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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

Building and controlling a prototype biogas plant

von Heideken, Philip January 2016 (has links)
The purpose of this project is to build a prototype biogas plant with a cheap control system. The plant is a prototype of a real plant, onto which the control system is to be attached in the future. The prototype does not produce gas, since it has water and air as input substances. The substances are however controlled in the same way as in a gas producing plant. The plant is built mostly of garden hose equipment and plastic buckets. The control system consists of several Arduino Nano which reads sensor values and process the data. All necessary sensor values are displayed by a computer on a graphic interface written in Labview.   The result was a functional control system with some issues as unbalance between outflowing and inflowing amount of water in the digester, difficulties with calibration of the temperature sensor. Therefore it needs further work and testing before attaching on the real plant.
2

Reforma a seco do metano para produção de hidrogênio utilizando catalisadores Ni/Al2O3 : uma alternativa para o biogás

Schwengber, Carine Aline January 2015 (has links)
Orientador : Prof. Dr. Helton José Alves / Co-orientador : Prof. Dr. Ricardo José Ferracin / Dissertação (mestrado) - Universidade Federal do Paraná, Setor Palotina, Programa de Pós-Graduação em Bioenergia. Defesa: Palotina, 13/03/2015 / Inclui referências / Área de concentração / Resumo: A reforma a seco (RS) do metano está se tornando um assunto desafiador, atraindo cada vez mais atenção, pois é um processo relevante do ponto de vista ambiental uma vez que consome CH4 e CO2, gases responsáveis pelo efeito estufa, além de produzir o gás H2 que por sua vez, é o combustível que possui maior poder calorífico. Atualmente, quase 95% da produção mundial de hidrogênio é a partir de matériasprimas à base de combustíveis fósseis, principalmente o gás metano. Neste sentido, o biogás é uma fonte promissora pois é produzido pela decomposição anaeróbia de resíduos vegetais e animais, e é composto tipicamente de 55 a 75% de CH4 e 25 a 44% de CO2, associados a traços de outros gases. Ni suportado em ?-Al2O3 é um dos catalisadores mais utilizados nos processos de reforma do CH4. Neste trabalho foram preparados catalisadores 15% Ni/Al2O3 e 30% Ni/Al2O3, pelo método da impregnação úmida, e caracterizados pelas técnicas: absorção atômica em chama (teor metálico), fisissorção de N2, RPT, DRX, DTP-NH3, IV e MEV. Para condução dos ensaios reacionais catalíticos, foi construído e instalado um reator contínuo tubular, sendo estudadas as variáveis reacionais: temperatura de reação (600 a 700 ºC), velocidade espacial (VHSV de 15 e 45 L.h-1.gcat-1) e tempo reacional (até 10 h). Nas reações de RS o aumento da temperatura de reação levou a maiores produções de H2 e conversões de CH4 e CO2, porém evidenciou-se a maior formação de coque. Em geral as melhores conversões foram observadas nas reações conduzidas com o catalisador 15% Ni/Al2O3. Nas reações variando a velocidade especial, observou-se que o aumento da velocidade espacial (VHSV de 45 L.h-1.gcat-1) ocasionou diminuição nas conversões de CH4, indicando que a maior quantidade de catalisador no leito catalítico foi favorável à reação de reforma. Os resultados dos testes conduzidos durante 10 horas de reação, indicaram que não ocorreu perda da atividade catalítica significativa ao longo da reação. Palavras-chave: reforma a seco, hidrogênio, biogás, catalisador, níquel, alumina. / Abstract: Dry reforming of methane (DR) is becoming a challenging subject, attracting increasingly the attention, because it is an important process from an environmental point of view as it requires CH4 and CO2 gases responsible for the greenhouse effect, in addition to producing the H2 gas which in turn is the fuel that has a higher calorific value. Currently, almost 95% of world hydrogen production is from raw materials based on fossil fuels mainly methane gas. In this sense, the biogas is a promising source because it is produced by the anaerobic decomposition of plant and animal waste, and is typically compound from 55 to 75% CH4 and 25% to 44% from CO2, associated with traces of other gases. The Ni supported on ?-Al2O3 catalysts is one of the most used in the CH4 reform processes. In this work were prepared catalysts 15% Ni/Al2O3 and 30% Ni/Al2O3, by the method of wet impregnation and characterized by techniques: flame atomic absorption (metal content), N2 physisorption, RPT, XRD, DTP-NH3, IV and SEM. For conducting the catalytic reaction test, was built and installed a tubular continuous reactor, being studied the reaction variables: reaction temperature (600 to 700 °C), space velocity (VHSV at 15 and 45 h-1.gcat-1) and time reaction (up to 10 h). In the reactions of RS the increased reaction temperature led to higher yields of H2 and CH4 conversion and CO2, but showed increased to coke formation. In general the best conversions were observed in reactions conducted with the catalyst 15% Ni/Al2O3. In particular reactions varying the space speed, it was observed that increasing space velocity (VHSV 45 h-1.gcat-1) caused a decrease in CH4 conversion, indicating that the increased amount of catalyst in the catalyst bed was favorable to the reform reaction. The results of tests conducted for 10 hours reaction, indicated that there was no significant loss of catalytic activity during the reaction. Keywords: dry reforming, hydrogen, biogas, catalyst, nickel, alumina.
3

