Mixing and solid‐liquid mass transfer characteristics in a three phase pulsed plate column with packed bed of solids in interplate spaces—a novel aerobic immobilized cell bioreactor

Abstract

BACKGROUND: The pulsed plate column (PPC) with packed bed of solids in the interplate spaces finds use as a three phase aerobic bioreactor and is a potential heterogeneous catalytic reactor. Good knowledge of the extent of mixing in the liquid phase and solid-liquid mass transfer coefficient are essential for modeling, design and optimization of these columns. The present work aims at the study of liquid phase mixing and solid-liquid mass transfer characteristics in a three phase PPC.

Experimental investigation, modelling, and order of magnitude analysis of oxygen mass transfer in pulsed plate column with α‐Fe2O3 nanofluid

“…The sulphite concentration in the initial stock sulphite solution was determined iodometrically. [10,61] Compressed air was continuously supplied from the bottom of the column at a desired flow rate for aeration at a constant rate. The plates were pulsated at a required frequency and amplitude.…”

“…The sample was centrifuged for 10 min at 10,000 rpm to separate the nanoparticles. The supernatant was analyzed for sodium sulphite concentration by iodometric titration against sodium thiosulphate [10,61] and further, the k L a was determined [55] using Equation ( 1), taking into consideration that the reaction of oxygen and sulphite is instantaneous, as it is catalyzed by cobalt ions.…”

“…The mean bubble diameter is affected by the pulsing velocity, as the additional rigorous shear forces that are created by the increased pulsing velocity cause the collapse of the bigger bubble into smaller ones, hence increasing the interfacial area which increases k L a. [1,10,15,18,85,101] From Figure 9, it is observed that the k L a is increasing with increasing pulsing velocity at different nanoparticle loadings, and the effect of (A Â f) on k L a is found to be segregated over two different regimes in the entire range of (A Â f). Two regimes are observed in the entire range of (A Â f), irrespective of the nanoparticles loading.…”

“…[7] The gas-liquid mass transfer operations in chemical and biological processes are performed in different reactors such as stirred tank reactors, bubble column, rotating disk reactors, oscillatory flow reactor, reciprocating plate columns, pulsed plate columns (PPC), and liquid pulsating column. [1,3,[8][9][10][11][12][13] Reciprocating plate column or PPC, which is an advancement of the bubble column, was developed by Karr [14] and has been found to provide a high interfacial area for gas-liquid mass transfer. Unlike bubble columns, in the PPC, the mixing between the phases is not only facilitated by gas flow through the column but more predominantly by the reciprocating motion of the axially mounted stack of perforated plates.…”

“…Hence, it helps to enhance the gas-liquid mass transfer efficiency. [7,10,[16][17][18] PPCs have been used as biological reactors for aerobic wastewater treatment. [19,20] Several investigations have shown that the enhancement of gas-liquid mass transfer can also be achieved in the presence of a third phase, for example, by dispersing droplets or solid nanoparticles in the reactor fluid.…”