Considering the characteristics of large cylindrical shell rolling, such as double driving rolls, asymmetrical rolling and huge workpiece, a slab method was developed to establish the rolling force model. In this mode...Considering the characteristics of large cylindrical shell rolling, such as double driving rolls, asymmetrical rolling and huge workpiece, a slab method was developed to establish the rolling force model. In this model, the non- uniform normal and shear stresses and the upper and lower surface temperatures of the workpiece were taken into ac- count. Moreover, the flow stress model, considering the dynamic recovery and dynamic recrystallization behaviors of the material, was established. The rolling pressure distribution, the rolling force, the rolling torque and the neutral points could be calculated quickly and easily by the roiling force model. The predicted results were shown to be in good agreement with the measured values, which indicated that the model can satisfy the requirement of industrial application.展开更多
采用双驱动反应器研究了热钾碱吸收二氧化碳的反应动力学,根据双膜理论,应用CO_2-H_2O体系,实验首先对气相传质过程进行了研究,结果表明:当气相体积流量为80 m L·min^(-1)时,气相搅拌速度在100 r·min^(-1)时可认为气膜阻力消...采用双驱动反应器研究了热钾碱吸收二氧化碳的反应动力学,根据双膜理论,应用CO_2-H_2O体系,实验首先对气相传质过程进行了研究,结果表明:当气相体积流量为80 m L·min^(-1)时,气相搅拌速度在100 r·min^(-1)时可认为气膜阻力消去.通过改变液相搅拌转速,研究了液相传质系数kL变化规律,获得了k_L的无因次关联式.根据热钾碱吸收CO_2反应机理,获得了宏观动力学方程,并结合溶液的非理想性,对速率方程中的浓度效应进行了校正,通过实验测定并进行了模型参数估值,各参数分别为:表观活化能E_(ob)=21.9308 k J·mol^(-1),表观反应级数n=0.1399,表观指前因子K'_0=1.1908×10^(-4)mol·m^(-2)·s^(-1)·Pa^(-1).在此基础上,通过计算获得了热钾碱吸收CO_2的本征动力学方程,各模型参数分别为:本征反应活化能E=59.57 k J·mol^(-1),指前因子k_0=2.1802×1011m^3·mol^(-1)·s^(-1).为进行整个过程反应机制的判断,计算了膜内转化系数γ,结果表明该值远大于2,可知CO_2吸收为快速反应过程,反应主要集中在膜内完成,并由此可知工业反应器选型应采用比相界面积较大的填料塔为优.展开更多
基金Item Sponsored by National Science and Technology Major Project of China(2011ZX04002-101)National Science and Technology Support Plan of China(2011BAF15B02)National Natural Science Foundation of China(51305388)
文摘Considering the characteristics of large cylindrical shell rolling, such as double driving rolls, asymmetrical rolling and huge workpiece, a slab method was developed to establish the rolling force model. In this model, the non- uniform normal and shear stresses and the upper and lower surface temperatures of the workpiece were taken into ac- count. Moreover, the flow stress model, considering the dynamic recovery and dynamic recrystallization behaviors of the material, was established. The rolling pressure distribution, the rolling force, the rolling torque and the neutral points could be calculated quickly and easily by the roiling force model. The predicted results were shown to be in good agreement with the measured values, which indicated that the model can satisfy the requirement of industrial application.
文摘采用双驱动反应器研究了热钾碱吸收二氧化碳的反应动力学,根据双膜理论,应用CO_2-H_2O体系,实验首先对气相传质过程进行了研究,结果表明:当气相体积流量为80 m L·min^(-1)时,气相搅拌速度在100 r·min^(-1)时可认为气膜阻力消去.通过改变液相搅拌转速,研究了液相传质系数kL变化规律,获得了k_L的无因次关联式.根据热钾碱吸收CO_2反应机理,获得了宏观动力学方程,并结合溶液的非理想性,对速率方程中的浓度效应进行了校正,通过实验测定并进行了模型参数估值,各参数分别为:表观活化能E_(ob)=21.9308 k J·mol^(-1),表观反应级数n=0.1399,表观指前因子K'_0=1.1908×10^(-4)mol·m^(-2)·s^(-1)·Pa^(-1).在此基础上,通过计算获得了热钾碱吸收CO_2的本征动力学方程,各模型参数分别为:本征反应活化能E=59.57 k J·mol^(-1),指前因子k_0=2.1802×1011m^3·mol^(-1)·s^(-1).为进行整个过程反应机制的判断,计算了膜内转化系数γ,结果表明该值远大于2,可知CO_2吸收为快速反应过程,反应主要集中在膜内完成,并由此可知工业反应器选型应采用比相界面积较大的填料塔为优.
