[pt] O Ácido Húmico (AH) é uma fração orgânica obtida em solos, corpos hídricos bem como em matrizes carbonáceas. Nos últimos anos o interesse associado a esta substância vem crescendo progressivamente à medida que novas aplicações são descobertas, tais como: fertilizantes, recuperação de áreas degradadas e tratamento de efluentes contaminados com metais. As principais características dos AH são dependentes do método de extração e da matriz escolhida, posto que se pode extraí-lo de uma ampla gama de matérias primas, assim como por meio de diferentes métodos. Dentro deste contexto, o objetivo principal do presente trabalho pretende avaliar o potencial de extração de ácido húmico a partir de diferentes precursores carbonáceos. Foram utilizadas três matrizes carbonáceas distintas: rejeito de carvão mineral (RCM), coque mineral (CM) e coque verde de petróleo (CVP). Além deste estudo experimental foram apresentados alguns resultados de estudo semelhante disponível na literatura. O método de extração utilizado foi adaptado de Trompowski et al (2005), e a caracterização foi feita utilizando-se técnicas de ICP-OES, CNHS, MEV/EDS, FTIR e Difração de Raio-X. A eficiência da extração, em termos de recuperação em massa, variou, significativamente, em função do método adotado, sendo os melhores resultados associados ao rejeito de carvão mineral (17,0 porcento), ao passo que a menor eficiência está relacionada ao coque verde de petróleo, após destilação (0,2 porcento). A extração a partir do coque verde de petróleo, como recebido, é inviável em função da sua imiscibilidade com a solução de ácido nítrico. Os resultados obtidos a partir do FTIR foram satisfatórios para todos os AH analisados, apresentando bandas características de AH e compatíveis com o indicado na literatura. Os resultados da análise de ICP-OES apresentaram baixa presença de metais e elementos traços para o AH oriundo do coque mineral. No que diz respeito ao ácido húmico extraído do rejeito de carvão mineral, que apresentou a maior concentração inicial de metais, principalmente ferro, foi implementado, com sucesso, uma purificação utilizando ácido nítrico. Com base nos resultados obtidos é possível afirmar que a utilização de diferente precursores carbonosos permitiu a extração de AH com características semelhantes aqueles citados na literatura e extraídos de outras fontes. / [en] The humic acid (HA) is an organic fraction that can be found in soil and watercourses as well as in carbonaceous matrices. In recent years the interest associated with this substance has been growing steadily as new applications are discovered, such as fertilizers, remediation of degraded areas and treatment of wastewater contaminated with metals. The main features of HA are dependent on the method of extraction and the chosen matrix, since it can be extract from a wide range of raw materials, as well as by different methods. Within this context, the main objective of this work is related to an assessment of the potential of extracting humic acid from different carbonaceous precursors. three different carbonaceous matrices were used: coal tailings (RCM), coke (CM) and green petroleum coke (CVP). Besides this experimental study some results of a similar study available in the literature were presented. The extraction method used was adapted from Trompowski et al, and the characterization was done using ICP- OES techniques, CNHS, MEV / EDS and FTIR. The extraction efficiency, in terms of mass recovery, significantly varied depending on the method used, the best results being associated with coal tailings (17.0 percent), while lower efficiency relates to the calcinated petrocoke after distillation (0.2 percent). The extraction from green petroleum coke, as received, is unfeasible due to its immiscibility with the nitric acid solution. The results obtained from FTIR were satisfactory for all the HA analyzed, displaying bands consistent with those from HA and compatible with bands shown in the literature. The results of the analysis of ICP-OES showed a low presence of metals and trace elements coming from the HA for coke. With respect to the extracted humic acid from coal tailings, which showed the highest initial concentration of metals, particularly iron, was successfully implemented, a purification with nitric acid. Based on the results obtained it can be stated that the use of different carbonaceous precursors allowed the extraction of humic acid with similar characteristics as cited in the literature and those obtained from other sources.

