scholarly journals Influence of coal properties on the performance of fixed-bed coal-burning braziers

2017 ◽  
Vol 28 (2) ◽  
pp. 40 ◽  
Author(s):  
Tafadzwa Makonese ◽  
Daniel M. Masekameni ◽  
Harold J. Annegarn
Keyword(s):  
Moisture Content ◽  
Low Income ◽  
Co2 Emission ◽  
Fixed Bed ◽  
Combustion Efficiency ◽  
Emission Factors ◽  
Coal Burning ◽  
Air Ventilation ◽  
Carbon Dioxide Co2 ◽  
Ventilation Rates

Informal fixed-bed coal-burning braziers are used extensively in low-income communities of South Africa for space-heating and cooking needs. An investigation was carried out on the effects of coal moisture content and coal quality on the thermal and emissions performance of domestic coal-burning braziers in three field-procured braziers (with three different air ventilation rates), using the bottom-lit updraft (BLUD) and top-lit updraft (TLUD) ignition methods. Results showed that an increase in coal moisture content (from 2.4 wt.% to 8.6 wt.%) led to 18% and 30% decreases in fire-power when using the TLUD and BLUD methods, respectively. The combustion efficiency increased by 25% with an increase in moisture content. Measured carbon monoxide (CO) emission factors increased with an increase in moisture content, while carbon dioxide (CO2) emission factors remained unchanged. The use of A-grade coal resulted in a 49% increase in PM emissions compared with D-grade coal at high ventilation rates, despite no statistically significant differences (p > 0.05) in CO and CO2 emission factors produced between coal grades.

The influence of fuel moisture content on the combustion of Eucalyptus foliage

2013 ◽  
Vol 22 (3) ◽  
pp. 343 ◽  
Author(s):  
Malcolm Possell ◽  
Tina L. Bell
Keyword(s):  
Moisture Content ◽  
Dry Weight ◽  
Co2 Concentration ◽  
Combustion Products ◽  
Combustion Efficiency ◽  
Emission Factors ◽  
Fuel Moisture ◽  
Time To Ignition ◽  
Fuel Moisture Content ◽  
Co Concentrations

Leaves from three species of Eucalyptus were combusted in a mass-loss calorimeter to characterise the effect of fuel moisture on energy release and combustion products for this genus. Increasing moisture content reduced peak heat release and the effective heat of combustion in a negative exponential pattern while simultaneously increasing time-to-ignition. Estimates of the probability of ignition, based upon time-to-ignition data, indicated that the critical fuel moisture content for a 50% probability of ignition ranged from 81 to 89% on a dry-weight basis. The modified combustion efficiency of leaves (the ratio of CO2 concentration to the sum of the CO2 and CO concentrations) decreased exponentially as fuel moisture increased. This was because CO2 concentrations during combustion declined exponentially while CO concentrations increased exponentially. However, CO2 mixing ratios were always greater by at least one order of magnitude. Emission factors for CO2 declined exponentially with increasing fuel moisture content while CO emission factors increased exponentially to a maximum. The emission factors for volatile organic compounds increased in a pattern similar to that for CO with increasing fuel moisture content. The empirical relationships identified in this study have implications for fire-behaviour modelling and assessing the effect of fire on air quality and climate.

Grassland and forest understorey biomass emissions from prescribed fires in the south-eastern United States – RxCADRE 2012

2016 ◽  
Vol 25 (1) ◽  
pp. 102 ◽  
Author(s):  
Tara Strand ◽  
Brian Gullett ◽  
Shawn Urbanski ◽  
Susan O'Neill ◽  
Brian Potter ◽  
...  
Keyword(s):  
Forest Biomass ◽  
Combustion Efficiency ◽  
Emission Factors ◽  
Prescribed Fires ◽  
Eastern United States ◽  
Smoke Plumes ◽  
Forest Understorey ◽  
Carbon Dioxide Co2 ◽  
Modified Combustion Efficiency ◽  
Smouldering Combustion

Smoke measurements were made during grass and forest understorey prescribed fires as part of a comprehensive programme to understand fire and smoke behaviour. Instruments deployed on the ground, airplane and tethered aerostat platforms characterised the smoke plumes through measurements of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4) and particulate matter (PM), and measurements of optical properties. Distinctions were observed in aerial and ground-based measurements, with aerial measurements exhibiting smaller particle size distributions and PM emission factors, likely due to particle settling. Black carbon emission factors were similar for both burns and were highest during the initial flaming phase. On average, the particles from the forest fire were less light absorbing than those from the grass fires due to the longer duration of smouldering combustion in the forest biomass. CO and CH4 emission factors were over twice as high for the forest burn than for the grass burn, corresponding with a lower modified combustion efficiency and greater smouldering combustion. This dataset reveals the evolution of smoke emissions from two different commonly burned fuel types and demonstrates the complexity of emission factors.

