O aproveitamento da palha do café por meio da conversão térmica apresenta-se com uma alternativa para o problema ambiental de descarte e queimadas a céu aberto, evitando a emissão dos gases poluentes na atmosfera, mais conhecidos como gases do efeito estufa (GEE), agregando valor aos resíduos. A palha do café, também conhecida como casca do café, foi utilizada in natura, e submetida à pirólise em reator de leito fixo, em escala laboratorial. Os experimentos foram realizados em sistema de bateladas, uma vez que o equipamento é totalmente fechado; a massa de palha do café utilizada foi de 54g e parâmetros como pressão de alimentação do gás de aquecimento (5,5 Kgf/cm2), taxa de aquecimento (20 °C/min), temperatura de operação do reator de pirólise (Tmáx = 708 0C) e rendimento gravimétrico tanto da fase sólida quanto da fase líquida, foram estudados definindo as melhores condições de controle do processo. Várias caracterizações utilizando as seguintes técnicas: análise imediata, análise elementar, análise térmica (TG/DTG e DSC) e GC/MS foram realizadas com a palha do café, para que fossem inferidos parâmetros de partida para a pirólise da biomassa. Os produtos sólido (cinzas), líquido (bio-óleo) e gasoso foram coletados avaliando-se os rendimentos e relacionando-os com os parâmetros previamente estabelecidos, sendo submetidos a análises com o objetivo de obter informações que possam contribuir para a sua melhor utilização. Quanto à caracterização dos produtos sólidos, os mesmos apresentaram alto poder calorífico, podendo ser utilizado como combustível. A fração liquida é composta basicamente de hidrocarbonetos oxigenados e aromáticos, caracterizando o bio-óleo como insumo para indústria química. O hidrogênio, objetivo deste trabalho, foi obtido em frações significativas e os resultados mostraram que a temperatura, bem como a taxa de aquecimento influem no rendimento do mesmo. / The use of coffee straw through the thermal conversion is presented as an alternative to the environmental problem of disposal and burning in the open, avoiding the emission of greenhouse gases in the atmosphere, better known as greenhouse gases (GHGs), and adding value to waste. The coffee straw, also known as \"shell\" coffee, was used in nature, and subjected to a fixed bed pyrolysis reactor at laboratory scale. The experiments were carried out in batch system, once the equipment is completely closed; the coffee straw weight used was about 54g and parameters such as feed pressure process (5.5 kgf/cm2), heating rate (20 0C/min), the operating temperature pyrolysis reactor (Tmax = 708 °C) and gravimetric yield of both the solid phase and liquid phase were studied by defining the best conditions for the process control. Several characterizations using the following techniques: proximate analysis, elemental analysis (CHN), thermal analysis (TG / DTG and DSC), and GC-MS analysis were performed with coffee straw, to be inferred starting parameters for the pyrolysis of biomass. The solid product (ash), liquid (bio-oil) and gases were collected by assessing incomes and linking them with the previously established parameters, being subjected to analysis in order to obtain information that can contribute to improved utilization. The solid products characterization, presented a high calorific value and can be used as fuel. The liquid fraction is composed primarily of aromatics and oxygenated hydrocarbons, characterizing the bio-oil as a feedstock for chemical industry. Hydrogen, objective of this study was obtained in significant fractions, the results showed that the temperature and the heating rate improves the hydrogen yield.

