垃圾焚烧炉烟气再循环改造的数值模拟与试验研究

Numerical Simulation and Experimental Investigation on Retrofit of Flue Gas Recirculation in Waste Incinerator

对山东某500t/d垃圾焚烧炉排炉烟气再循环技术改造项目进行了研究,重点关注了烟气再循环对脱硝效果、燃尽率和运行经济性的影响.对六种焚烧炉运行工况进行了现场试验和数值模拟,数值模拟结果在火焰形态、温度分布、NOx变化趋势等方面与运行结果吻合良好.研究结果表明烟气再循环率对垃圾焚烧炉内NOx生成影响较大;NOx同时受炉内温度与O2含量的影响,过量空气系数越小NOx排放越低;相比改造前,烟气再循环可以实现在不提高运行费用的条件下联合SNCR将NOx排放控制在100mg/m3以下.经济性分析结果表明,烟气再循环技术相比其他脱硝技术具有较为明显的环保效益和经济效益,并且几乎不影响料层燃尽.

A technological retrofit project of flue gas recirculation(FGR)was implemented on a 500 t/d waste incinerator in Shandong Province,and the influences of FGR on the denitrification effect,burn-out rate and economic efficiency of operation were focused.Field tests and numerical simulations were conducted under six types of operating conditions.Simulation results agree well with the operation data in aspects of flame shape,temperature distribution,the varying trend of NOx emission,etc.Research results show that FGR has an obvious influence on NOx production in the waste incinerator.Both temperature and oxygen content inside the incinerator have impacts on the NOx emission.The smaller the excess air coefficient in the incinerator,the lower the production of NOx.Combined with SNCR,FGR can reduce the NOx value to lower than 100 mg/m3 without increasing the operation cost.The result of economic analysis indicates that compared with other denitrification technologies,FGR has obvious environmental and economic benefits,and it almost has no effect on the bed burning out.