WO2023007973A1 - Exhaust gas treatment apparatus - Google Patents

Exhaust gas treatment apparatus Download PDF

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Publication number
WO2023007973A1
WO2023007973A1 PCT/JP2022/023886 JP2022023886W WO2023007973A1 WO 2023007973 A1 WO2023007973 A1 WO 2023007973A1 JP 2022023886 W JP2022023886 W JP 2022023886W WO 2023007973 A1 WO2023007973 A1 WO 2023007973A1
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Prior art keywords
exhaust gas
gas treatment
heat exchanger
treatment apparatus
air
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PCT/JP2022/023886
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French (fr)
Japanese (ja)
Inventor
俊大 福田
弘貢 長安
卓也 岡本
直行 神山
浩一郎 岩下
Original Assignee
三菱重工業株式会社
三菱パワー株式会社
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Publication of WO2023007973A1 publication Critical patent/WO2023007973A1/en

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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
    • B01D53/14—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 by absorption
    • 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
    • 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
    • B01D53/77—Liquid phase processes
    • B01D53/78—Liquid phase processes with gas-liquid contact
    • 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
    • B01D53/81—Solid phase processes
    • B01D53/83—Solid phase processes with moving reactants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/02—Plant or installations having external electricity supply
    • B03C3/16—Plant or installations having external electricity supply wet type

Definitions

  • the present disclosure relates to an exhaust gas treatment device.
  • This application claims priority based on Japanese Patent Application No. 2021-125324 filed with the Japan Patent Office on July 30, 2021, the contents of which are incorporated herein.
  • Sulfur trioxide (SO 3 ) is contained in exhaust gas generated by burning fossil fuels such as petroleum and coal. If the temperature of the flue gas containing SO3 is above the dew point of SO3 , SO3 exists as SO3 gas in the flue gas. SO3 must be removed from the flue gas.
  • a wet-type electrostatic precipitator is installed downstream of a wet-type desulfurization device, and an exhaust gas treatment device that removes sulfuric acid present in the form of mist in the exhaust gas. is sometimes used.
  • the wet type electrostatic precipitator for treating exhaust gas containing high concentrations of SO 3 is associated with an increase in equipment size and a large amount of alkaline chemical (caustic soda) consumption, resulting in increased costs and poor economic efficiency.
  • Patent Document 2 discloses an exhaust gas flow on the exhaust gas inlet side of a heat exchanger that is arranged across the exhaust gas flow paths on the upstream side and the downstream side of the wet desulfurization apparatus.
  • An exhaust gas treatment device is described in which the flue gas is sprayed with a powdered alkaline absorbent to reduce the SO 3 concentration in the exhaust gas.
  • a large amount of powdered alkaline absorbent must be sprayed into the flue gas, and it is difficult to remove the high concentration powder contained in the flue gas before it is released into the atmosphere.
  • the exhaust gas treatment apparatuses described in Patent Documents 1 and 2 can remove SO3 from exhaust gas, but in order to treat exhaust gas containing high concentrations of SO3 , a large amount of chemicals and high-performance Since additional equipment is required, there is a disadvantage that the cost increases and economic efficiency is poor.
  • At least one embodiment of the present disclosure aims to provide an exhaust gas treatment apparatus that suppresses cost increases and has economic superiority.
  • an exhaust gas treatment apparatus for treating exhaust gas discharged from a combustion device, comprising: a charging device for charging a powdery alkaline absorbent into the exhaust gas; A wet desulfurization device that desulfurizes the exhaust gas by contacting the exhaust gas containing an alkali absorbent with an absorbent, and heats the exhaust gas before being desulfurized in the wet desulfurization device and the air supplied to the combustion device. and a heat exchanger for exchanging.
  • the air heated by exchanging heat with the exhaust gas before being desulfurized in the wet desulfurization apparatus is supplied to the combustion apparatus, thereby improving the operation efficiency of the combustion apparatus.
  • the operating efficiency of the entire plant, including the equipment and exhaust gas treatment equipment, is improved. This improvement in operating efficiency suppresses the increase in costs due to the installation of an exhaust gas treatment apparatus containing high concentrations of SO 3 , and enables exhaust gas treatment with improved economic efficiency of the entire plant.
  • FIG. 1 is a configuration schematic diagram of a plant including an exhaust gas treatment apparatus according to Embodiment 1 of the present disclosure
  • FIG. 1 is a configuration schematic diagram of a wet electrostatic precipitator provided in an exhaust gas treatment apparatus according to Embodiment 1 of the present disclosure
  • FIG. 2 is a schematic diagram of the configuration of a plant including an exhaust gas treatment apparatus according to Embodiment 2 of the present disclosure
  • the plant 1 includes a boiler 2 that is a combustion device, an exhaust gas treatment device 3 according to Embodiment 1 of the present disclosure, and a chimney 4.
  • the exhaust gas treatment device 3 discharges from the boiler 2 It is intended to treat the exhaust gas that is produced.
  • the flue gas treatment device 3 includes a charging device 11 for charging a powdered alkali absorbent, such as powdered calcium carbonate, into a flue 5 through which the flue gas flows, and bringing the flue gas containing the alkali absorbent into contact with the absorbent.
  • the configuration of the injection device 11 is not limited, for example, it is possible to use a device that injects a powdered alkali absorbent into the flue 5 together with compressed air.
  • an air line 18 through which air supplied to the boiler 2 flows is provided.
  • the air line 18 has one end connected to the boiler 2 , the other end provided with a blower 19 , and configured to pass through the heat exchanger 13 .
  • the exhaust gas treatment device 3 is not an essential component, but includes a denitrification device 14 for denitrifying the exhaust gas, a heat exchanger 15 for exchanging heat between the exhaust gas flowing out of the denitrification device 14 and the air supplied to the boiler 2, and wet desulfurization.
  • a dry dust remover 16 e.g., a dry electrostatic precipitator or bag filter
  • the dust remover 17 can use either a dry dust remover or a wet dust remover.
  • dry dust remover 17 for example, a bag filter can be used, and as the wet dust remover 17, for example, a wet electrostatic precipitator can be used. If heat exchanger 15 is provided, air line 18 is arranged to pass through heat exchanger 15 as well as heat exchanger 13 .
  • FIG. 2 shows an example of the configuration when the dust remover 17 is a wet-type electrostatic precipitator. Even if the dust remover 17 is a wet electrostatic precipitator, it is not limited to the wet electrostatic precipitator having the structure shown in FIG. 2, and the structure shown in FIG. 2 is merely an example of the wet electrostatic precipitator.
  • the dust remover 17 includes a housing 21 communicating with the flue 5. Inside the housing 21, one or a plurality of electrodes 22 and a cleaning liquid containing an alkaline chemical (for example, caustic soda) for adjusting pH are contained. and a circulation line 24 for circulating the cleaning liquid so as to return the cleaning liquid sprayed onto the electrode 22 to the nozzles 23 again. A pump 25 or the like is provided in the circulation line 24 to circulate the cleaning liquid.
  • an alkaline chemical for example, caustic soda
  • the circulation line 24 may be provided with a branch line 26 that communicates between two different positions P 1 and P 2 of the circulation line 24 , and the branch line 26 may be provided with a separator 27 .
  • the separation device 27 is for separating solid substances contained in the cleaning liquid from the cleaning liquid, and may be, for example, a filter for filtering solid substances having a particle size larger than an arbitrary size.
  • a buffer tank 28 is provided to hold the slurry containing the solid matter separated by the separation device 27, and the slurry is supplied to the wet desulfurization device 12 via a line 29 connecting the buffer tank 28 and the wet desulfurization device 12. may be configured.
  • the buffer tank 28 is provided with an agitator for agitating the slurry to be retained so as not to deposit solid matter.
  • the flue gas treatment device 3 when powdered calcium carbonate is fed from the feeding device 11 into the flue 5 as an alkali absorbent, the powdered calcium carbonate is mixed with the flue gas flowing through the flue 5 .
  • the exhaust gas containing powdered calcium carbonate is pressurized by the blower 19 and is cooled by exchanging heat with the air flowing through the air line 18. If the temperature of the exhaust gas is higher than the dew point of SO3 , SO3 exists as a gas in the exhaust gas , but when the exhaust gas is cooled to below the dew point of SO3 , SO3 condenses. As SO 3 condenses, SO 3 is incorporated into calcium carbonate. That is, SO 3 is removed from the exhaust gas.
  • the air heated by exchanging heat with the exhaust gas in the heat exchanger 13 is supplied to the boiler 2 .
  • the exhaust gas treatment device 3 is provided with the heat exchanger 15 , the air is further heated by exchanging heat with the exhaust gas in the heat exchanger 15 and supplied to the boiler 2 .
  • the air heated in the heat exchangers 13 and 15 in the heat exchanger 13 is supplied to the boiler 2, so that the operation efficiency of the boiler 2 is improved, so that the operation efficiency of the plant 1 as a whole is improved.
  • the exhaust gas cooled in the heat exchanger 13 flows into the wet desulfurization device 12 .
  • the exhaust gas is brought into gas-liquid contact with an absorption liquid (for example, an aqueous solution of calcium carbonate), whereby sulfur dioxide (SO 2 ) gas and SO 3 gas in the exhaust gas are removed (desulfurized).
  • an absorption liquid for example, an aqueous solution of calcium carbonate
  • SO 2 sulfur dioxide
  • SO 3 gas in the exhaust gas are removed (desulfurized).
  • the powdery calcium carbonate contained in the exhaust gas is also removed from the exhaust gas by being mostly taken into the absorbing liquid. If the exhaust gas treatment device 3 does not have the dust removal device 17, the exhaust gas that has flowed out of the wet desulfurization device 12 is released into the atmosphere through the chimney 4.
  • the cleaning liquid flowing through the circulation line 24 is sprayed from the nozzle 23 onto the electrode 22, so that the solid matter adhering to the electrode 22 is washed away from the electrode 22 and incorporated into the cleaning liquid.
  • the cleaning liquid flows out from the housing 21 and circulates through the circulation line 24 .
  • the cleaning liquid is again supplied to the nozzle 23 by the pump 25 and sprayed onto the electrode 22 .
  • the circulation line 24 When the circulation line 24 is provided with the branch line 26 and the separation device 27, part of the cleaning liquid flowing through the circulation line 24 flows through the branch line 26 and flows into the separation device 27 during the cleaning operation.
  • the washing liquid In the separation device 27, the washing liquid is separated into a slurry containing a high concentration of solid matter and a slurry containing a low concentration of solid matter. If the solid matter concentration in the cleaning liquid is high, the nozzle 23 and the circulation line 24 may be clogged. However, if the separation device 27 is provided, the solid substances in the cleaning liquid are removed by the separation device 27 and the solid substance concentration is lowered, so that the possibility of clogging the nozzle 23 or the circulation line 24 can be reduced.
