WO2012026114A1 - Exhaust gas processing device - Google Patents

Exhaust gas processing device Download PDF

Info

Publication number
WO2012026114A1
WO2012026114A1 PCT/JP2011/004686 JP2011004686W WO2012026114A1 WO 2012026114 A1 WO2012026114 A1 WO 2012026114A1 JP 2011004686 W JP2011004686 W JP 2011004686W WO 2012026114 A1 WO2012026114 A1 WO 2012026114A1
Authority
WO
WIPO (PCT)
Prior art keywords
exhaust gas
sulfur trioxide
mercury
treatment apparatus
sulfur
Prior art date
Application number
PCT/JP2011/004686
Other languages
French (fr)
Japanese (ja)
Inventor
森本　信夫
尾田　直己
中本　隆則
浩之 野坂
小林　和樹
Original Assignee
バブコック日立株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by バブコック日立株式会社 filed Critical バブコック日立株式会社
Publication of WO2012026114A1 publication Critical patent/WO2012026114A1/en

Links

Images

Classifications

    • 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
    • B01D53/46—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
    • B01D53/74—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
    • 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
    • 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
    • B01D2251/30—Alkali metal compounds
    • B01D2251/304—Alkali metal compounds of sodium
    • 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
    • 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
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases
    • 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

Definitions

  • the present invention relates to an exhaust gas treatment apparatus, and more particularly to a technology for purifying combustion exhaust gas of carbon-containing solid fuel such as coal.
  • Patent Document 1 nitrogen oxides in exhaust gas burned with coal are removed with a denitration device, soot in the exhaust gas discharged from the denitration device is removed with a dust collector, and discharged from the dust collector.
  • An exhaust gas treatment device for removing sulfur oxides in exhaust gas with a wet desulfurization device has been proposed.
  • mercury contained in the exhaust gas adheres to the dust and is removed by the dust collector, and mercury that has not been removed by the dust collector is absorbed and removed by the absorbent of the wet desulfurizer. It is supposed to.
  • Patent Document 1 the dust cannot be recycled or landfilled unless the mercury adhering to the dust collected by the dust collector is removed or solidified so as not to elute. Therefore, there is a problem that a device for treating a large amount of dust must be separately provided in order to prevent the elution of a small amount of mercury adhering to the dust.
  • the problem to be solved by the present invention is to inhibit mercury from adhering to the dust collected by the dust collector.
  • the inventors of the present invention have intensively studied to inhibit mercury from adhering to the dust, and as a result, the rate at which sulfur trioxide adheres to the dust is faster than the rate at which mercury adheres to the dust. I found out. In other words, in an atmosphere where mercury and sulfur trioxide coexist, we found that sulfur trioxide adhered to the dust before mercury, and the adhering sulfur trioxide hindered the adhesion of mercury to the dust.
  • the exhaust gas treatment apparatus of the present invention introduces exhaust gas containing mercury obtained by burning carbon-containing solid fuel, and oxidizes mercury in the exhaust gas into divalent mercury.
  • a mercury oxidation catalyst device, an injection device for injecting sulfur trioxide into a flue through which exhaust gas discharged from the mercury oxidation catalyst device flows, and a dust collector for collecting soot dust in the exhaust gas that has passed through the injection device It is characterized by providing.
  • sulfur trioxide stored in the cylinder can be injected into the flue upstream of the dust collector.
  • the combustion exhaust gas of carbon-containing solid fuel often contains sulfur dioxide
  • the exhaust gas containing sulfur dioxide is branched, and the sulfur dioxide in the exhaust gas is oxidized in the presence of a sulfur oxidation catalyst to trioxide.
  • the exhaust gas converted to sulfur and having a higher sulfur trioxide concentration can be returned to the inlet side of the dust collector via the bypass pipe. According to this, since the sulfur trioxide concentration of exhaust gas can be increased using sulfur dioxide in the exhaust gas, a facility for storing sulfur trioxide can be eliminated.
  • the exhaust gas can be branched upstream of the dust collector through which high-temperature exhaust gas, for example, 350 ° C. to 400 ° C. exhaust gas flows. That is, since the reaction for converting sulfur dioxide into sulfur trioxide is promoted at 350 ° C. or higher, it is preferable to branch the exhaust gas at or above this temperature and pass it through the sulfur oxidation catalyst device.
  • high-temperature exhaust gas for example, 350 ° C. to 400 ° C. exhaust gas flows. That is, since the reaction for converting sulfur dioxide into sulfur trioxide is promoted at 350 ° C. or higher, it is preferable to branch the exhaust gas at or above this temperature and pass it through the sulfur oxidation catalyst device.
  • the sulfur oxidation catalyst may be deteriorated by the dust in the exhaust gas. Therefore, the deterioration of the sulfur oxidation catalyst can be suppressed by branching the exhaust gas downstream of the dust collector from which the dust is removed.
  • the branched exhaust gas is heated to 350 ° C. or higher with a heater and passed through the sulfur oxidation catalyst device.
  • the adhesion of mercury to the dust can be made almost zero by setting the sulfur trioxide concentration on the dust collector inlet side to 20 ppm or more. Therefore, it is preferable to inject sulfur trioxide so that the sulfur trioxide concentration on the dust collector inlet side is maintained at 20 ppm or more.
  • a mercury oxidation catalyst device also facilitates the reaction of converting sulfur dioxide to sulfur trioxide. Therefore, the sulfur trioxide concentration in the exhaust gas is obtained from the difference in the sulfur dioxide concentration between the inlet side and the outlet side of the mercury oxidation catalyst device, and the injection amount of sulfur trioxide is adjusted based on the obtained sulfur trioxide concentration to collect dust.
  • the sulfur trioxide concentration on the apparatus inlet side can be controlled to a set concentration, for example, 20 ppm or more. Since the acid dew point increases as the sulfur trioxide concentration in the exhaust gas increases, the set concentration of sulfur trioxide can be set to 20 ppm or more, preferably in the range of 25 ppm to 30 ppm.
  • the mercury in the exhaust gas is oxidized into water-soluble divalent mercury by the mercury oxidation catalyst device, so a wet desulfurization device is installed downstream of the dust collector, and mercury is removed together with the sulfur oxide in the exhaust gas. It can be removed by absorption in an absorbing solution.
  • a removing device that removes mercury by spreading an absorbing solution that absorbs mercury on exhaust gas can be installed on the inlet side of the wet desulfurization device.
  • an addition device for adding the mercury adsorbent to the exhaust gas and a removal device for removing the adsorbent adsorbed with mercury from the exhaust gas can be installed on the inlet side of the wet desulfurization device. Since the amount of mercury in the exhaust gas is very small, it can be removed with a small amount of absorption liquid or adsorbent, so that the absorption liquid or adsorbent after use can be treated with simple equipment compared to equipment that treats soot and dust.
  • sulfur trioxide is difficult to remove with a wet desulfurization apparatus, if the sulfur trioxide concentration in the exhaust gas is increased, there is a possibility that sulfur trioxide cannot be completely removed with the wet desulfurization apparatus.
  • a reducing agent that reduces sulfur trioxide can be added on the inlet side of the wet desulfurization apparatus, and the sulfur trioxide can be converted into sulfur dioxide that can be easily removed by the wet desulfurization apparatus.
  • a wet dust collector capable of removing sulfur trioxide is disposed on the outlet side of the wet desulfurization device, and sulfur trioxide that has passed through the wet desulfurization device can be removed from the exhaust gas.
  • Embodiment 1 is a block diagram of an exhaust gas treatment apparatus according to Embodiment 1 of the present invention. It is a figure which shows the relationship between the sulfur trioxide density
  • Embodiment 1 As shown in FIG. 1, the exhaust gas treatment apparatus of Embodiment 1 is installed in a thermal power plant or the like, and the exhaust gas discharged from a coal-fired boiler 1 that burns carbon-containing solid fuel, for example, coal, is a mercury oxidation catalyst apparatus. 3 is introduced.
  • the mercury oxidation catalyst device 3 is provided with a well-known catalyst layer that promotes a reaction of oxidizing metal mercury in exhaust gas to divalent mercury.
  • the exhaust gas discharged from the mercury oxidation catalyst device 3 is introduced into the air preheater 5.
  • the air preheater 5 heats the combustion air of the boiler 1 with exhaust gas, for example.
  • the exhaust gas discharged from the air preheater 5 is introduced into the dry dust collector 7.
  • the dust collector 7 collects the dust in the exhaust gas and removes it from the exhaust gas.
  • the exhaust gas discharged from the dust collector 7 is introduced into a wet dust collector 9 described later and mercury is removed, and then introduced into the wet desulfurizer 11.
  • the wet desulfurization apparatus 11 spreads a calcium-based absorption liquid on exhaust gas, absorbs sulfur oxide in the exhaust gas, converts it into gypsum, and removes it from the exhaust gas.
  • the exhaust gas discharged from the wet desulfurization apparatus 11 is heated by, for example, a reheater (not shown) and is discharged from the chimney 13 into the atmosphere.
  • the flue on the inlet side of the dust collector 7 is provided with an injection device 15 for injecting sulfur trioxide into the flue.
  • the injection device 15 includes a cylinder (not shown) in which sulfur trioxide is stored, and the sulfur trioxide concentration in the exhaust gas based on the sulfur dioxide concentration on the inlet side of the mercury oxidation catalyst device 3 and on the outlet side of the air preheater 5.
  • a control device (not shown) that controls the sulfur trioxide concentration in the exhaust gas introduced into the dust collector 7 to a set concentration by adjusting the injection amount of sulfur trioxide based on the obtained sulfur trioxide concentration Is provided.
  • a detector 17 for detecting the concentration of sulfur dioxide is connected to the control device, and exhaust gas is introduced into the detector 17 through sample pipes 19 and 20.
  • the flue on the inlet side of the wet desulfurization apparatus 11 is provided with an addition apparatus 21 for adding a basic substance containing a sulfur trioxide reducing agent, such as a sodium component, to the exhaust gas.
  • the adding device 21 adds a known reducing agent that reduces sulfur trioxide to sulfur dioxide to the exhaust gas.
  • a wet dust collecting device 9 for spraying an absorbing liquid that absorbs mercury to the exhaust gas is provided.
  • the wet dust collector 9 spreads a well-known absorption liquid that absorbs mercury on exhaust gas, and discharges the absorption liquid that has absorbed mercury.
  • the operation of the exhaust gas treatment apparatus of the first embodiment configured as described above will be described.
  • Metallic mercury in the exhaust gas discharged from the boiler 1 is converted into divalent mercury that is easily dissolved in water by the mercury oxidation catalyst device 3.
  • the exhaust gas that has passed through the mercury oxidation catalyst device 3 is reduced in temperature to, for example, about 150 ° C. to 200 ° C. by heat exchange with the combustion air of the boiler 1 in the air preheater 5.
  • the temperature-reduced exhaust gas is introduced into the dust collector 7, and the dust in the exhaust gas is removed by the dust collector 7.
  • the exhaust gas from which the dust has been removed passes through the wet dust collector 9 and the wet desulfurizer 11 removes sulfur oxides such as sulfur dioxide and sulfur trioxide in the exhaust gas.
