摘要
烟气回流是实现柔和燃烧的手段,为精确控制回流比例,建立了分级燃烧器,实验研究了回流比例、当量比对CH4柔和燃烧火焰形态和NO、CO排放的影响。当量比为0.8,回流比例为0.6～0.7时实现柔和燃烧,反应区分散不分层,烟气中NO和CO体积分数分别小于1.2×10-5和4×10-5;回流比例过小时发生扩散燃烧,过大时燃烧不稳定;NO排放主要在烟气发生区产生。回流比例为0.6、当量比为0.6～0.8时,射流和主流有效掺混并伴有火焰抬升,实现柔和燃烧;相同当量比时,分级燃烧的NO排放较旋流扩散低,当量比0.8时,分级燃烧相对旋流扩散减排NO达44%。
Gas recirculation is a fundamental requirement for the establishment of MILD scheme. An axially-staged combustor for gas reeirculation ratio carefully modulating was experimentally studied to examine the effect of gas recireulation ratio and equivalence ratio on methane MILD flame characteristic and NO/CO emissions. At the equivalence ratio of 0. 8 and gas recirculation ration in the range of 0. 6 to 0. 7, MILD mode is realized with the characteristics of widely distributed reaction zone and NO/CO emissions lower than 1.2/ 4 × 10^-5 respectively. While the gas recirculation ratio is quite low, diffusion flame with concentrated flame front is observed; while the gas recirculation ratio is extremely high, the flame is unstable. At the gas recireulation ratio of 0. 6 and equivalence ration in the range of 0.6 to 0. 8, recireulated gas is efficiently mixed with secondary fuel and air, and MILD scheme is established. At the same equivalence ratio, NO emission from staged combustion is lower than that from diffusion combustion. At equivalence ratio of 0. 8, the former is lower than the latter by 26%.
出处
《燃气轮机技术》
2013年第1期33-39,共7页
Gas Turbine Technology
基金
国家自然科学基金(51006104)
关键词
分级燃烧
NOx
柔和燃烧
扩散燃烧
甲烷
staged combustion
NOx
MILD combustion
diffusion combustion
methane
