Reducing both Fuel Consumption and GHG Emissions: A Retrofit Concept for a Dravo-Lurgi Iron Ore Induration Furnace
R. Pomalis, L. Zheng, T. Herage, E. Godin ,
A study was carried out by CanmetENERGY and ArcelorMittal to investigate the feasibility of reducing fuel consumption and GHG emissions in a Dravo-Lurgi induration furnace using a flue gas recirculation scheme. By retrofitting and operating the furnace in this manner the convective rates within the furnace could be mostly maintained at typical operating levels while substantially reducing the excess air requirement. Modification of the furnace in this manner significantly improves the thermal efficiency of the unit thereby reducing fuel consumption and improving GHG emission.
In this project computer simulation was performed on three different flue gas recycle scenarios using an AspenTech HYSYS model built by CanmetENERGY and an in-bed model called SIMBOUL, developed by COREM in conjunction with ArcelorMittal which models the bed and predicts product quality. The computer simulation was validated using extensive plant operating data and field measurements from two induration machines at ArcelorMittal’s plant in Port Cartier, Quebec.
It was found that significant fuel saving could be achieved with many of these retrofit options. One option rendered a reduction of 51 % of the stack gas flow and a 16 % fuel saving. Since these units are fuelled using both No. 6 oil above the pellet bed, and coke breeze contained within the pellet, this meant that 46 % of No. 6 fuel oil use could be avoided. Results from the SIMBOUL model suggested that while the major product quality indices remain unchanged, the average product discharge temperature increases with many of the options and this concern needs to be further examined.