O bambu e uma graminea lenhosa, renovavel, perene e com boa produtividade de biomassa por hectare. Pode ser cultivada praticamente em todo o territorio brasileiro, que esta quase todo localizado em regioes tropicais e chuvosas, oferecendo excelentes condicoes para a producao e o uso energetico da biomassa de bambu em larga escala. O setor de papel e celulose apresenta boas perspectivas na producao de papel de fibras longas utilizando bambu, no entanto, apenas duas empresas brasileiras utilizam esse tipo de biomassa em grande escala no Brasil: O Grupo Penha queima o bambu em caldeira e utiliza o vapor no processo de reciclagem de papel e O Grupo Joao Santos utiliza a biomassa como materia prima na fabricacao de papel e celulose. No entanto, em ambos os casos a biomassa nao e utilizada em sistema de cogeracao de eletricidade, considerada uma tecnologia eficiente de conversao. O objetivo dessa tese e estudar os aspetos tecnicos, economicos e ambientais da implantacao de um sistema de cogeracao de eletricidade utilizando biomassa de bambu. Sao estudadas as caracteristicas agronomicas e as particularidades da implantacao de cultivos comerciais de bambu voltado a fins energeticos. Visando determinar o Poder Calorifico (PCS) de cinco diferentes especies consideradas adaptadas ao clima brasileiro e conhecidas como boas produtoras de biomassa por hectare, foram realizado ensaios em laboratorio empregando a bomba calorimetrica, possibilitando identificar variacoes do poder calorifico entre as especies estudadas. Considerando o dado referente aos processos das empresas e pesquisa em literatura, os resultados apontam que e tecnicamente possivel cogerar eletricidade de modo eficiente, queimando 17 toneladas de bambu por hora e gerar 3.5 MW. No entanto, o sistema nao apresenta viabilidade economica em funcao do modelo de atual adotado pelas empresas no manejo de seus cultivos. Em relacao aos aspectos ambientais, por ser uma planta perene, capaz de produzir biomassa anualmente sem replantio, pode ser uma excelente opcao para estocar carbono. / Bamboo is a grass, woody perennial with good biomass productivity per hectare. Bamboo can be grown virtually anywhere in the Brazilian territory and almost all existing plantations are located in tropical and rainy areas, offering excellent conditions for the production and use of biomass energy in large scale. Two Brazilian companies already utilize bamboo biomass in large scale in Brazil. The Penha Group, in Bahia, burns bamboo in boilers and uses the steam in the process for recycling paper. Joao Santos Group uses bamboo as raw material in the manufacture of pulp and paper. However in any case there is the use of this biomass for energy cogeneration, which is the most efficient technology for energy conversion. Therefore, this thesis analyses the use of bamboo as fuel for electricity cogeneration in Brazil considering the technical aspects, as well as the corresponding economic and environmental system deployment. Also, to study the development of the productive chain of bamboo in large scale in Brazil, specifically targeted for energy purposes, this paper presents the survey of data concerning the different production systems adopted by companies, both in the cultivation and processing of biomass. Based in these results it is analyzed an efficient cogeneration system using bamboo as fuel on large scale. Obtained results show that the power to be produced in an efficient cogeneration system (60 bar, 490 oC), from 17 tones of bamboo per hour, is 3,5 MW but, with the existing bamboo production models, there is no economic feasibility, as discussed in the paper. Regarding environmental aspects, it must be noted that the bamboo is as perennial plant, able to produce biomass annually without replanting, and so appears to be an excellent carbon sink.

Insufficient knowledge of fireside behavior in the near-burner region during biomass combustion is one of major factors preventing widespread use of this renewable fuel in pulverized coal power plants. The current research is aimed to investigate the impact of biomass cofiring on NO formation in the near-burner region through interpretation of computational fluid dynamics (CFD) predictions and data collected from a series of biomass tests in a pilot-scale (0.2 MW), swirling flow burner. Two-dimensional gas species mole fraction data were collected with state-of-theart instruments from nine experiments, composing one herbaceous biomass (straw), one woody biomass (sawdust), a low sulfur sub-bituminous coal (Blind Canyon) and a high sulfur bituminous coal (Pittsburgh #8) and their mixtures of different mass fractions with the same swirl setting. Velocity and temperature are calculated from CFD modeling with FLUENTTM, supplemented with hot-wire anemometer measurements. For the first time, a reverse flow region was predicted during solid fuel combustion simulations for the reactor used. Interpretation of the results was carried on with two original methods: stoichiometric maps and normalized species mole fraction profiles. The impacts of biomass on combustion in the swirling flows were analyzed from several aspects: aerodynamics, fuel properties (particle size, volatile content, and fix-carbon content), and NO formation routes. The species maps show the low-grade fuel combustion under swirling flows is composed of two zones: a high species-gradient combustion region attached to the inlet and flat-profiles dominant across the rest of the reactor. Results from tests involving biomass clearly demonstrate the expansion of the combustion region. CFD calculations demonstrate that there is no obvious alteration of the reverse-flow region by biomass combustion. The larger average particle size of biomass generates a combustion region with further penetration into the reactor. In certain tests involving biomass, more NH3 than HCN was detected in several biomass experiments, though limited by the data collection method and low fuel-nitrogen fuels used (sawdust). Supplemented with kinetic calculations with CHEMKIN, it was found that NO formation is dependent on the nitrogen forms in the parent fuels.

Recently, there has been growing interest in the green synthesis of zeolite (aluminosilicate) materials using solvent-free synthesis methods. Solid starting materials are typically ground for a period of time followed by thermal heating to synthesize crystalline ZSM-5 zeolite. These studies generally have focused on products formed after the thermal heating. However, very little is known about the reaction intermediates formed during the mechanochemical pre-reaction grinding step and how the pre-reaction impacts the subsequent synthetic success. In this study, the mechanochemical approach used to synthesize ZSM-5 and mordenite zeolite was investigated. Two types of solvent-free synthesis methods were investigated; templated solvent-free synthesis, and template-free and solvent-free synthesis. The effect of grinding time was investigated first to find the optimal grinding time that initiates pre-reactions between the starting materials. Controlled experiments were used to monitor chemical and physical changes occuring during the grinding step. Subsequently, the effect of different synthesis conditions such as time, temperature, template, SiO2/Al2O3, and Na2O/Al2O3 ratios, and different precursors were studied using the optimal grinding time. Both manual (mortar and pestle) and ball mill (FTS 1000) grinding were used in this study. The synthesized products were characterized using XRD, BET nitrogen adsorption, SEM, and ICP-OES. Finally, selected single-phase synthesized zeolite materials were evaluated for their catalytic performance in biomass conversion process of cellulose and glucose to useful chemicals such as hydroxymethylfurfural (HMF).

