氮吸附法和压汞法测量生物质焦孔隙结构的比较

采用氮吸附法和压汞法对四种生物质焦（稻壳、树叶、玉米杆、棉花杆）的孔隙结构进行了测量，得到了两种测量方法下焦样的比表面积和孔径分布。结果表明不同测量方法得到的焦样比表面积和孔径分布有明显差别。氮吸附法主要测量焦样中微孔的孔隙结构，压汞法主要测量焦样大孔（和部分中孔）的孔隙结构。微孔对焦样的比表面积贡献最大，大孔对焦样的孔容积贡献最大。当热解温度升高时，焦样的微孔结构迅速增多，氮吸附法测得的比表面积变化大；而热解温度对大孔的影响较小，所以压汞法测得的比表面积变化不大。

STUDY ON POROSITY OF BIOMASS CHARS BY NITROGEN ADSORPTION METHOD AND MERCURY POROSIMETER

The porosities of four kinds of hiomass chars,rice shell,leaf, cornstalk,cotton stem were studied by using N2 adsorption method and mercury porosimeter. The specific surface area（SSA） and pore--size distribution obtacned by two methods differs greatly from each other. The micropore and mesopore of the biomass chars were studied By N2 adsorption method. The macropore and part of the mesopore were studied by mercury porosimeter. The results show that the micropore contributes to the SSA mostly,and the macropore contributes to the pore volume mostly. When the pyrolysis temperature increases,the number of the micropores increases greatly,and the SSA got by nitrogen adsorption method changes greatly. But the pyrolysis temperature has little effect on the macropores,so the SSA got by mercury porosimeter changes little.