scholarly journals Characteristics of Spherical Organic Particles Emitted from Fixed-Bed Residential Coal Combustion

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 441
Author(s):  
Tafadzwa Makonese ◽  
Johan Meyer ◽  
Sune von Solms
Keyword(s):  
Coal Combustion ◽  
Regional Climate ◽  
Fixed Bed ◽  
Research Centre ◽  
Biomass Combustion ◽  
Formation Mechanisms ◽  
Carbonaceous Aerosols ◽  
Coal Burning ◽  
Organic Particles ◽  
Residential Coal

Residential coal combustion is one of the most significant sources of carbonaceous aerosols in the Highveld region of South Africa, significantly affecting the local and regional climate. This study investigated single coal-burning particles emitted when using different fire-ignition techniques (top-lit up-draft versus bottom-lit up-draft) and air ventilation rates (defined by the number of air holes above and below the fire grate) in selected informal braziers. Aerosol samples were collected on nucleopore filters at the Sustainable Energy Technology and Research Centre Laboratory, University of Johannesburg. The individual particles (~700) were investigated using a scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (EDX). Two distinct forms of spherical organic particles (SOPs) were identified, one less oxidized than the other. The particles were further classified into electronically dark and bright. The EDX analysis showed that 70% of the dark spherical organic particles had higher (~60%) relative oxygen content than in the bright SOPs. The morphology of spherical organic particles were quantified and classified into four categories: ~50% were bare single particles; ~35% particles were aggregated and formed diffusion accretion chains; 10% had inclusions, and 5% were deformed due to impaction on filter material during sampling. This study concludes that there are two distinct kinds of coal burning spherical organic particles and that dark SOPs are less volatile than bright SOPs. The authors also show that these spherical organic particles are similar in nature and characteristics to tar balls observed in biomass combustion and that they have the potential to absorb sunlight thereby affecting the earth’s radiative budget and climate. This study provides insights into the mixing states, morphology, and possible formation mechanisms of these organic particles from residential coal combustion in informal stoves.

scholarly journals Characteristics of Spherical Organic Particles Emitted from Fixed-Bed Residential Coal Combustion

2019 ◽  
Author(s):  
Tafadzwa Makonese ◽  
Johan Meyer ◽  
Sune Von Solms
Keyword(s):  
Coal Combustion ◽  
Regional Climate ◽  
Fixed Bed ◽  
Research Centre ◽  
Biomass Combustion ◽  
Formation Mechanisms ◽  
Carbonaceous Aerosols ◽  
Coal Burning ◽  
Organic Particles ◽  
Residential Coal

Residential coal combustion is one of the most significant sources of carbonaceous aerosols in the Highveld region of South Africa, significantly affecting the local and regional climate. In this study, we investigated single coal-burning particles emitted when using different fire-ignition techniques (top-lit up-draft vs bottom-lit up-draft) and air ventilation rates (defined by the number of air holes above and below the fire grate) in selected informal braziers. Aerosol samples were collected on nucleopore filters at the Sustainable Energy Technology and Research Centre Laboratory, University of Johannesburg. Individual particles (~700) were investigated using a scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (EDS). Two distinct forms of spherical organic particles (SOPs) were identified, one less oxidized than the other. The particles were further classified into "electronically" dark and bright. EDS analysis showed that 70% of the dark spherical organic particles had higher (~60%) relative oxygen content than in the bright SOPs. We quantified the morphology of spherical organic particles and classified them into four categories: ~50% are bare single particles; ~35% particles are aggregated and form diffusion accretion chains; 10% have inclusions, and 5% are deformed due to impaction on filter material during sampling. We conclude that there are two distinct kinds of coal burning spherical organic particles and that dark SOPs are less volatile than bright SOPs. We also show that these spherical organic particles are similar in nature and characteristics to tar balls observed in biomass combustion and that they have the potential to absorb sunlight thereby affecting the earth’s radiative budget and climate. This study provides insights into the mixing states, morphology, and possible formation mechanisms of these organic particles from residential coal combustion in informal stoves.

scholarly journals Quantifying primary and secondary humic-like substances in urban aerosol based on emission source characterization and a source-oriented air quality model

2018 ◽  
Author(s):  
Xinghua Li ◽  
Junzan Han ◽  
Philip K. Hopke ◽  
Jingnan Hu ◽  
Qi Shu ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Biomass Burning ◽  
Coal Combustion ◽  
Power Plants ◽  
Water Soluble ◽  
Aerosol Formation ◽  
Source Characterization ◽  
Air Quality Model ◽  
Coal Burning ◽  
Residential Coal

