WO2018066079A1 - Coal-fired power generation equipment - Google Patents

Coal-fired power generation equipment Download PDF

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Publication number
WO2018066079A1
WO2018066079A1 PCT/JP2016/079531 JP2016079531W WO2018066079A1 WO 2018066079 A1 WO2018066079 A1 WO 2018066079A1 JP 2016079531 W JP2016079531 W JP 2016079531W WO 2018066079 A1 WO2018066079 A1 WO 2018066079A1
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Prior art keywords
coal
coal ash
exhaust gas
dust collector
power generation
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PCT/JP2016/079531
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French (fr)
Japanese (ja)
Inventor
英嗣 清永
健治 引野
啓一郎 盛田
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中国電力株式会社
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Priority to JP2017505669A priority Critical patent/JP6206619B1/en
Priority to PCT/JP2016/079531 priority patent/WO2018066079A1/en
Publication of WO2018066079A1 publication Critical patent/WO2018066079A1/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
    • B01D53/34—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
    • 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
    • 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
    • B03C3/019—Post-treatment of gases
    • 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
    • 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

Definitions

  • the present invention relates to a coal-fired power generation facility provided with a dust collector.
  • a coal-fired power generation facility has a desulfurization device for removing sulfur oxides.
  • a wet desulfurization apparatus is generally used.
  • desulfurization is realized by spraying a mixed liquid of limestone and water onto the exhaust gas so that the sulfur oxide contained in the exhaust gas is absorbed by the mixed liquid and then dehydrating.
  • the waste water generated in this dehydration process contains trace amounts of substances such as boron and selenium. According to the Water Pollution Control Law, etc., the emission of these trace substances must be kept below a certain level.
  • a coal-fired power plant is provided with a wastewater treatment device for treating the wastewater generated from the desulfurization device.
  • the burden on the wastewater treatment device increases, so measures are required.
  • An object of the present invention is to provide a coal-fired power generation facility capable of efficiently capturing coal ash contained in exhaust gas.
  • the present invention includes a denitration device that removes nitrogen oxides contained in exhaust gas generated by coal combustion, a dust collector that is disposed downstream of the denitration device and captures coal ash contained in exhaust gas, and the dust collection A desulfurization device that is disposed on the downstream side of the device and removes sulfur compounds contained in the exhaust gas; and the coal ash captured by the dust collector is collected, positively charged, downstream of the denitration device, and the
  • the present invention relates to a coal-fired power generation facility comprising charging circulation means for supplying the upstream side of the downstream end of the dust collector.
  • the dust collector has an upper dust collecting unit that captures the first coal ash having an average particle size exceeding a predetermined value, and the charging circulation means collects the first coal ash and charges it positively. It is preferable to supply to the downstream side of the upper dust collecting section.
  • the dust collector has a lower dust collecting portion that is disposed on the downstream side of the upper dust collecting portion and captures the second coal ash having an average particle size of less than the predetermined value, It is preferable that the second coal ash is collected, positively charged, and supplied to the upstream side of the lower dust collection unit.
  • a coal-fired power generation facility capable of efficiently capturing coal ash contained in exhaust gas.
  • FIG. 10 It is a schematic structure figure showing coal-fired power generation equipment 10 concerning one embodiment of the present invention. It is a block diagram which shows an example of the relationship between the structure near the electrostatic dust collector 90 of the coal thermal power generation equipment 10 of 1st Embodiment, and the charging circulation line 110. FIG. It is a block diagram which shows an example of the relationship between the structure of electric dust collector 90 vicinity of the coal thermal power generation equipment 10 of 2nd Embodiment, and the charging circulation line 110. FIG.
  • FIG. 1 is a schematic configuration diagram showing a coal-fired power generation facility 10 according to an embodiment of the present invention.
  • the coal-fired power generation facility 10 of the present embodiment includes a coal bunker 20, a coal feeder 25, a pulverized coal machine 30, a boiler 40, and an exhaust passage provided on the downstream side of the boiler 40.
  • the coal-fired power generation facility 10 includes a charging circulation line 110 and a charging device 112 as charging circulation means.
  • the coal bunker 20 stores coal supplied from a coal silo (not shown) by a coal transportation facility.
  • the coal feeder 25 supplies the coal supplied from the coal bunker 20 to the pulverized coal machine 30 at a predetermined supply speed.
  • a roller mill, a tube mill, a ball mill, a beater mill, an impeller mill, or the like is used as the pulverized coal machine 30.
  • the boiler 40 burns the pulverized coal supplied from the pulverized coal machine 30 together with the forcibly supplied air. In addition, combustion air is fed into the boiler 40 from a forced air blower 75. By burning pulverized coal, coal ash such as clinker ash and fly ash is generated and exhaust gas is generated.
  • the main components of coal ash are silica (SiO 2 ) 40 to 70%, alumina (Al 2 O 3 ) 20 to 40%, iron oxide (Fe 2 O 3 ), calcium (CaO), potassium (K 2 O), magnesium (MgO), sodium (Na 2 O) and the like are included in a small amount.
  • the exhaust passage 50 is disposed on the downstream side of the boiler 40 and distributes the exhaust gas generated in the boiler 40 and the generated coal ash.
  • the ventilator 240 and the chimney 250 are arranged in this order. While flowing through the exhaust passage 50, the coal ash contained in the exhaust gas is negatively charged due to frictional force or the like.
  • the denitration device 60 removes nitrogen oxides contained in exhaust gas generated by coal combustion.
  • the denitration device 60 injects ammonia gas as a reducing agent into the exhaust gas at a relatively high temperature (300 ° C. to 400 ° C.), and the action of the denitration catalyst converts nitrogen oxides in the exhaust gas into harmless nitrogen.
  • Nitrogen oxides in the exhaust gas are removed by a so-called dry ammonia catalytic reduction method that decomposes into water vapor.
  • the air preheater 70 is disposed downstream of the denitration device 60 in the exhaust passage 50.
  • the air preheater 70 exchanges heat between the exhaust gas that has passed through the denitration device 60 and the combustion air, cools the exhaust gas, and heats the combustion air.
  • the heated combustion air is supplied to the boiler 40 by the forced air blower 75.
  • the heat recovery gas heater 80 is disposed downstream of the air preheater 70 in the exhaust passage 50.
  • the exhaust gas recovered by the air preheater 70 is supplied to the heat recovery gas heater 80.
  • the heat recovery gas heater 80 further recovers heat from the exhaust gas.
  • the electrostatic precipitator 90 is disposed downstream of the denitration device 60 and captures coal ash contained in the exhaust gas. Specifically, the electrostatic precipitator 90 is disposed downstream of the heat recovery gas heater 80 in the exhaust passage 50.
  • the electric dust collector 90 is supplied with the exhaust gas heat recovered in the heat recovery gas heater 80.
  • the electric dust collector 90 is a device that collects (captures) coal ash (fly ash) in exhaust gas by applying a voltage to electrodes. Coal ash (fly ash) collected (captured) in the electric dust collector 90 is recovered by the fly ash recovery device 120 and also recovered by the charging circulation line 110.
  • the electric dust collector 90 is preferably provided in a plurality of stages.
  • the first dust collecting stage 91a as the upper dust collecting part
  • the second dust collecting stage 91b the third dust collecting stage 91c
  • the lower dust collecting part A fourth dust collection stage 91d is provided.
