WO2010047004A1 - Waste heat recovery facility of arc furnace for steel-making and method for recovering waste heat - Google Patents

Waste heat recovery facility of arc furnace for steel-making and method for recovering waste heat Download PDF

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Publication number
WO2010047004A1
WO2010047004A1 PCT/JP2008/073267 JP2008073267W WO2010047004A1 WO 2010047004 A1 WO2010047004 A1 WO 2010047004A1 JP 2008073267 W JP2008073267 W JP 2008073267W WO 2010047004 A1 WO2010047004 A1 WO 2010047004A1
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WIPO (PCT)
Prior art keywords
waste heat
arc furnace
exhaust gas
steam
steelmaking
Prior art date
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PCT/JP2008/073267
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French (fr)
Japanese (ja)
Inventor
中山道夫
渡部雅之
山▲崎▼政成
奥山芳宜
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スチールプランテック株式会社
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Publication of WO2010047004A1 publication Critical patent/WO2010047004A1/en

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/52—Manufacture of steel in electric furnaces
    • C21C5/5211—Manufacture of steel in electric furnaces in an alternating current [AC] electric arc furnace
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
    • F22B1/18—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines
    • F22B1/183—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines in combination with metallurgical converter installations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
    • F27B3/08—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces heated electrically, with or without any other source of heat
    • F27B3/085—Arc furnaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
    • F27B3/10—Details, accessories, or equipment peculiar to hearth-type furnaces
    • F27B3/26—Arrangements of heat-exchange apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/001—Extraction of waste gases, collection of fumes and hoods used therefor
    • F27D17/003—Extraction of waste gases, collection of fumes and hoods used therefor of waste gases emanating from an electric arc furnace
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/004—Systems for reclaiming waste heat
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C2100/00—Exhaust gas
    • C21C2100/06—Energy from waste gas used in other processes
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/38—Removal of waste gases or dust
    • C21C5/40—Offtakes or separating apparatus for converter waste gases or dust
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Definitions

  • the present invention relates to equipment and a method for recovering steam from exhaust gas sensible heat and combustion heat from a plurality of steelmaking arc furnaces.
  • a steelmaking arc furnace (also referred to as an “electric furnace”) is a facility for melting molten steel by melting and refining raw iron scrap and reduced iron (DRI).
  • Iron scrap often has paint and machine oil adhering to it, and synthetic resin may also be mixed in, and these volatilize or partially burn during heating of iron scrap, resulting in white smoke and malodorous substances. It is mixed in the exhaust gas from the steelmaking arc furnace.
  • carbon monoxide generated by a decarburization reaction or the like in a steelmaking arc furnace cannot be burned and is mixed into exhaust gas.
  • reduced iron is used as a raw material, there is almost no generation of white smoke or malodorous substances, but a large amount of carbon monoxide is generated.
  • FIG. 4 An example of a steelmaking arc furnace exhaust gas treatment system having this combustion tower is shown in FIG.
  • reference numeral 1 is a steel arc furnace
  • 2 is a combustion tower
  • 3 is a water cooling duct
  • 4 is an air cooling duct
  • 5 is a dust collector
  • 6 is an exhaust fan
  • 7 is a chimney.
  • Exhaust gas generated from the steelmaking arc furnace 1 containing unburned components such as carbon monoxide is mixed with the air introduced from the combustion air introduction section (gap seam of the duct) 18 and introduced into the combustion tower 2. Then, the combustion tower 2 spontaneously ignites to completely burn carbon monoxide, white smoke, malodorous substances and the like in the exhaust gas.
  • the air introduced from the combustion air introduction section 18 also functions as a cooling gas by diluting the exhaust gas. Thereafter, the exhaust gas is cooled to about 250 ° C. by the indirect water cooling type water cooling duct 3, further cooled by the air cooling duct 4 and introduced into the dust collector 5, and the dust removed by the dust collector 5 is diffused from the chimney 7 to the atmosphere.
  • 2002-286209 discloses that exhaust gas discharged from a steelmaking arc furnace is burned in a secondary combustion chamber, saturated steam is generated in a boiler provided at a subsequent stage of the secondary combustion chamber, and heat of the exhaust gas is generated.
  • a technique has been proposed in which steam is converted into steam and recovered.
  • the exhaust gas generated from the steelmaking arc furnace reaches a high temperature exceeding 1200 ° C. and contains a great deal of energy, but the temperature of the exhaust gas varies greatly. Since the amount of steam generated is linked to the exhaust gas temperature, the amount of steam generated fluctuates greatly.For example, when steam recovered from exhaust gas sensible heat and combustion heat of a steel arc furnace is used for power generation, the steam is insufficient.
  • Japanese Patent Laid-Open No. 2002-286209 does not disclose anything about this point.
  • the exhaust gas generated from the arc furnace for steelmaking contains a large amount of softened slag particles and dust, when recovering the sensible heat and combustion heat of the exhaust gas with a boiler, the boiler must be softened slag particles and dust in the exhaust gas.
  • Japanese Patent Laid-Open No. 2002-286209 discloses nothing about this point.
  • the present invention has been made in view of such circumstances, and its object is to generate steam when generating steam using the sensible heat and combustion heat of exhaust gas discharged from an arc furnace for steelmaking.
  • the amount can be leveled to make it easier to use in power generation, and moreover, it is possible to recover steam stably without being affected by softened and highly adherent slag particles and dust in the exhaust gas. It is to provide a waste heat recovery facility and recovery method for an arc furnace for steelmaking.
  • a waste heat recovery facility for a steelmaking arc furnace according to a first aspect of the present invention for solving the above-described problem is a steelmaking arc furnace for recovering sensible heat and combustion heat of exhaust gas discharged from a plurality of steelmaking arc furnaces.
  • Waste heat recovery equipment which is located in each steelmaking arc furnace, combines the waste heat boiler that recovers sensible heat and combustion heat of exhaust gas, and the saturated steam generated in the waste heat boiler to form a steam accumulator And a steam accumulator for storing saturated steam generated in the waste heat boiler.
  • the waste heat recovery equipment for a steelmaking arc furnace according to the second invention is the first invention, wherein the heat transfer tube of the waste heat boiler disposed in a temperature range where the exhaust gas temperature is 800 ° C.
  • a waste heat recovery facility for a steelmaking arc furnace according to a third invention is characterized in that, in the first or second invention, the plurality of steelmaking arc furnaces are operated at different operating times. is there.
  • a fourth aspect of the present invention there is provided a method for recovering waste heat from a steelmaking arc furnace, wherein a waste heat boiler that recovers sensible heat and combustion heat of exhaust gas discharged from a steelmaking arc furnace is installed in each of a plurality of steelmaking arc furnaces. ⁇ Each steel arc furnace is operated at different operating times, saturated steam generated in each waste heat boiler is merged, and the amount of saturated steam generated by merging saturated steam is leveled It is what.
  • the waste heat recovery method for a steelmaking arc furnace according to the fifth invention is the fourth invention, wherein the heat transfer tube of the waste heat boiler disposed in a temperature range where the exhaust gas temperature is 800 ° C. or higher is a radiant heat transfer tube. It is characterized by.
  • the waste heat recovery method for a steelmaking arc furnace according to a sixth aspect of the present invention is the fourth or fifth aspect of the present invention in which each steelmaking is performed such that periods of low exhaust gas temperatures from a plurality of steelmaking arc furnaces appear alternately. The operation time of the electric arc furnace is shifted.
  • a waste heat recovery method for an arc furnace for steel making according to a seventh aspect of the present invention is the method for recovering waste heat from a steam accumulator according to any one of the fourth to sixth aspects, wherein the saturated steam generated in each waste heat boiler is combined. It is characterized by storing in a crater.
  • a waste heat recovery method for a steelmaking arc furnace according to an eighth invention is the method according to any one of the fourth to seventh inventions, wherein the exhaust gases of a plurality of steelmaking arc furnaces are merged into one on the downstream side of the waste heat boiler.
  • a superheater for recovering the sensible heat of the combined exhaust gas is installed, and the saturated steam generated in the waste heat boiler is converted into superheated steam by the superheater.
  • FIG. 1 is a diagram showing an example of temperature change at the entrance side and the exit side of exhaust gas from a steelmaking arc furnace in which one heat is 70 minutes.
  • FIG. 2 is a diagram showing an average value of exhaust gas temperatures when the energization start times of the four steelmaking arc furnaces showing the exhaust gas temperature pattern of FIG. 1 are shifted and operated.
  • FIG. 3 is a diagram showing an embodiment of the present invention, and is a diagram showing a configuration for recovering saturated steam from exhaust gas sensible heat and combustion heat from four steelmaking arc furnaces.
  • FIG. 4 is a diagram showing an example of a conventional steelmaking arc furnace exhaust gas treatment system having a combustion tower.
  • FIG. 1 shows an example of temperature changes at the entrance and exit sides of the exhaust gas from the arc furnace for steel making where one heat is 70 minutes.
  • 1 heat refers to a series of processes of raw material (iron source) charging-melting-additional raw material charging-melting-refining-outgoing steel, during which the temperature of the exhaust gas generated from the steelmaking arc furnace is It fluctuates greatly.
  • the exhaust gas temperature rises after the start of energization, and temporarily reaches around 1400 ° C. when the initially charged iron source melts. Once added, the temperature drops to about 400 ° C. Thereafter, as the melting of the additional iron source progresses, the exhaust gas temperature rises again to reach about 1200 ° C., and when the iron source completely dissolves (referred to as “burning out”), it burns down.
  • the temperature is maintained at about 1200 ° C. until a refining period such as decarburization refining or component adjustment performed later.
