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Authors: Kronbauer, Márcio André
Title: Geoquímica das fases cristalinas e vítreas provenientes das cinzas de gaseificação de carvões minerais
Keywords: Nanoparticles morphology;Hazardous elements;Coal;Ashes;Avaliação de Impactos Ambientais;Nanopartículas morfológicas;Elementos perigosos;Carvão;Cinzas
Issue Date: 2013
Publisher: Centro Universitário La Salle
Abstract: Combined cycle technology was initially developed to operate on natural gas. Currently, it has been adapted to operate with coal and other fuels, giving rise to what is known as combustion technology / integrated gasification combined cycle. Typically, Integrated Gasification Combined Cycle (IGCC) plants use two engines, one gas and one steam. A gas turbine requires a gas clean of contaminants. This allows for a clean use of coal with a high energy efficiency and low emission of gases and particles. During the next few years an increase in the number of central GICC in operation is expected, with a consequent increase in the production of IGCC byproducts. Additionally, the technology is characterized by IGCC operating conditions (reducing environment, high temperature and pressure, as well as high flexibility in fuel) completely different from pulverized coal (PC) plants. Thus, the expected behavior and composition of trace elements is very different in IGCC byproducts. Therefore, in targeting potential applications, it is necessary to broaden the knowledge of these aspects for the recovery of IGCC byproducts. However, mineralogical and chemical ashes from coal gasification have not been as extensively studied as the products of pulverized coal combustion, which are widely used. We studied the solid waste gasification of coals with levels ranging from low- to medium-sulfur inertinite-rich, high volatile A bituminous coal, and high-sulfur content, vitrinite-rich, high volatile C bituminous coal. The petrology of the ash usually reflects the classification singular and maceral composition of coals food with a higher ranking for coal with high inertinite with anisotropic and inertinite-carbons in gray, and the lower classification derived from waste containing isotropic carbons. The chemical composition of coal-feed mineralogy determines the amorphous and mineral composition of the ash phase, the non-carbonaceous portion of the waste, with the proportions of CaCO3 against Al2O3 determining the trend for the neoformation of anorthite versus mullite, respectively. Furthermore, the gaseous species of As and Sb droplets react with sulfides of Fe-Ni (W-Co-Cu) in the molten state segregated on the surface of fly ash formation, giving rise to nickeline (NiAs)-breithauptite (NiSb) with impurities of Fe and S. The drops of sulfides of Fe-Ni (WCo-Cu) also crystallize as Pyrrhotite Millerite. All these stages can be oxidized or reduced hydrolyzed during the cooling of the gas. All of these crystalline phases are extracted from the gasifier together with the fly ash particles. Additionally, electron 8 microscopy studies show the presence of large numbers of nanoparticles with potentially hazardous elements.
metadata.dc.contributor.advisor: Oliveira, Luís Felipe Silva
metadata.dc.contributor.advisorco: Oliveira, Marcos Leandro Silva
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