Deposition of combustible dust on a hot surface is a hidden danger of fire. In this work, polymethylmethacrylate (PMMA) dust was selected to analyse the influence of dust layer diameter, dust particle size and dust layer thickness on the ignition characteristics of PMMA dust layer. Critical heating temperatures and ignition time had been measured. The STA-GC/MS-FTIR analysis was used to determine that the main products of PMMA pyrolysis were MMA, CO, CO₂, and C₂H₄, of which CO and C₂H₄ were transported to the ambient to cause gas phase combustion on the surface of the dust layer. For 10 mm thick dust layer, the critical heating temperatures of 5 μm PMMA, 100 nm PMMA, and 30 μm PMMA were 300 °C, 330 °C, and 320 °C. As the thickness of the dust layer increased, the gas transport path became longer, the critical heating temperature and ignition time increased. The characteristic particle size (D [3,2]) was utilized to represent the true particle size, and the ignition time increased with the increase of the characteristic particle size. The increase in the diameter of the dust layer had a slight effect on the temperature history and ignition time of the dust layer.

在热表面上沉积可燃粉尘是火灾的隐患。在这项工作中，选择聚甲基丙烯酸甲酯（PMMA）粉尘来分析粉尘层直径，粉尘颗粒大小和粉尘层厚度对PMMA粉尘层着火特性的影响。已测量了临界加热温度和点火时间。使用STA-GC / MS-FTIR分析确定PMMA热解的主要产物为MMA，CO，CO ₂和C ₂ H ₄，其中CO和C ₂ H ₄气体被输送到周围环境，在粉尘层的表面上引起气相燃烧。对于10 mm厚的灰尘层，5μmPMMA，100 nm PMMA和30μmPMMA的临界加热温度分别为300°C，330°C和320°C。随着灰尘层厚度的增加，气体传输路径变长，临界加热温度和点火时间增加。特征粒径（D [3,2]）用于表示真实粒径，并且点火时间随特征粒径的增加而增加。灰尘层直径的增加对灰尘层的温度历史和着火时间影响很小。