  • the exhaust gas discharged from the air preheater 5 is supplied with sulfur trioxide from the injection device 15.
  • the control device for controlling the sulfur trioxide concentration in the exhaust gas to the set concentration is based on the difference in sulfur dioxide concentration between the inlet side of the mercury oxidation catalyst device 3 and the outlet side of the air preheater 5 detected by the detector 17.
  • the concentration of sulfur dioxide converted to sulfur trioxide by the mercury oxidation catalyst device 3 is obtained, and the concentration of sulfur trioxide in the exhaust gas is estimated.
  • the sulfur trioxide concentration in the exhaust gas is maintained at the set concentration. Adjust the supply amount of sulfur trioxide in the cylinder.
  • the set concentration is a concentration at which sulfur trioxide adheres to the dust before the bivalent mercury and can inhibit the adhesion of the bivalent mercury to the dust. For example, as shown in the graph of FIG. 2, as the sulfur trioxide concentration on the inlet side of the dust collector 7 increases, the mercury removal rate in the dust collector 7 due to mercury adhering to the dust decreases.
  • the set concentration of sulfur trioxide is set to 20 ppm or more, preferably 25 ppm to 30 ppm.
  • sulfur trioxide (SO 3 ) adheres to the dust (Ash) before the divalent mercury (Hg 2+ ), and the adsorbed mercury to the dust by the adsorbed sulfur trioxide. Be inhibited.
  • a reducing agent that reduces sulfur trioxide to sulfur dioxide is added from the addition device 21 to the exhaust gas discharged from the dust collector 7.
  • sulfur trioxide which is difficult to remove with the wet desulfurization apparatus 11 is reduced to sulfur dioxide which is easy to remove with the wet desulfurization apparatus.
  • the exhaust gas that has passed through the adding device 21 is introduced into the wet dust collector 9, and an absorbing liquid that absorbs mercury is dispersed, and the mercury in the exhaust gas is absorbed into the absorbing liquid and removed from the exhaust gas.
  • the adhesion of mercury to the dust can be inhibited by the sulfur trioxide injected to the upstream side of the dust collector 7. Therefore, the dust can be recycled, for example, as a cement material without performing treatment for preventing the elution of mercury adhering to the dust. In addition, soil contamination by mercury does not occur even if the dust is landfilled. In addition, although the sulfur trioxide has adhered to the dust collected with the dust collector 7, sulfur trioxide can be easily detoxified by the neutralization process.
  • the sulfur trioxide is reduced to sulfur dioxide by the reducing agent that reduces sulfur trioxide, the sulfur trioxide injected to inhibit the adhesion of mercury to the dust can be removed by the wet desulfurization apparatus 11.
  • mercury is removed upstream of the wet desulfurization apparatus 11 and the exhaust gas from which mercury has been removed is introduced into the wet desulfurization apparatus 11, mercury is mixed into the desulfurization product of the wet desulfurization apparatus 11, for example, gypsum. And can be used for building materials.
  • a known denitration device is installed instead of the mercury oxidation catalyst device 3 to add a denitration agent to reduce nitrogen oxides in the exhaust gas in the presence of the catalyst. can do. That is, the metal mercury in the exhaust gas can be oxidized to divalent mercury by the catalyst used in the denitration apparatus.
  • the detector for detecting sulfur trioxide can directly detect the sulfur trioxide concentration on the inlet side of the dust collector 7, but if it is difficult to detect the sulfur trioxide concentration immediately, As in Embodiment 1, it is preferable to obtain sulfur trioxide in the exhaust gas from the oxidation rate of sulfur dioxide in the mercury oxidation catalyst device 3.
  • the detector 17 is omitted and the sulfur trioxide in the exhaust gas based on the predicted concentration.
  • the injection amount of sulfur trioxide can be adjusted so as to maintain the concentration at the set concentration.
  • the addition apparatus 21 for adding a reducing agent that reduces sulfur trioxide to sulfur dioxide can be omitted.
  • the addition apparatus 21 is abbreviate
  • the wet dust collector 9 for removing mercury in the exhaust gas can be omitted, and the mercury in the exhaust gas can be absorbed by the absorption liquid of the wet desulfurization device 11 and removed from the exhaust gas.
  • mercury is mixed in the desulfurization product, but since the wet desulfurization apparatus 11 also serves as the mercury removal apparatus, the exhaust gas treatment apparatus can be simplified.
  • FIG. 4 shows a block diagram of the exhaust gas treatment apparatus of the second embodiment.
  • the difference between the second embodiment and the first embodiment is that, instead of the wet dust collector 9, an addition device 25 that adds a mercury adsorbent to the exhaust gas, and a removal that removes the adsorbent from the exhaust gas that has passed through the addition device 25.
  • the apparatus 27 is arranged on the inlet side of the wet desulfurization apparatus 11. Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.
  • a mercury adsorbent for example, activated carbon
  • activated carbon is added to the exhaust gas that has passed through the dust collector 7 from the adding device 25.
  • mercury in the exhaust gas is adsorbed to the activated carbon because it is oxidized by the mercury oxidation catalyst device 3 to divalent mercury having a low vapor pressure.
  • the activated carbon on which mercury is adsorbed is collected by a removing device 27, for example, a bag filter, and removed from the exhaust gas. Thereby, mercury is removed from the exhaust gas.
  • Activated carbon collected and recovered by the bag filter is introduced into a regenerator (not shown), and mercury is desorbed from the activated carbon by controlling temperature and pressure.
  • the activated carbon from which mercury has been desorbed is returned to the adding device and added again into the exhaust gas. Thereby, activated carbon can be recycled.
  • mercury can be prevented from being mixed with the gypsum obtained by the wet desulfurization apparatus 11, and high-purity gypsum can be obtained. Further, since the amount of mercury in the exhaust gas is very small, mercury can be removed with a small amount of adsorbent, so that the adsorbent with mercury attached can be easily treated.
  • the adsorbed sulfur trioxide may inhibit mercury adsorption on the activated carbon. Therefore, it is preferable to add a reducing agent of sulfur trioxide to the upstream side of the adding device 25 and reduce the sulfur trioxide to sulfur dioxide and then add the activated carbon.
  • the adsorbent addition position is downstream of the dust collector 7 because it is difficult to regenerate the adsorbent because the dust and adsorbent cannot be separated.
  • the side is preferred.
  • FIG. 5 shows a block diagram of the exhaust gas treatment apparatus of the third embodiment.
  • the difference between the third embodiment and the first embodiment is that, instead of the mercury oxidation catalyst device 3, a denitration device 31 is installed to remove nitrogen oxides in the exhaust gas in the presence of the catalyst by adding a denitration agent. It is. Then, the exhaust gas is branched at the inlet side of the air preheater 5, the sulfur oxidation catalyst device 33 that oxidizes sulfur dioxide in the exhaust gas to sulfur trioxide, and the exhaust gas discharged from the sulfur oxidation catalyst device 33 of the dust collector 7.
  • a sulfur trioxide injection device 37 is formed by the bypass pipe 35 returned to the inlet side. Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.
  • the exhaust gas discharged from the boiler 1 is introduced into the denitration device 31.
  • the denitration device 31 adds a denitration agent such as ammonia to the exhaust gas, and reduces nitrogen oxides in the exhaust gas to nitrogen in the presence of the denitration catalyst to remove it from the exhaust gas.
  • metallic mercury in the exhaust gas is oxidized to divalent mercury by the denitration catalyst.
  • High-temperature exhaust gas that has passed through the denitration device 31, for example, 350 ° C. to 400 ° C. exhaust gas, is branched by the fan 39 of the bypass pipe 35.
  • the branched exhaust gas is introduced into the sulfur oxidation catalyst device 33, and sulfur dioxide in the exhaust gas is oxidized to sulfur trioxide.
  • the exhaust gas that has passed through the sulfur oxidation catalyst device 33 is returned to the flue on the inlet side of the dust collector 7 via the bypass pipe 35. Thereby, sulfur trioxide can be injected into the inlet side of the dust collector 7.
  • the injection device 37 is provided with a valve 41 that adjusts the branching amount of the exhaust gas and an adjustment device 43 that adjusts the opening degree of the valve 41.
  • the valve 41 is provided in the middle of the flow path of the bypass pipe 35, and can adjust the flow rate of the exhaust gas branched into the bypass pipe 35 by adjusting the opening degree of the valve 41.
  • the adjustment device 43 receives the detection value of the flow rate detector 45 provided in the bypass pipe 35 and the detection values of the sulfur dioxide concentration on the inlet side and the outlet side of the sulfur oxidation catalyst device 33 detected by the detector 17. It has come to be. Then, the adjustment device 43 obtains the amount of sulfur trioxide generated by the sulfur oxidation catalyst device 33 from the difference between the detected values of the sulfur dioxide concentration detected by the detector 17 and the exhaust gas flow rate detected by the flow rate detector 45. It is like that.
  • emitted from the boiler 1 is input into the regulator 43 so that the sulfur trioxide density
  • the adjusting device 43 estimates the sulfur trioxide concentration in the exhaust gas introduced into the dust collector 7, and adjusts the opening of the valve 41 so as to maintain this estimated concentration at a set value. Adjust the amount of branching to adjust the amount of sulfur trioxide produced.
  • the sulfur trioxide concentration of the exhaust gas can be increased by using sulfur dioxide in the exhaust gas, a facility for storing sulfur trioxide can be eliminated. Further, since the work of replenishing sulfur trioxide from the outside can be made unnecessary, the work accompanying the injection of sulfur trioxide can be reduced.
  • the flow rate 47 of the exhaust gas discharged from the boiler 1 is obtained by using a measurement signal of the combustion air amount of the boiler 1 or a measurement signal of a gas flow meter provided on the inlet side of the wet desulfurization apparatus 11. Can do. Further, a gas flow meter can be installed on the inlet side of the dust collector 7 and obtained using a measurement signal of the flow rate measurement value.
  • FIG. 6 shows a block diagram of an exhaust gas treatment apparatus according to the fourth embodiment which is a modification of the third embodiment.
  • the fourth embodiment differs from the third embodiment in that the position where the exhaust gas is branched is changed to the outlet side of the dust collector 7 instead of the inlet side of the air preheater 5.
  • the heater 49 for heating the branched exhaust gas is disposed on the inlet side of the sulfur oxidation catalyst device 33. Since other configurations are the same as those of the third embodiment, the same reference numerals are given and description thereof is omitted.
  • the catalyst in the sulfur oxidation catalyst device 33 may be deteriorated by dust in the exhaust gas. Therefore, in the exhaust gas treatment apparatus of Embodiment 4, the exhaust gas from which the dust is removed by the dust collector 7 is branched and introduced into the sulfur oxidation catalyst device 33. Thereby, it can prevent that the catalyst in the sulfur oxidation catalyst apparatus 33 deteriorates by dust.
  • the exhaust gas at the outlet side of the dust collector 7 is reduced in temperature by the air preheater 5.
  • a heater 49 on the inlet side of the sulfur oxidation catalyst device 33 and to heat the branched exhaust gas to a temperature at which the reaction of oxidizing sulfur dioxide to sulfur trioxide is promoted, for example, 350 ° C. or more. .

