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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.
31

Mistura diesel, biodiesel e etanol anidro : uma possibilidade para reduzir o custo de produção da cadeia da cana-de-açúcar / Blending diesel, biodiesel and ethanol anhydrous : is a possibility to reduce the cost of the production chain of sugar cane

Moretti, Ricardo Roquetto, 1982- 23 August 2018 (has links)
Orientador: Waldir Antonio Bizzo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-23T09:38:07Z (GMT). No. of bitstreams: 1 Moretti_RicardoRoquetto_M.pdf: 3138518 bytes, checksum: 3ee2db245fb6caad13e782dc3c9072a2 (MD5) Previous issue date: 2013 / Resumo: A emissão de poluentes por veículos automotores é um dos grandes problemas ambientais enfrentados na atualidade. Para resolver o problema de emissão de poluentes à modificação da matriz energética foi o caminho adotado, e para isso realizaram-se investimentos em tecnologias para fabricação de motores com melhor eficiência térmica e capazes de operar com biocombustíveis. No Brasil etanol foi o combustível objeto de estudo para realizar a mudança na matriz energética, por ser um produto produzido em larga escala no Brasil. Durante o estudo realizou-se uma revisão bibliográfica sobre os processos de produção de etanol, biodiesel e óleos vegetais. Avaliou-se a viabilidade técnica e financeira de se utilizar uma mistura de combustível óleo diesel, biodiesel versus o desempenho da mistura óleo diesel, biodiesel e etanol anidro em um motor de ignição por compressão visando não acarretar perda de performance no motor. Para a avaliação do desempenho global do motor utilizou-se um motor ciclo diesel comercial, operando com 95% de óleo diesel e 5% biodiesel e comparou-se esse mesmo motor utilizando uma mistura de 92,15% de óleo diesel, 4,85% de biodiesel e 3% de etanol anidro / Abstract: This work investigated the feasibility of using a blend of standard Brazilian diesel (which contains 5% biodiesel) and up to 5% ethanol. We characterized the mixture as fuel and measured the performance of a diesel engine operating with a blend containing 3% anhydrous ethanol, the maximum percentage of ethanol that did not reduce the cetane number of the fuel below that specified in Brazilian legislation (ANP Resolution 42). The presence of anhydrous ethanol in the mixture did not cause a significant impact on engine performance as measured by brake power, brake torque and brake specific fuel consumption tests. The thermal efficiency of the engine used in the tests was slightly higher with standard diesel than with the diesel-biodiesel-ethanol blend / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica
32

Biodiesel production over supported nano-magnesium oxide particles

Mguni, Liberty Lungisani 10 April 2013 (has links)
M.Tech. (Chemical Engineering) / There are a number of processes for the production of biodiesel. Homogenous catalysed processes are the most popular in large scale production due to short reaction times and less extreme reaction conditions. Despite this, homogenous catalysts have a number of disadvantages which include: high probability of soap formation in the presence of water and free fatty acids; they cannot be re-used since some of the catalyst is consumed during the reaction and the separation of the remaining catalyst from the product is difficult. In contrast, heterogeneous catalysts offer simplified production and purification processes. However, their reaction rates are low due to mass transfer restrictions. This work looked at the unsupported and supported nano-MgO as solid catalyst for soybean oil transesterification reaction. More research is being undertaken to overcome these low reaction rate problems. Nano-MgO was used since it has been considered as a bridge between homogenous and heterogeneous catalysts. It was supported to enable easy separation from the reaction products.
33

Syngas, mixed alcohol and diesel synthesis from forest residues via gasification - an economic analysis

Koch, David 19 December 2008 (has links)
Liquid transportation fuels can be produced by gasification of carbon containing biomass to syngas( a gaseous mixture of CO and H2) with subsequent conversion of the syngas to fuels. One possible process is the so called mixed alcohols synthesis, which produces a mixture of ethanol and higher alcohols. Another possible process is the reaction of syngas to Fischer-Tropsch liquids, mainly diesel fuel. This study examines the economics of syngas, ethanol and diesel fuel production from lignocellulosic biomass (southern pine residues). The process is modeled with Aspen Plus, a process simulation software package. The process is simulated for plant sizes between 715 and 2205 dry tons/day. The feedstock moisture content is varied between 20% and 50% and the feedstock costs are varied between $30/dry ton and $80/dry ton. The influences of the examined variables on the minimum product selling price are determined. The economic effects of an integration of the mixed alcohols and the FT diesel process with a kraft mill are also evaluated.
34

