JP6518954B2 - Blast furnace operation method - Google Patents
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本発明は、易燃性還元材を吸着させた固体還元材を高炉羽口から吹込み、還元材比を低減させる高炉操業方法に関する。 The present invention relates to a blast furnace operation method in which a solid reducing material to which a flammable reducing material is adsorbed is blown from a blast furnace tuyere to reduce a reducing material ratio.
近年、炭酸ガス排出量の増加による地球温暖化が問題となっており、製鉄業においても排出ＣＯ２の抑制は重要な課題である。これを受け、最近の高炉操業では、低還元材比（低ＲＡＲ：Ｒｅｄｕｃｔｉｏｎ Ａｇｅｎｔ Ｒａｔｉｏの略で、銑鉄１ｔ製造当りの、羽口からの吹込み還元材と炉頂から装入されるコークスの合計量）操業が強力に推進されている。高炉は、主にコークスおよび羽口から吹込む微粉炭を還元材として使用しており、低還元材比、ひいては炭酸ガス排出抑制を達成するためには微粉炭の燃焼性を改善し、コークスの使用量を低減する方策が有効である。 In recent years, global warming due to an increase in carbon dioxide gas emissions has become a problem, and also in the iron and steel industry, the control of emission CO 2 is an important issue. In response to this, in recent blast furnace operations, it is an abbreviation for Low RAR (Reduction Agent Ratio), and it is the sum of the blowout reducing material from the tuyere and the coke charged from the furnace top per 1t of pig iron. Amount) Operation is strongly promoted. The blast furnace mainly uses coke and pulverized coal blown from the tuyere as a reducing agent, and improves the combustibility of pulverized coal to achieve a low reducing material ratio and, consequently, carbon dioxide emission control, Measures to reduce the amount used are effective.
特許文献１には、５０〜１５０℃の温度範囲のＯ２含有雰囲気に吹込み炭を曝し、Ｏ２を吹込み炭に化学吸着させて未燃炭素量を減少させる技術が開示されている。また、特許文献２には、羽口から還元材を吹込むランスを２重管とし、２重管ランスの内管から都市ガスまたは微粉炭を吹き込み、２重管ランスの外管から微粉炭または都市ガスを吹き込んで微粉炭の燃焼性を改善させる技術が開示されている。 Patent Document 1 discloses a technique for exposing blow coal to an O 2 -containing atmosphere in a temperature range of 50 to 150 ° C., and causing O 2 to be chemically adsorbed to the blow coal to reduce the amount of unburned carbon. Further, in Patent Document 2, a lance for blowing a reducing material from a tuyere is a double pipe, a city gas or pulverized coal is blown from an inner pipe of the double pipe lance, and pulverized coal or an outer pipe of the double pipe lance is used. There is disclosed a technology for blowing in city gas to improve the combustibility of pulverized coal.
特許文献１に開示された発明炭はＯ原子含有割合が高く、かつＯ２が化学吸着しているので、燃焼温度が高くなることが記載されている。しかし、従来炭と比較してＯ含有割合が高いことからＣの含有割合が低く、燃焼により発生するＣＯガス発生量も低下する。高炉において鉄鉱石から溶銑への還元はＣＯガスによるガス還元が主である。吹込み炭からのＣＯガス発生量が低下した場合、それを補うために必要なコークス原単位を増加させることが必要になり、結果的に還元材原単位が増加する可能性がある。 It is described that the invention coal disclosed in Patent Document 1 has a high O atom content ratio and O 2 is chemisorbed, so the combustion temperature becomes high. However, since the O content ratio is higher than that of conventional coal, the C content ratio is low, and the amount of CO gas generated by combustion also decreases. The reduction from iron ore to hot metal in blast furnaces is mainly gas reduction with CO gas. If the amount of CO gas generation from the blown coal decreases, it is necessary to increase the amount of coke per unit necessary to make up for it, and as a result, the unit per unit of reducing material may be increased.
また、特許文献２に開示された高炉操業方法は、微粉炭だけを羽口から吹込む方法に比べれば微粉炭の燃焼温度の向上や還元材原単位の低減に効果がある。しかしながら、内管または外管から独立して都市ガスと微粉炭とを吹込んでいるので、微粉炭はランスから粒子群として吐出される。このため、例えば、内管から微粉炭、外管から都市ガスを吹込んだ場合に、粒子群の外側に存在する微粉炭には都市ガスの燃焼由来の燃焼熱を伝えて燃焼性を改善できるものの、粒子群の内側に存在する微粉炭には都市ガスの燃焼由来の燃焼熱を伝えることができず燃焼性を改善できない。このように、特許文献２に記載された高炉操業方法は、部分的な微粉炭の燃焼性の改善はなされるものの、微粉炭全体の燃焼性を改善できない、という課題があった。 In addition, the blast furnace operation method disclosed in Patent Document 2 is effective in the improvement of the combustion temperature of the pulverized coal and the reduction of the reducing material consumption rate, as compared with the method of blowing only pulverized coal from the tuyere. However, since the city gas and the pulverized coal are blown independently of the inner pipe or the outer pipe, the pulverized coal is discharged from the lance as a particle group. For this reason, for example, when pulverized coal from the inner pipe and city gas from the outer pipe are blown, the combustion heat derived from the combustion of the city gas can be transmitted to the pulverized coal present outside the particle group to improve the combustibility However, the heat of combustion derived from the combustion of the city gas can not be transmitted to the pulverized coal present inside the particle group, and the combustibility can not be improved. Thus, the blast furnace operation method described in Patent Document 2 has a problem that although the combustibility of the pulverized coal is partially improved, the combustibility of the whole pulverized coal can not be improved.
本発明は、上記課題を鑑みてなされたものであり、その目的は、所定量の易燃性還元材を固体還元材に吸着させ、２重管のランスの内管および外管の一方から当該固体還元材を高炉内へ吹込み、固体還元材を吹込んでいない２重管ランスの内管または外管から酸素を高炉内へ吹込むことで固体還元材全体の燃焼性を改善させ、これにより、高炉の還元材比を低減させることにある。 The present invention has been made in view of the above problems, and an object thereof is to make a solid reducing material adsorb a predetermined amount of a flammable reducing material, and from one of an inner pipe and an outer pipe of a lance of a double pipe. The solid reducing material is blown into the blast furnace, and oxygen is blown into the blast furnace from the inner pipe or the outer pipe of the double pipe lance without blowing the solid reducing material, thereby improving the combustibility of the entire solid reducing material, thereby And reducing the reducing material ratio of the blast furnace.
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）高炉羽口から固体還元材を吹込む高炉操業方法であって、２重管ランスの内管および外管の一方から、易燃性還元材を０．３ｋｇ／ｔ−銑鉄以上吸着させた固体還元材を前記高炉羽口から高炉内へ吹込み、前記固体還元材を吹込んでいない前記２重管ランスの内管または外管から酸素を前記高炉羽口から前記高炉内へ吹込むことを特徴とする高炉操業方法。
（２）高炉羽口から固体還元材を吹込む高炉操業方法であって、２重管ランスの内管および外管の一方から、比表面積が２．０ｍ２／ｇ以上である固体還元材を前記高炉羽口から高炉内へ吹込み、前記固体還元材を吹込んでいない前記２重管ランスの内管または外管から酸素を前記高炉羽口から前記高炉内へ吹込むことを特徴とする高炉操業方法。
（３）高炉羽口から固体還元材を吹込む高炉操業方法であって、２重管ランスの内管および外管の一方から、比表面積が２．０ｍ２／ｇ以上であり、易燃性還元材を０．３ｋｇ／ｔ−銑鉄以上吸着させた固体還元材を前記高炉羽口から高炉内へ吹込み、前記固体還元材を吹込んでいない前記２重管ランスの内管または外管から酸素を前記高炉羽口から前記高炉内へ吹込むことを特徴とする高炉操業方法。
（４）高炉羽口から固体還元材を吹込む高炉操業方法であって、２重管ランスの内管および外管の一方から、易燃性還元材の吸着量が０．３ｋｇ／ｔ−銑鉄未満の固体還元材に、易燃性還元材の吸着量が０．３ｋｇ／ｔ−銑鉄以上の固体還元材を、全固体還元材量に対して１５質量％以上となるように配合して前記高炉羽口から高炉内へ吹込み、前記固体還元材を吹込んでいない前記２重管ランスの内管または外管から酸素を前記高炉羽口から前記高炉内へ吹込むことを特徴とする高炉操業方法。
（５）高炉羽口から固体還元材を吹込む高炉操業方法であって、２重管ランスの内管および外管の一方から、易燃性還元材の吸着量が０．３ｋｇ／ｔ−銑鉄未満の固体還元材に、比表面積が２．０ｍ２／ｇ以上であり、易燃性還元材を０．３／ｔ−銑鉄以上吸着させた固体還元材を、全固体還元材量に対して１０質量％以上となるように配合して前記高炉羽口から高炉内へ吹込み、前記固体還元材を吹込んでいない前記２重管ランスの内管または外管から酸素を前記高炉羽口から前記高炉内へ吹込むことを特徴とする高炉操業方法。
（６）前記固体還元材は、微粉炭であることを特徴とする（１）から（５）の何れか１つに記載の高炉操業方法。
（７）前記微粉炭に、廃プラスチック、廃棄物固形燃料、有機性資源、および、廃材の少なくとも１つを混合することを特徴とする（６）に記載の高炉操業方法。
The features of the present invention for solving such problems are as follows.
