Study On Crystallization Process Of Acenaphthene

Acenaphthene is a sort of organic synthesis material and widely applied in plastic,dyestuff, pesticide industry etc. with the development of fine chemicals, the domain of acenaphthene also unceasingly is expanding, thus set a higher request to the product quality. Acenaphthene is refined through cooling crystallization in order to improve product quality.The process technics is simple and advantageous for the industrialization production, simultaneously, may remarkably improve the product quality. Therefore, the cooling crystallization of acenaphthene was studied systematically both in experiment and theory, including crystallization thermodynamics, crystallization kinetics,crystallization process and crystallization process simulation.Crystallization threomdymics is the key factor indiciding the production yield and the selection of crystallization process. In this thesis, the solubility of acenaphthene in different solvents(A, B, n-butyl alcohol, Methyl benzene) were measured using a laser technique. The experimental data were correlated with Apelblat equation.It is shown that this equation can correlate the solubility data as well.At the same time, the supersolubility of acenaphthene in different solvents(A, B, n-butyl alcohol) were also determined using the laser technique. Thus, we can obtain metastable zone for cooling crystallization. The datas provide the theory basis for the crystallization process and has the instruction significance with operating control, process design, optimization and scale-up.The nucleation and growth rate in crystallization kinetics have an important influence on crystal-size distribution(CSD) and is the basis for understanding of the crystallization behavior and crystallizer scale-up dsign. The kinetics of acenaphthene was studied by the moment transformation method. By using the least square method for the multivariate linear regression, the kinetic parameters under the considered experimental conditions were obtained. The experimental kinetic data is useful for process simulation and scale-up. Based on the data and experiments, the optimum process was obtained.According to product yield, crystal-size distribution CSD and SEM, cooling crystallization of acenaphthene is optimized experimentally on the basis of crystallization thermodynamics and crystallization kinetics study. The effect of operating parameters such as seeds added, agitation speed, cooling rate, on the crystallization process and product quality was studied. The experiential optimum operating conditions for cooling crystallization process of acenaphthene in different content were finally obtained.The mathematical model on moment transformation method was simplified into system of ordinary differential equations with nucleation rate equation, growth rate equation, solubility equation, cooling rate equation etc.It was solved by Runge-Kutta method. The effect on crystallization of acenaphthene in different operating conditions was simulated according to the method above. The simulated results has the instruction significance with scale-up and industrial production operation.