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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.
241

Seleccion de las Mejores Condiciones de Operacion para la Produccion de Bioetanol a Partir de Residuos Agricolas Pretratados con Liquidos Ionicos

Stari Lazo, Leonardo Alfredo January 2011 (has links)
No autorizada por el autor a ser publicada a texto completo / El material lignocelulósico utilizado en el proceso de producción de bioetanol de segunda generación debe pasar por las siguientes etapas: molienda y tamizado, pretratamiento, sacarificación y fermentación, purificación del etanol producido. Resultados de estudios anteriores sugieren que el pretratamiento con líquidos iónicos (IL) aumentaría notablemente la liberación de azucares desde el dicho material. En consecuencia, el objetivo del presente trabajo fue determinar las mejores condiciones de pretratamiento con IL y sacarificación y fermentación simultánea (SSF) para la producción de bioetanol a partir de residuos de trigo y maíz provenientes de los campos de la zona central de Chile. El estudio se dividió en 2 etapas principales: en una primera etapa se buscó encontrar las mejores condiciones de pretratamiento de este tipo de material con el líquido iónico [EMIM+][Cl-] usando las hidrólisis enzimática posterior como criterio para evaluar la calidad del pretratamiento. En la segunda etapa se estudió la fermentación y sacarificación simultánea (SSF) de las muestras de maíz y trigo previamente pretratadas con [emim+][Cl-].De la primera etapa se puede concluir que la variable que afecta de manera significativa el pretratamiento es el tiempo de contacto con el LI, siendo las mejores condiciones en el rango estudiado: un tiempo de pretratamiento de 60 [min]; razón de peso biomasa a peso LI de 1:3, temperatura 150 [ºC]. Al comparar con resultados de estudios anteriores se obtuvo que en el caso trigo este pretratamiento libera un 25% más de glucosa en la hidrólisis enzimática que el pretratamiento con ácido diluido y un 40% más que las mejores condiciones de pretratamiento con hongos de pudrición blanca, tanto para trigo como para maíz. En la segunda etapa se realizó la SSF de muestras de maíz y trigo pretratado con hongos de pudrición blanca y con IL bajo distintas condiciones de operación, manteniendo constantes la temperatura de fermentación en 37 [ºC], el volumen de trabajo en 40 [ml], el microorganismo (M.O.) fermentador (Saccharomyces cerevisiae Red Star) y el tiempo de fermentación en 72-120 [h]. De estos experimentos se concluye que la concentración de material lignocelulósico fermentado afecta significativamente la producción de etanol producido en la fermentación SSF y que, cuando la concentración inicial de microorganismos es alta (1 [g.p.s./L]), la concentración de enzimas también produce diferencias significativas en la producción de etanol . Además, cuando la concentración inicial de enzimas es baja (5 [FPU de celulasa/g]), la concentración inicial de M.O. produce diferencias significativas en la producción de etanol. Las mejores condiciones de operación para la SSF son: pretratamiento con líquido iónico [EMIM+][Cl-] en razón 1:3 a 150 [ºC] durante 60 [min], concentración de sustrato: 1 [g/ 40 ml], concentración enzimas: 20 [FPU de celulasa/g], concentración inicial M.O: 1 [g.p.s./L]. Bajo estas condiciones se alcanza el rendimiento teórico de etanol en fermentaciones (0.511 [g etanol/g glucosa]), produciendo 313 [L etanol/ton de material pretratado]. En conclusión, la fermentación SSF de material pretratado con IL produce resultados alentadores por lo cual se sugiere continuar con este estudio. Se sugiere realizar estudios a mayor escala, utilizar M.Os. capaces de fermentar un mayor espectro de azúcares y realizar un estudio sobre el contenido de azúcares del material post pretratamiento.
242

Evaluación del potencial de sustitución energética en una planta cementera, con compensación de bonos de carbono

Pérez Donoso, Claudia Elena January 2004 (has links)
Memoria para optar al Título Profesional de Ingeniero en Recursos Naturales Renovables / El Protocolo de Kyoto, a través del Mecanismo de Desarrollo Limpio (MDL), permite la negociación de las reducciones de gases de efecto invernadero por medio de la certificación de proyectos aprobados por los gobiernos. Las plantas de cemento representan una fuente importante de emisión de estos gases, principalmente de CO2, que se liberan por la quema de combustibles fósiles, como el carbón, en su proceso de producción. Estos gases pueden ser reducidos si se realiza una sustitución energética parcial por combustibles alternativos, como la biomasa. El propósito de este estudio es evaluar el potencial de sustitución energética en una planta cementera con compensación de bonos de carbono, aprovechando los combustibles biomásicos presentes en la región.
243

Kokultivace kvasinek a mikrořas za účelem produkce obohacené biomasy / Cocultivation of yeasts and microalgae to produce enriched biomass

Bradáčová, Lenka January 2021 (has links)
The diploma thesis is focused on the influence of biological stress formed by co-cultivation of heterotrophic (yeasts) and autotrophic (microalgae and cyanobacteria) organisms on the production of enriched biomass. The monitored groups of substances include carotenoids (-carotene, lutein, lycopene, astaxanthin, torularhodin), chlorophylls A and B, ergosterol and ubiquinone. Further, production of lipids was analyzed in the terms of fatty acid profile and lipid content in biomass. In the first part of the work, the yeast biomass production was investigated using different nitrogen sources. Glycerol was used as a carbon source in all parts of the work. Subsequently, the co-cultivation of yeasts with microalgae and cyanobacteria took place in a multicultivator with gradual increase of selected macroelements – nitrogen, magnesium and phosphorus. The last part of the work was focused on the co-cultivation of yeasts and microalgae in a laboratory fermenter. The best effect on the production of total biomass was the increased magnesium content and high nitrogen content in the basic medium. The best concentrations of carotenoids were achieved due to the double nitrogen and phosphorus content together. Chlorophyll production was significantly lower compared to carotenoids.
244

