Emission Factors for Biofuels and Coal Combustion in a Domestic Boiler of 18 kW

Abstract

The differences in the pollutant emissions from the combustion of bituminous coal and biofuels (wood, straw, and miscanthus pellets) under real-world boiler operating conditions were investigated. The experiments were performed on an experimental installation that comprised an 18 kW boiler, used in domestic central heating systems, equipped with a retort furnace, an automatic fuel feeder, a combustion air fan, and a fuel storage bin. The emission factors of gaseous pollutants, particulate matter, organic carbon, elemental carbon, and polycyclic aromatic hydrocarbons (PAHs), as well as some PAH concentration ratios for coal and biofuel combustion, were determined. The obtained results indicate that fuel properties have a strong influence on the emission factors of gaseous and carbonaceous pollutants. The total particulate matter (PM) emissions from the biofuel combustion were about 5-fold lower than those from the coal burned in the same boiler. The emission factors of the total carbons from the biofuel combustion were between 10 and 20 times lower than those from the coal combustion. The mean organic carbon (OC) and elemental carbon (EC) emission factors, based on the burned fuel, were 161–232 and 42–221 mg/kg for the biofuels and 1264 and 3410 g/kg for the coal, respectively. The obtained results indicate that molecular diagnostic ratios, based on the concentration of PAHs, vary significantly, depending on the fuel type.

Emissions of Gases and Volatile Organic Compounds from Residential Heating: A Comparison of Brown Coal Briquettes and Logwood Combustion

“…EFs in the literature vary largely, ,, and EFs found in the present study agree with earlier findings. For coal combustion in European appliances, Czaplicka et al reported EFs of approximately 190 mg MJ –1 , being approximately twice as high as EFs found here with 100 ± 10 mg MJ –1 , although the fuel-S content was comparable. Křůmal et al reported EFs of 143 to 658 mg MJ –1 for various coals and coal briquettes, with EFs of their brown coal briquettes being most comparable to EFs found in the present study.…”

“…For residential coal combustion, information on emissions from stoves relevant for European emission scenarios is scarce, since most of the research was focused on boilers, ,, which are generally larger and might have more efficient NO x reduction due to operational/technological aspects . To the authors’ knowledge, NO x EFs for coal combustion in stoves relevant for Europe were only reported for coal briquettes from various coals by Mitchell et al varying from 204 to 438 mg MJ –1 , which are clearly higher than any of the other EFs found for biomass.…”

“…To the best of the authors’ knowledge, only a few studies have investigated emissions from residential coal combustion in Europe, and these studies have mainly focused on effects of different boiler designs (old vs modern) and fuels (biofuels vs coal) on PM emissions. − It was found that old boilers emit up to two orders of magnitude more PM and polycyclic aromatic hydrocarbons (PAHs) than modern boilers . Also, emissions factors of organic markers for coal combustion, such as hopanes, were found to vary by two orders of magnitude depending on the boiler design .…”

Comparison of Carbonaceous Compounds Emission from the Co-Combustion of Coal and Waste in Boilers Used in Residential Heating in Poland, Central Europe

“…In the combustion processes of solid fuels or their mixtures, significant amounts of organic compounds, such as volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), phenols, and aliphatic compounds are emitted to the atmosphere as a result of incomplete combustion [13][14][15][16][17]. PAHs can naturally occur in coal and coal 2 of 15 combustion fly ashes [18][19][20].…”

“…Energies 2021, 14, x FOR PEER REVIEW 2 of 15 hydrocarbons (PAHs), phenols, and aliphatic compounds are emitted to the atmosphere as a result of incomplete combustion [13][14][15][16][17]. PAHs can naturally occur in coal and coal combustion fly ashes [18][19][20].…”