“Blasting” level performance
4 April 2016
ArcelorMittal has upgraded one of its blast furnaces in Brazil with a level-monitoring solution that uses Sitrans LR560 devices. The metering solution provides the operators with detailed and reliable information that contributes to improved overall furnace performance.
ArcelorMittal, the world’s leading steel producer in many market segments, produces steel in 20 countries. In Brazil, ArcelorMittal is very active, with many production sites. One of them is located in Vitoria, in the state of Espírito Santo: ArcelorMittal Tubarão. This huge site delivers 7.5 million t of hot coils and steel slabs per year. ArcelorMittal Tubarão is a fully integrated steel production facility that started operations in 1983 and has been recognized for its excellence in equipment management. One example is the record-breaking Blast Furnace No.1, which worked for 28 years, producing 94 million t of hot metal in the same campaign. In 2012, the company carried out a revamp of Blast Furnace No. 1. The upgraded equipment would need to meet the highest technological standards and match or exceed the good results achieved to date.
Critical level measurement requirements
Flávio Gomes, an experienced engineer in charge of blast furnace maintenance, instrumentation, and control, describes the furnace: “Blast Furnace No.1 is a huge piece of equipment that produces around 10,000 t of hot metal per day, and the load it receives is heterogeneous (iron ore, coke, and flux) and is added in different steps from the furnace top. The operation is continuous and presents high temperatures (around 1,500oC) and pressures (up to 42kgf/cm ). The temperatures on the furnace top can reach 400 °C or more. One critical piece of information to guarantee stable operation is the raw material distribution on the top of the blast furnace during the charge. The distribution (layers) may be compared with the layers of a cake, and each layer must have a defined thickness. The main difficulty faced in this kind of measurement is reading the level profile at the end of each raw material batch charged inside the furnace and assembling all the layers, showing the real position and thickness of all the materials inside the furnace, because the raw materials are consumed all the time, at a nonconstant speed.”