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1.
Sung Sil Park Nurzhan Dyussekenov H.Y. Sohn 《Metallurgical and Materials Transactions B》2010,41(1):51-62
The top-blow injection technique of a gas–solid mixture through a circular lance is used in the Mitsubishi Continuous Smelting
Process. One of the inherent problems associated with this injection is the severe erosion of the hearth refractory below
the lances. A new configuration of the lance to form an annular gas–solid jet rather than a circular jet was designed in the
laboratory scale. With this new configuration, solid particles leave the lance at a much lower velocity than the gas, and
the penetration behavior of the jet is significantly different than with the circular lance in which the solid particles leave
the lance at the same high velocity as the gas. The results of cold model tests using an air-sand jet issuing from a circular
lance and an annular lance into a water bath showed that the penetration of the annular jet is much less sensitive to the
variations in particle feed rate as well as gas velocity than that of the circular jet. Correlation equations for the penetration
depth for both circular and annular jets show agreement among the experimentally obtained values. 相似文献
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《钢铁冶炼》2013,40(8):599-606
AbstractThe transport phenomena in injection lance and the penetrability of solid particles into liquid metal at the lance tip during injection treatment was analysed by a one-dimensional mathematical model developed in this work. Mechanic interactions and heat transfers between a solid particle, carrier gas, lance and/or hot metal have been incorporated in the model. Temperatures and velocities of carrier gas and solid particles were examined for a typical hot metal desulphurisation process by granulated magnesium injection. The temperature of gas increases by several hundred degrees, while that of solid magnesium particles only by several degrees in the lance. The gas velocity is increased by thermal expansion in lance. At the lance tip, the magnesium particle velocity is slower than the gas velocity. The penetrability of a magnesium particle into the hot metal at the lance tip was analysed. 相似文献
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采用Fluent软件模拟了50 t转炉四孔变角和非变角氧枪气体射流,研究了喷孔倾角对氧气射流流场和流股融合距离的影响。结果表明,在距喷头出口距离较近时,各流股独立为自由射流,随着距喷头出口距离的增加,各流股不断扩张,并在一定距离时融合成单股射流;非变角喷头A的流股融合距离为1.3 m,与冷态水模实验得出枪位1.3 m时炉口溅出量最大是一致的;变角氧枪B至I的对角喷孔倾角不同,射流流股融合了两次,大大降低了炉口溅出量;变角氧枪对角喷孔倾角相差0.5°较对角喷孔倾角相差1°时更有利于射流融合距离的增加;在研究喷孔倾角10.5°~11.5°/12.5°的9个喷头中,倾角11°/11.5°的喷头H射流融合距离最长,其理论炉口喷溅量最少。 相似文献
4.
Top-blow injection of a gas?Csolid jet through a circular lance is used in the Mitsubishi Continuous Smelting Process. One problem associated with this injection is the severe erosion of the hearth refractory below the lances. A new configuration of the lance to form an annular gas?Csolid jet rather than the circular jet was designed in this laboratory. With this new configuration, the solid particles fed through the center tube leave the lance at a much lower velocity than the gas, and the penetration behavior of the jet is significantly different from that with a circular lance where the solid particles leave the lance at the same high velocity as the gas. In previous cold-model investigations in this laboratory, the effects of the gas velocity, particle feed rate, lance height of the annular lance, and the cross-sectional area of the gas jet were studied and compared with the circular lance. This study examined the effect of the density and size of the solid particles on the penetration behavior of the annular gas?Csolid jet, which yielded some unexpected results. The variation in the penetration depth with the density of the solid particles at the same mass feed rate was opposite for the circular lance and the annular lance. In the case of the circular lance, the penetration depth became shallower as the density of the solid particles increased; on the contrary, for the annular lance, the penetration depth became deeper with the increasing density of particles. However, at the same volumetric feed rate of the particles, the density effect was small for the circular lance, but for the annular lance, the jets with higher density particles penetrated more deeply. The variation in the penetration depth with the particle diameter was also different for the circular and the annular lances. With the circular lance, the penetration depth became deeper as the particle size decreased for all the feed rates, but with the annular lance, the effect of the particle size was small. The overall results including the previous work indicated that the penetration behavior of an annular jet is much less sensitive to the variations in operating variables than that of a circular jet. Correlation equations for the penetration depth that show good agreements with the measured values have been developed. 相似文献
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Teruyoshi Hiraoka Kazuo Ohnuki Hiromu Fujii Kazuhisa Fukuda Yousuke Hoshijima 《国际钢铁研究》2003,74(8):474-479
Mixed gas of liquefied natural gas (LNG) and oxygen was injected into the vacuum vessel during non‐decarburization period using a multifunctional lance. Tthis study reports the experimental results when applying this process in a 100‐ton piece of equipment and reports the changes in temperature of the refractory surface and molten steel. Using a multifunctional lance allowed heat supplementation by injecting LNG‐oxygen mixed gas into the vacuum vessel of a RH device and then burning the gas near the outlet of the injection nozzle. The following was found: The minimum surface temperature required so that the skull would not adhere to the RH vessel was calculated as about 1643K (1370°C). When the interior of the RH vacuum vessel was preheated with a multifunctional lance so that the temperature would be higher than this, skull adhesion to the vessel did not occur. Calculation of heat balance for burning under atmospheric pressure showed that about 70% of the heat quantity of burning was supplied to the refractory. When mixed gas was burned during the RH process, it was shown from the temperature change of molten steel that about 52% of the burning heat was transferred to the steel. Heat quantity removed through lance cooling water was proportional to the charge length of the lance, and emissivity ε was equivalent to heat transfer quantity of 0.38. 相似文献
7.
