Dynamic natural gas control via architech solution

Synopsis: increasing the production rate of an Electric Arc Furnace (EAF) while also lowering overall cost can be a difficult challenge. The current situation at OneSteel in Australia is natural gas is less expensive than electricity to melt steel. The question then becomes how to use the natural gas efficiently. During the bore in and melting stages of the first and second buckets of scrap, the transfer of energy from the gas burners to the scrap metal is very high. Once the scrap has partially melted and a flat bath is obtained, the energy transfer drops dramatically. Determining the optimum time to turn off the gas burners to obtain maximum energy efficiency became the goal. GrafTech International's ArchiTech system can be used to measure electrical harmonics generated by the arc in the furnace. As the scrap is melted in the furnace, the harmonics generated decrease. OneSteel and GrafTech used this signal to develop a control loop to determine when to turn off the burners allowing them to maximize production rates. Power on time decreased, allowing for higher production rates and lower energy costs. Other consumables, such as graphite electrodes and refractory consumption should also decrease