高炉中心加焦对气流分布及煤气利用的影响

中心加焦可以减小中心区域的矿焦比,增加中心气流强度,形成倒V形软熔带,提高料柱的透气性;由于中心气流中CO含量高,焦炭的溶损少,颗粒进入炉缸时保持较大的粒度,提高死焦堆的透气透液性。中心加焦对高炉操作有很多积极作用,但中心加焦也会减小中心气流的利用率,提高燃料比。当中心加焦过量时,高炉内的气流分布出现异常,因此需要研究合理的中心加焦量以及中心加焦方式。利用Ergun公式,对不同中心加焦量条件下,高炉内的煤气分布、压差变化等参数进行计算,并根据煤气分布情况简单计算了中心加焦对高炉内煤气利用率的影响。根据计算分析结果,对高炉中心加焦量及中心加焦方式进行讨论。研究结果可以为实际高炉中心加焦操作提供理论参考。     

高炉原燃料分级布料过程及时序

针对目前高炉原燃料质量恶化导致料柱压差升高的现状,寻求通过布料改善料柱透气性的方法.研究表明:不同粒径颗粒的混合会减小散料层的空隙度,降低透气性;减少颗粒混合,可以提高空隙度.为了改善散料层的透气性,研究了原燃料按颗粒大小分级布料的方式、不同粒级炉料的装料顺序及周期,同时分析了串罐、两并罐及三并罐无钟炉顶的布料特点.研究结果对降低高炉料柱压差及保障高炉稳定顺行有重要作用.     

高炉使用含碳复合炉料的原理

 高炉炼铁正朝着高产、低污染、低能耗的方向发展,为了实现这一目标,包括高炉使用含碳复合炉料等一些革新的炼铁技术已经被提出或实际应用。铁焦、热压含碳球团是将铁矿粉和煤粉按一定比例混合后制成的新型含碳复合炉料。研究结果指出,含碳复合炉料相比于传统的高炉炉料（烧结矿和球团矿）具有高温强度高、还原性能好以及原料适应性强等优势。阐明了高炉使用含碳复合炉料的基本原理,介绍了铁焦制备的工艺流程及应用情况,重点进行了热压含碳球团制备工艺流程、冷态冶金性能、高温冶金性能、高炉使用热压含碳球团等试验研究,最后利用多流体高炉数学模型对高炉使用热压含碳球团操作进行了模拟研究。研究表明,高炉使用一定量的含碳复合炉料可以降低热空区温度,增加产量,降低焦比,高炉热利用效率明显提高,操作性能得到有效改善。     

Effect of mixing charge of highly reactive semicoke nut on the reaction of high Al2O3 ferrous burden in blast furnace

In order to improve the performance of blast furnace ironmaking when using the high Al₂O₃ iron ore, the technology of mixing charge of high reactive semicoke nut with ferrous burden was proposed and systematically investigated at laboratory scale in the present paper. The CO₂ gasification activation energy of semicoke ranged from 136.5 to 150.3?kJ?mol^?1, which was lower than that of the traditional coke. At the temperature of 1200°C, the reduction degree of ferrous burden increased a little with the addition of semicoke nut and the consumption ratio of semicoke was 14.0?wt-% under the simulated blast furnace ironmaking condition. The mixing charge of semicoke could obviously reduce the softening beginning temperature, increase the melting temperature and improve the permeability compared with the standard and traditional coke mixing charge samples. During the total softening and melting process, about 90?wt-% of the semicoke nut and 45?wt-% of the traditional coke nut were consumed, respectively. The experiment results indicated that the mixing charge of high reactive semicoke nut could obviously improve the performance of blast furnace ironmaking when using high Al₂O₃ ferrous burden and the semicoke was more effective than traditional coke.     

