Flares are used in oil and gas operations in production and processing operations for either intermittent and/or continuous waste gas disposal. Continuous flaring is severely restricted in most regions and may include disposal of associated gas at remote oil production facilities where gas recovery is uneconomical. Intermittent applications are the more common scenario at refineries and gas plants. Here, flare systems are used both for safety reasons during upset processes (start-up, shut down, system blow-down) and in the management of waste gases from routine operations. There are significant gaps in predicting the nature and emission rate of flared gas, which results in difficulty in predicting downwind concentrations of pollutants. This uncertainty increases when coupled with the fact that most commercially available dispersion models are designed for continuous sources (such as compressor stacks or incinerators) rather than intermittent sources such as flares.
Numerical analysis tools that can correctly predict the behaviour of flare systems when subject to complex fuel compositions and meteorological conditions are desired. Martec Limited is actively involved in the offshore oil and gas industry and identified flare modeling as an area of interest in 2008. Of particular interest was that the non-steady flaring accounted for up to 1/3 of the flaring incidents, which is not modeled well with current modeling tools and yet has an impact on the operations of the facility. Our work would focus on the dynamic issue of flaring events and dispersion modeling, and the variable nature of the composition of the flared gas. A computational fluid dynamics model that would better predict the flame behaviour in flare stacks will be developed and implemented.