底吹供气元件的维护实践

介绍了某国内钢铁集团210 t转炉底吹透气元件的维护实践,分析得出底吹透气元件失效的主要原因是底吹透气砖熔损以及透气元件堵塞。通过采取有效的措施,采用初期形成炉渣—金属蘑菇头、中后期控制炉底波动的手段,使整个炉役过程中复吹效果良好。     

武钢二炼钢复吹转炉溅渣护炉及冶金效果分析

简介了武钢第二炼钢厂８０ｔ顶底复吹转炉采用溅渣护炉技术和控制底吹透气元件磨菇头生长的工艺技术,使转炉炉龄和底吹透气砖寿命同步达到了１５２０８炉生产实践;重点讨论了溅渣后随炉龄和底吹透气元件寿命的延长,在炉役中,后期测量碳氧反应、脱磷、脱硫效果及终点残锰仍保持原复吹转炉的冶金特点,表明了采用溅渣护炉技术大幅度提高转炉炉龄后,通过控制炉形,维护好底吹元件仍能保证复吹转炉的冶金效果。     

复吹转炉底吹透气性维护技术研究

研究与实践证明,为确保复吹转炉底部供气在整个炉役过程中的最佳冶炼效果,可灵活调整底部供气参数,保证底吹供气元件透气性非常重要。本钢炼钢厂采用钢铁研究总院开发的底吹专利技术后,共同对确保转炉生产过程中炉底供气元件的透气性进行了深入研究。在底吹供气元件的维护上,采取先进的设备保障、坚持合理的维护制度,保证底吹供气元件寿命与炉龄同步,炉底供气元件在全炉役可见,获得了复吹工艺良好的冶金效果。     

莱钢120t顶底复吹转炉炉体维护技术

介绍了莱钢120t顶底复吹转炉底部供气元件与炉衬实现同步高寿命的方法。选用镁碳质供气砖和双环缝管式喷嘴,均匀分布于炉底同心圆上;根据目标碳含量确定合理的供气制度;通过加长透气砖加快形成金属蘑菇头、针对不同部位采用不同的底吹吹堵技术以及复吹转炉炉体维护特有的维护技术要点。莱钢3座120t顶底复吹转炉首个炉役平均炉龄20000炉以上,最高26668炉,且实现了底吹与炉龄同寿命。     

邢钢48t顶底复吹转炉溅渣护炉实践

介绍了邢钢对48t顶底复吹转炉通过采用溅渣护炉技术,提高复吹转炉炉龄的初步探索,取得了一定效果。认为在保证复吹效果前提下转炉炉龄比设计炉龄大幅度提高,达到了6742炉,炉龄在6300对炉碳氧浓度积平均为0．00289,实现了底吹透气元件寿命与转炉炉龄同步,取得了良好的效果。     

复吹转炉在溅渣下的长寿复吹效果

武钢复吹转炉溅渣护炉工艺技术的开发研究 ,成功地应用于武钢二炼钢转炉 ,最高炉龄达到了 2 2 76 6炉 ,复吹比达到了 10 0 % ,即底部供气元件寿命同步提高到 2 2 76 6炉 ,创造了世界最新记录 ,采用溅渣和辅助溅渣工艺技术 ,促进底吹供气元件表面生成长寿的“炉渣—金属蘑菇头” ,仍保持了复吹的冶金效果 ,碳氧反应接近平衡 ,避免了钢水的过氧化 ,保持了原复吹转炉脱磷、脱硫的能力及终点残锰含量。通过对“炉渣—金属蘑菇头”的研究评估证明 ,具有良好的透气性能。     

国内复吹转炉底吹元件应用研究

介绍了复吹转炉底吹元件的发展概况与分类,以及国内底吹元件在布置位置的优化、结构形式的改进、制造工艺的完善及长寿命维护等方面出现的新技术.指出针对不同炉型优化布置底吹元件及研发新的加工制造工艺延长供气元件的寿命是未来提高转炉复吹比的关键.     

国内复吹转炉底吹元件研究应用现状及展望

介绍了复吹转炉底吹元件的演变,阐述了近年来国内底吹元件在布置位置的优化、结构形式的改进、制造工艺的完善及长寿命维护等方面出现的新技术。指出了针对不同炉型优化布置底吹元件及研发新的加工制造工艺延长供气元件的寿命是未来提高转炉复吹比的关键。对进一步研究转炉复吹有一定的参考和借鉴作用。     

转炉提钒复吹长寿技术研究与应用

针对转炉复吹提钒存在供气能力不足,复吹寿命短,冶金效果不好等问题,开展了底吹透气砖结构优化、底吹供气系统优化设计、复吹提钒工艺及透气砖维护等技术的研究与应用.研究及大量的应用结果表明:采用新技术后可使提钒转炉底吹供气强度提高到0.10 m3/(min·t)以上,提钒复吹长寿化,复吹炉龄大幅提高到7455炉,复吹比100...     