In the context of the ESA BIOMASS mission in which for the first time, a P-Band SAR sensor isgoing to be mounted into a spaceborne system. With its penetration capability, it will contributeto the measurement of the biomass and carbon content in the Earth’s forests. An autofocusalgorithm is needed for the correction of phase errors introduced by the changing diffraction indexin the ionosphere. Because of the quickly changing nature of the ionosphere, defocusing has to bemeasured and corrected locally over several sections of a SAR capture.In this thesis, a deep introduction into phase errors is made having in mind that the ionosphereis expected to introduce time varying low frequency errors that can be constructed as a series ofquadratic curves. These quadratic phase errors introduce defocusing that is seen as blur and lossof contrast. An algorithm is proposed and tested for measuring this defocusing, while its strengthsand weaknesses are discussed.The idea of measuring defocusing is to try to recover the temporal phase function that introduceddefocusing in the first place. Here a method to recover this temporal phase function is introduced,and a thorough performance assessment of this retrieval is carried out. The variables involved thequality and reliability of this retrieval are studied one by one.

Avalanche paths are unique ecosystems that represent a significant portion of the landscape in the northern Rocky Mountains. Frequent avalanche disturbance results in vegetative cover that is unlike the adjacent coniferous forest. These high relief environments have the potential to remove carbon from the atmosphere at rates differing from those of the surrounding forest, and to regulate matter and/or energy fluxes to downslope ecosystems. This thesis attempts to estimate organic carbon on south-facing avalanche paths in the southern portion of Glacier National Park, Montana. I am specifically interested in total organic carbon density, compartmental carbon density, and change in organic carbon over time as a function of shrub and tree diameter. Using an integrated sampling method, estimates of total organic carbon on avalanche paths appear to be different than those of the adjacent forest and similar to those of other shrub formation types in the area. However, the potentially moveable litter compartment is consistently larger. Organic carbon from shrub and trees growing on paths appears to be increasing at a continuous rate leading up to disturbance, while a typical individual's rate of increase appears to be slowing. The organic material temporarily stored on avalanche paths could serve as an important outside carbon source for near and distant aquatic ecosystems.

The uncertainties in the continuous supply of fossil fuels from the crisis-ridden oil-rich region of the world is fast shifting focus on the need to utilize cellulosic biomass and develop more efficient technologies for its conversion to fuels and chemicals. One such technology is the rapid degradation of cellulose in supercritical water without the need for an enzyme or inorganic catalyst such as acid. This project focused on the study of reaction kinetics of cellulose hydrolysis in subcritical and supercritical water. Cellulose reactions at hydrothermal conditions can proceed via the homogeneous route involving dissolution and hydrolysis or the heterogeneous path of surface hydrolysis. The work is divided into three main parts. First, the detailed kinetic analysis of cellulose reactions in micro- and tubular reactors was conducted. Reaction kinetics models were applied, and kinetics parameters at both subcritical and supercritical conditions were evaluated. The second major task was the evaluation of yields of water soluble hydrolysates obtained from the hydrolysis of cellulose and starch in hydrothermal reactors. Lastly, changes in molecular weight distribution due to hydrothermolytic degradation of cellulose were investigated. These changes were also simulated based on different modes of scission, and the pattern generated from simulation was compared with the distribution pattern from experiments. For a better understanding of the reaction kinetics of cellulose in subcritical and supercritical water, a series of reactions was conducted in the microreactor. Hydrolysis of cellulose was performed at subcritical temperatures ranging from 270 to 340 °C (ô = 0.40-0.88 s). For the dissolution of cellulose, the reaction was conducted at supercritical temperatures ranging from 375 to 395 °C (ô = 0.27 - 0.44 s). The operating pressure for the reactions at both subcritical and supercritical conditions was 5000 psig. The results show that the rate-limiting step in converting cellulose to fermentable sugars in subcritical and supercritical water differs because of the difference in their activation energies. Cellulose and starch were both hydrolyzed in micro- and tubular reactors and at subcritical and supercritical conditions. Due to the difficulty involved in generating an aqueous based dissolved cellulose and having it reacted in subcritical water, dissolved starch was used instead. Better yield of water soluble hydrolysates, especially fermentable sugars, were observed from the hydrolysis of cellulose and dissolved starch in subcritical water than at supercritical conditions. The concluding phase of this project focuses on establishing the mode of scission of cellulose chains in the hydrothermal reactor. This was achieved by using the simulated degradation pattern generated based on different scission modes to fingerprint the degradation pattern obtained from experiment.