Abstract. Humic-like substances (HULIS) are a mixture of high molecular weight, water-soluble organic compounds that are widely distributed in atmospheric aerosol. Their sources are rarely studied quantitatively. Biomass burning is generally accepted as a major primary source of ambient humic-like substances (HULIS) with additional secondary material formed in the atmosphere. However, the present study provides direct evidence that residential coal burning is also a significant source of ambient HULIS, especially in the heating season in northern China based on source measurements, ambient sampling and analysis, and apportionment with source-oriented CMAQ modeling. Emissions tests show that residential coal combustion produces 5 to 24 % of the emitted organic carbon (OC) as HULIS carbon (HULISc). Estimation of primary emissions of HULIS in Beijing indicated that residential biofuel and coal burning contribute about 70 % and 25 % of annual primary HULIS, respectively. Vehicle exhaust, industry, and power plants contributions are negligible. Average concentration of ambient HULIS was 7.5 μg/m3 in atmospheric PM2.5 in urban Beijing and HULIS exhibited obvious seasonal variations with the highest concentrations in winter. HULISc account for 7.2 % of PM2.5 mass, 24.5 % of OC, and 59.5 % of water-soluble organic carbon, respectively. HULIS are found to correlate well with K+, Cl−, sulfate, and secondary organic aerosol suggesting its sources include biomass burning, coal combustion and secondary aerosol formation. Source apportionment based on CMAQ modeling shows residential biofuel and coal burning, secondary formation are important annual sources of ambient HULIS, contributing 57.5 %, 12.3 %, and 25.8 %, respectively.

scholarly journals Sources and formation of carbonaceous aerosols in Xi'an, China: primary emissions and secondary formation constrained by radiocarbon

2020 ◽  
Author(s):  
Haiyan Ni ◽  
Ru-Jin Huang ◽  
Ulrike Dusek
Keyword(s):  
Biomass Burning ◽  
Coal Combustion ◽  
Vehicle Emissions ◽  
Fossil Fuel ◽  
Fuel Combustion ◽  
Warm Period ◽  
Water Soluble ◽  
Formation Mechanisms ◽  
Carbonaceous Aerosols ◽  
Fossil Fuel Combustion

<p>To investigate the sources and formation mechanisms of carbonaceous aerosols, a major contributor to severe particulate air pollution, radiocarbon (<span><sup>14</sup>C</span>) measurements were conducted on aerosols sampled from November 2015 to November 2016 in Xi'an, China. Based on the <span><sup>14</sup>C</span> content in elemental carbon (EC), organic carbon (OC) and water-insoluble OC (WIOC), contributions of major sources to carbonaceous aerosols are estimated over a whole seasonal cycle: primary and secondary fossil sources, primary biomass burning, and other non-fossil carbon formed mainly from secondary processes. Primary fossil sources of EC were further sub-divided into coal and liquid fossil fuel combustion by complementing <span><sup>14</sup>C</span> data with stable carbon isotopic signatures.</p><p>The dominant EC source was liquid fossil fuel combustion (i.e., vehicle emissions), accounting for 64 % (median; 45 %–74 %, interquartile range) of EC in autumn, 60 % (41 %–72 %) in summer, 53 % (33 %–69 %) in spring and 46 % (29 %–59 %) in winter. An increased contribution from biomass burning to EC was observed in winter (<span>∼28</span> %) compared to other seasons (warm period; <span>∼15</span> %). In winter, coal combustion (<span>∼25</span> %) and biomass burning equally contributed to EC, whereas in the warm period, coal combustion accounted for a larger fraction of EC than biomass burning. The relative contribution of fossil sources to OC was consistently lower than that to EC, with an annual average of <span>47±4</span> %. Non-fossil OC of secondary origin was an important contributor to total OC (<span>35±4</span> %) and accounted for more than half of non-fossil OC (<span>67±6</span> %) throughout the year. Secondary fossil OC (SOC<span><sub>fossil</sub></span>) concentrations were higher than primary fossil OC (POC<span><sub>fossil</sub></span>) concentrations in winter but lower than POC<span><sub>fossil</sub></span> in the warm period.</p><p>Fossil WIOC and water-soluble OC (WSOC) have been widely used as proxies for POC<span><sub>fossil</sub></span> and SOC<span><sub>fossil</sub></span>, respectively. This assumption was evaluated by (1) comparing their mass concentrations with POC<span><sub>fossil</sub></span> and SOC<span><sub>fossil</sub></span> and (2) comparing ratios of fossil WIOC to fossil EC to typical primary OC-to-EC ratios from fossil sources including both coal combustion and vehicle emissions. The results suggest that fossil WIOC and fossil WSOC are probably a better approximation for primary and secondary fossil OC, respectively, than POC<span><sub>fossil</sub></span> and SOC<span><sub>fossil</sub></span> estimated using the EC tracer method.</p>

scholarly journals Sources and formation of carbonaceous aerosols in Xi'an, China: primary emissions and secondary formation constrained by radiocarbon

