玻璃熔窑烟气再循环联合燃尽风燃烧数值模拟

Numerical simulation of flue gas recirculation combined over-fired air combustion in glass melting furnace

玻璃熔窑在采用高温低氧燃烧(HTAC)技术的条件下使用烟气再循环联合燃尽风燃烧对降低NO_(x)排放有极其显著的效果。基于数值计算方法建立了烟气再循环联合燃尽风燃烧数学模型,并通过实际运行数据与仿真结果对比验证了该模型的可靠性。研究表明:(1)随着烟气循环率增长,炉膛火焰温度下降,小炉出口NO_(x)浓度下降;(2)加入燃尽风有利于提升烟气对玻璃液的热通量;(3)本研究条件下烟气再循环联合燃尽风降氮燃烧优化运行参数为:烟气循环率5%,燃尽风率20%;在优化参数下运行时,其对应的NO_(x)质量流量为0.00951 kg·s^(-1),热通量为41.54 kW·s^(-1),与基础工况(循环率0、燃尽风率0)相比,NO_(x)排放浓度下降60.73%,烟气与玻璃液间热通量增加13%;而与循环率0、燃尽风率20%的工况相比,NO_(x)浓度下降49.4%,烟气与玻璃液间热通量下降3.7%。为玻璃熔窑NO_(x)减排提供了理论支持。

The use of flue gas recirculation combined with over-fired air combustion under the conditions of high temperature and low oxygen combustion(HTAC)technology in the glass melting furnace has an extremely significant effect on reducing NO_(x)emissions.In this paper,a mathematical model of flue gas recirculation combined with over-fired air combustion is established based on numerical calculation methods,and the reliability of the model is verified by comparing actual operating data with simulation results.Research results show:(1)As the flue gas circulation rate increases,the temperature of furnace flame decreases,and the NO_(x)concentration at the outlet of the small furnace decreases;(2)The addition of burn-out air is beneficial to increase the heat flux of the flue gas to the molten glass;(3)The optimized operating parameters of flue gas recirculation combined with over-fire air nitrogen reduction combustion under the research conditions of this paper are:flue gas circulation rate 5%,over-fire air rate 20%.Compared with the basic operating conditions(circulation rate 0,over-fire air rate 0),when running under optimized parameters,the corresponding NO_(x)mass flow is 0.00951 kg·s^(-1),and the heat flux is 41.54 kW·s^(-1).Compared with the basic operating conditions(circulation rate 0,over-fire air rate 0),the NO_(x)emission concentration is reduced by 60.73%,and the heat flux between flue gas and glass liquid is increased by 13%.Compared with the working condition of circulation rate 0 and over-combustion air rate 20%,the NO_(x)concentration drops by 49.4%,and the heat flux between flue gas and molten glass drops by 3.7%.The results of this study provide theoretical support for NO_(x)reduction in glass melting furnaces.