Flare systems in refineries and chemical plants are used to burn off flammable gases and hydrocarbons in plant upsets, shutdowns and start-ups. Flares allow for the safe, effective disposal of gases and liquids, by acting as relief devices when a plant must quickly dispose of product within its system to prevent over pressurization and potential explosions. Flares are used extensively in the hydro-carbon and petrochemical industries as a way to achieve safe and reliable vapor release. Governmental laws and regulations require the flare to be located a safe distance from the operating units and populated areas.
Whenever industrial plant equipment are over pressurized, the pressure relief valves, which are required by law, automatically release the gases. In a elevated flare, the gases are routed through flare headers, to a vertical elevated flare. The released gases are then burned off as they exit the flare stacks. As the gases or hydrocarbons are burned off, steam is added to the flare, to enhance oxygen, so the flare burns more efficiently.
You may sometimes see black smoke coming from the flame. This occurs when an insufficient amount of steam is available to help burn the hydrocarbons sent to the flare. In order to keep the flare system functional, a small amount of gas is continuously burned, so that the system is always ready for its primary purpose as an over-pressure safety system.
Flare stacks range in height from 200 to 350 feet. A self-supporting flare stack looks like a large perpendicular pipe, usually with graduated size, and has a burner at the top. Some of the smaller stacks have guy wires for protection against high winds. Derrick support many smaller flare stacks.
Another type of flare would be the ground flare. This type of flare is a completely enclosed flare system in which combustion occurs inside an insulated flare stack and in a controlled environment. The enclosed ground flare destroys a waste stream, but does not maintain a...
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