Flue gas Flue gas 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 (), and water vapor as well as excess oxygen (also derived from the combustion air). It further contains a small percentage of a number
Natural gas in the United States sealed with rope and molten lead. In the 1800s and early 1900s, most natural gas discoveries were made while exploring for oil. Natural gas was usually an unwanted byproduct of oil production. In the 1870s steel pipe replaced cast iron. In 1883, Pittsburgh became the first major city supplied with natural gas. Other cities followed, but only if they were close to natural gas wells. Because natural gas was a byproduct, it was priced cheaply, and, where available, undercut the market for town gas. In 1891, one of the longest pipelines of the time was built, a 120-mile long pipeline