(1) A blast furnace operation method in which a solid reducing material is blown from a blast furnace tuyere, wherein at least 0.3 kg / t-iron of a flammable reducing material is adsorbed from one of the inner pipe and the outer pipe of a double pipe lance. Blowing the solid reducing material into the blast furnace from the blast furnace tuyere, and blowing oxygen from the blast furnace tuyere into the blast furnace from the inner pipe or the outer pipe of the double pipe lance without blowing the solid reducing material. Blast furnace operation method characterized by
(2) A method for operating a blast furnace in which a solid reducing material is blown from a blast furnace tuyere, wherein the solid reducing material having a specific surface area of 2.0 m 2 / g or more from one of an inner pipe and an outer pipe of a double pipe lance. A blast furnace characterized by blowing oxygen into the blast furnace from the blast furnace tuyere and blowing oxygen from the blast furnace tuyere from the inner pipe or the outer pipe of the double pipe lance not injected with the solid reducing material. How to operate
(3) A blast furnace operation method wherein a solid reducing material is blown from a blast furnace tuyere, wherein the specific surface area is 2.0 m 2 / g or more from one of the inner pipe and the outer pipe of the double pipe lance, and is flammable Solid reducing material adsorbed with reducing material of 0.3 kg / t-pig iron or more is blown into the blast furnace from the blast furnace tuyere, and oxygen is fed from the inner pipe or the outer pipe of the double pipe lance without blowing the solid reducing material. A blast furnace operation method comprising: blowing the air from the blast furnace tuyere into the blast furnace.
(4) A blast furnace operation method wherein a solid reducing material is blown from a blast furnace tuyere, wherein the adsorption amount of the flammable reducing material is 0.3 kg / t-pig iron from one of the inner pipe and the outer pipe of the double pipe lance. The solid reducing material having an adsorption amount of 0.3 kg / t-iron or more is mixed with the solid reducing material having a concentration of less than 0.3 kg / t-iron so as to be 15% by mass or more based on the total solid reducing material A blast furnace operation characterized in that oxygen is blown into the blast furnace from the blast furnace tuyere by blowing into the blast furnace from the blast furnace tuyere and from the inner pipe or the outer pipe of the double pipe lance not blown with the solid reducing material. Method.
(5) A blast furnace operation method wherein a solid reducing material is blown from a blast furnace tuyere, wherein the adsorption amount of the flammable reducing material is 0.3 kg / t-pig iron from one of the inner pipe and the outer pipe of the double pipe lance. The solid reducing material having a specific surface area of 2.0 m 2 / g or more and having a flammable reducing material adsorbed by 0.3 / t-iron or more with respect to the total solid reducing material It mixes so that it will be 10 mass% or more, blows into the blast furnace from the blast furnace tuyere, and does not blow the solid reducing material from the blast furnace tuyere with oxygen from the inner pipe or the outer pipe of the double pipe lance. A blast furnace operation method characterized by blowing into the blast furnace.
(6) The method for operating a blast furnace according to any one of (1) to (5), wherein the solid reducing material is pulverized coal.
(7) The blast furnace operation method according to (6), wherein the pulverized coal is mixed with at least one of waste plastic, solid waste fuel, organic resources, and waste material.
本発明の高炉操業方法を実施することで、高炉羽口から吹込む固体還元材の全体の燃焼性を改善させることができる。全体の燃焼性が改善された固体還元材は、部分的に燃焼性が改善された固体還元材と比較して、より少ない固体還元材量で高炉の炉内温度を高めることができるので、本発明の高炉操業方法を実施することで高炉の還元材比の低減が実現できる。 By carrying out the blast furnace operation method of the present invention, the overall combustibility of the solid reducing material blown from the blast furnace tuyere can be improved. Since the solid reducing material with improved overall flammability can raise the temperature in the blast furnace furnace with a smaller amount of solid reducing material as compared with the solid reducing material with partially improved combustibility, By implementing the blast furnace operation method of the invention, reduction of the reducing material ratio of the blast furnace can be realized.
本発明は、高炉の羽口から固体還元材を吹き込んで高炉の炉内温度をより高める手法として、固体還元材の着火性および燃焼温度に着目した。すなわち、固体還元材に易燃性還元材を０．３ｋｇ／ｔ−銑鉄以上吸着させ、２重管ランスの内管および外管の一方から当該固体還元材を吹込み、固体還元材を吹き込んでいない２重管ランスの内管または外管から酸素を吹込むことで、固体還元材全体の燃焼性を改善させることができる。このように、易燃性還元材を０．３ｋｇ／ｔ−銑鉄以上吸着させた固体還元材と酸素とを２重管ランスを用いて高炉羽口から吹込むことで、高炉の炉内温度をより高めることができ、これにより、高炉の還元材比を低減できることを見出して本発明を完成させた。 The present invention focused on the ignitability and the combustion temperature of the solid reducing material as a method of raising the temperature in the blast furnace by blowing the solid reducing material from the tuyere of the blast furnace. That is, 0.3 kg / t or more of flammable reducing material is adsorbed to the solid reducing material, and the solid reducing material is blown from one of the inner pipe and the outer pipe of the double pipe lance, and the solid reducing material is blown By blowing oxygen from the inner pipe or the outer pipe of the double pipe lance, the burnability of the whole solid reducing agent can be improved. Thus, the temperature in the furnace of the blast furnace is obtained by blowing the solid reducing material adsorbed with a flammable reducing material of 0.3 kg / t or more and oxygen and the oxygen from the blast furnace tuyere using a double tube lance. The present invention has been completed by the finding that it can be further enhanced, thereby reducing the reduction material ratio of the blast furnace.
まず、本発明をするに到った微粉炭の燃焼試験について説明する。比表面積、易燃性還元材であるメタンの吸着量を変えた５種の微粉炭を準備し、燃焼試験を実施した。５種の微粉炭のうち、調整微粉炭１〜４は、含有水分６０質量％、ドライベースの揮発分５０質量％の低品位炭を準備し、５００〜１０００℃の範囲内の温度で所定時間加熱処理して、含有水分を１質量％以下とした。なお、ドライベースとは、微粉炭に含まれる含有水分量を除いた質量を意味する。この加熱処理済みの低品位炭を、例えば、粒径７４μｍ以下の微粉の割合が８０質量％以上になるように粉砕して、比表面積を変えた調整微粉炭１〜４の微粉炭を製造した。 First, a combustion test of pulverized coal which has reached to the present invention will be described. Five types of pulverized coal with different specific surface area and adsorption amount of methane which is a flammable reducing material were prepared, and a combustion test was conducted. Among the five types of pulverized coal, adjusted pulverized coal 1 to 4 prepare low-grade coal containing 60% by mass of water content and 50% by mass of dry base volatile component, and for a predetermined time at a temperature within the range of 500 to 1000 ° C. The heat treatment was performed to make the contained water 1% by mass or less. In addition, dry base means the mass except the moisture content contained in pulverized coal. This heat-treated low-grade coal was pulverized, for example, so that the proportion of fine powder with a particle size of 74 μm or less was 80 mass% or more, to produce pulverized coal of adjusted pulverized coal 1 to 4 having different specific surface areas. .
