JPH09227921A - Method for blowing gas into molten iron - Google Patents
Method for blowing gas into molten ironInfo
- Publication number
- JPH09227921A JPH09227921A JP3700496A JP3700496A JPH09227921A JP H09227921 A JPH09227921 A JP H09227921A JP 3700496 A JP3700496 A JP 3700496A JP 3700496 A JP3700496 A JP 3700496A JP H09227921 A JPH09227921 A JP H09227921A
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- JP
- Japan
- Prior art keywords
- gas
- flow rate
- inert gas
- blowing
- molten iron
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、溶鉄の精錬を行う
際の溶鉄内へのガスの吹き込み方法に関し、とくに吹き
込みガス流量の可変範囲の広いガスの吹き込み方法に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for blowing gas into molten iron when refining molten iron, and more particularly to a method for blowing gas with a wide variable range of the blowing gas flow rate.
【０００２】[0002]
【従来の技術】近年、鉄鋼精錬においては溶鋼内へのガ
ス吹き込みが常用されるようになってきたが、精錬技術
の高度化、多様化に伴い、一連の精錬工程の中で吹き込
みガスの流量を大幅に変更しうる技術の必要性が高まっ
ている。2. Description of the Related Art In recent years, gas injection into molten steel has become common in steel refining. However, with the sophistication and diversification of refining technology, the flow rate of blown gas in a series of refining processes has been increasing. There is a growing need for technology that can significantly change the size of a device.
【０００３】例えば、上底吹き転炉で低燐の高炭素鋼を
溶製するためには、脱炭吹錬の末期に底吹きガス流量を
絞り、スラグ中の（Ｔ．Ｆｅ）を高めて脱燐を促進させ
る必要がある。また、上底吹き転炉で極低炭素域まで脱
炭するに際しては、脱炭末期に酸素の供給が過剰になら
ないように、極低炭素域で底吹き酸素流量を低減させる
必要がある。[0003] For example, in order to melt low-phosphorus high-carbon steel in an upper-bottom blow converter, the bottom blow gas flow rate is reduced at the end of decarburization blowing to increase (T.Fe) in the slag. It is necessary to promote dephosphorization. In addition, when decarburizing to an extremely low carbon region in the top and bottom blown converter, it is necessary to reduce the bottom blown oxygen flow rate in the extremely low carbon region so that the supply of oxygen does not become excessive at the end of decarburization.
【０００４】また、電気炉においても底吹き精錬が多用
されるようになってきたが、溶解初期の溶鋼量の少ない
時期は、底吹きガス流量を小さくし、溶鋼量が多くなる
溶解中期以降に、底吹きガス流量を増大させる必要があ
る。[0004] In the electric furnace, bottom blow refining has been frequently used. However, in the period when the amount of molten steel in the initial stage of melting is small, the flow rate of the bottom blown gas is reduced and after the middle stage of melting when the amount of molten steel increases. Therefore, it is necessary to increase the bottom gas flow rate.
【０００５】一般に溶鋼中にガスを吹き込む羽口として
は、羽口れんが内に金属製の単管又は二重管ノズルを埋
め込んだものが多く用いられる。しかし、このような管
状のノズルは、ガス流量を低減させた時にノズル内に溶
鋼が差し込んで閉塞するという問題がある。そのために
管状のノズルでは、吹き込みガス流量の可変範囲が狭い
ということが問題であった。Generally, as tuyere for blowing gas into molten steel, a tuyere brick with a metal single tube or double tube nozzle embedded therein is often used. However, such a tubular nozzle has a problem in that when the gas flow rate is reduced, molten steel is inserted into the nozzle and becomes blocked. Therefore, the tubular nozzle has a problem that the variable range of the flow rate of the blown gas is narrow.
【０００６】これに対して、多孔質の耐火物いわゆるポ
ーラスプラグを用いて溶鋼内にガスを吹き込む方法で
は、管状のノズルのような溶鋼の差し込みがないため、
流量を絞ることは可能であるが、吹き込めるガス流量が
少なく、大幅な精錬効果の向上が期待できない。On the other hand, in the method of blowing gas into molten steel using a porous refractory, a so-called porous plug, there is no insertion of molten steel as in a tubular nozzle.
