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Condições que potencializam a propagação de incêndios florestais e a emissão de poluentes gasosos para a atmosfera / Conditions that enhance the spread of forest fires and the gases emissions to atmosphereAmaral, Simone Simões [UNESP] 12 April 2017 (has links)
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Previous issue date: 2017-04-12 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Apesar das novas tecnologias de gerenciamento e combate aos incêndios, o fogo em florestas ainda ocorre em grande escala, causando danos ao meio ambiente e à sociedade. Os danos causados pelo fogo são dependentes de fatores como combustível, clima e topografia do terreno. Para minimização e controle dos efeitos causados pelo fogo é importante o estudo de tais fatores. Assim, o objetivo deste trabalho foi analisar a condição que potencializa a propagação do fogo e a emissão de poluentes gasosos. O estudo da condição que potencializa o fogo e suas emissões foi realizado para biomassas de florestas plantadas. Os principais fatores, que afetam o fogo e suas emissões, foram avaliados através de experimentos de laboratório. Os fatores de controle avaliados foram: espécie, percentual de liteira, carga de combustível, irradiância solar, umidade relativa, velocidade do vento e inclinação do terreno. Estes experimentos foram planejados e analisados utilizando a matriz L18 da metodologia de Taguchi. O dispositivo de queima foi adaptado, para que o estudo pudesse ser realizado. As emissões também foram quantificadas para floresta nativa (biomassa da Amazônia), com experimentos conduzidos em campo e em laboratório. Para os níveis dos fatores estabelecidos, em laboratório, a condição encontrada que potencializou a propagação do fogo e a emissão de poluentes gasosos foi a queima de Eucalyptus sp., com aproximadamente 30 % de liteira, carga de 2,5 kg de combustível, nível mínimo de umidade relativa (40 %), velocidade do vento de 3,5 m/s e inclinação do terreno de 30°. A máxima irradiância (1kW/m2) potencializou as emissões gasosas, cujos valores de fator de emissão foram de 1.495±62 g/kg para CO2, 71,52±4,33 g/kg para CO, 1,96±0,78 g/kg para NO e 14,75±3,55 g/kg para UHC. Experimentos conduzidos com a irradiância no nível 1 potencializaram a propagação do fogo. Quando comparados os resultados de queima de biomassa da Amazônia, a queima em campo apresentou valores mais elevados das emissões por hectare, para os compostos parcialmente oxidados. / Despite the new technologies of management and fire fighting, fire in forests still occurs on a large scale, causing damage to the environment and society. The damages caused by the fire are dependent on factors such as fuel, weather, and topography of the land. To minimize and control the effects caused by fire is important the study of such factors. Thus, the objective of this work was to analyze the condition that enhances the spread of fire and the emission of gaseous pollutants. The study of the condition that enhances the fire and their emissions was conducted for biomasses of planted forests. The main factors, which affect the fire, were evaluated through laboratory experiments. The control factors evaluated were: specie, percentage of litter, fuel load, irradiance, relative humidity, wind speed and inclination. These experiments were designed and analyzed using the matrix L18 of Taguchi methodology. The burning device was adapted, so that the study could be performed. The emissions were also quantified to native forest (Amazon biomass), with experiments conducted in the field and in the laboratory. For the levels of the established factors, the condition found that enhanced the spread of fire and the emission of gaseous pollutants was: Eucalyptus sp. burning, with approximately 30% litter, 2.5 kg of fuel load, minimum relative humidity (40%), wind velocity of 3.5 m/s and inclination of 30°. The maximum irradiance (1kW/m2) potentiated the gaseous emissions, whose emission factor values were 1,495 ± 62 g/kg for CO2, 71.52 ± 4.33 g/kg for CO, 1.96 ± 0.78 g/kg for NO and 14.75 ± 3.55 g/kg for UHC. Experiments conducted with irradiance at level 1 enhanced the spread of fire. When the results of the Amazon biomass burning were compared, field burning presented higher emissions per hectare, for partially oxidized compounds. / FAPESP: 2013/21231-0
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Caracterização e avaliação do potencial energético dos resíduos florestais da indústria de papel e celulose : Characterization and energy potential assessment of the forestry residues from the paper and pulp industry / Characterization and energy potential assessment of the forestry residues from the paper and pulp industryPena Vergara, Gabriel, 1986- 24 August 2018 (has links)