scholarly journals Airborne measurements of fire Emission Factors for African biomass burning sampled during the MOYA Campaign

2020 ◽  
Author(s):  
Patrick A. Barker ◽  
Grant Allen ◽  
Thomas Bannan ◽  
Archit Mehra ◽  
Keith N. Bower ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Combustion Efficiency ◽  
Emission Factors ◽  
Airborne Measurements ◽  
Atlantic Seaboard ◽  
Trace Gas Emissions ◽  
Fire Plumes ◽  
Carbon Dioxide Co2 ◽  
Continental Outflow ◽  
Modified Combustion Efficiency

Abstract. Airborne sampling of methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), and nitrous oxide (N2O) mole fractions was conducted during field campaigns targeting fires over Senegal in February and March 2017, and Uganda in January 2019. The majority of fire plumes sampled were close to, or directly over burning vegetation, with the exception of two longer-range flights over the West African Atlantic seaboard, (100–300 km from source) where the continental outflow of biomass burning emissions from a wider area of West Africa was sampled. Fire Emission Factors (EFs) and modified combustion efficiencies (MCEs) were estimated from the enhancements in measured mole fractions. For the Senegalese fires, mean EFs and corresponding one-standard deviation variabilities, in units of g per kg of dry fuel were 1.8 (± 0.06) for CH4, 1633 (± 56.4) for CO2 and 679 (± 1.6) for CO, with a mean MCE of 0.94 (± 0.005). For the Ugandan fires, mean EFs (in units of g kg−1) were 3.1 (± 0.1) for CH4, 1610 (± 54.9) for CO2 and 78 (± 1.9) for CO, with a mean modified combustion efficiency of 0.93 (± 0.004). A mean N2O EF of 0.08 (± 0.002) g kg−1 is also reported for one flight over Uganda; issues with temperature control of the instrument optical bench prevented N2O EFs from being obtained for other flights over Uganda. This study has provided new datasets of African biomass burning EFs and MCEs for two distinct study regions, in which both have been studied little by aircraft measurement previously. These results highlight the important intracontinental variability of biomass burning trace gas emissions, and can be used to better constrain future biomass burning emission budgets. More generally, these results highlight the importance of regional and fuel-type variability when attempting to spatially scale biomass burning emissions. Further work to constrain EFs at more local scales and for more specific (and quantifiable) fuel types will serve to improve global estimates of biomass burning emissions of climate-relevant gases.

Burning California Chaparral - an Exploratory Study of Some Common Shrubs and Their Combustion Characteristics.

1991 ◽  
Vol 1 (3) ◽  
pp. 153 ◽  
Author(s):  
DR Weise ◽  
DE Ward ◽  
TE Paysen ◽  
AL Koonce
Keyword(s):  
Particulate Matter ◽  
Prescribed Fire ◽  
Exploratory Study ◽  
Combustion Efficiency ◽  
Emission Factors ◽  
Particulate Emissions ◽  
Scrub Oak ◽  
Adenostoma Fasciculatum ◽  
Carbon Dioxide Co2 ◽  
Co Emission

Prescribed fire is a tool used to manage vegetation in southern California. The nature and quan tity of gaseous and particulate emissions have not been described for California chaparral. A study examining carbon monoxide (CO), carbon dioxide (CO2), and par ticulate matter emissions from fuel beds constructed from common chaparral shrubs was initiated. Chamise (Adenostoma fasciculatum), ceanothus (Ceanothus crassifolius), manzanita (Arctostaphylos glandulosa), and scrub oak (Quercus dumosa) fuel beds were burned in December 1989, and March, May, and August, 1990. Gas and particulate matter samples were collected from 45 fires. Emission factors for CO2 and particulate matter were affected by species and month individually; month and species interacted and affected CO emission factors. Pearson's correlation coefficient and Kendall's tau indi cated that emission factors for CO and particulate matter were inversely related to combustion efficiency.

scholarly journals Emission factors of domestic coal-burning braziers

2017 ◽  
Vol Volume 113 (Number 3/4) ◽  
Author(s):  
Tafadzwa Makonese ◽  
Daniel M. Masekameni ◽  
Harold J. Annegarn ◽  
Patricia B.C. Forbes ◽  
◽  
...  
Keyword(s):  
South African ◽  
Emission Factors ◽  
Particle Sizes ◽  
Emission Rates ◽  
Coal Burning ◽  
Source Category ◽  
Pm2.5 And Pm10 ◽  
Ventilation Rates ◽  
Co Emission ◽  
Pm10 Emissions

