Environmental Engineering Research

Korean Society of Environmental Engineers (대한환경공학회)
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DIESEL ENGINE NOx REDUCTION BY SNCR UNDER SIMULATED FLOW REACTOR CONDITIONS

  • Nam, Chang-Mo (Division of Health & Environmental Engineering, Yeungnam College of Science and Technology) ;
  • Kwon, Gi-Hong (Division of Health & Environmental Engineering, Yeungnam College of Science and Technology) ;
  • Mok, Young-Sun (Department of Chemical Engineering, Cheju National University)
  • Published : 2006.06.30
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Abstract

NOx reduction experiments were conducted by direct injection of urea into a diesel fueled, combustion-driven flow reactor which simulated a single engine cylinder ($966cm^3$). NOx reduction tests were carried out over a wide range of air/fuel ratios (A/F=20-40) using an initial NOx level of 530ppm, and for normalized stoichiometric ratios of reductant to NOx (NSR) of 1.5 to 4.0. The results show that effective NOx reduction with urea occurred over an injection temperature range of 1100 to 1350K. NOx reduction increased with increasing NSR values, and about a 40%-60% reduction of NOx was achieved with NSR=1.5-4.0. Most of the NOx reduction occurred within the cylinder and head section (residence time <40msec), since temperatures in the exhaust pipe were too low for additional NOx reduction. Relatively low NOx reduction is believed to be due to the existence of higher levels of CO and unburned hydrocarbons (UHC)inside the cylinder, and large temperature drops along the reactor. Injection of secondary combustible additives (diesel fuel/$C_2H_6$) into the exhaust pipe promoted further substantial NOx reduction (5%-30%) without shifting the temperature windows. Diesel fuel was found to enhance NOx reduction more than $C_2H_6$, and finally practical implications are further discussed.

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References

  1. Zelenca, P., Cartellier, W., and Herzog, P., 'Worldwide diesel emission standards, current experience and future needs,' Applied Catalysis B: Environmental 10, 3-28 (1996)
  2. Hug, H. T., Mayer, A. and Hartenstein, A., 'Off-highway exhaust gas aftertreatment; combining urea-SCR, oxidation catalysis and traps,' SAE paper 930363 (1993)
  3. Heimrich, M. J., 'Diesel NOx catalytic converter development: A review,' Transactions of the ASME, 118, 668-672 (1996) https://doi.org/10.1115/1.2822684
  4. Masuda, K., Tsujimura, K., Shinoda, K. and Kato, T., 'Silver-promoted catalyst for removal of NO from emission of diesel engines,' Applied Catalysis B: Environmental 8, 33-40 (1996) https://doi.org/10.1016/0926-3373(95)00051-8
  5. Nam, C. M. and Gibbs, B. M., 'Application of the Thermal DeNOx process to diesel engine DeNOx: an experimental and kinetic modeling study,' FUEL, 81, 1359-1367 (2002) https://doi.org/10.1016/S0016-2361(02)00025-X
  6. Nam, C. M. and Gibbs, B. M., 'Selective catalytic reduction of NO by hydrocarbons over Cu/Al2O3 catalysts,' Environmental Sciences, 4(4), 201-208 (2000)
  7. Lyon, R. K., 'Method for the reduction of the concentration of NO in combustion effluents using $NH_3$,' U.S. Patent No. 3,900,554 (1975)
  8. Arand, J. K., Palos, R., Muzio, L. J. and Sotter, J. G., 'Urea reduction of NOx in combustion effluents,' U.S. Patent No. 4,208,386 ( 1980)
  9. Lyon, R. K., 'Thermal DeNOx controlling nitrogen oxides emissions by a noncatalytic process,' Environmental Science and Technology, 21(3), 231-236 (1987) https://doi.org/10.1021/es00157a002
  10. Kimball-Linne, M. A. and Hanson, R. K., 'Combustion-driven flow reactor studies of Thermal DeNOx reaction kinetics,' Combustion and Flame, 64, 337-351 (1986) https://doi.org/10.1016/0010-2180(86)90150-1
  11. Miller, J. A. and Bowman, C. T., 'Mechanism and modeling of nitrogen chemistry in combustion,' Prog. Energy Combust. Sci., 15, 287-338 (1989) https://doi.org/10.1016/0360-1285(89)90017-8
  12. Kasuya, F., G larborg, P., Johnson, J. E. and Dam-Johansen, K., 'The Thermal DeNOx process: Influence of partial pressures and temperature,' Chem. Eng. Sci., 50(9), 1455 -1466 (1995) https://doi.org/10.1016/0009-2509(95)00008-S
  13. Miyamoto, N., Ogawa, H., Wang, J., Shudo, T. and Yamazaki, K., 'Diesel NOx reduction with ammonium deoxidizing agents directly injected into the cylinder,' International Journal of Vehicle Design, 16( 1), 71-79 (1995)
  14. Jodal, M., Neilsen, C., Hulgaard, T. and Ostergaard, K., 'Pilot-scale experiments with $NH_3$ and urea as reductants in SNCR of NO,' Proceedings of the Combustion Institute, 23, 237-243 (1990)
  15. Gullett, B. K., Bruce, K. R., Hansen, W. F. and Hofman, J. E., 'Sorbent/urea slurry injection for simultaneous $SO_2/NOx$ removal,' Environmental Progress, 11(2), 155-162 (1992) https://doi.org/10.1002/ep.670110225
  16. Caton, J. A. and Siebers, D. L., 'Comparison of NO removal by Cyanuric acid and by ammonia,' Combustion Science and Technology, 65, 277-293 (1989) https://doi.org/10.1080/00102208908924054
  17. Koger, S. and Bockhorn, H., 'NOx formation from ammonia, hydrogen cyanide, pyrrole and carprolactam under incinerator conditions,' Proceedings of the Combustion Institute, 30, 1201-1209 (2005)
  18. Miller, J. A. and Bowman, C. T., 'Kinetic modeling of the reduction of nitric oxide in combustion products by isocyanic acid,' International Journal of Chemical Kinetics, 23, 289-313 (1991) https://doi.org/10.1002/kin.550230403
  19. Duo, W., Dam-Johansen, K. and Ostergaard, K., 'Widening the temperature range of the Thermal DeNOx process: an experimental investigation,' Proceedings of the Combustion Institute, 23, 297-303 (1990)
  20. Heywood, J. B., Internal combustion engine fundamentals. McGraw-Hill Book Co, 461-669 ( 1988)
  21. Kjaergaard, K., Glarborg, P., Dam-Johansen, K. and Miller, J. A., 'Pressure effects on the Thermal DeNOx process,' Proceedings of the Combustion Institute, 26, 2067-2074 (1996)