Combustion of Fuels - Carbon Dioxide Emission

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

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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

q_CO2 = c_f / h_f M_CO2/M_m [1]

where

q_CO2 = specific CO₂ emission [kg_CO2/kWh]
c_f = specific carbon content in the fuel [kg_C/kg_fuel]
h_f = specific energy content in the fuel [kWh/kg_fuel]
M_C = Molecular weight Carbon [kg/kmol Carbon]
M_CO2 = 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.

For full table with Specific CO2 emission - rotate the screen!

Fuel	Liquid density	Specific carbon content	Specific Energy content		Specific CO₂ emission (amount of fuel basis)			Specific CO₂ emission (amount of energy basis)
Fuel	kg/l	kg_C/kg_fuel	kWh/kg_fuel	Btu/lb_fuel	Kg_CO2/kg_fuel	Kg_CO2/gal_fuel	lb_CO2/gal_fuel	kg_CO2/kWh	kg_CO2/GJ	lb_CO2/mill Btu
Methane (natural gas)		0.75	15.4	23900	2.75			0.18	50	115
Propane	0.510	0.82	13.8	21300	2.99	5.78	12.7	0.22	60	140
Butane	0.564	0.83	13.6	21100	3.03	6.47	14.3	0.22	62	144
LPG (wt of C3=C4)	0.537	0.82	13.7	21200	3.01	6.12	13.5	0.22	61	142
Gasoline	0.737	0.90	12.9	19900	3.30	9.20	20.3	0.26	71	165.3
Kerosene (Jet)	0.821	0.82	12.0	18500	3.00	9.33	20.6	0.25	70	162.5
Diesel	0.846	0.86	12.7	19605	3.15	10.1	22.3	0.25	69	160.8
Heavy fuel oil (No.6/Bunker C)	0.980	0.85	11.6	18000	3.11	11.6	25.5	0.27	75	173.3
Petroleum coke		0.89	9.4	14500	3.26	14.7	32.4	0.35	97	225.1
Coal:										227.3
Anthracite		0.92	9.0	14000	3.37			0.37	104	229.5
Bituminous		0.65	8.4	13000	2.38			0.28	79	231.7
Subbituminous		0.4	6.8	10500	1.47			0.22	60	233.9
Lignite		0.3	3.9	6000	1.10			0.28	79	236.1
Coke		0.77	7.2	11200	2.82			0.39	108	251.5
Peat (dry)¹⁾		0.52	4.7	7300	1.91			0.40	112	260.7
Ethanol fuel (E100)²⁾	0.789	0.52	8.3	12800	1.91	5.71	12.6	0.23	64	149.6
Methanol fuel (M100)²⁾	0.791	0.37	5.5	8500	1.37	4.11	9.1	0.25	70	162.2
Biodiesel (B100)²⁾	0.880	0.78	11.3	17400	2.85	9.48	20.9	0.25	70	162.8
Wood ¹⁾ ²⁾		0.50	4.5	7000	1.83			0.41	113	263.1
Bio energy²⁾								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.