Influence of conveyance methods for pulverised coal injection in a blast furnace

Pulverised coal injection (PCI) is a widely adopted industry practice for reducing blast furnace coke rates. The conditions under which pulverised coal (PC) is injected and combusted, including the co-injection of natural gas (NG), can lead to complex combustion phenomena inside the blast furnace, which must be understood to provide improved furnace performance. This research examines computational simulations of the co-injection phenomena, as well as the industrial drivers behind the project. A wide-ranging parametric study was conducted utilising numerous variations in furnace operating conditions, as well as a new technique for the conveyance of PC. It was found that utilising NG as the carrier gas for PCI could increase coal burnout across the raceway region from about 71% to approximately 87% without altering the design of the tuyere/blowpipe region, with an increase to 96% possible if a shift to a dual lance design for NG injection is considered.     

国外高炉喷煤状况述评

近年来，国外高炉喷煤技术有效的进展，主要表现在：喷吹煤种多样化，重视制粉工艺的选择，喷吹工艺以浓相输送为主要特征，高炉采用富氧和低焦比操作。     

Value-in-use of biocarbon fuel for direct injection in blast furnace ironmaking

Substitution of pulverised coal injection (PCI) by solid biocarbon fuel has the potential to achieve substantial reduction in GHG emissions associated with blast furnace ironmaking. A systematic evaluation was conducted on the performance of solid biocarbons produced from a single raw biomass source using different pyrolysis technologies. A techno-economic model was developed to evaluate the value-in-use (VIU) of the prepared solid biocarbon in blast furnace ironmaking. The VIU of solid biocarbon is strongly influent by its O/C (oxygen to carbon) mass ratio which is determined by the pyrolysis technology and conditions employed. It also dictates the cost of raw materials required to support the blast furnace ironmaking process and the potential GHG emissions achievable. In order to balance all factors that may affect the VIU of solid biocarbon, close collaboration between steelmakers and solid biocarbon producers is critical for producing suitable solid biocarbon fuel to replace PCI.     

宝钢高炉高煤比的实践与探索

宝钢高炉自1992年喷煤以来，从优化喷吹煤种、控制混合煤成分、改善喷煤设备性能和操作参数、制订原燃料质量标准和重新设计高炉操作制度等方面着手，通过多年的科学探索和生产实践，从1998年6月份起，高炉喷煤比已连续5年多的时间稳定在200kg／t的水平，最高曾达到260kg／t，并且高煤比是在高产能、低燃料消耗下取得的。     

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 in-dicated that additives significantly affected the melting property of coal ash in high temperature zone.Al-though the unburnt char, raw coal ash, and catalyzed coal ash failed to wet the coke surface, the wettabil-ity 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 reac-tivity.Thereinto, the coal ash containing Fe2 O3 exhibited a larger influence on the reactivity than that containing CaO.     

Numerical simulation on novel blast furnace operation of combining coke oven gas injection with hot burden charging

A novel blast furnace operation of coke oven gas (COG) injection simultaneously with hot burden charging has been proposed to solve the problem of insufficient heat in the BF shaft zone under the condition of COG injection and make full use of the abundant sensible heat of high temperature burden. In this paper, the novel process has been simulated with a multifluid blast furnace model. The results show that, in comparison with the operation of COG injection only, under the operation of COG injection together with hot burden charging, the temperature in the upper zone of the shaft increases while that in lower zone decreases. Furthermore, the reduction of iron bearing material is improved in the top zone, and the cohesive zone tends to descend and narrow. The coke ratio, fuel ratio and CO₂ emissions of the operation of charging hot pellet and coke with the temperature of 800°C are decreased by 4.0, 4.7 and 5.3% respectively, while the hot metal productivity is increased by 7.14%. Therefore, COG injection combined with hot burden charging operation not only increases temperature in the upper part of the blast furnace but also decreases energy consumption per tonne hot metal.     

Mathematical simulation and experimental study on coke oven gas injection aimed to low carbon blast furnace ironmaking

Coke oven gas (COG) tuyere injection is recognised as one of effective measures to achieve low carbon blast furnace ironmaking. In this paper, simulation of blast furnace operation with COG injection was investigated by means of multi-fluid blast furnace model, and the softening-melting and dripping behaviours of mixed burden were studied on basis of simulation results. The model simulation shows that, with COG injection rate increasing, the concentration of inner-furnace hydrogen is enhanced obviously. Cohesive zone moves downwards and becomes thinner. The column permeability gets better. Hot metal productivity increases and CO₂ emission reduces. Compared with conventional operation without COG injection, when COG injection rate is 152.34?Nm³/tHM, column pressure drop is decreased by 31.5% and hot metal productivity is increased by 26.36% and CO₂ emission is decreased by 17.54%. Therefore, the simulation and experimental results reveal that it is achievable to improve blast furnace operation performance, such as hydrogen-enriched reduction, better column permeability, high efficiency, low carbon emission and so on.     

