JP6256710B2 - Oxygen blast furnace operation method - Google Patents
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- 229910052760 oxygen Inorganic materials 0.000 title claims description 47
- 239000001301 oxygen Substances 0.000 title claims description 45
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims description 43
- 238000000034 method Methods 0.000 title claims description 17
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 45
- 239000007789 gas Substances 0.000 claims description 32
- 238000002485 combustion reaction Methods 0.000 claims description 20
- 239000003638 chemical reducing agent Substances 0.000 claims description 18
- 239000003245 coal Substances 0.000 description 18
- 239000000571 coke Substances 0.000 description 11
- 238000007664 blowing Methods 0.000 description 10
- 239000007787 solid Substances 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 239000000567 combustion gas Substances 0.000 description 2
- 239000002826 coolant Substances 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 238000011017 operating method Methods 0.000 description 2
- 150000002926 oxygen Chemical class 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
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- 238000000926 separation method Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 1
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- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
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- 238000002309 gasification Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
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- 229910052742 iron Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
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Description
本発明は、酸素高炉の操業方法に関し、特に羽口から純酸素を吹き込んで炉頂から窒素が実質的に含まれていない高炉ガスを発生させるタイプの酸素高炉の操業方法について提案する。 The present invention relates to a method for operating an oxygen blast furnace, and in particular, proposes a method for operating an oxygen blast furnace in which pure oxygen is blown from a tuyere and blast furnace gas containing substantially no nitrogen is generated from the top of the furnace.
近年、製鉄所においては、地球環境問題の観点から省エネ、省資源、炭酸ガス(CO2)発生の抑制などの技術開発が強く求められている。このような背景の下で、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。
従来の一般的な高炉というのは、羽口から熱風を吹き込むタイプのものである。その熱風は、これを作り出す熱源として、高炉やコークス炉、転炉などから発生する副生ガスを混合したガス(Mガス)が使用される。それは、熱風のもつ熱量分だけ、還元材の比率を低減できるからである。即ち、熱風を使用することの意義は、従来の高炉で使用されている還元材が、炭素を主成分とする化石燃料で構成されることから、その熱風送風によって、化石燃料の使用量およびCO2発生量を抑制することができるという点にある。
In recent years, steelworks have been strongly required to develop technologies such as energy saving, resource saving, and suppression of carbon dioxide (CO 2 ) generation from the viewpoint of global environmental problems. Against this background, in recent blast furnace operations, low-reducing material ratio (low RAR) operations are strongly promoted.
A conventional general blast furnace is a type in which hot air is blown from a tuyere. The hot air uses a gas (M gas) mixed with a by-product gas generated from a blast furnace, a coke oven, a converter, or the like as a heat source for generating the hot air. This is because the ratio of the reducing material can be reduced by the amount of heat of the hot air. In other words, the significance of using hot air is that the reducing material used in conventional blast furnaces is composed of fossil fuel containing carbon as a main component. 2 The amount of generation can be suppressed.
ところで、従来、その熱風(熱風炉から供給される高温送風)を用いずに羽口から常温の純酸素を吹き込んで溶銑を製造する酸素高炉が提案されている(特許文献1)。この酸素高炉は、炉頂から窒素を含まない高炉ガスを発生させることができるので、これを合成化学工業用ガスとして使用することができるという利点がある。ただし、この酸素高炉では、羽口から純酸素を吹き込んで炉内滞留コークスと反応させるため、羽口先温度が異常に高温になるという課題があった。従って、このような酸素高炉の操業では、羽口先の燃焼領域の温度(羽口先温度)を適正に制御する必要があり、特許文献1においては、CO2を含む炉頂ガスを還流させて羽口から吹き込むことにより、所定の温度範囲に制御する方法を提案している。また、羽口から常温の純酸素と共に冷却化剤であるH2OまたはCO2を炉内に吹き込んで窒素を含まない高炉ガスを発生させるという方法を提案している。 By the way, the oxygen blast furnace which manufactures hot metal by inject | pouring pure oxygen of normal temperature from a tuyere without using the hot air (high temperature ventilation supplied from a hot air furnace) conventionally is proposed (patent document 1). Since this oxygen blast furnace can generate blast furnace gas containing no nitrogen from the top of the furnace, there is an advantage that it can be used as a gas for the synthetic chemical industry. However, this oxygen blast furnace has a problem that the temperature at the tip of the tuyere becomes abnormally high because pure oxygen is blown from the tuyere and reacted with the coke in the furnace. Therefore, in the operation of such an oxygen blast furnace, it is necessary to appropriately control the temperature of the combustion region of the tuyere (tuyere tip temperature). In Patent Document 1, the top gas containing CO 2 is recirculated to recirculate the vane. A method of controlling to a predetermined temperature range by blowing from the mouth is proposed. Also proposed is a method in which H 2 O or CO 2 as a cooling agent is blown into the furnace together with pure oxygen at room temperature from the tuyere to generate blast furnace gas that does not contain nitrogen.
