炼铁过程使用木炭和生物质以及废塑料减少CO2的排放

根据实验室研究,提出了两种可应用于钢铁行业降低CO2排放的方法:利用可再生的生物质或木炭以及利用可回收的含氢废旧塑料。该方法可通过以下两个途径实现:①风口喷吹;②混入入炉炉料,例如:通过混入炼焦煤而进入焦炭,在生产用于高炉或直接还原的球团原料中添加含碳原料和塑料。为考察现代高炉风口喷吹木炭的益处,重点研究了木炭在风口回旋区的气化行为和在风口回旋区外的二次反应。采用实验室装置及其相应的检测设备,研究了几种木头在不同炭化条件下所得到的木炭的转化效率。研究结果表明,对于风口喷吹,所测试木炭的燃烧行为都不逊于矿物质煤;在模拟的高炉炉身条件下,木炭的熔损反应速率高于试验所用的矿物质煤。使用塔姆曼炉试验装置及检测仪研究了可用于直接还原和高炉的冷固结含碳、废塑料和木炭球团的还原和体积变化行为。使用该种球团可抑制和减小还原膨胀,甚至出现体积收缩。球团的自还原行为受还原气的量、气氛和操作条件的影响。采用电阻炉进一步研究了固结废塑料(聚乙烯和垃圾衍生燃料)的氧化铁的还原行为。     

鞍钢鲅鱼圈煤岩配煤技术的开发与应用

针对鞍钢鲅鱼圈所处中国东北部港口的独特地理位置特点,建立了适合鞍钢鲅鱼圈的煤岩配煤方法,分析了鞍钢鲅鱼圈配煤方案工程应用中各煤种用煤特点,考察了工程应用配煤方案的煤岩特征,并对应用煤岩配煤方案所得焦炭质量进行了分析,论述了鞍钢鲅鱼圈开展煤岩配煤技术为企业所创造的经济效益。结果显示,鞍钢鲅鱼圈通过煤岩配煤技术的研究开发与应用,使炼焦用煤结构从以肥煤为主向以进口炼焦煤为主、国产劣质炼焦煤为辅的低成本炼焦用煤结构转变,在满足大型高炉用焦质量要求的前提下,不断优化配煤方案,逐步提高焦炭质量,使焦炭的反应性从27.36%下降到24.95%,反应后强度从62.20%提高到65.37%以上。     

“三传一反”与“三环一网”——论现代高炉的再生

 “三传一反”是过程工业和过程工程的学科基础，为过程工程研究和设计的现代化提供了重要的理论保障。近年来，由于中国过程工业发展特点，导致资源和环境问题突出。为了更好地解决能源和环境问题，提出了“三传一反”与“三环一网”互补、协同的思路，希望从根本上解决过程工业出现的资源、能源和环境问题。所谓三环是指新工艺新技术符合环境(一环)要求；物质和能量实现行业内、设备内的循环(二环)；资源和能量实现全社会、跨行业、跨地区的循环(三环)利用和匹配。一网是构建煤基清洁气体能源网络，实现清洁能源自给自足，确保中国能源安全。中国能源以煤为主，直接用煤出现了能源浪费、大气污染、水污染等问题。然而煤作为不得不用的能源，只有清洁高效转化才是根本。高炉是钢铁工业的重要装备，由于近年来粗钢产能过剩、废钢循环、基建投资还本困难等问题，部分高炉面临拆除的风险，势必导致固定资产的浪费，因此如何寻找大中型高炉出路是摆在钢铁工业面前的现实问题。除了炼铁之外，高炉的能源转换和固废转化功能，还没有发挥出来。为此，提出高炉改成造气炉，利用中国资源量丰富的非焦煤型煤在高炉内气化，再利用气体净化技术，余热回收技术，实现煤的清洁转化，最终形成清洁气体能源网路。希望借助“三传一反”与“三环一网”互补理念，帮助过程工业，特别是能源工业和重工业发展。使中国钢铁工业从产量第一，向设备功能提升、装备升级、产品结构拓展等方向发展，实现产业升级、突破行业壁垒，实现过剩钢铁向煤基清洁能源的转变，助力过程工业的“弯道超车”。     

New Developments for Powder Coal Injection into the Blast Furnaces

Experiments and results concerning Powder Coal Injection into blast furnaces are presented. A pilot plant, similar to a blast furnace tuyere, with a high thermal gradient, developed at Escola de Minas‐UFOP, Brazil, is described. Several tests have been performed in this pilot plant, using a mixture of three coals and preheating the coal, giving the following conclusions: preheating of coal and the mixture of more than two coals, not commonly practised by now, are appropriate for improving the combustion rate and thus enhancing the coal injection technique.     

