Extracting the core indicators of pulverized coal for blast furnace injection based on principal component analysis

An updated approach to refining the core indicators of pulverized coal used for blast furnace injection based on principal component analysis is proposed in view of the disadvantages of the existing performance indicator system of pulverized coal used in blast furnaces. This presented method takes into account all the performance indicators of pulverized coal injection, including calorific value, igniting point, combustibility, reactivity, flowability, grindability, etc. Four core indicators of pulverized coal injection are selected and studied by using principal component analysis, namely, comprehensive combustibility, comprehensive reactivity, comprehensive flowability, and comprehensive grindability. The newly established core index system is not only beneficial to narrowing down current evaluation indices but also effective to avoid previous overlapping problems among indicators by mutually independent index design. Furthermore, a comprehensive property indicator is introduced on the basis of the four core indicators, and the injection properties of pulverized coal can be overall evaluated.

Micromorphology and safety properties of meager and meager-lean coal for blast furnace injection

Four types of meager and meager-lean coal and one type of high-quality anthracite were selected based on the safety requirements for blast furnace coal injection and domestic coal quality to conduct microstructure and component analyses.The analyses of the organic and inorganic macerals and the chemical compositions of the selected coal samples indicate that the four types of meager and meager-lean coal have low volatilization,low ash content,and low sulfur content;these qualities are suitable for blast furnace injection.Grindability test was conducted on the four types of meager and meager-lean coal and the anthracite mixed coal samples.Results indicate that the mixture of meager and meager-lean coal and anthracite is beneficial to improve the grindability of pulverized coal.The explosive tests reveal that the selected coal samples are non-explosive or weakly explosive.When the proportion of meager and meager-lean coal is less than 40wt%,the mixed coal powder would not explode during the blowing process.The minimum ignition temperature test determines that the minimum ignition temperatures of the four types of meager and meager-lean coal and anthracite are 326,313,310,315,and 393°C,respectively.This study provides a guiding research idea for the safety of meager and meager-lean coal used in blast furnace injection.

A novel model for cost performance evaluation of pulverized coal injected into blast furnace based on effective calorific value

The combustion process of pulverized coal injected into blast furnace involves a lot of physical and chemical reactions. Based on the combustion behaviors of pulverized coal, the conception of coal effective calorific value representing the actual thermal energy provided for blast furnace was proposed. A cost performance evaluation model of coal injection was built up for the optimal selection of various kinds of coal based on effective calorific value. The model contains two indicators: coal effective calorific value which has eight sub-indicators and coal injection cost which includes four sub-indicators. In addition, the calculation principle and application of cost performance evaluation model in a Chinese large-scale iron and steel company were comprehensively introduced. The evaluation results finally confirm that this novel model is of great significance to the optimal selection of blast furnace pulverized coal.

Fundamental Study on Coke Degradation in BF with Oxygen Enriched Blast and High Hydrogen Atmosphere

The effects of gas composition, temperature, ore to coke ratio and prereduction rate of ore on coke degradation were studied. The results showed that 1% increment in solution loss of coke reduces coke strength by 0.6%, and the coke degradation is accelerated with the temperature. The higher the temperature, the more coke surface is involved in reactions, and the less negative effect on coke strength is. Hydrogen exerts stronger effect on coke degradation than CO at high temperature. The coke degradation is decreased with the reduction of ore to coke ratio and increase of ore prereduction rate.

3D model study of coal/coke combustion in a blast furnace effects of coal properties

A three-dimensional mathematical model of the combustion of pulverized coal and coke has been developed.The model is applied to the blowpipe-tuyere-raceway-coke bed region in an ironmaking blast furnace in one computational domain,which includes two parts:pulverized coal combustion model in the blowpipe-tuyere-raceway cavity and the coal/coke combustion model in the surrounding coke bed.The effects of coal properties are examined comprehensively,in terms of coal burnout and gas species distributions.The results indicate that using a coal of fine particle size or high VM content could improve burnout and would affect the gas composition considerably.The burnout is examined in two ways:compared with burnout along tuyere axis,burnout over the raceway surface is a more sensitive and sensible parameter to describe the amount of unburnt char entering the coke bed.The model is useful for examining the flow-thermo-chemical characteristics of the pulverized coal injection (PCI) process under various conditions in a blast furnace.

