ARTICLE pubs.acs.org/EF
Experimental and Detailed Kinetic Modeling Study of Isoamyl Alcohol (Isopentanol) Oxidation in a Jet-Stirred Reactor at Elevated Pressure Guillaume Dayma,*,† Casimir Togbe,‡ and Philippe Dagaut‡ † ‡
Faculte des Sciences 1 rue de Chartres, Universite d’Orleans, BP 6759, 45067 Orleans cedex 2, France Institut des Sciences de l’Ingenierie et des Systemes (INSIS), Centre National de la Recherche Scientifique (CNRS), 1C, Avenue de la Recherche Scientifique, 45071 Orleans cedex 2, France
bS Supporting Information ABSTRACT: Isoamyl alcohol (isopentanol or 3-methylbutan-1-ol) that can be biologically produced is among the possible alcohols usable as an alternative fuel in internal combustion engines. It has a higher energy density than smaller alcohols (ca. 28.5 MJ/L, as compared to ca. 21 MJ/L for ethanol and 27 MJ/L for 1-butanol). It is less hydroscopic than ethanol and mixes better with hydrocarbons. To better understand the combustion characteristics of that alcohol, new experimental data were obtained for its kinetics of oxidation in a jet-stirred reactor (JSR). Concentration profiles of stable species were measured in a JSR at 10 atm over a range of equivalence ratios (0.354) and temperatures (5301220 K). The oxidation of isopentanol was modeled using an extended detailed chemical kinetic reaction mechanism (2170 reactions involving 419 species) derived from a previously proposed scheme for the oxidation of a variety of fuels. The proposed mechanism shows good agreement with the present experimental data. Reaction path and sensitivity analyses were conducted for interpreting the results.
1. INTRODUCTION Because of their sustainable character, biofuels are attracting great interest as transportation fuels. Potentially, they can be locally produced, may be less polluting, sometimes more biodegradable than fossil fuels, and could reduce net greenhouse gas emissions.13 Today, ethanol accounts for over 90% of worldwide biofuel production. However, mixing stability issues may appear with blends containing simple alcohols, whereas larger alcohols mix better with fossil fuels thanks to their longer alkyl chain. Because 1-butanol was announced to be sold in the near future as a gasoline-blending constituent,4 several studies have been performed on its kinetics of oxidation. For example, Dagaut and Togbe studied the oxidation of butanolgasoline surrogate mixtures (8515 vol %) in a jet-stirred reactor (JSR) at 10 atm, and a kinetic reaction mechanism was derived for modeling the oxidation of that fuel.5 Later, longer carbon-chain alcohols, which could be blended with conventional fuels, i.e., 1-pentanol and 1-hexanol, were considered in chemical kinetic studies.6,7 More recently, the interest for using isopentanol in engines was demonstrated.8 In fact, isopentanol has several advantages over smaller alcohols, such as ethanol; it has a high energy density (ca. 28.5 MJ/L, as compared to ca. 21 MJ/L for ethanol and 27 MJ/L for 1-butanol), close to that of gasoline (ca. 32 MJ/L). It is also less hydroscopic than ethanol and mixes better with hydrocarbons. Moreover, isopentanol has a much lower vapor pressure at 293 K (0.27 kPa) than ethanol (5.95 kPa). However, whereas isopentanol could also be produced biologically,911 only engine experiments were reported in the literature,8 which is not enough to assess the kinetics of isopentanol oxidation. Therefore, kinetic studies of the oxidation of that fuel were needed. The aim of this work is to provide new experimental data and a model for the kinetics of isopentanol oxidation under well-defined conditions. New results consisting of stable species concentration r 2011 American Chemical Society
Table 1. Structure, Nomenclature, and Heat of Formation (in kcal mol1) at 298 K of Selected Species
profiles obtained for isopentanol oxidation in a JSR at 10 atm (10.13 105 Pa) over a range of equivalence ratios and temperatures are reported here. This new data set was used to validate a detailed chemical kinetic model for isopentanol oxidation needed for future engine combustion modeling.