  • the dust collection stages 91a to 91d are arranged so that the average particle diameter of the coal ash that can be captured from the upstream side toward the downstream side becomes smaller. Therefore, the average particle diameter of the coal ash contained in the exhaust gas flowing in the vicinity of the dust collection stages 91a to 91d is from the upstream side (first dust collection stage 91a side) to the downstream side (fourth dust collection stage 91d side). Get smaller.
  • the average weight of the coal ash contained in the exhaust gas flowing in the vicinity of the dust collection stages 91a to 91d is light from the upstream side (first dust collection stage 91a side) to the downstream side (fourth dust collection stage 91d side). Become.
  • the first dust collection stage 91a captures the first coal ash having an average particle size exceeding a predetermined value (for example, 20 ⁇ m). In the present embodiment, the first dust collection stage 91a captures coal ash having an average particle size in the range of about 20 to 100 ⁇ m as the first coal ash. In addition, the fourth dust collection stage 91d captures the second coal ash having an average particle size that is lower than a predetermined value (for example, 20 ⁇ m). In the present embodiment, the fourth dust collection stage 91d captures coal ash having an average particle diameter in the range of approximately 10 to 30 ⁇ m as the second coal ash.
  • a predetermined value for example, 20 ⁇ m
  • FIG. 2 is a block diagram showing an example of the relationship between the configuration near the electrostatic precipitator 90 of the coal-fired power generation facility 10 of the first embodiment and the charging circulation means.
  • the charging circulation means includes a charging circulation line 110 and a charging device 112.
  • the charging circulation line 110 collects the coal ash captured by the electrostatic precipitator 90 and supplies the coal ash to the downstream side of the denitration device 60 and the upstream side of the downstream end of the electrostatic precipitator 90. Road.
  • the charging circulation line 110 connects the first dust collection stage 91a and the fourth dust collection stage 91d of the electric dust collector 90. Further, the charging circulation line 110 collects, for example, the first coal ash from the first dust collection stage 91a and supplies it to the downstream side of the first dust collection stage 91a (in the vicinity of the fourth dust collection stage 91d in FIG. 2) ( Recirculate).
  • the first coal ash is positively charged by the charging device 112 on the way through the charging circulation line 110.
  • the charging device 112 includes a discharge electrode (not shown). A corona discharge is generated by applying a high voltage to the discharge electrode. The coal ash is positively charged in the vicinity of the discharge electrode of the charging device 112 and is supplied to the downstream side of the first dust collection stage 91a.
  • the induction ventilator 210 is disposed on the downstream side of the electric dust collector 90 in the exhaust passage 50.
  • the induction ventilator 210 takes in the exhaust gas flowing through the downstream side of the electrostatic precipitator 90 from the primary side and sends it out to the secondary side.
  • the desulfurization device 220 is arranged on the downstream side of the electrostatic precipitator 90 and removes sulfur compounds contained in the exhaust gas. Specifically, the desulfurization device 220 is disposed on the downstream side of the induction fan 210 in the exhaust passage 50.
  • the desulfurization apparatus 220 is supplied with exhaust gas sent from the induction fan 210.
  • the desulfurization apparatus 220 sprays a mixed liquid of limestone and water on the exhaust gas, thereby absorbing the sulfur oxide contained in the exhaust gas into the mixed liquid to generate a desulfurized gypsum slurry, and dehydrating the desulfurized gypsum slurry. This produces desulfurized gypsum.
  • the desulfurized gypsum generated in the desulfurization apparatus 220 is recovered by a desulfurization gypsum recovery apparatus 222 connected to this apparatus.
  • the reheating gas heater 230 is disposed downstream of the desulfurization device 220 in the exhaust passage 50.
  • the reheat gas heater 230 is supplied with exhaust gas from which sulfur oxides have been removed in the desulfurization apparatus 220.
  • the reheating gas heater 230 heats the exhaust gas.
  • the heat recovery gas heater 80 and the reheating gas heater 230 circulate between the exhaust gas flowing between the air preheater 70 and the electrostatic precipitator 90 and between the desulfurization device 220 and the desulfurization ventilator 240 in the exhaust passage 50. You may comprise as a gas heater which heat-exchanges with the waste gas to perform.
  • the desulfurization ventilator 240 is disposed downstream of the reheating gas heater 230 in the exhaust passage 50.
  • the desulfurization ventilator 240 takes in the exhaust gas heated in the reheating gas heater 230 from the primary side and sends it to the secondary side.
  • the chimney 250 is disposed downstream of the desulfurization ventilator 240 in the exhaust passage 50. Exhaust gas heated by the reheating gas heater 230 is introduced into the chimney 250. The chimney 250 discharges exhaust gas.
  • the coal-fired power generation facility 10 is disposed on the downstream side of the denitration device 60 that removes nitrogen oxides contained in the exhaust gas and the denitration device 60, and the exhaust gas
  • An electrostatic precipitator 90 that captures coal ash contained in the coal
  • a desulfurizer 220 that is disposed downstream of the electrostatic precipitator 90 and removes sulfur compounds contained in the exhaust gas
  • a charging circulation line 110 that collects ash, charges positively, and supplies the ash to the downstream side of the denitration device 60 and the upstream side of the downstream end portion of the electrostatic precipitator 90.
  • the coal ash supplied (recirculated) to the upstream side of the downstream side of the denitration device 60 and the downstream side of the electrostatic precipitator 90 is positively charged by the charging device 112.
  • the coal ash contained in the exhaust gas is negatively charged due to frictional force or the like while flowing through the exhaust passage 50.
  • a Coulomb force is generated between the positively charged coal ash and the negatively charged coal ash. . Therefore, on the downstream side of the denitration device 60, the positively charged coal ash adsorbs fine coal ash (negatively charged coal ash) contained in the exhaust gas.
  • the fine coal ash is adsorbed by the recycled coal ash and is collected again by the electrostatic precipitator 90, the fine coal ash contained in the exhaust gas can be efficiently captured.
  • the coal ash captured by the electrostatic precipitator 90 can be effectively used to capture (adsorb) the coal ash contained in the exhaust gas.
  • the electrostatic precipitator 90 has a first dust collection stage 91a that captures the first coal ash having an average particle size exceeding a predetermined value, and the charging circulation line 110 collects the first coal ash and positively It is charged and supplied to the downstream side of the first dust collection stage 91a.
  • the average particle diameter and weight of the first coal ash recovered in the first dust collection stage 91a are the average particle diameter and weight of the coal ash (for example, second coal ash) captured on the downstream side of the first dust collection stage 91a. Is larger and heavier than the first coal ash (positively charged coal ash) having a large particle size on the downstream side of the first dust collection stage 91a, and light coal ash (negatively charged coal) contained in the exhaust gas. Coulomb force is generated to adsorb ash). Thereby, the coal ash contained in the exhaust gas can be captured more efficiently.
  • FIG. 3 is a block diagram illustrating an example of a relationship between the configuration near the electrostatic precipitator 90 of the coal-fired power generation facility 10 according to the second embodiment and the charging circulation line 110.
  • the coal-fired power generation facility 10 of the second embodiment is different from the coal-fired power generation facility 10 of the first embodiment in the relationship between the configuration near the electric dust collector 90 and the charging circulation line 110.
  • the other structure is the same as that of the coal thermal power generation equipment 10 of 1st Embodiment, description is abbreviate
  • the charging circulation line 110 collects the second coal ash from, for example, the fourth dust collection stage 91d, and is upstream of the fourth dust collection stage 91d (in FIG. 3, the first dust collection stage 91a). (Recirculation) The second coal ash is positively charged by the charging device 112 on the way through the charging circulation line 110.
  • the charging device 112 includes a discharge electrode (not shown). A corona discharge is generated by applying a high voltage to the discharge electrode. The coal ash is positively charged in the vicinity of the discharge electrode of the charging device 112 and is supplied to the upstream side of the fourth dust collection stage 91d.
  • the average particle diameter and weight of the second coal ash recovered by the fourth dust collection stage 91d are upstream of the fourth dust collection stage 91d.
  • Smaller and lighter than the average particle size and weight of the captured coal ash eg, first coal ash.
  • the smaller the average particle size of coal ash the greater the number of coal ash particles per unit volume (weight). Therefore, on the upstream side of the fourth dust collection stage 91d, the second coal ash having a large number of particles (positively charged coal ash) is mixed with coal ash having a large particle size contained in the exhaust gas (negatively charged coal ash). Increases the number of contacts. Thereby, the fine coal ash contained in the exhaust gas can be captured more efficiently.
  • the electrostatic precipitator 90 is provided in four stages
  • the number of stages other than four stages may be provided.
  • the charging circulation line 110 collects coal ash from the first dust collection stage 91a (the fourth dust collection stage 91d in the second embodiment) of the electric dust collector 90, and collects the fourth dust collection of the electric dust collector 90.
  • the example which supplies (recirculates) the dust stage 91d (1st dust collection stage 91a in 2nd Embodiment) was demonstrated, it is not limited to this.
  • the charging circulation line 110 collects coal ash from the electric dust collector 90 (any one of the dust collecting stages 91a to 91d) and supplies it to the exhaust passage 50 between the denitration device 60 and the electric dust collector 90. May be.
  • the number of charging circulation lines 110 is not limited to one, and the coal-fired power generation facility 10 may include a plurality of charging circulation lines 110.
  • the direction in which the coal ash flows in the charging circulation line 110 is one direction (specifically, the direction from the first dust collection stage 91a toward the downstream side (see FIG. 2) or the upstream side from the fourth dust collection stage 91d. Is not limited to the direction (see FIG. 3)), and may be bidirectional. Further, in the charging circulation line 110, a configuration other than the charging device 112 may charge the coal ash.

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Abstract

In order to provide coal-fired power generation equipment capable of efficiently capturing fly ash included in exhaust gas, this coal-fired power generation equipment 10 comprises: a denitration device 60 that removes nitrogen oxides included in exhaust gas generated by the combustion of coal; a dust collection device 90 that is arranged downstream of the denitration device 60 and captures fly ash included in exhaust gas; a desulfurization device 220 that is arranged downstream of the dust collection device 90 and removes sulfur compounds included in the exhaust gas; and a charging and circulation means 110 that collects fly ash captured by the collection device 90, positively charges same, and supplies same to the downstream side of the denitration device 60 and upstream of a downstream end of the collection device 90.

Description

石炭火力発電設備Coal-fired power generation facility
　本発明は、集塵装置を備える石炭火力発電設備に関する。 The present invention relates to a coal-fired power generation facility provided with a dust collector.
　石炭火力発電設備では、石炭の燃焼に伴い硫黄酸化物が発生するが、大気汚染防止法等により、硫黄酸化物の排出は一定水準以下に抑えることが必要となっている。そこで石炭火力発電設備では、硫黄酸化物を除去する脱硫装置を設置している。この脱硫装置としては、湿式脱硫装置が一般的に用いられている。すなわち、排ガスに石灰石と水との混合液を吹き付けることにより、排ガスに含有されている硫黄酸化物を混合液に吸収させ、その後脱水処理することで脱硫を実現している。 In coal-fired power generation facilities, sulfur oxides are generated when coal is burned, but it is necessary to keep the emission of sulfur oxides below a certain level by the Air Pollution Control Law. Therefore, a coal-fired power generation facility has a desulfurization device for removing sulfur oxides. As this desulfurization apparatus, a wet desulfurization apparatus is generally used. In other words, desulfurization is realized by spraying a mixed liquid of limestone and water onto the exhaust gas so that the sulfur oxide contained in the exhaust gas is absorbed by the mixed liquid and then dehydrating.
　この脱水処理において発生する排水には、微量のホウ素、セレン等の微量物質が含まれる。水質汚濁防止法等により、これらの微量物質の排出は一定水準以下に抑える事が必要となっている。そこで、石炭火力発電所では、脱硫装置から発生する排水を処理する排水処理装置が設けられている。しかし、排水中に微量物質が多量に含まれると、排水処理装置の負担が大きくなるため対策が必要となる。 The waste water generated in this dehydration process contains trace amounts of substances such as boron and selenium. According to the Water Pollution Control Law, etc., the emission of these trace substances must be kept below a certain level. In view of this, a coal-fired power plant is provided with a wastewater treatment device for treating the wastewater generated from the desulfurization device. However, if a large amount of trace substances are contained in the wastewater, the burden on the wastewater treatment device increases, so measures are required.
　そのため、排ガスに含まれる微量物質を集塵装置で除去（補足）することで排水処理装置の負担を軽減している。また、集塵装置を設けたうえで、石炭の燃焼残渣（例えば、集塵装置で捕捉される石炭灰）を、燃焼中又は燃焼前の石炭の段階で添加する技術が提案されている（例えば、特許文献１）。石炭と石炭灰とが混焼される結果として、石炭灰が微小な粒子を物理的に取り込むため、石炭灰の粒径は相対的に大きくなり、集塵装置において集塵効率が向上する。また、特許文献１の技術によれば、集塵装置によって捕捉した石炭灰を、集塵効率の向上のために有効活用できる。 Therefore, the burden of waste water treatment equipment is reduced by removing (supplementing) trace substances contained in exhaust gas with a dust collector. In addition, a technique for adding a combustion residue of coal (for example, coal ash captured by the dust collector) at the stage of coal during combustion or before combustion has been proposed after providing a dust collector (for example, Patent Document 1). As a result of co-combustion of coal and coal ash, the coal ash physically takes in fine particles, so that the particle size of the coal ash becomes relatively large and the dust collection efficiency is improved in the dust collector. Moreover, according to the technique of patent document 1, the coal ash captured by the dust collector can be effectively used for improving the dust collection efficiency.
特開２００７－３３３３４６号公報JP 2007-333346 A
　しかしながら、特許文献１に記載された技術によれば、集塵装置によって捕捉した石炭灰を、ボイラに戻さなければならないため、石炭灰がボイラに戻されることでボイラ及びその下流側に配置される構成に影響を与える可能性がある。例えば、石炭灰をボイラに戻すことにより、ボイラの燃焼効率に影響を与える可能性がある。そのため、効率のよい手段で排ガスに含まれる石炭灰を捕捉する必要がある。 However, according to the technique described in Patent Document 1, since the coal ash captured by the dust collector must be returned to the boiler, the coal ash is returned to the boiler and disposed on the boiler and its downstream side. May affect configuration. For example, returning coal ash to the boiler may affect the combustion efficiency of the boiler. Therefore, it is necessary to capture coal ash contained in the exhaust gas by an efficient means.