その他、純酸素と共に、羽口先温度を調整するために重質油を羽口から吹き込む酸素高炉の操業方法についての提案もある(特許文献2)。 In addition, there is a proposal for a method of operating an oxygen blast furnace in which heavy oil is blown from the tuyere to adjust tuyere tip temperature together with pure oxygen (Patent Document 2).
上述した従来技術、例えば特許文献1に開示の酸素高炉の操業方法の場合、羽口から純酸素を吹き込む酸素高炉では、前述したように、羽口先温度が極めて高温になるという課題がある。そのために、従来の酸素高炉については、羽口先の温度を低下させる操業技術が必須となる。この点、高温空気を羽口から吹き込む一般的な熱風高炉では羽口先が異常高温化する問題は起こらない。即ち、羽口先の温度が高温化するのは、酸素高炉に特有の問題であって、例えば、特許文献1では羽口から常温純酸素とともにH2OやCO2を吹き込んだときの吸熱反応を利用して羽口前の温度を低下させており、燃焼(酸化)とは逆反応(還元)の吸熱反応を利用して、異常高温化した羽口先温度を低温化しているのである。 In the case of the oxygen blast furnace operating method disclosed in Patent Document 1, for example, the oxygen blast furnace in which pure oxygen is blown from the tuyere, there is a problem that the tuyere tip temperature becomes extremely high as described above. Therefore, for conventional oxygen blast furnaces, an operation technique that lowers the temperature of the tuyere is essential. In this regard, in a general hot air blast furnace in which high-temperature air is blown from the tuyere, the problem of abnormally high tuyere tips does not occur. That is, the temperature at the tip of the tuyere is a problem peculiar to the oxygen blast furnace. For example, in Patent Document 1, the endothermic reaction when H 2 O or CO 2 is blown together with pure oxygen from the tuyere is performed. The temperature in front of the tuyere is lowered by utilizing the endothermic reaction that is the reverse reaction (reduction) to combustion (oxidation), and the temperature of the tuyere tip that has become abnormally high is lowered.
このように、従来の酸素高炉の場合、純酸素を熱風高炉のように羽口から単に吹き込むと、羽口先の温度が不可避に上昇してしまい、適正な温度に維持(低下)させることは困難であった。 Thus, in the case of the conventional oxygen blast furnace, if pure oxygen is simply blown from the tuyere like a hot air blast furnace, the temperature of the tuyere tip inevitably rises, and it is difficult to maintain (decrease) it at an appropriate temperature. Met.
そこで、羽口から冷却化剤である固体還元剤を吹き込む方法が開発されている。一般に、その固体還元剤は、これを完全に燃焼させてガス化することが好ましいと云えるが、通常の熱風高炉などでは、例えば特開2011−174171号公報に開示されているように、いわゆる支燃性ガスを同時に吹き込む方法などの燃焼改善手段が採られている。しかし、酸素高炉の操業においては、基本的に酸素と可燃物以外に熱による着火が必要であり、純酸素を用いる場合は着火後の燃焼温度は異常高温となる一方で、吹き込み酸素自体は常温であるため着火が遅れ、燃え尽きない固体還元剤が炉内に堆積してガスの通過を阻害するという新たな問題もあった。一方で、従来の熱風高炉では可能であった、酸素濃度の調整や送風温度の調整は該酸素高炉では採用できないという問題もある。 Therefore, a method of blowing a solid reducing agent as a cooling agent from the tuyere has been developed. In general, it can be said that the solid reducing agent is preferably completely gasified by burning it. However, in a normal hot air blast furnace, for example, as disclosed in JP 2011-174171 A, so-called Combustion improvement means such as a method of blowing inflammable gas at the same time is employed. However, in the operation of an oxygen blast furnace, it is basically necessary to ignite with heat in addition to oxygen and combustibles. When pure oxygen is used, the combustion temperature after ignition becomes abnormally high, while the injected oxygen itself is at room temperature. Therefore, there was another problem that ignition was delayed and a solid reducing agent that did not burn out was deposited in the furnace and obstructed the passage of gas. On the other hand, there is also a problem that the oxygen concentration adjustment and the blast temperature adjustment, which are possible with the conventional hot air blast furnace, cannot be adopted with the oxygen blast furnace.
