What is it about?

A Recent EPA rule requires an evaluation of visible emissions in terms of opacity in compliance with the standards. Presence of smoke (visible emissions) in the flare flame indicates incomplete combustion. ISP is the point of operation with little or no smoke. High combustion efficiency is achieved at ISP, with minimal air or steam assist. This phenomenon has not been rigorously quantified before. Importance of ISP is illustrated in this study because flare operators intend to add too much air or steam to suppress smoke to comply with smokeless flaring regulations by EPA. Therefore, this study characterized ISP in terms of significant operating parameters and in terms of performance variables. This helps the flare operators determine the appropriate range of parameters for efficient operation in compliance with the regulations. This study involved ISP test data collection, flame structure modeling, the optical path length, flame temperature, combustion zone volumetric flow, and soot concentration calculations. Beer-Lambert law was used to calculate opacity using optical length and soot concentration.

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Why is it important?

Incipient smoke is the initial smoke point of operation at which a little or no smoke is formed. At this point of operation, high combustion efficiency is achieved, with minimal air or steam assist. Despite the significance of the ISP at which efficient combustion takes place, the phenomenon has not been rigorously quantified before. Very few studies were performed earlier to characterize the incipient smoke point for flares based on soot yield, opacity, and other operating variables. 2. Equations developed in this study will help calculate the opacity or absorptivity or soot yield for steam/air and non-assisted flares, when any one of the variables is known or measured. This will help reduce the cost involved in sample analysis or expenses for monitoring equipment.


Overall, this study will help reduce flare emissions such as unburned hydrocarbons and black carbon (BC) or soot by using the optimum steam/ air assist and other operating parameters characterized at ISP, since control of smoke and VOC emissions from flaring are important issues from the environmental standpoint.

Lamar University

Read the Original

This page is a summary of: Characterization of the incipient smoke point for steam-/air-assisted and nonassisted flares, Journal of the Air & Waste Management Association, September 2018, Taylor & Francis,
DOI: 10.1080/10962247.2018.1525443.
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