Liangcai Zhong Yingxiong Zhu Maofa Jiang Zhengping Qu Yishan Za Xingyu Bao 《国际钢铁研究》2005,76(9):611-615
The effects of a conventional lance tip with 4 normal nozzles and a lance tip with 4 twisted nozzles on slag splashing were investigated. A cold model for LD converters, Jiuquan Iron & Steel Co., was established and the amount of slag splashed onto the model walls was measured in the cold modelling experiments. The results from the experiments show that at low top gas flow rate the amount of slag splashing for the tip with twisted nozzles is less than that for the conventional tip, whereas at high top gas flow rate the amount of slag splashing for the nozzle twisted lance is greater than that for the conventional lance. For the nozzle twisted lance tip, slag splashing rates increase with increase in slag amount, lance height and top gas flow rate and the maximum amount of slag splashing for the tip with twisted nozzles can be obtained under the process parameters of 47.6 Nm3/h gas flow rate, 12% slag amount and 247 mm lance height. More slag droplets can be directed onto the cone with a nozzle twisted lance tip than with a normal lance tip at high top gas flow rate. 相似文献
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A fundamental aspect of submerged powder injection into melts which is not well understood is the extent to which the particles separate from the carrier gas upon injection, particularly under high solids loading conditions. In this study, the injection of nonwettable powders was investigated using a cold-model system at solids loadings from 1 to 25. Polyethylene powder was injected through a top-submerged lance into a cylindrical water bath under bubbling conditions. Air was used as the carrier gas. The apparatus was designed so that the particles remaining with the gas phase could be collected separately from those which escaped from the bubbles. The gas velocity (5.15 to 10.3 m/s), surface tension (0.03 to 0.072 N/m), lance diameter (4.7 to 7.4 mm), and particle size (< 500 μm) were independently varied. The separation of the powder from the primary gas bubbles was found to increase with increasing solids loading when the gas velocity, surface tension, and lance diameter were held constant. At constant solids loading, the separation increased with increasing gas velocity, increased with increasing lance diameter, and decreased with increasing surface tension. The separation was found to be independent of the particle size of the powder in the range of solids loadings tested. A theoretical relationship between the penetration efficiency and the particle jet Weber number successfully correlated with the experimental data. 相似文献
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P. S. Kharlashin A. K. Kharin R. D. Kuzemko R. F. Kalimullin E. V. Protopopov 《Steel in Translation》2013,43(12):783-787
The influence of the powder concentration, carrier-gas pressure, particle density, the equivalent diameter and shape of the particles, the difference in speed of the solid and gas phases, and their dynamic slip on the aerodynamic drag in the guniting lance, the force between the solid and gas phases, the content of gas phase, and the terminal velocity is established by means of a static model of the two-speed motion of the gassuspension in the lance. 相似文献
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对副枪、炉气分析相结合在半钢炼钢中使用存在的问题进行讨论,通过生产试验,提出在冶炼中期利用炉气分析曲线指导过程控制与操作,预报炉渣返干与喷溅,进行过程控制动态炼钢。在吹炼后期,CO与CO2曲线交叉后(即w(C)<0.20%时),炉气分析C预报较准确,利用其进行终点碳控制,实现不倒炉炼钢。在吹氧量为80%~85%与停吹氧30 s后,副枪使用T或TS探头进行测量,对炉气分析模型温度进行修正,可提高炉气分析模型终点温度控制的准确性,减少副枪探头成本消耗。当入炉条件信息不准确时,副枪与炉气分析相结合使用是较合理的选择。 相似文献
12.
