Analysis, design and performance of bottom anodes of DC furnaces

摘要

It is well known that the operating thermal state of the anode of DC furnaces is critical to its lifetime. In this work, a three-dimensional unsteady-state heat conduction model has been developed to examine the operating thermal behavior of billet and pin type anodes from a knowledge of the main process variables and design parameters. Results of the model which are in the form of temperature evolution, for the metallic charge and for the furnace bottom, are in good agreement with measurements done in the 175 m.t. capacity DC finger shaft furnace of HYLSA's thin slab continuous casting plant. In the case of anodes with conventional billets the model has allowed a judicious selection of design, operating and repair conditions that moderate the thermal conditions to which the anodes are exposed. Henceforth, the anode life, in the shaft furnace, has passed from an average of 300 heats to more than 1900 heats. Additionally, the model enabled the conceptualization of a billet that has been implemented in the new DC twin electrode furnace of the plant. This new billet allows the anode to run much cooler than conventional ones thus resulting in a radical increase of its lifetime, close to 6000 heats.