device 4 and the reheater 8, and the heat medium is circulated by a heat medium circulation pump 15. The exhaust gas temperature introduced into the catalyst device 10 via the heat recovery device 4 can be optimized by providing a flow rate adjusting valve in the heat medium circulation pipe 14 and adjusting the flow rate of the circulating heat medium.
　図２は、本発明の他の実施例を示す排ガス処理システムの説明図である。このシステムは、図１のシステムにおいて、触媒装置１０の前流で、かつ湿式脱硫装置７の後流排ガス中に塩素注入手段１６を設けたものである。このように湿式脱硫装置７の後流で、触媒装置１０に導入される排ガス中に塩素を注入することにより、排ガス中の金属水銀を酸化水銀の形態(HgCl2に変換することができる。これはボイラから排出される排ガス中の塩素が湿式脱硫装置7により除去されるため、燃料性状や排ガス中の水銀量によっては、水銀の酸化に必要となる塩素が不足する場合が起こりえる。この場合においても水銀を高効率で除去するために、湿式脱硫装置７と触媒装置１０の間の煙道中に水銀酸化に必要な塩素を注入するように構成したものである。 FIG. 2 is an explanatory view of an exhaust gas treatment system showing another embodiment of the present invention. In this system, chlorine injection means 16 is provided in the exhaust gas downstream of the catalyst device 10 and downstream of the wet desulfurization device 7 in the system of FIG. Thus, by injecting chlorine into the exhaust gas introduced into the catalyst device 10 in the downstream of the wet desulfurization device 7, the metal mercury in the exhaust gas can be converted into a form of mercury oxide (HgCl 2 . Since the chlorine in the exhaust gas discharged from the boiler is removed by the wet desulfurization device 7, depending on the fuel properties and the amount of mercury in the exhaust gas, there may be a shortage of chlorine necessary for mercury oxidation. Also, in order to remove mercury with high efficiency, chlorine necessary for mercury oxidation is injected into the flue between the wet desulfurization apparatus 7 and the catalyst apparatus 10.
　図３は、本発明のさらに他の実施例を示す排ガス処理システムの説明図である。図１のシステムと異なる点は、ボイラ出口排ガスの温度低下等により触媒装置１０の熱源が不足する場合に対処するために、再加熱器８の上流に蒸気を熱源とした補助用排ガス加熱器１７を設置したものである。蒸気式加熱器１７を設置することにより、触媒１０で不足する熱源を補うことができ、該触媒装置１０での水銀の未酸化を避けることができる。ここで使用する蒸気は、プラント効率にも関わるため、ボイラ出口排ガス温度に応じて、触媒装置１０での活性を維持するために必要な最適蒸気量に制御することが好ましい。 FIG. 3 is an explanatory view of an exhaust gas treatment system showing still another embodiment of the present invention. 1 differs from the system of FIG. 1 in order to cope with a case where the heat source of the catalyst device 10 is insufficient due to a decrease in temperature of the exhaust gas at the outlet of the boiler or the like, an auxiliary exhaust gas heater 17 using steam as a heat source upstream of the reheater 8. Is installed. By installing the steam heater 17, it is possible to make up for a heat source that is insufficient with the catalyst 10, and to avoid unoxidized mercury in the catalyst device 10. Since the steam used here is also related to the plant efficiency, it is preferable to control the steam amount to an optimum steam amount necessary for maintaining the activity in the catalyst device 10 according to the exhaust gas temperature at the boiler outlet.
　また、補助用排ガス加熱器１７の代りに、またはこれに追加して、熱回収器４と再加熱器８の間で排熱の輸送を行う熱媒循環配管１４に、蒸気を熱源としたヒータ１８を設けても同様の効果が得られる。 Further, instead of or in addition to the auxiliary exhaust gas heater 17, a heater using steam as a heat source is provided in a heat medium circulation pipe 14 that transports exhaust heat between the heat recovery device 4 and the reheater 8. Even if 18 is provided, the same effect can be obtained.
　以上のように本発明によれば、湿式排煙脱硫装置で再放出した排ガス中の金属Hgを、Hgを酸化させる機能を持つ触媒により、除去しやすい水溶性の塩化Hgの形態としてCO2化学吸収設備でCO2と共に除去することができるため、排ガス中のHgを高効率で除去し、Hg排出規制強化に対応することが可能となる。 According to the present invention as described above, the metal Hg of re-emitted by the flue gas in a wet flue gas desulfurization apparatus, the catalyst having a function to oxidize Hg, CO 2 chemical in the form of easily removable water-soluble chloride Hg Since it can be removed together with CO 2 at the absorption facility, it becomes possible to remove Hg in the exhaust gas with high efficiency and to respond to the strengthening of Hg emission regulations.