そこで、本発明の目的は、羽口前温度を適正なレベルに維持して安定した酸素高炉の操業を可能とする技術を提案することにある。 Therefore, an object of the present invention is to propose a technique that enables stable operation of an oxygen blast furnace while maintaining the temperature at the front of the tuyere at an appropriate level.
従来技術が抱えている上述した課題の解決を目指し、そして本発明の前記目的の実現に向けて鋭意検討した結果、発明者らは、下記の要旨構成に係る本発明に想到した。即ち、本発明は、還元剤と共に純酸素を羽口を介して炉内に吹き込む酸素高炉の操業に当たり、炉内に吹き込むその純酸素は吹き込み全純酸素量の20vol.%以下が300℃〜600℃の予熱純酸素であり、かつこの予熱純酸素を多重管もしくは複数配管を用いて前記還元剤流の近傍に吹き込むことを特徴とする酸素高炉の操業方法である。 As a result of diligent investigations aimed at solving the above-mentioned problems of the prior art and realizing the object of the present invention, the inventors have arrived at the present invention according to the following summary configuration. That is, according to the present invention, in operation of an oxygen blast furnace in which pure oxygen is blown into the furnace through the tuyere together with the reducing agent, the pure oxygen blown into the furnace is 20 vol. % Or less is preheated pure oxygen at 300 ° C. to 600 ° C. , and this preheated pure oxygen is blown into the vicinity of the reducing agent flow using a multiple pipe or a plurality of pipes .
なお、本発明に係る前記酸素高炉の操業方法において、前記予熱純酸素は、熱交換または可燃性ガスを添加して燃焼させて得られるものを用いることが、より好ましい解決手段になり得るものと考えられる。 In the operation method of the oxygen blast furnace according to the present invention, the preheated pure oxygen may be a more preferable solution by using heat exchange or a product obtained by adding and combusting a combustible gas. Conceivable.
前記のような構成を有する本発明の酸素高炉の操業方法によれば、この高炉が抱える特有の課題である異常高温化する羽口前燃焼領域を低温化させることができると同時に、炉内を適正で安定したレベルに維持することができるようになる。しかも、本発明によれば、高炉の羽口先において燃え尽きない固体還元剤の量をなくすことができる効果もある。 According to the operation method of the oxygen blast furnace of the present invention having the above-described configuration, it is possible to lower the temperature at the front of the tuyere before abnormally high temperature, which is a particular problem of the blast furnace, and at the same time, It becomes possible to maintain an appropriate and stable level. Moreover, according to the present invention, there is an effect that the amount of the solid reducing agent that does not burn out at the tuyere of the blast furnace can be eliminated.
図1は、酸素高炉およびその周辺設備の概略を示す略線図である。この図に示すように、酸素高炉は、従来の一般的な熱風高炉と同じように、炉頂からは鉄鉱石や焼結鉱と共にコークスが装入される。そして、炉下部にある羽口からは熱風に代えて基本的には常温の純酸素が吹き込まれる。その純酸素は、酸素プラントを用いた深冷分離等の分離技術を適用して空気から製造するのが一般的である。このときに必要となる電力については、製鉄所で発生するコークス炉ガス、高炉ガス、あるいはこれらの混合ガスを用いて発電したものが使われる。 FIG. 1 is a schematic diagram showing an outline of an oxygen blast furnace and its peripheral equipment. As shown in this figure, in the oxygen blast furnace, coke is charged together with iron ore and sintered ore from the top of the furnace in the same way as a conventional general hot air blast furnace. Then, pure oxygen at room temperature is basically blown from the tuyere at the bottom of the furnace instead of hot air. The pure oxygen is generally produced from air by applying a separation technique such as cryogenic separation using an oxygen plant. As for the electric power required at this time, a coke oven gas generated at an ironworks, a blast furnace gas, or a power generated using a mixed gas thereof is used.
