Laboratory investigation into reduction the production of dust in basic oxygen steelmaking

Large amounts of dust produced in basic oxygen steelmaking not only reduce the yield of metal, but also increases the dedusting load. Based on the different vapour pressure of Mn, Fe, V, Mo, disparate alloys were added into induction furnace with various carbon content, and different portions of mixed gas of CO₂ and O₂ were blown into the furnace. Through laboratory investigation of the production behaviour of dust in basic oxygen steelmaking, the dust production mechanism was studied. The experiments prove that the production of dust in basic oxygen steelmaking depends on both entrainment of the bubbles and evaporation of elements. As the reactions proceed, the dust particle size shows a tendency to become larger. With the increasing of CO₂ blowing rate, the amount of dust produced by entrainment of the bubble increases, while which produced by evaporation of elements decreases, and dust size diminishes. Blowing a certain portion of CO₂ into the bath not only contribute to the utilisation of CO₂, but also reduce dust and obtain higher quality converter gas. The purpose of energy saving and consumption reducing can be implemented finally.     

Influence of bottom-blowing gas species on the nitrogen content in molten steel during the EAF steelmaking process

In modern EAF steelmaking process, control of the nitrogen content of molten steel has become more and more important and bottom-blowing technique has been widely applied to promote the molten bath fluid flow, accelerate the metallurgical reaction and improve the quality of molten steel. In this study, the influence of bottom-blowing gas species on the nitrogen content in molten steel during EAF steelmaking was systematically investigated and analysed. Combining the induction furnace experiments and theoretical analysis, the kinetic models of nitrogen change in molten steel with bottom blowing N₂, Ar and CO₂ were established theoretically and validated experimentally. Meanwhile, the thermodynamic laws and agitation capacity of different bottom-blowing gases were also clarified. Then, based on the industrial application research, the metallurgical effects, especially nitrogen removal, with different bottom-blowing gases were also studied and finally, a new concept was proposed for cyclic utilisation of CO₂ in the EAF steelmaking process.     

基于石灰窑回收CO2用于炼钢的关键技术分析

针对CO2在首钢京唐300 t转炉的成功试验，分析了从石灰窑回收CO2用于炼钢的关键技术，重点讨论了从石灰窑回收CO2的工艺路线选择、石灰窑烟气CO2提浓技术、石灰窑烟气的预处理技术、提纯技术、存储输送技术、转炉顶吹O2 CO2混合喷吹技术和底吹CO2技术等。并通过试验验证了CO2用于转炉冶炼，不仅可以提高炼钢冶金效果，而且可以增加转炉煤气回收量。认为该工艺的开发可形成石灰窑与炼钢之间的碳素流循环，有利于节能减排，降低碳排放。     

降低转炉钢铁料消耗生产实践

阐述武钢炼钢总厂二分厂通过保持合理炉容比,合理配加废钢,优化转炉造渣工艺,控制转炉喷溅,加强转炉维护,应用转炉投弹式检测技术和自动炼钢技术,开发大流量底吹工艺等措施,降低转炉钢铁料消耗,已取得较好的经济效益.     

In‐Situ Measurement of CO‐ and CO2‐Concentrations in BOF Off‐Gas

Improvement of the efficiency and productivity of steelmaking requires accurate and real‐time process information to precisely adjust the tapping conditions. The response time of BOF process control systems is commonly depending on the time needed for off‐gas sampling and analysis. A FTIR based measurement system was adapted and installed at an industrial steel converter of ArcelorMittal España S.A. in Aviles. An advanced data interpretation routine based on the quantum mechanical fundamentals of remote infrared (IR) spectroscopy was developed to enable precise determination of the {CO}‐ and {CO₂}‐concentrations, resp. their ratio, in the off‐gas. The results of the industrial measurement showed the ability of the FTIR based system for real‐time measurement of temperature, {CO}‐ and {CO₂}‐concentrations in the hot and dusty off‐gas. The influence of dust at the chosen defined optical path lengths in the IR wavelengths region can be neglected, but the collector lens clean has to be kept clean.     