Gasification is a process used to convert any carbonaceous species through heterogeneous reaction to obtain the desired gaseous products of H2 and CO which are used to make chemicals, liquid transportation fuels, and power. Both pyrolysis and heterogeneous gasification occur in commercial entrained-flow gasifiers at pressures from 4 to 65 atm with local gas temperatures as high as 2000 °C. Many gasification studies have been performed at moderate temperatures, heating rates, and pressures. In this work, both pyrolysis and char gasification experiments were performed on coal, petroleum coke, and biomass at conditions pertinent to commercial entrained-flow gasifiers. Rapid biomass pyrolysis experiments were performed at atmospheric pressure in an entrained-flow reactor for sawdust, switchgrass, corn stover, and straw mostly using a peak gas temperature of 1163 K at particle residence times ranging from 34 to 113 ms. Biomass pyrolysis was modeled using the Chemical Percolation Devolatilization model assuming that biomass pyrolysis occurs as a weighted average of its individual components (cellulose, hemicellulose, and lignin). Thermal cracking of biomass tar into light gas was included using a first-order model with kinetic parameters regressed in the current study. Char gasification rates were measured for biomass, petroleum coke, and coal in a pressurized entrained-flow reactor at high heating-rate conditions at total pressures between 10 and 15 atm. Peak centerline gas temperatures were between 1611 and 1879 K. The range of particle residence times used in the gasification experiments was 42 to 275 ms. The CO2 gasification rates of biomass and petroleum coke chars were measured at conditions where the reaction environment consisted of approximately 40 and 90 mol% CO2. Steam gasification rates of coal char were measured at conditions where the maximum H2O concentration was 8.6 mol%. Measured data was used to regress apparent kinetic parameters for a first-order model that describes char conversion. The measured char gasification rates were far from the film-diffusion limit, and are pertinent for pulverized particles where no internal particle temperature gradients are important. The modeling and measured data of char gasification rates in this research will aid in the design and efficient operation of commercial entrained-flow gasifiers, as well as provide validation for both existing and future models at a wide range of temperatures and pressures at high heating-rate conditions.

Nesta tese foram desenvolvidos procedimentos analíticos fotométricos automáticos para determinação simultânea de sulfato e cloreto em coque de petróleo, molibdênio em plantas sem etapa de pré-concentração com solvente orgânico e zinco em águas empregando microextração líquido-líquido. Em todos os procedimentos reportados nesta tese, o módulo de análise foi baseado no processo de multicomutação, utilizou-se bomba de seringa como propulsor de fluidos e válvulas solenoide de três vias como dispositivos de comutação para controlar as inserções das alíquotas da amostra e dos reagentes no percurso analítico. As detecções fotométricas foram realizadas empregando fotômetros de LEDs, construídos para este projeto, equipados com celas de fluxo com caminho óptico longo (50,0 mm para cloreto, sulfato e zinco, 200,0 mm para molibdênio). O fotômetro foi construído com LEDs de alto brilho como máximos de emissão em 472 nm para cloreto, sulfato e molibdênio e 525 nm para zinco. Os procedimentos para determinação simultânea de sulfato e cloreto apresentaram faixa linear entre 10-700 mg L-1; 0,25-10 mg L-1; limite de detecção de 5,3 mg L-1; 0,16 mg L-1; coeficiente de variação de 3,0%; 0,9 % (n=10), respectivamente, e frequência de amostragem de 75 determinações por hora para cada analito. O procedimento para determinação de molibdênio apresentou faixa linear entre 50 - 500 ?g L-1, limite de detecção 9,1 ?g L-1, coeficiente de variação 1,07% (n=10) e frequência de amostragem de 51 determinações por hora. O procedimento para zinco apresentou uma faixa linear entre 10-100 ?g L-1, limite de detecção 8,3 ?g L-1, coeficiente de variação 3,3% (n=10) e frequência de amostragem de 19 determinações por hora / In this thesis, automated photometric analytical procedures for simultaneous determination of sulfate and chloride in petroleum coke, molybdenum in plants without pre-concentration step and zinc in water using liquid-liquid microextraction were