NOAA GMAC 2018 Open-Path Laser Dispersion Spectrometer for Methane - - PowerPoint PPT Presentation

Making Light Work

NOAA GMAC 2018 Open-Path Laser Dispersion Spectrometer for Methane Emissions Mapping and Quantification

Dr Graham Leggett VP, Business Development

OUTLINE

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1.

• 1. Abo

bout ut M MIRICO 2.

• 2. Tec

echno hnology

• Laser Dispersion Spectroscopy (LDS)

3.

• 3. Em

Emissions M Mappi pping a and nd Qua uantification

• CH4 release trials in collaboration with Shell Global

Solutions International B.V.

• Mapping derived using Shell LightSource software
• Collaboration with NPL

4.

• 4. Conclus

usions ns

ABOUT MIRICO

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• Developer of rugged, high performance spectrometers for gas analysis
• Space science technology developed at Rutherford Appleton Labs
• Instruments offer precision, sensitivity, accuracy, and reliability
• Headquarters in Oxford, UK

Robust Space Technology

Rugged & High performance Analysers for the field Serving Multiple Industries

LASER DISPERSION SPECTROSCOPY

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I0 It

• Signal encoded in intensity of

emitted beam

• Non linear after 10% absorbance
• Useful signal limited by intensity –

susceptible to dust, water vapour, etc.

• Signal encoded in phase of beam
• Linear response over broad dynamic range
• Maintains sensitivity in “dirty”

environments

• Immune to intensity fluctuations

ABSORBTION LDS

LASER DISPERSION SPECTROSCOPY

5 QCL/ICL Mid-infrared laser Acousto-optic modulator (AOM) Detector

• Each frequency experiences

different refracted index

• Results in different propagation

time to detector

Absorption LDS

SET-UP

6 LDS 1 100 OP OP prototyp ype CH CH4 Tr Tripod-mounted c corner cube re retro re reflector 500 m 500 m

• 1 km

km t tot

• tal

al p path-len ength ( (transmit a and return)

• Manual

al align gnmen ent using v g visible l e laser

• ~1

1 hour d dep eployment p t process ss

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SIMPLE CASE OF POINT EMITTER TEMPORAL EVOLUTION OF CH4

OPEN-PATH LDS – CH4 MAPPING

OPEN-PATH LDS – CH4 MAPPING

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SIMPLE CASE OF POINT EMITTER TEMPORAL EVOLUTION OF CH4

MULTI-PATH CH4 EMISSIONS MAPPING

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Laser AOM Fast galvo mirror Detector

MULTI-PATH CH4 EMISSIONS MAPPING

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• 19 releases of ~1 hour each
• 2x2m diffuse area sources at ground level
• four release schemes of 1 or 2 sources
• emission rates: 1.2 to 1.6 kg/hr per source
• <2m/sec wind -data excluded
• 1 minute data averaging used

MULTI-PATH CH4 EMISSIONS MAPPING

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MULTI-PATH CH4 EMISSIONS MAPPING

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Wind direction

Release Location 2

7 min background 7 min background 40 min release

             

Paths 5, 6, and 7 upwind so no reaction to release

 

Path switching 10 milliseconds ~200 meters 0-14 ppm

Temporal evolution of integrated CH4 concentration over 7 paths 1s resolution - ~10 ppb precision - ~1 ppm.m/√Hz (1 of 5 datasets used for analysis)

120 ms/beam

MULTI-PATH CH4 EMISSIONS MAPPING

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Location 1 1.35kg/hr actual Location 3&4 2x 1.24 kg/hr actual Location 2 1.38 kg/hr actual Location 3 1.47 kg/hr actual

NPL TRIAL

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Purpose: Test at different heights, emission scenarios and release rates.

NPL TRIAL

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CONCLUSIONS

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• Suc

Succes essfully t y tak aken LDS f S from l laboratory to fiel eld

• Co

Confirmed ed pa path th-leng ngth a and s nd sensitivity

• Co

Confirmed ed o

• per

perati tion in n variable a e atmosp spher eric condi nditions

• De

Demons nstrated s ed scanni nning ng techni hniqu que f for l large-area ea mapp pping ng

ACKNOWLEDGEMENTS

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THANK YOU

QUESTI TIONS? graham@mirico.co.uk +44 7715 676751 www.mirico.co.uk