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Show - 18 - 5. Much lower NOx emissions were obtained in the reburn zone of the IPFR at a given Aeff when compared to the reburn zone of Furnace No. 1. The more efficient NOx in the IPFR was attributed to shorter convective, turbulent diffusion and reaction mixing times. 6. The TVFN concentration in the reburn zone experiments laboratory reactor were very similar to the NOx emissions in Furnace no. 1 for both coal and natural gas reburn fuels. This suggested that NOx reduction by reburning may be limited by the reconversion of HCN and NH3 to NOx in the reburn and tertiary combustion zones. Acknowledgements The authors would like to acknowledge that the work described in this paper was executed on behalf of and supported fmancially by organizations in Canada, the Federal Republic of Germany, the Netherlands and the United Kingdom. The programme has been organized under the auspices of the International Energy Agency and forms part of the Annex II of the implementing agreement for a programme of research, development and demonstration of coal combustion sciences. The authors would like to thank the Joint Committee of the IFRF for permission to present this paper. References 1. J ANDO Review of Japanese NOx control technology for stationary sources. in Air Pollution by Nitrogen Oxides, eds. T Schneider and L Grant, Elsevier, Amsterdam, 1982. 2. K J KNILL and M E MORGAN The effect of process variables on NOx and nitrogen species reduction in coal fuel staging. 1989 Joint Symposium on Stationary Combustion NOx Control, San Fransisco, March 6-9, 1989. 3. Y TAKAHASHI et al Development of Mitsubishi "MACT" In-furnace NOx removal process; Presented at US-Japan NOx Information Exchange, Tokyo, May 25 - 30, 1981. 4. S L CHEN, J M McCARTHY, W D CLARK, M P HEAP, W R SEEKER and PWPERSHING Bench and pilot scale process evaluation of reburning for in-furnace NOx reduction. Twenty-fust Symposium (International) on Combustion, The Combustion Institute, pp 1159-1169, 1986. 5. N OKIGAMA, Y SEKIGUCHI, Y MIURA, K SASAKI and R TAMARU Three staged pulverized coal combustion systems for in-furnace NOx reduction. Presented at Symposium on NOx control from stationary sources, Boston, May 6 - 9, 1985. 6. S MIY ANNAB, H IKEBE and K MAKINO Evaluation of in-furnace NOx reduction; Presented at Symposium on NOx control from stationary sources, Boston, May 6 - 9, 1985. |