Sintering: Most Efficient Technologies for Greenhouse Emissions Abatement

Abstract

The sintering process is finalized to transform the small grained raw material into larger grained iron ore sinter of the right dimensions to be used in the blast furnace. Achieving an adequate sintered product depends on the adequate raw materials supply and the previous stage to the sintering process, granulation. The air emissions comprise of various pollutants such as dust, SO2, NOx, CO, organochlorine compounds, heavy metals, etc. Atmospheric emissions also include volatile organic compounds (VOCs) formed from volatile material in the coke breeze, oily mill scale, etc. Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), commonly known as dioxins and furans, are also formed. Emission limits of the sinter waste gas have been continually and strictly tightened in the last years, so new solutions are continually needed. Multiple methods should be collectively considered to ensure that the final emissions are below the limiting values. To face these issues, waste heat recovery systems are employed. Exhaust gases can be processed, adsorbed, decomposed, and/or collected as nontoxic by-products to increase the quantity and improve the quality of steam recovery, reaching high fuel savings. Among all the technologies, the largely used methods are denitrification equipment, desulfurization equipment, and activated coke packed bed adsorption. EOS takes advantage of the fact that only a part of the oxygen in the air is consumed for coke combustion. Optimized exhaust recirculation in the sinter bed allows for the improvement of energy efficiency and emissions control. Charcoal and biomass utilization find optimal results in the emissions abatement. Optimization of raw material quality and processing conditions contribute to the overall efficiency of the process.