EXPERIMENTAL STUDY ON CONVECTIVE COEFFICIENTS IN A SLURRY BUBBLE COLUMN

摘要

The main objective of this work was to determine the influence of gas and slurry velocities and solid load concentration on experimental convective heat transfer coefficients (h), for a three-phase suspension in cross flow around a square in-line tube array. Experiments were performed in a pilot scale equipment conformed by a column of square cross section. In the central part of this equipment there is a bank of 49 tubes with a S_T=S_L=4.4 cm. The system used was air, tap water and sieved sand at average particle diameter of 505 μm. The velocities of liquid and gas phases were varied from 0.28 to 0.60 cm/s and from 1.36 to 2.45 cm/s, respectively; and the solid load concentration from 0 to 30% w/w. The results allow to conclude that h for a three-phase system is larger than either for a two-phase or one-phase system. The presence of solid phase enhances the heat transfer, however, this increase is less evident for high values of solid concentration.