CSN BLAST FURNACE #3 OPERATION DURING ITS SECOND CAMPAIGN OPERATIONAL IMPROVEMENTS FOR SAFE HEARTH LIFETIME

摘要

CSN is the largest steel company in Brazil. Its production capacity is 6 Mt a year of crude steel. It is located in Volta Redonda, Rio de Janeiro State, Southeast Brazil. CSN steel plant has two blast furnaces in full operation: BF#2, with 1653 m~3 inner volume and 4237 m~3 inner volume for BF#3. Currently, BF#3 is in its third campaign and its last blow-in was August 7, 2001. Its first campaign lasted from May 1976 to August 1984 and produced 15,700,743 t in 3,390 m~3 inner volume. Its second campaign was conducted from January 1985 to April 2001, in 3,815m~3 IV. During BF#3 second campaign many improvements either on equipment, process control, burden distribution, cast house practice and raw material control were made. By that time we started natural gas injection and increased oxygen enrichment in 1986 and started coal injection in 1997. The total hot metal produced in the second campaign was 43,387,484 t. Many works have been done in this blast furnace hearth during its second campaign in order to guarantee its safe lifetime. A small repair took place around its four tap holes in 1996 and strict operational controls have been introduced from this year until the blow-out in May 2001. Details about operational control like casthouse practice improvements, process control changes, practice of loading and injection of titanium ore, small hearth repair and others improvements and changes to guarantee its safety lifetime are presented in this paper.