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© TDL Sensors Ltd 2012
Tunable Laser Gas Monitoring
© TDL Sensors Ltd 2012
 Very high sensitivity - ppt, ppb, ppm concentrations
 Measure the gas you want without interfere...
© TDL Sensors Ltd 2012
Based upon high-resolution
laser spectroscopy
Tunable Laser Gas Monitoring
© TDL Sensors Ltd 2012
Tunable Laser Gas Monitoring
Mid IRNear IRUV-Vis Visible
© TDL Sensors Ltd 2012
0.7-2.7 µm
Laser diodes, VCSELs
3-5 µm 4.2->12 µm
DFGs
QCLs
Tunable Laser Gas Monitoring
We use the...
© TDL Sensors Ltd 2012
Tunable Laser Gas Monitoring
NIR Mid-IR
Each gas
absorbs light in
a characteristic
way.
Hydrogen Fl...
© TDL Sensors Ltd 2012
Tunable Laser Gas Monitoring
Tunable
laser
Photodetector
I0
Beer - Lambert Law:
 L
I
I
T )(exp)(
...
© TDL Sensors Ltd 2012
Laser wavelength is tuned rapidly – no photodetector filters
Spectra are recorded 1000s of times pe...
© TDL Sensors Ltd 2012
Full spectrum analysis performed
Powerful pattern recognition signal processing methods used
Absolu...
© TDL Sensors Ltd 2012
Tunable Laser Gas Monitoring
Extractive gas analyser multipass optical cell
© TDL Sensors Ltd 2012
Very long pathlengths can be
achieved using a laser
- 7.6 m standard
- 70 m enhanced
© TDL Sensors Ltd 2012
Sample gas stream is often measured at
atmospheric pressure
However, TDL can also measure at
reduce...
© TDL Sensors Ltd 2012
Advantage of measuring at reduced
sample pressure
© TDL Sensors Ltd 2012
Reduced sample pressure advantages
• Very specific measurement(s)
• Multi-gas measurements with one...
© TDL Sensors Ltd 2012
Example:
HCl 1 ppm
H2O 30 % Vol
emissions from a stack
Reduced sample pressure advantages
© TDL Sensors Ltd 2012
1010 mbarA
Pathlength = 760 cm, Temperature = 360 K
Reduced sample pressure advantages
-20 -10 0 +10
© TDL Sensors Ltd 2012
Peak widths narrow
Reduced sample pressure advantages
-20 -10 0 +10
100 mbarA
Pathlength = 760 cm, ...
© TDL Sensors Ltd 2012
Reduced sample pressure advantages
-20 -10 0 +10
1010 mbarA
Pathlength = 760 cm, Temperature = 360 K
© TDL Sensors Ltd 2012
Reduced sample pressure advantages
-20 -10 0 +10
100 mbarA
Pathlength = 760 cm, Temperature = 360 K
© TDL Sensors Ltd 2012
Reduced sample pressure advantages
-2 -1 0 +1 +2
1010 mbarA
Pathlength = 760 cm, Temperature = 360 K
© TDL Sensors Ltd 2012
Isolated HCl peak
- even in the
presence of high
humidity
-2 -1 0 +1 +2
100 mbarA
Reduced sample pr...
© TDL Sensors Ltd 2012
Isolated HCl peak
Can also access H2O peaks to
report dry gas conc
Reduced sample pressure advantag...
© TDL Sensors Ltd 2012
© TDL Sensors Ltd 2012
Technology
Contact
TDL Sensors Ltd
48 Grafton Street
Manchester M13 9XX
United Kingdom
Tel: +44 (0)...
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TDLTech Presentation 14

