基于优化氧化铁皮和焦粉配比的铁矿烧结过程NOx减排研究

Reducing NO_x emission of iron ore sintering process in a cost effective manner is a challenge for the iron and steel industry at present. Effects of the proportion of mill scale and coke breeze on the NO_x emission, strength of sinter, and sinter indexes were studied by combustion and sinter pot tests. Results showed that the peak value of NO concentration, total of NO emission, and fuel-N conversion rate gradually decreased as the proportions of the mill scale increased because NO was reduced to N₂ by Fe₃O₄, FeO, and Fe in the mill scale. The strength of sinter reached the highest value at 8.0wt% mill scale due to the formation of minerals with low melting point. The fuel-N conversion rate slightly fluctuated and total NO_x emission significantly decreased with the decreased proportions of coke breeze because CO formation and content of N element in the sintered mixture decreased. However, the sinter strength also decreased due to the decrease in the amount of the melting minerals. Furthermore, results of the sinter pot tests indicated that NO_x emission decreased. The sinter indexes performed well when the proportions of mill scale and coke breeze were 8.0wt% and 3.70wt% respectively in the sintered mixture.     

NO_x reduction by coupling combustion with recycling flue gas in iron ore sintering process

A new process called’NOx reduction by coupling combustion with recycling flue gas(RCCRF)’was proposed to decrease NOx emission during the iron ore sintering process.The simulation test of NOx reduction was performed over sintered ore and in the process of coke combustion.Experimentally,NOx reduction was also carried out by sintering pot test.For sintered ore,the amount of NOx emission is reduced by 15wt%-25wt% at 400-550oC using 2.0vol% H2 or 2.0vol% CO,or reduced by 10wt%-30wt% at 560-720oC using 0.15vol% NH3.NOx reduction is around 10wt% by coupling combustion of pyrolysis gas and coke,or around 16wt% by recycling flue gas into coke combustion.By RCCRF,the maximum NOx reduction ratio is about 23wt% in coke combustion experiment and over 40wt% in sintering pot test.     

MTPP－CeO_x－SiO_2催化NO_x还原

在密闭循环反应器中，于２９０℃下研究了ＣＯ存在下催化剂ＭＴＰＰ－ＣｅＯ＿ｘ－ＳｉＯ＿２（Ｍ＝Ｃｏ￣（２＋）、Ｎｉ￣（２＋）、Ｃｕ￣（２＋））催化还原ＮＯ或Ｎ＿２Ｏ的反应。催化ＮＯ还原的活性顺序是ＮｉＴＰＰ＞ＣｏＴＰＰ＞ＣｕＴＰＰ，而Ｎ＿２Ｏ还原和ＮＯ深度还原为Ｎ＿２的顺序是ＮｉＴＰＰ＞ＣｕＴＰＰ＞ＣｏＴＰＰ。ＮＯ＿ｘ还原的催化特性和ＭＴＰＰ的电化学氧化机理有关（取决于中心金属或卟啉环被氧化的次序）。ＣＯ不仅还原ＮＯ＿ｘ而且还促进载体Ｃｅ＿２Ｏ＿３物种的形成。探讨了ＮＯ催化还原的机理。     

不同料层高度烧结过程尾气排放规律

研究了不同料层高度下烧结过程中尾气成分(O2、CO2、SO2和NO)的变化规律.结果表明:随着烧结历程的推进,尾气中O2含量降低而CO2含量升高,这主要是因为固体燃料燃烧量逐渐增多;尾气中SO2、NO的含量亦呈升高趋势,但幅度很小,这主要是因为烧结料层对SO2有吸收作用,而燃烧带的CO气体则可以还原使部分NO分解;在临近烧结终点时,因料层对SO2的吸收作用消失而使析出作用强化,导致尾气中SO2含量急剧升高.另外,随着料层高度的增加,因固体燃料配比相应减小,尾气中CO2、SO2和NO的含量降低,而O2含量增加.因此,控制高温区宽度的厚料层烧结技术是我国开展减少烧结尾气中气体污染物(CO2、SO2和NO)的有效措施.     