Although it is possible to reduce the flow rate, the flow rate of the blown gas is small and a significant improvement in refining effect cannot be expected.
【０００７】一方、例えば特開昭６２−９６６１２号公
報には、羽口れんが内に多数の金属製の細管を埋め込ん
で（集合管方式）、低流量時に溶鋼の差し込みを起こり
にくくして流量可変巾を広くする方法が開示されてい
る。この方法では、健全に形成されたマッシュルームが
羽口を保護し寿命を延ばす役割を果たしており、通常
は、マッシュルームを健全に形成させるために、細管ノ
ズル１本当たりの不活性ガスの吹き込み流量をノズル断
面積で除した細管ノズル先端における見かけのガス流速
が３００Ｎｍ／秒前後となるようにＣＯ２やＮ2等の不
活性ガスを吹き込んでいる。On the other hand, for example, in Japanese Patent Laid-Open No. 62-96612, a large number of thin metal tubes are embedded in a tuyere brick (collecting pipe system) to make it difficult to insert molten steel at a low flow rate and change the flow rate. A method of widening the width is disclosed. In this method, the healthy mushrooms play a role of protecting the tuyere and extending the life. Normally, in order to form the mushrooms soundly, the flow rate of the inert gas per thin tube nozzle is set to the nozzle. An inert gas such as CO 2 or N 2 is blown in so that the apparent gas flow velocity at the tip of the thin tube nozzle divided by the cross-sectional area is about 300 Nm / sec.
【０００８】この方法でガス流量を大幅に絞ろうとする
と、溶鋼の差し込みは防止できるものの、ガスによる冷
却能が低下し、マッシュルームが溶け落ちて羽口の寿命
が著しく短くなる問題が生じる。ガス流量を大幅に増大
させようとすると、ガスによる冷却が過多となり、マッ
シュルームが異常に成長して、ガス流路が閉塞するとい
う問題が生じる。If the gas flow rate is greatly reduced by this method, the molten steel can be prevented from being inserted, but the cooling capacity due to the gas is lowered, the mushroom melts down, and the life of the tuyere becomes remarkably shortened. If the gas flow rate is to be significantly increased, there is a problem that the cooling by the gas becomes excessive and the mushroom grows abnormally to block the gas flow path.
【０００９】[0009]
【発明が解決しようとする課題】本発明は、上記のよう
な従来技術の問題点に鑑み、羽口の寿命を低下させるこ
となく、不活性ガスの吹き込み流量の可変範囲を大きく
する溶鉄内へのガスの吹き込み方法を提供することを目
的とする。SUMMARY OF THE INVENTION In view of the problems of the prior art as described above, the present invention provides a molten iron in which the variable range of the blowing rate of the inert gas is increased without reducing the life of the tuyere. It is an object of the present invention to provide a gas blowing method of
【００１０】[0010]
【課題を解決するための手段】本発明は上記の課題を解
決するためになされたものであって、その要旨は、不活
性ガスを吹き込んで溶鉄の精錬を行うに際し、健全なマ
ッシュルームが維持されるように、不活性ガスの吹き込
み流量を増加する場合にはＯ2ガスを混合し、および／
または、不活性ガスの吹き込み流量を減少する場合には
プロパン等の炭化水素ガスを混合して吹き込むことを特
徴とする溶鉄内へのガスの吹き込み方法である。The present invention has been made to solve the above-mentioned problems, and its gist is to maintain a healthy mushroom during the refining of molten iron by blowing an inert gas. As described above, when increasing the flow rate of the inert gas, O 2 gas is mixed, and /
Alternatively, it is a method of blowing gas into molten iron, which is characterized in that a hydrocarbon gas such as propane is mixed and blown when the flow rate of the inert gas is reduced.
