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.

L’objectif de la thèse est de comprendre et de modéliser les principaux phénomènes chimiques qui gouvernent les performances du premier réacteur, et en particulier le rôle du solvant donneur d’hydrogène, ainsi que les interactions entre charbon, solvant, hydrogène gazeux et catalyseur. L’impact des conditions opératoires telles que la température, la pression d’hydrogène, le temps de séjour ainsi que l’impact de la qualité de la charge (type de charbon et teneur en cendres) et du type de solvant ont également été évalués. Ce travail s’articule autour d’une partie expérimentale réalisée en autoclave et d’une partie modélisation basée sur un schéma réactionnel simplifié et sur un regroupement par familles chimiques. Dans un premier temps, la partie expérimentale a consisté à mettre au point une stratégie adaptée à l’étude. L’outil utilisé est un réacteur batch de type autoclave fonctionnant jusqu’à 25 MPa et 450°C qui sont des conditions opératoires classiques en hydroliquéfaction du charbon. La charge de référence utilisée est un charbon Illinois n°6, bien connu dans la littérature. Le solvant utilisé est le 1,2,3,4-tétrahydronaphtalène (tétraline) qui est une molécule naphténo-aromatique potentiellement donneuse d’hydrogène et qui a été couramment utilisée au laboratoire pour ce type d’étude. Enfin, un seul catalyseur sulfuré NiMo/Al2O3 a été testé, l’objectif de cette étude ne portant pas sur ce paramètre. Un protocole spécifique de post-traitement a été optimisé pour séparer les différentes fractions de liquéfiats produits, avant leur caractérisation. La démarche originale mise en place dans ce travail a consisté à fractionner les liquéfiats par microdistillation à bande tournante (50 plateaux théoriques) puis à fractionner la coupe résidu sous vide via des extractions par solvants. La microdistillation a ainsi permis de séparer les liquides en quatre coupes : Pi-230°C, 230-350°C,350-450°C et 450°C+, avec une bonne performance de séparation, isolant notamment la quasi totalité du solvant dans la fraction légère, performance difficile à atteindre sur des outils plus classiques. Chacune de ces coupes a été analysée en distillation simulée par chromatographie gazeuse et par analyses élémentaires CHONS. Le résidu sous vide (450°C+) a ensuite été fractionné en huiles lourdes, asphaltènes et préasphaltènes, par solubilité dans l’heptane et le toluène respectivement. Ce protocole a été appliqué à chacun des 66 essais de liquéfaction réalisés dans l’autoclave, ce qui a permis d’effectuer des bilans matières complets et d’évaluer l’impact des conditions opératoires, des interactions solvant-phase gaz-catalyseur et des différentes charges. Pour chaque bilan, le taux deconversion, les structures de rendements et les performances en hydrotraitement ont été déterminés ainsi que la répartition entre la phase gaz et le solvant dans l’hydrogénation du charbon. / This work deals with the understanding and the modeling of coal hydroliquefaction mechanisms, more precisely the impact of operating conditions and H-donor solvent -hydrogen gas phase-catalyst interactions. Experimental tests are performed in a batch reactor by using Illinois #6 coal, tetralin and NiMo/Al2O3 catalyst. An original separation procedure is developped, combinig micor-distillation and solvent extraction. Complete mass balances allow the dtermination of conversion, product yields and product quality. Operating conditions studied are temperature (380° C-420°C), hdrogen pressure (16-22 MPa) and NiMo/Al2O3 presence. Temperatures mainly impacts the firs stage of liquefaction (also called dissolution), hydrogne pressure and catalyst the products quality. Then, tests performed with other solvents (n-undecan or diethylbenzene) and/or under N2 pressure have shown the crucial impact of solvent on the first stage of liquefaction, and and the high impact of gas phase o products quality. These experimental results allow the establishment of kinetic model. In a first step, maceral are transformed into coke, preasphaltenes and hydrotreatment products. Coke formation only depends on temperature. However, preasphaltenes and hydrotreatment products formation highly depends on solvent. Other products (asphaltenes, vacuum distillate, middle distillate, light distillate and gas) are producted from preasphaltenes

No description available.

No description available.

Th. univ.--Sci. phys.--Orléans, 1985. N°: 3.

Metallurgical coke is an important component of the iron and steel industry. It is obtained from high quality coking coals like bituminous coal. However, due to the limited resources and high levels of Green house Gases, alternatives to the product are of high demand. Availability of raw materials is an important factor. The product should have high heating value, strength and lower emissions. Research is being done on form coke technology; to produce high quality substitutes with inexpensive materials like lignite. A biomass-based form coke production process is developed. Two types of raw materials are selected at beginning of process. However, an ideal choice of raw material is evaluated by comparing the quality of the specimens produced from each substance. Various stages of the process are developed and their operating conditions are evaluated. The specimens developed are sent to a test facility to test reactivity and strength after the reaction.

No description available.

