(382d) Turbulent Reactive Transport Effects in Crystallization Processes

Reactive crystallization is fundamental to many industrial processes. Crystallization kinetics, crystal size, and morphology are influenced by the transport of chemical species, thus, decoupling the effects of transport phenomena from chemical reactions is critical to a comprehensive understanding of a given system, especially under turbulent flow conditions.

In this work, we present experimental and numerical studies of the bulk and surface precipitation kinetics of barium sulfate. Experimental studies were carried out in a modular Taylor-Couette (TC) reactor; the reactor configuration and rotational speed were varied to obtain a wide range of wall shear stresses, turbulent flow conditions (Re ≤ 4.3 ×10⁴), and residence times. Reaction rates were obtained through effluent and gravimetric analyses. We apply computational fluid dynamics (CFD) methods to simulate the diffusive and convective transport in the liquid phase. The numerical method was validated against a previously published torque correlation and was found to accurately describe the transport of chemical species. Local turbulent Peclet numbers [1] are used to characterize the increased diffusivity from turbulent advection.

Experimental results show that both bulk precipitation and surface deposition kinetics are strongly influenced by the transport properties of the reacting fluid. The numerical model predicts the locations of high and low crystal deposition, which are in good agreement with experimental observations. The insights from this study provide new understandings of liquid-phase reactions in wall-bounded systems.

Reference

[1] B.U. Anabaraonye, J.R. Bentzon, I. Khaliqdad, K.L. Feilberg, S.I. Andersen, J.H. Walther, The influence of turbulent transport in reactive processes: A combined numerical and experimental investigation in a Taylor-Couette reactor, Chem. Eng. J. 421 (2021) 129591. https://doi.org/10.1016/j.cej.2021.129591.