In the present study, numerical simulation, regression modeling, sensitivity analysis, and optimization are implemented to analyze how the reduction rates of wustite pellets are affected by the operational variables. Overall reduction time as a function of temperature, pellet diameter, porosity, gas ratio, tortuosity, gas utility, and pressure was computed by the numerical solution of the time-dependent governing differential equations describing the gas concentrations and temperature variation within a porous pellet of wustite. Bulk temperature, pressure, and pellet size were selected based on the screening analysis, which were then used for the main regression modeling to quantify and evaluate their effects on the overall reduction time. The resulting correlation equation gives the reduction time as a function of the important reaction conditions, within their selected ranges, without having to numerically solve the complex partial differential equations. The pellet diameter and pressure were the two most influential factors, followed by other ones. The sensitivity analysis results showed that the higher the temperature and pressure, the less influential their variations in the reduction time, especially at small pellet diameters. On the other hand, the reduction time displayed the highest sensitivity to the aforementioned variables for large pellets and at low pressures and temperatures.

中文翻译：

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响应面法分析多孔维氏体球团的气体还原

在本研究中，通过数值模拟、回归建模、敏感性分析和优化来分析操作变量如何影响方铁矿球团的还原率。作为温度、颗粒直径、孔隙率、气体比、曲率、气体效用和压力的函数的总还原时间通过描述多孔颗粒内气体浓度和温度变化的时间相关控制微分方程的数值解计算方铁矿。根据筛选分析选择体积温度、压力和颗粒大小，然后将其用于主要回归模型以量化和评估它们对总还原时间的影响。由此产生的相关方程给出了作为重要反应条件的函数的还原时间，在它们选择的范围内，而不必对复杂的偏微分方程进行数值求解。球团直径和压力是影响最大的两个因素，其次是其他因素。敏感性分析结果表明，温度和压力越高，它们对还原时间的影响越小，尤其是在小球团直径时。另一方面，还原时间对大颗粒和低压和低温下的上述变量表现出最高的敏感性。其次是其他的。敏感性分析结果表明，温度和压力越高，它们对还原时间的影响越小，尤其是在小球团直径时。另一方面，还原时间对大颗粒和低压和低温下的上述变量表现出最高的敏感性。其次是其他的。敏感性分析结果表明，温度和压力越高，它们对还原时间的影响越小，尤其是在小球团直径时。另一方面，还原时间对大颗粒和低压和低温下的上述变量表现出最高的敏感性。