Kinetic Mechanism Development for Hydrocarbons and Oxygenated Fuels

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1 Kinetic Mechanism Development for ydrocarbons and Oxygenated Fuels Dr. enry Curran and Dr. Philippe Dagaut Combustion Chemistry Centre, NUI Galway, Ireland CNRS Orleans, France Lecture 1 st Workshop on Flame Chemistry July 28 th,

Biodiesel from vegetable and animal oils Chemical kinetics to understand and simulate complex

2 Future C fuels - many sources Some petroleum will still be available Oil sands, oil shale Coal-to-liquids Fischer Tropsch Natural gas ydrogen Bio-derived fuels Ethanol, butanol, algae Biodiesel from vegetable and animal oils Chemical kinetics to understand and simulate complex behaviour (ignition, NTC, cool flames ) reactivity (extent of conversion, heat release) product / pollutant formation 2

3 Percentage of fuel carbon converted to soot precursors ow well an oxygenated fuel works depends on its molecular structure Reference fuel mixed with: MB DMM TPGME Ethanol Methanol DME Dibuthylmaleate Fraction of oxygen in fuel by mass Miyamoto et al. Paper No. SAE (1998). Westbrook et al. J. Phys. Chem. A (2006) 110:

4 Oxygenated fuels Alcohols (methanol, ethanol, propanol, butanol) Ethers (DME, DEE, EME, MTBE, ETBE) Esters (methyl and ethyl esters) Ketones (acetone, EMK, DEK) Furans (methyl furan, di-methyl furan) 4

5 General reaction scheme igh temperature Fuel smaller molecules β-scission + O 2 Ṙ RO 2 + O 2 olefins, cyclic ethers, β-scission Intermediate temperature QOO Low temperature + O 2 chain branching 5

6 Fuel decomposition reactions 6

7 Ignition delay time ( s) Propanol isomers: Comparison of reactivity 0.5% fuel, 2.25% O 2, f = 1.0, P = 1 atm 1000 iso -propanol n -propanol K / T Johnson et al. Energy & Fuels (2009)

8 Alcohol molecular elimination 3 C C C O n-propanol 3 C C C iso-propanol propene + water k = 3.52 x s -1 O k = 2.11 x s -1 + O + O propene + water Tsang, W. Int. J. Chem. Kinet. (1976) 8:

9 Water elimination is much more important for isopropanol C C C 2 O 3 C C C 2 O (2C36O) (5%) 3 C C 2 C 2 O (nc37o) O (10%) 3 C C 2 C 2 O (3%) (nc37o) (7.8%) O (4.7%) - (1.5%) (10.9%) O (7.6%) 3 C C C O (1C36O) (14%) 2 C C O + C 3 2 C C 2 C 2 (3C36O) O 0.5% n-propanol f = 1.0, T = 1600 K 30% fuel consumed (13%) (29%) (18.5%) 3 C C C 2 + O 3 C C C O 2 C C C O C C C O (C23O) C C C O (sc24o) C 3 2 C C O + (ic35o) 0.5% iso-propanol (5.5%) (5.6%) (5.6%) f = 1.0, T = 1600 K 30% fuel consumed C 2 (10%) 3 C C O O (5.2%) (ic36o) O (1.6%) (11.5%) C 3 3 C C O (ic37o) (63%) (7.7%) O (5.8%) C 3 3 C C O (tc36o) (7.2%) O 3 C C C 2 + O 3 C C C O 3 C C C 3 + (C36) (C36) (C3COC3) Johnson et al. Energy & Fuels (2009) 23:

10 General reaction scheme igh temperature Fuel smaller molecules β-scission + O 2 Ṙ RO 2 + O 2 olefins, cyclic ethers, β-scission Intermediate temperature QOO Low temperature + O 2 chain branching 10

11 Sub-mechanism 11

12 Reactivity of ethers 1% 2, 1% O 2 in Ar, p 5 = atm 0.1% iso-c % MTBE 0.1% ETBE 0.1% DEE 0.1% EME Yasunaga et al. Comb. Flame (2011) 158:

