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Show 15/15 ii) N20 formation in the downstream region beyond the volatile matter combustion being finished is caused by not only the reaction triggered by the heterogeneous react i on of NO and carbon in char: NO + char-C -+ NCO to lead NCO + NO -+ N20 + CO, but also the direct reaction between nitrogen in char and NO: char-N + NO -+ N20. iii) I n case of coa 1 s wi th low fue 1 rat i 0, the N20 conyers i on decreases beca use of hi gh frame temperature surroundi ng the coa 1 part i c 1 es due to strong volatile matter combustion. Additionally the H radical produced by the oxidation reaction of CO also contributes to decomposing N20 near the particle surface. iv) The exit N20 concentration increases with the decrease of combustion efficiency, this is generally observed in case of burning coals of higher fuel ratio. REFERENCES 1) Ibusuki, T.: Nenryo Kyokai-shi, 68, 3, 190-199(1989) 2) Levine, J.S.: Proc. of the 5th Intl. Workshop on Nitrous Oxide Emissions, 1-10(1992) 3) Aho. M. and J.T. Rantanen: Fuel, 68, 586-590(1989) 4) Amand, L.E. and B. Leckner: Combus. Flame, 84, 181-190(1991) 5) Kramlich, J.e., J.A. Cole, J.M. McCarthy and W.S. Laniar: Combus. Flame, 77, 375-384(1989) 6) L i nak, W. P. : US Envi ronmenta 1 Protect i on Agency, Report, EPA-600/9-89- 062b(1990) 7) Aho, M.J., J.T. Rantanen and V.L. Linna: Fuel, 69, 8, 957-961(1990) 8) Muzio, L.J., M.E. Teague, J.e. Kramlich, J.A. Cole, J.M. McCarthy and R.K. Lyon: JAPCA, 39, 287-293(1989) 9) Muzio. L.J., G.S. Samuelsen, J.C. Kramlich, R.K. Lyon and A. Kokkinos: Proc. of the 23rd Symp. (I nt 1.) on Combus., 245-250( 1991 ) 10) Smart, J.P., P.A. Roberts and G.G. de -Soete: J. Inst. Energy, 63, 131-135(1990) 11) Suzuki, Z. and H. Moritomi: Nenryo Kyokai-shi, 69, 12, 1146-1151(1990) 12) Shimizu, T., D. Fujita, K. Ishizu, S. Kobayashi and M. Inagaki: Proc. of the 12th Intl. Conf. on Fluidized Bed Combustion, 611-615(1993) 13) Yamamoto, Y., Y. Itoh, J-W. Yuan, I. Naruse and K. Ohtake: Trans. of Japan Soc. of Mech. Eng., (Series B), 59, 564, 2560-2567(1993) 14) Naruse, 1. M. Imanari, K. Koizumi, J-W. Yuan and K. Ohtake: Kagaku- Kogaku Ronbunshu, 20, 2, 178-185(1994) 15) Kuramoto, K., K. Koi zumi, M. Imanari, I. Naruse and K. Ohtake: KagakuKogaku Ronbunshu, 20, 4, 482-4-88(1994) 16) Naruse, I., Y. Yamamoto, M. Imanari, J-W. Yuan and K. Ohtake: Proc. of the 24th Symp. (Intl.) on Combustion, 1415-1420(1992) |