Posted 28 Dec 2010 23:16
Short process of the modern method of electric arc furnace steelmaking wears compete with, in addition to the process itself has advantages, but also benefit from the electric arc furnace technology and equipment continue to improve, the electric arc furnace steel production of main economic indicators continue to refresh. Advanced equipment in all operating conditions has reached the scrap out of steel - a steel time 45min, power consumption of 300kWh / t level. Increase in the use of 30% against 50% reduction of hot metal or molten hot metal, the electric arc furnace to further improve product quality and shorten the refining time and lower power consumption, while increasing process flexibility. After a series of reforms, modern electric arc furnace technology with traditional electric arc furnace with very different equipment, steel-making process has become a large part of the ring - the beginning of refining. (1) of large-scale and high power. Electric arc furnace capacity is too small not only low productivity, and technical and economic indicators is difficult and refining, continuous casting and rolling equipment support, thus enlarging the furnace capacity is to improve the overall efficiency of production processes short effective means. Since the 70s of the 20th century, many countries have phased out 30 tonnes electric furnace, replaced by a large-capacity electric furnace. Accompanied by the increase in furnace capacity input power increases, tons of steel to the configuration of high-power transformer capacity, ultra-high-power direction. (2) Long operation and foaming slag submerged arc process. EAF increase the input power also increases the net energy loss of short, high voltage, low current operation is characterized by the reduction of the long arc power loss is quite effective. In order to avoid the long arc of radiation heat loss caused by the increase and on the lining, lid adverse effects of life in the melting process of foaming slag arc heat shield to improve the efficiency of the arc is very necessary. In addition, slag foaming during EAF also significantly reduce the noise. Electric arc furnace production of carbon steel and low alloy steel when the *** is easy to use oxygen to produce enough slag so that slag bubble CO gas, and in stainless steel smelting, the blowing agent is required by the thermal decomposition of carbonate produced CO2 gas **** to form slag. (3) improvement of electric equipment and DC power supply. Improvement of electrical equipment including electric arc furnace electrode automatic adjustment, electric arm and "an electric double oven," the configuration. AC arc furnace automatically adjust the electrodes to ensure balance and maximum power three-phase power input. Row with the use of exchange as compared to copper - steel or aluminum composite plate made of electric arm reduces the net resistance of the short, but also to make equipment more portable and easier to maintain. Alternate use of a double boiler shell power supply system, "an electric double oven" in the form to give full play to the efficient use of electrical equipment, significantly improve the electric arc furnace production capacity. Compared with the AC electric arc furnace, to avoid the three-phase arc power supply caused by the electrodes in the furnace "hot spots" and "cold zone", but also can reduce the flicker on the grid to reduce the consumption of the electrode surface oxidation. (4) The diversification of energy sources. Charge high water with carbon and oxygen lance using supersonic oxygen blowing to help strengthen the modern electric arc furnace melting heat generated by oxidation of elements in the total heat input of 1 / 3 of the fuel - oxygen lance burner can provide 10% to 20% energy input, which can significantly reduce power consumption. Power belongs to secondary energy, the use of a thermal power into electricity when the efficiency of coal by 30%, the energy converted to heat energy in the arc furnace efficiency of about 70%, melting scrap steel from coal to heat the total thermal efficiency of only 20 %, while the use of the direct combustion of fuel and oxygen to the heat generated by the thermal efficiency of melting steel scrap up to 40% or more. Can be seen in the arc furnace with coal, oil and natural gas, alternative energy power can increase a comprehensive energy efficiency. In addition, coal burner and oxygen lance to provide additional heat is also equal to the total input power increases. (5) combustion and scrap preheating. Enhanced due to the high allocation of carbon and oxygen blowing operation of large quantities of CO gas, combustion will be one of the chemical energy into heat, but also conducive to the safety of furnace gas emissions. However, due to the secondary combustion furnace can be converted to CO2 in CO about 30% of the heat transfer to the pool, it is necessary to recover scrap preheating furnace gas in the sensible heat. (6) Raw material diversification. In order to avoid recycling of scrap steel will scrap many of impurity concentration, the traditional furnace commonly used to charge about 10% of the income distribution of raw iron as a scrap substitute supplies. The use of modern electric steelmaking pig iron source in addition to the cold, there are direct reduced iron (DRI and HBI), hot metal, decarburization ferrite, iron carbide, composite metal materials. In particular the hot metal to take advantage of their carry large amounts of physical heat and chemical heat can shorten the refining time, lower power consumption and smelting costs. (7) Automation and intelligent. With the power input of the intelligent control system, expert system, focusing on technologies such as the use of control systems, automation and intelligent technology has greatly promoted the smelting technology to optimize the refining process operation, energy saving and provides greater convenience.