Modelling of the iron ore production at LKAB - Validation and process optimization

Examensarbete för masterexamen
Master Thesis
Jakobsen, Hampus
Scott, Alexander
LKAB is a state owned, Swedish mining company that produces iron ore products for the steel making industries, mainly iron ore pellets. The final process of heat treating iron ore pellets, which is done in a Grate-kiln, is the most energy consuming part of the refining process. This has led to a collaboration between LKAB and the Division of Energy Technology at Chalmers to make the Grate-kiln more energy efficient. With help from an in-house simulation model by LKAB, earlier work within this collaboration has suggested process changes that makes this process more energy efficient. The simulation model describes the heat and mas transfer through the whole Grate-kiln process. The simulation model is believed to perform well under standard running condition, but has difficulty to evaluate the process when large changes are made in the running settings. Therefore, this work has been to validate the simulation model against an experimental test rig, so called pot furnace, where it was the grate performance from the Grate-kiln that was analysed. Measurements were taken from the pot furnace and compared with the calculations from the simulation program. The key parameters and processes used for comparison were the temperatures, the degree of oxidation, the drying process and the pressure drop. The outcome from this study has shown that the results from the simulation model regarding the oxidization process correlate with the measured results from the pot furnace. Temperature measurements from the pot furnace showed a lower value than the simulation model due to the limitations in the pot furnace. Pressure drop is well calculated, but it is concluded that either mismeasurements regarding the pellets in the pot furnace occur or that the simulation model overestimated one or several variables. The drying process has been proved to be the most difficult parameter to predict by the bed model. This partly due to the regulating process in the pot furnace and also calculation faults in the bed model. From this study, further work should focus on these parameters when evaluating the bed model. It should also focus on comparing the simulation model with a new developed pot furnace and also the full scale Grate-kiln process.
Energiteknik, Energy Engineering
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