Abstract We present experimental results of emission factors from a suite of domestic coal-burning braziers (lab fabricated and field collected) that span the possible range of real-world uses in the Highveld region of South Africa. The conventional bottom-lit updraft (BLUD) method and the top-lit updraft (TLUD) method were evaluated using coal particle sizes between 20 mm and 40 mm. Emission factors of CO2, CO and NOx were in the range of 98–102 g/MJ, 4.1–6.4 g/MJ and 75–195 mg/MJ, respectively. Particulate matter (PM2.5 and PM10) emissions were in the range 1.3–3.3 g/MJ for the BLUD method and 0.2–0.7 g/MJ for the TLUD method, for both field and lab-designed stoves. When employing the TLUD method, emission factors of PM2.5/PM10 reduced by up to 80% compared with those when using the BLUD method. Results showed the influence of ventilation rates on emission factors, which reduced by ~50% from low to high ventilation rates. For energy-specific emission rates, the combined (3-h) PM10 emission rates were in the range of 0.0028–0.0120 g/s, while the combined average CO emission rates were in the range of 0.20– 0.26 g/s, with CO2 emission rates in the range of 0.54–0.64 g/s. The reported emission factors from coal braziers provide the first comprehensive, systematic set of emission factors for this source category, and fill a major gap in previous efforts to conduct dispersion modelling of South African Highveld air quality.

scholarly journals Airborne measurements of fire emission factors for African biomass burning sampled during the MOYA campaign

2020 ◽  
Vol 20 (23) ◽  
pp. 15443-15459 ◽  
Author(s):  
Patrick A. Barker ◽  
Grant Allen ◽  
Martin Gallagher ◽  
Joseph R. Pitt ◽  
Rebecca E. Fisher ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Combustion Efficiency ◽  
Emission Factors ◽  
Airborne Measurements ◽  
Atlantic Seaboard ◽  
Trace Gas Emissions ◽  
Fire Plumes ◽  
Carbon Dioxide Co2 ◽  
Continental Outflow ◽  
Modified Combustion Efficiency

Abstract. Airborne sampling of methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), and nitrous oxide (N2O) mole fractions was conducted during field campaigns targeting fires over Senegal in February and March 2017 and Uganda in January 2019. The majority of fire plumes sampled were close to or directly over burning vegetation, with the exception of two longer-range flights over the West African Atlantic seaboard (100–300 km from source), where the continental outflow of biomass burning emissions from a wider area of West Africa was sampled. Fire emission factors (EFs) and modified combustion efficiencies (MCEs) were estimated from the enhancements in measured mole fractions. For the Senegalese fires, mean EFs and corresponding uncertainties in units of gram per kilogram of dry fuel were 1.8±0.19 for CH4, 1633±171.4 for CO2, and 67±7.4 for CO, with a mean MCE of 0.94±0.005. For the Ugandan fires, mean EFs were 3.1±0.35 for CH4, 1610±169.7 for CO2, and 78±8.9 for CO, with a mean modified combustion efficiency of 0.93±0.004. A mean N2O EF of 0.08±0.002 g kg−1 is also reported for one flight over Uganda; issues with temperature control of the instrument optical bench prevented N2O EFs from being obtained for other flights over Uganda. This study has provided new datasets of African biomass burning EFs and MCEs for two distinct study regions, in which both have been studied little by aircraft measurement previously. These results highlight the important intracontinental variability of biomass burning trace gas emissions and can be used to better constrain future biomass burning emission budgets. More generally, these results highlight the importance of regional and fuel-type variability when attempting to spatially scale biomass burning emissions. Further work to constrain EFs at more local scales and for more specific (and quantifiable) fuel types will serve to improve global estimates of biomass burning emissions of climate-relevant gases.

scholarly journals Analyzing the Renewable Energy and CO2 Emission Levels Nexus at an EU Level: A Panel Data Regression Approach

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 130
Author(s):  
Mihail Busu ◽  
Alexandra Catalina Nedelcu
Keyword(s):  
Renewable Energy ◽  
Panel Data ◽  
Co2 Emissions ◽  
Co2 Emission ◽  
Negative Impact ◽  
National Level ◽  
Renewable Energy Consumption ◽  
Urbanization Level ◽  
Carbon Dioxide Co2 ◽  
The Impact

In the past decades, carbon dioxide (CO2) emissions have become an important issue for many researchers and policy makers. The focus of scientists and experts in the area is mainly on lowering the CO2 emission levels. In this article, panel data is analyzed with an econometric model, to estimate the impact of renewable energy, biofuels, bioenergy efficiency, population, and urbanization level on CO2 emissions in European Union (EU) countries. Our results underline the fact that urbanization level has a negative impact on increasing CO2 emissions, while biofuels, bioenergy production, and renewable energy consumption have positive and direct impacts on reducing CO2 emissions. Moreover, population growth and urbanization level are negatively correlated with CO2 emission levels. The authors’ findings suggest that the public policies at the national level must encourage the consumption of renewable energy and biofuels in the EU, while population and urbanization level should come along with more restrictions on CO2 emissions.

