Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying Exhaust gas, as from a fireplace, oven, furnace, boiler or steam generator. It often refers to the exhaust gas of combustion at Power plant. Technology is available to remove pollutants from flue gas at power plants.
Combustion of Fossil fuel is a common source of flue gas. They are usually combusted with ambient air, with the largest part of the flue gas from most Fossil fuel combustion being nitrogen, carbon dioxide, and water vapor.
Technologies based on regenerative capture by amines for the removal of from flue gas have been deployed to provide high purity gas to the food industry, and for enhanced oil recovery. They are now under active research as a method for capture for long-term storage as a means of greenhouse gas remediation, and have begun to be implemented in a limited way commercially (e.g. the Sleipner West field in the North Sea, operating since 1996).
There are a number of proven technologies for removing pollutants emitted from power plants that are now available. There is also much ongoing research into technologies that will remove even more air pollutants.
A typical flue gas from the combustion of fossil fuels contains very small amounts of (), sulfur dioxide (SO2) and particulate matter. Fossil fuel combustion flue gases Milton R. Beychok, Encyclopedia of Earth, 2012. The nitrogen oxides are derived from the nitrogen in the ambient air, as well as from any nitrogen-containing compounds in the fossil fuel. The sulfur dioxide is derived from any sulfur-containing compounds in the fuels. The particulate matter is composed of very small particles of solid materials and very small liquid droplets which give flue gases their smoky appearance.
The steam generators in large and the process furnaces in large Oil refinery, petrochemical and , and burn considerable amounts of fossil fuels and therefore emit large amounts of flue gas to the ambient atmosphere. The table below presents the total amounts of flue gas typically generated by the burning of fossil fuels such as natural gas, fuel oil and coal. The data were obtained by Stoichiometry calculations.Citation error. See inline comment how to fix.
The total amount of wet flue gas generated by coal combustion is only 10 percent higher than the flue gas generated by natural-gas combustion (the ratio for dry flue gas is higher).
+Exhaust flue gas generated by combustion of fossil fuels (In SI metric units and in US customary units) ! align="left" | Combustion data ! align="right" | Fuel gas ! align="right" | Fuel oil ! align="right" | Coal |
Heating value, MJ/m3 | 43.01 | |||
Heating value, Btu/scf | 1,093 | |||
Gross caloric value, MJ/kg | 43.50 | |||
Gross heating value, Btu/gal'' | 150,000 | |||
Gross caloric value, MJ/kg | 25.92 | |||
Gross heating value, Btu/lb | 11,150 | |||
Molecular mass | 18 | |||
Relative density | 0.9626 | |||
API gravity, °API | 15.5 | |||
Carbon/hydrogen ratio by weight | 8.1 | |||
weight % carbon | 61.2 | |||
weight % hydrogen | 4.3 | |||
weight % oxygen | 7.4 | |||
weight % sulfur | 3.9 | |||
weight % nitrogen | 1.2 | |||
weight % ash | 12.0 | |||
weight % moisture | 10.0 | |||
Excess combustion air, % | 12 | 15 | 20 | |
Amount of wet exhaust gas, m3/GJ of fuel | 294.8 | 303.1 | 323.1 | |
Amount of wet exhaust gas, scf/106 Btu of fuel | 11,600 | 11,930 | 12,714 | |
in wet exhaust gas, volume % | 8.8 | 12.4 | 13.7 | |
O2 in wet exhaust gas, volume % | 2.0 | 2.6 | 3.4 | |
Molecular weight of wet exhaust gas | 27.7 | 29.0 | 29.5 | |
Amount of dry exhaust gas, m3/GJ of fuel | 241.6 | 269.3 | 293.6 | |
Amount of dry exhaust gas, scf/106 Btu of fuel | 9,510 | 10,600 | 11,554 | |
CO2 in dry exhaust gas, volume % | 10.8 | 14.0 | 15.0 | |
O2 in dry exhaust gas, volume % | 2.5 | 2.9 | 3.7 | |
Molecular weight of dry exhaust gas | 29.9 | 30.4 | 30.7 |
|
|