Dissertations / Theses on the topic 'Metallurgical coke'

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1

Moreland, Angela. "The structure and strength of metallurgical coke." Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/13759.

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This study aimed to investigate the relationship between the tensile strength of metallurgical coke and both the textural composition of the carbon matrix and the porous structure of the coke, and further to assess the use of these structural features as bases of methods of coke strength prediction. The forty-four cokes examined were produced in a small pilot-oven from blended-coal charges based on six coals differing widely in rank. Their textural composition was assessed by incident polarized-light microscopy while pore structural parameters were measured by computerized image analysis allied to reflected light microscopy. The tensile strength of coke could be related to textural data with accuracy using several relationships, some of which were based on a model for the tensile failure of coke. Relationships between tensile strength and pore sturctural parameters were less successful, possibly because of difficulties associated with the measuring system used. Neverthless relationships involving combinations of pore structural and textural data were developed and investigated. It was shown that relationships between tensile strength and calculated textural data had promise as the basis of a method of coke strength prediction. Also, tensile strengths could be calculated from the blend composition and the tensile strength of the coke produced from component cokes. Both methods have value in different situations.
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2

Walker, Alan. "The carbon texture of metallurgical coke and its bearing on coke quality prediction." Thesis, Loughborough University, 1988. https://dspace.lboro.ac.uk/2134/10950.

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The carbon in metallurgical coke is composed of textural units, varying in size and shape depending on the rank of coal carbonized. These induce a characteristic texture to coke surfaces. This thesis describes a study of the bearing of this texture on coke strength, particular emphasis being placed on investigating the feasibility of using textural composition data, determined by either scanning electron microscopy (SEX) of etched surfaces or polarized-light microscopy (PLX) of polished coke surfaces, as a basis of predicting the tensile strength of cokes produced from blended-coal charges from the behaviour of individual blend components. Scanning electron microscopy (SEM) of fractured coke surfaces revealed differences in the mode of fracture of textural components which implied variations in their contribution to coke strength. The tensile strengths of pilot-oven cokes, produced from blended-coal charges, could be related to their measured PLM textural compositions using equations derived from consideration of simple models of intergranular and transgranular fracture. The coke strengths could also be related, with greater precision, with textural data calculated from the coal blend composition and either the SEM or the PLM textural data for the cokes from the individual blend components. It was further found that the strength of blended-coal cokes were additively related to the blend composition and the tensile strengths of the single-coal cokes. Such relationships are useful, at the very least, for predicting the strength of cokes from other blends of the same coals carbonized under similar conditions. The various approaches to coke strength prediction have potential value in different situations.
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3

Sato, Hiroshi. "Strength of metallurgical coke in relation to fissure formation." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/8350.

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The size distribution and strength of metallurgical coke are factors vital for the steady and high-efficiency operation of a blast furnace, since these factors govern stack penneability. Coke strength influences the size of lump coke not only because of size degradation by impact and abrasion during transfer to and descent in the blast furnace, but also because of its influence on the fracture which takes place in the coke layer during carbonisation and the effect this has on the initial mean size and size distribution of the feed coke. Therefore, the elucidation of the relationship between coke strength and the fissure fonnation phenomena is significant. In this study, therefore, the coke strength development during carbonisation has been examined in conjunction with various parameters, such as the degree of carbonisation of the coal, namely the extent or fraction of pyrolytic reaction, and the degree of graphitisation of the coke, as well as carbonisation temperature and heating regime. The porous structure of coke has also been examined with a view to establishing a relation between the porous structure and the coking properties of the coal carbonised. The quality of coke porous structure was evaluated by parameters introduced in this study, i.e., the pore size distribution and pore rugosity factors. A poor porous structure is shown to be associated with high proportion of small pores and pores with a rough surface. These features are considered to stem from poor coking properties and the consequent poor adhesion between coal particles. An attempt has also been made to establish a mathematical model capable of predicting the degree of fissuring of coke during carbonisation by utilising the understandings obtained in this study of the coke strength development during carbonisation and the effect of coal properties on coke strength. Coke samples large enough to facilitate the observation of the degree of fissuring in relation to various coal properties and heating conditions, were made to evaluate the mathematical model and introduce the concept. The concept that fissuring takes place when developing thennal stress exceeds the developing coke strength is demonstrated to be capable to evaluate the effects of coal properties and heating conditions on the degree of fissuring observed.
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4

Ismail, Mohamed. "An investigation into the use of petroleum coke as a substitute for metallurgical coke." Thesis, University of Nottingham, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.663253.

