WO2014041951A1 - Système de traitement du mercure contenu dans un gaz d'échappement - Google Patents

Système de traitement du mercure contenu dans un gaz d'échappement Download PDF

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Publication number
WO2014041951A1
WO2014041951A1 PCT/JP2013/071886 JP2013071886W WO2014041951A1 WO 2014041951 A1 WO2014041951 A1 WO 2014041951A1 JP 2013071886 W JP2013071886 W JP 2013071886W WO 2014041951 A1 WO2014041951 A1 WO 2014041951A1
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Prior art keywords
mercury
exhaust gas
treatment system
extracted
absorption liquid
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PCT/JP2013/071886
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English (en)
Japanese (ja)
Inventor
笙子 永江
晴治 香川
立人 長安
鵜飼　展行
岡本　卓也
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三菱重工業株式会社
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Publication of WO2014041951A1 publication Critical patent/WO2014041951A1/fr

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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
    • B01D53/346—Controlling the process
    • 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
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8621—Removing nitrogen compounds
    • B01D53/8625—Nitrogen oxides
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/10—Oxidants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2062—Ammonia
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/40—Alkaline earth metal or magnesium compounds
    • B01D2251/404—Alkaline earth metal or magnesium compounds of calcium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/50—Zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • 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
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/20—Sulfur; Compounds thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/60—Heavy metals; Compounds thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2219/00—Treatment devices
    • F23J2219/40—Sorption with wet devices, e.g. scrubbers

