优化COREX-3000竖炉布料的实践

根据COREX-3000投产后竖炉的生产实践,对COREX竖炉动态布料进行了分析和探索,总结了影响竖炉物料粒度分布不均或物料偏析的主要因素,并介绍四种典型竖炉布料模式,分析了不同炉况下布料模式的选择。动态布料器在布料模式和布料档位上的灵活性对疏导平衡还原煤气气流的分布起着决定性的作用。边缘和中心均衡发展的竖炉还原煤气流分布的煤气利用率最高,主要表现在金属化率高,热交换效率高两方面。     

COREX预还原竖炉矿焦混合布料规律

 针对宝钢的COREX-3000预还原竖炉炉顶的万向节布料器矿焦混合布料过程进行了试验研究。基于量纲和谐原理推导了相似准数,并按照1∶5比例建立冷态模型装置,定量考察了物料混合比例对料流宽度、料面形状以及径向料堆结构的影响。研究表明：物料混合比例对料流宽度和料面形状的影响较小,对料堆结构影响显著,随着大颗粒质量分数的增加,料堆堆密度降低,料堆空隙率增大。研究结果对于指导COREX竖炉生产过程的布料规律具有参考价值。     

布料制度对COREX CGD竖炉内气流分布影响的数值模拟

为研究布料制度对COREX CGD预还原竖炉内煤气流分布的影响,本文建立三维数学模型对不同布料制度条件下CGD竖炉内气流速度分布、压差分布及煤气反窜比例进行了模拟研究.计算结果表明,对比中心布料制度,多环布料制度抑制了炉料偏析,使床层空隙度分布更加均匀,改善了竖炉中心煤气分布。多环布料制度增加了炉内压差并抑制了煤气反窜。随着布料档位外移,压差由35 053 Pa增至36 451 Pa,煤气反窜比例由15.64%降至13.68%.     

基于离散单元法模拟引入AGD技术COREX竖炉物料运动行为

基于离散单元法,建立引入Areal Gas Distribution(AGD)技术COREX竖炉物料运动行为的DEM模型.模型计算结果与文献物理实验结果一致,证明模型的合理性.模拟结果显示,AGD竖炉内存在三种类型的流动区域:活塞流区、准停滞区及沟流区.物料运动流型呈现Flat→波浪→W的演变过程.AGD梁下方形成的三角形空隙是还原煤气导入竖炉中心的主要煤气通道.竖炉围管区域AGD梁的安装会影响该区域物料的均匀下降,局部区域的较大法向力可能导致物料的挤压黏结,诱发围管slot堵塞.     

布料模式对COREX预还原竖炉煤气流分布的影响

布料模式决定了炉料的空隙度,而炉料的空隙度分布决定了煤气流的第2次分布。采用三维竖炉数学模型,考察了单环布料情况下,挡位分别在竖炉炉顶直径的0.0、0.8、1.6、2.0、2.4、2.8 m时竖炉内煤气压差和煤气流的变化情况。结果表明：布料过程在料面上发生的炉料粒度偏析对煤气流分布的影响很大,料堆尖处煤气流速很低。随着布料档位外移,竖炉整体压差和围管压差呈现增加的趋势,而反窜煤气比例呈现先微弱降低后迅速增加的趋势,拐点出现在2.0 m布料档位。竖炉炉料布料方式对煤气流有再分配的作用,较为适宜的布料档位为1.6 m,不宜超过2.0 m。     

COREX预还原竖炉煤气流调控技术

重点从竖炉煤气引入方式、布料模式和排料模式三个方面,闸述了COREX预还原竖炉煤气流分布的调控技术。     

对COREX竖炉煤气反窜的初步认识

宝钢生产实践表明,煤气反窜频繁是COREX-3000的特有现象之一,曾是困扰COREX竖炉稳定的主要问题之一。分析煤气反窜与竖炉压差、炉料的温度、排料和金属化率之间的关系,结果表明,煤气反窜对上述参数均带来不利影响,易导致竖炉炉况不稳定。探讨了正常生产及竖炉炉况异常时煤气反窜产生的原因,并介绍了竖炉中心加粉、下降管添加冷却介质两种降低煤气反窜危害的措施的原理。采用上述措施并结合操作调整,煤气反窜量由20%降低至5%左右。     