Shift From Coke to Coal Using Direct Reduction Method and Challenges

 Ironmaking involves the separation of iron ores. It not only represents the first step in steelmaking but also is the most capital intensive and energy intensive process in the production of steel. The main route for producing iron for steelmaking is to use the blast furnace, which uses metallurgical coke as the reductant. Concerns over the limited resources, the high cost of coking coals, and the environmental impacts of coking and sinter plants have driven steelmakers to develop alternative ironmaking processes that can use non coking coals to reduce iron ores directly. Since the efficiency and productivity of modern large capacity blast furnaces will be difficult to surpass, blast furnaces will continue to retain their predominant position as the foremost ironmaking process for some time to come. The alternative ironmaking processes are therefore expected to play an increasingly significant role in the iron and steel industry, especially in meeting the needs of small sized local and regional markets. It is likely that the importance of direct reduced iron (DRI) and hot metal as sources of virgin iron will continue to increase, especially in the developing countries where steelmaking is, and will be, primarily based on electric arc furnace (EAF) minimills. Consequently, the challenges that are faced by the new technology have to be embraced.     

Evaluation of four coals for blast furnace pulverized coal injection

 One of the effective methods to reduce coke consumption is Pulverized Coal Injection (PCI). The most important problems encountered in this method are reduced permeability, unburned and high ash content. In order to select the best coal for injection suitable tests can be used. In this investigation, experiments such as proximate and ultimate analysis, Rock- Eval and combustion tests have been performed on four kinds of coals from different mines, Sarakhs, Sangrood, Karmozd and Tabas. The results of proximate and ultimate analysis indicate that although the sulfur and ash content of selected coals are a little high, but they are suitable for coal injection. The results of combustion experiments and Rock-Eval tests show that karmozd coal is the best one to inject into the blast furnace. It is shown that mixing of coals can improve the combustion properties of pulverized coals.     

NLMK高炉喷吹煤粉优化搭配

得益于丰富的天然气资源,俄罗斯众多钢铁厂使用天然气进行高炉喷吹。为实现资源的合理配置以及效益最大化,提高高炉喷煤量、减少天然气使用成了新利佩茨克钢铁公司发展新方向。对俄罗斯所提供的两种高挥发分煤(1号、2号)和2种挥发分含量较低的煤(3号、4号)以及经配煤处理后的混煤进行工业分析和着火点、爆炸性、灰熔点等喷吹特性研究。研究发现1号和2号煤具有强爆炸性和较低的着火点,而3号和4号煤着火点较高,燃烧率较低。4种煤粉均不适于高炉单独喷吹。经混煤处理后的煤粉无爆炸性,燃烧率高于贫瘦煤,着火点介于对应2种单煤之间,灰分的质量分数均低于8%,低于国内高炉喷吹用煤对灰分要求。但俄罗斯煤的可磨性普遍较差。在所设定的混煤方案中,2号烟煤与4号贫瘦煤的混煤着火点适中、燃烧率较高、可磨性较好,较适合高炉喷吹,其中2号烟煤占40%时最适合高炉喷吹。     

粒煤喷吹控制系统在莱钢1880m^3高炉中的应用

莱钢1880m3高炉喷煤系统包括制粉与喷吹两大子系统,原煤经破碎机破碎后形成粒煤再由喷吹系统送入2座1880m3高炉,其中粒煤破碎引进德国破碎机工艺,喷吹系统引进英国克莱德工艺。该系统较之传统粉煤技术降低成本效果显著,且稳定炉况,提高生铁质量。     

Some Challenges and Opportunities in Blast Furnace Operations

Blast furnace iron making faces a lot of pressure to decrease use of metallurgical coke and carbon footprint. In many shops around the world in the meanwhile, the convectional blast furnace process is being run at near optimum efficiency for a given set of raw material conditions. Efforts are therefore being made to generate innovative ideas. Top gas recycling and nitrogen-less blowing seem to be attracting attention. Efforts are continuing for increased pulverized coal injection (PCI) to decrease coke consumption. Several furnaces experience pressure drop problems when trying to increase coal injection due to poor burden quality. The present paper attempts to analyze few of the issues related to top gas recycling in a conventional practice and those of pressure drop during PCI. Recycling of top gas even without removal of CO₂ seems to hold possibilities for enhanced PCI though with worse fuel rate. Managing layer structure and the reactivity of coke particles can be addressed in various ways to improve bed permeability.     

