13.07.2015 Views

Caracterização de Petróleo por Espectroscopia no Infravermelho ...

Caracterização de Petróleo por Espectroscopia no Infravermelho ...

Caracterização de Petróleo por Espectroscopia no Infravermelho ...

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ABSTRACTTITLE: CHARACTERIZATION OF PETROLEUM BY NEAR INFRAREDSPECTROSCOPYAuthor: Aerenton Ferreira Bue<strong>no</strong>Supervisor: Prof. Dr. Célio PasquiniThis work aims the <strong>de</strong>velopment of an analytical method for cru<strong>de</strong> oilcharacterization using Near Infrared Spectroscopy (NIR) and multivariate calibrationtechniques. Two instruments were evaluated for the collection of NIR spectra, usingtransflectance probe and transmittance cell. The statistical techniques used forcalibration were: Partial Least Squares (PLS) and Artificial Neural Networks (ANN),using three different spectral regions. Calibrations were <strong>de</strong>veloped for two essentialproperties to cru<strong>de</strong> oil characterization: specific gravity (API gravity) and true boilingpoint (TBP) curve. For this study, samples of cru<strong>de</strong> oil processed at PetrobrasHenrique Lage refinery and other national and foreign petroleum samples wereanalyzed. The precision of the method was <strong>de</strong>termined through a repeatability test.The performance of the calibrations was evaluated by means of an externalvalidation, followed by a statistical test to compare the results. The best results wereobtained trough the use of spectra collected with the 0.5 mm pathlength calciumfluori<strong>de</strong> transmittance cell within the 5,000 to 4,000 cm -1 (around 2,000 to 2,500 nm)spectral range and calibration by PLS. The validation, through an in<strong>de</strong>pen<strong>de</strong>nt set ofsamples, <strong>de</strong>livered satisfactory results, better than the results obtained by a processsimulator used at the refinery.xiii

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