现代转炉炼钢技术（一）

简要回顾了转炉炼钢技术的发展历史,并对转炉炼钢的重要技术进行较为详细的描述。这些技术包括铁水预处理、转炉基本操作工艺及品种质量、计算机控制炼钢、顶底复合吹炼、溅渣护炉与长寿复吹、转炉节能与负能炼钢。最后还对21世纪转炉炼钢技术的发展趋势作了展望。     

干法除尘工艺在200 t半钢炼钢转炉上的应用

 针对攀钢集团西昌钢钒有限公司200 t半钢炼钢转炉采用干法除尘工艺时出现的泄爆率高、煤气回收量低、除尘效果差等问题,结合半钢炼钢生产实际,对干法除尘泄爆原理及其在半钢炼钢转炉应用的难点进行分析,在此基础上对转炉风机转速、供氧制度、造渣加料制度及氧枪枪位制度等工艺参数进行改进。改进后的应用效果表明,200 t半钢炼钢转炉泄爆率由7.60%降低到0.08%,煤气回收量由54.6 提高到123.6 m3/t ,除尘灰回收量显著增加;同时,转炉冶炼周期缩短4 min,氧耗降低2.4 m3/t,除尘效果更好,保证了转炉冶炼的顺行,大大降低了炼钢能耗。     

Reduction of CO2 Emissions from Steel Plants by Using Steelmaking Slags for Production of Marketable Calcium Carbonate

By carbon dioxide mineralization, CO₂ can be stored safely and leakage‐free for very long times. Owing to their high calcium content, steelmaking slags are suitable for mineral carbonation. In a country like Finland, where no suitable geological formations for CO₂ storage seem to exist, steelmaking slag carbonation offers an important CO₂ emissions reduction option for steel plants. If calcium could be extracted selectively from the slags prior to carbonation, a pure, and possibly marketable, calcium carbonate may be produced. This could replace some of the natural and synthetic CaCO₃ used in industry, combining savings in natural resources with CO₂ emissions reduction. Development work on the production of pure calcium carbonate from steelmaking slags by carbonation is presented in this study. Selective extraction of calcium from steelmaking slags was investigated using various solvents. Precipitation of CaCO₃ from dissolved calcium at atmospheric pressure was also investigated. Amongst the various tested solvents ammonium salt solutions (NH₄Cl, CH₃COONH₄, NH₄NO₃) were found to be the most promising for selectively extracting calcium from steel converter slag. These solvents dissolved calcium efficiently also from desulphurization slag, while extraction of calcium from two other types of slag was poor. CaCO₃ was successfully precipitated from the solution containing ammonium salt and dissolved steel converter slag.     

Combined blowing with three ‐ hole lance in a sidewall blowing converter

Traditionally, in stainless steelmaking converters, oxygen has been blown by a one‐hole lance (1 HL) and sidewall tuyères. In order to reduce the tap‐to‐tap time, the multi‐hole lance has been used for oxygen blowing. The aim of this work was to develop blowing practise for a multi‐hole lance to reduce the tap‐to‐tap time and minimise metal splashing and spitting in the sidewall blowing converter (chromium converter). In the chromium converter the chemical energy of liquid ferrochrome (which contains 4 % silicon and 7 % carbon) is utilised for scrap melting by oxidising the silicon and the part of carbon. The research has been made by a dynamically scaled water model and full‐scale converter. Used parameters were the gas flowrate from sidewall tuyères and lance, lance height, charge weight and position of multi‐hole lance. Splashing has been measured during blowing from walls (splashing) and mouth of the converter model (spitting). The model tests indicated less splashing and spitting by the three‐hole lance (3 HL) than traditional 1 HL. The 1 HL caused strong skulling of the converter cone. By 3 HL blowing the position of the lance has a remarkable effect on the direction and the amount of splashing and lance life. Because of hot metal‐slag splashes, the life time of the 3 HL was halved by position 1 (compared to 1 HL). With the lance position 2 the splashing decreased by approx. 50% in model tests and lance life time increased by ~ 50% (compared to 1 HL) in the full‐scale converter. The model agreed well with the full‐scale converter. According to the process tests, the nominal productivity of the chromium converter has increased 15 % and depending on the refining practise and the silicon content of ferrochromium the lining life has increased 20 ‐ 30 %. In the future the multi‐hole lance will be tested in the AOD vessel.     

