Electric Power ›› 2020, Vol. 53 ›› Issue (11): 234-242.DOI: 10.11930/j.issn.1004-9649.202002093

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SCR Zone-Based Hybrid Dynamic Leveling Technology and Its Application for W-Flame Boiler

XU Jian1, LUO Zhi2, ZHOU Xin3, LI Wenjie2, HUANG Shaobo3, CHANG Lei2, WANG Xiaobing2, NIU Guoping2, ZHANG Guangcai2   

  1. 1. China Resources Power Holdings Co., Ltd., Shenzhen 518001, China;
    2. Xi'an Thermal Power Research Institute Co., Ltd., Xi'an 710003, China;
    3. China Resources Electric (Lian Yuan) Co., Ltd., Loudi 417100, China
  • Received:2020-02-18 Revised:2020-04-18 Online:2020-11-05 Published:2020-11-05

Abstract: Burning anthracite in W-flame boiler inevitably results in the emission of high concentrations of NOx as much as 700~1 200 mg/m3 even with the low nitrogen combustion technology implemented. Therefore, the combination of “SNCR+SCR” is often adopted as the traditional route of ultra-low emission control. However, in addition to the high investment and operating costs, this technical route is extremely likely to cause excessive ammonia slip, which eventually leads to air preheater blockage. In this paper, the SCR transformation project of two 330 MW W-flame boilers are conducted by adopting the “SCR zone-based hybrid dynamic leveling technology”. The test results show that after the completion of the project, the SCR removal efficiencies of both boilers have been raised to more than the super high value of 94% while the ammonia escape rate is controlled under 2 μL/L. In this way, not only the goal of ultra-low emission can be achieved but also 14 million RMB of the SNCR investment and 7.6 million RMB of annual operation costs is saved respectively. Besides, to remove the same amount of NOx, 19% less ammonia is consumed after the transformation while the differential pressure of air preheater is still maintained stably in the long term.

Key words: W-flame boiler, SCR, partition mixing, dynamic leveling, ultra-low emission, ammonia escape