Status and analysis of NOx emission of district central heating gas boilers in Beijing

Measures NOx emission status of eighty-five gas boilers in Beijing. The test data show that average emission mass concentration of NOx is 125 mg/m3 and the NOx emission mass concentration of 25% of boilers is greater than 150 mg/m3. The effect of boiler load factor on NOx emission concentration is not obviously. With the excess air coefficient increases, NOx emission concentration firstly increases and then decreases. Boiler thermal efficiency and NOx emission concentration are antagonistic. To reduce the NOx emission of district heating gas boiler, recommends three techniques including low nitrogen burner, flue gas recirculation and selective catalytic reduction.