Gas-solid flow in a pipe with different configurations (vertical, horizontal, and inclined positions) is studied experimentally. Air with temperature around 170 degrees C and sand particles with mean diameter of 253 mu m are used as gas and solid mediums, respectively. Effects of different parameters (pipe slope and solid particles feed rate) are studied on heat transfer rate between gas and solid particles. The Nusselt number decreases at lower solids feed rate in a dilute regime of the mixture; however, it increases at higher solids feed rates. Furthermore, results show that a higher Nusselt number takes place at the angles closer to 45 degrees.