Objective
Modern application of well established techniques of smoke abatement in an electric arc furnace for special steels resulting in electric energy savings of 30 kwh/t. Decrease of electrode consumption and lower maintenance costs.
The most obvious advantages offered by this project are : reduction of energy consumption, reduction of electrode consumption, increasing of furnace output, improvement of yield with reference to the tapped steel, reduction of suspended dirt in the environment, reduction of noise near the furnace outside the snuff-box, lower maintenance costs for the snuff-box, better rationality of the smoke collection system (direct advantage), use of poor charging scrap (oleate turnings).
In this analysis the following parameters were monitored :
energy consumption, electrode consumption, refractory consumption (furnace and roof), maintenance costs, furnace output yield (with reference to the tapped steel), oxygen consumption, quantities of developed smoke and noise in the environment (near the furnace).
With the furnace smoke collection plant it has been possible to manage the smoke collections.
The use of large oxygen quantities blown into the furnace has allowed a remarkable productivity increase with consequent operational savings.
Furnace productivity increased from 39 t/h in January 1981 to 45 t/h in August 1981 thanks to the large use of oxygen during melting down. Satisfactory energy savings have been achieved : the specific consumption decreased from 615 kWh/t in the first months of 1981 to 570 kWh/t.
Electrode consumption decreased from 6.8 kg/t in January 1981 to 5.72 kg/t. This was as a result of running the electrodes from 620 v for the first and second bucket during the melting-down stage, and operating the furnace at a higher pressure.
The yield of tapped steel appears to be of good quality. No measurements of suspended dust in the steel-shop have been carried out but visually considerable improvements have been noted. The operators were fully satisfied with the improved environmental conditions, both from the point of view of atmospheric pollution and of safety (splashes and flashes from the furnace). Noise measurements near the furnace (at the plancherside, 7 m from the stuff-box) and in front of the furnace (casting bay) have shown a 10 db reduction in the frequency range 50-10,000 Hz.
Maintenance costs in real terms have remained the same since the improvements. It is obvious that the extreme furnace processing temperature, due to the oxygen, has caused high refractory roof consumption making it necessary to install a water cooled roof to reduce this consumption.
A new smoke collection system (snuff-box) will be installed on the 150 ton electric arc furnace erected in the teksid steel works. The furnace is equipped with water-cooled wall panels and with a framework made of strong structural shapes onto which sheet-panels are mounted so forming a hood that can completely enclose the furnace.
This snuff-box is equipped with travelling shutters to enable scrap charging and the ladle is approached from under the furnace by means of a car. This ensures the maximum handling and accessibility of the whole plant whilst having the advantage of keeping the smoke and dust produced by the furnace when in operation inside the hood. In this way environmental and working conditions are greatly improved. Even the solidified slags are removed using a vessel on a truck with approaches the furnace from underground.
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DEM - Demonstration contractsCoordinator
10022 Carmagnola Torino
Italy