Characteristics Of Condensable Particulate Matter Discharging From A One-dimensional Flame Furnace Firing Typical Coals

Particulate matter emitted by fuel combustion is the main atmospheric pollutant,including filterable particulate matter(FPM)and condensable particulate matter(CPM).In the past,because of the large amount of FPM emissions,people's attention was focused on FPM,so that its control technology has been developed rapidly.At present,FPM has been well controlled,and its emission concentration can achieve ultra-low emission indicators(not exceeding 5mg/Nm3).On the contrary,the emission concentration of CPM that has not been paid enough attention to is now higher than FPM,so CPM cannot be ignored anymore.Therefore,people are paying more and more attention to CPM.CPM is a particulate matter that is quickly formed by some gaseous substances in the flue gas after discharging,and belongs to the primary particulate matter emitted into the atmosphere by stationary sources.At present,people's understanding of CPM is still very lacking,so this work has summarized the current status of CPM research based on existing literature,helping people understand CPM from many aspects.The concept,formation mechanism,and hazards of CPM were analyzed in this work.The sampling methods of CPM were introduced and the interference factors and improvement measures were also discussed.Moreover,the characteristics of the CPM were summarized.There have been many CPM researches conducted on industrial emission sources,which mainly focus on the CPM emission characteristics and the CPM migration characteristics in pollutant control equipment.There is a lack of research on the initial characteristics of CPM in the flue gas from fuel combustion.This work may be the first attempt to explore the characteristics of CPM in actual flue gas from bench-scale combustion equipment.Stably generating actual flue gas containing CPM in a small flow rate is challenging,and this work successfully achieved it through building a one-dimensional coal combustion system.Through the combustion of Inner Mongolian lignite in this system,a large amount of emission characteristic data was obtained.The effects of combustion conditions and flue gas sampling temperature were explored based on CPM measurement data.The characteristics of water-soluble ions and metal elements in CPM inorganic components were analyzed.The main CPM organic components were also summarized.Besides,droplet-and fragment-shaped condensed CPM particles were observed on the filter membrane through a scanning electron microscope.By firing three typical coals(Inner Mongolian lignite,Jinjie bitumite,and Ningxia anthracite)in this one-dimensional flame furnace system,the emission characteristic data was studied comparatively,including CPM concentration,water-soluble ions,metal elements,and organic components.The difference in CPM characteristic data obtained by different coal under various combustion conditions were thoroughly analyzed.Furthermore,the SEM-EDS technology was used to obtain the morphology features and elemental composition of CPM trapped on the filter membrane of different coals.The heavy metals(such as Hg,As,Se,Sb)were also found in the CPM trapped on the filter membrane.These valuable data will enrich people's understanding of the characteristics of CPM generated by coal combustion.Also,this work can provide references for the future research on CPM governance and the environmental damage assessment.