因固有的低污染物排放控制成本优势，循环流化床(CFB)锅炉已成为商业化程度最好的洁净煤燃烧技术之一。随着超低排放标准的提出，CFB燃烧技术也面临巨大挑战。为满足超低排放标准，通常要使用烟气净化处理装置，导致CFB锅炉污染控制成本显著增加。如何低成本实现CFB锅炉NOx与SO2原始超低排放成为关注焦点。系统论述了现有CFB超低NOx和SO2排放技术、最新开发的CFB超低NOx燃烧技术、炉内CFB超低SO2排放技术和CFB超低NOx、SO2协同控制技术等。研究表明：开发高效分离器不仅可提升CFB燃烧效率，也是保证超细石灰石高效脱硫的前提，分离器效率越高，CFB燃烧效率和超细石灰石脱硫效率越高；随着循环流化床锅炉的大型化发展，炉膛截面越来越大，如何实现超细石灰石在大型炉膛内横向的均匀混合成为第1个技术难点；控制单一气体使其满足超低排放的技术相对成熟，但如何协同控制NOx和SO2使之满足超低排放标准成为第2个技术难点；现阶段CFB炉内超低排放技术仅针对某些特定的燃料可达到超低排放，针对其他常规燃料，NOx和SO2能否达到超低排放仍需要进一步深入研究。

Circulating fluidized bed（CFB)boilers have become one of the best commercial technologies of clean coal combustion due to the advantage of inherent low cost of controlling pollutant emission. With the introduction of ultra-low emission standards,CFB combustion technology also faces huge challenges. In order to meet the ultra-low emission standards,the devices for treatment of flue gas are usually used,resulting in a significant increase in the cost of pollution treatment for CFB boiler. How to achieve ultra-low NOx and SO2 emissions of CFB boiler has become the research focus.The existing conventional ultra-low NOx emission technology of CFB,ultra-low SO2 emission technology of CFB,newly developed ultra-low NOx combustion technology of CFB,ultra-low SO2 emission technology in the furnace of CFB and ultra-low NOx and SO2 cooperative control technology of CFB were systematically discussed. The results show that high-efficiency separators cannot only improve the combustion efficiency of CFB,but also is the premise of using ultra-fine limestone for highly efficient desulfurization. The higher the separator efficiency is,the higher the CFB combustion efficiency and ultra-fine limestone desulfurization efficiency is. With the large-scale development of circulating fluidized bed boilers,the cross-section of the furnace is getting larger and larger,so how to achieve the horizontal uniform mixing of ultra-fine limestone in the large furnace becomes the first technical challenge. The technology for controlling a single gas to meet the ultra-low emission is relatively mature,but how to coordinately control NOx and SO2 to meet the ultra-low emission standard has become the second technical challenge. The current ultra-low emission technology in the furnace of CFB can only achieve ultra-low emissions for certain specific fuels,and however for other conventional fuels,whether NOx and SO2 can achieve ultra-low emissions still needs further deep research.

0 引言

1 CFB超低NOx排放技术

   1.1 常规CFB超低NOx排放技术

   1.2 CFB超低NOx燃烧技术

2 CFB超低SO2排放技术

   2.1 常规CFB超低SO2排放技术

   2.2 CFB超低SO2排放技术

3 CFB炉内超低NOx/SO2排放技术

4 CFB超低NOx/SO2排放技术

5 结语与展望