  • the slurry containing low-concentration solid substances separated by the separation device 27 is reused as a cleaning liquid that flows through the circulation line 24 .
  • the slurry containing the high-concentration solid matter separated by the separation device 27 contains a large amount of calcium carbonate contained in the absorbent used in the wet desulfurization device 12, it passes through the line 29 to the wet desulfurization device. 12, it can be reused as part of the absorption liquid.
  • the washing liquid circulated by the washing operation exhibits acidity, which may cause corrosion of the equipment. be.
  • caustic soda as an alkaline chemical into the circulating liquid tank 41 to adjust the pH.
  • the powdery calcium carbonate contained in the exhaust gas that has escaped from the wet desulfurization device 12 is removed by the downstream dust removal device 17 and dissolved in the circulating water, so that the pH can be prevented from decreasing without adding caustic soda. , the consumption of alkali chemicals (for example, caustic soda) can be reduced, and the cost increase can be further suppressed.
  • the air heated by exchanging heat with the exhaust gas before being desulfurized in the wet desulfurization apparatus 12 is supplied to the boiler 2, whereby the boiler 2 , the operating efficiency of the entire plant 1 including the boiler 2 and the exhaust gas treatment device 3 is improved.
  • This improvement in operating efficiency suppresses an increase in costs due to the installation of an exhaust gas treatment apparatus containing high concentrations of SO 3 , and enables exhaust gas treatment with improved economic efficiency of the entire plant.
  • Embodiment 2 Next, an exhaust gas treatment apparatus according to Embodiment 2 will be described.
  • the air flowing into the boiler 2 and the exhaust gas flowing into the exhaust gas treatment device 3 are heat-exchanged. need to implement. Therefore, in the exhaust gas treatment apparatus according to the second embodiment, air heating operation control in the heat exchanger 13 is added to the first embodiment.
  • the same reference numerals are given to the same components as those of the first embodiment, and detailed description thereof will be omitted.
  • the air line 18 is provided with a bypass line 31 that bypasses the heat exchanger 13, and the bypass line 31 is provided with a bypass line 31
  • An adjusting device 32 eg, a flow rate adjusting damper
  • a temperature sensor 33 first temperature detection device that detects the temperature of the exhaust gas that has flowed out of the heat exchanger 13 is provided in the flue 5, and the adjustment device 32 is controlled based on the value detected by the temperature sensor 33 (for example, a flow rate adjustment damper may be controlled).
  • the temperature sensor 33 detects the temperature of the exhaust gas flowing into the heat exchanger 13.
  • the temperature measurement value or the temperature measurement value of the air flowing out of the heat exchanger 13 may be used to control the adjustment device 32 .
  • FIG. 3 shows a steam air heater 34a as an example of the heating device 34.
  • a steam supply line 35 for supplying steam to the steam air heater 34a is connected to the steam air heater 34a.
  • the steam supply line 35 is provided with a steam supply amount adjustment valve 36 for adjusting the flow rate of steam flowing through the steam supply line 35 .
  • a temperature sensor 37 (second temperature detection device) for detecting the temperature of the exhaust gas flowing out of the heat exchanger 15 is provided in the flue 5, and the opening degree of the steam supply amount adjustment valve 36 is determined based on the value detected by the temperature sensor 37. may be controlled.
  • the temperature sensor 37 detects the temperature of the exhaust gas flowing into the heat exchanger 15.
  • the opening degree of the steam supply amount adjustment valve 36 may be controlled using the temperature measurement value, the temperature measurement value of the exhaust gas flowing out of the dust remover 16, or the temperature measurement value of the air flowing out of the heat exchanger 15. Other configurations are the same as those of the first embodiment.
  • Embodiment 1 since the air heated by the heat exchanger 13 is supplied to the boiler 2, the operation efficiency of the boiler 2 is improved. , there is a suitable temperature of the air depending on the operating conditions of the boiler 2 . On the other hand, if the air is heated more than necessary in the heat exchanger 13, the exhaust gas will be cooled too much. If the temperature of is too low, the exhaust gas flowing out of the heat exchanger 15 will be cooled too much, and it cannot be denied that the operation of the exhaust gas treatment apparatus after the heat exchanger 15 will be adversely affected. Furthermore, under conditions where the atmospheric temperature fluctuates greatly, it is necessary to control the influence of the temperature change of the air sucked by the blower 19 on the heat exchanger 15 .
  • the flow rate of the air supplied to the heat exchanger 13 can be reduced.
  • the flow rate of the air flowing through the bypass line 31 can be adjusted by the adjusting device 32 , in other words, the adjusting device 32 can adjust the flow rate of the air supplied to the heat exchanger 13 . Since the amount of air supplied to the heat exchanger 13 can be adjusted in this way, the temperature of the air supplied to the boiler 2 can be adjusted. be able to.
  • the exhaust gas temperature suitable for the operation of the exhaust gas treatment apparatus after the heat exchanger 15 can be maintained.
  • the adjustment device 32 is controlled based on the value detected by the temperature sensor 33, and the air supplied to the heat exchanger 13 can be adjusted.
  • the amount of air supplied to the heat exchanger 13 can be adjusted based on the temperature of the exhaust gas heat-exchanged with the air in the heat exchanger 13, so the temperature of the air supplied to the boiler 2 can be adjusted. Therefore, the accuracy of air temperature adjustment is improved, and air more suitable for the operating state of the boiler 2 can be supplied to the boiler 2 .
  • the heat exchanger 15 when the heat exchanger 15 is installed, the exhaust gas temperature suitable for the operation of the exhaust gas treatment apparatus after the heat exchanger 15 can be maintained.
  • the temperature of the air can be adjusted according to the operating conditions of the boiler 2.
  • the air flowing through the bypass line 31 is heated by the heating device 34 to adjust the temperature of the air supplied to the boiler 2 to an appropriate temperature according to the operating conditions of the boiler 2. can do.
  • the heating device 34 is a steam air heater 34a
  • the temperature of the air supplied to the boiler 2 is adjusted by controlling the opening degree of the steam supply amount adjustment valve 36 to adjust the flow rate of the steam supplied to the steam air heater 34a. Adjustments can be made.
  • the exhaust gas temperature suitable for the operation of the exhaust gas treatment apparatus after the heat exchanger 15 can be maintained.
  • heating is performed by controlling the opening of the steam supply amount adjustment valve 36 based on the value detected by the temperature sensor 37.
  • Device 34 can regulate the heating of the air. Thereby, the temperature of the air supplied to the boiler 2 can be controlled more appropriately.
  • the heat exchanger 15 is installed, the exhaust gas temperature suitable for the operation of the exhaust gas treatment apparatus after the heat exchanger 15 can be maintained.
  • An exhaust gas treatment device includes: An exhaust gas treatment device (3) for treating exhaust gas discharged from a combustion device (boiler 2), A charging device (11) for charging a powdery alkali absorbent into the exhaust gas; a wet desulfurization device (12) for desulfurizing the exhaust gas by bringing the exhaust gas containing the alkali absorbent into contact with an absorbent; A heat exchanger (13) is provided for exchanging heat between the exhaust gas before being desulfurized in the wet desulfurization device (12) and the air supplied to the combustion device (2).
  • the air heated by exchanging heat with the exhaust gas before being desulfurized in the wet desulfurization apparatus is supplied to the combustion apparatus, thereby improving the operation efficiency of the combustion apparatus.
  • the operating efficiency of the entire plant, including the equipment and exhaust gas treatment equipment, is improved. This improvement in operating efficiency suppresses an increase in costs due to the installation of the exhaust gas treatment apparatus, thereby enabling exhaust gas treatment with improved economic efficiency of the entire plant.
  • An exhaust gas treatment device is the exhaust gas treatment device of [1], a bypass line (31) through which at least part of the air supplied to the heat exchanger (13) bypasses the heat exchanger (13); and an adjusting device (32) for adjusting the flow rate of the air flowing through the bypass line (31).
  • An exhaust gas treatment device is the exhaust gas treatment device of [2], A first temperature detection device (temperature sensor 33) that detects the temperature of the exhaust gas heat-exchanged with the air in the heat exchanger (13), Based on the value detected by the first temperature detection device (33), the adjustment device (32) adjusts the flow rate of the air flowing through the bypass line (31).
  • the amount of air supplied to the heat exchanger can be adjusted based on the temperature of the exhaust gas that has undergone heat exchange with the air in the heat exchanger. can be adjusted, the accuracy of air temperature adjustment is improved, and air more suitable for the operating conditions of the combustion device can be supplied to the combustion device.
  • An exhaust gas treatment device is the exhaust gas treatment device of either [2] or [3], A heating device (34) is provided for heating the air flowing through the bypass line (31).
  • An exhaust gas treatment device is the exhaust gas treatment device of [4], A second temperature detection device (temperature sensor 37) that detects the temperature of the exhaust gas discharged from the combustion device (2), Based on the value detected by the second temperature detection device (37), the heating device (34) adjusts the heating of the air.
  • An exhaust gas treatment device is the exhaust gas treatment device according to any one of [1] to [5], In the heat exchanger, the exhaust gas containing the alkali absorbent is cooled to a temperature below the dew point of SO3.
  • An exhaust gas treatment device is the exhaust gas treatment device according to any one of [1] to [6], A dust remover (17) for removing solid substances from the exhaust gas desulfurized in the wet desulfurization device (12) is provided.
  • An exhaust gas treatment device is the exhaust gas treatment device of [7],
  • the dust remover (17) is a wet electrostatic precipitator,
  • the wet electrostatic precipitator is an electrode (22) for collecting the solid matter; a nozzle (23) for spraying a cleaning liquid onto the electrode (22); a circulation line (24) for circulating the cleaning liquid so as to return the cleaning liquid sprayed on the electrode (22) to the nozzle (23),
  • Said circulation line (24) comprises a branch line (26) communicating between two different positions (P 1 , P 2 ) of said circulation line (24).
  • a separation device (27) is provided for separating the contained solid matter from the washing liquid.
  • the dust remover is a wet-type electrostatic precipitator, if the concentration of solid substances in the cleaning liquid is high, the cleaning liquid circulation line may be clogged.
  • the concentration of solid substances in the cleaning liquid is high, the cleaning liquid circulation line may be clogged.
  • An exhaust gas treatment device is the exhaust gas treatment device of [8], a buffer tank (28) for retaining the slurry containing the solid matter separated by the separation device (27); A line (29) communicating between the buffer tank (28) and the wet desulfurization device (12), The slurry in the buffer tank (28) is supplied to the wet desulfurization unit (12) as the absorbent through the line (29).
