The tip decides how the gas burns; the stack decides where the heat goes. Together they set flame length, radiation at grade, noise at the fence line and how much purge gas you will pay for every day of the plant's life.
Techso sizes flare tips and stacks to API 537 starting from the relief loads, and carries the result through to the radiation contours and the structural verification — so that the height on the drawing is the height the calculations actually require.
Selecting the burner
The choice is driven by the available pressure at the tip, the turndown between normal purge and the design release, and whether smokeless operation is required.
- Pipe flare — simple, robust, no smoke suppression
- Sonic and high-pressure tips — short flame, high turndown, pressure required
- Steam-assisted — smokeless, steam consumption and noise to be managed
- Air-assisted — smokeless where steam is unavailable, blower power required
- Enclosed ground flare — no visible flame, no radiation at grade, large footprint
Sizing criteria
- Exit velocity expressed as Mach number, for continuous and for the design release
- Flame stability and blow-off at the upper end of the range
- Purge velocity to prevent air ingress and internal burning
- Gas composition: lower heating value, molecular weight, hydrogen content
- Material selection and tip life at flame temperature
Flame geometry
Flame length follows from the heat release; flame tilt follows from the wind. The position of the flame centre is what the radiation calculation actually uses, and it moves with every wind speed considered.
- Flame length from heat release and gas properties
- Flame distortion and tilt across the range of design wind speeds
- Flame centre position, as input to the radiation model
System components
- Knock-out drum sizing for the droplet size that must not reach the tip
- Liquid seal drum — flashback protection and purge gas reduction
- Molecular or velocity seal at the top of the stack
- Pilots, flame detection and ignition system
- Purge gas selection and continuous consumption
What you receive
- Tip sizing calculation and datasheet for enquiry
- Stack height derived from the radiation and dispersion criteria
- Knock-out drum and seal drum sizing
- Technical evaluation of vendor proposals