Electric Power ›› 2019, Vol. 52 ›› Issue (10): 155-161.DOI: 10.11930/j.issn.1004-9649.201808069

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SO3 Cooperative Control and Emission Situation in the Flue Gas of Coal-Fired Power Plant

LI Xiaolong1,2, LI Junzhuang1,2, DUAN Jiuxiang1,2, YI Yuping1,2, ZHANG Wenjie1,2   

  1. 1. Guodian Science and Technology Research Institute Co., Ltd., Nanjing 210046, China;
    2. Guodian Nanjing Electric Test Research Co., Ltd., Nanjing 210046, China
  • Received:2018-08-14 Revised:2018-12-28 Online:2019-10-05 Published:2019-10-12
  • Supported by:
    This work is supported by National Natural Science Foundation of China (No.41771498) and National Key R&D Program of China (No.2017YFB0603203).

Abstract: The conversion rate of SO2/SO3 is 0.5%~5% in boiler combustion, but it can be controlled within 1% in SCR DeNOx in coal-fired power plant. In operation, to control the consumption of SO3 in the sub-layer of SCR catalyst and air pre-heater in operation, the condensation adsorption quantity of H2SO4 and NH4HSO4 should be reduced as much as possible, which is aimed at protecting the catalyst activity and ensuring the safety of air pre-heater operation. Theoretically, the low-low temperature electrostatic precipitator has the excellent removal efficiency for SO3. However, the efficiency may changes from 1.8% to 96.6% in different projects. Study shows that the electrostatic-bag filter has removal efficiency about 74.3%~85.9% for SO3. Most technologies of wet flue gas desulfurization have removal efficiency of above 50% for SO3 except the empty absorption tower desulfurization and seawater desulfurization under ultra-low emission condition. Besides, the removal efficiency of wet electrostatic precipitator for SO3 can be above 50% as well, although there is still a slight gap compared with the mature cases abroad. Overall, the comprehensive removal efficiency for SO3 of the whole process environmental protection purification equipment of ultra-low emission coal-fired power plants is over 90% and the SO3 emission concentration of most units are less than 5 mg/m3, when the sulfur content of coal is under 1.5%.

Key words: coal-fired power plant, ultra-low emission, SO3, cooperation control, emission limit

CLC Number: