微观混和问题的研究——(Ⅹ)混和对于快速平行反应过程的影响

STUDIES ON MICROMIXING(Ⅹ)INFLUENCES OF MIXING ON PARALLEL REACTIONS

根据作者以往提出的微观混和理论,进一步考虑微观与宏观混和因素对平行反应过程的影响。实验以盐酸与氯乙酸乙酯同氢氧化钠的竞争反应为工作体系,在2.5L 和50L 半分批釜中系统地考察了产物分布 X_Q 随搅拌转速、反应物浓度、进料位置、加料速率、加料方式、体积比等因素的变化规律,实验结果整理为 X_Q 与特征无量纲数 Da、Li 的关系,模型能够较好地预测和模拟这一关系。同时,对大釜和小釜的实验与模拟均表明,反应区域的位置和大小的改变是快速反应产生“放大效应”的重要原因。

The effects of mixing on parallel reactions were considered in this serial paper(X).Two feed- ing modes of reagents in a semibatch reactor were simulated by making use of our micromixing mod- el.Acid-base neutralization and alkaline hydrolysis of ethyl chloroacetate were utilized as the work- ing reactions.Experiments were carried out in two agitated tanks of 2.5 liter and 50 liter repective- ly.The product distribution for various stirrer speeds,feed locations,feed times,initial reagent concentrations and volume ratios were obtained.The results were well treated in the form of X_Q= f(α,Da,Li).Comparison of the model predictions with the experimental data shows that the model is capable of predicting and simulating the effects of micro- and macromixing on parallel reactions. Differences between the results obtained in large and small tanks can be attributed to the“localizing effect”of the reaction zones during mixing.