Data from: Experiments on torrefied wood pellet – Study by gasification and characterisation for waste biomass to energy applications

Samples of torrefied wood pellet produced by low temperature microwave pyrolysis were tested through a series of experiments relevant to present and near future waste to energy conversion technologies. Operational performance was assessed using a modern small-scale downdraft gasifier. Due to the pellet’s shape and surface hardness, excellent flow characteristics were observed. The torrefied pellet had a high energy density, and although a beneficial property, this highlighted the present inflexibility of downdraft gasifiers in respect of feedstock tolerance due to the inability to contain very high temperatures inside the reactor during operation. Analyses indicated that the torrefaction process had not significantly altered inherent kinetic properties to a great extent; however both activation energy and pre-exponential factor were slightly higher than virgin biomass from which the pellet was derived. TGA-derived reaction kinetics (CO2 gasification), bomb calorimetry, proximate and ultimate analyses, and the Bond Work Index grindability test provided a more comprehensive characterisation of the torrefied pellet’s suitability as a fuel for gasification and also other combustion applications. It exhibited significant improvements in grindability energy demand and particle size control compared to other non-treated and thermally treated biomass pellets, along with a high calorific value, and excellent resistance to water.

本研究针对低温微波热解制备的烘焙木颗粒（torrefied wood pellet）样本，开展了一系列贴合当前及近未来废弃物能源转化技术需求的相关实验。研究采用现代化小型下行床气化炉（downdraft gasifier）对其运行性能进行评估。受该颗粒的形貌与表面硬度影响，其展现出优异的流动特性。该烘焙木颗粒具备较高的能量密度，尽管这是一项有利特性，但也凸显出当前下行床气化炉在原料耐受性方面的显著局限：其无法在运行过程中将反应器内部维持在极高温度水平。分析结果表明，烘焙处理并未在较大程度上显著改变原料固有的反应动力学特性；不过其活化能与指前因子均略高于制备该颗粒的原始生物质。基于热重分析（TGA）的CO₂气化反应动力学、氧弹量热法（bomb calorimetry）、工业分析（proximate analysis）、元素分析（ultimate analysis）以及邦德功指数（Bond Work Index）可磨性试验，可对该烘焙木颗粒作为气化及其他燃烧应用燃料的适用性进行更为全面的表征。相较于其他未处理及经热处理的生物质颗粒，该颗粒在可磨性能耗与粒径控制方面均表现出显著提升，同时拥有较高的热值与优异的抗水性能。