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Accueil du site > Thèmes de recherche > Combustion & systèmes réactifs > 1.3 New fuels

1.3 New fuels

Because they are renewable, biofuels and synthetic fuels from bio-resources are attracting great interest as transportation fuels but also for energy production. They may be less polluting, sometimes more biodegradable, and could reduce net greenhouse gas emissions. However, their application in engines and other combustion devices requires combustion models and experimental databases for their burning under various conditions (lean combustion, high pressure, exhaust gas recirculation…). Several studies have been recently performed at ICARE on the kinetics of oxidation of oxygenated fuels, naphtenic hydrocarbons, and synthetic fuels (in cooperation with the Universities of Galway and Illinois-Chicago, and under a research contract PNIR-CAM1 with CNRS, PSA, TOTAL).

1.3.1 Combustion of hydrogen-enriched fuels, syngas, and biofuels
The optimisation of IGCC power plants (Integrated Gasification Combined Cycle) that produce electricity from combustion of syngas (CO/H2) in gas turbines necessitates many studies on the effect of fuel composition and dilution by carbon dioxide. A better understanding of the combustion kinetics of such fuels and of the effects of variation of their compositions is needed. Experimental and numerical flame structure studies have been performed at atmospheric pressure in order to specify the effect of CO2, H2 and H2O addition in CH4 and CO flames (ACL63). High pressure biogas (CH4/CO2) flames are currently studied. This work was completed with laminar syngas flames velocities measurements using the Particle Imaging Velocimetry (PIV) technique (ACTI60, ACTI62, see also below Groupe Thématique on Combustion Dynamics). The kinetics of combustion of hydrogen-enriched fuels was also studied through the PIE-CNRS HyTAG project and a contract with EDF. The kinetics of oxidation of fuel mixtures containing methane, syngas, CO2, and H2O were studied (ACL23, ACL45-47, ACL60-61). Further studies were performed through the ANR project TACOMA. The effect of fuel dilution by water vapour and interactions with SO2 were studied in a JSR and modelled.

1.3.2 Combustion of fatty acids methyl esters and biodiesel surrogates.
Fatty acids methyl esters are new components of Diesel fuels for which little was known until recently. ICARE published the first kinetic study of the oxidation of rapeseed oil methyl ester in a JSR (ACL16). The kinetic modelling was performed using several model fuels, showing that RME behaves very similarly to large alkanes under JSR oxidation conditions. In collaboration with the Universities of Toronto and Princeton, we studied the kinetics of oxidation of simple methyl esters to improve our knowledge of biodiesel combustion kinetics (ACL22, ACL30, ACL40, ACL43, ACL57). The kinetics of oxidation of ethyl esters was also investigated in collaboration with the University of Galway (ACL64). These studies were conducted through several research projects (Predit contract Biokin ; NSF International Research and Education in Engineering support with the University of Illinois-Chicago). Other chemical kinetic studies are currently performed for the oxidation of biodiesel through a research contract with Renault and a research project with ESA-MAP on Combustion Properties of Partially-Premixed Spray Systems.

1.3.3 Other oxygenated fuels : alcohols, ethers, and ketones
Ethanol accounts for over 90% of all biofuels production worldwide. However, mixing stability issues may appear with simple alcohols whereas larger alcohols would mix better with petrol-derived fuels due to their longer alkyl carbon chain. Therefore, the kinetics of oxidation of methanol, butanol isomers, 1-pentanol, and 1-hexanol were studied experimentally and modelled. Their mixtures with hydrocarbons and methyl esters were also investigated (ACL17, ACL55-56, ACL68, ACL70, ACL72). This research was partially performed in collaboration with PRISME-University of Orléans, the University of Toronto, and IFP. A collaboration with the University of Galway aimed at determining the laminar flame speeds of a series of oxygenated species and was supported by the ULYSSES program (ACL66). The kinetics of combustion of oxygenated gasoline additives, such as ETBE, has also been studied (ACL 52).

1.3.4. Synthetic fuels from coal, natural gas and biomass
Liquid fuels can be synthesized using an adapted Fischer-Tropsch process. We have studied the kinetics of oxidation of reformulated jet fuels in the project CALIN (supported by the Pôle de compétitivité Aerospace Valley). Experiments in a JSR and kinetic modelling were also performed within the ongoing FP7 European project Alfabird (ALternative Fuels And Biofuels for aIRcraft Development). These studies yielded a unique data base for the kinetics of reformulated jet fuels and are continuing.