比表面積は、Ｎ２ガス吸着によるＢＥＴ法で測定した。ＢＥＴ法は、粉末試料に吸着する気体量を吸着気体の圧力の関数として測定する方法である。粉末試料に気体を物理吸着させたとき、吸着した気体量Ｖａと吸着平衡にある吸着気体の圧力Ｐとの間には、Ｐ／Ｐ０の値が０．０５〜０．３０の範囲内で（１）式の関係がある。 The specific surface area was measured by the BET method by N 2 gas adsorption. The BET method is a method of measuring the amount of gas adsorbed to a powder sample as a function of the pressure of the adsorbed gas. When the gas is physically adsorbed to the powder sample, the value of P / P 0 is in the range of 0.05 to 0.30 between the amount of adsorbed gas Va and the pressure P of the adsorbed gas in adsorption equilibrium. (1) There is a relationship of expression.
但し、（１）式において、Ｐは吸着平衡圧（ｋＰａ）であり、Ｐ０は、測定温度における吸着気体の蒸気圧（ｋＰａ）であり、Ｖａは吸着平衡時の吸着量（ｍＬ）であり、Ｖｍは単分子層吸着量（ｍＬ）であり、Ｃは吸着熱、凝縮熱などの定数である。
Where P is the adsorption equilibrium pressure (kPa), P 0 is the vapor pressure of the adsorption gas at the measurement temperature (kPa), and Va is the adsorption amount (mL) at the adsorption equilibrium. , V m is a monolayer adsorption amount (mL), C is a constant such as heat of adsorption, heat of condensation, and the like.
吸着平衡時の吸着量Ｖａは、流動法または容量法を用いて測定できる。流動法は、吸着気体と吸着気体を搬送するキャリア気体の混合気体を試料に接触通過させ、通過前後の吸着気体の濃度変化から吸着量を算出する方法である。容量法は、容積が既知の容器に粉末試料を入れ、試料表面における気体の吸着に伴う圧力変化から吸着量を算出する方法である。粉末試料の比表面積は、（１）式の単分子層吸着量Ｖｍと（２）式とを用いて算出できる。 The adsorption amount Va at the time of adsorption equilibrium can be measured using a flow method or a volumetric method. The flow method is a method in which a mixture gas of an adsorption gas and a carrier gas for transporting the adsorption gas is brought into contact with a sample, and the adsorption amount is calculated from the concentration change of the adsorption gas before and after the passage. The volumetric method is a method in which a powder sample is placed in a container whose volume is known, and the amount of adsorption is calculated from the pressure change associated with the adsorption of gas on the surface of the sample. The specific surface area of the powder sample can be calculated using the monolayer adsorption amount V m of the equation (1) and the equation (2).
但し、（２）式において、Ｓは比表面積（ｍ２／ｇ）であり、Ｎはアボガドロ数であり、ａは吸着気体分子１個の有効断面積（ｍ２）であり、ｍは粉末試料の質量（ｇ）である。
However, in equation (2), S is the specific surface area (m 2 / g), N is the Avogadro's number, a is the effective cross-sectional area of one adsorbed gas molecule (m 2 ), and m is a powder sample Mass (g) of
この微粉炭に１００ｋＰａ以上の圧力でメタンを吸着させた。メタンの吸着量は、メタン吸着前後の微粉炭の質量差から求めた。なお、本燃焼試験におけるメタンは易燃性還元材の一例であり、微粉炭は固体還元材の一例である。 Methane was adsorbed to this pulverized coal at a pressure of 100 kPa or more. The adsorption amount of methane was determined from the mass difference of pulverized coal before and after the adsorption of methane. Methane in the present combustion test is an example of a flammable reducing material, and pulverized coal is an example of a solid reducing material.
微粉炭Ａは、加熱処理せずに、粒径７４μｍ以下の微粉の割合が８０質量％以上になるように粉砕されて製造された微粉炭である。表１に燃焼試験に用いた微粉炭Ａおよび調整微粉炭１〜４のメタン吸着量および比表面積を示す。 Pulverized coal A is pulverized coal which is manufactured without being subjected to heat treatment and pulverized so that the ratio of fine powder having a particle diameter of 74 μm or less is 80% by mass or more. Table 1 shows the methane adsorption amount and specific surface area of pulverized coal A and adjusted pulverized coal 1 to 4 used in the combustion test.
表１に示すように、調整微粉炭１は、メタンの吸着量を０．３ｋｇ／ｔ−銑鉄未満、比表面積を２．０ｍ２／ｇ未満に調整された微粉炭である。調整微粉炭２は、メタンの吸着量を０．３ｋｇ／ｔ−銑鉄以上、比表面積を２．０ｍ２／ｇ未満に調整された微粉炭である。調整微粉炭３は、比表面積を２．０ｍ２／ｇ以上、メタンの吸着量を０．３ｋｇ／ｔ−銑銑未満に調整された微粉炭である。調整微粉炭４は、メタンの吸着量を０．３ｋｇ／ｔ−銑鉄以上、比表面積を２．０ｍ２／ｇ以上に調整された微粉炭である。 As shown in Table 1, the adjusted pulverized coal 1 is a pulverized coal in which the adsorption amount of methane is adjusted to less than 0.3 kg / t-pig iron and the specific surface area to less than 2.0 m 2 / g. The adjusted pulverized coal 2 is a pulverized coal in which the adsorption amount of methane is adjusted to 0.3 kg / t-iron or more and the specific surface area to less than 2.0 m 2 / g. The adjusted pulverized coal 3 is a pulverized coal adjusted to have a specific surface area of 2.0 m 2 / g or more and an adsorption amount of methane of less than 0.3 kg / t- 銑 銑. The adjusted pulverized coal 4 is a pulverized coal in which the adsorption amount of methane is adjusted to 0.3 kg / t-iron or more and the specific surface area to 2.0 m 2 / g or more.
燃焼試験は、高炉の羽口付近を模した装置であって、ランスを介して羽口から吹き込まれた微粉炭が燃焼した位置を視認できるように構成された燃焼実験装置を用いて実施した。羽口からの吹き込み速度を２９．８ｋｇ／ｈ（銑鉄１ｔ当り１００ｋｇに相当）として、２重管ランス内管から微粉炭、外管から流量１２Ｎｍ３／ｈの酸素を吹込んで燃焼試験を実施した。 The combustion test was carried out using a combustion experimental device which simulates the vicinity of the tuyere of a blast furnace and can visually recognize the position where the pulverized coal blown from the tuyere has burned through the lance. Combustion test was carried out by blowing pulverized coal from the inner pipe of double-tube lance and oxygen with a flow rate of 12 Nm 3 / h from the outer pipe, assuming that the blowing speed from the tuyere was 29.8 kg / h (equivalent to 100 kg / t of pig iron) .
微粉炭の送風条件は、送風温度を１２００℃、流量を３００Ｎｍ３／ｈ、流速を７０ｍ／ｓ、Ｏ２富化量を５．５体積％（空気中酸素濃度２１．０体積％に対して酸素濃度２６．５体積％にした）とした。また、微粉炭の搬送ガスにはＮ２を用いた。この試験条件で、微粉炭Ａと、調整微粉炭１〜４の着火性および燃焼温度を評価した。この結果を表２に示す。 The blasting conditions of pulverized coal are as follows: the blasting temperature is 1200 ° C., the flow rate is 300 Nm 3 / h, the flow rate is 70 m / s, the O 2 enrichment amount is 5.5% by volume (with respect to the oxygen concentration in air 21.0% by volume The oxygen concentration was 26.5% by volume). Moreover, N 2 was used for the carrier gas of pulverized coal. Under this test condition, the ignitability and the combustion temperature of the pulverized coal A and the adjusted pulverized coals 1 to 4 were evaluated. The results are shown in Table 2.
