Energi- och exergiflöden i stålframställningsprocesser vid
SSAB Tunnplåt AB i Luleå
Energy costs are high nowadays and that is the reason why the energy consumption needs to become as small as possible in most of the companies. To accomplish the small energy usage one needs to map the energy flows, study them and monitor them. One method that can be used for this is energy balance calculation. The method gives an opportunity to separate different energy flows and see where each flow is heading. There is also another method which is more advanced than energy balance calculation. This method is called exergy balance calculation: it contains everything of the energy balance calculation and also takes the quality of energy into account. Calculation of exergy gives a possibility to estimate how effective a system is in terms of energy consumption and to find deficiencies which is the basic motivation for improvements. The purpose with this Master's Thesis is to study the energy flows within the scope of amount and quality at SSAB Tunnplåt in Luleå, Sweden. The purpose is also to create a model which can be used in energy and exergy balance calculations for different processes at the ironworks. The realization of this assignment included problem investigations as well as literature surveys. The processes at the ironworks were analyzed. The system boundaries were defined. An extensive data collection was made. The balances were created with help of thermodynamic relations. And a model in the form of a spreadsheet was made. The finished model, which is derived in this report, was tested for a typical winter month. The results from this calculation are shown in the report as an example of the model usage. The result is also compared with a similar study from 1989.