Insights into the role of fuel structure and blending in soot formation for C1–C4 hydrocarbon flames

Abstract

Soot, a carbonaceous particle formed during the incomplete combustion of hydrocarbon fuels, not only reduces combustion efficiency but also poses significant risks to human health and the atmospheric environment. The formation of soot is a complex process involving physico-chemical transformations, and variations in fuel structure and fuel blending significantly impact soot production. Therefore, understanding the mechanisms of soot formation in C₁–C₄ hydrocarbon fuel flames and the associated influencing factors is crucial for effective soot emission control. This paper systematically reviews the primary mechanisms of soot formation in hydrocarbon flames. It further summarizes the research progress on soot formation during the combustion of C₁–C₄ hydrocarbons, with particular focus on how changes in fuel structure and blending affect soot formation. The influence of carbon chain length and saturation on soot formation is discussed, as well as the synergistic effects of blended fuel combustion. Lastly, the impact of non-hydrocarbon additives (e.g., CO, NH₃/H₂, CO₂/H₂O) on soot formation is examined, highlighting the chemical coupling between hydrocarbon and non-hydrocarbon components. These findings provide valuable insights for understanding soot formation, optimizing fuel properties, mitigating soot emissions, and advancing cleaner combustion technologies.