Orientador: Waldir Antonio Bizzo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-24T19:52:20Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014 / Resumo: A indústria de papel e celulose é a principal consumidora de biomassa como combustível e como matéria-prima, gerando resíduos de biomassa, os quais representam uma grande quantidade de energia disponível. A produção de papel e celulose necessita de grandes quantidades de energia tanto mecânica quanto térmica, a qual usualmente é produzida através da queima de biomassa. Além dos resíduos gerados na própria indústria, a cadeia de produção de papel e celulose envolve uma importante atividade florestal, da qual é aproveitada a madeira e geralmente deixando no campo resíduos de biomassa, os quais representam entre 15 e 25% da massa seca da árvore. Este trabalho de pesquisa enfoca-se na caracterização como combustível dos resíduos sólidos gerados no campo (folhas, cascas, galhos e pontas) e na produção de papel e celulose (finos, cascas, cavacos e lodo orgânico). Também é estimado o potencial de geração de energia elétrica pela combustão dos resíduos de biomassa através do ciclo Rankine. A caracterização baseia-se em uma serie de análises pelos quais é estudada a degradação térmica (análises térmicas - TGA e DSC), e determinada a composição elementar, imediata e estrutural, poder calorífico e massa específica. São caracterizadas também as cinzas determinando sua composição elementar. O material empregado é proveniente do gênero eucalipto espécie Urograndis. As biomassas estudadas apresentam-se propriadas para ser empregadas como combustível em fornalhas industriais. Os resíduos florestais e os rejeitos de madeira da fábrica têm algumas desvantagens em relação a outras biomassas como a madeira. Estas desvantagens são o teor de cinzas, principalmente nas folhas e casca (entre 3 e 5% b.s.), a elevada umidade (acima de 50% b.u.) e sua difícil manipulação. Porém, essas biomassas melhoram suas propriedades com o passar do tempo deste material no campo, diminuindo sua umidade e reduzindo o teor de cinzas, cloro e potássio. A combustão do lodo pode ser energeticamente deficiente devido ao seu elevado teor de umidade e baixo poder calorífico. O potencial de geração de energia elétrica é elevado, desde que a produtividade dos resíduos é grande e seu poder calorífico similar à madeira original. Conclui-se que sem considerar as questões de logística, os resíduos de biomassas em questão têm grande potencial energético ainda não aproveitado / Abstract: The pulp and paper industry is the major consumer of biomass fuels and feedstock, as a result it generates biomass waste, which represents a great amount of heat energy available. The production of pulp and paper requires large quantities of mechanical and heat energy. This energy is usually supplied by burning biomass in boilers, generating steam that is used as heat source and to generate electricity. Besides the waste generated in the industry, the paper and pulp production chain involves an important forestry activity, in which generally the wood is taken and the biomass residues are leaved at the forest. That represents between 15 and 25% of the tree dry mass. This research focuses on the solid residues generated at the forest (bark, branches, tips and leaves) as well as in the production of pulp and paper (fines, bark, organic sludge and chips), characterizing them as fuel. The objective is also estimate the electric potential of the combustion of biomass residues through the steam Rankine cycle. The characterization is based on a range of analysis, studding the thermal degradation (thermal analysis - TG and DSC), and determining the elemental and immediate composition, heating value, density and chemical structure. Also, the ash elemental composition is established. The material used is taken from the Eucalyptus genus Urograndis species. The studied biomass is suitable to be used as fuel in industrial furnaces. The forestry residues and factory wood rejects have some disadvantages regarding to others biomass like wood. The main disadvantages are the ash content, especially in the leaves and bark (between 3 and 5\% d.b.), high moisture (above 50% w.b.) and its handling difficult. However, the chemistry properties of the biomass improve as it remains at the forest for a period of time, decreasing its moisture and reducing the ash, chlorine and potassium contents. The organic sludge combustion could be energy deficient due to its high moisture and its low heating value. The electric potential is high, since the productivity of waste is large and its heating value is similar to the original wood. We conclude that without considering the logistics issues, the biomass waste has great energy potential, generally untapped / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica
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Modeling of Wet Scrubber with Heat Recovery in Biomass Combustion PlantsJohansson, Wilhelm January 2020 (has links)
