SMARTFIRE – Reducing energy consumption in steel mills
The reheating process in steel mills prepares metal stock, such as steel plates for hot rolling by heating them to a target temperature. The hot steel can then be deformed by successive sets of rolls to achieve the desired final size and shape.
However, reheating is an energy-intensive process where the costly energy consumption of furnaces is of increasing concern as it also impacts on the environment and indeed, the profitability of steel mills.
Started in July 2005, SMARTFIRE was a 42 month Research Fund for Coal and Steel (RFCS) project that greatly enhanced reheating furnace operation, maintenance and product quality by improved diagnostics as well as better monitoring and control of process parameters. The consortium, which was coordinated by European steel producer Tata Steel, had partners in Spain, Germany, Sweden and the United Kingdom. In total, SMARTFIRE received some €1.2 million in funding from the European Commission.
Specifically, SMARTFIRE developed a real-time diagnostics and performance analysis tool to improve combustion efficiency and temperature regulation in the actual furnace. The project also saw the build up of residue on the reheated metal stock being reduced significantly. "The project team developed an innovative flame analysis system capable of detecting burner operating parameters such as firing rate, excess air levels and pollutant emissions, but also established a combustion and furnace diagnostic system utilising process databases to furnish statistical and physical models" said project coordinator, Graham Andrews of Tata Steel.
The resulting DWS (Diagnostic, Warning, Suggestions) system takes advantage of the accumulation of process data generated by modern furnace control systems. Such data includes many measurements such as furnace zone temperatures, gas and air flows, and stock details, but not in a form that can be easily interpreted to provide useful and timely information on furnace performance. The DWS is effective in that it can monitor such issues as fuel use, air-to-fuel ratio, furnace zone temperatures and energy distribution. Qualitative evaluations of the SMARTFIRE results have been carried out and are impressive. The consortium has reported net energy savings of between 1 and 3%, scale reduction of some 4% as well as yield and quality improvement due to better temperature regulation.
According to Andrews, the benefits of SMARTFIRE can contribute to Europe's competitiveness due to associated energy savings, increased quality and productivity. "Any fuel energy and cost savings will be accompanied by reductions in emissions such as carbon dioxide. These savings also increase profitability and help protect jobs," he says.
The knowledge acquired in the project can be easily shared with the entire reheating furnace area of the European steel sector. "A set of recommendations relating to the diagnostic components and system design has been disseminated to our partner companies wishing to develop their own DWS system," concludes Andrews.