Enhancing the anaerobic digestion of poultry manure through nutrient supplementation via duckweed biomass

Clark, Piers Benedict January 1994 (has links)
No description available.
4

Jämförelse av två mätmetoder för mindre gasvolym

Nilsson, Lina January 2007 (has links)
<p>Two different methods for measuring biogas production were used, gas meter and gasbags. The gas meters were electronic and counted each time a certain gasvolume passed through them. The gasbags collected the gas that hade passed through the gas meter until a manual measuring could be done. The two different methods gave the same result for a volume at three liters but for a volume around 0,2 liters they did not. Accuracy and precision for the gasbags was more exact than for the gas meters even if the method was difficult with a lot of different elements that could affect the result. The gasbag method was more complicated and took longer time than the gas meter, which was an easy working technic that wasn´t time consuming. But both of the methods gave a fall off . For the gasbags the values falled off because of leakage and for the gas meter it falled off because of dubble counting and that the meters stopped count for a while. The advantage of the gasbags is that you can measure the gas total compound. The benefit of the gas meter is that you can measure changes in the gas flow over time.</p>
5

Jämförelse av två mätmetoder för mindre gasvolym

Nilsson, Lina January 2007 (has links)
Two different methods for measuring biogas production were used, gas meter and gasbags. The gas meters were electronic and counted each time a certain gasvolume passed through them. The gasbags collected the gas that hade passed through the gas meter until a manual measuring could be done. The two different methods gave the same result for a volume at three liters but for a volume around 0,2 liters they did not. Accuracy and precision for the gasbags was more exact than for the gas meters even if the method was difficult with a lot of different elements that could affect the result. The gasbag method was more complicated and took longer time than the gas meter, which was an easy working technic that wasn´t time consuming. But both of the methods gave a fall off . For the gasbags the values falled off because of leakage and for the gas meter it falled off because of dubble counting and that the meters stopped count for a while. The advantage of the gasbags is that you can measure the gas total compound. The benefit of the gas meter is that you can measure changes in the gas flow over time.
6

Uppgradering av biogas i systemperspektiv med avseende på miljöpåverkan och kostnader / Biogas upgrading in a systems perspective with respect to environmental impact and economic cost

Kovac, Elvedin January 2013 (has links)
Swedish biogas is currently produced mainly by anaerobic digestion of sewage sludge at sewage treatment plants, landfills and anaerobic digestion of household or industrial waste. Also cattle ma-nure from farms can be used to produce biogas. Upgrading biogas represents an increase in methane concentration from about 65 % to about 97 %. In addition, particles and contaminants must be sepa-rated from the upgraded biogas. There are various methods for upgrading and this report compares six different methods with respect to environment and economy: water scrubber, Biosling, cryo technology, chemical absorption, Pressure Swing Adsorption (PSA) and membrane separation. According to the used ORWARE model, chemical adsorption with amine has the least environmen-tal impact (methane emissions) and the lowest costs. The chemical used in the method is very good at reducing CO2 and chemical adsorption gives an upgraded gas containing around 99 % methane. The downside of amine is that it contributes to the acidification of the environment and additional heat is needed to free the CO2. It is also a small scale method. PSA and membrane separation shall be avoided when it comes to environmental impacts. When it comes to the economy, it is more dif-ficult to compare the methods. The reason is that the scale does matter together with factors such as geography. The methods are also improving and modernizing. It is important to consider this and be up to date when investing in a new biogas upgrading plant.
7