Regeneration of diesel particulate filters: Effect of renewable fuels

Rodríguez-Fernández, José, Lapuerta, Magín, Sánchez-Valdepeñas, Jesús 21 December 2020 (has links)
Current trends in diesel transport anticipate that in the upcoming future a range of renewable fuels will be necessary to comply with emission and sustainability legislations. Exhaust after-treatment devices such as diesel particulate filters –DPFs– will have to operate satisfactorily with this pool of biofuels. In particular, DPF regeneration is crucial to cut the fuel penalty and guarantee an acceptable lifetime for this device. In the present work, an automotive diesel engine was run with fossil fuel and three renewable fuels: a conventional biodiesel, a fuel manufactured through Fischer-Tropsch –FT– process and a HVO biofuel. The DPF was loaded and regenerated through an active process with fuel post-injections. Additionally, soot samples were investigated with thermo-gravimetry (TGA) and calorimetry (DSC) to confirm whether these techniques obtain relevant information for explaining DPF behavior. Both methods proved that biodiesel leads to a more economical regeneration being the biodiesel soot, more reactive than the other samples, the main reason. DPF regenerations with paraffinic fuels (FT-derived and HVO) did not reveal strong differences compared to diesel, though TGA and DSC results suggested that soot from paraffinic biofuels is more reactive than that from diesel. The exhaust gas temperature and composition are behind this apparent discrepancy.
35

Commercial biodiesel production in South Africa : a preliminary economic feasibility study