  • This period during which the exhaust gas temperature is high (hereinafter also referred to as “high temperature period”) continues for 20 to 25 minutes.
  • the exhaust gas temperature decreases with the steel output after the end of the refining period, and decreases to 200 ° C. or less after the completion of the steel output.
  • the period of low temperature of 200 ° C. or lower (hereinafter also referred to as “low temperature period”) is from about 7 to 10 minutes from the completion of steel production to the start of heating by energization of the next heat through the charging of the next heat. continue.
  • the amount of saturated steam recovered using the sensible heat and combustion heat of the exhaust gas varies in accordance with the variation of the exhaust gas inlet temperature of the combustion tower.
  • the rotation speed of the exhaust fan is constant, it has been confirmed that there is not much fluctuation in the exhaust gas flow rate.
  • the operation modes of these steelmaking arc furnaces are generally independent of each other.
  • the high-temperature periods of the exhaust gas from each steelmaking arc furnace may overlap, but they are generally shifted, so the saturated steam generated in each steelmaking arc furnace is unified into one. It was found that the amount of steam after merging would be leveled naturally if merged.
  • FIG. 2 shows the exhaust gas temperature when four steelmaking arc furnaces having the exhaust gas temperature pattern shown in FIG. 1 are installed and the energization start times of the four steelmaking arc furnaces are sequentially operated by 17 to 18 minutes. It is a figure which shows an average value. As shown in FIG. 2, it can be seen that the fluctuation range of the exhaust gas temperature at the entrance of the combustion tower is reduced and the fluctuation period becomes small.
  • the steam amount fluctuation pattern is the fluctuation pattern of the exhaust gas temperature at the combustion tower inlet shown in FIG. It will conform to. That is, steam generated from a plurality of steelmaking arc furnaces is merged into one, and preferably, the low temperature periods of the exhaust gas from each steelmaking arc furnace appear alternately without overlapping. It was found that the steam generation pattern after merging is leveled by controlling the operation mode of the arc furnace. The presence of the steam accumulator makes it easier to level the steam generation pattern.
  • the exhaust gas generated from a steelmaking arc furnace contains a large amount of softened slag particles and dust, and in order to stably recover the sensible heat and combustion heat of the exhaust gas with a waste heat boiler, the boiler heat transfer tube is connected to the exhaust gas. It is desirable to have a structure that is not affected by the softened slag grains and dust inside. Therefore, in the present invention, as a preferred embodiment, the boiler heat transfer tube installed in the temperature range where the exhaust gas temperature is 800 ° C. or higher is only the radiation heat transfer tube.
  • the radiation type heat transfer tube is to form a boundary surface of the heat transfer chamber by the heat transfer tube group which is a steam generation surface, that is, to form a water cooling wall type by the heat transfer tube group.
  • a convection heat transfer tube forms a lattice in the space with a water tube, and hot air flows through the gap, so in a gas containing highly adherent dust, the dust layer attached to the water tube grows to form a bridge, and finally it is blocked There is a fear.
  • use of a convection heat transfer tube is avoided in the high temperature region above the softening temperature of slag (800 ° C. or more) as described above, and only a radiant heat transfer tube having a wall surface constituted by a water tube is employed.
  • the flow rate of the combined steam that fluctuates corresponding to the temperature fluctuation in FIG. Install In order to use steam for power generation or the like, it is preferable to convert saturated steam to superheated steam. Therefore, a steam superheater for converting saturated steam to superheated steam is installed as necessary.
  • the steam superheater which is preferably a convection heat transfer structure, is difficult to install in the high-temperature part where softened slag particles fly, so it combines the exhaust gas from the downstream side of the individual waste heat boiler or from the waste heat boiler. Install after.
  • the present invention has been made based on these findings, and a waste heat boiler for recovering sensible heat and combustion heat of exhaust gas discharged from a steelmaking arc furnace is installed in each of a plurality of steelmaking arc furnaces.
  • the feature is that the saturated steam generated in each of the waste heat boilers is joined, and the amount of the saturated steam is leveled by joining.
  • the boiler heat transfer tube disposed in the temperature range where the exhaust gas temperature is 800 ° C. or higher is a radiant heat transfer tube.
  • the steelmaking arc furnace 1 is a three-phase alternating current type having three electrodes 15, and is an apparatus for melting molten steel 16 by melting iron scrap, reduced iron or the like as an iron source.
  • a slag 17 is formed on the surface of the molten steel 16 using quick lime or the like as a slagging agent.
  • reference numeral 19 denotes an oxygen gas blowing lance for decarburization refining
  • reference numeral 20 denotes a carbonaceous material blowing lance for adding carbonaceous material.
  • the exhaust gas from each steelmaking arc furnace 1 is introduced into a combustion tower 2 in which a radiant heat transfer tube 10 constituting a waste heat boiler is installed on the inner wall, and further into a water cooling duct 3 on the downstream side of the combustion tower 2. It has been introduced. Also on the inner wall of the water-cooled duct 3, a radiant heat transfer tube 10A and a heat transfer tube 10B constituting a waste heat boiler are installed.
  • the heat transfer tube 10A on the upstream side of the water cooling duct 3 and the heat transfer tube 10B on the downstream side are divided into two heat transfer tubes, but even if they are combined into one, they are further divided into three or more. It doesn't matter.
  • the waste heat boiler includes a heat transfer tube (10, 10A, 10B in FIG. 3) and other incidental equipment (for example, a steam drum 8, a circulating water pump 9, etc.).
  • each steel arc furnace 1 is provided with a steam drum 8, and water (pure water) accommodated in the steam drum 8 is transferred by a circulating water pump 9 to a heat transfer tube 10, a heat transfer tube 10 ⁇ / b> A, and a heat transfer tube. 10B.
  • the water sent to the heat transfer tubes at the respective locations is heated by the sensible heat and combustion heat of the exhaust gas generated from the steelmaking arc furnace 1 and returns to the steam drum 8.
  • the steam drum 8 is connected to a pure water tank (not shown), and water is appropriately supplied from the pure water tank so that a predetermined amount of water is accommodated in the steam drum 8.
  • Each steam drum 8 is connected to a steam transport pipe 11, and this steam transport pipe 11 communicates with a steam accumulator 13. Therefore, the saturated steam generated in each steam drum 8 is steamed by the steam transport pipe 11. It is configured to be conveyed to the accumulator 13 and stored in the vapor accumulator 13.
  • the exhaust gas discharged from each steelmaking arc furnace 1 is introduced into the exhaust gas outflow pipe 12 on the downstream side of each water-cooled duct 3, and the exhaust gas from each steelmaking arc furnace 1 is combined into one.
  • a steam superheater 14 is installed in the exhaust gas outlet pipe 12.
  • a dust collector 5 is installed at the subsequent stage of the steam superheater 14, and after the dust is removed by the dust collector 5, the exhaust gas is diffused into the atmosphere through a chimney (not shown).
  • One or more exhaust fans are disposed in the exhaust gas path, and the exhaust gas is blown from the steelmaking arc furnace 1 to the chimney by the exhaust fan.
  • the steam superheater 14 is installed after the exhaust gas merging of each waste heat boiler, but may be individually installed downstream of each waste heat boiler.
  • the steam superheater 14 is composed of a convection type heat transfer tube, and the saturated steam stored in the steam accumulator 13 is converted into superheated steam by the steam superheater 14.
  • the converted superheated steam is supplied to a power supply facility such as a steam turbine power generation facility or a steelmaking factory.
  • a power supply facility such as a steam turbine power generation facility or a steelmaking factory.
  • the steam is recovered from the sensible heat and combustion heat of the exhaust gas of each steelmaking arc furnace 1, and the recovered steam is combined into one, so that the steam is independently generated from each steelmaking arc furnace 1.
  • the amount of steam generated can be leveled.
  • the temperature of the exhaust gas from the steelmaking arc furnace 1 fluctuates, but the exhaust gas temperature decreases from the time when the steel is discharged until the start of energization of the next heat.
  • each steelmaking arc furnace 1 it is preferable to shift the operation time of each steelmaking arc furnace 1 so that low temperature periods with low exhaust gas temperatures from each steelmaking arc furnace 1 appear alternately. That is, the energization start time and the steel output start time may be determined in advance so that the low temperature periods of each steelmaking arc furnace 1 appear alternately.
  • the heat treatment time is X
  • the energization start times of the respective steelmaking arc furnaces 1 are sequentially shifted at intervals of X / N. Just go. However, it is not necessary to accurately shift at an X / N interval, and it is sufficient to have a margin of about 10 minutes before and after.
  • the present invention can be applied to an electric furnace steel factory equipped with three or more arc furnaces 1 for steel making. desirable.
  • steam generated by a waste heat boiler installed in each of a plurality of steelmaking arc furnaces 1 is merged into one path, so that each steelmaking arc furnace 1 is a batch type.
  • the amount of saturated steam generated is different, but the operation status is naturally shifted in each steelmaking arc furnace 1, so the amount of saturated steam after merging is independent of each steelmaking arc furnace 1. Therefore, it is leveled compared with the case of recovering steam.
  • the steelmaking arc furnace 1 is operated with the operation time shifted intentionally, the amount of saturated steam after merging is further leveled, and this steam can be used effectively.
  • Table 1 shows the operation conditions and operation results.
  • the time required for one heat of each steelmaking arc furnace is 70 minutes for all four steelmaking arc furnaces, and each steelmaking arc furnace is sequentially energized at an interval of about 16 minutes.
  • the operation mode was adjusted.
  • the amount of steam generated per one steelmaking arc furnace was instantaneous value: 42 tons / h, 1 heat average: 33 tons / h, and the amount of steam generated was leveled.
  • This saturated steam is stored in a steam accumulator, the stored saturated steam is converted into superheated steam with a steam superheater provided at the subsequent stage of the steam accumulator, and the converted superheated steam is supplied to a steam turbine power generation facility to generate electricity.
  • a steam turbine power generation facility to generate electricity.
  • steam generated by a waste heat boiler installed in each of a plurality of steelmaking arc furnaces is joined to one path, so that each steelmaking arc furnace is a batch-type operation mode, and saturated steam
  • the amount of generated steam fluctuates, but the operational status of each steelmaking arc furnace naturally shifts, so the amount of saturated steam after merging is compared to the case where steam is collected independently from each steelmaking arc furnace. Leveled.
  • the boiler heat transfer tube installed in the temperature range where the exhaust gas temperature is 800 ° C. or higher is a radiant heat transfer tube, adhesion of slag and dust softened at a high temperature to the heat transfer tube is suppressed, Cleaning is easy and it is possible to stably recover saturated steam from exhaust gas sensible heat and combustion heat.

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  • Chemical & Material Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Sustainable Energy (AREA)
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Abstract

In generating steam by utilizing the heat of the waste gas discharged from an arc furnace for steel-making, the object aims to level the generated quantity of steam so as to easily use the steam for power generation. A waste heat boiler for recovering the sensible heat and combustion heat of the waste gas discharged from an arc furnace (1) for steel-making is installed in each of a plurality of the arc furnaces. The arc furnaces are operated at the shifted operation times, and the saturated steam generated in each of the waste heat boilers is converged, whereby the quantities of the generated saturated steams are leveled.

Description

製鋼用アーク炉の廃熱回収設備及び回収方法Waste heat recovery equipment and recovery method for an arc furnace for steelmaking
　本発明は、複数の製鋼用アーク炉からの排ガス顕熱および燃焼熱から蒸気を回収する設備及び方法に関するものである。 The present invention relates to equipment and a method for recovering steam from exhaust gas sensible heat and combustion heat from a plurality of steelmaking arc furnaces.
　製鋼用アーク炉（「電気炉」ともいう）は、原料の鉄スクラップや還元鉄（ＤＲＩ）を溶解・精錬して溶鋼を溶製する設備である。鉄スクラップには、塗料や機械油が付着していることが多く、また、合成樹脂などが混入することもあり、これらが鉄スクラップの加熱中に揮発あるいは一部燃焼し、白煙・悪臭物質として製鋼用アーク炉からの排ガスに混入する。また、製鋼用アーク炉内での脱炭反応などによって生成する一酸化炭素が燃焼しきれず、排ガスに混入する。還元鉄を原料に使用する場合は白煙・悪臭物質などの発生はほとんど無いが、一酸化炭素は大量に発生する。そこで、排ガスに含まれる一酸化炭素及び白煙・悪臭物質などを完全燃焼させるために、通常、製鋼用アーク炉の排ガス処理系統には燃焼塔が設置されている（例えば、特開２０００−３５６４７６号公報を参照）。
　この燃焼塔を有する製鋼用アーク炉排ガス処理系統の例を図４に示す。図４において、符号１は製鋼用アーク炉、２は燃焼塔、３は水冷ダクト、４は空冷ダクト、５は集塵機、６は排気ファン、７は煙突である。一酸化炭素などの未燃分を含有する、製鋼用アーク炉１から発生する排ガスは、燃焼用空気導入部（ダクトの継ぎ目の間隙）１８から導入される空気と混合されて燃焼塔２に導入され、燃焼塔２において自然着火して排ガス中の一酸化炭素及び白煙・悪臭物質などが完全燃焼する。ここで、燃焼用空気導入部１８から導入される空気は、排ガスを希釈することで冷却用ガスとしても機能する。その後、排ガスは間接水冷式の水冷ダクト３で２５０℃程度まで冷却され、更に、空冷ダクト４で冷却されて集塵機５に導入され、集塵機５で除塵された排ガスは、煙突７から大気に放散される。この場合、排ガスは排気ファン６によって製鋼用アーク炉１から煙突７まで送風される。
　燃焼塔２の壁は間接水冷されており、この燃焼塔２及び水冷ダクト３の冷却水量は１００トン規模の製鋼用アーク炉１では１０００トン／ｈに達し、この冷却水の循環用動力及び冷却水の冷却塔（図示せず）での放熱によるエネルギー損失は極めて大きい。
　そこで、この排ガスのエネルギーを回収する方法が提案されている。例えば、特開２００２−２８６２０９号公報には、製鋼用アーク炉から排出される排ガスを二次燃焼室で燃焼させ、二次燃焼室の後段に設けたボイラーで飽和蒸気を生成させ、排ガスの熱を蒸気に変換して回収する技術が提案されている。
　製鋼用アーク炉から発生する排ガスは、１２００℃を越す高温にもなり多大なエネルギーを含有するが、排ガスの温度は大きく変動する。蒸気発生量は排ガス温度と連動することから、蒸気の発生量が大きく変動し、例えば製鋼用アーク炉の排ガス顕熱および燃焼熱から回収した蒸気を発電などに使用する場合、蒸気が不足して発電量を低下せざるを得ない、あるいは発電を停止せざるを得ないなどのトラブル発生の恐れがあり、これまで発生蒸気を発電に利用した例はない。しかし、特開２００２−２８６２０９号公報はこの点に関して何ら開示していない。
　また、製鋼用アーク炉から発生する排ガスは、軟化スラグ粒やダストを多量に含むことから、排ガスの顕熱および燃焼熱をボイラーで回収する際には、ボイラーを排ガス中の軟化スラグ粒やダストの影響を受けない構造にする必要があるが、特開２００２−２８６２０９号公報はこの点に関しても何ら開示していない。
　本発明はこのような事情に鑑みてなされたもので、その目的とするところは、製鋼用アーク炉から排出される排ガスの顕熱および燃焼熱を利用して蒸気を生成するにあたり、蒸気の発生量を、発電などで利用しやすくするために平準化することができ、更に、排ガス中の軟化した付着性の高いスラグ粒やダストの影響を受けることなく安定して蒸気を回収することのできる、製鋼用アーク炉の廃熱回収設備及び回収方法を提供することである。 A steelmaking arc furnace (also referred to as an “electric furnace”) is a facility for melting molten steel by melting and refining raw iron scrap and reduced iron (DRI). Iron scrap often has paint and machine oil adhering to it, and synthetic resin may also be mixed in, and these volatilize or partially burn during heating of iron scrap, resulting in white smoke and malodorous substances. It is mixed in the exhaust gas from the steelmaking arc furnace. In addition, carbon monoxide generated by a decarburization reaction or the like in a steelmaking arc furnace cannot be burned and is mixed into exhaust gas. When reduced iron is used as a raw material, there is almost no generation of white smoke or malodorous substances, but a large amount of carbon monoxide is generated. Therefore, in order to completely burn carbon monoxide, white smoke, malodorous substances and the like contained in the exhaust gas, a combustion tower is usually installed in the exhaust gas treatment system of the steelmaking arc furnace (for example, JP 2000-356476 A). Issue no.).
An example of a steelmaking arc furnace exhaust gas treatment system having this combustion tower is shown in FIG. In FIG. 4, reference numeral 1 is a steel arc furnace, 2 is a combustion tower, 3 is a water cooling duct, 4 is an air cooling duct, 5 is a dust collector, 6 is an exhaust fan, and 7 is a chimney. Exhaust gas generated from the steelmaking arc furnace 1 containing unburned components such as carbon monoxide is mixed with the air introduced from the combustion air introduction section (gap seam of the duct) 18 and introduced into the combustion tower 2. Then, the combustion tower 2 spontaneously ignites to completely burn carbon monoxide, white smoke, malodorous substances and the like in the exhaust gas. Here, the air introduced from the combustion air introduction section 18 also functions as a cooling gas by diluting the exhaust gas. Thereafter, the exhaust gas is cooled to about 250 ° C. by the indirect water cooling type water cooling duct 3, further cooled by the air cooling duct 4 and introduced into the dust collector 5, and the dust removed by the dust collector 5 is diffused from the chimney 7 to the atmosphere. The In this case, exhaust gas is blown from the steelmaking arc furnace 1 to the chimney 7 by the exhaust fan 6.
The wall of the combustion tower 2 is indirectly cooled with water, and the amount of cooling water in the combustion tower 2 and the water cooling duct 3 reaches 1000 tons / h in the 100-ton steelmaking arc furnace 1, and the cooling water circulation power and cooling Energy loss due to heat dissipation in a water cooling tower (not shown) is extremely large.
Therefore, a method for recovering the energy of the exhaust gas has been proposed. For example, Japanese Patent Application Laid-Open No. 2002-286209 discloses that exhaust gas discharged from a steelmaking arc furnace is burned in a secondary combustion chamber, saturated steam is generated in a boiler provided at a subsequent stage of the secondary combustion chamber, and heat of the exhaust gas is generated. A technique has been proposed in which steam is converted into steam and recovered.
The exhaust gas generated from the steelmaking arc furnace reaches a high temperature exceeding 1200 ° C. and contains a great deal of energy, but the temperature of the exhaust gas varies greatly. Since the amount of steam generated is linked to the exhaust gas temperature, the amount of steam generated fluctuates greatly.For example, when steam recovered from exhaust gas sensible heat and combustion heat of a steel arc furnace is used for power generation, the steam is insufficient. There is a possibility of troubles such as the necessity to reduce the amount of power generation or the necessity to stop the power generation, and there has been no example of using the generated steam for power generation so far. However, Japanese Patent Laid-Open No. 2002-286209 does not disclose anything about this point.
In addition, since the exhaust gas generated from the arc furnace for steelmaking contains a large amount of softened slag particles and dust, when recovering the sensible heat and combustion heat of the exhaust gas with a boiler, the boiler must be softened slag particles and dust in the exhaust gas. However, Japanese Patent Laid-Open No. 2002-286209 discloses nothing about this point.
The present invention has been made in view of such circumstances, and its object is to generate steam when generating steam using the sensible heat and combustion heat of exhaust gas discharged from an arc furnace for steelmaking. The amount can be leveled to make it easier to use in power generation, and moreover, it is possible to recover steam stably without being affected by softened and highly adherent slag particles and dust in the exhaust gas. It is to provide a waste heat recovery facility and recovery method for an arc furnace for steelmaking.
　上記課題を解決するための第１の発明に係る製鋼用アーク炉の廃熱回収設備は、複数の製鋼用アーク炉から排出される排ガスの顕熱および燃焼熱を回収するための製鋼用アーク炉の廃熱回収設備であって、それぞれの製鋼用アーク炉に配置された、排ガスの顕熱および燃焼熱を回収する廃熱ボイラーと、廃熱ボイラーで発生した飽和蒸気を合流させて蒸気アキュムレーターに搬送する蒸気搬送経路と、廃熱ボイラーで発生した飽和蒸気を貯留するための蒸気アキュムレーターと、を備えることを特徴とするものである。
　第２の発明に係る製鋼用アーク炉の廃熱回収設備は、第１の発明において、排ガス温度が８００℃以上の温度域に配置される廃熱ボイラーの伝熱管は輻射型伝熱管であることを特徴とするものである。
　第３の発明に係る製鋼用アーク炉の廃熱回収設備は、第１または第２の発明において、複数の製鋼用アーク炉が、それぞれ運転時間をずらして稼働されることを特徴とするものである。
　第４の発明に係る製鋼用アーク炉の廃熱回収方法は、製鋼用アーク炉から排出される排ガスの顕熱および燃焼熱を回収する廃熱ボイラーを、複数の製鋼用アーク炉にそれぞれ設置し、それぞれの製鋼用アーク炉を運転時間をずらして稼働させ、それぞれの廃熱ボイラーで発生する飽和蒸気を合流させ、飽和蒸気を合流することで発生する飽和蒸気の量を平準化させることを特徴とするものである。
　第５の発明に係る製鋼用アーク炉の廃熱回収方法は、第４の発明において、排ガス温度が８００℃以上の温度域に配置される廃熱ボイラーの伝熱管は輻射型伝熱管であることを特徴とするものである。
　第６の発明に係る製鋼用アーク炉の廃熱回収方法は、第４または第５の発明において、複数の製鋼用アーク炉からの排ガス温度の低い期間が交互に出現するように、それぞれの製鋼用アーク炉の運転時間をずらすことを特徴とするものである。
　第７の発明に係る製鋼用アーク炉の廃熱回収方法は、第４ないし第６の発明の何れかにおいて、それぞれの廃熱ボイラーで発生する飽和蒸気を合流させた後の飽和蒸気を蒸気アキュムレーターに貯留することを特徴とするものである。
　第８の発明に係る製鋼用アーク炉の廃熱回収方法は、第４ないし第７の発明の何れかにおいて、複数の製鋼用アーク炉の排ガスを廃熱ボイラーの下流側で１つに合流させ、合流させた排ガスの顕熱を回収するための過熱器を設置し、該過熱器により、廃熱ボイラーで発生した飽和蒸気を過熱蒸気に変換することを特徴とするものである。 A waste heat recovery facility for a steelmaking arc furnace according to a first aspect of the present invention for solving the above-described problem is a steelmaking arc furnace for recovering sensible heat and combustion heat of exhaust gas discharged from a plurality of steelmaking arc furnaces. Waste heat recovery equipment, which is located in each steelmaking arc furnace, combines the waste heat boiler that recovers sensible heat and combustion heat of exhaust gas, and the saturated steam generated in the waste heat boiler to form a steam accumulator And a steam accumulator for storing saturated steam generated in the waste heat boiler.
The waste heat recovery equipment for a steelmaking arc furnace according to the second invention is the first invention, wherein the heat transfer tube of the waste heat boiler disposed in a temperature range where the exhaust gas temperature is 800 ° C. or higher is a radiant heat transfer tube. It is characterized by.
A waste heat recovery facility for a steelmaking arc furnace according to a third invention is characterized in that, in the first or second invention, the plurality of steelmaking arc furnaces are operated at different operating times. is there.
According to a fourth aspect of the present invention, there is provided a method for recovering waste heat from a steelmaking arc furnace, wherein a waste heat boiler that recovers sensible heat and combustion heat of exhaust gas discharged from a steelmaking arc furnace is installed in each of a plurality of steelmaking arc furnaces.・ Each steel arc furnace is operated at different operating times, saturated steam generated in each waste heat boiler is merged, and the amount of saturated steam generated by merging saturated steam is leveled It is what.
The waste heat recovery method for a steelmaking arc furnace according to the fifth invention is the fourth invention, wherein the heat transfer tube of the waste heat boiler disposed in a temperature range where the exhaust gas temperature is 800 ° C. or higher is a radiant heat transfer tube. It is characterized by.
The waste heat recovery method for a steelmaking arc furnace according to a sixth aspect of the present invention is the fourth or fifth aspect of the present invention in which each steelmaking is performed such that periods of low exhaust gas temperatures from a plurality of steelmaking arc furnaces appear alternately. The operation time of the electric arc furnace is shifted.
A waste heat recovery method for an arc furnace for steel making according to a seventh aspect of the present invention is the method for recovering waste heat from a steam accumulator according to any one of the fourth to sixth aspects, wherein the saturated steam generated in each waste heat boiler is combined. It is characterized by storing in a crater.
A waste heat recovery method for a steelmaking arc furnace according to an eighth invention is the method according to any one of the fourth to seventh inventions, wherein the exhaust gases of a plurality of steelmaking arc furnaces are merged into one on the downstream side of the waste heat boiler. A superheater for recovering the sensible heat of the combined exhaust gas is installed, and the saturated steam generated in the waste heat boiler is converted into superheated steam by the superheater.
　図１は、１ヒートが７０分である製鋼用アーク炉からの排ガスの燃焼塔入側及び出側での温度変化の例を示す図である。
　図２は、図１の排ガス温度パターンを示す製鋼用アーク炉４基の通電開始時刻をずらして稼働させたときの排ガス温度の平均値を示す図である。
　図３は、本発明の実施の形態例を示す図であり、４基の製鋼用アーク炉からの排ガス顕熱および燃焼熱から飽和蒸気を回収する構成を示す図である。
　図４は、燃焼塔を有する従来の製鋼用アーク炉排ガス処理系統の例を示す図である。 FIG. 1 is a diagram showing an example of temperature change at the entrance side and the exit side of exhaust gas from a steelmaking arc furnace in which one heat is 70 minutes.
FIG. 2 is a diagram showing an average value of exhaust gas temperatures when the energization start times of the four steelmaking arc furnaces showing the exhaust gas temperature pattern of FIG. 1 are shifted and operated.
FIG. 3 is a diagram showing an embodiment of the present invention, and is a diagram showing a configuration for recovering saturated steam from exhaust gas sensible heat and combustion heat from four steelmaking arc furnaces.
FIG. 4 is a diagram showing an example of a conventional steelmaking arc furnace exhaust gas treatment system having a combustion tower.
符号の説明Explanation of symbols
　１　製鋼用アーク炉、　２　燃焼塔、　３　水冷ダクト、　４　空冷ダクト、　５　集塵機、　６　排気ファン、　７　煙突、　８　蒸気ドラム、　９　循環水ポンプ、　１０　伝熱管、１１　蒸気搬送管、　１２　排ガス流出管、　１３　蒸気アキュムレーター
　１４　蒸気過熱器、　１５　電極、　１６　溶鋼、　１７　スラグ、　１８　燃焼用空気導入部、　１９　酸素ガス吹込ランス、　２０　炭材吹込ランス DESCRIPTION OF SYMBOLS 1 Steelmaking arc furnace, 2 Combustion tower, 3 Water cooling duct, 4 Air cooling duct, 5 Dust collector, 6 Exhaust fan, 7 Chimney, 8 Steam drum, 9 Circulating water pump, 10 Heat transfer pipe, 11 Steam conveyance pipe, 12 Exhaust gas outflow pipe , 13 Steam accumulator 14 Steam superheater, 15 Electrode, 16 Molten steel, 17 Slag, 18 Combustion air introduction part, 19 Oxygen gas injection lance, 20 Carbon material injection lance
　以下、本発明を具体的に説明する。
　製鋼用アーク炉から排出される排ガスの顕熱および燃焼熱を利用して廃熱ボイラーで飽和蒸気を回収した場合、製鋼用アーク炉の稼動形態はバッチ式であるので、蒸気の発生が途絶える期間が生じる。蒸気の発生量のばらつきが大きいと、例えば、この蒸気を利用して電気炉製鋼工場で使用する電力を発電するなどの場合のリスクが大きく、蒸気の有効活用が困難である。本発明者らは、この問題を解決するべく検討を実施した。
　図１に、１ヒートが７０分である製鋼用アーク炉からの排ガスの燃焼塔入側及び出側での温度変化の例を示す。ここで、１ヒートとは、原料（鉄源）装入−溶解−原料追加装入−溶解−精錬−出鋼という、一連のプロセスを示し、この間に製鋼用アーク炉から発生する排ガスの温度は大きく変動する。例えば、図１の燃焼塔入口温度で示すように、通電開始後から排ガス温度は上昇し、最初に装入した鉄源が溶解するころには一時的に１４００℃近傍に達するが、鉄源の追加装入によって一旦４００℃程度まで低下する。その後、追加装入した鉄源の溶解の進行に伴って排ガス温度は再度上昇して１２００℃程度に達し、完全に鉄源が溶解する時点（「溶け落ち」という）を経過して、溶け落ち後に実施する脱炭精錬や成分調整などの精錬期間まで、１２００℃程度に維持される。この排ガス温度の高い期間（以下、「高温期」ともいう）は２０~２５分間継続する。
　一方、精錬期間終了後の出鋼に伴って排ガス温度は低下し、出鋼完了後には２００℃以下に低下する。そして、出鋼完了後から次ヒートの原料装入を経て次ヒートの通電開始による昇温開始まで、２００℃以下の温度の低い期間（以下、「低温期」ともいう）が７~１０分間程度継続する。
　この排ガスの顕熱および燃焼熱を利用して回収される飽和蒸気の量は、排ガスの燃焼塔入口温度の変動に対応して変動することになる。尚、排気ファンの回転数が一定の場合は、排ガス風量の変動は余りないことを確認している。
　ところで、複数の製鋼用アーク炉が設置された電気炉製鋼工場では、これらの製鋼用アーク炉の稼働形態は、一般的にはそれぞれ独立している。つまり、それぞれの製鋼用アーク炉からの排ガスの高温期は、重なり合うこともあるが、ずれることの方が一般的であり、従って、それぞれの製鋼用アーク炉で生成される飽和蒸気を１つに合流させれば、自ずと合流後の蒸気量は平準化されるとの知見を得た。また、それぞれの製鋼用アーク炉からの排ガスの低温期が重ならずに交互に出現するように、意図的に製鋼用アーク炉の稼働形態を制御した場合には、蒸気量はより一層平準化されるとの知見を得た。
　図２は、図１の排ガス温度パターンを示す製鋼用アーク炉を４基設置し、４基の製鋼用アーク炉の通電開始時刻を１７~１８分、順次ずらして稼働させたときの排ガス温度の平均値を示す図である。図２に示すように、燃焼塔入口での排ガス温度の変動幅は軽減され、且つ変動周期は小さくなることが分かる。それぞれの製鋼用アーク炉に廃熱ボイラーを設置し、それぞれの廃熱ボイラーで発生する飽和蒸気を合流させた場合の蒸気量変動パターンは、図２に示す燃焼塔入口での排ガス温度の変動パターンに準じることになる。
　即ち、複数の製鋼用アーク炉からの発生蒸気を１つに合流させ、好ましくは、それぞれの製鋼用アーク炉からの排ガスの低温期が重ならずに交互に出現するように、それぞれの製鋼用アーク炉の稼働形態を制御することによって、合流させた後の蒸気発生パターンは平準化されるとの知見を得た。なお蒸気アキュムレータが存在することにより蒸気発生パターンの平準化はさらに容易になる。
　また、製鋼用アーク炉から発生する排ガスは、軟化スラグ粒やダストを多量に含んでおり、排ガスの顕熱および燃焼熱を廃熱ボイラーで安定して回収するためには、ボイラー伝熱管を排ガス中の軟化スラグ粒やダストの影響を受けない構造にすることが望ましい。そこで、本発明では、好ましい形態として、排ガス温度が８００℃以上の温度域に設置されるボイラー伝熱管を輻射型伝熱管のみとした。ここで、輻射型伝熱管とは、蒸気発生面である伝熱管群で熱伝達室の境界面を形成させること、つまり、伝熱管群により水冷壁形式を形成することである。ボイラー伝熱管によって水冷壁を形成するので、軟化スラグ粒やダストは付着しにくく、また付着しても容易に剥離させることができる。
　一方、対流伝熱管は、水管で空間に格子を作り、その隙間に熱風を流すので、付着性の高いダストを含むガスでは、水管に付着したダスト層が成長してブリッジを作り、最後は閉塞する恐れがある。この現象を避けるために、上記のようにスラグの軟化温度以上（８００℃以上）の高温域では対流伝熱管の使用を避けて、水管で壁面を構成する輻射伝熱管のみを採用する。排ガス温度がこの温度以下の下流側には、対流型伝熱管を設置しても問題はない。
　本発明においては、図２の温度変動に対応して変動する合流蒸気の流量を更に平準化すると同時に、生成した蒸気を貯留するために、飽和蒸気の合流部後段（下流側）にアキュムレーターを設置する。また、蒸気を発電などに利用するためには飽和蒸気を過熱蒸気に変換することが好ましく、従って、必要に応じて飽和蒸気を過熱蒸気に変換するための蒸気過熱器を設置する。構造上対流伝熱形式とすることが好ましい蒸気過熱器は、軟化スラグ粒が飛来する高温部には設置困難であるため、個別の廃熱ボイラーの下流側または廃熱ボイラーからの排ガスを合流させた以降に設置する。
　本発明は、これらの知見に基づきなされたものであり、製鋼用アーク炉から排出される排ガスの顕熱および燃焼熱を回収するための廃熱ボイラーを、複数の製鋼用アーク炉にそれぞれ設置し、それぞれの廃熱ボイラーで発生する飽和蒸気を合流させ、合流させることで飽和蒸気の量を平準化することを特徴としている。この場合、排ガス温度が８００℃以上の温度域に配置するボイラー伝熱管は輻射型伝熱管とすることが好ましい。
　以下、本発明の具体的な実施の形態例を図面を参照して説明する。図３は、本発明の実施の形態例を示す図であり、４基の製鋼用アーク炉からの排ガス顕熱および燃焼熱から飽和蒸気を回収する構成を示す図である。
　図３において、製鋼用アーク炉１は、３本の電極１５を有する３相交流型であり、鉄スクラップや還元鉄などを鉄源として溶解し、溶鋼１６を溶製する装置である。溶鋼１６の湯面上には生石灰などを造滓剤としてスラグ１７が形成されている。図３において、符号１９は脱炭精錬用の酸素ガス吹込ランス、符号２０は、炭材添加用の炭材吹込ランスである。
　それぞれの製鋼用アーク炉１の排ガスは、廃熱ボイラーを構成する輻射型の伝熱管１０がその内壁に設置された燃焼塔２に導入され、更に、燃焼塔２の下流側の水冷ダクト３に導入されるようになっている。水冷ダクト３の内壁にも、廃熱ボイラーを構成する輻射型の伝熱管１０Ａ及び伝熱管１０Ｂが設置されている。図３では、水冷ダクト３の上流側の伝熱管１０Ａと下流側の伝熱管１０Ｂとで伝熱管を２つに分けて配置しているが、１つにまとめても更には３つ以上に分けても構わない。燃焼塔２では、排ガス中の一酸化炭素及び白煙・悪臭物質などが、燃焼用空気導入部１８から導入される空気と混合されて完全燃焼する。この燃焼熱により排ガス温度は更に上昇する。なお廃熱ボイラーとは本体である伝熱管（図３における１０、１０Ａ、１０Ｂ）とその他の付帯設備（例えば蒸気ドラム８、循環水ポンプ９等）を含むものである。
　また、それぞれの製鋼用アーク炉１には、蒸気ドラム８が設置されており、蒸気ドラム８に収容された水（純水）は、循環水ポンプ９により伝熱管１０、伝熱管１０Ａ及び伝熱管１０Ｂに送られる。そして、それぞれの箇所の伝熱管に送られた水は、製鋼用アーク炉１から発生する排ガスの顕熱および燃焼熱により昇熱され、蒸気ドラム８に戻る。蒸気ドラム８において気水分離され、飽和蒸気が形成される。尚、蒸気ドラム８は純水タンク（図示せず）と接続しており、蒸気ドラム８に所定量の水が収容されるように、適宜、純水タンクから水が供給される。
　各蒸気ドラム８は蒸気搬送管１１と接続されており、この蒸気搬送管１１は蒸気アキュムレーター１３と連通しており、従って、各蒸気ドラム８で発生した飽和蒸気は蒸気搬送管１１により、蒸気アキュムレーター１３に搬送され、蒸気アキュムレーター１３で貯留されるように構成されている。
　一方、各製鋼用アーク炉１から排出される排ガスは、それぞれの水冷ダクト３の下流側で排ガス流出管１２に導入され、それぞれの製鋼用アーク炉１からの排ガスが１つにまとまった以降の排ガス流出管１２に、蒸気過熱器１４が設置されている。蒸気過熱器１４の後段には集塵機５が設置されており、集塵機５で除塵された後、排ガスは煙突（図示せず）を介して大気に放散される。この排ガスの経路には１基以上の排気ファン（図示せず）が配置されており、排ガスは、排気ファンによって製鋼用アーク炉１から煙突まで送風される。尚、この例では蒸気過熱器１４は、各廃熱ボイラーの排ガス合流後に設置されているが、各廃熱ボイラーごとにその下流に個別に設置してもよい。
　蒸気過熱器１４は対流式の伝熱管で構成されており、蒸気アキュムレーター１３で貯留された飽和蒸気は、蒸気過熱器１４によって過熱蒸気に変換される。変換された過熱蒸気は蒸気タービン式発電設備や製鋼工場等の動力供給設備などに供給される。
　このようにして、それぞれの製鋼用アーク炉１の排ガスの顕熱および燃焼熱から蒸気を回収し、回収した蒸気を１つにまとめるので、個々の製鋼用アーク炉１からそれぞれ独立して蒸気を回収する場合に比較して、蒸気の生成量を平準化することができる。
　更に、蒸気の生成量を平準化させるために、意図的にそれぞれの製鋼用アーク炉１の稼働形態を制御することが好ましい。図１に示すように、製鋼用アーク炉１からの排ガスの温度は変動するが、出鋼から次ヒートの通電開始までは排ガス温度が低くなる。各製鋼用アーク炉１からの排ガス温度の低い低温期が交互に出現するように、それぞれの製鋼用アーク炉１の運転時間をずらすことが好ましい。
　つまり、各製鋼用アーク炉１の低温期が交互に現れるように、予め、通電開始時刻や出鋼開始時刻を決定しておけばよい。端的にいえば、Ｎ基の製鋼用アーク炉１が存在する場合に、１ヒートの処理時間をＸとすれば、Ｘ／Ｎの間隔でそれぞれの製鋼用アーク炉１の通電開始時刻を順次ずらしていけばよい。但し、正確にＸ／Ｎの間隔でずらすことは必要でなく、前後に１０分間程度の余裕を持っても十分である。また、製鋼用アーク炉１の基数が多いほど、蒸気の平準化は容易であり、この観点から、３基以上の製鋼用アーク炉１を備えた電気炉製鋼工場に本発明を適用することが望ましい。
　以上説明したように、本発明によれば、複数の製鋼用アーク炉１にそれぞれ設置した廃熱ボイラーで生成される蒸気を１つの経路に合流させるので、それぞれの製鋼用アーク炉１はバッチ形式の稼働形態であり、飽和蒸気の発生量は異なるが、それぞれの製鋼用アーク炉１で自ずと稼働状況がずれるので、合流後の飽和蒸気の量は、個々の製鋼用アーク炉１からそれぞれ独立して蒸気を回収する場合に比較して平準化される。特に、意図的に運転時間をずらして製鋼用アーク炉１を稼働させたときには、合流後の飽和蒸気の量は更に平準化されて、この蒸気を有効活用することが可能となる。 The present invention will be specifically described below.
