全氧条件下高炉高温热化学反应与能质传递协同原理

The Synergistic Principle of Energy/mass Transfer and High Temperature Thermochemical Reaction Under Full Oxygen Blast Furnace Condition

高炉作为目前主要的炼铁工艺,经过上百年的发展,其碳耗已接近该工艺的理论最低值,很难再有大的突破。氧气高炉作为一种新型炼铁工艺,其可行性以及在节碳减排方面的突出优势已经在理论上和试验性高炉上得到了证实。该工艺由于采用全氧鼓风代替传统的热风操作,同时将炉顶煤气脱除CO2后循环回高炉,使得炉内煤气中的CO和H2含量大幅增加,从而导致炉内炉料的冶金性能也发生了变化。为了推进氧气高炉工艺的工业化应用,对氧气高炉炼铁工艺进行了系统的研究。该研究建立了一种氧气高炉综合数学模型,对不同氧气高炉工艺流程进行模拟计算,并采用多种评价指标对氧气高炉炼铁工艺进行综合评价,确定适宜的氧气高炉工艺流程,为研究开发氧气高炉炼铁工艺提供理论基础。以氧气高炉数学模型为基础,在不同气氛下分别进行烧结矿、球团矿和块矿的低温还原粉化实验,分析氧气高炉气氛下含铁炉料的低温还原粉化特性。利用高温还原熔滴实验装置,进行不同操作条件下(传统高炉和氧气高炉)含铁炉料的高温软熔特性实验研究,讨论氧气高炉气氛与传统高炉气氛下炉料软熔特性的差异,初步探索氧气高炉软熔带的形成及分布规律。采用程序还原及软熔实验装置,通过设定升温制度及分段改变煤气成分来模拟烧结矿、球团矿及其混合矿在氧气高炉与传统高炉中的还原及软熔行为,对炉料在氧气高炉工艺条件下的还原及软熔性质演变规律作出分析判断。以氧气高炉数学模型为基础,采用自制的单颗粒还原实验装置对球团矿在H2、CO以及两者的混合气氛中的还原行为及其交互作用进行了研究;采用颗粒模型与三界面未反应核模型相结合的方法对球团矿在CO/CO2/H2/H2O/N2混合气氛下的还原行为进行数值模拟研究;用单颗粒焦炭溶损实验装置,分别对H2O、CO2以及两者的混合气氛中的焦炭的溶损行为及其交互作用进行了研究。通过利用仿真模拟系统建立了氧气高炉的数学模型对氧气高炉的内部运行状况进行了深入研究,分别采用粘性流方法和离散元方法对炉料下降运动进行数值模拟研究;建立了高炉风口回旋区的二维数学模型,对氧气高炉中气体的流动、煤粉颗粒的运动、气体的传热(气体间的传热和气体与颗粒间的传热等)、颗粒的传热(颗粒之间的传热及与气体间的传热等)、燃烧(煤粉和焦炭的燃烧)等过程进行了深入研究;通过建立一维和二维的气固换热与反应动力模型,对氧气高炉内部的温度分布、压力分布以及不同相之间的换热情况进行了深入了解。

At present,traditional blast furnace with coke as main energy has been almost perfect in production efficiency andenergy utilization, and it is difficult to realize the more energy saving and emission reduction by its technical progress inthe traditional blast furnace. Oxygen blast furnace (OBF), as a new iron-making process, has the outstanding advantages incarbon saving and low CO2 emission.Due to the operations of pure oxygen instead of the hot blast and recycling most of thetop gas after CO2 removal, the content of CO and H2 in OBF increases significantly, which may also lead to the metallurgicalperformances of burden change. In order to promote the industrial application of OBF iron-making process, the systematicstudy of OBF ironmaking process was carried out. A comprehensive mathematical model of OBF was established. Manypreliminary designs of OBF were simulated with the comprehensive mathematical model. The comprehensive evaluation of several different OBF process and traditional blast furnace has been made respectively. Through the evaluation, the mostsuitable process of OBF was identified. In order to analyze the low temperature reduction degradation behavior characteristicsunder the OBF atmosphere, low temperature reduction degradation experiments of ores have been carried on in differentatmospheres which are based on the OBF mathematical model. The softening-melting properties of burden at different reducingatmospheres on the softening-melting properties of burden in OBF atmosphere were studied by using the facility of hightemperature reduction-molten experiment. Using the programmed reducing and softening-melting experiment apparatuses, thereduction, softening and melting behaviors of sinter, pellet and mixture of both have been examined by simulating theconditions in traditional BF and typical OBF. It is preliminary founded the formation rule of cohesive zone under the OBFcondition. The reduction behaviors of pellet in the atmospheres of H2, CO and mixture of both were studied by using the selfregulatingreduction experiment apparatus of single particle. The reduction model of pellet, which was applicable to theresearch of the kinetic of non-isothermal reduction of pellet at the atmosphere of one or more gases of CO, CO2, H2, H2Oand N2, was built based on the grain model and unreacted core model with three interfaces. The OBF internal operationconditions are studied by using the mathematical model.