Hot Blast Flow Measurement in Blast Furnace in Straight Pipe

This article shows an innovative method to model and validate the hot air flow through the blast furnacés tuyeres. This study will be the basis for flow measurements implementation and safety interlocks for the pulverized coal injection. The flow measurements were taken in the blast furnace down leg pipes by installing refractory Venturi tubes. The system for the calculation of differential pressure takes into consideration the dimension of the Venturi, the air density and compressibility. The objective is to specify the flow transmitters required to automate a control system and implement safety interlocks for the coal injection plant.

The Advancement in Intensified Smelting Technology of Baosteel Blast Furnace

Baosteel always aims at becoming one of the most profitable enterprises in the world, enjoying international competence, benchmarking with the world advanced level,pursuing innovation sustainable development. Recent years, Baosteel Iron-making Department has caught the opportunity of increasing steel demand; conquering disadvantages such as changeable up-stream market, fuel and raw material’s tight supplies and lower quality, etc. In our department, Major technical problems have been overcome, blast furnace intensified smelting technology improved, the cost of molten iron under control, blast furnace long-life span control technology made breakthrough, and Baosteel’s ironmaking capacity improved further.

包钢高炉喷吹煤粉利用率的测定

利用透射光偏光显微镜,对包钢高炉重力除尘灰、旋风除尘灰和布袋除尘灰中的碳素种类进行定性和定量分析,以测定高炉喷吹煤粉利用率。测定结果表明,3号高炉喷吹煤粉利用率上下限分别为89.03%和79.46%,4号高炉的喷吹煤粉利用率上下限分别为91.51%和84.14%。认为,3号高炉和4号高炉所使用喷吹煤粉来自同一系列,因此可以通过采取稳定煤粉粒度波动、优化富氧鼓风和提高入炉焦炭强度等措施,来提高喷吹煤粉利用率。

国内某高炉喷吹煤粉的性能评价

高炉喷吹煤粉的优点主要包括显著降低炼铁焦比及生产成本、有效调节高炉热制度、喷吹煤粉反应过程中提高煤气的穿透扩散能力和还原能力、缓解焦煤需求量、减少炼焦投资和环境污染等。为进一步优化高炉喷吹燃料结构和降低炼铁成本,文章对国内某高炉喷吹使用的煤粉的煤质特性进行了深入研究。结果表明:1#煤为烟煤,固定碳含量低、挥发分高,氢元素含量在所试验煤粉中最高,灰分中的CaO和MgO的含量之和最高,超过24%;其他煤种为无烟煤;4#煤的可磨性指数低于40;需要控制其在混煤中的配比。

酒钢7#高炉96h休风炉况快速恢复实践

阐述了酒钢本部7#高炉96h休风前炉况、检修准备、检修过程控制和高炉送风后炉况恢复,归纳检修过程及炉况恢复过程中存在的问题,为后续高炉长期检修炉况顺利恢复提出指导意见.

高炉富氧鼓风技术发展现状简析

高炉富氧鼓风技术取得了明显进展,如新型氧煤枪、SIP等先进高比例富氧技术的推广应用,而面临的难题主要是,高比例富氧后,高炉呈现“上冷下热”和边沿气流发展等状况,影响高炉稳定顺行。2020年,新疆八钢开启氧气高炉冶炼实践,第一阶段实现35%高富氧冶炼目标,第二阶段试验将引入欧冶炉CO_(2)脱除后的煤气,打通煤气循环的工艺流程,实现50%的超高富氧技术突破。展望未来,高炉发展方向是富氧率、喷煤量不断提高,并逐渐步人高富氧大喷煤的背景中,最终走向全氧高炉冶炼。

