COREX流程熔炼煤的选择

COREX流程的高效生产主要取决于熔炼煤的选取，使用性能适当的熔炼煤可以减少整个流程的净能耗，降低生产成本，并且摆脱对焦炭的依赖，在COREX流程中，主要检测熔炼煤的有效热值、成分和热稳定性，这些指标分别从煤耗、还原气利用率和固定床高度方面影响着整个生产流程，较高的有效热值保证了熔炼造气炉内具有足够的热量熔炼海绵铁，熔炼煤的成分通过气体利用率来确保还原竖炉内具有足够的还原气还原铁矿石，为了减少焦炭的用量，熔炼煤还必须具有一定的热稳定性来形成一个稳定的固定床。     

Analysis of Material and Energy Consumption of Corex C3000

The first Corex C3000 unit has been built at Baoshan Iron and Steel Corporation, China, and some improvements compared with C2000 have been made. On the basis of material and heat balances, an analysis of material and energy consumption in the Corex C3000 smelting reduction process was conducted and the calculated consumption of lump ore and pellets, coal rate, oxygen consumption are compared with the target values of C3000. Regarding the heat balance calculation, the main factors affecting the energy consumption of C3000 are analysed, and the effective utilization of the sensible heat of top gas and molten slag, as well as the calorific heat of the export gas can be considered to realize lower energy consumption. In addition, the effects of metallization in the reduction shaft and oxidation degree of the gas produced in the melter‐gasifier on the Corex performance are discussed.     

熔融还原流程优化试验研究

介绍了铁矿石在流化床和竖炉模拟装置中的还原试验结果，研究了用不同金属化率预还原矿熔炼的基本能耗，综合讨论了获得最佳还原熔炼配合和最低能耗的熔融还原基本技术参数。     

HIsmelt熔融还原主反应器能质流转模型构建与验证

 HIsmelt熔融还原炼铁工艺以铁矿粉和煤粉作为原料,流程中不需要烧结、球团和焦化,与高炉炼铁流程相比具有降碳减排等优势。明晰能质流转过程对HIsmelt熔融还原炼铁实际生产具有指导意义。基于物料平衡、热平衡方程,对输入和输出HIsmelt主反应器物质和能量进行平衡计算,建立能质流转模型,并结合FactSage中Equilib模块计算的各元素在渣铁两相间的质量分配比及实际生产数据对其进行修正。该模型可以计算原料和燃料成分、矿煤质量比、二次燃烧率、热风氧含量等参数对铁水温度、炉渣成分、热风量、煤气量等主要冶炼指标的影响。其次依据该模型,进行了物料平衡、热平衡计算,依据实际生产数据对模型计算结果进行了验证,结果表明该模型与实际生产数据契合度较高。探究了矿煤质量比对冶炼的影响,矿煤质量比为1.39～1.45时,矿煤质量比降低0.1,会使二次燃烧率降低0.23%,进而造成煤气化学能的利用率降低,同时需要更多的热风使煤粉燃烧,热风量和煤气产生量增加,可以通过适当提高热风氧含量以提高二次燃烧率并使煤气量降低来改善;矿煤质量比降低0.001,会使铁水温度升高3.76 ℃,有利于铁水后续的加工处理,但铁水温度升高使铁元素在铁液与渣中的比值降低,使炉渣FeO质量分数升高0.026%,增加铁损,可通过降低富氧热风喷吹量来降低铁的氧化量,从而降低铁损。     

Smelting‐Reduction Export Gas as Syngas in the Chemical Industry

Export gases from iron‐making processes are typically used as an energy source for heat and power generation within the iron and steel industry, although their calorific value is comparatively low. The fact that COREX® and FINEX® smelting‐reduction export gases typically consist of the major syngas‐components CO and H₂ (approx. 50% of gas composition), makes them attractive for utilization in the direct reduction of iron ores and in the chemical synthesis industry. This paper will discuss the required process steps for converting smelting‐reduction export gases into synthesis gas (syngas) using the example of methanol production. The calculated CO₂‐balance shows promising results for chemical utilization of COREX® export gas compared to energy utilization in conventional or combined power plants.     

