Influence of Alcohol Addition on Liquid-Phase Volumetric Mass Transfer Coefficient in an External-Loop Airlift Reactor with a Porous Plate

2009 ◽  
Vol 42 (10) ◽  
pp. 713-719 ◽  
Author(s):  
Toshiro Miyahara ◽  
Naoki Nagatani
Keyword(s):  
Mass Transfer ◽  
Liquid Phase ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Porous Plate ◽  
Airlift Reactor ◽  
Volumetric Mass Transfer Coefficient ◽  
External Loop

scholarly journals Numerical study of the hydrodynamics and mass transfer in the external loop airlift reactor

2021 ◽  
pp. 34-34
Author(s):  
Predrag Kojic ◽  
Jovana Kojic ◽  
Milada Pezo ◽  
Jelena Krulj ◽  
Lato Pezo ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Airlift Reactor ◽  
Volumetric Mass Transfer Coefficient ◽  
Cfd Model ◽  
Gas Velocity ◽  
Liquid Mass ◽  
External Loop ◽  
Liquid Mass Transfer

The objective of this study was to investigate the hydrodynamics and the gas-liquid mass transfer coefficient of an external-loop airlift reactor (ELAR). The ELAR was operated in three cases: different inlet velocities of fluids, different alcohols solutions (water, 0.5% methanol, 0.5% ethanol, 0.5% propanol and 0.5% butanol) and different concentration of methanol in solutions (0%, 0.5%, 1%, 2% and 5%). The influence of superficial gas velocity and various diluted alcohol solutions on hydrodynamics and gas-liquid mass transfer coefficient of the ELAR was studied. Experimentally, the gas hold-up, liquid velocities and volumetric mass transfer coefficient values in the riser and the downcomer were obtained from the literature source. A computational fluid dynamics (CFD) model was developed, based on two-phase flow, investigating different liquids regarding surface tension, assuming the ideal gas flow, applying the finite volume method and Eulerian-Eulerian model. The volumetric mass transfer coefficient was determined using CFD model, as well as artificial neural network model. The effects of liquid parameters and gas velocity on the characteristics of the gas-liquid mass transfer were simulated. These models were compared with appropriate experimental results. CFD model successfully succeed to simulate the influence of different alcohols regarding the number of C-atoms on hydrodynamics and mass transfer.

Research on Mass Transfer Coefficient Measurement Model of External-Loop Airlift Reactor

2012 ◽  
Vol 512-515 ◽  
pp. 2405-2411
Author(s):  
Qian Wu ◽  
Ma Lin Liu ◽  
Tong Wang Zhang
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Measurement Model ◽  
Airlift Reactor ◽  
Continuous Stirred Tank Reactor ◽  
Volumetric Mass Transfer Coefficient ◽  
External Loop ◽  
Coefficient Measurement

A mathematical model considering the inter-phase mass transfer both in the down-comer and the riser of an external-loop airlift reactor was established in this paper. The calculated global volumetric mass transfer coefficient based on the assumption of continuous stirred tank reactor (CSTR) was different from the local volumetric mass transfer coefficients by the newly proposed mathematical model and the difference was discussed. The effects of mass transfer in the down-comer, the hydrodynamic pressure and the experimental time on the mass transfer coefficient measurement model have been studied in detail. And it was also proved that only the global volumetric mass transfer coefficient, but not the local volumetric mass coefficient, can be obtained from a time-concentration curve in the external-loop airlift reactor.

scholarly journals Ozone absorption in a mechanically stirred reactor

2007 ◽  
Vol 72 (8-9) ◽  
pp. 847-855 ◽  
Author(s):  
Ljiljana Takic ◽  
Vlada Veljkovic ◽  
Miodrag Lazic ◽  
Srdjan Pejanovic
Keyword(s):  
Mass Transfer ◽  
Liquid Phase ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Plug Flow ◽  
Operating Conditions ◽  
Volumetric Mass Transfer Coefficient ◽  
Pseudo First Order Reaction ◽  
Ozone Absorption ◽  
Stirred Reactor

Ozone absorption in water was investigated in a mechanically stirred reactor, using both the semi-batch and continuous mode of operation. A model for the precise determination of the volumetric mass transfer coefficient in open tanks without the necessity of the measurement the ozone concentration in the outlet gas was developed. It was found that slow ozone reactions in the liquid phase, including the decomposition of ozone, can be regarded as one pseudo-first order reaction. Under the examined operating conditions, the liquid phase was completely mixed, while mixing in a gas phase can be described as plug flow. The volumetric mass transfer coefficient was found to vary with the square of the impeller speed. .

Relation between Volumetric Mass Transfer Coefficient and Power Input per Unit Volume for Converging-Diverging Tube Airlift Fermenter

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Tapan K Ghosh ◽  
Bimal C Bhattacharyya
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Unit Volume ◽  
Hydrodynamic Characteristic ◽  
Power Input ◽  
Volumetric Mass Transfer Coefficient ◽  
External Loop ◽  
Airlift Fermenter ◽  
Uniform Tube

A conventional external loop uniform tube airlift fermenter (UT-ALF) was modified to improve its performance. The riser part was replaced by a converging- diverging tube. The newly developed reactor system is named a converging-diverging tube airlift fermenter (CDT–ALF). The modified bioreactor (CDT–ALF) provides a unique hydrodynamic characteristic. Empirical correlation was developed to determine KLa with respect to power input per unit volume. The modified system (CDT-ALF) shows 250% higher KLa compared to conventional one.

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