O_2/CO_2气氛煤焦的燃烧及其孔隙结构变化  

Combustion of pulverized coal in O_2/CO_2 mixtures and its pore structure development

作　　者：李庆钊[1] 赵长遂[1] 陈晓平[1] 武卫芳[1] 李英杰[1] 

机构地区：[1]东南大学能源与环境学院,江苏南京210096

出　　处：《化工学报》2008年第11期2891-2897,共7页CIESC Journal

基　　金：国家重点基础研究发展计划项目(2006CB705806);江苏省普通高校研究生科研创新计划项目(CX07B091Z);东南大学优秀博士学位论文基金项目~~

摘　　要：采用热力工况与实际煤粉炉相近的沉降炉实验装置,制备了不同环境气氛下(O2/N2及O2/CO2气氛)、不同燃尽率的煤焦试样,并采用低温氮吸附仪和扫描电子显微镜测定了其孔隙结构和表面形貌。结果表明,在相同的操作条件下,相同O2浓度的O2/CO2气氛下煤焦的燃烧速率较慢、燃尽率较低,各试样的孔比表面积和比孔容积均较小。两种气氛下燃尽过程孔结构参数(SBET和VBJH)均呈减小趋势,且在孔径变化较明显的区域内(<5 nm)在CO2气氛下煤焦的孔径分布较小且与煤种相关。SEM图像显示CO2气氛下的煤焦表面致密,孔隙较少,其定性结果与N2吸附法的定量测量结果吻合较好。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 SBET and VBJH 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.

关 键 词：O2/CO2气氛 煤粉燃烧 N2吸附 孔隙结构 扫描电镜 

分 类 号：TQ534.9[化学工程—煤化学工程]