Precipitação de parafina em misturas de petroleo : medidas experimentais e modelagem termodinamica

AUTOR(ES)
DATA DE PUBLICAÇÃO

1994

RESUMO

The appearance and development of a solid-phase in the liquid solution of a petroleum fluid can occur when it is subjected to low temperatures. The solid phase - formed by high molecular wheight components - may cause serious operational problems that can even lead to an interruption of the mixture production. Hence, it is important to predict the way it happens for a mixture with known composition. The objective of the present work is to study these phenomena using a thermodynamic modeling, to provide a way of calculating the main characterizing properties for the equilibrium between the existing solid and liquid phases of a petroleum mixture. The properties of interest are the temperature at whieh the solid-phase ? named wax- preeipitates (W.P.T.), and the solid fraction that precipitates below this temperature. Comparing the caleulated values of these properties to the experimentally obtained ones, one can judge the precision of the adopted modeling. The use of accurate experimental techniques is then of fundamental importance in studies like the one developed in this work. Not only for obtaining the data to be compared to the calculated property values, but also the data used by the thermodynamic models. The maio experimental techniques used for obtaining all these data are presented and. discussed. The W.P.T. s of some mixtures used in this study were determined by viscometry and differential scanning calorimetry techniques. These mixtures are being considered due to operational problem swhich occurred in their production systems. A comparison between the calculated and the experimental results revealed the superiority of the model that assumes non-ideal behavior of both phases. The Regular Solution theory can be considerated useful for representing this non-ideality, which is expressed in terms of the activity coefficients for the components in both phases. The model predictive capacity could be improved by fitting to accurate solid fraction data at low temperatures. The experimental technique regarding this property determination presented in this work deserves coser attention, as much as others that could be identified for the same use

ASSUNTO(S)

engenharia do petroleo termodinamica

ACESSO AO ARTIGO

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