厨余垃圾厌氧沼渣热解特性及动力学分析

Characterization and Kinetic Analysis of Pyrolysis of Anaerobic Digestate from Kitchen Waste

围绕厨余厌氧发酵技术中厌氧沼渣处理难的问题,以高纯N2为载气,气体流量为50 mL/min,选择升温速率5、10、15、20、30℃/min,热解终温为850℃,开展了厨余厌氧沼渣热解动力学研究。以3种不同热分析方法Flynn-Wall-Ozawa(FWO)、Kissinger-Akahira-Sunose(KAS)和Coats-Redfern(CR)综合比较,研究了球磨时间和升温速率对沼渣热解活化能分布的影响规律,并结合CR法对由Popescu法筛选取得的最佳机理函数进行拟合。结果表明:厨余沼渣的热解过程主要分3个阶段进行;CR法计算的活化能数值较为接近实际值,约为41.32~46.49 kJ/mol;由CR法拟合结果发现,沼渣热解反应机理为三维扩散模型,为厨余垃圾厌氧沼渣热解资源化再利用提供了重要的基础理论数据。

Regarding to the difficulty of anaerobic biogas residue treatment in the anaerobic fermentation technology of kitchen waste,the pyrolysis kinetics of kitchen waste anaerobic biogas residue was studied on condition that high-purity N2 was used as the carrier gas,the gas flow rate was 50 mL/min,the heating rates of 5,10,15,20,and 30℃/min were selected,and the final pyrolysis temperature was 850℃.The three methods of Flynn-Wall-Ozawa(FWO),KissingerAkahira-Sunose(KAS)and Coats-Redfern(CR)were used to study the effects of ball-milling time and heating rate on the activation energy distribution of biogas slag pyrolysis,and the optimum mechanism function selected by Popescu method was fitted by CR method.The results showed that the pyrolysis process of kitchen waste was divided into three stages;the activation energy calculated by CR method was close to the actual value,ranged from 41.32 to 46.49 kJ/mol.According to the fitting results of CR method,the pyrolysis reaction mechanism of biogas residue was a three-dimensional diffusion model.The research results provided important basic theoretical data for the pyrolysis and resource reuse of kitchen waste anaerobic biogas residue.