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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Energy efficient storage of biomass at Vattenfall heat and power plant

Eriksson, Anders January 2011 (has links)
Storage of biomass is often associated with problems such as heat development, drymatter losses and reduction of fuel quality. The rise in temperature can potentiallycause a risk of self-ignition in the fuel storage. Moreover, emissions from storage pilescan cause health problems in the surrounding. The dry matter losses and reduction offuel quality can have economical effects. The aim of this thesis project is to developguidelines on how to store large amount of biomass at Vattenfalls heat and powerplants in an optimal way. Storage trials at Idbäckens CHP were done in order to studythe effect of storage on fuel quality, dry matter losses and temperature development.Two storage trials were performed over six weeks with waste wood chips and stemwood chips stored in about 4.5 m high outdoor piles. A trial over four days in whichwaste wood chips was placed on a heated surface was evaluated. A study to test thepossibility of using waste heat to dry waste wood chips was performed.Small but not negligible dry matter losses were observed in both of the piles of storedmaterial. The largest weekly losses were found during the first week of storage and adeclining behavior could thereafter be seen. The accumulated losses during six weeksof storage were 2.0 % and 1.7 % respectively, for waste wood and stem wood. Storageduring six weeks of waste wood and newly chipped stem wood did not cause anymajor deterioration of the fuel quality as such, beside the substance losses.No drying effect could be seen in the heated surface trial. The surface became warm,about 50°C, but it was not sufficient to dry the chips. The conclusion is that it is notpossible to dry large amount of chips on a heated surface with the design used hereand during four days.The overall conclusion is that in order to minimize the dry matter losses the materialshould be handled according to the LIFO (last in first out) principle. Wheneverpossible, try to purchase fuel that has been stored for a while since the more easilydegraded compounds has already been degraded through microbial activity. There is apossibility that the largest losses has already occurred. Furthermore, try also tocomminute the material (reduce the particle size) at the plant and as close in time tocombustion as possible.
2

Silagem de cana-de-açúcar tratada com aditivos químicos e microbianos: composição química e desempenho de vacas em lactação / Silage cane sugar treated with chemical additives and microbiological and performance of dairy cows with silages with additives

Cardoso, Lucas Ladeira 10 December 2013 (has links)
Made available in DSpace on 2015-03-26T13:55:23Z (GMT). No. of bitstreams: 1 texto completo.pdf: 801697 bytes, checksum: 32cbf2924b781d449fc5d6ed4f0df16d (MD5) Previous issue date: 2013-12-10 / This study was conducted based on two experiments. The first experiment was conducted to evaluate the chemical composition, the population of microorganisms, fermentation pattern and dry matter recovery of the following treatments: 1- Silage cane sugar; 2- Silage cane sugar with Lactobacillus buchneri, 3- Silage cane sugar with Lactobacillus plantarum and Pediococcus pentosaceus; 4- Silage cane sugar with Propionibacterium acidipropionici and Lactobacillus plantarum; 5- Silage cane sugar with 0.5% lime (CaO); 6- Silage cane sugar with 1.0% lime (CaO); 7- Silage cane sugar with 0.5% urea, 8- Silage cane sugar with 1.0% urea. We used completely randomized design with eight treatments and four replications, totaling 32 experimental units. The sugar cane was chopped and ensiled in 20 kg buckets containing Bunsen valves, open 180 days after ensiling. It was found that the sugar cane treated with urea markedly increased the protein levels and reduced levels of NIDA in silage, however, the concentration of nitrogen ammonia were also increased. The other additives provided no beneficial effects on silage composition, except the lime 0.5%, which reduced the NDF. The 0.5% lime produced higher lactic acid in silage. None of the additives was effective in increasing the population of lactic acid bacteria and decrease the population of yeast, like, did not benefit the recovery of dry matter or organic acid profile in relation to silage cane sugar without additives. The addition of 1% lime increased the yields of propionic acid and butyric acid. The inoculation Lactobacillus plantarum and Propionibacterium acidipropionici increased the ethanol content. Based on these results, it was observed that the silage is showed adequate fermentation profile, low population of yeast and high concentrations of ethanol and dry matter recovery. In experiment 2 was to evaluate the intake, digestibility, concentration of urea in blood plasma, the excretion of urea in urine, microbial efficiency, the average daily weight gain, yield and composition of milk from Holstein cows fed sugar cane sugar fresh, corn silage and cane sugar silages treated or not with microbial inoculants. The diets contained the following bulky: Corn silage, Sugarcane fresh; Silage cane sugar; Silage cane sugar with Lactobacillus buchneri and Silage of cane sugar with Lactobacillus plantarum and Pediococcus pentosaceus. Were used fifteen Holstein cows, allocated to individual pens and arranged in randomized block design, adopting milk production as factor of local control with three replications. Isonitrogenous diets were formulated to meet the requirements of lactating cows to produce 27 kg/day, whereas consumption was ad libitum and calculated to allow plenty of 10%. Means were compared by Tukey test at 5 % probability , using the SAS program. It was found that the intake of DM , OM, NDF and NFC did not differ (P>0.05). The CP intake was higher (P>0.05) for diets containing silages cane sugar, the TDN intake was higher (P>0.05) in the diet based on corn silage. The diet with corn silage had a higher value (P>0.05) digestibility of DM and OM compared to diets with silage cane sugar. The digestibility of crude protein (CP) did not differ (P>0.05) between diets. The digestibility of NDF in the diet based on corn silage was higher (P<0.05) than the other diets and silage cane sugar with Lactobacillus buchneri submitted the lowest. Among the diets had a lower (P<0.05) digestibility of NFC for diets containing cane sugar, compared to corn silage, being higher for silage cane sugar with Lactobacillus plantarum and Pediococcus pentosaceus. With respect to production parameters, no differences (P<0.05) were observed between diets for milk production, milk production corrected to 4% fat, milk fat, milk lactose and total solids, and found that there was less milk production (P <0.05) for treatment SC in relation to others, and higher crude protein content in milk (P<0.05) for the diet with cane sugar and less fresh content for silage diet with cane sugar treated with Lactobacillus plantarum and Pediococcus pentosaceus. There was difference between diets (P<0.05) concentrations of blood urea nitrogen (BUN) , and the diet of silage cane sugar made superior value to the other diets , while the cane sugar was detected in natura lower value compared to others. With respect to nitrogen urea urine (NUU) and microbial efficiency (EFMIC), it was found not to have been no difference between diets (P>0.05). The average daily gain (ADG) did not differ (P>0.05) between diets. It was concluded that diets with 60% concentrate added to sugar cane silage may allow cows to withstand average production of 25.8 kg / day of milk, similarly to other bulky sources traditionally used as silage corn and sugar cane fresh. / Foram conduzidos dois experimentos para avaliação de silagens de cana-de-açúcar. O experimento 1 foi realizado objetivando avaliar a composição química, a população de microrganismos, o perfil fermentativo e a recuperação de matéria seca. Os tratamentos utilizados foram: Silagem de cana-de-açúcar (SCA); Silagem de cana-de-açúcar com Lactobacillus buchneri (SCALB); Silagem de cana-de-açúcar com Lactobacillus plantarum e Pediococcus pentosaceus (SCALPPP); Silagem de cana-de-açúcar com Propionibacterium acidipropionici e Lactobacillus plantarum (SCAPALP); Silagem de cana-de-açúcar com 0,5% de cal (SCACaO0,5); Silagem de cana-de-açúcar com 1,0% de cal (SCACaO1,0); Silagem de cana-de-açúcar com 0,5% de ureia (SCAU0,5); Silagem de cana-de-açúcar com 1,0% de ureia (SCAU1,0). Foi utilizado o delineamento inteiramente casualizado, com oito tratamentos e quatro repetições, totalizando 32 unidades experimentais. A cana-de-açúcar foi picada e ensilada em baldes de 20 kg, contendo válvulas de Bunsen, abertos 180 dias após a ensilagem. Verificou-se que a cana-de-açúcar tratada com ureia aumentou acentuadamente os