Abstract:
Ternium, located in Rio de Janeiro-Brazil, has two blast furnaces with an average daily production of 7500t each. The load distribution inside the blast furnace is carried out by the equipment that make up the top. Ternium's blast furnace top model is the bell-less top, in which a rotating chute transmission coupled to a gearbox is used to discharge the load in any region in radial direction. Due to the normal temperature and particulate matter of the process, this gearbox is cooled by a water circuit, lubricated by a centralized system, internally pressurized with nitrogen and protected from thermal radiation by a refractory. In blast furnace 1, the beginning of the loss of this protective refractory was identified, causing a localized temperature increase and a high risk of the set becoming blocked. Due to this risk mapped for this equipment of crucial importance to the process, this work was started with the objective of replacing the refractory in a maintenance stoppage, without replacing the entire set – which would entail high costs and considerable time of furnace downtime. With this, a platform was developed, installed on top in a preventive stop, and the necessary refractory was inserted, thus guaranteeing operational continuity.