Abstract

This exhaust gas processing device is provided with: a mercury oxidation catalyst device to which mercury-containing exhaust gas from the combustion of a carbon-containing solid fuel is introduced, and that oxidizes the mercury in the exhaust gas to divalent mercury; an injection device that injects sulfur trioxide into the flue through which the exhaust gas released from the mercury oxidation catalyst device flows; and a dust collection device that collects dust in the exhaust gas that has passed through the injection device. The injected sulfur trioxide is adsorbed by the dust, and inhibits mercury from being adsorbed by the dust collected by the dust collection device.

Description

排ガス処理装置Exhaust gas treatment equipment
　本発明は、排ガス処理装置に係り、特に、石炭等の炭素含有固体燃料の燃焼排ガスを浄化する技術に関する。 The present invention relates to an exhaust gas treatment apparatus, and more particularly to a technology for purifying combustion exhaust gas of carbon-containing solid fuel such as coal.
　例えば、特許文献１には、石炭を燃焼した排ガス中の窒素酸化物を脱硝装置で除去し、脱硝装置から排出された排ガス中の煤塵を集塵装置で除去し、集塵装置から排出された排ガス中の硫黄酸化物を湿式脱硫装置で除去する排ガス処理装置が提案されている。特に、同文献によれば、排ガスに含まれる水銀は煤塵に付着して集塵装置で除去されるとともに、集塵装置で除去されなかった水銀は湿式脱硫装置の吸収液に吸収されて除去されるとしている。 For example, in Patent Document 1, nitrogen oxides in exhaust gas burned with coal are removed with a denitration device, soot in the exhaust gas discharged from the denitration device is removed with a dust collector, and discharged from the dust collector. An exhaust gas treatment device for removing sulfur oxides in exhaust gas with a wet desulfurization device has been proposed. In particular, according to this document, mercury contained in the exhaust gas adheres to the dust and is removed by the dust collector, and mercury that has not been removed by the dust collector is absorbed and removed by the absorbent of the wet desulfurizer. It is supposed to.
ＷＯ２００４／０２３０４０号公報WO2004 / 023040
　しかしながら、特許文献１は、集塵装置で捕集した煤塵に付着した水銀を除去あるいは、溶出しないように固溶化しなければ、煤塵をリサイクルや埋め立て処理できない。したがって、煤塵に付着した微量の水銀の溶出防止のために、多量の煤塵を処理する装置を別途設けなければならないという問題がある。 However, in Patent Document 1, the dust cannot be recycled or landfilled unless the mercury adhering to the dust collected by the dust collector is removed or solidified so as not to elute. Therefore, there is a problem that a device for treating a large amount of dust must be separately provided in order to prevent the elution of a small amount of mercury adhering to the dust.
　本発明が解決しようとする課題は、集塵装置で捕集される煤塵に水銀が付着することを阻害することにある。 The problem to be solved by the present invention is to inhibit mercury from adhering to the dust collected by the dust collector.
　本発明の発明者らは、煤塵に水銀が付着することを阻害するために鋭意研究した結果、水銀が煤塵に付着する速度よりも、三酸化硫黄が煤塵に付着する速度の方が速いことを知見した。つまり、水銀と三酸化硫黄が共存する雰囲気下では、水銀よりも先に煤塵に三酸化硫黄が付着し、付着した三酸化硫黄により煤塵への水銀の付着が阻害されることを見いだした。 The inventors of the present invention have intensively studied to inhibit mercury from adhering to the dust, and as a result, the rate at which sulfur trioxide adheres to the dust is faster than the rate at which mercury adheres to the dust. I found out. In other words, in an atmosphere where mercury and sulfur trioxide coexist, we found that sulfur trioxide adhered to the dust before mercury, and the adhering sulfur trioxide hindered the adhesion of mercury to the dust.
　これらの知見に基づいて、上記課題を解決するため、本発明の排ガス処理装置は、炭素含有固体燃料を燃焼させた水銀を含む排ガスが導入され、排ガス中の水銀を２価の水銀に酸化する水銀酸化触媒装置と、水銀酸化触媒装置から排出される排ガスが通流する煙道内に三酸化硫黄を注入する注入装置と、注入装置を通過した排ガス中の煤塵を捕集する集塵装置とを備えることを特徴とする。 Based on these findings, in order to solve the above problems, the exhaust gas treatment apparatus of the present invention introduces exhaust gas containing mercury obtained by burning carbon-containing solid fuel, and oxidizes mercury in the exhaust gas into divalent mercury. A mercury oxidation catalyst device, an injection device for injecting sulfur trioxide into a flue through which exhaust gas discharged from the mercury oxidation catalyst device flows, and a dust collector for collecting soot dust in the exhaust gas that has passed through the injection device It is characterized by providing.
　これによれば、集塵装置の上流側に三酸化硫黄を注入することで、水銀よりも先に煤塵に三酸化硫黄が付着し、付着した三酸化硫黄により煤塵への水銀の付着が阻害される。したがって、煤塵に付着した水銀の溶出防止のための装置を別途設ける必要がない。 According to this, by injecting sulfur trioxide upstream of the dust collector, sulfur trioxide adheres to the dust before the mercury, and the adhering sulfur trioxide inhibits mercury from adhering to the dust. The Therefore, it is not necessary to separately provide a device for preventing elution of mercury adhering to dust.
　この場合において、ボンベに貯蔵された三酸化硫黄を集塵装置の上流側の煙道内に注入することができる。 In this case, sulfur trioxide stored in the cylinder can be injected into the flue upstream of the dust collector.
　また、炭素含有固体燃料の燃焼排ガスには、二酸化硫黄が含まれることが多いので、この二酸化硫黄を含む排ガスを分岐して、排ガス中の二酸化硫黄を硫黄酸化触媒存在下で酸化して三酸化硫黄に転換し、三酸化硫黄濃度を高めた排ガスをバイパス管を介して集塵装置の入口側に戻すことができる。これによれば、排ガス中の二酸化硫黄を利用して排ガスの三酸化硫黄濃度を増加できるので、三酸化硫黄を貯蔵する設備を不要にできる。 In addition, since the combustion exhaust gas of carbon-containing solid fuel often contains sulfur dioxide, the exhaust gas containing sulfur dioxide is branched, and the sulfur dioxide in the exhaust gas is oxidized in the presence of a sulfur oxidation catalyst to trioxide. The exhaust gas converted to sulfur and having a higher sulfur trioxide concentration can be returned to the inlet side of the dust collector via the bypass pipe. According to this, since the sulfur trioxide concentration of exhaust gas can be increased using sulfur dioxide in the exhaust gas, a facility for storing sulfur trioxide can be eliminated.
　この場合において、高温の排ガス、例えば、３５０℃～４００℃の排ガスが通流する集塵装置の上流側で排ガスを分岐することができる。つまり、二酸化硫黄を三酸化硫黄に転換する反応は３５０℃以上で促進されるから、この温度以上の排ガスを分岐して硫黄酸化触媒装置に通流させることが好ましい。 In this case, the exhaust gas can be branched upstream of the dust collector through which high-temperature exhaust gas, for example, 350 ° C. to 400 ° C. exhaust gas flows. That is, since the reaction for converting sulfur dioxide into sulfur trioxide is promoted at 350 ° C. or higher, it is preferable to branch the exhaust gas at or above this temperature and pass it through the sulfur oxidation catalyst device.
　一方、集塵装置の上流側で分岐した排ガスを硫黄酸化触媒装置に通流させると、排ガス中の煤塵により硫黄酸化触媒が劣化するおそれがある。そのため、煤塵が除去された集塵装置の下流側の排ガスを分岐することで、硫黄酸化触媒の劣化を抑制できる。なお、集塵装置の下流側の排ガスは温度が低いので、分岐した排ガスを加熱器で３５０℃以上に加熱し、硫黄酸化触媒装置に通流させることが好ましい。 On the other hand, if the exhaust gas branched upstream of the dust collector is passed through the sulfur oxidation catalyst device, the sulfur oxidation catalyst may be deteriorated by the dust in the exhaust gas. Therefore, the deterioration of the sulfur oxidation catalyst can be suppressed by branching the exhaust gas downstream of the dust collector from which the dust is removed. In addition, since the temperature of the exhaust gas downstream of the dust collector is low, it is preferable that the branched exhaust gas is heated to 350 ° C. or higher with a heater and passed through the sulfur oxidation catalyst device.
　また、本発明の発明者らの知見によれば、集塵装置入口側の三酸化硫黄濃度を２０ｐｐｍ以上にすることで、煤塵への水銀の付着をほぼゼロにできる。そのため、集塵装置入口側の三酸化硫黄濃度を２０ｐｐｍ以上に維持するように、三酸化硫黄を注入することが好ましい。例えば、水銀酸化触媒装置は二酸化硫黄を三酸化硫黄に転換する反応も促進する。そこで、水銀酸化触媒装置の入口側と出口側の二酸化硫黄濃度の差分から排ガス中の三酸化硫黄濃度を求め、求めた三酸化硫黄濃度に基づいて三酸化硫黄の注入量を調整し、集塵装置入口側の三酸化硫黄濃度を設定濃度、例えば、２０ｐｐｍ以上に制御することができる。なお、排ガス中の三酸化硫黄濃度が高くなると酸露点が上昇するので、三酸化硫黄の設定濃度は、２０ｐｐｍ以上、好ましくは、２５ｐｐｍ～３０ｐｐｍの範囲にすることができる。 Further, according to the knowledge of the inventors of the present invention, the adhesion of mercury to the dust can be made almost zero by setting the sulfur trioxide concentration on the dust collector inlet side to 20 ppm or more. Therefore, it is preferable to inject sulfur trioxide so that the sulfur trioxide concentration on the dust collector inlet side is maintained at 20 ppm or more. For example, a mercury oxidation catalyst device also facilitates the reaction of converting sulfur dioxide to sulfur trioxide. Therefore, the sulfur trioxide concentration in the exhaust gas is obtained from the difference in the sulfur dioxide concentration between the inlet side and the outlet side of the mercury oxidation catalyst device, and the injection amount of sulfur trioxide is adjusted based on the obtained sulfur trioxide concentration to collect dust. The sulfur trioxide concentration on the apparatus inlet side can be controlled to a set concentration, for example, 20 ppm or more. Since the acid dew point increases as the sulfur trioxide concentration in the exhaust gas increases, the set concentration of sulfur trioxide can be set to 20 ppm or more, preferably in the range of 25 ppm to 30 ppm.
　ところで、排ガス中の水銀は、水銀酸化触媒装置により水溶性の２価の水銀に酸化されるので、集塵装置の下流側に湿式脱硫装置を設置し、排ガス中の硫黄酸化物とともに、水銀を吸収液に吸収させて除去できる。この場合、硫黄酸化物の吸収により生成した生成物、例えば、石膏に水銀が含まれから、回収した石膏を利用し難くなるので、湿式脱硫装置の上流側で排ガス中の水銀を除去することが好ましい。例えば、水銀を吸収する吸収液を排ガスに散布し水銀を除去する除去装置を湿式脱硫装置の入口側に設置することができる。また、水銀の吸着剤を排ガスに添加する添加装置と、水銀が吸着した吸着剤を排ガスから除去する除去装置と、を湿式脱硫装置の入口側に設置することができる。なお、排ガス中の水銀は微量であるから、少量の吸収液や吸着材で除去できるので、煤塵を処理する設備に比べて、簡易な設備で使用後の吸収液や吸着剤の処理できる。 By the way, the mercury in the exhaust gas is oxidized into water-soluble divalent mercury by the mercury oxidation catalyst device, so a wet desulfurization device is installed downstream of the dust collector, and mercury is removed together with the sulfur oxide in the exhaust gas. It can be removed by absorption in an absorbing solution. In this case, since the mercury produced in the sulfur oxide absorption, for example, gypsum contains mercury, it becomes difficult to use the collected gypsum, so it is possible to remove mercury in the exhaust gas upstream of the wet desulfurization unit. preferable. For example, a removing device that removes mercury by spreading an absorbing solution that absorbs mercury on exhaust gas can be installed on the inlet side of the wet desulfurization device. Further, an addition device for adding the mercury adsorbent to the exhaust gas and a removal device for removing the adsorbent adsorbed with mercury from the exhaust gas can be installed on the inlet side of the wet desulfurization device. Since the amount of mercury in the exhaust gas is very small, it can be removed with a small amount of absorption liquid or adsorbent, so that the absorption liquid or adsorbent after use can be treated with simple equipment compared to equipment that treats soot and dust.
