ENV-13-24 Advances in Flare Performance Parameters

Description:

Historically, flare testing demonstrated that routine refinery flare operation could safely assume a 98% VOC Combustion Efficiency (CE). The operational parameters associated with flame stability and required by current EPA regulations to assess the veracity of the CE assumption are limited. Because of a shift in the awareness of proper flare operation regarding in part the use of assist gas, a continuous CE of 98% is no longer an automatic presumption. The degree of CE control cultivated over the past 30 years was based upon a few, simple, fixed parameters. However, new monitoring and measurement techniques are providing further insight, and an evolution of operational parameters, for consideration. Due to safety concerns and cost, it is not practical to continuously measure CE directly from open flame flares. Therefore, testing has been conducted to determine suitable system parameters to indicate or suggest the degree of CE in the combustion zone of the flare. A varying degree of correlation to CE exists among these parameters. For example, combustion zone net heating value (NHVcz) is one parameter that has been recently demonstrated to closely correlate to CE for steam-assist elevated flares. This paper is designed to introduce the evolution of flare performance parameters that have been considered over the past decade.