【摘要】 为实现双流化床热解工艺所得低阶煤半焦的大规模利用,对半焦的悬浮燃烧特性进行了研究。以热重分析结果为依据,设计并搭建了适宜于研究半焦燃烧的沉降炉试验系统,对工艺半焦与低阶煤的燃烧效率与NO_x的生成规律开展了对比研究,并探讨了炉膛温度、氧气浓度、颗粒粒径对燃烧的影响。结果表明,和对应的煤相比,半焦具有更高的活化能,所需燃尽时间更长,在典型煤粉炉燃烧工况下基本燃尽,但是未完全燃烧热损失比煤高1.5%。半焦燃烧的NO_x排放浓度比煤低163 mg/m~3。研究还揭示了半焦和煤燃烧受炉膛温度、氧气浓度及颗粒粒径等因素的影响情况。研究结果可为在煤粉炉中大规模燃用半焦所需的相关结构改造及工况设置提供依据。更多还原

【Abstract】 To realize the large-scale and efficient utilization of the low-rank coal semi-coke obtained from the double fluidized bed pyrolysis process, the suspension combustion characteristics of the semi-coke were studied. The combustion and NO_x emission characteristics of the semi-coke and coal were studied in the drop tube furnace system which was designed and built based on the results of thermogravimetric analysis. The effects of combustion temperature, oxygen concentration and particle size on combustion were investigated. The results indicated that, compared with the corresponding coal, semi-coke had higher activation energy and required more time to burn out. Under typical pulverized-coal boiler combustion conditions, semi-coke could basically burn out, but its incomplete combustion heat loss was 1.5% higher than that of coal. The NO_x emission concentration was 163 mg/m~3 lower than that of coal. The influence of combustion temperature, oxygen concentration and particle size on the combustion of semi-coke and coal was revealed. The research results could provide reliable basis for the relevant structural transformation and working condition setting of large-scale combustion of semi coke in pulverized coal boiler.更多还原