【００１１】また、単管ノズルもしくは単管ノズルを集
合した羽口から不活性ガスを吹き込んで溶鉄の精錬を行
うに際し、ノズル１本当たりの不活性ガスの吹き込み流
量をノズル出口断面積で除した見かけの線流速が４００
Ｎｍ／秒超となる場合には、下式で示される範囲内の流
量ＱOＮｍ3／時のＯ2ガスを混合して吹き込むことを特
徴とする溶鉄内へのガスの吹き込み方法である。Further, when performing the refining of molten iron by blowing an inert gas from a single pipe nozzle or tuyere where the single pipe nozzles are assembled, the flow rate of the inert gas blown per nozzle is divided by the nozzle outlet cross-sectional area. Apparent linear flow velocity is 400
When it exceeds Nm / sec, it is a method of blowing gas into molten iron, which is characterized by mixing and blowing O 2 gas at a flow rate Q O Nm 3 / hour within the range shown by the following formula.
【００１２】０．１５×（Ｑ−4/3Ｑ*）≦ＱO≦０．２
２×（Ｑ−2/3Ｑ*) ここで、Ｑ ：不活性ガスの吹き込み流量（Ｎｍ3／
時） Ｑ* ：基準吹き込み流量（Ｎｍ3／時）＝300(Ｎｍ／秒)
×ノズル総断面積(ｍ2)×3600 。0.15 × (Q-4 / 3Q *) ≦ Q O ≦ 0.2
2 × (Q−2 / 3Q *) where Q is the flow rate of the inert gas blown (Nm 3 /
Q *: Reference injection flow rate (Nm 3 / hour) = 300 (Nm / sec)
× Nozzle total cross-sectional area (m 2 ) × 3600.
【００１３】また、単管ノズルもしくは単管ノズルを集
合した羽口から不活性ガスを吹き込んで溶鉄の精錬を行
うに際し、ノズル１本当たりの不活性ガスの吹き込み流
量をノズル出口断面積で除した見かけの線流速が２００
Ｎｍ／秒未満となる場合には、下式で示される範囲内の
流量ＱLPGＮｍ3／時のプロパンガスを混合して吹き込む
ことを特徴とする溶鉄内へのガスの吹き込み方法であ
る。Further, when refining molten iron by injecting an inert gas from a single pipe nozzle or tuyere which is a collection of single pipe nozzles, the flow rate of the inert gas blown per nozzle is divided by the nozzle outlet cross-sectional area. Apparent linear flow velocity is 200
When it is less than Nm / sec, it is a method of blowing gas into molten iron, which is characterized in that propane gas having a flow rate Q LPG Nm 3 / hour within a range represented by the following formula is mixed and blown.
【００１４】０．１６×（2/3Ｑ*−Ｑ)≦ＱLPG≦０．２
３×（4/3Ｑ*−Ｑ） ここで、Ｑ ：不活性ガスの吹き込み流量（Ｎｍ3／
時） Ｑ* ：基準吹き込み流量（Ｎｍ3／時）＝300(Ｎｍ／秒)
×ノズル総断面積(ｍ2)×3600 。0.16 × (2 / 3Q * -Q) ≤Q LPG ≤0.2
3 × (4 / 3Q * −Q) where Q: the flow rate of the inert gas blown (Nm 3 /
Q *: Reference injection flow rate (Nm 3 / hour) = 300 (Nm / sec)
× Nozzle total cross-sectional area (m 2 ) × 3600.
【００１５】なお、ここで言う「健全なマッシュルー
ム」とは、羽口先端を保護しつつ、所定のガス流量を安
定して吹き込める流路を有するマッシュルームを意味す
る。また、「不活性ガス」とは、ＣＯ2、Ｎ2、Ａｒある
いはこれらの混合ガスを意味する。The term "healthy mushroom" as used herein means a mushroom having a flow path capable of stably blowing a predetermined gas flow rate while protecting the tuyere tips. Also, the "inert gas" means a CO 2, N 2, Ar or a mixed gas thereof.
【００１６】[0016]
【発明の実施の形態】図１は、本発明を実施する際のガ
スの吹き込み経路の例を示す説明図である。転炉１の底
部に羽口２が埋め込まれており、ガスは混合器３内で混
合された後、羽口２を通って溶鉄４内に吹き込まれる。
通常は、ＣＯ2バルブ５および／またはＮ2バルブ６を開
とし、その他のバルブは閉として不活性ガスのみを吹き
込む。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing an example of a gas blowing path for carrying out the present invention. The tuyere 2 is embedded in the bottom of the converter 1, and the gas is mixed in the mixer 3 and then blown into the molten iron 4 through the tuyere 2.
