Real-time method for the identification and quantification of hydrocarbon pyrolysis products: Part I. Development and validation of the infra red technique

Grégory Abraham (1, 2) , Nicolas Gascoin (3) , Philippe Gillard (1) , Marc Bouchez (4)

1 PRISME - Laboratoire Pluridisciplinaire de Recherche en Ingénierie des Systèmes, Mécanique et Energétique
2 LEES - Laboratoire Énergétique Explosions Structures [1998-2007]
3 Univ. Orléans, PRISME, CE
4 MBDA-F - MBDA

Due to large heat load encountered in high speed flight (over Mach 5), the regenerative cooling of the engine leads to the study of the endothermic pyrolysis of the onboard hydrocarbon fuel, which acts as a coolant. However the control and regulation of such a technology implies to have a correct knowledge of the endothermic pyrolysis of the onboard hydrocarbon fuel, which motivates the development of a quantitative measuring method adapted to in-flight applications. A Fourier transform infra red spectrometer is used and a specific method has been developed to identify and to quantify the major hydrocarbon products of the pyrolysis. The technique is validated and tested at the outlet of the experimental pyrolysis process which operates under steady-state conditions from 823 K to 1023 K and up to 60 bar. Two mass flow rates (0.05 g s-1 and 0.1 g s-1) are studied with titanium reactor to determine the limits of validity and to improve the method. Several synthetic and jet fuels have been tested (heptane, decane, dodecane and two kerosenes). The quantities of five light hydrocarbons (methane, ethane, ethylene, propane, propylene) are determined. The method, based on classical least square processing, is validated with respect to gas chromatograph (and mass spectrometer) analysis notably. A minimum molar fraction of 5 mol.% can be obtained and the accuracy is better than 2 mol.%.

Mots clés: Classical least squares; Dodecane; Gas chromatographs; Heat loads; High speed flight; Hydrocarbon fuel; Hydrocarbon product; Hydrocarbon pyrolysis; Hydrocarbon pyrolysis products; Infra red; Light hydrocarbon; Mass flow rate; Measuring method; Molar fractions; Pyrolysis process; Regenerative cooling; Steady-state condition; Supercritical state; Chromatography; Ethane; Ethylene; Fourier transforms; Hydrocarbon refining; Mass spectrometers; Mass spectrometry; Methane; Organic compounds; Petroleum chemistry; Propane; Propylene; Pyrolysis; Synthetic fuels; Titanium; Least squares approximations

Domaines: Chimie analytique; Optique [physics.optics]

Grégory Abraham, Nicolas Gascoin, Philippe Gillard, Marc Bouchez. Real-time method for the identification and quantification of hydrocarbon pyrolysis products: Part I. Development and validation of the infra red technique. Journal of Analytical and Applied Pyrolysis, 2011, 91 (2), pp.368-376. ⟨10.1016/j.jaap.2011.03.014⟩. ⟨hal-00641587⟩