900t/d生活垃圾焚烧炉二次风优化数值模拟

Numerical Simulation of Secondary Air Optimization in a 900t/d Waste Incinerator

针对某台900 t/d高热值垃圾焚烧炉焚烧城市生活垃圾的过程进行数值模拟,利用FLIC和Fluent耦合的方法,研究了前后拱二次风喷入角度和前后拱二次风与烟道二次风配比对炉内垃圾燃烧过程、流场分布、烟气主要组分分布及污染物排放特性规律等影响。结果表明:在相同工况下,垃圾焚烧炉炉内烟气流场、组分浓度和污染物排放量与现场数据相符。前后拱二次风喷入角度分别为67°和47°时,炉内温度分布均匀,对壁面高温腐蚀减弱,第一烟道烟气出口温度达到907℃,炉膛火焰呈中心对称分布,炉内烟气与二次风混合良好,NOx排放为132.5 mg/m^3;燃尽风、前拱、后拱二次风配比为0.38∶0.46∶0.16,炉膛二次风扰动较大,炉膛烟气与氧气混合度高,气相燃烧旺盛,烟气在炉内停留时间延长,可燃组分燃烧充分,温度场集中在炉膛中部,NOx排放减少。

The numerical simulation of the burning process of municipal solid waste with high calorific value in a 900 t/d incinerator was carried out.The FLIC and Fluent coupling method was used to study the secondary wind injection angle of the front and rear arches,the secondary wind of the front and rear arches and the secondary wind of the flue.The ratio of the internal combustion flow in the furnace,such as the combustion process of the waste in the furnace,the distribution of the flow field,the distribution of the main components of the flue gas,and the characteristics of the pollutant discharge were studied.The results show that the flue gas flow field,component concentration and pollutant emission in the incinerator are consistent with the field data under the same conditions.When the secondary wind injection angles of the front and rear arches are 67°and 47°,the temperature distribution in the furnace is uniform,and the high temperature corrosion on the wall is alleviated.The temperature of the first flue gas outlet reaches 907℃,and the furnace flame is symmetrically distributed at the center.The flue gas in the furnace is well mixed with the secondary air,and the NOx emission is 132.5 mg/m^3.When the ratio of the secondary wind of the burnout wind,the front arch and the rear arch is 0.38∶0.46∶0.16,the disturbance of secondary wind in the furnace is strong,the furnace flue gas and oxygen is fully mixed,and gas phase combustion is strong.The residence time of flue gas in the furnace is prolonged,thus combustible components are fully burned.The temperature field is concentrated in the middle of the furnace,and NOx emissions are reduced.