Interests/objectives

• Ecological assessment / PPA
• Physical-chemical properties of the compound in the gas phase
• RON an MON calculation of condensed gasolines
• Analysis and performances of Optimgaz system

Methods used

Gas Phase Chromatography Mass Spectrometry

Results / Conclusions

• Compounds found in the gaz phase or the automoble gazolineComposé(quantitative ans qualitative)
• Calculeted macroscopic properties
• Rate of abatement of hydrocarbons in gasoline
• Chromatograms of gasoline vapours
  

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Interests/objectives

• Performance study of Optimgaz System in the condensation of VOC in gasoline (SP 98 and SP 95).
• To draw up an ecological assessment of the service station by calculating the rate of abatement of the VOC at the moment of the use of the Optimgaz system.
• To calculated the RON and the MON (octane number) of condensates given out of the tank.
• Integration of optimgaz system in the PPA ( Plan of Protection of the Atmosphere)

Recommended methods of analysis :

• Gas Chromatography (qunatitative analysis of fuels),

• Mass spectrometry qualitative analysis) et

• DT/GC/MS

Physical-chemical types of selected analysis being methods known as sure and reliable, used largely in refineries and analysis laboratories.

Gas phase chromatography

Principle.

Gas chromatography (CPG) is, like all the techniques of chromatography, a technique which makes it possible to separate from the molecules of a mixture possibly very complex of very diverse nature and volatility.It applies mainly to the compounds gas or likely to be vaporized by heating without decomposition in the injector.

The mixture to be analysed is vaporized in the entry of a column, with contains a activeted substance solid or liquid called stationary phase, then it is tranported through this one uing a carrying gas (or carrier gas).The column, placed in a thermostated furnace, is a tube of weak section rolled up on itself and containing the stationary phase. A great choice of detectors allows the analysis

selectiv and sometimes the identification of very complex mixtures.

The various molecules of the mixture will be separated and leave the column the ones after the thers aftre a certain lapse of time wich is a function of the affinity of the stationary phase withe these molecules.

Intrumentation.

In the most traditional configuration, the chromatograph is equipped with a diving injector, a capillary tube and a ionization flame detector. The data are treated by an information processing system. Fig.1 : Diagram of a GPC apparatus, provided with a ionization flame detector -->

Mass spectrometry

Principle 

The mas spectrometry is a chemical technique of analysis making it possible to detect and identify molecules of interest by measurement of their monoisotopic mass. Moreover, the mass spectrometry allows to caracterize the chemical structure of the molecules by splitting up them. its principle lies in separation in gas phase of molecules charged (ions) according to their masse/charge report ratio (m/z).

Fig. 2 - Diagram of the structure of a mass spectrometer: example of a mass spectrometer with a magnetic sector associated with a source of ionization of electronic impact.

The system of thermic desorption /chromatography in phase gas/mass spectrometry.

The GPC/MS apparatus is used to determine the presence and the concentration of volatile organic compounds in gas samples.the majority of the VOV starting from C5 (pentane) until C16 (hexadecane) can be identified and quantified with a precision of the order of the ppbv. The samples are collected on adsorbent tubs on multiple levels. They are them desorbed on the thermal desorber connecte to the gas phase chromatograph/ mas spectrometer (GC/MS).The chemical compound are separated by high resolution capillary chromatography.The contents of detected and identified VOC are quantified by using toluene like external standard. The selected target compounds are identified and their contents quantified using indvidual standards.