恒温下煤与生物质混燃过程中NO2释放特性

NO2 EMISSION CHARACTERISTICS OF PULVERIZED COAL AND BIOMASS CO-COMBUSTION AT CONSTANT TEMPERATURE

利用恒温燃烧污染物在线监测系统,研究生物质掺混比、生物质种类、温度、反应气氛等因素对煤混燃生物质时NO2释放规律的影响。结果表明:增大秸秆掺混比例,使NO2瞬时释放峰值、释放总量增大,转化率提高。改变混燃生物质种类时,随着生物质中Fe2O3、CaO等矿物质含量的减小,NO2释放总量、转化率增大。升高温度能加快NO2生成速率,同时提高NO2还原速率,但在800℃以上的高温下,后者增加程度高于前者,造成NO2释放总量及转化率先增大后减小。O2/N2气氛下,提高O2浓度能增大NO2转化率与释放总量,而O2/CO2气氛下由于焦炭气化反应及还原作用的影响,提高O2浓度会造成相反的趋势。

The effects of biomass blending ratio,biomass species,temperature and atmosphere on the emission characteristics of NO2 from biomass mixed with coal were investigated by using the on-line measurement system of combustion pollutants.The results showed that with the enhancement of straw blending ratio,the instantaneous release peak of NO2 rise,the total amount of NO2 released and the NO2 conversion rate increase.Both the total amount of NO2 released and the NO2 conversion rate increase with the content of Fe2O3,CaO and other minerals reduced in blending biomass.When the temperature is raised,the formation and release process of NO2 have been accelerated as well as increasing the NO2 reduction rate.The reduction increases more at high temperature above 800℃,resulting in a decrease of NO2 release and the conversion rate.Under the O2/N2 atmosphere,the increasing O2 concentration could improve the NO2 conversion rate and stimulate the NO2 release,which have an opposite trend due to the influence of gasification and reduction of char under the O2/CO2 atmosphere.