The use of physical properties of flare vent gas and the exit velocity have commonly been used to describe flame stability for flares. Multipoint ground flare burners, or pressure assisted flare burners, commonly used in the ethylene industry do not abide by the EPA mandated exit velocity criteria.
A review of available data reveals that neither combustion zone net heating value nor combustion zone flammability limit are good predictors of combustion efficiency for pressure-assisted flares. Statistics calculated from the data also indicate that the manufacture of the burner head is also significant to determining the combustion efficiency of the flare although all of the data available showed the burners outperformed current EPA requirements.
A new burner design with advantageous flame characteristics is presented along with flame stability and combustion efficiency data from physical testing for multiple burner types. Insight is gained thought computational fluid dynamic simulation of the designs.
A discussion of the practical implications of ancillary equipment, such as knock-out drums, will also be provided.