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Metallurgical coke is used primarily as a reducing agent for the reduction of iron in the blast furnace. Due to the high cost, high demand and reduced availability of high quality coking coals used in the production of metallurgical coke, alternative resources are being sought. One possible alternative is to use petroleum coke. Petroleum coke has the advantage of having a higher calorific value than traditional coke, at relatively low cost with a low ash content and ready availability. However the drawback to petroleum coke relates to its poor mechanical strength and reactivity. The main focus of this study was therefore to develop a process for producing petroleum coke with the required qualities for blast furnace application. In an initial series of experiments tests including proximate analysis, ultimate analysis, intrinsic reactivity test, DSC, direct tensile strength, calorific value, X-ray computed tomography, X-ray diffraction and scanning electron microscopy were used to characterise a wide range of petroleum coke and compare it with metallurgical coke properties. X-ray computed tomography methodology was also used to provide 3D information on coke lumps. Results show that none of the petroleum coke samples met the full requirements needed for use as a good blast furnace coke.
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5

GIGLIO, ANDRE MALICIA. "QUALITY PREVISION MODEL OF METALLURGICAL COKE TO BE USED ON BLAST FURNACES USING A COKE TEST FACILITY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=29703@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
É bem conhecido o alto peso que o coque representa no custo final do ferro-gusa, além do que, as suas propriedades estão intimamente ligadas à performance dos altos-fornos. Portanto, buscar uma qualidade do coque compatível com as necessidades do alto-forno e com o menor custo possível, se transforma em uma tarefa difícil senão se dispuser de ferramentas que permitam uma correta seleção de carvões e testes prévios em fornos pilotos. Dentre as propriedades utilizadas pelos altofornistas para qualificar o coque, se destacam a CSR - resistência mecânica após reação com CO2, e a CRI - índice de reatividade, por serem, respectivamente, uma medida direta da reação de Boudouard - solution loss, e da associação desta com a resistência do coque. Com isso se torna possível prever o consumo desta matéria prima nos altos fornos e, devido a sua grande influência nos custos da operação, mensurar seu impacto na economicidade do processo. A unidade de coqueificação do processo heat recovery da ThyssenKrupp Companhia Siderúrgica do Atlântico - TKCSA, possuindo uma concepção diferente do tradicional by product coking process, utiliza um forno piloto próprio, especificamente projetado pela empresa, com o qual se procura simular as condições operacionais das unidades de coqueificação. Entretanto, essa unidade de coqueificação ainda carecia de um estudo experimental especifico capaz de permitir uma análise comparativa confiável entre o coque produzido e o das baterias industriais. O objetivo principal desta dissertação foi desenvolver um modelo de previsão da CSR -resistência mecânica do coque após reação com CO2, e do CRI através da coqueificação de misturas de carvões, obtidas por diferentes metodologias, em no forno escala piloto e sua comparação estatística com os dados obtidos em escala industrial na ThyssenKrupp Companhia Siderúrgica do Atlântico - TKCSA. O modelo de previsão para o CSR quando obtido através de escala piloto se mostrou bastante aderente aos dados obtidos em escala industrial. Portanto, os procedimentos utilizados e este modelo desenvolvido mostraram-se adequados, e podendo assim ser usados como ferramenta para auxiliar na seleção e compra de carvões.
It is well known that coke has a major importance on the final cost of the Hot Metal and besides this fact its properties are closely connected with the performance of blast furnaces. Therefore, seeking a type of coke compatible with the blast furnace technical requirements and at the lowest possible price may become a hard challenge if neither a prediction tool is available to accomplish a correct selection of coals nor previous test were made on coke test facility. Among the properties used by the Blast Furnace specialists to qualify the coke, it can be highlighted CRI - Coke Reaction Index and CSR - Coke Strength after Reaction with CO2, because they represent a direct measure of the Boudouard reaction – solution loss, and its association with the coke strength, respectively. Based on them it is possible to predict the consumption of this raw material in the Blast Furnaces and, due to its high influence on the operational costs, measure its impact on the overall process economy. The Coke Plant unit at thyssenkrupp Companhia Siderurgica do Atlantico - TKCSA follows the coking process known as heat recovery and its concepts differ from the traditional one, by product. This unit uses its own coke test facility, specifically designed by the company s experts to simulate the operational conditions at the coke plant industrial furnaces. However, the coke test facility still required further specific experimental study capable of making a reliable comparison analysis between the cokes produced in it with the one from the industrial coke batteries. The main goal of this dissertation is to develop model to predict the CRI - Coke Reaction Index and CSR - Coke Strength after Reaction with CO2, through the coking process of coal blends, generated by different methodologies, charged on the coke test facility statistically compared with the ones from the industrial Coke plant at thyssenkrupp Companhia Siderúrgica do Atlântico - TKCSA. The prediction of CSR represented when generated through the coke test facility showed good adherence with the values obtained with the industrial scale. Therefore, the current procedures used on the developed model has proved to be adequate and may be used as a predicting tool to help the purchase of coals.
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6

