| Popis: |
Researches focusing on the development of biofuel production processes have increased significantly in recent years, mainly for environmental and economic issues. The identification of low-cost raw materials and the development of simulation models able to predict the conditions of production and the properties of the components may be the way to optimize these processes. Biodiesel is an alternative renewable fuel to petroleum-based diesel departing from vegetal oils (fresh or reused) as well as some kinds of animal tallows. The knowledge of thermophysical properties of the components of the feed is crucial for optimization this process. The experimental determination of these properties is complex and high costs, as can occur chemical degradation during analysis or it is impossible to have them this like pure components. Thus, the objective of this study was to evaluate methods for predicting physical and thermodynamic properties, in order to develop a database of the compounds involved in the biofuels production's process and to recommend appropriate methods based on accuracy and consistency of data obtained. In view of that, this work investigated the performance of groups contribution methods and fragment-based approach in the calculation of as normal boiling temperature, critical temperature, critical pressure, critical volume, acentric factor, heat capacity, vapor pressure, enthalpy of vaporization liquid density and enthalpy of formation. At the end of this work, the most viable models were recommended for each property evaluated, comparing the estimated values to the experimental data available in the literature. Finally, a database with physical and chemical properties of vegetable oils was created to use in engineering calculations. |
