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

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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