Abstract: In order to study the features of high temperature flue gas drying and rotating tube drying,the two processes were simulated using Aspen Plus.Energy balancing method and exergy analyzing method were employed to analyze the energy utilizing efficiency of these two drying systems.Results show that the Aspen Plus can accurately simulate the high temperature flue gas drying and rotating tube drying processes.When the flue gas temperature is 750 ℃ and the vapor temperature is 203. 1 ℃,the heat utilizing efficiency of rotating tube drying is 71. 27%,which is 4. 04% higher than the flue gas drying proces,while,the exergy utilizing efficiency of rotating tube drying is87. 68%,which is 49.33% higher than high temperature flue gas drying. The heat utilizing efficiency of high temperature flue gas drying and rotating tube drying will increase with the rising of temperature of drying medium. On contrast,the exergy utilizing efficiency will decrease with the increase of temperature of drying medium.