炉顶煤气循环氧气高炉的能耗和碳排放

基于相间传热传质和反应动力学理论,建立了由高炉本体一维模型、风口回旋区燃烧模型、CO2脱除单元模型和煤气预热单元模型组成的炉顶煤气循环氧气高炉工艺综合模型,研究了该新型炼铁工艺的可行性,分析了关键参数对综合能耗和碳排放的影响。研究结果表明:下排风口循环煤气流量需要维持在一定范围内来保持合理的理论燃烧温度;低温和高还原势的炉内环境有利于抑制焦炭气化反应,加强铁氧化物间接还原;氧气高炉的煤气输出量较少,但热值很高,能达到传统高炉煤气热值的2倍以上;焦炭消耗的减少显著降低了氧气高炉的输入总能量,即便是与副产煤气全部有效利用的传统高炉相比,氧气高炉仍具有综合能耗较低的优势;由于氧气鼓风和CO2分离过程消耗大量电力,氧气高炉的CO2间接排放要高于传统高炉,而CO2捕集和封存可显著降低氧气高炉系统的CO2直接排放;与传统高炉相比,氧气高炉系统的CO2直接排放可降低57.1%~59.0%,净排放可降低32.9%~40.4%,节碳减排效果显著。     

氧气高炉喷吹焦炉煤气数学模型

 为降低氧气高炉炼铁流程中循环煤气脱除CO2及煤气预热成本,提出了氧气高炉喷吹焦炉煤气炼铁流程,并建立了新流程能质平衡数学模型,应用该模型分别对传统高炉、传统高炉喷吹焦炉煤气、氧气高炉（鼓风氧体积分数为30%、40%、50%、100%）喷吹焦炉煤气炼铁流程主要技术参数进行计算并对比。结果表明,传统高炉喷吹少量焦炉煤气（30 m3/t）可降低燃料比13 kg/t,焦炉煤气置换焦炭的置换比为0.433 kg/m3,但是对其他参数影响不大。氧气高炉喷吹焦炉煤气流程随着富氧率提高,炉内还原势提高,CO和氢利用率下降,炉内存在还原剂表观过剩,非全氧鼓风条件下炉内没有发生氮气富集。新流程外供煤气总热值为3 000 MJ/t左右,与传统高炉相比变化不大,对现有钢铁联合企业煤气供需平衡影响较小。全氧高炉喷吹焦炉煤气炼铁流程相较于目前的高炉炼铁流程可节焦43%,增煤33%,总燃料比降低20%。     

喷吹煤造气炉工艺参数的研究

为了使高炉生产更加高效、节能环保,提出了高炉喷煤新工艺,将造气炉内煤气化生产富氢煤气代替高炉喷煤。采用二硅化钼高温炉对不同工艺参数(温度、时间、压力、气化剂流量)下煤的气化进行实验,用红外线气体分析仪分析产出煤气的气体成分。结果表明:随着温度的增加,煤气中CO含量升高,H_2含量逐渐降低,还原气体组分(CO+H_2)含量增加的速率逐渐变缓;煤气中的还原气体组分含量随着反应时间的增加先增加后减少;随着压力的增加,煤气中CO和H_2的含量先增加,继续加压,煤气中的CO含量逐渐平稳且有下降的趋势,H_2含量的上升逐渐变缓,煤气中的还原气体组分含量升高的速率逐渐变慢;随着气化剂流量的增加,煤气中还原气体组分含量先升高后降低,H_2和CO含量均呈现先升高后降低的趋势。当反应温度为1000℃,反应时间为5min,气化剂流量为10L/min,煤气出口压力为0. 5kPa时,造气炉最佳煤气产出成分CO和H_2分别为49. 05%和18. 75%。     

