共查询到19条相似文献,搜索用时 155 毫秒
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COREX流程主要使用块煤作为燃料,但仍需要加入一定比例的焦炭来支撑熔融气化炉内炉料,保证炉况顺行.块煤裂解形成的半焦和焦炭在熔融气化炉内的劣化程度对煤气流的透气性、渣铁的透气透液性和炉缸热量的分布等影响较大.利用风口取样技术取出风口焦试样,进行粒度分布研究、显微结构分析、透气性指数计算和热态性能测定,发现风口焦试样中大于10mm的较大颗粒多为入炉焦炭劣化所致,小于10mm的小颗粒多为块煤裂解所致;认为块煤挥发分热解后的产物会加剧焦炭的溶损反应,且块煤裂解半焦的反应后强度不及入炉焦炭,半焦在炉内的劣化是影响渣铁透气透液性的主要因素;最后结合对试验结果的分析,给出了降低COREX流程能耗的一些措施. 相似文献
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采用风口取样机对韶钢7号高炉回旋区和死料柱进行取样,对风口回旋区长度、炉芯透气透液性及炉缸活性、炉缸碱金属富集情况等进行了一系列的分析,指出焦炭热强度维持在65以上对高炉强化冶炼至关重要. 相似文献
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通过风口取样,对莱钢1#1 080 m3高炉风口区域焦炭、碱金属以及炉渣成分的变化情况进行了详细的检测分析。结果表明,在高炉结瘤操作时,高炉风口区焦炭粉化严重,死料柱的透气性与透液性差,风口焦炭碱金属含量增加;高炉炸瘤后,随着喷吹煤比的增加,风口焦平均粒度有减小趋势;风口焦样粒度沿高炉径向向炉缸中心减小;风口边缘渣碱度比靠近中心渣碱度低。 相似文献
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相比于高炉风口喷吹富氧热风,熔融气化炉风口采用常温纯氧,使得炉内质量、动量、热量的传输以及煤气流分布等冶炼特征与高炉存在较大差异.通过建立熔融气化炉风口回旋区二维数学模型,系统考察熔融气化炉风口回旋区内速度分布、温度分布及气体组分分布的冶炼特征.结果表明:在气固相热交换及焦炭 (或块煤形成的半焦) 燃烧反应的综合作用下,熔融气化炉风口回旋区内气体温度迅速升高至3 500 K以上;此外,风口前端存在小规模的气体循环流动现象,故风口前端扩孔破损现象严重,进而导致非计划休风率较高;为减少此类休风现象,可适当额外喷吹富氢燃料性气体 (天然气、焦炉煤气),不仅能降低风口回旋区内气体温度,更可替代部分固体燃料,并充分发挥其中H2的高温还原优势,提升熔融气化炉冶炼效率. 相似文献
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高炉作为目前世界上最大的移动床式冶金反应器,保持高炉内良好的透气透液性是保证高炉稳定顺行的关键。高炉内部被软熔带分割开来,分为上部固体散料区和下部固液共存区,下部的固液共存区是决定高炉透气透液性和煤气流分布的重要区域,因此若想明晰高炉影响透气透液性的关键,必须对高炉下部固液共存区的反应进行全面研究。高炉高温区焦炭床与渣铁的相互作用行为是决定铁-焦-渣交互作用及高炉透气透液性的重要因素,调控好液态渣铁与焦炭床的润湿性变化,可以有效改善高炉内部的透气透液性,最终会影响高炉生产效率和稳定性。因此,明晰高炉内渣铁焦的界面润湿行为显得尤为重要。首先对界面润湿现象进行了概述;然后详细从铁水成分以及焦炭性质对铁-焦界面润湿行为的影响进行了总结;其次详细分析了炉渣温度、炉渣成分以及焦炭自身性质对渣-焦界面润湿行为的影响。结果表明,目前高炉内渣铁焦界面润湿行为的研究已经从实验室试验以及基础模拟方面进行了研究,研究结果可为高炉操作者理解高炉内渣铁焦界面润湿行为提供初步理论指导,但仍需在可反映高炉内实际复杂情况的润湿行为变化方面进行深入研究。 相似文献
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The COREX melter gasifier is a countercurrent reactor to produce liquid iron. Directly reduced iron (DRI), noncoking coal,
and other additives are charged to the melter gasifier at their respective temperatures, and O2 is blown through the tuyeres. Functionally, a melter gasifier is divided into three zones: a moving bed, fluidized bed, and
free board. A model has been developed for the moving bed, where the tuyere region is two-dimensional (2-D) and the rest is
one-dimensional (1-D). It is based on multiphase conservation of mass, momentum, and heat. The fluidized bed has been treated
as 1-D. Partial equilibrium is calculated for the free board. The calculated temperature of the hot metal, the top gas, and
the chemistry of the top gas agree with the reported plant data. The model has been used to study the effects of bed height,
injection of impure O2, coal chemistry, and reactivity on the process performance. 相似文献
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Gero Papst 《国际钢铁研究》1989,60(3-4):104-109
Corex process is a smelting reduction process to produce hot metal of blast-furnace quality. Coal is used instead of coke, and this replacement makes production costs of hot metal decrease. Iron ore reduction and melting is separated into two steps: in a melter gasifier reducing gas is generated and melting energy is produced by coal gasification; iron ore is reduced in a shaft furnace. Due to this separation, a great variety of untreated coals can be used. The Corex process is designed to operate under