Abstract:
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 the
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 the CFD and 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 the appropriate experimental results. The CFD
model successfully simulates the influence of different alcohols regarding
the number of C-atoms on hydrodynamics and mass transfer.
