粗煤气铁矿颗粒床高温除尘联产直接还原铁工艺及估算

在煤灰熔点高于直接还原铁还原温度200℃的条件下,以直接还原竖炉作为移动颗粒床除尘器为核心技术的3段连续除尘,以铁矿煤球团为直接还原铁原料和移动颗粒床除尘颗粒,粗煤气显热可以直接用于生产直接还原铁。粗煤气显热约占煤炭气化热值的13%,估算联产直接还原铁显热利用效率可达70%以上,与现有的粗煤气废锅发电比,综合热效率提高约2倍,直接还原铁能耗303kg（C）/t.Fe,可以实现温室气体近零排放,减排CO₂约1.7t/t.Fe。可以在不减少粗煤气化学热能（H₂+CO）,联产直接还原铁的同时解决粗煤气的高温除尘与净化问题。     

直接还原铁生产技术的现状及展望

 分析了世界及中国直接还原铁的技术现状。直接还原工艺可以摆脱焦煤资源短缺的束缚,降低CO2排放,促进资源综合利用,且高品质的直接还原铁是生产洁净钢不可缺少的原材料,是钢铁工业发展不可缺少的组成部分。随着铁矿精选技术、煤制气技术的成熟,从及气基竖炉生产规模的不断增大,煤制气→竖炉将成为中国主要的直接还原生产工艺。高温高料层PSH工艺应当具有良好的应用前景。回转窑、隧道窑等工艺在特定地区可适当发展,但不会成为直接还原铁生产的主流。     

直接还原铁生产概况及发展

介绍了近年国内外直接还原铁生产概况,分析了不同直接还原工艺的状况,认为Midrex是最主要的直接还原铁生产工艺,资源条件决定了煤基回转窑法仍将是我国直接还原铁生产的主要方法,但应重视气基竖炉还原工艺的开发研究工作.我国直接还原铁仍将有较大的市场需求.生产规模过小、工艺设备落后是限制我国直接还原生产发展主要原因.此外,应建立稳定畅通的原料供应渠道.     

直接还原技术进展及其在中国的发展

近年来,全球直接还原铁(DRI/HBI)产量和需求逐年增加,表明直接还原技术是钢铁工业不可缺少的组成部分,有助于炼铁生产摆脱焦煤资源短缺的羁绊,降低钢铁生产能耗,提高钢铁产品质量和品质。气基竖炉生产规模不断增大,成为主要的生产工艺;竖炉直接还原铁热装热送技术的发展进一步降低了工序能耗。回转窑、隧道窑等工艺在特定地区迅速发展,但很难成为直接还原铁生产的主流。我国具备发展直接还原生产的资源条件和技术基础,煤制气—气基竖炉技术是可能的主要发展方向。     

DIRECT REDUCTION OF MIXED MAGNETITE AND COAL PELLETS USING INDUCTION HEATING

A low-temperature process for iron-making, using mixed pellets of magnetite and domestic coal with an organic binder was investigated. Reduction tests performed in an induction furnace resulted in a product direct reduced iron (DRI) containing 75–80% metallic iron. The coal energy consumption of 23.71?GJ/ton DRI compares favorably with current DRI processes, although the total energy consumption of 33.65?GJ/ton is relatively high for iron-making. The use of low-grade coal as a reductant may improve the economics of the process as high-grade coking coal supplies dwindle worldwide.     

电炉炼钢原料及直接还原铁生产技术

中国电炉炼钢的铁源原料由废钢铁料、生铁块、热铁水、直接还原铁等组成。直接还原铁(DRI/HBI)是电炉冶炼纯净钢最佳的残留元素的稀释剂。直接还原是钢铁工业技术发展的重要方向,气基竖炉和煤基回转窑是成熟的直接还原工业化生产技术。中国直接还铁的生产仍处于起步时期,2008年产量约60万t,占世界总产量不足1.0%。直接还原铁在中国有广阔的发展前景,以国内铁矿资源为原料的氧化球团-煤制气-竖炉是中国发展直接还原铁的主要方向。     

钢铁生产环境负荷的累积对比分析评价

根据国内钢铁生产的特点，定义了综合相对环境指数IREI，并在此基础上建立了钢铁生产环境负荷评价的累积对比模型。将该模型应用到国内几种典型的钢铁生产流程评价中，结果表明，评价结果具有可对比性，可以定量化；与高炉－转炉流程相比，直接还原铁的IREI值为0．615，电炉流程吨粗钢的IREI值分别为0．513（特钢），具有较明显的环境优势；此外，以废钢为原料的电炉钢普钢流程的环境负荷也明显小于高炉－转炉流程，其吨粗钢IREI值为0．504。     