かかる酸素高炉の操業に当たっては、前記羽口から純酸素とともに微粉炭や天然ガス、コークス炉ガスなどの還元剤も吹き込まれる。このときに使用される羽口としては、中心通路部分に微粉炭用バーナーを備えている多重管型の羽口を用い、その中心部にあるバーナー管からは微粉炭と気体還元剤とを吹き込み、環状管からは純酸素を吹き込む形式のものが適用される。このとき、羽口内にバーナー管を1本配置し、そのバーナー管から微粉炭と合成樹脂材を混合して吹き込む方法や、羽口内にバーナー管を2本配置し、一方から微粉炭、他方から気体還元剤を吹き込むようにしてもよい。 In the operation of the oxygen blast furnace, reducing agents such as pulverized coal, natural gas and coke oven gas are blown from the tuyere together with pure oxygen. As a tuyere used at this time, a multi-tube type tuyere equipped with a burner for pulverized coal in the central passage portion is used, and pulverized coal and a gas reducing agent are blown from the burner tube in the center. From the annular tube, a type in which pure oxygen is blown is applied. At this time, one burner tube is arranged in the tuyere, and a method in which pulverized coal and a synthetic resin material are mixed and blown from the burner tube, or two burner tubes are arranged in the tuyere, from one pulverized coal, from the other A gas reducing agent may be blown.
前述したように、酸素高炉ではガス流量が少ないため、炉頂部の温度が低下するという問題が起こる。例えば、炉頂ガス温度が100℃以下になってしまうと、炉頂で結露が発生して操業トラブルを引き起こす。従って、炉頂での炉頂ガス(高炉ガス)温度を100℃以上に保つためには、図1に示すように、COを多く含んだ燃焼ガスである該高炉排ガスの一部を、バーナーにて部分燃焼させ、それを高温のガスにして高炉のシャフト部から炉内に吹き込む方法を採用するとよい。 As described above, since the gas flow rate is small in the oxygen blast furnace, there arises a problem that the temperature at the top of the furnace is lowered. For example, if the furnace top gas temperature becomes 100 ° C. or less, condensation occurs at the furnace top, causing operational troubles. Therefore, in order to maintain the furnace top gas (blast furnace gas) temperature at 100 ° C. or higher at the furnace top, as shown in FIG. 1, a part of the blast furnace exhaust gas, which is a combustion gas containing a large amount of CO, is used as a burner. It is advisable to adopt a method in which partial combustion is performed, and the gas is made into high-temperature gas and blown into the furnace from the shaft portion of the blast furnace.
なお、羽口前温度に関しては、2000℃〜2600℃の範囲内に維持することが好ましい。もし、羽口前の温度が2000℃以下になってしまうと、微粉炭の燃焼が不十分となってしまい、未燃チャーが増大して高炉内の圧損が増大してしまう懸念がある。 In addition, regarding the temperature before tuyere, it is preferable to maintain in the range of 2000 to 2600 degreeC. If the temperature before the tuyere becomes 2000 ° C. or less, there is a concern that the combustion of the pulverized coal becomes insufficient, the unburned char increases and the pressure loss in the blast furnace increases.
一方で、酸素高炉では、羽口から炉内に、熱風(1000℃以上)に代えて基本的には常温の純酸素を高流速(100m/s以上)で吹き込むため、常温酸素自身による羽口の冷却効果が得られる。従って、従来(特開2003−247008号)から指摘されているような、羽口耐火物損傷の懸念は小さく、羽口先温度を2300℃以下に制限する必要もない。一方で、羽口前温度が2600℃以上にまで上がってしまうと、直接還元比率の比率が急増し、炉内の吸熱反応分の増大による操炉困難が予想される。これらの点を鑑みると、羽口前温度は2000℃〜2600℃に調整することが好ましい。 On the other hand, in oxygen blast furnaces, pure oxygen at room temperature is basically blown into the furnace from the tuyere into the furnace at a high flow rate (100 m / s or more) instead of hot air (1000 ° C. or more). The cooling effect can be obtained. Therefore, there is little concern about the tuyere refractory damage as pointed out from the prior art (Japanese Patent Laid-Open No. 2003-247008), and it is not necessary to limit the tuyere tip temperature to 2300 ° C. or lower. On the other hand, if the temperature before the tuyere rises to 2600 ° C. or higher, the ratio of the direct reduction ratio increases rapidly, and it is expected that the furnace operation is difficult due to an increase in the endothermic reaction in the furnace. In view of these points, the pre-tuyere temperature is preferably adjusted to 2000 ° C. to 2600 ° C.
