Chemistry: analytical and immunological testing – Optical result – Including reagent preparation
Reexamination Certificate
1999-12-16
2002-09-17
Warden, Jill (Department: 1743)
Chemistry: analytical and immunological testing
Optical result
Including reagent preparation
C436S056000, C436S139000, C436S164000
Reexamination Certificate
active
06451615
ABSTRACT:
This invention concerns a new colored indicator that makes it possible to quantitatively measure the different hydrocarbon families present in a mixture and, in particular, in a gasoline for internal combustion engines with spark ignition, or in a jet propulsion fuel, by the technique using selective retention of these different molecule families on an absorbent carrier. The invention also concerns a procedure for obtaining this new colored indicator and its uses.
STATE OF THE ART
It is known that a fuel intended to supply an internal combustion engine with spark ignition is generally made up of different hydrocarbon families, such as hydrocarbons called “saturated,” containing simple bonds between the carbon atoms, such as molecules of the paraffin or naphthene type, as well as hydrocarbons called unsaturated, having benzene cycles, or at least a double bond between the carbon atoms, like molecules with aromatic or olefinic structure.
These different hydrocarbons present in automotive gasoline derive, essentially, from raw petroleum at the beginning of fuel manufacture where numerous chemical transformations take place in the different procedures most often used in a petroleum refinery, for manufacturing of these fuels. The saturated hydrocarbons contained in a fuel make it possible to improve, in a non-limiting manner:
the combustion properties in the cylinders;
the hydrogen/carbon ratio for increasing the calorific power of the fuel;
the stability of the fuel at high temperatures; those such as aromatic hydrocarbons and certain types of olefins promote the increase of:
the octane index to prevent uncontrolled auto-ignition of the fuel in the cylinders;
the density, to improve the engine yield while reducing its consumption.
It is also known that, in view of the problems connected with the environment and particularly those posed by emissions from different sources of fossil fuel in the cities, the regulations already in force, and those that are certainly to come, better control of the quantities of these hydrocarbon families introduced into gasoline is required and, in particular, the molecules that are liable to be harmful to air quality and thus to the health of consumers.
Several analytical methods are available to qualitatively and/or quantitatively check the distribution of the molecule families present in a hydrocarbon mixture, for example:
mass spectrometry using the ASTM D2789 method for measurement of aromatic compounds, for example;
gas chromatography and the ASTM D5443 method that make it possible to quantitatively determine paraffins, naphthenes, as well as aromatic molecules;
silica gel chromatography, in application of the ASTM D1319 (or ISO 3837) method for determination of aromatic, olefinic and saturated hydrocarbons.
These different methods make it possible to measure the amount of one or several components present in a hydrocarbon mixture and, in particular, gasoline for internal combustion engines. They differ in their precision, measuring time and also in the complexity of their usage, requiring a mass spectrometer or a simple chromatography column.
Among these methods, the one most used today, the simplest, the least costly and above all the only one currently specified at the international level is silica gel chromatography, conforming to the ASTM D1319 method. This method, called “FIA” which stands for “Fluorescent Indicator Absorption,” was standardized in 1954, and makes it possible to detect and measure the quantities of aromatic molecules contained in a gasoline in the range of 5% to 99% by volume, of olefinic between 0.3% and 55% by volume and of all the saturated hydrocarbons between 1% and 95% by volume.
Today, this analytical technique has been maintained in the scope of revising the NF EN228 method, as the reference analysis method in future specifications for internal combustion engine gasoline, in preparation for the year 2000 and relating most especially to the quantitative determination of olefins and aromatic hydrocarbons present in fuels.
The FIA method is based on the principle of liquid phase chromatography, a technique according to which the gasoline or the jet propulsion fuel is eluted with a desorbing alcohol (isopropanol, for example) on a column filled with silica. Separation of the components is shown because of the use of a colored indicator, made up mainly of yellow, blue and red colorings, specific to the hydrocarbon families, which migrate selectively in the column depending on the nature of these hydrocarbons, and of which the coloring can be detected, in particular for the yellow and blue, preferably under an ultraviolet light.
The zone of the column corresponding to saturated hydrocarbons is measured from the front of the elution located at the bottom of the column up to the level of the most intense yellow coloring, since the olefin zone ends at the level of the most intense blue coloring indicating the beginning of the aromatic zone, the latter being limited, above that, by a red ring.
The length of each zone thus identified on the column is directly proportional to the volume of the molecules of the saturated, olefin or aromatic type present in the fuel, the sum of these three zones representing 100% of the hydrocarbons present in the fuel.
One problem posed by this standardized analytical method is that it becomes falsified and leads to erroneous measurements when the fuel being analyzed contains certain oxygen products, as is becoming more and more frequent in fuels that are now on the market.
In fact, it is known, that in order to adjust the fuel octane index, refiners introduce compounds called oxygenated compounds into them, in the form of alcohols, such as methanol or ethanol, in the form of ethers, like methyl-tert-butylether (MTBE), ethyl-tert-butylether (ETBE) or even di-isopropyl ether (DIPE) or tert-amylmethylether (TAME) or mixtures of these oxygenated compounds which prevent the risk of pollution in vehicle exhaust due to organic lead derivatives previously used and for which restrictions against usage are planned in Europe starting in the year 2000, unless there are exceptions which could be agreed upon in certain countries.
The ASTM D1319 method, which was revised twice in 1995, indicates that at the concentrations normally used in commercial gasoline and which usually vary between 5% and 20% by volume, these oxygenated compounds introduced into the gasoline do not interfere with the determination of the hydrocarbon families. These oxygenated compounds are not detected by the FIA method since, with elution with desorbing alcohol, there would be no influence on the distribution of the hydrocarbons in the chromatography column and thus on their measurement.
DETAILED DESCRIPTION OF THE INVENTION
In the course of this work by the FIA method of checking the composition of fuels for internal combustion engines with spark ignition, the Applicant has given evidence, using the tests which will be explained in the following description, that an analysis carried out by the FIA method on a fuel containing oxygenated products, particularly an ether, such as ETBE, leads to considerable deviations in the amounts of hydrocarbons previously obtained in the same fuel without oxygenated products when the ASTM D1319 method is strictly applied.
Thus it appears that the presence of the ETBE and of other oxygenated compounds such as TAME and DIPE, alone or in a mixture with hydrocarbons in the gasoline, is responsible for a systematic error in the measurement of amounts of certain constituents of a gasoline by the FIA method. When the method ASTM D1319 is strictly applied, the rate of aromatic hydrocarbons is overestimated since the amount of saturated hydrocarbons is underestimated.
More precisely, the Applicant has established that the oxygenated products present in the mixtures of hydrocarbons to be analyzed by the FIA method and of which the molecule comprises at least 6 carbon atoms act like aromatic hydrocarbon in the course of elution and explain the deviations recorded by this analysis, in particular when the mixtur
Borg Francoise
Lefebvre Dominique
Seyfried Luc
Gakh Yelena
Total Raffinage Distribution S. A.
Warden Jill
LandOfFree
Colored indicator to measure the distribution of the... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Colored indicator to measure the distribution of the..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Colored indicator to measure the distribution of the... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2882738