旋流对冲锅炉烟煤低氮燃烧特性数值模拟

Numerical Simulation on Low NO_x Combustion of Bituminous Coal in a Swirl-opposed Firing Boiler

为研究烟煤在旋流对冲锅炉的燃烧特性,采用Fluent软件对396MW旋流对冲锅炉内烟煤燃烧进行模拟,并对炉内速度场、温度场、颗粒运动轨迹、O_2分布、CO_2分布及NO分布进行分析。结果表明:在炉膛下部有两个明显的涡流区域;主旋流燃烧器的内外二次风是旋流,在旋流燃烧器内部产生高温烟气回流区;沿炉膛高度方向横截面上O_2和CO_2平均体积分数分布呈互补的关系。

To study the combustion characteristics of bituminous coal in swirl-opposed firing boilers, Fluent software was used to simulate the combustion of bituminous coal in a 396 MW swirl-opposed firing boiler, after which, analyses were conducted on the velocity field, temperature field, particle trajectory and the distribution of O2, CO2 and NO. Results show that there are two obvious vortex regions in the lower part of the furnace; both the internal and external secondary air flow in the pattern of swirling in the main swirl burner, which produce high temperature flue gas recirculation zone in the swirl burner. The average content of O2 and CO2 presents complementary relationship along the furnace height.