Article ID Journal Published Year Pages File Type
688345 Chemical Engineering and Processing: Process Intensification 2012 10 Pages PDF
Abstract

The present work is an attempt to conserve energy in coal based sponge iron industry incorporating certain design modifications without disturbing the process technology. A typical sponge iron plant has been investigated to find out the potential areas where energy is being wasted. To recover heat from these areas two design modifications, Case-1 and Case-2, are proposed. Case-1 accounts for preheating of air using waste gas exiting from ESP. However, for Case-2 initially water is heated using hot sponge iron exiting rotary kiln and further hot water is used to preheat air. To compute coal demand of modified designs a model is developed based on heat of reactions, feed preheating, sensible and radiation losses, etc. Preheating of air up to 170 °C for Case-1 reduces coal consumption by 8.7%. Consequently, waste gas generation reduces by 16.7%. Thus, for Case-1 profit is Rs 9.6 million/year. However, for Case-2 preheating of air to 80 °C before entering the kiln reduces coal and water consumption by 7.2% and 96.3%. Consequently, cooling tower capacity is reduced by 37.2%. Due to 27.8% less profit for Case-1 in comparison to Case-2 Case-1 offers higher payback period than that of Case-2. Thus, Case-2 is selected as best proposed design.

► Present work deals with two design modifications proposed for sponge iron plant. ► First design accounts for preheating of kiln air using waste gas exiting from ESP. ► For second design water is heated using hot sponge iron to preheat rotary kiln air. ► A model is developed to compute coal demand of process based on different factors. ► For each modification economic and operability analyses are presented.

Related Topics
Physical Sciences and Engineering Chemical Engineering Process Chemistry and Technology
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