  • the amount of alkali absorbent used in the wet desulfurization device can be saved, so the operating cost of the exhaust gas treatment device can be reduced.

Abstract

An exhaust gas treatment apparatus, which treats exhaust gas discharged from a combustion device, comprises: a charging device that charges a powdered alkaline absorbent into the exhaust gas; a wet desulfurization device that desulfurizes the exhaust gas by contacting the exhaust gas including the alkaline absorbent with an absorbing liquid; and a heat exchanger that exchanges heat between the exhaust gas before desulfurization in the wet desulfurization device and the air supplied to the combustion device.

Description

排ガス処理装置Exhaust gas treatment device
　本開示は、排ガス処理装置に関する。
　本願は、２０２１年７月３０日に日本国特許庁に出願された特願２０２１－１２５３２４号に基づき優先権を主張し、その内容をここに援用する。 The present disclosure relates to an exhaust gas treatment device.
This application claims priority based on Japanese Patent Application No. 2021-125324 filed with the Japan Patent Office on July 30, 2021, the contents of which are incorporated herein.
　石油や石炭等の化石燃料を燃焼した排ガス中には三酸化硫黄（ＳＯ３）が含まれる。ＳＯ３を含む排ガスの温度がＳＯ３の露点以上であれば、ＳＯ３は排ガス中でＳＯ３ガスとして存在するが、排ガスの温度がＳＯ３の露点以下になると、有害で腐食性のある液体状の硫酸となるため、排ガスからＳＯ３を除去する必要がある。 Sulfur trioxide (SO 3 ) is contained in exhaust gas generated by burning fossil fuels such as petroleum and coal. If the temperature of the flue gas containing SO3 is above the dew point of SO3 , SO3 exists as SO3 gas in the flue gas. SO3 must be removed from the flue gas.
　ＳＯ３を除去する装置としては、例えば特許文献１に記載されているように、湿式脱硫装置の下流側に湿式電気集塵機を設置し、排ガス中にミスト状で存在する硫酸を除去する排ガス処理装置が用いられることがある。しかし、高濃度のＳＯ３を含む排ガスを処理する湿式電気集塵機は、設備大型化やアルカリ薬剤（苛性ソーダ）の多量消費を伴うため、コスト増加となり経済性が悪いという欠点がある。 As a device for removing SO 3 , for example, as described in Patent Document 1, a wet-type electrostatic precipitator is installed downstream of a wet-type desulfurization device, and an exhaust gas treatment device that removes sulfuric acid present in the form of mist in the exhaust gas. is sometimes used. However, the wet type electrostatic precipitator for treating exhaust gas containing high concentrations of SO 3 is associated with an increase in equipment size and a large amount of alkaline chemical (caustic soda) consumption, resulting in increased costs and poor economic efficiency.
　特許文献１とは異なる排ガス処理装置として、例えば特許文献２には、湿式脱硫装置の前流側と後流側の排ガス流路に掛け渡して配置される熱交換器の排ガス入口側の排ガス流路に粉末状アルカリ吸収剤を噴霧し、排ガス中のＳＯ３濃度を下げる排ガス処理装置が記載されている。しかし、高濃度のＳＯ３を含む排ガスを処理するためには大量の粉末状のアルカリ吸収剤を排ガス中に噴霧する事となり、排ガス中に含まれる高濃度粉末を大気放出前に除去することが必要であり、そのための高性能除塵装置の追加と、除塵された大量の粉末の処理・操作に伴う装置内の堆積や閉塞を防止できる処置の追加が必要となり、結果的に、前記特許文献１と同様に、特許文献２においてもコスト増加となり経済性が悪いという欠点がある。 As an exhaust gas treatment device different from Patent Document 1, for example, Patent Document 2 discloses an exhaust gas flow on the exhaust gas inlet side of a heat exchanger that is arranged across the exhaust gas flow paths on the upstream side and the downstream side of the wet desulfurization apparatus. An exhaust gas treatment device is described in which the flue gas is sprayed with a powdered alkaline absorbent to reduce the SO 3 concentration in the exhaust gas. However, in order to treat flue gas containing high concentrations of SO3 , a large amount of powdered alkaline absorbent must be sprayed into the flue gas, and it is difficult to remove the high concentration powder contained in the flue gas before it is released into the atmosphere. Therefore, it is necessary to add a high-performance dust removal device for that purpose, and to add a measure that can prevent accumulation and blockage in the device accompanying the processing and operation of a large amount of dust-removed powder. Similarly to Patent Document 2, there is a drawback that the cost is increased and the economy is poor.
特開２００２－３６４８３０号公報JP-A-2002-364830 特開２０１３－３４９６５号公報JP 2013-34965 A
　上記の通り、特許文献１及び２に記載の排ガス処理装置は、排ガスからＳＯ３を除去することはできるものの、高濃度のＳＯ３を含む排ガスを処理するためには、大量の薬剤や高性能の追加設備が必要となることから、コスト増加となり経済性が悪いという欠点がある。 As described above, the exhaust gas treatment apparatuses described in Patent Documents 1 and 2 can remove SO3 from exhaust gas, but in order to treat exhaust gas containing high concentrations of SO3 , a large amount of chemicals and high-performance Since additional equipment is required, there is a disadvantage that the cost increases and economic efficiency is poor.
　上述の事情に鑑みて、本開示の少なくとも１つの実施形態は、コスト増加を抑制し経済優位性を有する排ガス処理装置の提供を目的とする。 In view of the above circumstances, at least one embodiment of the present disclosure aims to provide an exhaust gas treatment apparatus that suppresses cost increases and has economic superiority.
　上記目的を達成するため、本開示に係る排ガス処理装置は、燃焼装置から排出される排ガスを処理する排ガス処理装置であって、前記排ガスに粉末状のアルカリ吸収剤を投入する投入装置と、前記アルカリ吸収剤を含んだ排ガスと吸収液とを接触させることにより前記排ガスの脱硫を行う湿式脱硫装置と、前記湿式脱硫装置において脱硫される前の排ガスと前記燃焼装置に供給される空気とを熱交換する熱交換器とを備える。 In order to achieve the above object, an exhaust gas treatment apparatus according to the present disclosure is an exhaust gas treatment apparatus for treating exhaust gas discharged from a combustion device, comprising: a charging device for charging a powdery alkaline absorbent into the exhaust gas; A wet desulfurization device that desulfurizes the exhaust gas by contacting the exhaust gas containing an alkali absorbent with an absorbent, and heats the exhaust gas before being desulfurized in the wet desulfurization device and the air supplied to the combustion device. and a heat exchanger for exchanging.
　本開示の排ガス処理装置によれば、湿式脱硫装置において脱硫される前の排ガスと熱交換することにより加熱された空気が燃焼装置に供給され、これにより燃焼装置の運転効率が向上するので、燃焼装置及び排ガス処理装置を含むプラント全体の運転効率が向上する。この運転効率の向上が、高濃度のＳＯ３を含む排ガス処理装置の設置に基づくコスト増加を抑制し、プラント全体の経済性を向上させた排ガス処理が可能となる。 According to the exhaust gas treatment apparatus of the present disclosure, the air heated by exchanging heat with the exhaust gas before being desulfurized in the wet desulfurization apparatus is supplied to the combustion apparatus, thereby improving the operation efficiency of the combustion apparatus. The operating efficiency of the entire plant, including the equipment and exhaust gas treatment equipment, is improved. This improvement in operating efficiency suppresses the increase in costs due to the installation of an exhaust gas treatment apparatus containing high concentrations of SO 3 , and enables exhaust gas treatment with improved economic efficiency of the entire plant.
本開示の実施形態１に係る排ガス処理装置を含むプラントの構成模式図である。1 is a configuration schematic diagram of a plant including an exhaust gas treatment apparatus according to Embodiment 1 of the present disclosure; FIG. 本開示の実施形態１に係る排ガス処理装置に設けられる湿式電気集塵機の構成模式図である。1 is a configuration schematic diagram of a wet electrostatic precipitator provided in an exhaust gas treatment apparatus according to Embodiment 1 of the present disclosure; FIG. 本開示の実施形態２に係る排ガス処理装置を含むプラントの構成模式図である。FIG. 2 is a schematic diagram of the configuration of a plant including an exhaust gas treatment apparatus according to Embodiment 2 of the present disclosure;
　以下、本開示の実施形態による排ガス処理装置について、図面に基づいて説明する。以下で説明する実施形態は、本開示の一態様を示すものであり、この開示を限定するものではなく、本開示の技術的思想の範囲内で任意に変更可能である。 An exhaust gas treatment apparatus according to an embodiment of the present disclosure will be described below based on the drawings. The embodiments described below represent one aspect of the present disclosure, do not limit the disclosure, and can be arbitrarily changed within the scope of the technical idea of the present disclosure.
（実施形態１）
＜本開示の実施形態１に係る排ガス処理装置の構成＞
　図１に示されるように、プラント１は、燃焼装置であるボイラ２と、本開示の実施形態１に係る排ガス処理装置３と、煙突４とを備え、排ガス処理装置３は、ボイラ２から排出される排ガスを処理するためのものである。排ガス処理装置３は、排ガスが流通する煙道５に粉末状のアルカリ吸収剤、例えば粉末状の炭酸カルシウムを投入する投入装置１１と、アルカリ吸収剤を含んだ排ガスと吸収液とを接触させることにより排ガスの脱硫を行う湿式脱硫装置１２と、湿式脱硫装置１２において脱硫される前の排ガスとボイラ２に供給される空気とを熱交換する熱交換器１３とを備えている。投入装置１１の構成については限定しないが、例えば、粉末状のアルカリ吸収剤を圧縮空気と共に煙道５に投入するものを使用することができる。また、ボイラ２に供給される空気が流通する空気ライン１８が設けられている。空気ライン１８は、その一端がボイラ２に接続されるとともにその他端には送風機１９が設けられ、かつ、熱交換器１３を通過するように構成されている。 (Embodiment 1)
<Configuration of Exhaust Gas Treatment Apparatus According to Embodiment 1 of the Present Disclosure>
As shown in FIG. 1, the plant 1 includes a boiler 2 that is a combustion device, an exhaust gas treatment device 3 according to Embodiment 1 of the present disclosure, and a chimney 4. The exhaust gas treatment device 3 discharges from the boiler 2 It is intended to treat the exhaust gas that is produced. The flue gas treatment device 3 includes a charging device 11 for charging a powdered alkali absorbent, such as powdered calcium carbonate, into a flue 5 through which the flue gas flows, and bringing the flue gas containing the alkali absorbent into contact with the absorbent. and a heat exchanger 13 for exchanging heat between the exhaust gas before being desulfurized in the wet desulfurization device 12 and the air supplied to the boiler 2 . Although the configuration of the injection device 11 is not limited, for example, it is possible to use a device that injects a powdered alkali absorbent into the flue 5 together with compressed air. Further, an air line 18 through which air supplied to the boiler 2 flows is provided. The air line 18 has one end connected to the boiler 2 , the other end provided with a blower 19 , and configured to pass through the heat exchanger 13 .
