压汞法分析生物质焦孔隙结构

对于稻壳、树叶、棉花杆、玉米杆四种生物质焦,通过压汞法测量了其在大孔和部分中孔范围内的孔隙结构,发现热解温度、热解保持时间、热解快／慢速都会影响着焦样的比表面积和平均孔径。四种生物质中,树叶焦样的比表面积最大,玉米杆的比表面积最小;稻壳焦样的平均孔径最小,玉米杆的平均孔径最大。不同生物质焦样的孔径分布规律有很大不同。热解温度、热解速度和热解保持时间对孔径分布规律的影响不大,决定孔径分布规律的是生物质本身。在中孔和大孔的范围内,四种生物质焦样的孔径分布曲线都呈现出双峰结构。

DETERMINATION OF POROCITY OF BIOMASS CHARS USING MERCURY POROSIMETRY

The porocity of four kinds of biomass chars, rice shell, leaf, cornstalk and cotton stem, was studied using mercury porosimetry. The results show that pyrolysis temperature, pyrolysis time and pyrolysis rate have an obvious effect on the special surface area(SSA) and average pore size(APS) of the biomass chars. Among the four kinds of biomass, the leaf char has the biggest SSA while the cornstalk char has the least. The rice shell char has the least APS while the cornstalk has the biggest. There are obvious difference in the pore-size distribution of the biomass chars studied. The pyrolysis temperature, pyrolysis time and pyrolysis rate have little effect on the pore-size distribution which is determined by the kind of the biomass. In the range of the mesopore and macropore, there are two apexes on the pore-size distribution curves.