A Mass Transfer Experiment Using Deoxygenation and Aeration of Water

To demonstrate the phenomenon of mass transfer, an experiment was developed to measure the overall and individual mass transfer coefficients in the opposite processes of deoxygenation and aeration. Both these processes have practical applications in chemical, environmental and mechanical systems. Streams of N2 (deaeration/deoxygenation process) or Air (aeration/oxygenation process) were bubbled through a semi batch reactor containing water. The contents of the reactor were mixed using an external recirculating pump to provide uniform conditions of concentration in the reactor. The dissolved oxygen concentration in water can be reduced from the saturation limit of 8-9 mg/L at room temperature to 1-2 mg/L at the end of deoxygenation cycle. In the reverse process of aeration, dissolved oxygen concentration was raised from 1-2 mg/L to the saturation limit. Dissolved oxygen concentration, volume of aqueous phase, and flow rate and composition of incoming gas stream were continuously measured. Using appropriate mass transfer relationships, experimental data are analyzed for the determination of individual (kL and kg) and overall (K