120t转炉底吹CO2工艺研究及应用

介绍了某钢厂采用底吹CO2工艺,转炉冶炼CSP中低碳钢过程的变化,探究底吹CO2的工艺优势,为后续工艺优化提供借鉴。通过在120 t顶底复吹转炉进行底吹CO2工艺试验研究,分析了底吹CO2对钢水成分、炉渣成分、氧气消耗、钢中氮氧含量的影响。试验结果表明:底吹CO2工艺替代常规工艺切实可行,且有明显的工艺优势。底吹0.97 m3/t CO2冶炼CSP中碳钢,终点碳质量分数大于0.08%时,终点锰质量分数提高0.05%,渣中氧化铁质量分数降低1.18%以上,氧气单耗下降4 m3/t,同时终点氮、氧含量有所下降。上述效果随着终点碳质量分数下降呈减弱趋势,当碳质量分数小于0.055%时,与常规工艺趋于一致。     

烟气分析动态控制炼钢技术的实践应用

介绍马钢120 t转炉烟气分析动态控制炼钢技术的多功能应用：启用自学习,自适应功能,针对不同原材料条件,优化供氧造渣制度,实现全自动炼钢新模式;实践证明,本技术实施后,有效监控转炉底吹搅拌效果,w(［C］)×w(［O］)浓度积值在0.001 2～0.003 0占78.8％;利用烟气分析CO浓度变化趋势指导操作,降低喷溅率在4.0％以下;优化吹炼工艺,强化脱磷脱硫效果;准确预报钢水终点氧含量,提高脱氧合金化效果,降低吨钢成本5元;增加煤气回收量9 m3/t钢和提高w(CO)5%～8%等显著成效。     

80t复吹转炉冶炼硬线钢快速成渣工艺的实践

国内某钢厂转炉冶炼硬线钢一直存在着成渣速度慢、脱磷率低等问题。在热力学分析的基础上,通过大量的生产数据整理和实验室研究,对其80t复吹转炉快速成渣脱磷工艺进行了改进。通过对装料制度、供氧制度和底吹气体流量进行优化,取得了很好的冶金效果。工业试验结果表明：采用合理的造渣工艺,能够实现快速成渣、早期脱磷,平均出钢w（C）能达到0.253%,而w（P）降至0.011 7%,平均吹炼时间缩短近3min。     

副枪及炉气分析在半钢炼钢中的应用

 对副枪、炉气分析相结合在半钢炼钢中使用存在的问题进行讨论,通过生产试验,提出在冶炼中期利用炉气分析曲线指导过程控制与操作,预报炉渣返干与喷溅,进行过程控制动态炼钢。在吹炼后期,CO与CO2曲线交叉后（即w（C）<0.20%时）,炉气分析C预报较准确,利用其进行终点碳控制,实现不倒炉炼钢。在吹氧量为80%~85%与停吹氧30 s后,副枪使用T或TS探头进行测量,对炉气分析模型温度进行修正,可提高炉气分析模型终点温度控制的准确性,减少副枪探头成本消耗。当入炉条件信息不准确时,副枪与炉气分析相结合使用是较合理的选择。     

Mathematical Modeling of the Energy Consumption and Carbon Emission for the Oxygen Blast Furnace with Top Gas Recycling

The ironmaking process is the most significant source of CO₂ emission in the iron and steel industry, which generates large quantities of greenhouse gases. Recently, oxygen blast and top gas recycling have been applied to the blast furnace to improve the energy efficiency and reduce the pollution from the ironmaking process. However, as a new ironmaking technology, the oxygen blast furnace with top gas recycling (TGR‐OBF) is still under development. This paper focuses on the investigation of the energy consumption and carbon emission for the TGR‐OBF process by modeling the stack, the bosh, the combustion zone, and the gas recycling system. Effects of the key parameters in the TGR‐OBF process on the carbon consumption of reactions and the energy consumption of the system are investigated by orthogonal experiments. Our results indicate that the TGR‐OBF process has the advantages of reducing energy consumption and CO₂ emission. The low temperature and high reducing environment in the new furnace is favorable to lower the coke gasification and increase the reaction rate of iron oxide. The recycling of the top gas can significantly reduce CO₂ emission, and the main advantage comes when the stripped CO₂ is stored.     

