A steady-state precipitation model for flowsheet simulation and its application

Precipitation of sparingly soluble salts is an important process to produce solid products as color pigments or catalysts. High levels of supersaturation are obtained in this process during the mixing step. Consequently, reaction timescales are fast and mixing often influences the product particle size distribution (PSD). In this work, we present a generic model for flowsheet simulation of steady-state precipitation of sparingly soluble salts. Model validation is performed by experiments involving barium sulfate precipitation from aqueous solutions in a confined imping jet mixer (CIJM). Furthermore, experimental and simulative methods are applied to investigate the influence of recycle streams on the product PSD. The experiments show an increase in the average particle size for high recycle flows which is well-predicted by the model. We, furthermore, demonstrate by simulations that recycled particles influence the supersaturation buildup in the CIJM only if a critical particle density is exceeded. (C) 2019 Elsevier Ltd. All rights reserved.