Air Stripping of Volatile Organic Compounds from Groundwater: An Evaluation of a Centrifugal Vapor-Liquid Contactor

The performance of a centrifugal vapor-liquid contactor equipped with high specific surface area packing (>2000 m²/m³) was evaluated for air stripping of jet fuel components from groundwater. Hydraulic test data indicated that the Sherwood flooding correlation which has been proposed for use in designing centrifugal vapor-liquid contactors overestimates the rotational speeds at which flooding occurs. For the mass transfer of performance, a concept of area of a transfer unit (ATU) was introduced to account for the change in fluid loading with radius of the packing torus. The ATU was found to be a strong function of the specific surface area of the packing and to a lesser extent a function of rotor speed and liquid flow rate. A correlation based on the specific surface area of the packing is proposed for predicting the ATU. A simple empirical model is also proposed for determining the power consumed in turning the packing torus at various operating conditions. Previous claims in the literature that centrifugal vapor-liquid contactor is resistant to fouling because of high shear force were found not to be valid for groundwater with high iron content.