Abstract
To optimize the structure of the burner, improve the combustion performance, and reduce the emission of NO
x
, a self-circulating low NO
x
combustion technology was used to design a new type of flue gas self-circulating low NO
x
burner. Based on previous research on the numerical model of combustion and the composition of mixed gas on combustion and NO
x
emissions, the effect of various factors on the ejection coefficient of the flue gas self-circulating structure was analyzed using the orthogonal test method, and the burner operating parameters, such as preheating temperature and excess air coefficient, were deeply studied through the three-dimensional finite element numerical model in this paper. The results show that the diameter ratio of the nozzle and the length of the cylindrical section of the flue gas self-circulating structure have great influence on its ejection and mixing ability. The optimal ejection coefficient was 0.4829. Overall, the amount of NO
x
emissions greatly increased from 6.23×10
−6
(volume fraction) at the preheating temperature 973 K to 3.5×10
−3
at preheating temperature 1573 K. When the excess air coefficient decreased from 1.2 to 1, the maximum combustion temperature decreased from 2036.3 K to 1954.22 K, and the NO
x
emissions decreased from 352.29×10
−6
to 159.73×10
−6
.