Small-scale biogas production in the province of Pampanga, Philippines

Trosgård, Emma January 2015 (has links)
The purpose of this study was to contribute to sustainable development in the Pampanga province, Philippines. The Philippines are facing several major environmental problems; pig production represents a major contributing factor to pollution and eutrophication of water bodies in the country. At present there is no requirement for purification of wastewater from backyard (small-scale) farms. With the help of anaerobic digestion the manure could be used to produce biogas. The study’s objective was to determine an anaerobic digester design and substrate composition for small-scale biogas production in backyard farms (20 pigs). To achieve this objective, several goals were defined; (1) determine the best substrate composition for biogas production, through the use of lab experiments, (2) determine a design best suited for small-scale use, (3) test the substrate and design in-field, (4) determine the impact of different inoculum, (5) determine a small-scale design based on local conditions such as finance, building materials, climate etc., (6) evaluate the digestates’ properties as a bio-fertilizer and (7) compare the biogas production with an existing biogas plant in Pampanga. Four combinations of food waste and pig manure were tested at Karlstad University’s biogas lab. The best composition had VS-ratio 1:2 for pig manure to food waste, and produced 111.1 NmL CH4/g VSadded. The chosen design was a floating drum digester. It was tested together with the substrate and two inoculums (cow manure and digestate from an existing biogas plant) in four pilot plants during 32 days. The plants showed symptoms of inhibition in biogas production and the pH dropped to toxic levels (below pH 6). At the end of the study, the plants had similar cumulative biogas production. The mean production was 1764 NmL and the average methane content was 33.6%. The plants with inoculum from an existing biogas plant showed signs of recovering from the low pH. The plants with cow manure as inoculum showed increasing signs of inhibition. The mean phosphorus content of the digestate was 1.3% TS and nitrogen content was 6% TS. The carbon to nitrogen ratio was on average 8:1, which had a positive impact on nitrogen mineralization in the soil (if used as bio-fertilizer). The digestate had high levels of VFA, which reflected improper substrate composition. The large fraction of food waste was the likely cause of inhibition; easily digestible carbohydrates lead to the pH drop and high levels of VFA. Based on the field study and literature, another substrate composition was recommended for the final design. The suggested substrate had VS-ratio 2:1 for pig manure to food waste. A variant of the floating drum digester was recommended, where several digesters could be connected in series and the number of digesters could be adapted to the number of pigs. The digester volume was 6.2 m3; the expected biogas production was 2.6 m3 with 70% methane content. This facility would result in a digestate containing 0.2 kg phosphorus and 0.7 kg nitrogen per day. Comparisons between the existing plants’ biogas production and the pilot plants could not be done due to the fact that the plant lacked methods for measuring their biogas production and methane content. However, the study’s overall findings make a strong argument for the use of biogas in backyard farms, for mitigating many of the Philippines’ water quality issues arising from pig production.
8

Operation of Solid Oxide Fuel Cells on Anaerobically Derived Wastewater Treatment Plant Biogas

Lackey, JILLIAN 08 September 2012 (has links)
Solid Oxide Fuel Cells (SOFCs) have been researched for operation on anaerobic digester (AD)-derived biogas at wastewater treatment plants (WWTPs). SOFCs can perform well on light hydrocarbon fuels and the use of AD-derived biogas provides an opportunity for biogas to be used as a renewable fuel. Tests were conducted at three levels of H2 dilution (using N2, Ar and CO2 as diluent gases, plus H2O) to examine the performance of tubular SOFCs. When gases that are inert in SOFC reactions are used there is a decrease in cell performance. When CO2 was used the decrease in cell performance was higher due to the reverse water-gas shift (WGS) reaction reducing the partial pressure of H2. A computer simulation was developed to predict SOFC system efficiency and GHG emissions. The simulation indicated that the system electrical efficiency is higher for a S/C ratio of 2 then a S/C ratio of 1 due to the increased partial pressure of H2 in the reformate. The reduction in GHG emissions is estimated to be approximately 2,400 tonnes CO2, 60 kg CH4 and 18 kg N2O, annually. Testing was conducted using a simulated biogas reformate mixture that was developed through a research initiative in which urban areas with populations over 150,000 in the United States and 50,000 in Canada were solicited to participate in a survey of biogas composition. The biogas reformate composition was determined to be 66.7% H2, 16.1% CO, 16.5% CO2 and 0.7% N2, which was then humidified to 2.3 and 20 mol% H2O. The reformate tests conducted at the higher humidification level yielded a better performance than those at the lower humidification because the WGS reaction produced more H2 when additional H2O was provided. It was concluded that WWTP AD-derived biogas, when cleaned effectively to remove H2S, Si compounds, halides and other contaminants, could be reformed to provide a clean, renewable fuel for SOFCs. Biogas/SOFC systems could provide electricity and heat to WWTPs, as well as reduce GHG emissions, thus reducing their energy costs and environmental impact. / Thesis (Master, Civil Engineering) -- Queen's University, 2012-08-31 15:38:28.122
9

