Biomass is one of the renewable and non-conventional energy sources and it includes municipal solid wastes and animal wastes in addition to agricultural residue. Concentrated animal feeding operations produce large quantities of cattle biomass which might result in land and water pollution if left untreated. Different methods are employed to extract the available energy from the cattle biomass (CB) which includes co-firing and gasification. There are two types of CB: Feedlot biomass (FB), animal waste from feedlots and dairy biomass (DB), animal waste from dairy farms. Experiments were performed in the part on gasification of both FB and DB. Earlier studies on gasification of DB with different steam-fuel ratios resulted in increased production of hydrogen. In the present study, dairy biomass was gasified in a medium with enriched oxygen percentage varying from 24% to 28%. The effect of enriched air mixture, equivalence ratio and steam-fuel ratio on the performance of gasifier was studied. Limited studies were done using a mixture of carbon dioxide and oxygen as the gasification medium and also a methodology was developed to determine the gasification efficiency based on mass and heat contents of gas. The results show that the peak temperature within the bed increases with increase in oxygen concentration in the gasification medium. Also carbon dioxide concentration in the mixture increases with corresponding decrease in carbon monoxide with increase in oxygen concentration of the incoming gasification medium. The peak temperature increased from 988°C to 1192°C as the oxygen concentration increased from 21% to 28% at ER=2.1. The upper limit on oxygen concentration is limited to 28% due to high peak temperature and resulting ash agglomeration. Higher heating value (HHV) of the gases decreases with increase in equivalence ratio. The gases produced using carbon dioxide and oxygen mixture had a higher HHV when compared to that of air and enriched air gasification. Typically the HHV of the gases increased from 2219 kJ/m³ to 3479 kJ/m³ when carbon dioxide and oxygen mixture is used for gasification instead of air at ER=4.2 in the absence of steam.

Orientador: Saulo Philipe Sebastião Guerra / Resumo: Este trabalho teve como objetivo avaliar o comportamento dos briquetes durante a queima, considerando a possibilidade de se aprimorar o índice de combustão de briquetes de biomassa (aqui denominado ICOMa) com o uso de um aplicativo de computador, de forma que esta nova proposta fosse mais sensível às variações dos dados que o ICOM (já existente na literatura), bem como determinar sua taxa de perda de massa em função do tempo de queima. Com esta nova proposta, também era esperado que se percebesse uma correlação entre o ICOMa e o poder calorífico superior da biomassa ensaiada, possibilitando estimar esta grandeza, ainda que de forma aproximada, sem o uso de uma bomba calorimétrica. A fabricação do dispositivo para obtenção do ICOMa foi baseada em trabalhos prévios obtidos na literatura, usando uma balança com porta de comunicação em protocolo RS 232, um termopar tipo K para medição da temperatura e um dispositivo para aquisição automática dos dados, feita por um aplicativo computacional também desenvolvido neste trabalho. Os briquetes usados nos ensaios foram de casca de algodão, toco de eucalipto, bagaço de cana-de-açúcar e madeira de pinus, e foram produzidos especificamente para a determinação do ICOMa. O aplicativo atendeu às necessidades do ensaio para obtenção das variáveis relacionadas aos índices de combustão. O ICOMa foi mais sensível que o ICOM na observação da relação entre consumo de massa e geração de calor, e permitiu observar diferenças estatisticamente signific... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work aimed to evaluate the behavior of briquettes during burning, considering the possibility of improving the combustion index of biomass briquettes (here called ICOMa) using a software, so that this new proposal to be more sensitive to data variations than ICOM (already existing in the literature), as well as to determine its mass loss rate as a function of burning time. It was also expected with this new proposal, that a correlation between the ICOMa and the higher heating value of the tested biomass could be perceived, making it possible to estimate this magnitude, albeit approximately, without the use of a bomb calorimeter. The manufacture of the device for obtaining the ICOMa was based on previous work obtained in the literature, using a RS 232 communication port scale, a type K thermocouple for temperature measurement, and a device for automatic data acquisition by a computational application, this one developed in this work. The briquettes used in the tests were cotton bark, eucalyptus stump, sugarcane bagasse, and pinewood, and produced specially for the determination of ICOMa. The computational application met the needs of the test to obtain the variables related to the combustion indexes. The ICOMa was more sensitive than the ICOM in observing the relationship between the mass consumption and heat generation, and show a statistical difference between different temperature curves of the materials, unlike the ICOM. The biggest ICOMa found was 0.97 K.h.g-1, and t... (Complete abstract click electronic access below) / Mestre

Growing minority cereal crops, including spelt wheat, einkorn wheat and emmer wheat, has seen significant development in recent years, mainly due to the development of organic farming. In the processing of these cereals, the amount of waste material in the form of plows, chaff and spindles fragments, which account for 23-35% of the gross yield, can be used as a material for energy production through direct combustion. In this respect, the higher heating value (Qsr) and the lower heating value (Qu) of spelt wheat was achieved. Spelt wheat also produced the highest gross yield (26,41 GJ ha-1) and the highest amount of waste material (33,23 %).

The thesis is focused on problems of thermal treatment of sludge from wastewater treatment plants. The main objective is to establish a formula for calculating higher heating value (HHV) and lower heating value (LHV) of sludge based on its chemical analysis. The work is divided into two main parts: The theoretical part deals with the characteristics of sludge, thermal treatment of sludge, it isn´t omitted higher heating value and lower heating value. The main topic of a practical part is formulation of eguations for HHV and LHV calculation. Chemical analysis of sludge samples were supplied by TÜV NORD Czech s.r.o., together with the values of HHV and LHV. The calculations were verified by the program MINITAB.

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