Three-phase airlift internal loop reactor:: correlations for predicting the main fluid dynamic parameters

Three-phase airlift loop reactors have many industrial applications. Examples include applications in the chemical, metallurgical, biochemical and minerals-processing industries; fluid dynamics in such systems is a critical factor affecting efficiency. The experimental work was carried out at a pilot-plant scale in a tank with a cylindrical shape and conical bottom (height 1.25 m; diameter 0.42 m), water and air were used as liquid and gas phases, and for different solid phases, different loads of glass spheres (diameters: 0.25 and 1 mm; density 2.6 g cm(-3)), and polystyrene cylinders (diameter and length 3 mm; density 1.0 g cm-3) were introduced. Air was injected through the bottom of the tank by means of 12 nozzles (diameter 1 mm each). An internal draft tube riser was tested on different configurations as its diameter was varied (44, 82, 125 and 240 mm) as was its height (1050 and 630 mm). Corresponding liquid velocities in the adjacent annular downcomer were determined by a thermal tracer technique, solid holdups were determined by conductivity methods, riser overall gas holdups were deduced from the liquid level, and riser gas holdup from manometer readings. Several adjusted correlations were considered in a method to predict the main fluid dynamic parameters (solids and gas holdups, and superficial liquid velocities). (c) 2005 Society of Chemical Industry