Residence time distribution measurements in a two dimensional rectangular airlift reactor by digital image processing

In this work, a novel, relatively simple and accurate, as well as economically attractive technique based on image processing was introduced for determining Residence Time Distribution (RTD) curve in an airlift reactor. For this purpose, an impulse-response technique by injecting colored tracer was used in a two dimensional rectangular glass reactor with a working volume of 2400 cm3. Tap water and air were used as the operating fluids. The captured images at specified time intervals of 1.5 s were analyzed by the “ImageJ” software. The RTD data obtained by this new digital image processing procedure were compared with data obtained by classical colorimetric technique. The influence of different superficial gas velocities was investigated on hydrodynamic of mixing. The results showed that this quick-inexpensive technique yields to reliable data. This technique avoids the expensive probes and data acquisition systems that are imperative in other measuring techniques.