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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.
141

Avaliação tecnológica da madeira de Pinus maximinoi visando sua utilização industrial na produção de celulose kraft / Technological evaluation of Pinus maximinoi wood for industrial use in kraft pulp production

Marina Ulian Coêlho 20 June 2017 (has links)
A baixa porcentagem de plantios com árvores do gênero Pinus no Brasil e a crescente demanda por polpa celulósica de fibra longa no país evidenciam a necessidade de estudos de espécies de pinus tropicais que se desenvolvam em regiões além do sul brasileiro. Os objetivos deste trabalho foram caracterizar tecnologicamente a madeira de Pinus maximinoi e avaliar o desempenho desta matéria-prima para produção de polpa celulósica, a partir do processo de polpação modificado do tipo Lo-Solids®. Utilizou-se como referência tecnológica a madeira de Pinus taeda, espécie mais empregada no país para produção de polpa celulósica de fibra longa. Foram analisadas 5 árvores de P. maximinoi e 5 árvores de P. taeda, com 14 anos de idade e plantadas nas mesmas condições edafoclimáticas. As madeiras das duas espécies foram caracterizadas tecnologicamente quanto a densidade básica da madeira, composição química e morfologia dos traqueídes. Posteriormente, foram realizados cozimentos de caracterização, utilizando-se o processo de polpação kraft convencional com diferentes níveis de cargas alcalinas, com o intuito de avaliar o desempenho da madeira de P. maximinoi frente ao processo de polpação e ajustar modelos matemáticos para estimar parâmetros de interesse . Foram obtidas polpas branqueáveis com número kappa = 28±5% a partir do processo de polpação modificado do tipo Lo-Solids®, com fator H 2295, sulfidez de 30% e relação licor madeira de 4L/kg. Os resultados de caracterização da madeira de P. maximinoi demonstraram que esta possui densidade básica equivalente a 0,417 g/cm3, teores de 64,49 % de holocelulose, 31,06% de lignina total, 4,45% de extrativos totais e 0,16% de cinzas e traqueídes com 4,19 mm de comprimento, 56,95 μm de largura, 44,11 μm de diâmetro de lúme e 6,42 μm de espessura da parede. Os resultados dos cozimentos Lo-Solids® mostraram que a madeira de P. maximinoi demandou álcali ativo de 24,4% (base NaOH) e resultou em polpas com rendimento depurado de 47,5%, teor de rejeitos de 0,43% e viscosidade de 713 cm3/g. O consumo específico da madeira de P. maximinoi foi de 5,868 m3/tsa e incremento médio anual em celulose de 6,575 tsa/ha/ano. O teor de sólidos gerados por tonelada de celulose produzida para a madeira de P. maximinoi foi de 1,451 t/tsa. Os resultados obtidos neste estudo permitem concluir que a madeira de P. maximinoi representa uma alternativa interessante para produção de polpa celulósica de fibra longa, tendo em vista que possui características tecnológicas muito semelhantes à madeira de P. taeda, além do menor consumo específico da madeira e maior incremento médio anual em celulose. / The low percentage of plantation of pine genus in Brazil and the growing demand for long fiber pulp demonstrates the necessity of studies with tropical pine species that develop in regions beyond the south of Brazil. The main objectives of this study were to characterize the wood of the specie Pinus maximinoi and to evaluate the performance of this material for pulp kraft production, using the modified pulping process Lo-Solids®. Pinus taeda wood was used as technologinal reference since it is the most used pine specie in Brazil for softwood pulp production. Samples from 5 Pinus maximinoi trees and 5 Pinus taeda trees were analysed both with 14 years old, planted in the same conditions. Both of the materials were technollogicaly characterized by wood basic density analysis, wood chemistry and tracheids morphology. After that, were realized characterization pulping processes, using the conventional kraft pulping process, with different alkali charges, in order to study the behavior of Pinus maximinoi wood throughout the process and ajust mathematical models to estimate parameters of interest. Then, it was produced bleached pulps with kappa number of 28±5% using the modified pulping process Lo-Solids®, with H factor 2295, 30% of sulfidity and liquor to wood ratio = 4L/kg. The results from the wood characterization shows that Pinus maximinoi wood has basic wood density equivalent to 0,417 g/cm3, 64,49% content of holocellulose, 31,06% content of total lignin, 4,45% content of total extractives and 0,16% content of ash; the tracheids morphology showed that the tracheids has lenght 4,19 mm, 56,95 μm of width, 44,11 μm of lumen width and 6,42 μm of wall thickness. The results of the Lo-Solids® pulping process showed that Pinus maximinoi wood has demanded alkali charge of 24,4% (NaOH) and resulted in pulps with screened yield of 47,5%, rejects contents of 0,43% and viscosity pulp of 713 cm3/g. The specific wood consumption was 5,868 m3/tsa and the IMACEL 6,575 tsa/ha/ano. The solids content generated per ton of cellulose was 1,451 t/tsa for Pinus maximinoi wood. The results obtained in this study showed that the Pinus maximinoi wood represents an interesting alternative for softwood pulp production given that the technological characteristics were very similar between the P. taeda wood, beyond the higher forestry production, the lower wood specific consumption observed and higher IMACEL.
142