13 Ether molecular elimination C 3 C C O 3 C MTBE C C O isobutene + methanol k = 1.70 x s -1 C C 3 C 3 C O C 2 C 3 ETBE + 3 C C 2 O isobutene + ethanol k = 1.70 x s -1 Yasunaga et al. Comb. Flame (2011) 158: MP4/cc-pVTZ//MP2/cc-pVTZ level of theory with zero point corrections 13

14 3 C 3 C C 2 C Ether molecular elimination 3 C C C O C 2 ETBE C 2 C O C 2 O C 3 EME C 3 C 3 C O + 2 C C 2 tert-butanol + ethylene C 3 2 C C C C 2 O DEE ethylene + ethanol 3 MP4/cc-pVTZ//MP2/cc-pVTZ level of theory with zero point corrections C 2 C C 2 + C O ethylene + methanol Yasunaga et al. Comb. Flame (2011) 158: k = 5.0 x s -1 k = 5.0 x s -1

15 Ethylene is very fast to ignite C 2 4 C 3 6 i-c 4 8 C 2 6 C % fuel, f = 1.0 / s 10 3 i-c K / T 15

16 General reaction scheme igh temperature smaller molecules β-scission + O 2 olefins, cyclic ethers, β-scission Fuel -atom abstraction + O 2 Ṙ RO 2 QOO Low temperature + O 2 chain branching Intermediate temperature 16

17 -atom abstraction reactions 17

18 Acetone: Low p, igh T 1.25% fuel, 22% fuel conversion, T = 1400 K, p = 1 atm CO + C 3 C 2 6 C 3 CO + C 3 53% (f = 0.5) 64% (f = 1.0) 70% (f = 2.0) C 3 COC 2 + C 4 + C 3 4% (f = 0.5) 5% (f = 1.0) 5% (f = 2.0) O 3 C C C % (f = 0.5) 17% (f = 1.0) 17% (f = 2.0) 26% (f = 0.5) 14% (f = 1.0) 8% (f = 2.0) + O C 3 COC O C 3 COC C 3 + C 2 CO C

19 k (cm 3 mol -1 s -1 ) C 3 COC 3 + O = C 3 COC O 1E12 This study Gierczak et al. 03 (PLIF) Wollenhaupt et al. 00 (PLIF) Yamada et al. 03 (PLIF) Vasudevan et al. 05 1E K / T 19

k (cm 3 mol -1 s -1 ) C 3 OC 3 + O = C 3 OC 2 + 2 O 1E13 Curran et al. 00 Ogura et al. 07 Bonard et al. 02 Tranter/Walker 01 Atkinson 97 Arif et al.

20 k (cm 3 mol -1 s -1 ) C 3 OC 3 + O = C 3 OC O 1E13 Curran et al. 00 Ogura et al. 07 Bonard et al. 02 Tranter/Walker 01 Atkinson 97 Arif et al. 97 Mellouki et al. 95 Nelson et al. 90 Wallington et al. 88 Tully/Droege 87 Perry et al. 77 1E K / T 20

21 k (cm 3 mol -1 s -1 ) C 3 OC 3 + O = C 3 OC O 1E13 Cook et al. 09 Curran et al. 00 Ogura et al. 07 Bonard et al. 02 Tranter/Walker 01 Atkinson 97 Arif et al. 97 Mellouki et al. 95 Nelson et al. 90 Wallington et al. 88 Tully/Droege 87 Perry et al. 77 1E K / T 21

-atom Abstraction n-butanol + O/O 2 Ethers + O C-W. Zhou, J. M.

Zhou, J. M. Simmie,. J. Curran. Int. J. Chem. Kinet.

n-butanol + Ċ 3 (Imperial College London: Prof. Alex Taylor ) D.

ardalupas, A.M.K.P. Taylor. Proc. Comb. Inst., 2012.