　本発明は、排ガスに含まれる石炭灰を効率よく捕捉できる石炭火力発電設備を提供することを目的とする。 An object of the present invention is to provide a coal-fired power generation facility capable of efficiently capturing coal ash contained in exhaust gas.
　本発明は、石炭の燃焼によって生じる排ガスに含まれる窒素酸化物を除去する脱硝装置と、前記脱硝装置の下流側に配置され、排ガスに含まれる石炭灰を捕捉する集塵装置と、前記集塵装置の下流側に配置され、排ガスに含まれる硫黄化合物を除去する脱硫装置と、前記集塵装置が捕捉した前記石炭灰を、回収し、正に帯電させ、前記脱硝装置の下流側、且つ前記集塵装置の下流側の端部よりも上流側に供給する帯電循環手段と、を備える石炭火力発電設備に関する。 The present invention includes a denitration device that removes nitrogen oxides contained in exhaust gas generated by coal combustion, a dust collector that is disposed downstream of the denitration device and captures coal ash contained in exhaust gas, and the dust collection A desulfurization device that is disposed on the downstream side of the device and removes sulfur compounds contained in the exhaust gas; and the coal ash captured by the dust collector is collected, positively charged, downstream of the denitration device, and the The present invention relates to a coal-fired power generation facility comprising charging circulation means for supplying the upstream side of the downstream end of the dust collector.
　また、前記集塵装置は、平均粒径が所定値を上回る第１石炭灰を捕捉する上段集塵部を有し、前記帯電循環手段は、前記第１石炭灰を回収し、正に帯電させ、前記上段集塵部の下流側に供給することが好ましい。 In addition, the dust collector has an upper dust collecting unit that captures the first coal ash having an average particle size exceeding a predetermined value, and the charging circulation means collects the first coal ash and charges it positively. It is preferable to supply to the downstream side of the upper dust collecting section.
　また、前記集塵装置は、前記上段集塵部の下流側に配置され、平均粒径が前記所定値を下回る第２石炭灰を捕捉する下段集塵部を有し、前記帯電循環手段は、前記第２石炭灰を回収し、正に帯電させ、前記下段集塵部の上流側に供給することが好ましい。 In addition, the dust collector has a lower dust collecting portion that is disposed on the downstream side of the upper dust collecting portion and captures the second coal ash having an average particle size of less than the predetermined value, It is preferable that the second coal ash is collected, positively charged, and supplied to the upstream side of the lower dust collection unit.
　本発明によれば、排ガスに含まれる石炭灰を効率よく捕捉できる石炭火力発電設備が提供される。 According to the present invention, a coal-fired power generation facility capable of efficiently capturing coal ash contained in exhaust gas is provided.
本発明の一実施形態に係る石炭火力発電設備１０を示す概略構成図である。It is a schematic structure figure showing coal-fired power generation equipment 10 concerning one embodiment of the present invention. 第１実施形態の石炭火力発電設備１０の電気集塵装置９０付近の構成と、帯電循環ライン１１０との関係の一例を示すブロック図である。It is a block diagram which shows an example of the relationship between the structure near the electrostatic dust collector 90 of the coal thermal power generation equipment 10 of 1st Embodiment, and the charging circulation line 110. FIG. 第２実施形態の石炭火力発電設備１０の電気集塵装置９０付近の構成と、帯電循環ライン１１０との関係の一例を示すブロック図である。It is a block diagram which shows an example of the relationship between the structure of electric dust collector 90 vicinity of the coal thermal power generation equipment 10 of 2nd Embodiment, and the charging circulation line 110. FIG.
　以下、本発明の実施形態について、図面を参照しながら説明する。
［第１実施形態］
　図１は、本発明の一実施形態に係る石炭火力発電設備１０を示す概略構成図である。本実施形態の石炭火力発電設備１０は、図１に示すように、石炭バンカ２０と、給炭機２５と、微粉炭機３０と、ボイラ４０と、ボイラ４０の下流側に設けられた排気通路５０と、この排気通路５０に設けられた脱硝装置６０、空気予熱器７０、熱回収用ガスヒータ８０、集塵装置としての電気集塵装置９０、誘引通風機２１０、脱硫装置２２０、再加熱用ガスヒータ２３０、脱硫通風機２４０、及び煙突２５０と、を備える。また、石炭火力発電設備１０は、帯電循環手段としての帯電循環ライン１１０及び帯電装置１１２を備える。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a schematic configuration diagram showing a coal-fired power generation facility 10 according to an embodiment of the present invention. As shown in FIG. 1, the coal-fired power generation facility 10 of the present embodiment includes a coal bunker 20, a coal feeder 25, a pulverized coal machine 30, a boiler 40, and an exhaust passage provided on the downstream side of the boiler 40. 50, a denitration device 60 provided in the exhaust passage 50, an air preheater 70, a heat recovery gas heater 80, an electric dust collection device 90 as a dust collection device, an induction fan 210, a desulfurization device 220, and a reheating gas heater 230, a desulfurization ventilator 240, and a chimney 250. The coal-fired power generation facility 10 includes a charging circulation line 110 and a charging device 112 as charging circulation means.
　石炭バンカ２０は、石炭サイロ（図示しない）から運炭設備によって供給された石炭を貯蔵する。給炭機２５は、石炭バンカ２０から供給された石炭を所定の供給スピードで微粉炭機３０に供給する。
　微粉炭機３０としては、ローラミル、チューブミル、ボールミル、ビータミル、インペラーミル等が用いられる。 The coal bunker 20 stores coal supplied from a coal silo (not shown) by a coal transportation facility. The coal feeder 25 supplies the coal supplied from the coal bunker 20 to the pulverized coal machine 30 at a predetermined supply speed.
As the pulverized coal machine 30, a roller mill, a tube mill, a ball mill, a beater mill, an impeller mill, or the like is used.
　ボイラ４０は、微粉炭機３０から供給された微粉炭を、強制的に供給された空気と共に燃焼する。またボイラ４０には、押込通風機７５から燃焼用空気が送り込まれる。微粉炭を燃焼することによりクリンカアッシュ及びフライアッシュ等の石炭灰が生成されると共に、排ガスが発生する。
　石炭灰の主成分は、シリカ（ＳｉＯ２）４０～７０％、アルミナ（Ａｌ２Ｏ３）２０～４０％であり、他に酸化鉄（Ｆｅ２Ｏ３）、カルシウム（ＣａＯ）、カリウム（Ｋ２Ｏ）、マグネシウム（ＭｇＯ）、ナトリウム（Ｎａ２Ｏ）等が少量含まれる。 The boiler 40 burns the pulverized coal supplied from the pulverized coal machine 30 together with the forcibly supplied air. In addition, combustion air is fed into the boiler 40 from a forced air blower 75. By burning pulverized coal, coal ash such as clinker ash and fly ash is generated and exhaust gas is generated.
The main components of coal ash are silica (SiO 2 ) 40 to 70%, alumina (Al 2 O 3 ) 20 to 40%, iron oxide (Fe 2 O 3 ), calcium (CaO), potassium (K 2 O), magnesium (MgO), sodium (Na 2 O) and the like are included in a small amount.
