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WO2016067652A1 - Procédé de suppression de l'élution d'arsenic - Google Patents

Procédé de suppression de l'élution d'arsenic Download PDF

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Publication number
WO2016067652A1
WO2016067652A1 PCT/JP2015/059802 JP2015059802W WO2016067652A1 WO 2016067652 A1 WO2016067652 A1 WO 2016067652A1 JP 2015059802 W JP2015059802 W JP 2015059802W WO 2016067652 A1 WO2016067652 A1 WO 2016067652A1
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WO
WIPO (PCT)
Prior art keywords
coal
arsenic
elution
ash
combustion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2015/059802
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English (en)
Japanese (ja)
Inventor
健治 引野
啓一郎 盛田
英嗣 清永
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chugoku Electric Power Co Inc
Original Assignee
Chugoku Electric Power Co Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Chugoku Electric Power Co Inc filed Critical Chugoku Electric Power Co Inc
Priority to JP2016540072A priority Critical patent/JP6079940B2/ja
Publication of WO2016067652A1 publication Critical patent/WO2016067652A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K1/00—Preparation of lump or pulverulent fuel in readiness for delivery to combustion apparatus

Definitions

  • the present invention relates to an arsenic elution suppression method for suppressing elution of arsenic from coal combustion residue (coal ash) used as fuel in a thermal power plant that generates power by burning coal.
  • an object of the present invention is to provide a method for suppressing arsenic elution that can more stably suppress elution of arsenic from coal combustion residues.
  • the present invention mixes a plurality of types of coal including a first coal having an arsenic concentration of 2.0 ppm or more by mass and one or more other types of coal other than the first coal.
  • An arsenic elution suppression method that suppresses arsenic elution from the combustion residue of coal by burning, and the mass of the total alkaline earth metal amount in terms of oxide with respect to the total arsenic amount in the total coal after mixing
  • the present invention relates to an arsenic elution suppression method in which mixing is performed so that the ratio P 0 is 2000 or more.
  • weight ratio P 1 of the alkaline earth metal of the oxide-equivalent is less than 2000.
  • weight ratio P 2 of the total alkali earth metal of the oxide-equivalent is 2000 or more.
  • the mass ratio P 2 and [Delta] P P 2 -P 1 is the difference P 1 is 1000 or more.
  • the first coal is contained in an amount of 10% to 90%.
  • arsenic elution suppression method of the present invention arsenic elution from coal combustion residues can be suppressed more stably.
  • FIG. 1 It is a schematic block diagram of the pulverized coal combustion facility in the coal thermal power plant which shows one Embodiment of this invention. It is an enlarged view of the vicinity of the furnace in FIG.
  • FIG. 1 is a block diagram showing a pulverized coal combustion facility 1 in a coal-fired power plant to which the present invention is applied.
  • the pulverized coal combustion facility 1 includes a coal supply unit 12 that supplies coal, a pulverized coal generation unit 14 that converts the supplied coal into pulverized coal, and a pulverized coal that burns pulverized coal.
  • generated by combustion of pulverized coal are provided.
  • the coal supply unit 12 includes a coal bunker 121 that stores coal, and a coal feeder 122 that supplies the coal stored in the coal bunker 121.
  • the coal bunker 121 stores coal to be supplied to the coal feeder 122.
  • the coal bunker 121 includes, for example, a plurality of coal storage tanks that are partitioned from each other, and each of the plurality of coal storage tanks can store and manage different types of coal.
  • the coal feeder 122 continuously supplies the coal supplied from the coal bunker 121 to the coal pulverized coal machine 123.
  • this coal feeder 122 is provided with the apparatus which adjusts the supply_amount
  • a coal gate is provided at the boundary between the coal bunker 121 and the coal feeder 122, thereby preventing air from the coal feeder from flowing into the coal bunker.
  • the pulverized coal generation unit 14 includes a coal pulverized coal machine (mill) 141 that converts coal into pulverized coal capable of pulverized coal combustion, and an air supply unit 142 that supplies air to the coal pulverized coal machine 141.
  • the coal pulverized coal machine 141 pulverizes the coal supplied from the coal feeder 122 through the coal supply pipe to form fine pulverized coal, and is supplied from the pulverized coal and the air supply unit 142. Mix with fresh air. Thus, by mixing pulverized coal and air, the pulverized coal is preheated and dried to facilitate combustion. Air is blown onto the formed pulverized coal, thereby supplying the pulverized coal to the pulverized coal combustion unit 16.
  • Examples of the coal pulverized coal machine 141 include a roller mill, a tube mill, a ball mill, a beater mill, and an impeller mill.
  • the present invention is not limited to these, and any mill that is used in pulverized coal combustion may be used.
