Process Intensification of Continuous Antisolvent Crystallization Using a Coiled Flow Inverter

The present work experimentally studies the antisolvent continuous crystallization of flufenamic acid using the coiled flow inverter (CFI) as a novel crystallization device. A multistage antisolvent addition strategy was evaluated. The experimental results show that the mean crystal size increased with the number of antisolvent addition points in the CFI. The continuous CFI crystallizer produced crystals of a smaller size with narrower size distributions as compared to the Kenics crystallizer and tube crystallizer without mixing elements at the same process conditions. The effect of the number of flow inversions on the size distribution of the flufenamic acid crystals was studied. The mean crystal size and the coefficient of variation decreased as the number of equally spaced 90 degrees bends increased. Using the population balance equation, it was found that an ideal plug flow model can accurately describe the CFI continuous crystallization process. Overall, this work shows that the CFI crystallizer successfully intensifies the continuous antisolvent crystallization process.