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COREX流程主要使用块煤作为燃料,但仍需要加入一定比例的焦炭来支撑熔融气化炉内炉料,保证炉况顺行.块煤裂解形成的半焦和焦炭在熔融气化炉内的劣化程度对煤气流的透气性、渣铁的透气透液性和炉缸热量的分布等影响较大.利用风口取样技术取出风口焦试样,进行粒度分布研究、显微结构分析、透气性指数计算和热态性能测定,发现风口焦试样中大于10mm的较大颗粒多为入炉焦炭劣化所致,小于10mm的小颗粒多为块煤裂解所致;认为块煤挥发分热解后的产物会加剧焦炭的溶损反应,且块煤裂解半焦的反应后强度不及入炉焦炭,半焦在炉内的劣化是影响渣铁透气透液性的主要因素;最后结合对试验结果的分析,给出了降低COREX流程能耗的一些措施. 相似文献
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采用200 kg级炼焦炉对熔融气化炉主要使用的2种块煤进行了不同时间的半焦裂解试验,比较了2种块煤成焦后的粒度分布和强度变化,发现B煤在炼焦炉内粉化严重,随结焦时间的延长其粒度降解度一直在升高,而A煤降解度在达到最大值后开始下降.对比了2种块煤生成半焦的矿相微观结构,A煤生成的半焦主要以镶嵌结构和各向同性结构为主,而B煤生成的半焦主要以类丝炭和各向同性结构为主;2种半焦均含有未成焦煤.通过分析熔融气化炉内取出的风口试样中不同粒度的含碳物质其矿相微观结构,认为在炉缸内6.3 mm的颗粒由2种块煤裂解成焦后的粉化现象所引起,且B煤的粉化是主要因素. 相似文献
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相比于高炉风口喷吹富氧热风,熔融气化炉风口采用常温纯氧,使得炉内质量、动量、热量的传输以及煤气流分布等冶炼特征与高炉存在较大差异.通过建立熔融气化炉风口回旋区二维数学模型,系统考察熔融气化炉风口回旋区内速度分布、温度分布及气体组分分布的冶炼特征.结果表明:在气固相热交换及焦炭 (或块煤形成的半焦) 燃烧反应的综合作用下,熔融气化炉风口回旋区内气体温度迅速升高至3 500 K以上;此外,风口前端存在小规模的气体循环流动现象,故风口前端扩孔破损现象严重,进而导致非计划休风率较高;为减少此类休风现象,可适当额外喷吹富氢燃料性气体 (天然气、焦炉煤气),不仅能降低风口回旋区内气体温度,更可替代部分固体燃料,并充分发挥其中H2的高温还原优势,提升熔融气化炉冶炼效率. 相似文献
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为了研究块煤在熔融气化炉内高温结构演变和降解机制,采用扫描电镜和光学显微镜观察了COREX熔融气化炉风口焦和实验室自制半焦的形貌和显微结构,并结合不同试样的高温反应特性,确定了不同风口焦试样的来源。结果表明,风口焦中兴隆庄块煤形成试样含有较多的中粒和粗粒镶嵌结构,表面呈孔状结构;大同块煤形成试样中类丝炭较多,表面呈层状结构。根据结果提出应考虑灰分对煤焦高温强度的影响,在测量风口焦试样的反应性及反应后强度时应考虑灰分含量进行折算,并确定了以灰分的基准含量为13%进行折算为最佳条件。 相似文献
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《有色金属科学与工程》2017,(6)
熔融气化炉填充床是将预还原炉料熔炼为液态铁水,并利用块煤裂解生成大量还原煤气供预还原竖炉使用的主要冶炼场所.文章建立了熔融气化炉填充床一维稳态数学模型,数值模拟分析了填充床内还原煤气与固体炉料的温度及组分分布特征.结果表明:由于海绵铁与块煤及熔剂的温差较大,固相间辐射热传递使得海绵铁温度呈先降低后升高的变化趋势,随着固体炉料的下降,海绵铁逐渐熔炼为液态铁水,至填充床底部,铁水温度可达1 774 K.另一方面,随着煤气流的上升,块煤热解使得H_2体积浓度大幅提高,熔剂分解及海绵铁还原亦导致CO_2体积浓度逐渐增大,至填充床上部,CO体积浓度稳定于71.8%. 相似文献
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高炉直吹管内煤粉燃烧是在有限空间内进行的,煤粉的燃烧受到限制。为了促进直吹管内煤粉的燃烧,通过二维模型研究了不同的煤粉性能和高炉操作条件对双枪喷煤时直吹管内煤粉燃烧率的影响。结果表明。煤粉的粒度越小,煤粉的燃烬率越高;煤粉的挥发分质量分数越高、热风的氧气质量分数越高,煤粉的燃烬率也越高。较高的热风温度有利于煤粉的燃烧.但当热风温度提高到1 200℃以上时,继续提高热风温度对煤粉燃烬率的影响较小。此外,还对直吹管内挥发分、温度以及各种气体成分的分布情况进行了对比分析,以便更好地理解上述操作条件对煤粉燃烧的影响。 相似文献
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《钢铁研究学报(英文版)》2015,(12)
Fuel consumption in the COREX-3000 process run in Baosteel is currently higher than the design index.Therefore,mass and heat balance equations for the COREX process were established using the basic principles included in the Rist operating diagram for blast furnace(BF)as a reference.Thermodynamic calculations were then used to modify the Rist operating diagram so that it was suitable for the COREX process.The modified Rist operating diagram was then applied for the evaluation of metallization rate(MR)and fuel structure to reduce the energy consumption in the COREX process.The modified Rist operating diagram for the shaft furnace(SF)provided a nearly ideal value for the restriction point W when the metallization rate was increased,while the point Pon the operating line for the melter gasifier(MG)moved upward due to reduction in the heat required in hearth.The feasibility of reducing the energy consumption during the COREX process by changing the fuel structure was also demonstrated. 相似文献
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Yanling Guo Wanren Xu Jinming Zhu Jieyu Zhang 《Metallurgical and Materials Transactions B》2013,44(5):1078-1085
