Many people know that arc furnaces consume a large amount of electricity, but few understand the reasons behind it. Today, we asked a vacuum consumable arc furnace manufacturer to explain why arc furnaces have high power consumption.
- Raw material conditions
In electric furnace steelmaking, scrap steel is used as the main raw material. Because the scrap often consists of light and thin materials or compressed blocks, it is easy for the furnace charge to become too high during charging, leading to heat loss and temporary shutdown. If the first charging is insufficient, a second charge is required, and in some cases even a third charge. Each extra charging cycle (average charging time around 5 minutes) increases power consumption by about 7–12 kW·h per ton. In addition, if carbon and phosphorus content is found to be high after melting and refining, the oxidation period needed for removal requires a longer time and higher energy consumption.
- Operator skill level
The melting stage accounts for 60%–70% of total power consumption, with most energy wasted after the bath is fully melted. A common issue occurs during the phosphorus removal stage in oxidation. Blind slag removal leads to excessive lime usage and significant energy waste.
- External objective limitations
During smelting, sudden power restrictions or blackouts may occur due to power shortages. If the interruption lasts too long, the molten steel cools and solidifies, requiring remelting afterwards, which wastes a large amount of energy.
- Other unexpected incidents
For example, if an operator mishandles equipment and causes an electrode to break, a large amount of heat is lost while fixing it. If a sample taken during the reduction period shows that the chemical composition does not meet requirements, a second oxidation process is needed, wasting additional heat energy. During smelting, if a coal-oxygen burner leaks water, the assisting combustion stops; if material sticks to the furnace wall, the furnace lid must be opened to remove it. All these issues prolong smelting time and increase heat loss to varying degrees.