13m^3高炉喷吹粒煤工业试验研究

１３ｍ＾３小高炉喷吹粒煤（－２ｍｍ）试验目的是考察小高炉喷吹粒煤的可行性及其工艺技术特点。在无富氧和较低风温条件下，喷吹粒煤３３～５６ｋｇ／ｔ，置换比达０．７３～０．６６，取得了与喷吹粉煤相近的效果。喷粒煤期间炉缸活跃，产量提高，炉况顺行，质量改善。     

宝钢4号高炉钛矿护炉期间的高煤比生产实践

为了控制炉缸侧壁温度,宝钢4号高炉采取了限产、堵风口、添加钛矿冶炼护炉等维护措施,以确保高炉长寿。在添加钛矿护炉时,生成的高熔点钛的碳氮化合物导致炉渣黏度大,恶化高炉的透气性,影响各项经济技术指标的提升。宝钢4号高炉在维持入炉钛为10 kg/t的生产条件下,通过采取保证中心、控制边缘的气流模式调整煤气流分布,优化配料降低渣比改善高炉透气性,增加鼓风温度降低湿分促进煤粉燃烧等措施,保持煤比在180 kg/t以上的水平。     

燃烧效果最佳的混煤喷吹配比计算方法

在归纳和比较常用高炉喷吹配煤方法的基础上,以计算法配煤的思想为指导,提出了以实现最佳燃烧效果为目标的混煤模型.通过曲线拟合得到混煤着火点随高挥发分煤种配比增大而减小的关系曲线,混煤着火点下降速率减小到某一较小值时的混煤比例即为该煤种组合燃烧效果最佳的比例.应用该方法对四组不同煤种组合混煤进行配比优化,经静态燃烧性实验证明,该计算法所得结果准确可靠,有一定实用性.     

高炉喷吹用煤的可磨性研究

在对高炉喷吹用煤和兰炭进行工业分析的基础上,对不同比例兰炭与煤混合试样的可磨性分别进行了测试分析。结果表明,试验用煤和兰炭的水分含量均高于喷吹用煤指标要求,可磨性指数普遍偏低,其中高挥发分烟煤的可磨性最低,不符合喷吹用煤要求。     

大喷煤条件下鞍钢高炉喷吹煤粉的炉内利用率

为了探究目前大喷煤条件下煤粉喷入高炉后在炉内的利用情况,对鞍钢高炉除尘灰进行收集、取样和测试;同时采用岩相分析手段观察分析高炉炉尘中未燃煤粉、焦炭和矿物质灰渣的组成及微观形貌,定量计算出除尘灰中不同含碳物质的质量分数。结果表明,整体来看,鞍钢4座3 200 m³级别的大高炉喷吹煤粉在炉内的利用率要低于其余4座小高炉,说明高炉在提高煤比的同时,还需重点关注煤粉的燃尽率。通过调节各项操作参数来提高煤粉在高炉内的利用率,可节约生产成本并保证高炉的顺行稳产。     

高炉喷吹贫瘦煤最低着火温度

从工业安全角度出发,对实验煤样进行了元素分析和工业分析,在高德伯儿格-格瑞瓦尔德炉中对潞安常村、漳村贫瘦煤的最低着火温度进行了比较全面、系统的实验研究,探讨了煤粉质量浓度、喷吹压力以及粒度对最低着火点的影响.结果表明,最低着火温度随煤粉质量浓度的减小而升高,随喷吹压力和煤粉粒度的增大而升高.对实验数据进行线性回归分析,得出影响因素与最低着火温度的函数关系,从而为贫瘦煤工业应用的安全性提供了一定的参考依据.     

韶钢高炉喷煤技术的进步

韶钢高炉通过对现有喷煤系统的技术改造，主要是新建室内贮煤场、采用皮带机输送煤、增大磨煤制粉能力、采用大喷吹罐喷吹、实现喷吹PLC自动控制发展喷煤技术和优化生产管理等措施，煤比连续8个月达到153kg/t，入炉焦比下降到390kg/t。     

富氧喷煤技术在韶钢300 m3级高炉的应用

介绍富氧喷煤技术在韶钢300 m3级高炉的应用及其效果.     

鞍钢高炉喷煤流量调控技术研究

介绍了鞍钢高炉喷吹煤流量调节控制技术的研究过程，装置构成，工作原理及工业试验的结果，高炉喷吹煤粉总体流量调节控制系统由传感器，大口径电容噪声式流变送器，大能力可调量给煤器及ＳＴＤ总线工业计算机所成。试验结果表明，该项技术是实现稳定均匀喷吹的重要措施。