高炉喷吹改质焦炉煤气减少CO2排放的技术发展

在日本,自2008年起开始推进COURSE50项目,该项目隶属于国际钢铁协会的CO2减排计划的子项目,旨在通过创新技术在炼钢工艺中减少CO2的排放。这项计划通过氢气还原铁矿石,以及CO2捕获分离和回收等措施开发减少CO2排放的技术。计划中的一项关键技术是,通过改质的焦炉煤气,利用氢气还原技术来降低高炉中碳的消耗。通过软熔测试装置进行了还原试验来论证炉身喷吹的条件。结果表明,在炉身喷吹改质焦炉煤气能有效改善炉墙区域的透气性,喷吹的高氢含量改质焦炉煤气可增加间接还原度。得到了改质焦炉煤气的理想喷吹条件:改质焦炉煤气的喷吹量应控制在200Nm3/t以上,同时喷吹煤气的比例达到20%以上。建立了高炉炉身喷吹改质焦炉煤气的气固两相流冷态模型,以分析高炉内的煤气流分布。对炉内煤气流量、流速对气流分布的影响进行了研究。结果表明,从炉墙向内可穿透的最大距离为炉身半径的15%～20%。该结果表明,通过在炉身喷吹改质焦炉煤气来减少高炉碳消耗的可能性较大,由于利用氢还原比利用CO还原具有更高的反应效率,进而减少炼铁工艺的CO2排放。     

高还原势气氛下球团矿还原行为的研究

炉顶煤气循环氧气高炉采用纯氧鼓风以及炉顶煤气循环利用工艺使得炉内煤气成分与传统高炉相比发生了改变,炉内的煤气成分主要以H2和CO为主.为了研究还原性气体H2和CO对球团矿还原行为的影响,分别用H2-N2、CO-N2、H2-CO混合气体在1173K下通过热重的方法进行试验.研究发现还原度随着混合气体中H2或CO比例的增加而增加,但是H2的还原能力明显比CO要强.在H2-CO混合气体中H2的加入有利于还原进行.用H2-CO混合气体还原得到的还原速率不能用H2-N2和CO-N2混合气体下得到的还原速率相加得到.微观结构观察发现,用H2进行还原时得到的铁结构较致密,而用CO还原时铁会破裂为许多小碎片.在用含一氧化碳的混合气体进行还原时,还原度曲线在还原后期由于碳沉积导致出现下降的趋势.还原气体中氢气的存在会加剧碳沉积现象,而氮气的存在会抑制这一现象.对还原后试样进行X射线衍射以及化学分析表明试样中的碳以碳化铁(Fe3C)和石墨形式存在.     

喷吹循环煤气氧气高炉的静态模型

根据整体及各区域的物理化学约束条件建立了氧气高炉工艺综合数学模型.通过模型的计算结果对能量在不同区域的利用情况进行了分析.得出结论如下:氧气高炉无煤气循环流程的一次能耗很高,燃料比在600 kg/tHM以上,并且无法实现高温区和固体炉料区之间的能量匹配.炉顶煤气循环后,可以实现能量在高温区和固体炉料区的同时平衡;在同时满足全炉热平衡和区域热平衡的条件下,氧气高炉炉身喷吹循环煤气流程的理论燃烧温度过高,而炉缸喷吹循环煤气流程的理论燃烧温度偏低;对于氧气高炉炉身、炉缸同时喷吹循环煤气流程,随着循环煤气量的增大,焦比升高,煤比降低,理论燃烧温度可以维持在合理的范围内.     

氧气高炉喷吹气化炉重整煤气工艺的?分析

为降低氧气高炉炼铁工艺流程中循环煤气分离和煤气预热成本, 提出氧气高炉喷吹气化炉重整煤气炼铁工艺流程.采用?分析方法对该工艺过程和传统高炉炼铁工艺过程的主要?指数进行计算和评价分析, 结果表明:在传统高炉工艺中, 高炉单元和整体系统的?损失（指每吨铁水,下同）分别为0.911 GJ/t和1.636 GJ/t;在氧气高炉喷吹气化炉重整煤气工艺中, 高炉单元和整体系统的?损失分别为0.298 GJ/t和0.826 GJ/t; 另外, 传统高炉和氧气高炉喷吹气化炉重整煤气工艺系统的?效率分别为83 %和91 %.该工艺能够实现冶金和化工行业的联合生产, 对于促进工业联产具有重要意义.      

高炉喷吹COREX脱CO2顶煤气的数值分析

 COREX脱CO₂顶煤气作为一种优质富氢气体,直接喷吹进入高炉可有效降低高炉燃料消耗。建立了高炉喷吹COREX脱CO₂顶煤气静态工艺模型,研究高炉喷气对风口理论燃烧温度、炉腹煤气量、炉腹煤气成分、风口回旋区形状、直接还原度、节焦效果等因素的影响,并进一步探究了提高风温作为热补偿措施后的适宜喷气量。研究结果表明,不采取热补偿措施条件下,随着COREX脱CO₂顶煤气喷吹量的增加,理论燃烧温度逐渐降低,炉腹煤气量逐渐升高,高炉直接还原度降低。以维持理论燃烧温度和炉腹煤气量稳定为标准,风温相对基准提高30、60、90 ℃后,可接受喷吹的煤气量为45.4、85.5、123.3 m3/t。热补偿后,随着喷气量增加,鼓风量逐渐降低,富氧率逐渐升高。炉腹煤气中的CO及H₂含量随喷气量增加而增加,每增加10 m3/t的COREX煤气喷吹量,炉腹煤气中总的还原气体体积分数增加0.46 %,直接还原度降低0.006,节约焦炭1.48 kg/t。     