Nolte, Mirco 03 1900 (has links)
Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2007. / Biodiesel, a fatty acid alkyl ester, derived from the transesterfication of vegetable oil, is considered a renewable fuel that can be used as a replacement for fossil diesel. The urgency for biofuel production in South Africa is motivated by the vulnerability of crude oil prices, high unemployment, climate change concerns and the need for the growing economy to use its resources in a sustainable manner. The technical feasibility of biodiesel production has been proven and this study investigates its preliminary economic feasibility in South Africa by looking at the market, financial and agricultural feasibility of commercial biodiesel production. / ENGLISH ABSTRACT: Biodiesel, a fatty acid alkyl ester, derived from the transesterfication of vegetable oil, is considered a renewable fuel that can be used as a replacement for fossil diesel. The urgency for biofuel production in South Africa is motivated by the vulnerability of crude oil prices,high unemployment, climate change concerns and the need for the growing economy to use its resources in a sustainable manner. The technical feasibility of biodiesel production has been proven and this study investigates its preliminary economic feasibility in South Africa by looking at the market, financial and agricultural feasibility of commercial biodiesel production. The market feasibility. The potential market size for biodiesel in South Africa is about 1 billion litres if it is to replace 10% of its diesel consumption by 2010. However, governmental legislation and policies are needed to create a predictable and growing market for biodiesel in South Africa. These policies or regulations could be in the form of subsidising feedstock for biodiesel production, subsidising the biodiesel itself, using government purchasing power, mandatory blending legislation, tax incentives or price compensation agreements. The financial feasibility. Calculations to asses the financial feasibility of commercial biodiesel production are based on a 2500 kg/h (22.5 million litres/annum) containerized plant. This size is based on findings of Amigun & von Blottnitz (2005) that the optimum biodiesel plant size in South Africa ranges between 1500 and 3000 kg/h. Two types of plants were considered, namely a seed extraction biodiesel production (SEBP) plant using locally produced oilseeds as feedstock and a crude oil biodiesel production (COBP) plant using imported crude vegetable oil as feedstock. The capital investment for a SEBP plant ranges between R110 and R145 million while a COBP plant would require a capital investment of about R45 to R50 million. These amounts include a working capital of about R35 million due to money that is fixed in a 3 month stock supply.Feedstock and raw material contribute to about 80% of the manufacturing cost while transport costs are the second biggest contributor. These results point to the fact that the plant location is very important in order to minimize production costs. Thus, commercial biodiesel production should not be centralized, but should rather happen through greater number of relatively small plants located in oilseed producing regions. (South Africa would require about 46 plants each producing 2500 kg/h to produce 10% of its diesel by 2010). The sensitivity analyses showed that the manufacturing costs of a SEBP plant are very sensitive to changes in oilseed and oilcake prices while the manufacturing costs of a COBP plant are very sensitive to a change in crude vegetable oil price. The fluctuating nature of the agricultural commodity prices makes biodiesel manufacturing costs predictable. Soybean biodiesel costs are the most sensitive to price changes while sunflower biodiesel costs are the least affected. An increase in glycerol price would decrease the manufacturing costs of biodiesel by about 12 cents/litre for every R1000/ton increase in price. Glycerol prices are currently too low to consider in the calculations due to a global oversupply as a result of biodiesel production. The break even price of biodiesel is calculated by adding R1.01/litre fuel tax to the manufacturing cost, which means that biodiesel produced from oilseeds (except canola) will not be able to compete with the current price of fossil diesel (30 August 2006) without subsidies or legislation. The agricultural feasibility. Producing 10% of South Africa’s diesel using oilseeds would require a major production increase.Biodiesel production will also increase the local oilcake supply which means South Africa will change from being a net-importer of oilcake (730 thousand tons/year) to a net-exporter of oilcake (1.7 million tons/year). Land availability for such a production increase is not a problem which means that the agricultural resources and potential market are available to produce and absorb 10% of the countries diesel in the form of biodiesel. However, at the moment the commercial production of biodiesel does not seem financially feasible without any government imposed legislation or subsidies. / AFRIKAANSE OPSOMMING: Biodiesel, ‘n hernubare brandstof wat uit groente olie vervaardig word, is ‘n moontlike plaasvervanger vir petroleum diesel. Biodiesel vervaardiging in Suid Afrika word aangespoor deur hoë kru olie pryse, hoë werkloosheid syfers, toenemende bewustheid van klimaatveranderings en druk op ‘n groeiende ekonomie om sy bronne volhoubaar te gebruik. Die vervaardiging van biodiesel is relatief maklik en hierdie studie is ‘n voorlopige ondersoek in die ekonomiese lewensvatbaarheid van komersiële biodiesel produksie in Suid Afrika deur te kyk na die mark, finansiële en landbou lewensvatbaarheid daarvan. Die mark lewensvatbaarheid. Die potensiële grote vir ‘n biodiesel mark in Suid Afrika is omtrent 1 miljard liter indien dit 10% van sy petroleum diesel teen 2010 wil vervang, maar wetgewing sal nodig wees om ‘n voorspelbare en groeiende mark te skep. Hierdie wetgewing kan in die vorm van subsidies vir boere of biodiesel produsente wees, gebruik maak van regerings koopkrag, verpligtende inmeng maatreëls, belasting voordele of prys vergoeding ooreenkomste. Die finansiële lewensvatbaarheid. Berekeninge om die finansiële lewensvatbaarheid te bepaal is op ‘n 2500 kg/uur (22.5 miljard liter/jaar) gedoen. Hierdie aanleg grote is gebaseer op inligting verkry deur Amigun & von Blottnitz (2005) wat sê dat die optimale grote biodiesel aanleg in Suid Afrika tussen 1500 en 3000 kg/uur is. Daar is na twee tipe aanlegte gekyk, naamlik na ‘n saad ekstraksie biodiesel vervaardigings (SEBP) aanleg wat plaaslike oliesade as voer materiaal gebruik en ‘n kru olie biodiesel vervaardigings (COBP) aanleg wat ingevoerde groente olie as voer materiaal gebruik. 'n SEBP aanleg het ‘n kapitale belegging van tussen R100 en R145 miljoen nodig terwyl ‘n COBP aanleg slegs tussen R45 en R50 miljoen nodig het. Hierdie bydrae sluit werkende kapitaal van omtrent R35 miljoen in wat vas is in 3 maande se voer materiaal kostes. Die onderstaande tabel wys die vervaardigings kostes vir albei tipe aanlegte en verskillende voer materiale. Omtrent 80% van die kostes is voer materiaal terwyl vervoerkostes die tweede hoogste bydraer is. Hierdie resultaat wys na die feit dat die aanleg ligging ‘n baie belangrike rol speel om vervaardigins kostes te minimeer. Dus word die stelling gemaak dat kommersiële biodiesel vervaardiging nie in ‘n paar sentrale aanlegte moet plaasvind nie, maar eerder in ‘n klomp verspreide relatief kleiner aanlegte moet plaasvind. Hierdie kleiner aanlegte sal in die oliesaad produserende streke versprei moet wees. (Suid Afrika sal omtrent 46 aanlegte nodig hê wat elk 2500 kg/uur produseer om 10% van sy diesel teen 2010 te kan vervaardig). Die sensitiwiteits analise het gewys dat die kostes van ‘n SEBP aanleg baie sensitief vir veranderings in oliesaad en oliekoek pryse is. Die kostes van ‘n COBP aanleg is baie sensitief vir veranderinge in groente olie pryse. Wisselvallige landbou pryse maak die kostes van biodiesel baie wisselvallig en onvoorspelbaar. Sojaboon biodiesel kostes is die sensitiefste vir prys veranderings terwyl sonneblom saad die minste geaffekteer word deur sulke prys veranderings. Vir elke R1000/ton wat die glyserol prys styg sal die vervaardigings kostes van biodiesel met 12 sent/liter daal. Die glyserol prys is op die oomblik te laag om in ag te neem weens ‘n oormaat glyserol in die wêreld mark as gevolg van biodiesel produksie. Die gelykbreek prys van biodiesel word uitgewerk deur R1.01/liter brandstof belasting by die vervaardigings kostes by te tel. Op die oomblik (30 Augustus 2006) kan biodiesel van oliesade (behalwe kanola) nie met die petroleum diesel prys meeding nie sonder enige subsidies of wetgewing. Die landbou lewensvatbaarheid. Die landbou implikasies om 10% van die land se diesel uit oliesade te vervaardig word in die onderstaande tabel uiteengesit. Hierdie resultate is gebaseer op die feit dat al drie oliesade gebruik word vir biodiesel vervaardiging en dat die oppervlak verhouding van die drie oliesade konstant bly soos die produksie vermeerder. Biodiesel vervaardiging sal ook die plaaslike oliekoek produksie vermeerder sodat Suid Afrika sal verander van ‘n netto-invoerder (730 duisend ton/jaar) tot ‘n netto-uitvoerder (1.7 miljoen ton/jaar) van oliekoek. Land beskikbaarheid vir so ‘n vermeerderde produksie is nie ‘n probleem nie wat beteken dat Suid Afrika wel die landbou bronne en potensiële mark het om 10% van sy diesel te vervaardig en te absorbeer in die vorm van biodiesel. Uit `n finansiële oogpunt lyk dit egter asof die kommersiële vervaardiging van biodiesel in Suid Afrika nie lewensvatbaar sal wees, sonder enige wetgewings of subsidies, nie. / Centre for Renewable and Sustainable Energy Studies
36

