Method for the direct determination of physical properties of hydrocarbon products
First Claim
1. A method for preparing a blend of liquid hydrocarbon components and controlling at least one physical property of the blend, the method comprising the following steps:
- (a) determining with an IR spectrometer, an absorbance at each of a selected number of frequencies in a spectral range 16667 to 3840 cm-1 for each component starting from a defined base line,(b) determining for each component I and each physical property J, a spectral mixture index (SMI)JI by applying a correlation with measured absorbance values, wherein the correlation is determined experimentally by multivariate regression of a set of blends serving for calibration and is dependent upon the spectrometer used, the property selected and the frequencies used,(c) selecting one or more physical properties desired in the blend,(d) calculating for the selected property J of the blend the quantity of the components required to obtain such physical property by applying a linear expression;
space="preserve" listing-type="equation">J=f.sub.a ·
SMI.sup.J.sub.a +f.sub.b ·
SMI.sup.J.sub.b +f.sub.c ·
SMI.sup.J . . . +f.sub.o ·
SMI.sup.J.sub.o(
1) each term of which is a product of the spectral mixture index (SMIa . . . ) of the property J for a component (A . . . ) and a fraction by volume (fa . . . ) of this component, and(e) mixing the calculated quantities of the components to obtain the desired blend.
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Accused Products
Abstract
The properties of a liquid hydrocarbon blend are determined from the NIR (Near Infra Red) spectrum of the components of the blend. This is accomplished by: (a) determining with an IR spectrometer, the absorbance of the components of the blend at a certain number of frequencies in the spectral range 16667 to 3840 cm-1 starting from a defined base line, (b) determining for each component and each property, a spectral mixture index (SMI) by applying a correlation between the SMI and the absorbance values, and then (c) calculating the property (J) to be determined by applying a linear expression, J=fa SMIaJ +fs SMIbJ +fc SMIcJ + . . . fo SMIoJ where SMIJ.sub.(a, b, c . . . ) is the Spectral Mixture Index for property J for each component (a, b, c . . . ) and f.sub.(a, b, c . . . ) is the fraction by volume of that component in the final blend. The correlation in (b) is determined experimentally by multivariate regression, and is dependent upon the type of spectrometer used, the property to be determined, and the frequencies used.
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Citations
18 Claims
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1. A method for preparing a blend of liquid hydrocarbon components and controlling at least one physical property of the blend, the method comprising the following steps:
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(a) determining with an IR spectrometer, an absorbance at each of a selected number of frequencies in a spectral range 16667 to 3840 cm-1 for each component starting from a defined base line, (b) determining for each component I and each physical property J, a spectral mixture index (SMI)JI by applying a correlation with measured absorbance values, wherein the correlation is determined experimentally by multivariate regression of a set of blends serving for calibration and is dependent upon the spectrometer used, the property selected and the frequencies used, (c) selecting one or more physical properties desired in the blend, (d) calculating for the selected property J of the blend the quantity of the components required to obtain such physical property by applying a linear expression;
space="preserve" listing-type="equation">J=f.sub.a ·
SMI.sup.J.sub.a +f.sub.b ·
SMI.sup.J.sub.b +f.sub.c ·
SMI.sup.J . . . +f.sub.o ·
SMI.sup.J.sub.o(
1)each term of which is a product of the spectral mixture index (SMIa . . . ) of the property J for a component (A . . . ) and a fraction by volume (fa . . . ) of this component, and (e) mixing the calculated quantities of the components to obtain the desired blend. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification