Modelagem de dados de equilíbrio para misturas de CO2 e hidrocarbonetos leves sob altas pressões

Abstract

Due to the large amount of compounds present in the crude oil, for example, hydrocarbons and carbon dioxide, it is necessary knowledge of the thermodynamic properties of these mixtures and the vapor-liquid equilibrium, as industrial processes for obtaining their derivatives gasoline, diesel, naphtha, kerosene, among others, use these properties to determine the quantities of heat and work necessary to carry out these processes. For fluid, these properties are often evaluated from measurements of the molar volume as a function of temperature and pressure, providing relationships between pressure, volume and temperature (PVT), which can be expressed as state equations. This paper consists of listing and evaluating the thermodynamic consistency experimental data balances available in the literature for the binary systems (CO2 - CH4/C2H6/C3H8/C4H10) and ternary (CO2/CH4/C2H6 and CO2/CH4/C3H8) with temperatures in the range of 207 to 419,9 K and pressures of 0,389 up to 84,080 atm. Thus, we used the cubic equation of state Peng-Robinson and Van der Walls quadratic mixing rule for the estimation of parameters (Kij) through SPECS simulator with the data selected in order to provide a basis for the description quantitative real behavior of fluids and generalized correlations which allow the prediction of PVT behavior of fluids for which there is availability of experimental data. The average errors observed for the correlation of binary systems was up 5%, while for the ternary prediction showed slightly larger errors of up to 7%, the cubic equation PR efficient in the calculations of these systems, for the simple modeling, but with quantitative descriptions and satisfactory predictive character.