Combustion performance of pulverized coal and corresponding kinetics study after adding the additives of Fe_(2)O_(3) and CaO

Combustion performance of pulverized coal(PC)in blast furnace(BF)process is regarded as a criteria parameter to assess the prop-er injection dosage of PC.In this paper,effects of two kinds of additives,Fe_(2)O_(3) and CaO,on PC combustion were studied using the thermo-gravimetric method.The results demonstrate that both the Fe_(2)O_(3) and CaO can promote combustion performance index of PC including igni-tion index(C_(i)),burnout index(D_(b)),as well as comprehensive combustibility index(S_(n)).The S_(n) increases from 1.37×10^(−6) to 2.16×10^(−6)%2·min^(−2)·℃^(−3) as the Fe_(2)O_(3) proportion increases from 0 to 5.0wt%.Additionally,the combustion kinetics of PC was clarified using the Coats-Redfern method.The results show that the activation energy(E)of PC combustion decreases after adding the above additives.For instance,the E decreases from 56.54 to 35.75 kJ/mol when the Fe_(2)O_(3) proportion increases from 0 to 5.0wt%,which supports the improved combustion per-formance.Moreover,it is uneconomic to utilize pure Fe_(2)O_(3) and CaO in production.Based on economy analysis,we selected the iron-bearing dust(IBD)which contains much Fe_(2)O_(3) and CaO component to investigate,and got the same effects.Therefore,the IBD is a potential option for catalytic PC combustion in BF process.

Numerical simulation of the effect of coaxial and cross-axis injection modes on pulverized coal combustion in the raceway of blast furnace tuyere

The aim of this study is to investigate the influence of the angle of the pulverized coal (PC) injection lance on the combustion characteristics of fuel in the raceway of blast furnace tuyeres. Using FLUENT software, a Euler-Lagrange three-dimensional numerical model was constructed to analyze the influence of different positions of blast furnace tuyere coal powder injection lance (coaxial and cross-axis) on key parameters such as temperature distribution, gas flow, and combustion efficiency. The results demonstrate that adjusting the angle of the injection lance significantly modifies the average and peak temperatures in the raceway, while the composition of gas components remains relatively stable. When the injection lance angle is 10°, the average temperature and peak temperature in the raceway are 2294 K and 2747 K, respectively. When the injection lance angle is 12°, the combustion efficiency of the PC reaches 80.8%. This study reveals the significant impact of the injection lance angle on the combustion process. Especially at an angle of 12°, the combustion efficiency of the blast furnace significantly improves. With coaxial injection, the combustion rate increases as the distance between the injection lance tip and the tuyere increases. This paper is instructive for the optimization of the blast furnace combustion system, which improve fuel utilization efficiency and reduce environmental emissions. This paper provides practical recommendations for adjusting blast furnace operational parameters, offering insights for achieving more efficient and environmentally friendly industrial production.

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.

Pulverized Coal Combustion of Nitrogen Free Blast Furnace

The efficiency of coal combustion is an important factor for the blast furnace process.The influence of low xO/xC on coal combustion performance under nitrogen free blast furnace condition was researched through the self-developed pulverized coal burning device.The results show that the coal combustion rate reduces with xO/xC decreasing,and the combustion rate of bituminous coal is higher than that of anthracite.The coal combustion rate ascends with the rise of volatile matter,but when volatile matter of pulverized coal is more than 18%,the combustion rates will not increase correspondingly.Small amount of CaCO3 and CO2 additions can promote coal combustion,and the effect of CaCO3 is more apparent,which can increase the pulverized coal combustion rate by 15%-18% or so.

Kinetic study on co-combustion of pulverized anthracite and bituminite for blast furnace injection

Combustion behavior of single pulverized coals(PCs)and co-combustion characteristics of anthracite(AT)and bituminite(BT)blends with 20 wt.%volatile were studied by thermogravimetric experiments.The results indicated that reaction characteristics of PCs were closely related to their functional group structure and consequently,the pyrolysis of PCs with highly active functional groups initiated at lower temperatures.It was also noticed that the discrepancy of functional group structures between AT and BT might impair their interaction during combustion.The early exhaust of BT at low temperatures would possibly lead to an independent combustion of volatile and residual carbon and eventually the inefficient combustion of their blend.However,the mixing of AT and BT with similar functional group structures was more likely to achieve blends with superior combustion property.Simultaneously,non-isothermal kinetic analysis mani-fested that the combustion of blends followed random pore model(RPM),and therefore,the parameters calculated by RPM were more accurate to describe their combustion behavior.The kinetic calculation results showed that the activation energy required for decomposition of blends in early combustion stage was much lower owing to the excellent activity of volatile,while residual carbon with stable aromatic hydrocarbon demanded more energy to initiate its combustion.