elevated pressure, up to 5 bar. Reducing gas is generated in a fluidized bed by partial oxidation of coal. After leaving the melter gasifier, the gas is mixed with cooling gas to obtain a temperature suitable for direct reduction, i.e. approximately 850–900°C. The fines captured in a hot cyclone are re-injected into the gasifier. Reducing gas is fed into the reduction furnace and ascends through the iron burden according to the counterflow principle. The hot DRI having a temperature of 800–900°C is continuously charged into the melter gasifier, where further reduction is effected and melting occurs. Hot metal and slag drop to the bottom of the melter-gasifier. Analogous to blast-furnace practice hot metal and slag are discharged by conventional tapping. 相似文献
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Coke oven gas (COG), as an environment-friendly source, is projected to be introduced into the COREX process to reduce solid fuel consumption. In this paper, a static model has been developed based on mass and heat balance, which can calculate characteristics of melter gasifier, such as the raceway adiabatic flame temperature (RAFT), volume and component of bosh gas. The results showed that compared with N2, the COG injection from tuyere is more effective on reducing the RAFT and improving the bosh gas volume. The quantity of COG injected is limited for the RAFT, and without other thermal compensation, the largest injection quantity is about 150 Nm3 t?1. The quantity of COG injection can be increased by preheating tuyere oxygen, adjustment of fuel structure and addition of tuyere oxygen. COG injection can promote the reduction and hearth permeability, decrease the RAFT and protect the tuyere, which is beneficial to COREX operation. 相似文献
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为了研究焦炭在风口区域的劣化过程,获取高炉风口区及风口区边缘焦炭样品,利用显微分光光度计和扫描电镜对焦炭与氧化性气体、炉渣和铁水的反应界面形貌与生成物进行了检测,分析了焦炭在风口区的冶金行为。研究结果表明,氧化性气体会以消耗碳元素方式侵蚀焦炭基质,炉渣则会进入焦炭气孔和裂纹中,通过反应、冲蚀和挤压气孔壁的方式瓦解焦炭。铁水主要通过渗碳作用侵蚀焦炭,残留的灰分会覆盖气孔壁表面,阻碍化学反应进行。风口区的焦炭已经高度石墨化,呈现大量片状石墨结构,微观结构的改变导致焦炭强度降低,最终瓦解粉化。焦炭内部的灰分、炉渣颗粒会与炉渣融合,形成终渣。 相似文献
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铁焦与铁矿石混装对高炉初渣形成的影响 总被引:2,自引:0,他引:2
软熔带的形状和位置是影响高炉稳定运行的关键因素之一。研究了综合炉料中混入高反应性铁焦对高炉初成渣形成过程的影响。针对综合炉料进行研究,结果表明,铁焦的加入导致试样的变形开始温度降低,这是由于在较低温度下铁焦即开始与CO2反应,增加了煤气中的CO浓度与平衡浓度的差值,加速了铁矿石的间接还原。铁焦的加入一般使软化结束温度升高、滴落温度下降,使得软熔区间大幅度收窄,表明向铁矿石中混入铁焦能够显著改善高炉料柱的透气性。加入铁焦还使滴落熔铁中的碳含量明显提高。优先考虑对料柱透气性的影响,建议使用加入20%(质量分数)矿粉A的铁焦。 相似文献
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《钢铁冶炼》2013,40(3):195-202
AbstractThe present study has been conducted to investigate the effects of operating conditions, which include gas flowrate, tuyere size, tuyere number, and height of iron phase, on the extent of mixing between molten iron and molten slag in the direct iron ore smelting reduction process. A transparent acrylic water model, 30% of the size of the actual smelter, was constructed to study the mass transfer phenomena. In the water model, water and spindle oil were used to simulate molten iron and molten slag, respectively, while air was used to replace the bottom blown nitrogen gas. In addition, thymol (C10H14O6) was used as a tracer material in the water model, added to the water at the beginning of the experiment. As