HYDRAULIC TRANSPORT OF ABRASIVE SOLIDS: THE AIR-LIFT PUMP

Although the air-lift pump has been superseded by submersible pumps in raising water from wells and mines, it still provides an attractive means of lifting abrasive slurries because, unlike mechanical pumps, it has no moving parts to wear. However, current design of air-lift pumps must rely on empirical equations, or, at best, incremental computer solutions. Design is complicated by the fact that relative velocities of the phases change over the whole pump length. A new design equation is developed to predict the lift of an air-lift pump, given the flowrates of air, liquid and solid in the pump, and the dimensions of the air-lift tube. The new equation is baaed on well-established multiphase flow theory, and offers significant advantages over current design techniques. In combination with an equation for the overall pump efficiency, the new equation provides a method for optimizing the design parameters for the air-lift pump.