Characterization method for mass mixing in batch reactors based on temperature profiles

• Published in: Chemical engineering research & design Vol. 156; pp. 300 - 310
• Main Authors: Camps, Lennart, Moens, Luc, Groth, Urs, Braeken, Leen, Kuhn, Simon, Thomassen, Leen C.J.
• Format: Journal Article
• Language: English
• Published: Rugby Elsevier B.V 01-04-2020; Elsevier Science Ltd
• Subjects: Batch reactor; Chemical reactors; Experiments; Heat and mass mixing; Heat pulse method; Liquid injection; Measurement; Micromixing time; Mixing scales; Reactors; Studies; Temperature effects; Temperature profiles; Turbines; Micromixing time; Heat pulse method; Heat and mass mixing; Batch reactor; Mixing scales
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2020.02.004

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•A novel method is developed to measure heat mixing by injecting a short heat pulse.•Heat mixing is related to mass mixing by a model for a 1 L reactor.•Both convection and conduction are crucial in heat mixing.•The model can predict mixing in the reactor for any solvent or reaction.
Measuring mass mixing in batch reactors is of great interest to prevent yield losses during scale-up of reactions. In this work, we present a novel tool to accomplish this: the heat pulse method. This is a thermal-based technique consisting of a local heat pulse, applied electrically or by a hot liquid injection, during 10 s at a power of 5–15 W and subsequent measurement of temperature increase at locations of interest. The 95% mixing time from corrected and smoothed temperature profile characterizes heat mixing. A heat mixing model identifies the contributions of thermal conduction and convection and hereby relates local heat and mass mixing in a 800 mL in a 1 L batch reactor with a 45° 4 blade downward pitched turbine. The heat pulse method is applicable on different reactors, solvent independent and non-destructive. Experiments are repeatable and mixing at reactive circumstances can be mimicked.