水热预处理对樟木屑制备成型燃料行为的影响

摘要

针对成型燃料制备过程中存在的产品质量不佳问题,在200～260 ℃对樟木(Cinnamomum camphora(L.)Presl)屑进行水热预处理,并制备成型燃料,考察水热预处理条件对成型能耗和成型燃料品质的影响.结果表明:水热预处理提高了小粒径微粒的含量和成型燃料的梅耶(Meyer)强度,降低了樟木屑的塑性但提高了成型中的挤压能耗和推动能耗.水热预处理显著促进樟木屑中半纤维素的降解,降低了吸水性和挥发分含量,并提高了成型燃料的着火温度和燃烬温度,降低了最大燃烧速率,将综合燃烧特性指数由6.96 mg2/(min2·℃3)降低至1.89～3.44 mg2/(min2·℃3),使成型燃料具有燃烧稳定和使用安全的优点.%In the present work,the effect of hydrothermal preatment on pelletization energy consumption and pellets' properties was carried out.The woody sawdust(Cinnamomum camphora(L.)Presl)was pretreated by hydrothermal pretreatment in the temperature range of 200-260℃,and then compressed into woody pellets,in order to solve the current problem of low quality of pellet properties in woody pellet industry.It was shown that the content of fines and the pellets' Meyer hardness were increased after the hydrothermal preatment.However,the plasticity of sawdust was reduced during hydrothermal pretreatment,resulting in the increase of compaction and extrusion energy consumption during pelletization.The decomposition of hemicellulose was improved during hydrothermal pretreatment,decreasing the moisture absorption and volatile content of pellets.The ignition temperature and burnout temperature of pellets were enhanced after hydrothermal preatment,which decreased the maximum buring rate,resulting in the increment of Composite combustion characteristic index from 6.96 mg2/(min2·℃3)to 1.89-3.44 mg2/(min2·℃3).Therefore,the hydrothermal preatment of Cinnamomum camphora(L.)Presl could improve the burning stablity and safty of pellets.