REDUCTION OF OXYGEN CONSUMPTION IN A BLAST FURNACE THROUGH THE IMPROVEMENT OF HEAT EXCHANGERS EFFICIENCY

This paper concerns the performance improvement study of three heat exchangers. The objective is to reduce the consumption of oxygen used to enrich the blown air into a Blast Furnace through the improvement of the energetic efficiency of these heat exchangers. A CFD (Computer Fluids Dynamics) model was developed in order to simulate the thermodynamic behavior of the fluids inside the heat exchangers. Some geometric modifications were simulated with the objective of change the combustion gases flow characteristics. The simulation showed a potential of energetic efficiency improvement of 15,25%, which means an increase of 115 degrees C in the outlet air temperature. The simulated modifications were implemented in one of three heat exchangers and the actual temperature increase was 135 degrees C. After the implementation of the modifications in the others heat exchangers, the expected reduction of the oxygen consumption in the Blast Furnace is about 4.400.000 Nm(3) per year.