Daw, E. R. "A study of some structural features relevant to the degradation of metallurgical coke." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/12641.

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Metallurgical coke for blast furnace and foundry use, and for some domestic boiler cokes are produced by carbonising coals in slot-type ovens. The coal is heated by heat transferred from the hot oven walls (usually 1250°C) so that a temperature gradient is set up within the oven charge. A layer of plastic coal is formed (350-500°C) which moves progressively towards the oven centre as carbonisation proceeds. Immediately after re-solidification, and again near 700°C, the semi-coke suffers shrinkage as the carbon structure reorganises The post re-solidification shrinkage is the more severe and results in large, horizontal and vertical primary fissures being formed which allow breakage of the charge into lumps as it is pushed from the oven. A large central fissure, formed when the two plastic layers meet, divides the charge into two. Further breakage occurs at primary fissures on handling the coke after pushing. Smaller secondary fissures present in the resultant coke lump are believed to be a result of the shrinkage near 700°C. Coke has three roles in the blast furnace: as a source of heat, a source of reducing agents and as a support for the burden. The latter function is particularly important at the bottom of the stack when coke is the only solid material present. The blast furnace output is dependent on the quantity of air that can be pushed up the stack. This depends on the permeability of the coke bed in the lower reaches of the stack. To maintain permeability, the coke should not suffer size degradation as it progresses down the stack; a mixture of large and small coke particles is disastrous. Thus coke quality tends to be assessed in terms of resistance to size degradation in a drum test. Size degradation occurs as a result of volumetric breakage at fissures and abrasion of surfaces. Brittle fracture theory suggests that volumetric breakage should occur as a result of the propagation of secondary fissures in coke lumps.
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7

Ahmad, Yousef. "Oxidation of Graphite and Metallurgical Coke : A Numerical Study with an Experimental Approach." Thesis, KTH, Materialvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-193604.

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At the royal institute of technology (KTH) in the department of applied process metallurgy, a novel modelling approach has been developed which allows a dynamic coupling between the commercial thermodynamic software Thermo-Calc and the commercial computational fluid dynamic (CFD) software Ansys Fluent, only referred to as Fluent in the study. The dynamic coupling approach is used to provide numerical CFD-models with thermodynamic data for the thermo-physical properties and for the fluid-fluid chemical reactions occurring in metallurgical processes. The main assumption forthe dynamic coupling approach is the existence of local equilibrium in each computational cell. By assuming local equilibrium in each computational cell it is possible to use thermodynamic data from thermodynamic databases instead of kinetic data to numerically simulate chemical reactions. The dynamic coupling approach has been used by previous studies to numerically simulate chemical reactions in metallurgical processes with good results. In order to validate the dynamic coupling approach further, experimental data is required regarding surface reactions. In this study, a graphiteand metallurgical coke oxidation experimental setup was suggested in order to provide the needed experimental data. With the experimental data, the ability of the dynamic couplings approach to numerically predict the outcome of surface reactions can be tested.By reviewing the literature, the main experimental apparatus suggested for the oxidationexperiments was a thermo-gravimetric analyzer (TGA). The TGA can provide experimental data regarding the reaction rate, kinetic parameters and mass loss as a function of both temperature and time. An experimental setup and procedure were also suggested.In order to test the ability of Fluent to numerically predict the outcome of surface reactions, without any implementation of thermodynamic data from Thermo-Calc, a benchmarking has been conducted. Fluent is benchmarked against graphite oxidation experiments conducted by Kim and No from the Korean advanced institute of science and technology (KAIST). The experimental graphite oxidation rates were compared with the numerically calculated graphite oxidation rates obtained from Fluent. A good match between the experimental graphite oxidation rates and the numerically calculated graphite oxidation rates were obtained. A parameter study was also conducted in order to study the effect of mass diffusion, gas flow rate and the kinetic parameters on the numerically calculated graphite oxidation rate. The results of the parameter study were partially supported by previous graphite oxidation studies. Thus, Fluent proved to be a sufficient numerical tool for numerically predicting the outcome of surface reactions regarding graphite oxidation at zero burn-off degree.
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8

