40 t偏心电弧炉底吹工艺数值模拟及工业试验研究

通过对某钢厂40 t偏心电弧炉底吹工艺建立数学模型，利用流体计算软件Fluent数值模拟了不同底吹条件下电弧炉熔池内的流体流动特征，分析了不同底吹流量对流体流动的作用规律。结果表明：随吹气量的增大,熔池表面平均速度不断增大，得出最优的吹气量为30～40 m³/h。同时结合工业生产数据发现，采用底吹搅拌技术后能加速电弧炉熔池的传热和传质速度，缩短冶炼时间，降低生产成本。     

EBT区域底吹流量变化对电弧炉炼钢的影响

 电弧炉底吹是加速熔池流动、减少EBT区域死区、改善炼钢反应的重要手段，底吹流量变化会影响电弧炉熔池流动和冶金效果。利用Fluent软件研究了100 t电弧炉EBT区域附近不同底吹流量的熔池流动特性，发现当EBT区域底吹流量从100增加至150 L/min时，熔池平均流速提高18.03%，死区面积减少22.06%；当进一步增加至200 L/min时，熔池流速和死区面积变化幅度降低。在此基础上，通过100 t电弧炉炼钢试验研究了不同底吹条件下的冶金效果，发现底吹可显著降低电弧炉钢铁料消耗和石灰消耗，缩短冶炼周期，降低炉渣FeO质量分数和钢液碳氧浓度积；随着EBT区域底吹气体流量从100增加至150 L/min，冶金效果进一步得到改善。     

不同工艺对100 t直流电弧炉冶炼纯净钢的影响

在电弧炉50%热装铁水条件下,对比了不同冶炼工艺对电弧炉冶炼周期、吨钢氧耗和吨钢电耗的影响。试验结果表明,在电弧炉热装铁水比相同的条件下,采用不同的供氧制度能够有效缩短冶炼周期,提高电弧炉钢水化学成分命中率。     

交流电弧炉电气运行仿真研究

应用MATLAB语言的仿真功能,对创建的电弧炉数学模型在不同的电参数条件下进行仿真,形成电气图、供电效率曲线图和电气运行曲线图,结合约束条件,定量给出电弧炉合理的操作区间,为电弧炉运行优化和供电制度的建立提供理论支持。     

复合搅拌工艺电弧炉熔池混匀与界面传质特性

全废钢电弧炉冶炼过程中缺失C-O反应,加之熔池呈浅碟型,单一搅拌方式搅拌强度低,反应动力学条件差,是制约电弧炉高效冶炼的主要原因之一。为了改善电弧炉冶炼过程熔池内动力学条件、提高冶炼效率,采用物理模拟方法,研究了单一搅拌方式形成的流场特性,在此基础上进一步探究了不同复合搅拌组合条件下熔池混匀与界面传质特性,探究最佳的复合搅拌方式。研究结果表明,氧气射流、侧吹形成的流场相似,主要分布在熔池上部和中上部,复合搅拌不能消除单一搅拌形成的弱搅拌区域;底吹形成的流场可以贯穿整个熔池,但在远离流股中心处和底部仍然存在弱搅拌区域,与射流复合搅拌可以大幅提高搅拌效果,平均混匀时间为53～86 s。在射流和底吹复合搅拌的死区部位添加侧吹喷枪,形成“三元”复合搅拌,可以进一步强化熔池搅拌效果,平均混匀时间为31～68 s,远低于“二元”搅拌,但熔池内部混匀效果与钢-渣界面传质效果对搅拌工艺参数要求并不一致,甚至相反。综合在“三元”搅拌条件下的冶金效果,1组和5组综合冶金效果最佳。     

齐钢高功率45吨偏心底炉通过省级鉴定

齐齐哈尔钢厂将从法国引进的一台老式电弧炉改造成具有八十年代水平的偏心底出钢EBT电弧炉获得成功。于1992年11月6日在哈尔滨通过黑龙江省冶金厅组织的技术鉴定。齐钢1990年从法国引进的二手HP45t电弧炉,采用低位出钢槽出钢,总体设计为70年代水平,与目前国际先进的EBT电弧炉相比,这种老式电弧炉在设计和操作上都存在一些缺点,钢水二次氧化严重、出钢温降大,冶炼时间长,耐火材料及电极消耗高,炉体寿命低,齐钢在原电弧炉的基础上,在不破坏原电弧炉基本结构的原则下,设计出具有自己特点的电弧炉。该装置实现了氢气幕保护封闭无渣出钢,平面旋转档板式水口开闭,钢水电子称自动计量和显示,与     