A major advancement in the Corex ironmaking process is the usage of lump coal considering the shortage of coking coal resources worldwide. However, the burden similar to that of the blast furnace is still essential for the enlarged melter gasifier. The notable difference is that the burden of the melter gasifier is composed of char formed from lump coal with a small amount of coke. The burden structure of the melter gasifier was investigated by the tuyere probing while the plant was shut down at different operating conditions. The specimens representing the different positions of lump zone, cohesive zone, and dripping zone were analyzed by means of coke/char size distribution and X-ray diffraction (XRD) for the degree of graphitization of coke. A chemical analysis of metal composition has also been performed to get a better understanding of the final reduction in the melter gasifier. The burden structure is supposed to be divided into three zones: active zone, outer of deadman, and deadman core, where coke/char was consumed differently. Based on these analyses, some technical advice to improve the Corex operation is given. 相似文献
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HAN Li-hao LUO Zhi-guo ZHOU Xiao-lei ZHOU Heng ZOU Zong-shu ZHANG Yu-zhu 《钢铁研究学报(英文版)》2013,20(3):30-35
The temperature distribution of COREX melter gasifier was studied by using a two-dimensional 1/30 scale thermal dynamic model. A set of operating conditions, such as radial distribution of direct reduction iron (DRI) to lump coal and coke volume ratio, coke charging location, coke charging amount and coke size, were taken into account. The results show that the temperature near the wall region decreases with the decrease of the radial distribution of DRI to lump coal and coke volume ratio. The temperature with central coke charging is higher than that without central coke column. Furthermore, the temperature significantly increases with the increase of central coke charging amount. With the increase of intermediate coke charging amount, the temperature near the wall region decreases while the temperature in the intermediate region increases. The temperature increases with the increase of coke size whether charging central coke or intermediate coke. 相似文献
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装料模式决定了料床的孔隙度结构,进而决定了煤气流的分布信息。建立了气化炉炉料结构的离散单元模型和煤气流动的多孔介质模型,以自编程和软件Fluent为载体,结合两个模型共同描述了不同加焦方式对气化炉的炉料结构和煤气流动带来的变化,获得了炉内炉料结构的孔隙度分布信息和煤气的速度场、流线和质量通量。结果表明:首先,由离散单元模型获得的炉料结构信息可作为气流分布模型的边界条件输入;其次,煤气流模型的模拟结果表明焦柱的加入会在加焦位置处形成煤气发展通路,进而改善气化炉透气性,但应控制焦炭加入量,避免气流过度发展,进而影响煤气利用率。通过模拟计算获得的非均匀床层气体流动规律的认识对气化炉加焦工艺有借鉴意义。 相似文献
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布料模式决定了料床的空隙度,而料床的空隙度分布决定了煤气流的二次分布.本文建立了研究三维气化炉炉料结构和煤气流分布的物理模型和数学模型,物理模型采用热电偶测温的方法,从炉内气体温度分布信息考察了气体的流动情况,由于物理实验无法获得内部空隙度分布信息,故基于离散单元法模型,以Fluent软件为载体,利用多孔介质模型并加入用户自定义函数,通过数学模型进一步研究了不同加焦方式下气化炉内煤气流分布的影响机理,获得了气化炉内煤气的速度场和流线.物理模拟与数值模拟结果相吻合.通过模拟计算获得的非均匀床层内气体流动规律的认识对COREX气化炉加焦工艺有借鉴意义. 相似文献
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以国内某大型高炉为研究对象,以挖潜降耗为主要目标,利用计算Rist操作线的方法,根据实际生产数据,绘制出实际的和理想的Rist操作线图。并在此基础上,定量计算出该大型高炉降低焦比的潜能以及煤气中CO_2质量分数对于焦比的影响等。根据该大型高炉实际生产情况,采取优化装料制度,改善煤气流分布,将单纯发展中心气流改进为以中心气流为主,兼顾边缘气流的思想,从而提高煤气利用率2%,降低焦比13kg/t,但还有进一步挖潜降耗的空间。 相似文献