MCS6 Ajaccio, Corsica, France, June 7-11, 2009 Simplified Kinetic Mechanism of Ethyl Acetate Oxidation for HCCI Engines Francesco Contino * , V´ eronique Dias ** and Herv´ e Jeanmart * francesco.contino@uclouvain.be * Universit´ e catholique de Louvain, Mechanical Engineering Department, TERM - Place du levant, 2 - 1348 Louvain-la-Neuve - Belgium ** Universit´ e catholique de Louvain, Department of Chemistry, CSTR - Place L. Pasteur, 1 - 1348 Louvain-la-Neuve - Belgium Abstract Homogeneous Charge Compression Ignition (HCCI) is a combustion mode which virtually allows any kind of combustible liquids to be used in internal combustion engines. The pro- duction of biofuel could take advantage of this characteristic by driving the processes towards less refined fuels and so less energy-consumming operations. In particular, the products of the acidogenic fermentation will be discussed here. This process produces organic volatile acids which can be combined partly with ethanol (produced in the first step of the acidogenesis) and partly with glycerol (by-product of the biodiesel industry) to obtain a large range of esters. In this work, we have developed a kinetic mechanism for ethyl acetate (simplest fuel obtained in this route) in HCCI conditions. This paper describes the method used to simplify the mech- anism and then compares the simulated results with those obtained for the iso-octane and the ethanol. The kinetic mechanism includes 45 chemical species and 215 elementary reactions. CFD simulations show that ethyl acetate is very similar to iso-octane and ethanol. However, ethyl acetate shows a small difference in the low temperature chemistry. Introduction Biofuels production is restrained by the specific fuel characteristics required for spark and compression ignition engines. Therefore, a great part of the biomass energy content is lost in the successive steps of the biomass conversion [1]. Homogeneous Charge Compression Ignition (HCCI) combustion mode not only offers a great potential of efficiency improvement and emission reduction (i.e. NOx and soot) [2–8] but many works have also reported the multi-fuels capability of HCCI engines and have identified the impact of various fuel parameters on the running zone and on the control of the engine [9–12]. As HCCI extends the range of compatible fuels for internal combustion engines, it gives an opportunity to develop more simple and more efficient bioconversion processes. In particular, products resulting from acidogenic fermentation will be further discussed here. Acidogenic fermentation is traditionally considered to decrease negative ecological effects of polluting compounds. This process can be extended to low-value biomass wastes to improve their conversion into useful organic compounds. Acidogenic fermentation which produces volatile organic acids (including acetic, propionic, butyric and lactic acids) has three main advantages compared to ethanol fermentation: source diversification, efficiency and easy im- plementation. Indeed, it can use a wide range of fermentable organics substrates poorly or not treated (e.g. organic waste) and not only sugar. Acidogenic bacteria also have hydrolysis ca- pacity while yeast does not which means much less treatment to hydrolyze biomass. Finally, acidogenic fermentation does not require a germ free environment [13, 14].