天然气工业炉低氮燃烧技术研究与应用

Research and Application of Low Nitrogen Combustion Technology in Natural Gas Industrial Furnace

随着国家对环境质量的要求愈加严格,现有的天然气工业炉NOx排放水平已无法满足要求,研究和开发更加高效的低氮燃烧技术是实现燃气低氮排放的关键。文章从天然气燃烧NOx排放机理入手,分析现有的低燃燃烧技术,发现:热力型NOx占氮氧化物生成量的90%以上,快速性氮氧化物的生成量不足整体的10%;火焰峰值温度低于1500℃时,可认为不再产生热力型NOx;过量空气系数大于1便不再有快速性NOx生成。针对更加严格的排放标准,依靠单一技术缺点明显,无法满足当前的需要,技术间相互耦合是目前的发展趋势。烟气内循环技术因其通过燃气卷吸后部烟气,使得炉膛温度更加均匀,避免局部高温等优点,可以有效抑制热力型NOx产生,因此提出燃料分级耦合烟气内循环作为实现天然气超低氮排放的技术路线。

As China’s requirements for environmental quality become more and more stricter,the NOx emission of natural gas from industrial furnaces can no longer meet the requirements.Research and development of more efficient low-nitrogen combustion technologies is the key to achieve low-nitrogen emissions from natural gas.This article starts with the NOx emission mechanism of natural gas combustion and analyzes the existing low-combustion combustion technology.It is found that thermal NOx accounts for more than 90%of the production of nitrogen oxides,and the production of rapid nitrogen oxides is less than 10%of the total;flame peaks when the temperature is lower than 1500℃,it can be considered that no thermal NOx is produced;the excess air coefficient is greater than 1,and no rapid NOx is produced.In view of more stringent emission standards,relying on a single technology has obvious shortcomings and cannot meet current needs.Coupling between technologies is the most promising technology.Because the flue gas internal circulation technology uses gas to entrain the rear flue gas,it makes the furnace temperature more uniform and avoids local high temperature.It can effectively suppress the generation of thermal NOx.Therefore,it is proposed that the fuel staging coupled flue gas internal circulation is to achieve ultra-low natural gas effective technical route for nitrogen emissions.