Michel Dorbon

Nitrogen compounds in light cycle oils: identification and consequences of ageing

Abstract Basic and non-basic nitrogen compounds were selectively extracted from different light cycle oils (LCOs). The isolated fractions were analysed by nitrogen selective detector gas chromatography and by gas chromatography/mass spectrometry. The basic compounds are aniline and alkyl derivatives from C 1 - to C 4 - anilines. The non-basic compounds are indole, C 1 - to C 4 - alkylindoles, carbazole and C 1 - to C 3 -alkylcarbazoles. In the four different LCOs that we have investigated, the distributions of the nitrogen compounds are very similar and no other nitrogen compounds were found. It has been shown that after ageing, the distribution of nitrogen compounds is different: the evolution of indoles is more important than the evolution of anilines and carbazoles.

On-line chromatographic analyser for determining the composition and octane number of reforming process effluents

Abstract An on-line analyser for reforming process effluents was developed from a commercial chromatograph and a computer. A temperature-programmed capillary column is used with software to make a detailed analysis (by automatic identification on the chromatogram) and to determine different physical properties (specific gravity, molecular weight, research and motor octane numbers, etc.).

Simulated distillation of distillates on capillary columns: influence of the polarity of the stationary phase

Abstract Gas chromatographic simulated distillation gives the boiling range of petroleum products. It has been shown that with capillary columns (as with packed columns), the simulated distillation results of aromatic samples change with the polarity of the stationary phase. Three columns of different politary, sufficiently thermostable to elute samples having boiling points as high as 600°C were tested. It has been shown that the more suitable column for simulated distillation of vacuum distillates is one with medium polarity.

IDENTIFICATION OF NITROGEN COMPOUNDS AND THEIR EVOLUTIONDURINGAGEING NABSENCE ANDPRESENCE OF ADDITIVES EFFICIENCYOFHYDROTREATMENT

Abstract As established by several previous works, nitrogen compounds play a prominent role in the evolution of middle distillates containing cracked components, particularly regarding sediment formation and color evolution. In a first part, this paper describes and compares stability properties of fuel blends using both an accelerated ageing method at 120°C (248°F ) and long term storage methods at 43°C(110°F) -ASTM 0 4625 - and at ambient temperature. Effectiveness of stabilizing additives is also evaluated. In mixtures containing LCOs, insoluble products are formed progressively during ageings, more or less rapidly according to the chemical constitution of the mixtures. Then, it reports the complete identification of nitrogen compounds using gas chromatography equipped with a selective nitrogen detector and mass spectrometry showing that in light cycle oils, alkyl indoles and carbazoles are the main families. Evolution of these compounds was followed kinetically during ageings in absence and presence o...

On-line chromatography with capillary columns and temperature programming : Determination of traces of 2-butenes in 1-butene and analysis of a reformate

Two examples of automatic on-line chromatographic analysis with capillary columns and temperature programming are presented. The first is the detailed analysis of the effluent from a reforming unit. The sample is a C4C11 cut, mainly aromatic, which contains more than 200 compounds. It is shown that with automatic injection onto a capillary column, the resolution is as good as with manual syringe injection. Moreover, no discrimination between light and heavy compounds is observed. The second is the determination of ethylene, 1-butene (ca. 80%), traces of 2-butenes (less than 50 ppm), iso- and n-butane and C6 olefins. This analysis was effected on a chromatograph equipped with two non-polar capillary columns and two detectors with different sensitivity ranges. The sample is injected simultaneously onto the two columns. On one detector the traces are analysed but the peak of the main component is saturated; on the other detector, the main component is analysed. The reproducibility of the retention times was checked, in both examples, in a 1-month test with automatic on-line injection.