Heat transfer characteristics between the immersed heater and the bed were investigated in a pressurized gas-solid fluidized bed of 0.15m ID and 3.58m in height. Effects of operating pressure and temperature and gas flow rate on the local and overall immersed heater-to-bed heat transfer coefficient were examined. The increase of operating pressure can contribute to the thermal stability of the pressurized gas-solid fluidized bed. The local heat transfer coefficient increased and approached a almost constant value along with the height in the heater zone, and the convergence occurred more early with an increase in the pressure. The overall heat transfer coefficient increased with increasing operating temperature and pressure, but it exhibited its maximum value with the variation of gas flow rate. The heat transfer coefficient was well correlated in terms of dimensionless groups as
N_u=0.083P_r^0.33P_d^0.08
N_u=0.105P_r^0.31R_e^0.11