Role of Direct Reduced Iron Fines in Nitrogen Removal from Electric Arc Furnace Steel

Electric arc furnace steel contains about 70‐120 ppm nitrogen. There is no suitable method for nitrogen removal from electric arc furnace steel up to the level desired for good quality bars and flat rolled products (30 ppm max). The existing process based on vacuum degassing can remove only up to 20% of nitrogen in steel. In the present study DRI fines have been injected into a steel bath which can drift out nitrogen in steel through production of fine CO bubbles in‐situ on reaction with residual FeO in DRI fines and C in bath. For high and medium carbon steel, nitrogen got reduced to 30 ppm and 60 ppm respectively where initial nitrogen was 150 – 200 ppm in steel. Nitrogen removal also depends upon bath depth and addition level of DRI.     

气基竖炉直接还原技术的发展现状与展望

 阐述了气基竖炉直接还原工艺的技术特点和发展现状,分析了在中国资源和能源条件下气基竖炉直接还原技术发展所面临的主要问题。基于气基竖炉直接还原工艺的特点,对该工艺的原料、还原气等进行了分析研究。指出非常规天然气资源的有效开采和加压煤制气工艺投资、运行成本的显著降低,将是未来气基竖炉直接还原技术发展的主要推动力,同时利用钢铁企业过剩的煤气资源和中国局部地区相对丰富的天然气资源生产直接还原铁,是今后中国气基竖炉直接还原技术发展的重要方向。参照唐山地区的原料和能源价格,对年产量为80万t/a的直接还原铁装置的生产成本和技术经济可行性进行了分析,分析结果表明：原燃料价格波动对DRI成本影响显著,其中还原气成本约占DRI生产成本的10%~25%;若按DRI替代转炉废钢计算效益,要求天然气价格低于1.8元/m3。     

An Approach for Simulation of Corex Process Smelter Gasifier for Prediction of Coal Rate and Silicon in Hot Metal

A thermodynamic model for the Corex process smelter gasifier focusing on coal pyrolysis as well as on the wustite reduction has been proposed. The compositions of hot metal, slag, and the export gas of the Corex process have been simulated satisfactorily for a given degree of metallization of directly reduced iron (DRI). The minimum coal rate is linked to the given degree of prereduction of DRI and the desired final silicon content in the hot metal.     

BL法煤气基竖炉直接还原工艺的开发

宝山钢铁（集团）公司和鲁南化学工业（集团）公司联合开发的ＢＬ直接还原工艺，在世界上首次完成了将德士古煤气化技术用于竖炉直接还原铁的半工业性试验，成功地得到合格海绵铁，试验结果和经济分析表明，这一新工艺具有良好的工业化前景。     

Mathematical Simulation of Burden Distribution in COREX Melter Gasifier by Discrete Element Method

 COREX process is one of the earliest industrialized smelting reduction ironmaking technology. A numerical simulation model based on discrete element method (DEM) has been developed to analyze the burden distribution in the melter gasifier of COREX process. The DEM considering the collisions between particles can directly reproduce the charging process. The burden trajectory, the location and the burden surface profile are analyzed in melter gasifier with a mixing charging of coal and direct reduction iron (DRI) at the same time. Considering the porosity of packed bed has an important effect on the gas flow distribution of melter gasifier, a method to calculate porosity has been proposed. The distribution of DRI and coal and the porosity in the radial direction are given under different charging patterns, which is necessary to judge the gas flow distribution and provide base data for further researching the melter gasifier for the next work in the future. The research results can be used to guide the operation of adjusting charging and provide important basis for optimizing the charging patterns in order to obtain the reasonable gas distribution.     

菱铁矿直接还原-低阶煤提质一体化扩大试验

摘要：菱铁矿作为中国重要的铁矿资源,因具有“贫、细、杂”的特点,常规选矿工艺无法对其进行有效分选;此外,中国低阶煤通常被用作低级燃料直接燃烧使用,导致大气污染严重。因此,开发复杂难选铁矿石及低阶煤资源高效清洁利用新技术,将具有重要现实意义。以难选的低品位菱铁矿和难利用低阶煤为对象,开展菱铁矿直接还原与低阶煤提质一体化扩大试验研究。以神府烟煤为还原剂,在直接还原温度为1050℃,时间为120min,C/Fe质量比为250,脱硫剂配比为6%,干式磁选磁场强度为015 T,一段磨矿细度小于0074mm占50%左右,湿式磁选磁场强度为008 T,二段磨矿细度小于0074mm占90%左右,磁选磁场强度为0043 T的条件下,可获得直接还原铁（DRI）粉铁品位9103%、铁总回收率8133%的良好指标;同时每吨DRI固定碳质量分数为7611%的半焦产品产出率为1340kg,其质量达到工业及民用燃料兰炭Ⅰ级品标准。在煤基直接还原工艺中一步成功实现低阶煤半焦化提质和铁矿直接还原,不仅可制备电炉炼钢原料,还可以生产新型的清洁燃料半焦。     

