Modeling and Simulation of Heat Front Propagation in the Iron Ore Sintering Process

Abstract

The aim of this work was to develop a model for the iron ore sintering process with special focus on heat front propagation through the packed bed and to provide a powerful tool ("SinterSim v1.1") for the simulation of the sintering process. Special interests were paid to the sub-models of fluid flow through the packed bed, oxidation of carbon monoxide, coke combustion, melting and solidifying of the bed material and the thermal decomposition the of ore components. Base case calculations were done showing very good agreement compared to values gained in test runs of the sintering process in a sinter pot. Numerous calculations with varied parameters were carried out to evaluate the behavior of the sintering process in means of a sensitivity coefficient for the specific variation. For duration of the sintering process and height of the sintering zone the most sensitive parameters turned out to be the mean diameter of the sinter mix material, void fraction inside the packed bed, the amount of coke breeze in the bed, the humidity of the green sinter mix and the amount of Fe 2 O 3 in the ore.

Three dimensional mathematical model of the iron ore sintering process based on multiphase theory

“…The raw materials used in the iron ore sintering process are furnished by several sources, from iron ore(mining sinter feed) to dust recycling within the steelworks and addition of slag agents for blast furnace and selected materials to enhance the sinter product quality, namely reactivity and mechanical strength, which plays crucial role on the blast furnace performance and reducing agent and energy consumption in the subsequent processes for steel production. In the sintering machine operation, the combustion of the solid fuels(coke breeze or anthracite) begins at the top of the layers, and as it moves, a relative narrow band of ignition zone moves downward through the bed, that can be strongly affected by the quality of the raw materials [4][5][6][7][8][9] . Several chemical reactions and phase transformations are affected, not only due to the heat front changes, but also due to modifications of local gas composition and initial melting temperatures of the mixture of raw materials.…”

“…At the present days, the reduction of CO 2 emissions has become an urgent issue in the steel industry as countermeasure for greenhouse emissions 3 . It is estimated that nearly 60% of the steel industry emissions are attributed to the pig iron production operation units, which includes sintering and blast furnace processes, and only the sintering process represents around 20% of this amount 1,5 . Therefore, sintering and blast furnace processes offer good opportunities to decrease the CO 2 emissions since mall decreasing of the coke breeze consumption and bonding agent used in iron ore sintering process could decisively contribute to decrease the environmental load of the steelmaking industry.…”

“…Thus, the main features of the model can be summarized as follows: a) dynamic interaction of the gas mixture with the solids; b) overall heat transfer of all phases which accounts for convection and radiation phenomena; c) kinetics of vaporization and condensation of water; d) decomposition of carbonates; e) reduction and oxidation of the iron bearing materials; f) coke combustion and gasification; g) volatile matter evolution; h) shrinkage of the packed bed; h) partial melt and re-solidification of the solids and i) phase changes to form alumina-calciumsilicates. This model differs significantly from the former ones due to the concept of multiple and coupled phenomena treatment, three -dimensional treatment of the sinter strand and detailed mechanism of chemical reactions involved in the process 1,2,4,5 . Therefore, this formulation represent an advance in the task of constructing a comprehensive mathematical model of the iron ore sinter process able to consider detailed phenomena that take place in the industrial operation.…”

Modeling Sintering Process of Iron Ore

“…However, there are few comprehensive mathematical models describing the sintering process in an industrial machine such as the usual Dwight-Lloyd process. Mitterlehner et al (Mitterlehner et al,2004), presented a 1-D mathematical model of the sinter strand focusing on the speed of the sintering front. Cumming and Thurnlby and Nath et al (Cumming &Thurnlby 1990 andNath et al, 1996), developed a 2-D mathematical model based on transport equations, however, their analysis considered a few chemical reactions and the rate of phase transformations were simplified.…”

Thermal Implications of Phase Transformations during Induration of Iron Ore Pellets Produced from Hematite

“…Examples of these product phases include calcium ferrites with some silica substitution, SFCA (silico-ferrite of calcium and aluminium) 11) in systems with over 1 % alumina, magnesioferrite (Mg x Fe 2ϩ 1Ϫx Fe 2 3+ O 4 ϪxϷ 0.3) in systems fluxed with dolomite or olivine, and iron substituted calcium silicate glasses (sometimes referred to as "slag"). Iron ore sintering models 12,13) assume some calcium ferrite formation and melting, but this treatment is limited to simple calcium ferrites. More complex phases found in industrial pellets have different thermodynamic properties (e.g.…”