Alexander Babich

Effect of coke reactivity and nut coke on blast furnace operation

Abstract Two measures for coke saving and increase in blast furnace efficiency related to coke characteristics – reactivity and size – are discussed in this paper. Modern blast furnace operation with low coke rate and high injection rate causes a change in coke quality requirements. A discussion has arisen recently about highly reactive coke. Here, a theoretical analysis of influence of coke reactivity on the thermal reserve zone, direct reduction and carbon consumption in the blast furnace has been undertaken. Experiments have been performed using non-standard test scenarios that simulate coke behaviour under real blast furnace operating conditions. Coke reactivity and microstructure have also been investigated under the impact of alkali and pulverised coal ash and char. Operation of many blast furnaces has proved the possibility of coke saving and increase in productivity when using small-sized coke (so-called nut coke) mixed with the burden, but the reasons for this phenomenon, and consequently the limit for nut coke consumption, are still not very clear. An analytical method and cold model simulations have been used to quantify the change in shaft permeability and furnace productivity when using nut coke.

Influence of nut coke on iron ore sinter reducibility under simulated blast furnace conditions

Abstract One of the most important factors to increase the economic efficiency of the blast furnace process is to reduced coke losses (undersieve product known as nut coke). In recent years there has been increased interest in mixing nut coke in the sinter layers. In order to clarify the influence of nut coke on sinter reducibility, sinter and sinter–nut coke mixtures were isothermally reduced with 30%CO–70%N2 at 1173–1523 K using a muffle furnace supported by an on-line gas analyser. Reflected light microscopy, scanning electron microscopy and X-ray technique were used to characterise the microstructure and the different phases developed in the original and reduced sinter. Sinter reduced without nut coke participation exhibited reduction retardation at elevated temperatures (>1373 K) while the presence of nut coke prevented such phenomena. The rate controlling mechanism of sinter and sinter–nut coke mixture was predicted from the correlation between apparent activation energy calculations, mathematical modelling derived from gas–solid reaction model and microstructure examination.

Iron ores, fluxes and tuyere injected coals used in the blast furnace

Abstract Iron ores, fluxes and tuyere injected coals used as burden materials in the blast furnace have been characterised by chemical and granulometric analysis, moisture, density and porosity, softening and melting temperatures, reductibility, X-ray diffraction, electronic microscopy and thermoanalysis. Theoretical calculations on the influence of both the chemical composition and ash content of coals on some aspects of the blast furnace operation have been carried out. The combustion behaviour of pulverised coals in a pilot plant equipped with a combustion chamber has been studied to indicate what the behaviour of each type of coal will be, when injected in blast furnace tuyeres.

Conversion of injected waste plastics in blast furnace

Operation of several blast furnaces proved that waste plastic (WP) injection makes recycling of industrial and municipal organic wastes and coke saving possible. However, the extent and reaction kinetics of plastic conversion are hardly explored yet. Therefore, a comprehensive study on WP characteristics and conversion behaviour under simulated raceway, birds nest and shaft conditions, as well as on its interaction with coke, has been undertaken. Numerous analytical, laboratory and pilot facilities have been used. It has shown that despite favourable chemistry, it is hardly possible to reach a high conversion degree of plastics under the raceway conditions. Consumption of unburned residues in coke bed and in shaft is possible. The effect of this phenomenon on coke reactivity has to be considered as well.

3D-representation of phase and property diagrams in multi-component systems

Abstract This paper shows the potential of three-dimensional diagrams, using up-to-date computer graphics techniques. In contrast to the past perspective diagrams can now be generated from quantitative calculations of phase equilibria for systems with any number of components. These diagrams can even be made quantitatively readable. Furthermore new visualisation techniques from the field of virtual reality are used to make the complex data easier to understand.

Caracterización de carbones para la inyección por toberas en el horno alto

The efficiency of blast furnace operation with pulverized coal injection (PCI) by tuyeres is determined by the composition and properties of the used coals and by the quality of the ferrous burden and coke. A study in thermobalance of coals to be injected by tuyeres is carried out, and the softening and melting temperatures of coals ash are determined. The coal performance and its influence in the blast furnace operation is estimated.