developed. All procedures reported in this thesis, employed flow analysis modules based on multicommuted process, syringe pump for fluid propulsion and solenoid three-way valves as commutation devices the insertion aliquots of sample and reagents solutions in the analytical path. Photometric detections were performed, using LEDs-photometers, built for this project, equipped with flow cells with long optical path (50.0 mm for chloride, sulfate and zinc, 200.0 mm for molybdenum) and the high intense radiation beam LEDs with maximum emission at 472 nm for chloride, sulfate and molybdenum and 525 nm for zinc. The procedures for simultaneous determination of sulfate and chloride showed linear response between 10 to 700 mg L-1; 0.25 to 10 mg L-1; detection limit of 5.3 mg L-1; 0.16 mg L-1; variation coefficient of 3.0%; 0.9% (n = 10), respectively, and sampling throughput of 75 determinations per hour for each analyte. The procedure for molybdenum presented a linear response between 50 to 500 ?g L-1, detection limit of 9.1 ?g L-1, variation coefficient of 1.07% (n = 10) and sampling throughput of 51 determinations per hour. The procedure for zinc showed linear response between 10 to 100 ?g L-1, detection limit of 8.3 ?g L-1, variation coefficient of 3.3% (n = 10) and sampling throughput of 19 determinations per hour

Nesta tese foram desenvolvidos procedimentos analíticos fotométricos automáticos para determinação simultânea de sulfato e cloreto em coque de petróleo, molibdênio em plantas sem etapa de pré-concentração com solvente orgânico e zinco em águas empregando microextração líquido-líquido. Em todos os procedimentos reportados nesta tese, o módulo de análise foi baseado no processo de multicomutação, utilizou-se bomba de seringa como propulsor de fluidos e válvulas solenoide de três vias como dispositivos de comutação para controlar as inserções das alíquotas da amostra e dos reagentes no percurso analítico. As detecções fotométricas foram realizadas empregando fotômetros de LEDs, construídos para este projeto, equipados com celas de fluxo com caminho óptico longo (50,0 mm para cloreto, sulfato e zinco, 200,0 mm para molibdênio). O fotômetro foi construído com LEDs de alto brilho como máximos de emissão em 472 nm para cloreto, sulfato e molibdênio e 525 nm para zinco. Os procedimentos para determinação simultânea de sulfato e cloreto apresentaram faixa linear entre 10-700 mg L-1; 0,25-10 mg L-1; limite de detecção de 5,3 mg L-1; 0,16 mg L-1; coeficiente de variação de 3,0%; 0,9 % (n=10), respectivamente, e frequência de amostragem de 75 determinações por hora para cada analito. O procedimento para determinação de molibdênio apresentou faixa linear entre 50 - 500 ?g L-1, limite de detecção 9,1 ?g L-1, coeficiente de variação 1,07% (n=10) e frequência de amostragem de 51 determinações por hora. O procedimento para zinco apresentou uma faixa linear entre 10-100 ?g L-1, limite de detecção 8,3 ?g L-1, coeficiente de variação 3,3% (n=10) e frequência de amostragem de 19 determinações por hora / In this thesis, automated photometric analytical procedures for simultaneous determination of sulfate and chloride in petroleum coke, molybdenum in plants without pre-concentration step and zinc in water using liquid-liquid microextraction were developed. All procedures reported in this thesis, employed flow analysis modules based on multicommuted process, syringe pump for fluid propulsion and solenoid three-way valves as commutation devices the insertion aliquots of sample and reagents solutions in the analytical path. Photometric detections were performed, using LEDs-photometers, built for this project, equipped with flow cells with long optical path (50.0 mm for chloride, sulfate and zinc, 200.0 mm for molybdenum) and the high intense radiation beam LEDs with maximum emission at 472 nm for chloride, sulfate and molybdenum and 525 nm for zinc. The procedures for simultaneous determination of sulfate and chloride showed linear response between 10 to 700 mg L-1; 0.25 to 10 mg L-1; detection limit of 5.3 mg L-1; 0.16 mg L-1; variation coefficient of 3.0%; 0.9% (n = 10), respectively, and sampling throughput of 75 determinations per hour for each analyte. The procedure for molybdenum presented a linear response between 50 to 500 ?g L-1, detection limit of 9.1 ?g L-1, variation coefficient of 1.07% (n = 10) and sampling throughput of 51 determinations per hour. The procedure for zinc showed linear response between 10 to 100 ?g L-1, detection limit of 8.3 ?g L-1, variation coefficient of 3.3% (n = 10) and sampling throughput of 19 determinations per hour

