MODULETECHNOLOGY
26 27 MODULE TECHNOLOGY OXYGEN, CARBON AND LIME SIDE WALL INJECTION TECHNOLOGY FOR ELECTRIC ARC FURNACES CONCEPT The MODULE TECHNOLOGY: state-of-the-art chemical energy package for electric arc furnaces, combines a variety of fixed injectors and related control devices (i.e.: valve stands, carbon/fluxes dispensers, automation system and Human Machine Interface). Injectors add chemical energy by exothermic reactions, post-combustion control and foaming slag optimization to improve the overall EAF performances and to reduce transformation costs. MOCA CARBON DISPENSER GASEOUS FUEL VALVES STAND AUTOMATION SYSTEM EAF INJECTORS OXYGEN VALVES STAND MOLI LIME DISPENSER CHARACTERISTICS M-ONE OXYGENJET HI_JET LIMEJET The equipment on board of the EAF shell can be made-up of four different injectors. Each has been developed to satisfy a very specific requirement of the melting/refining process: M-ONE for supersonic oxygen lancing and carbon injection into the slag OXYGENJET for supersonic oxygen lancing LIMEJET for lime/dololime injection into the slag HI_JET for deep injection of fines (carbon, aluminum, lime, DRI fines, bag house dust) into liquid steel/slag interface Increased oxygen efficiency and carbon recovery Injectors nozzles do not clog Increased metallic yield Increased productivity Improved foaming slag conditioning Improved metallurgical process control Improved overall operating efficiency Improved process gas emission Reduced fuel usage Reduced electrical energy usage Reduced power-on time Reduced conversion costs
28 29 M-ONE OXYGENJET HI_JET LIMEJET This multipurpose injector puts the EAF chemical energy utilization into a new dimension. This innovative injection tool allows extremely high recovery of injected carbonaceous fuel, melting process flexibility and consistency, metallurgical control and environmental improvements. Oxygen and carbon lances are embedded in the same body. This kind of design improves the injection efficiency, reduces the amount of injectors installed on the EAF shell and delivers a very light tool to handle (30 kg/ 66 lb) for easy maintenance operations. Because the carbon injection is placed so close to the oxygen supersonic stream, carbon fines are accelerated thus improving carbon recovery when compared with traditional carbon lances. M-ONE features the same supersonic oxygen nozzle design used in the OXYGENJET. This injector consists of a supersonic-coherent oxygen stream lance to guarantee the optimal penetration of oxygen in the liquid steel for C oxidation and other oxidizing reactions in the steel/slag interface. MORE has developed a Method of Characteristics with Boundary Layer Correction Code to design the Axisymmetric Supersonic Nozzle. Nozzles designed with this code are practically shockfree, with static pressure at the exit section that perfectly matches the ambient pressure (the maximum pressure difference between the supersonic stream of oxygen and the ambient is only 0.04 bar) and the streamlines parallel to the injector axis. With this design, the coherency of the oxygen stream is maintained over a long distance to guarantee the optimal deep bath penetration. This innovative injection tool allows for extremely high recovery of injected carbonaceous fuel, melting process flexibility and consistency, metallurgical control and environmental improvement. MORE has developed a specific nozzle whit which the carbon fines are shrouded by a coaxial stream of supersonic oxygen that accelerates the fines 10 times more than a traditional carbon lance. Fines are then able to penetrate the slag and reach the liquid steel. This injector consists of a lime/dolo-lime lance to inject the lime/dolo-lime fines into the slag for V ratio and temperature steady control. Lime/dololime fines can be shrouded by oxygen/ gaseous fuel to avoid fines build up in front of the tip.
30 31 MIXED SWIRLED FLAME FLASH STOP MSF BURNER TECHNOLOGY BACKFIRE PREVENTING SYSTEM FOR SIDE WALL BURNERS AND INJECTORS All MORE injectors work as highly efficient oxyfuel burners for heating and assisting melting of scrap after each scrap bucket charge. The flame makes use of the innovative Mixed Swirled Technology (MSF). CONCEPT CONCEPT The injectors can generate a flame of oxygen - fuel. A specific research project has been performed to improve combustion and heat transfer efficiency to the scrap surface. The result is a MSF (Mixed Swirled Flame) optimized for each type of injector. The particular burner tip design dramatically improves the mixing of reactants and prevents the generation of a cold flame. The adjacent images show the temperature field of a premixed and swirled oxyfuel flame. When cold scrap lies in front of the injector, unmixed oxygen can flash back and damage the injector and/or adjacent furnace water cooled panels. To avoid this side effect, the reactants need to be ignited as close as possible to the injector tip. The MSF configuration develops a very hot flame close to the injector, improves flame stability and its heat transfer ability, especially to the scrap located in the injector area. The MSF significantly helps to minimize the risk of unburned fuel flowing through the scrap pile producing endothermic reactions by cracking. Extremely high flame temperature Optimum mixing of gasses and combustion Improved heat exchange with scrap pile Mixed Swirled Flame Stable and hot flame close to the injector tip Traditional axial diffusion flame Blue colored cold flame due to the poor mixing of oxygen and natural gas The FLASH STOP system has been developed to prevent accidental damages due to oxygen and fuel backfiring in the copper front face, injector tip and water cooled panels caused by the presence of a thick piece of heavy scrap in front of the injector tip. The system is made up of two temperature sensors embedded directly into the copper element to continuously detect the variance of the copper temperature. In case of a backfiring, the temperature on the front panel will rapidly increase over the alarm threshold. Then, the automation system will automatically reduce the burner power or switch-off the injector. As soon as the temperature returns to its normal value, the system will turn on the injector again. Increased life time of burners and copper blocks Higher burner efficiency Added safety by reducing water leakages inside the EAF Reduced maintenance man-hours
32 33 INSTALLATION MORE designs, manufactures and supplies a wide range of solutions to find the best position of the injectors inside the EAF shell, avoiding damages from scrap falling and reaching a correct geometrical configuration. TECHNOLOGY MORE copper bulged blocks are made from extruded and drawn copper slabs that guarantee exceptionally high thermal conductivity avoiding all the usual problems related to cast copper parts (i.e embedded impurities or cavities). Copper and steel welding is done by MORE's highly qualified welders. CNC COPPER BULGED BLOCKS The objective of MORE s quality policy is to guarantee the best levels of customer satisfaction by providing products with an excellent quality/price ratio. To improve both the reliability of our products and reduce the production costs, MORE has invested in state of the art CNC machining and turning centers. With this vertical level integration, MORE produces 100% of its copper elements in-house, which guarantees a high level of production and precision and quick delivery of spare parts. Increased lifetime compared to ordinary cast blocks Shorter lead times compared to traditional cast blocks Optimal heat transfer capacity and reduced heat overload Copper faces are designed for simple on-site replacement (steel to steel welding) Sturdily built resist to heavy mechanical impacts Tailor made design Extruded cooper slabs CNC machining FEATURES Optimized panel design to minimize cracking tendency Bulged block can be designed with different geometries according to customers requests Extruded copper slabs with high-density, high temperature resistance and strong resistance to fatigue and good thermal conductivity to fatigue and good thermal conductivity Welding Final product