Elaboration de matériaux bioactifs à partir de fibres lignocellulosiques / Development of bioactive materials from fibers lignocellulosic

Nzambe Ta Keki, Jean Kerim 21 December 2015 (has links)
Les contaminations des surfaces constituent un problème majeur de santé public rencontré dans plusieurs secteurs tels que les milieux hospitaliers et l’industrie alimentaire. Cette contamination consiste en l’adhésion de bactéries pathogènes ou opportunistes qui peuvent former des biofilms. Ces biofilms sont potentiellement des sources de développement et de prolifération des bactéries. Une voie efficace de lutte contre la contamination microbienne est l’élaboration de surfaces bactéricides visant à empêcher ou diminuer l’adhésion bactérienne. Basé sur le savoir-faire du laboratoire de Chimie des Substances Naturelles dans le domaine des polysaccharides, nous avons entrepris d’élaborer des supports antibactériens en fixant de manière covalente des molécules aux propriétés antibactériennes sur des fibres lignocellulosiques de pâte à papier (la pâte Kraft). Le lien triazole formé est stable vis-à-vis de l’hydrolyse acide ou basique, et subsiste dans des conditions oxydantes et réductrices. Nous avons choisi de nous intéresser dans un premier temps à la fixation de manière covalente d’un antibactérien commercial connu, le triclosan, sur des fibres lignocellulosiques de la pâte à papier ; puis dans une deuxième approche nous nous sommes orientés vers la fixation de porphyrines sur ces supports. Enfin dans une troisième approche, nous avons fixés des molécules aromatiques qui n’acquièrent leur potentiel antimicrobien qu’après greffage sur le support via le lien triazole. L’étude de l’effet antimicrobien des différents matériaux a montré pour une activité bactéricide du matériau Pâte Kraft-triclosan vis-à-vis notamment de trois souches fréquemment trouvées en milieu hospitalier: Pseudomonas aeruginosa, Bacillus cereus et Escherichia coli ; Dans le cas du greffage de photosensibilisateurs, seul le matériau pâte Kraft-Porphyrine neutre a permis une photoinactivation des souches après irradiation. / Surface contamination by pathogens constitutes a major public health problem encountered in many areas such as hospitals, environment and food industry. This contamination consists in the adhesion of pathogenic or opportunistic bacteria that can attach to a biotic or abiotic surface and lead to the formation of biofilm. An effective way to fight against microbial contamination is the development of antibacterial surfaces, in order to prevent or reduce bacterial adhesion. Based on the expertise of the Laboratoire de Chimie des Substances Naturelles in the field of polysaccharides, we have undertaken the development of antibacterial materials by grafting through covalent bonds molecules presenting antibacterial properties onto lignocellulosic fibers (in this case Kraft pulp fibers). Triazoles are resistant to acid and basic hydrolysis, reductive and oxidative conditions. This moiety is also relatively resistant to metabolic degradation and is not posing particular toxicity problems. The study of the antibacterial effect has shown a bactericidal activity of the triclosan-Kraft pulp sheet against three strains frequently found in hospitals: Pseudomonas aeruginosa, Bacillus cereus and Escherichia coli. In the case of grafting photosensitizers, only the neutral porphyrin-Kraft pulp sheet material displayed a strong photobactericidal activity after irradiation.
143

Entwicklung und Systemintegration einer Mikro-Wärme-Kraft-Kopplungsanlage für feste Biomasse

