variavel0=<b>Pedro Teixeira Lacava</b> - lacava@aer.ita.br ITA
<b>Amilcar Porto Pimenta</b> - amilcar@aer.ita.cta.br ITA
<b>Marco Aurélio Ferreira</b> -  INPE
<b>João Andrade Carvalo Jr.</b> - joao@feg.unesp.br UNESP
<b>Abstract.</b> The advantages of air enrichment in combustion systems are: increase of productivity, high thermal efficiency, reduction of combustion gas volume, increase of operation temperature, intensification of heat transfer process and reduction of fuel consumption. However, due the high temperatures reached in the combustion chamber, the increase of NOx emission may be a problem in operation with enriched flame. In this way, the present work shows the result of an experimental investigation on the control of NOx emissions using staged combustion in an incineration chamber of liquid aqueous residues, operating with air enriched with oxygen and diesel oil as auxiliary fuel. First, some experiments were conducted without staged combustion to verify the increase of chamber incineration capacity as function of air enrichment and to evaluate the emissions gases behavior, mainly NOx. Both oxidant and fuel staged combustion experiments were conducted in an enrichment condition that promotes high normalized NOx emission (NO2 mass flow rate/ residue mass flow rate), 43,42% of O2. Fuel staged combustion reduced the NOx emission on 61% and, in the case of the oxygen injected 1,225m above de burner, the reduction was 88% for the oxidant staged combustion.
<b>Keywords.</b> combustion, NOx emission, staged combustion, enrichment, incineration.