Calculation and Analysis of the Relationship Between the Efficiency and Position of Electric Arcs and Power Consumption in Electric Arc Furnaces (EAF) of Smaller and Larger Capacity. Part 2. Calculation and Analysis of the Relationship Between Position of Arcs, Walls and Power Consumption

Resumo

The power consumed during the melting process by a small-capacity DSP-5 furnace was analyzed. For each melting stage, the arc efficiency values of DSP-5 furnaces and average arc efficiency of the melting process (η_AM = 0.57) were calculated. The arc efficiency of the small-capacity furnaces is considerably lower than that of the modern large-capacity DSP-120 furnaces (η_AAV = 0.78). One cause of the lower arc efficiency of the small-capacity furnaces during furnace charge melting and arc burning inside the wells is the small distance between the arcs and the lining of the furnace walls. Another cause of the lower arc efficiency of the small-capacity furnaces during the liquid-phase periods of the melting process is the large exposed portion of the arc, no deep arc immersion into slag, and no slag foaming in the furnace. The low arc efficiency of the small-capacity furnaces leads to a significant specific power consumption during melting (700–750 kW·h/t), which is 1.9 to 2 times greater than that of the modern DSP-120 furnaces (375 kW·h/t). By using slag foaming devices in the small-capacity furnaces, it becomes possible to increase the average furnace arc efficiency of the melting process to η_AM = 0.72–0.74, while reducing the specific power consumption during melting to 400–420 kW·h/t.