ResumoA utilização de carvão vegetal em substituição a outros materiais de origem fóssil na produção de coque é uma das alternativas para mitigar as emissões de CO2 na siderurgia. Contudo, a inserção de carvão vegetal na coqueificação apresenta fortes limitações, as quais estão principalmente associadas à sua elevada reatividade ao CO2. Assim, o presente estudo visou investigar alternativas para diminuir a reatividade do carvão vegetal. Para isso foram investigados os efeitos da temperatura de pirólise, desmineralização e impregnação por alcatrão. Os resultados mostraram que o aumento da temperatura de pirólise diminui a reatividade do carvão vegetal. Essa mesma tendência foi também observada ao se remover os componentes inorgânicos do carvão vegetal e ao se impregnar a sua estrutura com alcatrão. A associação dos tratamentos térmico, de desmineralização e impregnação com alcatrão resultou em reduções de reatividade na ordem de até 6 vezes a do material inicial.
The use of charcoal in the production of coke is one of the alternatives to mitigate CO2 emissions in the steel industry. However, the addition of charcoal in cokemaking has severe limitations, which are mainly associated with its high reactivity to CO2. In previous works, the impregnation of charcoal by tar proved to be a promising mechanism in the attempt to insert this material. This work aimed at incresing the knowledge about the technique of impregnation of tar on the charcoal evaluating its efficiency and influence on the reactivity to CO2. For this purpose, the morphology of charcoal particles impregnated with tar was investigated by microscopy while the reactivity of this material was analyzed through thermogravimetric tests. As a result, impregnation directly reflects a decrease in the surface area of the charcoal particle and, consequently, a decrease in CO2 reactivity of the impregnated charcoal. This behavior was mainly attributed to the decrease in surface area caused by the impregnation and the intrinsic behavior of low reactivity of the pyrolyzed tar, thus forming an effective barrier against the gasification of the material.
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