Technical analysis on ironmaking process of rotary kiln pre- reduction and smelting by coal and oxygen

The traditional blast furnace ironmaking process has many problems such as long process flow, high dependence on coke and large environmental pollution. In order to solve these problems, the new ironmaking process of rotary kiln pre- reduction and smelting by coal and oxygen was developed. This new process has advantages of wide raw material adaptability, no coke consumption, less pollutant emissions and suitable for special iron ore resources. The mathematical model of the new process was established. Numerical simulation results show that the metallization rate of pre- reduction iron, smelting furnace gas oxidation degree and blast air oxygen content have great influence on coal and oxygen consumption. The coal and oxygen consumption reduces with the increase of pre- reduction iron metallization rate, the rise of oxygen degree of coal gas or the decrease of oxygen content of blast air. This process has a significant advantage in smelting special iron ore resources, which can make up the shortage of blast furnace ironmaking. It is also of great significance to reduce fuel consumption and CO2 emissions.     

二步法熔融还原煤气富氢改质研究

针对高温煤气物理热的有效利用,为预还原工序提供合格的还原气体,提高预还原操作工作效率,更好地匹配二步法熔融还原工艺中预还原和终还原操作,开发了煤气富氢改质模型。利用该模型研究了不同改质条件下进、出改质煤气成分、温度的相互关系。研究表明,煤气富氢改质可有效利用煤气的过剩物理热,节约了二步法熔融还原能量消耗。     

二步法熔融还原煤气富氢改质研究

针对高温煤气物理热的有效利用,为预还原工序提供合格的还原气体,提高预还原操作工作效率,更好地匹配二步法熔融还原工艺中预还原和终还原操作,开发了煤气富氢改质模型。利用该模型研究了不同改质条件下进、出改质煤气成分、温度的相互关系。研究表明,煤气富氢改质可有效利用煤气的过剩物理热,节约了二步法熔融还原能量消耗。     

Experimental Investigation on Optimal Carbon/Hydrogen Ratio for Developing Iron Bath Reactor with H2–C Mixture Reduction

The basic idea of H₂–C mixture reduction reflects advantages of hydrogen for fast reaction and low heat absorption in smelting reduction reactor, where hydrogen is used as main reducing agent and carbon as main heat generator on purpose to cut down total energy consumption and CO₂ emission. This article aimed at the experimental investigation of optimal carbon/hydrogen ratio, a key parameter of iron oxide reduction with mixture reductive agents of carbon and hydrogen. Experiments were carried out using a pure Al₂O₃ crucible which was placed in a tubular furnace for high temperature. Two investigation methods were adopted, one was injecting acetylene/hydrogen mixture reducing gas into molten iron oxides and another was blowing hydrogen into iron bath during continuous feeding fine ore mixing solid carbon dust. Parameters such as apparent de‐oxidation rate and utilization ratio of reductive agents were calculated from content analysis of exhaust gas after dust removing and drying. In experiments highest total de‐oxidation rate and satisfied apparent utilization ratio of hydrogen were obtained under conditions with temperatures of 1823 K and carbon/hydrogen ratio in region from 0.5:1 to 2:1.     

低温冶金技术理论和技术发展

低温冶金通过细化铁矿粉、并运用催化等手段来研究加快铁矿粉在较低反应温度下的还原速度的理论和方法,为开发低能耗、低碳排放、高效的非高炉炼铁新工艺提供理论基础。低温还原理论方面的研究成果,包括细微铁矿粉具有纳米晶粒、储能的铁矿粉能够提高还原气体的利用效率、细粒度改善反应效率、催化剂提高反应速度、改善低温冶金反应的传输条件、多级循环流化床的流化规律以及低温还原冶炼粒铁等理论。在低温还原冶金新技术方面包括改进的熔融还原炼铁工艺、优质海绵铁和粒铁的低温还原工艺。低温还原工艺有望实现节能、低碳、高效和低成本冶金,并能应用于低品位铁矿、含铁冶金渣、赤泥以及钒铁磁铁矿、钛精矿等的综合利用。     

直接还原技术的进展与展望

直接还原是一种以气体、液体燃料或非焦煤为能源,使用球团矿、块矿、粉矿在固态下进行还原生产金属铁的炼铁工艺技术.对国内外直接还原技术的研究情况进行了介绍和评述,表明发展直接还原技术将有较大的市场需求.重点介绍了转底炉法,该技术规模化生产尚未到达成熟的阶段,但具有良好的发展前景.     

Concept and present state of a coal-based smelting reduction process for iron ore fines

The concept of a two-stage smelting reduction process is presented. In the first stage highly metallized iron ore fines are produced in a circulating fluidized bed. In the second stage a hot metal is produced in a melter-gasifier where – together with metallized ore – coal and oxygen are injected to generate the required heat and the CO-rich reducing gas. The process was tested stepwise in pilot scale installations. Although only a reduction temperature of 830 °C instead of the required 880–900 °C could be realized in the pilot unit, test results make it very probable that a metallization of 90% can be reached with any fine ore without sticking problems, if the ore is covered with a carbon layer by CO decomposition in a pretreatment stage with the reduction offgas at 500–600 °C. The CO decomposition on the fresh ore leads to a high gas utilization which renders a CO₂ washing stage and gas recycling unnecessary. To prove the technical and economic feasibility of the combined process, the next development step should be the design and operation of a larger pilot plant with a capacity of at least 5 t hot metal/h for continuous and joint operation of both the melter/gasifier and the reduction stage.     