Krüger, Dennis 06 February 2020 (has links)
In dieser Arbeit wird eine entwickelte Mikro-Wärme-Kraft-Kopplungsanlage für die Nutzung fester Biomasse beschrieben und vermessen, welche hochflexibel in einem sehr kleinen Leistungsbereich von unter 1 kWel arbeitet. Die Anlage verfügt über einen Gegenstromfestbettvergaser, einen Verbrennungsmotor und einen Gleichstromgenerator. Als Brennstoff wird Holzkohle und als Vergasungsmittel Luft genutzt, der Betrieb erfolgt autotherm. Es werden die Machbarkeit, die systemrelevanten Parameter und das dynamische Verhalten der Anlage dargestellt. Aufbauend auf diesen Ergebnissen werden die technischen und rechtlichen Anforderungen bezüglich einer Integration in ein häusliches Umfeld betrachtet. Weiterhin wird eine ökonomische Betrachtung durchgeführt, um den anzustrebenden Pfad zur Weiterentwicklung zu identifzieren. Abschlieÿend wird mit Hilfe der gemessenen Daten gezeigt, wie eine Referenzanlage modelliert und notwendige Gleichungen zur Anlagensimulation gebildet werden, um einen dynamischen Betrieb hochaufgelöst darzustellen. / In this thesis a micro-cogeneration unit for the use of solid biomass is shown, which operates flexible in a very small power range of less than 1 kWel. The plant has a countercurrent fixed bed gasifier, an internal combustion engine and a DC generator. Charcoal is used as fuel and air as a gasification agent, the operation is autothermal. The feasibility, the system-relevant parameters and the dynamic behavior of the system are shown. Based on these results, the technical and legal requirements for integration into a home environment are considered. Furthermore, an economic analysis is carried out to identify the desired path to further development. Finally, with the help of the measured data it is shown how a reference plant is modeled and necessary equations for the plant simulation are formed in order to represent a dynamic operation in high resolution.
144

Fertilizante Natural: Agro Dust / Natural Fertilizer: Agro Dust

Avendaño Gil, Gianfranco Emilio, Bazán Durand, Daniel Antonio, Maza Fajardo, Rodrigo Alonso, Ochoa Bustamante, Juan Diego, Torres Paredes, Maria Elizabeth 27 November 2019 (has links)
El presente proyecto se basa en la producción y comercialización de fertilizante natural y biodegradable, que sirve como bio-estimulante para las plantas ornamentales, teniendo como valor adicional ser un retenedor de agua de riego durante 20-21 días aplicando una sola vez el producto. Elaborado a base de cáscara de naranja y palta, nuestro negocio va dirigido a habitantes de Lima Moderna correspondientes a los estilos de vida conservador, moderno y sofisticado que posean plantas y/o pequeños jardines pertenecientes a los niveles socioeconómicos (NSE) A, B y C, además de mostrar preocupación por el medio ambiente. El empaque del producto va a ser una bolsa de papel kraft biodegradable con una capacidad 250 gramos. Se realizó una total de entrevistas a 30 personas para validar la existencia del problema encontrado y el interés e intención de uso del producto de nuestros posibles clientes. Además, con fines de hacer este proyecto escalable para el rubro de la agricultura, se contactó a dos expertos en agronomía para validar el producto y algunos aspectos sobre la posible escalabilidad de este. El desarrollo del proyecto se encuentra dividido en dos puntos, los cuales son la validación del plan de negocio y desarrollo del plan de negocio. Para la ejecución del proyecto se requirió una inversión de 21,454 soles, obtenidos a base de capital propio de los accionistas, quienes estiman recuperar dicha inversión en el primer año de operación. La rentabilidad brindada a los accionistas es de 249% lo cual hace nuestro proyecto un negocio rentable. / The present project is based on the production and commercialization of natural and biodegradable fertilizer, which serves as a bio-stimulant for ornamental plants, with the additional value of being a water retainer for 20-21 days by applying the product once. Made with orange and avocado peel, our business is aimed at inhabitants of Modern Lima corresponding to conservative, modern and sophisticated lifestyles that have plants and / or small gardens belonging to socioeconomic levels (NSE) A, B and C, in addition to showing concern for the environment. The product packaging is going to be a biodegradable kraft paper bag with a capacity of 250 grams. A total of interviews were conducted with 30 people to validate the existence of the problem encountered and the interest and intention of using the product of our potential customers. In addition, in order to make this project scalable for the field of agriculture, two agronomy experts were contacted to validate the product and some aspects of its possible scalability. The development of the project is divided into two points, which are the validation of the business plan and development of the business plan. For the execution of the project, an investment of 21,454 soles was required, obtained based on the shareholders' own capital, who consider recovering said investment in the first year of operation. The profitability provided to shareholders is 249% which makes our project a profitable business. / Trabajo de investigación
145

Concepts et développements pour la production de cellulose blanchie, pure ou oxydée à partir de matière lignocellulosique à recycler / Concepts and developments for the production of bleached, pure or oxidized cellulosic pulp from recycled lignocellulosic material.

