| abstract |
A sample of a hydrocarbon oil containing asphaltenes is chromatographically analyzed by forming a mixture of the oil with a weak solvent. The mixture is passed in contact with a column of a stationary phase of fine solid particles of fully functionalized material, followed by a weak solvent. The solvent, after recovery from the column, is analyzed for aromatics by UV-absorption of UV radiation in the range 200 to 500 nm. The absorbance of the UV light by the irradiated eluents across the UV wavelength range is monitored and the integral of absorbance is derived as a function of photon energy across the wavelength range. The magnitude of the derived integral in at least one time interval corresponding with aromatics in the eluent from the stationary phase is measured as an indication of the level of aromatics in the oil sample. The weak solvent may be followed by a strong solvent which, in turn, may be followed by a strong solvent which is modified by the addition of a hydrogen bonding solvent. The solvents are analyzed for saturates, aromatics, polar compounds and any asphaltenic materials by the combination of the UV-absorption measurement and a mass sensitive measurement which measures the combined level of the saturates, aromatics, polars and any asphaltenic compounds present. Equipment to perform the foregoing analysis is also described. The analysis can be used for evaluation of an oil and/or for on-line regulation of an oil refining process. |