また、２重管ランス内管から流量１２Ｎｍ３／ｈの酸素を、外管から微粉炭を吹込んだ場合の燃焼性も同様の燃焼試験で評価した。この結果を表３に示す。 Further, the flammability in the case where oxygen having a flow rate of 12 Nm 3 / h was injected from the double pipe lance inner pipe and the pulverized coal was injected from the outer pipe was also evaluated in the same combustion test. The results are shown in Table 3.
着火性は、着火距離と着火時間で評価した。着火距離とは、ランスから吹き込まれた微粉炭が着火するまでのランス先端からの距離である。この距離が短い微粉炭を着火性に優れる微粉炭と判定し、この距離が長い微粉炭を着火性に劣る微粉炭と判定した。 The ignitability was evaluated by the ignition distance and the ignition time. The ignition distance is the distance from the lance tip until the pulverized coal blown from the lance is ignited. The pulverized coal having a short distance was determined to be pulverized coal having excellent ignitability, and the pulverized coal having a long distance was determined to be pulverized coal having poor ignitability.
図１は、燃焼実験装置１０の部分断面模式図である。図１は、燃焼実験装置１０における２重管ランス１６が設けられた部分を示している。図１に示すように、燃焼実験装置１０の炉壁１２から燃焼実験装置１０の内側に羽口１８が挿入されている。微粉炭は、２重管ランス１６の内管から、搬送ガスであるＮ２とともに送風管（ブローパイプ）１４内に吹き込まれる。また、酸素は、２重管ランス１６の外管から送風管１４内に吹込まれる。送風管１４内に吹き込まれた微粉炭は、酸素とともに羽口１８から燃焼実験装置１０内の高温領域に吹き込まれて着火する。図１において、着火位置２０は、ランス１６から燃焼実験装置１０内に吹き込まれた微粉炭が着火した位置を示す。図１における距離ａは、羽口１８の先端から着火位置２０までの距離であって、表２、表３における着火距離である。距離ａは、ランスから吹込まれる微粉炭流を燃焼実験装置１０に設けられた覗き窓から高速度カメラにより撮影して測定した。 FIG. 1 is a schematic partial cross-sectional view of a combustion experimental device 10. FIG. 1 shows a portion of a combustion experimental device 10 provided with a double pipe lance 16. As shown in FIG. 1, a tuyere 18 is inserted into the combustion experimental device 10 from the furnace wall 12 of the combustion experimental device 10. Pulverized coal, the inner pipe of the double pipe lance 16, is blown into the blast pipe (blow pipe) 14 with N 2 as a transfer gas. In addition, oxygen is blown into the blast pipe 14 from the outer pipe of the double pipe lance 16. The pulverized coal blown into the blast tube 14 is blown into the high temperature region in the combustion experimental device 10 from the tuyere 18 together with oxygen and ignited. In FIG. 1, the ignition position 20 indicates the position at which the pulverized coal blown into the combustion experimental device 10 from the lance 16 is ignited. The distance a in FIG. 1 is the distance from the tip of the tuyere 18 to the ignition position 20 and is the ignition distance in Tables 2 and 3. The distance a was measured by shooting a pulverized coal flow blown from a lance from a observation window provided in the combustion experimental apparatus 10 with a high-speed camera.
同様に、着火時間とは、羽口１８の先端から燃焼実験装置１０内に吹き込まれた微粉炭が、燃焼実験装置１０内で着火するまでの時間である。この時間が短い微粉炭を着火性に優れる微粉炭であると判定し、この時間が長い微粉炭を着火性に劣る微粉炭であると判定した。表２、表３の着火性における「判定」の行に示した「△」は、着火性が微粉炭Ａと同程度であることを意味し、「○」は、着火性が微粉炭Ａよりも優れることを意味し、「◎」は、着火性が微粉炭Ａより大きく優れることを意味する。 Similarly, the ignition time is the time until the pulverized coal blown into the combustion experimental device 10 from the tip of the tuyere 18 is ignited in the combustion experimental device 10. The pulverized coal having a short time was determined to be pulverized coal having excellent ignitability, and the pulverized coal having a long time was determined to be pulverized coal having poor ignitability. “Δ” shown in the “judgement” row in the ignitability in Tables 2 and 3 means that the ignitability is comparable to that of pulverized coal A, “O” means that the ignitability is higher than pulverized coal A “◎” means that the ignitability is significantly superior to pulverized coal A.
また、燃焼温度とは、微粉炭が燃焼した際の温度である。この温度が高い微粉炭を燃焼温度が高い微粉炭であると判定し、この温度が低い微粉炭を燃焼温度が低い微粉炭であると判定した。表２、表３の燃焼温度における「判定」の行に示した「△」は、燃焼温度が１５３０℃未満であることを意味し、「○」は、燃焼温度が１５３０℃以上１５４０℃未満であることを意味し、「◎」は、燃焼温度が１５４０℃以上であることを意味する。なお、微粉炭の燃焼温度は、２色温度計を用いて測定を行なった。 Further, the combustion temperature is a temperature when the pulverized coal burns. The pulverized coal having this high temperature was judged to be pulverized coal having a high combustion temperature, and the pulverized coal having a low temperature was judged to be pulverized coal having a low combustion temperature. The "Δ" shown in the row of "judgment" at the combustion temperature in Table 2 and Table 3 means that the combustion temperature is less than 1530 ° C, and "○" indicates that the combustion temperature is 1530 ° C or more and less than 1540 ° C “◎” means that the combustion temperature is 1540 ° C. or higher. The combustion temperature of pulverized coal was measured using a two-color thermometer.
表２に示すように、微粉炭を２重管の内管から吹込み、酸素を２重管の外管から吹込んだ場合、調整微粉炭１は、微粉炭Ａよりも着火距離が短かったが、その差は僅かであり、また、着火時間が同じであった。このため、調整微粉炭１の着火性は、微粉炭Ａと同程度であると判定した。また、調整微粉炭２および調整微粉炭３は、微粉炭Ａと着火時間が同じであったが、着火距離が微粉炭Ａより短かった。このため、調整微粉炭２および調整微粉炭３の着火性は、微粉炭Ａよりも優れると判定した。調整微粉炭４は、微粉炭Ａよりも着火距離が著しく短くなり、着火時間も著しく早くなった。このため、調整微粉炭４の着火性は、微粉炭Ａよりも大きく優れると判定した。 As shown in Table 2, when pulverized coal was blown from the inner pipe of the double pipe and oxygen was blown from the outer pipe of the double pipe, the adjusted pulverized coal 1 had a shorter ignition distance than that of the pulverized coal A. However, the difference was slight and the ignition time was the same. Therefore, the ignitability of the adjusted pulverized coal 1 was determined to be comparable to that of the pulverized coal A. Moreover, although the adjustment pulverized coal 2 and the adjustment pulverized coal 3 had the same ignition time as the pulverized coal A, the ignition distance was shorter than the pulverized coal A. Therefore, it was determined that the ignitability of the adjusted pulverized coal 2 and the adjusted pulverized coal 3 was superior to the pulverized coal A. The adjusted pulverized coal 4 has a significantly shorter ignition distance than the pulverized coal A, and has a significantly faster ignition time. For this reason, it was determined that the ignitability of the adjusted pulverized coal 4 was larger and superior to the pulverized coal A.
