Soot formation

Chemical Kinetic Modeling Study of the Effects of Oxygenated Hydrocarbons on Soot Emissions from Diesel Engines

“…Therefore these incompletely oxidized species such as CO, H 2 and small, intermediate hydrocarbon species including acetylene, ethene, propene and others then react to produce soot [17][18][19] which is later consumed in a diffusion flame environment 19 farther downstream of the ignition region. The same unsaturated hydrocarbon species have been identified as major contributors to soot production in both diesel engines and laboratory flames [21][22][23][24][25][26][27][28][29][30][31][32] .…”

“…We rely largely on the soot modeling work of Frenklach 22,23 , which is based in turn on many careful and thorough experimental soot evolution studies, including particularly [24][25][26][27][28][29][30] . The overall picture of soot kinetics that emerges from these studies is that small aromatic and polycyclic aromatic hydrocarbons (PAH) such as benzene, toluene, naphthalene, pyrene and styrene are produced from small unsaturated hydrocarbons such as acetylene, ethene, propene, allene, propyne, and cyclopentadiene, as well as resonantly stabilized hydrocarbon radical species such as propargyl, allyl, and cyclopentadienyl 31 .…”

Numerical simulations of soot aggregation in premixed laminar flames

“…The mechanism for their growth has been investigated under many conditions and for a variety of chemical systems [18,26,27,8,13,6,3]. In most cases there is an initial phase of coalescent growth [11], where coagulation with small particles caused by high particle inception and rapid surface growth cause the particles to grow into near spherical "primary" particles. The coalescent regime is followed by particle aggregation, when the particles take on the form of fractal aggregates [15,14,20].…”

Chemical Additives for Maximizing Fuel Reactivity

“…The effect of additives on soot formation in flames has been studied extensively (for example, see the literature cited in Haynes and Wagner, 1981). In diffusion flames, the simple dilution of fuel by inert gases generally decreases the tendency to produce soot.…”

“…The most striking effects of additives are those exhibited by various metals {Haynes and Wagner, 1981), some of which are used commercially as smoke suppressants in liquid-fuel combustion (Ba is widely used as a diesel smoke suppressant and is added in the amount 0.5% by weight of the fuel). Alkali and alkaline earth metals, manganese, iron and other transition metals such as nickel, cobalt and copper can also reduce smoke.…”