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TDLTech Presentation 14

  1. 1. © TDL Sensors Ltd 2012 Tunable Laser Gas Monitoring
  2. 2. © TDL Sensors Ltd 2012  Very high sensitivity - ppt, ppb, ppm concentrations  Measure the gas you want without interference from other gases  Large dynamic range - 5 orders of magnitude  Absolute measurements – no drift, no calibration, inherently linear  Real-time (10 Hz or faster response)  Very low maintenance  Does not wear out Advantages of laser based gas analysers: Tunable Laser Gas Monitoring
  3. 3. © TDL Sensors Ltd 2012 Based upon high-resolution laser spectroscopy Tunable Laser Gas Monitoring
  4. 4. © TDL Sensors Ltd 2012 Tunable Laser Gas Monitoring Mid IRNear IRUV-Vis Visible
  5. 5. © TDL Sensors Ltd 2012 0.7-2.7 µm Laser diodes, VCSELs 3-5 µm 4.2->12 µm DFGs QCLs Tunable Laser Gas Monitoring We use the IR spectral region for gas measurements Tunable lasers available within this region
  6. 6. © TDL Sensors Ltd 2012 Tunable Laser Gas Monitoring NIR Mid-IR Each gas absorbs light in a characteristic way. Hydrogen Fluoride (HF) Carbon Dioxide (CO2)Nitric Oxide (NO)Ammonia (NH3)Carbon Monoxide (CO)Methane (CH4)Water (H2O) This means that each gas has a unique spectrum or “fingerprint”.
  7. 7. © TDL Sensors Ltd 2012 Tunable Laser Gas Monitoring Tunable laser Photodetector I0 Beer - Lambert Law:  L I I T )(exp)( 0         Absorption coefficient PathlengthTransmission  I I0 Laser frequency tuned I Transmission Signal out Gas Gas in Gas out Measurement cell L
  8. 8. © TDL Sensors Ltd 2012 Laser wavelength is tuned rapidly – no photodetector filters Spectra are recorded 1000s of times per second Not affected by particulate attenuation or changes in mirror reflectivity Full spectrum analysis performed Powerful pattern recognition signal processing methods used Absolute concentration measured – no drifting like other techniques Tunable Laser Gas Monitoring
  9. 9. © TDL Sensors Ltd 2012 Full spectrum analysis performed Powerful pattern recognition signal processing methods used Absolute concentration measured – no drifting like other techniques Tunable Laser Gas Monitoring
  10. 10. © TDL Sensors Ltd 2012 Tunable Laser Gas Monitoring Extractive gas analyser multipass optical cell
  11. 11. © TDL Sensors Ltd 2012 Very long pathlengths can be achieved using a laser - 7.6 m standard - 70 m enhanced
  12. 12. © TDL Sensors Ltd 2012 Sample gas stream is often measured at atmospheric pressure However, TDL can also measure at reduced sample pressure
  13. 13. © TDL Sensors Ltd 2012 Advantage of measuring at reduced sample pressure
  14. 14. © TDL Sensors Ltd 2012 Reduced sample pressure advantages • Very specific measurement(s) • Multi-gas measurements with one laser • Enhanced stability • No liquid phase water • No gas sample stream drying required
  15. 15. © TDL Sensors Ltd 2012 Example: HCl 1 ppm H2O 30 % Vol emissions from a stack Reduced sample pressure advantages
  16. 16. © TDL Sensors Ltd 2012 1010 mbarA Pathlength = 760 cm, Temperature = 360 K Reduced sample pressure advantages -20 -10 0 +10
  17. 17. © TDL Sensors Ltd 2012 Peak widths narrow Reduced sample pressure advantages -20 -10 0 +10 100 mbarA Pathlength = 760 cm, Temperature = 360 K
  18. 18. © TDL Sensors Ltd 2012 Reduced sample pressure advantages -20 -10 0 +10 1010 mbarA Pathlength = 760 cm, Temperature = 360 K
  19. 19. © TDL Sensors Ltd 2012 Reduced sample pressure advantages -20 -10 0 +10 100 mbarA Pathlength = 760 cm, Temperature = 360 K
  20. 20. © TDL Sensors Ltd 2012 Reduced sample pressure advantages -2 -1 0 +1 +2 1010 mbarA Pathlength = 760 cm, Temperature = 360 K
  21. 21. © TDL Sensors Ltd 2012 Isolated HCl peak - even in the presence of high humidity -2 -1 0 +1 +2 100 mbarA Reduced sample pressure advantages Pathlength = 760 cm, Temperature = 360 K
  22. 22. © TDL Sensors Ltd 2012 Isolated HCl peak Can also access H2O peaks to report dry gas conc Reduced sample pressure advantages -2 -1 0 +1 +2 100 mbarA Pathlength = 760 cm, Temperature = 360 K
  23. 23. © TDL Sensors Ltd 2012
  24. 24. © TDL Sensors Ltd 2012 Technology Contact TDL Sensors Ltd 48 Grafton Street Manchester M13 9XX United Kingdom Tel: +44 (0)161 606 7289 info@tdlsensors.co.uk www.tdlsensors.co.uk

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