JP6699629B2 - Operation method of oxygen blast furnace - Google Patents
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- JP6699629B2 JP6699629B2 JP2017125935A JP2017125935A JP6699629B2 JP 6699629 B2 JP6699629 B2 JP 6699629B2 JP 2017125935 A JP2017125935 A JP 2017125935A JP 2017125935 A JP2017125935 A JP 2017125935A JP 6699629 B2 JP6699629 B2 JP 6699629B2
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims description 69
- 239000001301 oxygen Substances 0.000 title claims description 69
- 229910052760 oxygen Inorganic materials 0.000 title claims description 69
- 238000000034 method Methods 0.000 title claims description 9
- 238000001514 detection method Methods 0.000 claims description 28
- 239000000446 fuel Substances 0.000 claims description 24
- 239000004449 solid propellant Substances 0.000 claims description 17
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 10
- 238000011017 operating method Methods 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 239000007789 gas Substances 0.000 description 30
- 238000012360 testing method Methods 0.000 description 16
- 238000007664 blowing Methods 0.000 description 14
- 239000003245 coal Substances 0.000 description 13
- 238000002485 combustion reaction Methods 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 8
- 230000005855 radiation Effects 0.000 description 8
- 238000005070 sampling Methods 0.000 description 6
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 4
- 239000006227 byproduct Substances 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000002803 fossil fuel Substances 0.000 description 2
- 239000013307 optical fiber Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000012795 verification Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000036760 body temperature Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- Manufacture Of Iron (AREA)
Description
本発明は、酸素または酸素富化空気と、気体燃料および／または固体燃料とを羽口から高炉内へ供給して操業する酸素高炉における逆火の検知方法および酸素高炉の操業方法に関する。 The present invention relates to a method of detecting flashback in an oxygen blast furnace that operates by supplying oxygen or oxygen-enriched air and gaseous fuel and/or solid fuel into a blast furnace from a tuyere, and an operation method of the oxygen blast furnace.
近年、地球環境問題を背景として、製鉄所においても省エネ、省資源、炭酸ガス（ＣＯ２）発生抑制が強く要求されている。これを受け、最近の高炉操業では低還元材比（低ＲＡＲ）操業が強力に推進されている。従来の高炉では羽口から熱風を吹き込んでいた。熱風を作り出す熱源として、高炉、コークス炉、転炉から発生する副生ガスの混合ガス（Ｍガス）が使用されるが、熱風の持つ熱量分高炉に必要な還元材比は低減されていた。従来の高炉で使用されている還元材は炭素を主成分とする化石燃料で構成されることから、熱風送風はその化石燃料の使用量およびＣＯ２発生量を抑制してきたともいえる。 In recent years, against the backdrop of global environmental problems, energy saving, resource saving, and suppression of carbon dioxide (CO 2 ) generation have been strongly demanded in steelworks as well. In response to this, a low reducing agent ratio (low RAR) operation has been strongly promoted in the recent blast furnace operation. In the conventional blast furnace, hot air was blown from the tuyere. As a heat source for producing hot air, a mixed gas (M gas) of by-product gas generated from a blast furnace, a coke oven, and a converter is used, but the reducing material ratio required for the blast furnace has been reduced by the amount of heat of hot air. Since the reducing agent used in the conventional blast furnace is composed of fossil fuel containing carbon as the main component, it can be said that the hot air blowing has suppressed the usage amount of the fossil fuel and the CO 2 generation amount.
一方、羽口から熱風を吹き込まず、常温純酸素を吹き込むことで溶銑を製造する酸素高炉が特許文献１に開示されている。酸素高炉は、窒素レスのため高出銑比となり、炉頂から高カロリーの副生ガスが得られるといった利点に加え、高濃度の酸素の使用により微粉炭の燃焼速度が上昇するので羽口から吹き込む微粉炭の量を増やすことができるという利点もある。 On the other hand, Patent Document 1 discloses an oxygen blast furnace that produces hot metal by blowing pure oxygen at room temperature without blowing hot air from the tuyere. The oxygen blast furnace has a high tap ratio because it does not contain nitrogen, and in addition to the advantage that a high-calorie by-product gas can be obtained from the furnace top, the burning rate of pulverized coal increases due to the use of high-concentration oxygen, There is also an advantage that the amount of pulverized coal to be blown can be increased.
しかしながら、酸素富化高炉もしくは酸素高炉では、羽口内における微粉炭の燃焼、いわゆる逆火現象が発生する。これは、高濃度酸素による燃焼性の向上と、通常の熱風高炉と比べて吹き込みガス流量が減少するので、火炎伝搬速度がガス流速より大きくなってしまうことに起因すると考えられる。特許文献２には、その逆火現象の対策として羽口先からの吹き出しガス流速を１０５ｍ／ｓ以上にすることが開示されている。 However, in the oxygen-rich blast furnace or the oxygen blast furnace, combustion of pulverized coal in the tuyere, so-called flashback phenomenon occurs. It is considered that this is because the combustibility is improved by the high-concentration oxygen and the blown gas flow rate is reduced as compared with the normal hot air blast furnace, so that the flame propagation velocity becomes higher than the gas flow velocity. Patent Document 2 discloses that, as a countermeasure against the flashback phenomenon, the flow velocity of the gas blown from the tuyere is set to 105 m/s or more.
しかしながら、高炉内部の圧力変動、ガスの供給圧力の変動、微粉炭搬送のトラブル等で、ガス流速が１０５ｍ／ｓより遅くなり、逆火が発生する場合がある。また、羽口から気体燃料を供給する場合には固体燃料よりも燃焼性が向上するので、羽口先からの吹き出しガス流速を１０５ｍ／ｓ以上にしても逆火が発生する場合がある。羽口内における逆火が頻発あるいは継続すると羽口内における圧力変動等により機械的な衝撃が生じ、羽口設備が破損する、という課題があった。本発明は、このような従来技術を鑑みてなされたものであり、その目的とするところは、酸素高炉における羽口内の逆火の発生を早期に検知できる逆火の検知方法を提供することにある。 However, due to pressure fluctuations inside the blast furnace, fluctuations in gas supply pressure, troubles in pulverized coal transportation, etc., the gas flow velocity may become slower than 105 m/s, and flashback may occur. Further, when the gaseous fuel is supplied from the tuyere, the combustibility is improved as compared with the solid fuel, and therefore a flashback may occur even if the gas flow velocity from the tuyere is 105 m/s or more. If backfire occurs frequently or continues in the tuyere, mechanical shock occurs due to pressure fluctuations in the tuyere, and the tuyere equipment is damaged. The present invention has been made in view of such conventional techniques, and an object of the present invention is to provide a flashback detection method capable of early detecting the occurrence of flashback in the tuyeres of an oxygen blast furnace. is there.