Chapman, Michael Wallace. "Insoluble oxide product formation and its effect on coke dissolution in liquid iron." School of Mechanical, Materials and Mechatronic Engineering - Faculty of Engineering, 2009. http://ro.uow.edu.au/theses/3039.

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A significant body of work exists around coke dissolution into liquid iron, however there are key aspects of this important reaction that are not well described. This study was focused on gaining the answers to the questions “How does the coke mineral matter behave during coke dissolution?” and “Can the effects of sulphur and oxide layer formation on the dissolution rate be separated and quantified?”. Issues that must be addressed if the understanding of the kinetics of this reaction is to be advanced and coke's use in the blast furnace further optimised.To this end, a detailed investigation was conducted examining the influence of coke mineral matter on coke (carbon) dissolution into liquid iron. This project was focused on the mineral matter layer that forms at the coke/iron interface and how the presence of this layer affects the kinetics of carbon dissolution from the coke into the liquid iron. A range of experimental techniques were used to identify and characterise the mineral layer as it formed at the coke/iron interface and to assess the layers influence on the carbon dissolution kinetics.Carbon dissolution experiments, utilising a carburiser cover technique, were carried out where carbon and sulphur transfer to an iron-carbon melt was measured over time at temperatures of 1450°C, 1500°C and 1550°C. This technique allowed fundamental data on the dissolution rate constant to be calculated, and the effects of temperature, melt sulphur and different carbonaceous materials to be explored.Development of the mineral layer at the coke/iron interface as a function of both time and temperature was studied utilising a quenched carbon dissolution technique that was developed during the project. This technique had the additional benefit of allowing the composition of the melt to be determined for a larger range of elements than the dissolution experiments. The quenched carbon dissolution experiments complemented the carbon dissolution experiments and allowed direct comparisons between the dissolution behaviour measured in the dissolution experiments and the composition and morphology of the mineral layer observed in the quenched samples.The dissolution studies were further complemented by sessile drop measurements of the wetting behaviour of iron on the mineral phases that were identified in the mineral layer present at the coke/iron interface, thermodynamic modelling utilising the MTDATA software package and a conceptual model of the interfacial mineral layer.A mineral layer was observed to have formed at the coke/iron interface during coke dissolution into liquid iron at experimental temperatures ranging from 1450°C to 1550°C. The mineral layer was solid at these temperatures and persistent at the interface. The amount of mineral matter present in the mineral layer was observed to be increasing with increased reaction time. The composition and structure of the mineral layer changed with both experimental time and temperature. The composition of the mineral layer was principally composed of oxides of aluminium and calcium, present as various calcium aluminates and calcium sulphides. Initially the mineral layer was a loose agglomeration of particles of which a majority were alumina particles. As the dissolution reaction proceeded, the loose agglomeration of particles was replaced by an open acicular layer that was predominantly the calcium aluminate CaO.6Al2O3 (CA6). As the dissolution reaction continued further, the calcium aluminates became increasingly richer in calcium oxide, with the predominate phase present in the mineral layer progressing through the calcium aluminates phases CA6 to CaO.2Al2O3 (CA2) and onto CaO.Al2O3 (CA). The apparent calcium enrichment of the mineral layer was observed to occur more rapidly as the experimental temperature increased. Accompanying the compositional changes