The systems are designed to intensify the melting process in electric arc furnaces EAF and other melting furnaces. Systems of intensification of melting provide additional heat input in the electric arc furnace, heating and melting of scrap metal, oxygen lancing and feeding of powdered materials.
The modern concept of development of steelmaking provides for the transition of steelmaking units from multiple-slag to single-slag processes when the melting unit produces an intermediate, and the steel is produced in the “ladle-furnace” unit. Such technique involves melting with the use of modern intensification systems.
Currently, there are quite a few methods of intensive smelting in electric furnaces: input of additional heat from natural gas combustion (or other fuel) at the stage of charge melting (wall oxy-fuel burners, oriel oxy-fuel burners, manipulated window oxy-fuel burner, etc.), slag foaming technology (injection of carbon-bearing powder), scrap metal preheating (scrap metal heating units), accelerated melting through intensification of oxygen blowing of the melt on the oxidation stage (oxygen lances).
The Jet Technologies’ systems of intensification of melting allow comprehensive implementation of various methods of intensification of melting. The company produces all necessary equipment, including:
- Window, oriel, wall and other oxy-fuel burners;
- Window, oriel, wall and other oxygen lances;
- Injectors for powdered materials, powder feed tubes;
- Manipulators for oxy-fuel burners, lances and injectors;
- Powder feeders;
- Valve stands, gas control units, etc.;
- Water-cooled copper elements;
- Water-cooled furnace elements;
- Automated control systems of intensification of melting.
In addition, the specialists of Jet Technologies Concern have developed a device that combines in a single piece an oxy-fuel burner, oxygen lance and powder injector. The new device was named MULTIFURMA (multi-nozzle tuyere). All the technical innovations used in the multi-nozzle tuyere are protected by numerous copyright certificates and patents. The development of the multi-nozzle tuyere yielded several important advantages:
- a reduced size of the multi-nozzle tuyere and, as a result, the reduced size of the copper panels, simplification of their construction and a simplified design of the furnace wall panels;
- enhanced design reliability of the multi-nozzle tuyere, enhanced heat protection and reduced amount of water required for cooling;
- in addition to operating in the capacity of an oxy-fuel burner, oxygen lance, and powder injector, the multi-nozzle tuyere allows to combine these modes, i.e. to simultaneously operate as an oxy-fuel burner and supply oxygen through the blow-off nozzles, blow oxygen and feed powder, and etc.
- the combination of the three devices in one multi-nozzle tuyere provides new opportunities for its use in the operating window on the manipulator.
The multi-nozzle tuyere is a water-cooled multitubular aggregate with a multi-nozzle copper block (copper head). The special nozzles are designed to form jets of an assigned structure. The well-tested and meticulously controlled manufacturing technology allows to produce high resistance heads that retain the geometry of the nozzles throughout their service life.
The systems of intensification of melting in electric arc furnaces are the most effective during the integrated use of stationary multi-nozzle tuyeres (wall, oriel) and a window multi-nozzle tuyere installed on a manipulator. A window multi-nozzle tuyere installed on a manipulator can move in the working window and, having all the advantages of a stationary multi-nozzle tuyere, allows:
- to service a wide area around the furnace door, up to 50% of the total volume of the furnace.
- to cut massive pieces of scrap on the spot and inject carbonaceous powder into the furnace bath through the gaps in the scrap metal before it is completely melted, creating foamy slag at early stages of melting.
- to receive a high extent of oxygen enrichment over 90% in a wide range of consumption and intense mixing of the melt without emissions;
- to ensure the lowest percentage of metal loss during oxygen lancing, as moving of the multi-nozzle tuyere during lancing does not lead to an intense local peroxidation of the melt.
Feeding and adjustment of working mediums to the means of intensification of melting is performed from the valve stands. The feeding of carbon powder is performed using a powder feeder.
The automated control system is performed on the basis of a programmable industrial controller. The reliable design ensures long-term durability, ease of operation and maintenance.
The use of the Jet Technologies’ systems of intensification of melting ensures the following technical and economic effects:
- Reduction of melting time;
- Reduction of power consumed for melting;
- Reduction of consumption of electrodes for melting;
- Bath foaming and creation of heat-insulating slag;
- Precise refining of molten metal to the required carbon content.
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