Views: 2 Author: Site Editor Publish Time: 2022-06-15 Origin: Site
In the development process of electric furnace steelmaking, the ultra-high power three-phase AC electric furnace has greatly developed the electric furnace steelmaking production, and the electric furnace steel production has reached 40% of the world's total steel production, but also brought some problems, that is, the high-power AC arc has poor stability, has a large impact on the power grid, and has large noise pollution and other problems. Compared with AC furnace, what are the advantages and disadvantages of DC furnace?
1. The reactive power impact of the DC furnace on the power grid is small and the amount of harmonic generation is low, so that sometimes dynamic compensation devices such as TCR can not be installed (only filters are installed to compensate for harmonics). Even if Baosteel is equipped with an SVC compensation device, its capacity It is also much smaller than the AC furnace. In this way, the DC furnace has a high investment in the power supply system, but it saves money on the compensation device, so the investment will not be higher than that of the AC furnace.
2. The DC furnace still has advantages in reducing electrode consumption, reducing arc noise, and having a stirring effect on molten steel.
3. For DC furnace steelmaking manufacturers with many years of experience, the maintenance technology of power supply system and bottom electrode is no longer a problem. In this case, the production cost of DC furnace will still be better than that of AC furnace (electrode consumption, refractory consumption) and power consumption may be lower).
1. The most significant low-current long-arc operation realized by the DC furnace at that time can also be realized by the high-impedance AC furnace. Especially with the continuous progress and maturity of the high-impedance furnace technology, this advantage of the DC furnace no longer exists. .
2. The advantage of direct current furnace production cost has been weakened. Compared with high-impedance furnaces, the absolute value of reducing electrode costs is not large, and it is difficult to prove that DC furnaces have lower power consumption per ton of steel (previously, it was generally considered that the right has an advantage of 5~10kW·h/t).
3. After all, the DC furnace has a more complex power supply system, and its reliability is not as good as that of the AC furnace; and the maintenance of the electrode at the bottom of the DC furnace is troublesome, and there are unsafe factors, which make those unfamiliar manufacturers worry a lot.
4. The advantages of DC furnaces in reducing power grid pollution are usually reflected in the reduction of investment costs. For AC furnaces, in principle, as long as there are compensation devices (SVC, SVG) with sufficient capacity, the power quality of the power grid can generally be achieved. of the requirements.
5. The limitations of DC furnaces in stainless steel smelting are well known. The long arc problem is the same as that of high impedance furnaces (so it is generally considered that high impedance furnaces are not suitable for smelting stainless steel), but the addition of a bottom electrode in DC furnaces may lead to non-conductive problems. Another argument is that the alloy yield will decrease when the stainless steel is smelted in the DC furnace (the unidirectional current with the molten pool as the positive aggravates the transfer of alloy elements such as chromium to the slag phase).