During combustion of biomass, particulate matter is emitted, which has severe health impacts on humans. The company ITK Envifront has developed a scrubber technology that cleans the flue gas while also recovering the flue gas energy, increasing the efficiency of the combustion plant. In this thesis, a simulation model was built in MATLAB according to the Finite Element Method. Validation of the model against 3 different facilities showed reasonable accuracy with a tendency to overestimate the scrubber heat recovery and a mean prediction deviation of approximately 7 %. The model was then used to make suggestions for process optimization. An increase of funnel height, and number of spray nozzles could increase the scrubbers heat recovery with up to 7 % and 8 %, respectively. Addition of moisture to the flue gas through evaporation of water droplets had the potential to increase scrubber efficiency with 10 %, and usage of the highest setting of the adjustable nozzle bank showed the potential to increase the efficiency with up to 5 % compared to the mid-setting. Furthermore, the process parameters of a scrubber with optimized running conditions, was compared to a scrubber with the current running conditions, through running of the developed model. The optimized running conditions showed an increase in scrubber efficiency with up to 14 %, resulting in an increase in scrubber heat recovery of approx. 90 kW at a boiler load of 3 MW. As a final conclusion, the developed model shows great potential to be used to as a toolbox to further investigate and optimize the scrubber design and operation. As a future work, it would be interesting to further model its performance regarding particle removal.
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Combustion characteristics of steam-exploded biomass pelletsPonce Valle, Maria Gabriela January 2011 (has links)
Currently pelletized woody biomass is widely used as a fuel in thermal applications toaccelerate the global transition to renewable energy. Fuel upgrade is one of the key factorsto improve energy conversion processes. Woody biomass can be fractionated into its mainconstituents by steam explosion. Steam-exploded biomass exhibits enhanced heating valueand improves pellet durability. Moreover, there is a significant deviation in thermochemicalbehavior of steam exploded (steam-treated) biomass with respect to the raw material duringpyrolysis. This thesis work concerned combustion characteristics of steam-exploded salix. The steamtreatedmaterial was pelletized and combusted under 21% of oxygen with varying thereactor temperature from 500 to 900°C to study the influence of both surrounding andpretreatment conditions during combustion process. The impact of different pretreatmentseverity factors (Ro) on burning behavior was evaluated: mild (205°C-6min, Ro=3.87),intermediate (205°C-12min, Ro=4.17) and severe (228°C-12min, Ro=4.84). Heterogeneousand homogenous ignition mechanisms were observed, which were dependent on the reactortemperature. The ignition time and devolatilization duration were observed independent onpretreatment severity near 900°C, and slightly influenced near 500°C. Enhanceddevolatilization rate was detected with the increment of Ro from 3.87 to 4.17, whilst themost severe pretreatment conditions (Ro=4.84) weakened biomass reactivity duringdevolatilization. Finally, char reactivity was lowered as a result of the increment ofpretreatment severity.
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The feasibility of producing and utilizing bioenergy in Linga Linga, Mozambique : Potential resources, conversion techniques and applications / Möjligheten att producera och utnyttja bioenergi i Linga Linga,Moçambique : Potentiella resurser, omvandlingsteknikeroch användningsområdenEbrahim, Mila, Lilja, Fanny January 2019 (has links)
The aim of the project was to investigate the possibility of producing and utilizing bioenergy from available local resources in the village Linga Linga, Mozambique. Suitable conversion techniques for producing and utilizing bioenergy were identified through a literature study. The investigated techniques were the concept of gasifier cookstoves, the method of producing charcoal from biomass and anaerobic digesters. Through observations and interviews in the village, available local resources suited for the conversion techniques were identified. In the field study, it was found that there is a surplus of solid biomass which led to the conclusion that a gasifier cookstove is suitable to implement. In order to analyze if a gasifier cookstove is suitable for the households, interviews were carried out in ten households in the village. Aprototype of a gasifier cookstove was built with local resources to determine if the technique can be applied. The prototype was tested and evaluated in order to analyze if it will contributeto a more efficient use of resources. One of the conclusions of the study was that a gasifier cookstove can be valuable for the households in several ways, but that cultural differences can make it hard to implement.