Definitions

  • the present invention relates to a mercury treatment system in exhaust gas capable of removing mercury in exhaust gas to an extremely low concentration.
  • the exhaust gas generated when burning coal-fired exhaust gas or heavy oil may contain metal mercury (Hg 0 ) in addition to soot, sulfur oxide (SOx), and nitrogen oxide (NOx).
  • Hg 0 metal mercury
  • SOx sulfur oxide
  • NOx nitrogen oxide
  • various devices and methods for treating metallic mercury (Hg 0 ) have been devised in combination with a denitration device that reduces NOx and a wet desulfurization device that uses an alkaline absorbent as an SOx absorbent.
  • NH 3 undergoes a reduction reaction with NOx in the exhaust gas as represented by the following formula (1), and HCl represents Hg in the exhaust gas as represented by the following formula (2).
  • HCl represents Hg in the exhaust gas as represented by the following formula (2).
  • 0 and the oxidation reaction proceed.
  • NH 3 is reduced and denitrated on the denitration catalyst, and metal mercury (Hg 0 ) is oxidized to form water-soluble mercury chloride (HgCl 2 ), and then HgCl is used in a desulfurization apparatus using a wet lime gypsum method installed on the downstream side. 2 is dissolved in the gypsum slurry solution to remove mercury contained in the exhaust gas.
  • the present invention has been made in view of the above, and at the same time, removes divalent mercury in exhaust gas, and at the same time removes HCl and dust in exhaust gas that cause performance degradation in the process where a desulfurization apparatus is installed.
  • An object of the present invention is to provide a mercury treatment system in exhaust gas that can be used.
  • a first invention of the present invention for solving the above-mentioned problem is a mercury removal system for removing mercury contained in exhaust gas from a boiler, and is a heat exchanger for exchanging heat from the exhaust gas from a boiler. And a mercury collector for removing dust in the exhaust gas, and a mercury absorption tower provided on the downstream side of the dust collector for removing mercury oxide in the exhaust gas with a mercury absorbing liquid.
  • a mercury removal system for removing mercury contained in exhaust gas from a boiler, and is a heat exchanger for exchanging heat from the exhaust gas from a boiler.
  • a mercury collector for removing dust in the exhaust gas
  • a mercury absorption tower provided on the downstream side of the dust collector for removing mercury oxide in the exhaust gas with a mercury absorbing liquid.
  • the exhaust gas further comprises a wet desulfurization device that is provided on the downstream side of the mercury absorption tower and desulfurizes sulfur oxides in the exhaust gas after mercury removal.
  • a wet desulfurization device that is provided on the downstream side of the mercury absorption tower and desulfurizes sulfur oxides in the exhaust gas after mercury removal.
  • a third invention is the denitration which is provided on the upstream side of the heat exchanger in the first or second invention and denitrates nitrogen oxides (NOx) in the exhaust gas and oxidizes metallic mercury (Hg 0 ).
  • a mercury treatment system in exhaust gas characterized by comprising a denitration means having a catalyst.
  • a fourth invention is the mercury treatment system in exhaust gas according to any one of the first to third inventions, wherein the oxidation-reduction state in the mercury absorption tower is judged by oxidation-reduction potential measurement control means. .
  • a fifth invention is the mercury treatment system in exhaust gas according to any one of the first to fourth inventions, wherein the mercury absorption liquid is extracted from the mercury absorption tower, and the extracted mercury absorption liquid is drained. It is in.
  • the mercury absorption liquid is extracted from the mercury absorption tower, the solid content in the extracted mercury absorption liquid is separated, and the mercury absorption after the solid content separation is performed.
  • the present invention is in a mercury treatment system in exhaust gas, wherein the liquid is reused in the mercury absorption tower.
  • a seventh aspect of the present invention is the process according to any one of the first to fourth aspects, wherein the mercury absorption liquid is extracted from the mercury absorption tower, the solid content in the extracted mercury absorption liquid is separated, and the treated water after the solid content separation is separated.
  • a mercury treatment system in exhaust gas characterized by evaporating the gas.
  • a mercury absorption liquid is extracted from the mercury absorption tower, a solid content in the extracted mercury absorption liquid is separated, and treated water after the solid content separation is separated. It is in a mercury treatment system in exhaust gas characterized by treating waste water.
  • the mercury absorbing liquid is extracted from the mercury absorption tower, the solid content in the extracted mercury absorbing liquid is aggregated, and treated water containing aggregates is obtained. It is in a mercury treatment system in exhaust gas characterized by evaporating treatment.
  • the present invention since mercury oxide in the boiler exhaust gas is efficiently removed before being introduced into the desulfurization apparatus, divalent mercury in the exhaust gas can be removed. Moreover, in the process in which the desulfurization apparatus is installed, HCl and dust in the exhaust gas that cause the performance degradation can be removed.
