Due to a large particle size and a small specific surface, biomass pellet fragmentation during Chemical looping gasification (CLG) process plays a critical role in the internal devolatilization rate and its conversion. To investigate the mechanical strength evolution of biomass pellet during CLG process, a gasification reactor of bubbling fluidized bed capable of controlling the gasification time arbitrarily is established. Sawdust and rice-husk pellets with different ash content are selected as fuels. More than 720 biomass samples undergoing different gasification time ranging from 15 s to 180 s are collected at different conditions. A porous and brittle morphology of char samples is revealed to be a gradual evolutionary process from the surface to the internal structure during CLG process. Uni-axial compression test shows that the reduction of the peak compressive force for crushing the samples mainly depends on the consumption and destruction of the overall carbon structure including internal skeleton and external epidermis. The penetration of oxygen carrier through pores and/or cracks and the internal overpressure because of rapid volatiles release are the remarkable boosts to the breakage and attrition of the internal carbon skeleton. A corresponding thermal-damage model is developed to predict the mechanical strength of pellet during CLG process.

由于大颗粒尺寸和小比表面积，化学循环气化（CLG）过程中的生物质颗粒破碎对内部脱挥发分率及其转化率起着至关重要的作用。为研究生物质颗粒在CLG过程中机械强度的演变，建立了一种可任意控制气化时间的鼓泡流化床气化反应器。选择不同灰分含量的木屑和稻壳颗粒作为燃料。在不同条件下收集了 720 多个经历不同气化时间的生物质样品，范围从 15 秒到 180 秒。研究表明，在 CLG 过程中，炭样品的多孔和脆性形态是从表面到内部结构的逐渐演化过程。单轴压缩试验表明，粉碎样品的峰值压缩力的降低主要取决于包括内部骨架和外部表皮在内的整体碳结构的消耗和破坏。氧载体通过孔隙和/或裂缝的渗透以及由于快速挥发物释放引起的内部超压是内部碳骨架断裂和磨损的显着促进。开发了相应的热损伤模型来预测 CLG 过程中颗粒的机械强度。氧载体通过孔隙和/或裂缝的渗透以及由于快速挥发物释放引起的内部超压是内部碳骨架断裂和磨损的显着促进。开发了相应的热损伤模型来预测 CLG 过程中颗粒的机械强度。氧载体通过孔隙和/或裂缝的渗透以及由于快速挥发物释放引起的内部超压是内部碳骨架断裂和磨损的显着促进。开发了相应的热损伤模型来预测 CLG 过程中颗粒的机械强度。