in the mineral layer, the morphology of the mineral layer was also observed to change. The mineral layer was formed as an initial loose agglomeration of alumina particles, changing to an open acicular structure consisting of CA6/CA2 before being converted to a dense layer as the dissolution reaction proceeded and the composition of the mineral layer changed to CA and calcium sulphide (CaS) appeared at the interface.It was found that the formation of the calcium sulphide layer was preceded by the formation of the calcium aluminate layer. Only after the calcium aluminate layer had experienced progressive calcium enrichment and the CA and CA2 phases had formed did the CaS phase appear at the iron interface. Thermodynamic analysis of the experimental results confirmed that the formation of the calcium enriched calcium aluminates, CA2 and CA, were a necessary requirement to stabilise the calcium sulphide layer for the coke composition studied.The kinetics of carbon dissolution from the coke to the liquid iron were observed to be dependent on the structure of the interfacial mineral layer. This dependence was manifest as two stage behaviour in the first order mass transfer plots. The initial stage, characterised by rapid carbon dissolution, was observed while the mineral layer was developing or had the open acicular structure of the CA6/CA2 layer. The second stage was characterised by a significant reduction in the rate of carbon dissolution. The onset of the second stage was coincident with the change in the composition of the mineral layer from CA6/CA2 to CA2/CA and the associated densification of the mineral layer. In stating that the nature of the mineral layer affects the dissolution kinetics, a change in the reaction control mechanism is implied. This represents a change in the coke dissolution kinetics from simple mass transfer control to a mixed control regime where both mass transfer and the mineral (product) layer are active.In an attempt to overcome the problems associated with the heterogeneity of coke a coke analogue was developed. In the coke analogue the composition and dispersion of the carbonaceous and mineral matter (oxides) are controlled and the porosity is fixed. When single phase calcium aluminates were introduced into the coke analogues, calcium enrichment of the resulting calcium aluminate mineral layer was observed. The observed carbon dissolution kinetics were dependant on the structure of the interfacial calcium aluminate layer. Consistent with the coke dissolution studies, the calcium aluminate layer formed at the coke analogue iron interface during carbon dissolution was at least in part rate controlling the carbon dissolution reaction for the coke analogues studied.Utilising the sessile drop experimental technique the wettability with liquid ironcarbon-sulphur alloys of the predominate phases that were observed in the mineral layer were measured. It was observed that the contact angle decreased as the proportion of lime (CaO) in the calcium aluminate increased. Further it was observed that while the presence of sulphur in the melt increased the contact angle for the alumina and CA6 substrates, on the CA2 and CA substrates the contact angle was decreased. The improvement in the wetting of the CA2 and CA substrates with sulphur was attributed to the formation of CaS at the substrate/droplet interface.This study has produced new fundamental data on the growth and development of the mineral layer and the wettability of the predominate calcium aluminates observed in the mineral layer. These detailed studies have illuminated the changing nature of the layer in terms of both composition and morphology and found that the kinetics of carbon dissolution from the coke to the liquid iron were dependant on the structure of the interfacial mineral layer.
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9

Goncalves, e. Oliveira Fernando Lucas. "Étude des Matériaux carbonés utilisés comme réducteurs pour la production des alliages de manganèse dans le four électrique." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2010. http://www.theses.fr/2010ECAP0008/document.

