Investigating the possibility of a cost saving intervention on a blast furnace cold blast system

Due to the economic difficulties experienced in the South African steel production industry, possible production cost savings need to be considered. The Demand side management program and time-of-use (TOU) strategies implemented by Eskom, the electricity utility provider, is considered as a possible cost saving strategy. In this paper, the possibility of implementing a load shift on the compressed air supply to a blast furnace is investigated. The saving was estimated with a model and verified using a theoretical calculation. The model predicted a peak time electricity cost saving of 1 MW. The theoretical saving was calculated to be 920 kW. A strategy was proposed to the management of a blast furnace on a real-life steel plant to validate the feasibility. From the case study it was determined that the annual cost saving does not justify the risk of doing a load shift. The largest risk is blast furnace instability that could result in production losses. In conclusion it was found that a load shift cannot easily be done on a blast furnace. From the constraints identified, it may be feasible to further investigate a load shift in the Eskom morning peak alone.