Flare stacks are employed by petrochemical plants, natural gas processing facilities, and chemical plants and refineries. They serve to burn off flammable gases released by pressure release valves as well as planned burns over short periods for plant start-ups or shutdowns. Combustion of vent gas is often more environmentally friendly than releasing the gas into the air, for example if methane is burnt the products are CO2 and water, which are less harmful to the environment than the methane.<\/p>\n
Oxygen analysis is required both at the burner and at the flare header to prevent build-ups of oxygen that may cause an unwanted explosion that could cause serious damage to the plant. At the flare header, gases from many points in the plant meet and oxygen levels should be kept below 0.1% which necessitates low-level detection and accuracy. At the burner itself oxygen should be kept below 1%.<\/p>\n