Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

An air lifting system together with a hydraulic pumping system is well known as a commercially merited lifting system owing to convenient operations and maintenances. In the past, an air lifting system was used to lift corrosive and/or toxic liquid on land, so the main matter of concern was how the submergence ratio of the liquid in a vertical pipe affects the two phase air-liquid flow state. Recently, various kinds of factors including air injection point have been recognized more important than the submergence ratio, because the technology can be applied to lift polymetallic manganese nodules in the state of air-liquid-solid three-phase mixture from the seabed about 5,000 meters below the sea level. In this study, a lab-scale air lifting system with vertical height 3.6 meters was designed and manufactured to investigate the flow transfer characteristics of the air lifting technology. Then, the experiments of the three-phase air-liquid-solid flow in vertical tubes were performed by changing the air injection point, tube diameter, air injection rate, size and density of solid particles, and injection rate of solid particles. From the results, it was confirmed that these factors have great effects on the efficiency of the air lifting system.