大型轧钢机架铸造过程数值模拟分析

利用procast软件对大型轧钢机机架铸件的充型、凝固过程中流场和温度场进行了模拟分析,能够较好地预测铸造过程中产生的浇不足、冷隔、夹渣、缩孔缩松等缺陷,为合理优化设计浇注系统,制定最佳工艺方案提供依据。借助procast软件模拟仿真,能够缩短产品试制周期约三个月,降低生产成本约20%,同时能够提高铸件材料利用率,确保铸件质量。仿真结果能够较好地反映实际生产情况。     

氧化铝陶瓷光固化浆料的制备及脱脂工艺优化研究

本文重点研究了光固化浆料固含量和粘度的关系,通过分散剂调控流变学性能,实现了高固含量浆料(45 vol%)的制备并完成打印.在此基础上我们发现,脱脂烧结工艺是决定氧化铝陶瓷成型的另一关键因素.脱脂不彻底会导致气孔、裂纹等缺陷,直接影响到陶瓷质量.鉴于此,本研究针对所制备的氧化铝陶瓷浆料有机物类型,调整了脱脂曲线,并证实通过先在真空中热解后在空气中除碳的两步脱脂方式可使有机物充分去除,不易产生气孔,最终获得了结构致密的氧化铝陶瓷材料.本文系统总结了分散剂种类、浓度及氧化铝固含量对浆料粘度的影响,优化了脱脂工艺,为复杂结构陶瓷材料的光固化成型及性能的优化提供了实验依据.     

基于质量指标的球团焙烧先进过程控制

以某烧结厂球团焙烧过程中燃烧控制系统为研究对象，针对生产过程中因果非线性及条件不确定等因素的影响，综合运用网络技术、软测量技术、模糊控制和专家系统等，提出一种焙烧过程的质量控制策略和先进过程控制(APC)方案，设计了基于神经网络的模糊化软测量(FNNSS)模型。采用软测量的方法实现生产综合条件指标即广义透气性的测定，对不同的透气性采取不同的控制策略，并进行了仿真研究。     

中国温室气体减排与选择性催化还原脱硝材料

综述了中国温室气体排放和Nox污染的现状及相互影响.论述了电厂锅炉和机动车发动机的稀燃化对CO2减排的意义和对Nox污染控制的影响,阐述了选择性催化还原脱硝技术对解决中国经济发展带来的能源危机和温室气体减排的重要性.基于温室气体减排和Nox排放的相互制约关系,指出了采用燃料的稀燃方式辅以SCR脱硝后处理技术是中国同时实现温室气体减排和Nox控制的显示可行途径.重点论述了中国燃煤电厂烟道气脱硝和柴油车尾气脱硝对选择性催化还原(SCR)脱销材料的要求,对国内外脱硝材料的研究领域、研发现状和发展趋势进行了探讨,并结合中国国情指出,具有自主知识产权的V-W-Ti基SCR脱硝材料、低温SCR脱硝材料和沸石基SCR脱硝材料是适应我国电厂烟道气脱硝和机动车尾气脱硝的SCR脱硝材料发展方向.     

Ore-blending optimization model for sintering process based on characteristics of iron ores

An ore-blending optimization model for the sintering process is an intelligent system that includes iron ore characteristics, expert knowledge and material balance. In the present work, 14 indices are proposed to represent chemical composition, granulating properties and high temperature properties of iron ores. After the relationships between iron ore characteristics and sintering performance are established, the "two-step" method and the simplex method are introduced to build the model by distinguishing the calculation of optimized blending proportion of iron ores from that of other sintering materials in order to improve calculation efficiency. The ore-blending optimization model, programmed by Access and Visual Basic, is applied to practical production in steel mills and the results prove that the present model can take advantage of the available iron ore resource with stable sinter yield and quality performance but at a lower cost.     

不同比例半焦与烟煤混合后的燃烧性能

高炉喷煤是钢铁企业降低燃料消耗采取的主要技术措施之一,由于半焦固定碳含量高,可部分替代无烟煤进行喷吹。本文选取了SB半焦、SJ半焦与不同比例的SY无烟煤与HY烟煤进行混合燃烧试验。结果表明,HY烟煤的燃烧性能最佳,使用两种半焦代替SY无烟煤后会在一定程度上降低煤粉的燃烧性能。将25%SB半焦添加比例的混煤在不同升温速率下进行燃烧实验,结果显示升温速率对混煤的燃烧性能影响较大,同比条件下升温速率在40℃/min时,煤的各项燃烧特性参数最优。     

