Flue gas
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2008-03-12T17:21:38Z
Sceptre
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Reverted 1 edit by [[Special:Contributions/12.240.51.54|12.240.51.54]] to last version by Puchiko
'''Flue gas''' is [[gas]] that exits to the atmosphere via a [[flue]], which is a pipe or channel for conveying exhaust gases from a fireplace, oven, [[furnace]], [[boiler]] or [[steam generator]]. Quite often, it refers to the [[combustion]] exhaust gas produced at [[power plant]]s. Its composition depends on what is being burned, but it will usually consist of mostly [[nitrogen]] (typically more than two-thirds) derived from the combustion air, [[carbon dioxide]] (CO<sub>2</sub>) and [[water vapor]] as well as excess [[oxygen]] (also derived from the combustion air). It further contains a small percentage of pollutants such as [[particulate matter]], [[carbon monoxide]], [[nitrogen oxides]] and [[sulfur oxides]].
At power plants, flue gas is often treated with a series of chemical processes and [[scrubber]]s, which remove pollutants. [[Electrostatic Precipitator|Electrostatic precipitators]] or fabric filters remove particulate matter and [[flue gas desulfurization]] captures the [[sulfur]] dioxide produced by burning fossil fuels, particularly coal. Nitrogen oxides are treated either by modifications to the combustion process to prevent their formation, or by high temperature or catalytic reaction with ammonia or urea. In either case, the aim is to produce nitrogen gas, rather than nitrogen oxides. In the US there is a rapid deployment of technologies to remove mercury from flue gas - typically by adsorption on sorbents or by capture in inert solids as part of the flue gas desulfurization product.
Technologies based on regenerative capture by amines for the removal of CO<sub>2</sub> from flue gas have been deployed to provide high purity gas to the food industry. They are now under active research as a method for CO<sub>2</sub> capture for long-term storage as a means of greenhouse gas remediation.
There are a range of emerging technologies for removing pollutants emitted from power plants. As yet, there is very little performance data available from large-scale industrial applications of such technologies and none has achieved significant penetration of the enormous worldwide market. <br><br>
==See also==
* [[Combustion]]
* [[Emission standard]]
* [[Exhaust gas]]
* [[Flue gas emissions from fossil fuel combustion]]
* [[Flue gas stacks]]
* [[Flue gas desulfurization]] (often referred to as FGD)
* [[Integrated Gasification Combined Cycle]] (often referred to as IGCC)
* [[Nitrogen oxide]]s emission (often referred to as NOx)
[[Category:Air pollution]]
[[Category:Chemical engineering]]
[[Category:Combustion]]
[[Category:Environmental engineering]]
[[de:Rauchgas]]
[[eo:Fumgaso]]
[[sv:Rökgas]]
[[uk:Димовий газ]]
[[zh:烟气]]