また、燃焼温度について、調整微粉炭１および調整微粉炭２は、微粉炭Ａよりも燃焼温度が高くなったが、その温度が１５３０℃未満であったので「△」と判定した。また、調整微粉炭３の燃焼温度は、微粉炭Ａよりも高くなり、その温度が１５３０℃以上１５４０℃未満の範囲内であったので「○」と判定した。また、調整微粉炭４の燃焼温度は、微粉炭Ａよりも著しく高くなり、その温度が１５４０℃以上であったので「◎」と判定した。 Further, with regard to the combustion temperature, although the combustion temperature of the adjusted pulverized coal 1 and the adjusted pulverized coal 2 was higher than that of the pulverized coal A, the temperature was less than 1530 ° C., so it was determined as “Δ”. Further, the combustion temperature of the adjusted pulverized coal 3 was higher than the pulverized coal A, and the temperature was in the range of 1530 ° C. or more and less than 1540 ° C., so it was determined as “o”. Further, the combustion temperature of the adjusted pulverized coal 4 was significantly higher than that of the pulverized coal A, and the temperature was 1540 ° C. or higher, so it was judged as “◎”.
一方、微粉炭を２重管の外側から吹込み、酸素を２重管の内管から吹込んだ場合、表３に示すように、調整微粉炭１は、微粉炭Ａよりも着火距離が短かったが、その差は僅かであり、また、着火時間が同じであった。このため、調整微粉炭１の着火性は、微粉炭Ａと同程度であると判定した。また、調整微粉炭２および調整微粉炭３は、微粉炭Ａと着火時間が同じであったが、着火距離が微粉炭Ａより短かった。このため、調整微粉炭２および調整微粉炭３の着火性は、微粉炭Ａよりも優れると判定した。調整微粉炭４は、微粉炭Ａよりも着火距離が著しく短くなり、着火時間も著しく早くなった。このため、調整微粉炭４の着火性は、微粉炭Ａよりも大きく優れると判定した。 On the other hand, when pulverized coal is blown from the outside of the double pipe and oxygen is blown from the inner pipe of the double pipe, as shown in Table 3, the adjusted pulverized coal 1 has a shorter ignition distance than pulverized coal A. However, the difference was slight and the ignition time was the same. Therefore, the ignitability of the adjusted pulverized coal 1 was determined to be comparable to that of the pulverized coal A. Moreover, although the adjustment pulverized coal 2 and the adjustment pulverized coal 3 had the same ignition time as the pulverized coal A, the ignition distance was shorter than the pulverized coal A. Therefore, it was determined that the ignitability of the adjusted pulverized coal 2 and the adjusted pulverized coal 3 was superior to the pulverized coal A. The adjusted pulverized coal 4 has a significantly shorter ignition distance than the pulverized coal A, and has a significantly faster ignition time. For this reason, it was determined that the ignitability of the adjusted pulverized coal 4 was larger and superior to the pulverized coal A.
また、燃焼温度について、調整微粉炭１は、微粉炭Ａよりも燃焼温度が高くなったが、その温度が１５３０℃未満であったので「△」と判定した。また、調整微粉炭２および調整微粉炭３の燃焼温度は、微粉炭Ａよりも高くなり、その温度が１５３０℃以上１５４０℃未満の範囲内であったので「○」と判定した。また、調整微粉炭４の燃焼温度は、微粉炭Ａよりも著しく高くなり、その温度が１５４０℃以上であったので「◎」と判定した。表２および表３に示したように、微粉炭を２重管の内管から吹込んだ場合と、２重管の外管から吹込んだ場合とで、着火性および燃焼温度に大きな差は見られなかった。このため、以後の確認においては、２重管ランスの外管から微粉炭を吹込み、２重管ランスの内管から酸素を吹込む確認を省略した。 In addition, regarding the combustion temperature, although the combustion temperature of the adjusted pulverized coal 1 was higher than that of the pulverized coal A, the temperature was less than 1530 ° C., so it was determined as “Δ”. Further, the combustion temperature of the adjusted pulverized coal 2 and the adjusted pulverized coal 3 was higher than the pulverized coal A, and the temperature was in the range of 1530 ° C. or more and less than 1540 ° C., so it was determined as “o”. Further, the combustion temperature of the adjusted pulverized coal 4 was significantly higher than that of the pulverized coal A, and the temperature was 1540 ° C. or higher, so it was judged as “◎”. As shown in Table 2 and Table 3, when the pulverized coal is blown from the inner pipe of the double pipe and when it is blown from the outer pipe of the double pipe, there is a large difference in the ignitability and the combustion temperature I could not see it. For this reason, in subsequent confirmations, the pulverized carbon was blown from the outer pipe of the double pipe lance, and the confirmation that oxygen was blown from the inner pipe of the double pipe lance was omitted.
ここで、表１に示した微粉炭Ａおよび調整微粉炭１〜４のメタン吸着量および比表面積から表２および表３の結果を考察すると、着火性および燃焼温度は、微粉炭へのメタン吸着量と微粉炭の比表面積に影響を受けると考えられる。すなわち、微粉炭粒子に吸着されたメタンは、送風由来の熱により速やかに離脱して微粉炭粒子に近接した位置で燃焼するので、メタンの燃焼によって生じた熱は、微粉炭に効率的に伝熱される。これにより微粉炭全体の着火性が向上し、燃焼温度が高められたと考えられる。また、微粉炭の比表面積が増えると、微粉炭が時間当たりに外部から受ける熱量が増加するとともに微粉炭周囲の酸素との接触性が改善されるので、これにより着火性が向上し、燃焼温度が高められたと考えられる。 Here, considering the results of Tables 2 and 3 from the methane adsorption amount and specific surface area of the pulverized coal A and the adjusted pulverized coal 1 to 4 shown in Table 1, the ignitability and the combustion temperature are the methane adsorption to the pulverized coal. It is believed to be influenced by the amount and specific surface area of pulverized coal. That is, since the methane adsorbed to the pulverized coal particles is quickly desorbed by the heat derived from the blast and burns at a position close to the pulverized coal particles, the heat generated by the combustion of the methane is efficiently transferred to the pulverized coal. Heated. It is thought that the ignitability of the whole pulverized coal was improved by this and the combustion temperature was raised. In addition, when the specific surface area of the pulverized coal increases, the amount of heat externally applied to the pulverized coal per unit time increases and the contact with oxygen around the pulverized coal is improved, thereby improving the ignitability and the combustion temperature Is considered to have been
調整微粉炭１および調整微粉炭２の結果から、メタンを０．３ｋｇ／ｔ−銑鉄以上吸着させた微粉炭を２重管ランスの内管および外管の一方から吹込み、酸素を微粉炭を吹込んでいない２重管ランスの外管または内管から吹込むことで、微粉炭の着火性を向上させ、燃焼温度を高められることが確認された。また、調整微粉炭１および調整微粉炭３の結果から、比表面積を２．０ｍ２／ｇ以上に調整された微粉炭を２重管ランスの内管および外管の一方から吹込み、酸素を微粉炭を吹込んでいない２重管ランスの外管または内管から吹込むことで、微粉炭の着火性を向上させ、燃焼温度を高められることが確認された。更に、調整微粉炭１および調整微粉炭４の結果から、メタンを０．３ｋｇ／ｔ−銑鉄以上吸着させ、比表面積を２．０ｍ２／ｇ以上に調整された微粉炭を２重管ランスの内管および外管の一方から吹込み、酸素を微粉炭を吹込んでいない２重管ランスの外管または内管から吹込むことで、微粉炭の着火性を大きく向上させ、燃焼温度を大きく高められることが確認された。なお、微粉炭の比表面積が大きい程微粉炭の燃焼性が向上するので、微粉炭の比表面積の上限は設けなくてよい。しかしながら、揮発分を多く含み空孔が多い比表面積の大きい石炭であっても、その比表面積は最大で１０ｍ２／ｇ程度である。この石炭の比表面積を更に大きくするには乾留する等の予備処理が必要になり、当該予備処理を行うと石炭に含まれる揮発分が減少して石炭の着火性が低下する。このため、微粉炭の比表面積は、１０００ｍ２／ｇ以下とすることが好ましい。 From the results of adjusted pulverized coal 1 and adjusted pulverized coal 2, pulverized coal on which methane is absorbed by 0.3 kg / t-pig iron or more is injected from one of the inner pipe and the outer pipe of double tube lance, and oxygen is pulverized coal. It has been confirmed that the ignitability of the pulverized coal can be improved and the combustion temperature can be raised by blowing from the outer pipe or the inner pipe of the double pipe lance which is not blown. Also, based on the results of adjusted pulverized coal 1 and adjusted pulverized coal 3, pulverized coal whose specific surface area was adjusted to 2.0 m 2 / g or more was blown in from one of the inner pipe and the outer pipe of the double pipe lance to carry out oxygen. It has been confirmed that the ignitability of the pulverized coal can be improved and the combustion temperature can be increased by blowing the pulverized coal from the outer pipe or the inner pipe of the double pipe lance not injected. Furthermore, from the results of the adjustment pulverized coal 1 and the adjustment pulverized coal 4, the pulverized coal having a specific surface area adjusted to 2.0 m 2 / g or more by adsorbing methane at 0.3 kg / t-pig iron or more and having a double tube lance By blowing oxygen from one of the inner and outer pipes and blowing the oxygen from the outer pipe or the inner pipe of the double pipe lance without blowing the pulverized coal, the ignitability of the pulverized coal is greatly improved and the combustion temperature is greatly increased. It was confirmed that In addition, since the combustibility of pulverized coal improves as the specific surface area of pulverized coal is larger, the upper limit of the specific surface area of pulverized coal may not be provided. However, even a coal having a large volatile content and a large specific surface area with many pores has a specific surface area of about 10 m 2 / g at the maximum. In order to further increase the specific surface area of the coal, pretreatment such as dry distillation is required, and when the pretreatment is performed, the volatile matter contained in the coal is reduced and the ignitability of the coal is reduced. For this reason, it is preferable that the specific surface area of pulverized coal be 1000 m 2 / g or less.