Normally, the CO 2 valve 5 and / or the N 2 valve 6 are opened, and the other valves are closed to blow only an inert gas.
【００１７】ガスを通常よりも高流量で吹き込む場合
は、Ｏ2バルブ８を開としてＯ2ガスを不活性ガスに混合
してから吹き込む。ガスを通常よりも低流量で吹き込む
場合は、ＬＰＧバルブ７を開としてプロパンガスを不活
性ガスに混合してから吹き込む。なお、図１はＣＯ2と
Ｎ2ガスを使用した場合であるが、不活性ガスとしてＡ
ｒ等の他のガスを使用しても良い。また、プロパンガス
の代わりに、天然ガス等の他の炭化水素ガスを使用して
も良い。When the gas is blown at a higher flow rate than usual, the O 2 valve 8 is opened and the O 2 gas is mixed with the inert gas before being blown. When the gas is blown at a flow rate lower than usual, the LPG valve 7 is opened to mix the propane gas with the inert gas and then blown. In addition, FIG. 1 shows the case where CO 2 and N 2 gas are used.
Other gas such as r may be used. Further, other hydrocarbon gas such as natural gas may be used instead of propane gas.
【００１８】本発明の発明者らは、溶鉄中に不活性ガス
のみを吹き込んで精錬を行う場合に、高流量の不活性ガ
スを流しているとマッシュルームが過度に成長してガス
流路が閉塞気味となり流量が低下してくること、低流量
の不活性ガスを流しているとマッシュルームが溶け落ち
羽口が溶損して寿命が著しく低下すること、ノズル１本
当たりの吹き込み流量をノズル出口断面積で除した見か
けの線流速が２００〜４００Ｎｍ／秒とすれば健全なマ
ッシュルームが形成され羽口の寿命が伸びることを知見
した。すなわち、吹き込みガスによる冷却能がマッシュ
ルームの形成条件を支配する。The inventors of the present invention, when carrying out refining by blowing only an inert gas into molten iron and flowing a high flow rate of the inert gas, the mushroom grows excessively and the gas flow passage is blocked. The flow rate will decrease, and if a low flow rate of inert gas is flowing, the mushroom will melt down and the tuyere will melt and the life will be significantly reduced. It was found that when the apparent linear flow velocity divided by was 200 to 400 Nm / sec, a healthy mushroom was formed and the life of the tuyere was extended. That is, the cooling ability by the blown gas governs the mushroom formation conditions.
【００１９】そこで、発明者らは、見かけのガス線流速
が２００Ｎｍ／秒未満あるいは４００Ｎｍ／秒超となる
ようにガス流量を変更した場合でも冷却能がほぼ一定と
なるようにガス組成を制御すれば健全なマッシュルーム
形成を維持しつつ不活性ガスの吹き込み流量の可変巾
（範囲）を大きくできるとの考えから、見かけの線流速
を４００Ｎｍ／秒超の高流量のガスを吹き込む場合には
発熱反応を伴うＯ2ガスを不活性ガスに混合し、見かけ
の線流速を２００Ｎｍ／秒未満の低流量のガスを吹き込
む場合には分解吸熱反応を伴う炭化水素ガスを不活性ガ
スに混合して吹き込む方法を検討した。Therefore, the inventors of the present invention should control the gas composition so that the cooling capacity becomes almost constant even when the gas flow rate is changed so that the apparent linear gas flow velocity is less than 200 Nm / sec or more than 400 Nm / sec. If it is possible to increase the variable width (range) of the flow rate of the inert gas blown while maintaining a healthy mushroom formation, an exothermic reaction occurs when a high flow rate gas with an apparent linear velocity of more than 400 Nm / sec is blown. A method in which an O 2 gas accompanied by is mixed with an inert gas, and when a low flow rate gas having an apparent linear flow rate of less than 200 Nm / sec is blown, a hydrocarbon gas accompanied by a decomposition endothermic reaction is mixed with the inert gas and blown. It was investigated.