このような課題を解決するための本発明の特徴は、以下の通りである。
（１）酸素または酸素を５０体積％以上含む酸素富化空気と、気体燃料および／または固体燃料とを、羽口から高炉内へ供給して操業する酸素高炉における逆火の検知方法であって、前記羽口内で発生した逆火によって生じる現象を検出して、前記羽口内で逆火が発生したことを検知する、逆火の検知方法。
（２）前記現象は、前記逆火による温度の上昇であり、前記羽口内の温度を測定し、前記羽口内の温度が予め定められた閾値以上に上昇した場合に、前記羽口内で逆火が発生したことを検知する、（１）に記載の逆火の検知方法。
（３）前記現象は、前記逆火からの光の放射であり、前記羽口内の光の強度を測定し、測定された光の強度が予め定められた閾値以上になった場合に、前記羽口内で逆火が発生したことを検知する、（１）に記載の逆火の検知方法。
（４）（１）から（３）の何れか１つに記載の逆火の検知方法で、前記羽口内の逆火が検知された場合に、前記気体燃料および固体燃料の供給を停止する、酸素高炉の操業方法。
（５）空気に酸素を供給して酸素を５０体積％以上含む酸素富化空気とする場合には、
さらに空気への酸素の供給を停止する、（４）に記載の酸素高炉の操業方法。
（６）気体燃料の供給を停止する場合において、停止した気体燃料を供給するラインから窒素を供給する、（４）または（５）に記載の酸素高炉の操業方法。
The features of the present invention for solving such a problem are as follows.
(1) A method for detecting flashback in an oxygen blast furnace in which oxygen or oxygen-enriched air containing 50% by volume or more of oxygen, a gaseous fuel and/or a solid fuel is supplied from a tuyere into the blast furnace to operate. A method for detecting flashback, which detects a phenomenon caused by a flashback occurring in the tuyere and detects that a flashback occurs in the tuyere.
(2) The phenomenon is an increase in temperature due to the flashback. When the temperature in the tuyere is measured and the temperature in the tuyere rises above a predetermined threshold value, the flashback occurs in the tuyere. The method of detecting a flashback according to (1), which detects that the occurrence of fire.
(3) The phenomenon is the emission of light from the flashback, the intensity of the light in the tuyere is measured, and when the measured intensity of light is equal to or greater than a predetermined threshold value, the wing The flashback detection method according to (1), which detects that a flashback has occurred in the mouth.
(4) In the method of detecting a flashback according to any one of (1) to (3), when the flashback in the tuyere is detected, the supply of the gaseous fuel and the solid fuel is stopped. Operating method of oxygen blast furnace.
(5) When oxygen is supplied to air to obtain oxygen-enriched air containing 50% by volume or more of oxygen,
Further, the operating method of the oxygen blast furnace according to (4), wherein the supply of oxygen to the air is stopped.
(6) The method for operating an oxygen blast furnace according to (4) or (5), wherein when the supply of the gaseous fuel is stopped, nitrogen is supplied from a line for supplying the stopped gaseous fuel.
本発明に係る逆火の検知方法により、羽口内における逆火の発生を早期に検知できる。これにより、羽口内の逆火が継続しないように対策をとることができるので、逆火発生による羽口設備への影響を少なくできる。そのため、たとえば羽口へ酸素や燃料を供給するバーナーを水冷する必要がなくなり、羽口周辺の設備の複雑化を回避できる。 The flashback detection method according to the present invention enables early detection of flashback in tuyere. As a result, measures can be taken so that the flashback in the tuyere does not continue, so that the effect on the tuyere equipment due to the occurrence of flashback can be reduced. Therefore, for example, it is not necessary to water-cool the burner that supplies oxygen and fuel to the tuyere, and it is possible to avoid complication of the equipment around the tuyere.
本発明の実施形態を通じて本発明を説明する。図１は、本実施形態に係る逆火の検知方法に用いられる逆火検知装置を備える羽口設備の部分断面模式図である。羽口設備１０は、バーナー１２と、羽口１４と、制御弁１６と、逆火検知装置１８と、を備える。 The present invention will be described through embodiments of the present invention. FIG. 1 is a schematic partial cross-sectional view of tuyere equipment including a flashback detection device used in the flashback detection method according to the present embodiment. The tuyere equipment 10 includes a burner 12, a tuyere 14, a control valve 16, and a flashback detection device 18.
バーナー１２は、羽口１４に内包されるように接続される。バーナー１２から羽口１４に、酸素富化空気２０、気体燃料２２、固体燃料２４が供給される。気体燃料としては、例えば、都市ガス、プロパンガス、製鉄所内で発生した副生ガスが利用できる。これらガスを適宜混合して使用することも可能である。固体燃料としては、例えば、微粉炭、廃プラスチックである。また、酸素富化空気とは、酸素を５０体積％以上含むように酸素富化された空気である。あるいは純酸素を吹込むこともある。バーナー１２から純酸素もしくは酸素富化空気を羽口から吹込むことで、酸素高炉もしくは酸素富化高炉の操業が実現できる。なお、以後の説明において、純酸素を吹込む酸素高炉および酸素富化空気を吹込む酸素富化高炉ともに酸素高炉と記載する。 The burner 12 is connected so as to be contained in the tuyere 14. Oxygen-enriched air 20, gaseous fuel 22, and solid fuel 24 are supplied from the burner 12 to the tuyere 14. As the gaseous fuel, for example, city gas, propane gas, and by-product gas generated in the steel mill can be used. It is also possible to appropriately mix and use these gases. Examples of the solid fuel include pulverized coal and waste plastic. The oxygen-enriched air is air enriched with oxygen so as to contain 50% by volume or more of oxygen. Alternatively, pure oxygen may be blown in. By blowing pure oxygen or oxygen-enriched air from the burner 12 through the tuyere, the operation of the oxygen blast furnace or the oxygen-enriched blast furnace can be realized. In the following description, the oxygen blast furnace that blows pure oxygen and the oxygen-rich blast furnace that blows oxygen-enriched air are both referred to as oxygen blast furnaces.
バーナー１２から供給された酸素富化空気２０の酸素、気体燃料２２および固体燃料２４は、羽口１４を通過した後の炉内で燃焼する。このように、羽口１４で燃焼せずに、炉内で燃焼する状態を正常状態と定義する。一方、バーナー１２から供給された酸素富化空気２０の酸素、気体燃料２２および固体燃料２４が、羽口１４内で燃焼する場合がある。この羽口１４内の燃焼を逆火と定義する。逆火が発生し、当該逆火が５秒以上継続すると、微粉炭による摩耗防止のために羽口１４の内面に取り付けたライナー等が破損し、さらに、逆火が継続すると、羽口設備１０が破損するおそれが生じる。このため、羽口１４内の逆火の発生を早期に検知して、羽口１４内の逆火を鎮火させることが好ましい。 The oxygen, the gaseous fuel 22, and the solid fuel 24 of the oxygen-enriched air 20 supplied from the burner 12 burn in the furnace after passing through the tuyere 14. In this way, a state in which the tuyere 14 does not burn but burns in the furnace is defined as a normal state. On the other hand, the oxygen of the oxygen-enriched air 20 supplied from the burner 12, the gaseous fuel 22, and the solid fuel 24 may burn in the tuyere 14. The combustion in the tuyere 14 is defined as flashback. If a flashback occurs and the flashback continues for 5 seconds or more, the liner or the like attached to the inner surface of the tuyere 14 to prevent wear due to pulverized coal is damaged, and if the flashback continues, the tuyere equipment 10 May be damaged. Therefore, it is preferable to detect the occurrence of the flashback in the tuyere 14 at an early stage to extinguish the flashback in the tuyere 14.