生物质重整煤气喷吹-氧气高炉的低碳潜力分析

我国钢铁行业以高炉-转炉长流程为主,一次能源消耗主要为煤粉与焦炭,化石能源消耗大、碳排放高,其中70%的CO_(2)排放集中在高炉炼铁工序。双碳背景下,亟需研发低碳炼铁技术以降低高炉工艺的能源消耗和CO_(2)排放。提出一种生物质重整煤气喷吹-氧气高炉(BRGI-OBF)工艺流程,该工艺通过优化气化炉工艺参数与生物质替代煤粉重整,产生的重整煤气满足高炉的富氢冶炼需求,并降低了化石能源的使用。结合高炉煤气富氧燃烧碳捕集,可实现末流烟气中CO_(2)富集,从而实现高炉低能耗与低碳(负碳)排放。为分析BRGI-OBF工艺的低碳潜力,首先运用Aspen Plus搭建了BRGI-OBF工艺模型,研究了气化炉输入热量与生物质种类对工艺性能的影响。基于计算得到的工艺参数,运用高炉炼铁工艺能耗计算方法,对比分析了传统高炉工艺与炉顶煤气循环-氧气高炉(TGR-OBF)工艺的能耗与碳流情况。结果表明,向气化炉提供适宜的热量可有效减少煤粉用量,同时增加循环煤气量,最多可减少煤粉用量124.2 kg/t(以生铁计);生物质种类对生物质用量与重整煤气的组分产生显著影响,采用杨木半焦进行重整时,杨木半焦用量为204 kg/t,重整煤气中H_(2)体积分数达29.91%,满足富氢冶炼需求。此外,BRGI-OBF工艺显著改善了能源结构,其化石能源占比约55%,与传统高炉相比,降低煤粉消耗17.6%、焦炭消耗29.3%。该工艺流程耦合富氧燃烧碳捕集技术后,末流中存在碳素372.6 kg/t,以易于压缩捕集的高浓度CO_(2)(>90%)形式存在。扣除由杨木半焦造成的碳素排放,总碳素排放为-109.9 kg/t,相当于生产每吨铁水可额外捕集CO_(2)403 kg,可实现生物质+CCS的负碳技术,为钢铁行业实现深度脱碳提供重要支持。

高富氧喷吹条件下钒钛炉料的软熔性能

高炉炼铁工艺是钢铁冶金中能源消耗量最高的流程之一。在国家“降碳减碳”政策的号召下,保证高炉稳定顺行是节能减排的重要前提。高炉软熔带的位置、形状对炉内煤气流的分布状态及高炉的稳定顺行具有重要影响。本文通过模拟高富氧喷吹条件下高炉的还原性气氛,在不同还原性气氛条件下采用高温熔滴炉进行钒钛炉料的软化熔滴试验。结果表明:随着富氧率的提高,煤气中CO的体积分数增加,钒钛炉料的软化开始温度和软化结束温度均降低,软化温度区间变大;当CO体积分数从30%增加到45%时,软化开始温度下降72℃,软化结束温度下降43℃,软化温度区间扩大29℃。富氧喷吹后,熔化开始温度升高,炉渣流动性变好,滴落物质量增加;富氧喷吹后,钒钛炉料的软熔带整体呈现“上移扩大”的趋势,软熔带的最高压差逐渐降低,透气性得到改善,Ti元素向渣中迁移增强,Fe元素向渣中迁移得到抑制。

烟煤特性及其对喷吹安全性的影响研究

烟煤挥发分高、易燃易爆的特性使得烟煤用于高炉喷吹时受到较大限制。文章选取了山西建龙高炉喷吹的四种烟煤,分析了四种烟煤燃烧特性参数、爆炸性和可磨指数等,研究了烟煤粒度和比例对喷吹安全性的影响。研究结果表明,混煤中烟煤比例逐渐提升,混煤的着火点逐渐降低,爆炸性逐渐增强;增大烟煤煤粉的粒度能够有效减弱烟煤的爆炸性,是保证烟煤喷吹安全性的有效方法;国华能源烟煤和内蒙江化烟煤配比高于80%时,应合理控制煤粉的制粉、储运和喷吹系统的温度和氧含量以保障生产安全。

喷吹神东高钙烟煤对高炉回旋区热状态的影响

高炉风口和回旋区的热状态对炉内煤气流的一次分布具有重要影响,进而影响高炉的经济技术指标。为探究喷吹神东高钙烟煤对高炉回旋区热状态的影响,本文通过收集某钢铁企业试烧期间高炉鼓风参数及其他各项操作参数,采用Fluent仿真模拟方法,建立风口回旋区的三维燃烧模型,系统分析不同喷吹条件下温度分布、气体分布、速度分布的变化规律,从而确定在风口复杂条件下喷吹神东高钙烟煤对高炉回旋区热状态的影响。模拟计算结果表明:神东高钙烟煤和ES无烟煤燃烧后产生的还原气体量最多,生产时有利于矿石的还原;向高炉喷吹神东高钙烟煤、HX烟煤、WN烟煤、SG烟煤与ES无烟煤混合煤粉时,燃尽率分别为72.25%、70.11%、68.87%、67.56%,神东高钙烟煤与ES无烟煤混合喷吹时煤粉的燃尽率最高,这是由于神东高钙烟煤和ES无烟煤的CaO质量分数较高,其在风口、回旋区内的燃烧特性最佳;混合喷吹神东高钙烟煤与ES无烟煤时,风口、回旋区内的煤气成分和煤粉燃尽率等方面要强于其他三种情况,适宜向高炉喷吹。

