NEXTLAB Conference, 2-4 April 2014 Online gas monitoring by using Raman spectroscopy Yamina OUABBAS H. Lucas 2, J. P. Viricelle 1, S. Grimaldi 3, B. Allard-Breton 3 1 Ecole Nationale Supérieure des Mines, SPIN-EMSE, CNRS: UMR5307, LGF, Saint-Etienne, France 2 Kaiser Optical Systems, Ecully, France 3 Arkema, Centre de Recherche Rhône-Alpes, F-69493 Pierre Bénite, France 1
Context of the study INNOVAL Project: Microanalysis of gas phase Context: Development of new NeSSI TM standard Our activity in the project : - Evaluation of existing NeSSI compatible analysers µgc, Raman, Hydrogen sensor - Trace analysis by µgc : micropreconcentrator development 2
INNOVAL Project: Microanalysis of gas phase Test bench development : requirements Gas : Air, N2, CO, CO2, H2, CxHy,. Flow : 0 à 10 L/h Temperature : ambiant up to 200 C Pressure : 1 to 10 bars Isobar ASTUTE Column 3
INNOVAL Project: Microanalysis of gas phase EMSE test bench : Gas mixer Heated sampling line Capteurs Vapor generator Mass flow meters Astute column 4
INNOVAL Project: Microanalysis of gas phase EMSE test bench : Génération vapeur d eau Capteurs Evaluation of Raman probe 5
Raman Spectroscopy: concept and theory Inelastic scattering of light with a material One in 10 7 photons is scattered inelastically Rayleigh scattering (elastic) Energy transfer Stokes scatteringanti-stokes scattering Raman spectrum 6
Raman Spectroscopy: concept and theory Only back scattered photons are collected Only Raman photons are simultaneously detected on CCD detector Notch filtering out original laser light Simultaneous detection through HoloPlex Grating CCD Detector HoloPlex Notch Filter Grating Laser light of specific wavelength (Rayleigh scattering) Wavelength shifted light (Raman scattering) 7
Raman probe / gas cell Rxn4 TM gas phase analyser with AirHead TM Raman probe/ gas cell system (Kaiser Optical System) (1) Raman probe-gas cell system. 1.optical fiber; 2. laser indicator light; 3.Raman head; 4.Focusing optics; 5.Sample zone; 6.Gas cell; 7.Laser beam; 8. Sapphire window; 9.Reflector - Excitation: 532 nm Laser. Power ~100 mw - Spectral range: ~ 150 cm -1 4350 cm -1 - Optical fiber length: 5 m (1) N. Taquet et al.; International Journal of Greenhouse Gas Control; 2013, 12, 359-371 NeSSI adaptation of Raman probe 8
Arkema application Forane (66%), CO (6.6%), CO 2 (6.6%), O 2 (1.3%), H 2 O, bal. N 2 Experimental conditions - Flow rate: 10 NL/h - Carrier gas : N 2 - Gas matrix :1,1,1,2-tetrafluoroethane (Forane) - Ambient temperature - Atmospheric pressure Tests: Calibration tests : 5 single gas (%vol) - Forane: 2% to 95% in N 2, - O 2 : 0.2% to 1.33% in 33% Forane in N 2, - CO, CO 2 : 0.2% to 6 % in 33% Forane in N 2, - H 2 O: 0.2% to 1% in 60% Forane in N 2 Predictions : Gas mixtures in 60% Forane in N 2 analysis : - 0.3% CO 2-0.3% CO-0.3% O 2 -(0.3, 0.5, 0.8 and 1)% H 2 O, - 0.5% CO 2-0.5% CO-0.5% O 2 -(0.3, 0.5 and 0.8 )% H 2 O, - 0.8% CO 2-0.8% CO-0.5% O 2 -(0.3, 0.5 and 0.8 )% H 2 O Mass flow meter Saturator Astute column EMSE Gas test bench 9
Raman spectrum example : Gas identification - 0.8% CO 2-0.8% CO - 0.5% O 2-0.8 % H 2 O in 60% Forane in N 2 Forane Raman peak reference (sapphire window): 772 cm -1 Forane: 843 cm -1 N 2 : 2330 cm -1 CO 2 : 1388 cm -1 O 2 : 1554 cm -1 CO: 2140 cm -1 H 2 O: 3650 cm -1 10
univariable model (2%-95%) Forane in N 2 - acquisition time: 3 min Forane Intensity (a.u.) Raman peak reference (sapphire window): 772 cm -1 Raman shift (cm -1 ) 11
univariable model (2%-95%) Forane in N 2 - Linear regression (Forane peak area at 843 cm -1 / reference peak area at 772 cm -1 ) Forane Estimated error due to gas generation Forane % absolute error % 40 0.63 60 0.63 80 0.72 12