Claims (4)

  1. 　化石燃料の燃焼炉の燃焼用空気を加熱する空気予熱器と、該空気予熱器の後流に設置された、排ガス中の煤塵を捕集する集塵装置と、排ガス中の硫黄酸化物を湿式処理する湿式脱硫装置と、排ガス中からCO2を吸収分離するCO2化学吸収設備を備えた排ガス処理システムであって、前記空気予熱器と集塵装置の間に排ガス熱回収用熱交換器と、湿式脱硫装置とCO2化学吸収設備の間に前記熱回収用熱交換器で回収した熱によって排ガス温度を昇温する排ガス再加熱用熱交換器をそれぞれ設け、該排ガス再加熱用熱交換器と前記CO2化学吸収設備との間に排ガス中の水銀を酸化するための触媒装置を設けたこと特徴とする排ガス処理システム。 An air preheater that heats the combustion air of the fossil fuel combustion furnace, a dust collector that is installed downstream of the air preheater to collect the dust in the exhaust gas, and the sulfur oxide in the exhaust gas is wet An exhaust gas treatment system comprising a wet desulfurization device to be treated and a CO 2 chemical absorption facility for absorbing and separating CO 2 from the exhaust gas, the exhaust gas heat recovery heat exchanger between the air preheater and the dust collector An exhaust gas reheating heat exchanger that raises the exhaust gas temperature by heat recovered by the heat recovery heat exchanger between the wet desulfurization apparatus and the CO 2 chemical absorption facility, and the exhaust gas reheating heat exchanger An exhaust gas treatment system comprising a catalyst device for oxidizing mercury in exhaust gas between the CO 2 chemical absorption facility and the CO 2 chemical absorption facility.
  2. 　前記湿式脱硫装置の後流で、前期触媒装置の前流に塩素注入装置を設けたことを特徴とする請求項1記載のシステム。 The system according to claim 1, wherein a chlorine injection device is provided downstream of the wet desulfurization device and upstream of the previous catalyst device.
  3. 　前記排ガス再加熱用熱交換器の前流または後流に、蒸気を熱源とした補助排ガス加熱器を設けたことを特徴とする請求項1または2記載の排ガス処理システム。 3. The exhaust gas treatment system according to claim 1, wherein an auxiliary exhaust gas heater using steam as a heat source is provided in the upstream or downstream of the exhaust gas reheating heat exchanger.
  4. 　前記熱回収用熱交換器で排ガスから回収した排熱を熱媒により回収し、該熱媒を排ガス再加熱器用熱交換器に移送する熱媒ラインと、該熱媒ラインに設けられた蒸気を熱源とするヒータとを備えたことを特徴とする請求項1ないし３のいずれかに記載の排ガス処理システム。 The exhaust heat recovered from the exhaust gas by the heat recovery heat exchanger is recovered by a heat medium, the heat medium line for transferring the heat medium to the heat exchanger for the exhaust gas reheater, and the steam provided in the heat medium line The exhaust gas treatment system according to any one of claims 1 to 3, further comprising a heater as a heat source.
PCT/JP2011/060818 2010-05-12 2011-05-11 Emission gas processing system with carbon dioxide chemical absorption device WO2011142376A1 (en)

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