Dollie, Lucas 27 May 2019 (has links)
Les papiers et cartons récupérés sont aujourd’hui recyclés en nouveaux matériaux similaires, en particulier les vieux cartons sont transformés en nouveaux cartons. Riches en matière lignocellulosique, les cartons récupérés pourraient remplacer le bois dans la production de produits de plus haute valeur ajoutée. Ainsi la thèse a exploré le potentiel de procédés existants de délignification, blanchiment et purification, appliqués sur des mélanges fibreux simulant la composition de différents cartons, pour la production de pâte papetière blanchie et de pâte à dissoudre.Le traitement appliqué est composé d’une cuisson Kraft, suivie d’une séquence de blanchiment classique D0-Ep-D1 puis, dans le cas de la production de pâte à dissoudre, d’une purification de type CCE. Les cartons à traiter ayant des compositions fibreuses variables, toute l’étude a été conduite sur des mélanges fibreux modèles, composés de fibres de pâte Kraft écrue et de pâte mécanique. Dans tous les cas, des pâtes blanchies ont été produites, même si leur degré de polymérisation est parfois en deçà des standards. En revanche, les pâtes sont difficiles à purifier. Par ailleurs, il a été montré que la qualité du produit final, les performances des procédés et leur impact environnemental, dépendent de la composition fibreuse du mélange. Enfin le traitement d’un carton industriel a révélé que les charges minérales contenues dans le matériau limitent sa revalorisation.La faible qualité des pâtes blanchies obtenues a conduit à tester une autre voie de valorisation, la production de cellulose oxydée pour MFC. Un nouveau procédé de pré-oxydation pour les pâtes Kraft écrue a été développé : il combine blanchiment et oxydation du substrat dans un stade unique en utilisant le catalyseur TEMPO avec du dioxyde de chlore et de l’hypochlorite de sodium. Des MFC de qualité équivalente à celles produites à partir de pâte blanchie préoxydée par le système TEMPO/NaClO/NaBr ont été obtenues. / Today recovered papers and boards are recycled into similar products; in particular old corrugated boards are transformed into new corrugated boxes. Rich in lignocellulosic material, recovered carton boards might replace wood for the production of hgiher added-value products. The thesis investigated the potential of existing delignification, bleaching and purification processes, applied on fibre mixes simulating the composition of various carton boards, for the production of bleached paper pulp and dissolving pulp grades.The treatment was composed of a Kraft cook, followed by a conventional D0-Ep-D1 bleaching sequence, and in the case of dissolving pulp production, a CCE stage for cellulose purification. Because carton boards exhibit various fiber compositions, all the study has been conducted on model mixes, made of fibres from unbleached Kraft pulp and mechanical pulp. In all cases, bleached pulps have been successfully obtained, although pulp viscosity was sometimes below the standards. However the bleached pulps were found difficult to purify. Moreover, it has been shown that the quality of the final product, the performances of the processes and their environmental impact, depended on the fiber composition of the mix. Finally, the treatment of an industrial carton board revealed that mineral fillers contained in the material limit its upcycling.Because of the low quality of the bleached pulp produced, another valorization way was tested: the production of oxidized cellulose for MFC. A new pre-oxidation process for unbleached Kraft pulp has been developed, combining bleaching and oxidation of the substrate in a single stage combining stage combining the use of TEMPO as a catalyst, chlorine dioxide and sodium hypochlorite. MFC of same quality as those produced from bleached Kraft pulp pre-oxidized by the classical TEMPO/NaClO/NaBr system have been obtained.
146

Influência da qualidade da madeira de híbridos de Eucalyptus grandis x Eucalyptus urophylla e do processo Kraft de polpação na qualidade da polpa branqueada / Wood quality influence of Eucalyptus grandis X Eucalyptus urophylla hybrids and Kraft pulping process in bleached pulp quality

