Hydrodynamics of a pilot plant bubble column (0.3 m dia, 4 m height) was investigated in the temperature range 30-160 degreesC and pressure range 0.2-1.1 MPa for the nitrogen-cyclohexane system. The dry gas flow rate was varied in the range 0.02-0.11 kg/m(2) s. The geometry of distributor was also changed. The measurements of bubble size distributions along column axis and mean gas holdup in the column were made. From these results the interfacial area and bubble swarm velocity were calculated. The results obtained have been compared with correlations described in the literature.