燃烧源PM2.5凝结洗涤脱除实验研究

利用蒸汽在燃烧源PM2.5表面凝结，促使PM2.5凝结长大，建立一套燃烧源PM2.5凝结洗涤的实验台；考察了颗粒粒径分布、蒸汽添加量、液气比等对两种燃烧源PM2.5凝结洗涤脱除效果的影响。采用电称低压冲击器 (ELPI)在线测试分析燃煤和燃油PM2.5凝结洗涤前后的数浓度和粒径分布特性，并用SEM和XPS对两种不同燃烧源的颗粒进行了形貌和元素组分分析。结果表明，燃煤和燃油产生的PM2.5形貌和组分具有较大的差别，燃煤PM2.5主要为硅铝矿物质，而燃油PM2.5主要为含炭物质；相同条件下，燃煤PM2.5相变脱除效果优于燃油PM2.5；随着蒸汽添加量的增加，两者的脱除效率均升高；随粒径的增大，脱除效率提高；蒸汽添加量为0.08kg/m3时，粒径为0.4μm的燃煤和燃油细颗粒的脱除效率分别81％和72％；此外，适当增加液气比有利于凝结长大含尘液滴的脱除。

Separation of PM 2.5 from combustion based on vapor condensation and scrubbing

Vapor heterogeneous condensation on the surfaces of PM2.5 was used to increase the removal efficiency of PM2.5 from combustion. An experimental device was set up to investigate the influence of particle initial size distribution, the amount of vapor addition, and the ratio of liquid to gas on removal efficiency. The particle size distribution and concentration at the outlet of scrubber were measured by Electrical Low Pressure Impactor (ELPI). The microstructure and major element compositions of fine particles were explored by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results show that the physico chemical properties of fine particles from coal and oil are very different. And it has considerable influence on heterogeneous nucleation behavior. The removal efficiency of PM2.5 of coal combustion is higher than that of oil. Both number and mass removal efficiencies increase with the increase in particle size and additional amount of vapor. The removal efficiency of 81%and 72% can be achieved for coal and oil combustion of fine particles with particle diameters of 0.4μm at 0.08kg/m3 gas, respectively. Moreover, the collection efficiency can be improved with an appropriate ratio of liquid to gas.