　一方、三酸化硫黄は湿式脱硫装置で除去し難いから、排ガス中の三酸化硫黄濃度を増加させると、湿式脱硫装置で三酸化硫黄を除去しきれないおそれがある。この場合は、湿式脱硫装置の入口側で三酸化硫黄を還元する還元剤を添加し、三酸化硫黄を、湿式脱硫装置で除去し易い二酸化硫黄に転換することができる。また、三酸化硫黄を除去可能な湿式集塵装置を湿式脱硫装置の出口側に配置し、湿式脱硫装置を通過した三酸化硫黄を排ガスから除去できる。 On the other hand, since sulfur trioxide is difficult to remove with a wet desulfurization apparatus, if the sulfur trioxide concentration in the exhaust gas is increased, there is a possibility that sulfur trioxide cannot be completely removed with the wet desulfurization apparatus. In this case, a reducing agent that reduces sulfur trioxide can be added on the inlet side of the wet desulfurization apparatus, and the sulfur trioxide can be converted into sulfur dioxide that can be easily removed by the wet desulfurization apparatus. Further, a wet dust collector capable of removing sulfur trioxide is disposed on the outlet side of the wet desulfurization device, and sulfur trioxide that has passed through the wet desulfurization device can be removed from the exhaust gas.
　本発明によれば、集塵装置で捕集される煤塵に水銀が付着することを阻害できる。 According to the present invention, it is possible to inhibit mercury from adhering to the dust collected by the dust collector.
本発明の実施形態1の排ガス処理装置のブロック図である。1 is a block diagram of an exhaust gas treatment apparatus according to Embodiment 1 of the present invention. 三酸化硫黄濃度と煤塵への水銀付着の関係を示す図である。It is a figure which shows the relationship between the sulfur trioxide density | concentration and mercury adhesion to dust. 煤塵への水銀付着を三酸化硫黄が阻害する状態を示す図である。It is a figure which shows the state which sulfur trioxide inhibits mercury adhesion to soot dust. 本発明の実施形態２の排ガス処理装置のブロック図である。It is a block diagram of the exhaust gas processing apparatus of Embodiment 2 of the present invention. 本発明の実施形態３の排ガス処理装置のブロック図である。It is a block diagram of the exhaust gas processing apparatus of Embodiment 3 of this invention. 本発明の実施形態４の排ガス処理装置のブロック図である。It is a block diagram of the exhaust gas processing apparatus of Embodiment 4 of this invention.
　以下、本発明を実施の形態に基づいて説明する。
（実施形態１）
　図１に示すように、実施形態1の排ガス処理装置は、火力発電所等に設置され、炭素含有固体燃料、例えば、石炭を燃焼する石炭焚きのボイラ１から排出された排ガスが水銀酸化触媒装置３に導入されるようになっている。水銀酸化触媒装置３には、排ガス中の金属水銀を２価の水銀に酸化する反応を促進する周知の触媒層が備えられている。水銀酸化触媒装置３から排出された排ガスは、空気予熱器５に導入される。空気予熱器５は、例えば、ボイラ１の燃焼用空気を排ガスで加熱するようになっている。空気予熱器５から排出された排ガスは、乾式の集塵装置７に導入される。集塵装置７は、排ガス中の煤塵を捕集して排ガスから除去するようになっている。集塵装置７から排出された排ガスは、後述する湿式集塵装置９に導入されて水銀が除去された後、湿式脱硫装置１１に導入される。湿式脱硫装置１１は、例えば、カルシウム系の吸収液を排ガスに散布し、排ガス中の硫黄酸化物を吸収して石膏に転換し、排ガスから除去するようになっている。湿式脱硫装置１１から排出された排ガスは、例えば、図示していない再加熱器により加熱され煙突１３から大気中に放出されるようになっている。 Hereinafter, the present invention will be described based on embodiments.
(Embodiment 1)
As shown in FIG. 1, the exhaust gas treatment apparatus of Embodiment 1 is installed in a thermal power plant or the like, and the exhaust gas discharged from a coal-fired boiler 1 that burns carbon-containing solid fuel, for example, coal, is a mercury oxidation catalyst apparatus. 3 is introduced. The mercury oxidation catalyst device 3 is provided with a well-known catalyst layer that promotes a reaction of oxidizing metal mercury in exhaust gas to divalent mercury. The exhaust gas discharged from the mercury oxidation catalyst device 3 is introduced into the air preheater 5. The air preheater 5 heats the combustion air of the boiler 1 with exhaust gas, for example. The exhaust gas discharged from the air preheater 5 is introduced into the dry dust collector 7. The dust collector 7 collects the dust in the exhaust gas and removes it from the exhaust gas. The exhaust gas discharged from the dust collector 7 is introduced into a wet dust collector 9 described later and mercury is removed, and then introduced into the wet desulfurizer 11. For example, the wet desulfurization apparatus 11 spreads a calcium-based absorption liquid on exhaust gas, absorbs sulfur oxide in the exhaust gas, converts it into gypsum, and removes it from the exhaust gas. The exhaust gas discharged from the wet desulfurization apparatus 11 is heated by, for example, a reheater (not shown) and is discharged from the chimney 13 into the atmosphere.
　次に、実施形態１の排ガス処理装置の特徴構成を説明する。集塵装置７の入口側の煙道には、煙道内に三酸化硫黄を注入する注入装置１５が設けられている。注入装置１５には、三酸化硫黄が貯蔵された図示していないボンベと、水銀酸化触媒装置３の入口側と空気予熱器５の出口側の二酸化硫黄濃度に基づいて排ガス中の三酸化硫黄濃度を求め、求めた三酸化硫黄濃度に基づいて三酸化硫黄の注入量を調整して、集塵装置７に導入される排ガス中の三酸化硫黄濃度を設定濃度に制御する図示していない制御装置が備えられている。制御装置には、二酸化硫黄の濃度を検出する検出器１７が接続され、検出器１７には、サンプル配管１９、２０を介して排ガスが導入されるようになっている。 Next, the characteristic configuration of the exhaust gas treatment apparatus of Embodiment 1 will be described. The flue on the inlet side of the dust collector 7 is provided with an injection device 15 for injecting sulfur trioxide into the flue. The injection device 15 includes a cylinder (not shown) in which sulfur trioxide is stored, and the sulfur trioxide concentration in the exhaust gas based on the sulfur dioxide concentration on the inlet side of the mercury oxidation catalyst device 3 and on the outlet side of the air preheater 5. A control device (not shown) that controls the sulfur trioxide concentration in the exhaust gas introduced into the dust collector 7 to a set concentration by adjusting the injection amount of sulfur trioxide based on the obtained sulfur trioxide concentration Is provided. A detector 17 for detecting the concentration of sulfur dioxide is connected to the control device, and exhaust gas is introduced into the detector 17 through sample pipes 19 and 20.
　一方、湿式脱硫装置１１の入口側の煙道には、排ガスに三酸化硫黄の還元剤、例えば、ナトリウム成分などを含む塩基性物質を添加する添加装置２１が設けられている。添加装置２１は、三酸化硫黄を二酸化硫黄に還元する周知の還元剤を排ガスに添加するようになっている。添加装置２１が接続された煙道の下流側には、水銀を吸収する吸収液を排ガスに散布する湿式集塵装置９が設けられている。湿式集塵装置９は、水銀を吸収する周知の吸収液を排ガスに散布し、水銀を吸収した吸収液を排出するようになっている。 On the other hand, the flue on the inlet side of the wet desulfurization apparatus 11 is provided with an addition apparatus 21 for adding a basic substance containing a sulfur trioxide reducing agent, such as a sodium component, to the exhaust gas. The adding device 21 adds a known reducing agent that reduces sulfur trioxide to sulfur dioxide to the exhaust gas. On the downstream side of the flue to which the adding device 21 is connected, a wet dust collecting device 9 for spraying an absorbing liquid that absorbs mercury to the exhaust gas is provided. The wet dust collector 9 spreads a well-known absorption liquid that absorbs mercury on exhaust gas, and discharges the absorption liquid that has absorbed mercury.
　このように構成される実施形態１の排ガス処理装置の動作を説明する。ボイラ１から排出された排ガス中の金属水銀は、水銀酸化触媒装置３により水に溶けやすい２価の水銀に転換される。水銀酸化触媒装置３を通過した排ガスは、空気予熱器５でボイラ１の燃焼用空気との熱交換により、例えば、１５０℃～２００℃程度に減温される。減温された排ガスは、集塵装置７に導入され、集塵装置７により排ガス中の煤塵が除去される。煤塵が除去された排ガスは、湿式集塵装置９を通過して、湿式脱硫装置１１で排ガス中の二酸化硫黄や三酸化硫黄といった硫黄酸化物が除去される。 The operation of the exhaust gas treatment apparatus of the first embodiment configured as described above will be described. Metallic mercury in the exhaust gas discharged from the boiler 1 is converted into divalent mercury that is easily dissolved in water by the mercury oxidation catalyst device 3. The exhaust gas that has passed through the mercury oxidation catalyst device 3 is reduced in temperature to, for example, about 150 ° C. to 200 ° C. by heat exchange with the combustion air of the boiler 1 in the air preheater 5. The temperature-reduced exhaust gas is introduced into the dust collector 7, and the dust in the exhaust gas is removed by the dust collector 7. The exhaust gas from which the dust has been removed passes through the wet dust collector 9 and the wet desulfurizer 11 removes sulfur oxides such as sulfur dioxide and sulfur trioxide in the exhaust gas.
