Cynara cardunculus as an alternative crop for biodiesel production.
Biodiesel is a renewable fuel obtained from vegetable oils or animal fats, with similar properties<br/>to fossil diesel fuel. It is obtained from the transesterification of the triglycerides with a short<br/>chain alcohol in the presence of a catalyst, giving biodiesel and glycerol in tw...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2006 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/8545 |
| Acceso en línea: | http://www.tdx.cat/TDX-0913107-100410 http://hdl.handle.net/10803/8545 |
| Access Level: | acceso abierto |
| Palabra clave: | biodegradació gasoil Cynara cardunculus biodiesel 504 66 |
| Sumario: | Biodiesel is a renewable fuel obtained from vegetable oils or animal fats, with similar properties<br/>to fossil diesel fuel. It is obtained from the transesterification of the triglycerides with a short<br/>chain alcohol in the presence of a catalyst, giving biodiesel and glycerol in two separated phases.<br/>Traditional raw materials for biodiesel production are the oils of rapeseed, sunflower, soybean<br/>and palm. However, some alternative raw materials such as animal fats, recycled oils and non<br/>conventional crops, are also used.<br/>This thesis is focused on the use of Cynara cardunculus oil for the production of biodiesel. Cynara<br/>cardunculus is a wild cardoon from the family of artichoke that is well adapted to the<br/>Mediterranean weather. The maximum production reaches 2 tons/ha per year of seeds that<br/>contain up to 25 % oil, with a similar composition to sunflower oil. Thus, Cynara cardunculus<br/>cultivation may represent an alternative for abandoned cropland and a good candidate as<br/>renewable energy source and biodiesel production.<br/>In the first part of the work, the reaction conditions where optimised for the transesterification<br/>of unrefined Cynara cardunculus oil. The product obtained was characterised. The acid value of the<br/>original oil (11.8 mgKOH/g) was higher than the values recommended for alkaline<br/>transesterification (1-2 mgKOH/g) resulting in the formation of soaps and gels. For some of the<br/>reaction conditions, the ester and glycerol phases were not clearly separated, reflecting the need<br/>of a preesterification step in order to reduce the acid value of the oil. The preesterification step<br/>was optimised using different reaction temperatures, catalyst and methanol concentrations and<br/>reaction times. The best results were obtained for the reactions conducted at 60ºC, using a 6:1<br/>methanol to oil molar ratio and 0.5% sulphuric acid as catalyst. Finally, the oil was pre-treated<br/>using the best conditions for the preesterification, with an additional degumming step. The<br/>transesterification of the pre-treated oil was optimised and the results were compared to the<br/>previous ones. The ester yield increased with the pre-treatment and the ester and glycerol phases<br/>were clearly separated in most of the cases, showing the advantages of the degumming and<br/>preesterification steps.<br/>The second part of the work was the characterisation of the mixtures of biodiesel and diesel fuel.<br/>European specific normatives for both biodiesel (EN 14214) and fossil diesel fuel (EN 590) were<br/>detailed, together with their requirements and test methods. Mixtures of both fuels at different<br/>proportions, were analysed according to EN 590. Correlations for the mixtures were determined<br/>with experiments or mass balances, according to each case. There are some properties than can<br/>limit the amount of biodiesel allowed in the mixture in order to satisfy the specifications for<br/>diesel fuel, such as density, viscosity, distillation, oxidative stability and cold weather properties. It<br/>was detected the need of specific analytical methods and requirements for some of the properties.<br/>The third part of the work was the analysis of the biodegradability of mixtures of biodiesel and<br/>fossil derived fuels, such as heavy fuel oil, diesel fuel and gasoline. The CO2 evolution test was<br/>used to analyse the biodegradation behaviour of the mixtures. In all the cases cometabolic<br/>biodegradation was observed demonstrating that biodiesel enhances the degradation of the three<br/>fossil derived fuels analysed. The physical properties of the mixtures were also analysed.<br/>UNIVERSITAT ROVIRA I VIRGILI<br/>CYNARA CARDUNCULUS AS AN ALTERNATIVE CROP FOR BIODIESEL PRODUCTION.<br/>Jorgelina Cecilia Pasqualino |
|---|