The hydrodynamic characteristics of RFJLB was studied with superficial liquid velocity (UI), nozzle diameter (Dn) and nozzle height (Hn) in the range of 0.0293-0.094 m/s, 17.4-22.0 mm and 50-400 mm, respectively. For Dn = 17.4 mm, Hn = 50 and 200 mm, with ejector mode and regular operating procedure i.e. simultaneous entry of gas with increasing liquid velocity, had limitation of not establishing the circulation loop. To overcome this limitation a modified operating procedure i.e. entry of gas after established liquid circulation loop is proposed. Also the comparison of gas holdups with ejector and injector mode proves the effectiveness of ejector mode and can eliminate the supply of compressed gas. Thus proper choice of Dn, Hn and also the operating procedure becomes necessary. (C) 2012 Elsevier Ltd. All rights reserved.