Development and Application of a New Combination of Models to Improve the Uniformity of Ventilation and Exhaust in a 500 kA Potline

摘要

Three numerical models have been developed to investigate the thermal balance in a 500 kA aluminum reduction cell. The hooding efficiency, ventilation uniformity, and exhaust gas flowrate (EGF) uniformity of the cell were studied by using an upper cell thermoflow model and a dual-ductline flow model, and the effects of changing the EGF on the thermal balance were investigated using a slice thermoelectric model. The results of the models were compared with industrial measurements taken under similar conditions, revealing good agreement that demonstrates the validity of the use of numerical models to study the impacts of the EGF on the thermal balance. The cell showed a high hooding efficiency, good ventilation uniformity (deviation range - 4% to 5%), and more uniform thermal field when using the high-performance duct and dual-ductline system. The potline could exhibit good EGF uniformity (deviation range +/- 5%) in running cells. Through these advantages, the problems of dust accumulation in the duct and gas leakage at the tapping end (TE) were solved effectively, and the EGF was decreased from 10,607 Nm(3)/h to 8308 Nm(3)/h without reducing the cell hooding efficiency. The results were transferred to industrial practice by upgrading the duct system of a 500 kA potline, achieving a total energy saving of 233 kWh/t-Al, of which about 80 kWh came from the gas treatment center and 153 kWh from the reduction cells.