350MW超临界煤粉锅炉全燃准东煤的运行优化研究

Study on the operation optimization of 350 MW supercritical pulverized coal-fired boiler firing 100%Zhundong coal

为解决全燃准东煤受热面结渣、沾污等问题,在350 MW超临界煤粉锅炉上进行了准东煤掺烧高岭土混烧试验,累计运行397 d,各项参数指标均满足锅炉稳定运行要求。掺烧后进行了120 h热态调试,改善了锅炉掺烧后的运行状态,确定了锅炉310 MW最优工况下运行氧量应维持在2.8%~3.2%。研究指出在高负荷运行时优先使用5台磨煤机同时运行,且各磨煤机给煤量应该按照上层磨煤机小、下层磨煤机大的正宝塔形分布。提出在综合考虑NO;排放时,应尽量降低燃尽风层风箱开度,维持二次风上小下大的正宝塔形配风方式。通过掺烧高岭土和热态调试,实现了350 MW超临界锅炉全燃准东煤。

In order to alleviate the slagging and fouling on the heating surface of Zhundong coal in its pure combustion,the co-combustion of Zhundong coal and kaolin was tested in a 350 MW supercritical pulverized coal boiler for 397 days.All parameters of this test have met the requirements of stable operation of the boiler.A 120 h hot-state debugging can improve the operation state of the boiler taking co-combustion.The optimal oxygen content of the boiler under 310 MW working condition should be maintained between 2.8%~3.2%.The study points out that the five mills should be put into operation first during boiler high-load operation,and the distribution of the coal feed rates should be in pyramid shape,namely the coal feed rate of the upper-layer mill should be smaller and that of the lower-layer mill should be higher.Furthermore,comprehensively considering the NO_(x) emission concentration,the opening of OFA throttles should be kept as small as possible and the distribution of the secondary air should be in pyramid shape as well.The co-combustion test and hot-state debugging make the Zhundong coal pure combustion feasible on the 350 MW supercritical boiler.