Grade Recovery and Cascade Utilization of Residual Heat in Sinter Cogeneration System

It is an important measure to recovery and utilize the 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 residual/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 residual 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 technologies of GRUC were researched. Finally, an application example of GRUC was carried out.