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Effects of fuel blends containing Croton oil, Butanol and Diesel on the performance and emissions of Diesel engines.Lujaji, Frank. January 2010 (has links)
M. Tech. Mechanical Engineering. / Evaluates the effects of blends (vegetable oil-Butanol (BU) alcohol-diesel) on fuel properties, engine performance, combustion, and emission characteristics. Fuel blends investigated were croton oil (CRO), Diesel (D2), 20% CRO-80% D2, 15% CRO-5% BU-80% D2 and 10% CRO-10% BU-80% D2.
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Energetické využití zemědělské biomasy spalováním / Energy use of agriculture biomass by combustionŠPAČEK, Zdeněk January 2014 (has links)
This thesis deals with combustion of lignocelluloses biomass with comparison to cellulose-lignin biomass and with appropriateness of different combustion technologies in the context of the impact on the environment. Furthermore, the thesis deals with content of the heating value in the individual fuels. The heating value capacity was measured experimentally in different kinds of biomass by method of dry distillation and these results were statistically evaluated and and discussed with the findings taken from literature. On the basis of literature data, differences have been discovered in lignocelluloses fuels in terms of calorific value and heating value, calorific values were in average from 15,3 MJ/kg to 16,8 MJ/kg and heating values were 17,5 18,1 MJ/kg. While in cellulose-lignin fuels these differences are not that big and are within values of 19,5 MJ/kg for heating value and an average calorific value is around 18,4 MJ/kg. Measuring of the content of tar and other residual fluid fractions in five the most commonly used bio-fuels from agricultural production (wheat straw, rape straw, hay, energy crops, digestate from biogas station). After statistical evaluation of data, it revealed the difference in content of tar between the wheat straw and digestate (P 0,05; on average 40,48 % for wheat straw and 29,58 % for digestate).
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Avaliação físico-química das cinzas dos resíduos da cultura da mandioca durante a formação de aglomerações com material inerte / Physical/chemical assessment of the ashes from residues of cassava harvest during the formation of agglomerations with inert materialMartinez Sarache, Handel Andres, 1986- 08 November 2014 (has links)
Orientador: Waldir Antonio Bizzo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-26T01:38:12Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014 / Resumo: A tecnologia do leito fluidizado é considerada uma das alternativas que oferece maior eficiência e flexibilidade para o aproveitamento energético de combustíveis sólidos. O material de leito geralmente usado é a areia devido aos seus baixos custos e facilidade de obtenção. Porém, o aproveitamento energético de resíduos agrícolas, que possuem alto teor de álcalis, em reatores de leito fluidizado apresenta um problema relacionado às interações entre o material do leito e as cinzas da biomassa. Este problema é caraterizado pela aglomeração do material contido no interior do leito, o que pode conduzir à perda do estado de fluidização ocasionando paradas não programadas do reator para troca do material. Entre os diversos mecanismos propostos para contra-arrestar a formação de aglomerações, durante a combustão de biomassa, o uso de matérias de leito de baixo conteúdo de sílica e a lavagem prévia da biomassa tornam-se alternativas economicamente viáveis. Através das técnicas de Análise Térmica Simultânea (TG/DTA) e Microscopia Eletrônica de Varredura (MEV) buscou-se avaliar a tendência das cinzas dos ramos grossos da planta de mandioca à formação de aglomerações, como consequência das interações físico-químicas quando estão misturadas com areia a altas temperaturas. Misturas das cinzas com alumina e com dolomita foram testadas a fim de comprovar que reduzem a formação de aglomerações. Também foi estudado o efeito da lavagem simples da biomassa com água. Os resultados obtidos mostraram que ao redor de 770 °C o potássio contido nas cinzas reagiu com a sílica da areia formando eutéticos de baixo ponto de fusão compostos pelo sistema K2O-SiO2, que se depositaram sobre os grãos de quartzo e aderiram as partículas de inerte ao redor, promovendo a formação de aglomerações. Aproximadamente a 900 °C aconteceu a difusão de Mg, Ca e Fe que reagiram com o material depositado formando uma camada adicional de recobrimento, composta pelos sistemas K2O-SiO2-MgO e/ou K2O-SiO2-CaO-Fe2O3, que fortaleceu as uniões formadas entre as partículas de areia aglomeradas. Estes resultados concordam com os mecanismos de formação de aglomerações propostos na literatura / Abstract: The fluidized bed technology is considered one of the alternatives that offer greater efficiency and flexibility for the energetic use of solid fuels. The bed material commonly used is silica sand due to its low cost and ease of production. However, the energetic use of agricultural residues in fluidized bed reactors, often present a problem related to the interactions between the bed