teores protéicos e reduziu os teores de NIDA na silagem, entretanto, os teores de nitrogênio amoniacal também foram incrementados. Os demais aditivos não proporcionaram efeitos benéficos na composição da silagem, exceto a cal a 0,5%, que reduziu o teor de FDN. A cal a 0,5% proporcionou maior produção de ácido lático no material ensilado. Nenhum dos aditivos foi eficaz em aumentar a população de bactérias ácido láticas ou diminuir a população de leveduras, assim como, não beneficiaram a recuperação de matéria seca nem o perfil de ácidos orgânicos em relação à silagem de cana-de-açúcar não aditivada. A adição de cal a 1% aumentou as produções de ácido propiônico e butírico. A inoculação com Propionibacterium acidipropionici e Lactobacillus plantarum aumentou o teor de etanol. Com base nos resultados obtidos, observou-se que as silagens estudadas apresentaram adequado perfil de fermentação, baixa população de leveduras e concentração de etanol e alta recuperação de matéria seca No experimento 2, avaliou-se o consumo, a digestibilidade, a concentração da ureia no plasma sanguíneo, a excreção de ureia na urina, a eficiência microbiana, o ganho de peso médio diário, a produção e composição do leite de vacas da raça Holandês alimentadas com cana-de-açúcar in natura, silagem de milho e silagem de cana-de- açúcar tratada ou não com inoculantes microbianos. As dietas utilizadas continham os seguintes volumosos: Silagem de milho (SM); Cana-de-açúcar in natura (CIN); Silagem de cana-de-açúcar (SCA); Silagem de cana-de-açúcar com Lactobacillus buchneri (SCALB) e Silagem de cana-de-açúcar com Lactobacillus plantarum e Pediococcus pentosaceus (SCALPPP). Foram utilizadas quinze vacas da raça Holandês, alocadas em baias individuais e dispostas no delineamento em blocos casualizados, adotando-se a produção de leite como fator de controle local, com três repetições. As dietas isonitrogenadas foram formuladas para atender as exigências das vacas em lactação, para produção de 27 kg/dia, sendo que o consumo foi ad libitum e calculado de forma a permitir sobra de 10%. As médias foram comparadas pelo teste Tukey, a 5% de probabilidade, utilizando-se o programa SAS. Verificou-se que os consumos de MS, MO, FDN e CNF, CMOD não diferiram entre si (P>0,05). O consumo de PB foi maior (P>0,05) para as dietas contendo silagens de cana-de-açúcar; o consumo de NDT foi maior (P>0,05) na dieta à base de silagem de milho. A dieta com silagem de milho apresentou valor mais elevado (P>0,05) de digestibilidade da MS e MO, em comparação às dietas com silagens de cana-de-açúcar. A digestibilidade da proteína bruta (PB) não apresentou diferenças (P>0,05) entre as dietas. A digestibilidade da FDNcp na dieta à base de silagem de milho foi superior (P<0,05) à das demais dietas, tendo a silagem de cana-de-açúcar com Lactobacillus buchneri apresentado o menor valor. Entre as dietas, observou-se menor (P<0,05) digestibilidade dos CNF para as dietas contendo cana-de-açúcar, em relação à de silagem de milho, sendo mais alta para silagem de cana-de-açúcar com Lactobacillus plantarum e Pediococcus pentosaceus. Com relação aos parâmetros produtivos, não foram observadas diferenças (P<0,05) entre as dietas, produção de leite corrigida para 4% de gordura, gordura do leite, lactose do leite e extrato seco total, sendo constatado que houve menor produção de leite (P<0,05) para o tratamento SC em relação aos demais e maior teor de proteína bruta no leite (P<0,05) para a dieta com cana-de-açúcar in natura e menor teor para dieta com silagem de cana-de- açúcar tratada com Lactobacillus plantarum e Pediococcus pentosaceus. Verificou-se diferença entre as dietas (P<0,05) para concentração de nitrogênio ureico do plasma (NUP), tendo a dieta à base de silagem de cana-de-açúcar apresentado valor superior às demais dietas, enquanto na cana-de-açúcar in natura foi detectado menor valor em relação aos outros. Com relação ao nitrogênio ureico da urina (NUU) e eficiência microbiana (EFMIC), constatou-se não ter ocorrido diferença entre as dietas (P>0,05). O ganho médio diário (GMD) não apresentou diferença (P>0,05) entre as dietas. Concluiu-se que dietas com 60% de concentrado adicionado à silagem de cana-de- açúcar podem permitir às vacas suportarem produção média de 25,8 kg/dia de leite, similarmente a outras fontes volumosas tradicionalmente usadas como a silagem de milho e a cana-de-açúcar in natura.

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