摘要
用经典的静态重量法和色谱法,分别以CO_2和N_2为吸附质,研究了28种不同煤化度煤的表面积。结果发现,随煤化度增加,煤的N_2表面积与CO_2表面积的变化曲线均呈凹状,在C_(daf)=85%左右、V_(daf)=30%左右出现最小值;煤的N_2表面积的变化范围为1.63—13.30m.2·g^(-1),CO_2表面积的变化范围为25—332m^2·g^(-1);用DR方程、BET方程和Langmuir方程分别关联煤的CO_2吸附等温线计算出的煤表面积S_(DR)、S_(BET)和S_(Lang).有较大差异,但它们之间存在良好的线性关系: S_(DR)=-14.06+2.11S_(BET) S_(DR)=18.06+1.88S_(Lang)
The microstructure of twenty eight Chinese coals with rank from lignite to anthracite,has been studied by the adsorption of nitrogen at 77K and carbon dioxide at 298K,respectively.Their carbon contents(dry,ash free basis)range from 58.47 to 93.46%.The adsorption isotherms of carbon dioxide on coal have been used for calculating surface area with the DR,BET and Langmuir equations.The surface area of coal varies from 25 to 332m^2/g for carbon dioxide adsorption at 298K,whereas that for nitrogen adsorption at 77K varies from 1.63 to 13.30m^2/g.The surface area obtained from carbon dioxide adsorption at 298K is consistently higher than that obtained from nitrogen adsorption at 77K,indicating the molecular sieve characteri stic of coal.The variation curve of surface area versus coal rank shows a minimum at carbon content of ca.85%(d.a.f)and at volatile matter content of ca.30%(d.a.f).The surface area of coal by carbon dioxide adsorption——S_(DR),S_(BET)or S_(Lang).,which are obtained with DR,BET and Langmuir equations respectively differs from each other,but good linear relationship exists among them:S_(DR)=-14.06+2.11 S_(BET)S_(DR)=18.06+1.88 S(Lang).
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
1991年第3期253-260,共8页
Journal of Fuel Chemistry and Technology
基金
国家自然科学基金
关键词
煤
表面积
微孔结构
coal
microstructure
adsorption equation
surface area