试论高炉燃料替代的降碳路径

为有效降低高炉工序的CO_(2)排放量,向高炉喷吹气体、液体或固体燃料来替代焦炭受到广泛的关注。以我国6家典型钢铁企业7座1800m^(3)级高炉2021年的主要技术经济指标为基础,重点分析了燃料比和煤比对高炉CO_(2)排放量的作用和影响。结果表明,6家典型钢铁企业高炉CO_(2)排放量约为1.419~1.595Vt,影响高炉CO_(2)排放量相关性最强的因素且最重要的指标是燃料比,而单纯提高喷煤比的技术手段并不是降低高炉CO_(2)排放量的决定性因素。因此,通过优化喷吹燃料的种类,以氢代碳,实现有效替代,才是降低高炉CO_(2)排放量的有效途径。

高炉煤气锅炉富氧燃烧特性及运行优化研究

为有效提高高炉煤气锅炉热效率,以某钢铁企业496t/h高炉煤气锅炉为研究对象,采用EBSILON数值模拟软件对不同工况、不同富氧情况下的高炉煤气锅炉系统进行模拟.结果表明:氧气体积分数为35%时,3个工况的锅炉热效率与普通空气助燃相比分别提高了139%、124%、124%;绝热燃烧温度分别提高了174K、175K、177K;优化出3个工况下风机的最佳运行方案,3个工况下风机每年可节约的电费分别为10257446万元、6876715万元、3265479万元,每年燃料可节约的费用分别为1218735万元、971649万元、757953万元,具有良好的经济性;每年可减少的二氧化碳排放量分别为10164×10^(7)m^(3)、8106×10^(6)m^(3)、6321×10^(6)m^(3),具有良好的减排效果;实施富氧燃烧技术有利于减少NO_(x)的排放,降低脱硝成本.

首钢股份3号高炉高富氧冶炼实践

对首钢股份3号高炉高富氧冶炼实践进行了总结。3号高炉富氧率由4.74%逐步提高到6.73%,对理论燃烧温度、炉腹煤气量、煤气流分布、煤气利用率等参数的影响较大。为此,操作上进行了相应调整,通过采取管控原燃料质量、调整装料制度、优化送风制度、调控热制度及改善出铁操作等措施,理论燃烧温度维持在2100℃左右,炉腹煤气量指数控制在60.5~62.5m/min,煤气利用率提高至50.7%左右。3号高炉主要技术经济指标稳步改善,利用系数最高达到2.54V(m^(3)·d),焦比降至320kg/t。

高炉风口氢煤共喷的数值模拟研究

氢气是一种无碳的清洁能源,具有良好的还原性,可替代部分高炉喷吹煤粉。向风口喷注氢气可以降低煤比,减少高炉碳排放。基于数值模拟方法,建立高炉风口喷氢的三维稳态模型,研究喷注不同含量的氢气与氧气对煤粉燃烧和回旋区状态特性的影响。模拟结果表明,氢气燃烧产生的热量可以促进煤粉脱挥发,但氢气燃烧会消耗大量氧气,降低挥发分周围的氧气浓度,影响挥发分的燃烧效率。当高炉注氢时,氧气消耗速率加快,CO_(2)产生量明显下降,H_(2)、水蒸气生成量增加,但CO含量从42.5%下降至38.7%,煤粉燃尽率从69.8%降低至66.4%。当富氧率增加2%时,风口出口平均温度提高22 K,煤粉燃尽率上升2.3%,CO产生量由38.7%提高到40.0%。研究成果可为高炉氢煤共喷操作提供理论指导和数据支持。

高炉风口喷吹煤粉的燃烧模拟研究

为了减少高炉炼铁过程的焦比,现代高炉通过风口喷吹煤粉代替部分焦炭。以某高炉的设计参数与生产数据为模拟条件,建立高炉风口回旋区喷吹煤粉燃烧的三维模型,对直吹管、煤粉喷枪、风口、回旋区、焦炭床等高炉下部区域的煤粉燃烧现象进行模拟研究,并结合该高炉提供的生产数据验证模型的可靠性。模拟结果显示,热风离开风口进入回旋区,最大速度达到257m/s,之后不断减小。煤粉进入高炉后,挥发分在回旋区内距离风口截面0.4m处开始析出,在回旋区内距离煤粉喷枪1m处形成2600K的高温区域。部分粒径大于70μm的煤粉在回旋区内未完全燃烧,就进入焦炭床并沿炉缸中心向上运动,燃尽率过低,影响高炉透气性。