CFB调峰锅炉NO_x排放特性试验研究

Experimental study on NO_x emissions characteristics of CFB peak shaving boiler

目前燃煤锅炉深度调峰运行造成效率降低及污染物排放难以控制是普遍存在的问题,通常对锅炉进行燃烧优化试验,以解决调峰运行时负荷降低的稳燃问题,达到控制污染物排放目的。通过对唐山某电厂150MW CFB机组进行试验,分析在变工况运行时NO_x释放与相关影响因素的关系特性。结果表明:随机组负荷增加、水煤比降低、氨氮比提高,有利于控制NO_x的排放;烟气氧含量控制在5%以下,并且保持脱硝过程在最佳的SNCR反应温度区间,可有效提高脱硝效率,但不能单独改变炉膛的一、二次风比,还要综合床温、过量空气系数等其他因素。文中研究结果可为CFB电站深度调峰提供参考。

It is a common problem that current coal-fired boilers regularly run in deeply peak load lead to the lowefficiency and pollutant discharge is difficult to control. In a normal way,the boiler combustion optimization experiment was carried out,in order to solve the problem of low-load stable-combustion when peak load regulating operation,and achieve the goal of pollutant discharge controlling. Taking a 150 MW CFB boiler in Tangshan as example,it studied the relationship between NO_x emissions of boiler variable condition operation and related influence factors. The results showed that the increase of the load,decrease of the ratio of water and coal,and increase of the ratio of ammonia and nitrogen were beneficial to control NO_x emission; Controlling flue gas oxygen content under 5% and keeping the NO_x denitration process at the best SNCR reaction temperature range,can effectively improve the NO_x denitration efficiency; However,it can not only change proportion of primary and secondary air,but also to take other factors such as bed temperature and excess air coefficient into consideration. The results of the study can provide reference for CFB plants peak shaving operation.