COREX竖炉结瘤对物料运动行为影响的DEM模拟

为考察COREX预还原竖炉内部结瘤对物料行为的影响,利用离散单元法(DEM)研究了炉内不同位置结瘤对物料运动流型、颗粒应力的影响,并探究了排料速率对炉内物料运动行为的改善作用。模拟结果表明,竖炉围管区发生结瘤,直接影响结瘤附近物料运动轨迹,导致物料运动流型发生变化;同时,相较正常工况,炉内物料间作用力明显增加。当竖炉导流锥产生结瘤时,物料运动流型也明显改变,并且颗粒在结瘤位置下方存在偏析现象;与围管结瘤相比较,炉内颗粒间作用力进一步增加;通过对瘤下方螺旋排料器转速提升,颗粒间作用力显著降低,基本与顺行状态下保持一致。相关研究可为COREX竖炉的优化操作提供指导和理论依据。     

济(南)钢球团竖炉布料车的革新

介绍了历年来济钢对球团竖炉布料车进行的种种改进、包括;布料车作业方式的改进;胶带机的改进;车结构由简支式改悬臂式;以及行走驱动装置落地,并采用液力驱动和链条一钢弗复合牵引方式等。由此,大大提高了竖炉球团产的均匀性和布料工作的稳定性。     

COREX 3000熔融还原炼铁工艺能量利用特征

COREX熔融还原炼铁工艺采用非炼焦煤直接炼铁,解决了当今焦炭资源短缺的问题,缩短了工艺流程,显著减轻了炼铁工业对环境的污染程度;且能生产出与高炉相媲美的优质铁水,生产过程产生的大量优质煤气可用于生产海绵铁或发电等多级利用,成为当代冶金工业的前沿技术。鉴于此,在物料平衡和热平衡计算的基础上,分析了COREX 3000熔融还原炼铁工艺能量利用的特征,指出其降低能耗的方向。     

Mathematical simulation of burden distribution in COREX 3000 shaft by discrete element method

The distribution of reducing gas in a shaft furnace dominates the temperature profile,gas utilization ratio,metallization degree and is the overwhelming factor for stable,high productivities and low-energy-consumption operation.At the same time,the distribution of gas flow is mainly determined by the position of gas inlet,the packed bed porosity distribution as well as its change due to the difference on the mode of top charge and bottom discharge.When injecting position of the process is fixed,the charg...     

Influence of Screw Design on Burden Descending Velocity and Particle Segregation in COREX Shaft Furnace

COREX shaft furnace(SF)is an industrial system that employs screw feeders;thus,the burden descending velocity and particle segregation in the SF can be directly affected by the design of screw.A three-dimensional actual size model of COREX-3000 SF was established using the discrete element method.Four types of burdens,including pellet,ore,flux and coke,were considered in this model.With this consideration,the effect of screw design on solid flow was investigated.Results showed that,in the base case,burdens fell primarily down from the first flight of the screw.The burden descending velocities were nearly uniform in the peripheral direction and decreased along the radial direction.In addition,the normalized particle size increased in the center area and decreased in the wall area.Reducing the flight diameter of screw benefited an even flow pattern and restrained the rolling tendency of burden from the edge to center areas.An optimized case was also proposed,in which a uniform solid flow profile could be obtained and the evenness of descending velocity along the radius could be greatly improved.     

宝钢罗泾COREX C3000冷却系统工艺特点

对宝钢罗泾COREX C3000冷却系统工艺特点进行了阐述.C3000炉体冷却系统主要由冷却壁水系统、工艺水系统和设备水系统三部分组成,是充分吸取了C2000在设计和生产方面的经验教训以及高炉的成功经验而进行设计的,重点对炉体、耐材、炉体冷却系统等方面作了大量改进.     

Influence of Cohesive Zone Shape on Solid Flow in COREX Melter Gasifier by Discrete Element Method

Based on the principle of discrete element method(DEM),a 2Dslot model of a COREX melter gasifier was established to analyze the influence of cohesive zone shape on solid flow,including mass distribution,velocity distribution,normal force distribution and porosity distribution at a microscopic level.The results show that the cohesive zone shape almost does not affect the particle movement in the upper shaft and deadman shape.The particles in the lower central bottom experience large normal force to support the particles above them,while particles around the raceway and in the fast flow zone exhibit weak force network.The porosity distribution was also examined under three kinds of cohesive zones.Like the velocity distribution,the whole packed bed can be divided into four main regions.With the increase of cohesive zone position,the low porosity region located in the root of cohesive zone increases.And the porosity distribution becomes asymmetric in the case of biased cohesive zone.