沙钢180t转炉自动炼钢控制工艺的建立与实践

以副枪系统和二级冶金模型为基础,通过优化原材料条件,建立转炉加料、底吹搅拌和供氧等吹炼过程自动控制工艺,以及优化系统操作参数和模型参数等措施,实现了180t转炉自动化炼钢,转炉出钢命中率由25%提高到83%以上,且吹炼过程稳定,转炉生产周期缩短了4min,终渣全铁质量分数平均降低了2.4%,提高了转炉炼钢的金属收得率。     

180 t转炉底吹和顶-底复吹射流与熔池作用的水模型研究

根据180 t转炉的实际生产情况,以修正的Froude准数为相似准数,建立几何相似比10 ： 1水模型,进 行了四孔对称单纯底吹试验,并在最佳的底吹工艺参数下(底吹最佳位置为喷嘴所在同心圆直径:转炉熔池直径= 0. 3处;最佳流量为0. 7 m³/h,均混时间18. 2 s),通过改变顶吹氧枪的气体流量和吹炼枪位进行了顶底复吹转炉射 流与熔池作用的试验。结果表明,在底吹条件下,增加顶吹工艺(最佳枪位150 mm,最佳流量39 m³/h),熔池平均 的均混时间减少了 5.6 s, 180 t转炉顶底复吹可显著提高经济效益。     

国内外转炉炼钢技术的新进展

回顾了转炉炼钢三次技术进步的历程,叙述了转炉炼钢工艺技术的开发、分类及主要冶金特点,介绍了世界复吹转炉工艺技术的应用情况,提出相关钢厂应研发少渣炼钢工艺、复吹转炉高效吹炼技术和吹炼终点动态控制的三项建议.     

Top gas recycling blast furnace developments for ‘green’ and sustainable ironmaking

Abstract

The ultralow CO₂ steelmaking blast furnace process (ULCOS-BF) aims at minimising the CO₂ emissions of the BF by at least 50%. This process is based on the replacement of hot blast by oxygen, the recycling of hot decarbonated top gas into the lower shaft and normal hearth tuyeres, and the capture of CO₂ and its storage in a geological trap (full CO₂ capture and storage process). The paper highlights the main technologies of this process and the expected benefits for CO₂ mitigation. The ULCOS-BF has been demonstrated during three campaigns of 7 weeks each by coupling the LKAB experimental BF in Luleå to a pilot vacuum pressure swing absorption unit for CO₂ removal. The concept, preparation and results of the campaigns are described.     

120 t转炉底吹供气系统控制模型与应用效果

根据鞍钢120 t转炉底吹供气系统的应用情况,基于PID调节算法建立了转炉底吹系统控制模型,可以实现供气管道气体流量的迅速、准确、稳定控制,满足生产工艺要求,使底吹元件在炉役期内可以保持稳定的形态和良好的透气性能,不易堵塞。该转炉进行底吹供气控制模型、设备和工艺优化后,钢水终点碳氧积由0.00316降低为0.00273,终点炉渣T.Fe含量降低1.69%,吨钢降低成本12.2元,经济效益显著。     

300 t复吹转炉底吹系统优化模拟

 顶底复合吹炼转炉炼钢法是当下主流的炼钢方法,底部供气元件的种类、支数、排布方式和底吹供气强度直接影响着转炉熔池的混匀效果,合理的流场不仅可以降低生产成本,更能缩短冶炼周期,增加企业效益。基于冷态水模拟以及CFD数值模拟手段各自的研究特点,以某钢厂300 t转炉为原型,将不同底吹条件下熔池的混匀时间、死区以及弱流区体积作为评判依据,对300 t转炉的底枪排布方式、底吹供气模式(非均匀供气和均匀供气)以及底吹供气强度进行了系统研究,研究结果表明,当底枪排布位置由0.3D(D为炉底直径)到0.5D,底吹系统对炉壁处钢液的搅拌能力明显增强,但熔池内死区以及弱流区体积却会明显增加,使得整个熔池混匀时间增长;在对适宜底吹强度研究发现,当熔池底吹强度的临界值为0.28 m3/(t·min),此底吹强度下对熔池的搅拌效果最好;底吹系统对熔池的搅拌效果会随着供气模式的不同而改变,当底吹流量分配为2:1时,底吹系统对熔池的搅拌效果最佳,均匀供气模式(1:1)次之,而当分配比为3:1和4:1时,由于熔池的大流量侧供气强度相对较大,会极大影响底吹系统对熔池的搅拌效果。