烤烟秸秆炭化后理化特性分析

为有效开发利用烟草秸秆、实现烟田清洁生产,对烤烟秸秆在不同温度下炭化后的理化特性进行了研究。结果表明,烤烟秸秆炭化产率随温度升高而降低;低温炭化对全碳含量(质量分数)影响较小,但300℃以后,全碳含量随温度升高而下降;低温炭化时碳酸根和无机碳含量(质量分数)极低,从400℃开始明显增加;低温炭化时烟秆生物质炭p H呈弱酸性,300~800℃p H逐步上升,呈碱性;阳离子交换量(CEC)随炭化温度升高呈现出先增加后降低的趋势,400℃时达到最大;随炭化温度的升高,烤烟秸秆生物质炭表面碱性官能团增加、酸性官能团减少。烟秆生物质炭孔隙结构发达、多孔。烤烟秸秆的炭化温度以400~500℃为宜。 

Analysis of Physical and Chemical Properties of Carbonized Tobacco Stalks

For better utilization of tobacco stalks and clean tobacco production in fields, the physical and chemical properties of flue-cured tobacco stalks carbonized at different temperatures were studied. The results showed that the yield of tobacco stalk carbonization reduced with a rise in temperature. The total carbon content in carbonized stalk was slightly affected in low temperature carbonization, however it declined as the temperature rose to 300℃and above. Carbonate ions and inorganic carbon content was very low in low temperature carbonization, which increased obviously once temperature reached up to 400℃. In low temperature carbonization, the p H of tobacco-stalk-biochar presented weak acid, p H value rosesteadily and turned alkaline from 300 to 800℃. The cation exchange capacity(CEC) of tobacco-stalk-biochar increased first, then dropped with a rise in temperature, and peaked at 400℃. With a rise in carbonization temperature, the alkaline functional groups increased, while acidic functional groups reduced on the surface of tobacco-stalk-biochar. Tobacco-stalk-biochar was of porous structure. The appropriate carbonization temperature for flue-cured tobacco stalks is 400-500℃.