Analysis of the physical and chemical characteristics of vegetable oils as fuel

Possible relationships between physical and chemical properties of vegetable oils as biofuels have been studied. 19 samples of vegetable oils of different types and origin were considered. First the relationship between the viscosity of each oil and the temperature was studied. Subsequently, single and multiple regression analyses were carried out between viscosity, iodine number, saponification number and calorific value. It was observed that temperature has a key role in controlling the level of viscosity of the oils, and the relationship between viscosity and temperature is specific to each type of product. Moreover, the chemical structure of the tryglicerides conditions to a great extent the physical, mechanical and energy characteristics of the oil. In particular the length of the carbon chains and the unsaturation level are related to the value of viscosity in a single and multiple relationship. The calorific value increases with the increase in the length of the carbon chain. This study could be useful to develop simplified methods for controlling the quality of vegetable oils as biofuels and for improving the technology of their energy transformation