Method for determining the octane indices of a complex mixture of fuels or the composition of such a mixture of fuels having an octane index determined by near-infrared spectrophotometric analysis of the constituents of the mixture

摘要

Method for determining the octane index of a fuel with a plurality of constituents, consisting in measuring by means of a near-infrared spectrophotometer the absorbence for a certain number of frequencies in the spectral band 12500-3840 cm-1 (0.8 to 2.6 microns) on the constituents or on arbitrary mixtures, and in determining for each constituent a certain spectral mixture index SMI by applying a correlative relationship with the measured absorbence values D@, this correlation being determined experimentally by multivariate regression, and in calculating the desired octane index by means of a linear relationship, in which each term 10 = Fa.SMIa + fb.SMIb + fc.SMIc ... + fO.SMIO is the product of the spectral mixture index (SMIa...) of a constituent (A...) with the volume fraction (fa...) of this constituent.