Research On Emission Characteristics And Influencing Factors Of Residential Coal-fired Heating Stoves

Pollutant emission of coal-burned household heating stoves is one of the main contributions of atmospheric air pollution.The emission factors and characteristics of PM2.5,NOx,SO2,and CO of household heating stoves were obtained in the field study and laboratory study.By comparing the analysis of different types of stoves and coal combustion,The influencing factors of pollutant emission of household heating stoves were analyzed by comparing different types of stoves and coal.And it has practical significance for the improvement of combustion efficiency and pollutant emission reduction of new stoves.For the study on the distribution of particulate matter in raw coal and briquette burned in radiant heating stove and water heating stove,a laboratory dilution system was used to measure the emission of particulate matter from two type stoves.It was found that the particulate matter emitted by the stove was mainly spherical organic carbon during the flaming phase,while they were clustered elemental carbon in other phases.The particulates emitted by the combination of raw coal burned in the radiant heating stove during the flaming phase were mostly ultra-fine particles(PM0.2,particle size<0.2 ?m),accounting for 68.97%.In contrast,those in the coal-adding and smoldering phases are mostly 0.2-0.5 ?m particles for 50.6%and 46.6%,respectively.The particulate matter emitted by the briquette burned in the radiant heating stove in the three phases are mainly PM0.2,accounting for 56.24%,54.62%,and 44.64%,respectively.The briquette burned in the water heating stove mainly emits PM0.2-0.5 in the flaming phase,accounting for 40.43%.And it mainly emits PM0.2 in the smoldering phase,accounting for 37.9%.After fitting the curve through the R-R distribution,it is found that the briquette has a certain effect in reducing the emission of ultra-fine particles.At the same time,frequent coal-addition and stove-observation will cause instantaneous fluctuations of PM2.5.The coal types and qualities are the main factors affecting gaseous pollutants emission.Compared to raw coal,briquette can reduce the emission factor of NOx during the flaming phase,but has higher emission factors of CO,SO2,and PM2.5.Furthermore,raw coal replaced by briquette reduces NOx for 69%,but the emissions of CO,PM2.5 and SO2 increase 116%,94%,and 12%,respectively.Compared to raw coal,briquette can reduce the emission factors of PM2.5 and NOx during the smoldering phase,but has higher emission factors of CO and SO2;raw coal replaced by briquette reduces the emissions of PM2.5 and NOx by 87%and 51%.The increase in CO and SO2 emissions are 139%and 11%,respectively.In order to further investigate impact of different fuels on stove pollutant emissions.Biomass pellets,biomass briquettes,anthracite briquettes,bituminous briquettes,semi-coke,and briquette were tested in this study.The average SO2 emission factor of biomass stove is 1.17±1.09 g/kg,while the coal-burning stove is 3.05±4.02 g/kg,which is 2.6 times high.Meanwhile,NOx,PM2.5,and CO emission factors of the raw coal burned in biomass stoves were significantly higher than the raw coal burned in raw coal adapted stoves.This indicates that the pollutant emissions of unsuitable stoves have a greater impact on the environment.Compared to raw coal,semi-coke increased SO2 emissions by 466%and NOx emissions by 177%,while briquette increased CO emissions by 77%compared to raw coal.Also,compared to raw coal,straw pellets have a 71.3%reduction in CO emissions,but increasing 66.2%of SO2 emissions,while reducing 16.3%of NOx emissions.Furthermore,biomass briquette has higher PM2.5 and SO2 emissions,which are 16.25 times and 5.88 times of straw pellets,respectively.The results show that suitable of stoves and fuels is a prerequisite for pollutant emissions reduction,and high-quality fuel is the key to pollutant emissions reduction.In the field test,it is found that the operation habits of the stoves in different areas are generally similar by analyzing the emission characteristics of different stoves and fuels.But there will be certain differences because of the different types of stoves.Radiant heating stove's users are accustomed to performing multiple operations on stoves:coal-adding,ignition and cooking operation,etc.These operating habits will greatly influence the pollutant emissions.Meanwhile,the short-time flaming phase and long-time smoldering phase caused higher CO and PM2.5 emissions,and the fugitive emissions of CO at night threaten human health.Most water heating stove's users place the stove in the kitchen and do not cook on that,but only perform water-burning activities.Compared to radiant heating stove's users,water heating stove's users rarely perform coal addition operations,and most water heating stoves are equipped with bunkers,which can effectively reduce pollution emissions during the coal-adding phase.