Resumen

QUINTERO, Karla; LOPEZ, Liliana  y  DE LIMA, Lola. Fourier Transforms Infrared Spectroscopy - Attenuated Total Reflectance (FTIR / ATR) applied to characterization of crude and its relationship to API gravity. Rev. Fac. Ing. UCV [online]. 2014, vol.29, n.2, pp.93-102. ISSN 0798-4065.

Ten Venezuelan crudes were characterized by FTIR-ATR, in order to determine variations in composition, in terms of structures (aliphatic, aromatic) and functional groups (carbonyl, sulphoxide); and their relationship with the API gravity. From these analyses, aliphatic, ramification, long chain, aromaticity, ring aromatic, substitution 1, substitution 2, carbonyl, and sulphoxide indices were calculated. The results indicated that by using the FTIR-ATR, the composition indices can be obtained with coefficients of variation lower than 10%. The lower the intensity and resolution of the band, the greater the coefficient of variation obtained. The relationship with the API gravity can be described by chain length, aromaticity, carbonyl and substitution 1 indices. Additionally, the ratio chain length/aromaticity shows a linear correlation with the API gravity, and we propose its use to estimate crudes’ API gravity.

Palabras clave : Crude oils; FTIR-ATR; API gravity; Compositions.