一种新型优质电炉炉料

对粒铁脱碳机理进行了分析,并对粒铁脱碳工艺流程和脱碳粒铁进行了技术评价。结果表明,在脱碳粒铁质量、建设投资、生产成本、生产规模可变性、操作难易程度、生产效率和对原材料的要求等方面,粒铁脱碳技术都比用直接还原法生产海绵铁或用其它途径更为合理和容易实现。脱碳粒铁可作为电炉的常规炉料,而且是一种可代替海绵铁和重废钢的纯净优质炉料。     

中国发展非高炉炼铁的现状及展望

非高炉炼铁是钢铁工业发展的前沿技术之一。目前,直接还原已成为世界钢铁工业不可缺少的组成部分。熔融还原虽实现工业化生产的环境优越性得以公认,但其低能耗、低成本等优点还有待于实践证实。发展直接还原铁生产弥补废钢的短缺是中国钢铁工业、装备制造业发展的急需。以国内技术为基础,利用国内铁矿资源,以煤制气 竖炉为主导工艺是中国发展直接还原铁生产的主要方向。加强对国外熔融还原技术发展的跟踪,强化国内熔融还原技术的开发力度,尤其是消化COREX技术以及实现其装备的国产化是中国熔融还原发展的重要方向。     

回转窑一步法直接还原铁生产的试验研究

以新疆磁铁精矿为原料,采用一步法直接还原,研究高强度、高还原性预热球团的制备及煤基直接还原的工艺.研究了实验室转鼓模拟回转窑装置中直接还原铁的生产工艺.讨论了配碳比、反应温度、反应时间等工艺参数对金属化率、脱硫率等回转窑直接还原铁的主要质量指标的影响,提出了本试验原料条件下,回转窑生产直接还原铁的最佳工艺参数.研究结果...     

Nitrogen in SL/RN direct reduced iron: origin and effect on nitrogen control in EAF steelmaking

Abstract

In the steel plant considered here, direct reduced iron (DRI), produced by the coal based Stelco–Lurgi/Republic–National (SL/RN) process, makes up 50% or more of the total iron charge. The SL/RN DRI samples from a kiln cooler had high nitrogen contents (50–250 ppm, depending on particle size), contributing to elevated nitrogen levels in liquid steel produced in the electric arc furnaces. The proposed mechanism of nitriding of SL/RN DRI involves gaseous nitrogen (present within the rotary cooler) diffusing into the solid bed and is supported by a simple diffusion model. A strong correlation was found between the melt-in carbon content of the liquid steel and the final tap nitrogen content, with melt-in carbon of 0·3%C or higher resulting in nitrogen levels below 50 ppm at tap, even when charging DRI material that is high in nitrogen.     

Cost and Life Cycle Analysis for Deep CO2 Emissions Reduction for Steel Making: Direct Reduced Iron Technologies

Among heavy industrial sectors worldwide, the steel industry ranks first in carbon dioxide (CO₂) emissions. Technologies that produce direct reduced iron (DRI) enable the industry to reduce emissions or even approach net-zero CO₂ emissions for steel production. Herein, comprehensive cradle-to-gate (CTG) life cycle analysis (LCA) and techno-economic analysis (TEA) are used to evaluate the CO₂ emissions of three DRI technologies. Compared to the baseline of blast furnace and basic oxygen furnace (BF–BOF) technology for steel making, using natural gas (NG) to produce DRI has the potential to reduce CTG CO₂ emissions by 33%. When 83% or 100% renewable H₂ is used for DRI production, DRI technologies can potentially reduce CO₂ emissions by 57% and 67%, respectively, compared to baseline BF–BOF technology. However, the renewable H₂ application for DRI increases the levelized cost of steel (LCOS). When renewable natural gas (RNG) and clean electricity are used for steel production, the CTG CO₂ emissions of all the DRI technologies can potentially be reduced by more than 90% compared to the baseline BF–BOF technology, although the LCOS depends largely on the cost of RNG and clean electricity.     

直接还原铁生产工艺的选择

论述了直接还原铁生产工艺的发展,介绍了目前世界直接还原铁生产工艺的现状、特点.指出,钢铁联合企业的可持续发展需要直接还原铁,高炉、直接还原炉、焦炉联合流程是其生产直接还原铁的最佳工艺选择.     

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。