Santos, Sheila Rodrigues dos 21 October 2005 (has links)
O presente estudo analisou a influência de clones do híbrido de Eucalyptus grandis x Eucalyptus urophylla, com densidades básicas e cargas de álcali ativo diferentes, no processo de polpação e branqueamento. As características e propriedades das polpas não-branqueadas, licor preto residual, branqueamento, morfologia e propriedades físico-mecânicas das polpas branqueadas foram analisadas para avaliar os efeitos dos fatores clone e carga de álcali ativo. As polpações foram realizadas aplicando-se cargas de álcali ativo de 12,5%, 13,5% e 14,5%. Em seguida, as polpas não-branqueadas foram submetidas a uma pré-deslignificação com oxigênio e branqueadas através da seqüência D0EOPD1. As polpas branqueadas foram refinadas em moinho PFI e analisadas quanto às resistências físico-mecânicas. Os resultados obtidos indicam que a madeira do clone G-31 apresentou menor densidade básica e teor de holocelulose, e maiores teores de extrativos totais e lignina Klason comparativamente à madeira do clone C-41. Os clones mostraram rendimentos bruto e depurado semelhantes. O clone G-31 produziu polpa com menor número kappa na menor carga alcalina e polpa com maior número kappa na maior carga alcalina revelando uma importante interação significativa clone x álcali ativo. Os fatores álcali ativo, clone e interação clone x álcali ativo tiveram influências nos parâmetros avaliados na polpação. Os licores residuais dos clones apresentaram valores semelhantes de pH, teor de sólidos solúveis, densidade e álcalis residuais. O clone G-31 consumiu mais álcali ativo residual. O fator que exerceu maior influência nestes parâmetros foi a carga de álcali ativo. O branqueamento mostrou para o clone G-31 maior eficiência na prédeslignificação com oxigênio e menor número kappa. A viscosidade intrínseca da celulose branqueada e a alvura foram mais elevadas para o clone C-41. O aumento da carga alcalina reduziu ligeiramente a alvura do clone G-31 e elevou a alvura do clone C-41. Os fatores álcali ativo, clone e interação clone x álcali ativo tiveram influências nos parâmetros avaliados no branqueamento. A fibra da polpa branqueada do clone G-31 apresentou, significativamente, maiores comprimento, espessura da parede, índice de enfeltramento, fração parede e índice de Runkel; e menores diâmetro do lume, coeficiente de flexibilidade e "coarseness". O menor valor de "coarseness" mostrou fibras mais leves na polpa do clone G-31. O fator clone exerceu a maior influência nas propriedades físicas e mecânicas da polpa branqueada. A polpa branqueada do clone G-31 apresentou, significativamente, menor número de revoluções no moinho PFI para atingir o índice de tração de 70 N.m/g, baixo grau Schopper Riegler para atingir este nível de tração e gerou folhas com valores mais elevados de volume específico e opacidade. Estas características e propriedades permitiram concluir que a polpa do clone G-31 foi a mais atrativa e indicada para a fabricação de papéis de imprimir e escrever. A polpa branqueada do clone C-41 apresentou valores mais elevados de volume específico aparente e ascensão capilar Klemm quando analisadas sem refino. Estas propriedades foram mais evidentes nas cargas alcalinas mais elevadas. A polpa do clone C-41 mostrou características mais favoráveis para a fabricação de papéis para fins sanitários. / The present study has analyzed the influences of Eucalyptus grandis x Eucalyptus urophylla hybrid clones with different specific gravity and active alkali charges in the bleaching and pulping process. The characteristics and properties of unbleached pulp, residual black liquor, bleaching, bleached fiber morphology and bleached pulp physical-mechanical properties were analyzed to evaluate the effects of the active alkali charge and clone factors. The pulping were realized applying active alkali charges of 12,5%, 13,5% and 14,5%. Then, the unbleached pulps were submitted to an oxygen delignification and bleached with the sequence D0EOPD1. The bleached pulps were refined using PFI mill and the physical-mechanical properties were analyzed. The results showed that G-31 wood clone presented lower specific gravity and holocellulose content and higher total extractives and Klason lignin contents when compared to C-41 wood clone. Both of them showed similar pulp yield total and screening. The G-31 clone produced pulp with lower kappa number in the lowest alkaline charge and pulp with higher kappa number in the highest alkaline charge showing an important significant interaction between clone and active alkali. The factors active alkali, clone and clone x active alkali interaction influenced in the evaluated parameters in the pulping. The clones residual black liquor showed similar values of pH, soluble solids content, density and residual alkalis. The G-31 clone consumed more residual active alkali. The factor that exerted the highest influence in these parameters was the active alkali charge. The bleaching showed that the G-31 clone has higher efficiency in the oxygen delignification and lower kappa number. The bleached pulp viscosity and brightness were higher for C-41 clone. The increase in the alkaline charge reduced slightly the G-31 clone brightness and elevated the C-41 clone brightness. The factors active alkali, clone and clone x active alkali interaction influenced in the bleaching parameters evaluated. The fiber of the G-31 bleached pulp showed, significantly, higher length, wall thickness, felting index, wall ratio and Runkel index, and lower lumen diameter, flexibility coefficient and coarseness. The lowest value of coarseness showed lighter fibers in the G-31 pulp. The factor clone exerted the highest influence in the physical and mechanical properties of the bleached pulp. The G-31 bleached pulp showed, significantly, lowest revolutions number in the PFI mill to reach tensile index of 70 N.m/g, low Schopper Riegler degree to reach this tensile index and generated sheets with higher values to bulk and opacity. These characteristics and properties allow to conclude that G-31 pulp was the most attractive and indicated to produce printing and writing papers. The bleached pulp of C-41 clone showed higher values of bulk and capillarity Klemm when analyzed without refining. These properties were more evident in the highest alkaline charges. The C-41 pulp showed characteristics more favorable to the production of tissue papers.
147

