(494g) Experiments on Bubble Behaviors in Three Phase Internal-Loop Airlift Reactor Using Optical Fiber Probe Measurements

Experiments on bubble behaviors in three
phase internal-loop airlift reactor using optical fiber probe measurements

Yongxiang
Gao, Haoran Lu, Youwei Cheng^*, Lijun Wang and Xi Li.

Department of Chemical and
Biological Engineering, Zhejiang University, Hangzhou 310027, PR China

The internal-loop airlift reactor has been gathered widely interests
because of its simple structure, high efficiency of mass and heat transfer,
good solid suspension and good mixing. A gas-liquid-solid three phase internal-loop
airlift reactor combined with a conical bottom and a nozzle inlet was
investigated deeply in term of its fluid dynamics in bubble-scale, besides in
column-scale. The bubble behaviour was implemented by optical probe method. The
image analysis was also carried out to validate the results. The data collected
by the optical probe was processed in time and frequency domain analysis via
MATLAB algorithms. The time domain analysis obtained dispersion parameters,
such as the local gas holdup, the bubble rise velocity, and the bubble chord
length distribution, and the frequency domain analysis revealed chaotic
characteristics. The maximum entropy method was utilized to transfer the bubble
chord length distribution (CLD) to bubble size distribution (BSD). The effect
of the superficial gas velocity and solid concentration on the bubble
behaviours in the riser and downcomer regions were discussed carefully. The
reasonable agreement between the two measured methods certified and supplied a
feasible method to predict the bubble behaviours in gas-liquid-solid three
phase fluidized beds. The bubble behaviours in this work can be a benchmark for
CFD simulation verifications for airlift reactor, and these in return can
provide important guidance for reactor design and scale-up.