Gas‐Liquid Hydrodynamics and Mass Transfer in Aqueous Alcohol Solutions in a Split‐Cylinder Airlift Reactor

Abstract

The influences of aliphatic alcohols (C n H 2n+1 OH, n = 1-4) and their concentrations (0-1 vol.-%) on gas holdup, liquid circulation velocity, mixing time, and overall volumetric gas-liquid oxygen mass transfer coefficient were considered in a split-cylinder airlift reactor sparged with air. The carbon chain length of the alcohols and their concentration affect the airlift reactor performance. Alcohols reduced the average bubble sizes and increased the gas holdup, the interfacial area for mass transfer, and the gas-liquid mass transfer coefficient. Since butanol has the most carbon atoms in its chain, it had the most significant effect on gas holdup and mass transfer enhancement. It also decreased the liquid circulation velocity by surface tension reduction. Two correlations based on dimensionless groups were applied to investigate the effect of hydrodynamics and molecules on gas holdup and mass transfer. A satisfactory agreement between correlation and experimental results was observed.

The Influence of Oil-water Ratio on the Operation of an Airlift Reactor Containing Petroleum-based Micro-emulsion

“…The split-cylinder airlift reactor used in this research was the same as the applied apparatus by Moraveji et al (2011). All the experiments were carried out in ambient conditions (atmospheric pressure and 25 ± 0.5 • C).…”

“…All the experiments were carried out in ambient conditions (atmospheric pressure and 25 ± 0.5 • C). Gas holdup, liquid circulating velocity, and oxygen mass transfer coefficient measurement methods have been reported in the literature (Moraveji et al, 2011). Zuber and Findlay's method (1965)I was used to find the flow regimes as well.…”

Hydrodynamics and oxygen mass transfer characteristics of petroleum based micro-emulsions in a packed bed split-cylinder airlift reactor

“…The split-cylinder airlift reactor used in this research was the same as the apparatus applied by Moraveji et al (2011b), as shown in Figure 1 The maximum possible porosity of the packing is equal to 78.0%. As is known, packing normally increases the mass transfer and gas hold-up.…”

“…In this study, the volume expansion method was applied to measure the overall gas hold-up (ε) during the steady state condition in the airlift bioreactor. Liquid circulation velocity (U L ) and oxygen mass transfer coefficient measurement methods have been proposed and reviewed elsewhere (Moraveji et al, 2011b).…”

Hydrodynamics and mass transfer study of oil-water micro-emulsion in a three phase external loop airlift reactor

“…1 This wide application of airli reactors is due to their advantages including low operation and maintenance cost and high mass transfer rate. 3 Oil-in-water micro-emulsions are one of the main wastes of oil renery, chemical and petrochemical companies. Air is sparged through the riser which makes the uid ow upward in the riser and downward in the down-comer.…”