Reduction behavior of hematite in the presence of coke

The reduction kinetics of hematite in the presence of coke as a reductant was studied via isothermal and non-isothermal thermodynamic analyses. The isothermal reduction of hematite was conducted at a pre-determined temperature ranging from 1423 to 1573 K. The results indicated that a higher reduction temperature led to an increased reduction degree and an increased reduction rate. The non-isothermal reduction of hematite was carried out from room temperature to 1573 K at various heating rates from 5 to 15 K·min-1. A greater heating rate gave a greater reduction rate but decreased reduction degree. With an increase in temperature, both the reduction rate and the reduction degree increased at a smaller rate when the temperature was less than 1150 K, and they increased at a higher rate when the temperature was greater than 1150 K before completion of the reduction reaction. Both the isothermal and the non-isothermal reduction behaviors of hematite were described by the Avrami–Erofeev model. For the isothermal reduction, the apparent activation energy and pre-exponential factor were 171.25 kJ·mol-1 and 1.80×105 min-1, respectively. In the case of non-isothermal reduction, however, the apparent activation energy and pre-exponential factor were correlated with the heating rate.     

基于多工况分析的焦炉加热过程火道温度模糊控制

对于焦炉加热这一复杂工业过程,提出一种包括协调层和优化控制层的多工况火道温度优化控制方法.协调层根据对焦炉加热过程工艺参数的分析,采用多信息融合的二次决策方法,由荒煤气的温度识别焦炉加热过程的实时工况,针对不同的工况选择合适的优化控制模型.基于工况分析,在优化控制层采用一种基于自适应遗传算法的多目标模糊优化控制方法,针对不同工况下的模糊控制器量化因子和比例因子调节困难的问题,采用精英保留和赌盘算法相结合的选择策略,以及具有自适应交叉概率和变异概率的遗传算法对模糊优化控制模型的参数寻优,有效地提高了遗传算法的全局搜索能力和收敛速度,并且通过对控制精度、能量消耗和调节时间等各项指标适当加权,构造适应度函数,使优化后的模糊控制模型达到满意程度.采用具有多工况火道温度智能优化控制结构的方法取得了良好的控制效果,为焦炉加热过程的优化控制问题的解决提供了一条新的途径.     

焦炉装平煤过程的离散元模拟优化

目前炼焦煤的供应日趋紧张,在现有设备下提高焦炉的单孔装煤量成为了研究重点。由于物理试验研究不仅耗费劳动力且有很大的不确定性,本文建立了以离散元为基础的仿真模型,研究了焦炉炭化室的装平煤过程。结果表明,由于炭化室结构造成的壁面效应,不同区域的煤料配位数和散密度相差明显,导致了机侧和焦侧缺角严重,装煤不满的现象。针对这个问题,通过改变不同落煤口的装煤顺序,发现在靠近焦侧和机侧的落煤口先落煤时,煤料能够为两侧减少缺角提供支持,从而有效地提高了总装煤量。关于平煤过程,研究确定了一种两次长平煤和两次短平煤相结合的方式,对炭化室内煤料起到了压实、压匀的作用,并明显改善了焦侧缺角的问题。     

支撑板对烧结过程的影响

烧结料层上部荷重是造成烧结过程中燃烧熔融带透气性差的重要因素,而烧结料层透气性是制约我国厚料层烧结技术进一步发展的限制性环节. 从减轻烧结料层燃烧熔融带荷重以及改善烧结过程料层透气性的角度出发,通过在烧结料层中安装支架研究不同荷重条件下对铁矿粉烧结行为的影响. 烧结杯实验研究表明:安装支撑板后,烧结料层透气性明显改善,烧结矿转鼓强度大于65%;垂直烧结速度显著提高,最高可达28. 4 mm·min-1;成品率波动幅度不大,利用系数从1. 89 t· m-2·h-1增加到2. 31 t·m-2 ·h-1;燃耗有所降低,最大降幅达1. 32%. 理论分析和实验表明,支撑板对减轻烧结熔融带上部荷重,提高料层透气性,以及改善燃耗和烧结矿质量具有重要意义.     

