International Scientific Journal


Two promising combustion modification approaches applicable to pulverized coal fired boilers are presented: "Oxygen-Enriched Combustion" (OEC) for NOx control and "Oxy-Combustion" (PC-OC) for CO2 capture. Oxygen-enriched air rather than air is used as an oxidizer in the OEC technology. Unlike flue gas treatment technologies, OEC directly impacts the NOx formation process by significantly reducing the conversion of coal bound nitrogen to NOx. Pilot-scale and full-scale tests have shown 20 to 30% NOx reduction from an optimized staged-air baseline. In addition to the overall cost competitiveness and the reduced capital requirements, other significant advantages of the O2-enriched technology vs. existing low NOx technologies are presented. The PC-OC technology is shown as a cost-effective technology for CO2 capture from existing or new coal-fired power plants. Pure oxygen diluted in recycled flue gases is used as an oxidizer. The process has been successfully demonstrated and extensively characterized at pilot-scale level (1.5 MWt). The tests have shown substantial benefits of the PC-OC technology, in terms of NOx reduction (60-70% from air-baseline), overall plant efficiency, etc. The cost effectiveness of this capture technology compared to competitive amine scrubbing technology was investigated. The cost of CO2 avoided was around $36/ton for the new PC-OC cases, about $48/ton on a retrofit PC-OC case, which is about 25 to 40% cheaper than the amine scrubbing system. Those numbers were calculated for sub-critical units and include the cost of CO2 compression up to 80 bar. .
PAPER REVISED: 2005-09-14
PAPER ACCEPTED: 2005-10-15
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  1. DOE Office of Fossil energy, URL:
  2. Mitchell, S.C., NOx in Pulverized Coal Combustion, Report No. CCC/05, IEA Clean Coal Center, UK, 1998.
  3. Wu, Z., NOx control for pulverized coal-fired power stations, Report No. CCC/69, IEA Clean Coal Center, UK, 2002.
  4. Zevenhoven, R., Kilpinen, P., Control of pollutants in flue gases and fuel gases, Picaset Oy, Espoo, ISBN 951-22-5527-8, 2001.
  5. Van Der Lans, R. P., Glarborg, P. and Dam-Johansen, K., Influence of process parameters on nitrogen oxide formation in pulverized coal burners, Prog. Energy Combust. Sci. Vol. 23, p. 349-377, 1997
  6. Bowman, C.T., Kinetics of Pollutant Formation and Destruction on Combustion, Prog Energy Combust Sci 1, 1975, pp. 33-45.
  7. Proceedings of the 6th International Conference on Technologies and Combustion for a Cleaner Environment, Oporto, Portugal, 2001.
  8. Sarofim, A. F., Pohl, J. H., Taylor, B.R., Strategies for Controlling Nitrogen Oxide Emissions during Combustion of Nitrogen-bearing fuels, Proceedings, 69th Annual Meeting of the AIChe, Chicago, IL, 1976
  9. Bose, A.C., Dannecker, K.M. and Wendt, J.O.L., Energ. Fuel, 1988, Vol. 2, p.301.
  10. Moore, K., Ellison, W., Fuel Rich Combustion, A low cost NOx control means for coal-fired plants, Proceedings, 25th International Technical Conference on Coal utilization & Fuel Systems, Clearwater, FL, USA, 2000
  11. Châtel-Pélage, F., Pranda, P., Perrin, N., Farzan, H., Vecci, S.J., Oxygen-enrichment for NOx control in coal-fired utility boilers, Proceedings, The 29th International Technical Conference on Coal Utilization & Fuel Systems, Clearwater, FL, USA, 2004.
  12. Farzan, H., Vecci S. J., Châtel-Pélage, F., Pranda, P., Bose, A.C., Pilot-Scale Evaluation of Coal Combustion in an Oxygen-Enriched Recycled Flue Gas, Proceedings, The 30th International Conference on Coal Utilization and Fuel Systems, Clearwater, FL, USA, 2005.
  13. Varagani, R., Châtel-Pélage, F., Pranda, P., Lu, Y., Chen, S., Rostam-Abadi M., Farzan H., Vecciand S. J., Bose A., Performance Simulation and Cost Assessment of Oxy-Combustion Process for CO2 Capture from Coal-Fired Power Plants, Fourth Annual Conference on Carbon Sequestration, Alexandria, VA, 2005.
  14. Office of Fossil Energy, US DOE, Market Based Advanced Coal Power Systems, DOE/FE-0400, May 1999.
  15. Gilbert/Commonwealth Inc., Clean Coal Reference Plants: Pulverized Coal Boiler with Flue Gas Desulfurization, DE-AM21-94MC311 66, 1995.
  16. Birkestad, H., Separation and Compression of CO2 in O2/CO2-Fired Power Plant, master thesis, Chalmers University of Technology, Sweden, 2002.
  17. Garrido, G.F., Perkins, A.S., Ayton, J.R., Upgrading Lime Recovery with O2 Enrichment, Proceedings, CPPA Conference, Montreal, 1981
  18. Sing, D., Croiset, E., Douglas, P. L., Douglas, M. A., Techno-economic study of CO2 Capture from an Existing Coal-Fired Power Plant: MEA Scrubbing vs. O2/CO2 Recycle Combustion, Energy Conversion and Management, 44(19), 3073-3091, 2003.
  19. Rao, A. B.; Rubin, E. S., A Technical, Economic and Environmental Assessment of Amine-Based CO2 Capture Technology for Power Plant, Greenhouse Gas Control, Environ. Sci. Technol., 2002; 36(20); 4467-4475.

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