Filbornaverket : En analys på ombyggnationen av pannan med avseende på kväveoxidutsläpp / Filbornaverket : An analysis of the reconstruction of the boiler regarding nitrogen oxide emissions

Hedlund, Ingemar, Ovenmark, Erik January 2019 (has links)
Studiens syfte var att studera en ombyggnation av SNCR-anläggningen i Filbornaverket, enavfallseldad rosterpanna, på uppdrag av Öresundskraft Kraft & Värme AB. Anledningen var attse om en minskning av NOx-utsläpp var möjlig då det innebär en minskning av försurning avskog och mark. Naturvårdsverket har som mål att minska mängden NOx-utsläpp genom attanvända sig av ekonomiska styrmedel.Filbornaverket är en panna på cirka 60 MW fjärrvärmeeffekt och 18 MW eleffekt. Metodensom användes var en jämförande metod. Ombyggnationen ledde till en minskning av NOxutsläppunder perioden oktober till november 2018 på 5,45% jämfört med samma period2017. Detta innebar en årlig besparing på cirka 250 000 kr i minskade NOx-avgifter tillNaturvårdsverket för Öresundskraft Kraft & Värme AB. Mängden insprutad ammoniak blev igenomsnitt 4,73% lägre 2018 jämfört med 2017. / This study examined the reconstruction of the SNCR equipment in Filbornaverket, a wasteburning grate boiler, on behalf of Öresundskraft Kraft & Värme AB. The purpose was to see ifa reduction of NOx was possible. A reduction of NOx means a reduction in acidification offorest and land. Naturvårdsverkets goal is to reduce the amount of NOx by using economiccontrol means.Filbornaverket is a boiler of about 60 MW district heating power and 18 MW electrical power.A comparative method was used in this study. The reconstruction lead to a reduced amountof NOx during the period October to November 2018 of 5,45% compared to same period2017. This means an annual saving of around 250 000 kr in reduced NOx-fees toNaturvårdsverket for Öresundskraft Kraft & Värme AB. The amount of injected ammonia wasin average 4,73% lower during 2018 compared to 2017.
148

Avaliação tecnológica de clones-elite de Eucalyptus spp., crescendo no Estado de Goiás: qualidade do lenho para produção de polpa celulósica Kraft / Technological assessment of Eucalyptus wood elite clones growing in Goiás State: wood quality for kraft pulp production