G. A. Irons 《Metallurgical and Materials Transactions B》1987,18(1):105-117
Nitrogen and silica particles of 30, 130, and 450 μm average diameters were injected at solid-to-gas loadings up to 280 kg/m3 into liquid lead at 400°C through a steel lance equipped with four thermo-couples. The lance was positioned adjacent to a
transparent wall in the lead retort so that the flow patterns could be photographed. It was found that 130 and 450 μm particle
injection produced bubling in the lead and clogging at high loadings, while the 30 μm particles produced jetting with no clogging.
Analysis of the thermocouple responses permitted the determination of the heat transfer coefficients at the inner and outer
lance surfaces. The inner surface heat transfer coefficient increased with loading, whereas the one at the outer surface was
independent of loading. A two-phase, unsteady-state, one-dimensional model was developed for momentum and heat transfer in
the lance permitting the calculation of gas and particle velocities, volume fractions, and temperatures as well as the lance
temperatures. Using the experimentally determined heat transfer coefficients, it is shown that the gas and particles are heated
only 20 to 40 K in the lance. Nevertheless, this is a large heat demand which chills the lance so that clogging will occur
in the bubbling regime. 相似文献
13.
One way to further utilise produced gases in an integrated metallurgical plant is to replace oil with gas as a reducing agent in a modern blast furnace. Accordingly, it is of great interest to study the injection of reducing gas into the blast furnace. Therefore, a three‐dimensional mathematical model has been developed which simulates the injection of the gas by lances into the tuyere. The model includes the coupled solution of the flow field and the chemical reaction of the gases in the tuyere. Two different types of fuel gas, coke oven gas (COG) and basic oxygen furnace gas (BOF) have been modelled using one injection lance. The modelling technique is presented and discussed as well as the implied results. Furthermore, process parameters such as different gas compositions etc. are investigated using the developed model. Not surprisingly, the main results show that the COG is combusted more completely than BOF gas, which leads to higher flame temperature of the blast putting demand forward to lower the heat load of the tuyere. However, the modelling of the raceway is as far not included in the model, hence the influence of the outlet boundary condition at the tuyere is not reflected in the presented results. 相似文献
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A water model of top and bottom blown converter with top lance powder injection and bottom tuyere powder injection was established to investigate the powder injection. The results show that the powder penetration ratio under the condition of top lance injection is greater than that under the condition of bottom tuyere powder injection. In both cases, the powder penetration ratio increases with the increase of solid/gas ratio and powder particle size. Powder uniform dispersion time with top lance powder injection is longer than that with bottom tuyere powder injection. Top lance powder injection, lance height of 258?mm, bottom blowing rate of 1·96?Nm3?h?1 and powder particle size of 0·212–0·380?mm are suggested as the optimum powder injection operation under the experimental condition. The corresponding optimum operation for prototype is top lance powder injection with lance height of 1550?mm, powder size of 1–5?mm and bottom blowing rate of 450?Nm3?h?1. 相似文献
17.
根据180 t转炉的实际生产情况,以修正的Froude准数为相似准数,建立几何相似比10 : 1水模型,进 行了四孔对称单纯底吹试验,并在最佳的底吹工艺参数下(底吹最佳位置为喷嘴所在同心圆直径:转炉熔池直径= 0. 3处;最佳流量为0. 7 m3/h,均混时间18. 2 s),通过改变顶吹氧枪的气体流量和吹炼枪位进行了顶底复吹转炉射 流与熔池作用的试验。结果表明,在底吹条件下,增加顶吹工艺(最佳枪位150 mm,最佳流量39 m3/h),熔池平均 的均混时间减少了 5.6 s, 180 t转炉顶底复吹可显著提高经济效益。 相似文献
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某冶炼厂的超大型底吹炉运行了5年,通过大修期间统计炉体各部分炉砖的侵蚀情况,提出了控制氧枪压力、炉温、渣型和铜锍品位等优化措施,使炉砖烧蚀速度大幅减慢.此外,就转炉操作容易出现事故,存在场环境恶化、尾气超标、结焦脱落卡住膜式壁、氧枪堵塞的问题,提出底吹炉转炉作业前要对炉体进行安全检查,随炉转动角度的变化及时调整氧枪压力... 相似文献
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在对高炉局部富氧喷煤直吹管内气固两相流流场研究的基础上 ,对直吹管内氧和煤粉的浓度场进行了数值研究 ,包括氧 -煤喷枪的插入角度和枪位、局部富氧射流的漩流数以及煤粉粒度的影响。结果表明 ,氧 -煤喷枪的插入角度和枪位对氧 ,特别是对煤粉的浓度场分布有较大的影响 ;合适的富氧率下氧气的旋流作用能够促进氧气与煤粉的混合 ,增强氧 -煤喷枪出口附近区域的动量传输和质量传输 ;利用氧 -煤喷枪可以形成一个局部富氧区域 ,显著提高煤粉周围的氧浓度 ,促进煤粉的快速燃烧 相似文献