univariable model (0.2%-6%) CO 2 in 33% Forane in N 2 - acquisition time: 3 min CO 2 Intensity (a.u.) Raman shift (cm -1 ) 13
univariable model (0.2%-6%) CO 2 in 33% Forane in N 2 - Linear regression (CO 2 peak area at 1388 cm -1 / reference peak area at 772 cm -1 ) CO 2 Estimated error due to gas generation CO2 % absolute error % 4 0.1 0.2 0.08 14
univariable model (0.2%-6%) CO in 33% Forane in N 2 - acquisition time: 5 min CO Intensity (a.u.) Raman shift (cm -1 ) 15
univariable model (0.2%-6%) CO in 33% Forane in N 2 - Linear regression (CO peak area at 2140 cm -1 / reference peak area at 772 cm -1 ) CO 16
univariable model (0.2%-1.33%) O 2 in 33% Forane in N 2 - acquisition time: 5 min O 2 Intensity (a.u.) Raman shift (cm -1 ) 17
univariable model (0.2%-1.33%) O 2 in 33% Forane in N 2 - Linear regression (O 2 peak area at 1554 cm -1 / reference peak area at 772 cm -1 ) O 2 18
univariable model (0.2%-1 %) H 2 O in 60% Forane in N 2 - acquisition time: 10 min H 2 O Intensity (a.u.) Raman shift (cm -1 ) 19
univariable model (0.2%-1%) H 2 O in 60% Forane in N 2 - Linear regression (H 2 O peak area at 3650 cm -1 / reference peak area at 772 cm -1 ) H 2 O Estimated error due to gas generation H20: absolute error % 0.8 0.1 0.4 0.05 0.2 0.03 20
Prediction Gas mixtures in 60% Forane matrix in N 2 - acquisition time : 10 min 0.3% CO 2 0.3% CO 0.3% O 2 (0.3, 0.5, 0.8, 1) %H 2 O 21
Prediction Gas mixtures in 60% Forane matrix in N 2 - acquisition time : 10 min 0.3% CO 2 0.3% CO 0.3% O 2 (0.3, 0.5, 0.8, 1)% H 2 O %H 2 O 0,3%H 2 O 0,5%H 2 O 0,8%H 2 O 1%H 2 O Forane-reg (%) 58,99±0,68 59,41±0,30 59,10±0,66 59,51±0,20 CO2-reg (%) 0,27±0,10 0,31±0,06 0,29±0,03 0,32±0,08 CO-reg (%) 0,39±0,17 0,33±0,08 0,35±0,02 0,31±0,02 O 2 -reg (%) 0,27±0,08 0,30±0,10 0,25±0,02 0,28±0,06 H 2 O-reg (%) 0,27±0,05 0,50±0,04 0,80±0,04 0,98±0,06 H 2 0 abs. gen. error 0.03 0.05 0.1 Abs. Generation error 0.6 % 0.1 % 0.1 % 0.1 % 22
Conclusions The ability of Raman spectroscopy for gas analysis has been demonstrated by using AirHead TM Raman probe-kaiser Optical System, This system allows the continuous measurement of gases (CO 2, CO, O 2 ) and H 2 O vapor in Forane matrix, Good correlation has been obtained for each gas calibration, but in the case of Forane, a nonlinearity was observed for low concentrations (<10%) underestimation (~1%) at 60% Good precisions (<10% rel.) have been obtained for each gas concentration in Forane matrix. A test bench equipped with an Astute column is available to evaluate various gases / Instruments 23
Acknowledgements
Thanks for your attention! CONFIDENTIEL
Analysis with and without mirror- Kaiser probe - 532 nm Intensity multiplied by ~4 with the amplification (mirror)
Prediction Gas mixtures in 60% Forane matrix in N 2 - acquisition time : 10 min 0.5%CO 2 0.5%CO 0.5%O 2 (0.3, 0.5, 0.8)%H 2 O 19
Prediction Gas mixtures in 60%Forane matrix in N 2 - acquisition time : 10 min 0.5%CO 2 0.5%CO 0.5%O 2 (0.3, 0.5, 0.8)%H 2 O %H 2 O 0,5%H 2 O 0,3%H 2 O 0,8%H 2 O Forane-reg (%58,41±2,79 59,42±1,16 59,26±0,32 CO 2 -reg (%) 0,60±0,11 0,53±0,06 0,54±0,08 CO-reg(%) 0,50±0,46 0,50±0,16 0,54±0,07 O 2 -reg (%) 0,62±0,34 0,51±0,09 0,53±0,05 H 2 O-reg (%) 0,46±0,03 0,27±0,06 0,78±0,02 20
Prediction Gas mixtures in 60% Forane matrix in N 2 - acquisition time : 10 min 0.8%CO 2 0.8%CO 0.5%O 2 (0.3, 0.5, 0.8)%H 2 O 23
Prediction Gas mixtures in 60% Forane matrix in N 2 - acquisition time : 10 min 0.8% CO 2 0.8% CO 0.5% O 2 (0.3, 0.5, 0.8)% H 2 O %H 2 O 0,8%H 2 O 0,5%H 2 O 0,3%H 2 O Forane-reg (%) 59,15±0,72 59,16±0,46 58,95±0,79 CO 2 -reg (%) 0,81±0,01 0,86±0,03 0,80±0,07 CO-reg (%) 0,85±0,06 0,82±0,16 0,86±0,19 O 2 -reg (%) 0,44±0,04 0,53±0,07 0,50±0,09 H 2 O-reg (%) 0,79±0,07 0,52±0,07 0,32±0,08 H 2 0 abs. gen. error 0.1 0.05 0.03 Abs. Generation error 0.6 % 0.1 % 0.1 % 0.1 % 24