| In the combustion process of the boiler,air is indispensable.In the air,nitrogen accounts for about 78%.Under high temperature conditions,nitrogen will react with oxygen to produce nitrogen oxides,causing environmental pollution.The structural design of natural gas low-nitrogen burners for boilers is mainly to control the combustion process,combustion environment and combustion conditions,and reduce the temperature of combustion flue gas to suppress the generation of NOx.First of all,based on the premise that the gas flow rate satisfies the normal combustion of the burner,the gas and combustion air are divided into two levels of supply,and the design is designed according to the ratio of the center gas and main gas flow rate 1/3,1/4,1/5 respectively The central gas pipe and the main gas pipe were designed with the core cylinder and its regulating module according to the ratio of primary air and secondary air at 22%.The effects of the gas concentration and oxygen concentration on the NOx emissions were verified by experiments to determine the best Gas supply structure.Then,according to the proposed overall structure,an axial straight blade swirler and a tangentially curved blade head swirler were designed.Under the same test conditions,the straight blade swirler and the tangentially curved blade Contrast experiments were carried out on the cyclone,and the effects on the success rate of ignition,flame stability,flame shape and combustion efficiency were verified,and the optimal type of cyclone on the burner head was determined.Finally,on the premise of ensuring the rated output of the burner,30%,35%,and 40% of the flue gas were introduced in the combustion zone respectively,and the performance test of the burner was conducted to study the influence of the concentration of flue gas participating in the combustion on the generation of NOx To determine the optimal percentage of flue gas recirculation. |
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