　排ガス処理装置３は、必須の構成ではないが、排ガスを脱硝する脱硝装置１４と、脱硝装置１４から流出した排ガスとボイラ２に供給される空気とを熱交換する熱交換器１５と、湿式脱硫装置１２において脱硫される前の排ガスからばいじん等を除去する乾式の除塵装置１６（例えば、乾式電気集塵機又はバグフィルター等）と、湿式脱硫装置１２において脱硫された排ガスから固形物質を除去する除塵装置１７とのうちの少なくとも１つをさらに備えることもできる。除塵装置１７は除塵装置１６と異なり、乾式又は湿式いずれの構成の除塵装置を使用することができる。乾式の除塵装置１７としては、例えばバグフィルターを使用することができ、湿式の除塵装置１７としては、例えば湿式電気集塵機を使用することができる。熱交換器１５が設けられる場合には、空気ライン１８は熱交換器１３だけではなく熱交換器１５も通過するように構成される。 The exhaust gas treatment device 3 is not an essential component, but includes a denitrification device 14 for denitrifying the exhaust gas, a heat exchanger 15 for exchanging heat between the exhaust gas flowing out of the denitrification device 14 and the air supplied to the boiler 2, and wet desulfurization. A dry dust remover 16 (e.g., a dry electrostatic precipitator or bag filter) that removes soot and dust from exhaust gas before it is desulfurized in the device 12, and a dust remover that removes solid substances from the exhaust gas desulfurized in the wet desulfurizer 12. 17. Unlike the dust remover 16, the dust remover 17 can use either a dry dust remover or a wet dust remover. As the dry dust remover 17, for example, a bag filter can be used, and as the wet dust remover 17, for example, a wet electrostatic precipitator can be used. If heat exchanger 15 is provided, air line 18 is arranged to pass through heat exchanger 15 as well as heat exchanger 13 .
　図２は、除塵装置１７が湿式電気集塵機である場合の構成の一例を示している。尚、除塵装置１７が湿式電気集塵機であるとしても、図２の構成の湿式電気集塵機に限定するものではなく、図２に示される構成は、湿式電気集塵機の一例に過ぎない。除塵装置１７は、煙道５に連通する筐体２１を備え、筐体２１の内部には、１つ又は複数の電極２２と、ｐＨを調整するためのアルカリ薬剤（例えば苛性ソーダ）を含んだ洗浄液を電極２２に噴きかける１つ又は複数のノズル２３と、電極２２に噴きかけられた洗浄液を再びノズル２３に戻すように洗浄液を循環させる循環ライン２４とを備えている。洗浄液を循環させるために、循環ライン２４にポンプ２５等が設けられる。 FIG. 2 shows an example of the configuration when the dust remover 17 is a wet-type electrostatic precipitator. Even if the dust remover 17 is a wet electrostatic precipitator, it is not limited to the wet electrostatic precipitator having the structure shown in FIG. 2, and the structure shown in FIG. 2 is merely an example of the wet electrostatic precipitator. The dust remover 17 includes a housing 21 communicating with the flue 5. Inside the housing 21, one or a plurality of electrodes 22 and a cleaning liquid containing an alkaline chemical (for example, caustic soda) for adjusting pH are contained. and a circulation line 24 for circulating the cleaning liquid so as to return the cleaning liquid sprayed onto the electrode 22 to the nozzles 23 again. A pump 25 or the like is provided in the circulation line 24 to circulate the cleaning liquid.
　必須の構成ではないが、循環ライン２４の異なる２つの位置Ｐ１，Ｐ２間を連通する分岐ライン２６を循環ライン２４に設け、分岐ライン２６に分離装置２７を設けてもよい。分離装置２７は、洗浄液に含まれる固形物質を洗浄液から分離するためのものであり、例えば任意の粒径以上の固形物質を濾過するフィルタであってもよい。さらに、分離装置２７で分離された固形物質を含むスラリーを保留するバッファータンク２８を設け、バッファータンク２８と湿式脱硫装置１２とを繋ぐライン２９を介して湿式脱硫装置１２にスラリーを供給するように構成してもよい。バッファータンク２８には、保留するスラリーを攪拌して、固形物質が堆積させないための撹拌機が設けられている。 Although not an essential configuration, the circulation line 24 may be provided with a branch line 26 that communicates between two different positions P 1 and P 2 of the circulation line 24 , and the branch line 26 may be provided with a separator 27 . The separation device 27 is for separating solid substances contained in the cleaning liquid from the cleaning liquid, and may be, for example, a filter for filtering solid substances having a particle size larger than an arbitrary size. Furthermore, a buffer tank 28 is provided to hold the slurry containing the solid matter separated by the separation device 27, and the slurry is supplied to the wet desulfurization device 12 via a line 29 connecting the buffer tank 28 and the wet desulfurization device 12. may be configured. The buffer tank 28 is provided with an agitator for agitating the slurry to be retained so as not to deposit solid matter.
＜本開示の実施形態１に係る排ガス処理装置の動作＞
　次に、本開示の実施形態１に係る排ガス処理装置３について説明する。図１に示されるように、ボイラ２から排出された排ガスは、煙道５を流通し、排ガス処理装置３によって処理され、煙突４を介して大気中に放出される。排ガス処理装置３が脱硝装置１４を備えている場合には、脱硝装置１４において、排ガスから窒素酸化物が除去（脱硝）される。排ガス処理装置３が熱交換器１５を備えている場合には、熱交換器１５において、排ガスは、空気ライン１８を流通する空気と熱交換することにより冷却される。排ガス処理装置３が除塵装置１６を備えている場合には、除塵装置１６において、排ガスからばいじん等が除去される。 <Operation of exhaust gas treatment apparatus according to Embodiment 1 of the present disclosure>
Next, the exhaust gas treatment device 3 according to Embodiment 1 of the present disclosure will be described. As shown in FIG. 1, exhaust gas discharged from a boiler 2 flows through a flue 5, is treated by an exhaust gas treatment device 3, and is released into the atmosphere via a chimney 4. As shown in FIG. When the exhaust gas treatment device 3 is provided with the denitration device 14 , nitrogen oxides are removed (denitrified) from the exhaust gas in the denitration device 14 . When the exhaust gas treatment device 3 includes the heat exchanger 15 , the exhaust gas is cooled in the heat exchanger 15 by exchanging heat with the air flowing through the air line 18 . When the exhaust gas treatment device 3 is provided with the dust remover 16, the dust remover 16 removes soot and dust from the exhaust gas.
　排ガス処理装置３において、投入装置１１から煙道５にアルカリ吸収剤として粉末状の炭酸カルシウムが投入されると、粉末状の炭酸カルシウムは、煙道５を流通する排ガスと混合される。粉末状の炭酸カルシウムを含んだ排ガスは、熱交換器１３において、送風機１９に昇圧されて空気ライン１８を流通する空気と熱交換することで冷却される。排ガスの温度がＳＯ３の露点よりも高ければ、ＳＯ３はガスとして排ガス中に存在するが、排ガスが冷却されてＳＯ３の露点以下になると、ＳＯ３が凝縮する。ＳＯ３が凝縮する際に、ＳＯ３は炭酸カルシウムに取り込まれる。すなわち、排ガス中からＳＯ３が除去される。 In the flue gas treatment device 3 , when powdered calcium carbonate is fed from the feeding device 11 into the flue 5 as an alkali absorbent, the powdered calcium carbonate is mixed with the flue gas flowing through the flue 5 . In the heat exchanger 13, the exhaust gas containing powdered calcium carbonate is pressurized by the blower 19 and is cooled by exchanging heat with the air flowing through the air line 18. If the temperature of the exhaust gas is higher than the dew point of SO3 , SO3 exists as a gas in the exhaust gas , but when the exhaust gas is cooled to below the dew point of SO3 , SO3 condenses. As SO 3 condenses, SO 3 is incorporated into calcium carbonate. That is, SO 3 is removed from the exhaust gas.
　一方、熱交換器１３において排ガスと熱交換することで加熱された空気はボイラ２に供給される。排ガス処理装置３が熱交換器１５を備えている場合には、空気は、熱交換器１５において排ガスと熱交換することでさらに加熱されて、ボイラ２に供給される。このようにして、熱交換器１３において熱交換器１３及び１５において加熱された空気がボイラ２に供給されることにより、ボイラ２の運転効率が向上するので、プラント１全体の運転効率が向上する。 On the other hand, the air heated by exchanging heat with the exhaust gas in the heat exchanger 13 is supplied to the boiler 2 . When the exhaust gas treatment device 3 is provided with the heat exchanger 15 , the air is further heated by exchanging heat with the exhaust gas in the heat exchanger 15 and supplied to the boiler 2 . In this way, the air heated in the heat exchangers 13 and 15 in the heat exchanger 13 is supplied to the boiler 2, so that the operation efficiency of the boiler 2 is improved, so that the operation efficiency of the plant 1 as a whole is improved. .
　熱交換器１３において冷却された排ガスは湿式脱硫装置１２に流入する。湿式脱硫装置１２において排ガスは、吸収液（例えば、炭酸カルシウム水溶液等）と気液接触することで、排ガス中の二酸化硫黄（ＳＯ２）ガス及びＳＯ３ガスが除去される（脱硫される）。また、排ガスに含まれる粉末状の炭酸カルシウムも、その大部分が吸収液に取り込まれることにより、排ガスから除去される。排ガス処理装置３が除塵装置１７を備えていない場合、湿式脱硫装置１２から流出した排ガスは、煙突４を介して大気中に放出される。 The exhaust gas cooled in the heat exchanger 13 flows into the wet desulfurization device 12 . In the wet desulfurization device 12, the exhaust gas is brought into gas-liquid contact with an absorption liquid (for example, an aqueous solution of calcium carbonate), whereby sulfur dioxide (SO 2 ) gas and SO 3 gas in the exhaust gas are removed (desulfurized). Moreover, the powdery calcium carbonate contained in the exhaust gas is also removed from the exhaust gas by being mostly taken into the absorbing liquid. If the exhaust gas treatment device 3 does not have the dust removal device 17, the exhaust gas that has flowed out of the wet desulfurization device 12 is released into the atmosphere through the chimney 4.