また、同じ条件で、単管ランスから、２９．８ｋｇ／ｈ（銑鉄１ｔ当り１００ｋｇに相当）の調整微粉炭４を吹込んだ場合の着火性および燃焼温度を評価した。この結果を表４に示す。 In addition, under the same conditions, the ignition performance and the combustion temperature were evaluated when 29.8 kg / h (corresponding to 100 kg / t of pig iron) of the adjusted pulverized coal 4 was injected from a single tube lance. The results are shown in Table 4.
表４に示すように、単管ランスで調整微粉炭４を吹込んだ場合と比較して、２重管ランスの内管から微粉炭を吹込み、外管から酸素を吹込んだ場合の方が、着火性を向上させ、燃焼温度を高めることができた。 As shown in Table 4, in the case where the pulverized coal is blown from the inner pipe of the double pipe lance and the oxygen is blown from the outer pipe, as compared with the case where the adjusted pulverized coal 4 is blown with the single pipe lance However, it was possible to improve the ignitability and to raise the combustion temperature.
２重管ランスを用いて微粉炭と酸素とを吹込むことで、微粉炭近傍に酸素を吹込むことができる。これにより、微粉炭から離脱したメタンと酸素とが速やかに反応し、メタン由来の燃焼熱が近接している微粉炭に速やかに伝熱できるようになり、この結果、微粉炭の着火性が向上し、燃焼温度が高くなった。 By injecting pulverized coal and oxygen using a double pipe lance, oxygen can be blown into the vicinity of pulverized coal. As a result, the methane and oxygen released from the pulverized coal react rapidly, and the heat of combustion derived from the methane can be rapidly transferred to the pulverized coal, and as a result, the ignitability of the pulverized coal is improved. And the combustion temperature has risen.
このように、メタンを吸着させて、燃焼性が改善された微粉炭と酸素とを２重管ランスを用いて高炉に吹込むことで、燃焼性が改善されていない微粉炭を吹込んだ場合と比較して高炉の炉内温度を高めることができる。これにより、高炉の炉熱を確保でき、高炉操業における還元材比の低減が実現できる。 Thus, when the pulverized coal whose combustibility is not improved is injected by injecting methane into the blast furnace by using the double pipe lance and injecting the pulverized coal and oxygen whose combustibility is improved. The temperature in the blast furnace can be raised compared to the above. As a result, the furnace heat of the blast furnace can be secured, and reduction of the reducing material ratio in blast furnace operation can be realized.
さらに、このように着火性が向上され、燃焼温度が高められた微粉炭に、着火性が改善されておらず、燃焼温度が高められていない微粉炭を配合した配合微粉炭を高炉の羽口から吹き込んでもよい。この場合に、着火性が改善され、燃焼温度が高められた微粉炭を、全微粉炭量に対して少なくとも１５質量％以上となるように配合することが好ましい。なお、着火性が改善され、燃焼温度が高められた微粉炭を多く配合すれば着火性および燃焼温度が改善された微粉炭を多く含むことになり、より高炉の炉内温度を高められることになる。このため、着火性および燃焼温度が改善された微粉炭の配合率については、下限値を定めれば上限値は定めなくても高炉の還元材比の低減は実現できる。なお、着火性が改善されておらず、燃焼温度が高められていない微粉炭とは、例えば、メタンの吸着量を０．３ｋｇ／ｔ−銑鉄未満とした微粉炭である。 In addition, the pulverized coal in which the ignitability is improved and the combustion temperature is raised in this way is mixed with the pulverized coal in which the ignitability is not improved and the combustion temperature is not raised tuyere of the blast furnace You may blow in from. In this case, it is preferable to mix pulverized coal with improved ignition performance and increased combustion temperature so as to be at least 15% by mass with respect to the total amount of pulverized coal. In addition, if the pulverized coal whose ignition property is improved and the combustion temperature is increased is blended in a large amount, the pulverized coal whose ignitability and the combustion temperature are improved will be contained a lot, and the temperature in the blast furnace can be further raised. Become. For this reason, with regard to the blending ratio of pulverized coal in which the ignitability and the combustion temperature are improved, if the lower limit value is determined, the reduction material ratio of the blast furnace can be reduced even if the upper limit value is not determined. Pulverized coal in which the ignition performance is not improved and the combustion temperature is not increased means, for example, pulverized coal in which the adsorption amount of methane is less than 0.3 kg / t-soot iron.
３８本の羽口を備えた高炉を使用し、微粉炭Ａまたは調整微粉炭１〜４を吹き込んで高炉の操業を実施した実施例について説明する。内容積５０００ｍ３の高炉であって、目標１１５００ｔ／ｄａｙの銑鉄生産量、１５０ｋｇ／ｔ−銑鉄の微粉炭比、送風温度１２００℃、Ｏ２富化＋５．５体積％の条件下で、２重管ランスの内管から微粉炭Ａまたは調整微粉炭１〜４を、外管から酸素を吹込みながら高炉の操業をそれぞれ３日間実施した。微粉炭Ａおよび調整微粉炭１〜４の３日間の平均コークス比（ｋｇ／ｔ−銑鉄）を算出した。この結果を表５に示す。 An embodiment in which the blast furnace is operated using a blast furnace provided with 38 tuyeres and blowing in pulverized coal A or adjusted pulverized coal 1 to 4 will be described. It is a blast furnace with an internal volume of 5000 m 3 , double target under the conditions of target 11500 t / day of pig iron production, 150 kg / t-pulverized coal ratio of pig iron, air temperature 1200 ° C, O 2 enrichment + 5.5 vol% The blast furnace was operated for 3 days while blowing in oxygen from the outer tube to pulverized coal A or adjusted pulverized coal 1 to 4 from the inner tube of the tube lance. The average coke ratio (kg / t-pig iron) for three days of pulverized coal A and adjusted pulverized coal 1 to 4 was calculated. The results are shown in Table 5.