【００２０】不活性ガスを吹き込む場合には、羽口はガ
スの顕熱のみで冷却され、ガスの比熱から冷却能を計算
すると、２５℃のガスを１５００℃の溶鉄に吹き込む場
合、ＣＯ2ガスの場合が１６ kcal／molでＮ2ガスの場合
が約１１ kcal／molとなる。Ｏ2ガスを吹き込む場合に
は、ガスの顕熱増加により羽口が奪われる熱よりも、 Ｏ2＋２Ｃ→２ＣＯ の発熱反応で受ける熱の方が大きく、差し引き約７４ k
cal／molの熱を発生する。従って、ＣＯ2ガスを増加す
る場合にはその増加量の１６／７４＝約０．２２倍のＯ
2ガスを混合し、Ｎ2ガスを増加する場合にはその増加量
の１１／７４＝約０．１５倍のＯ2ガスを混合すれば、
羽口の冷却能が維持される。When an inert gas is blown in, the tuyere is cooled only by the sensible heat of the gas, and when the cooling capacity is calculated from the specific heat of the gas, when blowing the gas at 25 ° C into the molten iron at 1500 ° C, the CO 2 gas In case of N 2 gas, it becomes about 11 kcal / mol. When blowing O 2 gas, the heat received by the exothermic reaction of O 2 + 2C → 2CO is larger than the heat taken by the tuyere due to the increase in sensible heat of the gas, and the subtraction is about 74 k.
Generates cal / mol of heat. Therefore, when the CO 2 gas is increased, 16/74 = 0.22 times as much O
When 2 gases are mixed and N 2 gas is increased, 11/74 = about 0.15 times the increased amount of O 2 gas is mixed,
The tuyere cooling capacity is maintained.
【００２１】また、健全なマッシュルームの形成条件
が、見かけ線流速２００〜４００Ｎｍ／秒であることか
ら、基準流量を Ｑ*(Ｎｍ3／時)＝300(Ｎｍ／秒)×ノズル総断面積(ｍ2)
×3600 と定義すると、不活性ガスのみを吹き込む場合、流量が
２／３Ｑ*以上４／３Ｑ*以下であれば、健全なマッシュ
ルームを維持できる。Since the condition for forming a healthy mushroom is an apparent linear flow velocity of 200 to 400 Nm / sec, the reference flow rate is Q * (Nm 3 / hr) = 300 (Nm / sec) × total nozzle cross-sectional area ( m 2 )
When defined as × 3600, when only the inert gas is blown, a healthy mushroom can be maintained if the flow rate is 2 / 3Q * or more and 4 / 3Q * or less.
【００２２】以上のことから、ＣＯ2ガスを見かけ線流
速が４００Ｎｍ／秒超となる流量Ｑで吹き込む場合、 ０．２２×（Ｑ−4/3Ｑ*）≦ＱO≦０．２２×（Ｑ−2/3
Ｑ*） を満たす流量ＱOでＯ2ガスを混合すれば、羽口の冷却能
がほぼ不変となり、健全なマッシュルーム形成が維持さ
れることになる。From the above, when CO 2 gas is blown at a flow rate Q at which the apparent linear flow velocity exceeds 400 Nm / sec, 0.22 × (Q−4 / 3Q *) ≦ Q O ≦ 0.22 × (Q −2/3
If the O 2 gas is mixed at a flow rate Q O that satisfies Q *), the cooling capacity of the tuyere becomes almost unchanged, and healthy mushroom formation is maintained.
【００２３】同様に不活性ガスとしてＮ2ガスを使用す
る場合、 ０．１５×（Ｑ−4/3Ｑ*）≦ＱO≦０．１５×（Ｑ−2/3
Ｑ*） を満たす流量ＱOでＯ2ガスを混合すれば、羽口の冷却能
がほぼ一定となり、健全なマッシュルーム形成が維持さ
れることになる。Similarly, when N 2 gas is used as the inert gas, 0.15 × (Q-4 / 3Q *) ≦ Q O ≦ 0.15 × (Q-2 / 3
If O 2 gas is mixed at a flow rate Q O that satisfies Q *), the tuyere cooling capacity becomes almost constant, and healthy mushroom formation is maintained.