Effects of Air Flowrate on the Combustion and Emissions of Blended Corn Straw and Pinewood Wastes

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Xiaoxiao Meng ◽  
Wei Zhou ◽  
Emad Rokni ◽  
Honghua Zhao ◽  
Rui Sun ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ignition Delay Time ◽  
Fixed Bed ◽  
Combustion Efficiency ◽  
Fixed Bed Reactor ◽  
Corn Straw ◽  
Excess Air ◽  
Burning Rates ◽  
Excess Air Coefficient ◽  
Hazardous Pollutants

This research investigated the effects of the specific primary (under-fire) air flowrate (m˙air) on the combustion behavior of a 50–50 wt % blend of raw corn straw (CS) and raw pinewood wastes in a fixed-bed reactor. This parameter was varied in the range of 0.079–0.226 kg m−2 s−1, which changed the overall combustion stoichiometry from air-lean (excess air coefficient λ = 0.73) to air-rich (excess air coefficient λ = 1.25) and affected the combustion efficiency and stability as well as the emissions of hazardous pollutants. It was observed that by increasing m˙air, the ignition delay time first increased and then decreased, the average bed temperatures increased, both the average flame propagation rates and the fuel burning rates increased, and the combustion efficiencies also increased. The emissions of CO as well as those of cumulative gas phase nitrogen compounds increased, the latter mostly because of increasing HCN, while those of NO were rather constant. The emissions of HCl decreased but those of other chlorine-containing species increased. The effect of m˙air on the conversion of sulfur to SO2 was minor. By considering all of the aforesaid factors, a mildly overall air-rich (fuel-lean) (λ = 1.04) operating condition can be suggested for corn-straw/pinewood burning fixed-bed grate-fired reactors.

scholarly journals Observations of atmospheric <sup>14</sup>CO<sub>2</sub> at Anmyeondo GAW station, South Korea: implications for fossil fuel CO<sub>2</sub> and emission ratios

2020 ◽  
Vol 20 (20) ◽  
pp. 12033-12045
Author(s):  
Haeyoung Lee ◽  
Edward J. Dlugokencky ◽  
Jocelyn C. Turnbull ◽  
Sepyo Lee ◽  
Scott J. Lehman ◽  
...  
Keyword(s):  
South Korea ◽  
Sulfur Hexafluoride ◽  
Fossil Fuel ◽  
Combustion Efficiency ◽  
Mean Value ◽  
Asian Continent ◽  
Air Masses ◽  
Air Samples ◽  
Carbon Dioxide Co2 ◽  
Emission Ratios

Abstract. To understand the Korean Peninsula's carbon dioxide (CO2) emissions and sinks as well as those of the surrounding region, we used 70 flask-air samples collected during May 2014 to August 2016 at Anmyeondo (AMY; 36.53∘ N, 126.32∘ E; 46 m a.s.l.) World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) station, located on the west coast of South Korea, for analysis of observed 14C in atmospheric CO2 as a tracer of fossil fuel CO2 contribution (Cff). Observed 14C ∕ C ratios in CO2 (reported as Δ values) at AMY varied from −59.5 ‰ to 23.1 ‰, with a measurement uncertainty of ±1.8 ‰. The derived mean value Cff of (9.7±7.8) µmol mol−1 (1σ) is greater than that found in earlier observations from Tae-Ahn Peninsula (TAP; 36.73∘ N, 126.13∘ E; 20 m a.s.l., 28 km away from AMY) of (4.4±5.7) µmol mol−1 from 2004 to 2010. The enhancement above background mole fractions of sulfur hexafluoride (Δx(SF6)) and carbon monoxide (Δx(CO)) correlate strongly with Cff (r>0.7) and appear to be good proxies for fossil fuel CO2 at regional and continental scales. Samples originating from the Asian continent had greater Δx(CO) : Cff(RCO) values, (29±8) to (36±2) nmol µmol−1, than in Korean Peninsula local air ((8±2) nmol µmol−1). Air masses originating in China showed (1.6±0.4) to (2.0±0.1) times greater RCO than a bottom-up inventory, suggesting that China's CO emissions are underestimated in the inventory, while observed RSF6 values are 2–3 times greater than inventories for both China and South Korea. However, RCO values derived from both inventories and observations have decreased relative to previous studies, indicating that combustion efficiency is increasing in both China and South Korea.

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