2019 ◽  
Vol 19 (24) ◽  
pp. 15609-15628 ◽  
Author(s):  
Haiyan Ni ◽  
Ru-Jin Huang ◽  
Junji Cao ◽  
Jie Guo ◽  
Haoyue Deng ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Coal Combustion ◽  
Vehicle Emissions ◽  
Fossil Fuel ◽  
Fuel Combustion ◽  
Warm Period ◽  
Water Soluble ◽  
Formation Mechanisms ◽  
Carbonaceous Aerosols ◽  
Fossil Fuel Combustion

Abstract. To investigate the sources and formation mechanisms of carbonaceous aerosols, a major contributor to severe particulate air pollution, radiocarbon (14C) measurements were conducted on aerosols sampled from November 2015 to November 2016 in Xi'an, China. Based on the 14C content in elemental carbon (EC), organic carbon (OC) and water-insoluble OC (WIOC), contributions of major sources to carbonaceous aerosols are estimated over a whole seasonal cycle: primary and secondary fossil sources, primary biomass burning, and other non-fossil carbon formed mainly from secondary processes. Primary fossil sources of EC were further sub-divided into coal and liquid fossil fuel combustion by complementing 14C data with stable carbon isotopic signatures. The dominant EC source was liquid fossil fuel combustion (i.e., vehicle emissions), accounting for 64 % (median; 45 %–74 %, interquartile range) of EC in autumn, 60 % (41 %–72 %) in summer, 53 % (33 %–69 %) in spring and 46 % (29 %–59 %) in winter. An increased contribution from biomass burning to EC was observed in winter (∼28 %) compared to other seasons (warm period; ∼15 %). In winter, coal combustion (∼25 %) and biomass burning equally contributed to EC, whereas in the warm period, coal combustion accounted for a larger fraction of EC than biomass burning. The relative contribution of fossil sources to OC was consistently lower than that to EC, with an annual average of 47±4 %. Non-fossil OC of secondary origin was an important contributor to total OC (35±4 %) and accounted for more than half of non-fossil OC (67±6 %) throughout the year. Secondary fossil OC (SOCfossil) concentrations were higher than primary fossil OC (POCfossil) concentrations in winter but lower than POCfossil in the warm period. Fossil WIOC and water-soluble OC (WSOC) have been widely used as proxies for POCfossil and SOCfossil, respectively. This assumption was evaluated by (1) comparing their mass concentrations with POCfossil and SOCfossil and (2) comparing ratios of fossil WIOC to fossil EC to typical primary OC-to-EC ratios from fossil sources including both coal combustion and vehicle emissions. The results suggest that fossil WIOC and fossil WSOC are probably a better approximation for primary and secondary fossil OC, respectively, than POCfossil and SOCfossil estimated using the EC tracer method.

scholarly journals Quantifying primary and secondary humic-like substances in urban aerosol based on emission source characterization and a source-oriented air quality model

2019 ◽  
Vol 19 (4) ◽  
pp. 2327-2341 ◽  
Author(s):  
Xinghua Li ◽  
Junzan Han ◽  
Philip K. Hopke ◽  
Jingnan Hu ◽  
Qi Shu ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Biomass Burning ◽  
Coal Combustion ◽  
Water Soluble ◽  
Aerosol Formation ◽  
Source Characterization ◽  
Air Quality Model ◽  
Quality Model ◽  
Coal Burning ◽  
Residential Coal

Abstract. Humic-like substances (HULIS) are a mixture of high-molecular-weight, water-soluble organic compounds that are widely distributed in atmospheric aerosol. Their sources are rarely studied quantitatively. Biomass burning is generally accepted as a major primary source of ambient humic-like substances (HULIS) with additional secondary material formed in the atmosphere. However, the present study provides direct evidence that residential coal burning is also a significant source of ambient HULIS, especially in the heating season in northern China based on source measurements, ambient sampling and analysis, and apportionment with source-oriented CMAQ modeling. Emission tests show that residential coal combustion produces 5 % to 24 % of the emitted organic carbon (OC) as HULIS carbon (HULISc). Estimation of primary emissions of HULIS in Beijing indicated that residential biofuel and coal burning contribute about 70 % and 25 % of annual primary HULIS, respectively. Vehicle exhaust, industry, and power plant contributions are negligible. The average concentration of ambient HULIS in PM2.5 was 7.5 µg m−3 in urban Beijing and HULIS exhibited obvious seasonal variations with the highest concentrations in winter. HULISc accounts for 7.2 % of PM2.5 mass, 24.5 % of OC, and 59.5 % of water-soluble organic carbon. HULIS are found to correlate well with K+, Cl−, sulfate, and secondary organic aerosol, suggesting its sources include biomass burning, coal combustion, and secondary aerosol formation. Source apportionment based on CMAQ modeling shows residential biofuel and coal burning and secondary formation are important sources of ambient HULIS, contributing 47.1 %, 15.1 %, and 38.9 %, respectively.