2. EXPERIMENTAL SECTION The JSR experimental setup used here has been described earlier.7,12 The reactor consists of a 4 cm diameter fused silica sphere (42 cm3) equipped with four nozzles of 1 mm inner diameter. Prior to the Received: August 8, 2011 Revised: October 6, 2011 Published: October 06, 2011 4986
dx.doi.org/10.1021/ef2012112 | Energy Fuels 2011, 25, 4986–4998
Energy & Fuels
ARTICLE
Table 2. Isopentanol Submechanism (in cm3, mol, s1, and cal) number 1638
A
reaction
n
Ea
butoh3m (+M) = buto3m + H (+M)
6.04 1014
0.1
103800
low pressure limit
2.41 1039
7.03
96000
notea a
TROE centering: 3.87 101/5.65 102/4.44 109/6.71 109 1639
butoh3m = butoh3m-2 + H
5.00 1015
0
94990
b
1640
butoh3m = butoh3m-3 + H
5.00 1015
0
94990
b
1641
butoh3m = butoh3m-4 + H
1.58 1016
0
97970
b
1642
butoh3m = butoh-3 + CH3
2.00 1017
0
84650
b
1643 1644
butoh3m = pC2H4OH + iC3H7 butoh3m (+M) = iC4H9 + CH2OH (+M)
1.58 1017 3.02 1023
0 1.9
85280 85710
estd. a
1.42 1059
11.9
84000
low pressure limit 1
TROE centering: 7.65 10 /8.34 10 /7.25 10 /8.21 10 1645
9
2
9
butoh3m (+M) = but2m-4 + OH (+M)
6.33 1020
1.4
94930
low pressure limit
6.90 1051
10.2
89200
a
TROE centering: 7.03 101/9.88 109/6.35 102/1.79 109 1646
butoh3m + O2 = butoh3m-1 + HO2
1.50 1013
0
50150
c
1647
reverse Arrhenius coefficients butoh3m + O2 = butoh3m-2 + HO2
1.08 109 3.97 1013
0.6 0
504 47690
d
1648
butoh3m + O2 = butoh3m-3 + HO2
3.97 1013
0
43920
d
1649
butoh3m + O2 = butoh3m-4 + HO2
3.97 1013
0
50870
d
1650
butoh3m (+M) = H2O + but3m1d (+M)
3.52 1013
0
67230
a
low pressure limit
1.69 1075
17
64800
TROE centering: 8.00 102/1.00 100/9.92 109/9.92 109 1651
butoh3m + O = buto3m + OH
1.46 103
4.7
1727
e
1652 1653
butoh3m + O = butoh3m-1 + OH butoh3m + O = butoh3m-2 + OH
1.45 105 4.77 104
2.4 2.7
876 2106
e f
1654
butoh3m + O = butoh3m-3 + OH
1.00 1013
0
3280
f
1655
butoh3m + O = butoh3m-4 + OH
1.93 105
2.7
3716
f
1656
butoh3m + H = buto3m + H2
5.55 1023
10.6
4459
g
1657
butoh3m + H = butoh3m-1 + H2
1.79 105
2.5
3420
g
1658
butoh3m + H = butoh3m-2 + H2
1.30 106
2.4
4471
f
1659
butoh3m + H = butoh3m-3 + H2
4.20 106
2
2400
f
1660 1661
butoh3m + H = butoh3m-4 + H2 butoh3m + OH = buto3m + H2O
1.88 105 2.81 102
2.8 3
6280 580
f h
1662
butoh3m + OH = butoh3m-1 + H2O
1.31 105
2.4
1457
h
1663
butoh3m + OH = butoh3m-2 + H2O
4.68 107
1.6
35
f
1664
butoh3m + OH = butoh3m-3 + H2O
1.10 106
2
1870
f
1665
butoh3m + OH = butoh3m-4 + H2O
1.05 1010
1
1590
f
1666
butoh3m + HO2 = buto3m + H2O2
2.50 1012
0
24000
c
1667
butoh3m + HO2 = butoh3m-1 + H2O2
8.20 103
2.5
10750
c
1668 1669
butoh3m + HO2 = butoh3m-2 + H2O2 butoh3m + HO2 = butoh3m-3 + H2O2
5.60 1012 1.00 1012
0 0
17690 14000
f f
1670
butoh3m + HO2 = butoh3m-4 + H2O2
1.68 1013