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Notre travail est consacré à l’étude des matériaux carbonés utilisés comme réducteurs pour la production des alliages de manganèse dans le four électrique à arc immergé. Le choix du réducteur est important pour l’optimisation du procédé métallurgique et sa réactivité au CO2 est le paramètre le plus important utilisé par les producteurs de ferroalliages pour évaluer sa qualité. Les objectifs de notre travail sont : ? d’établir les critères de sélection du coke métallurgique ou réducteur de remplacement, utilisés pour la production des alliages de manganèse dans le four électrique, en utilisant la réactivité au CO2 comme le principal paramètre pour évaluer sa qualité ; ? d’un point de vue plus fondamental, apporter une meilleure compréhension des réactions du carbone dans le réacteur industriel. Dans l’optique d’une modélisation globale du four électrique, notre travail fournit des paramètres cinétiques d’une des réactions les plus importantes du procédé : la réaction de Boudouard. L’étude de la réductibilité des oxydes de manganèse pourrait donc être une nouvelle étape vers la construction d’un modèle global du réacteur industriel. Un troisième volet d’expériences utile à la modélisation serait l’étude de l’influence de la nature et du calibre du réducteur sur la résistivité électrique de la charge
The main aims of our work have been to establish criteria useful for reductant selection, using coke reactivity to CO2 as the main parameter for reductant quality assessment and, from a fundamental point of view, to develop a better understanding of carbon reactions inside the industrial reactor. Therefore, Boudouard reaction has been studied on three increasing scales: intrinsic chemical reaction, coke lump, and coke bed scales. Several different types of carbonaceous materials have been studied. They represent the variety of reductants commonly used in the production of manganese ferroalloys in the electric furnace. It has been shown that this extended range of reductants introduces large differences between their characteristics, mainly between their reactivity to CO2. Regarding the coke lump gasification kinetics, the Langmuir-Hinshelwood model has been used to represent the intrinsic rate of the Boudouard reaction. A good correlation has been found between the initial gasification rates of the coke beds and the single coke lumps. The difference between these rates increases with increasing reductant reactivity. It is possible to determine coke gasification regime inside the industrial electric arc furnace using single particle and coke bed gasification models. The overall rate at which coke reacts with CO2 inside the industrial reactor is probably limited by the intrinsic chemical reaction. Therefore, a reactivity index, based on the initial gasification rate of the reductant, measured in the chemical-kinetics controlled regime, seems to be adapted to the reductant quality assessment. An additional technique could be the microtextural analysis
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10

Han, Bing. "Studies of metallurgical coke behaviour and properties under conditions relevant to the bosh and deadman regions of a blast furnace." Thesis, Loughborough University, 1993. https://dspace.lboro.ac.uk/2134/28134.

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The primary aim of this study was to examine changes in coke properties in an attempt to establish a better understanding of the behaviour and degradation mechanism of metallurgical coke in the unfavourable mechanical, thermal and chemical environment of a blast furnace. The attainment of such knowledge would assist coke manufacturers and blast furnace operators to monitor and tailor the properties of the metallurgical coke to meet the optimum requirements necessary for efficient furnace operation.
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11

Dong, Shanning. "Development of analytical methods for characterizing metallurgical coke and the injectant coal chars, tars and soots formed during blast furnace operation." Thesis, Imperial College London, 2008. http://hdl.handle.net/10044/1/1329.

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Blast furnace operation with coal injection at rates greater than 200 kg coal/tonne of hot metal, a rate less than the theoretical limit, has been often found problematic. The present study aims to gain a better understanding of the fate of injectant coal in the blast furnace by means of characterizing samples extracted from working BFs and pilot-scale rigs. The NMP (1-methyl-2-pyrrolidinone) solvent has been used to extract carbons relevant to BF operation, and comparison of the Size Exclusion Chromatographic patterns of the extracts has indicated that injectant coal is not able to completely combust or even completely pyrolyze during its journey from the tuyere nose through to and out of the “raceway”, and that the secondary reactions e.g. dehydrogenation and repolymerization, of coal tars are closely associated with the formation of the “soot-like” material. This has been confirmed by combined results from analyses using Ultraviolet-fluorescence, FT-IR spectroscopy and Transmission Electron Microscope. In addition, an attempt has been made to use FT-Raman spectroscopy as a relatively rapid technique to characterize various NMP-extracted carbon samples, with the aim to differentiate between carbons from different regions of the blast furnace. Two Raman spectral ratios, i.e.ID/IG ( intensity ratio of D to G band) and IV/IG(intensity ratio of the valley between D and G band to G band), have been found to be suitable parameters to indicate the size of the graphitic crystallites and the overall homogeneity of the carbon structures, respectively. Raman spectroscopy has been found to be able to closely estimate the composition of synthetic carbon mixtures, to indicate the different time-temperature histories that carbons had experienced at tuyere level. Finally, the ID/IG vs. IV/IG mapping has demonstrated its great potential as a reliable method based on Raman spectroscopy to differentiate between various types of carbons.
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12

Orellana, Daniel Rigon. "Incorporação de moinha de carvão vegetal na produção de coques em forno piloto." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/158269.