　排気通路５０は、ボイラ４０の下流側に配置され、ボイラ４０で発生した排ガス及び生成された石炭灰を流通させる。この排気通路５０には、上述のように、脱硝装置６０、空気予熱器７０、熱回収用ガスヒータ８０、電気集塵装置９０、誘引通風機２１０、脱硫装置２２０と、再加熱用ガスヒータ２３０、脱硫通風機２４０、及び煙突２５０がこの順で配置される。
　排気通路５０を流通する間に、排ガスに含まれる石炭灰は、摩擦力等により負に帯電する。 The exhaust passage 50 is disposed on the downstream side of the boiler 40 and distributes the exhaust gas generated in the boiler 40 and the generated coal ash. In the exhaust passage 50, as described above, the denitration device 60, the air preheater 70, the heat recovery gas heater 80, the electric dust collector 90, the induction fan 210, the desulfurization device 220, the reheating gas heater 230, the desulfurization The ventilator 240 and the chimney 250 are arranged in this order.
While flowing through the exhaust passage 50, the coal ash contained in the exhaust gas is negatively charged due to frictional force or the like.
　脱硝装置６０は、石炭の燃焼によって生じる排ガスに含まれる窒素酸化物を除去する。本実施形態では、脱硝装置６０は、比較的高温（３００℃～４００℃）の排ガス中に還元剤としてアンモニアガスを注入し、脱硝触媒との作用により排ガス中の窒素酸化物を無害な窒素と水蒸気に分解する、いわゆる乾式アンモニア接触還元法により排ガス中の窒素酸化物を除去する。 The denitration device 60 removes nitrogen oxides contained in exhaust gas generated by coal combustion. In the present embodiment, the denitration device 60 injects ammonia gas as a reducing agent into the exhaust gas at a relatively high temperature (300 ° C. to 400 ° C.), and the action of the denitration catalyst converts nitrogen oxides in the exhaust gas into harmless nitrogen. Nitrogen oxides in the exhaust gas are removed by a so-called dry ammonia catalytic reduction method that decomposes into water vapor.
　空気予熱器７０は、排気通路５０における脱硝装置６０の下流側に配置される。空気予熱器７０は、脱硝装置６０を通過した排ガスと燃焼用空気とを熱交換させ、排ガスを冷却すると共に、燃焼用空気を加熱する。加熱された燃焼用空気は、押込通風機７５によりボイラ４０に供給される。 The air preheater 70 is disposed downstream of the denitration device 60 in the exhaust passage 50. The air preheater 70 exchanges heat between the exhaust gas that has passed through the denitration device 60 and the combustion air, cools the exhaust gas, and heats the combustion air. The heated combustion air is supplied to the boiler 40 by the forced air blower 75.
　熱回収用ガスヒータ８０は、排気通路５０における空気予熱器７０の下流側に配置される。熱回収用ガスヒータ８０には、空気予熱器７０において熱回収された排ガスが供給される。熱回収用ガスヒータ８０は、排ガスから更に熱回収する。 The heat recovery gas heater 80 is disposed downstream of the air preheater 70 in the exhaust passage 50. The exhaust gas recovered by the air preheater 70 is supplied to the heat recovery gas heater 80. The heat recovery gas heater 80 further recovers heat from the exhaust gas.
　電気集塵装置９０は、脱硝装置６０の下流側に配置され、排ガスに含まれる石炭灰を捕捉する。詳細には、電気集塵装置９０は、排気通路５０における熱回収用ガスヒータ８０の下流側に配置される。電気集塵装置９０には、熱回収用ガスヒータ８０において熱回収された排ガスが供給される。電気集塵装置９０は、電極に電圧を印加することによって排ガス中の石炭灰（フライアッシュ）を収集（捕捉）する装置である。電気集塵装置９０において収集（捕捉）される石炭灰（フライアッシュ）は、フライアッシュ回収装置１２０に回収される他、帯電循環ライン１１０によって回収される。電気集塵装置９０は、複数段設けられることが好ましい。 The electrostatic precipitator 90 is disposed downstream of the denitration device 60 and captures coal ash contained in the exhaust gas. Specifically, the electrostatic precipitator 90 is disposed downstream of the heat recovery gas heater 80 in the exhaust passage 50. The electric dust collector 90 is supplied with the exhaust gas heat recovered in the heat recovery gas heater 80. The electric dust collector 90 is a device that collects (captures) coal ash (fly ash) in exhaust gas by applying a voltage to electrodes. Coal ash (fly ash) collected (captured) in the electric dust collector 90 is recovered by the fly ash recovery device 120 and also recovered by the charging circulation line 110. The electric dust collector 90 is preferably provided in a plurality of stages.
　本実施形態においては、電気集塵装置９０は４段設けられる（図２を参照）。具体的には、上流側から下流側に向けて、上段集塵部としての第１集塵段９１ａと、第２集塵段９１ｂと、第３集塵段９１ｃと、下段集塵部としての第４集塵段９１ｄとが設けられる。集塵段９１ａ～ｄは上流側から下流側に向けて捕捉できる石炭灰の平均粒径が小さくなるように配置される。そのため、集塵段９１ａ～ｄ付近を流通する排ガスに含まれる石炭灰の平均粒径は、上流側（第１集塵段９１ａ側）から下流側（第４集塵段９１ｄ側）に向けて小さくなる。また、集塵段９１ａ～ｄ付近を流通する排ガスに含まれる石炭灰の平均重量は、上流側（第１集塵段９１ａ側）から下流側（第４集塵段９１ｄ側）に向けて軽くなる。 In this embodiment, four stages of electrostatic precipitators 90 are provided (see FIG. 2). Specifically, from the upstream side toward the downstream side, the first dust collecting stage 91a as the upper dust collecting part, the second dust collecting stage 91b, the third dust collecting stage 91c, and the lower dust collecting part A fourth dust collection stage 91d is provided. The dust collection stages 91a to 91d are arranged so that the average particle diameter of the coal ash that can be captured from the upstream side toward the downstream side becomes smaller. Therefore, the average particle diameter of the coal ash contained in the exhaust gas flowing in the vicinity of the dust collection stages 91a to 91d is from the upstream side (first dust collection stage 91a side) to the downstream side (fourth dust collection stage 91d side). Get smaller. Further, the average weight of the coal ash contained in the exhaust gas flowing in the vicinity of the dust collection stages 91a to 91d is light from the upstream side (first dust collection stage 91a side) to the downstream side (fourth dust collection stage 91d side). Become.
　第１集塵段９１ａは、平均粒径が所定値（例えば、２０μｍ）を上回る第１石炭灰を捕捉する。本実施形態においては、第１集塵段９１ａは、平均粒径がおよそ２０～１００μｍの範囲の石炭灰を第１石炭灰として捕捉する。
　また、第４集塵段９１ｄは、平均粒径が所定値（例えば、２０μｍ）を下回る第２石炭灰を捕捉する。本実施形態においては、第４集塵段９１ｄは、平均粒径がおよそ１０～３０μｍの範囲の石炭灰を第２石炭灰として捕捉する。 The first dust collection stage 91a captures the first coal ash having an average particle size exceeding a predetermined value (for example, 20 μm). In the present embodiment, the first dust collection stage 91a captures coal ash having an average particle size in the range of about 20 to 100 μm as the first coal ash.