22 -atom Abstraction n-butanol + O/O 2 Ethers + O C-W. Zhou, J. M. Simmie,. J. Curran. Combust. & Flame, C-W. Zhou, J. M. Simmie,. J. Curran. Int. J. Chem. Kinet., n-butanol + Ċ 3 (Imperial College London: Prof. Alex Taylor ) D. Katsikadakos, C-W. Zhou, J. M. Simmie,. J. Curran, P.A. unt, Y. ardalupas, A.M.K.P. Taylor. Proc. Comb. Inst., Paper 4D03 Thursday 2 nd August. ' ' ' ' DME EME ipme C-W. Zhou, J.M. Simmie,.J. Curran Phys. Chem. Chem. Phys

23 Ketones + O -atom Abstraction ' ' ' ' DMK EMK ipmk C-W. Zhou, J. M. Simmie,. J. Curran. Phys. Chem. Chem. Phys iso-butanol decomposition and related (C 3 ) 2 Ċ + Ċ 2 O reaction (Argonne National Laboratory: Dr. Stephen Klippenstein) ' + C-W. Zhou, S. J. Klippenstein, J. M. Simmie,. J. Curran Proc. Comb. Inst., 2012 in press Paper : 4D05 Thursday 2 nd August 23

24 log (k / cm 3 mol -1 s -1 ) C 3 O + O 2 C 2 O + 2 O 2 T / K A n E 10 8 Zhou Klippenstein Curran Li Zhou Klippenstein Curran Li 6.24E E E E E E E E+04 6 k AT n exp( E /RT) --- in cm 3, mol, s, cal units K / T Klippenstein, S J.; arding, L B.; Davis, M J. et al. Proc. Comb. Inst Li, J.; Zhao, Z.; Kazakov, A.; Chaos, M.; Dryer, F L. et al. Int. J. Chem. Kinet

25 Acetone: α' hydrogen reactivity TS2a 2.3 TS1a DMK + O RC1a -4.5 in kcal/mol C 3 COC O TS1a PC1a RC1a TS2a 25

26 Acetone: α' hydrogen reactivity T / K k / cm 3 mol -1 s -1 Branching Ratio 1.0 1E12 Outofplane Inplane Outofplane Inplane 0.4 1E K / T T / K C O C E CT = 2.0 kcal/mol E CT = 0.0 kcal/mol Electron delocalization from π(co) to σ*(c in ) and σ*(c out ) is different 26

27 k / cm 3 mol -1 s -1 Branching Ratio α' hydrogen reactivity in DME T / K E13 Outofplane Inplane 0.8 Outofplane Inplane 0.6 1E E K / T T / K O C C E CT = 4.9 kcal/mol E CT = 1.7 kcal/mol Electron delocalization from oxygen lone pairs to σ*(c out ) weaken the BDE of out-of-plane C bond by 5.0 kcal/mol. 27

28 k / cm 3 mol -1 s -1 α' Reactivity Compared to Alkanes T / K E13 Ethers 1E12 Michael et al. 1E11 Ketones Ethers Oxygen lone pairs accelerate reactivity of hydrogen compared to alkane Growing size of the -side has no influence on reactivity of hydrogen atoms Ketones K / T -atom is less reactive than primary -atom in alkanes Growing size of the -side will accelerate reactivity of -atoms 28

29 k / cm 3 mol -1 s -1 k (cm 3 mol -1 s -1 ) Comparative Reactivity T / K E13 Ethers 1E13 Acetone DME 1E12 Michael et al. 1E12 1E11 Ketones 1E K / T 1E K / T 29

30 igh temperature General reaction scheme Fuel Smaller molecules β-scission -atom abstraction + O 2 Ṙ RO 2 + O 2 olefins, cyclic ethers, β-scission Intermediate temperature QOO Low temperature + O 2 30

31 Low-temperature chemistry 31

32 Alcohol Oxidation Aldehyde formation from -radical + O 2 O + O O + 2O O O O 2 O O O O O + O2 32

33 Alcohol Oxidation Waddington mechanism ( -radical + O 2 ) O + O O + 2O O 2 O O O O O O O + C2O + O 33

t ign [ms] Comparison: Alcohol/Alkane Oxidation 1000 100 n-butanol 15

34 t ign [ms] Comparison: Alcohol/Alkane Oxidation n-butanol 15 bar n-butane 18 bar /T [1/K] 34

35 Effect of chain length 35

36 t ign [ms] t ign [ms] Alcohol Oxidation Effect of chain length on influence of functional group n-butanol vs n-butane n-pentanol vs n-pentane n-pentanol 9 bar 100 n-butanol 15 bar n-butane 18 bar 100 n-pentane 8-11 bar /T [1/K] /T [1/K] eufer et al. Proc. Comb. Inst. (2012) in press. Paper 4D06, Thursday 2 nd August 36

