Abstract: The effects of process variables on the heat transfer between an immersed heating element surface and solid/liquid mixture were investigated in a bubble column of 98mm i.d. The reactor was fitted with an axially mounted immersed heater which was made of copper with 20mm od and 120mm long. In order to simulate the system of the slurry phase FischerTropsch synthesis, the three phase system was composed of nitrogen, paraffin liquid, quartz sand of mean particle diameter 53μm,110μm,180μm or Fe2O3 powders less than 63μm. Process variables were examined in the following range: superficial gas velocity 0.005m/s～0.08m/s, temperature 353K～453K, pressure 0.1MPa～0.8MPa and solids concentration 0～20%. Three types of gas distributor were used in this study. A dimensionless correlation for the heat transfer coefficient is obtained by the leastsquare regress and presented as follows: St=0.179(ReFr)－0.25Pr－0.66. It fits the experimental data with an average deviation of 18% and can be applicable to both a gasliquid and a gasliquidsolid system with small particle less than 100μm.