Étude de la propension à former des suies de divers carburants modèles du kérosène et de mélanges contenant des composés oxygénés

Abstract

Jet fuels (e.g., Jet-A and Jet-A1) which are widely used for aviation also raise a growing interest for usage in Diesel engines and generators. The combustion of these fuels, however, generates soot particles that have adverse impacts on the environment and health. To meet the increasingly stringent regulations aimed at limiting such emission of particulate pollutants, we must improve our understanding of the soot formation mechanisms while also identifying lowsooting additives to be blended with petroleum fuels. Although numerous fundamental studies have been carried out to elucidate the propensity to soot of individual hydrocarbons, the complexity of jet fuels, which comprise hundreds of compounds, prevents the carrying out of proper simulations aimed at predicting their combustion behavior. To overcome this issue, the formulation of surrogates composed of a relatively small number of pure hydrocarbons is of high interest as such model fuels enable conducting the well controlled and reproducible experiments required to develop reaction mechanisms which account for the combustion of complex fuels. Within this context, the present work aims at identifying a convenient surrogate which mimics the sooting tendency of Jet-A1 with the view to blend it with various oxygenated fuels to evaluate their respective soot suppressing effect. To do so, 6 formulations of model fuels have been tested. Their propensity to soot has been characterized by means of the oxygenextended sooting index (OESI) as a sooting index. The smoke point (SP) which is the experimental parameter measured to compute the OESI has been assessed by implementing two different automated smoke point measurement approaches from the literature whose respective performance has been compared. In terms of result, a mixture composed of ndodecane, isocetane, 1,3,5-trimethylbenzene and n-propylbenzene has been identified as being the most suited to reproduce the sooting tendency of Jet-A1. This surrogate has therefore been selected to be blended with up to 40 vol% of various alcohols, esters and furans including ethanol, butanol, butyl butanoate, methyl octanoate, furfuryl alcohol, tetrahydrofurfuryl alcohol and furfural. The OESI of these mixtures have been measured so leading to conclude that the soot suppressing effects of the tested additives was strongly related to both their molecular structure and to the nature of the oxygenated functional group. The results gathered within this experimental work have finally been simulated by means of a recently developed group increment model which allowed accurately reproducing experimentally monitored results regardless of the tested fuels.

Date	22 Apr 2022
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Romain Lemaire (Supervisor) & Patrice Seers (Co-supervisor)