Santos, Deborah Rodrigues de Souza 28 June 2018 (has links)
O setor florestal brasileiro prevê forte expansão das florestas plantadas de eucalipto, o que torna essencial estudos que indiquem materiais genéticos superiores e adaptados a novas fronteiras regionais. O estado de Goiás tem se destacado como um território com grande potencial ao estabelecimento e expansão de novos plantios. Nesse sentido, o presente trabalho tem como objetivo a avaliação tecnológica de clones-elite de Eucalyptus spp., oriundos de um teste clonal instalado no município de Luziânia- GO, com foco na qualidade do lenho para produção de polpa celulósica Kraft. Do total de materiais genéticos do teste clonal, foram selecionados 6 clones híbridos de Eucalyptus spp, na idade de 4 anos, e cortadas 5 árvores de cada clone, obtendo-se discos de madeira em 6 posições longitudinais (0% (base), DAP, 25%, 50%, 75% e 100% da altura comercial) e 4 toretes (±50 cm de comprimento) em posições intermediárias. Os discos de madeira foram utilizados na determinação das características físicas, químicas e anatômicas dos clones e os toretes, transformados em cavacos, submetidos à polpação Kraft e avaliadas as características do cozimento. Os resultados indicam grande variabilidade entre os clones nas características avaliadas. Os seis clones diferiram quanto ao crescimento e volume, com destaque para os clones A, B, C e F, de melhores desempenho. Os valores médios de densidade básica ponderada observados para os clones de estudo (0,46-0,50 g/cm3), se encontram dentro da faixa considerada ideal para a produção de celulose. Foram observados valores médios de densidade aparente entre 0,56 e 0,65 g/cm3, sendo o maior valor verificado para o clone E. Em geral, foi observado efeito significativo apenas na variação radial das propriedades físico-anatômicas. A caracterização química do lenho dos seis clones indica potencialidade tecnológica para produção de celulose Kraft, com destaque ao clone E. Os melhores desempenhos na polpação kraft para Kappa ± 18, foram alcançados com os clones E e F. Os clones de Eucalyptus spp. do estudo, em sua maioria, apresentaram excelente adaptabilidade local e satisfatórias propriedades do lenho quanto à transformação tecnológica em polpa celulósica Kraft. O clone E, que apresentou menor teor de extrativos e maior teor de holocelulose em sua constituição, além de bom desempenho no processo de polpação Kraft, bem como o clone F, que obteve os melhores índices de crescimento e produvidade e satisfatórias características físicas, anatômicas e tecnológicas, foram indicados como os de maior potencial para a produção de celulose. Ressalta-se a importância de se desenvolver pesquisas futuras nos materiais em idade mais avançada, visando melhor qualificar a adaptação local, bem como a qualidade do lenho, em busca de maior alcance no desempenho e eficiência produtiva do processo de polpação celulósica. / The Brazilian forestry sector foresees a strong expansion of Eucalyptus forests, which makes essential studies indicating superior genetic material and adapted to new borders. Goiás state has stood out as a territory with great potential for the establishment and expansion of new forest plantations areas. In this sense, the aim of the present work was to evaluate the technological performance of Eucalyptus wood elite clones from a clonal test installed in the municipality of Luziânia-GO, focusing on the wood quality for kraft pulping. From the total genetic material of the clonal test, 6 Eucalyptus wood hybrid clones, at 4 years-old, were selected and 5 trees of each clone were cut, obtaining wooden discs in 6 longitudinal positions (0% (base), DBH, 25%, 50% , 75% and 100% of commercial height) of trunck. Also, 4 logs of 50 cm in length between the base and 100% of the commercial height. The wood discs were used for determining the physical, chemical and anatomical wood characteristics and the short logs were transformed into wood chips for kraft pulping that whose characteristics were evaluated. The results indicate a high variability among the clones. All clones differed in volume growth, especially clones A, B, C and F, with the best performances. The average values of weighted basic density observed in Eucalyptus spp. clones (0.46-0.50 g/cm3) are within the range considered ideal for the kraft pulping production. Average values of apparent density were observed between 0.56 and 0.65 g / cm3, being the highest value verified for clone E. In general, a significant effect of radial position of the trunk was observed only for physical-anatomical properties. The wood chemical characterization indicates, for all clones, technological potential for kraft pulp production, especially for clone E, with lower content of extractives and higher content of holocellulose,. The best performances of kappa number 18 of kraft pulping were observed in clones E and F. Eucalyptus wood clones, presented excellent adaptability and great wood technological properties. The clone E, which presented besides good performance in the kraft pulping process, as well as clone F, which obtained the best rates of growth and productivity and satisfactory physical, anatomical characteristics, were the ones with the best kraft pulping potencial. Future researches with the same Eucalyptus spp. trees at advanced ages are recommended, in order to provide a better information of local adaptation as well wood quality, in search of greater reach in the performance and productive efficiency of the kraft pulping process.
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Sistemas multiagentes para controle inteligente da caldeira de recuperação. / Multi-agent systems for the intelligent control of a recovery boiler.

