摘要
中度与极度低氧稀释(moderate or intense low-oxygen dilution,MILD)氧燃烧技术能同时实现低碳和超低NO_(x)排放,是一种创新性的燃烧技术。通过实验方法研究了不同稀释剂(N_(2)、CO_(2)和H_(2)O)、氧气浓度、当量比和氧化剂预热温度下甲烷非预混MILD氧燃烧和排放特性。实验发现,N_(2)、CO_(2)和H_(2)O稀释的所有工况中均没有观察到火焰。但N_(2)稀释时,炉内温度和NO排放都比较高,且当氧浓度、当量比或氧化剂温度增加时,NO排放急剧升高(>100×10^(-6)),因此无法实现较好的MILD氧燃烧。与之相比,CO_(2)或H_(2)O稀释下,炉内温度较低,NO排放也非常低(<10×10^(-6));并且NO排放对氧浓度、当量比和氧化剂温度的变化不敏感,能在更宽的范围内建立起低排放的MILD氧燃烧。此外,CO_(2)稀释时会产生较高的CO排放(>20×10^(-6)),但H_(2)O稀释下几乎没有CO排放,且NO排放最低(≈1× 10^(-6))。因此,H_(2)O稀释最有利于实现超低排放的MILD氧燃烧。但实际炉膛应用时需要注意防止H_(2)O稀释造成的炉壁汲水和因此导致的热效率降低、甚至熄火。
The moderate or intense low-oxygen dilution(MILD) oxy-combustion is an innovative technology of combustion,which can simultaneously realize low carbon and ultra-low NO_(x) emissions.This work experimentally investigated the combustion and emission characteristics of non-premixed MILD oxy-combustion firing methane under various oxidant conditions,such as diluent type,oxygen concentration XO_(2),equivalence ratio Φ and oxidant preheating temperature Tin.Results show that no flame is observed in all the investigated cases under N_(2),CO_(2) or H_(2)O dilution.However,when N_(2) is used as the diluent,the in-furnace temperature and the NO emission are very high,and NO emission increase abruptly(>100×10^(-6)) at higher XO_(2),Φ,or Tin.Thus,MILD oxy-combustion cannot be well established under N_(2) dilution.Relatively,under CO_(2) or H_(2)O dilution,the in-furnace temperature and the NO emission(<10×10^(-6)) are very low and not sensitive to the variations of XO_(2),Φ and Tin.Therefore,low emission MILD oxy-combustion can be realized in a wide range of oxidant conditions under CO_(2) or H_(2)O dilution.Moreover,the CO emission is high(>20×10^(-6)) under CO_(2) dilution,but it is nearly zero under H_(2)O dilution.The NO emission(≈1×10^(-6)) is also lower for the latter.Therefore,H_(2)O dilution is most beneficial for establishing ultra-low emission MILD oxy-combustion.Cautiously,when use H_(2)O dilution for practical application,the prevention should be made from the furnace wall absorbing water,which will reduce thermal efficiency and even make extinction to occur.
作者
王国昌
舒子云
司济沧
王勃
朱荣
米建春
WANG Guochang;SHU Ziyun;SI Jicang;WANG Bo;ZHU Rong;MI Jianchun(College of Engineering,Peking University,Haidian District,Beijing 100871,China;China Ship Development and Design Center,Wuhan 430072,Hubei Province,China;Beijing Municipal Office for Science and Technology Awards,Haidian District,Beijing 100444,China;School of Metallurgical and Ecological Engineering,University of Science&Technology Beijing,Haidian District,Beijing 100083,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2021年第18期6312-6320,共9页
Proceedings of the CSEE
基金
国家自然科学基金项目(51776003)。