高炉喷吹煤粉预热工艺技术进展及应用

煤粉预热可提高高炉喷吹煤粉的初始温度,加强煤粉在风口前的气化热解过程,降低喷煤对风口区域热风的冷却效应,进而提高煤粉燃烧率,为高煤比创造条件。对现有几种煤粉预热工艺,如高炉废烟气对流预热、电磁感应预热、立式筒仓管板预热和流化床预热技术特点依次进行了分析。高炉废烟气对流预热工艺,充分利用高炉煤气和热风炉废烟气余热,既能提高煤粉初始温度,又能减少能源浪费。攀钢钒高炉和舞钢高炉预热煤粉工业试验结果表明,提高煤比和降低焦比的效果良好,应用前景广阔。

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。

基于煤质特性的京唐高炉喷吹煤结构优化

为优化首钢京唐高炉喷吹煤结构和降低冶炼成本,对京唐高炉喷吹煤粉的煤质特性进行了分析,用煤焦置换比理论公式计算了单种煤的理论置换比,并计算了京唐高炉喷吹煤的煤粉利用率。认为,随着高炉煤比的提高,煤焦置换比逐步降低;通过对配煤结构及高炉操作参数进行优化,京唐三座高炉的煤粉利用率得到进一步提升。1号高炉煤粉利用率达到了97.64%,2号高炉达到了97.58%,3号高炉达到了98.14%,较2022年6月分别提高了3%左右。

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。

Improvements on Calculation Model of Theoretical Combustion Temperature in a Blast Furnace

On the basis of the existing originally modified calculation models of theoretical combustion temperature（TCT）,some factors,such as the combustion ratio of pulverized coal injection（PCI）,the decomposition heat of PCI and the heat consumption of SiO2 in ash reduced in high temperature environment,were amended and improved to put forward a more comprehensive model for calculating TCT.The influences of each improvement on TCT were studied and the results were analyzed compared with those of traditional model and originally modified model,which showed that the present model could reflect the thermal state of a hearth more effectively.

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。

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。

提升制粉系统产能的技术优化及改造实践

2022年9月16日以前,重钢炼铁厂只有三套煤粉制备系统,总制粉能力为180 t/h。2020年底,重钢在完成所有高炉大修后恢复四座高炉满负荷生产,总的煤粉需求量达到了210 t/h,当时的制粉能力已无法匹配高炉煤粉需求。同期,由于焦炭资源紧张且成本较高,提高制粉能力满足高炉煤粉需求已成为当时提高喷煤比、缓解焦炭资源紧张及降低炼铁成本的重要途径。本文主要以重庆钢铁炼铁厂的煤粉制备系统现状为例,介绍了如何通过技术优化及设备改造来提升煤粉制备系统制粉能力满足高炉所需煤粉量。文中从原材料质量提升、设备工况改进、生产操作优化等多方面详细阐述了多项举措,为同行在如何解决制粉能力不足、提升制粉系统制粉量、保障高炉煤粉稳定供应提供了指导性思路。

核桃壳炭与煤粉混合燃烧特性及协同作用研究

在“双碳”目标积极推进背景下,节能减排已经成为当前钢铁工业绿色低碳发展的首要目标。生物质作为可再生碳源,应用于高炉冶炼可有效降低高炉冶炼过程的CO_(2)排放。本文选取农业生物质核桃壳为原料,深入研究高温条件下煤粉和核桃壳炭的热化学行为,研究不同比例混合燃料的燃烧特性,探讨煤粉与核桃壳炭共燃的协同作用,确定最优混合比例范围。结果表明,核桃壳炭的加入可以改善高炉喷吹煤粉的燃烧性能,核桃壳炭与煤粉的最佳掺混比例为25%,此时混合燃料的综合燃烧性能指数为6.253×10^(-10)(min^(-1)·℃^(-3));可燃性指数为3.715×10^(-6)(min^(-1)·℃^(-2))。核桃壳炭的掺入,有利于高炉生产实现节能减排,推动废弃物资源化处理和钢铁行业绿色低碳发展。

燃烧优化技术在热电中储式煤粉炉上的应用

当前的化工产品生产对化工企业锅炉的蒸汽质量,相应速度、锅炉效率提出了更高的要求,同时工况多变和煤质多变等因素影响原有控制系统(DCS)依靠经验进行人工操作的控制模式,难以满足生产的需要。基于此,针对唐山三友公司热力中心#5480 t/h中储式煤粉炉生产实际现状,采用燃烧优化技术(BCS),实现锅炉运行的自动控制,尤其是在当前机组负荷及煤质变动较大的情况下,可以大大减轻操作人员的劳动强度,促进生产质量提升。