表５において、調整微粉炭２〜４は発明例であり、微粉炭Ａおよび調整微粉炭１は比較例である。表５に示すように、調整微粉炭１では微粉炭Ａと比較してコークス比に変化はなく、還元材比であるコークス比を低減できなかった。調整微粉炭１の着火性および燃焼温度は、微粉炭Ａと同程度であるので、このような微粉炭を用いても微粉炭の燃焼性を改善させることができず、このため、コークス比が低減しなかったと考えられる。 In Table 5, the adjusted pulverized coals 2 to 4 are invention examples, and the pulverized coal A and the adjusted pulverized coal 1 are comparative examples. As shown in Table 5, the adjusted pulverized coal 1 had no change in the coke ratio as compared with the pulverized coal A, and the coke ratio, which is the reducing material ratio, could not be reduced. Since the ignitability and the combustion temperature of the adjusted pulverized coal 1 are similar to those of the pulverized coal A, the flammability of the pulverized coal can not be improved even using such pulverized coal, and hence the coke ratio is It is thought that it did not reduce.
一方、調整微粉炭２および調整微粉炭３は、微粉炭Ａと比較して還元材比であるコークス比が低減した。調整微粉炭２および調整微粉炭３は、微粉炭Ａよりも着火性が向上され、燃焼温度も高い。このような調整微粉炭２または調整微粉炭３を用いることで、微粉炭Ａを用いた場合よりも高炉の炉内温度を高めることができ、これにより、コークス比が低減した。 On the other hand, in the adjusted pulverized coal 2 and the adjusted pulverized coal 3, the coke ratio which is the reducing material ratio was reduced as compared with the pulverized coal A. The adjusted pulverized coal 2 and the adjusted pulverized coal 3 have improved ignitability than the pulverized coal A, and the combustion temperature is also higher. By using such adjusted pulverized coal 2 or adjusted pulverized coal 3, the temperature in the furnace of the blast furnace can be raised more than when pulverized coal A is used, whereby the coke ratio is reduced.
また、調整微粉炭４は、微粉炭Ａと比較して還元材比であるコークス比が大きく低減した。調整微粉炭４は、微粉炭Ａよりも着火性が大きく向上し、燃焼温度も著しく高い。このような調整微粉炭４を用いることで、微粉炭Ａを用いた場合よりも高炉の炉内温度を著しく高めることができ、これにより、コークス比が大きく低減した。 In addition, in the case of the adjusted pulverized coal 4, the coke ratio, which is the reducing material ratio, was significantly reduced as compared with the pulverized coal A. The adjusted pulverized coal 4 has a significantly improved ignitability than the pulverized coal A, and the combustion temperature is also extremely high. By using such an adjusted pulverized coal 4, the temperature in the furnace of the blast furnace can be significantly raised as compared with the case of using pulverized coal A, whereby the coke ratio is greatly reduced.
このように、メタンを０．３ｋｇ／ｔ−銑鉄以上吸着させた調整微粉炭２を２重管ランスの内管から吹き込み、酸素を外管から吹込むことで高炉の還元材比であるコークス比を低減できることが確認された。同様に、比表面積を２．０ｍ２／ｇ以上とした調整微粉炭３を２重管ランスの内管から吹き込み、酸素を外管から吹込むことで高炉の還元材比であるコークス比を低減できることも確認された。 Thus, coke ratio, which is the reducing material ratio of the blast furnace, is obtained by blowing in the adjusted pulverized coal 2 adsorbed with methane of 0.3 kg / t-pig iron or more from the inner pipe of the double tube lance and blowing oxygen from the outer pipe. Was confirmed to be able to reduce Similarly, the pulverized coal 3 having a specific surface area of 2.0 m 2 / g or more is blown from the inner pipe of the double pipe lance and oxygen is blown from the outer pipe to reduce the coke ratio which is the reducing material ratio of the blast furnace It was also confirmed that it could be done.
また、微粉炭の比表面積を２．０ｍ２／ｇ以上とし、メタンを０．３ｋｇ／ｔ−銑鉄以上吸着させた調整微粉炭４を２重管ランスの内管から吹込み、酸素を外管から吹込むことで高炉の還元材比であるコークス比を大きく低減できることが確認された。このように高炉の還元材比を低減することで、高炉操業における還元材使用量を低減できる。 Also, adjust the specific surface area of pulverized coal to 2.0 m 2 / g or more, and inject adjusted pulverized coal 4 with methane absorbed by 0.3 kg / t-or more of pig iron from the inner pipe of double pipe lance, and oxygen from the outer pipe It was confirmed that the coke ratio, which is the reducing material ratio of the blast furnace, can be greatly reduced by blowing from the above. By reducing the reducing material ratio of the blast furnace as described above, the amount of reducing material used in the blast furnace operation can be reduced.
次に、微粉炭Ａに調整微粉炭２および調整微粉炭４を、全微粉炭量に対して所定比率となるように配合した配合炭を作製し、上記と同じ高炉および同じ操業条件下で、当該配合炭および酸素を２重管ランスから高炉に吹込む操業をそれぞれ３日間実施し、平均コークス比（ｋｇ／ｔ−銑鉄）を算出した。表６に調整微粉炭２の配合比率と算出した平均コークス比を示す。また、表７に調整微粉炭４の配合比率と算出した平均コークス比を示す。 Next, a blended coal is prepared by blending the adjusted pulverized coal 2 and the adjusted pulverized coal 4 with the pulverized coal A so as to have a predetermined ratio to the total pulverized coal amount, and under the same blast furnace and the same operating conditions as above The mixed coal and oxygen were blown into the blast furnace from the double tube lance for three days, respectively, to calculate an average coke ratio (kg / t-pig iron). Table 6 shows the blending ratio of the adjusted pulverized coal 2 and the average coke ratio calculated. Table 7 shows the blending ratio of the adjusted pulverized coal 4 and the average coke ratio calculated.
表６に示すように、調整微粉炭２においては、配合比率が１５質量％以上になるように調整微粉炭２を配合することで、コークス比の低減が可能となった。また、表７に示すように、調整微粉炭４においては、配合比率が１０質量％以上になるように調整微粉炭４を配合することでコークス比の低減が可能となった。 As shown in Table 6, in the case of the adjusted pulverized coal 2, the coke ratio can be reduced by blending the adjusted pulverized coal 2 so that the blending ratio is 15% by mass or more. In addition, as shown in Table 7, in the case of the adjusted pulverized coal 4, the coke ratio can be reduced by blending the adjusted pulverized coal 4 so that the blending ratio is 10% by mass or more.
着火性が向上され、燃焼温度が高められた調整微粉炭２および調整微粉炭４は、微粉炭Ａと比較して早く着火する。この着火による燃焼熱は微粉炭Ａに伝熱されるので、これにより、微粉炭Ａに調整微粉炭２または調整微粉炭４が配合された微粉炭全体の着火性が改善され、燃焼温度を高めることができたと考えられる。そして、このような微粉炭をランスを介して高炉羽口から吹込むことで、コークス比の低減が実現できたと考えられる。 The adjusted pulverized coal 2 and the adjusted pulverized coal 4 in which the ignitability is improved and the combustion temperature is increased ignite earlier than the pulverized coal A. Since the heat of combustion by this ignition is transferred to the pulverized coal A, the ignition performance of the whole pulverized coal in which the adjusted pulverized coal 2 or the adjusted pulverized coal 4 is blended with the pulverized coal A is improved and the combustion temperature is increased. It is believed that And it is thought that the reduction of a coke ratio was able to be realized by blowing in such pulverized coal from blast furnace tuyere via a lance.
