Studies on Energy Integration for Modification in Existing Sponge Iron Plant

Abstract

It is observed that the coal is the major source of energy for the Sponge iron plant and all energy conservation schemes will lead to a decreased consumption of coal. Based on the principles of process integration, the present work investigates operational modifications which can lead to efficient energy integration in a coal based Sponge iron plant being operated with SL/RN process. Energy can be conserved and optimized with different ways such as energy integrated with different units like heat exchanger, heat pump, regenerators, waste heat boiler and fluidized bed dryer. The present study leads firstly to identify amount of waste heat available in sponge iron process flow sheet. For energy conservation of plant, designing of fluidized bed dryer and a gas carrying duct are suggested. In this fluidized bed dryer, waste heat can be used as heating medium for moisture removal and preheat treatment of different raw material flow streams i.e. coal and iron ore streams. The production of sponge iron and waste gas 15.87 ton/hr and 91.78 ton/hr is computed through simulation of conventional plant data. Through these approaches consumption of coal and process air is reduced by 6.5% and 41.03% of that required in original process flow sheet. With this new proposal it is estimated that 59% of waste energy is utilized in FBD and these are cool down up to 172oC and emitted to environment through chimney.