Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Chemical analysis
Reexamination Certificate
1999-02-10
2001-08-14
Shah, Kamini (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Chemical analysis
C702S024000, C702S030000, C436S161000, C436S174000
Reexamination Certificate
active
06275775
ABSTRACT:
The invention relates to an analytical method that makes it possible to quickly predict a set of global physico-chemical properties and/or a temperature profile on complex petroleum products by using a combination of chromatography coupled to specific detectors.
BACKGROUND OF THE INVENTION
The technological background is illustrated by Patents U.S. Pat. Nos. 5,699,269, 4,971,915 and by the publication by SEINSCHEK et al. “Anwendung Der PLS-Regressions Methode Auf Daten der Gaschromatographie Und Der Ir-Spektroskopie [Use of PLS Regression Methods on Gas-Chromatography and IR-Spectroscopy Data] Quality Control of Jet Fuels—PLS Regression Analysis of Gas-Chromatographic and Ir-Spectroscopic Data,” Erdoel Erdgas Kohle, Vol. 112, No. 6, June 1996, pages 261-263 XP000641535).
Traditionally, the analytical methods that relate to determining petroleum properties in hydrocarbons take a long time to carry out and are thus very time-consuming. Petroleum products consist of thousands of compounds. These products are thus generally identified and classified based on some of the properties, such as, for example: the range of distillation, density, and the cetane number.
Gas chromatography has been used to predict petroleum properties in gasoline-type petroleum products. Crawford and Hellmuth, Fuel, 1990, 69, 443-447, describe a chromatographic analysis that is able to predict the octane numbers of various effluents that come from the refinery, by application of mathematical models that are based on the statistical technique of principal component regression (PCR). Japanese Patent JP 03-100463 relates to a method that makes it possible to predict the cetane number from a specific analysis by coupling gas chromatography to mass spectrometry. The predicted cetane number is calculated by multilinear regression from the intensities of the selective ions.
These methods are therefore able to determine a global property of a product that contains hydrocarbon, but they are not suitable for providing data on this property as a function of the boiling points of the components of the product.
SUMMARY OF THE INVENTION
Currently, it would be advantageous, and this is an object of the invention, to have an analytical method that is able to predict from various analytical data a set of petroleum properties (or determinations) that are both global and reflect a distillation profile. For this purpose, the techniques of coupling chromatography to specific detectors are the most promising avenues.
These coupling techniques can be gas chromatography coupled either to mass spectrometry or to a flame ionization detector or to specific detectors of sulfur or nitrogen. The coupling of gas chromatography and an atomic emission detector has been preferred to these techniques because of the ease of implementation of this approach, which makes it possible to output the value of at least one element that is selected from the group of carbon, hydrogen, sulfur, and nitrogen, and preferably hydrogen or carbon, as a function of the temperature profile.
Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.
The invention relates to an analytical method that is able to predict a set of data that consist of global petroleum properties and/or a boiling point profile of petroleum products, from correlative mathematical models.
For this purpose, it is possible:
a) to define a set of petroleum properties and characterizations that can be predicted from analyses that are obtained by coupling;
b) to select the largest possible set of reference petroleum samples that constitute the calibration base, on which will be determined, according to conventional analytical methods, the various petroleum properties and determinations which will be predicted from the results of the coupling;
c) to follow the following analytical approach:
(1) to analyze each of the reference petroleum samples according to the conventional analytical methods that are known to one skilled in the art. The analytical results for each of the determinations will constitute a block Y of, for example, the calculation matrix for producing various correlative models;
(2) to inject the standard products in order to calibrate the various analytical channels of the coupling device under dynamic analysis conditions (calibration of the responses of carbon, hydrogen, sulfur, and nitrogen);
(3) to inject a known n-alkane mixture under the defined analytical conditions in order to determine the relation that links the retention time of these n-alkanes to their boiling points,
(4) to inject each of the reference petroleum samples that constitute the calibration base under the same analytical conditions by recording the signals of different channels, with those relating to carbon and hydrogen being preferred,
(5) to process the signals of different channels;
(6) to create a base of results that come from processing signals of various analytical channels (%C, %H, %S, %N, . . . , boiling point) that would constitute a block X of, for example, the correlative matrix;
(7) to analyze the various analytical data according to the various multivaried methods of analysis such as partial least square regression, principal component regression, the topological approach, neural nets, to determine the different coefficients of the correlative models.
(d) for the treatment of an unknown petroleum fraction, to follow the procedure of c(2) to c(3) and to inject the sample under the same conditions as c(4), to apply steps c(5) to c(6),
(e) to multiply the matrix by the coefficients of the models that are obtained in c(7) to predict the property or set of properties and/or desired determinations.
More specifically, the invention relates to a method for determining at least one physico-chemical property of a petroleum fraction, characterized in that:
a) at least one conventional analysis of a set of reference petroleum samples is carried out to determine the first set of data of a calculation matrix for developing a correlative model;
b) each reference petroleum sample is analyzed by chromatography, coupled to at least one detector under suitable conditions to determine the distribution of at least one element that is selected from the group that is formed by carbon, hydrogen, sulfur, and nitrogen as a function of the boiling points of the components of the sample, and a second set of data of the calculation matrix is drawn up;
c) the different coefficients of the correlative model are determined from the first and second sets of data according to multivaried methods of analysis;
d) chromatographic analysis of said petroleum fraction is done under the same conditions as those of step (b) to determine the distribution of at least one element of the carbon, hydrogen, sulfur, and nitrogen group as a function of the boiling points, and a third set of data relating to the petroleum fraction is drawn up;
e) the third set of data of step (d) is multiplied by the different coefficients of the correlative model; and
f) the physico-chemical property that is derived from the petroleum fraction is determined as a function of the boiling points of its components.
The coupling of gas chromatography/atomic emission detector (GC-AED) can be used advantageously for predicting a set of properties as a function of the temperature profile, such as:
physico-chemical characteristics of the product; refraction number, density
the elementary composition of the distillation profile
the simulated distillation curve of the product (%(m/m)=f(T° C.))
cold properties (pour point, cloud point, for example);
data relating to the concentrations of different radicals and their distribution as a function of the boiling point of the product;
the aniline point
the smoke point,
the percentage % (m/m) of aromatic carbon Ca;
the percentage % (m/m) of paraffinic carbon Cp;
the percentage % (m/m) of naphthenic carbon Cn;
the cetane number.
All of these determinations are made within a relatively short time (for example
Baco Franck
Quignard Alain
Szymanski Raymond
Bui Bryan
Institut Francais du Pe'trole
Millen White Zelano & Branigan
Shah Kamini
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