JP2009228039A - Method for controlling flow rate of gas in bottom-blow converter - Google Patents
Method for controlling flow rate of gas in bottom-blow converter Download PDFInfo
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本発明は、製鋼転炉設備における底吹吹錬時の流量制御を行う底吹転炉のガス流量制御方法に関するものである。 The present invention relates to a gas flow rate control method for a bottom blowing converter that performs flow rate control during bottom blowing in a steelmaking converter.
転炉設備では吹錬を行うために、ガスを炉口からランスを降ろして吹くいわゆる「上吹」と、炉の底にある羽口から吹く「底吹」の２種類を行う。 In the converter equipment, there are two types of blowing, so-called “upper blowing” in which gas is blown from the furnace lance and blown from the tuyeres at the bottom of the furnace.
後者の底吹吹錬では、底吹ガス流量が過大な場合は、羽口の損耗を加速させたり、溶鋼が炉壁に付着する地金の量を増加させるといった不具合が生じる。また逆に、流量が少ない場合は、羽口での溶鋼静圧を維持できなくなるため、羽口から溶鋼が逆流し、転炉の底が抜けてしまうというトラブルに直結する。このため、転炉の操業において底吹ガス流量の制御は溶鋼の品質のみならず、設備保護の観点からも非常に重要な役割を担っている。 In the latter bottom blowing, when the bottom gas flow rate is excessive, there are problems such as accelerating the tuyere wear and increasing the amount of metal that the molten steel adheres to the furnace wall. On the other hand, when the flow rate is small, the molten steel static pressure at the tuyere cannot be maintained, which directly leads to a trouble that the molten steel flows backward from the tuyere and the bottom of the converter comes off. For this reason, in the operation of the converter, the control of the bottom blowing gas flow plays a very important role not only from the quality of molten steel but also from the viewpoint of equipment protection.
すなわち、ガス種切替時、あるいは流量設定変更時の設定値が適切でない場合には、緊急ガス変更という安全処理によるダウンタイムの発生、あるいは羽口の背圧が保てなくなり、転炉の底が抜けてしまうという重大トラブルに直結するという問題がある。特に、底吹ガスの頻繁なガス種変更および設定値変更が行われる場合には、普通鋼吹錬と比較しこの危険性が高くなる。 In other words, if the set value at the time of gas type switching or flow rate setting change is not appropriate, downtime due to safety processing such as emergency gas change or the back pressure of tuyere cannot be maintained, and the bottom of the converter There is a problem that it is directly connected to a serious trouble of losing. In particular, when the gas type change and set value change of the bottom blowing gas are frequently performed, this risk is higher than that of ordinary steel blowing.
これに対処するため、通常の操業では一定の流量設定下限値を設けての操業を行ってる。また、特許文献１には、ガス流量をステップ的に大幅に変更、若しくは、ガス種類を変更する際に、定流量制御から定圧制御に切替え、羽口背圧が予め定めた圧力設定値に達したときに、定圧制御から定流量制御に戻す技術が開示されている。
しかしながら、前記一定の流量設定下限値を設ける操業では、実際には同じ流量であっても羽口の損耗度合い、羽口本数によって背圧は変化してしまうため、安全率を高くした設定値、すなわち種々の操業状態に対処すべく流量設定下限値を高めにせざるを得ないという問題がある。 However, in the operation for setting the fixed flow rate setting lower limit value, even if the flow rate is actually the same, since the back pressure changes depending on the degree of wear of the tuyere and the number of tuyere, the set value with a high safety factor, That is, there is a problem that the flow rate setting lower limit value must be increased to cope with various operating conditions.
また、特許文献１は、ガス流量などの大幅なステップ変化に対する過渡応答特性の改善、すなわち立上げまたは立下げを早くする技術であり、緊急ガス変更という安全処理によるダウンタイムの発生、あるいは羽口の背圧が保てなくなり、転炉の底が抜けてしまうという重大トラブルを避ける技術ではない。 Further, Patent Document 1 is a technique for improving transient response characteristics with respect to a large step change such as a gas flow rate, that is, a technique for quickly starting up or shutting down, generating downtime due to safety processing such as emergency gas change, or tuyere. It is not a technology to avoid serious troubles that the back pressure of the converter cannot be maintained and the bottom of the converter falls out.
本発明では、これら従来技術の問題点に鑑み、底吹吹錬時の流量制御にあたって、緊急ガス変更という安全処理によるダウンタイムの発生、あるいは羽口の背圧が保てなくなり、転炉の底が抜けてしまうという重大トラブルを確実に避けることができる、底吹転炉のガス流量制御方法を提供することを課題とする。 In the present invention, in view of these problems of the prior art, in the flow control during bottom blowing, the occurrence of downtime due to the safety process of emergency gas change or the back pressure of the tuyere cannot be maintained, and the bottom of the converter It is an object of the present invention to provide a gas flow rate control method for a bottom-blown converter that can surely avoid a serious trouble of falling out.
