Fuel Additive Effects on Soot across a Suite of Laboratory Devices, Part 1: Ethanol

Litzinger, T A; Colket, Meredith B.; Kahandawala, M.; Katta, Viswanath R.; Lee, Seong-Young; Liscinsky, D. S.; McNesby, Kevin L.; Pawlik, R.; Roquemore, M.; Santoro, Robert J.; Sidhu, Sukh; Stouffer, Scott D.; Wu, Juntao

doi:10.1080/00102200802437445

Cited by 24 publications

(6 citation statements)

References 14 publications

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“…For example, the ratios of maximum measured mole fractions in F4 and F1 are 0.46 and 0.31 for naphthalene and biphenyl, respectively, which are much lower than those of toluene and benzyl. This indicates that the formation of these PAHs is suppressed with the n-butanol addition under the investigated conditions, which is consistent with the results of Litzinger et al 81 that the addition of oxygenated fuels can reduce the formation of PAHs in premixed flames. The main reason for the suppressed PAH formation with the n-butanol addition is the reduced concentrations of PAH precursors.…”

Section: Influence Of N-butanol Addition On Aromatic Growthsupporting

confidence: 92%

Experimental and kinetic modeling investigation of rich premixed toluene flames doped with n-butanol

Yuan

et al. 2018

Phys. Chem. Chem. Phys.

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n-Butanol is a promising renewable biofuel and has a lot of advantages as a gasoline additive compared with ethanol. Though the combustion of pure n-butanol has been extensively investigated, the chemical structures of large hydrocarbons doped with n-butanol, especially for aromatic fuels, are still insufficiently understood. In this work, rich premixed toluene/n-butanol/oxygen/argon flames were investigated at 30 Torr with synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). The blending ratio of n-butanol was varied from 0 to 50%, while the equivalence ratio was maintained at a quite rich value (1.75) for the purpose of studying the influence of n-butanol on the aromatic growth process. Flame species including radicals, reactive molecules, isomers and polycyclic aromatic hydrocarbons (PAHs) were identified and their mole fraction profiles were measured. A kinetic model of toluene/n-butanol combustion was developed from our recently reported toluene and n-butanol models. It is observed that the production of most toluene decomposition products and larger aromatics was suppressed as the blending ratio of n-butanol increases. Meanwhile, the addition of n-butanol generally enhanced the formation of most observed C2-C4 hydrocarbons and C1-C4 oxygenated species. The rate of production (ROP) analysis and experimental observations both indicate that the interaction between toluene and n-butanol in their decomposition processes mainly occurs at the formation of small intermediates, e.g. acetylene and methyl. In particular, the interaction between toluene and n-butanol in methyl formation influences the formation of large monocyclic aromatics such as ethylbenzene, styrene and phenylacetylene, making their maximum mole fractions decay slowly upon increasing the blending ratio of n-butanol compared with toluene and benzyl. The increase of the blending ratio of n-butanol reduces the formation of key PAH precursors such as benzyl, fulvenallenyl, benzene, phenyl and propargyl, which leads to a remarkable reduction in the formation of PAHs.

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Section: Influence Of N-butanol Addition On Aromatic Growthsupporting

confidence: 92%

Experimental and kinetic modeling investigation of rich premixed toluene flames doped with n-butanol

Yuan

et al. 2018

Phys. Chem. Chem. Phys.

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“…Besides C3H8, many other fuels, including CH4, C2H6, n-butane, iso-butane, dimethyl ether (CH3-O-CH3, DME), ethanol (C2H5-OH) and npropanol are known to meet these criteria. And indeed, the synergistic effects on PAH/soot formation have been observed for C2H4/C2H6 [586], C2H4/n-C4H10 [86], C2H4/i-C4H10 [86], C2H4/DME [90,100,476], C2H4/C2H5OH [41,101,607,667], C2H4/C3H7OH [666] mixtures, as summarized in Figure 25.…”

Section: B) Synergistic Effects Of Ethylene-based Binary Fuel Mixturesmentioning

confidence: 98%

“…In addition to the above technical constraints, the fact that physicochemical formation pathways of soot are still not fully understood-even in zero-dimensional systems-may provide enough rationale for the wide interests in soot studies with simple flow configurations. In this regard, various laboratory-scale setups have been employed, including constant volume combustion chambers [23][24][25][26][27][28][29][30], shock tubes [31][32][33][34][35][36][37][38][39][40], well-stirred reactors [41][42][43][44][45], burner-stabilized flat premixed flames [46][47][48][49][50][51][52][53][54][55], coflow diffusion flames [56][57][58][59][60][61][62][63][64][65][66][67][68]…”

