SPA-AA-TSS-PA-84-6
Technical Report
Reactivity of Methanol Exhaust:
A Smog Chamber Study
Project Officer: Craig A. Harvey
Technical Representative: Penny M. Carey
November 1984
NOTICE
Technical Reports do not necessarily represent final EPA
decisions or positions. They are intended to present
technical analysis of issues using data which are
currently available. The purpose in the release of such
reports is to facilitate the exchange 'of technical
information and to inform the public of technical
developments which may form the basis for a final EPA
decision, position or regulatory action.
Technical Support Staff
Emission Control Technology Division
Office of Mobile Sources
Office of Air and Radiation
U. S. Environmental Protection Agency
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Reactivity of Methanol Exhaust
Memorandum of Results
H.E. Jeffries, K.G. Sexton
R.M. Kamens, M.B. Holleman
Department of Envr. Sci. and Eng.
University of North Carolina
Chapel Hill, N.C., 27514
(919)-966-5451
A memorandum of results was furnished to the
Environmental Protection Agency by the University of North
Carolina, Department of Environmental Sciences and
Engineering, in fulfillment of Task Specification 22 of EPA
Contract No. 68-03-3162 with Southwest Research Institute.
This edited" version of the memorandum of results has been
released by EPA to report technical data of interest and to
facilitate information exchange. Readers should be aware
that the data reported here are preliminary. Detailed data
analysis will be performed and a complete report issued at a
later date.
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Reactivity of Methanol Exhaust
Memorandum of Results
September 26, 1984
Introduction
This memorandum summarizes the experimental results from a three month pro-
gram conducted in the University of North Carolina Outdoor Dual Smog Chamber.
The detailed experimental work has been described in a planning memorandum
(Jeffries, July 16), and two monthly progress reports (Jeffries et a/., July, August).
In addition, a half-day seminar was present by Jeffries at the EPA offices in Ann
Arbor.
Purpose of Work
The purpose of this research was to conduct outdoor smog chamber experiments
to test whether chemical mechanisms that are likely to be used in control strategy
calculations accurately predict the compositional effects caused by large scale use
of neet methanol as a fuel instead of gasoline.
The basic tests consisted of side-by-side experiments in which the chemistry of
a typical synthetic auto-exhaust or synthetic urban-like hydrocarbon mixture, at
typical HC-to-NO, ratios, was compared with the chemistry of a mixture in which
one-third of the original mixture is substituted by a synthetic methanol-exhaust
mixture. In these so called "substitution" experiments, the overall reactivity of
the original auto-exhaust mixture is compared with the reactivity of the methanol-
exhaust substituted mixture.
The tesis-««re conducted at four hydrocarbon (HC) concentrations: 0.6,1.0, 2.0,
and 3.0 parts per million Carbon (ppmC), and at 0.35 ppm oxides of nitrogen (NOX).
Substitution was-performed at the 1 and 3 ppmC level. The degree of substitution
was always 1:2 (33% substitution). The composition of the synthetic methanol-fuel
exhaust was 1% methyl nitrite (M«NOa), 0-20% formaldehyde (HCHO), and 79-99%
methanol (MeOH). The standard mixture was 10% formaldehyde.
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Coneluiloni
Conclusions
The major initial conclusions that can be drawn from this study are:
• Synthetic methanol exhaust substitution in these experiments never resulted in
an increase in reactivity, even for a fuel composition having 20% formaldehyde.
• At the 9-to-l HC-to-NOx ratio for the synthetic auto-exhaust, the synthetic
methanol exhaust is as reactive as the mixture; although the peak ozone is
essentially independent of the formaldehyde content, the rise of ozone is de-
layed slightly as formaldehyde is decreased from 20% (almost no delay) to 0%
(about 60 minutes delay).
• At the 3-to-l HC-to-NOx ratio for the synthetic auto-exhaust, there was a 33%
reduction in peak ozone when synthetic methanol exhaust containing 10% form-
aldehyde was substituted for 1/3 of the mixture.
• At the 9-to-l HC-to-NOx ratio, for the much less reactive synthetic urban mixture,
the synthetic methanol exhaust, at the 10% formaldehyde level, is as reactive
as the urban mixture; at the 0% formaldehyde level, however, there was a 17%
decrease in ozone maximum for a 33% substitution of methanol.
• At the 3-to-l ratio, for the synthetic urban mixture, there was also an 18%
decrease in peak ozone when methanol fuel (10% formaldehyde) was substituted.