本発明の請求項１に係る発明は、底吹転炉のガス流量制御方法であって、羽口背圧とガス流量との計測値から羽口背圧とガス流量との特性曲線をリアルタイムに求め、求めた特性曲線に基づいて、次回変更予定のガス流量に対する羽口背圧を推定し、推定した羽口背圧に基づいて、次回のガス流量を設定することを特徴とする底吹転炉のガス流量制御方法である。 The invention according to claim 1 of the present invention is a gas flow rate control method for a bottom blow converter, in which a characteristic curve of tuyere back pressure and gas flow rate is measured in real time from measured values of tuyere back pressure and gas flow rate. Based on the obtained characteristic curve, the tuyere back pressure with respect to the gas flow scheduled to be changed next time is estimated, and the next gas flow rate is set based on the estimated tuyere back pressure. This is a gas flow rate control method for a furnace.
また、本発明の請求項２に係る発明は、請求項１に記載の底吹転炉のガス流量制御方法において、前記推定した羽口背圧が溶鋼静圧維持を可能とする背圧下限値以上の場合には、前記次回変更予定のガス流量を次回のガス流量として設定し、前記推定した羽口背圧が前記背圧下限値未満の場合には、前記求めた特性曲線に基づいて、前記背圧下限値以上になるガス流量を求め、求めたガス流量を次回のガス流量として設定することを特徴とする底吹転炉のガス流量制御方法である。 Further, the invention according to claim 2 of the present invention is the gas pressure control method for a bottom blow converter according to claim 1, wherein the estimated tuyere back pressure enables the molten steel to maintain a static pressure. In the above case, the gas flow rate to be changed next time is set as the next gas flow rate, and when the estimated tuyere back pressure is less than the back pressure lower limit value, based on the obtained characteristic curve, A gas flow rate control method for a bottom blow converter, wherein a gas flow rate that is equal to or higher than the lower limit of the back pressure is obtained, and the obtained gas flow rate is set as a next gas flow rate.
本発明によれば、羽口背圧とガス流量との計測値から羽口背圧とガス流量との特性曲線をリアルタイムに求め、求めた特性曲線に基づいて、次回変更予定のガス流量に対する羽口背圧を推定し、推定した羽口背圧に基づいて、次回のガス流量を設定するようにしたので、緊急ガス変更という安全処理によるダウンタイムの発生、あるいは羽口の背圧が保てなくなり、転炉の底が抜けてしまうという重大トラブルを確実に避けることができる。また、次回のガス流量を自動で設定するようにしたので、設定値入力ミスによるトラブル抑止も可能となる。 According to the present invention, the characteristic curve between the tuyere back pressure and the gas flow rate is obtained in real time from the measured values of the tuyere back pressure and the gas flow rate. Estimated mouth back pressure, and set the next gas flow rate based on the estimated tuyere back pressure. The serious trouble that the bottom of the converter falls out and can be surely avoided. In addition, since the next gas flow rate is automatically set, it is possible to suppress troubles caused by setting value input errors.
本発明を実施するための最良の形態について、図と数式を参照して以下に説明を行う。
転炉内への配管を流れるガス流量Ｑは、以下に示す（１）式の関係があることが知られている。
The best mode for carrying out the present invention will be described below with reference to the drawings and mathematical expressions.
It is known that the gas flow rate Q flowing through the piping into the converter has the following relationship (1).
Ｑ＝ａ0＊ＳＱＲＴ（ΔＰ）・・・・・（１）
ここで、ａ0は配管の太さ、長さ羽口の数で決まる定数である。また、ΔＰは圧損であり、転炉内圧をＰo、羽口背圧をＰとすれば、(Ｐ−Ｐo)で求められる。
Q = a 0 * SQRT (ΔP) (1)
Here, a 0 is a constant determined by the thickness and length of the pipe. ΔP is a pressure loss, and can be obtained by (P−Po), where Po is the converter internal pressure and P is the tuyere back pressure.
通常、転炉内圧Ｐoは一定であるので、（１）式は（２）式のように書き換えることができる。 Usually, since the converter internal pressure Po is constant, the equation (1) can be rewritten as the equation (2).
