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NOx Overview
• What is NOx?
• Gas Turbine NOx
• Legislation
• Measurement• Measurement
• The future
• Questions
Images sourced
online [1]
What is NOx
• NO, NO2
• How is NOx formed?
• Thermal NOx
• Fuel Nox• Fuel Nox
• Prompt NOx9
• Zeldovich Mechanism
• O+ N2 ↔ NO + N
• O2 + N↔ NO + O
• N + OH ↔ NO + H
NOx emissions from GTsE
mis
sio
ns
• Smoke & NOx vs. CO &HC [2&3]
Nox
Smoke
Em
issio
ns
Idle Max. Power
COUHC
• Possible technical solutions [4] & [5]
– H2O/ Steam injection- 25ppm
– Selective Catalytic Reduction-9ppm
– Catalytic Combustion-3ppm
NOx Abatement Technologies
COOLER GAS– Catalytic Combustion-3ppm
– SCONOX-2ppm or less
– Dry Low NOx combustion-9ppm
CM56 5B Double Annular
Combustor [6]
[4] *1 sourced from (GE Energy 01)[5] *2 sourced from (Major 1999)
COOLER GAS
HOT GAS
Why Legislate against NOx?
• Photochemical Smog precursor- deaths,
respiratory problems
• Acid rain precursor[6]
• Nutrification & Ozone issues• Nutrification & Ozone issues
• Indirect green-house gas (GHG)
NOx Health Impacts
• Cardiopulmonary mortality
• Strokes, myocardial infraction
• Lung irritation, Bronchitis and Pneumonia
• $64-$315 health damage per ton of NOx in the USA [7&8]
Nitric Oxide (NO) Concentration Health Impact
Very Low Essential for human life
~50ppm Irritating to mucus membranes
60-150ppm Causes burning of throat and coughing
>200ppm Fatal to humans if exposed for short times
[6]
• $64-$315 health damage per ton of NOx in the USA
• EU Directive- 26ppm NOx
-1167kt permitted for UK NOx (during 2010) [9]&[10]
• US <2.5ppm NOx emissions from 300MW
stationary GTs (effective 2006)[11]
Current Legislation
stationary GTs (effective 2006)[11]
• UK NOx emissions
reduced by 40%
(1990-2006)[12]
Measurement Techniques
CL-1
0.2ppmFTIR-3
0.44ppm
DOAS-2
1-3ppb
Organic Sensors
0.01ppm
DFWM
2ppm
GT
tested
Measurement
Methods
CRDS
< 1ppm
SFG UV LA
0.5ppmTDLAS
< 1ppmLIF
5-10ppm
CARS
25ppm
DIAL
+/- 25% CL
ZirconiaProbes-5
0.5ppm
0.01ppm
Future Concerns- Biofuels
• Low grade biofuel effect on NOx emissions
from stationary GTs
– Fuel Nox reduced [13]
• Lower CV :. Lower temperature :. Less thermal Nox• Lower CV :. Lower temperature :. Less thermal Nox
Idle Power
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
UHC NOx CO CO2
Co
mp
are
d t
o J
et
A-1
GTL
50/50 Blend
Bio-diesel
Leong, Rye et al. 2010
Future Legislation &
Measurement Technology • Decrease/ Increase? Zero NOx Legislation?
• Many measurement technologies are less
sensitive than legislations in GT exhausts
– Current CL measurement precision (Standard NOx – Current CL measurement precision (Standard NOx
technique): 0.2ppm stated HOWEVER interference
of 3.6ppm from CO2 and water
• Higher accuracy measurement possibilities:
– FTIR?
– Stabilised Zirconia Probes?
References
1. Winter, M. (2009). "Web Elements." Retrieved 12/03/2010, 2010, from http://www.webelements.com/compounds/nitrogen/nitrogen_dioxide.html.
2. Lefebvre, A. W. (1983). Gas Turbine Combustion. Washington New York and London, McGraw Hill Book Company.
3. Ballester, J. and T. García-Armingol "Diagnostic techniques for the monitoring and control of practical flames." Progress in Energy and Combustion
Science In Press, Corrected Proof.
4. TLC, T. L. C. (2005). "Combustor technology: present and future." Retrieved 02/02/2010, 2010, from http://gfn.unizar.es/tlc/background.
5. Chaloulakou, A., I. Mavroidis, et al. (2008). "Compliance with the annual NO2 air quality standard in Athens. Required NOx levels and expected health
implications." Atmospheric Environment 42(3): 454-465.
6. Anderson, T. N. (2003). THE DEVELOPMENT AND APPLICATION OF A DIODE-LASER-BASED ULTRAVIOLET ABSORPTION SENSOR FOR NITRIC OXIDE.
Mechanical Engineering, Texas A&M University. Master of Science: 120.
7. Nigge, K. (2001). "Generic spatial classes for human health impacts, part II." The International Journal of Life Cycle Assessment 6(6): 334-338.7. Nigge, K. (2001). "Generic spatial classes for human health impacts, part II." The International Journal of Life Cycle Assessment 6(6): 334-338.
8. The European Parlieament and the Council of the European Union (2001). Directive 2001/81/EC of the European Parliament and of the Council: on
national emissions ceilings for certain atmospheric pollutants. Official Journal of the European Communities: 22-30.
9. The European Parlieament and the Council of the European Union (2001). "Driective 2001/80/EC of the European Parliament and of the Council."
Official Journal of the European Communities 175(1): L309/ 301 – 321
10. NAIE (2007). UNECE Emission Estimates to 2007: Nitrous Oxide.
11. California Energy Comission (2000). "Permit to Construct (Emissions Permit)." Retrieved 08/02/2010, 2010, from
http://www.energy.ca.gov/sitingcases/mountainview/documents/2000-11-02_PDOC.PDF.
12. GE Energy (2006). "Extractive FTIR Air Emissions Testing." Retrieved 08/02/2010, 2010, from
http://www.gepower.com/prod_serv/serv/env_serv/en/downloads/gea14569_ftir_techoverview.pdf.
13. Signal Instruments (2007). "Heated Vacuum Chemiluminescence Model 4000VM." Retrieved 05/02-2010, 2010, from
http://www.signalinstruments.com/4000vm.htm.
14. Horiba Automotive Test Systems (2010). "MEXA-720 NOx." Retrieved 08/02/2010, 2010, from http://www.horiba.com/automotive-test-
systems/products/emission-measurement-systems/portable-emission-analyzers/details/mexa-720-nox-860/.
15. Testo (2010). "Portable Flue Gas Analyzer System testo 350." Retrieved 03/02/2010, 2010, from
http://www.bis.fm/assets/documents/faxdatasheets/350%20XL_S%20brochure.pdf.
16. Leong C; Rye L; et al (2010). "Reverse Engineering: Gas Turbine Performance: Applied to an Aircraft Auxilliary Power Unit." Turbo Expo ASME
2010(GT2010-22478).
Worldwide NOx limits
Name of State/Union/ Federation Most Stringent NOx Emission Ceiling (ppmv)
@ 15% O2
USA (California) 2
Japan 5
USA (Federal Codes of Regulation) 15USA (Federal Codes of Regulation) 15
European Union 26
Canada 29
China 40
India 50
Brazil (Inferred from literature) 65
Russia and NIS 65
Israel N/A (building to EU standards)
The Kingdom of Saudi Arabia N/A