煤基固体燃料燃烧特性分析

Analysis on combustion characteristics of coal-based solid fuels

为揭示烧结固体燃料自身特性以及燃烧过程参数对燃烧行为及相关特征参数的影响规律,采用TG-DTG-DTA法针对燃料种类、准颗粒形态、粒径、氧体积浓度、升温速率等因素进行燃烧特性试验研究。结果表明,无烟煤的燃烧特性优于焦粉;P型准颗粒燃烧性能最优,S型最差,着火温度T_(g)从低到高依次为S<C≈P<S′,燃尽温度T_(b)为S<P<C<S′,质量失重峰值速率v_(max)则为S<S′<C<P,可燃性指数C为S<S′<C<P;随着粒径增大,T_(g)、T_(b)均向高温区移动,高温保持时间延长,而C呈现降低趋势;随着O_(2)体积分数提高,碳-氧界面燃烧反应程度加剧,T_(b)、峰值温度T_(max)向低温区迁移,v_(max)、C显著增大;受燃料自身热导率影响,升温速率提高,燃料颗粒内部的传热过程存在滞后现象,T_(b)、T_(max)开始整体向高温区迁移,v_(max)逐渐增高。

In order to reveal the influence of sintered solid fuel′s own characteristics and combustion process parameters on the combustion behavior and related characteristic parameters,the TG-DTG-DTA was used to perform single variable combustion test on fuel type,quasi-particle shape,particle size,oxygen volume concentration and heating rate.The results showed that the combustion performance of anthracite was better than that of coke,and for this performance,P-type quasi-particle was the best,S-type was the lowest.From lowest to highest,the sequence of ignition temperature(T_(g))was S<C≈P<S′,the burn-out temperature(T_(b))sequence was S<P<C<S′,the peak rate of mass loss(v_(max))sequence was S<S′<C<P,and the flammability index(C)sequence was S<S′<C<P.With the increase of particle size,T_(g) and T_(b) both moved to the high temperature zone,the high temperature retention time was prolonged,and C showed a decreasing trend.The degree of combustion reaction at the carbon-oxygen interface intensified with the increase of O_(2)volume fraction,T_(b) and peak temperature(T_(max))were migrated to low temperature zone,while v_(max) and C were significantly increased.Affected by the thermal conductivity of fuel itself,with the increase of heating rate,there was a hysteresis in the heat transfer process inside the fuel particles,T_(b) and T_(max)were migrated to the high temperature zone,and v_(max)was gradually increased.