Gas-liquid mass transfer coefficient for methanol synthesis was determined in a mechanically agitated slurry reactor with paraffin oil as the inert liquid medium and n-hexane as the supercritical medium. The ratio of gas-liquid mass transfer resistance to reaction resistance increased with increasing of catalyst concentration under the reaction condition of temperature 238℃

syngas pressure 3.7 MPa

and space velocity 2744 h-1. As gas-liquid mass transfer was the control step

gas-liquid mass transfer coefficients were obtained by extrapolation. Catalyst concentration had a much bigger effect on gas-liquid mass transfer of CO than that of CO2. Gas-liquid mass transfer coefficients of CO and CO2 in the liquid-phase reaction were 0.161 s-1 and 0.03 s-1 respectively

while they were 0.199 s-1

0.042 s-1 under supercritical condition. Supercritical fluid is conductive to gas-liquid mass transfer in the three-phase methanol synthesis process.