Deoxygenation of waste cooking oil and non-edible oil for the production of liquid hydrocarbon biofuels

Deoxygenation of waste cooking vegetable oil and Jatropha curcas oil under nitrogen atmosphere was performed in batch and semi-batch experiments using CaO and treated hydrotalcite (MG70) as catalysts at 400 °C. In batch conditions a single liquid fraction (with yields greater than 80 wt.%) was produced containing a high proportion of hydrocarbons (83%). In semi-batch conditions two liquid fractions (separated by a distillation step) were obtained: a light fraction and an intermediate fraction containing amounts of hydrocarbons between 72-80% and 85-88% respectively. In order to assess the possible use of the liquid products as alternative fuels a complete chemical characterization and measurement of their properties were carried out.

Oxygen tensioactivity on liquid-metal drops

The influence of oxygen on the surface tension of liquid metals is a topic of undoubted interest as the formation of oxide films, or even oxygen contamination of the metal interface, represents the main source of error in determining the surface tension. The evaluation of gas-atmosphere mass exchanges under stationary conditions allows the evaluation of an effective oxygen pressure at which the oxidation of metal becomes evident. This effective oxygen pressure can be considered as a property of the system and, according to experimental evidence, can be many orders of magnitude greater than the equilibrium pressure. The measurement of the surface tension is a good way of studying interface properties, their temporal change and their connections to transport and reaction rates. This paper represents a review of a work undertaken with the aim of understanding oxygen mass transport at the liquid metal surface in relation to the study of capillary phenomena at high temperature.