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Summary of Results
Level of Effort
This project clearly met its goals in terms of producing quality experiments designed
to address the issue of methanol-exhaust reactivity:
1. Twenty-three dual smog chamber runs were conducted. Ten of these experi-
ments are nearly ideal for model testing, in close agreement with the estimates
made in the planning memorandum. The other 13 experiments, while having
poorer sunlight which complicates the model testing, are quite useful to support
the trends or directional effects of the substitution.
2. Three different hydrocarbon mixtures were used:
o UNCMDC, a well-studied paraffin and olefin mixture;
o SynAuto, a 13-component mixture developed by a series of direct com-
parisons of the mixture with automobile exhaust in side-by-side chamber
experiments; and (
o SynUrban, an 18-component mixture that conforms with the EPA rec-
ommended "default" mixture composition for use with the Carbon Bond
Model in urban ozone control calculations.
The composition of these mixtures is given in Table 1.
3. The composition of the synthetic methanol-fuel exhaust
was 1% methyl nitrite (MeNC>2) 0-20% formaldehyde
(HCHO), and 79-99% methanol (MeOH) . The standard
mixture was 10% formaldehyde.
4 . Three dual Experiments were conducted with UNCMIX; six dual experiments
were conducted with the SynUrban mixture; and 14 dual experiments were
conducted with the SynAuto mixture.
Experimental Results
Table 2 summarizes the major results for maximum Os produced. The dependence
of Os-maximum on HC at constant NOX is shown graphically in Figure 1. Profile
plots for NOX and 08 for four of the days are shown in Figures 2 -5.
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Summary of Result*
The SynAuto Runs
Table 2 shows that for the SynAuto mixture, the 3 ppmC pure SynAuto runs all
made approximately 0.8 to 0.9 ppm Oj. The variation is due to daily and monthly
variation in sunlight and temperature.
The 2 ppmC pure SynAuto run (Aug. 6) also made essentially the same Oj,
only a little later. The 1 ppmC pure SynAuto runs made a little more than half
the Oj of the 3 ppmC runs. The 0.66 ppmC run made about half the Os as that of
the 1 ppmC runs and about one-third the Oj of the 3 ppmC runs.
For the SynAuto substituted runs at the 3 ppmC level, the amount of Os pro-
duced was essentially the same as the pure SynAuto mixture; there was a small
dependence Oj rise time upon the amount of HCHO present in the methanol ex-
haust.
For the SynAuto substituted runs at the 1 ppmC level, there was a 33% re-
duction in maximum 03. This compares with a 42% reduction for simply removing
one-third of the carbon.
The SynUrban Runs
Table 2 shows that the SynUrban mixture is significantly less reactive than the
SynAuto mixture. At 3 ppmC pure SynUrban, the maximum Oj is approximately
equal to that in the 1 ppmC SynAuto run. At the 1 ppmC level, the SynUrban
ozone is less than 20% of the SynAuto ozone.
(
Substitution at the 3 ppmC level shows a small effect in 03 maximum and shows
a dependence upon the degree of formaldehyde substitution. Without formaldehyde
in the methanol exhaust, there was a 17% reduction in ozone maximum for a 33%
substitution.
Substitution at the 1 ppmC level also shows approximately the same effect: 18%
reduction in ozone maximum. Removing 1/3 of the carbon at this level, however,
has a very large effect on Oj production—a decrease of 80%.
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Table 1. Composition of Hydrocarbon Mixtures.
Compound
UNCMIX
SYNAUTO
SYNURBAN
butane
pentane
iaopentane
2-methylpentane
2,4-dimethylpentane
2,2,4-trimethylpentane
ethylene
propylene
1-butene
trans-2-butene
eia-2-butene
2-methyl-l-butene
2-methyl-2-butene
benzene
toluene
m-xylene
o-xylene
1 ,2,4- trimethy Ib enz ene
formaldehyde
total paraffin
total olefin
total aromatic
0.2531
0.1484
0.0996
0.0864
0.1202
0.1167
0.0524
0.0254
0.0313
0.0347
0.0317
0.7077
0.2922
0.0000
0.0391
0.0519
0.1121
0.2391
0.0416
0.0196
0.0196
0.0538
0.2115
0.1026
0.0481
0.0564
0.0200
0.2031
0.3199
0.4724
0.1000
0.1367
0.0801
0.0538
0.0467
0.0347
0.0630
0.0238
0.0137
0.0169
0.0187
0.0171
0.0331
0.1304
0.0633
0.0296
0.0347
0.0200
0.5404
0.1546
0.2854
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Table 2
Maximum Ozone for Methanol Reactivity Program.