并罐式无钟炉顶装料模式对料面炉料分布的影响

 为研究装料模式对并罐高炉料面炉料分布的影响,建立了国内某5 500 m3实际高炉并罐式无钟炉顶系统全模型,利用离散单元法分别对矿（A）-矿（B）-焦和矿-焦两种装料模式下炉料从矿焦槽运动至料面全过程进行数值计算,对比分析了装料模式对料面炉料分布的影响。结果表明,由于A矿与B矿布入料面时落点轨迹不重合,导致两种装料模式下料面炉料分布不同。在料面径向上,装料模式对料面矿石体积分布和矿焦比分布影响较小。在料面周向上,矿-矿-焦装料模式和矿-焦装料模式下料面矿石体积分布标准差分别为0.133和0.147,矿-矿-焦装料模式和矿-焦装料模式下料面矿焦比分布标准差分别为0.074和0.086,矿-矿-焦装料模式下矿石体积分布和矿焦比分布更均匀。     

Effect of coke reactivity and nut coke on blast furnace operation

Abstract

Two measures for coke saving and increase in blast furnace efficiency related to coke characteristics – reactivity and size – are discussed in this paper. Modern blast furnace operation with low coke rate and high injection rate causes a change in coke quality requirements. A discussion has arisen recently about highly reactive coke. Here, a theoretical analysis of influence of coke reactivity on the thermal reserve zone, direct reduction and carbon consumption in the blast furnace has been undertaken. Experiments have been performed using non-standard test scenarios that simulate coke behaviour under real blast furnace operating conditions. Coke reactivity and microstructure have also been investigated under the impact of alkali and pulverised coal ash and char. Operation of many blast furnaces has proved the possibility of coke saving and increase in productivity when using small-sized coke (so-called nut coke) mixed with the burden, but the reasons for this phenomenon, and consequently the limit for nut coke consumption, are still not very clear. An analytical method and cold model simulations have been used to quantify the change in shaft permeability and furnace productivity when using nut coke.     

Fundamental research on iron coke hot briquette – A new type burden used in blast furnace

In order to improve blast furnace efficiency, reduce CO₂ emission and accelerate energy utilisation, a new preparation process of iron coke hot briquette (ICHB) based on the raw materials conditions in China, a new type blast furnace ironmaking burden, was experimentally investigated in this paper. The new preparation process was researched and optimised through single factor experiment and orthogonal experiment. Meanwhile, the reactivity and the post-reaction strength of ICHB prepared under the optimised conditions were tested and the effect of ICHB on the thermal performance of conventional coke was researched. In addition, softening and dripping properties of mixed burden with optimised ICHB charging was simultaneously investigated. The results showed that the optimised preparation parameters of ICHB include 15% iron ore, 65% bituminous coal, 350°C hot briquetting temperature, 1100°C carbonisation temperature and 4 hours carbonisation time. The reactivity and the post-reaction strength of ICHB prepared under the optimisation conditions are 62.4 and 10.6%, respectively. ICHB has protective effect on conventional coke and the protective effect is more obvious with 10% ICHB adding. With the increase of ICHB charging ratio, softening interval T₄₀–T₄ of mixed burden is widened while melting interval T_D–T_S (namely cohesive zone) is narrowed. Additionally, the permeability of mixed burden becomes better and dripping ratio is first increased then decreased. The suitable charging ratio of ICHB in mixed burden is about 30%.     

攀钢高炉焦丁混装入炉生产实践

介绍了攀钢高炉开展矿石、焦丁混装入炉的研究和生产情况 ,焦丁回收混装入炉设施充分利用了本厂现有设备 ,工程投资少见效快。用焦丁代替冶金焦与矿石混装入炉不但节省焦炭降低生产成本 ,而且有利于钒钛矿冶炼 ,使高炉稳定高产。     

兰炭替代部分焦炭对焦炭层透液性的影响

为探究高反应性兰炭替代部分焦炭加入高炉的可行性,文章通过对气化后的焦炭和兰炭进行冷、热态透液性试验,获得液体在焦床中的流动速度、滴落量及滞留量.结果表明,在高炉上部气化阶段,高反应性兰炭对焦炭有一定的保护作用.在冷态滴落实验中,小粒径燃料条件下,随着兰炭比例的增加,液体滴落速度变缓,滴落量降低16.8％.当兰炭粒度增加...     

