保温时间对不同秸秆生物炭肥料化利用理化特性的影响

Effects of holding time on physical and chemical properties of utilizing different straw biochar fertilizer

试验以水稻、小麦、玉米、油菜和棉花秸秆为研究对象,考察不同保温时间对5种秸秆生物炭的炭产率、组成成分、pH、电导率和孔隙结构的影响,并对不同生物炭理化特性的相关性进行分析。结果表明,保温时间和原料种类对秸秆生物炭肥料化利用的理化特性均有显著性影响(P<0.05)。秸秆生物炭产率为41%~61%、碳转化率为53%~65%。保温时间从0 min增加到120 min,炭产率减少而生物炭的固定碳含量增加,pH和电导率增加,孔壁变薄孔径增大。保温时间与秸秆生物炭的炭产率、H、O和挥发分含量呈显著的线性负相关,与固定碳含量呈显著线性正相关。保温时间为60~90 min时,秸秆生物炭的H/C<1,芳香化程度较高,性质稳定。生物炭表面光滑,内部具有较大的空腔,且生物炭的pH、电导率较高,挥发分含量低,是一种较好的炭基肥添加剂材料。

The effects of different holding times on the biochar yield,composition,pH,electrical conductivity and pore structure of five kinds of straws including rice,wheat,corn,rape and cotton were investigated.Correlation between the physical and chemical properties of different biochars was analyzed.The results showed that effects of straw type and holding time on the physicochemical properties of biochar fertilizer were significant(P<0.05).The biochar yields and the carbon conversion efficiency of straws ranged from 41%to 61%,and 53%to 65%,respectively.With the increase of holding time,the biochar yields decreased,while the pyrolysis degree and the fixed carbon contents of biochars increased.The pH and electrical conductivity increased with the increase of holding time.The holding time was negatively correlated with carbon yield,H,O contents and volatile matter content of biochars,and positively correlated with fixed carbon content.The optimal holding time is 60-90 min,and the biochars obtained under this condition has a rich pore structure with smooth surface.The biochars with lower H/C and higher pH and electrical conductivity can be used as a good carbon-based fertilizer additive material.