燃煤锅炉偏转二次风炉内亚微米颗粒生成特性

Formation of particulated submicron matters in coal-fired boiler with deflected second air

为了研究炉内偏转二次风对燃煤过程中颗粒物生成的影响,通过建立与炉内三维气相流动控制方程一致的亚微米颗粒数量和质量控制方程,运用CFD软件模拟了NaOH颗粒在100 MW锅炉内的生成特性.结果显示:二次风偏转实现了炉内空气水平分级,降低了炉内峰值温度、缩小了高温区域,减少了矿物质气化量,进而在一定程度上抑制亚微米颗粒的生成.中间两层二次风偏转10°后,峰值温度比正常运行工况下的峰值温度约低30 K,NaOH颗粒质量浓度有一定下降.

The effect of the deflected second air on forming the particulate matter in coal combustion process was investigated. The particle formation of NaOH was simulated numerically by CFD software in a 100MW utility boiler, by creating the control equation of number and mass concentration of the submicron particulate matter, which were consisted with the gas flow equation. The results indicated that deflected second air can achieve air level of classifation in boiler, reduce peak temperature furnace and high-termperature region, shrink the amount of minerals gasification quantity, and then inhibit the generation of sub-micron particles to a certain extent. When the middle two-tier second air 10° deflection, the peak temperature is about 30 K lower than normal conditions, the NaOH particle concentration declined.