Direct reduction and smelting reduction – an overview

A survey is given on the current state of direct reduction and smelting reduction processes. Several developments, such as coal injection, top-gas recycling etc., contribute to decrease the coke consumption in the blast furnace. Coal-based as well as gas-based direct reduction processes have not succeeded in Western Europe. These processes have only attracted economical interest in locations where there is a cheap source of energy. Other developments to reduce iron ore are concerned with the direct production of liquid iron in a smelting reduction process with a substantial part of the reduction taking place in the liquid oxide phase. The ideal concept of a smelting reduction process with direct use of fine ore and coal as well as only liquid state reduction to a liquid product similar to steel has not yet been realized.     

Analysis of bath smelting processes for producing iron

A simulation model on bath smelting processes for the production of iron was developed which predicts the coal, flux, ore, and oxygen consumptions and the off gas volume, temperature and composition. The model is comprehensive in that it takes into account all of the important variables including coal composition, metal composition, ore composition, slag basicity, post combustion ratio, (PCR), prereduction degree (PRD), heat transfer coefficient (HTC), flux, scrap charge, and heat losses. Four basic cases were considered: I. 30% PRD–50% PCR; II. 90% PRD–0% PCR; III. 60% PRD–30% PCR; and IV. 0% PRD–50% PCR. Several different coals were considered and a sensitivity analysis of the critical variables was performed. The model also estimates the sulfur content of the metal. The major conclusions are: Post combustion siginificantly reduces coal consumption but above 20% PCR little reduction of FeO to Fe can be performed with the off gas. Prereducing to FeO (case I) and having as much post combustion as consistent with good heat transfer is an attractive process. This process only requires a simple prereducer, uses less coal, and is relatively insensitive to the type of coal used. High off-gas temperatures may pose a potential problem. The off-gas temperature can be reduced by using an O₂–air mixture for post combustion, limiting post combustion or adding water to the gas. The use of CaCO₃ in place of CaO or of supplemental electricity does not appear attractive. The melting unit is theoretically an energy efficient scrap melter. For case I using 200 kg of scrap as part of the charge the coal consumption decreases by about 80 kg. With PCR > 30% the FeO content of the slag is expected to be 2–5%, and the metal will not be saturated with carbon. These factors and the increased sulfur load since coal is the fuel indicate the sulfur content of the metal may exceed 0.25%.     

基于镍铁冶炼工艺流程中物质流和能量流的模型与软件

通过对镍铁冶炼生产工艺中物质流和能量流平衡过程研究,获得了镍铁冶炼工艺中各个环节热量的利用率和损耗情况,以及红土矿、还原剂和熔剂在各部分中反应率,并分析了红土矿和镍铁合金中Ni含量对炉渣中镍铁成分的影响.构建针对镍铁冶炼工艺系统的总体物质流和能量流计算模型,在保证系统总体计算模型的前提下,又具有协同各子工艺系统的物质流和能量流计算模型的功能.依据各子工艺系统中物质流和能量流的关联性,计算烟气和炉气的利用率及热量损失,并利用VB软件对冶炼工艺流程计算软件进行开发.      

两步三段式厚渣层铁浴熔融还原炼铁工艺

针对目前熔融还原设备无法将煤气二次燃烧氧化区与铁氧化物还原区隔离而导致能耗偏高的问题,提出了一种两步三段式厚渣层铁浴熔融还原炼铁工艺,以期利用厚渣层冶炼的方法使得氧化区与还原区的梯度隔离。设计了主反应器铁浴炉尺寸与产能,并建立了工艺的整体静态模型,考察了球团金属化率与铁浴炉炉顶煤气氧化度对工艺煤耗、氧耗以及能耗的影响。在选定的适宜操作参数,即煤气氧化度55%,球团金属化率80%条件下,冶炼1t铁水,消耗球团矿1 869.83kg,煤粉674.07kg,同时得到还原度71%的改质煤气898.44kg。结合反应器的设计产能,反应器可处理球团矿3 793.66kg/(h·m2)。     

