EVALUATION OF SCALE-UP CHARACTERISTICS AND DEVELOPMENT OF SIMULATOR FOR MANUFACTURE OF FUNCTIONAL FINE PARTICLES BY GAS - PHASE METHOD

在本研究的实验部分，1.研制了一套用于制备超细颗粒的带有壁温控制器的反应器，并测量了反应器内壁和内壁的温度分布。通过对反应器内气体速度和温度分布的数值模拟分析，可以从理论上评价反应器内控制颗粒形成的这些分布。还研制了醇钛蒸气或四氯化钛蒸气的产生装置，利用该装置将其中一种蒸气与载气一起送入反应器，进行了制备二氧化钛微粒的实验。用气溶胶测量技术和电子显微镜测定了团聚状态、团聚体和一次粒子的尺寸分布。制得颗粒的性质随反应温度、载气流量和两个…的复杂变化在理论部分，建立了颗粒制备过程的动力学方程，该方程考虑了反应产物的过饱和气氛的形成、凝聚颗粒从单体通过团簇向颗粒的生长、团聚颗粒的形态变化以及初级颗粒的生长和颗粒在非等温流场中的输运。本文构建了一种新的模型，称为二维离散截面模型，通过使用颗粒的比表面积和体积来描述团聚颗粒的尺寸和形貌的同时变化，从而更准确地预测颗粒形成的早期阶段。根据实验结果对所用蒸汽的化学反应速率进行了评估，以将反应速率纳入模型。基于该模型的颗粒制备过程的数值模拟，较好地预测了不同条件下颗粒的大小和形貌。结果表明，本研究提出的模拟技术可以为颗粒制造反应器的设计和放大提供有益的指导。较少

In the experimental portion of this study,1. A reactor equipped with wall temperature controllers for preparation of fine particles was manufactured, and the temperature distribution at the wall and inside of the reactor were measured. Analysis of the gas velocity and temperature distributions in the reactor by numerical simulation showed that these distributions governing particle formation in the reactor could be evaluated theoretically.2. A device for generating titanium alkoxide vapor or titanium tetrachloride vapor was also manufactured, to perform experiments of manufacturing titania fine particles by feeding either of the vapors into the reactor with carrier gas using the device. The state of agglomeration, and the size distributions of agglomerates and primary particles were determined by aerosol measurement techniques and electron microscopy. The complicated changes of the characteristics of manufactured particles with reaction temperature, flow rate of the carrier gas and two … More different vapors were clarified experimentally.In the theoretical portion, a dynamic equation to model the particle manufacturing processes was derived in which formation of supersaturated atmosphere of reaction products, coagulational particle growth from monomers via clusters to particles, morphology change of agglomerated particles by sintering and growth of primary particles and transport of particles in a nonisothermal flow field, were taken into account. Here, a new model called the 2-dimensional discrete-sectional model was constructed to predict the early stage of particle formation processes more accurately by describing the simultaneous change in size and morphology of agglomerated particles using the surface area and volume of the particles. The chemical reaction rates of the vapors used were evaluated from the experimental results to incorporate the reaction rates in the model. Numerical simulation for the particle manufacturing processes based on the model gave good prediction for size and morphology of particles manufactured under various conditions. Consequently, it was made clear that the simulation technique proposed in the present study could give useful guidelines to design and scale-up of particle manufacturing reactors. Less