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—25.0μmol·mol?1) showed little influence on NO reduction. NO reduction in the SNCR process was performed through NH2 radicals, which were promoted by OH radicalsvia 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.%基于构建的Na-K-C-H-O-N-Cl化学反应机理模型,采用Chemkin动力学模拟软件,研究Na/K添加剂(NaOH、Na2CO3、NaCl、KOH、K2CO3和KCl)对选择性非催化还原(SNCR)脱硝性能影响,通过敏感性分析和产率分析,探讨Na/K添加剂对SNCR过程中NO还原的促进机理和路径.模拟结果表明,在温度为700~800℃且无Na/K添加剂条件下,SNCR脱硝效率几乎为零;Na/K添加剂能够显著提高低温区(小于800℃)SNCR脱硝效率,而其对高温区(大于900℃)SNCR脱硝的促进作用不明显.在温度为700℃和Na/K添加剂参与条件下SNCR脱硝效率可达43.86%~60.76%.不同Na/K添加剂对NO还原促进顺序为NaOH≈Na2CO3>KOH≈K2CO3>KCl>NaCl,但同一种Na/K添加剂的浓度变化(6.25~25.0μmol·mol?1)对SNCR脱硝效率影响较小.Na/K添加剂通过不同的循环路径产生OH基,进而通过NH2基团促进NO的还原,其中碱金属氢氧化物(MOH)对SNCR脱硝的促进路径为NaOH→NaO2→Na→NaO→NaOH,碱金属氯化物(MCl)则主要通过MCl→M→MCl削弱Na/K添加剂的促进作用.
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