制御弁１６は、バーナー１２への酸素富化空気２０、気体燃料２２および固体燃料２４の供給を制御する。また、制御弁１６は、酸素富化空気２０を生成するための空気への酸素の供給を制御する。さらに、制御弁１６は、気体燃料２２の供給ラインへの窒素の供給を制御する。 The control valve 16 controls the supply of the oxygen-enriched air 20, the gaseous fuel 22, and the solid fuel 24 to the burner 12. The control valve 16 also controls the supply of oxygen to the air for producing the oxygen-enriched air 20. Further, the control valve 16 controls the supply of nitrogen to the supply line of the gaseous fuel 22.
逆火検知装置１８は、羽口１４内における逆火の発生によって生じる現象を検出して羽口内で逆火が発生したことを検知する。本実施形態において、逆火検知装置１８は、逆火の発生によって生じる現象の一つである羽口１４内の温度の上昇から羽口１４内の逆火の発生を検知する。 The flashback detection device 18 detects a phenomenon caused by the occurrence of the flashback in the tuyere 14 and detects the occurrence of the flashback in the tuyere. In the present embodiment, the flashback detection device 18 detects the occurrence of flashback in the tuyere 14 from the rise in the temperature in the tuyere 14, which is one of the phenomena caused by the occurrence of flashback.
逆火検知装置１８は、熱電対３０と、制御装置３２とを有する。熱電対３０の測温接点は、例えば、羽口１４とバーナー１２の接続部から羽口１４側に３０ｍｍとなる位置に設けられる。測温接点の位置を羽口１４の先端の近くにすると、炉内の高温による影響を受けやすく誤検知が多くなり、また熱電対３０の羽口１４内での施工長さが長くなり、羽口１４の加工が難しくなるので好ましくない。羽口１４の大きさにもよるが、測温接点の位置は、羽口１４とバーナーの接続部から羽口側に１５０ｍｍ以下の位置に設置することが好ましい。また熱電対３０の測温接点は、炉内からの輻射が直接当たらないような位置に設置することが好ましい。熱電対３０は、羽口１４内の温度を測定して、測定した温度を制御装置３２に出力する。 The flashback detection device 18 includes a thermocouple 30 and a control device 32. The temperature measuring contact of the thermocouple 30 is provided, for example, at a position of 30 mm from the connecting portion between the tuyere 14 and the burner 12 toward the tuyere 14 side. If the position of the temperature measuring contact is located near the tip of the tuyere 14, it will be easily affected by the high temperature in the furnace and false detection will increase, and the construction length of the thermocouple 30 in the tuyere 14 will become long, and It is not preferable because the processing of the mouth 14 becomes difficult. Although it depends on the size of the tuyere 14, it is preferable that the position of the temperature measuring contact is set at a position of 150 mm or less from the connecting portion of the tuyere 14 and the burner to the tuyere side. Further, the temperature measuring contact of the thermocouple 30 is preferably installed at a position where radiation from the inside of the furnace is not directly applied. The thermocouple 30 measures the temperature inside the tuyere 14 and outputs the measured temperature to the control device 32.
制御装置３２は、例えば、制御部３４と格納部３６とを有するワークステーションやパソコン等の汎用コンピュータである。制御部３４は、例えば、ＣＰＵ等であって、格納部３６に保存されたプログラムやデータを用いて、熱電対３０や制御弁１６の動作を制御する。格納部３６には、熱電対３０および制御弁１６が有する機能を実現するためのプログラムや、当該プログラム実行中に使用するデータ等が予め格納されている。また、格納部３６には、逆火の発生を検出するために用いる閾値も格納されている。 The control device 32 is a general-purpose computer such as a workstation or a personal computer having a control unit 34 and a storage unit 36, for example. The control unit 34 is, for example, a CPU or the like, and controls the operation of the thermocouple 30 and the control valve 16 using the programs and data stored in the storage unit 36. The storage unit 36 stores in advance a program for realizing the functions of the thermocouple 30 and the control valve 16, data used during execution of the program, and the like. The storage unit 36 also stores a threshold value used for detecting the occurrence of flashback.
熱電対３０は、制御部３４の制御により、例えば、２秒ごとに羽口１４内の温度を測定し、測定した温度を制御部３４に出力する。制御部３４は、熱電対３０から温度を取得すると、格納部３６に格納された閾値を読み出す。制御部３４は、熱電対３０から出力された温度と閾値とを比較し、熱電対３０から出力された温度が、当該閾値以上であるか否かを判断する。制御部３４は、熱電対３０から出力された温度が閾値以上であることを検出した場合に羽口１４内で逆火が発生したと判断する。一方、制御部３４は、熱電対３０から出力された温度が閾値以上であることを検出しない、すなわち、熱電対３０から出力された温度が閾値より低い場合には、羽口１４内で逆火が発生していないと判断する。 Under the control of the control unit 34, the thermocouple 30 measures the temperature inside the tuyere 14 every two seconds, for example, and outputs the measured temperature to the control unit 34. When the control unit 34 acquires the temperature from the thermocouple 30, the control unit 34 reads the threshold value stored in the storage unit 36. The control unit 34 compares the temperature output from the thermocouple 30 with a threshold value and determines whether the temperature output from the thermocouple 30 is equal to or higher than the threshold value. The control unit 34 determines that a flashback has occurred in the tuyere 14 when detecting that the temperature output from the thermocouple 30 is equal to or higher than the threshold value. On the other hand, the control unit 34 does not detect that the temperature output from the thermocouple 30 is equal to or higher than the threshold value, that is, when the temperature output from the thermocouple 30 is lower than the threshold value, the flashback occurs in the tuyere 14. Is determined not to occur.