工艺参数对氧气高炉能耗的影响规律

建立了氧气高炉煤气不循环利用流程,炉身喷吹循环煤气流程和炉缸喷吹循环煤气流程数学模型,分析了工艺参数对氧气高炉能耗的影响,结果表明：煤气不循环利用流程一次能耗远远高于煤气循环利用流程,不适合进行工业化生产;金属化率对氧气高炉能耗影响很大,金属化率每升高5％,吨铁焦比降低约37kg;煤气循环利用流程各煤气量匹配要合理,炉...     

CO2炼钢对氧气高炉循环煤气的改质及加热

 为解决氧气高炉循环煤气CO2脱除和加热过程中的析碳问题,提出了一种利用CO2炼钢对煤气进行改质和加热的方法,并通过热力学计算探讨了铁水和煤气成分对炼钢过程的影响,得到了合理的循环煤气处理方案。结果表明,CO2炼钢反应总体上是大量吸热的,需要外部热源提供热量;以氧气高炉炉顶煤气为氧化剂时,炼钢温度范围内铁水中碳的脱除限度在0.02%以下,脱除率高于99%;煤气处理能力和改质煤气成分受铁水成分影响,并且铁水中碳含量的影响更大;通过CO2炼钢与变压吸附2种工艺的结合,可满足氧气高炉对循环煤气量和温度的需求。     

鼓风参数对炉顶煤气循环高炉的影响分析

针对炉顶煤气循环高炉(TGRBF)的工艺特点,建立了此工艺的数学模型,根据模型的计算流程和给定的条件数据,计算出了一种给定条件下TGRBF的基本工艺参数,焦比180kg/t,煤比200kg/t,直接还原度为0.15;通过调整设定的鼓风温度和鼓风中的氧气含量,得出这2个参数变化对焦比、循环煤气量、鼓风量、炉顶煤气中CO含量、风口焦炭燃烧比例、循环煤气的富余量等参数的影响。     

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.     

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.     

Numerical Simulation of Innovative Operation of Blast Furnace Based on Multi-Fluid Model

To date ,blast furnace operators have a relative-ly good understanding of internal mechanisms ,andno longer treat blast furnace as a“black box”. Forthe blast furnace , however , one of the most com-plex metallurgical units inthe field of chemical engi-neering,the complexity keeps proliferating with theadoption of newtechnologies ,such as high rate in-jection of pulverized coal ,effective use of carbona-ceous andferrous materials ,and so on.If merely bydirect instrumentation and empirical kno…     

高炉喷吹还原气操作的数学模拟研究

副产煤气的高效利用对钢铁产业的节能降耗和环境保护意义重大。为此,提出了一个新的高炉风口喷吹高炉、转炉和焦炉煤气技术,并利用多流体高炉模型对其进行了详细模拟研究,预测了炉内现象和操作性能的变化。在维持回旋区温度、炉腹煤气量及渣面处铁水温度一致的条件下,模拟结果表明与现行常规操作相比,风口喷吹煤气后炉身温度下降,但整个炉内H₂/CO浓度显著提高,炉身烧结矿间接还原加速,产量明显增加,热利用效率明显改善。其中喷吹焦炉煤气效果最为显著,高炉CO₂产生量大幅度降低。随工艺氧制备等技术的进步,高炉喷吹副产煤气技术具有广阔的应用前景。     

结合CCS的炉顶煤气循环—氧气鼓风高炉CO2减排分析

 介绍了炉顶煤气循环—氧气鼓风高炉炼铁技术的研发进展,阐述了碳捕捉及封存技术(CCS)的特点及其技术成熟度,重点分析了几种CO2分离方法的原理及其适用条件,最后应用IPCC2006方法计算分析了结合碳捕捉及封存技术的炉顶煤气循环氧气鼓风高炉的CO2减排效果。结果表明：新工艺的吨铁CO2排放量为582.40kg,较传统高炉CO2减排55%。结合碳捕捉及封存技术的炉顶煤气循环氧气鼓风高炉炼铁技术的开发,能够促进中国钢铁工业CO2减排,对钢铁工业的可持续发展具有十分重要的现实意义和深远影响。     

