optimizing chemical energy into electric arc furnaces

摘要

Modern Electric Arc Furnaces utilize significant amounts of chemical energy to lower the overall energy usage associated with the melting of scrap steel. Typically, between 30 to 50% of the total energy required is supplied from the chemical reactions with the steel, particularly, that associated with the oxidation of iron and silicon, and from natural gas burners. Utilizing the chemical energy effectively within the furnace is important to the overall energy efficiency of the furnace and the cost of operation. Researchers at Swinburne University of Technology have been working closely with engineers at OneSteel to (a) develop effective and practical models to predict energy consumption and how it is affected by various parameters and (b) form strategies to lower overall energy consumption. The models developed are based on thermodynamics with corrections for kinetics effects. Building on the models developed and previous work by Jepson, we developed relationships to predict how the cost of both electrical and chemical energy varied with meltdown time. These predictions were tested with plant trials and confirmed that cost savings greater than 3% could be achieved by using more natural gas in the early part of heat. The approach taken is quite general, that is, the modeling and cost analysis approach described in the paper could be applied to similar furnaces.