ENERGY AND EXERGY ANALYSIS OF GRATE-KILN-COOLER PROCESS USED FOR INDURATION OF IRON ORE PELLETS

摘要

Although many models of iron ore pellets induration have been established and improved on the basis of the first law, the exergy-based analysis of the grate-kiln-cooler (GKC) process is rare. Therefore, exergy balance test was systematically carried out on a GKC plant in China. And according to the test, energy and exergy analysis has been conducted to investigate the irreversibilities of the process. The energy analysis shows that the largest energy losses resulting from the exhaust gas enthalpy, and the ones associated with water evaperation and grate are relatively large. On the other hand, the exergy analysis reveals that the largest exergy destruction associated with the heat transfer irreversibility, and the one resulting from combustion irreversibility is really quite large. Especially, the duplex macrostructure of the partially oxidized pellets has been discoverd in the final product. Further, some suggestions on how the processes could be improved have been posed specifically. This study provides a better understanding of the energy and exergy flows of iron ore pellets induration in the GKC plant. The findings of the present study can further be applied to perform process optimization to maximize the cost-effectiveness of iron ore pellets induration production by the plant.