JFE应对高炉低质量原燃料的技术措施

介绍了JFE为应对低质量烧结矿和焦炭而开发的技术措施,包括三并罐无料钟炉顶、高焦炭混装比和在高炉中使用部分金属化炉料等技术。使用三并罐无料钟炉顶,可以在使用大量细粒烧结矿和低质量焦炭时,仍能保持低还原剂比和高利用系数操作。提高焦炭混装比可以扩大原料选择范围,加大低价矿的使用比率。在焦炭混装比为120kg/t情况下,发现炉身透气性阻力较大降低,炉身效率得到提高。在技术经济指标保持不变的情况下,对铁矿石原料的要求可以降低。介绍了这些技术的开发背景及其应用效果,也简介了在低质量炉料时,使用金属化炉料降低还原剂比和保持高炉顺行的效果。     

Reduction of Pellets‐Nut Coke Mixture under Simulating Blast Furnace Conditions

In recent years an intensive work has been carried out to decrease the coke losses of the blast furnace through mixing small‐sized coke called “nut coke” in the iron ore burden layers. In order to clarify the influence of nut coke on the pellets reducibility, industrial iron ore pellets were reduced with and without nut coke participation under different temperatures and atmospheres. Isothermal and non‐isothermal reduction tests under simulating blast furnace conditions were performed using an experimental laboratory rig. Furthermore, reflected light microscopy, scanning electron microscopy and X‐ray technique were applied to characterize the microstructure and different phases developed in the origin and reduced pellets. Pellets reduced isothermally without nut coke participation exhibited reduction retardation (RR) at elevated temperature (≥1373 K) whereas the presence of nut coke had a positive effect of preventing such phenomena. The non‐isothermal reduction of pellets showed that, as the amount of nut coke in pellets bed increased, the reducibility of pellets increased, too. The rate controlling mechanism of pellets and pellets‐nut coke mixtures was predicted from the correlation between apparent activation energy calculations and microstructure examination.     

济钢2^#1750m^3高炉取消中心加焦布料模式探索

介绍了济钢2#1750m3高炉在经济炉料结构条件下,取消中心加焦布料模式所做的试验及探索,这种炉料冶金性能比较差,通过优化送风制度,在维持中心加焦的布料模式前提下,拓宽边缘平台,拉宽角差,适当平铺,近中心环带适当增加矿焦比,形成了窄而畅通的中心气流,综合控制了边缘软熔带根部高度,缩小了软熔带层宽度,改善了高炉透气性。     

Fundamental Study on Carbon Composite Iron Ore Hot Briquette Used as Blast Furnace Burden

Carbon composite iron ore hot briquette (CCB) is the product of fine iron ore and fine coal by hot briquetting process, which attracts more and more attention as a new type of ironmaking raw materials aiming to improve the operation efficiency and reduce the coke consumption of blast furnace. This paper is devoted to experimental study on metallurgical properties of CCB and numerical simulation of the BF operation with CCB charging. At first, the metallurgical properties of CCB, including cold crushing strength, RDI, RSI, reducibility, high temperature strength, and softening and dripping are experimentally tested and compared with the common burdens, which revealed that the CCB possesses the required metallurgical properties and is suitable to use as the blast furnace burden. Then, the effects of charging CCB on the dripping properties of comprehensive burdens are elucidated based on the experiments under simulated blast furnace conditions. The results showed that the maximum charging ratio of CCB in the iron burdens is 40%–50% for achieving appropriate dripping properties of the mixed burdens. Finally, a multi‐fluid blast furnace model is used to simulate BF operation with CCB charging. According to model simulations, charging CCB will cause the temperature level to decreases in the furnace and the location of the cohesive zone shifts downward. On the other hand, the productivity tends to increase while coke rate and total reducing agent rate decrease, the heat efficiency improves remarkably and the operation performance of BF is effectively enhanced.     

