This paper reports the results of heat transfer of calcined petroleum coke and heat exchange tube. The unsteady heat transfer 3D model of single calcined petroleum coke particle layer was set up. The model had been used to investigate detailed heat transfer pathways. The calculated values of calcined petroleum coke temperature showed good agreement with the corresponding available experimental data. The temperature distribution, the heat quantity, the heat flux and the heat transfer contribution rate were studied with different heat transfer times. The results showed that the temperature of the particles near the heat exchange wall decreases rapidly in the early stage of the heat-transfer process, but the temperature of the particles far from the heat exchange wall is almost unchanged. the heat change process can be divided into high-speed stage, fast stage and slow stage. The average heat transfer contribute rate of solid phase is 92.79% and greater than that of gas phase. The contact heat conduction between particles is dominant at any position of the particle layer. The unconventional heat transfer direction distribution was found at the beginning of the heat transfer process. The detailed heat transfer mechanism of calcined petroleum coke and heat exchange tube was clarified. (C) 2018 Elsevier Ltd. All rights reserved.