0
20440
f
1671
butoh3m + CH3 = buto3m + CH4
2.04 100
3.6
7722
i
1672
butoh3m + CH3 = butoh3m-1 + CH4
1.99 101
3.4
7635
i
1673
butoh3m + CH3 = butoh3m-2 + CH4
2.70 104
2.3
7287
f
1674
butoh3m + CH3 = butoh3m-3 + CH4
1.00 1011
0
7900
f
1675
butoh3m + CH3 = butoh3m-4 + CH4
9.04 101
3.6
7154
f
1676 1677
butoh3m + CH3O = butoh3m-1 + CH3OH butoh3m + CH3O = butoh3m-2 + CH3OH
1.10 1011 1.10 1011
0 0
5000 5000
f f
1678
butoh3m + CH3O = butoh3m-3 + CH3OH
1.90 1010
0
2800
f
1679
butoh3m + CH3O = butoh3m-4 + CH3OH
2.16 1011
0
7000
f
1680
butoh3m + CH3O2 = butoh3m-1 + CH3O2H
5.60 1012
0
17690
f
1681
butoh3m + CH3O2 = butoh3m-2 + CH3O2H
5.60 1012
0
17690
f
1682
butoh3m + CH3O2 = butoh3m-3 + CH3O2H
1.50 1012
0
15000
f
4987
dx.doi.org/10.1021/ef2012112 |Energy Fuels 2011, 25, 4986–4998
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Table 2. Continued number
reaction
A
n
Ea
notea
1683 1684
butoh3m + CH3O2 = butoh3m-4 + CH3O2H butoh3m + C2H3 = butoh3m-1 + C2H4
1.68 1013 4.00 1011
0 0
20440 16800
f f
1685
butoh3m + C2H3 = butoh3m-2 + C2H4
4.00 1011
0
16800
f
1686
butoh3m + C2H3 = butoh3m-3 + C2H4
2.00 1011
0
16800
f
1687
butoh3m + C2H3 = butoh3m-4 + C2H4
1.02 1012
0
18000
f
1688
butoh3m + C2H5 = butoh3m-1 + C2H6
5.00 1010
0
10400
f
1689
butoh3m + C2H5 = butoh3m-2 + C2H6
5.00 1010
0
10400
f
1690
butoh3m + C2H5 = butoh3m-3 + C2H6
2.50 1010
0
10400
f
1691 1692
butoh3m + C2H5 = butoh3m-4 + C2H6 buto3m = CH2O + iC4H9
1.02 1011 1.00 1013
0 0
13400 13190
f j
1693
butoh3m-1 = CH3CHO + iC3H7
1.52 1012
0.6
31120
estd.
1694
butoh3m-2 = butoh2d + CH3
2.00 1013
0
31000
f
1695
butoh3m-3 = iC4H8 + CH2OH
2.00 1013
0
27700
estd.
1696
butoh3m-4 = C3H6 + pC2H4OH
2.37 1012
0.5
28890
a
1697
butoh3m-4 = CH3 + butoh3d
2.00 1013
0
31000
f
1698
butoh3m-2 = but3m1d + OH
6.67 1015
0.9
27660
a
1699
reverse Arrhenius coefficients buto3m = butal3m + H
9.93 1011 8.89 1010
0 0.5
960 2620
k
1700
butoh3m-1 = butal3m + H
3.07 1014
0.5
34700
a
1701
butoh3m-2 + M = butal3m + H + M
1.00 1014
0
25000
c
1702
butoh3m-2 = butoh3m2d + H
1.50 1013
0
37500
f
1703
butoh3m-3 = butoh3m2d + H
3.00 1013
0
38000
f
1704
butoh3m-3 = butoh3m3d + H
6.00 1013
0
39000
f
1705
butoh3m-4 = butoh3m3d + H
1.50 1013
0
37500
f
1706 1707
buto3m + O2 = butal3m + HO2 butoh3m-1 + O2 = butal3m + HO2
4.00 1010 1.00 1013
0 0
1100 5564
l m
1708
butoh3m-2 + O2 = butal3m + HO2
4.50 1011
0
2500
n
1709
butoh3m-2 + O2 = butoh3m2d + HO2
4.50 1011
0
5000
n
1710
butoh3m-3 + O2 = butoh3m2d + HO2
1.58 1012
0
5000
n
1711
butoh3m-3 + O2 = butoh3m3d + HO2
1.38 1012
0
5000
n
1712
butoh3m-4 + O2 = butoh3m3d + HO2
4.50 1011
0
5000
n
1713
butoh3m3d + OH = CH2O + butoh-3
1.37 1012
0
1040
o
1714 1715
butoh3m3d + OH = CH3COCH3 + pC2H4OH butoh3m2d + OH = CH3COCH3 + pC2H4OH
