Scaling of Mixing in Stirred Tank Crystallization Reactors

Abstract

A solver was developed in OpenFOAM to simulate fluid dynamics and competitive-parallel reactions in stirred tank crystallization reactors. The model uses the direct quadrature method of moments (DQMOM) coupled with the interaction-by-exchange-with-the-mean (IEM) model to estimate global mixing sensitive reaction yields. Model development and validation was completed for one small-scale confined impinging jet reactor (CIJR) and two larger-scale stirred tank reactors that utilized the third Bourne, fourth Bourne, and Villermaux-Dushman reactions. Experimental Villermaux-Dushman reaction yield measurements were collected in a small-scale EasyMax 402 crystallization reactor and compared with the implemented DQMOM-IEM model predictions. Experimental measurements were performed using a 50 mm retreat curve, near-impeller dosing with sulfuric acid concentration of 100–400 mol/m3, and impeller speeds of 200–600 rpm. Although the DQMOM-IEM solver predictions are in good agreement with experimental trends, it is necessary to adjust the mechanical-to-scalar (Cϕ) empirical mixing coefficient to obtain good fits for some cases.