70 t 电弧炉炼钢集束射流氧枪流场的数值模拟及应用

用CFX5.7.1 软件对电弧炉炼钢用集束射流氧枪和普通氧枪的射流特征进行了数值模拟和冷态试验。结果表明,集束射流氧枪比普通超音速氧枪射流长,射流集中、衰减慢。在鄂钢70 t Consteel电弧炉 上应用表明,使用集束氧枪后平均电耗由338 kWh/t降低到219 kWh/t,电极消耗未变,为1.86 kg/t,氧耗由 51.6 m³/t提高到60.3 m³/t。     

基于多相流数值模拟的电弧炉脱碳速度研究

利用CFD软件对某厂150 t电弧炉进行了三维三相流数值模拟.将射流冲击深度的数值模拟结果与水模实验外推结果进行了比较,两者吻合较好.模拟结果表明;由于氧气射流的冲击,在熔池表面形成未被渣层覆盖的裸露钢液面,裸露钢液面是氧气与钢液的主要接触区域.利用基于红外烟气分析技术的脱碳模型,测定电弧炉炼钢过程中不同供氧流量下的脱...     

虚拟模拟炼钢实践与分析

介绍了三届国际虚拟炼钢挑战赛的情况,对挑战赛中应用的电弧炉模拟、二次精炼模拟和连铸模拟中的重点和难点进行详实分析。应用该模拟可以增强对冶金原理的理解和冶金工艺的掌握。     

电弧炉电能需求的生产实践与评价

电耗是电弧炉的重要技术指标之一,在当前发电行业背景下,降低电弧炉电耗具有显著的经济和环境效益。根据典型电弧炉企业生产数据,系统分析各项工艺参数与电耗之间的关系,并进一步评价了各种方法降低电耗的环境效益。结果表明,优化供电制度和强化供氧是具有良好环境效益的节电手段。对于连续加料电弧炉,天然气喷吹对降低电耗的作用被极大减弱,天然气消耗与电耗的相关系数为-1.13 kW·h/m³,其应用不利于CO₂减排。尽管兑加铁水可以显著降低电耗,但是兑加40%(质量分数)铁水的连续加料电弧炉能耗和碳排放量分别是全废钢连续加料电弧炉的2.25和2.50倍,不利于推动钢铁工业节能减排工作。因此,降低电弧炉电耗需要通过增加电弧炉中化学能和物理热的供应及减少能量损失的手段来实现。     

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。     

Simulation and application of pulsating bottom-blowing in EAF steelmaking

Pulsating bottom-blowing was proposed to strengthen the electric arc furnace (EAF) molten bath stirring. The fluid flow characteristics and stirring effects of different pulsating bottom-blowing modes on EAF molten bath were studied through water model experiments and numerical simulations. The mixing time was measured by water model experiments and the flow field characteristics of EAF molten bath were simulated by numerical simulations. Compared with conventional bottom-blowing, pulsating bottom-blowing can accelerate the fluid flow velocity and improve the stirring of molten bath. With pulsating bottom-blowing, the molten bath fluid flow field is more disorder, the fluid flow velocity increases and the dead zone volume decreases. Compared with EAF steelmaking with conventional bottom-blowing conditions, pulsating bottom-blowing technology can improve the metallurgical effects and the molten steel quality in EAF steelmaking with lower FeO content of final slag, lower phosphorus content and carbon-oxygen equilibrium of final molten steel, and lower temperature deviation.     