In addition, the fourth dust collection stage 91d captures the second coal ash having an average particle size that is lower than a predetermined value (for example, 20 μm). In the present embodiment, the fourth dust collection stage 91d captures coal ash having an average particle diameter in the range of approximately 10 to 30 μm as the second coal ash.
　図２を用いて、石炭火力発電設備１０の電気集塵装置９０付近の構成と、帯電循環手段との関係の一例について説明する。図２は、第１実施形態の石炭火力発電設備１０の電気集塵装置９０付近の構成と、帯電循環手段との関係の一例を示すブロック図である。帯電循環手段は、帯電循環ライン１１０と、帯電装置１１２と、を備える。 An example of the relationship between the configuration near the electrostatic precipitator 90 of the coal-fired power generation facility 10 and the charging circulation means will be described with reference to FIG. FIG. 2 is a block diagram showing an example of the relationship between the configuration near the electrostatic precipitator 90 of the coal-fired power generation facility 10 of the first embodiment and the charging circulation means. The charging circulation means includes a charging circulation line 110 and a charging device 112.
　帯電循環ライン１１０は、電気集塵装置９０が捕捉した石炭灰を回収し、脱硝装置６０の下流側、且つ電気集塵装置９０の下流側の端部よりも上流側に供給する石炭灰の流路である。本実施形態においては、帯電循環ライン１１０は、電気集塵装置９０の第１集塵段９１ａと、第４集塵段９１ｄとを接続する。また、帯電循環ライン１１０は、例えば第１集塵段９１ａから第１石炭灰を回収し、第１集塵段９１ａの下流側（図２においては、第４集塵段９１ｄ付近）に供給（再循環）する。第１石炭灰は、帯電循環ライン１１０を流通する途中で帯電装置１１２によって正に帯電される。 The charging circulation line 110 collects the coal ash captured by the electrostatic precipitator 90 and supplies the coal ash to the downstream side of the denitration device 60 and the upstream side of the downstream end of the electrostatic precipitator 90. Road. In the present embodiment, the charging circulation line 110 connects the first dust collection stage 91a and the fourth dust collection stage 91d of the electric dust collector 90. Further, the charging circulation line 110 collects, for example, the first coal ash from the first dust collection stage 91a and supplies it to the downstream side of the first dust collection stage 91a (in the vicinity of the fourth dust collection stage 91d in FIG. 2) ( Recirculate). The first coal ash is positively charged by the charging device 112 on the way through the charging circulation line 110.
　帯電装置１１２は、図示しない放電電極を備える。この放電電極に高電圧を印加することで、コロナ放電が発生する。石炭灰は、帯電装置１１２の放電電極付近で正に帯電され、第１集塵段９１ａの下流側に供給される。 The charging device 112 includes a discharge electrode (not shown). A corona discharge is generated by applying a high voltage to the discharge electrode. The coal ash is positively charged in the vicinity of the discharge electrode of the charging device 112 and is supplied to the downstream side of the first dust collection stage 91a.
　誘引通風機２１０は、排気通路５０における電気集塵装置９０の下流側に配置される。誘引通風機２１０は、電気集塵装置９０の下流側を流通する排ガスを、一次側から取り込んで二次側に送り出す。 The induction ventilator 210 is disposed on the downstream side of the electric dust collector 90 in the exhaust passage 50. The induction ventilator 210 takes in the exhaust gas flowing through the downstream side of the electrostatic precipitator 90 from the primary side and sends it out to the secondary side.
　脱硫装置２２０は、電気集塵装置９０の下流側に配置され、排ガスに含まれる硫黄化合物を除去する。詳細には、脱硫装置２２０は、排気通路５０における誘引通風機２１０の下流側に配置される。脱硫装置２２０には、誘引通風機２１０から送り出された排ガスが供給される。脱硫装置２２０は、排ガスに石灰石と水との混合液を吹き付けることにより、排ガスに含有されている硫黄酸化物を混合液に吸収させて脱硫石膏スラリーを生成させ、この脱硫石膏スラリーを脱水処理することで脱硫石膏を生成する。脱硫装置２２０において生成された脱硫石膏は、この装置に接続された脱硫石膏回収装置２２２に回収される。 The desulfurization device 220 is arranged on the downstream side of the electrostatic precipitator 90 and removes sulfur compounds contained in the exhaust gas. Specifically, the desulfurization device 220 is disposed on the downstream side of the induction fan 210 in the exhaust passage 50. The desulfurization apparatus 220 is supplied with exhaust gas sent from the induction fan 210. The desulfurization apparatus 220 sprays a mixed liquid of limestone and water on the exhaust gas, thereby absorbing the sulfur oxide contained in the exhaust gas into the mixed liquid to generate a desulfurized gypsum slurry, and dehydrating the desulfurized gypsum slurry. This produces desulfurized gypsum. The desulfurized gypsum generated in the desulfurization apparatus 220 is recovered by a desulfurization gypsum recovery apparatus 222 connected to this apparatus.
　再加熱用ガスヒータ２３０は、排気通路５０における脱硫装置２２０の下流側に配置される。再加熱用ガスヒータ２３０には、脱硫装置２２０において硫黄酸化物が除去された排ガスが供給される。再加熱用ガスヒータ２３０は、排ガスを加熱する。熱回収用ガスヒータ８０及び再加熱用ガスヒータ２３０は、排気通路５０における、空気予熱器７０と電気集塵装置９０との間を流通する排ガスと、脱硫装置２２０と脱硫通風機２４０との間を流通する排ガスと、の間で熱交換を行うガスヒータとして構成してもよい。 The reheating gas heater 230 is disposed downstream of the desulfurization device 220 in the exhaust passage 50. The reheat gas heater 230 is supplied with exhaust gas from which sulfur oxides have been removed in the desulfurization apparatus 220. The reheating gas heater 230 heats the exhaust gas. The heat recovery gas heater 80 and the reheating gas heater 230 circulate between the exhaust gas flowing between the air preheater 70 and the electrostatic precipitator 90 and between the desulfurization device 220 and the desulfurization ventilator 240 in the exhaust passage 50. You may comprise as a gas heater which heat-exchanges with the waste gas to perform.
　脱硫通風機２４０は、排気通路５０における再加熱用ガスヒータ２３０の下流側に配置される。脱硫通風機２４０は、再加熱用ガスヒータ２３０において加熱された排ガスを一次側から取り込んで二次側に送り出す。 The desulfurization ventilator 240 is disposed downstream of the reheating gas heater 230 in the exhaust passage 50. The desulfurization ventilator 240 takes in the exhaust gas heated in the reheating gas heater 230 from the primary side and sends it to the secondary side.
　煙突２５０は、排気通路５０における脱硫通風機２４０の下流側に配置される。煙突２５０には、再加熱用ガスヒータ２３０で加熱された排ガスが導入される。煙突２５０は、排ガスを排出する。 The chimney 250 is disposed downstream of the desulfurization ventilator 240 in the exhaust passage 50. Exhaust gas heated by the reheating gas heater 230 is introduced into the chimney 250. The chimney 250 discharges exhaust gas.