逆火が発生していない羽口１４内の温度は、常温の酸素富化空気２０が供給されることによって冷却され、３０℃以下になる。一方、羽口１４内で逆火が発生すると羽口１４内の温度は数秒で５００℃以上に上昇する。したがって、閾値を、例えば、２００〜４００℃の範囲内の温度とし、熱電対３０を用いて２秒ごとに羽口１４の温度を測定し、羽口１４内の温度が当該閾値以上になったことを制御部３４で検出することで、羽口１４内における逆火の発生を早期に検知できる。検出速度を上げるためには羽口１４内の温度のサンプリング周期を２秒よりも短くすることが好ましいが、例えば、サンプリング周期を０．５秒とした場合にはデータ量は４倍となり、制御装置３２への負荷が大きくなるというデメリットも発生する。高炉の実操業は２４時間操業であり、更に大型高炉における羽口数は４０本程度が主流であるので、全操業時間における全羽口のサンプリングデータは膨大な量になる。 The temperature in the tuyere 14 where the flashback does not occur is cooled by supplying the oxygen-enriched air 20 at room temperature, and becomes 30° C. or less. On the other hand, when a flashback occurs in the tuyere 14, the temperature in the tuyere 14 rises to 500° C. or higher in a few seconds. Therefore, the threshold is set to, for example, a temperature in the range of 200 to 400° C., the temperature of the tuyere 14 is measured every two seconds using the thermocouple 30, and the temperature in the tuyere 14 becomes equal to or higher than the threshold. By detecting this by the control unit 34, the occurrence of flashback in the tuyere 14 can be detected at an early stage. In order to increase the detection speed, it is preferable to make the sampling cycle of the temperature in the tuyere 14 shorter than 2 seconds. For example, when the sampling cycle is 0.5 seconds, the data amount becomes 4 times, There is also a demerit that the load on the device 32 becomes large. Since the actual operation of the blast furnace is 24 hours, and the number of tuyere in the large blast furnace is about 40, the sampling data of all the tuyere for the entire operation time is enormous.
サンプリング周期は、制御装置３２のデータ処理能力により決定されるが、サンプリング周期が長くなりすぎると、例えば、ライナー破損となる５秒以上の逆火継続を判定することが困難になる。誤検知を防ぐためには、連続する２点以上の温度が閾値以上になったことを条件に逆火の発生を検知することが好ましいことから、羽口１４内の温度のサンプリング周期は、２秒程度とすることが好ましい。 The sampling period is determined by the data processing capability of the control device 32. However, if the sampling period is too long, it will be difficult to determine, for example, a flashback duration of 5 seconds or more, which causes liner failure. In order to prevent erroneous detection, it is preferable to detect the occurrence of flashback on the condition that the temperature at two or more consecutive points becomes equal to or higher than the threshold value. Therefore, the sampling cycle of the temperature in the tuyere 14 is 2 seconds. It is preferable to set it to a degree.
また、逆火が発生したことを検知すると、制御部３４は、制御弁１６に気体燃料２２および固体燃料２４の供給を停止させる。これにより、羽口１４内への燃料の供給が停止されるので羽口１４内の逆火を鎮火でき、この結果、羽口設備１０の破損を防止できる。 When detecting the occurrence of flashback, the control unit 34 causes the control valve 16 to stop the supply of the gaseous fuel 22 and the solid fuel 24. As a result, the fuel supply to the tuyere 14 is stopped, so that the flashback in the tuyere 14 can be extinguished, and as a result, damage to the tuyere equipment 10 can be prevented.
また、制御部３４は、制御弁１６に気体燃料２２および固体燃料２４の供給を停止させるとともに、空気への酸素の供給を停止させてもよい。これにより、酸素富化空気の酸素濃度が低下するので、羽口１４内の逆火をより早く鎮火できる。 Further, the control unit 34 may stop the supply of the gaseous fuel 22 and the solid fuel 24 to the control valve 16 and also stop the supply of oxygen to the air. As a result, the oxygen concentration of the oxygen-enriched air decreases, so that the flashback in the tuyere 14 can be extinguished more quickly.
さらに、制御部３４は、制御弁１６に気体燃料２２および固体燃料２４の供給を停止させるとともに、気体燃料２２の供給ラインから窒素を羽口１４内に供給してもよい。これにより、酸素富化空気の酸素濃度はさらに低下するので、羽口１４内の逆火をさらに早く鎮火できる。 Further, the control unit 34 may stop the supply of the gaseous fuel 22 and the solid fuel 24 to the control valve 16 and may supply nitrogen into the tuyere 14 from the supply line of the gaseous fuel 22. As a result, the oxygen concentration of the oxygen-enriched air is further reduced, so that the flashback in the tuyere 14 can be extinguished more quickly.
このように、本実施形態に係る逆火の検知方法を実施することで、羽口１４内の逆火の発生を早期に検知できる。そして、羽口１４内の逆火が継続しないように上記対策をとることで、酸素高炉の操業で逆火が発生したとしても羽口設備１０への影響を少なくできる。 As described above, by implementing the flashback detection method according to the present embodiment, the occurrence of flashback in the tuyere 14 can be detected at an early stage. Then, by taking the above measures so that the flashback in the tuyere 14 does not continue, even if the flashback occurs in the operation of the oxygen blast furnace, the influence on the tuyere equipment 10 can be reduced.
なお、本実施形態においては、熱電対３０を用いて羽口１４内の温度を測定する例を示したがこれに限らない。熱電対３０に代えて、放射温度計を用いて羽口１４内の温度を測定してもよい。放射温度計を使用する場合は、羽口内に光ファイバーを設置し、炉体の外部に設置した放射温度計が、この光ファイバーを通して羽口内の温度を測定するように構成することもできる。放射温度計を用いて羽口内の温度を測定する場合は、放射温度計の測温視野に羽口前の炉内が入らないように設置することが好ましい。 In addition, in this embodiment, the example which measures the temperature in the tuyere 14 using the thermocouple 30 was shown, but it is not restricted to this. Instead of the thermocouple 30, a radiation thermometer may be used to measure the temperature inside the tuyere 14. When the radiation thermometer is used, an optical fiber may be installed in the tuyere, and the radiation thermometer installed outside the furnace body may be configured to measure the temperature in the tuyere through the optical fiber. When the temperature inside the tuyere is measured using the radiation thermometer, it is preferable to install the radiation thermometer so that the inside of the furnace in front of the tuyere does not enter the field of view of the temperature.
また、本実施形態では、逆火の発生によって生じる現象の一つとして、逆火による温度の上昇を検出することで逆火を検知する例を示したが、これに限らない。逆火の発生によって生じる現象として、例えば、逆火からの光の放射を検出してもよい。図２は、本実施形態に係る別の逆火の検知方法に用いられる別の逆火検知装置を備える羽口設備の部分断面模式図である。なお、図２において、図１と同じ構成には同じ参照番号を付して重複する説明を省略する。図２に示した羽口設備４０は、ＵＶセンサ４４を有する逆火検知装置４２を備える点において、図１に示した羽口設備１０と異なる。 Further, in the present embodiment, as an example of the phenomenon caused by the occurrence of flashback, an example in which the flashback is detected by detecting an increase in temperature due to flashback has been shown, but the invention is not limited to this. As a phenomenon caused by the occurrence of flashback, for example, light emission from the flashback may be detected. FIG. 2 is a schematic partial cross-sectional view of tuyere equipment including another flashback detection device used in another flashback detection method according to the present embodiment. In FIG. 2, the same components as those in FIG. 1 are designated by the same reference numerals, and overlapping description will be omitted. The tuyere installation 40 shown in FIG. 2 differs from the tuyere installation 10 shown in FIG. 1 in that it includes a flashback detection device 42 having a UV sensor 44.
