Scale-Up of a Semi-Batch Draft Tube Baffled Crystallizer for Hexanitrohexaazaisowurtzitane Based on Experiments and Computational Fluid Dynamics Simulation

In this study, experimental work was carried out for the production of microsized hexanitrohexaazaisowurtzitane (HNIW) in a 500 L draft tube baffled (DTB) crystallizer. Acetone and isopropanol were used as the solvent and antisolvent. From the experimental data, the kinetic parameters of the nucleation and growth rates were obtained by the maximum likelihood method. The kinetics was then used in the computational fluid dynamics simulation of a 500 L crystallizer. The simulation results were compared to the experimental data in terms of crystal size distribution, which showed a marginal error. On the basis of this mathematical model, the 500 L DTB crystallizer was scaled-up to 3000 L. Case studies were conducted on the 3000 L DTB crystallizer with one and two draft tubes. HNIW solid volume fraction, particle mean diameter, and particle size distributions were compared for both cases, which led to the conclusion that the two draft tube crystallizer showed better performances. Finally, the result of this paper envisaged dealing with the scale-up of the DTB crystallizer based on the experimental results and computational fluid dynamics simulations.