Section: Laboratory-scale Experimental Configurationsmentioning

confidence: 99%

Soot formation in laminar counterflow flames

Wang

Chung

2019

Progress in Energy and Combustion Science

360

116

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Many practical soot-emitting combustion systems such as diesel and jet engines rely on diffusion flames for efficient and reliable operation. Efforts to mitigate soot emissions from these systems are dependent on fundamental understanding of the physicochemical pathways leading from fuel to soot in laminar diffusion flames. Existing diffusion flame−based soot studies focused primarily on overventilated coflow flame where the fuel gas (or vapor) issues from a cylindrical tube into a co-flowing oxidizer, and counterflow flame, where a reacting zone is established between two opposing streams of fuel and oxidizer. As a canonical diffusion flame configuration, laminar counterflow diffusion flames have been widely used as a highly controllable environment for soot research, enabling significant progress in the understanding of soot formation for several decades. In view of the possibility of fuel/oxidizer premixing in practical systems, counterflow partially premixed flames have also been studied. In the present work we intend to provide a comprehensive review of the researches on various aspects of soot formation utilizing counterflow flames. Major processes of soot formation (formation of gas phase soot precursors, soot inception and surface reactions, as well as particle-particle interactions) are examined first, with focus on the most recent (post-2010) research progress. Experimental techniques and associated challenges for the measurement of soot-related properties (some knowledge of which is helpful for full appreciation of the experimental data to be reviewed) are then introduced. This is followed by a detailed description of soot evolution in counterflow flames, which is complemented by a discussion on the similarity and differences of the sooting structures between counterflow and coflow diffusion flames. Parametric studies of the effects of fuel molecular structure, fuel additive, partial-premixing, pressure, temperature, stoichiometric mixture fraction, and residence time on soot formation in counterflow flames will then be addressed in detail. This review concludes with a summary of the knowledge and challenges gathered and demonstrated through decades of research, and an outlook on opportunities for future counterflow flame−based soot research towards a more complete understanding of soot formation and the development of novel techniques for soot mitigation in practical combustion devices.

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“…With the rapid depletion of fossil fuels, biofuels have been recognized as one of the most potential alternative energy sources. − As a typical class of biofuels, alcohols have aroused increasing interest in recent years. Alcohols have been widely used as alternative fuels or fuel additives, because they can effectively inhibit the formation of polyaromatic hydrocarbons (PAHs) and soot in combustion processes. − As we know, bioethanol has already been blended with gasoline for use in combustion internal engines and biobutanol has even been directly used without blending. , Although large amounts of investigations have been carried out on monohydric alcohols (such as methanol, ethanol, propanol and butanol), − polyols gained less attention. Yet polyols are one of the principal components of plant matter, from which biofuels are derived.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Studies on the Unimolecular Decomposition of Ethylene Glycol

Zhao

Zhang

et al. 2011

J. Phys. Chem. A

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The unimolecular decomposition processes of ethylene glycol have been investigated with the QCISD(T) method with geometries optimized at the B3LYP/6-311++G(d,p) level. Among the decomposition channels identified, the H(2)O-elimination channels have the lowest barriers, and the C-C bond dissociation is the lowest-energy dissociation channel among the barrierless reactions (the direct bond cleavage reactions). The temperature and pressure dependent rate constant calculations show that the H(2)O-elimination reactions are predominant at low temperature, whereas at high temperature, the direct C-C bond dissociation reaction is dominant. At 1 atm, in the temperature range 500-2000 K, the calculated rate constant is expressed to be 7.63 × 10(47)T(-10.38) exp(-42262/T) for the channel CH(2)OHCH(2)OH → CH(2)CHOH + H(2)O, and 2.48 × 10(51)T(-11.58) exp(-43593/T) for the channel CH(2)OHCH(2)OH → CH(3)CHO + H(2)O, whereas for the direct bond dissociation reaction CH(2)OHCH(2)OH → CH(2)OH + CH(2)OH the rate constant expression is 1.04 × 10(71)T(-16.16) exp(-52414/T).

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Fuel Additive Effects on Soot across a Suite of Laboratory Devices, Part 1: Ethanol

Cited by 24 publications

References 14 publications

Experimental and kinetic modeling investigation of rich premixed toluene flames doped with n-butanol

Experimental and kinetic modeling investigation of rich premixed toluene flames doped with n-butanol

Soot formation in laminar counterflow flames

Theoretical Studies on the Unimolecular Decomposition of Ethylene Glycol

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