An experimental investigation was carried out to determine the thermal performance of a heat exchanger operating with vertical upflow of a hot gas loaded with solid particles. Using particles having mean diameters (88-157 μm), the inlet gas velocity was varied from 1.5 to 13 m/s and the inlet temperature was varied from 100 to 600°C. This resulted in mixture densities of 2.0 to 30 kg/m3for the gas-solid flow.