Liquid flow residence time in a fibrous fixed bed reactor with recycle

Modeling hydrodynamic behavior in fixed bed bioreactors under different hydraulic conditions via Retention Time Distribution

“…Besides, number of stirred tanks significantly increased from 1.5 to 4 and dispersion coefficient also increased from 0.11 to 2.14 cm 2 .sec -1 along with the increase of HLR in GF, which means that a higher HLR contributes to more volume for plug flow and greater water dispersion. Similarly, Martinov et al [8] verified a power relationship between the number of mixed cells and liquid velocity in a fibrous fixed bed reactor, who found that the low flow velocity ensuring a high reactor mean residence time contributed to low N values between 1 and 2. However, the change of number of stirred tanks in PF was not evident with the same value of 1.5, although the dispersion coefficient increased from 0.21 to 1.61 cm 2 .sec -1 , which means that the media with a large porosity helps the filter bed to resist to a great change of hydraulic loading rate.…”

Advanced Oxidation of Tartrazine and Brilliant Blue with Pulsed Ultraviolet Light Emitting Diodes

“…This oscillation is more pronounced for some conditions than for others. Oscillations in chemical reaction are often attributed to the role of stable and unstable steady states, and have been widely reported for water treatment unit operations (Marek and Svobodova, 1975;Benjamin and Lawler, 2013;Bodin et al, 2012;IAEA, 2011;Martinov et al, 2010;Qi et al, 2012;Wols et al, 2010). These oscillations arise from non-ideal mixing conditions, reactor hydraulics leading to multiple flow paths, and variations in radiation intensity (Wols et al, 2010).…”

Hydrodynamic Mathematical Modelling of Aerobic Plug Flow and Nonideal Flow Reactors: A Critical and Historical Review

“…These tests approached the plug flow for porous bed reactors, low bed porosity, low liquid and/or gas velocity. However, different authors demonstrated that back-mixing could occur in such reactors depending on the bed length, size of the packing particles and liquid phase velocity (Froment and Bischoff, 1990;Martinov et al, 2010 fraction of the fixed bed and it is independent of the boundary conditions. Furthermore to account for a deviation from ideal flow, they proposed a schematic model with recirculation.…”

“…Meunier and Williamson (1981), Baquerizo et al (2005), and Jacob et al (1996) proposed a plug flow model neglecting the back-mixing effect. Other models proposed by Fdz-Polanco et al (1994), Martinov et al (2010), Pérez et al (2005), andSanchez et al (2005) included also the back-mixing conditions with the tank in series configurations. Also Séguret and Racault (1998), Froment and Bischoff (1990), Muslu (1984Muslu ( , 1990, and Muslu and San (1990) equations obtaining a more detailed model.…”