关键词:

O₂/CO₂气氛, 煤粉燃烧, N₂吸附, 孔隙结构, 扫描电镜

Abstract:

In a drop tube furnace with the similar combustion conditions of actual furnace, coal char samples with various burn-off rates, were prepared in different environments and analyzed with N₂ adsorption analyzer at a low temperature and scanning electronic microscope (SEM).The results showed that both burning rates and burn-off rates of chars in O₂/CO₂ environment were lower than those in O₂/N₂ environment with equivalent O₂ concentration and same operating conditions.The CO₂ char (derived in O₂/CO₂ environment) showed lower specific surface area and specific pore volume than that of the N₂ char (derived in O₂/N₂ environment).During the combustion processes, pore structure parameters of all samples, such as S_BET and V_BJH decreased with the increase in burn-off rate.The results also indicated that the CO₂ char showed poor pore distribution among a region less than 5 nm but correlated with coal rank.SEM results also indicated the same regularity and agreed well with those determined by the N₂ adsorption method.

Key words:

O₂/CO₂气氛, 煤粉燃烧, N₂吸附, 孔隙结构, 扫描电镜