Abstract:It is an important measure to recovery and utilize the waste/residual heat resource of sintering-cooling process in cogeneration system for modern iron and steel enterprises nowadays. In the paper, the key problems and causes of recovery and utilization of sintering waste heat were analyzed firstly, and then the method and technique of “grade recovery and cascade utilization(GRUC)” was put forward according to the first and second laws of thermodynamics. The waste heat is recovered in grades according to the quality firstly, and then different qualities of residual heat recovered are utilized in cascades. The higher-temperature part of sinter cooling waste gas is used for power recovery, the medium or lower-temperature parts are used for direct thermal utilizations, such as drying and preheating of sinter mixture, combustion-supporting for ignition, hot-air sintering and so on. It is notable that the waste heat should be satisfied for the direct thermal utilizations first of all. In addition, the key problems of GRUC were researched. The results show that flow-rate of cooling air and height of sinter layer are main influencing factors on the recovery and utilization of waste heat; Moreover, the leakage of sintering-cooling system is another aspect influencing waste heat recovery and utilization.