When saturated steam is recovered by a waste heat boiler using the sensible heat and combustion heat of exhaust gas discharged from a steelmaking arc furnace, the operation mode of the steelmaking arc furnace is a batch type, so the period when steam generation stops Occurs. When the variation in the amount of generated steam is large, for example, there is a large risk in the case of generating electric power used in an electric furnace steel factory using this steam, and it is difficult to effectively use the steam. The present inventors have studied to solve this problem.
FIG. 1 shows an example of temperature changes at the entrance and exit sides of the exhaust gas from the arc furnace for steel making where one heat is 70 minutes. Here, 1 heat refers to a series of processes of raw material (iron source) charging-melting-additional raw material charging-melting-refining-outgoing steel, during which the temperature of the exhaust gas generated from the steelmaking arc furnace is It fluctuates greatly. For example, as shown by the combustion tower inlet temperature in FIG. 1, the exhaust gas temperature rises after the start of energization, and temporarily reaches around 1400 ° C. when the initially charged iron source melts. Once added, the temperature drops to about 400 ° C. Thereafter, as the melting of the additional iron source progresses, the exhaust gas temperature rises again to reach about 1200 ° C., and when the iron source completely dissolves (referred to as “burning out”), it burns down. The temperature is maintained at about 1200 ° C. until a refining period such as decarburization refining or component adjustment performed later. This period during which the exhaust gas temperature is high (hereinafter also referred to as “high temperature period”) continues for 20 to 25 minutes.
On the other hand, the exhaust gas temperature decreases with the steel output after the end of the refining period, and decreases to 200 ° C. or less after the completion of the steel output. The period of low temperature of 200 ° C. or lower (hereinafter also referred to as “low temperature period”) is from about 7 to 10 minutes from the completion of steel production to the start of heating by energization of the next heat through the charging of the next heat. continue.
The amount of saturated steam recovered using the sensible heat and combustion heat of the exhaust gas varies in accordance with the variation of the exhaust gas inlet temperature of the combustion tower. In addition, when the rotation speed of the exhaust fan is constant, it has been confirmed that there is not much fluctuation in the exhaust gas flow rate.
By the way, in an electric furnace steelmaking factory where a plurality of steelmaking arc furnaces are installed, the operation modes of these steelmaking arc furnaces are generally independent of each other. In other words, the high-temperature periods of the exhaust gas from each steelmaking arc furnace may overlap, but they are generally shifted, so the saturated steam generated in each steelmaking arc furnace is unified into one. It was found that the amount of steam after merging would be leveled naturally if merged. In addition, when the operation mode of the steelmaking arc furnace is intentionally controlled so that the low temperature periods of the exhaust gas from each steelmaking arc furnace appear alternately without overlapping, the steam volume is further leveled. I got the knowledge to be.
FIG. 2 shows the exhaust gas temperature when four steelmaking arc furnaces having the exhaust gas temperature pattern shown in FIG. 1 are installed and the energization start times of the four steelmaking arc furnaces are sequentially operated by 17 to 18 minutes. It is a figure which shows an average value. As shown in FIG. 2, it can be seen that the fluctuation range of the exhaust gas temperature at the entrance of the combustion tower is reduced and the fluctuation period becomes small. When the waste heat boiler is installed in each steelmaking arc furnace and the saturated steam generated in each waste heat boiler is merged, the steam amount fluctuation pattern is the fluctuation pattern of the exhaust gas temperature at the combustion tower inlet shown in FIG. It will conform to.
That is, steam generated from a plurality of steelmaking arc furnaces is merged into one, and preferably, the low temperature periods of the exhaust gas from each steelmaking arc furnace appear alternately without overlapping. It was found that the steam generation pattern after merging is leveled by controlling the operation mode of the arc furnace. The presence of the steam accumulator makes it easier to level the steam generation pattern.
In addition, the exhaust gas generated from a steelmaking arc furnace contains a large amount of softened slag particles and dust, and in order to stably recover the sensible heat and combustion heat of the exhaust gas with a waste heat boiler, the boiler heat transfer tube is connected to the exhaust gas. It is desirable to have a structure that is not affected by the softened slag grains and dust inside. Therefore, in the present invention, as a preferred embodiment, the boiler heat transfer tube installed in the temperature range where the exhaust gas temperature is 800 ° C. or higher is only the radiation heat transfer tube. Here, the radiation type heat transfer tube is to form a boundary surface of the heat transfer chamber by the heat transfer tube group which is a steam generation surface, that is, to form a water cooling wall type by the heat transfer tube group. Since the water-cooled wall is formed by the boiler heat transfer tube, the softened slag particles and dust are difficult to adhere and can be easily separated even if they adhere.
On the other hand, a convection heat transfer tube forms a lattice in the space with a water tube, and hot air flows through the gap, so in a gas containing highly adherent dust, the dust layer attached to the water tube grows to form a bridge, and finally it is blocked There is a fear. In order to avoid this phenomenon, use of a convection heat transfer tube is avoided in the high temperature region above the softening temperature of slag (800 ° C. or more) as described above, and only a radiant heat transfer tube having a wall surface constituted by a water tube is employed. There is no problem even if a convection type heat transfer tube is installed downstream of the exhaust gas temperature below this temperature.
In the present invention, the flow rate of the combined steam that fluctuates corresponding to the temperature fluctuation in FIG. Install. In order to use steam for power generation or the like, it is preferable to convert saturated steam to superheated steam. Therefore, a steam superheater for converting saturated steam to superheated steam is installed as necessary. The steam superheater, which is preferably a convection heat transfer structure, is difficult to install in the high-temperature part where softened slag particles fly, so it combines the exhaust gas from the downstream side of the individual waste heat boiler or from the waste heat boiler. Install after.
The present invention has been made based on these findings, and a waste heat boiler for recovering sensible heat and combustion heat of exhaust gas discharged from a steelmaking arc furnace is installed in each of a plurality of steelmaking arc furnaces. The feature is that the saturated steam generated in each of the waste heat boilers is joined, and the amount of the saturated steam is leveled by joining. In this case, it is preferable that the boiler heat transfer tube disposed in the temperature range where the exhaust gas temperature is 800 ° C. or higher is a radiant heat transfer tube.
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 3 is a diagram showing an embodiment of the present invention, and is a diagram showing a configuration for recovering saturated steam from exhaust gas sensible heat and combustion heat from four steelmaking arc furnaces.
In FIG. 3, the steelmaking arc furnace 1 is a three-phase alternating current type having three electrodes 15, and is an apparatus for melting molten steel 16 by melting iron scrap, reduced iron or the like as an iron source. A slag 17 is formed on the surface of the molten steel 16 using quick lime or the like as a slagging agent. In FIG. 3, reference numeral 19 denotes an oxygen gas blowing lance for decarburization refining, and reference numeral 20 denotes a carbonaceous material blowing lance for adding carbonaceous material.
The exhaust gas from each steelmaking arc furnace 1 is introduced into a combustion tower 2 in which a radiant heat transfer tube 10 constituting a waste heat boiler is installed on the inner wall, and further into a water cooling duct 3 on the downstream side of the combustion tower 2. It has been introduced. Also on the inner wall of the water-cooled duct 3, a radiant heat transfer tube 10A and a heat transfer tube 10B constituting a waste heat boiler are installed. In FIG. 3, the heat transfer tube 10A on the upstream side of the water cooling duct 3 and the heat transfer tube 10B on the downstream side are divided into two heat transfer tubes, but even if they are combined into one, they are further divided into three or more. It doesn't matter. In the combustion tower 2, carbon monoxide, white smoke, malodorous substances, etc. in the exhaust gas are mixed with the air introduced from the combustion air introduction unit 18 and completely burned. The exhaust gas temperature further increases due to this combustion heat. The waste heat boiler includes a heat transfer tube (10, 10A, 10B in FIG. 3) and other incidental equipment (for example, a steam drum 8, a circulating water pump 9, etc.).
