富氧气氛下生物质/煤恒温混燃特性及同步NO释放规律的研究

Study on Co-combustion Characteristics and NO Release Laws of Biomass and Coal Blends at Constant Temperatures in Oxygen-enriched Atmosphere

利用恒温热重及NO监测装置,进行了富氧气氛下生物质/煤恒温混燃实验,研究了不同气氛、掺混比、煤种、温度及生物质种类下生物质/煤富氧燃烧特性及NO释放规律,为生物质/煤富氧燃烧的实际应用提供一定的参考。结果表明:气氛变化对挥发分析出燃烧段的影响很小。在21%O2浓度下,富氧气氛相比空气气氛,样品燃烬时刻略有延迟,NO释放量减小。随着O2浓度升高,样品的平均失重率增大,NO释放量增大。掺混玉米芯后,样品燃烬时刻明显提前,且随着玉米芯掺混比的增加,玉米芯对煤粉燃烧促进作用增强,NO释放量呈下降趋势。随着煤阶降低,玉米芯对煤的促燃作用减小,3种煤在掺混玉米芯后,NO释放量均有不同程度的降低。随温度升高,样品燃烬时刻缩短,NO释放量增大。掺烧3种生物质后,样品燃烬时刻均明显提前,NO释放量均有下降。

To provide a reference for the practical application of biomass/coal in oxygen-enriched combustion, the co- combustion characteristics and NO release laws of biomass and coal blends under different atmosphere,blending rati- o,temperature, coal and biomass were studied by the isothermal thermogravimetric and NO emission monitoring sys- tem. The results show that it has little effects on the stage of devolatilization when changing atmosphere. Compared to air atmosphere,the sample in the oxygen-enriched atmosphere leads to a slighter burnout time delay and less NO cu- mulative emissions at 21% oxygen concentration. As environmental oxygen concentration increases, the average weight loss rate of coal enhances and NO cumulative emissions increases. With blending corncob, the samples＇ burn- out time is significantly reduced. Along with the blending corncob ratio increasing,the combustion promoting effect enhances and NO cumulative emissions show a decreasing tendency. While the combustion promoting effect weakens with the coal rank decreasing, the NO cumulative emissions of three kinds of coal blending corncob decrease in differ- ent degree. With the increase of temperature, the burnout time of sample reduces and the NO cumulative emissions increases. With blending three kinds of biomass,the samples＇ burnout time is significantly reduced and all the NO cumulative emissions reduces.