Furnace combustion and control renovation to improve the productivity of a continuous annealing line

The investigated annealing line was constructed in late 1980s with a design capacity of 350,000 t/y. After many years of service the annealing furnace was in an unsound state and renovated in a number of steps in three years time. A furnace survey was firstly conducted to fingerprint the conditions of the combustion system and to identify opportunities for improvement with a quick return of investment. Burner tests were carried out to better understand the combustion process and identify the critical conditions for component design and improvement. Furnace mathematical model was developed to study the energy balance and deficiency of the process. The model was further explored in the designing and implementation of a new control automation system using Model Predictive Control. Production results over the recent years were collected and analyzed. The data after the renovation showed some significant improvements with a reduced specific energy consumption below the benchmark of World Steel Association, a 4% increase in monthly production throughput, over 10% increase in production volume and an advance to a highly automated process.