The role of gas phase momentum in determining gas holdup and hydrodynamic flow regimes in bubble column operations

1994 ◽  
Vol 72 (1) ◽  
pp. 3-12 ◽  
Author(s):  
I. G. Reilly ◽  
D. S. Scott ◽  
T. J.W Debruijn ◽  
D. Macintyre
Keyword(s):  
Gas Phase ◽  
Bubble Column ◽  
Flow Regimes ◽  
Gas Holdup ◽  
Hydrodynamic Flow ◽  
Phase Momentum

Unified study of flow regimes and gas holdup in the presence of positive and negative surfactants in a non-uniformly aerated bubble column

2011 ◽  
Vol 66 (18) ◽  
pp. 4047-4058 ◽  
Author(s):  
Elena M. Cachaza ◽  
M. Elena Díaz ◽  
Francisco J. Montes ◽  
Miguel A. Galán
Keyword(s):  
Bubble Column ◽  
Flow Regimes ◽  
Gas Holdup ◽  
Unified Study

Hydrodynamic Flow Regimes, Gas Holdup, and Liquid Circulation in Airlift Reactors

1998 ◽  
Vol 37 (4) ◽  
pp. 1251-1259 ◽  
Author(s):  
Mohamed E. Abashar ◽  
Udi Narsingh ◽  
Andre E. Rouillard ◽  
Robin Judd
Keyword(s):  
Flow Regimes ◽  
Gas Holdup ◽  
Hydrodynamic Flow ◽  
Liquid Circulation ◽  
Airlift Reactors

Bubble Column with Electrolytes: Gas Holdup and Flow Regimes

2009 ◽  
Vol 48 (17) ◽  
pp. 8237-8243 ◽  
Author(s):  
Sandra Orvalho ◽  
Marek C. Ruzicka ◽  
Jiri Drahos
Keyword(s):  
Bubble Column ◽  
Flow Regimes ◽  
Gas Holdup

scholarly journals On the Design of Bubble Columns Equipped with a Fine Pore Sparger: Effect of Gas Properties

2018 ◽  
Author(s):  
Athanasios G. Kanaris ◽  
Theodosios I. Pavlidis ◽  
Ariadni P. Chatzidafni ◽  
Aikaterini A. Mouza
Keyword(s):  
Gas Phase ◽  
Gas Flow ◽  
Transition Point ◽  
Bubble Column ◽  
Flow Characteristics ◽  
Physical Property ◽  
Gas Holdup ◽  
Low Density ◽  
Wide Range ◽  
Phase Properties

In our previous works we have proposed design equations that can predict with reasonable accuracy the transition point from homogeneous to heterogeneous regime as well as the gas holdup and the mean Sauter diameter at the homogeneous regime. The validity of the proposed correlations was checked with data obtained using different geometrical configurations and several Newtonian and non-Newtonian liquids as well as the addition of surfactants. However, in all the experiments the gas phase was atmospheric air. This work investigates the effect of gas phase properties by conducting experiments employing various gases (i.e., air, CO2, He) that cover a wide range of physical property values. Experiments revealed that only the use of low-density gas (He) has a measurable effect on bubble column performance. More precisely, when the low-density gas (He) is employed, the transition point shifts to higher gas flow rates and the gas holdup decreases, a fact attributed to the lower momentum force exerted by the gas. In view of the new data, the proposed correlations have been slightly modified to include the effect of gas phase properties and it is found that they can predict the aforementioned quantities with an accuracy of ±15%. It has been also proved that CFD simulations are an accurate means for assessing the flow characteristics inside a bubble column.

scholarly journals Gas Phase Back-Mixing in a Mimicked Fischer-Tropsch Slurry Bubble Column Using an Advanced Gaseous Tracer Technique

2018 ◽  
Vol 17 (2) ◽  
Author(s):  
Lu Han ◽  
Ibrahim A. Said ◽  
Muthanna H. Al-Dahhan
Keyword(s):  
Gas Phase ◽  
Bubble Column ◽  
Gas Holdup ◽  
Axial Dispersion ◽  
Bubble Columns ◽  
Bubble Column Reactor ◽  
Tracer Technique ◽  
Solids Loading ◽  
Slurry Bubble Column ◽  
Gaseous Tracer

Abstract An advanced gaseous tracer technique and procedures were developed and executed to study for the first time the axial dispersion of the gas phase in a slurry bubble column reactor (SBCR) using air-C9C11-FT catalyst. Residence time distribution (RTD) curves were obtained by measuring the pulse-input’s response of the gaseous tracer. The gas phase axial dispersion coefficient (Dg) was obtained from minimum square error fit of the one-dimensional axial dispersion model to the measured tracer response data. The effects of solids loading on the axial dispersion of gas phase and the overall gas holdup have been studied. It was demonstrated that increasing solids loading improves the gas axial dispersion while decreasing the overall gas holdup. This work suggests that gas phase axial dispersion is significant in reactor performance evaluation of bubble columns or slurry bubble columns.

scholarly journals The role of radiolysis in the modelling of C2H4O2 isomers and dimethyl ether in cold dark clouds

2020 ◽  
Vol 500 (3) ◽  
pp. 3414-3424
Author(s):  
Alec Paulive ◽  
Christopher N Shingledecker ◽  
Eric Herbst
Keyword(s):  
Gas Phase ◽  
Dimethyl Ether ◽  
Recent Observation ◽  
Cosmic Ray ◽  
Thermal Method ◽  
Dark Clouds ◽  
Ice Surface ◽  
Dust Grain ◽  
Complex Organic

ABSTRACT Complex organic molecules (COMs) have been detected in a variety of interstellar sources. The abundances of these COMs in warming sources can be explained by syntheses linked to increasing temperatures and densities, allowing quasi-thermal chemical reactions to occur rapidly enough to produce observable amounts of COMs, both in the gas phase, and upon dust grain ice mantles. The COMs produced on grains then become gaseous as the temperature increases sufficiently to allow their thermal desorption. The recent observation of gaseous COMs in cold sources has not been fully explained by these gas-phase and dust grain production routes. Radiolysis chemistry is a possible non-thermal method of producing COMs in cold dark clouds. This new method greatly increases the modelled abundance of selected COMs upon the ice surface and within the ice mantle due to excitation and ionization events from cosmic ray bombardment. We examine the effect of radiolysis on three C2H4O2 isomers – methyl formate (HCOOCH3), glycolaldehyde (HCOCH2OH), and acetic acid (CH3COOH) – and a chemically similar molecule, dimethyl ether (CH3OCH3), in cold dark clouds. We then compare our modelled gaseous abundances with observed abundances in TMC-1, L1689B, and B1-b.

Sign in / Sign up

Export Citation Format

Share Document