Kinetics modeling and optimized operation in batch seeded crystallization of potassium aluminum sulfate

• Main Authors: Bo-Wen Chen, 陳柏彣
• Other Authors: Jeffrey D.Ward
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/61084409005821545843

碩士 === 國立臺灣大學 === 化學工程學研究所 === 104 === In this work batch crystallization experiments of potassium aluminum sulfate was performed with manipulating various operation valuables. Experimental results are used to determine the kinetic parameters of nucleation rate and growth rate. The second part of this work is computer program simulation to optimize temperature trajectories operating batch cooling experiment with specific objective function. The purpose of the desupersaturation experiment is to determine the kinetic parameters of growth rate equation. Data are collected under different conditions, degree of supersaturation and temperature and fit to the model form G=(T,S)=〖 k〗_g e^((-E_a)/RT)×S^g. There are two experimental variables in this simulation: temperature (T), supersaturation (S). We can determine the pre-experimental factor (〖 k〗_g), activation factor (E_a) and g opponent for potassium aluminum sulfate by regression. In batch cooling crystallization, the results show that we achieve different crystal size distribution by manipulating the cooling rate and the initial degree of supersaturation. The study also include the crystal size distribution(CSD) and volume size distribution(VSD) result of the crystal products measured by Laser Diffraction Particle Size Analyzer(Coulter LS230). In this study we investigate the growth rate, and nucleation based on the CSD results. Furthermore, we analyze the CSD and VSD with the growth rate dispersion model. The dispersion model show that the effect of growth rate dispersion on the crystal size distribution may be significant. In this study, the result show the CSD and VSD comparison between constant growth rate model and Gamma distribution type of growth rate dispersion model. The method of optimizations are the method of iteration. This work use Matlab program to construct the optimization problem which is to find the minimum μ_(3.n)/μ_3 (minimize the nucleation mass) which is the objective function in this work.