ANALYSIS OF ETHANOL IN THE EXHAUST GAS USING GAS ... · - Ethanol is well separated from other...
Transcript of ANALYSIS OF ETHANOL IN THE EXHAUST GAS USING GAS ... · - Ethanol is well separated from other...
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SUMMARY
• Context
•Testing facilities for alternative method
• Synthetic gas tests- Ethanol sample- Sample without ethanol- Ethanol in hydrocarbon mixture- Sample stability
• Methodology development- Retention time determination- Detector linearity- Limit of detection / quantification
• Vehicle tests- Chromatogram from ECE phase (vehicle with E22)- Round Robin Test results
• Conclusion
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CONTEXT
UNECE is conducting work on the harmonization of light duty testprocedure for homologation (WLTP-DTP).
The Additional Pollutants subgroup is responsible for the development of test procedures for pollutants not currently regulated includingmeasurement equipment and formulae for the measurement for light duty vehicles.
New gasoline fuels are containing substantial amounts of ethanol which is able to be present in the exhaust gas.
The reference way of collecting ethanol from the exhaust gas is based on the use of impingers (solubilisation in water).
The following approach is to propose an alternative technology using bags.
4TESTING FACILITIES FOR ALTERNATIVE METHOD
Preconcentrator Entech Model
7100A
CVSDilution tunnelDilution air
Bag measurement
GC HP 6890 Series
min0 10 20 30 40 50
pA
0
50
100
150
200
250
300
éthène
éthane
propène
propane
isobutane
isobutène+butène 1
1.3 butadiène
butane
2t butène
2c butène
isopentane
pentène 1
pentane
isoprène
2t pentène
2c pentène
2M pentane
3M pentane
hexène 1
hexane
benzène
iso-octane
heptane
toluène
octane éthyl-benzène
m&p xylènes
o xylène
nonane 135 TMB
124 TMB
décane
123 TMB
undécane
dodécane
Measurement of ethanol from bag
6SYNTHETIC GAS TESTS
• Ethanol sample
ZOOM
ETHANOL in NITROGEN
Ethanol in gas phase can be detected by FID
7SYNTHETIC GAS TESTS• Sample without ethanol
no peak detected at the response time of ethanol
ZOOM
AIR ethanol
ZOOM
NITROGEN ethanol
8SYNTHETIC GAS TESTS
37 HC mixture of 150ppb and ethanol in Nitrogen.No interfering peak in ethanol peak area.The peak of “ethanol” is well separated.
• Ethanol in hydrocarbon mixture
Ethanol peak
ZOOM
9SYNTHETIC GAS TESTS
• Sample stability
Successive analysis on the same sample collected in bag.No significant difference observed � No evolution of the samples.
0
500
1000
1500
2000
2500
T = 0 hour T = 1 hour T = 2 hours T = 3 hours
Are
a
100ppb / N2
500ppb / N2
1000ppb / N2
Gas exhaust
11METHODOLOGY PERFORMANCE CRITERIA
• Retention time repeatability
0
2
4
6
8
10
12
14
16
18
20
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Injection number
Tim
e (m
inu
tes)
Very good repeatability2 σ = 0,05 minutes
Ave. = 16,05 min
15.8
15.85
15.9
15.95
16
16.05
16.1
16.15
16.2
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Injection number
Tim
e (m
inu
tes)
Experimental conditions : different analysis of samples at different concentrations
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• Detector linearity
100 ppb
1000 ppb
500 ppb
Calibration curve of ethanol
100 ppb
500 ppb
1 ppm
y = 2294,9x + 13,634R2 = 1
0
500
1000
1500
2000
2500
0 0,2 0,4 0,6 0,8 1 1,2
Concentration (ppm)
Are
a
The graph shows a very good linearity of the FID.
Samples obtained from 1ppm Ethanol in Nitrogen bottle and pure Nitrogen using Horiba type GDC-01 dilutor.
METHODOLOGY PERFORMANCE CRITERIA
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• Limit of detection / quantification
Limit of Detection : LoD = avg. (noise) + 3 x std. dev. (noise)LoD = 60 + (3 x 60)
LoD = 240 ppb
Limit of Quantification : LoQ = 3 x LoD or LoQ = 10 x std. dev. (noise)
LoQ = 3 x 240 or LoQ = 10 x 60
LoQ = 720 ppb or 600 ppb
Noise = 60 ppb
The determination limits is based on the noise measurement (reference DIN32645).Also see WLTP-DTP-AP-02-01a: Definitions
We assumed that LoD and LoQ are low enough to measure ethanol with accuracy
METHODOLOGY PERFORMANCE CRITERIA
15VEHICLE TESTS ON CHASSIS DYNO
• Flex Fuel vehicle with E22
Example of emissions during ECE phase of NEDC cycle.
min0 10 20 30 40 50
pA
0
50
100
150
200
250
300
éthène
éthyne
éthane
propène
propane
isobutane
isobutène+butène 1
1.3 butadiène
butane
2t butène
2c butène
isopentane
pentène 1
pentane
isoprène
2t pentène
2c pentène
2M pentane
3M pentane
hexène 1
hexane
benzène
iso-octane
heptane
toluène
octane
éthyl-benzène
m&p xylènes
o xylène
nonane
135 TMB
124 TMB
décane
123 TMB
undécane
dodécane
Ethanol
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• Round Robin Test results (3 labs / 1 vehicle)
These first results show a quite good correlation between the 2 methods
No significant difference on mean value including variability (σ/√n)
VEHICLE TESTS ON CHASSIS DYNO
Results comparison
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5
10
15
20
25
30
35
40
45
50
1 2 3 1 meanlab
mg/
km
impinger
bag
Laboratory Samplin g technology Analytical technology Ethan ol mg/Km
impinger GC 31,7
bag GC 26,4
impinger GC 32,0
bag GC 47,1
impinger GC na
bag GC 27,8
impinger GC 34,7
bag GC 34,9
ECE phase
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1
1
3
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- Feasability of analysis of diluted ethanol collected in bags using gas chromatography is demonstrated.
- Performance criteria
- Linearity of detector is confirmed.- Ethanol is well separated from other compounds present at the exhaust.
- LoD and LoQ are low enough to measure ethanol with accuracy.
- Ethanol stability in bag has been shown.
- Ethanol emissions can be analyzed and quantified according to the regulation.
- First results from RRT are very promising.
� Even if “impingers / GC” is the reference method, the proposed method could be considered as an alternative.
CONCLUSION