炉膛漏风对煤粉炉O_2/CO_2气氛燃烧影响的模拟研究

Numerical Simulation Study on the Influence of Air Leakage of Furnace upon Oxy-Fuel Combustion in Pulverized Coal Boiler

采用一种全新的网格画法,运用FLUENT软件对1台300 MW四角切圆煤粉锅炉在不同工况下的炉内流动、传热、燃烧及污染物排放规律分"无漏风"和"有漏风"2种情况进行了数值模拟.结果表明:炉膛漏风使排烟温度升高、烟气中CO_2浓度降低、NO浓度升高,导致排烟损失、CO_2捕集回收难度及污染物排放量增加;随着O_2浓度的升高,漏风的影响加剧,锅炉运行的经济性大幅降低,甚至存在安全隐患.

A new grid method was adopted. The simulation has been divided into two cases： non air leakage and existing air leakage. In both cases, numerical simulation of flow, heat transfer, combustion and pollution release law in a 300 MW tangentially coal fired boiler under different conditions are performed by FLUENT software. The results showed that with air leakage of furnace, flue gas temperature rises, CO2 concentration de- creases and NO concentration increase, which leads to the increase of flue gas loss, the difficulty of CO2 recovery and emission amount of pollutions.With the increase of O2 concentration, the impact of air leakage grew in fur- nace, the economy of boiler operation reduced significantly, and even the security risks also increased.