球磨预处理对稻草热解行为的影响研究  

Effect of Ball Milling on the Pyrolysis Behavior of Rice Straw

作　　者：杨圩 YANG Wei(School of Environmental Science and Engineering,Tianjin University,Tianjin 300073,China;College of Engineering,Huzhou University,Huzhou 313000,China;Zhejiang ECO Environmental Technology Co.,Ltd.,Huzhou 313000,China)

机构地区：[1]天津大学环境科学与工程学院,天津300073 [2]湖州师范学院工学院,浙江湖州313000 [3]浙江宜可欧环保科技有限公司,浙江湖州313000

出　　处：《山东化工》2024年第24期5-7,12,共4页Shandong Chemical Industry

基　　金：湖州市科技特派员项目(2023KT83)。

摘　　要：纤维素、半纤维素和木质素缠结结构以及纤维素的晶型结构导致生物质很难在较低的温度下被热解。如何通过预处理高效破坏生物质的结构是实现其低温热解的关键。以稻草作为生物质代表,利用球磨预处理稻草,并对其物理化学性质与热解动力学进行了研究。结果表明球磨预处理可以有效地破坏稻草结构。球磨处理后稻草的水溶性从6.25%上升到12.8%,提高了近一倍;球磨处理后稻草晶型结构也被破坏,结晶指数从原来的36.5%降低到30.7%。晶型结构的破坏使得球磨后稻草的热稳定明显降低,在相同温度下球磨后稻草的失重率低于未球磨处理稻草。由于球磨过程中木质素的结构遭到破坏,导致球磨处理的稻草最终热解产物收率也远远低于未球磨处理稻草。球磨前后稻草的热解可以分成三个阶段,它们在阶段2和阶段3的热解动力学可分别由Coats-Redferm法中的third-order模型和two-way transport模型进行拟合。球磨前后稻草在阶段2和阶段3的活化能分别为22.8和53 kJ/mol、51和3.8 kJ/mol,指前因子分别为39.5和80121 s^(-1)、1059.5和0.013 s^(-1)。The existence of crystallinity of cellulose and entanglement of the cellulose,hemicellulose and lignin fractions made biomass difficult to be pyrolyzed at a relative lower temperature.Efficient destruction of the rigid structure in biomass through pretreatment is the key for efficient conversion of biomass in low pyrolysis temperature.In this study,ball milling was employed to pretreat rice straw that was employed as a model of biomass to destroy its rigid structure.The effect of ball milling on the properties and pyrolysis kinetics of rice straw were further investigated.It was found that ball milling could efficiently destroy the rigid structure of rice straw.The solubility of rice straw increased from 6.25%to 12.8%,two folds higher than that of raw rice straw.Meanwhile,the crystalline index reduced from 36.5%to 30.7%,resulting in the lower biochar yield at the end of pyrolysis process.The pyrolysis periods of rice straw before and after ball milling could be divided into three stages.The pyrolysis kinetics of rice straw before and after ball milling could be well expressed by third-order and two-way transport kinetic models in Coats-Redferm method,respectively.The activation energies in stage 2 and stage 3 for rice straw and ball-milled rice straw were determined to be 22.8 and 53 kJ/mol,and 51 and 3.8 kJ/mol,respectively.The pre-exponential factors were calculated to be 9.5 and 80121 s^(-1),1059.5 and 0.013 s^(-1),respectively.

关 键 词：稻草 球磨 热解动力学 Coats-Redferm法 

分 类 号：O636.2[理学—高分子化学] O658[理学—化学]