この結果から、メタンを０．３ｋｇ／ｔ−銑鉄以上吸着させた調整微粉炭２を、微粉炭Ａに１５質量％以上配合することで、還元材比であるコークス比の低減が可能となることが確認された。さらに、メタンを０．３ｋｇ／ｔ−銑鉄以上吸着させ、比表面積を２．０ｍ２／ｇ以上とした調整微粉炭４を、微粉炭Ａに１０質量％以上配合することで、還元材比であるコークス比の低減が可能となることが確認された。このように、着火性が向上されてなく、燃焼温度が高められていない微粉炭Ａも、着火性が向上され燃焼温度が高められた調整微粉炭２または調整微粉炭４を配合することでコークス比の低減が可能となり、微粉炭Ａも有効に利用することができた。 From this result, it is possible to reduce the coke ratio, which is the reducing material ratio, by blending 15% or more by mass with the pulverized coal A of the adjusted pulverized coal 2 in which methane is adsorbed by 0.3 kg / t-pig iron or more. Was confirmed. Furthermore, by mixing 10% or more by mass with pulverized coal A of adjusted pulverized coal 4 in which methane is adsorbed by 0.3 kg / t-pig iron or more and the specific surface area is 2.0 m 2 / g or more, reducing material ratio It was confirmed that a certain coke ratio could be reduced. As described above, the pulverized coal A whose ignitionability is not improved but the combustion temperature is not raised is also coked by blending the adjusted pulverized coal 2 or the adjusted pulverized coal 4 whose ignitionability is improved and the combustion temperature is increased. The ratio could be reduced, and pulverized coal A could also be used effectively.
ここで、微粉炭Ａは、比表面積が２．０ｍ２／ｇ未満であり、メタンの吸着量が０．３ｋｇ／ｔ−銑鉄未満の微粉炭である。このため、表６および表７に示した例において、調整微粉炭２および調整微粉炭４を配合する微粉炭としては、少なくともメタンの吸着量が０．３ｋｇ／ｔ−銑鉄未満の微粉炭であればよい。このような微粉炭であれば、調整微粉炭２または調整微粉炭４を上述したそれぞれの配合率で配合することで、還元材比であるコークス比の低減が可能となることが確認された。 Here, the pulverized coal A is a pulverized coal having a specific surface area of less than 2.0 m 2 / g and an adsorption amount of methane of less than 0.3 kg / t-pig iron. For this reason, in the examples shown in Tables 6 and 7, the pulverized coal to be blended with the adjusted pulverized coal 2 and the adjusted pulverized coal 4 may be a pulverized coal having a methane adsorption amount of at least 0.3 kg / t-pig iron. Just do it. With such pulverized coal, it was confirmed that the coke ratio, which is the reducing material ratio, can be reduced by blending the adjusted pulverized coal 2 or the adjusted pulverized coal 4 at the respective blending ratios described above.
なお、燃焼試験および本実施例において、固体還元材として微粉炭を用いた例を示したが、これに限られない。固体還元材としては、微粉炭、プラスチック、廃タイヤ、ＲＤＦ等の固形燃料、生物に由来する資源である有機性資源、廃木材等の廃材の少なくとも１種であってよい。 In addition, although the example which used pulverized coal as a solid reducing material was shown in the combustion test and the present Example, it is not restricted to this. The solid reducing material may be at least one of pulverized coal, plastics, waste tires, solid fuels such as RDF, organic resources that are organisms-derived resources, and waste materials such as waste wood.
また、燃焼試験および本実施例において、易燃性還元材としてメタンを用いた例を示したが、これに限られない。易燃性還元材としては、メタン（天然ガス）、都市ガス、プロパンガス、水素、転炉ガス、高炉ガスおよびコークス炉ガスの少なくとも１種であってよい。 Moreover, although the example which used methane as a flammable reducing material was shown in the combustion test and the present Example, it is not restricted to this. The flammable reducing material may be at least one of methane (natural gas), city gas, propane gas, hydrogen, converter gas, blast furnace gas and coke oven gas.
１０ 燃焼実験装置
１２ 炉壁
１４ 送風管
１６ ２重管ランス
１８ 羽口
２０ 着火位置
DESCRIPTION OF SYMBOLS 10 combustion experiment apparatus 12 furnace wall 14 air-blowing pipe 16 double tube lance 18 tuyere 20 ignition position
Claims (6)
２重管ランスの内管および外管の一方から、固体還元材１ｋｇ当り易燃性還元材を０．００３ｋｇ以上吸着させた固体還元材を前記高炉羽口から高炉内へ吹込み、
前記固体還元材を吹込んでいない前記２重管ランスの内管または外管から酸素を前記高炉羽口から前記高炉内へ吹込むことを特徴とする高炉操業方法。 A blast furnace operation method in which a solid reducing material is blown from a blast furnace tuyere,
A solid reducing material having at least 0.003 kg of a flammable reducing material adsorbed per 1 kg of solid reducing material is blown into the blast furnace from the blast furnace tuyere from one of the inner pipe and the outer pipe of the double pipe lance,
A blast furnace operation method characterized in that oxygen is blown into the blast furnace from the blast furnace tuyere from the inner pipe or the outer pipe of the double pipe lance without blowing the solid reducing material.
２重管ランスの内管および外管の一方から、比表面積が２．０ｍ２／ｇ以上であり、固体還元材１ｋｇ当り易燃性還元材を０．００３ｋｇ以上吸着させた固体還元材を前記高炉羽口から高炉内へ吹込み、
前記固体還元材を吹込んでいない前記２重管ランスの内管または外管から酸素を前記高炉羽口から前記高炉内へ吹込むことを特徴とする高炉操業方法。 A blast furnace operation method in which a solid reducing material is blown from a blast furnace tuyere,
The solid reducing material having a specific surface area of 2.0 m 2 / g or more and having adsorbed 0.003 kg or more of the flammable reducing material per 1 kg of the solid reducing material from one of the inner pipe and the outer pipe of the double pipe lance Blow into the blast furnace from the blast furnace tuyere,
A blast furnace operation method characterized in that oxygen is blown into the blast furnace from the blast furnace tuyere from the inner pipe or the outer pipe of the double pipe lance without blowing the solid reducing material.
２重管ランスの内管および外管の一方から、固体還元材１ｋｇ当りの易燃性還元材の吸着量が０．００３ｋｇ未満の固体還元材に、固体還元材１ｋｇ当りの易燃性還元材の吸着量が０．００３ｋｇ以上の固体還元材を、全固体還元材量に対して１５質量％以上となるように配合して前記高炉羽口から高炉内へ吹込み、
前記固体還元材を吹込んでいない前記２重管ランスの内管または外管から酸素を前記高炉羽口から前記高炉内へ吹込むことを特徴とする高炉操業方法。 A blast furnace operation method in which a solid reducing material is blown from a blast furnace tuyere,
From one of the double tube lance inner and outer tubes of the adsorption amount of flammable reducing agent per solid reducing agent 1kg within solid reducing agent is less than 0.003 kg, solid reducing agent 1kg per flammable reducing agent The solid reducing material having an adsorption amount of 0.003 kg or more is blended so as to be 15% by mass or more with respect to the total solid reducing material amount, and blown into the blast furnace from the blast furnace tuyere,
A blast furnace operation method characterized in that oxygen is blown into the blast furnace from the blast furnace tuyere from the inner pipe or the outer pipe of the double pipe lance without blowing the solid reducing material.
２重管ランスの内管および外管の一方から、固体還元材１ｋｇ当りの易燃性還元材の吸着量が０．００３ｋｇ未満の固体還元材に、比表面積が２．０ｍ２／ｇ以上であり、固体還元材１ｋｇ当りの易燃性還元材の吸着量が０．００３ｋｇ以上の固体還元材を、全固体還元材量に対して１０質量％以上となるように配合して前記高炉羽口から高炉内へ吹込み、
前記固体還元材を吹込んでいない前記２重管ランスの内管または外管から酸素を前記高炉羽口から前記高炉内へ吹込むことを特徴とする高炉操業方法。 A blast furnace operation method in which a solid reducing material is blown from a blast furnace tuyere,
The solid reducing material having an adsorption amount of less than 0.003 kg of the flammable reducing material per 1 kg of the solid reducing material from one of the inner pipe and the outer pipe of the double pipe lance, has a specific surface area of 2.0 m 2 / g or more The blast furnace tuyere is compounded so that the solid reducing material having an adsorption amount of 0.003 kg or more of the flammable reducing material per 1 kg of solid reducing material is 10% by mass or more with respect to the total solid reducing material amount. Blow into the blast furnace from
A blast furnace operation method characterized in that oxygen is blown into the blast furnace from the blast furnace tuyere from the inner pipe or the outer pipe of the double pipe lance without blowing the solid reducing material.
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