Analysis of Combustion Efficiencies for Industrial Steam-Assisted Flares

Paper from the AFRC 2013 conference titled Analysis of Combustion Efficiencies for Industrial Steam-Assisted Flares by Kevin Marr

Flares are essential in safely managing excess combustible gases that can result from normal operations as well as process upsets and emergency conditions in refineries, chemical plants, and other industrial facilities. In many modern flare designs, steam or air is added to the vent gas to suppress visible emissions per EPA regulations. Several studies have shown that operating flares with too much steam addition can reduce hydrocarbon combustion efficiencies. However, the current EPA regulations do not address the influence of steaming on flare performance. Recently, EPA directed test campaigns to measure combustion efficiencies for industrial-scale flares at several facilities throughout the country. This work analyzes the results from the EPA-directed flare test campaigns. The analysis investigates the effect of vent gas composition, in particular hydrogen concentration, and steam flow on combustion efficiency. Existing methods for estimating combustion efficiency are reviewed and a prediction methodology based on a Monte Carlo method that makes direct use of the test campaign data in the form of a look-up table is proposed.