In addition, each steel arc furnace 1 is provided with a steam drum 8, and water (pure water) accommodated in the steam drum 8 is transferred by a circulating water pump 9 to a heat transfer tube 10, a heat transfer tube 10 </ b> A, and a heat transfer tube. 10B. The water sent to the heat transfer tubes at the respective locations is heated by the sensible heat and combustion heat of the exhaust gas generated from the steelmaking arc furnace 1 and returns to the steam drum 8. Steam and water are separated in the steam drum 8 to form saturated steam. The steam drum 8 is connected to a pure water tank (not shown), and water is appropriately supplied from the pure water tank so that a predetermined amount of water is accommodated in the steam drum 8.
Each steam drum 8 is connected to a steam transport pipe 11, and this steam transport pipe 11 communicates with a steam accumulator 13. Therefore, the saturated steam generated in each steam drum 8 is steamed by the steam transport pipe 11. It is configured to be conveyed to the accumulator 13 and stored in the vapor accumulator 13.
On the other hand, the exhaust gas discharged from each steelmaking arc furnace 1 is introduced into the exhaust gas outflow pipe 12 on the downstream side of each water-cooled duct 3, and the exhaust gas from each steelmaking arc furnace 1 is combined into one. A steam superheater 14 is installed in the exhaust gas outlet pipe 12. A dust collector 5 is installed at the subsequent stage of the steam superheater 14, and after the dust is removed by the dust collector 5, the exhaust gas is diffused into the atmosphere through a chimney (not shown). One or more exhaust fans (not shown) are disposed in the exhaust gas path, and the exhaust gas is blown from the steelmaking arc furnace 1 to the chimney by the exhaust fan. In this example, the steam superheater 14 is installed after the exhaust gas merging of each waste heat boiler, but may be individually installed downstream of each waste heat boiler.
The steam superheater 14 is composed of a convection type heat transfer tube, and the saturated steam stored in the steam accumulator 13 is converted into superheated steam by the steam superheater 14. The converted superheated steam is supplied to a power supply facility such as a steam turbine power generation facility or a steelmaking factory.
In this way, the steam is recovered from the sensible heat and combustion heat of the exhaust gas of each steelmaking arc furnace 1, and the recovered steam is combined into one, so that the steam is independently generated from each steelmaking arc furnace 1. Compared to the case of recovery, the amount of steam generated can be leveled.
Furthermore, it is preferable to intentionally control the operation mode of each steelmaking arc furnace 1 in order to level the generated amount of steam. As shown in FIG. 1, the temperature of the exhaust gas from the steelmaking arc furnace 1 fluctuates, but the exhaust gas temperature decreases from the time when the steel is discharged until the start of energization of the next heat. It is preferable to shift the operation time of each steelmaking arc furnace 1 so that low temperature periods with low exhaust gas temperatures from each steelmaking arc furnace 1 appear alternately.
That is, the energization start time and the steel output start time may be determined in advance so that the low temperature periods of each steelmaking arc furnace 1 appear alternately. In short, in the case where an N-base steelmaking arc furnace 1 exists, if the heat treatment time is X, the energization start times of the respective steelmaking arc furnaces 1 are sequentially shifted at intervals of X / N. Just go. However, it is not necessary to accurately shift at an X / N interval, and it is sufficient to have a margin of about 10 minutes before and after. In addition, as the number of arc furnaces 1 for steel making increases, the leveling of steam becomes easier. From this viewpoint, the present invention can be applied to an electric furnace steel factory equipped with three or more arc furnaces 1 for steel making. desirable.
As described above, according to the present invention, steam generated by a waste heat boiler installed in each of a plurality of steelmaking arc furnaces 1 is merged into one path, so that each steelmaking arc furnace 1 is a batch type. The amount of saturated steam generated is different, but the operation status is naturally shifted in each steelmaking arc furnace 1, so the amount of saturated steam after merging is independent of each steelmaking arc furnace 1. Therefore, it is leveled compared with the case of recovering steam. In particular, when the steelmaking arc furnace 1 is operated with the operation time shifted intentionally, the amount of saturated steam after merging is further leveled, and this steam can be used effectively.
　本発明を、図３に示す構成で、還元鉄を鉄源として使用する２００トン規模の４基の製鋼用アーク炉に適用した例を以下に説明する。表１に操業条件及び操業結果を示す。
Figure JPOXMLDOC01-appb-T000001
 　製鋼用アーク炉の１ヒートの所要時間は４基の製鋼用アーク炉ともに７０分であり、約１６分の間隔のずれで各製鋼用アーク炉が順次通電開始するように、各製鋼用アーク炉の稼働形態を調整した。その結果、製鋼用アーク炉１基あたりの蒸気発生量は、瞬時値：４２トン／ｈ、１ヒート平均：３３トン／ｈとなり、蒸気発生量は平準化された。
　この飽和蒸気を蒸気アキュムレーターで貯留し、貯留した飽和蒸気を蒸気アキュムレーターの後段に設けた蒸気過熱器で過熱蒸気に変換し、変換した過熱蒸気を蒸気タービン式発電設備に供給して発電した。
　このように、本実施例では蒸気発生量が平準化できたので、安定発電が可能となり蒸気タービン式発電機能力として２８ＭＷを得ることができた。その結果、従来のように事実上不可能であった排ガスの顕熱および燃焼熱のエネルギー回収が可能となったので、電気炉工場における外部購入の電力を大幅に削減することが可能となった。 An example in which the present invention is applied to four 200 ton scale steelmaking arc furnaces using reduced iron as an iron source with the configuration shown in FIG. 3 will be described below. Table 1 shows the operation conditions and operation results.
Figure JPOXMLDOC01-appb-T000001
 The time required for one heat of each steelmaking arc furnace is 70 minutes for all four steelmaking arc furnaces, and each steelmaking arc furnace is sequentially energized at an interval of about 16 minutes. The operation mode was adjusted. As a result, the amount of steam generated per one steelmaking arc furnace was instantaneous value: 42 tons / h, 1 heat average: 33 tons / h, and the amount of steam generated was leveled.
This saturated steam is stored in a steam accumulator, the stored saturated steam is converted into superheated steam with a steam superheater provided at the subsequent stage of the steam accumulator, and the converted superheated steam is supplied to a steam turbine power generation facility to generate electricity. .
Thus, in this example, since the amount of generated steam was leveled, stable power generation was possible, and 28 MW could be obtained as a steam turbine power generation function. As a result, it has become possible to recover the sensible heat and combustion heat of exhaust gas, which was virtually impossible as before, so that it was possible to significantly reduce the power purchased outside the electric furnace factory. .
　本発明によれば、複数の製鋼用アーク炉にそれぞれ設置した廃熱ボイラーで生成される蒸気を１つの経路に合流させるので、それぞれの製鋼用アーク炉はバッチ形式の稼働形態であり、飽和蒸気の発生量は変動するが、それぞれの製鋼用アーク炉で自ずと稼働状況がずれるので、合流後の飽和蒸気の量は、個々の製鋼用アーク炉からそれぞれ独立して蒸気を回収する場合に比較して平準化される。特に、意図的に運転時間をずらして製鋼用アーク炉を稼働させたときには、合流後の飽和蒸気の量はより一層平準化され、この蒸気を有効活用することが可能となる。また、排ガス温度が８００℃以上の温度域に設置するボイラー伝熱管を輻射型伝熱管とした場合には、高温で軟化したスラグやダストの伝熱管への付着が抑制され、また付着しても清掃が容易であり、排ガス顕熱および燃焼熱から飽和蒸気を安定して回収することが実現される。 According to the present invention, steam generated by a waste heat boiler installed in each of a plurality of steelmaking arc furnaces is joined to one path, so that each steelmaking arc furnace is a batch-type operation mode, and saturated steam The amount of generated steam fluctuates, but the operational status of each steelmaking arc furnace naturally shifts, so the amount of saturated steam after merging is compared to the case where steam is collected independently from each steelmaking arc furnace. Leveled. In particular, when the steelmaking arc furnace is operated with the operation time shifted intentionally, the amount of saturated steam after the merging is further leveled, and this steam can be used effectively. In addition, when the boiler heat transfer tube installed in the temperature range where the exhaust gas temperature is 800 ° C. or higher is a radiant heat transfer tube, adhesion of slag and dust softened at a high temperature to the heat transfer tube is suppressed, Cleaning is easy and it is possible to stably recover saturated steam from exhaust gas sensible heat and combustion heat.

Claims (10)

  1. 　複数の製鋼用アーク炉から排出される排ガスの顕熱および燃焼熱を回収するための製鋼用アーク炉の廃熱回収設備であって、それぞれの製鋼用アーク炉に配置された、排ガスの顕熱および燃焼熱を回収する廃熱ボイラーと、廃熱ボイラーで発生した飽和蒸気を合流させて蒸気アキュムレーターに搬送する蒸気搬送経路と、廃熱ボイラーで発生した飽和蒸気を貯留するための蒸気アキュムレーターと、を備えることを特徴とする、製鋼用アーク炉の廃熱回収設備。 Waste heat recovery equipment for a steelmaking arc furnace for recovering sensible heat and combustion heat of exhaust gas discharged from a plurality of steelmaking arc furnaces, and sensible heat of the exhaust gas disposed in each steelmaking arc furnace Waste heat boiler that collects the combustion heat, a steam transfer path that combines saturated steam generated in the waste heat boiler and transports it to the steam accumulator, and a steam accumulator for storing the saturated steam generated in the waste heat boiler And a waste heat recovery facility for an arc furnace for steel making.