　以上、説明したように構成された第１実施形態によれば、石炭火力発電設備１０は、排ガスに含まれる窒素酸化物を除去する脱硝装置６０と、脱硝装置６０の下流側に配置され、排ガスに含まれる石炭灰を捕捉する電気集塵装置９０と、電気集塵装置９０の下流側に配置され、排ガスに含まれる硫黄化合物を除去する脱硫装置２２０と、電気集塵装置９０が捕捉した石炭灰を回収し、正に帯電させ、脱硝装置６０の下流側、且つ電気集塵装置９０の下流側の端部よりも上流側に供給する帯電循環ライン１１０と、を備える。
　脱硝装置６０の下流側、且つ電気集塵装置９０の下流側の端部よりも上流側に供給される（再循環される）石炭灰は、帯電装置１１２によって正に帯電される。一方で、排ガスに含まれる石炭灰は、排気通路５０を流通する間に摩擦力等により負に帯電する。このように、再循環される石炭灰と、排ガスに含まれる石炭灰とが反対の電荷をもつことにより、正に帯電した石炭灰と負に帯電した石炭灰との間にクーロン力が発生する。そのため、脱硝装置６０の下流側において、正に帯電した石炭灰が、排ガスに含まれる微小な石炭灰（負に帯電した石炭灰）を吸着する。これにより、微小な石炭灰が再循環された石炭灰に吸着された状態で、再度電気集塵装置９０において回収されるため、排ガスに含まれる微小な石炭灰を効率よく捕捉できる。
　また、電気集塵装置９０によって捕捉した石炭灰を、排ガスに含まれる石炭灰を捕捉（吸着）するために有効活用することもできる。 As described above, according to the first embodiment configured as described above, the coal-fired power generation facility 10 is disposed on the downstream side of the denitration device 60 that removes nitrogen oxides contained in the exhaust gas and the denitration device 60, and the exhaust gas An electrostatic precipitator 90 that captures coal ash contained in the coal, a desulfurizer 220 that is disposed downstream of the electrostatic precipitator 90 and removes sulfur compounds contained in the exhaust gas, and coal captured by the electrostatic precipitator 90 A charging circulation line 110 that collects ash, charges positively, and supplies the ash to the downstream side of the denitration device 60 and the upstream side of the downstream end portion of the electrostatic precipitator 90.
The coal ash supplied (recirculated) to the upstream side of the downstream side of the denitration device 60 and the downstream side of the electrostatic precipitator 90 is positively charged by the charging device 112. On the other hand, the coal ash contained in the exhaust gas is negatively charged due to frictional force or the like while flowing through the exhaust passage 50. In this way, when the recycled coal ash and the coal ash contained in the exhaust gas have opposite charges, a Coulomb force is generated between the positively charged coal ash and the negatively charged coal ash. . Therefore, on the downstream side of the denitration device 60, the positively charged coal ash adsorbs fine coal ash (negatively charged coal ash) contained in the exhaust gas. Thereby, since the fine coal ash is adsorbed by the recycled coal ash and is collected again by the electrostatic precipitator 90, the fine coal ash contained in the exhaust gas can be efficiently captured.
In addition, the coal ash captured by the electrostatic precipitator 90 can be effectively used to capture (adsorb) the coal ash contained in the exhaust gas.
　また、電気集塵装置９０は、平均粒径が所定値を上回る第１石炭灰を捕捉する第１集塵段９１ａを有し、帯電循環ライン１１０は、第１石炭灰を回収し、正に帯電させ、第１集塵段９１ａの下流側に供給する。
　第１集塵段９１ａで回収される第１石炭灰の平均粒径及び重量は、第１集塵段９１ａの下流側で捕捉される石炭灰（例えば第２石炭灰）の平均粒径及び重量よりも、大きく、重いため、第１集塵段９１ａの下流側において、粒径の大きい第１石炭灰（正に帯電した石炭灰）が、排ガスに含まれる軽い石炭灰（負に帯電した石炭灰）を吸着するようにクーロン力が発生する。これにより、排ガスに含まれる石炭灰をより効率よく捕捉できる。 Further, the electrostatic precipitator 90 has a first dust collection stage 91a that captures the first coal ash having an average particle size exceeding a predetermined value, and the charging circulation line 110 collects the first coal ash and positively It is charged and supplied to the downstream side of the first dust collection stage 91a.
The average particle diameter and weight of the first coal ash recovered in the first dust collection stage 91a are the average particle diameter and weight of the coal ash (for example, second coal ash) captured on the downstream side of the first dust collection stage 91a. Is larger and heavier than the first coal ash (positively charged coal ash) having a large particle size on the downstream side of the first dust collection stage 91a, and light coal ash (negatively charged coal) contained in the exhaust gas. Coulomb force is generated to adsorb ash). Thereby, the coal ash contained in the exhaust gas can be captured more efficiently.
［第２実施形態］
　図３は、第２実施形態の石炭火力発電設備１０の電気集塵装置９０付近の構成と、帯電循環ライン１１０との関係の一例を示すブロック図である。図３に示すように、第２実施形態の石炭火力発電設備１０は、電気集塵装置９０付近の構成と、帯電循環ライン１１０との関係が、第１実施形態の石炭火力発電設備１０と異なっている。なお、その他の構成は、第１実施形態の石炭火力発電設備１０と同様なので、説明を省略する。 [Second Embodiment]
FIG. 3 is a block diagram illustrating an example of a relationship between the configuration near the electrostatic precipitator 90 of the coal-fired power generation facility 10 according to the second embodiment and the charging circulation line 110. As shown in FIG. 3, the coal-fired power generation facility 10 of the second embodiment is different from the coal-fired power generation facility 10 of the first embodiment in the relationship between the configuration near the electric dust collector 90 and the charging circulation line 110. ing. In addition, since the other structure is the same as that of the coal thermal power generation equipment 10 of 1st Embodiment, description is abbreviate | omitted.
　第２実施形態においては、帯電循環ライン１１０は、例えば第４集塵段９１ｄから第２石炭灰を回収し、第４集塵段９１ｄの上流側（図３においては、第１集塵段９１ａ付近）に供給（再循環）する。第２石炭灰は、帯電循環ライン１１０を流通する途中で帯電装置１１２によって正に帯電される。 In the second embodiment, the charging circulation line 110 collects the second coal ash from, for example, the fourth dust collection stage 91d, and is upstream of the fourth dust collection stage 91d (in FIG. 3, the first dust collection stage 91a). (Recirculation) The second coal ash is positively charged by the charging device 112 on the way through the charging circulation line 110.
　帯電装置１１２は、図示しない放電電極を備える。この放電電極に高電圧を印加することで、コロナ放電が発生する。石炭灰は、帯電装置１１２の放電電極付近で正に帯電され、第４集塵段９１ｄの上流側に供給される。 The charging device 112 includes a discharge electrode (not shown). A corona discharge is generated by applying a high voltage to the discharge electrode. The coal ash is positively charged in the vicinity of the discharge electrode of the charging device 112 and is supplied to the upstream side of the fourth dust collection stage 91d.
