The raceway in the ironmaking blast furnace is a void in front of the hot blast tuyeres where coke and supplementary fuel burn to supply heat to the ironmaking process. The air velocity through the tuyeres is high (around 200 m/s) and this causes the coke particles to circulate in a rotating flow field inside the raceway. The size and shape of the raceway determine the gas flow dstribution, the reactions that occur, and the temperature profiles in the lower part of the blast furnace. It is for these reasons that the raceway has been extensively researched in the past. . Literature review revealed that forming and breaking of the raceway has not been yet studied. So, in the present study, we have concentrated our effort to study the formation and breaking of the raceway for different blast and bed parameters. The experiments have been performed in two-dimensional glass models. An attempt has been made to develop a correlation for each case. The formation of the void has been studied with change in parameters like density and size of the particles, bed height. The theory of the void formation has been derived from the fundamental principles. The formation of raceway, has been studied with the change in blast parameters like particle density and diameter, bed height and model width. It was found that when raceway is formed there is a sudden increment in pressure drop. The condition for breaking of the raceway, has been studied with change in blast and bed parameters like particle size and density, bed height and model width. It was observed that during the breaking of raceway, pressure decreases continuously. New semi-empirical correlations have been developed using dimensional analysis for formation of void, formation of raceway, and breaking of the raceway. The raceway growth also characterized with change in model width, flow rate, particle diameter, density of the particles and bed height. A few experimental results have been compared with published data. New semi-empirical correlation have been developed using dimensional analysis for the growth of raceway. Velocity of the gas exiting from top of the bed has been measured with the help of hot wire anemometer. It was observed that the velocity leaving from the bed is more on top of the raceway compared to the velocity leaving from the other parts of the bed. High velocity was observed near the wall of the model. Coefficient of wall-friction and angle of internal friction in presence and absence of gas were studied to explain the effect of bed height on formation of the void and raceway. It was observed that in presence of gas, coefficient of friction between the particles and wall and angle of internal friction between particles decreased, compared to the values in absence of gas. To study the effect of mixed particles, on the formation and breaking of the raceway, different sized particles in fixed proportion were taken. It was found that the experiments were more reproducible in case of uniform sized particles compared to mixed particles. It was also observed that for the same average particle diameter, mixture particles requires more velocity to form the void and raceway. New semi-empirical correlations have been developed using dimensional analysis for the formation of void, formation of raceway, growth of the raceway, and breaking of the raceway. Finally, an attempt has been made to quantify the various forces (pressure, bed weight & frictional forces) present in the raceway. Results show that further investigation is required in quantifying these forces properly.

Thesis (M.S. in civil engineering)--Washington State University, August 2008. / Includes bibliographical references (p. 79-80).

Thesis (Ph.D.)--University of Wollongong, 2009. / Typescript. Includes bibliographical references: leaf 248-256.

Thesis (M.S.)--Massachusetts Institute of Technology, 2002. / Includes bibliographical references (p. 51.52). Also available online.

Thesis (Mechanical Engineer and M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2003. / Thesis advisor(s): Young S. Shin. Includes bibliographical references (p. 161-162). Also available online.

Seven iron ore pellets, two sinters, and one lump ore were studied in CO-CO₂-H₂-N₂ atmospheres from 350°C to 750°C, simulating the upper stack of the ironmaking blast furnace. Experiments were performed in a flowing gas reactor on single specimens of each type of substrate. Two different measurements were made: (1) the carbon deposition and concurrent iron oxide reduction rate at 550°C in 30%CO, 10%CO₂, 2%H₂, and 58%N₂; and (2) the amount of carbon deposited during a programmed increase in temperature and change in CO-CO₂ ratio simulating the descent of an ore specimen in the blast furnace stack. The rates of the concurrent reaction were determined from mass balances based on gas chromatographic analyses of the CO, CO₂H₂, and N₂ in both the inlet and outlet gases and the continuously recorded mass of the specimen. The materials were examined as to chemical composition, internal structure, porosity, and surface area. Elemental analyses of single iron oxide grains were made by electron microprobe. Slag materials and composition, and crystallinity were determined by microprobe and X-ray diffraction. The results of the experiments show that carbon deposition occurs only in the presence of metallic iron which is produced from the concurrent reduction of Fe₃O₄. The degree of reduction is controlled largely by the structure of the substrate, but the carbon deposition is controlled only by the chemical composition of the substrate--specifically, silicon in the iron and the CaO to MgO ratio. In the blast furnace simulation, the carbon deposition increases for pellets fluxed with dolomite to a maximum with lime-fluxed pellets. The effects of H₂ and CO₂ on the reactions were investigated in the isothermal experiments using an Empire pellet. The CO₂ controlled only the reduction, and this by diffusion of the CO₂. The hydrogen in very small amounts enhanced the deposition of carbon, probably by eliminating the presence of the inactive iron carbides. Under blast furnace conditions, the changes in the operation when the chemistry of the ore feed is changed to fluxed pellets will be due more to the shifts in the available heat within the stack from carbon deposition than to the low temperature reduction of the ores, which does not change with the addition of the flux materials.