　次に、実施形態１の排ガス処理装置の特徴動作を説明する。空気予熱器５から排出された排ガスには、注入装置１５から三酸化硫黄が供給される。この際、排ガス中の三酸化硫黄濃度を設定濃度に制御する制御装置は、検出器１７で検出した水銀酸化触媒装置３の入口側と空気予熱器５の出口側の二酸化硫黄濃度の差から、水銀酸化触媒装置３で三酸化硫黄に転換された二酸化硫黄濃度を求め、排ガス中の三酸化硫黄濃度を推定する。そして、推定された三酸化硫黄濃度と、ボイラ1の使用燃料に応じて予測したボイラ１出口の三酸化硫黄の予測濃度に基づいて、排ガス中の三酸化硫黄濃度を設定濃度に維持するように、ボンベの三酸化硫黄の供給量を調整する。ここで、設定濃度とは、２価の水銀よりも先に煤塵に三酸化硫黄が付着し、煤塵への２価の水銀の付着を阻害できる濃度である。例えば、図２のグラフに示すとおり、集塵装置７の入口側の三酸化硫黄濃度が増加するに従い、煤塵に水銀が付着することによる集塵装置７での水銀除去率が低下する。そして、三酸化硫黄が２０ｐｐｍ以上になると、集塵装置７での水銀除去率はほぼゼロになり、煤塵への水銀の付着もほぼゼロとなる。したがって、三酸化硫黄の設定濃度は、２０ｐｐｍ以上、好ましくは、２５ｐｐｍ～３０ｐｐｍに設定する。これにより、図３に示すとおり、２価の水銀（Ｈｇ２＋）よりも先に煤塵（Ａｓｈ）に三酸化硫黄（ＳＯ３）が付着し、付着した三酸化硫黄により煤塵への水銀の吸着が阻害される。 Next, the characteristic operation of the exhaust gas treatment apparatus of Embodiment 1 will be described. The exhaust gas discharged from the air preheater 5 is supplied with sulfur trioxide from the injection device 15. At this time, the control device for controlling the sulfur trioxide concentration in the exhaust gas to the set concentration is based on the difference in sulfur dioxide concentration between the inlet side of the mercury oxidation catalyst device 3 and the outlet side of the air preheater 5 detected by the detector 17. The concentration of sulfur dioxide converted to sulfur trioxide by the mercury oxidation catalyst device 3 is obtained, and the concentration of sulfur trioxide in the exhaust gas is estimated. Then, based on the estimated sulfur trioxide concentration and the predicted concentration of sulfur trioxide at the outlet of the boiler 1 predicted according to the fuel used by the boiler 1, the sulfur trioxide concentration in the exhaust gas is maintained at the set concentration. Adjust the supply amount of sulfur trioxide in the cylinder. Here, the set concentration is a concentration at which sulfur trioxide adheres to the dust before the bivalent mercury and can inhibit the adhesion of the bivalent mercury to the dust. For example, as shown in the graph of FIG. 2, as the sulfur trioxide concentration on the inlet side of the dust collector 7 increases, the mercury removal rate in the dust collector 7 due to mercury adhering to the dust decreases. And if sulfur trioxide becomes 20 ppm or more, the mercury removal rate in the dust collector 7 will become substantially zero, and the adhesion of mercury to dust will also become substantially zero. Therefore, the set concentration of sulfur trioxide is set to 20 ppm or more, preferably 25 ppm to 30 ppm. As a result, as shown in FIG. 3, sulfur trioxide (SO 3 ) adheres to the dust (Ash) before the divalent mercury (Hg 2+ ), and the adsorbed mercury to the dust by the adsorbed sulfur trioxide. Be inhibited.
　一方、集塵装置７から排出された排ガスに、添加装置２１から三酸化硫黄を二酸化硫黄に還元する還元剤を添加する。これにより、湿式脱硫装置１１で除去し難い三酸化硫黄が、湿式脱硫装置で除去し易い二酸化硫黄に還元される。そして、添加装置２１を通過した排ガスは、湿式集塵装置９に導入され、水銀を吸収する吸収液が散布され、吸収液に排ガス中の水銀が吸収され排ガスから除去される。 Meanwhile, a reducing agent that reduces sulfur trioxide to sulfur dioxide is added from the addition device 21 to the exhaust gas discharged from the dust collector 7. Thereby, sulfur trioxide which is difficult to remove with the wet desulfurization apparatus 11 is reduced to sulfur dioxide which is easy to remove with the wet desulfurization apparatus. Then, the exhaust gas that has passed through the adding device 21 is introduced into the wet dust collector 9, and an absorbing liquid that absorbs mercury is dispersed, and the mercury in the exhaust gas is absorbed into the absorbing liquid and removed from the exhaust gas.
　このように、実施形態１によれば、集塵装置７の上流側に注入した三酸化硫黄により、煤塵への水銀の付着を阻害できる。したがって、煤塵に付着した水銀の溶出防止のため処理を行うことなく、煤塵を、例えば、セメント材料としてリサイクルができる。また、煤塵を埋め立て処理しても水銀による土壌汚染は生じない。なお、集塵装置７で捕集した煤塵には、三酸化硫黄が付着しているが、三酸化硫黄は中和処理により容易に無害化できる。 As described above, according to the first embodiment, the adhesion of mercury to the dust can be inhibited by the sulfur trioxide injected to the upstream side of the dust collector 7. Therefore, the dust can be recycled, for example, as a cement material without performing treatment for preventing the elution of mercury adhering to the dust. In addition, soil contamination by mercury does not occur even if the dust is landfilled. In addition, although the sulfur trioxide has adhered to the dust collected with the dust collector 7, sulfur trioxide can be easily detoxified by the neutralization process.
　また、三酸化硫黄を還元する還元剤により、三酸化硫黄を二酸化硫黄に還元しているので、煤塵への水銀の付着を阻害するために注入した三酸化硫黄を湿式脱硫装置１１で除去できる。 Moreover, since the sulfur trioxide is reduced to sulfur dioxide by the reducing agent that reduces sulfur trioxide, the sulfur trioxide injected to inhibit the adhesion of mercury to the dust can be removed by the wet desulfurization apparatus 11.
　また、湿式脱硫装置１１の上流側で水銀を除去し、水銀を除去した排ガスを湿式脱硫装置１１に導入しているので、湿式脱硫装置１１の脱硫生成物、例えば、石膏に水銀が混入することを防止でき、石膏を建築材等に利用できる。 Moreover, since mercury is removed upstream of the wet desulfurization apparatus 11 and the exhaust gas from which mercury has been removed is introduced into the wet desulfurization apparatus 11, mercury is mixed into the desulfurization product of the wet desulfurization apparatus 11, for example, gypsum. And can be used for building materials.
　なお、窒素酸化物を含む排ガスを処理対象とする場合は、水銀酸化触媒装置３に代えて、脱硝剤を添加して触媒存在下で排ガス中の窒素酸化物を還元する周知の脱硝装置を設置することができる。つまり、脱硝装置に用いられる触媒によっても排ガス中の金属水銀を２価の水銀に酸化できる。 When exhaust gas containing nitrogen oxides is to be treated, a known denitration device is installed instead of the mercury oxidation catalyst device 3 to add a denitration agent to reduce nitrogen oxides in the exhaust gas in the presence of the catalyst. can do. That is, the metal mercury in the exhaust gas can be oxidized to divalent mercury by the catalyst used in the denitration apparatus.
　また、三酸化硫黄を検出する検出器により、集塵装置７の入口側の三酸化硫黄濃度を直接検出することもできるが、三酸化硫黄濃度を即時に検出することが困難な場合は、実施形態１のように、水銀酸化触媒装置３における二酸化硫黄の酸化率から、排ガス中の三酸化硫黄を求めることが好ましい。 In addition, the detector for detecting sulfur trioxide can directly detect the sulfur trioxide concentration on the inlet side of the dust collector 7, but if it is difficult to detect the sulfur trioxide concentration immediately, As in Embodiment 1, it is preferable to obtain sulfur trioxide in the exhaust gas from the oxidation rate of sulfur dioxide in the mercury oxidation catalyst device 3.
　また、燃料中の硫黄分及び燃焼状態等から、集塵装置７の入口側の三酸化硫黄濃度を予測できる場合は、検出器１７を省略して予測濃度に基づいて、排ガス中の三酸化硫黄濃度を設定濃度に維持するように、三酸化硫黄の注入量を調整できる。 If the sulfur trioxide concentration on the inlet side of the dust collector 7 can be predicted from the sulfur content in the fuel, the combustion state, etc., the detector 17 is omitted and the sulfur trioxide in the exhaust gas based on the predicted concentration. The injection amount of sulfur trioxide can be adjusted so as to maintain the concentration at the set concentration.
　また、排ガス中の三酸化硫黄を湿式脱硫装置で除去できる場合は、三酸化硫黄を二酸化硫黄に還元する還元剤を添加する添加装置２１を省略できる。また、添加装置２１を省略し、排ガス中の三酸化硫黄を除去する周知の湿式集塵装置を配置し、排ガス中の三酸化硫黄を除去できる。 Further, when sulfur trioxide in the exhaust gas can be removed by a wet desulfurization apparatus, the addition apparatus 21 for adding a reducing agent that reduces sulfur trioxide to sulfur dioxide can be omitted. Moreover, the addition apparatus 21 is abbreviate | omitted, the well-known wet dust collector which removes sulfur trioxide in exhaust gas can be arrange | positioned, and sulfur trioxide in exhaust gas can be removed.
　また、排ガス中の水銀を除去する湿式集塵装置９を省略し、湿式脱硫装置１１の吸収液に排ガス中の水銀を吸収させて排ガスから除去することができる。この場合、脱硫生成物に水銀が混じることになるが、湿式脱硫装置１１が水銀除去装置も兼ねるので、排ガス処理装置を簡単化できる。 Further, the wet dust collector 9 for removing mercury in the exhaust gas can be omitted, and the mercury in the exhaust gas can be absorbed by the absorption liquid of the wet desulfurization device 11 and removed from the exhaust gas. In this case, mercury is mixed in the desulfurization product, but since the wet desulfurization apparatus 11 also serves as the mercury removal apparatus, the exhaust gas treatment apparatus can be simplified.
　（実施形態２）
　図４に実施形態２の排ガス処理装置のブロック図を示す。実施形態２が実施形態１と相違する点は、湿式集塵装置９に代えて、排ガスに水銀の吸着剤を添加する添加装置２５と、添加装置２５を通過した排ガスから吸着剤を除去する除去装置２７を湿式脱硫装置１１の入口側に配置している点である。その他の構成は実施形態１と同じであることから、同一の符号を付して説明を省略する。 (Embodiment 2)
FIG. 4 shows a block diagram of the exhaust gas treatment apparatus of the second embodiment. The difference between the second embodiment and the first embodiment is that, instead of the wet dust collector 9, an addition device 25 that adds a mercury adsorbent to the exhaust gas, and a removal that removes the adsorbent from the exhaust gas that has passed through the addition device 25. The apparatus 27 is arranged on the inlet side of the wet desulfurization apparatus 11. Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.
　集塵装置７を通過した排ガスには、添加装置２５から水銀の吸着剤、例えば、活性炭が添加される。この際、排ガス中の水銀は、水銀酸化触媒装置３により蒸気圧の低い２価の水銀に酸化されているので、活性炭に吸着する。水銀を吸着させた活性炭は、除去装置２７、例えば、バグフィルタにより捕集され排ガスから除去される。これにより、排ガスから水銀が除去される。バグフィルタで捕集して回収された活性炭は、図示していない再生装置に導入され、温度や圧力をコントロールすることによって活性炭から水銀を脱離させる。水銀を脱離させた活性炭は、添加装置に戻されて再び排ガス中に添加される。これにより、活性炭をリサイクル利用できる。 A mercury adsorbent, for example, activated carbon, is added to the exhaust gas that has passed through the dust collector 7 from the adding device 25. At this time, mercury in the exhaust gas is adsorbed to the activated carbon because it is oxidized by the mercury oxidation catalyst device 3 to divalent mercury having a low vapor pressure. The activated carbon on which mercury is adsorbed is collected by a removing device 27, for example, a bag filter, and removed from the exhaust gas. Thereby, mercury is removed from the exhaust gas. Activated carbon collected and recovered by the bag filter is introduced into a regenerator (not shown), and mercury is desorbed from the activated carbon by controlling temperature and pressure. The activated carbon from which mercury has been desorbed is returned to the adding device and added again into the exhaust gas. Thereby, activated carbon can be recycled.
　これによれば、水銀を除去した排ガスを湿式脱硫装置１１に導入するので、湿式脱硫装置１１で得られる石膏に水銀が混じることを防止でき、純度の高い石膏を得ることができる。また、排ガス中の水銀は微量であるから、少量の吸着剤で水銀を除去できるので、水銀が付着した吸着剤を容易に処理できる。 According to this, since the exhaust gas from which mercury has been removed is introduced into the wet desulfurization apparatus 11, mercury can be prevented from being mixed with the gypsum obtained by the wet desulfurization apparatus 11, and high-purity gypsum can be obtained. Further, since the amount of mercury in the exhaust gas is very small, mercury can be removed with a small amount of adsorbent, so that the adsorbent with mercury attached can be easily treated.
