DC Electric Arc Furnace

Capital cost is comparatively less to DC EAF as there is no requirement for a rectifier and its controls.

Generates less amount of higher order harmonics, hot iron metal can be directly charged as raw material.

Keeping the power electrical common, two separate shells can be used continuously for production

The operation is more stable than the DC EAF electric arc furnace. The melting is uniform.

It has reduced electrode consumption because of the system regulations. Electrode consumption is reduced to around one-third. However, there is a need to improve the spalling and cracking of the electrodes. Lower consumption of electrodes makes it possible to make low-carbon heat.

It has lower lining wear. Refractory consumption is less on the side walls but more on the bottom. Overall saving in refractory consumption is in the range of 15 % to 25 %.

There is convection stirring in the bath.

The temperature distribution of the bath is better than the DC EAF. Better temperature distribution results in improved heat distribution. The hot spots on the furnace wall in the case of AC-EAF are not there.

Noise levels are much lower than the DC EAF (reduced from 105 dB to 85 dB).

Installation costs are higher than the DC electric arc furnace (around 10 % to 35 % more).

Operating costs are lower than the DC electric arc furnace (around 15 % to 20 % less).

There is less network disturbance. There is a sharp reduction in the flicker effect. Flicker level and flicker frequency are reduced by half. The need for Var compensation equipment is much lower.

There is lower energy consumption than the DC EAF. There is a 5 % to 10 % savings in power.

Bottom electrodes make the furnace bottom complicated.

It has lower levels of dust and gas emissions.

PLC controls have a high degree of automation, fast heating speed, and stable and reliable production rhythm.

According to customer requirements, the smelting process can be set arbitrarily without stopping, achieving different control schemes of constant power, constant current, constant impedance, and constant voltage, which is convenient and fast.

Voltage regulation on load and current regulation without polarity. During the smelting process of the DC EAF, the voltage level can be increased or decreased arbitrarily without stopping the machine as required. The current is accurate to every 1 ampere and can be increased or decreased arbitrarily.

During the smelting process of the DC arc furnace, the polarity of the positive and negative electrodes can be arbitrarily changed, resulting in a uniform furnace temperature, effectively solving the defect of uneven temperature inside the furnace caused by the anode effect, the arc length of the DC electric arc furnace can be adjusted arbitrarily without power outage as needed. It can be used for both submerged electric arc furnace and open arc smelting, and various materials can be melted to achieve a 2-in-1 composite multifunctional use (electric arc furnace+submerged arc furnace).

The main control board of the DC EAF power supply has a soft start function to avoid the phenomenon of damaging the electrical components of the thyristor due to high voltage impact upon startup. This board has a photoelectric isolation function, which can effectively prevent strong magnetic fields from interfering with the stability of the control circuit during the production process. The board also has overvoltage, overcurrent, phase loss, and high-temperature protection functions, which can effectively avoid damage to the equipment caused by short circuits.

The centre temperature of the DC electric arc furnace electrode is high, with concentrated heat, making it easy to deeply bury the electrode, and the furnace bottom is not easy to rise, making it more suitable for smelting products with high melting points.