高速轧机工作界面非稳态润滑过程界面动力学特性

综合运用轧制理论、流体力学理论、摩擦润滑理论,建立考虑非稳态润滑过程轧机系统力学模型.该模型综合运用界面摩擦模型、轧制力、轧制力矩模型、流体动力润滑模型构成的多重耦合模型,定量分析高速轧机工作界面非稳态润滑过程界面动力学特性.研究结果表明:对于较小的压下率,摩擦应力很小,摩擦应力最大值发生在入口和出口的边缘处,并且在较小的压下率下油膜压应力变化非常小;在较大的张应力条件下,工作区压应力低,油膜剪切应力小,压力梯度也相当小;摩擦应力在入口和出口边缘达到最大;随着张应力的减小,油膜压力增大,剪切应力增大更快,最终达到了润滑油抗剪强度;在全膜润滑或者表面粗糙度很小的情况下,轧制力的平均值和轧制力变化的幅度随着压下率的增加而增加,轧制力的最小值几乎一样,不受表面粗糙度和压下率变化的影响;轧制力矩的变化趋势和轧制力的变化非常相似,然而对于带材表面粗糙度很大的轧制过程,轧制力矩的变化幅度比轧制力的变化小.     

Infiltration behavior of sintering liquid on nuclei ores during low-titanium ore sintering process

Sinter strength is dependent not only on the self-intensity of the residual rude and bonding phase but also on the bonding degree between them. The infiltration behavior of sintering liquid on nuclei ores influences the bonding degree, which ultimately determines the sinter strength. Infiltration tests were conducted using micro-sinter equipment. The infiltration area index of original liquid (IAO), infiltration volume index of secondary liquid (IVS), and sinter body bonding strength (SBS) were proposed to study the melt infiltration behavior. The results show that the IVS first increases and then decreases with increasing TiO₂ content in adhering fines, whereas the IAO exhibits the opposite behavior. Compared with the original liquid, the secondary liquid shows lower porosity, smaller pores, and more uniform distribution. The SBS increases first and then decreases with increasing IAO and TiO₂ content, and reaches a maximum when the IAO and TiO₂ contents are approximately 0.5 and 2.0wt%, respectively. The SBS first increases and then tends to be stable with increasing IVS. The TiO₂ content is suggested to be controlled to approximately 2.0wt% in low-titanium ore sintering.     

冷轧机穿带试验的分析和研究

通过对某钢厂冷轧机穿带试验过程及结果的分析和研究,得出了一些有助于生产实践的结论,进一步证明了新的穿带工艺在此轧机上应用的有效性.     

注凝成型及其烧结工艺研究进展

科技的发展对材料的要求越来越高,传统的成型和烧结技术仅适用于小尺寸且形状规则的金属成型,且需要在一定的压力下才能达到足够高的力学性能。注凝成型技术适用于各种复杂形状、大尺寸部件的近净尺寸成型,具有实验设备简单、工艺过程易控制、坯体密度均匀、强度高等突出优点。为了制备出高固相含量、低黏度、高密度的金属陶瓷,分别从注凝成型工艺过程、注凝成型体系和烧结致密化方法等方面进行了研究。研究表明：注凝成型工艺过程主要分为球磨、凝胶、干燥、排胶和烧结;注凝成型体系分为水系凝胶和非水系凝胶;浆料的黏度对坯体的力学性能影响较大;干燥不当会导致坯体的开裂;烧结温度和烧结助剂对烧结体性能有较大的影响。     

公共交通工具最优组合模型及算法研究

运用电力系统分析中的负荷持续时间曲线和盈亏平衡点理论对公交车辆规模和静态扩张问题进行了分析，建立了数学模型，并给出了相应的算法．     

铁矿石烧结过程传热传质数值模拟

铁矿石烧结是一个复杂的传热传质过程,包括各相之问的传热、水的蒸发与冷凝、碳燃烧、石灰石分解、矿石熔化与凝固以及气相反应等方面.通过对烧结过程进行研究,以多孔介质模型为基础,结合局部非热力学平衡的能量双方程模型、组分传输模型和烧结反应动力学模型,以FLUENT软件为计算平台,采用自定义标量(UDS)构建能量双方程模型,采用自定义功能(UDF)对能量方程、组分传输方程的源项进行修正和定义,建立铁矿石烧结过程传热传质的三维非稳态计算模型.利用该模型对烧结过程进行数值模拟,得到气、固温度以及主要烟气成分的分布,通过与测试值的对比来验证模型的可靠性.