　なお、活性炭に三酸化硫黄が付着すると、付着した三酸化硫黄により活性炭への水銀吸着が阻害されるおそれがある。そのため、添加装置２５の上流側に三酸化硫黄の還元剤を添加して、三酸化硫黄を二酸化硫黄に還元した後に活性炭を添加することが好ましい。 If sulfur trioxide adheres to the activated carbon, the adsorbed sulfur trioxide may inhibit mercury adsorption on the activated carbon. Therefore, it is preferable to add a reducing agent of sulfur trioxide to the upstream side of the adding device 25 and reduce the sulfur trioxide to sulfur dioxide and then add the activated carbon.
　また、集塵装置７の上流側に活性炭等の水銀の吸着剤を添加すると、煤塵と吸着剤を分けられず吸着剤の再生が困難なので、吸着剤の添加位置は、集塵装置７の下流側が好ましい。 Further, if a mercury adsorbent such as activated carbon is added to the upstream side of the dust collector 7, the adsorbent addition position is downstream of the dust collector 7 because it is difficult to regenerate the adsorbent because the dust and adsorbent cannot be separated. The side is preferred.
（実施形態３）
　図５に実施形態３の排ガス処理装置のブロック図を示す。実施形態３が実施形態１と相違する点は、水銀酸化触媒装置３に代えて、脱硝剤を添加して触媒存在下で排ガス中の窒素酸化物を除去する脱硝装置３１を設置している点である。そして、空気予熱器５の入口側で排ガスを分岐し、排ガス中の二酸化硫黄を三酸化硫黄に酸化する硫黄酸化触媒装置３３と、硫黄酸化触媒装置３３から排出される排ガスを集塵装置７の入口側に戻すバイパス管３５とにより、三酸化硫黄の注入装置３７を形成している点である。その他の構成は実施形態１と同じであることから、同一の符号を付して説明を省略する。 (Embodiment 3)
FIG. 5 shows a block diagram of the exhaust gas treatment apparatus of the third embodiment. The difference between the third embodiment and the first embodiment is that, instead of the mercury oxidation catalyst device 3, a denitration device 31 is installed to remove nitrogen oxides in the exhaust gas in the presence of the catalyst by adding a denitration agent. It is. Then, the exhaust gas is branched at the inlet side of the air preheater 5, the sulfur oxidation catalyst device 33 that oxidizes sulfur dioxide in the exhaust gas to sulfur trioxide, and the exhaust gas discharged from the sulfur oxidation catalyst device 33 of the dust collector 7. A sulfur trioxide injection device 37 is formed by the bypass pipe 35 returned to the inlet side. Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.
　次に、実施形態３の排ガス処理装置の動作を説明する。ボイラ１から排出された排ガスは、脱硝装置３１に導入される。脱硝装置３１は、排ガスにアンモニア等の脱硝剤を添加して、脱硝触媒存在下で排ガス中の窒素酸化物を窒素に還元して排ガスから除去する。この際、脱硝触媒により排ガス中の金属水銀は、２価の水銀に酸化される。脱硝装置３１を通過した高温の排ガス、例えば、３５０℃～４００℃の排ガスは、バイパス管３５のファン３９により分岐される。分岐された排ガスは、硫黄酸化触媒装置３３に導入され、排ガス中の二酸化硫黄が三酸化硫黄に酸化される。硫黄酸化触媒装置３３を通過した排ガスは、バイパス管３５を介して集塵装置７の入口側の煙道に戻される。これにより、集塵装置７の入口側に三酸化硫黄を注入できる。 Next, the operation of the exhaust gas treatment apparatus of Embodiment 3 will be described. The exhaust gas discharged from the boiler 1 is introduced into the denitration device 31. The denitration device 31 adds a denitration agent such as ammonia to the exhaust gas, and reduces nitrogen oxides in the exhaust gas to nitrogen in the presence of the denitration catalyst to remove it from the exhaust gas. At this time, metallic mercury in the exhaust gas is oxidized to divalent mercury by the denitration catalyst. High-temperature exhaust gas that has passed through the denitration device 31, for example, 350 ° C. to 400 ° C. exhaust gas, is branched by the fan 39 of the bypass pipe 35. The branched exhaust gas is introduced into the sulfur oxidation catalyst device 33, and sulfur dioxide in the exhaust gas is oxidized to sulfur trioxide. The exhaust gas that has passed through the sulfur oxidation catalyst device 33 is returned to the flue on the inlet side of the dust collector 7 via the bypass pipe 35. Thereby, sulfur trioxide can be injected into the inlet side of the dust collector 7.
　ここで、集塵装置７の入口側の三酸化硫黄濃度の制御について説明する。注入装置３７には、排ガスの分岐量を調整する弁４１と、弁４１の開度を調整する調整装置４３が設けられている。弁４１は、バイパス管３５の流路途中に設けられ、弁４１の開度を調整し、バイパス管３５に分岐される排ガスの流量を調整できるようになっている。調整装置４３には、バイパス管３５に設けられた流量検出器４５の検出値と、検出器１７で検出した硫黄酸化触媒装置３３の入口側と出口側の二酸化硫黄濃度の検出値と、が入力されるようになっている。そして、調整装置４３は、検出器１７で検出された二酸化硫黄濃度の検出値の差と、流量検出器４５で検出した排ガス流量と、から硫黄酸化触媒装置３３の三酸化硫黄の生成量を求めるようになっている。 Here, control of the sulfur trioxide concentration on the inlet side of the dust collector 7 will be described. The injection device 37 is provided with a valve 41 that adjusts the branching amount of the exhaust gas and an adjustment device 43 that adjusts the opening degree of the valve 41. The valve 41 is provided in the middle of the flow path of the bypass pipe 35, and can adjust the flow rate of the exhaust gas branched into the bypass pipe 35 by adjusting the opening degree of the valve 41. The adjustment device 43 receives the detection value of the flow rate detector 45 provided in the bypass pipe 35 and the detection values of the sulfur dioxide concentration on the inlet side and the outlet side of the sulfur oxidation catalyst device 33 detected by the detector 17. It has come to be. Then, the adjustment device 43 obtains the amount of sulfur trioxide generated by the sulfur oxidation catalyst device 33 from the difference between the detected values of the sulfur dioxide concentration detected by the detector 17 and the exhaust gas flow rate detected by the flow rate detector 45. It is like that.
　また、調整装置４３には、ボイラ１から排出された排ガスの流量４７が入力され、この流量４７と燃料中の硫黄分及び燃焼状態に基づいて、排ガス中の三酸化硫黄濃度を推定できるようになっている。 Moreover, the flow rate 47 of the exhaust gas discharged | emitted from the boiler 1 is input into the regulator 43 so that the sulfur trioxide density | concentration in exhaust gas can be estimated based on this flow rate 47, the sulfur content in a fuel, and a combustion state. It has become.
　これらにより、調整装置４３は、集塵装置７に導入される排ガス中の三酸化硫黄濃度を推定し、この推定濃度を設定値に維持するように、弁４１の開度を調整して排ガスの分岐量を調整し三酸化硫黄の生成量を調整する。 Thus, the adjusting device 43 estimates the sulfur trioxide concentration in the exhaust gas introduced into the dust collector 7, and adjusts the opening of the valve 41 so as to maintain this estimated concentration at a set value. Adjust the amount of branching to adjust the amount of sulfur trioxide produced.
　これによれば、排ガス中の二酸化硫黄を利用して排ガスの三酸化硫黄濃度を増加できるので、三酸化硫黄を貯蔵する設備を不要にできる。さらに、外部から三酸化硫黄を補充する作業を不要にできるから、三酸化硫黄の注入に伴う作業を少なくできる。 According to this, since the sulfur trioxide concentration of the exhaust gas can be increased by using sulfur dioxide in the exhaust gas, a facility for storing sulfur trioxide can be eliminated. Further, since the work of replenishing sulfur trioxide from the outside can be made unnecessary, the work accompanying the injection of sulfur trioxide can be reduced.
　なお、ボイラ１から排出された排ガスの流量４７は、ボイラ１の燃焼用空気量の計測信号、あるいは、湿式脱硫装置１１の入口側に設けたガス流量計の計測信号、を利用して求めることができる。また、ガス流量計を集塵装置７の入口側に設置して、その流量測定値の計測信号を利用して求めることができる。 Note that the flow rate 47 of the exhaust gas discharged from the boiler 1 is obtained by using a measurement signal of the combustion air amount of the boiler 1 or a measurement signal of a gas flow meter provided on the inlet side of the wet desulfurization apparatus 11. Can do. Further, a gas flow meter can be installed on the inlet side of the dust collector 7 and obtained using a measurement signal of the flow rate measurement value.
（実施形態４）
　図６に実施形態３の変形例である実施形態４の排ガス処理装置のブロック図を示す。実施形態４が実施形態３と相違する点は、排ガスを分岐する位置を空気予熱器５の入口側に代えて、集塵装置７の出口側にした点である。そして、硫黄酸化触媒装置３３の入口側に、分岐した排ガスを加熱する加熱器４９を配置している点である。その他の構成は実施形態３と同じであることから、同一の符号を付して説明を省略する。 (Embodiment 4)
FIG. 6 shows a block diagram of an exhaust gas treatment apparatus according to the fourth embodiment which is a modification of the third embodiment. The fourth embodiment differs from the third embodiment in that the position where the exhaust gas is branched is changed to the outlet side of the dust collector 7 instead of the inlet side of the air preheater 5. The heater 49 for heating the branched exhaust gas is disposed on the inlet side of the sulfur oxidation catalyst device 33. Since other configurations are the same as those of the third embodiment, the same reference numerals are given and description thereof is omitted.
　集塵装置７の上流側で排ガスを分岐して硫黄酸化触媒装置３３に導入すると、排ガス中の煤塵により硫黄酸化触媒装置３３内の触媒が劣化するおそれがある。そこで、実施形態４の排ガス処理装置は、集塵装置７により煤塵が除去された排ガスを分岐して硫黄酸化触媒装置３３に導入するようにしている。これにより、硫黄酸化触媒装置３３内の触媒が煤塵により劣化することを防止できる。なお、集塵装置７の出口側の排ガスは、空気予熱器５により減温されている。そこで、硫黄酸化触媒装置３３の入口側に加熱器４９を配置し、分岐した排ガスを、二酸化硫黄を三酸化硫黄に酸化する反応が促進される温度、例えば、３５０℃以上に加熱することが好ましい。 If the exhaust gas is branched and introduced into the sulfur oxidation catalyst device 33 on the upstream side of the dust collector 7, the catalyst in the sulfur oxidation catalyst device 33 may be deteriorated by dust in the exhaust gas. Therefore, in the exhaust gas treatment apparatus of Embodiment 4, the exhaust gas from which the dust is removed by the dust collector 7 is branched and introduced into the sulfur oxidation catalyst device 33. Thereby, it can prevent that the catalyst in the sulfur oxidation catalyst apparatus 33 deteriorates by dust. The exhaust gas at the outlet side of the dust collector 7 is reduced in temperature by the air preheater 5. Therefore, it is preferable to arrange a heater 49 on the inlet side of the sulfur oxidation catalyst device 33 and to heat the branched exhaust gas to a temperature at which the reaction of oxidizing sulfur dioxide to sulfur trioxide is promoted, for example, 350 ° C. or more. .
　１　ボイラ
　３　水銀酸化触媒装置
　７　集塵装置
　９　湿式集塵装置
　１１　湿式脱硫装置
　１５　注入装置
　２１　添加装置
　２５　添加装置
　３３　硫黄酸化触媒装置
　３５　バイパス管
　３７　注入装置
　４９　加熱器 DESCRIPTION OF SYMBOLS 1 Boiler 3 Mercury oxidation catalyst apparatus 7 Dust collector 9 Wet dust collector 11 Wet desulfurization apparatus 15 Injection apparatus 21 Addition apparatus 25 Addition apparatus 33 Sulfur oxidation catalyst apparatus 35 Bypass pipe 37 Injection apparatus 49 Heater

