高炉喷煤对焦炭质量的要求及改善焦炭质量的途径

高炉喷煤对焦炭的质量要求是：Ｍ４０〉８３％，Ｍ１０〈７％，ＣＲＩ〈２８％，ＣＳＲ〉６０％，平均粒度５０ｍｍ。为了满足高炉大喷煤量对焦炭质量的要求，可以采用配煤技术，装炉煤预处理技术和干熄焦技术来提高焦炭质量。     

焦炭常温强度对锰铁高炉冶炼指标的影响

根据新钢生产实践，运用数理统计方法分析了焦炭常温指标Ｍ４０和Ｍ１０对锰铁高炉利用系数和入炉焦比的数量关系，认为焦炭Ｍ１０对锰铁高炉利用系数、入炉焦比的显著性和敏感度均好于焦炭Ｍ４０，是影响高炉产量和消耗的主要因素。焦炭Ｍ４０、Ｍ１０对产量的影响不如对焦比的影响显著，说明焦炭Ｍ４０、Ｍ１０主要影响焦比。     

富碱焦炭在不同反应条件下的溶损劣化模式

采用高温热还原法制取K、Na蒸汽,并对四种工业焦炭进行了K、Na蒸汽吸附,对富碱焦炭进行了1 100℃恒温和模拟高炉温度制度下的溶损反应劣化研究,分析了碱金属对焦炭溶损反应速率和反应后强度的影响。结果表明,未富碱焦炭的溶损反应率随着温度的升高而加快,CSR_(25%)随反应温度的升高呈现先减小后增大的规律,溶损反应模式为低温均匀反应模式+中温协同模式+高温反应核模式;1 100℃恒温下富碱焦炭的CSR_(25%)都在未富碱焦炭的劣化模式范围内,且K、Na协同富碱焦炭劣化程度最严重;模拟高炉温度制度下富碱焦炭的溶损劣化强度明显高于1 100℃恒温下的富碱焦炭。     

焦炭质量对高炉冶炼的影响

我国十大钢铁企业（除宝钢外）焦炭灰分、Ｍ４０、Ｍ１０和反应后强度等质量指标，与国外的差距较大，已经影响到２０００￣２５００ｍ＾３高炉的技术经济指标。为了满足高炉大型化和富氧大煤量喷吹技术的发展，研究了焦炭质量的有关问题及其对高炉冶炼的影响。     

焦炭常温抗碎强度和耐磨强度与高炉锰铁冶炼指标的关系

根据新钢生产实践支用数理统计方法分析了焦炭常温抗碎强度Ｍ４０和耐磨强度Ｍ１０对锰铁高炉利用系数和焦比的关系，分析结果表明，Ｍ４０、Ｍ１０主要焦比。Ｍ１０是影响锰铁高炉产量和消耗物主要因素。     

鞍钢配型煤炼焦工业炉孔试验

为满足高炉大型化和氧煤大喷吹对焦炭质量提出了更高的要求，进行了鞍钢配型煤炼焦的工业试验，结果表明：（１）在现有生产配煤条件下，配型煤焦炭Ｍ４０提高２．０个百分点，Ｍ１０改善１．２个百分点；（２）在现有生产配煤中多配１２％高挥发分弱粘结性煤的情况下，配型煤焦炭的Ｍ４０提高１．７个百分点，Ｍ１０改善了１．０个百分点（３）提出的鞍钢配型煤工艺流程，可充分利用鞍钢现有设备及设施，比宝钢流程更为简化。     

影响焦高温性能的因素

分析了影响焦炭高温性能的因素,认为焦炭的热性能主要取于焦炭基质的光学组织;焦的气孔结构;焦炭的灰成分（矿物质）等三方面,并针对攀钢的实际情况,提出改善攀钢焦炭的高温性能,首先应用在保证配合煤粘结性、结焦性的前提下,遵循适当多用低煤化度低灰分煤,进一步减少瘦煤配比和降低配煤碱含量（或碱度指数）的原则;其次是4采用备煤新工艺,如配型煤、选掺性粉碎、煤调湿等措施,同时应重视高炉喷吹煤中的碱含量对焦炭的劣化作用,减少入炉料碱含量,降低高炉的碱负荷。     

