Shock-tube study on the influence of oxygenated co-reactants on ethylene decomposition under pyrolytic conditions

Impact of Methanol and Butanol on Soot Formation in Gasoline Surrogate Pyrolysis: A Shock-Tube Study

“…The simulated soot optical densities ( D 633 nm ) that were compared to the experimental results were calculated with the following by the equation below: , D 633 nm = f V , sim 6 π E false( m false) λ false[ normalC false] where E ( m ) is the dimensionless absorption function which is equal to 0.37 based on Agafonov et al and other previous work, , and λ = 633 nm is the wavelength of the HeNe laser.…”

“…where E(m) is the dimensionless absorption function which is equal to 0.37 based on Agafonov et al 28 and other previous work, 10,14 and λ = 633 nm is the wavelength of the HeNe laser.…”

“…We note a bimodal trend being different to typical "bell-shaped" curves, as observed in mix 1a or other base fuels like benzene or ethylene. 10,14 Soot particles are formed at a very wide temperature range, from 1500 to almost 3000 K, and two peak values of optical density are observed, one at ∼1800 K (D 633 nm,0.4 ms ≈ 18.4 m 2 /mol) and a second one at ∼2500 K (D 633 nm,0.4 ms ≈ 26.5 m 2 /mol). The simulations agree qualitatively well with the experimental results, matching with the experimental temperature range of soot formation and also predicting the formation of dual peak well, even though the second peak is shifted toward lower temperatures (2300 K).…”

“…Recently, Nativel et al , conducted studies dealing with the influence of oxygenated hydrocarbons on soot formation during the pyrolysis of soot precursors such as benzene and ethylene (C 2 H 4 ). Therein, shock-tube experiments were conducted and soot particle formation was monitored behind reflected shock waves by performing laser-extinction measurements.…”

“…Only the addition of CH 3 OH to C 2 H 4 did not alter the extent of soot formation. Nativel et al , discussed how the release of small radicals such as H and CH 3 from thermal decomposition of oxygenates promotes soot formation when C 2 H 4 is used as precursor but seems to slightly reduce the formation of larger PAH species when C 6 H 6 is applied as a precursor. Along with experimental results from other studies, these two opposite results from Nativel et al , also demonstrate that the influence of oxygenates on soot formation could be adverse depending on the nature of the precursor used and that general conclusions about oxygenates are quite difficult to draw.…”