In many gas plant, flares are always installed to burn waste gases containing combustible components, such as methane, carbon monoxide, and hydrogen. The waste gases are piped to a remote, usually elevated location, and burned in open flame in ambient air using a specially designed burner tip, auxiliary fuel, and in some cases, assist gases like steam or air to promote mixing for nearly complete.

As mentioned in several posts, combustion requires three ingredients: fuel, an oxidizing agent (typically oxygen in air), and heat (or ignition source).

Flare Purge Gas and Flare Sweep Gas

In flare system, a pipe connection for purging or sweeping purpose is usually installed. Flare purge gas means gas introduced between a flare header’s water seal and the flare tip to prevent oxygen infiltration (backflow) into the flare tip. For a flare with no water seal, the function of flare purge gas is performed by flare sweep gas.

Flare sweep gas means the gas intentionally introduced into the flare header system to maintain constant flow of gas through the flare header to prevent oxygen build up in the flare header. Read More