  • the pulverized coal combustion unit 16 includes a furnace 161 that combusts the pulverized coal generated by the pulverized coal generation unit 14, a heater 162 that heats the furnace 161, and an air supply unit 163 that supplies air to the furnace 161. Prepare.
  • the furnace 161 is heated by the heater 162 and combusts the pulverized coal supplied from the coal pulverized coal machine 141 via the pulverized coal pipe together with the air supplied from the air supply unit 163.
  • coal ash is produced by burning pulverized coal.
  • the coal ash generated in the furnace 161 is divided into fly ash that moves to the coal ash treatment unit 18 side as floating particles together with exhaust gas, and clinker ash that drops and accumulates at the bottom of the furnace 161 by agglomeration of a plurality of particles. Broadly divided.
  • the furnace 161 will be described in detail with reference to FIG. 2.
  • the furnace 161 has a substantially inverted U shape as a whole, and after the combustion gas moves in an inverted U shape along the arrow in the figure. Then, it is reversed again into a U-shape, and the outlet of the furnace 161 (the last of the arrows in FIG. 2) is connected to the denitration device 181 and the dust collector 182 in FIG.
  • the height of the furnace 161 is 30 m to 70 m, and the total length of the exhaust gas flow path ranges from 300 m to 1000 m.
  • a burner 161a for burning pulverized coal is disposed in the vicinity of the burner zone 161a 'in the furnace 161. Further, near the top of the U-shape in the furnace 161, a furnace upper dividing wall 161b, a final superheater 161b ′, and a first reheater 161f (all of which are heat exchange units) are arranged, and further placed horizontally from there. A primary superheater 161c (heat exchange unit) is subsequently arranged.
  • a second reheater 161f ′ is provided in parallel with the horizontal primary superheater 161c, and from the vicinity of the terminal end of the horizontal primary superheater 161c, a primary economizer 161d (heat exchange unit).
  • a secondary economizer 161e (heat exchange unit) is provided in two stages.
  • the economizer also referred to as ECO
  • the primary economizer 161d and the secondary economizer 161e are separately installed in two stages, but the present invention is not limited to such a form. That is, the furnace 161 may have only a single economizer.
  • the coal ash treatment unit 18 collects the denitration device 181 that removes nitrogen oxides in the exhaust gas discharged from the pulverized coal combustion unit 16, the dust collector 182 that removes soot (coal ash) in the exhaust gas, and the dust collector 182. And a coal ash recovery silo 183 for primarily storing the coal ash thus obtained.
  • the denitration device 181 removes nitrogen oxides in the exhaust gas. That is, ammonia gas is injected as a reducing agent into exhaust gas at a relatively high temperature (300 to 400 degrees), and nitrogen oxides in the exhaust gas are decomposed into harmless nitrogen and water vapor by the action of a denitration catalyst, so-called dry ammonia contact A reduction method is preferably used.
  • the dust collector 182 is a device that collects coal ash in the exhaust gas with an electrode.
  • the coal ash collected by the dust collector 182 is conveyed to the coal ash collection silo 183. Further, the exhaust gas from which the coal ash has been removed is discharged from the chimney after passing through a desulfurization apparatus (not shown).
  • the coal ash collection silo 183 primarily stores the coal ash collected by the dust collector 182.
  • Coal used as fuel contains silicon, aluminum, calcium, magnesium, and the like as ash in addition to carbon as a main component. Coal contains trace amounts of harmful elements such as selenium, fluorine, boron, and arsenic.
  • harmful elements such as selenium, fluorine, boron, and arsenic.
  • the various components contained in the coal vary greatly depending on the coal type. For this reason, depending on the type of coal used as fuel, the concentration of harmful elements eluted from coal ash, which is a combustion residue, increases, which may affect the environment.
  • the inventors pay attention to the fact that the content of various components varies greatly depending on the coal type of coal, and the mass ratio of the total alkaline earth metal amount in terms of oxide to the total amount of arsenic contained in the coal to be burned is predetermined. Found that the leaching of arsenic from coal ash is suppressed when it is within the range, and even when coal with a high arsenic concentration is used, this coal is mixed with other coal that satisfies the specific composition Thus, the present invention has reached the present invention that can stably suppress elution of arsenic from the combustion residue.
  • the arsenic elution suppression method of the present invention includes a first coal having an arsenic concentration of 2.0 ppm or more by mass ratio, and one or more other coals other than the first coal.
  • the present invention will be described using the pulverized coal combustion facility 1 described above.
  • the arsenic elution suppression method of the present invention includes coal supply step S10 for supplying coal, pulverized coal generation step S20 for pulverizing the supplied coal to generate pulverized coal, and burning the pulverized coal to generate coal ash.
