CO-N2还原球团矿的本征数学模拟与动力学预测  

Intrinsic mathematical simulation and kinetic prediction of CO-N2 reduction of pellets

作　　者：甘畅 李逵 张伟[1] 张菊花[2] 薛正良[2] GAN Chang;LI Kui;ZHANG Wei;ZHANG Juhua;XUE Zhengliang(Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China)

机构地区：[1]武汉科技大学钢铁冶金与资源利用省部共建教育部重点实验室,湖北武汉430081 [2]武汉科技大学钢铁冶金新工艺湖北省重点实验室,湖北武汉430081

出　　处：《钢铁》2023年第12期12-22,共11页Iron and Steel

基　　金：湖北省重点研发计划资助项目(2022BCA058)。

摘　　要：根据传统宏观动力学分析仅能“模拟”而无法“预测”未知试验,提出本征数学模拟及预测的方法以解决传统动力学分析方法中存在的参数调整随意性强、预测准确性差等系统性问题。采用热重法进行了5组不同温度下(1 235、1 275、1 326、1 377和1 425 K)一氧化碳还原球团矿的等温动力学试验来获取本征动力学参数集合,再对试验数据进行模拟复原,并且对1 254和1 301 K下的反应进行了预测。由还原速率的转折点可将还原过程分为2段,反应前期主要为球团矿中的Fe2O3还原为浮氏体的过程,由一级化学反应控制,反应后期主要为浮氏体还原为铁的过程,由缩核模型控制。反应前后期的转折点的还原度Dtp与温度T之间的关系由方程Dtp=9.101 4×10^(-4)T-0.787 4确定。各反应时期的本征动力学参数分别为,一级化学反应活化能为40.63 kJ/mol,频率因子为52.43 g/(m^(2)·s);外扩散等效活化能为53.58 kJ/mol,频率因子为3.04 m/s;界面化学反应活化能为37.87 kJ/mol,频率因子为0.72 m/s;内扩散等效活化能为85.12 kJ/mol,频率因子为0.09 m^(2)/s。根据最适反应机理建立分段速率微分方程,利用4阶Runge-Kutta法模拟出球团矿还原的初始动力学过程并预测了球团矿在1 254和1 301 K下的动力学曲线,在不同温度下所选时间节点处球团矿动力学曲线的本征数学模拟结果和预测结果与试验结果的相对误差均为6%以内。The unknown experiment could be simulated but is unpredictable according to traditional macro-kinetic analysis.The method of intrinsic mathematical simulation and prediction is proposed to solve the systematic problems such as arbitrary parameter adjustment and poor prediction accuracy in the traditional kinetic analysis.The isothermal kinetic experiments of pellets reducing by carbon monoxide at five different temperatures(1235,1275,1326,1377 and 1425 K)were carried out by thermogravimetric method to obtain a set of intrinsic kinetic parameters.Then the experimental data were simulated and restored,and the reactions at 1254 and 1301 K were predicted.The reduction process was divided into two stages according to the transition point of the reduction rate,in the early stage of the reaction,Fe2O3 in pellets is mainly reduced to wustite,which is controlled by the first-order chemical reaction,and in the later stage,the main process is the reduction of wustite to iron,which is controlled by the shrinking core model.The relationship between the reduction degree Dtp at transition point and the corresponding reaction temperature is determined by the equation Dtp=9.1014×10^(-4)T-0.7874.The intrinsic kinetic parameters of the reactions are as follows.The activation energy of the first-order chemical reaction is 40.63 kJ/mol,and the frequency factor is 52.43 g/(m^(2)·s);the external diffusion effective activation energy is 53.58 kJ/mol and the frequency factor is 3.04 m/s;the activation energy of interfacial chemical reaction is 37.87 kJ/mol,and the frequency factor is 0.72 m/s;the internal diffusion effective activation energy is 85.12 kJ/mol and the frequency factor is 0.09 m^(2)/s.According to the optimal reaction mechanism,the piecewise rate differential equation is established,and the fourth-order Runge-Kutta method was used to simulate the initial kinetic process of pellet reduction and predicted the kinetic curve of pellets at 1254 and 1301 K.At different temperatures,the relative errors between the intrinsic math

关 键 词：本征数学模拟 热重法 球团矿 等温动力学 速率微分方程 

分 类 号：TF046.6[冶金工程—冶金物理化学]