Research was conducted using algal biomass obtained from the surface of a secondary clarifier at Bridge City Wastewater Treatment Plant and subsequently sent through an electrochemical (EC) batch reactor at various concentrations. The first objective was to achieve maximum cell wall destruction electrochemically using the EC batch reactor and determine the optimal detention time and voltage/current relationship at which this occurred. The second objective was to subject two algal mediums to anaerobic digestion: the algal medium without electrochemical disinfection and the algal medium after disinfection. Every three days, for 12 days, total solids were measured from each apparatus to determine if cell destruction increased, decreased or did not change the consumption rate of algae by anaerobic bacteria. The consumption rate of algae is directly proportional to the production of methane, which can be used as a source of biofuel.

Reports indicate that the worldwide energy consumption and fossil fuel energy production level will have an opposite trend in the coming two decades. The former will continue to increase while the later will decrease. Therefore, additional sources of energy need to be developed. Field pennycress (Thlaspi, arvense L.) has been found to be an ideal source of energy because it has prolific yield and has no value as food. We demonstrated conventional and catalytic fast pyrolysis of whole pennycress biomass in a fluidized bed reactor. Characterization studies on field pennycress showed that the biomass had a potential to be converted to energy-rich bio-fuel. Thermogravimetric and kinetic study on field pennycress provided vital information on the degradation behavior of the feedstock. A parametric study was conducted on conventional rapid pyrolysis by using the effects model. The optimum experimental condition that gave maximum liquid yield was found to be at a temperature of 500 °C and a gas flow rate of 24 l/min. The catalysts used for catalytic fast pyrolysis were HZSM-5, a commercial catalyst, and red mud, an alumina industry waste material. The liquid products obtained from pennycress were found to have better qualities compared to a typical lignocellulosic feedstocks pyrolysis bio-oil. The bio-oil from the red mud catalyzed experiment had almost neutral pH of 6.5 and the pH in the case of HZSM-5 was 5.7. In comparison to bio-oil from conventional rapid pyrolysis, HZSM-5 and red mud reduced the viscosity of the bio-oil by 3 and 5 times, respectively. However, red mud was only found to be effective in improving the higher heating value (HHV) of the bio-oil from 33.18 MJ/kg (dry basis) in conventional pyrolysis to 35.7 MJ/Kg (dry basis). The HHV of HZSM-5 catalyzed bio-oil was 33.63 MJ/kg. The composition of non-condensable gases and the chemical makeup of the bio-oil from the two catalysts were different, suggesting that the reaction pathways could be different. HZSM-5 had higher selectivity for aromatics whereas red mud produced longer aliphatic chains. The bio-oil obtained from red mud catalytic pyrolysis of field pennycress is a promising alternative energy source that could replace petroleum fuels after some upgrading.

Fluidization characteristics and co-gasification of pulverized sub-bituminous coal, hybrid poplar wood, corn stover, switchgrass, and their mixtures were investigated. Co-gasification studies were performed over temperature range from 700°C to 900°C in different media (N2, CO2, steam) using a bubbling fluidized bed reactor. In fluidization experiments, pressure drop (ΔP) observed for coal-biomass mixtures was higher than those of single coal and biomass bed materials in the complete fluidization regime. There was no systematic trend observed for minimum fluidization velocity (Umf) with increasing biomass content. However, porosity at minimum fluidization (εmf) increased with increasing biomass content. Channeling effects were observed in biomass bed materials and coal bed with 40 wt.% and 50 wt.% biomass content at low gas flowrates. The effect of coal pressure overshoot reduced with increasing biomass content. Co-gasification of coal and corn stover mixtures showed minor interactions. Synergetic effects were observed with 10 wt.% corn stover. Coal mixed with corn stover formed agglomerates during co-gasification experiments and the effect was severe with increase in corn stover content and at 900°C. Syngas (H2 + CO) concentrations obtained using CO2 as cogasification medium were higher (~78 vol.% at 700°C, ~87 vol.% at 800°C, ~93 vol.% at 900°C) than those obtained with N2 medium (~60 vol.% at 700°C, ~65 vol.% at 800°C, ~75 vol.% at 900°C). Experiments involving co-gasification of coal with poplar showed no synergetic effects. Experimental yields were identical to predicted yield. However, synergetic effects were observed on H2 production when steam was used as the co-gasification medium. Additionally, the presence of steam increased H2/CO ratio up to 2.5 with 10 wt.% hybrid poplar content. Overall, char and tar yields decreased with increasing temperature and increasing biomass content, which led to increase in product gas.