1.37 1012 1.37 1012
0 0
1040 1040
o o
1716
but3m1d + OH = CH2O + iC4H9
1.37 1012
0
1040
o
1717
but3m1d + OH = CH3CHO + iC3H7
1.37 1012
0
1040
o
1718
but3m1d + OH = CH3 + iC3H7CHO
1.37 1012
0
1040
o
1719
butoh2d + OH = CH3CHO + pC2H4OH
1.37 1012
0
1040
o
1720
butoh2d + OH = C2H5CHO + CH2OH
1.37 1012
0
1040
o
1721
butoh3d + OH = CH3CHO + pC2H4OH
1.37 1012
0
1040
o
1722 1723
but3m1d = C4H7-3 + CH3 but3m1d + H = iC4H8 + CH3
2.00 1016 7.23 1012
0 0
72930 1302
b p
1724
but3m1d + H = but2m-3
1.32 1013
0
1560
f
1725
but3m1d + H = but2m-4
1.32 1013
0
3260
f
1726
but3m1d + CH3 = pent2m-3
1.69 1011
0
7400
f
1727
but3m1d + CH3 = but2m3m-1
9.64 1010
0
8000
f
1728
but2m-3 = c2C4H8 + CH3
2.00 1013
0
31000
f
1729
but2m-3 = t2C4H8 + CH3
2.00 1013
0
31000
f
1730 1731
but2m-4 = C2H4 + iC3H7 pent2m-3 = c2C5H10 + CH3
2.00 1013 2.00 1013
0 0
27700 31000
f f
1732
pent2m-3 = t2C5H10 + CH3
2.00 1013
0
31000
f
1733
but2m3m-1 = C3H6 + iC3H7
2.00 1013
0
27700
f
1734
butoh2d + O = HOC4H6 + OH
1.74 1011
0.7
5900
f
1735
butoh2d + H = HOC4H6 + H2
1.74 105
2.5
2510
f
4988
dx.doi.org/10.1021/ef2012112 |Energy Fuels 2011, 25, 4986–4998
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Table 2. Continued number
A
reaction
n
notea
Ea
1736 1737
butoh2d + OH = HOC4H6 + H2O butoh2d + HO2 = HOC4H6 + H2O2
3.00 106 9.60 103
2 2.6
298 13900
f f
1738
butoh2d + CH3 = HOC4H6 + CH4
2.22 100
3.5
5670
f
1739
butoh2d + O = HOC4H6-2 + OH
8.80 1010
0.7
3250
f
1740
butoh2d + H = HOC4H6-2 + H2
5.40 104
2.5
1900
f
1741
butoh2d + OH = HOC4H6-2 + H2O
3.00 106
2
1520
f
1742
butoh2d + HO2 = HOC4H6-2 + H2O2
6.40 103
2.6
12400
f
1743
butoh2d + CH3 = HOC4H6-2 + CH4
1.00 1011
0
7300
f
1744 1745
HOC4H6-2 + O2 = sC3H5CHO + HO2 HOC4H6-2 = sC3H5CHO + H
7.90 1011 2.50 1013
0 0
5000 29000
n f
1746
butoh2d = C4H7-3 + OH
5.89 1019
1
95950
a
1747
butoh2d = C3H5-s + CH2OH
2.21 1022
1.6
97520
a
reverse Arrhenius coefficients
2.41 1013
0
butoh3d + O = HOC4H6 + OH
8.80 1010
0.7
reverse Arrhenius coefficients
2.00 1013
0
1749
butoh3d + H = HOC4H6 + H2
5.40 104
2.5
1900
f
1750 1751
butoh3d + OH = HOC4H6 + H2O butoh3d + HO2 = HOC4H6 + H2O2
3.00 106 6.40 103
2 2.6
1520 12400
f f
1752
butoh3d + CH3 = HOC4H6 + CH4
1.00 1011
0
7300
f
1753
HOC4H6 + H = butoh2d
1.00 1014
0
0
f
1754
HOC4H6 + H = butoh3d
1.00 1014
0
0
f
1755
but3m1d + H = but3m1dt + H2
2.50 104
2.5
2790
f
1756
but3m1d + OH = but3m1dt + H2O
1.30 106
2
2620
f
1757
but3m1d + HO2 = but3m1dt + H2O2
1.60 104
2.6
10900
f
1758 1759
but3m1d + CH3 = but3m1dt + CH4 but3m1dt + O2 = isope + HO2
5.00 1010 1.38 1012
0 0
5600 15200
f n
1760
isope + H = but3m1dt
1.00 1014
0
0
f
1761
but3m1dt + H = but3m1d
1.00 1014
0
0
f
1762
but3m1dt + H = but2m2d
1.00 1014