Herrera Sosa, Ivan Raul 11 September 2007 (has links)
Engenheiros têm introduzido um melhor suporte para procedimentos de monitoramento de condições complexas através da aplicação de sistemas descentralizados inteligentes usando uma variedade de técnicas de inteligência artificial. Agora é largamente reconhecido que estes problemas decorrentes da complexidade funcional do monitoramento de condições podem ser resolvidos com arquiteturas que contenham muitos módulos distribuídos e inteligentes, que interajam dinamicamente, os quais são chamados de agentes inteligentes. A tecnologia baseada em agentes tem gerado muita agitação nos últimos anos por causa da promessa de ser um novo paradigma na hora de definir os conceitos para modelar e implementar sistemas de controle. O objetivo do presente estudo é implantar esta tecnologia no controle de uma caldeira de recuperação com a finalidade de gerenciar e integrar produção, qualidade e segurança no processo. A caldeira de recuperação tem dois objetivos bem definidos, cada um com suas restrições operacionais: (1) geração de vapor vivo a ser utilizado no processo, e, (2) redução de reagentes inorgânicos para recuperar sulfeto e carbonato de sódio, necessários no ciclo do processo de fabricação de celulose. Cada um destes objetivos é um sistema com funções independentes dentro da caldeira, mas que, no entanto tem seus desempenhos interligados entre si através das variáveis comuns existentes no processo. Esta é exatamente a definição de um sistema agente, ou melhor, de um Sistema Multi-Agente (SMA), no qual não existe uma otimização e sim a busca de uma solução possível. O modelo dinâmico da Caldeira foi simulado em Matlab(TM) Simulink(TM) baseado no modelo matemático da caldeira de recuperação de licor negro B&W (Babcock&Wilcox). O SMA foi desenvolvido utilizando a linguagem de programação JAVA e a plataforma de agentes JADE. / Engineers have been introducing better support for procedures of monitoring complex conditions through the application of intelligent decentralized systems, implementing a variety of artificial intelligent techniques. Nowadays it is vastly known that these problems that are consequence of the functional complexity of monitoring conditioning can be solved trough architectures, built by many intelligent distributed modules, which interact dynamically, known as intelligent agents. Technology based on agents have been creating excitement over the last years because of its promise of being a new paradigm that can be used to define modeling and implementing concepts for control systems. The goal of this thesis is to implement this new technology on controlling a recovery boiler, aiming to manage and integrate production, quality and security to the process. The operation of the recovery boiler has two well defined objectives, each one with its operational constraints: (1) steam production, an important asset in the pulp and paper process, and, (2) reduction of inorganic reagents to recover sulfate and sodium carbonates, the necessary chemicals in the Kraft pulp production. Each one of these functions, is an independent system inside the recovery boiler, however they have their performances connected to each other by common variables present in the process. This is exactly the definition of an agent system, in other words, a definition of a Multi-Agent System (MAS), for which there is not an optimization, but the search for the best possible outcome. The recovery boiler dynamic model was simulated using Matlab(TM) Simulink(TM) based on the mathematic model of B&W (Babcock&Wilcox) recovery boiler of black liquor. The MAS was implemented using JAVA(TM) programming language and JADE(TM) agent platform.
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Análise exergética dos sistemas térmicos em um processo de produção de celulose e papel. / Exergy analysis of thermal systems in a pulp and paper production process.

Santos, Moisés Teles dos 08 March 2007 (has links)
Este trabalho apresenta uma avaliação comparativa de desempenho termodinâmico de sistemas térmicos em uma unidade industrial de fabricação de celulose e papel Kraft. Foram coletados dados de projeto e operação para o sistema atual de utilidades e de um novo sistema em fase de implantação. A análise exergética é utilizada como ferramenta de avaliação quantitativa e qualitativa para os principais componentes do sistema de cogeração de energia: caldeiras de força, caldeiras de recuperação química, turbinas e válvulas redutoras. Diferentes critérios de desempenho globais e relativos são determinados através de balanços simultâneos de energia e entropia (balanços exergéticos). As irreversibilidades ou entropia gerada nos sistemas são determinadas através da exergia destruída. Esta abordagem revela os principais pontos onde a energia é degradada em sua qualidade, indicando onde devem ser buscadas alternativas de otimização termoeconômica para um melhor aproveitamento dos recursos energéticos disponíveis. / This work presents a comparative evaluation from thermodynamic performance view of thermal systems in a Kraft pulp and paper mill. The design information and the data of the industrial operation were collected for the current utility system and for the new system that has been buit. The exergy analysis is applied as the quantitative and qualitative evaluation tool for the main energy conversion systems: power boilers, chemical recovery boiler, turbines and throttling valves. Different global and relatives performance criteria are estimated by simultaneous energy and entropy balances (exergy balances). The irreversibility or generated entropy in the systems is determined by the destroyed exergy. This approach reveals the places where energy quality is mainly degraded and shows where alternatives for optimization must be sought for a better use of the available energetic resources.

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