Influence of carbon structure and mineral association of coals on their combustion characteristics for pulverized coal injection (PCI) application

The influence of carbon structure and mineral matter of three pulverized coals on their char characteristics including reactivity was studied under a range of combustion conditions in a drop tube furnce (DTF) and thermogravimetric (TGA) furnace for PCI application. Physical and chemical properties of coals and their combustion derivatives were characterized by automated reflectogram, X-ray diffraction, scanning electron microscope, and BET N₂ adsorption. The QEMSCAN technique was used to characterize the heterogeneous nature of minerals of discrete coal particles. The TGA char reactivity was related to the proportion of coal particles displaying strong association of calcium/sulfur phases with carbon matrix to highlight the catalytic influence of minerals on char reactivity at low temperatures. The study suggested that during DTF combustion tests at 1200 °C, char reaction rates might have been catalyzed by coal minerals, particularly due to illite and its association with carbon. Under the same combustion conditions, most of the coal minerals did not transform significantly to slag phases. Coal burnout was found to improve significantly in a combustion temperature range of 1200 °C to 1500 °C. The improvement of coal burnout with temperature appeared to be influenced by coal properties, particularly as a function of the chemical nature of minerals, as well as the degree of associations with other minerals. The study implies that coals with similar mineral compositions might not necessarily reflect similar combustion behavior due to the differences in their associations with other phases. The study highlighted the significance of the characterization of the heterogeneity of coal particles including mineral associations for a comprehensive and reliable assessment of the combustion performance of PCI in an operating blast furnace. QEMSCAN is a trademark of Intellection Pty Ltd., Milton, Queensland, Australia.     

高炉喷吹生物炭研究进展

高炉喷煤可以降低焦比,但同时加剧温室效应和环境污染.近年来人们开始探索可以替代煤粉的新型燃料,如生物炭、兰炭、城市有机废物等,其中生物质因其来源丰富、环境友好而受到广泛关注.生物炭中的碳含量与煤相近,具备替代煤粉用于高炉喷吹的基本条件.对高炉喷煤技术、生物炭的制备和高炉喷吹生物炭的国内外现状进行了论述,并将生物炭的理化...     

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。     

鞍钢高炉喷吹燃料的综合特性分析

为了充分掌握大喷煤条件下高炉喷吹不同燃料的可行性,对几种可用于鞍钢高炉喷吹的不同煤级煤种进行了深入研究,主要包括喷吹煤种的工业分析、元素分析,灰成分、发热量、可磨性、着火点和爆炸性、灰熔特性、燃烧性、反应性分析等。同时,结合动力学计算来表征不同煤种的化学反应特性差异。结果表明,随着煤级的升高,煤的软化温度逐渐提高,这主要和氧化钙的作用相关;提质煤和兰炭具有优异的燃烧和气化特性,并且其价格优势明显,安全爆炸性和可磨性符合高炉喷吹要求,搭配混合燃料进行高比例喷吹时有利于燃料结构优化和喷吹成本控制。     

邯钢高炉喷煤煤种的选择研究

基于邯钢高炉喷煤现场,对其所用无烟煤及拟用烟煤进行了工业分析、喷流特性、爆炸性、着火点、灰熔点以及配煤燃烧率系统研究。结果表明,大湾煤是邯钢高炉喷吹烟煤的首选煤种,其次是准联煤和老张沟煤;长治煤是邯钢高炉喷吹无烟煤的最佳煤种。大湾烟煤与长治无烟煤组成的混煤为较好的选择。     

莱钢1000m3高炉喷煤系统设计特点及生产实践

介绍了莱钢两座1000m 3高炉喷煤系统的设计特点和顺利投产后迅速达产达效的情况。喷煤系统工程采用短工艺流程、循环利用高炉废气、整体流化上出料、仓流化装料方式等多项先进技术。通过喷煤设备技术改造,优化高炉操作,强化冶炼,短时间内实现了高炉利用系数2.8t/m 3.d以上和最低入炉焦比315kg/t。     