(clear sky conditions only, units are ppm)
Initial HC. ppmC (mix/methanol)
Mixture
SynAuto
SynUrban
Jul25
Jul26
Aug 6
Aug 8
Aug 22
Sept 1
3
0.75
0.72
0.90
0.85
0.68
0.66
Jul26
Jul26
Aug 8
Aug 22
Sept 1
2/1
0.75 (10%)
0.72 (0%)
0.85 (20%)
0.65 (10%)
0.55 ( 0%)
2 1 0.6/0.3 0.6
Ang 6 AUK 6
0.55 0.32
Aug 7 Aug 7
0.60 0.40 (10%)
Aug 6
0.86
Aug 25 Aug 25
0.11 0.09 (10%)
Sept 2 Sept 2
0.11 0.02
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a
0.
u
a
o
N
O
Maximum Ozone in Mix Runs
(ppm 03)
rto
SynUrban
HC, PpmC
MeOS/SynAuto
MeOH/SynUrb
Figure 1. Maximum ozone concentrations as a function of initial
hydrocarbon for SynAuto mixture (top line) and for SynUrban mixture
(bottom line). Individual points are for 33% methanol/HCHO substitution.
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Augfust 05, 1984
Experimental Data
8 9 1« 11 12 13 14 15 16 17 18
HOURS EOT
19
Figure 2a. NO, N02, 03 data for August 5, 1984 dual smog
chamber experiment. 1.19 ppmC (BLUE - dashed
Itne) vs a.83 ppmC (RED - solid line) SYNAUTOj
0.35 ppm NOx both sides.
8 9 1« 11 12 13 14 15 16 17 18 19
Figure 2b. Total Solar Radiation (solid line). Ultraviolet
Radiation (dashed line), Oewpolnt (both sides).
and Temperature data for August 5, 1984 dual smog
chamber experiment.
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1.4
•9,9
0.8
9.7
9.«
e.5
9.4
9.3
9.2
9.1
1 i ' i • i ' i
" Experimental Data
8 9 19 11 12 13 14 15 16 17 18
HOURS EDT
19
Figure 33. NO, N02, 03 data for August 6, 1984 dual smog
chamber experiment. 3.12 ppmC (BLUE - dashed
line) vs 2.16 ppmC (RED - solid line) SYNAUTO;
0.35 ppm NOx both sides.
i I i I i I i_L i I i
5 S 7 8 9 19 11 12 13 14 15 16 17 18 19
HOURS EDT
Figure 3b. Total Solar Radiation (solid line). Ultraviolet
Radiation (dashed line), Dewpolnt (both sides),
and Temperature data for August 6, 1984 dual smog
chamber experiment.
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•9,9
9.8
«.7
9.6
e.s
0.4
9.3
e.2
9.1
4 • i • i • i ' i • i ' i r • i • i • i • i •
Experimental Data August 07, 1984
NO
i.e
9.9
9.8
9.7
9.6
9.5
9.4
9.3
9.2
9.1
19 11 12
HOURS
13 14
EDT
15 16 17 18 19
Figure 4a. NO, N02, 03 data for August 7, 1984 dual smog
chamber experiment. Synthetic MeOH exhaust
substitution Into SYNAUTO. 1.19 ppmC (RED -
solid line) vs 0.76 ppmC (BLUE - dashed line)
SYNAUTO with 0.3 ppm MeOH, 0.030 ppm HCHO and
0.003 ppm MeONO; 0.35 ppm NOx both sides.
r-r
August 07, 1984
19 11 12 13 14
HOURS EDT
Figure 4b. Total Solar Radiation (soltd ltn«>. Ultraviolet
Radiation (dashed line), Dewpolnt (both sides),
and Temperature data for August 7, 1984 dual smog
chamber experiment.
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' ' ' I ' I ' I ' I ' I ' I ' I ' I
Augfust 08, 1984
Experimental Data
5 6 7 8 9 !• 11 12 13 14 15 16 17 18
HOURS EDT
19
Figure 5a. NO, N02, 03 data for August 8, 1984 dual smog
chamber experiment. Synthetic MeOH exhaust
substitution into SYNAUTO. 3.34 ppmC (BLUE -
dashed 1.l.ne> va 2.23 ppmC (RED - sofld line)
SYNAUTO with 0.79 ppm MeOH, 0.2 ppm HCHO and 0.01
ppm MeONO; 0.35 ppm NOx both sides.
1111
Augfust 08, 1984 ^
TSR
9 19 11 12 13 14 15 16 17 18 19
HOURS EOT
figure 5b. Total Solar Radiation (solid line). Ultraviolet
Radiation (dashed line), Dewpotnt (both sides),
and Temperature data for August 8, 1984 dual smog
chamber experiment.
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