以下、本発明に係る酸素高炉操業方法の一実施形態について、図面を参照してさらに説明する。本発明に係る酸素高炉に用いる羽口1には、図2に示すような、酸素と固体還元剤等とを吹き込むための多重管(図示例は2重管)で構成される純酸素バーナー2が直接接続される。即ち、内管2aの中心通路からは固体還元剤が、その外管2bの環状通路からは酸素が噴射される。そして、燃焼ガスの吹き込み方向の前方のコークス3堆積層には、レースウエイRと呼ばれる燃焼空間が存在し、主としてこの燃焼空間でコークスの燃焼、ガス化が行われる。
Hereinafter, an embodiment of an oxygen blast furnace operating method according to the present invention will be further described with reference to the drawings. The tuyere 1 used in the oxygen blast furnace according to the present invention has a
図3は、前記純酸素のバーナーから純酸素や空気(熱風)と共に微粉炭を吹き込んだときの燃焼状態について、本発明に係る酸素高炉(予熱純酸素含有)、従来の酸素高炉、一般的な熱風高炉の場合について説明する図である。この図に示すように、該バーナー先端からレースウエイR内に吹き込まれた微粉炭は、コークスとともにその揮発分と固定炭素とは燃焼するが、燃焼しきれずに残った、一般にチャーと呼ばれる炭素と灰分の集合体が、未燃チャーとなってレースウエイRから排出される。この場合において、バーナーからの吹き込み速度は、約200m/s程度とすることが好ましいが、長さ1m程度のレースウェイを抜ける前の1/200秒程度までで燃焼を完了させることが望ましい。 FIG. 3 shows an oxygen blast furnace according to the present invention (containing preheated pure oxygen), a conventional oxygen blast furnace, a general combustion state when pulverized coal is blown together with pure oxygen and air (hot air) from the pure oxygen burner. It is a figure explaining the case of a hot air blast furnace. As shown in this figure, the pulverized coal blown into the raceway R from the tip of the burner burns coke and its volatile matter and fixed carbon, but remains unburned and generally called char. The aggregate of ash is discharged from the raceway R as unburned char. In this case, the blowing speed from the burner is preferably about 200 m / s, but it is desirable to complete the combustion within about 1/200 second before exiting the raceway having a length of about 1 m.
この点、酸素高炉ではない従来型の熱風高炉では、吹き込みランスの上流から1000〜1200℃程度の熱風送風があるため、燃焼点からの輻射以外に熱風の滞留伝熱が固体還元剤(ここでは微粉炭)を予熱し、比較的早いタイミングで着火が行われる。しかし、従来型の酸素高炉は、熱風送風がなく、予熱もないため着火が遅れる一方で、窒素を加熱する必要がないため最高温度は高くなる。ただし、最高温度は高いものの着火が遅くなるため、レースウェイR内で燃え尽きない微粉炭は却って増えてしまう。 In this respect, in a conventional hot air blast furnace that is not an oxygen blast furnace, there is a hot air blowing of about 1000 to 1200 ° C. from the upstream of the blowing lance, so that the staying heat transfer of hot air in addition to the radiation from the combustion point is a solid reducing agent (here The pulverized coal is preheated and ignited at a relatively early timing. However, in the conventional oxygen blast furnace, there is no hot air blowing and no preheating, so that ignition is delayed. On the other hand, there is no need to heat nitrogen, so the maximum temperature becomes high. However, although the maximum temperature is high, the ignition slows down, so the number of pulverized coal that does not burn out in the raceway R increases.
そこで、もし、本発明のように、前記バーナーから還元剤と共に予熱した純酸素を吹き込むようにすれば、最高温度を維持したまま、着火を従来型熱風高炉並みに早くすることができるようになる。 Therefore, if pure oxygen preheated together with the reducing agent is blown from the burner as in the present invention, the ignition can be made as fast as the conventional hot air blast furnace while maintaining the maximum temperature. .