  2. 　排ガス温度が８００℃以上の温度域に配置される廃熱ボイラーの伝熱管は輻射型伝熱管であることを特徴とする、請求項１に記載の製鋼用アーク炉の廃熱回収設備。 The waste heat recovery equipment for an arc furnace for steel making according to claim 1, wherein the heat transfer tube of the waste heat boiler disposed in a temperature range where the exhaust gas temperature is 800 ° C or higher is a radiant heat transfer tube.
  3. 　複数の製鋼用アーク炉が、それぞれ運転時間をずらして稼働されることを特徴とする、請求項１または請求項２に記載の製鋼用アーク炉の廃熱回収設備。 The waste heat recovery equipment for a steelmaking arc furnace according to claim 1 or 2, characterized in that the plurality of steelmaking arc furnaces are operated with different operating times.
  4. 　製鋼用アーク炉から排出される排ガスの顕熱および燃焼熱を回収する廃熱ボイラーを、複数の製鋼用アーク炉にそれぞれ設置し、それぞれの製鋼用アーク炉を運転時間をずらして稼働させ、それぞれの廃熱ボイラーで発生する飽和蒸気を合流させ、飽和蒸気を合流することで発生する飽和蒸気の量を平準化させることを特徴とする、製鋼用アーク炉の廃熱回収方法。 Waste heat boilers that recover sensible heat and combustion heat of exhaust gas discharged from steelmaking arc furnaces are installed in multiple steelmaking arc furnaces, and each steelmaking arc furnace is operated at different operating times. A method for recovering waste heat from an arc furnace for steel making, characterized in that saturated steam generated in a waste heat boiler is joined and the amount of saturated steam generated by joining the saturated steam is leveled.
  5. 　排ガス温度が８００℃以上の温度域に配置される廃熱ボイラーの伝熱管は輻射型伝熱管であることを特徴とする、請求項４に記載の製鋼用アーク炉の廃熱回収方法。 The waste heat recovery method for a steel arc furnace according to claim 4, wherein the heat transfer tube of the waste heat boiler disposed in a temperature range where the exhaust gas temperature is 800 ° C or higher is a radiant heat transfer tube.
  6. 　複数の製鋼用アーク炉からの排ガス温度の低い期間が交互に出現するように、それぞれの製鋼用アーク炉の運転時間をずらすことを特徴とする、請求項４に記載の製鋼用アーク炉の廃熱回収方法。 5. The scrap of the steelmaking arc furnace according to claim 4, wherein the operation time of each steelmaking arc furnace is shifted so that periods of low exhaust gas temperatures from a plurality of steelmaking arc furnaces appear alternately. Heat recovery method.
  7. 　複数の製鋼用アーク炉からの排ガス温度の低い期間が交互に出現するように、それぞれの製鋼用アーク炉の運転時間をずらすことを特徴とする、請求項５に記載の製鋼用アーク炉の廃熱回収方法。 The waste of the steelmaking arc furnace according to claim 5, wherein the operation time of each steelmaking arc furnace is shifted so that periods of low exhaust gas temperatures from a plurality of steelmaking arc furnaces appear alternately. Heat recovery method.
  8. 　それぞれの廃熱ボイラーで発生する飽和蒸気を合流させた後の飽和蒸気を蒸気アキュムレーターに貯留することを特徴とする、請求項４ないし請求項７の何れか１つに記載の製鋼用アーク炉の廃熱回収方法。 The steelmaking arc furnace according to any one of claims 4 to 7, wherein the saturated steam after the saturated steam generated in each waste heat boiler is merged is stored in a steam accumulator. Waste heat recovery method.
  9. 　複数の製鋼用アーク炉の排ガスを廃熱ボイラーの下流側で１つに合流させ、合流させた排ガスの顕熱回収するための過熱器を設置し、該過熱器により、廃熱ボイラーで発生した飽和蒸気を過熱蒸気に変換することを特徴とする、請求項４ないし請求項７の何れか１つに記載の製鋼用アーク炉の廃熱回収方法。 A plurality of steel furnace arc furnace exhaust gases are combined into one on the downstream side of the waste heat boiler, and a superheater is installed to recover the sensible heat of the combined exhaust gas, and the superheater generates the waste heat boiler. The method for recovering waste heat of an arc furnace for steel making according to any one of claims 4 to 7, wherein saturated steam is converted into superheated steam.
  10. 　複数の製鋼用アーク炉の排ガスを廃熱ボイラーの下流側で１つに合流させ、合流させた排ガスの顕熱を回収するための過熱器を設置し、該過熱器により、廃熱ボイラーで発生した飽和蒸気を過熱蒸気に変換することを特徴とする、請求項８に記載の製鋼用アーク炉の廃熱回収方法。 A superheater is installed to recover the sensible heat of the combined exhaust gas from the exhaust gas from multiple steelmaking arc furnaces on the downstream side of the waste heat boiler, and generated in the waste heat boiler by the superheater. The method for recovering waste heat of an arc furnace for steel making according to claim 8, wherein the saturated steam is converted into superheated steam.
PCT/JP2008/073267 2008-10-21 2008-12-16 Waste heat recovery facility of arc furnace for steel-making and method for recovering waste heat WO2010047004A1 (en)

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CN102337374A (en) * 2010-07-21 2012-02-01 盐城市锅炉制造有限公司 Oxygen top-blown converter flue gas purification and waste heat recovery system device
CN102564147A (en) * 2012-02-29 2012-07-11 南京凯盛开能环保能源有限公司 Combined recycling system for fume waste heat of furnace cover and flue of iron alloy electric furnace
CN102914173A (en) * 2012-11-16 2013-02-06 宁夏光合能源科技有限公司 Method and device for recovering and storing ferroalloy furnace molten iron waste heat to generate electricity
CN103063042A (en) * 2013-01-08 2013-04-24 北京世纪源博科技股份有限公司 Method for adjusting ISP (imperial smelting process) cooling chute waste heat boiler and power generation system
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JP2014184625A (en) * 2013-03-22 2014-10-02 Kobe Steel Ltd Exhaust heat utilization device of kneader and exhaust heat utilization method of kneader
CN104868654A (en) * 2015-05-25 2015-08-26 成都中冶节能环保工程有限公司 Boost type waste heat power generation system based on submerged arc furnace
CN104868653A (en) * 2015-05-25 2015-08-26 成都中冶节能环保工程有限公司 Voltage stabilization type waste heat power generation system based on submerged arc furnace
CN104880085A (en) * 2015-05-25 2015-09-02 成都中冶节能环保工程有限公司 Alarm voltage stabilizing type waste heat power generation system based on submerged arc furnace
CN105036077A (en) * 2015-08-07 2015-11-11 北京神雾环境能源科技集团股份有限公司 Method and system for recovering waste heat of syngas obtained by partial oxidation of natural gas
CN105180664A (en) * 2015-07-16 2015-12-23 中国中元国际工程有限公司 Waste-heat utilization device of intermittent steelmaking electric-arc furnace and waste-heat utilization method for waste-heat utilization device
CN106152804A (en) * 2016-07-12 2016-11-23 中南大学 A kind of horizontal carbon shirt-circuiting furnace waste gas afterheat recovery system and using method thereof
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WO2011132669A1 (en) * 2010-04-20 2011-10-27 スチールプランテック株式会社 Waste heat recovery facility for arc furnace for steel making, arc furnace facility for steel making, and waste heat recovery method for arc furnace for steel making
CN102337374A (en) * 2010-07-21 2012-02-01 盐城市锅炉制造有限公司 Oxygen top-blown converter flue gas purification and waste heat recovery system device
CN102564147A (en) * 2012-02-29 2012-07-11 南京凯盛开能环保能源有限公司 Combined recycling system for fume waste heat of furnace cover and flue of iron alloy electric furnace
CN102914173A (en) * 2012-11-16 2013-02-06 宁夏光合能源科技有限公司 Method and device for recovering and storing ferroalloy furnace molten iron waste heat to generate electricity
CN103063042A (en) * 2013-01-08 2013-04-24 北京世纪源博科技股份有限公司 Method for adjusting ISP (imperial smelting process) cooling chute waste heat boiler and power generation system
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CN103063042B (en) * 2013-01-08 2014-09-10 北京世纪源博科技股份有限公司 Method for adjusting ISP (imperial smelting process) cooling chute waste heat boiler and power generation system
JP2014184625A (en) * 2013-03-22 2014-10-02 Kobe Steel Ltd Exhaust heat utilization device of kneader and exhaust heat utilization method of kneader
CN103256825B (en) * 2013-05-24 2014-11-05 北京工业大学 Method for monitoring cement production soot emission and waste heat power generation system soot emission
CN103256825A (en) * 2013-05-24 2013-08-21 北京工业大学 Method for monitoring cement production soot emission and waste heat power generation system soot emission
CN103453777A (en) * 2013-08-29 2013-12-18 宁夏天纵泓光余热发电技术有限公司 Smoke residual heat power generating system
CN104868654A (en) * 2015-05-25 2015-08-26 成都中冶节能环保工程有限公司 Boost type waste heat power generation system based on submerged arc furnace
CN104868653A (en) * 2015-05-25 2015-08-26 成都中冶节能环保工程有限公司 Voltage stabilization type waste heat power generation system based on submerged arc furnace
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