Products and Industries

Elevated/Open, Air/Steam Assist Flares
Enclosed Flare Systems

Gas Production, BTEX, H2S, Low BTU Flares

Thermal Oxidizers

Loading Terminal Flares/Vapor Combustors

Basic Elevated Flare Design Considerations
Per 40 CFR 60 AP 42 TCEQ

Over 100 years experience designing flares!


Flares must always have a minimum heat content in btu/scf:
  • Steam-assisted - 300 btu/scf
  • Air-assisted - 300 btu/scf
  • Non-assisted - 200 btu/scf
  • Tip exit velocity is limited based on BTU content in the flare stream.
  • Tip exit velocity is the velocity of the gas stream at the point where it exits the flare tip, not in the flare header itself.


Steam-assisted and non-assisted flares:
  • 300 Btu/scf = 60 fps maximum
  • Greater than 1,000 btu/scf = 400 fps maximum


Steam-assisted and non-assisted flares:
  • Log10(Vmax)=(HT+28.8)/31.7
  • Vmax=maximum velocity (m/sec)
  • (note: never exceed 400 fps)
  • HT=net heating value (MJ/scm)


Air-assisted flares:
  • Vmax=8.706 +0.7084(HT)
  • Vmax=maximum velocity (m/sec)
  • HT=net heating value MJ/scm

Types of flare pilot monitors include (all flares must have a continuous pilot when in operation):
  • Thermocouple
  • IR scanner
  • Video camera


Open elevated flare system testing:
  • Sample at inlet to flare stack
  • Measure flow rate to the flare
  • Sample and determine Btu content
  • 98% Destruction efficient by definition


Low BTU Gas - enrich before sampling point and prove enrichment by:
  • Fixed ratio injection assuming 0 BTU content
  • On line monitoring and gas control






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MRW Technologies, Inc.
2301 West 171st Street S | Glenpool | OK | 74033
PH: 918.827.6030 | FX: 918.827.6034 | EM: mrw@mrw-tech.com
Web: www.mrw-tech.com