　排ガス処理装置３が除塵装置１７としての湿式電気集塵機を備えている場合、図２に示されるように、湿式脱硫装置１２から流出した排ガスが筐体２１の内部に流入すると、排ガス中の固形物質（主に、排ガス中に残存する粉末状の炭酸カルシウム）が静電気力によって電極２２に付着する。これにより、湿式脱硫装置１２において除去しきれなかった固形物質も除塵装置１７において排ガスから除去される。筐体２１から流出した排ガスは、煙突４（図１参照）を介して大気中に放出される。 In the case where the exhaust gas treatment device 3 is equipped with a wet electrostatic precipitator as the dust removal device 17, as shown in FIG. (Mainly powdery calcium carbonate remaining in the exhaust gas) adheres to the electrode 22 due to electrostatic force. As a result, solid substances that have not been removed by the wet desulfurization device 12 are also removed from the exhaust gas by the dust removal device 17 . Exhaust gas that has flowed out of the housing 21 is released into the atmosphere through the chimney 4 (see FIG. 1).
　排ガスに含まれるＳＯ３の濃度が高い場合、排ガスに投入される粉末状の炭酸カルシウムが多くなるので、湿式脱硫装置１２からＳＯ３ガス及び炭酸カルシウムの後逸量が多くなる。しかし、湿式脱硫装置１２の下流に除塵装置１７を設けることにより、除塵装置１７において、湿式脱硫装置１２から後逸したＳＯ３ガス及び炭酸カルシウムを除去できるので、ＳＯ３の濃度の高い排ガスの処理が可能となる。 When the concentration of SO 3 contained in the exhaust gas is high, a large amount of powdered calcium carbonate is introduced into the exhaust gas, so that a large amount of SO 3 gas and calcium carbonate escapes from the wet desulfurization apparatus 12 . However, by providing the dust remover 17 downstream of the wet desulfurization device 12, the SO 3 gas and calcium carbonate that have escaped from the wet desulfurization device 12 can be removed in the dust remover 17, so that exhaust gas with a high concentration of SO 3 can be treated. It becomes possible.
　除塵装置１７において、ポンプ２５を起動すると、循環ライン２４を流通する洗浄液がノズル２３から電極２２に噴きかけられることにより、電極２２に付着した固形物質は電極２２から洗い流されて洗浄液に取り込まれる。洗浄液は、筐体２１から流出して循環ライン２４を流通する。洗浄液は、ポンプ２５によって再びノズル２３に供給されて、電極２２に噴きかけられる。 In the dust remover 17, when the pump 25 is activated, the cleaning liquid flowing through the circulation line 24 is sprayed from the nozzle 23 onto the electrode 22, so that the solid matter adhering to the electrode 22 is washed away from the electrode 22 and incorporated into the cleaning liquid. The cleaning liquid flows out from the housing 21 and circulates through the circulation line 24 . The cleaning liquid is again supplied to the nozzle 23 by the pump 25 and sprayed onto the electrode 22 .
　循環ライン２４に分岐ライン２６及び分離装置２７が設けられている場合は、上記洗浄動作中に、循環ライン２４を流通する洗浄液の一部が分岐ライン２６を流れ、分離装置２７に流入する。分離装置２７において、洗浄液は高濃度の固形物質を含むスラリーと低濃度の固形物を含むスラリーとに分離される。洗浄液中の固形物質濃度が高いと、ノズル２３や循環ライン２４が閉塞するおそれがある。しかし、分離装置２７が設けられていれば、分離装置２７において洗浄液中の固形物質が除去されて固形物質濃度が低下するので、ノズル２３や循環ライン２４が閉塞するおそれを低減することができる。 When the circulation line 24 is provided with the branch line 26 and the separation device 27, part of the cleaning liquid flowing through the circulation line 24 flows through the branch line 26 and flows into the separation device 27 during the cleaning operation. In the separation device 27, the washing liquid is separated into a slurry containing a high concentration of solid matter and a slurry containing a low concentration of solid matter. If the solid matter concentration in the cleaning liquid is high, the nozzle 23 and the circulation line 24 may be clogged. However, if the separation device 27 is provided, the solid substances in the cleaning liquid are removed by the separation device 27 and the solid substance concentration is lowered, so that the possibility of clogging the nozzle 23 or the circulation line 24 can be reduced.
　分離装置２７にて分離された低濃度の固形物質を含むスラリーは、循環ライン２４を流通する洗浄液として再利用される。また、分離装置２７にて分離された高濃度の固形物質を含むスラリーは、湿式脱硫装置１２で使用される吸収液に含まれる炭酸カルシウムを多く含んでいるため、ライン２９を介して湿式脱硫装置１２に供給することで、吸収液の一部として再利用することができる。 The slurry containing low-concentration solid substances separated by the separation device 27 is reused as a cleaning liquid that flows through the circulation line 24 . In addition, since the slurry containing the high-concentration solid matter separated by the separation device 27 contains a large amount of calcium carbonate contained in the absorbent used in the wet desulfurization device 12, it passes through the line 29 to the wet desulfurization device. 12, it can be reused as part of the absorption liquid.
　湿式脱硫装置１２で除去しきれなかったＳＯ２やＳＯ３は、下流の除塵装置１７にて除去されるため、上記洗浄動作によって循環される洗浄液は酸性を示し、設備の腐食を発生させるおそれがある。この対策として、ポンプ２５よりも上流側において循環ライン２４に循環液タンク４１を設け、例えばアルカリ薬剤として苛性ソーダを循環液タンク４１に投入しｐＨ調整することが一般的であるが、薬剤使用により運転コストが高くなる課題がある。しかし、湿式脱硫装置１２から後逸した排ガス中に含まれる粉末状の炭酸カルシウムが、下流の除塵装置１７にて除去され循環水中に溶け込むことで、苛性ソーダを投入せずにｐＨ低下を防ぐ事ができ、アルカリ薬剤（例えば苛性ソーダ）の消費量削減となり、コスト増加をさらに抑制できる。 Since the SO 2 and SO 3 that have not been removed by the wet desulfurization device 12 are removed by the downstream dust removal device 17, the washing liquid circulated by the washing operation exhibits acidity, which may cause corrosion of the equipment. be. As a countermeasure against this, it is common to provide a circulating liquid tank 41 in the circulating line 24 upstream of the pump 25, for example, to introduce caustic soda as an alkaline chemical into the circulating liquid tank 41 to adjust the pH. There is a problem of high cost. However, the powdery calcium carbonate contained in the exhaust gas that has escaped from the wet desulfurization device 12 is removed by the downstream dust removal device 17 and dissolved in the circulating water, so that the pH can be prevented from decreasing without adding caustic soda. , the consumption of alkali chemicals (for example, caustic soda) can be reduced, and the cost increase can be further suppressed.
　このように、本開示の実施形態１に係る排ガス処理装置３では、湿式脱硫装置１２において脱硫される前の排ガスと熱交換することにより加熱された空気がボイラ２に供給され、これによりボイラ２の運転効率が向上するので、ボイラ２及び排ガス処理装置３を含むプラント１全体の運転効率が向上する。この運転効率の向上が高濃度ＳＯ３を含む排ガス処理装置の設置に基づくコスト増加を抑制し、プラント全体の経済性を向上させた排ガス処理が可能となる。 As described above, in the exhaust gas treatment apparatus 3 according to the first embodiment of the present disclosure, the air heated by exchanging heat with the exhaust gas before being desulfurized in the wet desulfurization apparatus 12 is supplied to the boiler 2, whereby the boiler 2 , the operating efficiency of the entire plant 1 including the boiler 2 and the exhaust gas treatment device 3 is improved. This improvement in operating efficiency suppresses an increase in costs due to the installation of an exhaust gas treatment apparatus containing high concentrations of SO 3 , and enables exhaust gas treatment with improved economic efficiency of the entire plant.
（実施形態２）
　次に、実施形態２に係る排ガス処理装置について説明する。実施形態１では、ボイラ２に流入する空気と排ガス処理装置３に流入する排ガスとを熱交換させており、ボイラ２及び排ガス処理装置３の各種性能を維持するためには、安定した運転制御を実施する必要が有る。そこで、実施形態２に係る排ガス処理装置は、実施形態１に対して、熱交換器１３における空気の加熱運転制御を追加したものである。尚、実施形態２において、実施形態１の構成要件と同じものは同じ参照符号を付し、その詳細な説明は省略する。 (Embodiment 2)
Next, an exhaust gas treatment apparatus according to Embodiment 2 will be described. In the first embodiment, the air flowing into the boiler 2 and the exhaust gas flowing into the exhaust gas treatment device 3 are heat-exchanged. need to implement. Therefore, in the exhaust gas treatment apparatus according to the second embodiment, air heating operation control in the heat exchanger 13 is added to the first embodiment. In the second embodiment, the same reference numerals are given to the same components as those of the first embodiment, and detailed description thereof will be omitted.
＜本開示の実施形態２に係る排ガス処理装置の構成＞
　図３に示されるように、本開示の実施形態２に係る排ガス処理装置３では、空気ライン１８に、熱交換器１３をバイパスするバイパスライン３１が設けられ、バイパスライン３１には、バイパスライン３１を流通する空気の流量を調整する調整装置３２（例えば流量調整ダンパ）が設けられている。熱交換器１３を流出した排ガスの温度を検出する温度センサ３３（第１温度検出装置）を煙道５に設け、温度センサ３３による検出値に基づいて調整装置３２を制御（例えば、流量調整ダンパの開度を制御）するようにしてもよい。ここで、熱交換器１３から流出した排ガスの温度計測値にばらつきが大きい場合など正しい値を継続して検出することが困難な場合は、温度センサ３３は、熱交換器１３に流入する排ガスの温度計測値や、熱交換器１３から流出する空気の温度計測値を用いて、調整装置３２を制御してもよい。 <Configuration of exhaust gas treatment apparatus according to Embodiment 2 of the present disclosure>
As shown in FIG. 3, in the exhaust gas treatment apparatus 3 according to Embodiment 2 of the present disclosure, the air line 18 is provided with a bypass line 31 that bypasses the heat exchanger 13, and the bypass line 31 is provided with a bypass line 31 An adjusting device 32 (eg, a flow rate adjusting damper) is provided for adjusting the flow rate of the air flowing through. A temperature sensor 33 (first temperature detection device) that detects the temperature of the exhaust gas that has flowed out of the heat exchanger 13 is provided in the flue 5, and the adjustment device 32 is controlled based on the value detected by the temperature sensor 33 (for example, a flow rate adjustment damper may be controlled). Here, when it is difficult to continuously detect a correct value, such as when there is a large variation in the temperature measurement value of the exhaust gas flowing out of the heat exchanger 13, the temperature sensor 33 detects the temperature of the exhaust gas flowing into the heat exchanger 13. The temperature measurement value or the temperature measurement value of the air flowing out of the heat exchanger 13 may be used to control the adjustment device 32 .
