Characterization by laser diagnostics of the sooting propensity of biomass-derived fuels intended to be used as environmentally-friendly substitutes to fossil fuels

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This program aims at improving the understanding of the sooting behavior of different biomass-derived fuels to support the development of cleaner energy carriers. Actually, soot is one of the major pollutants generated in combustion processes and one of the main contributors to anthropogenic aerosols. To limit its production with the view to meet actual and future regulations, source reduction remains a key option particularly considered by engine manufacturers. A thorough understanding of the physicochemical mechanisms involved in the formation of polycyclic aromatic hydrocarbons (PAHs) and soot is still required however (especially in the case of biofuels) to improve the predictive character of the computational codes used to design combustion devices. The purpose of the present program is therefore to provide insightful findings regarding the ability of different molecules to act as soot suppressors with the view to identify the must-have fuel properties necessary for the mid- to long-term commercialization of environmentally-friendly substitutes to petroleum-derived fuels. To do so, the present proposal which associates laboratory scale experiments and engine tests is composed of 3 main objectives summarized as follows: 1) Developing predictive sooting propensity indicators incorporating all the fuel molecular structural effects known to influence soot production. To do so, the Fuel Equivalent Sooting Index (FESI) of various biofuels (including furan isomers and some components of bio-oils derived from wood pyrolysis) will be measured. Obtained results will then be processed by means of a structural group additivity approach to propose an original set of predictive sooting propensity group contribution factors. 2) Developing Particulate Matter (PM) indexes suitable to predict engine particulate emissions. Based on measurements performed at the exhaust of direct injection Diesel and spark ignition engines, PM index formulations will be proposed integrating FESI values to represent the fuel molecular structure and fuel properties (including volatility factors) playing a role in the fuel/oxidizer mixture formation. 3) Developing adapted metrological tools necessary to achieve the above-mentioned objectives. Such a transverse task includes 1/ the development of a time resolved laser-induced incandescence/fluorescence (LII/LIF) technique for the simultaneous detection of soot and PAHs and 2/ contributions in the modeling of LII signals to infer information on soot physical properties through the implementation of advanced optimization algorithms. At the end of this program, innovative measurement and modeling tools will be proposed to explore some of the major issues needing to be addressed in order to develop cleaner fuels and combustion technologies that will benefit the Canadian energy production, aerospace and automotive industries among others.