8th International Congress on Science and Technology of Ironmaking - ICSTI 2018

In operational practice of the iron ore sintering machine, the increasing air leakage ratio will cause the higher electricity consumption of the suction fan, the higher solid fuel rate, the lower sinter productivity, and the worse sinter quality. In general, more than 50% of the leakage occurs at the pallets themselves and the interfaces between the pallets and the wind boxes. Basically, the sintering strand is comprised of a large number of pallets. And, it leads to the larger number of sealing parts. Consequently, the routine examination of the sealing condition of the pallets for detecting any abnormal air leakage is quite heavy load for the maintenance staffs. Hence, an on-line continuous measurement technology on the air leakage ratio of the sintering machine has been developed in China Steel Corporation (CSC). It has been applied to help the maintenance staffs easily and effectively find out the abnormal air leakage, then to repair or replace the pallets in the very short time. In this technology, the hot-wire type anemometers are fixed on a moving rack for scanning the velocity of the effective air flowing through the sinter bed. Meanwhile, the microphones are installed beside the pathway and close to the outer sidewall of the travelling pallets for monitoring the sound pressure generated by the abnormal air leakage. For identifying the passing pallet, the thermal-resistant type RFID technology is adopted. Based on the data measured from the hardware system mentioned above, the air leakage ratio of the sintering machine can be calculated with the mass balance method and total gas flow rate drawn by the suction fan. And, the pallets with abnormal leakage can be detected and ranked in the severity of leakage according to the measured sound pressure with the relevant criteria, This technology had been implemented in the CSC No. 2 sintering plant since August, 2016. The operation result indicates that it can effectively reduce the air leakage ratio by 5% and further decrease the electricity consumption of the suction fan for the sintering machine. In fact, this technology is very helpful to maintain a low air leakage ratio during the long-term operation of sintering machine.