API Std 537:2003 pdf download
API Std 537:2003 pdf download.Flare Details for General Refinery and Petrochemical Service.
Liquids shall be removed sufliciently to prevent poor cornbustion, burning liquid droplets, and clogging of the flare burners.
4.6.1.4 Air inlilitation:
Air infiltration into the system can cause internal coinbus tion within the riser. It can cause flashback.
4.6.1.5 Flame radiation:
Flame radiation can cause damage or injury to nearby equipilient. sti ucluies aid pci sound.
4.6.1.6 Smoke suppression:
Smoke suppression may be required where environmental or aesthetic considerations warrant.
4.6.1.7 Flare gas recovery:
A portion of the waste stream can be recycled to the plant fuel gas system after compression.
4.6.1.8 Noise and visible light:
Noise and visible light should be limited to permitted leels. System design should address neighbors concerns in this area.
4.6.1.9 Refer to API Recommended Practice 521. (iiiiIc br Prc’ssuv Rctic’itng zn1 Dcpncstiriziiig Svsiens for addi – tional flare system design considerations and criteria.
5 Elevated Flare Equipment Components
5.1 FLARE BURNER
5.1.1 Purpose
Its design must provide for the safe discharge of the maxiie! floW rates at the system allowable
combustion. The flare burner ignites and combusts vapors
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conditions. This mechanical device must control the combustion process for the specified relief conditions, and must produce the desi red destruction/combustion eli ic lency. ‘I ‘he mechanical components of typical flare buruier designs arc described in this section.
5.1.2 Unassisted Pipe Flare
An unassisted pipe flare is uscd where smokeless burning assist is not required. Ignition of the flare flame is by pilots. Ibe pilots are ignited by a pilot ignition system.
The pipe flare burner may have a mechanical device or other means of establishing and maintaining a stable flame. The ignition tire from the gas discharge is initially ignited by inemction with (he pilot(s) flames. Once the pilot lights the flare siahiliiing flame, the flare should maintain flame stability over the operating design range.
Some flares are subject to regulations that limit exit velocity. For example. when Pipe Flares are applied in the USA as Control Technology for VOC emissions, the gas exit velocity may be limited by 40. The exit eIocity per 40 FR 60. 1 8 is a function ol flare gas properties. It is important to note that there are many flare applications that do not involve VOC control. Such flares are not required to meet the exit velocity requirements of the R.
The flame produced by an unassisted pipe flare will be a function of the relief gas composition and the gas exit velocity. At higher gas velocities, the gas discharge energy will pull combustion air into the flame, and will produce a shorter more erect (lame that has greater resistance to wind clefleclions. At lower gas exit velocities, air will primarily be drawn to the flame by the buoyancy of the heated products of combustion. A buoyant flame is typically softer, longer and more wind affected than a flaiiie that uses higher gas exit velocities.
I ow gas exit velocities and buoyancy dominated flames may be employed for successful combustion of lo heating value relief gas conditions. high gas exit vekwities can be employed for hydrocarbon relief gases of higher heating value or for relief gases rich in hydrogen content.
flare combustion noise is influenced by gas exit velocity. Increased relief gas exit velocity can produce greater combustion turbulence and have higher combusion noise levels. The highest combustion noise levels are reali,d when a flare burner is allowed to operate at a gas exit velocity where combustion instabilities occur. Combustion instability is defined as a flame that lights, lifts off. goes out and re-ignites in a semi-cyclic mode.
Tne prime operating concerns with unassisted pipe flares are that the relief gas discharging from the flare burner must occur within ihe hydraulic design or die flare sysielu (within the allowable pressure drop. and flame combustion v Wind acfions a low Iftiring rates can produce internal burning andior external flames that remain attached to the flare bunier. The flare burner should be designed to withstand thesuch internal and attached external burning. On larger sic flare burners. internal refractory linings arc sometimes employed to mitigate the thermal effects of internal burning.