The aims of the thesis were to study the response of temporary soil-filled walls both experimentally and numerically, and to develop an efficient and accurate analytical model to predict 2-D planar response from blast loading which could be used to efficiently calculate a pressure-impulse (P-I) curve. An explicit finite element (FE) formulation was constructed using LS-Dyna software, and two analytical models were also derived and presented: a Rigid-Body Rotation model as a preliminary model, and the Rigid-Body Hybrid model as the proposed model of this thesis. Seven full-scale experiments which consisted of blast loading simple free-standing soil-filled Hesco Bastion (HB) walls are presented. Apart from comparison of an experimental result where the soil-fill in the wall possessed sizable cohesion, the response of the Rigid-Body Hybrid model was in very good agreement with the experiments overall (within 10 %). A soil sensitivity study was conducted and overall very good agreement was reached between the Rigid-Body Hybrid model in comparison with the FE model in its ability to capture differences in displacement-time histories from differences in soil parameters. Comparison with the FE model for different height-to-width ratios of walls showed that the Rigid-Body Hybrid model was within 10 % for all rotation angles and predictions of critical overturning impulse for height-to-width ratios of walls . P-I curves were developed using the analytical and FE models for the three different wall configurations studied in the experiments. The results demonstrated that the proposed Rigid-Body Hybrid model is useful for calculating a P-I curve for a HB wall efficiently and yielded very accurate results (within 5 % for the impulse asymptotes).

The aims of the thesis were to study the response of temporary soil-filled walls both experimentally and numerically, and to develop an efficient and accurate analytical model to predict 2-D planar response from blast loading which could be used to efficiently calculate a pressure-impulse (P-I) curve. An explicit finite element (FE) formulation was constructed using LS-Dyna software, and two analytical models were also derived and presented: a Rigid-Body Rotation model as a preliminary model, and the Rigid-Body Hybrid model as the proposed model of this thesis. Seven full-scale experiments which consisted of blast loading simple free-standing soil-filled Hesco Bastion (HB) walls are presented. Apart from comparison of an experimental result where the soil-fill in the wall possessed sizable cohesion, the response of the Rigid-Body Hybrid model was in very good agreement with the experiments overall (within 10 %). A soil sensitivity study was conducted and overall very good agreement was reached between the Rigid-Body Hybrid model in comparison with the FE model in its ability to capture differences in displacement-time histories from differences in soil parameters. Comparison with the FE model for different height-to-width ratios of walls showed that the Rigid-Body Hybrid model was within 10 % for all rotation angles and predictions of critical overturning impulse for height-to-width ratios of walls . P-I curves were developed using the analytical and FE models for the three different wall configurations studied in the experiments. The results demonstrated that the proposed Rigid-Body Hybrid model is useful for calculating a P-I curve for a HB wall efficiently and yielded very accurate results (within 5 % for the impulse asymptotes).

The PCI technology is well established for reducing the consumption of economic and environmentally expensive coke in blast furnace iron-making. Often, coal blends show unexpected combustion performance which cannot be explained on the basis of individual coal properties particularly coal rank and volatile matter. Several coals were combusted in this study under controlled conditions in a drop tube furnace. Fixed bed reactor, XRD, SEM and BET analyses were used to understand the mechanism of combustion of coal blends. Burnout of the coal blends did not change linearly with volatile matter of blends. The study demonstrated that combustion behaviour of coal blends was influenced by several properties of individual coals and cannot be estimated by using any single coal parameter. Carbon structure of coal as well as the interaction of volatile matter of individual coals was found to have a strong influence on the burnout of coal blends. Pet-cokes were generally found to burn with a greater difficulty. Carbon structure of pet-cokes was found to have a significant effect on the burnout such that coal blends with highly ordered pet-coke indicated lower burnout. The study shows that up to 10% of pet coke did not change the burnout of PCI blends significantly. As far as combustion is concerned, the drop tube furnace test provides a reasonable distinction of the effect of coal properties for PCI application.

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