Abstract

In this study, the effects of particle size on combustion kinetics, mechanisms, and decomposition characteristics of five wood samples were examined using thermogravimetric analysis (TGA) under air atmosphere and three different heating rates (10, 40, and 80 °C/min). By using the both Flynn-Wall-Ozawa and Coats-Redfern methods, the highest activation energies were found to be for the coarse samples except untreated pine samples. Only a few studies in the literature investigated the effect of particle size on both thermal kinetics and responsible mechanisms of solid biomass fuels under oxidative environment. Therefore, the findings can be taken into consideration for highly efficient design and operation of industrial thermochemical processes by using waste lignocellulosic biomass as a fuel. In this study, the average activation energies calculated by Flynn-Wall-Ozawa were 166.57, 153.08, and 171.42 kJ/mol for the smallest, medium and coarse samples, respectively. A similar trend but lower values were also evaluated by Coats-Redfern and it was stated as 131.34, 137.52, 146.22 kJ/mol for the smallest, medium, and coarse samples, respectively. As particle size increased lower combustion performance indexes were also obtained. Therefore, in addition to the particle size, the chemical content of the samples also had an impact on the alteration of the kinetic mechanisms and thermal decomposition properties of the samples.

摘要

在本研究中，在空气气氛和三种不同的加热速率（10、40 和 80 °C/min）下，使用热重分析 (TGA) 检查了粒度对五种木材样品的燃烧动力学、机制和分解特性的影响. 通过使用 Flynn-Wall-Ozawa 和 Coats-Redfern 方法，发现除了未经处理的松木样品外，粗糙样品的活化能最高。文献中只有少数研究调查了粒径对氧化环境下固体生物质燃料的热动力学和负责机制的影响。因此，通过使用废弃的木质纤维素生物质作为燃料，可以将这些发现用于工业热化学过程的高效设计和操作。在这项研究中，Flynn-Wall-Ozawa 计算出的最小、中等和粗样品的平均活化能分别为 166.57、153.08 和 171.42 kJ/mol。Coats-Redfern 也评估了类似的趋势但较低的值，最小、中等和粗样品的值分别为 131.34、137.52、146.22 kJ/mol。随着颗粒尺寸的增加，燃烧性能指标也会降低。因此，除粒径外，样品的化学成分也对样品的动力学机制和热分解性能的改变产生影响。最小、中等和粗样品分别为 22 kJ/mol。随着颗粒尺寸的增加，燃烧性能指标也会降低。因此，除粒径外，样品的化学成分也对样品的动力学机制和热分解性能的改变产生影响。最小、中等和粗样品分别为 22 kJ/mol。随着颗粒尺寸的增加，燃烧性能指标也会降低。因此，除粒径外，样品的化学成分也对样品的动力学机制和热分解性能的改变产生影响。