Shock‐tube and modeling study of acetaldehyde pyrolysis and oxidation

Abstract

Pyrolysis and oxidation of acetaldehyde were studied behind reflected shock waves in the temperature range 1000-1700 K at total pressures between 1.2 and 2.8 atm. The study was carried out using the following methods, (1) time-resolved IR-laser absorption at 3.39 µm for acetaldehyde decay and CH-compound formation rates, (2) time-resolved UV absorption at 200 nm for CH 2 CO and C 2 H 4 product formation rates, (3) time-resolved UV absorption at 216 nm for CH 3 formation rates, (4) time-resolved UV absorption at 306.7 nm for OH radical formation rate, (5) time-resolved IR emission at 4.24 µm for the CO 2 formation rate, (6) time-resolved IR emission at 4.68 µm for the CO and CH 2 CO formation rate, and (7) a single-pulse technique for product yields. From a computer-simulation study, a 178-reaction mechanism that could satisfactorily model all of our data was constructed using new reactions, CH 3 CHO (+M) → CH 4 + CO (+M), CH 3 CHO (+M) → CH 2 CO + H 2 (+M),

An experimental and kinetic modeling study of the pyrolysis and oxidation of n-C3C5 aldehydes in shock tubes

“…Figure 1a shows the oxidation of formaldehyde in an atmospheric pressure flow reactor at 1095 K and φ = 1.08 [31], while figure 1b shows the high-temperature pyrolysis of acetaldehyde in a shock tube [43]. Figure 2 compares the ignition delay times of formaldehyde [34] and acetaldehyde [43] (1% fuel in oxygenargon) at lean conditions (φ = 0.5). The higher reactivity of formaldehyde is evident in this figure, mainly at lower temperatures.…”

“…Kaiser proposed a model to describe the negative temperature coefficient (NTC) behavior of acetaldehyde [40]. The high-temperature oxidation of acetaldehyde was investigated by Dagaut [41] in a jet-stirred reactor and in a shock tube, while Hidaka and co-workers studied its pyrolysis in a single-pulse shock tube [42], and Yasunaga suggested a mechanism describing the oxidation and pyrolysis for the hightemperature regime [43].…”

“…Figure 1: a) Oxidation of formaldehyde at 1 atm and 1095 K [31]. b) Pyrolysis of acetaldehyde at 2 atm and 2 ms residence time [43]. Comparison of experimental data (symbols) and predictions of NUIG (dashed lines) and POLIMI (solid lines) kinetic schemes.…”

Investigation of the chemical structures of laminar premixed flames fueled by acetaldehyde

“…Also, using a shock tube, Won et al [5] measured the ignition delay of acetaldehyde and proposed a mechanism consisting of 34 species and 110 reactions. Both pyrolysis and oxidation were investigated by Yasunaga et al [6] in three different shock tubes connected to laser/UV absorption or IR-emission equipment, which provided the concentration variations of hydrocarbon compounds and ketene during the reaction. In addition to the shock tube experiments, the unstretched laminar burning velocities of acetaldehyde/air flame at different equivalence ratios and initial temperatures were reported by Christensen et al [7] .…”

Formation of carbonyl compounds in lean premixed atmospheric-pressure Ethylene/O₂/N₂ flames

“…Their emissions are harmful to the environment as well as to human health and they should be reduced. In the last decade, formaldehyde and acetaldehyde have been studied in several experimental setups for various temperature and pressure conditions: for CH 2 O, in static reactors (Hay and Hessam, 1971), flow reactors (Vardanyan et al, 1971 and1974;Hochgreb et al, 1990;Glarborg et al, 2003), shock tubes (Drummond, 1971;Dean et al, 1979Dean et al, , 1980Hidaka et al, 1993aHidaka et al, , 1993bEitener et al, 1998;Friedrichs et al, 2004) and flames (Oldenhove et al, 1986;Kaiser et al, 1991;Corr et al, 1992;Dagaud et al, 1994;Curran et al, 1998;Zervas et al, 1999Zervas et al, , 2001Zervas et al, , 2002Zervas et al, , 2005Dias et al, 2012); and for CH 3 CHO, in static reactors (Kaiser et al, 1986), flow reactors (Colket et al, 1975(Colket et al, , 1977, shock tubes (Dagaut et al, 1995;Won et al, 2000;Yasunaga et al, 2007) and flames (Leplat and Vandooren, 2010). All these past studies have allowed the determination of the consumption pathways of such carbonyl compounds.…”