逆火検知装置４２は、ＵＶセンサ４４と、制御装置３２とを備える。ＵＶセンサ４４は、例えば、羽口１４と、バーナー１２の接続部から羽口１４側に３０ｍｍとなる位置に設けられる。このＵＶセンサ４４の設置位置も、温度測定の場合と同様に考えることができる。ＵＶセンサ４４は、羽口１４内で発生した逆火から放射される紫外光を検知し、紫外光の発光強度に対応した大きさの電気信号（Ｖ）を制御部３４に出力する。 The flashback detection device 42 includes a UV sensor 44 and a control device 32. The UV sensor 44 is provided, for example, at a position of 30 mm from the connecting portion of the tuyere 14 and the burner 12 toward the tuyere 14 side. The installation position of the UV sensor 44 can be considered as in the case of temperature measurement. The UV sensor 44 detects the ultraviolet light emitted from the flashback generated in the tuyere 14, and outputs an electric signal (V) having a magnitude corresponding to the emission intensity of the ultraviolet light to the control unit 34.
制御部３４は、例えば、２秒ごとにＵＶセンサ４４の電気信号を取得する。制御部３４は、電気信号を取得すると、予め格納部３６に格納された電気信号の閾値を読み出す。制御部３４は、ＵＶセンサ４４から出力された電気信号と閾値とを比較し、ＵＶセンサ４４から出力された電気信号が、当該閾値以上であるか否かを判断する。制御部３４は、ＵＶセンサ４４から出力された電気信号が閾値以上であることを検出した場合に羽口１４内で逆火が発生したと判断する。一方、制御部３４は、ＵＶセンサ４４から出力された電気信号が閾値以上であることを検出しない、すなわち、ＵＶセンサ４４から出力された電気信号が閾値より低い場合には、羽口１４内で逆火が発生していないと判断する。 The control unit 34 acquires the electric signal of the UV sensor 44, for example, every 2 seconds. When the control unit 34 acquires the electric signal, the control unit 34 reads the threshold value of the electric signal stored in the storage unit 36 in advance. The control unit 34 compares the electric signal output from the UV sensor 44 with a threshold value, and determines whether the electric signal output from the UV sensor 44 is equal to or more than the threshold value. The control unit 34 determines that a flashback has occurred in the tuyere 14 when detecting that the electric signal output from the UV sensor 44 is equal to or higher than the threshold value. On the other hand, the control unit 34 does not detect that the electric signal output from the UV sensor 44 is equal to or higher than the threshold value, that is, when the electric signal output from the UV sensor 44 is lower than the threshold value, inside the tuyere 14. Judge that no flashback has occurred.
逆火が発生していない羽口１４内の紫外光の放射強さは、ＵＶセンサ４４の出力値で、０．３Ｖ以下になる。一方、羽口１４内で逆火が発生すると羽口１４内の紫外光の放射強さは、ＵＶセンサの出力値で０.７〜１．５Ｖの範囲内の値になる。したがって、閾値を、例えば、０.４〜０．６Ｖの範囲内の値にし、ＵＶセンサ４４から２秒ごとに電気信号を取得し、羽口１４内の紫外光の発光強度に対応した電気信号が閾値以上になったことを制御部３４で検出することで、羽口１４内における逆火の発生を早期に検知できる。 The radiation intensity of the ultraviolet light in the tuyere 14 where the flashback does not occur is 0.3 V or less as the output value of the UV sensor 44. On the other hand, when a flashback occurs in the tuyere 14, the radiation intensity of the ultraviolet light in the tuyere 14 becomes a value within the range of 0.7 to 1.5 V in the output value of the UV sensor. Therefore, for example, the threshold is set to a value within the range of 0.4 to 0.6 V, an electric signal is acquired from the UV sensor 44 every 2 seconds, and the electric signal corresponding to the emission intensity of the ultraviolet light in the tuyere 14 is acquired. The occurrence of flashback in the tuyere 14 can be detected at an early stage by detecting by the control unit 34 that the value has exceeded a threshold value.
このように、逆火の発生によって生じる現象の一つである光の放射から逆火の発生を検知してもよく、これにより、羽口１４内の逆火の発生を早期に検知できる。そして、羽口１４内で発生した逆火が継続しないように上記対策をとることで、逆火発生による羽口設備４０への影響を少なくできる。なお、逆火からは紫外光だけでなく、可視光および赤外光も放射されるので、逆火の発生により紫外光の発光強度とともに可視光および赤外光の発光強度も高くなる。したがって、逆火検知装置４２に設けられるセンサとしては、ＵＶセンサ４４に限らず、可視光および赤外光の発光強度を検知できる光学センサであればよい。 In this way, the occurrence of flashback may be detected from the emission of light, which is one of the phenomena caused by the occurrence of flashback, and thus the occurrence of flashback in the tuyere 14 can be detected early. Then, by taking the above measures so that the flashback generated in the tuyere 14 does not continue, it is possible to reduce the influence of the flashback on the tuyere equipment 40. Since flashback emits not only ultraviolet light but also visible light and infrared light, the occurrence of flashback increases the emission intensity of ultraviolet light as well as the emission intensity of visible light and infrared light. Therefore, the sensor provided in the flashback detection device 42 is not limited to the UV sensor 44, and may be any optical sensor capable of detecting the emission intensity of visible light and infrared light.
高炉の羽口部を模したオフライン試験設備を用いて本実施形態に係る逆火の検知方法の検証実験を行った。実施例１の試験条件と試験結果を表１に示す。実施例１で用いたオフライン試験設備は、図１に示した羽口設備１０と同じ設備が、炉口２０００ｍｍの燃焼炉体（以後、炉体と記載する）に設けられた設備である。オフライン試験設備において、図１に示した羽口内の位置と炉体内とに熱電対を設けた。これら熱電対を用いて、２秒ごとに羽口内および炉体内の温度を測定した。 A verification experiment of the flashback detection method according to the present embodiment was conducted using an off-line test facility imitating the tuyere of a blast furnace. Table 1 shows the test conditions and test results of Example 1. The offline test facility used in Example 1 is the same facility as the tuyere facility 10 shown in FIG. 1 provided in a combustion furnace body with a furnace mouth of 2000 mm (hereinafter referred to as a furnace body). In the off-line test facility, thermocouples were provided inside the tuyere and inside the furnace shown in FIG. Using these thermocouples, the temperature inside the tuyere and inside the furnace was measured every 2 seconds.