Effect of oxygenated additives in conventional fuels for reciprocating internal combustion engines on performance, combustion and emission characteristics.

Siwale, Lennox Zumbe. January 2012 (has links)
D. Tech. Mechanical Engineering. / Discusses how to reduce the negative impacts of petroleum oil based fuels in reciprocating engines on the environment through the use of oxygenated (alcohol) blends, while not deteriorating engine performance. The specific objectives are as follows: To evaluate the performance characteristics of n-butanol-diesel blends: B5, B10 and B20, in a direct-injection turbo-charged diesel engine and to compare findings with a study that was carried out by others (Sayin, 2010). To compare the performance, combustion and emission characteristics of dual alcohol-gasoline with single alcohol-gasoline blends fired in a naturally-aspirated (NA) spark ignition (SI) engine. To compare the combustion and emission characteristics of dual alcohol (methanol-n-butanol-gasoline) blends with single alcohol (methanol-gasoline) blends in a single-cylinder SI engine. To evaluate the combustion and regulated emission characteristics of DF and n-butanol/diesel blends (B5, B10, and B20 where B5 represents 5 % shared volume of n-butanol to 95 % diesel fuel) fired in a high load turbo-charged diesel engine and to compare the findings with a study that was conducted by Raslavicius & Bazaras, (2010).
37

Estudo dos principais precursores de ozônio na região metropolitana de São Paulo / Study of major precursors ozone in the metropolitan area of São Paulo

ALVIM, DEBORA S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:41:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:38Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
38

Estudo do efeito da radiação ionizante em compostos orgânicos do diesel e do petróleo: hidrocarbonetos, sulfurados e nitrogenados / Study on ionizing radition effects in diesel and crude oil: organic compounds: hydrocarbon, sulfur and nitrogen

ANDRADE, LUANA dos S. 10 November 2014 (has links)
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2014-11-10T10:40:38Z No. of bitstreams: 0 / Made available in DSpace on 2014-11-10T10:40:38Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
39

Estudo dos principais precursores de ozônio na região metropolitana de São Paulo / Study of major precursors ozone in the metropolitan area of São Paulo

