الفهرس 
Cover EnglishOnly 14 pages are availabe for public view
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Abstract
The analysis of crude oil using laser Spectrochemical analytical techniques gives privilege compared to conventional techniques in terms of reducing the size of sample, fast measurements, high sensitivity, and possibility of in situ measurements. In this work a detailed study will be presented for the use of laser-induced fluorescence (LIF) and laser-induced breakdown spectroscopy (LIBS) as quick and simple spectrochemical analytical techniques to identify and characterize different grades of petroleum crude oil. The fluorescence radiation emitted from crude oil results from the interaction between the electromagnetic radiation and the existing aromatic compounds. Therefore the fluorescence spectra and their intensities are directly affected by the chemical composition and physical properties of the investigated oil samples. Important information pertaining to fluorescent structure might be lost with the use of a single excitation wavelength, but might be obtained with other excitation wavelengths and thus enhancing the technique capability of discrimination between different crude oil samples. For this reason, fluorescence spectra in the present work were obtained using four CW lasers’ wavelengths as excitation sources. Five dry crude oil samples with American Petroleum Institute (API) gravities between 18 and 44 were diluted to 50mg/l using chlorinated solvent. The excitation of the samples was performed using diode pumped solid state lasers (DPSS) emitting at 266nm, 405nm, 532nm and an Argon ion laser at 488nm. On the other hand laser induced breakdown spectroscopy (LIBS) technique has been used for direct measurement of atomic and ionic species in six dry crude oil samples. The technique has been performed using first harmonic of pulsed Nd –YAG laser source (l = 1064 nm). Atomic emission from laser-induced plasma was observed for characteristic elements and molecules in petroleum such as C, H, Si, Na, Ca, Mg, AL, Fe, Ti, Mo, C2 and CN for each sample, The intensities of the most intense and well resolved spectral lines for some elements such as Ca, Na, Fe, Mo, C2 and CN were measured at different wavelengths along the obtained spectra. The primary assessment of these elemental spectral lines was utilized to differentiate between the crude oils with API gravity correlation. The results showed the presence of a clear relation between the API values and the concentration of these elements for different samples.