実施例１で用いた羽口設備では、逆火を検知する羽口内の温度の閾値を３００℃とした。なお、実施例１は、逆火を検知できるか否かを検証する実験であるので、制御部は、仮に逆火を検知しても都市ガスおよび微粉炭のバーナーへの供給を停止しない。 In the tuyere equipment used in Example 1, the temperature threshold in the tuyere for detecting flashback was 300°C. Since the first embodiment is an experiment for verifying whether or not a flashback can be detected, the control unit does not stop the supply of city gas and pulverized coal to the burner even if the flashback is detected.
また、実施例１では２種類のバーナーを用いた。形状Ａのバーナーおよび形状Ｂのバーナーともに、外側から中心に向かって酸素供給管、都市ガス供給管、微粉炭供給管の順に環状に設けられている点は共通するが、形状Ａのバーナーは、都市ガスを供給する直径２ｍｍの管が８個設けられているのに対し、形状Ｂのバーナーは、都市ガスを供給する直径３ｍｍの管が１６個設けられている。形状Ａのバーナーにおける都市ガスの吹き出し口の断面積は、形状Ｂの吹き出し口の断面積の１／４．５となっている。このため、仮に都市ガス流量が同じであってとしても形状Ａのバーナーの都市ガス流速は、形状Ｂのバーナーの都市ガス流速より４．５倍速くなる。 Further, in Example 1, two types of burners were used. Both the shape A burner and the shape B burner are common in that the oxygen supply pipe, the city gas supply pipe, and the pulverized coal supply pipe are annularly provided in this order from the outside to the center, but the shape A burner is While eight pipes having a diameter of 2 mm for supplying city gas are provided, the burner of the shape B is provided with 16 pipes having a diameter of 3 mm for supplying city gas. The cross-sectional area of the outlet for city gas in the burner of shape A is 1/4.5 of the cross-sectional area of the outlet of shape B. Therefore, even if the city gas flow rate is the same, the city gas flow rate of the burner of shape A is 4.5 times faster than the city gas flow rate of the burner of shape B.
発明例１〜発明例３では、形状Ａのバーナーを用い、表１に示した条件で燃焼試験を実施した。羽口内で逆火が発生すると破裂音が発生する。このため、当該破裂音の発生の有無によって羽口内の逆火発生の有無が判断できるところ、発明例１〜発明例３では、羽口吹き出し部のガス吹出し速度の計算値が１０５ｍ／ｓ以下の燃焼条件であっても破裂音は発生せず、羽口内で逆火は発生しなかった。 In each of Inventive Example 1 to Inventive Example 3, a burner having a shape A was used and a combustion test was performed under the conditions shown in Table 1. A popping sound is generated when a flashback occurs in the tuyere. Therefore, the presence or absence of flashback in the tuyere can be determined based on the presence or absence of the plosive sound. In Invention Example 1 to Invention Example 3, the calculated value of the gas blowing speed of the tuyere blowing portion is 105 m/s or less. No popping sound was produced even under combustion conditions, and flashback did not occur in the tuyere.
図３は、発明例１〜発明例３の羽口内温度および炉体内温度の時間変化を示すグラフである。図３において、横軸は時間（分）であり、縦軸は羽口内および炉体内の温度（℃）である。微粉炭および都市ガスの吹込みによって、炉体内の温度は１５００℃付近まで上昇した。また、羽口内の温度は、常温の酸素の吹込みによって冷却されるので３０℃以下であった。このように、発明例１〜発明例３では逆火が発生せず羽口内の温度が閾値である３００℃以上になっていないので、制御部は、羽口内で逆火が発生したことを検知しなかった。 FIG. 3 is a graph showing changes over time in the tuyere temperature and the furnace body temperature of Invention Example 1 to Invention Example 3. In FIG. 3, the horizontal axis represents time (minutes), and the vertical axis represents temperatures in the tuyere and the furnace body (° C.). By blowing pulverized coal and city gas, the temperature inside the furnace rose to around 1500°C. The temperature in the tuyere was 30° C. or lower because it was cooled by blowing oxygen at room temperature. As described above, in Inventive Examples 1 to 3, since the flashback does not occur and the temperature in the tuyere is not higher than the threshold value of 300° C., the control unit detects that the flashback has occurred in the tuyere. I didn't.
発明例４では、形状Ｂのバーナーを用い、表１に示した条件で燃焼試験を実施した。発明例４では破裂音が発生し、羽口内で逆火が発生した。図４は、発明例４の羽口内温度および炉体内温度の時間変化を示すグラフである。図４において、横軸は時間（分）であり、縦軸は羽口内および炉体内の温度（℃）である。微粉炭および都市ガスの吹込みによって、炉体内の温度は１５００℃付近まで上昇した。また、羽口内の温度は、常温の酸素の吹込みによって冷却され３０℃以下であるものの、羽口内で逆火が発生すると羽口内の温度は閾値の３００℃を超える５００℃以上に上昇した。羽口内の温度が閾値の３００℃を超える５００℃以上に上昇したので、制御部は羽口内で逆火が発生したことを検知した。 In Inventive Example 4, a burner having a shape B was used and a combustion test was performed under the conditions shown in Table 1. In Invention Example 4, a plosive sound was generated and a flashback occurred in the tuyere. FIG. 4 is a graph showing the changes over time in the tuyere temperature and furnace temperature of Invention Example 4. In FIG. 4, the horizontal axis represents time (minutes), and the vertical axis represents temperatures in the tuyere and the furnace body (° C.). By blowing pulverized coal and city gas, the temperature inside the furnace rose to around 1500°C. Although the temperature in the tuyere was 30° C. or lower when cooled by blowing oxygen at room temperature, when a flashback occurred in the tuyere, the temperature in the tuyere rose to 500° C. or higher, which exceeded the threshold of 300° C. Since the temperature in the tuyere rose above the threshold of 300° C. to 500° C. or higher, the control unit detected that a flashback had occurred in the tuyere.
比較例１では、形状Ｂのバーナーを用い、表１に示した条件で燃焼試験を実施した。但し、比較例１の羽口設備には、羽口内の温度を測定する熱電対が設けられていない。 In Comparative Example 1, a burner having a shape B was used and a combustion test was performed under the conditions shown in Table 1. However, the tuyere equipment of Comparative Example 1 is not provided with a thermocouple for measuring the temperature inside the tuyere.
比較例１においても破裂音が発生し、羽口内で逆火が発生した。しかしながら、比較例１の羽口設備には熱電対が設けられていないので、羽口内の温度を測定できず、このため、羽口内で逆火が発生したことを検知できなかった。 In Comparative Example 1 also, a popping sound was generated and a flashback was generated in the tuyere. However, since the thermocouple was not provided in the tuyere equipment of Comparative Example 1, the temperature in the tuyere could not be measured, and therefore, it was not possible to detect that the flashback occurred in the tuyere.