ALVIM, DEBORA S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:41:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:38Z (GMT). No. of bitstreams: 0 / O ozônio (O3) é um dos poluentes que representa grande preocupação em termos de qualidade do ar na Região Metropolitana de São Paulo (RMSP). No ano de 2012 foram observados 98 dias de ultrapassagens do padrão horário da qualidade do ar para este poluente na RMSP. A exposição aos poluentes atmosféricos como O3 e outros está associada ao prejuízo da saúde respiratória. O enfoque deste estudo é determinar os principais Compostos Orgânicos Voláteis (COV) precursores de O3 para auxiliar no controle deste poluente. Neste trabalho foram realizadas 78 amostragens durante a semana de hidrocarbonetos no ano de 2006 e 66 amostragens de hidrocarbonetos, 62 de aldeídos e 42 de etanol durante o ano de 2011/2012, 7:00 h às 9:00 h, na estação CETESB IPEN/USP. Medidas de COV também foram realizadas no ano de 2006 e 2008, na Estação CETESB Cerqueira César. Adicionalmente, foram efetuados testes de emissões veiculares durante o ano de 2009 de 5 veículos a diesel, 3 a etanol, 2 a gasolina C e 1 motocicleta. O modelo de trajetórias OZIPR foi utilizado para determinar os principais precursores de O3. Durante o ano de 2011/2012, na Estação CETESB IPEN/USP, a classe de aldeídos representou 35,3% dos COV analisados em concentração na atmosfera, seguido pelo etanol 22,6%, compostos aromáticos 15,7%, alcanos 13,5%, cetonas 6,8%, alcenos 6,0% e alcadienos < 0,1%. Considerando a concentração dos compostos e sua reatividade, as simulações executadas com o modelo OZIPR mostraram que o acetaldeído contribuiu com 61,2% da formação do O3 na atmosfera da RMSP no ano de 2011/2012. Dos COV analisados, a classe dos aldeídos contribui com 74% da produção de O3, aromáticos 14,5%, alcenos 10,2%, alcanos 1,3% e alcadienos (isopreno) 0,03%. O estudo de emissão veicular mostrou que 39% dos aldeídos foram provenientes de veículos a etanol, 28% a diesel, 26% a gasolina C e 7% de motocicletas. As emissões dos COV por veículos a gasolina contribuíram com 44% da formação de O3, a diesel 22%, a etanol 19% e motocicletas 15%. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
40

Estudo do efeito da radiação ionizante em compostos orgânicos do diesel e do petróleo: hidrocarbonetos, sulfurados e nitrogenados / Study on ionizing radition effects in diesel and crude oil: organic compounds: hydrocarbon, sulfur and nitrogen

ANDRADE, LUANA dos S. 10 November 2014 (has links)
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2014-11-10T10:40:38Z No. of bitstreams: 0 / Made available in DSpace on 2014-11-10T10:40:38Z (GMT). No. of bitstreams: 0 / O petróleo é uma das principais fontes de energia e também de poluição no mundo atual. Novas tecnologias na indústria petroquímica visam diminuir a energia gasta no processamento e a redução dos produtos poluidores. Compostos de enxofre e nitrogênio geram problemas ambientais, sendo os mais relevantes, a poluição da atmosfera que afeta a saúde da população diretamente. A tecnologia nuclear tem sido usada na proteção ambiental através da remoção de poluentes pela reação com radicais livres produzidos pela ação da radiação nas moléculas de água. O objetivo desse trabalho é a avaliação do efeito da radiação ionizante no petróleo e no diesel, principalmente, nos hidrocarbonetos, nos compostos orgânicos sulfurados e nos nitrogenados. Para tanto estudou-se a molécula modelo de enxofre, benzotiofeno, e amostras de diesel e de petróleo bruto. As amostras foram irradiadas na fonte de Co-60 do tipo Gammacell. A concentração total de enxofre nas amostras foi determinada por fluorescência de raios x e os compostos orgânicos foram determinados por cromatografia gasosa acoplada ao espectrômetro de massas,GC-MS. O estudo com a molécula modelo demonstrou que cerca de 95% foi degradado com uma dose absorvida de 20 kGy. Os resultados obtidos na análise dos hidrocarbonetos demonstram que estes foram craqueados quando irradiados com a dose de 15 kGy, entretanto observouse a polimerização e a baixa eficiência no craqueamento em doses maiores. Observou-se eficiência na redução da maioria dos compostos de enxofre do petróleo e diesel. Considerando as doses estudadas as que apresentaram melhor eficiência foram as de 15 kGy e 30 kGy. Na amostra de diesel as maiores variações nos compostos orgânicos foi observada com doses absorvidas de 30 kGy e 50 kGy. No petróleo, após a destilação e separação cromatográfica de coluna aberta utilizando cloreto de paládio como fase estacionaria, observou-se a separação preferencial de compostos orgânicos sulfurados. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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