Thermal and hydraulic performance of a three-phase fluidized bed cooling tower

An experimental study was made of the thermal and hydraulic characteristics of a three-phase fluidized bed cooling tower. The experiments were carried out in a packed tower of 200 mm diameter and 2.5 m height. The packing used was spongy rubber balls 12.7 mm in diameter and with a density of 375 kg/m³. The tower characteristic was evaluated. The air-side pressure drop and the minimum fluidization velocity were measured as a function of water/air mass flux ratio (0.4–2), static bed height (300–500 mm), and hot water inlet temperature (301–334 K).

The experimental results indicate that the tower characteristics KaV/L increases with increases in the bed static height and hot water inlet temperature and with decreases in the water/air mass flux ratio. It is also shown that the air-side pressure drop increases very slowly with increases in air velocity. The minimum, fluidization velocity was found to be independent of the static bed height.

The data obtained were used to develop a correlation between the tower characteristics, hot water inlet temperature, static bed height, and the water/air mass flux ratio. The mass transfer coefficient of the three-phase fluidized bed cooling tower is much higher than that of packed-bed cooling towers with higher packing height.