  • the pulverized coal combustion step S30 and the coal ash treatment step S40 that collects and stores the coal ash, each of which includes the coal supply unit 12 and the pulverized coal of the pulverized coal combustion facility 1 described above, respectively. It is performed in the generation unit 14, the pulverized coal combustion unit 16, and the coal ash processing unit 18. And mixing of the multiple types of coal which is the characteristics of this invention is preferably performed in said coal supply process S10.
  • the coal stored in the coal bunker 121 is supplied to the coal pulverized coal machine 141 by the coal feeder 122.
  • P 0 total alkali in oxide equivalent
  • a plurality of types of coal are mixed and supplied so that (earth metal amount / total arsenic amount) is 2000 or more.
  • Coal mixing in the coal supply step S10 is performed by, for example, storing a plurality of types of coal including a first coal having an arsenic concentration of 2.0 ppm or more in a mass ratio in a plurality of coal storage tanks in the coal bunker 121.
  • the coal stored in the other coal storage tank is dispensed at the same timing so as to have a predetermined ratio with respect to the first coal.
  • the coals are joined together on a belt conveyor or the like and supplied to the coal pulverizer 141. Thereby, a plurality of types of coal are supplied to the coal pulverized coal machine 141 at a substantially equal ratio.
  • the first coal arsenic concentration is as high as 2.0 ppm or more in mass ratio, and conventionally, it is possible to use a coal type that has been difficult to use as fuel in a thermal power plant.
  • P 2 total alkaline earth metal in terms of oxide
  • the ratio of the first coal contained in the mixed coal is preferably 10% or more and 90% or less.
  • the coal supplied from the coal feeder 122 is pulverized by the coal pulverized coal machine 141, thereby generating pulverized coal.
  • the generated pulverized coal is supplied to the furnace 161.
  • the average particle size of the pulverized coal formed in the pulverized coal generation step may be a particle size range generally used in pulverized coal combustion, and generally 74 ⁇ m under 80 wt% or more. The degree of pulverization.
  • pulverized coal combustion process S30> the pulverized coal generated by the coal pulverized coal machine 141 is burned by the furnace 161.
  • the coal ash (fly ash) produced in this pulverized coal combustion process is usually in the form of a powder having an average particle size in the range of 1 ⁇ m to 100 ⁇ m.
  • the coal ash recovered in the coal ash recovery silo 183 through the above steps has a reduced arsenic elution amount. This is because the alkaline earth metal element contained in the coal softens the surface of the coal ash due to the high temperature in the furnace 161, and the viscous coal ash particles come into contact with arsenic and take arsenic into the coal ash. It is estimated that Moreover, in this embodiment, focusing on the alkaline earth metal content and arsenic content which differ for every charcoal type, the elution of arsenic can be stably suppressed by mixing multiple types of coal. This is considered due to the fact that the alkaline earth metal can be distributed more uniformly than when limestone or the like is added as an additive.
  • This effect can be further improved by setting the ratio of the first coal contained in the coal after mixing to 10% or more and 90% or less by mass ratio.
  • the arsenic concentration in the coal was determined by elemental analysis by ICP mass spectrometry after pretreatment.
  • the amount of alkaline earth metal in the coal was determined as the total amount of calcium oxide and magnesium oxide by determining the ash content in the coal and then analyzing the ash composition by fluorescent X-ray analysis.
  • the measurement results of the elution concentration shown below are those obtained by performing the elution operation according to Environmental Agency Notification No. 46, preparing a test solution, and measuring the concentration of arsenic in this test solution.
  • the arsenic concentration was measured by ICP mass spectrometry.
  • a vertical tubular furnace provided with a combustion tube made of zirconia having an inner diameter of 50 mm ⁇ ⁇ 1200 mmL was used as a small combustion test apparatus.
  • the coal used in the test was first put in a drying apparatus adjusted to a specified temperature (107 ° C. ⁇ 2 ° C.) in the form of pulverized coal, and continued to be dried until the loss on drying was less than 0.1% per hour. . Thereafter, the dried pulverized coal was mixed at a predetermined ratio.
  • pulverized coal mixed in a stainless steel fuel hopper disposed at the upper part of the combustion pipe was filled, and supplied to the upper part of the combustion pipe heated to 1450 ° C. by an electric screw feeder at 2 g / min for combustion.
  • the supply of pulverized coal to the combustion tube was performed together with the supply of nitrogen gas to the combustion tube, thereby preventing backfire inside the combustion tube.
  • Combustion air atmosphere
  • the coal ash produced by burning inside the combustion tube was collected by suction from the lower side surface of the combustion tube.
  • concentration of boron was measured about the collect
  • the results are shown in Table 14. In addition, a result is shown by the relative value when the elution density