material and biomass ashes, which generally have high alkali content. This problem is characterized by the agglomeration of the material contained within the bed, which can lead to defluidization and unscheduled shutdowns of the reactor to change the bed material. Among the different mechanisms proposed to counteract the formation of agglomerations during the biomass combustion, the use of alternative bed materials of low content of silica and water leaching of the biomass, become economically viable alternatives. Simultaneous Thermal Analysis (TG/DTA) and Scanning Electron Microscopy (SEM) techniques were used to evaluate the trends of the ashes produced from cassava branches to agglomerations, as a result of physicochemical interactions when mixed with sand at high temperatures. Different mixtures between ashes with alumina and with dolomite were tested in order to reduce the formation of agglomerations. The effect of leaching the biomass with water was also studied. The results showed that about 770°C, the potassium contained in the ashes reacted with the silica sand particles surface, forming low melting point eutectics governed by the K2O-SiO2 system, which were deposited and adhered to quartz particles around, promoting the formation of agglomerations. Around 900°C took place the diffusion of Mg, Ca and Fe which reacted with the deposited material, forming an additional coating layer composed of K2O-SiO2-MgO and/or K2O-SiO2-CaO-Fe2O3 systems, that strengthened the joints formed between the agglomerated sand particles. These results agreed with the agglomerations formation mechanisms, proposed in the literature / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica
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Záměna zdroje v lokální výtopně 2,5 MW / Change of heat source in a heating palnt 2.5 MWPikola, Jan January 2010 (has links)
The scope of this Master´s thesis is estimation of changing of heat source in a heating plant 2.5 MW. In the present heating plant burns natural gas, placing of the heating plant makes it possible development source of burning biomass. The scope of thesis is establish with regard to developed capital and operational costs, next effects to environment in scene of heat source, measuring and regulation of technological unit, determination of acceptable size of fuel depot and composition of fuel and ashes economy. The results of this Master´s thesis can be used as a basis about determination toward investment.
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Burnout, NO, and Flame Characterization from an Oxygen-Enriched Biomass FlameOwen, Steven Andrew 01 May 2015 (has links) (PDF)
Concern for the environment and a need for more efficient energy generation have sparked a growing interest throughout the world in renewable fuels. In order to reduce emissions that negatively contribute to global warming, especially CO2, enormous efforts are being invested in technologies to reduce our impact on the environment. Biomass is an option that is considered CO2 friendly due to the consumption of CO2 upon growth. Co-firing biomass with coal offers economic advantages because of reduced capital costs as well as other positive impacts, such as NOx and SOx emission reductions. However, due to the large average particle size of biomass, issues arise such as poor flame stability and poor carbon burnout. Larger particles can also result in longer flames and different heat transfer characteristics. Oxygen enrichment is being investigated as a possible solution to mitigate these issues and enable co-firing in existing facilities. An Air Liquide designed burner was used in this work to explore the impact of oxygen enrichment on biomass flame characteristics, emissions, and burnout. Multiple biomass fuels were used (medium hardwood, fine hardwood, and straw) in conjunction with multiple burner configurations and operating conditions. Exhaust ash samples and exhaust NO were collected for various operating conditions and burner configurations. All operating parameters including O2 addition, swirl, and O2 location could be used to reduce LOI but whenever LOI was reduced, NO increased producing an NO-LOI trade-off. Starting with high LOI, various parameters such as O2 addition and increased swirl could be used to reduce LOI with only small increases of NO. As O2 or swirl increased further, small decreases in LOI were obtained only with large increases in NO. This behavior was captured through NO-LOI trade-off curves where a given configuration or operating condition was deemed better when the curve was shifted toward the origin. Global enrichment or O2 addition to the secondary stream and O2 addition to the primary stream produced better trade-off results than center O¬2 injection. Straw produced NO-LOI trade-off curves just as the wood particles but the curve was shifted further from the origin, likely due to the higher nitrogen content of the straw. Flame characterization results showed that small amounts of O2 in the center improved flame attachment and stability while increasing flame temperature and pyrolysis rates.
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