このように、逆火が発生していない羽口内の温度は３０℃以下であって、閾値である３００℃を超えることがない。一方、羽口内で逆火が発生すると羽口内の温度は、閾値である３００℃を超える５００℃以上に上昇する。このため、２秒ごとに熱電対を用いて羽口内の温度を測定し、羽口内の温度が予め定められた閾値以上に上昇した場合に、羽口内で逆火が発生したことを検知することで、酸素高炉における羽口内の逆火の発生を早期に検知できることがわかる。そして、羽口内の逆火の発生を検知した場合に、バーナーへの気体燃料および個体燃料の供給を停止させることで、羽口内の逆火を早期に鎮火でき、これにより、酸素高炉の操業で逆火が発生したとしても羽口設備１０への影響を少なくできる。 As described above, the temperature in the tuyere where the flashback does not occur is 30° C. or less and does not exceed the threshold value of 300° C. On the other hand, when a flashback occurs in the tuyere, the temperature in the tuyere rises above 500° C., which exceeds the threshold of 300° C. For this reason, the temperature inside the tuyere should be measured every two seconds using a thermocouple, and when the temperature inside the tuyere rises above a predetermined threshold, it is possible to detect that a flashback has occurred within the tuyere. Thus, it can be seen that the occurrence of flashback in the tuyeres of the oxygen blast furnace can be detected early. Then, when the occurrence of flashback in the tuyere is detected, by stopping the supply of gaseous fuel and solid fuel to the burner, the flashback in the tuyere can be quickly extinguished, which allows the operation of the oxygen blast furnace. Even if a flashback occurs, the influence on the tuyere equipment 10 can be reduced.
同様に、高炉の羽口部を模したオフライン試験設備を用いて本実施形態に係る逆火の検知方法の検証実験を行った。実施例２の試験条件と試験結果を表２に示す。実施例２で用いたオフライン試験設備は、図２に示した羽口設備４０と同じ設備が、炉口２０００ｍｍの炉体に設けられた設備である。オフライン試験設備において、ＵＶセンサは、図２に示した羽口内の位置に設けた。また、炉体内には熱電対を設けた。ＵＶセンサおよび熱電対を用いて、２秒ごとに羽口内の紫外光の発光強度と、炉体内の温度とを測定した。 Similarly, a verification experiment of the flashback detection method according to the present embodiment was conducted using an off-line test facility imitating the tuyere of a blast furnace. Table 2 shows the test conditions and test results of Example 2. The off-line test equipment used in Example 2 is the same equipment as the tuyere equipment 40 shown in FIG. 2 provided in the furnace body with a furnace mouth of 2000 mm. In the off-line test facility, the UV sensor was provided at the position inside the tuyere shown in FIG. A thermocouple was installed in the furnace body. Using a UV sensor and a thermocouple, the emission intensity of the ultraviolet light in the tuyere and the temperature inside the furnace were measured every 2 seconds.
実施例２で用いた羽口設備では、逆火を検知する紫外光の発光強度の閾値をＵＶセンサからの電気信号の出力値で０．５Ｖとした。なお、実施例２においても、制御部は、仮に逆火を検知しても都市ガスおよび微粉炭のバーナーへの供給を停止しない。 In the tuyere equipment used in Example 2, the threshold value of the emission intensity of the ultraviolet light for detecting the flashback was set to 0.5 V as the output value of the electric signal from the UV sensor. Even in the second embodiment, the control unit does not stop the supply of the city gas and the pulverized coal to the burner even if the flashback is detected.
発明例１１〜発明例１３では、形状Ａのバーナーを用い、表２に示した条件で燃焼試験を実施した。羽口内で逆火が発生すると破裂音が発生する。このため、当該破裂音の発生の有無によって羽口内の逆火発生の有無が判断できるところ、発明例１１〜発明例１３では、羽口吹き出し部のガス吹出し速度の計算値が１０５ｍ／ｓ以下の燃焼条件であっても破裂音は発生せず、羽口内で逆火は発生しなかった。 In Inventive Example 11 to Inventive Example 13, a burner having a shape A was used and a combustion test was performed under the conditions shown in Table 2. A popping sound is generated when a flashback occurs in the tuyere. Therefore, the presence or absence of flashback in the tuyere can be determined by the presence or absence of the plosive sound. In Invention Example 11 to Invention Example 13, the calculated value of the gas blowing speed of the tuyere blowing portion is 105 m/s or less. No popping sound was produced even under combustion conditions, and flashback did not occur in the tuyere.
図５は、発明例１１〜発明例１３のＵＶセンサの出力値および炉体内温度の時間変化を示すグラフである。図５において、横軸は時間（分）であり、縦軸はＵＶセンサの出力値（Ｖ）および炉体内の温度（℃）である。微粉炭および都市ガスの吹込みによって、炉体内の温度は１５００℃付近まで上昇した。また、羽口内は、羽口およびバーナーによって外光が遮断されているので、紫外光の発光強度はＵＶセンサの出力値で０．３Ｖ以下であった。このように、発明例１１〜発明例１３では逆火が発生せずＵＶセンサの出力値が閾値である０．５Ｖ以上になっていないので、制御部は、羽口内で逆火が発生したことを検知しなかった。 FIG. 5 is a graph showing changes over time in the output value of the UV sensor and the temperature inside the furnace of Invention Example 11 to Invention Example 13. In FIG. 5, the horizontal axis represents time (minutes), and the vertical axis represents the output value (V) of the UV sensor and the temperature (° C.) inside the furnace. By blowing pulverized coal and city gas, the temperature inside the furnace rose to around 1500°C. In addition, since the outside of the tuyere was blocked by the tuyere and the burner, the emission intensity of the ultraviolet light was 0.3 V or less as the output value of the UV sensor. As described above, in the invention examples 11 to 13, the flashback does not occur and the output value of the UV sensor does not reach the threshold value of 0.5 V or more. Therefore, the control unit determines that the flashback has occurred in the tuyere. Was not detected.