scholarly journals Sources and formation of carbonaceous aerosols in Xi'an, China: primary emissions and secondary formation constrained by radiocarbon

2019 ◽  
Author(s):  
Haiyan Ni ◽  
Ru-Jin Huang ◽  
Junji Cao ◽  
Jie Guo ◽  
Haoyue Deng ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Coal Combustion ◽  
Vehicle Emissions ◽  
Fossil Fuel ◽  
Fuel Combustion ◽  
Warm Period ◽  
Formation Mechanisms ◽  
Carbonaceous Aerosols ◽  
Fossil Fuel Combustion ◽  
Relative Contribution

Abstract. To investigate the sources and formation mechanisms of carbonaceous aerosols, a major contributor to severe particulate air pollution, radiocarbon (14C) measurements were conducted on aerosols sampled from November 2015 to November 2016 in Xi'an, China. Based on the 14C content in elemental carbon (EC), organic carbon (OC) and water-insoluble OC (WIOC), contributions of major sources to carbonaceous aerosols are estimated over a whole seasonal cycle: primary and secondary fossil sources, primary biomass burning, and other non-fossil carbon formed mainly from secondary processes. Primary fossil sources of EC were further sub-divided into coal and liquid fossil fuel combustion by complementing 14C data with stable carbon isotopic signatures. The dominant EC source was liquid fossil fuel combustion (i.e., vehicle emissions), accounting for 64 % (median; 45–74 %, interquartile range) of EC in autumn, 60 % (41–72 %) in summer, 53 % (33–69 %) in spring and 46 % (29–59 %) in winter, respectively. An increased contribution from biomass burning to EC was observed in winter (~ 28 %) compared to other seasons (warm period; ~ 15 %). In winter, coal combustion (~ 25 %) and biomass burning equally contributed to EC, whereas in the warm period, coal combustion accounted for a larger fraction of EC than biomass burning. The relative contribution of fossil sources to OC was consistently lower than that to EC, with an annual average of 47 ± 4 %. Non-fossil OC of secondary origin was an important contributor to total OC (35 ± 4%) and accounted for more than half of non-fossil OC (67 ± 6%) throughout the year. Secondary fossil OC (SOCfossil) concentrations were higher than primary fossil OC (POCfossil) concentrations in winter, but lower than POCfossil in the warm period. Fossil WIOC and water-souble OC (WSOC) have been widely used as proxies for POCfossil and SOCfossil, respectively. This assumption was evaluated by (1) comparing their mass concentrations with POCfossil and SOCfossil, and (2) comparing ratios of fossil WIOC to fossil EC to typical primary OC to EC ratios from fossil sources including both coal combustion and vehicle emissions. The results suggest that fossil WIOC and fossil WSOC are probably a better approximation for primary and secondary fossil OC, respectively, than POCfossil and SOCfossil estimated using the EC tracer method.

Isotope signatures of atmospheric mercury emitted from residential coal combustion

2020 ◽  
pp. 118175
Author(s):  
Xinyu Li ◽  
Zhonggen Li ◽  
Ji Chen ◽  
Leiming Zhang ◽  
Runsheng Yin ◽  
...  
Keyword(s):  
Coal Combustion ◽  
Atmospheric Mercury ◽  
Residential Coal

The Effect of Dolomite Addictive Ratio on Torrified Cassava Rhizome in the Biomass Combustion Process

2021 ◽  
Vol 407 ◽  
pp. 113-120
Author(s):  
Nat Thuchayapong ◽  
Nattawut Tharawadee
Keyword(s):  
Combustion Process ◽  
Fixed Bed ◽  
Air Pressure ◽  
Biomass Combustion ◽  
Optimum Ratio ◽  
Bomb Calorimeter ◽  
Useful Heat ◽  
Main Component ◽  
The Cost ◽  
Research Studies

