Study on the performance of a 200 m airlift pump for water and highly-viscous shear-thinning slurry

Abstract An airlift pump facility of 200 m length was designed and constructed; pump experiments were conducted for water and two types of highly-viscous shear-thinning slurries. The primary objective of this study is to obtain quantitative data on the performance characteristics of slurries for deep-sea mining. Experimental results showed the capability of the airlift pump for the slurries. The airflow rates which give high discharge flow rates for the slurries were nearly the same with that of water. The difference in the viscosity of the working fluids was observed in the amount of the discharge flow rate. A simple simulation method to predict steady-state pump performance was also developed, and the results were validated by comparing with the present experimental results. For water, simulation results showed good agreement with experimental results. For the slurries, the simulations also showed good agreement for low airflow rate conditions. However, for high airflow rates, a discrepancy between the simulation and experimental results was observed. A reliable pipe friction model for gas-slurry mixtures in high Reynolds number region for the slurry with a small power index is required to improve the prediction accuracy of pump performance in large-scale airlift pumps.