発明例１４では、形状Ｂのバーナーを用い、表２に示した条件で燃焼試験を実施した。発明例１４では破裂音が発生し、羽口内で逆火が発生した。図６は、発明例１４のＵＶセンサの出力値および炉体内温度の時間変化を示すグラフである。図６において、横軸は時間（分）であり、縦軸はＵＶセンサの出力値（Ｖ）および炉体内の温度（℃）である。微粉炭および都市ガスの吹込みによって、炉体内の温度は１５００℃付近まで上昇した。また、羽口内の紫外光の発光強度は、逆火が発生していない状態ではＵＶセンサの出力値で０．３Ｖ以下であるものの、羽口内で逆火が発生すると羽口内の紫外光の発光強度は、ＵＶセンサの出力値で、閾値の０．５Ｖを超える１．０Ｖ以上に上昇した。ＵＶセンサの出力値が閾値の０．５Ｖを超える１．０Ｖに上昇したので、制御部は、羽口内で逆火が発生したことを検知した。 In Inventive Example 14, a burner having a shape B was used and a combustion test was performed under the conditions shown in Table 2. In Invention Example 14, a plosive sound was generated and a flashback occurred in the tuyere. FIG. 6 is a graph showing changes over time in the output value of the UV sensor and the temperature inside the furnace of Inventive Example 14. In FIG. 6, the horizontal axis represents time (minutes), and the vertical axis represents the output value (V) of the UV sensor and the temperature (° C.) inside the furnace. By blowing pulverized coal and city gas, the temperature inside the furnace rose to around 1500°C. Further, the emission intensity of the ultraviolet light in the tuyere is 0.3 V or less as the output value of the UV sensor in the state where the flashback does not occur, but when the flashback occurs in the tuyere, the emission of the ultraviolet light in the tuyere occurs. The intensity is an output value of the UV sensor and increased to 1.0 V or more, which exceeds the threshold value of 0.5 V. Since the output value of the UV sensor increased to 1.0 V, which exceeds the threshold value of 0.5 V, the control unit detected that a flashback had occurred in the tuyere.
比較例１１では、形状Ｂのバーナーを用い、表１に示した条件で燃焼試験を実施した。但し、比較例１の羽口設備には、羽口内の紫外光の発光強度を測定するＵＶセンサが設けられていない。 In Comparative Example 11, a burner having a shape B was used and a combustion test was performed under the conditions shown in Table 1. However, the tuyere equipment of Comparative Example 1 is not provided with a UV sensor for measuring the emission intensity of ultraviolet light in the tuyere.
比較例１においても破裂音が発生し、羽口内で逆火が発生した。しかしながら、比較例１の羽口設備にはＵＶセンサが設けられていないので、羽口内の紫外光の発光強度を測定できず、このため、羽口内で逆火が発生したことを検知できなかった。 In Comparative Example 1 also, a popping sound was generated and a flashback was generated in the tuyere. However, since the tuyere equipment of Comparative Example 1 was not provided with a UV sensor, the emission intensity of the ultraviolet light in the tuyere could not be measured, and therefore the occurrence of flashback in the tuyere could not be detected. ..
このように、逆火が発生していない羽口内の紫外光の発光強度はＵＶセンサの出力値で０．３Ｖ以下であって、閾値である０．５Ｖを超えることがない。一方、羽口内で逆火が発生すると羽口内の紫外光の発光強度は、ＵＶセンサの出力値で閾値である０．５Ｖを超える１Ｖ以上に上昇する。このため、２秒ごとにＵＶセンサを用いて羽口内の紫外光の発光強度を測定し、羽口内の紫外光の発光強度が予め定められた閾値以上に上昇した場合に、羽口内で逆火が発生したことを検知することで、酸素高炉における羽口内の逆火の発生を早期に検知できることがわかる。そして、羽口内の逆火の発生を検知した場合に、バーナーへの気体燃料および個体燃料の供給を停止させることで、羽口内の逆火を早期に鎮火でき、これにより、酸素高炉の操業で逆火が発生したとしても羽口設備１０への影響を少なくできる。 As described above, the emission intensity of the ultraviolet light in the tuyere in which the flashback does not occur is 0.3 V or less as the output value of the UV sensor and does not exceed the threshold value of 0.5 V. On the other hand, when a flashback occurs in the tuyere, the emission intensity of the ultraviolet light in the tuyere rises to 1 V or more, which exceeds the threshold value of 0.5 V in the output value of the UV sensor. Therefore, the emission intensity of the ultraviolet light in the tuyere is measured every two seconds using a UV sensor, and when the emission intensity of the ultraviolet light in the tuyere rises above a predetermined threshold value, the flashback occurs in the tuyere. It can be seen that the occurrence of flashback in the tuyere of the oxygen blast furnace can be detected early by detecting the occurrence of the. Then, when the occurrence of flashback in the tuyere is detected, by stopping the supply of gaseous fuel and solid fuel to the burner, the flashback in the tuyere can be extinguished quickly, which enables the operation of the oxygen blast furnace. Even if a flashback occurs, the influence on the tuyere equipment 10 can be reduced.
１０ 羽口設備
１２ バーナー
１４ 制御弁
１６ 制御弁
１８ 逆火検知装置
２０ 酸素富化空気
２２ 気体燃料
２４ 固体燃料
３０ 熱電対
３２ 制御装置
３４ 制御部
３６ 格納部
４０ 羽口設備
４２ 逆火検知装置
４４ ＵＶセンサ
10 Tuyere equipment 12 Burner 14 Control valve 16 Control valve 18 Flashback detection device 20 Oxygen-enriched air 22 Gas fuel 24 Solid fuel 30 Thermocouple 32 Control device 34 Control unit 36 Storage unit 40 Tuyere facility 42 Flashback detection device 44 UV sensor
Claims (4)
前記羽口内で発生した逆火によって生じる現象を検出して、前記羽口内で逆火が発生したことを検知し、該検知した場合に、前記気体燃料および固体燃料の供給を停止するとともに、停止した気体燃料を供給するラインから窒素を供給する、酸素高炉の操業方法。 A method for operating an oxygen blast furnace, comprising supplying oxygen or oxygen-enriched air containing 50% by volume or more of oxygen and a gaseous fuel and/or a solid fuel into the blast furnace through tuyere,
Detecting a phenomenon caused by the flashback occurring in the tuyere to detect the occurrence of the flashback in the tuyere , and stopping the supply of the gaseous fuel and the solid fuel when the detection is detected. Oxygen blast furnace operating method, in which nitrogen is supplied from the line for supplying the gaseous fuel.
前記羽口内の温度を測定し、前記羽口内の温度が予め定められた閾値以上に上昇した場合に、前記羽口内で逆火が発生したことを検知する、請求項１に記載の酸素高炉の操業方法。 The phenomenon is an increase in temperature due to the flashback,
The oxygen blast furnace according to claim 1, wherein the temperature in the tuyere is measured, and when the temperature in the tuyere rises above a predetermined threshold value, it is detected that a flashback has occurred in the tuyere . Operating method.
前記羽口内の光の強度を測定し、測定された光の強度が予め定められた閾値以上になった場合に、前記羽口内で逆火が発生したことを検知する、請求項１に記載の酸素高炉の操業方法。 The phenomenon is the emission of light from the flashback,
The intensity of light in the tuyere is measured, and when the intensity of the measured light is equal to or higher than a predetermined threshold value, it is detected that a flashback has occurred in the tuyere. Operating method of oxygen blast furnace.
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