| Abstract from DBPedia | Flue gas is the gas exiting 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, the flue gas refers to the combustion exhaust gas produced at power plants. 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 of air, carbon dioxide (CO2), and water vapor as well as excess oxygen (also derived from the combustion air). It further contains a small percentage of a number of pollutants, such as particulate matter (like soot), carbon monoxide, nitrogen oxides, and sulfur oxides. Most fossil fuels are combusted with ambient air (as differentiated from combustion with pure oxygen). Since ambient air contains about 79 volume percent gaseous nitrogen (N2), which is essentially non-combustible, the largest part of the flue gas from most fossil-fuel combustion is uncombusted nitrogen. Carbon dioxide (CO2), the next largest part of flue gas, can be as much as 10−25 volume percent or more of the flue gas. This is closely followed in volume by water vapor (H2O) created by the combustion of the hydrogen in the fuel with atmospheric oxygen. Much of the 'smoke' seen pouring from flue gas stacks is this water vapor forming a cloud as it contacts cool air. A typical flue gas from the combustion of fossil fuels contains very small amounts of nitrogen oxides (NOx), sulfur dioxide (SO2) and particulate matter. 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 power plants and the process furnaces in large refineries, petrochemical and chemical plants, and incinerators 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 stoichiometric calculations. 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).煙道ガス （えんどうガス）は、により大気中へ排出するガスで、煙道はパイプやチャンネルからなり、暖炉、オーブン、やボイラ や からガスを排出するものである。煙道ガスは発電所で発生する燃焼ガスとして使われることが多い。何を燃焼したかにより排ガス組成は変わるが、通常燃焼空気からの窒素 (2/3以上を占める)、二酸化炭素、 水蒸気と燃焼後の余剰の酸素 からなる。更に、粒子状物質 (すす等)、 一酸化窒素、窒素酸化物、硫黄酸化物等の汚染物質が少量含まれている。 (Source: http://dbpedia.org/resource/Flue_gas) |
