Abstract:

In order to realize continuously and rapidly prepare core-shell structured nanoparticles, a high-frequency impinging stream (HFIS) reactor is explored on the basis of the secondary rotation principle. In this reactor, not only the homogeneous nucleation and heterogeneous nucleation are coupled together, but the liquid-liquid multi-scale mixings are greatly intensified. And then, well-defined nano Fe₃O₄/MnOOH composites were fleetly obtained. The influences of four parameters on the macro and intrinsic kinetics of the coating process were investigated and discussed. Experimental results revealed that low coating ratio prolonged the induction period. Higher initial flux of the main stream intensified the initial dispersion, meso-mixing and micro-mixing. With the total flux of the branch streams being lowered, the initial dispersion was bad off. Furthermore, the computational fluid dynamics (CFD) simulations indicated that the inner layer of the S-shaped main stream had lower pressure and higher flow rate distributions. Therefore, the impinging points should be located in there. Two design defects of the reactor were found, and the corresponding improved schemes were proposed. Through continuous improvement, this reactor is promisingly used for the large-scaled, low-cost and high-quality production of various core-shell nanomaterials.

Key words: reaction engineering, mixing, nanomaterials, high gravity, impinging stream, film-coating

摘要：

一种基于二次旋转的高频撞击流反应器实现了连续快速制备核壳型纳米复合粒子的工艺过程。该反应器将均相成核与异相成核过程耦合在一起, 并显著强化了液液多尺度混合过程。通过制备Fe₃O₄/MnOOH纳米复合粒子, 初步探究了包覆率、主流量、支流总量和撞击点位置对包覆过程宏观与本征动力学过程的影响。发现了反应器存在的一些不足之处及改进方法。反应器经不断改进, 有望实现大规模、低成本、高质量生产各种纳米复合粒子的工艺过程。

关键词: 反应工程, 混合, 纳米材料, 超重力, 撞击流, 膜包覆