Tuyere Level Research Articles

羽口前コークスの性質から検討した高炉出銑比とレースウェイ形状との関係

羽口前コークスの性質から検討した高炉出銑比とレースウェイ形状との関係

高炉でのスラグ, 銑鉄間へのSi, MnおよびSの分配比による炉内下部領域の状態の判定

At the blast furnace hearth, the equilibrium of the partitioning reactions of Si, Mn, and S between the slag and iron is proved not to be attained. Furthermore, the analytical studies of operational data and sample from working furnace indicate that Si transfer to iron occurs at the lower region above the tuyere level through SiO gas, and those of Mn to iron and S to slag occur as slag-metal reactions in the slag layer at the hearth.The attainments of the reaction equilibrium indicate the condition of the lower part of the furnace and are expressed as follows; RSi= (LSi/L°Si) ·100, RMn= (LMn/L°Mn) ·100, and RS= (LS/L°S) ·100, Where Li is the partitioning ratio calculated from the practical data and L°i the equilibrium ratio. The index Rsi shows the thermal intensity around tuyere level suggesting the height of melting zone. The indices RMn and Rs show the oxygen influence in the hearth suggesting the amount of FeO entered as unreduced. In addition to these the iron temperature shows the thermal intensity in the hearth.The furnace operation during a half year at Chiba Works, Kawasaki Steel Corporation has been clearly explained by the use of these indices.

不均一分布を考慮した高炉モデル

In order to clarify the effects of radial distribution patterns of the burdens on the are reduction, heat transfer between gas and solids, and other operational results, a mathematical model taking account of an uneven radial distribution is presented.The blast furnace is divided annularly into center, intermediate and peripheral zones, to all of which the mathematical model presented before can be applied by assuming the plug flow and uniform distribution of gas as well as of burdens. The distribution of gas flow rate to the three zones is regarded to be so determined as that gas pressure is equal everywhere in any horizontal section of the furnace under the radially different gas permeability due to radial distribution of ore/coke ratio. The calculation is carried out so as to make the mean of coke temperatures at the tuyere level equal to a predetermined value under a given o/c distribution.The results of the calculation show that the increase of CO-utilization by about 1.8% and the saving of coke consumption by about 10kg/t-metal may be expected under the condition of uniform distribution in comparison with the distribution pattern in the 22th campaign of the experimental blast furnace.

高炉溶融帯・羽口間の動特性の理論解析

A mathematical model for analysing the dynamic characteristics of blast furnace in the region between melting zone and tuyere level are developed in this paper. On the basis of this model, the fundamental informations on the responses of both the location of melting zone and temperature of molten materials at the tuyere level to the step changes of blast temperature, steam ratio, blast volume and oil-injection rate have been obtained with the aid of digital computer.Three principal time constants, i. e., time constant concerning the accumulation of materials in melting zone, one related to the accumulation of heat in coke zone supposedly located below melting zone and one connected with the shifting process of melting zone, have been taken into account in the analysis. It has been found that the shifting process of melting zone affects severely on the dynamic behavior of blast furnace, since the time constant connected with this process becomes large value such as several hours.

戸畑第1高炉におけるスラグの組成変化

Chemical and mineral composition of samples taken from the peripheral region of the blast furnace at the belly, bosh and tuyere level was examined. In the small lumps from the belly three kinds of primary slag were found, which were considered to correspond to FeO-Al2O3-SiO2, K2O-Al203-SiO2 and CaO-K2O-Al2O3-SiO2, coexisting with the spinel, FeO·(Fe, Al) 2O3, in molten state. Bosh slag which remained in or separated from metallic iron granules consisted only of the CaO-K2O-Al2O3-SiO2 system. Most of the belly and bosh slags bad greater amount of K2O, Al203 and SiO2 than the final slag. The role of minor constituents in ascending gas, i. e. vapors of potassium cyanide and silicon mono-oxide and dusts of some aluminum compounds, is discussed in relation to the process of primary slag formation.

高炉羽口上部の数学的モデル

In order to clarify the behaviors of charged burdens and gases in the blast furnace, a new mathematical model of the upper zone of a blast furnace has been developed in this paper. Considering the rates of reactions reported in the previous work and the heat loss from the peripheral wall, material balances and heat balances are taken around the differential height of beds at an arbitrary position in the furnace and the fundamental equations are obtained as Eq. (1)∼(9). Applying the method of Runge-Kutta-Gill to the numerical calculations, these fundamental equations can be solved by use of a digital computer. Procedures of estimation of temperature, composition and volume rate of flow of gas and temperature of cokes or molten materials at the tuyere level have also been proposed, and these calculations can be developed apart from the fundamental equations mentioned above.

高炉の炉内反応速度

Indirect reduction of iron ores, gasification of cokes, direct reduction of molten wustite, reduction of silica in slag and desulfurization of pig iron have been analyzed and these rates of reactions are determined as the function of properties of materials in the furnace and the operating conditions. For the indirect reduction of iron ores, Eq. (6) of the over-all rate of reduction is obtained, assuming that the diffusion through the gaseous film around the iron ore, the intraparticle diffusion and the chemical reaction proceed in a serial process. Rate determining steps are examined and the results are illustrated in Figs. 3 and 4. For gasification of cokes, using effectiveness factor Ef, the over-all rate of reaction is derived as Eq. (23). Eq. (32) for the rate of reduction of molten wustite is determined, assuming that the reaction is of the second order with respect to wustite in slag. Reduction of silica is analyzed in the upper zone from the tuyere level, and the rate of this reaction is given as Eq. (39). For the desulfurization of pig iron in the hearth, apparent velosity constants are determined as Eq. (45) and (46), considering the reaction between the slag layer and the molten iron flowing through it and the reaction between the layer surface and the iron bath, respectively. These equations of the rate of reaction will be applied to a mathematical model of the blast furnace in the forthcoming reports.

高炉羽口上部の反応工学的解析

高炉羽口上部の反応工学的解析