O crescente aumento dos preços de carvões de alta qualidade para a coqueificação e sua escassez em todo o mundo tem levado produtores de coque a buscar novas alternativas para a composição de suas misturas. No entanto, mudanças na matriz das misturas de carvões devem ser acompanhadas pela manutenção da qualidade do coque. O presente estudo teve como objetivo geral avaliar a influência do uso de um carvão colombiano médio volátil com alta heterogeneidade, bem como carvões de baixo e alto volátil americanos na qualidade do coque. Para isso esses três carvões e mais dois carvões médio volátil, tipicamente utilizados na produção de coque, foram caracterizados e submetidos a carbonização. Assim foram produzidos em forno piloto (250 kg) coques a partir dos carvões individuais e de três séries de misturas. A caracterização dos coques produzidos foi realizada através de sua análise química, (análises imediata e enxofre), textura óptica, porosidade, resistência mecânica a frio (DI e tambor “I”) e reatividade (CRI e termobalança). Os resultados obtidos apontam que nas condições avaliadas o uso de carvão colombiano em detrimento de carvões de médio volátil teve pouca influência sobre a qualidade do coque até percentuais de 30%, enquanto aumentos maiores afetaram de forma negativa a qualidade do coque. Os limites máximos encontrados para a substituição dos carvões de médio volátil pelos carvões de alto e baixo volátil foram de 30 e 10%, respectivamente. Além disso, foram encontradas e discutidas as relações entre a textura óptica dos coques e sua reatividade, onde a reatividade dos coques aumentou com a diminuição do tamanho da textura óptica dos coques. Verificou-se também que o teste de reatividade em termobalança é uma boa alternativa para a caracterização da reatividade de coques, podendo ser correlacionado a testes padronizados (CRI). O modelo aditivo para a estimativa da textura óptica do coque,com base nos parâmetros dos coques individuais, mostrou uma boa correlação entre os dados experimentais e calcula dos e pode ser usado como uma ferramenta para ajudar na otimização de misturas de carvões. / The increasing price of prime coking coals and their scarcity worldwide have leaded the coke producers to look for alternative ways to compose their coal blends. However, any changes in coal blends should be done follow by the maintenance of the coke quality. The main objective of the present study was to assess the influence of a medium volatile Colombian coal of high heterogeneity, as well as low and high volatile American coals on coke quality. For this propose one Colombian coal of high heterogeneity and four coals typically used as components of coking blends were characterized and submitted to carbonization. Thus, cokes from single coals and three different series of coal blends were produced in a pilot scale coke oven (250kg). Coke characterization was performed by chemical analysis (proximate and sulfur analysis) ,determination of coke optical texture , porosity, mechanical strength tests (DI and I-Type Coke Tumbler) and reactivity tests (thermobalance and CRI)conditions evaluated using. The results showed that the substitution of medium volatile coals by Colombian coal had slight influence on coke quality for percentages equal to or below 30%, whilst further additions had a negative effect on coke quality. The maximum limits found for the replacement of medium volatile for low and high volatile coals were 10 and 30%, respectively. Moreover, the relationship between coke optical texture and reactivity was found and discussed, where coke reactivity increased with decreasing size of the optical texture components. It was also found that the reactivity test carried out in thermobalance is a good alternative for the characterization of coke reactivity and it can be correlated with standardized tests (CRI). The additive model to estimate coke texture, based in individual cokes, showed a good agreement between experimental and calculated data and can be used as a tool to help in the blend composition process.

O crescente aumento dos preços de carvões de alta qualidade para a coqueificação e sua escassez em todo o mundo tem levado produtores de coque a buscar novas alternativas para a composição de suas misturas. No entanto, mudanças na matriz das misturas de carvões devem ser acompanhadas pela manutenção da qualidade do coque. O presente estudo teve como objetivo geral avaliar a influência do uso de um carvão colombiano médio volátil com alta heterogeneidade, bem como carvões de baixo e alto volátil americanos na qualidade do coque. Para isso esses três carvões e mais dois carvões médio volátil, tipicamente utilizados na produção de coque, foram caracterizados e submetidos a carbonização. Assim foram produzidos em forno piloto (250 kg) coques a partir dos carvões individuais e de três séries de misturas. A caracterização dos coques produzidos foi realizada através de sua análise química, (análises imediata e enxofre), textura óptica, porosidade, resistência mecânica a frio (DI e tambor “I”) e reatividade (CRI e termobalança). Os resultados obtidos apontam que nas condições avaliadas o uso de carvão colombiano em detrimento de carvões de médio volátil teve pouca influência sobre a qualidade do coque até percentuais de 30%, enquanto aumentos maiores afetaram de forma negativa a qualidade do coque. Os limites máximos encontrados para a substituição dos carvões de médio volátil pelos carvões de alto e baixo volátil foram de 30 e 10%, respectivamente. Além disso, foram encontradas e discutidas as relações entre a textura óptica dos coques e sua reatividade, onde a reatividade dos coques aumentou com a diminuição do tamanho da textura óptica dos coques. Verificou-se também que o teste de reatividade em termobalança é uma boa alternativa para a caracterização da reatividade de coques, podendo ser correlacionado a testes padronizados (CRI). O modelo aditivo para a estimativa da textura óptica do coque,com base nos parâmetros dos coques individuais, mostrou uma boa correlação entre os dados experimentais e calcula dos e pode ser usado como uma ferramenta para ajudar na otimização de misturas de carvões. / The increasing price of prime coking coals and their scarcity worldwide have leaded the coke producers to look for alternative ways to compose their coal blends. However, any changes in coal blends should be done follow by the maintenance of the coke quality. The main objective of the present study was to assess the influence of a medium volatile Colombian coal of high heterogeneity, as well as low and high volatile American coals on coke quality. For this propose one Colombian coal of high heterogeneity and four coals typically used as components of coking blends were characterized and submitted to carbonization. Thus, cokes from single coals and three different series of coal blends were produced in a pilot scale coke oven (250kg). Coke characterization was performed by chemical analysis (proximate and sulfur analysis) ,determination of coke optical texture , porosity, mechanical strength tests (DI and I-Type Coke Tumbler) and reactivity tests (thermobalance and CRI)conditions evaluated using. The results showed that the substitution of medium volatile coals by Colombian coal had slight influence on coke quality for percentages equal to or below 30%, whilst further additions had a negative effect on coke quality. The maximum limits found for the replacement of medium volatile for low and high volatile coals were 10 and 30%, respectively. Moreover, the relationship between coke optical texture and reactivity was found and discussed, where coke reactivity increased with decreasing size of the optical texture components. It was also found that the reactivity test carried out in thermobalance is a good alternative for the characterization of coke reactivity and it can be correlated with standardized tests (CRI). The additive model to estimate coke texture, based in individual cokes, showed a good agreement between experimental and calculated data and can be used as a tool to help in the blend composition process.