　また、調整装置３２よりも下流側でバイパスライン３１を流通する空気を加熱する加熱装置３４を設けてもよい。加熱装置３４の構成は限定しないが、図３には、加熱装置３４の一例としてスチームエアヒータ３４ａが描かれており、スチームエアヒータ３４ａには、スチームエアヒータ３４ａに蒸気を供給する蒸気供給ライン３５が接続され、蒸気供給ライン３５には、蒸気供給ライン３５を流れる蒸気の流量を調整する蒸気供給量調整バルブ３６が設けられている。さらに、熱交換器１５を流出した排ガスの温度を検出する温度センサ３７（第２温度検出装置）を煙道５に設け、温度センサ３７による検出値に基づいて蒸気供給量調整バルブ３６の開度を制御するようにしてもよい。ここで、熱交換器１５から流出した排ガスの温度計測値にばらつきが大きい場合など正しい値を継続して検出することが困難な場合は、温度センサ３７は、熱交換器１５に流入する排ガスの温度計測値や、除塵装置１６を流出する排ガスの温度計測値や、熱交換器１５から流出する空気の温度計測値を用いて、蒸気供給量調整バルブ３６の開度を制御してもよい。その他の構成は実施形態１と同じである。 Further, a heating device 34 that heats the air flowing through the bypass line 31 may be provided downstream of the adjustment device 32 . Although the configuration of the heating device 34 is not limited, FIG. 3 shows a steam air heater 34a as an example of the heating device 34. A steam supply line 35 for supplying steam to the steam air heater 34a is connected to the steam air heater 34a. The steam supply line 35 is provided with a steam supply amount adjustment valve 36 for adjusting the flow rate of steam flowing through the steam supply line 35 . Furthermore, a temperature sensor 37 (second temperature detection device) for detecting the temperature of the exhaust gas flowing out of the heat exchanger 15 is provided in the flue 5, and the opening degree of the steam supply amount adjustment valve 36 is determined based on the value detected by the temperature sensor 37. may be controlled. Here, when it is difficult to continuously detect a correct value, such as when there is a large variation in the temperature measurement value of the exhaust gas flowing out of the heat exchanger 15, the temperature sensor 37 detects the temperature of the exhaust gas flowing into the heat exchanger 15. The opening degree of the steam supply amount adjustment valve 36 may be controlled using the temperature measurement value, the temperature measurement value of the exhaust gas flowing out of the dust remover 16, or the temperature measurement value of the air flowing out of the heat exchanger 15. Other configurations are the same as those of the first embodiment.
＜本開示の実施形態２に係る排ガス処理装置の動作＞
　次に、本開示の実施形態２に係る排ガス処理装置３について説明する。実施形態２において、ボイラ２から排出された排ガスが排ガス処理装置３によって処理される動作は実施形態１と同じである。実施形態２では、ボイラ２へ供給される空気が熱交換器１３において加熱される動作が実施形態１と異なる。そこで、以下では、ボイラ２へ供給される空気が熱交換器１３において加熱される動作について詳細に説明する。 <Operation of exhaust gas treatment apparatus according to Embodiment 2 of the present disclosure>
Next, the exhaust gas treatment device 3 according to Embodiment 2 of the present disclosure will be described. In the second embodiment, the operation of treating the exhaust gas discharged from the boiler 2 by the exhaust gas treatment device 3 is the same as in the first embodiment. The second embodiment differs from the first embodiment in the operation of heating the air supplied to the boiler 2 in the heat exchanger 13 . Therefore, the operation of heating the air supplied to the boiler 2 in the heat exchanger 13 will be described in detail below.
　実施形態１では、熱交換器１３で加熱された空気がボイラ２に供給されることからボイラ２の運転効率が向上するが、ボイラ２に供給される空気の温度が高ければいいというものではなく、ボイラ２の運転状況に応じて空気の適切な温度が存在する。また、熱交換器１３において必要以上に空気を加熱し過ぎれば、その逆に排ガスが冷却され過ぎることになり、熱交換器１５が設置されている場合については、熱交換器１５に流入する空気の温度が低過ぎれば、熱交換器１５から流出する排ガスが冷却され過ぎることになり、熱交換器１５以降の排ガス処理装置の動作に悪影響が生じる可能性も否定できない。さらに、大気温度が大きく変動する条件下では、送風機１９が吸引する空気の温度変化が及ぼす熱交換器１５への影響を制御する必要がある。 In Embodiment 1, since the air heated by the heat exchanger 13 is supplied to the boiler 2, the operation efficiency of the boiler 2 is improved. , there is a suitable temperature of the air depending on the operating conditions of the boiler 2 . On the other hand, if the air is heated more than necessary in the heat exchanger 13, the exhaust gas will be cooled too much. If the temperature of is too low, the exhaust gas flowing out of the heat exchanger 15 will be cooled too much, and it cannot be denied that the operation of the exhaust gas treatment apparatus after the heat exchanger 15 will be adversely affected. Furthermore, under conditions where the atmospheric temperature fluctuates greatly, it is necessary to control the influence of the temperature change of the air sucked by the blower 19 on the heat exchanger 15 .
　これに対し、実施形態２では、熱交換器１３に供給される空気の一部をバイパスライン３１に流すことにより、熱交換器１３に供給される空気の流量を低下させることができる。バイパスライン３１を流れる空気の流量は調整装置３２で調整可能であり、言い換えると、熱交換器１３に供給される空気の流量を調整装置３２によって調整可能である。このように、熱交換器１３に供給される空気の供給量を調整できることから、ボイラ２に供給される空気の温度を調整できるので、ボイラ２の運転状態に適した空気をボイラ２に供給することができる。また、熱交換器１５が設置されている場合、熱交換器１５以降の排ガス処理装置の動作に適した排ガス温度を維持することができる。 On the other hand, in the second embodiment, by allowing part of the air supplied to the heat exchanger 13 to flow through the bypass line 31, the flow rate of the air supplied to the heat exchanger 13 can be reduced. The flow rate of the air flowing through the bypass line 31 can be adjusted by the adjusting device 32 , in other words, the adjusting device 32 can adjust the flow rate of the air supplied to the heat exchanger 13 . Since the amount of air supplied to the heat exchanger 13 can be adjusted in this way, the temperature of the air supplied to the boiler 2 can be adjusted. be able to. Moreover, when the heat exchanger 15 is installed, the exhaust gas temperature suitable for the operation of the exhaust gas treatment apparatus after the heat exchanger 15 can be maintained.
　熱交換器１３を流出した排ガスの温度を検出する温度センサ３３が設けられている場合には、温度センサ３３による検出値に基づいて調整装置３２を制御し、熱交換器１３に供給される空気の供給量を調整することができる。このように、熱交換器１３において空気と熱交換された排ガスの温度に基づいて、熱交換器１３に供給される空気の供給量を調整できることから、ボイラ２に供給される空気の温度を調整できるので、空気の温度調整の精度が向上し、ボイラ２の運転状態にさらに適した空気をボイラ２に供給することができる。また、熱交換器１５が設置されている場合、熱交換器１５以降の排ガス処理装置の動作に適した排ガス温度を維持することができる。 When a temperature sensor 33 for detecting the temperature of the exhaust gas that has flowed out of the heat exchanger 13 is provided, the adjustment device 32 is controlled based on the value detected by the temperature sensor 33, and the air supplied to the heat exchanger 13 can be adjusted. In this way, the amount of air supplied to the heat exchanger 13 can be adjusted based on the temperature of the exhaust gas heat-exchanged with the air in the heat exchanger 13, so the temperature of the air supplied to the boiler 2 can be adjusted. Therefore, the accuracy of air temperature adjustment is improved, and air more suitable for the operating state of the boiler 2 can be supplied to the boiler 2 . Moreover, when the heat exchanger 15 is installed, the exhaust gas temperature suitable for the operation of the exhaust gas treatment apparatus after the heat exchanger 15 can be maintained.
　バイパスライン３１を流通する空気を加熱する加熱装置３４が設けられていれば、上述の動作によってボイラ２に供給される空気の温度を調整しても空気の温度がボイラ２の運転状況に応じた適切な温度にまで上昇しない場合に、加熱装置３４によってバイパスライン３１を流通する空気を加熱することにより、ボイラ２に供給される空気の温度をボイラ２の運転状況に応じた適切な温度に調整することができる。加熱装置３４がスチームエアヒータ３４ａの場合、蒸気供給量調整バルブ３６の開度を制御することにより、スチームエアヒータ３４ａに供給される蒸気の流量を調整することにより、ボイラ２に供給される空気の温度調整を行うことができる。また、熱交換器１５が設置されている場合、熱交換器１５以降の排ガス処理装置の動作に適した排ガス温度を維持することができる。 If the heating device 34 for heating the air flowing through the bypass line 31 is provided, even if the temperature of the air supplied to the boiler 2 is adjusted by the operation described above, the temperature of the air can be adjusted according to the operating conditions of the boiler 2. When the temperature does not rise to an appropriate temperature, the air flowing through the bypass line 31 is heated by the heating device 34 to adjust the temperature of the air supplied to the boiler 2 to an appropriate temperature according to the operating conditions of the boiler 2. can do. When the heating device 34 is a steam air heater 34a, the temperature of the air supplied to the boiler 2 is adjusted by controlling the opening degree of the steam supply amount adjustment valve 36 to adjust the flow rate of the steam supplied to the steam air heater 34a. Adjustments can be made. Moreover, when the heat exchanger 15 is installed, the exhaust gas temperature suitable for the operation of the exhaust gas treatment apparatus after the heat exchanger 15 can be maintained.
　熱交換器１５を流出した排ガスの温度を検出する温度センサ３７が設けられている場合には、温度センサ３７による検出値に基づいて蒸気供給量調整バルブ３６の開度を制御することにより、加熱装置３４は空気の加熱を調整することができる。これにより、ボイラ２に供給される空気の温度をさらに適切に制御することができる。また、熱交換器１５が設置されている場合、熱交換器１５以降の排ガス処理装置の動作に適した排ガス温度を維持することができる。 When a temperature sensor 37 for detecting the temperature of the exhaust gas flowing out of the heat exchanger 15 is provided, heating is performed by controlling the opening of the steam supply amount adjustment valve 36 based on the value detected by the temperature sensor 37. Device 34 can regulate the heating of the air. Thereby, the temperature of the air supplied to the boiler 2 can be controlled more appropriately. Moreover, when the heat exchanger 15 is installed, the exhaust gas temperature suitable for the operation of the exhaust gas treatment apparatus after the heat exchanger 15 can be maintained.