Physical activation of oil-sands fluid coke, a dense carbonaceous material, using sulfur dioxide (SO2) was investigated as a means of utilizing a plentiful and inexpensive waste for elemental mercury (Hg) removal. A new model was developed to elucidate physical activation of dense carbonaceous materials. Experiments and model simulations revealed that, during activation with SO2, a sulfur-rich porous layer is formed around the periphery of the coke particles; this porous layer reaches a maximum thickness as a result of diffusion limitations; the maximum porous layer thickness is controlled by activation conditions and determines the maximum achievable specific surface area (SSA). Pre-oxidation in air prior to activation, acid washing after activation and smaller coke particle size all result in higher SSA. The highest SSA achieved was 530 m2/g, the highest yet found for oil-sands fluid coke with physical activation. If present, oxygen out-competed SO2 for carbon during activation. SO2 activation and porous layer formation did not occur until oxygen was depleted. Sulfur added to coke through SO2 activation is mainly in reduced forms which are more thermally stable than elemental sulfur in commercial sulfur-impregnated activated carbons (SIACs). TGA and elemental analyses revealed that only 17% of sulfur was removed at 800°C from SO2-activated coke under inert conditions, compared with 100% from a commercial SIAC. The role of sulfuric acid (H2SO4) in vapor Hg capture by activated carbon (AC) was studied due to conflicting findings in the recent literature. In the absence of other oxidizing species, it was found that Hg could be oxidized by oxygen which enhanced vapor Hg adsorption by AC and Hg absorption in H2SO4 solution at room and elevated temperatures. At 200°C, AC treated with 20% H2SO4 reached a Hg loading of more than 500 mg/g, which is among the highest Hg capacities yet reported. When oxygen was not present, S6+ in H2SO4 was found to act as an oxidizer of Hg, thus enabling Hg uptake by H2SO4-treated AC at 200°C. Treating the AC with SO2 at 700°C improved the initial rate of Hg uptake, with and without subsequent H2SO4 treatment.

Physical activation of oil-sands fluid coke, a dense carbonaceous material, using sulfur dioxide (SO2) was investigated as a means of utilizing a plentiful and inexpensive waste for elemental mercury (Hg) removal. A new model was developed to elucidate physical activation of dense carbonaceous materials. Experiments and model simulations revealed that, during activation with SO2, a sulfur-rich porous layer is formed around the periphery of the coke particles; this porous layer reaches a maximum thickness as a result of diffusion limitations; the maximum porous layer thickness is controlled by activation conditions and determines the maximum achievable specific surface area (SSA). Pre-oxidation in air prior to activation, acid washing after activation and smaller coke particle size all result in higher SSA. The highest SSA achieved was 530 m2/g, the highest yet found for oil-sands fluid coke with physical activation. If present, oxygen out-competed SO2 for carbon during activation. SO2 activation and porous layer formation did not occur until oxygen was depleted. Sulfur added to coke through SO2 activation is mainly in reduced forms which are more thermally stable than elemental sulfur in commercial sulfur-impregnated activated carbons (SIACs). TGA and elemental analyses revealed that only 17% of sulfur was removed at 800°C from SO2-activated coke under inert conditions, compared with 100% from a commercial SIAC. The role of sulfuric acid (H2SO4) in vapor Hg capture by activated carbon (AC) was studied due to conflicting findings in the recent literature. In the absence of other oxidizing species, it was found that Hg could be oxidized by oxygen which enhanced vapor Hg adsorption by AC and Hg absorption in H2SO4 solution at room and elevated temperatures. At 200°C, AC treated with 20% H2SO4 reached a Hg loading of more than 500 mg/g, which is among the highest Hg capacities yet reported. When oxygen was not present, S6+ in H2SO4 was found to act as an oxidizer of Hg, thus enabling Hg uptake by H2SO4-treated AC at 200°C. Treating the AC with SO2 at 700°C improved the initial rate of Hg uptake, with and without subsequent H2SO4 treatment.