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A reutilização de resíduos e sua destinação são desafios seguidamente enfrentados na indústria. Por ser extensa e empregar uma grande variedade de processos, matérias-primas e insumos, a cadeia do aço se beneficia por ter ampla flexibilidade e diversas possibilidades de reintrodução de compostos em sua rota de fabricação. Resíduos carbonosos, por exemplo, podem ser parcialmente usados em misturas de carvões no processo de coqueificação dependendo do tamanho e da composição química. Este trabalho, teve como objetivo, avaliar a influência da adição de moinha de carvão vegetal em uma mistura de carvões para a produção de coques em forno piloto de coqueificação e determinar os teores máximos de incorporação suportados pela mistura, avaliando parâmetros de qualidade do coque. Para isso, a moinha de carvão vegetal de eucalipto foi introduzida em duas frações granulométricas distintas, uma composta por partículas mais grosseiras (fração G) e outra composta por partículas mais finas (fração F), e caracterizado juntamente com a mistura utilizada. Posteriormente, os coques produzidos em forno piloto também foram caracterizados através de diversas análises: imediata, elementar, área superficial, porosidade, textura óptica, reatividade em termobalança, CRI/CSR e DI150/15. Os resultados atingidos mostraram que inserção da fração G de moinha comprometeu menos os parâmetros de qualidade dos coques com carvão vegetal. Teores de até 3% de moinha foram suportados para essa distribuição de tamanho de partícula enquanto que para a fração F, somente 1%. Outro fator observado foi que os coques produzidos com adição de moinha de carvão vegetal não tiveram queda significativa no teor de enxofre, a exceção da amostra contendo 10% de carvão vegetal na fração G. Em todas as amostras com moinha de carvão vegetal também foi possível notar o aumento da área superficial em relação ao coque de referência. Os testes termogravimétricos dinâmicos também trouxeram informações relevantes a respeito das temperaturas e taxas aparentes de reações dos coques feitos com moinha de carvão vegetal.
The reuse of waste materials and its destination are challenges continuously faced for industry. For being far-flung and apply a huge variety of process, raw materials and inputs, the steel supply chain benefits from having a high flexibility and many possibilities of reintroducing compounds in its manufacturing route. For example, carbonaceous materials can be used partially in coal blends for cokemaking process depending on particle size and chemical composition. The current work aimed to evaluate the influence of adding fine charcoal to a coal blend for coke production in a pilot oven and to determine the maximum content tolerated for the blend, assessing coke quality parameters. For this, a eucalyptus charcoal residue was introduced in two different size distributions, one composed of coarser particles (fraction G) and another of finer (fraction F), and characterized together with the coal blend used. Afterwards, the cokes produced in pilot oven were also characterized through several analyzes: proximate, ultimate, surface area, porosity, optical texture, reactivity on thermobalance, CRI/CSR e DI150/15. The results achieved showed that the insertion of charcoal on fraction G compromised less the quality parameters of cokes with charcoal. Contents up to 3% of charcoal were tolerated for this particle size distribution while for fraction F, only 1%. Another point noticed was that the coke produced with charcoal addition had no significant drop on sulfur content, with the exception of the coke sample with 10% of charcoal and fraction G. In all samples with charcoal it was also possible to see an increase on surface area in relation to the reference coke. The dynamic thermogravimetric tests also provided relevant information regarding to the temperatures and apparent reaction rates of cokes made with charcoal.
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13

Hanson, Svenja. "Interfaces between the textural components in metallurgical cokes." Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/28121.

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Abstract:
The work presented in this thesis aims at furthering the understanding of the microtexture of metallurgical cokes with regard to the interfacial properties of their optical components. Metallurgical coke, on the scale considered, can be understood as a composite of unfused carbon embedded in a porous matrix of fused material. The matrix is composed of textural units varying in size and shape depending on the rank of the coal or blend of coals carbonised. The quality of the interfaces between them and of those they form with the unfused material can reasonably be expected to influence macroscopic coke properties such as mechanical strength.
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14

Yu, Xin. "Thermodynamics and kinetics of gasification reactions of metallurgical cokes." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47320.

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15

Grigore, Mihaela Materials Science &amp Engineering Faculty of Science UNSW. "Factors influencing coke gasification with carbon dioxide." 2007. http://handle.unsw.edu.au/1959.4/40623.

