链条炉SNCR脱除NO_x数值模拟研究  

SIMULATION STUDY ON SNCR FOR NOx REMOVAL FROM CHAIN-GRATE FURNACE

作　　者：胥波[1] 张彦文[1] 蔡宁生[1] 

机构地区：[1]清华大学热科学与动力工程教育部重点实验室,北京100084

出　　处：《热力发电》2009年第3期18-25,共8页Thermal Power Generation

基　　金：国家高技术研究发展计划(863计划)资助项目(2006AA06A304)

摘　　要：建立1台35 t/h链条炉煤层燃烧过程的数学模型,将模拟得到的气体温度分布及其组分浓度分布作为炉膛空间数值模拟的边界条件,采用计算流体力学软件FLUENT对链条炉内的温度和流场分布进行模拟,并以此为基础对该锅炉的选择性非催化还原(SNCR)脱除NOx过程进行初步设计。模拟结果与实测数据的对比表明,所建的煤燃烧模型可较准确地模拟和预测典型链条炉的燃烧过程。由模拟结果可知,常规链条炉SNCR脱除NOx过程中,适宜温度区狭窄,烟气停留时间较短,因此NOx脱除率较低。在相同工况下,加入适量甲烷可使氮氧化物脱除效率提高9%左右,氨泄漏降低至50μL/L。A mathematical model for combustion process in chain- grate furnace of a 35 t/h boiler has been established, taking the gas temperature distribustion and concentration of flue gas comstituents as the boundary conditions for simulation space in the furnace, the temperature and flow field distribution have been simulated by using a computational fluid dynamics software FLUENT and the Selective Non - catalytic Reduction （SNCR） process of the NOx removal in a chain -grate furnace being designed primarily. The comparison of simulated results with actually measured data shows that the typical combustion process on a chain- grate can be simulated and predicted by using the established combustion model. In conventional SNCR process of NOx removal, the space of suitable temperature regions is narrow, the residence time of flue gas in the furnace being shorter, hence, the removal efficiency being lower,hut the NOx removal efficiency can be enhanced in a similar operation by suitably adding methane,the NOx removal efficiency can be enheanced by about 9%, and the ammonia leakage can be lowered to 50 μL/L.

关 键 词：链条炉 烟气 NOx控制 SNCR 数值模拟 

分 类 号：TK224.1[动力工程及工程热物理—动力机械及工程]