Reduction of nitrogen oxides in 46 MW oil heated furnace at Umeaa Energi

This report shows trials to reduce nitric oxide outputs from an 46 MW oil heated hotwater furnace. The trials have been accomplished at Umeaa Energi's district heating production plant in Umeaa, during the winter and the spring 1998. The furnace has four oil burners, situated in pairs above each other. With basis from their placing, the possibility of reaching a gradual combustion by redistributing the effect and the secondary air was studied. The main purpose was to see if anyone of the parameters had significance for the production of NOx, and in that case how much the discharge could be reduced. The results of the trials showed that only the lower secondary air had significance for production of NOx in the furnace. If the secondary air was redistributed from the lower pair of burners to the upper pair, the following reduction could be reached: (1) 10.9% NO2-reduction at a load of 70% maximum effect, (2) 9.8% NO2-reduction at a load of 80% maximum effect, and 9.8% NO2-reduction at a load of 90% maximum effect. At maximum NO2-reduction the dust content in the fumes was increased from 0 - 0.5% to 0.5 - 0.8%. The increase is not estimated as harmful and is assumed to depend on the oil burners, which are not adjusted to be operated for attaining low production of NOx Examination paper. 5 refs, 9 figs, 8 tabs, 7 appendixes