O crescente aumento dos preços de carvões de alta qualidade para a coqueificação e sua escassez em todo o mundo tem levado produtores de coque a buscar novas alternativas para a composição de suas misturas. No entanto, mudanças na matriz das misturas de carvões devem ser acompanhadas pela manutenção da qualidade do coque. O presente estudo teve como objetivo geral avaliar a influência do uso de um carvão colombiano médio volátil com alta heterogeneidade, bem como carvões de baixo e alto volátil americanos na qualidade do coque. Para isso esses três carvões e mais dois carvões médio volátil, tipicamente utilizados na produção de coque, foram caracterizados e submetidos a carbonização. Assim foram produzidos em forno piloto (250 kg) coques a partir dos carvões individuais e de três séries de misturas. A caracterização dos coques produzidos foi realizada através de sua análise química, (análises imediata e enxofre), textura óptica, porosidade, resistência mecânica a frio (DI e tambor “I”) e reatividade (CRI e termobalança). Os resultados obtidos apontam que nas condições avaliadas o uso de carvão colombiano em detrimento de carvões de médio volátil teve pouca influência sobre a qualidade do coque até percentuais de 30%, enquanto aumentos maiores afetaram de forma negativa a qualidade do coque. Os limites máximos encontrados para a substituição dos carvões de médio volátil pelos carvões de alto e baixo volátil foram de 30 e 10%, respectivamente. Além disso, foram encontradas e discutidas as relações entre a textura óptica dos coques e sua reatividade, onde a reatividade dos coques aumentou com a diminuição do tamanho da textura óptica dos coques. Verificou-se também que o teste de reatividade em termobalança é uma boa alternativa para a caracterização da reatividade de coques, podendo ser correlacionado a testes padronizados (CRI). O modelo aditivo para a estimativa da textura óptica do coque,com base nos parâmetros dos coques individuais, mostrou uma boa correlação entre os dados experimentais e calcula dos e pode ser usado como uma ferramenta para ajudar na otimização de misturas de carvões. / The increasing price of prime coking coals and their scarcity worldwide have leaded the coke producers to look for alternative ways to compose their coal blends. However, any changes in coal blends should be done follow by the maintenance of the coke quality. The main objective of the present study was to assess the influence of a medium volatile Colombian coal of high heterogeneity, as well as low and high volatile American coals on coke quality. For this propose one Colombian coal of high heterogeneity and four coals typically used as components of coking blends were characterized and submitted to carbonization. Thus, cokes from single coals and three different series of coal blends were produced in a pilot scale coke oven (250kg). Coke characterization was performed by chemical analysis (proximate and sulfur analysis) ,determination of coke optical texture , porosity, mechanical strength tests (DI and I-Type Coke Tumbler) and reactivity tests (thermobalance and CRI)conditions evaluated using. The results showed that the substitution of medium volatile coals by Colombian coal had slight influence on coke quality for percentages equal to or below 30%, whilst further additions had a negative effect on coke quality. The maximum limits found for the replacement of medium volatile for low and high volatile coals were 10 and 30%, respectively. Moreover, the relationship between coke optical texture and reactivity was found and discussed, where coke reactivity increased with decreasing size of the optical texture components. It was also found that the reactivity test carried out in thermobalance is a good alternative for the characterization of coke reactivity and it can be correlated with standardized tests (CRI). The additive model to estimate coke texture, based in individual cokes, showed a good agreement between experimental and calculated data and can be used as a tool to help in the blend composition process.