高炉块状带透气性试验分析

通过试验研究了在不同球团矿配比、不同烧结矿粒度和不同料层厚度条件下,高炉块状带透气性指数的变化规律。粒度小于10 mm的烧结矿会使高炉块状带的透气性急剧变差;在保持料层炉料粒度组成不变的情况下,如果料层厚度增加,则高炉块状带的透气性降低;随着球团矿配比的增加,料层压差呈先升高后趋于稳定的状态,高炉块状带透气性升高。     

莱钢2号1880 m~3高炉炉役后期稳定炉况生产实践

针对莱钢2号1 880 m~3高炉炉役后期生产特点,2013—2015年逐步采用了加长风口、优化布料制度和球团、生矿及焦丁平铺的技术措施,达到了稳定炉况、优化指标的目的。实际生产结果表明,加长风口长度有利于活跃炉缸中心,但需要上下部制度的配合;焦丁平铺后布在靠近炉墙位置,有利于改善边缘矿层的透气性,改善边缘矿石的还原,促进边缘气流的稳定和炉体软水水温差的稳定,有利于降低炉体热量损失,进而有利于降低高炉消耗。     

高炉中心加焦炉料分布机理及布料方式探讨

 针对当前常见的中心加焦装料过程,建立了布料过程中螺旋布料时溜槽内炉料颗粒复合运动的三维数学模型,并建立了炉料颗粒在空区内下落过程数学模型和在炉内堆积所形成料面形状及其径向矿焦比分布数学模型。通过将模型预测料面形状与高炉开炉实测料面形状进行对比,证明了模型的有效性。基于实际高炉参数,计算了13°完全中心加焦和20°小角度中心加焦时炉料落点分布和径向矿焦比分布。结果表明,由于中心加焦过程中部分炉料会分布在中间环带,使得实际中心加焦量减少,两者有效的中心加焦率分别为49.4%和70.4%,且在前者模式下形成了直径约为1.2 m的贯通的中心焦柱区域,而在后者条件下形成中心直径约为2.5 m的较大范围的低矿焦比分布柱状区域。最后,阐述了中心加焦技术原理,指出了当前中心加焦操作方式存在的问题,并探讨了高效布料方式,对指导实际高炉生产操作有着重要意义。     

芜湖新兴铸管1#高炉低硅冶炼操作实践

介绍了芜湖新兴铸管1#高炉采取优化炉料结构、稳定烧结矿碱度、保证入炉原料的冶金性能,提高焦炭质量、合理上下部调剂、改善高炉透气及透液性,坚持使用高风温、富氧喷吹相结合、做到风温、富氧、喷煤的合理匹配和协调互补,提高操作技能等多种措施,进行低硅冶炼的操作实践.不仅提高了生铁质量,而且取得了降硅、节焦、增产的良好经济效益.     

高炉冶炼预还原炉料能耗分析

 通过建立高炉冶炼预还原炉料数学模型,计算了原料铁品位、预还原炉料金属化率和铁的存在形态对高炉冶炼能耗的影响,比较了高炉冶炼预还原炉料和传统高炉的能耗。计算结果表明：针对不同铁品位原料,有一个适合高炉冶炼的炉料最佳金属化率,使高炉冶炼焦比最低;预还原炉料中的铁以硅酸铁形式存在时,主要进行直接还原,冶炼焦比较高;与传统高炉相比,高炉冶炼预还原炉料,可以大幅度降低焦比,但燃料比升高。     

焦炭质量对高炉炉况的影响

由于新钢5#、6#焦炉干熄焦(9#高炉入炉配比50%)变为水熄焦,焦炭冷强度M40下降约4%,造成9#(2500m3)高炉料柱透气、透液性变差,压量关系紧张,炉况波动较大,甚至悬料。通过上下部调剂相结合稳定炉况,加强管理保证生产,高炉炉况逐步恢复。     

Some Challenges and Opportunities in Blast Furnace Operations

Blast furnace iron making faces a lot of pressure to decrease use of metallurgical coke and carbon footprint. In many shops around the world in the meanwhile, the convectional blast furnace process is being run at near optimum efficiency for a given set of raw material conditions. Efforts are therefore being made to generate innovative ideas. Top gas recycling and nitrogen-less blowing seem to be attracting attention. Efforts are continuing for increased pulverized coal injection (PCI) to decrease coke consumption. Several furnaces experience pressure drop problems when trying to increase coal injection due to poor burden quality. The present paper attempts to analyze few of the issues related to top gas recycling in a conventional practice and those of pressure drop during PCI. Recycling of top gas even without removal of CO₂ seems to hold possibilities for enhanced PCI though with worse fuel rate. Managing layer structure and the reactivity of coke particles can be addressed in various ways to improve bed permeability.