  • FIG. 1 is a schematic diagram showing a mercury treatment system in exhaust gas according to Embodiment 1 of the present invention.
  • FIG. 2 is a schematic view showing a mercury treatment system in exhaust gas according to Embodiment 2 of the present invention.
  • FIG. 3 is a schematic view showing a mercury treatment system in exhaust gas according to Embodiment 3 of the present invention.
  • FIG. 4 is a schematic view showing a mercury treatment system in exhaust gas according to Embodiment 4 of the present invention.
  • FIG. 5 is a schematic view showing a mercury treatment system in exhaust gas according to Embodiment 5 of the present invention.
  • FIG. 6 is a relationship diagram between the ORP value in the mercury absorbing solution and the mercury re-scattering rate.
  • FIG. 7 shows the potential-pH value (Pourbaille diagram) of mercury.
  • FIG. 1 is a schematic view of a mercury treatment system in exhaust gas according to Embodiment 1 of the present invention.
  • the mercury treatment system 10A in the exhaust gas according to the present embodiment is a mercury treatment system in the exhaust gas that removes mercury contained in the exhaust gas 12 from the boiler 11, and is supplied with fuel F.
  • the mercury absorption tower 50 is provided.
  • reference numeral 13 denotes a flue from which exhaust gas is discharged
  • 25 denotes a chimney for discharging the purified exhaust gas to the outside
  • V 0 , V 1 , V 2 denote valves.
  • ammonia (NH 3 ) 14A as denitration aid is added to ammonia (NH 3 ) via the ammonia (NH 3 ) supply line 15A in the exhaust gas flowing through the flue 13 on the upstream side of the denitration device 17.
  • a general device having a reduction denitration catalyst can be used as the denitration device 17, a general device having a reduction denitration catalyst can be used.
  • the reductive denitration catalyst is not particularly limited. For example, a catalyst in which a metal oxide such as W, Sn, In, Co, Ni, Fe, Ni, Ag, or Cu is supported on a support such as zeolite may be used. it can.
  • the amount of the reducing denitration catalyst provided in the denitration device 17 may be increased from the normal amount in order to increase the mercury oxidation efficiency.
  • the ammonia denitrated exhaust gas 12 has a gas temperature of, for example, about 330 ° C. Using the heat of the exhaust gas 12, air (not shown) supplied to the boiler 11 from the outside is separately used by an air heater (AH) 18. Preheated.
  • AH air heater
  • the exhaust gas 12 is introduced into the mercury adsorption tower 50, where the mercury in the exhaust gas 12 is removed with the mercury absorbing solution 51.
  • the top side of the mercury adsorption tower 50 is a nozzle 53 is provided, so that spraying the mercury absorbing liquid 51 to be circulated by a pump (not shown) circulation line L 11.
  • the sprayed mercury absorption liquid 51 is brought into contact with the exhaust gas so that soluble mercury oxide (Hg 2+ ) moves to the mercury absorption liquid 51 side and is dissolved and removed.
  • the mercury absorbent solution 51 water or chelating solution is by using, if necessary, by opening the valve V 1 interposed in introduction line L 12, be added to the oxidant 55 Good.
  • Air may be introduced as the oxidant.
  • the oxidant air is used in the present embodiment, but the present invention is not limited to this.
  • an oxygen-based oxidant such as O 2 , O 3 , H 2 O 2
  • oxygen acids and oxyacid salts such as permanganic acid, chromic acid, chloric acid, hypochlorous acid, perchloric acid, nitric acid, nitrous acid and their salts, chlorine (Cl 2 ), HClO, NaClO, ClO
  • chlorine-based oxidizers polyvalent metal salts such as Fe 3+ , Cu 2+ , and Sn 4+ .
  • an ORP controller 56 for controlling the oxidation-reduction potential (ORP) of the mercury absorbing solution 51 is used.
  • ORP value is +50 mV or more, preferably the ORP value. Is set to +80 mV or more, and more preferably, the supply amount of the oxidizing agent 55 is adjusted so that the ORP value is +100 mV.
  • FIG. 6 is a relationship diagram between the ORP value in the mercury absorbing solution and the mercury re-scattering rate.
  • FIG. 6 shows the relationship between the ratio of metallic mercury in the total mercury in the mercury absorbing solution at 48 ° C. and the ORP value.
  • the vertical axis represents the mercury re-scattering rate of “metal mercury (Hg 0 ) amount / total mercury (Hg total ) amount”
  • the horizontal axis represents the ORP value.
  • the metal mercury is 100%
  • the amount of metal mercury is 0%.
  • the electrode is measured at a temperature of 48 ° C. using silver / silver chloride.
  • Cl - concentration: Hg concentration 13,000: 1.
  • the ORP value is 80 mV, it is almost zero. When the temperature is high, the value tends to be lower.
  • FIG. 7 shows the potential-pH value (Pourbaille diagram) of mercury.
  • the potential-pH value (Pourbaille diagram) of mercury since there is a boundary between the oxidizing environment and the reducing environment when the ORP value is around 90 mV, it is preferably 90 mV or more, more preferably 100 mV or more. It is preferable to control the ORP value.