37 % Soybean and rapeseed derived biodiesels have only 5 principal components R O triglyceride R O O O O O + 3 C 3O methanol Fatty acid methyl esters (FAMEs): O 3 C 3 + R O Methyl Palmitate (C16:0) O O methyl ester glycerol O 3 C 3 O methanol R O 3 C 3 + R O methyl ester O O O glycerol Methyl Stearate (C18:0) Methyl Oleate (C18:1) Soybean Rapeseed Methyl Linoleate (C18:2) Methyl Linolenate (C18:3) C16:0 C18:0 C18:1 C18:2 C18:3 Westbrook et al. Proc. Comb. Inst. (2012) in press. Paper 3D03 Wednesday 1 st August 37

38 Biodiesel components ignite in order of number of double bonds Ignition delay - ms stearate linoleate palmitate oleate Engine-like conditions: 13.5 bar Stoichiometric fuel/air mixtures linolenate /T - K Westbrook et al. Proc. Comb. Inst. (2012) in press. Paper 3D03 Wednesday 1 st August 38

39 C = C double bonds reduce low T reactivity s s a v v a s s - C C C C = C C C C - s s a a s s Inserting one C=C double bonds changes the reactivity of 4 carbons atoms in the C chain Allylic C bond sites are weaker than most others Therefore they are preferentially abstracted by radicals O 2 is also very weakly bound at allylic sites and falls off rapidly, inhibiting low T reactivity Westbrook et al. Proc. Comb. Inst. (2012) in press. Paper 3D03 Wednesday 1 st August 39

Ignition delay time [ms] Observed same effect in hydrocarbon fuels: hexenes C = C - C - C - C - C C - C = C - C - C - C C - C - C = C - C - C 1-hexene 2-hexene 3-hexene Ignition delay times in a

40 Ignition delay time [ms] Observed same effect in hydrocarbon fuels: hexenes C = C - C - C - C - C C - C = C - C - C - C C - C - C = C - C - C 1-hexene 2-hexene 3-hexene Ignition delay times in a rapid compression machine of hexene isomers ( MPa, Φ=1): exene 3-exene RO 2 isomerization initiates low temperature reactivity Moving the double bond towards the center 20 1-exene T [K] of the molecule inhibits RO 2 kinetics Experimental data: Vanhove et al. PCI 2005 Simulations: Mehl, Vanhove, Pitz, Ranzi Combustion and Flame 155 (2008)

41 Novel fuels 41

Furans vs bio-ethanol Promising Next Generation Biofuels Roman-Leshkov et al., Nature (2007) 447: 982-985.

42 Furans vs bio-ethanol Promising Next Generation Biofuels Roman-Leshkov et al., Nature (2007) 447: (2 nd generation) Novel renewable production process Biomass (lignocellulosic) feedstock not destined for human/animal consumption ighly efficient Large scale and low cost Desirable physicochemical properties igher energy density (40%) Direct combustion in unmodified engine RON = 119 Lower aqueous solubility and less volatile Laminar Flame Speed Measurements of DMF, Ethanol and Gasoline, Tian et al., Energy Fuels, 2010 Energy Densities: Gasoline: 2,5-DMF: 35 MJ/L 31 MJ/L Bio-Ethanol: 23 MJ/L Session 1: Monday morning: Kinetics of Cyclic Ethers 42

43 2MF: Unimolecular Decomposition Energies (0 K, kj / mol) CBS-QB3, CBS-APNO, G3 Somers et al. Comb. Inst. (2012) in press. Paper1D01 Monday 30 th July 43

44 Conclusions General chemical reaction schemes of Cs can be applied to oxygenated fuels Details of oxygenated fuel combustion are quite different! 44

Oxidation of C 3 and n-c 4 aldehydes at low temperatures

Oxidation of C 3 and n-c 4 aldehydes at low temperatures M. Pelucchi*, A. Frassoldati*, E. Ranzi*, T. Faravelli* matteo.pelucchi@polimi.it * CRECK-Department of Chemistry, Materials and Chemical Engineering