Quantification and evaluation of operating parameters’ effect on suspension behavior for slug flow crystallization

Abstract

As small scale continuous crystallizers gain more attention, the challenge of suspension inside tubular crystallizers was recognized, which might be circumvented by using slug flow crystallization. In literature, the effects of operating conditions, like slug’s velocity, slug’s length, solid content, and crystal size are investigated qualitatively only. A quantitative method describing the suspension state under gravitational influence for tubular crystallizers is not established yet and developed in this study. Therefore, the goodness of suspension (GoS) is introduced describing the particles’ spread inside the slugs in horizontal and vertical direction. The GoS is systematically analyzed for different operating conditions using design of experiments. Results show that independent of the other operating conditions smaller slugs are favored for better GoS in horizontal direction only. The choice of slug’s velocity depends for vertical and horizontal direction on solid content and crystal size, whereby both of them are defined by crystalline product requirements.