0
0
f
1763
but3m1dt + HO2 = CH3COCH3 + C2H3 + OH
4.50 1012
0
0
q
1764
but3m1dt + HO2 = iC4H7v + CH2O + OH
4.50 1012
0
0
q
1765
but3m1d + O = but3m1dp + OH
1.93 105
2.7
3716
f
1766 1767
but3m1d + H = but3m1dp + H2 but3m1d + OH = but3m1dp + H2O
1.88 105 1.05 1010
2.8 1
6280 1590
f f
1768
but3m1d + HO2 = but3m1dp + H2O2
1.68 1013
0
20440
f
1769
but3m1d + CH3 = but3m1dp + CH4
9.04 101
3.6
1770
but3m1dp = C4H6 + CH3
2.00 1013
1771
but3m1dp = C3H6 + C2H3
1772
1748
0 3250
f
0
7154
f
0
31000
f
2.00 1013
0
35500
f
isope + H = but3m1dp
1.00 1014
0
0
1773
but3m1dp + O2 = isope + HO2
7.50 1010
0
2500
1774 1775
but3m1dp + H = but3m1d C2H3 + C3H5-t = isope
1.00 1014 5.00 1013
0 0
0 0
1776
isope + OH = CH2O + iC4H7
1.37 1012
0
1040
o
1777
isope + OH = CH3CHO + C3H5-t
1.37 1012
0
1040
o
1778
isope + OH = CH3 + iC3H5CHO
1.37 1012
0
1040
o
1779
isope + OH = CH2O + C4H7-3
1.37 1012
0
1040
o
1780
isope + O = isopy + OH
1.74 1011
0.7
5900
f
1781
isope + H = isopy + H2
1.74 105
2.5
2510
f
1782 1783
isope + OH = isopy + H2O isope + HO2 = isopy + H2O2
3.00 106 9.60 103
2 2.6
298 13900
f f
1784
isope + CH3 = isopy + CH4
2.22 100
3.5
5670
f
1785
isopy = C3H4-a + C2H3
2.00 1013
0
50000
f
1786
isopy + HO2 = CH2O + iC4H5 + OH
4.50 1012
0
0
q
1787
isopy + H = isope
1.00 1014
0
0
estd.
4989
estd. n estd. estd.
dx.doi.org/10.1021/ef2012112 |Energy Fuels 2011, 25, 4986–4998
Energy & Fuels
ARTICLE
Table 2. Continued number
reaction
A
n
Ea
notea
1788 1789
but2m-3 = but2m2d + H but2m-4 + O2 = but3m1d + HO2
1.50 1013 1.58 1012
0 0
37500 5000
f n
1790
but2m-3 + O2 = but3m1d + HO2
6.90 1011
0
5000
n
1791
but2m-3 + O2 = but2m2d + HO2
4.50 1011
0
5000
n
a
Note: estd., estimated; (a) Black et al. Combust. Flame 2010, 157, 363373; (b) Dean et al. J. Phys. Chem. 1985, 89, 46004608; (c) Marinov Int. J. Chem. Kinet. 1999, 31, 183220; (d) Tsang J. Phys. Chem. Ref. Data 1988, 17, 887; (e) Wu et al. J. Phys. Chem. A 2007, 111, 66936703; (f) Touchard Ph.D. Thesis, Institut National Polytechnique de Lorraine, Nancy, France, 2005; (g) Park et al. J. Chem. Phys. 2003, 118, 99909996; (h) Xu et al. Proc. Combust. Inst. 2007, 31, 159166; (i) Xu et al. J. Chem. Phys. 2004, 120, 65936599; (j) Johnson et al. Atmos. Environ. 2004, 38, 17551765; (k) Curran Int. J. Chem. Kinet. 2006, 38, 250275; (l) Hartmann et al. Ber. Bunsen-Ges. 1990, 94, 639645; (m) Natarajan et al. Proc. Int. Symp. Shock Waves 1982, 13, 834; (n) Battin-Leclerc Prog. Energy Combust. Sci. 2008, 34, 440498; (o) Heyberger et al. Combust. Flame 2001, 126, 17801802; (p) Tsang J. Phys. Chem. Ref. Data 1991, 20, 221273; (q) Stothard et al. J. Chem. Soc., Faraday Trans. 1990, 86, 21152119.
injectors, the reactants were diluted with nitrogen (