mixing between water and spindle oil proceeded owing to stirring by the bottom blown gas, the concentration of thymol in the water decreased and that in the spindle oil increased. Water samples were taken from the bottom and 12 cm above the bottom of the water model at various operating times. Concentrations of thymol were then measured using a diode array ultraviolet visible spectrophotometer. By analysing the concentration data, the mass transfer rate kwA, which is a direct index for evaluating the mixing efficiency, could be derived. The process conditions under investigation included 40-500 L min-1 gas flowrate, 0·3-1 cm tuyere size, four or five tuyeres, and 20-30 cm height of the water phase. The test results indicate that when the gas flowrate increases, the value of kwA increases, which indicates better mixing between oil and water phases. However, as the gas flowrate approaches 40 L min-1, the improvement becomes less obvious. The smaller tuyere gives better mixing, and the design of five tuyeres results in better mixing compared with four tuyeres when they are blown with the same total gas flowrate. However, mixing efficiency decreases with increased height of the water phase. Also, as the gas flowrate of bottom blowing approaches 40 L min-1, gas blowing from the top has little effect on the mixing behaviour in the liquid bath. For a four tuyere system, the process conditions of height of oil phase 5 cm, height of water phase 25 cm, diameter of tuyere 0·75 cm, and gas flowrate for each tuyere 40 L min-1, appear to be the optimal design. 相似文献
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LI Hai-feng LUO Zhi-guo ZOU Zong-shu SUN Jun-jie HAN Li-hao DI Zhan-xia 《钢铁研究学报(英文版)》2012,19(9):36-42
COREX process is one of the earliest industrialized smelting reduction ironmaking technology. A numerical simulation model based on discrete element method (DEM) has been developed to analyze the burden distribution in the melter gasifier of COREX process. The DEM considering the collisions between particles can directly reproduce the charging process. The burden trajectory, the location and the burden surface profile are analyzed in melter gasifier with a mixing charging of coal and direct reduction iron (DRI) at the same time. Considering the porosity of packed bed has an important effect on the gas flow distribution of melter gasifier, a method to calculate porosity has been proposed. The distribution of DRI and coal and the porosity in the radial direction are given under different charging patterns, which is necessary to judge the gas flow distribution and provide base data for further researching the melter gasifier for the next work in the future. The research results can be used to guide the operation of adjusting charging and provide important basis for optimizing the charging patterns in order to obtain the reasonable gas distribution. 相似文献
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为了模拟高炉块状带内矿石还原过程对料层透气性的影响,根据实际高炉料层的运动升温及煤气成分的变化情况,设计了模拟矿石在高炉块状带行程的试验方法,建立了能够实时监测料层压差和矿石还原度的试验装置,给出了矿石逐渐升温还原对料层透气性影响的量化评价指标,并实测了某高炉烧结矿、球团矿、块矿、混合矿石在逐渐升温过程中的料层压差和还原度变化,得出逐渐升温还原后的粉化指标和料层压差增加率具有很好的一致性。与原有的低温还原粉化测试方法相比,该方法更适合用于判断高炉整个块状带内矿石还原对料层透气性的影响,更有利于评价矿石性能对高炉操作的影响。试验还研究了原始粒径、还原失重、还原温度、还原时间、加热、转鼓、泡水对矿石粉化程度的影响。 相似文献