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建立了折流式移动流化床内利用改质焦炉煤气进行气基粉铁矿预还原的数学模型。模型求解采用FLUENT和PHOENICS的联合求解。冷态工况的数值模拟结果和试验结果进行了比较。通过比较床层平均压降和分析气固相的流动行为,对提出的数学模型的可靠性进行了验证。利用所建立的数学模型对利用该反应器和采用改质COG(焦炉煤气)对铁矿粉预还原的工艺过程进行了热态模拟。在模拟的工况条件下,指出了反应器内分布板布置上的缺陷;反应器必须采用气体分布板振动才可以保持气固正常流动,同时保持较小的流化气速。还原气温度的整体降幅达到770K,气相还原势的利用率达到35%,矿粉的还原分数达到0.7,反映出该反应器内良好的气固换热和对还原势的利用率。该反应器在一个紧凑的结构下实现了对还原气热能和还原势的梯级利用。
A mathematical model for pre-reduction of aero-based iron ore by using upgraded coke oven gas in a baffled mobile fluidized bed was established. The model solution uses the joint solution of FLUENT and PHOENICS. The numerical simulation results of cold condition and the test results are compared. The reliability of the proposed mathematical model was verified by comparing the average pressure drop across the bed and analyzing the gas-solid flow behavior. The mathematical model was established to simulate the process of pre-reduction of iron ore by using this reactor and modified COG (coke oven gas). Under simulated working conditions, the defects in the disposition of the distributor plate in the reactor were pointed out. The reactor must be vibrated by the gas distributor plate to keep the normal gas-liquid flow while maintaining a small fluidized gas velocity. The overall reduction of the reducing gas temperature reached 770K, the utilization rate of the vapor-phase reduction potential reached 35% and the reduction fraction of the mineral powder reached 0.7, which reflected the good gas-solid heat exchange and utilization rate of the reduction potential in the reactor. The reactor achieves a cascade utilization of the thermal energy and the reduction potential of the reducing gas under a compact structure.