An Experimental Investigation into the Scale-up of Oscillatory Flow Mixing in Baffled Tubes

Abstract

his paper describes results from an experimental investigation into the scale-up of oscillatory flow mixing (OFM) in geometrically scaled baffled tubes ranging from 24 mm to 150 mm diameter and from 1 m to 4.5 m in length. Measured axial dispersion coefficients are reported together with case studies and an empirical correlation. An alternative multi-orifice reactor geometry with the potential for use in large-scale plant was also constructed and tested from which it was concluded that OFM is a technology which lends itself readily to scaling-up from laboratory to pilot plant scale, and to industrial scale. Experiments performed on small laboratory OFM apparatus containing less than one litre of fluid can with confidence be used to predict mixing behaviour in much larger plant containing hundreds of litres of fluid.

Biological processing in oscillatory baffled reactors: operation, advantages and potential

“…Generates increased particle flotation [33,34] increased mass transfer uniform bubble size and increased gas hold up produce enhanced mass transfer rates sixfold and 75% increases for oxygen transfer (k L a) into water and yeast culture, respectively [28,35] compact reactor design the ability to generate long residence times, under plug flow, with reduced reactor lengths allows compact designs up to a 600-fold decrease in reactor length compared with conventional tubular reactors [36] linear scale-up maintaining St, Re o and Re n allows mixing intensity and flow conditions to be predicted in large volume OBRs using data from laboratory-scale experiments laboratory-scale experiments can be scaled up by increasing OBR diameter or length while maintaining predictability [29,37,38] rsfs.royalsocietypublishing.org Interface Focus 3: 20120036…”

“…St, Re o and Re n are assumed to fully define the fluid dynamic conditions for a particular OBR geometry [37]. By keeping these parameters constant, an OBR with a diameter of, for example, 24 mm should behave the same as one with a diameter of 150 mm.…”

“…By keeping these parameters constant, an OBR with a diameter of, for example, 24 mm should behave the same as one with a diameter of 150 mm. Axial dispersion coefficients (D c ) have been used to study the effects of tube diameter on the mixing and flow conditions of three OBRs with 24, 54 and 150 mm diameters [37]. An imperfect pulse technique was adopted and the pulse concentration measured at a minimum of two points downstream.…”

“…Three distinct flow regimes were indentified: for [37]. Optimal interaction between the net flow and oscillatory mixing was identified as the reason for the minimum: at 80 , Re o , 800, the vortices created were optimal for radial redistribution of dye, thereby minimizing axial dispersion [29].…”

CO2 Dissolution and Design Aspects of a Multiorifice Oscillatory Baffled Column

“…An additional feature perhaps unique to OBCs is its linear scale-up in some particular applications, 15,[21][22][23] however no rules have yet been established in respect to scale-up of gas-liquid mixing in OBCs.…”