CIESC Journal ›› 2017, Vol. 68 ›› Issue (3): 1178-1184.doi: 10.11949/j.issn.0438-1157.20161189

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Effects of Na/K additives on NO reduction and its promotion mechanism in SNCR process

SUN Tong1, LU Ping1, CAI Jie1, WU Jiang2   

  1. 1 School of Energy & Mechanical Engineering, Nanjing Normal University, Nanjing 210042, Jiangsu, China;
    2 College of Energy & Mechanical Engineering, Shanghai University of Electric Power, Shanghai 200090, China
  • Received:2016-08-25 Revised:2016-11-08 Online:2017-03-05 Published:2016-12-05
  • Contact: 10.11949/j.issn.0438-1157.20161189 E-mail:luping@njnu.edu.cn
  • Supported by:

    supported by the National Natural Science Foundation of China (51476079),Jiangsu Province Prospective Cooperation Research Project of China (BY2015001-01) and Jiangsu Province Major Project of University Natural Science Research of China (15KJA610002).

Abstract:

The effects of Na/K additives (NaOH, Na2CO3, NaCl, KOH, K2CO3 and KCl) on NO reduction in the selective non-catalytic reduction (SNCR) process were simulated by using Chemkin software based on the established chemical mechanisms of Na-K-C-H-O-N-Cl. The mechanism and routes of Na/K additives on NO reduction in the SNCR process were discussed based on the sensitivity analysis and rate of production (ROP) analysis. The simulated results indicated that NO removal efficiency was almost zero at temperature of 700-800℃ in the SNCR process without Na/K additives. Na/K additives had a significant promotion on NO reduction at temperature lower than 800℃, and had less promotion on NO reduction at temperature higher than 900℃. At temperature of 700℃, NO removal efficiency was 43.86%-60.76% in the SNCR process with Na/K additives. The promotion order of Na/K additives on NO reduction in the SNCR process was NaOH≈Na2CO3 > KOH≈K2CO3 > KCl > NaCl. However, the concentration of Na/K additives (6.25-25.0 μmol·mol-1) showed little influence on NO reduction. NO reduction in the SNCR process was performed through NH2 radicals, which were promoted by OH radicals via respective reaction routes promoted by Na/K additives. The promotion of Na/K additives on NO reduction in the SNCR process was enhanced by alkali metal hydroxides (MOH) via the route of NaOH→NaO2→Na→NaO→NaOH, but weakened by alkali metal chlorides (MCl) via the route of MCl→M→MCl.

Key words: SNCR, NO reduction, Na/K additives, dynamics simulation

CLC Number: 

  • TK229.6

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