Análise da eficiência energética em fornos de fusão de ferro em uma fundição do Paraná

Abstract

Electrical energy accounted for one of the main inputs in the foundry industry, with the melting process representing the largest share of production energy consumption. In this context, improving energy efficiency became a relevant strategy for reducing operating costs and increasing industrial competitiveness. This study aimed to analyze the energy efficiency of the iron melting process in a foundry located in the state of Paraná, Brazil, by identifying improvement opportunities and evaluating their technical and economic feasibility. The research was characterized as an applied case study with a quantitative approach. Operational and energy consumption data from three induction furnaces were analyzed throughout 2025, using the specific energy consumption, expressed in kilowatt-hours per metric ton of molten metal, as the main performance indicator. In addition, on-site inspections were conducted to validate the collected data and identify energy losses associated with the characteristics of the metallic charge. The results showed that the foundry achieved an average specific energy consumption of approximately 708 kWh/t, which was lower than the industry average reported in the literature (796.3 kWh/t), although still above the benchmark value considered representative of best practices (538.1 kWh/t). Improvement opportunities were identified, mainly related to scrap oxidation, low bulk density of the metallic charge, and sand adhered to the return channels. Based on these findings, the implementation of a return material processing system using a runner breaker was simulated, resulting in an estimated 12% reduction in energy consumption, average monthly savings of BRL 13,097.80, and annual savings of BRL 157,173.64. The economic analysis indicated a positive Net Present Value of BRL 11,325.84 and an Internal Rate of Return of 14.87% per year, confirming the economic feasibility of the proposed investment when compared to the Minimum Attractive Rate of Return established by Selic estimated at June 2026 (14,5%). It was concluded that the adoption of metallic charge preparation practices contributed to reducing electrical energy consumption and operating costs, demonstrating that energy performance assessment constitutes a strategic tool for improving efficiency and competitiveness in foundry operations.