【００２４】実際には、ＣＯ2とＮ2の混合ガスを不活性
ガスとして使用する場合もあり、Ｏ2ガスの混合量は、 ０．１５×（Ｑ−4/3Ｑ*）≦ＱO≦０．２２×（Ｑ−2/3
Ｑ*） の範囲となる。Actually, a mixed gas of CO 2 and N 2 may be used as an inert gas, and the mixed amount of O 2 gas is 0.15 × (Q-4 / 3Q *) ≦ Q O ≦ 0.22 x (Q-2 / 3
It becomes the range of Q *).
【００２５】一方、プロパンガスを吹き込む場合には、
ガスの顕熱増加により羽口が奪われる熱に加えて、 Ｃ3Ｈ8 → ３Ｃ＋４Ｈ2 の分解反応で奪われる熱があり、合計約７０kcal/molの
冷却能を有する。従って、ＣＯ2ガスを減少する場合は
その減少量の１６／７０＝約０．２３倍のプロパンガス
を混合し、Ｎ2ガスを減少する場合はその減少量の１１
／７０＝約０．１６倍のプロパンガスを混合すれば、羽
口の冷却能が維持される。On the other hand, when blowing propane gas,
In addition to the heat taken away by the tuyere due to the increase in sensible heat of the gas, there is also heat taken away by the decomposition reaction of C 3 H 8 → 3C + 4H 2 , which has a total cooling capacity of about 70 kcal / mol. Therefore, when the CO 2 gas is reduced, 16/70 = about 0.23 times the propane gas is mixed, and when the N 2 gas is reduced, the decrease amount is 11
By mixing / 70 = about 0.16 times the propane gas, the tuyere cooling capacity is maintained.
【００２６】従って、不活性ガス流量を減少して見かけ
線流速が２００Ｎｍ／秒未満となる流量Ｑで吹き込む場
合、健全なマッシュルーム形成を維持するためのプロパ
ンガスの混合量ＱLPGは、Ｏ2ガスの時と同様に考えて、 ０．１６×（2/3Ｑ*−Ｑ）≦ＱLPG≦０．２３×（4/3Ｑ
*−Ｑ） となる。Therefore, when the flow rate of the inert gas is reduced and the apparent linear flow rate is blown at a flow rate Q of less than 200 Nm / sec, the mixed amount Q LPG of propane gas for maintaining sound mushroom formation is O 2 gas. As in the case of, 0.16 × (2 / 3Q * −Q) ≦ Q LPG ≦ 0.23 × (4 / 3Q
* -Q).
【００２７】もちろん、羽口の冷却能は、炉や羽口毎
に、また吹き込みガス種や溶鉄の温度によっても多少異
なり、健全なマッシュルームが形成されるための不活性
ガスの適正流量も異なってくる。従って、本発明を適用
する際には、その炉での不活性ガスの適正流量を把握
し、その適正流量からの増減分の不活性ガスの顕熱を相
殺するだけの冷却能もしくは発熱能を有するように、プ
ロパンガスもしくは他の炭化水素ガスやＯ2ガスの流量
を計算して、混合、吹き込むのが望ましい。Needless to say, the cooling capacity of the tuyere differs slightly depending on the furnace and tuyere, the type of gas blown in, and the temperature of the molten iron, and the appropriate flow rate of the inert gas for forming a healthy mushroom also differs. come. Therefore, when the present invention is applied, the proper flow rate of the inert gas in the furnace is grasped, and the cooling capacity or the heating capacity sufficient to offset the sensible heat of the inert gas that increases or decreases from the proper flow rate. It is desirable to calculate, mix, and blow the flow rate of propane gas or other hydrocarbon gas or O 2 gas so as to have.
