Alberto Llamas

Fatty acid methyl and ethyl esters obtained from rare seeds from Tunisia: Ammi visnaga, Citrullus colocynthis, Datura stramonium, Ecballium elaterium, and Silybum marianum

ABSTRACT This work aims to study the properties of fatty acid methyl and ethyl esters from Tunisian oils in order to assess their potential use as biofuel sources. The oils chosen for this study have been scarcely researched by other authors and are very interesting for a possible exploitation as fuels. Most of them are nonedible sources and all of them can be grown in arid places with no need of supplementary water: the bishop’s weed Ammi visnaga, the bitter apple Citrullus colocynthis, the stramonium Datura stramonium, the devil pickle Ecballium elaterium, and the milk thistle Silybum marianum.

Polycyclic Aromatic Hydrocarbons (PAHs) produced in the combustion of fatty acid alkyl esters from different feedstocks: Quantification, statistical analysis and mechanisms of formation

Polycyclic Aromatic Hydrocarbons (PAHs) are pollutants of concern due to their carcinogenic and mutagenic activity. Their emissions are mainly related with the combustion or pyrolysis of the organic matter, such as in fossil fuels combustion. It is important to characterize PAHs in the combustions of biofuels due to their increasing importance in the actual energetic setting. There is a lot of research focused in PAHs emission due to the combustion in diesel engines; but only few of them have analyzed the effect of raw material and type of alcohol used in the transesterification process. Different raw materials (i.e. animal fat, palm, rapeseed, linseed, peanut, coconut, and soybean oils) have been used for obtaining FAME and FAEE. A method for measuring PAHs generated during combustion in a bomb calorimeter has been developed. Combustion was made at different oxygen pressures and the samples were taken from the bomb after each combustion. Samples were extracted and the PAHs amounts formed during combustion were analyzed by GC-MS. This research shows the statistical relationships among the 16 PAHs of concern, biodiesel composition and oxygen pressure during combustion.

Geographical variability of the composition and properties of fatty acid methyl esters from Citrullus colocynthis in Tunisia

ABSTRACT Biofuels are a promising alternative to substitute petroleum-based transportation fuels and could contribute to sustainable development. This work studies the composition and properties of the fatty acid methyl esters (FAMEs) obtained from Citrullus colocynthis, a plant that grows in arid and dry conditions. Samples from seven locations in Tunisia were collected to study the possible variability in their composition and properties to assess the performance in a combustion engine. Results show suitable properties and future studies are encouraged to assess the potential productivity at a large scale, regarding that domestication of the plant could contribute to improving its quality and productivity.

Fatty acid methyl esters (FAME) from oleaginous seeds grown in arid lands. Part II: Ibicella lutea, Onopordum nervosum, Peganum harmala, Smyrnium olusatrum and Solanum elaeagnifolium

ABSTRACT The properties of fatty acid methyl esters (FAMEs) obtained from Tunisian oleaginous seeds, grown in arid places with no need of supplementary water, are studied to assess their potential use as biodiesel: devil horn Ibicella lutea, cotton thistle Onopordum nervosum arabicum, Sirian rue Peganum harmala, horse celery Smyrnium olusatrum and silverleaf nightshade Solanum elaeagnifolium. Some key properties such as cloud point, pour point, cold filter plugging point, oxidation stability, cetane number, density, kinematic viscosity, heating value and oxygen extended sooting index have been predicted using equations that correlate the above properties with their ester profiles.