区分和控制钾、钠对高炉冶炼的不利影响

通过对国内外多座高炉碱金属富集调研结果的统计分析,以及模拟高炉碱富集区域钾、钠对焦炭劣化影响的试验,发现碱富集区域钾蒸气在焦炭上的吸附能力和破坏性都远大于钠,认为高炉现场应严格控制入炉钾负荷,建议将高温下抗碱金属蒸气破坏的能力作为焦炭新增的质量指标,并提出了入炉碱金属上限值的计算公式。     

高炉块状带焦炭劣化机理

 模拟高炉块状带气流和温度条件,研究了粒度、熄焦方式和焦炭类型对焦炭劣化影响,以及高炉上部碱金属K2CO3和Na2CO3催化焦炭与CO2的反应机理。结果表明：小粒度焦炭和湿熄焦炭失碳率较高,产生的粉末量多;捣固焦炭在反应开始时劣化程度低于顶装焦炭,随着反应时间增加,劣化程度高于顶装焦炭;碱金属会与焦炭中的灰分形成催化复合物,导致焦炭与CO2反应的起始温度降低,破坏焦炭的微晶结构,失碳率增加,粉化加重;K2CO3的催化作用高于Na2CO3的催化作用。     

焦炭反应后强度对高炉操作和不同焦炭的影响

1　前　言由新日铁公司提出的一种简易的焦炭反应后强度 (ＣＳＲ)检验方法 ,已逐步在全世界得到采用。与此同时 ,在许多国家 ,尤其是在欧洲 ,对模拟高炉炉况及其对焦炭反应后强度的影响进行了重点研究。2　高炉操作与焦炭反应后强度的关系2 .1　高炉用焦炭的反应后强度焦炭反应后强度标准中的气化条件是反应时间恒定 2ｈ ,在这种条件下 ,焦炭重量平均损失 2 5%～ 30 %。这种恒定反应时间的规定涉及焦炭反应指数 (ＣＲＩ)与焦炭反应后强度 (ＣＳＲ)两者的关系 (见图 1 )。图 1　ＣＳＲ与ＣＲＩ的关系 (Ｒ2 =0 .9)这不能通过高炉鲍氏反应来说…     

超大型高炉风口焦炭取样分析研究

为恢复炉况及探讨超大型高炉冶炼规律,对首钢京唐公司高炉进行了风口焦炭取样分析,研究了其入炉焦炭热强度与焦炭反应性、焦炭冷强度与焦炭耐磨强度之间的关系;探明了风口焦炭的粒度、劣化度及渣铁滞留量;探索了渣铁滞留量与渣铁体积、风口焦炭粒度、煤比及炉渣二元碱度的关系;分析了炉缸径向焦炭粒度分布、风口前高透气性区长度、炉缸透气性等;根据上述研究结果,提出了高炉操作建议并得到应用。实践结果表明:风口焦炭取样分析可以作为高炉操作调整的重要参考。     

2000m3高炉焦炭质量评价

 由于目前还没有一个能综合反映焦炭质量的指标,因此从影响高炉焦比的角度出发,选取了焦炭灰分、硫分,以及M40,M10,CRI,CSR这6个指标并赋予不同的权重对焦炭质量进行评价。从焦炭质量指标、高炉技术经济指标和统计观点阐述了2000m3高炉用焦炭质量的评价方法。首次提出焦炭评分制,并建立了焦炭质量评价模型。同时加入焦炭预估价格、价格差和性价比等参数辅助评价焦炭质量。通过对8种焦炭进行模型验证,结果显示各焦炭质量差异明显,通过对高炉各焦炭配比进行优化之后,炉况运行稳定,焦炭成本降低。     

Effect of Coke Reaction Index on Reduction and Permeability of Ore Layer in Blast Furnace Lumpy Zone Under Non-Isothermal Condition

 Reasonable control on CRI (coke reaction index) is one of the key factors for BF (blast furnace) low-carbon smelting. However, there are contrary opinions. One is increasing CRI to improve reaction efficiency in BF and the other is decreasing CRI to suppress coke degradation in furnace. Different methods are adopted to realize effective catalysis (increasing CRI) and passivation (decreasing CRI) of coke. Simulation tests of coke in BF lumpy zone under gradual temperature rising have been done. Effect of CRI on gas composition, ore reduction, burden column permeability and heat reserve zone′s temperature under non-isothermal condition are studied. Then combined with iron making calculations, a novel BF operation suggestion is proposed as coke nut with small size be catalyzed and mixed with ore while skeletal coke with large size be passivated and separately charged into BF.     

