Abstract:In laboratory gaslift loop reactors, the gas flow rate for generating critical suspension of solid particles,Q_c, was measured in order to assess the energy efficiency for suspending solids. Three loop reactors were installed with bottoms of different shapes, and can be operated in two modes: either upflow or downflow in the central draft tube. Tap water, ion-exchange resin and fine gold ore concentrate were used as liquid and solid phases respectively. The study was focused on the effect of deflecting baffles fitted on the lower end of the draft tube. The results of measurement indicated that deflecting baffles near the bottom promoted swirling liquid flow over the bottom, led to significant reduction (50%~90%) of Q_c and improved suspension of solids. The advantages of lower energy consumption and better solids suspension by installing deflecting baffles may benefit the general commercial processes in chemical, biotechnological and metallurgical industries.

Key words: loop reactor　deflecting baffles　swirling flow