攀钢转炉球形炉底复吹的应用

攀钢转炉原平炉底改球形炉底后，为解决转炉球形炉底应用复吹时出现的问题，分别改进了透气砖的砌筑方法，底部供气系统及供气模式，实现了攀钢３座转炉的复吹，取得了较好的冶金效果。     

钢包底吹气液两相流结构研究

通过水力学模型方法，对弥散型、直通多微孔型和狭缝型３种类型的透气砖底吹时在熔池中所产生的气液两相流结构进行了研究。结果表明，弥散型与直通多微孔型透气砖底吹所产生的气泡行为很接近，而与狭缝型透气砖却有所不同。弥散型和直通多微孔型透气砖底吹时，在熔池中开始产生大气泡，并使流股偏离底吹位置而摆动时的临界流量值高于狭缝型透气砖；弥散型和直通多微孔型透气砖底吹产生的气液两相流扩张角基本一致，而在一定的气体流量下，其扩张角明显大于狭缝型透气砖。     

Numerical Simulation of Fluid Flow and Interfacial Behavior in Three‐phase Argon‐Stirred Ladles with One Plug and Dual Plugs

A numerical investigation is performed to describe the quasi‐steady fluid flow and interfacial behavior in a three‐phase argon gas‐stirred ladle with off‐centered bottom Ar injection through a plug and two plugs placed in 180° and 90°configurations, respectively. The flow of the fluid phase is solved in an Eulerian frame of reference together with the motion of every individually injected Ar bubble, tracked in its own Lagrangian frame. Volume of fluid (VOF) model is used to track any interface between two or more immiscible phases, which include slag/metal, slag/gas and metal/gas. The characteristics of fluid flow in a gas‐stirred ladle with one plug or two plugs configuration are described when the slag layer and the top gas are presented. The slag layer deformation and slag open‐eye formation at different Ar gas flow rates for three types of plug arrangements are given. The comparison of the mixing time, the deformation of slag layer and the behavior of slag/steel interface between one‐plug and two‐plug system is made. Several implications for ladle operational issues during a gas‐stirred ladle refining cycle are discussed. It is found that the proper selection of Ar gas flow rate and plug arrangements during a ladle refining cycle is required for different refining purposes considering the mixing and metallurgical reaction in a three‐phase ladle system.     

210 t LF精炼底吹氩过程气、渣、钢液三相流场优化的数值模拟

基于湍流模型和VOF模型,通过CFD流体工程模拟软件FLUENT6.3.26,对吹氩过程210 t钢包炉(LF)内气、渣、钢液三相流场进行了数值模拟和分析,得出底吹氩孔位(单孔中心,单孔偏心,双孔)和氩气流量(100~500 L/min)对钢液循环流动、渣眼尺寸和卷渣等行为的影响。研究显示,单孔底吹钢包的孔位不同,混合速度和渣眼尺寸不同;渣眼处易卷渣;双孔底吹比单孔底吹死区小得多;氩气流量越大渣眼越大,但渣眼尺寸大于611mm时,其尺寸变化不大;210 t钢包的双孔底吹钢包内合适的吹氩量为200~300 L/min。     

铁矿石烧结箅条糊堵现象成因机制

摘要：箅条糊堵现象是铁矿石烧结生产面临的重要共性问题,给烧结经济技术指标及设备都带来不利影响。为弄清并解决这一问题,首先对箅条糊堵物进行了分类和物相特征分析,随后从原燃料条件、工艺条件和箅条自身性能3个方面综合分析了烧结台车箅条糊堵的形成机制及影响因素,最后基于箅条糊堵物的物相特征及形成机制总结了预防及解决箅条糊堵问题的技术措施和工艺参数控制要求。研究结果对明晰箅条糊堵机制、防治篦条糊堵和促进铁矿石烧结生产稳定有着一定的参考意义。     

Experimental hypoxemic hypoxia: changes in R2* of brain parenchyma accurately reflect the combined effects of changes in arterial and cerebral venous oxygen saturation