Claims (13)

  1. 　炭素含有固体燃料を燃焼させた水銀を含む排ガスが導入され、該排ガス中の水銀を２価の水銀に酸化する水銀酸化触媒装置と、該水銀酸化触媒装置から排出される排ガスが通流する煙道内に三酸化硫黄を注入する注入装置と、該注入装置を通過した排ガス中の煤塵を捕集する集塵装置とを備えてなる排ガス処理装置。 Mercury oxidation catalyst device for introducing exhaust gas containing mercury burned from carbon-containing solid fuel and oxidizing mercury in the exhaust gas to divalent mercury, and smoke passing through exhaust gas discharged from the mercury oxidation catalyst device An exhaust gas treatment apparatus comprising an injection device for injecting sulfur trioxide into the road and a dust collector for collecting the soot in the exhaust gas that has passed through the injection device.
  2. 　請求項１に記載の排ガス処理装置において、
    　前記注入装置は、前記水銀酸化触媒装置の入口側と出口側の二酸化硫黄の検出濃度に基づいて前記集塵装置に導入される排ガス中の三酸化硫黄濃度を求め、求めた三酸化硫黄濃度に基づいて三酸化硫黄の注入量を調整して排ガス中の三酸化硫黄濃度を設定濃度に制御することを特徴とする排ガス処理装置。     The exhaust gas treatment apparatus according to claim 1,
    The injection device determines the sulfur trioxide concentration in the exhaust gas introduced into the dust collector based on the detected sulfur dioxide concentration at the inlet side and the outlet side of the mercury oxidation catalyst device, and obtains the calculated sulfur trioxide concentration. An exhaust gas treatment apparatus characterized by adjusting an injection amount of sulfur trioxide based on the control to control a sulfur trioxide concentration in exhaust gas to a set concentration.
  3. 　請求項１に記載の排ガス処理装置において、
    　前記注入装置は、ボンベに貯蔵された三酸化硫黄を前記煙道内に注入することを特徴とする排ガス処理装置。     The exhaust gas treatment apparatus according to claim 1,
    The injecting apparatus injects sulfur trioxide stored in a cylinder into the flue.
  4. 　請求項３に記載の排ガス処理装置において、
    　前記注入装置は、前記水銀酸化触媒装置の入口側と出口側の二酸化硫黄の検出濃度に基づいて前記集塵装置に導入される排ガス中の三酸化硫黄濃度を求め、求めた三酸化硫黄濃度に基づいて三酸化硫黄の注入量を調整して排ガス中の三酸化硫黄濃度を設定濃度に制御することを特徴とする排ガス処理装置。     The exhaust gas treatment apparatus according to claim 3,
    The injection device determines the sulfur trioxide concentration in the exhaust gas introduced into the dust collector based on the detected sulfur dioxide concentration at the inlet side and the outlet side of the mercury oxidation catalyst device, and obtains the calculated sulfur trioxide concentration. An exhaust gas treatment apparatus characterized by adjusting an injection amount of sulfur trioxide based on the control to control a sulfur trioxide concentration in exhaust gas to a set concentration.
  5. 　請求項１に記載の排ガス処理装置において、
    　前記注入装置は、前記水銀酸化触媒装置から排出される排ガスを分岐して排ガス中の二酸化硫黄を三酸化硫黄に酸化する硫黄酸化触媒装置と、該硫黄酸化触媒装置から排出される排ガスを前記集塵装置の入口側に戻すバイパス管とを備えてなることを特徴とする排ガス処理装置。     The exhaust gas treatment apparatus according to claim 1,
    The injection device branches the exhaust gas discharged from the mercury oxidation catalyst device and oxidizes sulfur dioxide in the exhaust gas to sulfur trioxide, and the exhaust gas discharged from the sulfur oxidation catalyst device is collected. An exhaust gas treatment apparatus comprising a bypass pipe returning to the inlet side of the dust device.
  6. 　請求項５に記載の排ガス処理装置において、
    　前記注入装置は、前記水銀酸化触媒装置の入口側と出口側の二酸化硫黄の検出濃度に基づいて前記集塵装置に導入される排ガス中の三酸化硫黄濃度を求め、求めた三酸化硫黄濃度に基づいて三酸化硫黄の注入量を調整して排ガス中の三酸化硫黄濃度を設定濃度に制御することを特徴とする排ガス処理装置。     The exhaust gas treatment apparatus according to claim 5,
    The injection device determines the sulfur trioxide concentration in the exhaust gas introduced into the dust collector based on the detected sulfur dioxide concentration at the inlet side and the outlet side of the mercury oxidation catalyst device, and obtains the calculated sulfur trioxide concentration. An exhaust gas treatment apparatus characterized by adjusting an injection amount of sulfur trioxide based on the control to control a sulfur trioxide concentration in exhaust gas to a set concentration.
  7. 　請求項１に記載の排ガス処理装置において、
    　前記注入装置は、前記集塵装置から排出される排ガスを分岐して加熱する加熱装置と、該加熱装置から排出される排ガス中の二酸化硫黄を三酸化硫黄に酸化する硫黄酸化触媒装置と、該硫黄酸化触媒装置から排出される排ガスを前記集塵装置の入口側に戻すバイパス管とを備えてなることを特徴とする排ガス処理装置。     The exhaust gas treatment apparatus according to claim 1,
    The injection device includes a heating device that branches and heats the exhaust gas discharged from the dust collector, a sulfur oxidation catalyst device that oxidizes sulfur dioxide in the exhaust gas discharged from the heating device to sulfur trioxide, An exhaust gas treatment apparatus comprising: a bypass pipe that returns exhaust gas discharged from a sulfur oxidation catalyst device to an inlet side of the dust collector.
  8. 　請求項７に記載の排ガス処理装置において、
    　前記注入装置は、前記水銀酸化触媒装置の入口側と出口側の二酸化硫黄の検出濃度に基づいて前記集塵装置に導入される排ガス中の三酸化硫黄濃度を求め、求めた三酸化硫黄濃度に基づいて三酸化硫黄の注入量を調整して排ガス中の三酸化硫黄濃度を設定濃度に制御することを特徴とする排ガス処理装置。     The exhaust gas treatment apparatus according to claim 7,
    The injection device determines the sulfur trioxide concentration in the exhaust gas introduced into the dust collector based on the detected sulfur dioxide concentration at the inlet side and the outlet side of the mercury oxidation catalyst device, and obtains the calculated sulfur trioxide concentration. An exhaust gas treatment apparatus characterized by adjusting an injection amount of sulfur trioxide based on the control to control a sulfur trioxide concentration in exhaust gas to a set concentration.
  9. 　請求項１に記載の排ガス処理装置おいて、
    　前記集塵装置から排出される排ガス中の硫黄酸化物を除去する湿式脱硫装置を備えてなることを特徴とする排ガス処理装置。     In the exhaust gas treatment apparatus according to claim 1,
    An exhaust gas treatment apparatus comprising a wet desulfurization device for removing sulfur oxides in exhaust gas discharged from the dust collector.
  10. 　請求項９に記載の排ガス処理装置において、
    　前記湿式脱硫装置の入口側に、前記排ガスに水銀の吸収液を散布して排ガス中の水銀を除去する除去装置が備えられてなることを特徴とする排ガス処理装置。     The exhaust gas treatment apparatus according to claim 9,
    An exhaust gas treatment apparatus comprising a removal device for removing mercury in exhaust gas by spraying an absorption liquid of mercury on the exhaust gas on an inlet side of the wet desulfurization device.
  11. 　請求項９に記載の排ガス処理装置において、
    　前記湿式脱硫装置の入口側に、前記排ガスに水銀の吸着剤を添加する添加装置と、該添加装置を通過した排ガスから前記吸着剤を除去する除去装置とを備えてなることを特徴とする排ガス処理装置。     The exhaust gas treatment apparatus according to claim 9,
    An exhaust gas comprising an addition device for adding a mercury adsorbent to the exhaust gas and a removal device for removing the adsorbent from the exhaust gas that has passed through the addition device on the inlet side of the wet desulfurization device. Processing equipment.
  12. 　請求項９に記載の排ガス処理装置において、
    　前記湿式脱硫装置の入口側に、前記排ガス中の三酸化硫黄を二酸化硫黄に還元する還元剤を添加する添加装置を備えてなることを特徴とする排ガス処理装置。     The exhaust gas treatment apparatus according to claim 9,
    An exhaust gas treatment apparatus comprising an addition device for adding a reducing agent for reducing sulfur trioxide in the exhaust gas to sulfur dioxide on the inlet side of the wet desulfurization device.
  13. 　請求項９に記載の排ガス処理装置において、
    　前記湿式脱硫装置の出口側に、前記排ガス中の三酸化硫黄を除去する湿式集塵装置を備えてなることを特徴とする排ガス処理装置。
     
