Compressed air energy savings on an iron production plant

The South African economy has experienced several challenges in the past few years. One of the major causes of this was the lack of electricity supply. For many years the state owned electricity supplier Eskom, did not carry out any infrastructural upgrades. This led to the demand for electricity exceeding the supply. Initiatives, such as load shedding and Demand Side Management (DSM) projects, were implemented. Along with these, the price of electricity was increased significantly. Due to this, a number of industries started to suffer. One such industry was the South African steel making industry. Although the international steel industry also experienced problems Chinese import steel became cheaper than South African steel making it difficult for them to remain competitive. These two factors had a large, negative impact on the steel industry thus, a way to reduce operational costs had to be found. Energy saving initiatives were considered as a possible solution. In this paper, an energy saving initiative was implemented on the cold blast air system of a blast furnace. The identification and implementation was based on a methodology developed during this study. It was found that the cold blast supply pressure could be reduced by 20 kPa to achieve an approximate saving of 1.3 MW. This translates to an electricity cost saving of approximately R 8 million per year. This cost saving can be used to implement additional energy saving projects and increase the total cost savings. The cost savings contribute to the reduction in the operational cost of an iron production plant.