Ｑ＝ａ＊ＳＱＲＴ（Ｐ）・・・・・（２）
ここで、ａは配管の太さ、長さ羽口の数などで決まる定数であり、通常の設備であればａは一定であるが、転炉吹錬の場合羽口は損耗により短くなる事もあれば、本数が変化することもある。このためaの値が変化してしまうので、同じ流量設定であっても羽口での背圧が変化してしまう。
Q = a * SQRT (P) (2)
Here, a is a constant determined by the pipe thickness, the number of tuyere, etc., and a is constant for normal equipment, but in the case of converter blowing, the tuyere becomes shorter due to wear. Or the number may change. For this reason, since the value of a changes, the back pressure at the tuyere changes even at the same flow rate setting.
図２は、羽口背圧とガス流量との特性曲線を説明する図である。縦軸に羽口背圧P、横軸にガス流量Qをとった背圧流量特性を表す曲線であり、羽口の状況変化により、例えば特性A、特性B、特性Cのように特性曲線が変化する。特性Aから特性B、そして特性Cにいくに従って、前述の（２）式中の定数ａの値が大きくなる。 FIG. 2 is a diagram for explaining a characteristic curve of tuyere back pressure and gas flow rate. The vertical axis represents the tuyere back pressure P and the horizontal axis represents the gas flow rate Q. The curve represents the back pressure flow rate characteristic. Change. The value of the constant a in the above equation (2) increases from the characteristic A to the characteristic B and then to the characteristic C.
また、羽口背圧Pには、溶鋼静圧維持のための最低背圧を表す、背圧下限値Pminを示している。この背圧下限値Pmin以下の羽口背圧では、前述したように羽口での溶鋼静圧を維持できなくなり、羽口から溶鋼が逆流し、転炉の底が抜けてしまうというトラブルに至ってしまう。 In addition, the tuyere back pressure P indicates a back pressure lower limit value Pmin indicating a minimum back pressure for maintaining the molten steel static pressure. At the tuyere back pressure below this back pressure lower limit Pmin, the molten steel static pressure at the tuyere cannot be maintained as described above, and the molten steel flows backward from the tuyere and the bottom of the converter comes out. End up.
図２で、例えばガス流量Q0と同じ流量をとったとしても、特性により羽口背圧が、特性Aでは羽口背圧Pa、特性Bでは羽口背圧Pmin、特性Cでは羽口背圧Pｃと特性によりそれぞれ羽口背圧が異なってくることが分る。 In FIG. 2, for example, even if the same flow rate as the gas flow rate Q 0 is taken, the tuyere back pressure depends on the characteristics, the tuyere back pressure Pa in the characteristic A, the tuyere back pressure Pmin in the characteristic B, and the tuyere back in the characteristic C. It can be seen that the tuyere back pressure varies depending on the pressure Pc and the characteristics.
図３は、本発明を適用するための装置概要を説明する図である。図中、１は転炉、２は上吹ランス、３は溶鋼、４は羽口、５は配管、６は圧力計、７は流量調節弁、８は流量計、および９は流量制御装置をそれぞれ表す。 FIG. 3 is a diagram for explaining an outline of an apparatus for applying the present invention. In the figure, 1 is a converter, 2 is a top blowing lance, 3 is molten steel, 4 is tuyere, 5 is piping, 6 is a pressure gauge, 7 is a flow control valve, 8 is a flow meter, and 9 is a flow control device. Represent each.
転炉１中の溶鋼３に、上吹ランス２および羽口４からガスを吹いて吹錬を行っている様子を模式的に表している。羽口４には、配管５を介してガスを供給し、配管５には羽口背圧を測定する圧力計６、ガス流量を計測する流量計８の計測器と、ガス流量を調節する流量調節弁７が配されている。
A mode that gas blowing is blown to the molten steel 3 in the converter 1 from the upper blowing lance 2 and the
流量制御装置９は、圧力計６および流量計８からの計測データを受信して、流量調節弁７に羽口４へ吹き込むべきガス流量を設定する。この流量制御装置９には、通常ＤＣＳが用いられるが、以下で説明を行う処理演算を行えるものであればどのような演算装置を用いても構わない。なお、図中のｈは、転炉１中にある溶鋼３の高さを表しており、この溶鋼高さｈに基づく溶鋼静圧に打ち勝つだけの羽口背圧がなければ羽口から溶鋼が逆流してしまう。
The flow control device 9 receives the measurement data from the pressure gauge 6 and the
図１は、本発明に係る底吹転炉のガス流量制御方法の処理手順例を示す図である。図１に沿って以下に処理を順に説明していくものとする。 FIG. 1 is a diagram showing a processing procedure example of a gas flow rate control method for a bottom blow converter according to the present invention. The processing will be described below in order with reference to FIG.