富氧率提升下的钒钛矿高炉冶炼

对承德钒钛某2500 m3高炉提高富氧率的生产实践进行了总结,系统地分析了富氧率提高对钒钛矿高炉冶炼生产的影响。高炉提富氧后,在相同的w[Si+Ti]条件下,理论燃烧温度有所提高,降低w[Si+Ti]仍能保证铁水有充足的物理热;通过合理配煤,炉况更容易稳定,在铁水温度不变的前提下,更适合于低w[Si+Ti]冶炼。根据研究结果,从高炉工艺操作制度、理论燃烧温度控制、高富氧条件下生产组织优化以及提高富氧对炉缸活跃程度的影响等方面入手,研究了钒钛矿冶炼高炉长期保持高富氧率的工艺操作方法。通过对装料制度、送风制度以及喷煤工艺的优化调整以及加强炉前管理等一系列措施,实现了钒钛矿高炉冶炼在高富氧条件下的长周期稳定生产,钒回收率与以往相比显著提高。

高炉操作的工艺优化与效率提升方法研究

对比分析传统高炉工艺和经过技术优化的新工艺,将高炉操作分为控制组(传统工艺)和实验组(引入新技术)。传统高炉工艺存在能源效率低、废品率高、硫排放和烟尘排放问题,缺乏高效的燃烧控制和智能系统;新技术包括高效燃烧系统、智能控制系统和环保技术等。对比结果表明:在能源方面,新技术使能源效率提高15.2%,生铁含铁量提高2.61%,废品率降低1.5%;废气处理方面,新技术使硫排放减少85.2%,烟尘排放降低41%;废渣处理方面,渣滓再利用率达到76.3%。新技术的引进不仅有助于提高生产效益,降低生产成本,还使高炉操作更加可持续、环保且具有竞争力。

300MW煤粉/高炉煤气混燃锅炉燃烧特性数值模拟

钢厂高炉煤气是一种低热值燃料,它和煤粉在炉内掺烧是其一种有效的利用途径。但煤粉掺烧高炉煤气后燃烧特性与纯煤粉燃烧有很大不同,掺烧过程中易发生过/再热器超温、飞灰含碳量过高等问题,导致其在大型锅炉上的应用很少。针对某钢厂300MW四角切圆煤粉/高炉煤气混燃锅炉,使用二混合分数法对其燃烧特性进行数值模拟。对比研究了纯燃煤工况和高炉煤气掺烧量分别为10%、20%、30%的工况,发现掺烧高炉煤气时炉内温度水平有明显下降(如,掺烧10%高炉煤气时截面最高温度降低81K),且随着掺烧量的增加而加剧,但下降的趋势变缓。掺烧高炉煤气后产生烟气量增多,炉膛出口烟速有明显增加,煤粉颗粒实际停留时间缩短,使得煤粉燃尽变得困难。同时,NO的生成量随高炉煤气掺烧量的增加而明显减少。

低阶煤低温热解半焦在模拟高炉喷吹条件下的燃烧性能

采用自制固定床热解装置在隔绝空气的条件下制备神木长焰煤热解终温分别为400℃、450℃、500℃及550℃的热解半焦,利用管式沉降炉模拟高炉喷吹条件研究神木长焰煤低温热解半焦的燃烧性能,并考察了热解终温、半焦喷吹粒径以及燃烧反应温度对半焦燃烧性能的影响。研究表明：低温热解半焦的燃烧性能优于实验所选用无烟煤的燃烧性能,半焦的燃烧性能与其燃料比之间存在负相关关系,即燃料比越高,燃烧性能越差;降低热解终温、减小半焦喷吹粒径以及提高燃烧反应温度均能改善半焦的燃烧性能,当热解终温为400℃、喷吹粒径100～200目、燃烧反应温度为1100℃时半焦的燃尽度最佳为96%。本实验半焦制备及燃烧条件与现有低温热解和高炉喷吹工艺相符,且热解半焦各项性能均符合喷吹用煤指标。

无烟煤对高炉喷吹用混合煤燃烧性的影响

采用非等温热重分析法研究了5种单种煤及9种混合煤的燃烧特性,根据TG-DTG曲线得出各试验煤样的着火温度、燃尽温度、最大燃烧速率和平均燃烧速率,并进一步计算出其燃烧特性指数。探讨了不同无烟煤对高炉喷吹用混合煤燃烧性的影响,并对不同粒度区间的混合煤燃烧性进行了研究。结果表明,混合煤的燃烧性与配入单种煤的燃烧性相关,同时也受其可磨性的影响,当配入无烟煤的燃烧性能相近时,无烟煤对混合煤燃烧性的影响主要取决于无烟煤的可磨性。