PURPOSE: The objective of this study was to develop and evaluate a pulsatile drug delivery system based on an impermeable capsule body filled with drug and an erodible plug placed in the opening of the capsule body. METHODS: The erodible plugs were either prepared by direct compression followed by placing the tablets in the capsule opening or by congealing a meltable plug material directly within the capsule opening. The disintegration/erosion properties of these plugs were determined and optimized for the final delivery system. In order to assure rapid drug release of the capsule content after erosion of the plug, various excipients (fillers, effervescent agents) and drugs with different solubilities were evaluated. The lag time prior to drug release and the subsequent drug release were investigated as function of capsule content, plug composition, plug preparation technique, plug hardness, weight, and thickness. RESULTS: The erosion time of the compressed plugs increased with increasing molecular weight of the hydrophilic polymer (e.g. hydroxypropyl methylcellulose, polyethylene oxide), decreasing filler (lactose) content and decreased with congealable lipidic plugs with increasing HLB-value and inclusion on surfactants. For complete and rapid release of the drug from the capsule body, effervescent agents had to be included in the capsule content. The drug delivery system showed typical pulsatile release profiles with a lag time followed by a rapid release phase. The lag time prior to the pulsatile drug release correlated well with the erosion properties of the plugs and, besides the composition of the plug, could be controlled by the thickness (weight) of the plug. CONCLUSIONS: A single-unit, capsular-shaped pulsatile drug delivery system was developed wherein the pulsatile release was controlled by the erosion properties of a compressed or congealed plug placed within the opening of the capsule opening.     

钢包用透气砖的使用及改进措施

对钢包用透气砖的使用要求和损毁机理进行了分析,并从透气砖的设计、生产工艺、操作条件、冶炼条件等方面分析讨论了透气砖寿命的影响因素,提出了改善透气砖使用情况的措施,同时提出要保证透气砖的安全性,避免在使用的过程中出现非正常倒包现象,甚至漏钢事故。并对透气砖的发展方向进行了探讨。     

精炼钢包底吹透气砖不过气的分析与改进

通过对实际生产中精炼钢包底吹透气砖不过气事故案例进行跟踪取样分析,找出其产生的原因。分析认为狭缝式透气砖气道的堵塞、透气砖表面覆盖有较厚的冷钢、底吹系统的漏气、防漏机构气室不畅通等因素造成了精炼钢包底吹不成功。针对上述因素,采取了相应的改进措施,包括对狭缝参数的调整、透气砖材质的优化、安装预报警装置、吹氩管路的改进、防漏钢机构的调整、座砖和热修补料的优化以及规范操作等。结果表明,因透气砖气道堵塞的发生率降低了76.4%,因透气砖表面覆盖有较厚的冷钢而造成堵塞的发生率降低了55.4%,明显减少了防漏机构漏气和堵塞的事故,取得了良好的效果。     

悬挂挡渣塞在宣钢150t转炉生产中的应用

介绍了宣钢150 t转炉悬挂式挡渣装置的性能、主要参数、工作方式、事故处理,对比了挡渣球出钢挡渣和挡渣塞出钢挡渣的使用效果,最终确定了挡渣塞出钢挡渣工艺。生产实践表明,150 t转炉采用挡渣塞挡渣出钢,可有效控制出钢下渣量,减少钢水回磷,提高了钢水质量和合金收得率,实现了降本增效的目的。     

气体搅拌用透气砖阻力系数的测试

在实验室测定了工业用的狭缝型透气砖进出口压力差及气体出口速度,得出透气砖的阻力系数近似为44/Re,流动状态可近似认为呈层流,阻力系数与相对粗糙度无关,仅是雷诺数的函数,阻力损失与出口速度成正比。从而可计算出透气砖阻力损失,进而确定透气砖气体进口压力。在工业应用中,正常吹氩的压力差不大时,透气砖阻力系数≈0.07。     

Criteria for the Formation of Sediment Plugs in Alluvial Rivers

A sediment plug is defined as aggradation in a river that completely blocks the main channel. Information from documented cases of sediment plug development in alluvial rivers was used to develop criteria for plug formation and to identify the setup conditions for sites that are prone to plug formation. Site characteristics, processes, and associated parameters were evaluated based on a comprehensive literature review and evaluation of data. A plug formation theory was developed and tested using a unique sediment transport/movable bed numerical model that simulates the key processes considered to affect plug formation. The theory and model were calibrated and validated against field data, and then used to develop simplified criteria that can be used to predict plug formation. Findings from this study can be used to identify sites that may be prone to plug formation, and the criteria can be used to evaluate the potential for plug formation based upon field site conditions when data are not available to complete a more detailed study.