攀钢高炉风口焦特征

从风口焦和入炉焦的粒度组成、热强度、化学成分、气孔率、显微结构强度、石墨化程度等方面进行对比分析。结果表明：攀钢高炉风口焦灰分及灰中TiO2、Fe2O3含量高,碱金属含量低,反应性高,反应后强度很低。     

入炉碱负荷与焦炭劣化的关系

为了研究首钢高炉入炉碱负荷与炉内焦炭劣化的关系,利用碱金属循环富集模型计算碱金属在高炉内的最大富集量及在高炉内部不同部位的分布,然后进行焦炭在不同浓度碱蒸气下的熔损试验,通过反推计算最终得到了在不同入炉碱负荷情况下焦炭劣化的程度。结果表面,钾和钠在首钢高炉内最大的富集量分别为34.89和7.44kg/t,炉内焦炭已经发生严重劣化,反应性CRI为53.14%,反应后强度CSR为61.69%。要想控制住碱金属对首钢高炉的危害,入炉K2O和Na2O质量必须分别限制在0.48和3.11kg/t以内。     

提高焦炭抗碎强度M_(40)的实践

随着高炉的大型化,焦炭抗碎强度M40高低对高炉生产影响越来越大。本文对影响焦炭抗碎强度的各种原因进行了详细分析,通过调整配合煤细度、降低焦炭灰分、改善配合煤质量等措施,使焦炭抗碎强度得到显著提高,为高炉稳定顺行创造了条件。     

The influence of simultaneous adsorption of potassium and sodium vapours on coke structure and performance

Alkali metals are one of the important factors promoting the degradation of coke in blast furnace. Previous studies usually focused on the properties of coke affected, respectively, by K and Na separately, while K and Na will simultaneously affect coke performance in the actual production of blast furnace. Through simulating the actual situation where coke is affected by K and Na vapours simultaneously in blast furnace, the evolution of coke structure and thermal properties (CRI, CSR) after alkalisation with different proportions of K and Na vapours are revealed in this study. Results showed that coke structure was broken when the proportion of alkali vapours reached 3%, and coke fine formation rate increased with the increase of K vapour, indicating that K vapour caused a great damage to coke structure; CRI of coke reached the highest and CSR the lowest when K/Na ratio was 3/7. It was observed with SEM/energy dispersive spectrometer that K and Na existed in both mineral matters and carbon matrix; nepheline, generated when coke reacted with alkaline (K, Na) vapours, was determined by XRD. The content of K and Na in nepheline is dependent on the ratio of alkaline (K, Na).     

Coke Reactivity under Blast Furnace Conditions and in the CSR/CRI Test

The present work aims to study the high‐temperature strength of coke. Mechanisms of disintegration were evaluated using basket samples charged into LKAB's experimental blast furnace prior to quenching and dissection. Coke charged into basket samples was analysed with CSR/CRI tests and compared with treated coke from the blast furnace. Results from tumbling tests, chemical analyses of coarse and fine material, as well as light optical microscopy studies of original and treated coke have been combined and evaluated. The results indicate a correlation between the ash composition and the CSR values. Differences in the texture of the coke were noted with light optical microscopy, and a significant change in the coke texture during the CSR/CRI test conditions was found. The results suggest that the main reaction between coke and CO₂ took place in isotropic areas, which was especially pronounced in coke with a low CSR. Signs of degradation were apparent throughout the coke pieces that have undergone CSR/CRI testing, but were less observable in coke reacted in the blast furnace. The results indicate that reaction with CO₂ is generally limited by the chemical reaction rate in the CSR/CRI test, while in the blast furnace the reaction is limited by the diffusion rate. Coke degradation is therefore mostly restricted to the coke surface in the blast furnace.     

碱金属对钒钛磁铁矿高炉冶炼的影响及对策

分析了碱金属在钒钛磁铁矿高炉冶炼中的循环富集行为、对炉料性能以及高炉冶炼的影响,指出了高炉内碱金属的潜在危害及防止措施.认为:攀钢高炉碱负荷较高,但炉渣排碱能力较强,目前碱害尚未凸现.碱金属对焦炭的破坏作用突出,且近年来劣化趋势明显,应加以重视.通过合理配煤或尝试对焦炭钝化处理,可以在一定程度上改善其热性能,增强焦炭的抗碱侵蚀能力.     

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.