武钢高炉经济性喷煤研究

为了使武钢高炉达到经济性喷煤的目标,通过煤资源调查,掌握了适合武钢喷吹用煤的煤源情况;通过对高炉大煤比条件下的风口理论燃烧温度进行计算,分析了影响高炉喷煤的主要因素;通过对武钢高炉炉尘中的残碳量及其来源进行分析,发现目前操作条件下炉尘中源自煤粉的碳量占总碳量的10%左右,此结果已用于研究未燃煤粉在炉内的利用状况及评估高炉喷吹煤粉的燃烧情况;通过对高炉操作指标进行统计分析,发现煤比在160~170 kg/t时,高炉燃料比较低。实践结果表明,上述经济性喷煤技术在5号高炉应用后,在煤比仅略增加0.8 kg/t的情况下,焦比降低了9.7 kg/t。     

淮钢高炉喷煤设计特点及实践

淮钢新建2×450 m3高炉喷煤系统,中速磨制粉,布袋1级收粉,采用双系列串联罐、喷吹总管加炉前分配器的单管路喷吹方式,以及采用适应高喷煤量的高炉操作,使喷煤量很快达到设计要求9～11 t/h.     

无气柜式煤调系统的远程监控

针对南钢两座高炉 ,1座JN43 - 80型 42孔焦炉 ,在无气柜的情况下 ,对煤气平衡调度而开发的远程监控系统进行了阐述     

高炉喷吹煤粉优化选择

 高炉喷吹煤粉是目前高炉冶炼降低焦比最为有效的措施之一,然而高炉喷吹煤粉种类繁多,为了保持较高的煤/焦置换比和降低高炉冶炼喷吹成本,需要对喷吹煤种进行合理的选择和搭配。以国外某钢厂提供的12种煤粉为原料,系统进行了其作为高炉喷吹煤粉所关注的基础性能和工艺性能分析,根据测试结果对不同煤粉进行高炉喷吹的综合性能进行了研究,为钢厂高炉喷吹煤粉的优化选择提供指导。研究结果表明,提供的12种煤粉中4号为高变质无烟煤,6号、7号和12号为高变质贫瘦煤,5号、10号和11号为低变质贫瘦煤,1号、2号、3号、8号和9号为低变质烟煤。相比于国内高炉喷吹用的煤粉,该钢厂提供的12种煤粉具有较低的灰分和硫含量,进行高炉喷吹能够降低渣量和入炉硫负荷;同时,所选煤粉的喷流性、流动性较高,灰熔融温度较高,低变质烟煤具有强爆炸性,不能单独作为高炉喷吹使用;不同煤粉的可磨性和燃烧性能差异较大,成为限制其应用于高炉喷吹生产的关键。结合不同煤粉高炉喷吹综合性能评价指标的计算结果,优选8号、10号、11号和12号煤粉作为高炉喷吹煤粉使用。考虑不同煤粉的采购成本,12号煤粉用于高炉喷吹降低冶炼的成本最为显著。     

Failure Mechanism and Material Requirements for Coal Lance in Blast Furnace

 Abstract： Pulverized coal injection (PCI) is a key technology in modern ironmaking by blast furnace (BF) and the life of injection lance has a great influence on PCI operation and on normal running of blast furnace. It is found that the main reasons for the failure of the lances are their outer surface oxidation and the inner surface erosion through monitoring some lances used in BF. The outer surface oxidation of the lances made of lCr18Ni9Ti is inevitable under high hot blast temperature condition through thermodynamics analysis. A mathematical model for calculating the temperature of common monocular coal lance had been developed according to the principles of mass and energy balance. Increasing temperature and flow velocity of the hot blast would cause a rise in the lance temperature. The influence of hot blast temperature is more obvious. The lance temperature would decline when compressed air flux increases. Conveying technology of dense phase pulverized coal is beneficial to extending lance′s life because decreasing solid-gas ratio would intensify erosion and burning loss. The anti-oxidation temperature of lance materials needs to be over 1000 ℃ for BF intensified smelting. In order to increase the resistance to oxidation of the coal lance′s outer surface, oxidation-resistant steel or Al coating stainless steel is the appropriate material for BF use. Employing the metal surface treatment technology to enhance the hardness of the coal lance′s internal surface could prolong the service life of coal lance.