Implementation of a Biogas-system into Aquaponics : Determination of minimum size of aquaponics and costs per kWh of the produced energy

Gigliona, Julia January 2015 (has links)
Aquaponics might be one solution to produce food in a more sustainable way in the future. Aquaponics combines aquaculture and hydroponics in a way that the disadvantages of one system become the advantages of the other one. The nutrient rich excess water from the fish tank is used for plant growth, while the plants are used as biofilter to clean the water for the fish. Further closed loops can be created by using plant-residues, sludge and food wastes as raw materials for a biogas digester. With a combined heat and power plant (CHP) the produced methane can be used for heat and electricity production needed by the aquaponics. This report determines if such implementation can lead to reduced overall running costs and which size the aquaponics should have. As example location Sweden is chosen.It shows that the methane demand of a CHP requires a minimum size of the biogas digesters and aquaponics. In the aquaponics at least 50 t of fish have to be bread with a complementing grow bed area of 800 - 900 m2. In total the aquaponics system contains 1000 m3 water. The Energy produced by the CHP will not cover totally the energy demand of the aquaponics-system and should be complement by energy from other sources (e.g. solar cells, wind turbines) if there is no access to a stable external energy supply. Energy produced by the CHP has an average price between 1 - 2.1 kr/kWh. If no CHP is implemented, there is no minimum size required for the aquaponics- and biogas-system and the produced methane can be used for heating and cooking.
10

Desenvolvimento de tecnologias para compressão de biogás

Souza, José de January 2010 (has links)
O crescimento do potencial energético a partir da biomassa estimula o desenvolvimento e a criação de novas tecnologias neste setor. Neste trabalho realizou-se uma ampla pesquisa da produção, compressão e acondicionamento do biogás. Constatou-se durante essa pesquisa a necessidade da busca por alternativas que possibilitem a utilização eficiente deste biocombustível. Analisou-se a possibilidade da fabricação de um compressor alternativo para biogás que possa ser aplicado em pequenas unidades de produção por meio da modelagem das partes componentes. Primeiro efetuou-se a escolha do material considerando-se as características adequadas para construção do sistema de compressão. Depois disto dimensionou-se a camisa de compressão e a sua modelagem tridimensional com software Inventor 2010 (versão Student), além de válvulas e matrizes para fabricação. Complementarmente foi simulado o funcionamento do compressor (gráfico do deslocamento, velocidade e força com o software FluidSim da Festo Didatic). Por último executou-se o projeto eletropneumático, energização e lista de dispositivos necessários para montagem do compressor. Observou-se que essa tecnologia pode ser aplicada em pequenas plantas de produção de biogás. A comparação com outros sistemas de compressão revelou vantagens como a não haver contaminantes na compressão e acionamento, além da compressão poder se dar em ambiente separado do seu acionamento. / The growth of the energy potential from the biomass stimulates development and creation of new technologies in this sector. In this work is carried out extensive research in production, compression and biogas bottling. The need to search for alternatives has been evidenced during the research to make possible the efficient use of biofuel. After it analyzed the possibility of manufacturing of an alternative compressor for biogas which can be applied in small production units through the modeling of the contracting parties. At first it was effected the material choice considering the characteristics for the construction of the compression system. After this, was dimensioned a compression jacket, valves and matrices with the Student software Inventor 2010. Moreover the functioning of the compressor was simulated (its graphical of the displacement, speed and force with a FluidSim software from Festo Didatic). Finally was made a pneumatic project and was executed a list of necessary devices for the compressor assembly. It was observed to that this technology can be applied in small plants of production of biogas. The comparison with other systems of compression demonstrates that tis compressor haven’t contaminants, beyond the compression to be able to give itself in separate environment of its drive.

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