例えば、微粉炭吹き込みの場合、着火温度は一般に400℃程度とされているため、純酸素の予熱温度としては、300℃程度から効果が発現する。一方で、予熱酸素は高温になるほど反応性は高く好ましい。しかし、設備保全の観点から、600℃未満とすることが好ましいと言える。 For example, in the case of pulverized coal injection, since the ignition temperature is generally about 400 ° C., the effect is exhibited from about 300 ° C. as the preheating temperature of pure oxygen. On the other hand, the higher the temperature of preheated oxygen, the better the reactivity. However, it can be said that the temperature is preferably less than 600 ° C. from the viewpoint of equipment maintenance.
本発明において、純酸素の吹き込みは、共に吹き込む還元剤でもある微粉炭の流れを助成するというよりもむしろ着火を早くさせることがより重要な目的になる。このことから、前記予熱純酸素は微粉炭流れの近傍かつその外周を取り囲むある程度の量が好適である。即ち、その量は吹き込みは全純酸素量のうちの20vol%程度が予熱純酸素とする方が、全吹き込み純酸素を加熱するより経済的で反応効率の上からも好ましい。 In the present invention, the injection of pure oxygen has a more important purpose of accelerating ignition rather than assisting the flow of pulverized coal which is also a reducing agent to be injected together. From this, the preheated pure oxygen is preferably in a certain amount in the vicinity of the pulverized coal flow and surrounding the outer periphery thereof. That is, the amount of blowing is preferably about 20 vol% of the total pure oxygen amount preheated pure oxygen, which is more economical and more efficient in terms of reaction efficiency than heating all the blown pure oxygen.
前述した本発明方法につき、この方法の効果を確認するため、図4に示す燃焼実験装置を用いて燃焼実験を行った。使用した実験炉内には、コークス3が充填されており、レースウェイRで消費されるコークス3は、ホッパ4ら補充した。実際の酸素高炉では、図2に示したように、バーナー2は羽口1に直接、接しているが、本実験装置ではバーナー2の先端から吹き込まれた固体還元剤(ここでは微粉炭)5の燃焼を観察するために、そのバーナー2は羽口1から離れた位置に設置した。そして、実験炉内で発生した排ガスは、サイクロン6と呼ばれる分離装置で排ガスとダストに分離し、そのうちの排ガスは助燃炉などの排ガス処理設備に送給し、一方のダストは捕集箱7に捕集した。
In order to confirm the effect of the method of the present invention described above, a combustion experiment was conducted using the combustion experiment apparatus shown in FIG. The experimental furnace used was filled with
この実験において、純酸素を電気ヒーター8により100〜300℃に予熱し、得られた予熱純酸素を常温の純酸素と合流させて燃焼させたときの微粉炭の温度を2色温度計で測定した。その結果を図5に示すが、予熱純酸素の予熱温度が300℃になると、着火が格段に早くなっていることが確認された。
In this experiment, pure oxygen was preheated to 100 to 300 ° C. with the
なお、純酸素吹込み用バーナーを3重管構造とし、中心通路に微粉炭、その外周の環状通路から、全純酸素量のうちの20vol.%の予熱純酸素に可燃性ガス(ここではプロパン)を添加して300℃に予熱したガスを流し、そして最も外側の外環状通路からは80vol.%の量の常温純酸素を吹き込んだところ、この場合において、大幅な着火促進効果が観測された。
なお、この実施例では、3重管構造により300℃にしたガスを微粉炭に合流させたが、別な配管から同様の純酸素を微粉炭流に合流(吹き込ん)させもよい。
The pure oxygen blowing burner has a triple pipe structure, pulverized coal in the central passage, and 20 vol. % Of preheated pure oxygen to which combustible gas (propane in this case) is added and gas preheated to 300 ° C. is allowed to flow, and 80 vol. % Of room temperature pure oxygen was injected, and in this case, a significant ignition promotion effect was observed.
In this embodiment, the gas heated to 300 ° C. by the triple pipe structure is merged with the pulverized coal, but similar pure oxygen may be merged (injected) into the pulverized coal flow from another pipe.
本発明において提案する技術は、酸素高炉の操業だけでなく、酸素富化型熱風高炉への適用もまた可能である。 The technique proposed in the present invention can be applied not only to the operation of an oxygen blast furnace but also to an oxygen-enriched hot air blast furnace.
1 羽口
2 バーナー
2a 内管
2b 外管
3 コークス
4 固体還元剤
6 サイクロン
7 捕集箱
8 電気ヒータ
1
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