  • the mercury oxide dissolved in the mercury absorbing liquid 51 is prevented from being re-scattered as metallic mercury, and in the exhaust gas 12 introduced to the desulfurization apparatus 21 side. Mercury is prevented from being accompanied.
  • Mercury absorbing solution 51 obtained by dissolving the oxidized mercury at the mercury adsorption tower 50, every predetermined amount is discharged by opening the interposed a valve V 2 to the collection tank 52 side to the discharge line L 13.
  • the mercury absorbent solution 51 to be replenished separately from introduction line L 14, is introduced required amount of mercury absorption tower 50.
  • the exhaust gas 12 from which the mercury in the exhaust gas 12 has been removed by the mercury absorption tower 50 is then discharged out of the system from the chimney 25 as the purified gas 24.
  • the mercury absorbing solution 51 in which the mercury oxide discharged to the collection tank 52 side is dissolved is sent to a known waste water treatment means for waste water treatment.
  • FIG. 2 is a schematic diagram of a mercury treatment system in exhaust gas according to Embodiment 2 of the present invention.
  • the mercury treatment system 10 ⁇ / b> B in the exhaust gas according to the present embodiment is the same as the mercury treatment system 10 ⁇ / b> A in the exhaust gas according to the first embodiment.
  • a wet desulfurization apparatus 21 is provided for desulfurizing sulfur oxides contained in the exhaust gas 12 after mercury removal.
  • the exhaust gas 12 from which mercury has been removed by the mercury adsorption tower 50 passes through the wet desulfurization device 21, thereby absorbing and removing sulfur oxides present in the gas.
  • the sulfur oxide is less than the predetermined concentration, it may be discharged as it is as the purified gas 24 from the chimney as in the first embodiment, but the sulfur oxide exceeding the environmental standard at the place where the plant is installed is discharged.
  • a desulfurization means such as a wet or dry desulfurization apparatus is provided.
  • the wet desulfurization apparatus 21 a conventional apparatus having an alkali absorbing liquid can be used.
  • the alkali absorbing liquid for example, an aqueous solution of calcium carbonate, calcium hydroxide, sodium hydroxide, sodium sulfite, ammonia, magnesium hydroxide, or the like can be used, but it is not limited thereto.
  • lime gypsum slurry 20 In the wet desulfurization system 21, feeds feeding the flue gas 12 from the wall surface side of the bottom portion 21b of the apparatus main body 21a, lime gypsum slurry 20 to be used as an alkaline absorption liquid in the absorption liquid supply line L 1 by the apparatus body 21a It is supplied and jetted from the nozzle 21c toward the tower top side.
  • the exhaust gas 12 purified by the lime gypsum slurry 20 is discharged from the tower top side, and then discharged from the chimney 25 as the purified gas 24 to the outside of the system.
  • the lime 26 replenished inside the apparatus main body 21a is supplied from a lime supply device 27.
  • the lime gypsum slurry 20 used for the desulfurization of the exhaust gas 12 includes a lime slurry (CaCO 3 ) obtained by dissolving limestone powder in water, and a gypsum slurry (CaSO 4 ) obtained by reacting and further oxidizing lime and SOx in the exhaust gas 12. It is produced by mixing with water.
  • a solution obtained by pumping the liquid stored in the tower bottom 21b of the apparatus main body 21a of the wet desulfurization apparatus 21 with a pump (not shown) is used.
  • SOx in the exhaust gas 12 reacts with lime (CaCO 3 ) in the lime-gypsum slurry 20 as shown in the following formula (4).
  • the lime-gypsum slurry 20 that has absorbed SOx in the exhaust gas 12 is mixed with the water 30 supplied into the apparatus main body 21a, and is oxidized by the air supplied to the tower bottom 21b of the apparatus main body 21a.
  • the lime-gypsum slurry 20 flowing down in the apparatus main body 21a reacts with water 30 and air as shown in the following formula (5).
  • SO x in the exhaust gas 12 is captured in the form of gypsum (CaSO 4 .2H 2 O) in the wet desulfurization apparatus 21.
  • mercury chloride (HgCl 2 ) in the exhaust gas 12 is removed by the mercury adsorption tower 50 provided on the upstream side, it is prevented from being transferred to the lime gypsum slurry 20 side.
  • the lime gypsum slurry 20 used for desulfurization stored in the tower bottom 21b of the wet desulfurization apparatus 21 is oxidized and then extracted from the tower bottom 21b.
  • the extracted lime gypsum slurry 20 is fed to the water separator 33 via the line L 2 and then discharged out of the system as a dehydrated cake (gypsum) 28 containing mercury chloride (HgCl 2 ).
  • the dehydrated filtrate (dehydrated filtrate) 34 is fed to the waste water treatment device 35 via the line L 3 . Then, for example, operations such as removal of suspensions in the dehydrated filtrate, heavy metal 36, and pH adjustment of the dehydrated filtrate are performed by the waste water treatment device 35. A part of the waste water 37 subjected to the waste water treatment is returned to the wet desulfurization apparatus 21, and the other part is treated as the waste water 37.
  • the supply method of the lime gypsum slurry 20 is not limited to the method of jetting from the nozzle 21c toward the tower top side.
  • the lime gypsum slurry 20 may flow down from the nozzle 21c so as to face the exhaust gas 12.