Simulation of Flow Fluid in the BOF Steelmaking Process

The basic oxygen furnace (BOF) smelting process consists of different chemical reactions among oxygen, slag, and molten steel, which engenders a vigorous stirring process to promote slagging, dephosphorization, decarbonization, heating of molten steel, and homogenization of steel composition and temperature. Therefore, the oxygen flow rate, lance height, and slag thickness vary during the smelting process. This simulation demonstrated a three-dimensional mathematical model for a 100 t converter applying four-hole supersonic oxygen lance and simulated the effect of oxygen flow rate, lance height, and slag thickness on the flow of molten bath. It is found that as the oxygen flow rate increases, the impact area and depth increases, which increases the flow speed in the molten bath and decreases the area of dead zone. Low oxygen lance height benefits the increase of impact depth and accelerates the flow speed of liquid steel on the surface of the bath, while high oxygen lance height benefits the increase of impact area, thereafter enhances the uniform distribution of radial velocity in the molten steel and increases the flow velocity of molten steel at the bottom of furnace hearth. As the slag thickness increases, the diameter of impinging cavity on the slag and steel surface decreases. The radial velocity of liquid steel in the molten bath is well distributed when the jet flow impact on the slag layer increases.     

Effect of oxygen flow rate and temperature on supersonic jet characteristics and fluid flow in an EAF molten bath

A new operation method for the oxygen lance of an electric arc furnace (EAF) was proposed, meeting the simultaneous demand for low oxygen flow rate and high stirring power in a particular smelting stage. When the oxygen flow rate needs to be reduced, the stirring power of the jet can be improved by increasing oxygen temperature properly. Free supersonic jet characteristics at different flow rates and stagnation temperatures were studied by numerical simulation and validated by a jet measurement experiment. The results showed that the designed Mach number can be maintained by coupling adjustment of flow rate and stagnation temperature. Meanwhile, a three-phase, full-scaled numerical model for a commercial 75t EAF with three oxygen lances on the side-wall was established to study the fluid flow in the molten bath. The velocity distribution, cavity profile and total kinetic energy of the EAF bath induced by the impingement of supersonic jets onto the liquid bath were discussed and compared. It was found that the fluid flow characteristics of the EAF molten bath can be improved even if the oxygen flow rate was reduced as long as the oxygen temperature could be increased reasonably.     

210t转炉底吹供气参数优化模拟研究

摘要：为优化某厂210t转炉底吹供气效果,利用气 液两相流相互作用数值模拟方法,研究了底吹元件数量、布置方式和供气强度变化对熔池搅拌效果的影响。通过对8支、10支、12支底吹元件数量下的作用效果分析,得出12支底吹元件布置在0.63D(D为熔池直径)的同心圆上时,熔池内钢液流动相对较稳定,“死区”比例最低,混匀时间最短。随着底吹强度增大,“死区”面积减少,混匀时间缩短,气流对炉底的侵蚀作用加剧。底吹强度为0.05m3/（min·t）时,“死区”比例为23.9%,底吹强度为0.10m3/（min·t）时,“死区”面积大幅降低,进一步提高至0.20m3/（min·t）时,“死区”比例降低至4.6%;当底吹强度增加至0.15m3/（min·t）时,熔池混匀时间大幅降低至30s,继续提高底吹强度,混匀时间降幅不大,将底吹强度控制在0.10~0.15m3/（min·t）之间比较合理。     

Modeling of an Impinging Oxygen Jet on Molten Bath Surface in 150 t EAF

 A transient three-dimensional mathematical model has been developed to analyze the three-phase flow in a 150 t EAF (electric arc furnace) using oxygen. VOF (multiphase volume of fluid) method is used to simulate the behaviors of molten steel and slag. Numerical simulation was conducted to clarify the transient phenomena of oxygen impingement on molten bath. When oxygen jet impinges on the surface of molten bath, the slag layer is broken and the penetrated cavity in molten steel is created. Simultaneously, the wave is formed at the surface of uncovered steel on which the slag layer is pushed away by jet. The result of numerical simulations shows that the area and velocity of uncovered steel created by impingement, jet penetration depth change from 0.10 m2, 0.0125 m/s, 3.58 cm to 0.72 m2, 0.1445 m/s, 11.21 cm, when the flow rate of an oxygen lance varies from 500 to 2000 m3/h. The results have been validated against water model experiments. More specially, the relation between the penetration depth and oxygen flow rate predicted by numerical simulation has been found to agree well with that concluded by water model.     

