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

Pohang No.3 BF has been repaired it from February 24th to June 6th for 102 days. POSCO intend to improve operation efficiency and save costs by enlarging inner volume from 4,350 to 5,600m3. The relining criterion are that remaining of hearth refractory, wear of body shell, needs for increasing production and so on. Recently, the most critical point among them is the remaining of hearth refractory considered minimum remaining is 600mm. Although, the remaining of Pohang No.3BF hearth refractory is about 900mm, relining was needed for wear of body shell by high productivity. The strategies for extending blast furnace campaign life are described. First, switching body cooling system. The body cooling system is changed from copper stave to dense cooling plate which was adopted design criteria for the thermal and mechanical wear mechanism and applied same to Gwangyang No.1BF and Pohang No.2BF. POSCO’s design concept could be minimize the wear of the blast furnace even at the high productivity. Second, the improvement of main shell profile. The main shell profile was changed belly, throat, hearth diameter, bosh and shaft angle, inner volume and so on. Last, change in refractory design. According to the heat load of furnace body, refractory design was adopted to maximize the cooling ability and minimize the cost. In addition, the design of the refractory block of tap hole was changed from 3block to 2block in order to prevent leaking of the molten Iron. In addition, new measuring instrument were installed in the blast furnace proper to monitor the gas distribution, segregation fines distribution and deformation of body shell. First, We installed Acoustic gas temperature measurement system that monitor the circumferential distribution of gas flow inside the Blast Furnace. We can change the charging mode using that system. Second, We installed Profilemeter. Profilemeter can measure the segregation fines distribution according to the charging mode. Finally, FBG sensor was installed that check the crack on Hearth Shell. Also it is possible to manage to melting iron level.