  • the mercury absorption tower 50 is installed before being introduced into the desulfurization apparatus, mercury oxide in the boiler exhaust gas can be efficiently removed, and mercury is contained in the gypsum crystals generated by the desulfurization apparatus. It is possible to prevent mercury from being fixed in gypsum.
  • FIG. 3 is a schematic view of a mercury treatment system in exhaust gas according to Embodiment 3 of the present invention.
  • the mercury treatment system 10C in the exhaust gas according to the present example supplies ammonium chloride instead of the ammonia used in the first example.
  • the reduction oxidation aid is a halogen that generates an oxidation aid and a reduction aid when vaporized. Any compound can be used.
  • the reduction oxidation aid is an oxidation aid used to oxidize metallic mercury (Hg 0 ) in the presence of the oxidation aid, and a reduction agent that reduces NOx with the reduction aid.
  • Hg 0 metallic mercury
  • a reduction agent that reduces NOx with the reduction aid.
  • HCl gas is used as an oxidation aid
  • NH 3 gas is used as a reduction aid.
  • an oxidation aid for example, HCl gas
  • a reduction aid for example, NH 3 gas
  • the exhaust gas 12 discharged from the boiler 11 is supplied with an NH 4 Cl solution 14B from an NH 4 Cl solution supply means 16B via an ammonium chloride (NH 4 Cl) supply line 15B.
  • NH 4 Cl ammonium chloride
  • the droplets of the NH 4 Cl solution 14B sprayed into the flue 13 from the NH 4 Cl solution supply means 16B are evaporated and vaporized by the high-temperature atmosphere temperature of the exhaust gas 12 to generate fine NH 4 Cl solid particles. And decomposed into HCl and NH 3 as shown in the following formula (6). Therefore, the NH 4 Cl solution 14B sprayed from the spraying means is decomposed to generate HCl and NH 3 , and NH 3 gas and HCl gas are supplied into the flue 13.
  • the temperature of the exhaust gas 12 in the flue 13 depends on the combustion conditions of the boiler 11, it is preferably 320 ° C. or higher and 420 ° C. or lower, and more preferably 320 ° C. or higher and 380 ° C. or lower. This is because the NOx denitration reaction and the Hg oxidation reaction can be efficiently generated on the denitration catalyst in this temperature range.
  • the exhaust gas 12 contains HCl gas and NH 3 gas generated from droplets of the NH 4 Cl solution 14B sprayed into the flue 13 from the NH 4 Cl solution supply means 16B, and then is sent to the denitration device 17. Is done.
  • NH 3 gas generated by decomposition of NH 4 Cl is used for NOx reduction denitration
  • HCl gas is used for Hg oxidation
  • NOx and Hg are removed from the exhaust gas 12.
  • the mercury removal rate is improved as compared with the case of using.
  • NH 3 gas reduces and denitrates NOx as shown in the following formula (7) on the denitration catalyst filled in the denitration device 17, and the following formula (8) is obtained using HCl gas.
  • Hg is oxidized. 4NO + 4NH 3 + O 2 ⁇ 4N 2 + 6H 2 O (7) Hg + 1 / 2O 2 + 2HCl ⁇ HgCl 2 + H 2 O (8)
  • the exhaust gas 12 is subjected to NOx reduction and Hg oxidation in the exhaust gas 12 in the denitration device 17, and then the temperature of the exhaust gas 12 is lowered by the air heater 18.
  • the exhaust gas 12 is introduced into the mercury absorption tower 50, where mercury oxide is absorbed and removed by the mercury absorption liquid 51, and then sent to the wet desulfurization device 21 for desulfurization treatment.
  • mercury is oxidized in the exhaust gas by the denitration device 17, and this oxidized mercury is reliably treated with the mercury absorbing solution 51 in the mercury absorption tower 50, so that mercury is reliably removed. Will be able to.
  • FIG. 4 is a schematic diagram of a mercury treatment system in exhaust gas according to Embodiment 4 of the present invention.
  • the mercury treatment system 10 ⁇ / b> D in the exhaust gas according to the present embodiment is provided with an aggregating device 71 that agglomerates the agglomerates in the mercury absorption liquid collected in the collection tank 52.
  • an aggregating agent 72 such as an aggregating agent such as a heavy metal scavenger and a chelating agent is charged to agglomerate the agglomerates containing mercury in the mercury absorbing solution 51.
  • Examples of the aggregating agent 72 include an Fe-based aggregating agent, an Al-based aggregating agent, and a polymer-based aggregating agent.
  • the mercury oxide in the mercury absorbing solution 51 is agglomerated and solidified to be transferred from the liquid phase to the solid phase.
  • the agglomerate 73 in the aggregating device 71 is subjected to a separate evaporating process by an evaporating process means so as to perform no drainage.
  • FIG. 5 is a schematic diagram of a mercury treatment system in exhaust gas according to Embodiment 5 of the present invention.
  • the mercury treatment system 10E in the exhaust gas according to the present embodiment is provided with a dehydration processing device 74 that dehydrates the agglomerates 73 from the aggregation device 71 of the fourth embodiment and separates them into solid and liquid. .
  • the dewatered sludge 75 contains mercury, it is processed separately. Further, the treated water 76 which is a filtrate is reused as a part of the mercury absorbing solution 51.
  • the reuse may be treated together with the drainage treatment for evaporating and the wastewater 37 of the wastewater treatment device 35.