This research studies on the effect of additive (Dolomite) on Biomass powder (Cassava rhizome) which passes Torrefied process and fixed bed at 250 degrees Celsius for one hour and a half. The gasifier with up-draft type was used in this experiment. Air pressure was fixed at 0.1 Bar. The useful heat (Quseful) and Low heating valves (LHV) was investigated by using an Automatic Bomb Calorimeter. Moreover, the dolomite was varied 0, 10 and 15% by weight mixed with Cassava rhizome achieved with Torrefied process. When Low heating valves (LHV) slightly decreases from 21.96±0.22 MJ/kg to 18.15±0.50 MJ/kg, Quseful heat from the burning from gasifier sharply increase when it is mixed with dolomite from 753.34±39.18 to 1,003.97±33.49KJ respectively. The loading of dolomite has significance affecting the useful heat. The present study reveals that low heating valves (LHV) decreases and Quseful heat increase result from dolomite which gives a clean gas product and the Tar molecule can be easily broken. The CO2 gas from the combustion process was absorbed by CaO, which is the main component in dolomite. The cost of mixing 8.9% of Dolomite with Cassava rhizome is the optimum ratio for the biomass combustion process.

scholarly journals Emission of PM2.5-Bound Polycyclic Aromatic Hydrocarbons from Biomass and Coal Combustion in China

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1129
Author(s):  
Xinghua Li ◽  
Zihao Wang ◽  
Tailun Guo
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Mass Balance ◽  
Aromatic Hydrocarbons ◽  
Coal Combustion ◽  
Emission Factors ◽  
Chemical Mass Balance ◽  
Open Burning ◽  
Coal Burning ◽  
Receptor Modelling ◽  
Polycyclic Aromatic

Field measured PAH emissions from diverse sources in China are limited or even not available. In this study, the PM2.5-bound PAH emission factors (EFs) for typical biomass and coal combustion in China were determined on-site. The measured total PAH EFs were 24.5 mg/kg for household coal burning, 10.5–13.9 mg/kg for household biofuel burning, 8.1–8.6 mg/kg for biomass open burning, and 0.021–0.31 mg/kg for coal-fired boilers, respectively. These EF values were compared with previous studies. The sources profiles of PAHs for four sources were developed to use in chemical mass balance receptor modelling. BaP equivalent EFs (EFBaPeq) were calculated to evaluate PAH emission toxicity among different combustion sources, and were 6.81, 2.94–4.22, 1.59–3.62, and 0.0006–0.042 mg/kg for those four types of sources, respectively.

The Changes of PM2.5, BC, Elements and Pollution Sources Using Nuclear Technology in Xinzhen, Beijing Over the Past Decade

2021 ◽  
Author(s):  
Junkai Yang ◽  
Yonggang Yao ◽  
Hui Zhang ◽  
Yangmei Zhang ◽  
Caijin Xiao ◽  
...  
Keyword(s):  
Coal Combustion ◽  
High Sensitivity ◽  
Waste Incineration ◽  
Pollution Sources ◽  
Biomass Combustion ◽  
Combustion Source ◽  
Sources Of Pollution ◽  
Initial Stage ◽  
Coal Boiler ◽  
Autumn And Winter

Abstract The concentrations of PM2.5, black carbon (BC), elements as well as sources of pollution in Beijing from 2003 to 2018 were investigated. The results show that the concentrations of PM2.5 and BC had similar annual and seasonal trends, especially in autumn-winter, which with declining trends in recent years. The proportion of BC in PM2.5 reduced from 13% in 2013(max) to 8.5% in 2018(min), indicating the reducing measure of replacing coal boiler with gas boilers worked well. In this study, annual trends of 15 elements were also discussed, it is found that the concentrations of S, K, Mn, Ca, Pb, Cu, Mn and Fe displayed remarkable decrease these years. Br, Zn and Cl was growing overall and Cl was more concentrated in PM2.5 in autumn and winter. Moreover, the In detected by NAA with high sensitivity may be a new and crucial fingerprint element associated with coal combustion, industry emission or biomass combustion because of correlation with BC, Na, K, Cu and halogen elements well. Finally, 6-factor solution was identified during 2007 and 2016-2017 by EPA PMF, and the proportions of some pollution sources changed a lot in PM2.5. Soil management in north China reduced the soil and dust source by 9.2%; The contribution of Industry-S or secondary S showed decrease from 27.5% to 22.5% due to industries relocating , gasoline with sulfur optimization and coal burning restriction; Banning straw burning and waste incineration in 2007 kept biomass and waste combustion out gradually. However, initial stage of some policies maybe the main reasons for a small increase of coal combustion source despite some steps taken.

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