Simulation and Application of Swirl‐Type Oxygen Lance in Vanadium Extraction Converter

Stirring effects and impacting characteristics of conventional and various swirl‐type oxygen lances (Swirl angles are 5°, 10°, and 13°, respectively) on the molten pool were studied. The mixing time, impacting depth and impacting diameter were measured by water model experiment. The flow field characteristics of gas–liquid two phase flow were simulated using Fluent software. It is found that 10° swirl‐type oxygen lance injection can get the shortest mixing time which is only 47.6 s. The area surrounded by isovelocity is larger in molten pool when injecting by the swirl‐type oxygen lance. When injecting by the 10° swirl‐type oxygen lance, the area is the largest and the flow velocity of liquid steel is the highest. On this basis, the 10° swirl‐type oxygen lance was experimented in 150 t vanadium extraction converter. The experiment shows that the swirl‐type oxygen lance can guarantee the normal smelting process. Compared with the conventional oxygen lance, the reduction ratio of vanadium content in semi‐steel is 17.8%, vanadium extraction rate is increased by 5.1%, V₂O₅ grade of vanadium slag is increased by 0.93% and iron loss is reduced. It provides a new technology to improve the recovery of vanadium resources in converter.     

Development and application of electric arc furnace combined blowing technology

A number of electric arc furnace (EAF) plants in China use high proportions of hot metal in the charge because of availability of excess liquid iron at the steelworks and/or because of the high price of scrap relative to hot metal. Liquid steel costs are still higher than the basic oxygen furnace as the EAF is not as efficient when refining liquid iron. EAF combined blowing technology has been modelled and installed in industrial plants with the aim of increasing stirring and hence improving refining. The industrial application of the combined blowing technology in a number of steel plants indicates that the combined blowing technology of EAF can effectively improve the pool stirring strength and reaction dynamics condition of the molten pool, and optimise production.     

20t电弧炉冶炼工艺优化

针对莱钢特钢厂20t电弧炉冶炼过程中存在的挂料现象、冶炼周期长、电耗高、氧气利用率低、炉衬渣线侵蚀严重、炉衬寿命低等问题,采取了优化入炉废钢结构、铁水热装、优化供电制度、泡沫渣埋弧操作、炉门氧枪供氧技术、油氧助熔技术和炉衬喷补等技术,使20t电弧炉冶炼周期缩短26min,变压器利用系数提高41.51%,炉体寿命提高286炉次,保证了连铸的顺行。     

转炉超音速氧枪喷头磨损后的吹炼特性变化

 转炉氧枪喷头会随枪龄的增加发生不同程度的侵蚀,为了探究氧枪喷头侵蚀程度对超音速气体射流吹炼特性的影响,建立了120 t转炉及超音速氧枪的三维全尺寸几何模型,研究了氧枪喷头不同磨损角度对气体射流特性、熔池速度及壁面侵蚀的影响。发现随着磨损角度增加,射流速度衰减加快,射流核心区长度缩短,同一等速线长度缩短,射流中心最大速度和最大速度点距中心距离增大。射流动压衰减速度随磨损角度增加而加快,磨损角度由0增至20°,距喷头端面1.5 m处最大动压减小了14.84%,14 000 Pa等压线包围面积由0.038 m2减小至0.002 m2。钢液面处高速区面积随着磨损角度增加而减小,死区面积随着磨损角度增加而增大。熔池纵截面高速区域主要分布在冲击凹坑和底吹元件附近,低速区域主要分布在熔池底部,死区主要分布在熔池底部中心和炉壁下部区域。当熔池深度小于0.6 m时,顶吹气流对熔池的搅拌起主要作用,磨损角度增加,熔池搅拌能力变弱,熔池横截面高速区面积减小,低速区和死区面积增大;当熔池深度大于0.6 m时,底吹气流对熔池搅拌起主要作用,高速区面积基本不变。渣-金作用区域和底吹流股附近流体湍动能较大、壁面剪切应力较为集中,该部位耐火材料侵蚀严重。熔池壁面附近流体湍动能和壁面剪切力随磨损角度增加而降低,转炉炉衬侵蚀速度减小。