Publicação
Produção de biocombustíveis líquidos por hidrogenação, a partir de efluentes orgânicos da indústria do azeite
| Resumo: | The disrespected way as the Human kind subsisted on Earth, their excessive growth and denoted presence through the depletion of resources, the emission of polluting gases to the atmosphere, and the inappropriate occupation of land, caused serious alterations in the cycles of the ecosystem in which we live. The depletion of oil reserves associated with the commonly used global energy pattern motivated communities to a sustainable awareness in order to find alternatives to fossil fuels and technologies currently used, and capable of supplying the needs of all sectors in different companies. The use of residues of plant or animal origin in the production of advanced fuels has aroused the interest of the scientific community because, besides being evidenced as an alternative to the treatment of these residues, it results in their transformation into products of interest. The present work consists of the evaluating of the potential of converting effluents of vegetable origin, from the oil sector into a liquid product, rich in hydrocarbons. The conversion processes used in this study were hydrogenation and pyrolysis. During these processes, the triglycerides present in the vegetative oils undergo saturation reactions, where carbon bonds decompose and compounds similar to petroleum derivatives are produced. Initially, the reaction temperature effect for both processes was studied at 380 °C, 400 °C and 420 °C, with an initial pressure inside the autoclave of 0.55 MPa and a reaction time of 30 minutes. For both processes studied, it was observed that the increase of the reaction temperature promotes the occurrence of more intense cracking reactions, which leads to the formation of smaller compounds. For both tests, occurring at 420 °C, conversion of alkanes such as n-C5 and n-C6 was greater than the other tests. Finally, the effect of changing the reactional atmosphere from reactive (hydrogen) to inert (nitrogen) was analyzed. For the temperature of 380 °C, it was found that the use of a reactive atmosphere allows to obtain products of better quality, that is, in the range of conventional fuels, between n-C14 and n-C18. The increase in temperature in this study revealed that, for the pyrolysis process, cracking reactions are more intense, since a greater amount of lower chain alkanes has been identified. The process that allowed to obtain a greater amount of liquid product was the hydrogenation, in the test occurred at a temperature of 420°C. However, with regard to the analysis of the composition of the species of hydrocarbons present in the different distillates, the similarities between the proportions identified for different process tests shows that the use of hydrogen as reaction gas is not an aggregate value in view of its cost. |
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| Autores principais: | Samúdio, Miguel Alves |
| Assunto: | Hidrogenação Pirolise Efluentes Óleo vegetal Combustíveis avançados Teses de mestrado - 2018 |
| Ano: | 2018 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | português |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | The disrespected way as the Human kind subsisted on Earth, their excessive growth and denoted presence through the depletion of resources, the emission of polluting gases to the atmosphere, and the inappropriate occupation of land, caused serious alterations in the cycles of the ecosystem in which we live. The depletion of oil reserves associated with the commonly used global energy pattern motivated communities to a sustainable awareness in order to find alternatives to fossil fuels and technologies currently used, and capable of supplying the needs of all sectors in different companies. The use of residues of plant or animal origin in the production of advanced fuels has aroused the interest of the scientific community because, besides being evidenced as an alternative to the treatment of these residues, it results in their transformation into products of interest. The present work consists of the evaluating of the potential of converting effluents of vegetable origin, from the oil sector into a liquid product, rich in hydrocarbons. The conversion processes used in this study were hydrogenation and pyrolysis. During these processes, the triglycerides present in the vegetative oils undergo saturation reactions, where carbon bonds decompose and compounds similar to petroleum derivatives are produced. Initially, the reaction temperature effect for both processes was studied at 380 °C, 400 °C and 420 °C, with an initial pressure inside the autoclave of 0.55 MPa and a reaction time of 30 minutes. For both processes studied, it was observed that the increase of the reaction temperature promotes the occurrence of more intense cracking reactions, which leads to the formation of smaller compounds. For both tests, occurring at 420 °C, conversion of alkanes such as n-C5 and n-C6 was greater than the other tests. Finally, the effect of changing the reactional atmosphere from reactive (hydrogen) to inert (nitrogen) was analyzed. For the temperature of 380 °C, it was found that the use of a reactive atmosphere allows to obtain products of better quality, that is, in the range of conventional fuels, between n-C14 and n-C18. The increase in temperature in this study revealed that, for the pyrolysis process, cracking reactions are more intense, since a greater amount of lower chain alkanes has been identified. The process that allowed to obtain a greater amount of liquid product was the hydrogenation, in the test occurred at a temperature of 420°C. However, with regard to the analysis of the composition of the species of hydrocarbons present in the different distillates, the similarities between the proportions identified for different process tests shows that the use of hydrogen as reaction gas is not an aggregate value in view of its cost. |
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