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.

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.

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.

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.

Gas-Particle Flow and Combustion Characteristics of Pulverized Coal Injection in Blast Furnace Raceway

The two-dimensional steady-state discrete phase mathematical model is developed to analyze gas-particle flow and combustion characteristics of coal particles, as well as components concentration and temperature distribu- tion of coal gas in the process of pulverized coal injection of blast furnace raceway. The results show that a great deal of coal gas discharges on the top of raceway away from the tuyere, and the residence time of coal particles in the re- gion of blowpipe and tuyere is 20 ms or so and 50 ms when it reaches raceway boundary. The pressure is the highest at the bottom of raceway and the maximal temperature is about 2 423 K. The char combustion is mainly carried out in the raceway and the maximum of char burn-out rate attains 3× 10-4 kg/s.

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.

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.

Properties and Structural Optimization of Pulverized Coal for Blast Furnace Injection

The properties of mixed coals were studied on the basis of known various properties of the injecting coals in the treatise.The structure of the injecting coals was optimized and put into practical application.It was found that the ignition point was lowered with mixed coals,however,both combustibility and grindability were improved,and explosibility of the mixed coals were decreased as well.Hence,mixed coals injection not only can improve the amount of the injecting coals greatly,but also improve the economical and technical indexes of the blast furnace.

Interaction mechanism between coal combustion products and coke in raceway of blast furnaces

The interaction mechanism between the combustion products of pulverized coal injected and coke in the raceway of blast furnace was studied through thermodynamic calculation and experiments.The results indicated that additives significantly affected the melting property of coal ash in high temperature zone.Although the unburnt char,raw coal ash,and catalyzed coal ash failed to wet the coke surface,the wettability of the catalyzed coal ash on the coke was greater than that of the raw coal ash.Since the unburnt char had weak reaction with the coke surface,it showed little influence on the surface morphology of the coke.The interaction between the raw coal ash and the coke gave rise to the increase in the pore size on the coke surface.However,the raw coal ash only affected the coke surface and the entrances of the pores owing to its poor fluidity.After being melted,the catalyzed coal ash was expected to immerge into the inside part of the coke and then react with the coke,resulting in an expansion and increase of coke cavities.The raw coal ash and the unburnt char reduced the coke reactivity,while the catalyzed coal ash improved the coke reactivity.Thereinto,the coal ash containing Fe2O3 exhibited a larger influence on the reactivity than that containing CaO.

Development of a Fuel-flexible Co-gasification Technology

As one of promising clean coal technologies used to reduce pollutant emission and CO2 discharge, cogasification has been extensively investigated. In this paper, a new co-gasification technology using coal and natural gas was developed. The distinct advantages of this technology are the excellent fuel flexibility and the availability to establish the gasifler by reconstructing the blast furnace or similar shaft furnace. Based on the concept of the new co-gasification technology, lab-scale experiments and modeling study were carried out. The obtained results indicate that gasification is undertaken at ideal thermodynamic environment where quasi-equilibrium could be reached without catalysts. The modeling results are in agreement with experimental data, demonstrating the validity of the model and that Aspen Plus is a useful tool for the analysis of the co-gasification process. Furthermore,the effect of major operation parameters, including oxygen flow rate and steam flow rate, on co-gasification process was investigated using the developed model.

Comparison of semi-coke with traditional pulverized coal injection and iron ore sintering fuels based on chemical structure and combustion behavior

Substantial semi-coke has been produced through the industrialized low-temperature pyrolysis process,which has great potential as an alternative fuel for pulverized coal injection(PCI)and iron ore sintering.X-ray diffraction,Raman spectroscope,and thermal analysis were used to compare the carbon chemical structure and combustion reactivity of semi-coke,pulverized coal,and coke breeze.The results show that the average volatile matter content in 46 types of semi-cokes is 8.94 wt.%.The fluctuation range of the characteristic parameters of the semi-coke chemical structure is d_(002)=(0.352–0.379)nm and A_(D1)/A_(G)=(2.51–7.92),while the fluctuation range of the characteristic parameters of pulverized coal is d_(002)=(0.348–0.373)nm and A_(D1)/A_(G)=(1.71–9.03)(where d_(002)means the interlayer spacing between the aromatic planes,and A_(D1)/A_(G)is an index that characterizes the degree of disorder of the char structure through the area ratio of the defect peak band D1 to the perfect graphite peak band G);the overlap between these ranges is relatively high.Contrarily,the fluctuation range of the characteristic parameters of coke breeze is d_(002)=(0.343–0.350)nm and A_(D1)/A_(G)=(0.75–2.51),which is markedly different from that of semi-coke.Semi-coke combustion reactivity is close to that of pulverized coal,but considerably better than that of coke breeze.In terms of chemical structure and combustion reactivity,semi-coke can be used as an alternative fuel for PCI;however,when used for sintering alternative fuel,matching of the heat supply and demand in the later sintering stage must be scrupulously analyzed.

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。

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。

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。

高炉新建兰炭制粉系统的工艺设计

某钢厂新增一套全兰炭的磨煤制粉系统,以满足高炉喷煤需求。在借鉴现有成熟的中速磨负压工艺技术的同时,充分考虑兰炭水分高、磨损性等问题,采用不设煤粉缓冲仓工艺技术,对设计方案进行优化与改进。实践应用表明,该方案运行可靠、稳定,对后续类似的高炉喷煤系统进行新增制粉能力项目改造,具有一定的参考意义。

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。

新田煤矿选煤厂无烟煤加工优质冶金烧结煤的经济效益分析

阐述了烧结用煤灰分增加对钢铁企业生产的影响,并对新田煤矿选煤厂利用现有选煤工艺,多出优质烧结用煤的经济效益进行了分析,提出多出烧结煤有利于无烟煤资源的更合理利用,同时可提高企业的经济效益。

生物质炭煤粉高炉混合喷吹性能分析

探究生物质炭煤粉高炉混合喷吹技术的可行性和优势,重点对该混合喷吹性能进行分析,并提出针对性的改进方案。基于实验测试和数值模拟,分析了生物质炭煤粉混合喷吹的燃烧特性、热力学性能及其对高炉煤气温度、煤耗和污染物排放的影响。实验结果表明,生物质碳作为煤粉的替代燃料,在高炉混合喷吹中能够稳定燃烧,为增加高炉炉料提供了新的思路;数值模拟结果显示,生物质炭煤粉的混合喷吹可以显著提高高炉的燃烧效率,降低煤耗和二氧化碳排放量。此外,对生物质炭煤粉混合喷吹技术的经济性和环境效益进行了初步评估,结果表明,该技术在高炉冶金行业具有广泛的应用前景。