Elevated flares consist of a stack, flare tip, pilot burners, pilot ignition, and associated facilities for fuel gas and steam (Figure 15-1). The stack, which may be up to 183 m (600 feet) in height, can be self-supporting, attached to a derrick, or steadied with guy wires. An elevated flare is normally used for burning gases containing hydrogen sulfide, hydrocarbons and other corrosive or toxic fluids. Elevated flares provide the best dispersion of malodorous or toxic combustion products.
Disadvantages of an elevated flare are: exposure of plant personnel and facilities to radiant heat during a major release, noise, and annoyance of the public due to the visible flame. Despite its disadvantages, the elevated flare is the most common choice either for total flare loads, or for handling overcapacity releases in conjunction with a multiple burner (multijet) ground flare. For most applications, the elevated flare is the only acceptable means of flaring “dirty gases” that may result in evolution of particulates or corrosive compounds.
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