Flare Assist Gases

Searching for flare pilots, pilot gases, flare pilot systems, pilot ignitor systems and such might get you on the right track.

I was in operations for years in 2 east coast refineries. I never saw a flare system that utilized assist gasses. We did however have a good sized pilot flame at the top of each flare. The 3 flares operated in a "staged" manner. Each one had a water seal leg on it that had to be overcome before gasses could reach the flare to burn. The water legs were of 3 different heights. The seal leg operated in the same way a drain trap does. When a safety lifted and the flare header became pressurized the gasses lifted the water legs starting with the shortest one. A large dump would lift all 3 legs simultaneously and the sky would light up. We also utilized a centrifugal compressor that pulled suction on the flare header and routed the discharge to condensers to recover condensible liquids from the gas stream. The liquids were then sent to the slop tank and eventually injected into the feed and refined again. The flare header circled the refinery and was 50+ inches in diameter so that when a high pressure release happened the pressure was reduced to a few psi at most by the time it reached the flares. The flare header had several knockout drums along it's length and was pitched so any liquids would drain back to the drum. All flares need to be well elevated to prevent a release of H2S at ground level should a pilot light fail. At one time we had a ground level flare on the shortest seal leg but decommissioned it because of possible H2S issues. Ed

I work for a company that specializes in flare ignition systems. I'm currently in the design phase of a flare ignition system using an ultrasonic flow meter to ignite the flare when the escape reaches a certain velocity. This "non-standing pilot" type of flare requires me to predict escape gas content, BTU, etc, to provide the necessary "assist" prior to ignition each time. A company who shall remain nameless in this forum is developing the algorithms based on gmol for real time ident. But, since I'm igniting the thing each time I need it, I need to develop the best mixtures of assist gases and air. Hence the wording of my original Q. Thanks for your attention. Jim

oh,yes

gas assistant flares are endothermic flares which stream heat value is not enough for good combustion.the you need assist gas to rising LHV like some incinerators.

i worked in olefin plant and i dont see gas assistant flares but i was read in john zink handbook .