Thesis of Doha Kdouh

Defense of thesis Doha Kdouh -  laboratory PC2A

Abstract : 

In the face of growing environmental challenges and depleting fossil fuel reserves, the shift toward sustainable energy solutions has become more than a goal, it is an imperative for the future of our planet. The continued dependence on fossil fuels has led to environmental and public health challenges, driving the search for cleaner and more sustainable alternatives. Among these, biofuels have emerged as a promising solution, particularly when blended with diesel fuels to mitigate emissions and reduce environmental impact. However, research on the combined use of ethanol and iso-butanol in diesel fuel combustion remains limited, especially in atmospheric laminar premixed flames. To bridge this gap, this study explores the effects of blending ethanol and iso-butanol with toluene reference fuel (TRF), a surrogate composed of toluene, iso-octane, and n-heptane that closely replicates the physical and chemical characteristics of diesel.
The study investigates eight distinct fuel blends under atmospheric premixed laminar flame conditions, analyzing TRF at two equivalence ratios (1.72 and 1.82), TRF-E (TRF blended with ethanol) at four equivalence ratios (1.72, 1.82, 1.92, and 2.02), and TRF-B (TRF blended with iso-butanol) at two equivalence ratios (1.72 and 1.82). When biofuels are introduced into TRF mixtures, they significantly alter combustion chemistry, influencing the formation of oxygenated and non-oxygenated hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and soot. This study takes a comprehensive approach to pollutant characterization, systematically analyzing a broad spectrum of combustion byproducts, from small hydrocarbons to larger oxygenated compounds, PAHs, and ultimately, soot.
To achieve a detailed and quantitative understanding of these processes, multiple techniques are employed. Gas chromatography (GC), laser-induced fluorescence (LIF-NO), laser induced incandescence (LII) and thermocouple-based temperature measurements. These techniques offer an in-depth exploration of how biofuel blends influence combustion chemistry and pollutant formation. The findings of this study underscore the delicate balance between fuel composition, combustion efficiency, and emissions control. While biofuels show great potential in reducing pollutant emissions, they also introduce new chemical pathways that impact pollutant formation. Notably, the addition of ethanol and iso-butanol to TRF mixtures remains a relatively unexplored area in these specific flame conditions, making this research particularly valuable for advancing cleaner fuel technologies.

Keywords : combustion,oxygenated biofuels,laminar flames,PAHs,soot