【００２８】[0028]
【実施例】容量１００tonの転炉を用いて、本発明のガ
ス吹き込み方法と、不活性ガスのみを吹き込んだ場合の
吹き込み状況と羽口溶損速度を比較した。実施例、比較
例とも直径３mmの小径ノズルをスリーブれんがに１５本
埋め込んだ羽口を炉底に４本配置し、不活性ガスとして
ＣＯ2ガスを使用した。この羽口を使用した場合、本発
明で定義した基準流量Ｑ*は４５８Ｎｍ3／時となる。Ｃ
Ｏ2ガスの流量が１５０、４５０、１５００ Ｎｍ3／時
の３水準で比較を行い、実施例では、１５００Ｎｍ3／
時の場合Ｏ2ガスを２３０Ｎｍ3／時と混合し、１５０Ｎ
ｍ3／時の場合プロパンガスを７０Ｎｍ3／時混合して吹
き込んだ。実施例の結果を表１に、比較例の結果を表２
に示す。EXAMPLE A gas blowing method of the present invention was compared with a blowing condition and tuyere melting loss rate when only an inert gas was blown, using a converter having a capacity of 100 tons. In each of the examples and the comparative examples, four tuyere having 15 small nozzles with a diameter of 3 mm embedded in a sleeve brick were arranged at the bottom of the furnace, and CO 2 gas was used as an inert gas. When this tuyere is used, the standard flow rate Q * defined in the present invention is 458 Nm 3 / hour. C
O 2 flow rate of gas compares with 3 levels of 150,450,1500 Nm 3 / time, in the embodiment, 1500 Nm 3 /
In the case of time, O 2 gas is mixed with 230 Nm 3 / hour,
In the case of m 3 / hour, propane gas was mixed and blown at 70 Nm 3 / hour. The results of Examples are shown in Table 1, and the results of Comparative Examples are shown in Table 2.
Shown in
【００２９】[0029]
【表１】 [Table 1]
【００３０】[0030]
【表２】 [Table 2]
【００３１】比較例の場合には、１５０Ｎｍ3／時の水
準では羽口の溶損進行が速く、実験回数を重ねるにつれ
吹き込み圧力が低下し、１５００Ｎｍ3／時の水準では
羽口が閉塞気味となり吹き込み流量が徐々に低下して最
終的に３００〜４００Ｎｍ3／時までしか吹き込めない
ようになった。In the case of the comparative example, at the level of 150 Nm 3 / hour, the progress of erosion of the tuyere was fast, the blowing pressure decreased as the number of experiments was repeated, and the tuyere became slightly blocked at the level of 1500 Nm 3 / hour. The blowing flow rate gradually decreased, and finally, the blowing rate became 300 to 400 Nm 3 / hour.
【００３２】一方、実施例では、いずれの流量の場合に
も、安定した吹き込みが実現でき、羽口の溶損速度も大
きな変化は認められなかった。従って、本発明の吹き込
み方法によれば、従来の吹き込み方法に比較して、羽口
の寿命低下なしにガス流量の可変範囲を大幅に拡大でき
ることが明らかになった。On the other hand, in the examples, stable blowing could be realized at any flow rate, and no significant change was found in the tuyere melting rate. Therefore, it became clear that the blowing method of the present invention can greatly expand the variable range of the gas flow rate without shortening the life of the tuyere, as compared with the conventional blowing method.
【００３３】[0033]
【発明の効果】本発明により、溶鉄内へのガスを吹き込
みに際し、従来の吹き込み方法と比較して、羽口の寿命
の低下なしに、吹き込みガス流量の可変範囲を大幅に拡
大することが可能となった。According to the present invention, when the gas is blown into the molten iron, it is possible to greatly expand the variable range of the blown gas flow rate as compared with the conventional blowing method without shortening the life of the tuyere. Became.
【図１】本発明を実施する際のガスの吹き込み経路の例
を示す説明図である。FIG. 1 is an explanatory diagram showing an example of a gas blowing path when carrying out the present invention.
１ 転炉 ２ 羽口 ３ ガスの混合器 ４ 溶鉄 ５ ＣＯ2バルブ ６ Ｎ2バルブ ７ ＬＰＧバルブ ８ Ｏ2バルブ1 converter 2 tuyere 3 gas mixer 4 molten iron 5 CO 2 valve 6 N 2 valve 7 LPG valve 8 O 2 valve
Claims (3)
に際し、健全なマッシュルームが維持されるように、不
活性ガスの吹き込み流量を増加する場合にはＯ2ガスを
混合し、および／または、不活性ガスの吹き込み流量を
減少する場合にはプロパン等の炭化水素ガスを混合して
吹き込むことを特徴とする溶鉄内へのガスの吹き込み方
法。1. When refining molten iron by blowing an inert gas, O 2 gas is mixed and / or mixed when increasing the flow rate of the inert gas so that a healthy mushroom is maintained. A method for blowing gas into molten iron, characterized in that a hydrocarbon gas such as propane is mixed and blown when the flow rate of the inert gas is reduced.
