Combustion of Fuels - Carbon Dioxide Emission

Environmental emission of carbon dioxide CO2 when combustion fuels like coal, oil, natural gas, LPG and bio energy

To calculate the Carbon Dioxide - CO2 - emission from a fuel, the carbon content of the fuel must be multiplied with the ratio of molecular weight of CO2 (44) to the molecular weight of Carbon (12) -> 44 / 12 = 3.7

Carbon Dioxide emission from burning a fuel can be calculated as

qCO2 = cf / hf  MCO2 /Mm                        [1]

where

qCO2 = specific CO2 emission [kgCO2/kWh]
cf = specific carbon content in the fuel [kgC/kgfuel]
hf = specific energy content in the fuel [kWh/kgfuel]
MC = Molecular weight Carbon [kg/kmol Carbon]
MCO2 = Molecular weight Carbon Dioxide [kg/kmol CO2]

Emission of CO2 from combustion of some common fuels are indicated in the table below.

Note! Heat loss - 55-75% - in power generation is not included in the numbers.

See also Heat of combustion, Fuels - Higher and Lower Calorific Values and Fossil and alternative fuels - energy content.

Fuel Liquid density Specific
carbon content
Specific
Energy content
Specific CO2 emission
(amount of fuel basis)
Specific CO2 emission
(amount of energy basis)
kg/l kgC/kgfuel kWh/kgfuel Btu/lbfuel KgCO2/kgfuel KgCO2/galfuel lbCO2/galfuel kgCO2/kWh kgCO2/GJ lbCO2/mill Btu
Methane
(natural gas)
0.75 15.4 23900 2.75 0.18 49.6 115
Propane 0.510 0.82 13.8 21300 2.99 5.78 12.7 0.22 60.4 140
Butane 0.564 0.83 13.6 21100 3.03 6.47 14.3 0.22 61.7 144
LPG
(wt of C3=C4)
0.537 0.82 13.7 21200 3.01 6.12 13.5 0.22 61.0 142
Gasoline 0.737 0.90 12.9 19900 3.30 9.20 20.3 0.26 0.071 165.3
Kerosene (Jet ) 0.821 0.82 12.0 18500 3.00 9.33 20.6 0.25 0.070 162.5
Diesel 0.846 0.86 12.7 19605 3.15 10.1 22.3 0.25 0.069 160.8
Heavy fuel oil
(No.6/Bunker C)
0.980

0.85

11.6 18000 3.11 11.6 25.5 0.27 0.075 173.3
Petroleum coke 0.89 9.4 14500 3.26 14.7 32.4 0.35 0.097 225.1
Coal: 0.000 227.3
Anthracite 0.92 9.0 14000 3.37 0.37 0.104 229.5
Bituminous 0.65 8.4 13000 2.38 0.28 0.079 231.7
Subbituminous 0.4 6.8 10500 1.47 0.22 0.060 233.9
Lignite 0.3 3.9 6000 1.10 0.28 0.079 236.1
Coke 0.77 7.2 11200 2.82 0.39 0.108 251.5
Peat (dry)1) 0.52 4.7 7300 1.91 0.40 0.112 260.7
Ethanol fuel (E100)2) 0.789 0.52 8.3 12800 1.91 5.71 12.6 0.23 0.064 149.6
Methanol fuel (M100)2) 0.791 0.37 5.5 8500 1.37 4.11 9.1 0.25 0.070 162.2
Biodiesel
(B100)2)
0.880 0.78 11.3 17400 2.85 9.48 20.9 0.25 0.070 162.8
Wood 1) 2) 0.50 4.5 7000 1.83 0.41 0.113 263.1
Bio energy 2) 0 2)

1) Commonly viewed as a Bio fuel.
2) Bio Energy is produced from biomass derived from any renewable organic plant, including

  • dedicated energy crops and trees
  • agricultural food and feed crops
  • agricultural crop wastes and residues
  • wood wastes
  • aquatic plants
  • animal wastes
  • municipal wastes and other waste materials

Emissions of CO2 can contribute to climate change. Combustion of bio energy don't add to the total emission of carbon dioxide as long as the burned bio mass don't exceed the renewed production (within a reasonable time), or it is not transformed in processes requiring CO2-forming energy. The recycling of carbon from wood combustion is virtually instantaneous and continuous and it is also common to regard the net supply of CO2 to the atmosphere from combustion of wood close to zero.

If the time of renewed production of the organic material is long (typically 50 year++), the the positive climate effect can be questioned. The renewed production rate of wood and peat varies with geography and climate.

A variety of bio fuels can be made from bio mass resources, including

  • ethanol
  • methanol
  • biodiesel
  • Fischer-Tropsch diesel
  • gaseous fuels like hydrogen or methane

Production of all these bio fuels requires energy, and the total CO2 gain depend on how much CO2-releasing energy that is necessary to transform the bio mass to bio fuel. Biodiesel production via Fischer-Tropsch synthesis is typically a high energy demanding process, and the CO2 gain compared to conventional diesel is low if the processing is run with energy with high CO2 emissions.

Related Topics

  • Environment - Climate, meteorology, sun, wind and environmental resources
  • Combustion - Boiler house topics - fuels like oil, gas, coal, wood - chimneys, safety valves, tanks - combustion efficiency
  • Material Properties - Material properties for gases, fluids and solids - densities, specific heats, viscosities and more

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