| For a long time,solid fuels have provided power for human production and life,but it has also caused negative effects on the atmosphere environment and human health.Existing studies on stoves and solid fuels mainly focus on the emission of PM2.5 and changes in its chemical composition,while there are relatively few studies on particle size distribution,especially ultrafine particles.In order to study the characteristics of the particulate matter emission and particle size distribution of stoves,based on the fume hood dilution system and user habits,three typical coal samples of bituminous coal,bituminous briquette coal and anthracite briquette coal,as well as reverse burning coal stove,normal burning coal stove,gravity-fed biomass stove and power-fed biomass stove,were tested to discuss the PM2.5 emission and particle size distribution.Three factors of combustion chamber temperature,coal charging amount,and fuel particle size were quantified to discuss the influence of PM2.5 emissions and particle size distribution for "bituminous coal+radiant heating stove".The results provide data support for the government’s clean heating policy and the design of fuels and stoves.There is no significant difference between the three fuel emission factors at the high and low power levels.The emission factors of the three fuels in descending order are bituminous briquette coal,bituminous coal,and anthracite briquette coal,respectively 8.96±1.09,2.82±0.44,and 0.07±0.00 g/kg at high power levels.The number of particulate matters in bituminous briquette and bituminous coal has a unimodal distribution with a peak particle size of 0.009μm,accounting for 90.74%and 99.28%of the total particle number,respectively.Anthracite briquette coal has a bimodal distribution with peak particle sizes of 0.009 μm and 0.028 μm,accounting for 44.22%and 20.14%of the total particle size,respectively.The median mass particle size of the three fuels at high power was 0.660 μm,0.531 μm and 0.845μm,respectively.The quantity and mass ratio of particles with small particle size can be effectively reduced by making coal from raw coal or using fuel with lower volatile content.Under high and low power,the emission factors of normal burning coal stove are 6.28±0.51 and 8.93±1.29 g/kg and the reverse burning design can reduce the emission factors of PM2.5 by 67%and 74%,respectively.But the reverse burning design will increase the quantity and mass ratio of small particle size.Under the high power,the power feeding and gravity feeding methods will not significantly affect the PM2.5 emission factor of the semi-gasified biomass stove,which are 0.16±0.01 and 0.18±0.04 g/kg,respectively.However,the power feeding method can increase the emission of particles with small particle size.In addition,it is difficult to be in the gasification combustion state under low power,which increases the PM2.5 emission factor by 11.38 times.The influence of the three factors on the PM2.5 emission factor is in the order of stove temperature>fuel particle size>coal charging amount,only the stove temperature is significant at the level of α=0.1.In terms of particulate matter emissions,the fuel particle size has the greatest impact on the emissions of particulate matter with a particle size of less than 0.1μm,and the combustion chamber temperature has the greatest impact on the emissions of particulate matter with a particle size of 0.1-1 μm;in terms of particle surface area emission,fuel particle size had the greatest impact on the emissions of particulate matter with a particle size of 0-0.01μm,and combustion chamber temperature had the greatest impact on the emissions of particulate matter with a particle size of 0.01-1μm;in terms of particulate matter mass emissions,fuel particle size has the greatest impact on particulate matter emissions with a particle size of 0-0.01 μm and 0.1-1μm,the combustion chamber temperature has the greatest impact on the emission of particles with a particle size of 0.01-0.1μm. |
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