Experimental and Numerical Simulation Research on Different Shapes of Flame-Stabilizing Baffles in the Furnace

Abstract

The use of fully premixed combustion in small gas boilers can improve denitrification efficiency. On the basis of fully premixed combustion, adding flame stabilizers inside the boiler can further reduce production of oxides of nitrogen. Four types of flame-stabilizing baffles were added at a certain position inside the furnace after the fully premixed burner. Experiments were conducted separately on the Noporous baffle, and numerical calculations were performed for 36 operating conditions of the four baffles. The experimental results and numerical calculations indicate that under experimental conditions, NOx emissions were all below 40 mg/m3, and the net heat efficiency of the boiler was above 80%. Under a maximum firing rate, CO emissions are below 20 ppm, and the minimum error between the calculated and experimental values is 2.2%. The calculation error of CO emissions under various working conditions does not exceed 6.8%, indicating that the impact of different-shaped baffles on CO emissions is relatively small. When installing a Nonporous baffle, the error between the experimental and calculated exhaust temperature values under minimum firing rates is 6.6%, the error between the calculated and measured values under middle firing conditions is 2.9%, and the error between the calculated and measured values under maximum firing rate conditions is 3.0%. Among the four different partition conditions, the exhaust temperature of the Nonporous baffle is the lowest. Under the same excess air coefficient, the pressure in the furnace for the middle and maximum firing rate is higher than that of the minimum firing rate, and the experimental values are in good agreement with the calculated values. When installing the Strip baffle, the calculated CO2 emission is the lowest. The experimental results show that the NOx in the flue gas inside the furnace is mainly NO, and the NO content exceeds 75%, reaching a maximum of 85%. The experimental results show that the minimum NOx emission value is 26.9 mg/m3. The error between the measured and calculated NOx values when installing a Nonporous baffle is 20.4%. All of the above indicate that installing a flame-stabilizing baffle at an appropriate position in the furnace can further reduce NOx emissions, and the optimization amplitude is related to the shape of the baffle.