Exergy relations in manganese production: Modelling the submerged arc furnace
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A model of the ferromanganese submerged arc furnace was purposed to yield valuable information for exergy calculations. A deeper understanding of at what point exergy is lost in the furnace might yield valuable information for the further optimization of the ferromanganese smelting process. The model is split into two parts covering the coke bed zone and the pre-reduction zone respectively.The coke bed zone model uses the estimated electrode tip position, mass transfer from pre- reduction zone, electric energy input and energy transfer to heat and chemical reactions as parameters. Hot gas ascending from the coke bed will enter the pre-reduction zone and exchange heat and mass (reaction) with the solid particles in the pre reduction zone.In the pre reduction zone model, the shrinking core model is applied to cover the reduc- tion kinetics of the ore particles. Moreover the Boudouard reaction is included and also decomposition of carbonates. Heat is exchanged with the furnace walls and the gas exits the furnace at the top. Unfortunately the model did not get to start working before the time was up for the work on this thesis. Nevertheless a sound foundation with derivations is given for the time this work should be continued.Matlab®is used for the calculations of this model. Thermodynamic data was programmed into Matlab to be easily available at any time for the calculations. Programs are written to take care of isolated parts of the problem to be used when their services are needed.The application of solid state thermoelectric devices on the outer shell of the furnace has the advantages of recycling otherwise lost energy, and in the process increasing the overall exergetic efficiency of the smelter. An additional advantage is the interpretation of the power output from the elements as heat flux, possibly replacing todays heat flux measure- ments.