　以上、説明したように構成された第２実施形態によれば、第４集塵段９１ｄで回収される第２石炭灰の平均粒径及び重量は、第４集塵段９１ｄよりも上流側で捕捉される石炭灰（例えば第１石炭灰）の平均粒径及び重量よりも、小さく、軽い。一般に石炭灰の平均粒径が小さいほど、単位体積（重量）当たりの石炭灰の粒子数は多くなる。そのため、第４集塵段９１ｄの上流側において、粒子数の多い第２石炭灰（正に帯電した石炭灰）は、排ガスに含まれる粒径の大きい石炭灰（負に帯電した石炭灰）と接触する回数が多くなる。これにより、排ガスに含まれる微小な石炭灰をより効率よく捕捉できる。 As described above, according to the second embodiment configured as described above, the average particle diameter and weight of the second coal ash recovered by the fourth dust collection stage 91d are upstream of the fourth dust collection stage 91d. Smaller and lighter than the average particle size and weight of the captured coal ash (eg, first coal ash). Generally, the smaller the average particle size of coal ash, the greater the number of coal ash particles per unit volume (weight). Therefore, on the upstream side of the fourth dust collection stage 91d, the second coal ash having a large number of particles (positively charged coal ash) is mixed with coal ash having a large particle size contained in the exhaust gas (negatively charged coal ash). Increases the number of contacts. Thereby, the fine coal ash contained in the exhaust gas can be captured more efficiently.
　以上、本発明の石炭火力発電設備１０の好ましい各実施形態につき説明したが、本発明は、上述の実施形態に制限されるものではなく、適宜変更が可能である。 The preferred embodiments of the coal-fired power generation facility 10 of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and can be appropriately changed.
　例えば、電気集塵装置９０は４段設けられる例を説明したが、４段以外の段数（例えば、３段）設けられてもよい。 For example, although the example in which the electrostatic precipitator 90 is provided in four stages has been described, the number of stages other than four stages (for example, three stages) may be provided.
　また、帯電循環ライン１１０は、電気集塵装置９０の第１集塵段９１ａ（第２実施形態においては第４集塵段９１ｄ）から石炭灰を回収し、電気集塵装置９０の第４集塵段９１ｄ（第２実施形態においては第１集塵段９１ａ）に供給（再循環）する例について説明したが、これに限定されない。例えば、帯電循環ライン１１０は、電気集塵装置９０（集塵段９１ａ～ｄのいずれか）から石炭灰を回収し、脱硝装置６０と電気集塵装置９０との間の排気通路５０に供給してもよい。 Further, the charging circulation line 110 collects coal ash from the first dust collection stage 91a (the fourth dust collection stage 91d in the second embodiment) of the electric dust collector 90, and collects the fourth dust collection of the electric dust collector 90. Although the example which supplies (recirculates) the dust stage 91d (1st dust collection stage 91a in 2nd Embodiment) was demonstrated, it is not limited to this. For example, the charging circulation line 110 collects coal ash from the electric dust collector 90 (any one of the dust collecting stages 91a to 91d) and supplies it to the exhaust passage 50 between the denitration device 60 and the electric dust collector 90. May be.
　また、帯電循環ライン１１０の数は１つに限定されず、石炭火力発電設備１０は、複数の帯電循環ライン１１０を有してもよい。また、帯電循環ライン１１０における石炭灰の流通する向きは一方向（具体的には、第１集塵段９１ａから下流側に向かう方向（図２を参照）又は第４集塵段９１ｄから上流側に向かう方向（図３を参照））に限定されず、双方向であってもよい。また、帯電循環ライン１１０において、帯電装置１１２以外の構成が石炭灰を帯電させてもよい。 Further, the number of charging circulation lines 110 is not limited to one, and the coal-fired power generation facility 10 may include a plurality of charging circulation lines 110. The direction in which the coal ash flows in the charging circulation line 110 is one direction (specifically, the direction from the first dust collection stage 91a toward the downstream side (see FIG. 2) or the upstream side from the fourth dust collection stage 91d. Is not limited to the direction (see FIG. 3)), and may be bidirectional. Further, in the charging circulation line 110, a configuration other than the charging device 112 may charge the coal ash.
　１０　石炭火力発電設備
　６０　脱硝装置
　９０　電気集塵装置（集塵装置）
　９１ａ　第１集塵段（上段集塵部）
　９１ｄ　第４集塵段（下段集塵部）
　１１０　帯電循環ライン（帯電循環手段）
　２２０　脱硫装置 10 Coal-fired power generation facilities 60 Denitration equipment 90 Electric dust collector (dust collector)
91a First dust collection stage (upper dust collection part)
91d Fourth dust collection stage (lower dust collection part)
110 Charging circulation line (charging circulation means)
220 Desulfurization equipment

Claims (3)

  1. 　石炭の燃焼によって生じる排ガスに含まれる窒素酸化物を除去する脱硝装置と、
    　前記脱硝装置の下流側に配置され、排ガスに含まれる石炭灰を捕捉する集塵装置と、
    　前記集塵装置の下流側に配置され、排ガスに含まれる硫黄化合物を除去する脱硫装置と、
    　前記集塵装置が捕捉した前記石炭灰を回収し、正に帯電させ、前記脱硝装置の下流側、且つ前記集塵装置の下流側の端部よりも上流側に供給する帯電循環手段と、を備える石炭火力発電設備。     A denitration device that removes nitrogen oxides contained in exhaust gas generated by coal combustion;
    A dust collector disposed downstream of the denitration device and capturing coal ash contained in the exhaust gas;
    A desulfurization device that is disposed downstream of the dust collector and removes sulfur compounds contained in the exhaust gas;
    Charging and circulating means for collecting the coal ash captured by the dust collector, positively charging, and supplying the coal ash downstream of the denitration device and upstream of the downstream end of the dust collector; Equipped with coal-fired power generation equipment.
  2. 　前記集塵装置は、平均粒径が所定値を上回る第１石炭灰を捕捉する上段集塵部を有し、
    　前記帯電循環手段は、前記第１石炭灰を回収し、正に帯電させ、前記上段集塵部の下流側に供給する、請求項１に記載の石炭火力発電設備。     The dust collector has an upper dust collector that captures the first coal ash having an average particle size exceeding a predetermined value,
    2. The coal-fired power generation facility according to claim 1, wherein the charging circulation unit collects the first coal ash, charges it positively, and supplies the first coal ash to the downstream side of the upper dust collection unit.
  3. 　前記集塵装置は、前記上段集塵部の下流側に配置され、平均粒径が前記所定値を下回る第２石炭灰を捕捉する下段集塵部を有し、
    　前記帯電循環手段は、前記第２石炭灰を回収し、正に帯電させ、前記下段集塵部の上流側に供給する、請求項２に記載の石炭火力発電設備。     The dust collector is disposed on the downstream side of the upper dust collector, and has a lower dust collector that captures second coal ash having an average particle size below the predetermined value,
    The coal-fired power generation facility according to claim 2, wherein the charging circulation means collects the second coal ash, charges it positively, and supplies the second coal ash to the upstream side of the lower dust collecting section.
PCT/JP2016/079531 2016-10-04 2016-10-04 Coal-fired power generation equipment WO2018066079A1 (en)

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JPS6044065A (en) * 1983-08-22 1985-03-08 Mitsubishi Heavy Ind Ltd Dust collecting apparatus
JPS6342752A (en) * 1986-08-07 1988-02-23 Mitsubishi Heavy Ind Ltd Conditioning device for electrostatic precipitator
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