The gas-liquid mass transfer behavior of syngas components, H-2 and CO, has been studied in a three-phase bubble column reactor at industrial conditions. The influences of the main operating conditions, such as temperature, pressure, superficial gas velocity and solid concentration, have been studied systematically. The volumetric liquid-side mass transfer coefficient k(L)a is obtained by measuring the dissolution rate of H-2 and CO. The gas holdup and the bubble size distribution in the reactor are measured by an optical fiber technique, the specific gas-liquid interfacial area a and the liquid-side mass transfer coefficient k(L) are calculated based on the experimental measurements. Empirical correlations are proposed to predict k(L) and a values for H-2 and CO in liquid paraffin/solid particles slurry bubble column reactors.