    　     The exhaust gas treatment apparatus according to claim 9,
    An exhaust gas treatment apparatus comprising a wet dust collector for removing sulfur trioxide in the exhaust gas on the outlet side of the wet desulfurization apparatus.

PCT/JP2011/004686 2010-08-25 2011-08-24 Exhaust gas processing device WO2012026114A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2010188330A JP2012045465A (en) 2010-08-25 2010-08-25 Apparatus for treating exhaust
JP2010-188330 2010-08-25

Publications (1)

Publication Number Publication Date
WO2012026114A1 true WO2012026114A1 (en) 2012-03-01

Family

ID=45723136

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2011/004686 WO2012026114A1 (en) 2010-08-25 2011-08-24 Exhaust gas processing device

Country Status (2)

Country Link
JP (1) JP2012045465A (en)
WO (1) WO2012026114A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102777921B (en) * 2012-07-12 2014-09-17 广东电网公司电力科学研究院 System and method for carrying out mercury removal and sulfur fixation on pulverized coal boiler by using white mud
CN105983297B (en) * 2015-02-09 2019-06-18 华北电力大学 A kind of coal fired power plant flying dust adsorbent integration is modified and sprays demercuration system

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0731868A (en) * 1992-06-18 1995-02-03 Chemithon Corp:The Method for flue gas adjustment
JP2007167743A (en) * 2005-12-21 2007-07-05 Mitsubishi Heavy Ind Ltd Mercury removal system and mercury removing method
WO2008133044A1 (en) * 2007-04-13 2008-11-06 Babcock-Hitachi Kabushiki Kaisha Exhaust gas purifying method and apparatus
JP2010023004A (en) * 2008-07-24 2010-02-04 Babcock Hitachi Kk Exhaust gas treatment apparatus
JP2010036157A (en) * 2008-08-07 2010-02-18 Mitsubishi Heavy Ind Ltd Exhaust gas treatment device, exhaust gas treatment system and in-exhaust gas mercury oxidizing performance control system
JP2010112679A (en) * 2008-11-10 2010-05-20 Babcock Hitachi Kk Boiler plant
JP2010125377A (en) * 2008-11-27 2010-06-10 Babcock Hitachi Kk Wet-type desulfurization apparatus

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0731868A (en) * 1992-06-18 1995-02-03 Chemithon Corp:The Method for flue gas adjustment
JP2007167743A (en) * 2005-12-21 2007-07-05 Mitsubishi Heavy Ind Ltd Mercury removal system and mercury removing method
WO2008133044A1 (en) * 2007-04-13 2008-11-06 Babcock-Hitachi Kabushiki Kaisha Exhaust gas purifying method and apparatus
JP2010023004A (en) * 2008-07-24 2010-02-04 Babcock Hitachi Kk Exhaust gas treatment apparatus
JP2010036157A (en) * 2008-08-07 2010-02-18 Mitsubishi Heavy Ind Ltd Exhaust gas treatment device, exhaust gas treatment system and in-exhaust gas mercury oxidizing performance control system
JP2010112679A (en) * 2008-11-10 2010-05-20 Babcock Hitachi Kk Boiler plant
JP2010125377A (en) * 2008-11-27 2010-06-10 Babcock Hitachi Kk Wet-type desulfurization apparatus

Also Published As

Publication number Publication date
JP2012045465A (en) 2012-03-08

Similar Documents

Publication Publication Date Title
EP2127728B1 (en) Method and apparatus for treating discharge gas
CA2672577C (en) Exhaust gas treating method and apparatus
JP5385114B2 (en) Combustion exhaust gas mercury removal method and combustion exhaust gas purification device.
EP1570894B1 (en) Method and system for removal of mercury emissions from coal combustion
TWI276460B (en) Exhaust smoke-processing system
JP5035722B2 (en) Regeneration of NT-SCR-catalyst
WO2013179462A1 (en) System and method for treating mercury in flue gas
JP2009166012A (en) Exhaust gas treatment system and its operation method of coal fired boiler
JP2007530256A (en) Bromine addition to improve mercury removal from flue gas
JP2006205128A (en) Removal apparatus of trace harmful substance in exhaust gas and its operation method
TW201231147A (en) Exhaust gas treatment method and apparatus
PT2373927E (en) Processing of off-gas from waste treatment
JP2006263700A (en) Method and system for removing mercury in exhaust gas
WO2011142376A1 (en) Emission gas processing system with carbon dioxide chemical absorption device
JP2010058067A (en) Method for regenerating denitration catalyst, unit for regenerating denitration catalyst and apparatus for treating exhaust gas by using the unit
JP4936002B2 (en) Exhaust gas treatment method and exhaust gas treatment apparatus
WO2012026114A1 (en) Exhaust gas processing device
JP2004218996A (en) Ammonia-containing waste gas treating device and method
JPH119962A (en) Waste gas treatment method and apparatus therefor
US20180050304A1 (en) Systems and methods for post combustion mercury control using sorbent injection and wet scrubbing
JP3383051B2 (en) Exhaust gas purification method and apparatus
JP2008030017A (en) Removal apparatus of trace harmful substance in exhaust gas and its operation method
JP2013142501A (en) Exhaust gas treatment device and exhaust gas treatment method
JP5299600B2 (en) Exhaust gas treatment method and exhaust gas treatment apparatus
JP2009221922A (en) Exhaust emission control device

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 11819590

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 11819590

Country of ref document: EP

Kind code of ref document: A1