Concentrations of carbon monoxide and nitrogen oxides from a 15 kW heating boiler supplied periodically with a mixture of sunflower husk and wood pellets

The impact of periodic feeding mode on the concentrations of carbon monoxide (CO) and nitrogen oxides (NO, NOx) in the flue gas downstream the boiler was analyzed during firing of a mixture of sunflower husk and wood pellets in an overfeed furnace. The mixtures containing 100, 70 and 50 wt. %, of sunflower husk pellets were supplied to the boiler in two feeding modes: 1 s of operation 4 s of stand-by and 1s of operation 6 s of stand-by. Correlation between pollutant concentrations and the temperature in the combustion chamber was evaluated. The following concentrations of CO for various feeding modes and sunflower husk pellet proportions have been obtained: 1:6,100% - 6150 mg/m3,1:6,70% - 3360 mg/m3, 1:6, 50% - 2600 mg/m3, 1:4,100% - 4580 mg/m3,1:4, 70% - 2570 mg/m3, 1:4,50% - 870 mg/m3 for 10% O2 content in the flue gas. The study indicates the advisability of reducing the stand-by period in the pellet feeding system.