���ڹ��̼��㷨�ĸ�¯���۽��ȼ���ģ��

A theoretical coke rate calculation model was established based on the traditional engineering method with the consideration of the combustion of pulverized coal, oxygen enrichment, blast humidity and other factors. A coefficient, measuring the amount of heat load with the change of furnace carbon, is proposed to establish the calculation method of heat loss. The theoretical coke rate and appropriate direct reduction rate of some large- scale blast furnace are calculated based on this model. Then the effects of different factors, including blast temperature, blast humidity, top temperature, iron ore grade, ash content and sulfur content of coke, carbonate flux consumption, silicon content of hot metal, direct reduction rate and slag rate, on coke rate were analyzed. The results show that the theoretical coke rate is 277. 15kg/t and appropriate direct reduction rate is 0. 34. The iron ore grade, ash content of coke, silicon content of hot metal and direct reduction rate have significant influences on coke rate. In addition, the calculation values in this model are lower than those of traditional model, which means the degrees of the factors affecting coke rate decrease nowadays.     

Numerical Evaluation of Blast Furnace Performance under Top Gas Recycling and Lower Temperature Operation

The new process of top gas recycling by hot reducing gas (HRG) injection has been developed in this study in order to overcome the disadvantageous problems under the lower temperature operation, to enhance the utilization of top gas carbon and to reduce carbon dioxide emission of blast furnaces. Numerical evaluation of blast furnace top gas recirculation together with lower‐temperature operation was performed by means of a multi‐fluid blast furnace model. The simulation results show that, (1) under the lower temperature operation, the shaft injection, or simultaneous shaft and tuyere injection of hot reducing gas is effective to increase the heat supply and to enrich the reduction atmosphere in the shaft zone, to improve the reduction of iron burdens, and enhance the efficiency of the shaft zone. (2) If top gas is recirculated by HRG on the basis of lower temperature operation, a highly efficient low‐carbon blast furnace is obtained. The productivity of the furnace shows a remarkable increase and the total reducing agent rate shows a considerable decrease. Furthermore, the top gas carbon utilization is enhanced and the carbon dioxide emission rate is lowered. (3) Generally, shaft efficiency, carbon emission and heat efficiency under simultaneous tuyere and shaft injection are comparatively better than in the other two methods of single injection.     

全氧混合喷吹煤粉和富氢燃料高炉新工艺的可行性

 提出了全氧混合喷吹煤粉和富氢燃气高炉炼铁新工艺,并通过理论分析结合实验证明新工艺的可行性。理论计算证明,在新工艺条件下,理论燃烧温度控制在1 800~1 850 ℃时可同时满足高炉上下部热平衡;实验结果证明,在焦炭气化反应激烈开始温度前,铁矿石金属化率可达95%,焦炭在高炉内参与直接还原而气化程度很低,吨铁焦比可降到190 kg。煤气氮含量低于07%,有利于CO2回收,可实现CO2零排放。煤气热值达到8 200 kJ/m3。这种煤气不仅适合钢铁联合企业和传统燃气用户使用,也可直接用于高效的电 热 冷三联产系统,间接实现了燃煤高效洁净化利用。     

Numerical Analysis of Blast Furnace Performance Under Charging Iron-Bearing Burdens With High Reducibility

The reducibility of iron-bearing burdens was emphasized for improving the operation efficiency of blast furnace. The blast furnace operation of charging the burdens with high reducibility has been numerically evaluated using a multi-fluid blast furnace model. The effects of reaction rate constants and diffusion coefficients were investigated separately or simultaneously for clarifying the variations of furnace state. According to the model simulation results, in the upper zone, the indirect reduction of the burdens proceeds at a faster rate and the shaft efficiency is enhanced with the improvement under the conditions of interface reaction and intra-particle diffusion. In the lower zone, direct reduction in molten slag is restrained. As a consequence, CO utilization of top gas is enhanced and the ratio of direct reduction is decreased. It is possible to achieve higher energy efficiency of the blast furnace, and this is represented by the improvement in productivity and the decrease in consumption of reducing agent. The use of high-reducibility burdens contributes to a better performance of blast furnace. More efforts are necessary to develop and apply high-reducibility sinter and carbon composite agglomerates for practical application at a blast furnace.