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

Abstract

Cette invention concerne un système pour traiter le mercure dans un gaz d'échappement, le système éliminant le mercure contenu dans le gaz d'échappement (12) provenant d'une chaudière (11) et comprenant : un dispositif de dénitration (17) qui élimine les oxydes d'azote (NOx) présents dans le gaz d'échappement (12) provenant de la chaudière (11), la combustion dans la chaudière s'opérant par apport d'un combustible (F) ; un réchauffeur d'air (AH) (18) qui se trouve en aval du dispositif de dénitration (17) et qui ajuste la température du gaz d'échappement ; un collecteur de poussières (19) qui se trouve en aval du réchauffeur d'air (18) et qui élimine les matières particulaires présentes dans le gaz d'échappement ; et une colonne d'absorption de mercure (50) qui se trouve en aval du collecteur de poussières (19) et qui élimine l'oxyde de mercure (Hg2+) présent dans le gaz d'échappement (12) à l'aide d'un liquide d'absorption de mercure (51).
PCT/JP2013/071886 2012-09-14 2013-08-13 Système de traitement du mercure contenu dans un gaz d'échappement WO2014041951A1 (fr)

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JP2012203442A JP2014057912A (ja) 2012-09-14 2012-09-14 排ガス中の水銀処理システム
JP2012-203442 2012-09-14

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CN106076107A (zh) * 2016-08-04 2016-11-09 西安热工研究院有限公司 一种烟气中Hg2+的脱除系统与方法
JP2020014975A (ja) * 2018-07-23 2020-01-30 三菱日立パワーシステムズ株式会社 酸化還元電位決定装置及びそれを備える脱硫装置、並びに酸化還元電位決定方法

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JP6637682B2 (ja) * 2015-06-18 2020-01-29 三菱日立パワーシステムズ株式会社 石炭焚ボイラ用排ガス処理装置と石炭焚ボイラ用排ガス処理方法
CN105617858B (zh) * 2016-01-15 2018-10-30 环境保护部华南环境科学研究所 一种组合式烟气多污染物协同深度净化工艺
CN106178913A (zh) * 2016-08-04 2016-12-07 中国神华能源股份有限公司 一种烟气净化系统及方法

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JP2004313833A (ja) * 2003-04-11 2004-11-11 Mitsubishi Heavy Ind Ltd 排ガス中の水銀除去方法およびそのシステム
JP2007007580A (ja) * 2005-06-30 2007-01-18 Mitsubishi Heavy Ind Ltd 排ガス処理装置及び方法
JP2010269277A (ja) * 2009-05-25 2010-12-02 Babcock Hitachi Kk 脱硫装置における水銀再放出抑制方法および装置
WO2011104840A1 (fr) * 2010-02-25 2011-09-01 三菱重工業株式会社 Système de traitement de gaz d'échappement, et procédé de traitement de gaz d'échappement

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JP2004313833A (ja) * 2003-04-11 2004-11-11 Mitsubishi Heavy Ind Ltd 排ガス中の水銀除去方法およびそのシステム
JP2007007580A (ja) * 2005-06-30 2007-01-18 Mitsubishi Heavy Ind Ltd 排ガス処理装置及び方法
JP2010269277A (ja) * 2009-05-25 2010-12-02 Babcock Hitachi Kk 脱硫装置における水銀再放出抑制方法および装置
WO2011104840A1 (fr) * 2010-02-25 2011-09-01 三菱重工業株式会社 Système de traitement de gaz d'échappement, et procédé de traitement de gaz d'échappement

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106076107A (zh) * 2016-08-04 2016-11-09 西安热工研究院有限公司 一种烟气中Hg2+的脱除系统与方法
CN106076107B (zh) * 2016-08-04 2018-08-07 西安热工研究院有限公司 一种烟气中Hg2+的脱除系统与方法
JP2020014975A (ja) * 2018-07-23 2020-01-30 三菱日立パワーシステムズ株式会社 酸化還元電位決定装置及びそれを備える脱硫装置、並びに酸化還元電位決定方法
JP7164344B2 (ja) 2018-07-23 2022-11-01 三菱重工業株式会社 酸化還元電位決定装置及びそれを備える脱硫装置、並びに酸化還元電位決定方法

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