摘要
【目的】研究不同炭化时间对五节芒生物炭制备过程中理化特征及其微观结构表征的影响,探求其作为生物质能源的潜在应用价值。【方法】以五节芒为原材料,利用高温高压反应釜,在200℃下,水热炭化停留0、1.5、3.0、6.0、9.0 h制备生物炭,研究不同炭化时间对五节芒水热炭的有机碳、总氮、总磷、C/N、灰分、pH值、产率、元素损失率等的影响,并利用扫描电镜对其微观结构表征进行研究。【结果】在本试验条件下,五节芒生物炭有机碳含量为39.90%~54.82%,C/N为57.90~81.22,生物炭产率为57.3%~67.1%。五节芒生物炭中有机碳含量、总氮含量、C/N、碳损失率、磷损失率及灰分损失率随炭化时间的延长而增加,总磷含量、灰分含量、pH值及炭产率随炭化时间的延长而降低,氮损失率则在炭化达6 h时明显高于其他处理,9 h明显低于其他处理。扫描电镜观察结果显示五节芒生物炭富含淀粉颗粒,随炭化时间的延长,表面炭化现象比较明显,基本组织表面因增厚堆叠而开始变得杂乱,维管束大部分遭到破坏,薄壁细胞堵塞,薄壁细胞的边缘变厚但轮廓开始变得清晰,生物炭表面淀粉颗粒发生糊化,之后观察到了更多的形状不规则球体或椭球体的微球聚集融合,五节芒生物炭表面出现大量的微球结构。【结论】水热炭化改变了五节芒生物炭的理化特性和微观结构,且随炭化时间延长生物炭产率和pH值降低,碳、磷元素损失率增加;本试验条件下炭化3 h以上可显著改善生物炭的理化特性。
【Objective】The heating time in a hydrothermal carbonization process used to convert Miscanthus floridulus into biochar was varied to examine the chemical and microstructural differences in the resulting material for potential applications.【Method】An experiment applying 200℃ hydrothermal carbonization on the perennial grass in a pressurized reaction cauldron for 0,1.5,3.0,6.0,and 9.0 h was conducted.Properties including organic carbon,total nitrogen,total phosphorus,C/N ratio,ash,pH,yield,and loss of elements of the biochar were determined,and microstructure observed under a scanning electron microscope(SEM).【Results】After the carbonization,the biochar had an organic carbon content ranging from 39.90% to 54.82%,a C/N ratio from 57.90 to 81.22,and a yield from 57.3% to 67.1%.The longer the treatment time,the higher the organic carbon,total nitrogen,C/N ratio,carbon loss,phosphorus loss and ash loss were in the biochar.The total phosphorus,total ash,pH and yield decreased as well.The rate of nitrogen loss peaked after 6 h of carbonization but was significantly lower at 9 h compared with other treatment time.Under SEM,the biochar appeared with numerous starch particles.Prolonged carbonization significantly charred the surface with disorganized,thickened,and stacked tissues.Most of the vascular bundles was damaged,the thin-walled cells blocked,and the edges thickened with clear outlines.The starch granules began to slacken followed by the appearance of many irregular-shaped or ellipsoidal microspheres that coalesced and fused together.【Conclusion】The hydrothermal carbonization converted M.floridulus into biochar with changed chemistry and microstructure.Prolonged heating decreased the yield,pH,carbon,and phosphorus in the material.A carbonization time longer than 3 h could already significantly alter the properties of the biochar as observed under the experimental conditions.
作者
任丽花
叶菁
杨冬雪
翁伯琦
王义祥
REN Lihua;YE Jing;YANG Dongxue;WENG Boqi;WANG Yixiang(Institute of Agricultural Quality Standards and Testing Technology Research,Fujian Academy of Agricultural Sciences,Fuzhou,Fujian 350003,China;Agriculture Ecology Institute,Fujian Academy of Agricultural Sciences/Fujian Key Laboratory of Agricultural Ecological Process of Red Soil Mountain,Fuzhou,Fujian 350013,China;Fujian Provincial Environmental Monitoring Center,Fuzhou,Fujian 350003,China)
出处
《福建农业学报》
CAS
CSCD
北大核心
2020年第5期552-559,共8页
Fujian Journal of Agricultural Sciences
基金
国家重点研发计划项目(2016YFD0501404-3)
福建省财政专项——福建省农业科学院科技创新团队建设项目(STIT2017-3-9)
福建省红壤山地农业生态过程重点实验室开放课题(Aephrs-201803)。
关键词
五节芒
水热炭化
反应时间
生物炭
Miscanthus floridulus
hydrothermal carbonization
duration
biochar