羽口から不活性ガスを吹き込んで溶鉄の精錬を行うに際
し、ノズル１本当たりの不活性ガスの吹き込み流量をノ
ズル出口断面積で除した見かけの線流速が４００Ｎｍ／
秒超となる場合には、下式で示される範囲内の流量ＱO
Ｎｍ3／時のＯ2ガスを混合して吹き込むことを特徴とす
る溶鉄内へのガスの吹き込み方法。 ０．１５×（Ｑ−4/3Ｑ*）≦ＱO≦０．２２×（Ｑ−2/3
Ｑ*） ここで、Ｑ ：不活性ガスの吹き込み流量（Ｎｍ3／
時） Ｑ* ：基準吹き込み流量（Ｎｍ3／時）＝300(Ｎｍ／秒)
×ノズル総断面積(ｍ2)×36002. When refining molten iron by injecting an inert gas from a single-tube nozzle or tuyere assembled from single-tube nozzles, the flow rate of the inert gas blown per nozzle is divided by the nozzle outlet cross-sectional area. Apparent linear flow velocity is 400 Nm /
If it exceeds seconds, the flow rate Q O within the range shown by the following formula
A method for blowing gas into molten iron, which comprises mixing and blowing O 2 gas at Nm 3 / hour. 0.15 x (Q-4 / 3 Q *) ≤ Q O ≤ 0.22 x (Q-2 / 3
Q *) where Q is the flow rate of the inert gas blown in (Nm 3 /
Q *: Reference injection flow rate (Nm 3 / hour) = 300 (Nm / sec)
× Nozzle total cross-sectional area (m 2 ) × 3600
羽口から不活性ガスを吹き込んで溶鉄の精錬を行うに際
し、ノズル１本当たりの不活性ガスの吹き込み流量をノ
ズル出口断面積で除した見かけの線流速が２００Ｎｍ／
秒未満となる場合には、下式で示される範囲内の流量Ｑ
LPGＮｍ3／時のプロパンガスを混合して吹き込むことを
特徴とする溶鉄内へのガスの吹き込み方法。 ０．１６×（2/3Ｑ*−Ｑ）≦ＱLPG≦０．２３×（4/3Ｑ
*−Ｑ） ここで、Ｑ ：不活性ガスの吹き込み流量（Ｎｍ3／
時） Ｑ* ：基準吹き込み流量（Ｎｍ3／時）＝300(Ｎｍ／秒)
×ノズル総断面積(ｍ2)×３６００3. When refining molten iron by injecting an inert gas from a single-tube nozzle or tuyere assembled from single-tube nozzles, the flow rate of the inert gas blown per nozzle is divided by the nozzle outlet cross-sectional area. Apparent linear flow velocity is 200 Nm /
If it is less than a second, the flow rate Q within the range shown by the following formula
A method for blowing gas into molten iron, characterized in that LPG Nm 3 / hr propane gas is mixed and blown. 0.16 x (2 / 3Q * -Q) ≤ Q LPG ≤ 0.23 x (4 / 3Q
* -Q) Here, Q: Inflow rate of inert gas (Nm 3 /
Q *: Reference injection flow rate (Nm 3 / hour) = 300 (Nm / sec)
× Nozzle total cross-sectional area (m 2 ) × 3600
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3700496A JPH09227921A (en) | 1996-02-26 | 1996-02-26 | Method for blowing gas into molten iron |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3700496A JPH09227921A (en) | 1996-02-26 | 1996-02-26 | Method for blowing gas into molten iron |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09227921A true JPH09227921A (en) | 1997-09-02 |
Family
ID=12485567
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3700496A Pending JPH09227921A (en) | 1996-02-26 | 1996-02-26 | Method for blowing gas into molten iron |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09227921A (en) |
-
1996
- 1996-02-26 JP JP3700496A patent/JPH09227921A/en active Pending
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