Characterising flow with continuous aeration in an oscillatory baffle flow reactor using residence time distribution

Abstract

Multi-phase flow occurs in many reactions with gas, an integral part of the reaction. This study assesses the synergistic impact of continuous aeration and velocity ratio on mixing conditions within an oscillatory baffled flow reactor to enhance the degree of plug flow, quantified by a tanks-in-series (TiS) model. A bubbly flow regime is shown in all experiments. In most cases, the TiS value was reduced with gas flow, and a maximum TiS value of 23.6 was achieved at a velocity ratio of 3.8 at 225 ml min⁻¹ in a counter-current direction. Single-phase runs and co-current multi-phase runs produced maximum TiS values of 23.5 and 18.2 respectively at a velocity ratio of 2.2. Regardless of the gas flow rate, the velocity ratio was found to be the most influential factor that dictates the level of plug flow within the OBR. A predictive model is developed and used to maximise the mixing efficiency by determining the level of plug flow within the OBR at selected amplitudes, frequencies, and gas flow rates.