Study of heat transfer in a tubular-panel cooling system in the wall of an electric arc furnace

• Published in: Applied thermal engineering 2019-02, Vol.148, p.43-56
• Main Authors: Contreras-Serna, Josué, Rivera-Solorio, Carlos I., Herrera-García, Marco A.
• Format: Article
• Language: English
• Subjects: Arc heating; Cooling; Cooling losses; Cooling systems; Correlation analysis; Electric arc furnace; Electric arc furnaces; Flow distribution; Furnaces; Heat convection; Heat transfer; Heat transfer coefficients; Mathematical analysis; Outlet flow; Panels; Parametric analysis; Pipes; Piping; Slag; Slag-layer thickness; Surface energy; Temperature; Temperature distribution; Temperature gradients; Thickness; Walls; Water flow; Water temperature; Water-cooled panels
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2018.10.134

•Development of a model of the cooling system of an Electric Arc Furnace (EAF).•Heat transfer effects due to arc height and slag-layer thickness were studied.•Temperatures of water-cooled panels due to flow distribution were determined.•Different EAF operating ranges were analyzed and compared with experimental data. Most electric arc furnaces (EAF) use tubular panels as cooling systems to protect their walls from the impressive heat generated inside. This study focuses on heat transfer in the pipe-cooling systems of EAF walls. A model that considers surface-energy balances between different layers of the EAF’s walls and the heat radiated onto the walls by the electric arc and the molten-slag surface is developed herein. The temperature distribution is determined for the tubular panels, and the heat transfer is calculated. A total of 14 tubular panels covered the walls; the total water-flow distribution, together with the heat-transfer coefficient (HTC), is determined for each panel using a parallel-pipe network with conventional correlations for piping. The study is conducted via a parametric analysis in which the principal factors governing the process—the arc coverage and slag-layer thickness adhering to the walls—are varied. The results are compared with experimental measurements of the outlet water temperature. The experimental data are within the results that were obtained with the model, allowing us to estimate the operating conditions of the furnace. Moreover, the panels under the EAF’s highest and lowest temperatures are observed. Ideal operating condition is observed for the case wherein the arc is completely covered, the maximum thickness of the slag is 4.5 cm, the temperature difference between the inlet and outlet flow is 3 K, and the heat transferred by the wall cooling system is 3.35 MW energy losses reduced up to five times. We concluded that each panel has a different temperature and heat-removal capacity, which are highly dependent on the flow within it and its geometry, there is a difference of 3% in the water flow for the panels with lowest flow against those with higher. We show that slag-layer thickness and arc-coverage factors significantly affect the safe operation of the EAF, as well as its energy efficiency.