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)

Abstract

L'invention concerne un procédé de suppression de l'élution d'arsenic permettant de supprimer de façon plus stable l'élution d'arsenic hors de résidu de combustion de charbon. Le procédé de suppression de l'élution d'arsenic pour la suppression de l'élution d'arsenic hors de résidu de combustion de charbon selon l'invention consiste à mélanger et brûler de multiples types de charbon, comprenant un premier charbon ayant une concentration d'arsenic, en termes de proportion massique, supérieure ou égale 2,0 ppm et un ou plusieurs autres types de charbon différents du premier charbon, le mélange étant effectué d'une manière telle qu'après le mélange, le rapport massique P0 dans le charbon global de la quantité totale de métaux alcalinoterreux, mesurée par la quantité d'oxyde, à la quantité totale d'arsenic est supérieur ou égal à 2 000.
PCT/JP2015/059802 2014-10-30 2015-03-27 Procédé de suppression de l'élution d'arsenic Ceased WO2016067652A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2016540072A JP6079940B2 (ja) 2014-10-30 2015-03-27 ヒ素溶出抑制方法

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2014-222024 2014-10-30
JP2014222024 2014-10-30

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WO2016067652A1 true WO2016067652A1 (fr) 2016-05-06

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008012529A (ja) * 2006-06-09 2008-01-24 Chugoku Electric Power Co Inc:The 排ガス浄化剤及び有害微量元素を捕捉する方法
JP2009275999A (ja) * 2008-05-15 2009-11-26 Chugoku Electric Power Co Inc:The 有害微量元素溶出抑制剤及び有害微量元素溶出抑制方法
JP2009281604A (ja) * 2008-05-20 2009-12-03 Oji Paper Co Ltd 燃焼灰からの規制物質の溶出抑制方法
US20130312321A1 (en) * 2012-05-25 2013-11-28 General Trade Corporation Automated system for sorting and blending coal

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008012529A (ja) * 2006-06-09 2008-01-24 Chugoku Electric Power Co Inc:The 排ガス浄化剤及び有害微量元素を捕捉する方法
JP2009275999A (ja) * 2008-05-15 2009-11-26 Chugoku Electric Power Co Inc:The 有害微量元素溶出抑制剤及び有害微量元素溶出抑制方法
JP2009281604A (ja) * 2008-05-20 2009-12-03 Oji Paper Co Ltd 燃焼灰からの規制物質の溶出抑制方法
US20130312321A1 (en) * 2012-05-25 2013-11-28 General Trade Corporation Automated system for sorting and blending coal

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