Tesis:
Biodiesel from microorganisms and other alternative feedstocks : production, composition and properties
- Autor: BOLONIO MARTÍN, David
- Título: Biodiesel from microorganisms and other alternative feedstocks : production, composition and properties
- Fecha: 2018
- Materia: Sin materia definida
- Escuela: E.T.S.I. DE MINAS Y ENERGÍA
- Departamentos: ENERGIA Y COMBUSTIBLES
- Acceso electrónico: http://oa.upm.es/51676/
- Director/a 1º: CANOIRA LÓPEZ, José Laureano
- Director/a 2º: GÓMEZ FERNÁNDEZ, Luis
- Resumen: The increasing demand of energy, the dependence of fossil fuels and the concerns about climate change encourage the search of sustainable energy sources. Biofuels are believed to have an important role in the coming energy transition and are supported by both European and American current policies. Biodiesel has already been proved to be an alternative to diesel and is currently used by many countries in biodiesel-diesel blends. However, recent studies have pointed out the non-sustainability of biodiesel when it is produced from current oils like soybean, palm, rapeseed and sunflower. Moreover, some car manufacturers are worried to increase the percentage of biodiesel blends because of the possible reduction in fuel quality, hence, the properties of biodiesel and their relation with its composition are an important matter that must be carefully considered. This thesis studies new biodiesel sources and assesses their properties, with the ultimate goal of showing sustainable and feasible alternatives to the current oils used for the production of biodiesel, aiming to improve the sustainability of the energy sources, reduce the dependence of fossil fuels and develop knowledge to move toward a circular economy. Main properties of biodiesel made from different sources are estimated from their composition, proposing new equations to estimate the oxidation stability, cold flow performance and lubricity of fatty acid ethyl esters (FAEEs), a type of biodiesel that uses bioethanol, instead of commonly used methanol, which currently has a fossil origin. Of all the studied sources, microorganisms have the hugest potential to become sources of biofuels. In this thesis, the bacteria Escherichia coli is genetically modified to change its fatty acid composition improving the final properties of the biodiesel obtained from these fatty acids. Moreover, this thesis examines a supercritical process for FAEEs production from animal fat with high content of free fatty acids, one of the biggest problems of waste feedstocks. The degradation of polyunsaturated compounds, a common problem of this kind of process, is assessed. Besides, FAEEs from grapeseed oil, with a huge potential in wine producing countries as Spain, have been evaluated. The macroalga Chaetomorpha cf. gracilis grown in Cuban wetlands, an alternative to avoid the excessive use of land, has been characterized to assess its potential as a biofuel and, lastly, biodiesel from desert plants from Tunisia has been produced and its properties analyzed, an interesting alternative because of their low need of water and their ability to grow in arid lands.