南京理工大学张睿团队报道了不同O₂/CO₂/H₂O气氛下mAl颗粒在流化床中的燃烧特性。相关研究成果于2024年4月19日发表在《颗粒学报》。

铝是一种有吸引力的替代燃料，但由于形成了致密的Al₂O₃层，阻止了O₂扩散到Al颗粒的表面，因此其燃烧效率非常低。在之前的实验中，毫米大小的Al（mAl）颗粒在流化床中的燃烧已经实现了燃烧效率的显著提高，但仍需要进一步的改进。

该研究中，研究了反应气氛对mAl颗粒流化燃烧的影响。进行了不同O₂/H₂O/CO₂浓度的实验。实验结果表明，随着O₂、H₂O或CO₂摩尔分数的增加，mAl颗粒在流化床中的燃烧效率增加，最高燃烧效率可达38.7%。

对铝颗粒表面的氧化膜进行分析后发现，在CO₂气氛下更容易产生不稳定的θ-Al₂O₃，在H₂O气氛下更易于产生不稳定性的γ-Al₂O₃和θ-Al₂O₃。不稳定的Al₂O₃膜在流化床中更容易被磨损，从而有效地提高了燃烧效率。

附：英文原文

Title: Combustion characteristics of millimeter-sized aluminum particles in fluidized bed under various O2/CO2/H2O atmospheres

Author: Rui Zhang

Issue&Volume: 2024/04/19

Abstract: Aluminum is an attractive alternative fuel, but it burns very inefficiently due to the formation of a dense Al2O3 layer which prevents O2 from diffusion to the surface of Al particles. In previous experiments, the combustion of millimeter-sized Al (mAl) particles in the fluidized bed has achieved a substantial increase in the combustion efficiency, but further improvements are still needed. In this study, the effects of reaction atmosphere on the fluidized combustion of mAl particles were investigated. The experiments with different O2/H2O/CO2 concentrations were conducted. The experimental results indicate that the combustion efficiency of mAl particles in fluidized bed increases as the mole fraction of O2, H2O or CO2 increases, and the highest combustion efficiency can reach 38.7%. After the analysis of the oxide film on the surface of aluminum particles, it was found that it is easier to generate the unstable θ-Al2O3 under CO2 atmosphere, and it is easier to generate the unstable γ-Al2O3 and θ-Al2O3 under H2O atmosphere. 

DOI: 10.1016/j.partic.2024.04.003

Source: https://www.sciencedirect.com/science/article/abs/pii/S1674200124000579