Modeling and optimization of freeze concentration of Wood Vinegar in a swirling fluidized crystallizer

A novel swirling fluidized crystallizer is introduced to address challenges of Wood Vinegar (WV) freeze concentration by utilizing a swirling flow field and fluidization technology. A theoretical force model was established to demonstrate the continuously changing coupled centrifugal forces acting on the micro-interface of ice crystal particles in the swirling fluidized crystallizer. Box-Behnken experiment design and backpropagation neural network (BPNN) are employed to model and optimize the complex crystallization kinetics involved in freeze concentration, providing a better understanding of solute partitioning behavior and more accurate prediction of the performance of WV freeze concentration. Experimental results demonstrate that under optimized freeze concentration conditions (freezing temperature -25.3C, flow velocity 1.00m/s, freezing time 76.6min, seed ice amount 14.6g), the concentration of organic acids in WV is significantly increased, with an effective partition coefficient (K) reduced to 0.1886, indicating effective concentration of organic compounds in the swirling fluidized crytallizer. GC-MS analysis reveals that the concentrated WV retains the chemical profile of the original sample, with significantly enhanced concentrations of key organic components. Comparative analysis shows that the swirling fluidized crystallizer demonstrated better performance in the WV freeze concentration than traditional stirred crystallizer.