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Abstract:
Of all coke properties the influence of the catalytic mineral matter on reactivity of metallurgical cokes is least understood. There is limited information about the form of minerals in the metallurgical cokes and no information about their relative concentration. A comprehensive study was undertaken for characterisation of mineral matter in coke (qualitative and quantitative), which enabled quantification of the effect of catalytic minerals on the reaction rate, and establishment of the effect of gasification on the mineral phases. Also, the relative importance of coke properties on the gasification reaction rate was determined. The reactivity experiments were performed at approximately 900??C using 100% CO2 under chemically controlled conditions. The mineralogical composition of the investigated cokes was found to vary greatly as did the levels of catalytic mineral phases. These were identified to be metallic iron, iron sulfides and iron oxides. The gasification reaction rate at the initial stages was strongly influenced by the content of catalytic mineral phases and also by the particle size of the catalytic mineral matter. The reaction rate increased as the contact surface between catalyst and carbon matrix increased. Catalytic mineral phases showed a strong influence on the reaction rate at early stages of reaction. But their influence diminished during gasification. At later stages of reaction the influence of micropore surface area became more important. The influence of the catalytic mineral phases diminished during gasification because the catalyst was inactivated to some degree and the contact surface between the catalyst and carbon matrix diminished due to the strong gasification of the carbon around the catalyst particles. The partial inactivation of the catalytic mineral phases occurred because metallic iron and pyrrhotite were oxidised by CO2 to iron oxide, and in turn iron oxide reacted with other mineral phases, which it is associated with, to form minerals that are not catalysts. It is noteworthy that a significant percentage of the mineral matter present in the investigated cokes was amorphous (44 - 75%). The iron, potassium and sodium present in the amorphous phase did not appear to catalyse gasification, but their potential contribution to gasification could not be completely excluded.
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16

Mkhatshwa, Sindile Francisca. "Assessment of the mineralogical variability of the A1, UE1A, and A5-reefs at Cooke Section, Rand Uranium, using MLA-based automated mineralogy." Thesis, 2012. http://hdl.handle.net/10210/6347.

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Abstract:
M.Sc.
This study focuses on the mineralogical variability of the A1, A5 and UE1A Elsburg reefs, obtained at Rand Uranium’s underground mining areas. A total of 133 reef samples, consisting of the Elsburg UE1A, A1 and A5-reefs have been obtained from Cooke 2 and 3 (two of the three Rand Uranium Mines) using the conventional chip sampling method. One of the challenges faced by Rand Uranium Gold Mines in the Cooke section area is the difficulty in differentiating between the various reef types by means of their macroscopic characteristics (colour, pebble types/sizes/shapes, sorting, matrix type, visible sulphide mineralization etc.). This difficulty led to this study which is aimed at utilizing mineral liberation analyzer (MLA)-based automated mineralogy to distinguish between the various reefs and to assess the mineralogical variation within the A1, A5 and UE1A-reefs. The mineralization in this area is hosted by the upper Central Rand Group of the Witwatersrand Supergroup. The main orebodies that are exploited at the mines occur within the Gemsbokfontein Member of the Elsburg Formation. These orebodies have been deformed into an east-west trending anticline at Cooke 3. The present study also attempts to prove or disprove the equivalence of the UE1A-reef on the western limb of the anticline to the A1 or A5-reefs on the eastern limb of the anticline on the basis of mineralogy. Representative splits of the samples were subjected to mineralogical abundance quantification as possible through quantitative MLA-based modal abundance protocols such as XMOD. A standard file on the various mineralogical phases encountered, was created on the 600F MLA and complemented by quantitative XRD (X-ray diffraction) data. Mineral abundances were quantified by MLA, based on integrated backscatter electron (BSE) images and energy dispersive spectrometry (EDS) analyses. Thirty one minerals have been detected using the MLA and they include phases such as quartz, pyrophyllite, chlorite, brannerite, gold, monazite and pyrite as well as minor unknown minerals. Only a few of the minerals are relatively more abundant within the reefs while the majority occurs in very low abundance. Albite, chlorite, muscovite, pyrite, pyrophyllite, quartz, uraninite and zircon are relatively more abundant than the rest of the minerals.
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