Návrh čištění odpadních plynů / Design for waste gas cleaning

Kubík, Michal January 2018 (has links)
This diploma thesis deals with impurities in waste gases and syngas. Those gases usually have low heating value and contain impurities which are the main issue of those gas fuels. Waste gases and syngas can replace natural gas after right gas treatment. First part is theoretical. It starts with description of biomass and gasification technology. Then the waste gases are described – their origin and usual composition. Next part is dedicated to impurities and is followed by impurities treatment technologies. For removing of almost every type of impurity wet scrubber can be used which is described in detail in following part. There are other types of gas cleaning technologies, so they are described too but not in such detail as wet scrubber. In second part the wet scrubber is designed, and its function is tested by cleaning syngas from fluidized-bed gasifier called Biofluid. During gas cleaning in wet scrubber the influence of water temperature on efficiency of tar removal is examined.
245

Efektivní a ekologické spalování biomasy / The Effective and Ecological Burning of Biomass

Špiláček, Michal January 2018 (has links)
This work deals with the creation of a numerical model of a biomass combusting chamber on a grate. The research part of this work describes the basic properties of biomass important for its combustion and the biomass combustion process itself. For this process which it is necessary to know the dynamics of the chemical reactions and the overall mechanism of a grate combustion of fuels. It also describes the production of harmful emissions that can be generated by combustion of biomass and the emphasis is mainly on the production of nitrogen oxides. In the next part is described the combustion device itself and the basic mathematical model which incorporates the mechanisms of heat transfer, flow of fluids and transport of chemical species. The basic mathematical model is then extended to a complete mathematical model by determining the initial and boundary conditions. Subsequently, the results of the computer simulation of the mathematical model are presented and commented. The main focus are the emissions of nitrogen oxides and hydrocarbons. These results are used to design an improvement of the geometry of the combustion chamber.
246

Využití spalin pro zplyňování biomasy / The use of flue gas for the biomass gasification

Švácha, Filip January 2019 (has links)
The aim of this thesis is to describe the process of biomass gasification using gas simulating the composition of flue gas – a mixture of oxygen, carbon dioxide and water vapor. In the research part of the thesis the issue of gasification with the focus on fluidized bed gasification and the effect of the gasification medium used on the gasification process is discussed. In the practical part the thesis deals with the design, realization and evaluation of the experiment on a real device. The aim of the experiment is to determine the effect of the exact composition of the mixture of these three media on the gasification process and on the quality of the gas generated. The aim is to find the optimum composition for obtaining gas with the highest possible lower heating value, which contains as little tar as possible. At the end of the work, the results from the experiment are presented and described.
247

Optimalizace peletového kotle pro spalování agropelet / Optimization of Agro-Pellets Boiler

Kurečková, Andrea January 2019 (has links)
The diploma thesis deals with optimization of pellet boiler for agropellets combustion. On the Czech market are mostly available boilers for burning wood pellets. Specially adapted agropellet boilers are pretty expensive. The work is divided into two main parts. The first part contains a research of agropellets, agropellets production and combustions of agropellets. The second part is experimental and describes the combustion test. It describes the measurement procedure, the necessary calculations and evaluation.
248

Dvoukomorový roštový kotel pro spalování digestátu / Digestate Grate Boiler

Krejčiřík, Jiří January 2019 (has links)
This master thesis deals with the properties of digestate in combustion, design of construction solution of digestate boiler and experimental verification of boiler parameters. The first chapter deals with the properties of digestate as a fuel. It is followed by a chapter dealing with the existing measured results on a similar boiler. This is followed by a stoichiometric calculation of the digestate boiler. The next chapter is devoted to combustion chamber models. This chapter is followed by a chapter with experimental verification of chamber models and combustion process tuning. The last chapter contains design of construction and operational measures.
249

Úprava multicyklonu za biomasovým kotlem / Multicyclone treatment behind biomass boiler

Vafek, Petr January 2020 (has links)
The diploma thesis deals with multitube cyclone changes leading to improve separating efficiency of solid particles. The thesis begins with theoretical part, in which the attributes and types of solid particle separators focusing on cyclones are presented. The practical part begins with separating efficiency and pressure drop calculation of the specific multitube cyclone. Subsequently the separating problem is explained and the changes leading to eliminating this problem are presented and evaluated. In the last and main part of thesis the design project including piping design and fan choice is created.
250

Model zplyňování biomasy / Biomass gasification model

Studený, Vojtěch January 2020 (has links)
Mathematical models of gasification are suitable for predicting gas composition and its properties. The aim of the diploma thesis is to compile a mathematical model for biomass gasification. The first part deals with the description of gasification and the technologies used. Theoretical part consists of the search of modeling methods. Other theoretical part is devoted to the description of the model and equations presented in the thesis. Part of the assignment is a parametric study that shows changes in gas production and its properties when changing the parameters. Finally, the model is compared with the data obtained in the experiment on the fluid reactor biofluid 2.

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