Liquid flow field and residence time distribution in a baffleless oscillatory flow coil reactor

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-07, Vol.492, p.151758, Article 151758
• Main Authors: Fadaee, Mohammad Mahdi, Doyle, Brendon J., Roberge, Dominique M., Macchi, Arturo, Haelssig, Jan B.
• Format: Article
• Language: English
• Subjects: 3D flow field; Baffleless coil; Flow oscillation; RTD; Skewed normal distribution model
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.151758

•Liquid RTD measured in a baffleless oscillatory flow coil reactor.•3D instantaneous flow field simulated by CFD.•RTD fitted to a skewed normal distribution model.•RTD model fitted to generalized operating conditions and coil geometry.•Oscillation amplitude used as characteristic length in the Dean number. Baffleless coils can operate as continuous oscillatory flow reactors to produce pharmaceutical products where process intensification is intended. A method to evaluate mixing performance and its impact on reaction conversion is residence time distribution (RTD) analysis. Liquid macromixing in a long baffleless coil reactor (L = 24 m, dt = 4.57 mm) at ranges of oscillation amplitude (11.75–58.75 mm), frequency (0–3.68 Hz), and net flow rate (30–120 g⋅min−1) was investigated based on measured RTDs fitted to the skewed normal distribution model. The impact of operating conditions on the RTD was supported by analyzing the liquid flow field derived from CFD simulations. The RTD variance under different oscillation conditions suggests a near plug flow pattern, although deviations from ideality such as skewness and long tailing were always observed. The model parameters, along with the RTD variance, were correlated to the operating conditions lumped in an oscillatory Dean number that used the flow amplitude as characteristic length (Deox). Values of Deox varied between 150 and 11000, and the RTD variance at the different net flow rates was minimized for 300