　上記各実施形態に記載の内容は、例えば以下のように把握される。 The contents described in each of the above embodiments can be understood, for example, as follows.
［１］一の態様に係る排ガス処理装置は、
　燃焼装置（ボイラ２）から排出される排ガスを処理する排ガス処理装置（３）であって、
　前記排ガスに粉末状のアルカリ吸収剤を投入する投入装置（１１）と、
　前記アルカリ吸収剤を含んだ排ガスと吸収液とを接触させることにより前記排ガスの脱硫を行う湿式脱硫装置（１２）と、
　前記湿式脱硫装置（１２）において脱硫される前の排ガスと前記燃焼装置（２）に供給される空気とを熱交換する熱交換器（１３）と
を備える。 [1] An exhaust gas treatment device according to one aspect includes:
An exhaust gas treatment device (3) for treating exhaust gas discharged from a combustion device (boiler 2),
A charging device (11) for charging a powdery alkali absorbent into the exhaust gas;
a wet desulfurization device (12) for desulfurizing the exhaust gas by bringing the exhaust gas containing the alkali absorbent into contact with an absorbent;
A heat exchanger (13) is provided for exchanging heat between the exhaust gas before being desulfurized in the wet desulfurization device (12) and the air supplied to the combustion device (2).
　本開示の排ガス処理装置によれば、湿式脱硫装置において脱硫される前の排ガスと熱交換することにより加熱された空気が燃焼装置に供給され、これにより燃焼装置の運転効率が向上するので、燃焼装置及び排ガス処理装置を含むプラント全体の運転効率が向上する。この運転効率の向上が排ガス処理装置の設置に基づくコストの増加を抑制することにより、プラント全体の経済性を向上させた排ガス処理が可能となる。 According to the exhaust gas treatment apparatus of the present disclosure, the air heated by exchanging heat with the exhaust gas before being desulfurized in the wet desulfurization apparatus is supplied to the combustion apparatus, thereby improving the operation efficiency of the combustion apparatus. The operating efficiency of the entire plant, including the equipment and exhaust gas treatment equipment, is improved. This improvement in operating efficiency suppresses an increase in costs due to the installation of the exhaust gas treatment apparatus, thereby enabling exhaust gas treatment with improved economic efficiency of the entire plant.
［２］別の態様に係る排ガス処理装置は、［１］の排ガス処理装置であって、
　前記熱交換器（１３）に供給される前記空気の少なくとも一部が前記熱交換器（１３）をバイパスするバイパスライン（３１）と、
　前記バイパスライン（３１）を流通する空気の流量を調整する調整装置（３２）と
を備える。 [2] An exhaust gas treatment device according to another aspect is the exhaust gas treatment device of [1],
a bypass line (31) through which at least part of the air supplied to the heat exchanger (13) bypasses the heat exchanger (13);
and an adjusting device (32) for adjusting the flow rate of the air flowing through the bypass line (31).
　このような構成によれば、熱交換器に供給される空気の供給量を調整できることから、燃焼装置に供給される空気の温度を調整できるので、燃焼装置の運転状態に適した空気を燃焼装置に供給することができる。 With such a configuration, since the amount of air supplied to the heat exchanger can be adjusted, the temperature of the air supplied to the combustion device can be adjusted. can be supplied to
［３］さらに別の態様に係る排ガス処理装置は、［２］の排ガス処理装置であって、
　前記熱交換器（１３）において前記空気と熱交換された排ガスの温度を検出する第１温度検出装置（温度センサ３３）を備え、
　前記第１温度検出装置（３３）による検出値に基づいて、前記調整装置（３２）は、前記バイパスライン（３１）を流通する前記空気の流量を調整する。 [3] An exhaust gas treatment device according to still another aspect is the exhaust gas treatment device of [2],
A first temperature detection device (temperature sensor 33) that detects the temperature of the exhaust gas heat-exchanged with the air in the heat exchanger (13),
Based on the value detected by the first temperature detection device (33), the adjustment device (32) adjusts the flow rate of the air flowing through the bypass line (31).
　このような構成によれば、熱交換器において空気と熱交換された排ガスの温度に基づいて、熱交換器に供給される空気の供給量を調整できることから、燃焼装置に供給される空気の温度を調整できるので、空気の温度調整の精度が向上し、燃焼装置の運転状態にさらに適した空気を燃焼装置に供給することができる。 According to such a configuration, the amount of air supplied to the heat exchanger can be adjusted based on the temperature of the exhaust gas that has undergone heat exchange with the air in the heat exchanger. can be adjusted, the accuracy of air temperature adjustment is improved, and air more suitable for the operating conditions of the combustion device can be supplied to the combustion device.
［４］さらに別の態様に係る排ガス処理装置は、［２］または［３］のいずれかの排ガス処理装置であって、
　前記バイパスライン（３１）を流通する前記空気を加熱する加熱装置（３４）を備える。 [4] An exhaust gas treatment device according to yet another aspect is the exhaust gas treatment device of either [2] or [3],
A heating device (34) is provided for heating the air flowing through the bypass line (31).
　このような構成によれば、熱交換器で加熱された空気の温度が燃焼装置で要求される温度に満たない場合、空気をさらに加熱して、燃焼装置で要求される温度の空気を燃焼装置に供給することができる。 According to such a configuration, when the temperature of the air heated by the heat exchanger is lower than the temperature required by the combustion device, the air is further heated to obtain the air at the temperature required by the combustion device. can be supplied to
［５］さらに別の態様に係る排ガス処理装置は、［４］の排ガス処理装置であって、
　前記燃焼装置（２）から排出された前記排ガスの温度を検出する第２温度検出装置（温度センサ３７）を備え、
　前記第２温度検出装置（３７）による検出値に基づいて、前記加熱装置（３４）は前記空気の加熱を調整する。 [5] An exhaust gas treatment device according to still another aspect is the exhaust gas treatment device of [4],
A second temperature detection device (temperature sensor 37) that detects the temperature of the exhaust gas discharged from the combustion device (2),
Based on the value detected by the second temperature detection device (37), the heating device (34) adjusts the heating of the air.
　このような構成によれば、燃焼装置に供給される空気の温度をさらに適切に制御することができる。 According to such a configuration, it is possible to more appropriately control the temperature of the air supplied to the combustion device.
［６］さらに別の態様に係る排ガス処理装置は、［１］～［５］のいずれかの排ガス処理装置であって、
　前記熱交換器において、前記アルカリ吸収剤を含んだ排ガスは、ＳＯ３の露点以下の温度に冷却される。 [6] An exhaust gas treatment device according to yet another aspect is the exhaust gas treatment device according to any one of [1] to [5],
In the heat exchanger, the exhaust gas containing the alkali absorbent is cooled to a temperature below the dew point of SO3.
　このような構成によれば、熱交換器において排ガスが冷却されてＳＯ３の露点以下になると、排ガス中に存在するＳＯ３が凝縮し、ＳＯ３が凝縮する際に、ＳＯ３は炭酸カルシウムに取り込まれるので、排ガス中からＳＯ３を除去することができる。 According to such a configuration , when the exhaust gas is cooled in the heat exchanger to the dew point of SO 3 or lower , the SO 3 present in the exhaust gas is condensed. Since it is taken in, SO 3 can be removed from the exhaust gas.
［７］さらに別の態様に係る排ガス処理装置は、［１］～［６］のいずれかの排ガス処理装置であって、
　前記湿式脱硫装置（１２）において脱硫された排ガスから固形物質を除去する除塵装置（１７）を備える。 [7] An exhaust gas treatment device according to still another aspect is the exhaust gas treatment device according to any one of [1] to [6],
A dust remover (17) for removing solid substances from the exhaust gas desulfurized in the wet desulfurization device (12) is provided.
　排ガスに含まれるＳＯ３の濃度が高くなると、湿式脱硫装置にて除去しきれず後逸するＳＯ３ガスの量が増加し、また、排ガスに投入されるアルカリ吸収剤が多くなることで、湿式脱硫装置にて除去されず後逸するアルカリ吸収剤の量が増加する可能性がある。しかし、このような構成によれば、除塵装置において、湿式脱硫装置から後逸したＳＯ３ガス及びアルカリ吸収剤をさらに除去できるので、ＳＯ３の濃度の高い排ガスの処理が可能となる。 When the concentration of SO 3 contained in the exhaust gas increases, the amount of SO 3 gas that cannot be completely removed by the wet desulfurization equipment and is lost later increases. There is a possibility that the amount of the alkali absorbent that is not removed in the process and is lost later increases. However, according to such a configuration, the SO 3 gas and alkali absorbent that have escaped from the wet desulfurization device can be further removed in the dust remover, so that exhaust gas with a high concentration of SO 3 can be treated.
［８］さらに別の態様に係る排ガス処理装置は、［７］の排ガス処理装置であって、
　前記除塵装置（１７）は湿式電気集塵装置であり、
　前記湿式電気集塵装置は、
　前記固形物質を捕集する電極（２２）と、
　前記電極（２２）に洗浄液を噴きかけるノズル（２３）と、
　前記電極（２２）に噴きかけられた前記洗浄液を再び前記ノズル（２３）に戻すように前記洗浄液を循環させる循環ライン（２４）と
を備え、
　前記循環ライン（２４）は、該循環ライン（２４）の異なる２つの位置（Ｐ１，Ｐ２）間を連通する分岐ライン（２６）を備え、該分岐ライン（２６）には、前記洗浄液に含まれる前記固形物質を前記洗浄液から分離する分離装置（２７）が設けられている。 [8] An exhaust gas treatment device according to still another aspect is the exhaust gas treatment device of [7],
The dust remover (17) is a wet electrostatic precipitator,
The wet electrostatic precipitator is
an electrode (22) for collecting the solid matter;
a nozzle (23) for spraying a cleaning liquid onto the electrode (22);
a circulation line (24) for circulating the cleaning liquid so as to return the cleaning liquid sprayed on the electrode (22) to the nozzle (23),
Said circulation line (24) comprises a branch line (26) communicating between two different positions (P 1 , P 2 ) of said circulation line (24). A separation device (27) is provided for separating the contained solid matter from the washing liquid.
