Efficient use of waste energy in the steel industry

In this study, the potential to use waste energies from the steel production at SSAB Strip Products Division is investigated. SSAB Strip Products Division is a leading producer of high strength steel. SSAB Strip Products Division in Lulea produces 2.3 million tonnes of crude steel every year. The study is based on energy balances in the different production lines. The energy balances are then investigated with exergy balances in order to investigate the quality of the different energy flows. The study concludes that there is a great potential for increasing the use of waste energy at SSAB. Today many of these flows are pure losses that are cooled away or burnt. The total heat loss for the steel production in one year is approximately 2380 GWh or a total power of 272 MW. From exergy calculations it can be shown that the upper theoretical limit when converting the energy into high quality energy such as electricity is 950 GWh or 108 MW. The conclusion is that it is possible to recycle an impressive amount of energy. The technologies for this are briefly discussed concerning the ORC and Kalina cycle. Other solutions are also briefly investigated, for example one solution is to use waste heat in the district heating system and by doing so making it possible for the local power company to produce more electricity. Most data regarding these calculations were extracted from a local processing system and then stored in a model describing the plant. The calculations are presented in the result part in the form of tables and diagrams. This study does not consider if an investment is economical feasible, just that it has a great potential. The result may be used in further investigations that will address that problem.Validerat; 20101217 (root