高炉生产综合诊控模型研发及应用

 钢铁工业是国民支柱产业,炼铁高炉能耗和成本的高低,在很大程度上决定了一个钢铁联合企业在区域市场的竞争力。从现实条件出发,依靠装备技术进步和信息化手段,通过加强对高炉生产数据的在线跟踪、综合分析及研究,不断优化高炉冶炼标准化、精准化操作模式,合理地处理好具体技术装备、原燃料和高炉4大操作制度的关系,处理好不断上升的煤气流和不断下降的炉料的相关传质、传热关系,为生产管理、技术人员、操作人员寻求合理的高炉操作制度提供依据,成为实现高炉冶炼过程定量化、高效化的一条根本途径。基于炼铁基础理论,通过计算机信息化手段,研发了具有对高炉冶炼过程中煤气流在线诊断、量化评价、优化等功能的生产综合诊控模型并得到应用。通过对高炉冶炼过程中煤气流分布指数、布料矩阵、综合冶炼参数进行适时计算、跟踪及潜力分析,对渣铁成分和指标进行预测预控,得到在具体原燃料条件下高炉进一步挖掘潜力时对布料、送风及渣铁制度等与指标控制相关联复杂相互影响关系数据的量化处理。进而得出满足具体冶炼条件下改善技术指标的冶炼控制措施,并利用物料平衡、热平衡模型对冶炼因素调整进行效果检测。应用结果表明,系列模型的应用有利于形成在具体条件下新的更为匹配的煤气流分布,综合冶炼参数更为和谐,在客观条件改善较小的情况下,喷吹煤粉相对置换比大于1.0,实现了低w(Si)、稳w(Si)冶炼,获得了较高的高炉热量利用率。同比上一年入炉品位条件,实现利用系数、燃料比等指标显著改善。     

高炉使用铁焦的㶲分析

 中国钢铁生产主要以高能耗和高排放的高炉-转炉长流程为主,节能减排压力较大。因此,积极研发高炉低碳炼铁技术,促进高炉工序CO₂减排尤为重要。铁焦是将含铁原料加入适宜的煤中,经焦化或炭化后成型的新型碳铁复合炉料,其高反应性可以显著降低热储备区温度、降低碳消耗,高炉使用适量的铁焦可实现一定程度的节能降碳。基于现场生产数据,采用㶲分析理论,建立高炉使用铁焦的㶲平衡模型,探索铁焦添加量对高炉物料消耗及能量利用效率的影响。结果表明,高炉使用铁焦后,炉内间接还原得到发展,碳利用率提高,炉内灰分量降低,冶炼单位生铁的碳素消耗和炉渣量均会降低,与未使用铁焦相比,高炉使用114 kg铁焦后,吨铁碳素消耗降低25.95 kg,渣量降低11.28 kg。此外,铁焦内部的金属铁仅需熔化,节省还原所需的㶲量,焦炭和鼓风带入㶲会显著降低,因此高炉冶炼吨铁消耗的总㶲量降低,同时,炉内传热也得到改善,内部㶲损失有效降低,与未使用铁焦相比,高炉使用114 kg/t铁焦后,目的㶲效率由46.14%提高至48.87%,热力学完善度由87.46%提高到88.02%。在此条件下,高炉吨铁的内部㶲损失降低192.63 MJ,实现节能6.57 kg(标煤)。     

直接还原炼铁工艺技术综述

直接还原是一种采用天然气、煤气、非焦煤粉作燃料和还原剂，使用球团矿、块矿、粉矿在固态下直接还原生产固体直接还原铁（DRI／HBI）的炼铁工艺技术。全面介绍了各种典型直接还原工艺的原理、特点与缺陷及工业化进展情况，分析了世界直接还原工艺技术发展的动因、现状与趋势。     

煤基直接还原炼铁技术分析

分析了主要的煤基直接还原炼铁工艺。回转窑反应温度低,导致动力学条件变差,停留时间长,散热大,吨铁煤耗达到1000 kg左右。从能量利用角度,过多的煤气还需换热加以利用。隧道窑通过罐装矿粉,可省去造球工艺,但是罐子传热只能通过对流与传导换热方式,因此,停留时间长,热量损失大,同时罐子、海绵铁的余热、废气热量尚未得到利用,导致煤耗高达1 500 kg/t海绵铁。转底炉由于温度高,反应速度快,但是热能利用率差,吨铁实际煤耗居高不下。可见,目前的煤基直接还原炼铁工艺,离低能耗、低污染的炼铁目标相差甚远,最大的问题是固态条件下的还原反应效率过低,提高铁矿的低温反应性能是煤基直接还原炼铁走向成功、高效、环保的关键所在。