Effects of oxygenate additives on polycyclic aromatic hydrocarbons(pahs) and soot formation

Abstract

Effects of three oxygenate additives (methanol, ethanol, and MTBE) on the formation of polycyclic aromatic hydrocarbons (PAHs) and soot in laminar, premixed, atmospheric pressure, fuel-rich flames of n-heptane were studied at an equivalence ratio of 2.10. A heated quartz microprobe coupled to online gas chromatography=mass spectrometry was used to establish the identities and absolute concentrations of major, minor, and trace species by the direct analysis of samples withdrawn from the flames. Benzene was the most abundant aromatic compound identified. The largest PAH detected was the family of C 18 H 10 (molecular weight of 226) that includes cyclopenta[cd]pyrene and benzo[ghi]fluoranthene. Soot particle diameters, number densities, and volume fractions were determined using classical light scattering and extinction measurements. All the oxygenate additives studied reduced the mole fractions of aromatic and PAH species, as well as soot formation. However, the reduction in soot formation was comparable for different oxygenates under the experimental conditions investigated.

Identification of combustion intermediates in isomeric fuel-rich premixed butanol–oxygen flames at low pressure

“…All of these compounds have very low sooting tendencies as pure fuels [13]. Also, the role of oxygen-containing compounds as fuel additives was investigated by different research groups [3,7,[14][15][16][17]. Wu et al [18] studied the effect of ethanol addition to premixed ethylene-air flames.…”

Artificial neural network predictions of polycyclic aromatic hydrocarbon formation in premixed n-heptane flames

“…The output parameter was the total PAH mole fraction, which includes the sum of the mole fractions of seven PAH compounds: naphthalene, acenaphthylene, phenanthrene, 4H-cyclopenta[def]-phenanthrene, fluoranthene, pyrene, and cyclopenta[cd]pyrene. Benzene was the most abundant aromatic compound and acenaphthylene and naphthalene were the most abundant PAH compounds in all the flames studied [18]. Fifty-four data sets obtained from six flames were divided into three groups: training, cross-validation, and testing, each containing 30 (∼ 56%), 6 (∼ 11%), and 18 (∼ 33%) sets, respectively.…”

“…The details of the experimental setup used for data acquisition have been given elsewhere [17,18]. Therefore, only a brief description will be presented here.…”

“…In addition, ethanol is the only renewable fuel oxygenate. The effects of fuel oxygenate on PAH formation in n-heptane flames have been investigated by Inal and Senkan [18,19].…”

Influences of Waste Cooking Oil-Based Biodiesel Blends on PAH and PCDD/F Emissions from Diesel Engines in Durability Testing Cycle

“…They suggested several factors causing this phenomenon including the enhanced combustion efficiency, improved PAH oxidization of forming precursors due to increased oxygenation, dilution effect which reduces fuel PAH content, and absence of aromatic content in the biodiesel (Chang et al, 2014a). Furthermore, studies have reported that fuel at optimum conditions enhances chemical reactions of unsaturated hydrocarbons, which are precursors responsible for PAH emissions that may reduce total PAH emissions (Inal and Senkan, 2002;Cheruiyot et al, 2015). For EURO II, the total BaP eq were 2.17, 0.463, 0.337, and 0.353 µg BaP eq Nm -3 for 0, 20,000, 40,000, and 60,000 km, respectively, as shown in Table 5.…”