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| Titel |
Fugitive methane emission pinpointing and source attribution using ethane measurements in a portable cavity ring-down analyzer |
| VerfasserIn |
Derek Fleck, John Hoffnagle, John Yiu, Johnston Chong, Sze Tan |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147251
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| Publikation (Nr.) |
 EGU/EGU2017-11384.pdf |
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| Zusammenfassung |
| Methane source pinpointing and attribution is ever more important because of the vast
network of natural gas distribution which has led to a very large emission sources. Ethane can
be used as a tracer to distinguish gas sources between biogenic and natural gas. Having
this measurement sensitive enough can even distinguish between gas distributors,
or maturity through gas wetness. Here we present data obtained using a portable
cavity ring-down spectrometer weighing less than 11 kg and consuming less than
35W that simultaneously measures methane and ethane with a raw 1-σ precision of
50ppb and 4.5ppb, respectively at 2 Hz. These precisions allow for a C2:C1 ratio 1-σ
measurement of <0.1% above 10ppm in a single measurement. Utilizing a second
onboard laser allows for a high precision methane only mode used for surveying and
pinpointing. This mode measures at a rate faster than 4Hz with a 1-σ precision of
<3ppb. Because methane seepages are highly variable due to air turbulence and
mixing right above the ground, correlations in the variations in C2H6 and CH4
are used to derive a source C2:C1. Additional hardware is needed for steady state
concentration measurements to reliably measure the C2:C1 ratio instantaneously.
Source discrimination data of local leaks and methane sources using this analysis
method are presented. Additionally, two-dimensional plume snapshots are constructed
using an integrated onboard GPS to visualize horizontal plane gas propagation. |
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