Abstract: The bubble characteristics in the gas-liquid concurrent up-flow reactor and the effect of gas flow rate and liquid flow rate on the bubble Sauter mean diameter, bubble rising velocity and pressure drop was investigated. Results showed that the bubble Sauter mean diameter and bubble rising velocity both increased with increasing gas flow rate and decreasing liquid flow rate. The bubble diameter distribution and rising velocity distribution in the radial direction both increased with increasing radial distance firstly and then decreased. The pressure drop increased with increasing gas flow rate firstly and then decreased, but the effect of liquid flow rate on it was negligible. Through the dimensionless analysis of the experimental data, the relationship between the average diameter of bubble Sauter and the Reynolds number in liquid phase and gas phase was put forward.

Key words: up-flow reactor, gas-liquid distributor, bubble Sauter diameter, bubble rising velocity, bed pressure drop