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The importance of two sources of NO formation, nitrogen in combustion air and nitrogen in the fuel, during black liquor combustion was studied using a laminar entrained flow reactor. Pyrolysis and combustion experiments were conducted in nitrogen atmosphere and in a mixture of argon and helium in the composition 99% argon, 1% helium. The experiments were performed at three different temperatures: 700, 900, and 1100��C and at two residence times: 0.6 and 1.6 seconds. The results indicated that there was NO formation from the combustion air which was found to be prompt NO. There was NO formation from combustion air at all temperatures, and it decreased as temperature increased. Depending on conditions, prompt NO formation accounted for 6-80% of the total NO formation. NO reduction experiments were conducted to investigate the effect of molten sodium carbonate on NO reduction. The experiments were performed at two different temperatures, 800��C which is lower than the melting point of sodium carbonate and 900��C which is higher than the melting point of sodium carbonate. The rate constant for NO reduction was calculated and was found to agree well with that obtained in a previous study. The effect of the molten sodium carbonate on NO reduction was found to be negligible during black liquor pyrolysis. The rate in absence of any reducing gas components could explain NO reduction during black liquor combustion only to a limited extent. Models for nitrogen evolution during pyrolysis and combustion were developed by using data from previous studies. A model for nitrogen release during pyrolysis was developed as a function of residence time and temperature. Nitrogen release during pyrolysis was also found to be directly proportional to carbon release and the rate of nitrogen evolution with respect to the rate of carbon evolution decreased as temperature increased. / Graduation date: 1997

Bibliography: 208-218.

Bibliography: 208-218. / 339 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemical Engineering, 1989