An Experimental Study of the Effects of Waste-Gas Composition and Crosswind on Non-assisted Flares Using a Novel Indoor Testing Approach

Non-assisted flares are a significant fraction of the flares in use today, but there are few studies at real-world conditions. The current work presents a novel indoor testing facility for characterizing non-assisted flares including the effects of crosswind. Multiple flare designs were tested using flare gas flow rates from 1.8 to 113 thousand standard cubic feet per day (MSCFD) with natural gas and propane at crosswind speeds from 0 to 13.1 miles per hour (MPH). Combustion efficiency (CE) and destruction removal efficiency of methane (DRE_CH4) were determined for all operating conditions. CE > 98% was observed for low crosswind conditions for all flare geometries; however, the 3-in. pipe flare underperformed (CE < 96.5%) for natural gas at higher wind speeds and lower flare gas flow rates (e.g., 6.8 MSCFD and >4.6 MPH). Engineered burners significantly improved performance. The results are discussed in the context of EPA assumptions, prior pipe flare wind-tunnel studies, and proposed scaling relations.