On the measurement of strain rate in an oscillatory baffled column using particle image velocimetry

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…”

“…A comparison is shown in figure 3 using the lowest estimation of shear for a 2 l STR [41], previously used for comparison against a 50 mm OBR (251 Re o 4021) [33]. The average shear rate has been plotted against power density (P/V): a measure of energy being applied to a system, expressed in W m 23 .…”

“…A 60 per cent improvement in flotation for finer particles, less than 30 mm, and 30 -40% for coarse particles up to 104 mm at much lower power densities compared with conventional flotation devices were reported. Compared with Rushton impeller agitated flotation devices that can have up to 30-40 times the energy dissipation close to the impeller compared with the bulk of the vessel [49], OBRs have been shown to have a more even distribution of shear [33], explaining the improvements in flotation. This strongly suggests that OBRs are suitable for performing bioprocesses containing biomass particles that need to be retained in suspension without sedimentation.…”

“…Previous authors have commented on the non-homogeneous nature of STRs that results in floc break-up near the impeller zone where shear rates can be two orders of magnitude higher than the average [91]. The more even shear distribution in OBRs [33] allows flocculation to occur at much lower average shear providing an attractive, alternative flocculation device to STRs [75].…”

Liquid culture of microalgae in a photobioreactor (PBR) based on oscillatory baffled reactor (OBR) technology – A feasibility study

“…Vortices form down the length of the OBR as material is forced through periodically spaced orifice plates (baffles). The advantages of this agitation type include uniform mixing at low shear (Ni et al, 2000), enhanced mass (Hewgill et al, 1993, Ni et al, 1995 and heat (Mackley and Stonestreet, 1995) transfer, the possibility of linear scale-up (Smith andMackley, 2006, Smith, 1999) and power efficient agitation (Abbott et al, 2014b, Jambi et al, 2013. The mixing intensity is also decoupled from the net flow rate which enables plug flow to be achieved in substantially shorter reactors compared to conventional tubular designs where high net flows are required for turbulence (Stonestreet and van der Veeken, 1999, van Vliet et al, 2005, Stonestreet and Harvey, 2002, Abbott et al, 2014a.…”