　除塵装置が湿式電気集塵装置の場合、洗浄液中の固形物質濃度が高いと洗浄液の循環ラインが閉塞するおそれがある。しかし、このような構成によれば、分離装置において洗浄液中の固形物質が除去されて固形物質濃度が低下するので、洗浄液の循環ラインが閉塞するおそれを低減することができる。 If the dust remover is a wet-type electrostatic precipitator, if the concentration of solid substances in the cleaning liquid is high, the cleaning liquid circulation line may be clogged. However, according to such a configuration, since solid substances in the cleaning liquid are removed in the separation device and the concentration of solid substances is lowered, it is possible to reduce the risk of blockage of the circulation line of the cleaning liquid.
［９］さらに別の態様に係る排ガス処理装置は、［８］の排ガス処理装置であって、
　前記分離装置（２７）で分離された前記固形物質を含むスラリーを保留するバッファータンク（２８）と、
　前記バッファータンク（２８）と前記湿式脱硫装置（１２）とを連通するライン（２９）と
を備え、
　前記バッファータンク（２８）内の前記スラリーは、前記ライン（２９）を介して前記吸収液として前記湿式脱硫装置（１２）に供給される。 [9] An exhaust gas treatment device according to still another aspect is the exhaust gas treatment device of [8],
a buffer tank (28) for retaining the slurry containing the solid matter separated by the separation device (27);
A line (29) communicating between the buffer tank (28) and the wet desulfurization device (12),
The slurry in the buffer tank (28) is supplied to the wet desulfurization unit (12) as the absorbent through the line (29).
　このような構成によれば、濃縮液を湿式脱硫装置の吸収液の一部として再利用することにより、湿式脱硫装置で使用されるアルカリ吸収剤の量を節約できるので、排ガス処理装置の運転コストを低減することができる。 According to such a configuration, by reusing the concentrated liquid as a part of the absorbent of the wet desulfurization device, the amount of alkali absorbent used in the wet desulfurization device can be saved, so the operating cost of the exhaust gas treatment device can be reduced.
２　ボイラ（燃焼装置）
３　排ガス処理装置
１１　投入装置
１２　湿式脱硫装置
１３　熱交換器
１７　除塵装置
２２　電極
２３　ノズル
２４　循環ライン
２６　分岐ライン
２７　分離装置
２８　バッファータンク
２９　ライン
３１　バイパスライン
３２　調整装置
３３　温度センサ（第１温度検出装置）
３４　加熱装置
３７　温度センサ（第２温度検出装置）
Ｐ１　（循環ライン上の）位置
Ｐ２　（循環ライン上の）位置 2 Boiler (combustion device)
3 Exhaust gas treatment device 11 Input device 12 Wet desulfurization device 13 Heat exchanger 17 Dust removal device 22 Electrode 23 Nozzle 24 Circulation line 26 Branch line 27 Separator 28 Buffer tank 29 Line 31 Bypass line 32 Adjustment device 33 Temperature sensor (first temperature detection Device)
34 heating device 37 temperature sensor (second temperature detection device)
P 1 position (on the circulation line) P 2 position (on the circulation line)

Claims (9)

  1. 　燃焼装置から排出される排ガスを処理する排ガス処理装置であって、
    　前記排ガスに粉末状のアルカリ吸収剤を投入する投入装置と、
    　前記アルカリ吸収剤を含んだ排ガスと吸収液とを接触させることにより前記排ガスの脱硫を行う湿式脱硫装置と、
    　前記湿式脱硫装置において脱硫される前の排ガスと前記燃焼装置に供給される空気とを熱交換する熱交換器と
    を備える排ガス処理装置。     An exhaust gas treatment device for treating exhaust gas discharged from a combustion device,
    A charging device for charging a powdery alkali absorbent into the exhaust gas;
    a wet desulfurization apparatus for desulfurizing the exhaust gas by contacting the exhaust gas containing the alkali absorbent with an absorbing liquid;
    An exhaust gas treatment apparatus comprising a heat exchanger for exchanging heat between exhaust gas before being desulfurized in the wet desulfurization apparatus and air supplied to the combustion apparatus.
  2. 　前記熱交換器に供給される前記空気の少なくとも一部が前記熱交換器をバイパスするバイパスラインと、
    　前記バイパスラインを流通する空気の流量を調整する調整装置と
    を備える、請求項１に記載の排ガス処理装置。     a bypass line through which at least part of the air supplied to the heat exchanger bypasses the heat exchanger;
    2. The exhaust gas treatment apparatus according to claim 1, further comprising an adjusting device that adjusts the flow rate of air flowing through said bypass line.
  3. 　前記熱交換器において前記空気と熱交換された排ガスの温度を検出する第１温度検出装置を備え、
    　前記第１温度検出装置による検出値に基づいて、前記調整装置は、前記バイパスラインを流通する前記空気の流量を調整する、請求項２に記載の排ガス処理装置。     A first temperature detection device for detecting the temperature of the exhaust gas heat-exchanged with the air in the heat exchanger,
    3. The exhaust gas treatment apparatus according to claim 2, wherein said adjustment device adjusts the flow rate of said air flowing through said bypass line based on the value detected by said first temperature detection device.
  4. 　前記バイパスラインを流通する前記空気を加熱する加熱装置を備える、請求項２または３に記載の排ガス処理装置。 The exhaust gas treatment apparatus according to claim 2 or 3, comprising a heating device for heating the air flowing through the bypass line.
  5. 　前記燃焼装置から排出された前記排ガスの温度を検出する第２温度検出装置を備え、
    　前記第２温度検出装置による検出値に基づいて、前記加熱装置は前記空気の加熱を調整する、請求項４に記載の排ガス処理装置。     A second temperature detection device for detecting the temperature of the exhaust gas discharged from the combustion device,
    5. The exhaust gas treatment apparatus according to claim 4, wherein said heating device adjusts heating of said air based on a value detected by said second temperature detection device.
  6. 　前記熱交換器において、前記アルカリ吸収剤を含んだ排ガスは、ＳＯ３の露点以下の温度に冷却される、請求項１～３のいずれか一項に記載の排ガス処理装置。 The exhaust gas treatment apparatus according to any one of claims 1 to 3, wherein the heat exchanger cools the exhaust gas containing the alkali absorbent to a temperature equal to or lower than the dew point of SO 3 .
  7. 　前記湿式脱硫装置において脱硫された排ガスから固形物質を除去する除塵装置を備える、請求項１～３のいずれか一項に記載の排ガス処理装置。 The exhaust gas treatment apparatus according to any one of claims 1 to 3, comprising a dust remover for removing solid substances from the exhaust gas desulfurized in the wet desulfurization apparatus.
  8. 　前記除塵装置は湿式電気集塵装置であり、
    　前記湿式電気集塵装置は、
    　前記固形物質を捕集する電極と、
    　前記電極に洗浄液を噴きかけるノズルと、
    　前記電極に噴きかけられた前記洗浄液を再び前記ノズルに戻すように前記洗浄液を循環させる循環ラインと
    を備え、
    　前記循環ラインは、該循環ラインの異なる２つの位置間を連通する分岐ラインを備え、該分岐ラインには、前記洗浄液に含まれる前記固形物質を前記洗浄液から分離する分離装置が設けられている、請求項７に記載の排ガス処理装置。     The dust remover is a wet electrostatic precipitator,
    The wet electrostatic precipitator is
    an electrode that collects the solid matter;
    a nozzle for spraying a cleaning liquid onto the electrode;
    a circulation line for circulating the cleaning liquid so that the cleaning liquid sprayed on the electrode is returned to the nozzle,
    The circulation line comprises a branch line communicating between two different positions of the circulation line, and the branch line is provided with a separation device for separating the solid matter contained in the cleaning liquid from the cleaning liquid. The exhaust gas treatment apparatus according to claim 7.
  9. 　前記分離装置で分離された前記固形物質を含むスラリーを保留するバッファータンクと、
    　前記バッファータンクと前記湿式脱硫装置とを連通するラインと
    を備え、
    　前記バッファータンク内の前記スラリーは、前記ラインを介して前記吸収液として前記湿式脱硫装置に供給される、請求項８に記載の排ガス処理装置。     a buffer tank for retaining the slurry containing the solid matter separated by the separation device;
    A line communicating between the buffer tank and the wet desulfurization device,
    9. The exhaust gas treatment apparatus according to claim 8, wherein said slurry in said buffer tank is supplied as said absorbent to said wet desulfurization apparatus through said line.
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Citations (8)

* Cited by examiner, † Cited by third party
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JPH04110020A (en) * 1990-08-30 1992-04-10 Babcock Hitachi Kk Exhaust gas purifying method
JPH07204433A (en) * 1994-01-25 1995-08-08 Babcock Hitachi Kk Exhaust purification method and purifier for the same
JPH11216387A (en) * 1998-01-30 1999-08-10 Seikow Chemical Engineering & Machinery Ltd Treatment of dust-containing exhaust gas
JP2010158604A (en) * 2009-01-06 2010-07-22 Mitsubishi Heavy Industries Mechatronics Systems Ltd Method of cleaning electrostatic precipitator and apparatus therefor
CN103041703A (en) * 2012-12-27 2013-04-17 浙江信耳科技有限公司 SCR (Selective Catalytic Reduction) flue gas denitration system for burning lignite
WO2013089035A1 (en) * 2011-12-12 2013-06-20 日本リファイン株式会社 Gas-liquid contact device, distillation device, and heat exchange device
WO2014014090A1 (en) * 2012-07-20 2014-01-23 三菱重工メカトロシステムズ株式会社 Wet-type electric dust collection device and dust removal method
JP2015230149A (en) * 2014-06-06 2015-12-21 三菱日立パワーシステムズ株式会社 Boiler system and power generation plant with the same

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04110020A (en) * 1990-08-30 1992-04-10 Babcock Hitachi Kk Exhaust gas purifying method
JPH07204433A (en) * 1994-01-25 1995-08-08 Babcock Hitachi Kk Exhaust purification method and purifier for the same
JPH11216387A (en) * 1998-01-30 1999-08-10 Seikow Chemical Engineering & Machinery Ltd Treatment of dust-containing exhaust gas
JP2010158604A (en) * 2009-01-06 2010-07-22 Mitsubishi Heavy Industries Mechatronics Systems Ltd Method of cleaning electrostatic precipitator and apparatus therefor
WO2013089035A1 (en) * 2011-12-12 2013-06-20 日本リファイン株式会社 Gas-liquid contact device, distillation device, and heat exchange device
WO2014014090A1 (en) * 2012-07-20 2014-01-23 三菱重工メカトロシステムズ株式会社 Wet-type electric dust collection device and dust removal method
CN103041703A (en) * 2012-12-27 2013-04-17 浙江信耳科技有限公司 SCR (Selective Catalytic Reduction) flue gas denitration system for burning lignite
JP2015230149A (en) * 2014-06-06 2015-12-21 三菱日立パワーシステムズ株式会社 Boiler system and power generation plant with the same

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