【摘要】 均四甲苯与其同分异构体沸点相近、熔点相差较大,不适合采用精馏精制,而宜采用熔融结晶方法进行分离。在考虑固液相界面温度随冷剂温度变化的前提下,采用解析迭代法研究均四甲苯熔融结晶动力学并设计实验进行验证。利用非线性最小二乘法对等温实验数据进行拟合得到不同冷剂温度下的组合动力学参数,并通过多项式拟合得到了组合动力学参数随冷剂温度的变化关系。将其应用于模拟非等温结晶过程的晶体生长,计算结果与实验数据基本吻合,表明该模型能很好地预测晶层生长过程。更多还原

【Abstract】 The boiling points of tetra-methyl benzene are very close,which is difficult to separate by distillation.But the differences of melting points in-between isomers are quite distinctive.Therefore,the static melt crystallization is feasible to separate and purify durene from its isomers.Considering the change of surface temperature between solid and liquid phase with the coolant temperature,the dynamics of static crystallization is studied by analytic iteration method and verified by experiments.The nonlinear least square method is applied to estimate the combined dynamic parameter by fitting the experimental data of isothermal crystallization and the relationship between dynamic parameter and coolant temperature is obtained by fitting of a polynomial.The results were used to simulate the crystal growing during nonisothermal crystallization process and the calculated results fitted well with experimental results,which indicated that the model can predict the growing of the crystalline layer very well.更多还原