まず、Step01にて、圧力計および流量計にて背圧とガス流量のそれぞれの瞬時値を計測する。次にStep02にて、計測した背圧とガス流量のそれぞれの瞬時値からリアルタイムに背圧と流量の特性曲線を求める。具体的には、背圧とガス流量から前述の（２）式に基づいて定数ａを計算する。なお、ここからの処理・判断は、流量制御装置にて行われる。 First, in Step 01, each instantaneous value of the back pressure and the gas flow rate is measured with a pressure gauge and a flow meter. Next, in Step 02, a characteristic curve of the back pressure and flow rate is obtained in real time from the instantaneous values of the measured back pressure and gas flow rate. Specifically, the constant a is calculated from the back pressure and the gas flow rate based on the above-described equation (2). Note that the processing / judgment from here is performed by the flow control device.
そして、Step03にて、計算した定数ａに基づく特性曲線を用いて、次回変更予定のガス流量Ｑchに対する羽口背圧Ｐchを推定する。次に、Step04にて、溶鋼静圧維持のための最低背圧を表す、背圧下限値Pminが推定したＰch以下かどうかを判断する。 In Step 03, the tuyere back pressure Pch with respect to the gas flow rate Qch to be changed next time is estimated using the characteristic curve based on the calculated constant a. Next, in Step 04, it is determined whether or not the back pressure lower limit Pmin representing the minimum back pressure for maintaining the molten steel static pressure is equal to or less than the estimated Pch.
背圧下限値Pminが推定したＰch以下である場合には、Step05にて次回変更予定のガス流量Ｑchをそのまま次回のガス流量Ｑnextとして設定する。 If the back pressure lower limit value Pmin is less than or equal to the estimated Pch, the gas flow rate Qch to be changed next time is set as the next gas flow rate Qnext at Step 05 as it is.
背圧下限値Pminが推定したＰch未満である場合には、Step06にて前記計算した定数ａに基づく特性曲線を用いて、背圧下限値Pminから求められるガス流量Ｑminを次回のガス流量Ｑnextとして設定する。 When the back pressure lower limit Pmin is less than the estimated Pch, the gas flow rate Qmin obtained from the back pressure lower limit Pmin is used as the next gas flow rate Qnext using the characteristic curve based on the constant a calculated in Step 06. Set.
１ 転炉
２ 上吹ランス
３ 溶鋼
４ 羽口
５ 配管
６ 圧力計
７ 流量調節弁
８ 流量計
９ 流量制御装置
DESCRIPTION OF SYMBOLS 1 Converter 2 Top blowing lance 3
Claims (2)
羽口背圧とガス流量との計測値から羽口背圧とガス流量との特性曲線をリアルタイムに求め、
求めた特性曲線に基づいて、次回変更予定のガス流量に対する羽口背圧を推定し、
推定した羽口背圧に基づいて、次回のガス流量を設定することを特徴とする底吹転炉のガス流量制御方法。 A gas flow rate control method for a bottom blow converter,
From the measured values of tuyere back pressure and gas flow rate, the characteristic curve of tuyere back pressure and gas flow rate is obtained in real time,
Based on the obtained characteristic curve, estimate the tuyere back pressure for the gas flow scheduled to be changed next time,
A gas flow rate control method for a bottom blow converter, wherein the next gas flow rate is set based on the estimated tuyere back pressure.
前記推定した羽口背圧が溶鋼静圧維持を可能とする背圧下限値以上の場合には、前記次回変更予定のガス流量を次回のガス流量として設定し、
前記推定した羽口背圧が前記背圧下限値未満の場合には、前記求めた特性曲線に基づいて、前記背圧下限値以上になるガス流量を求め、求めたガス流量を次回のガス流量として設定することを特徴とする底吹転炉のガス流量制御方法。 In the gas flow rate control method of the bottom blow converter of Claim 1,
When the estimated tuyere back pressure is equal to or higher than the back pressure lower limit value that enables the molten steel static pressure to be maintained, the gas flow rate to be changed next time is set as the next gas flow rate,
When the estimated tuyere back pressure is less than the back pressure lower limit value, a gas flow rate equal to or higher than the back pressure lower limit value is obtained based on the obtained characteristic curve, and the obtained gas flow rate is determined as the next gas flow rate. A gas flow rate control method for a bottom blowing converter, characterized in that it is set as follows.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108975944A (en) * | 2018-07-20 | 2018-12-11 | 景德镇陶瓷大学 | A kind of preparation method suitable for injection forming organic pore-forming agents and its porous ceramic film material obtained |
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Cited By (1)
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| CN108975944A (en) * | 2018-07-20 | 2018-12-11 | 景德镇陶瓷大学 | A kind of preparation method suitable for injection forming organic pore-forming agents and its porous ceramic film material obtained |
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