Modeling and Velocity Measurements at the Burner Throat: The Relationship to Performance in a Model Industrial, Natural Gas Fired Burner

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Modeling and Velocity Measurements at the Burner Throat: The Relationship to Performance in a Model Industrial, Natural Gas Fired Burner M. M. Miyasato and G. S. Samuelsen UCI Combustion Laboratory University of California, Irvine Irvine, CA 92697-3550 USA Emissions measurements of a model, industrial burner have shown that a particular fuel delivery strategy produces superior perfonnance in tenns of high combustion efficiency and low NOx when operated with strategic fuel and air mixing scenarios. Previous non-intrusive laser measurements have quantified the temperature and NO flow-field downstream of the burner quarl exit and have suggested that important features of the burner perfonnance reside in the near field of the fuel injection. To better understand the perfonnance of the burner laser anemometry and CFD modeling were conducted at the burner throat. The results identify subtle but significant differences in the early stages of the fuel injection that affect the burner performance. INTRODUCTION Due to increasingly stringent air quality regulations, industrial burners are required to emit lower and lower levels of nitrogen oxides (NOx), carbon monoxide (CO), and unburned hydrocarbons (HC's). These regulations are especially strict in southern California where the prevailing atmospheric conditions and high population density combine to produce a major urban air quality challenge [1]. Nitrogen oxides, which consist of nitric oxide (NO) and nitrogen dioxide (N02), are emitted from all air-breathing combustion systems and are important due to their role in photochemical oxidant, more commonly known as "smog," formation. Although the automobile is the most dominant emitter of NOx, stationary sources contribute a large amount. In the southern California air basin, industrial sources account for approximately 250/0 of the oxidant formed [2]. To reduce NOx emissions from industrial burners, "cleaner" fuels have been employed. For example, natural gas is required at all industrial sites in southern California. However, even when burning natural gas, which is considered the cleanest fossil fuel, copious amounts of NOx can still be emitted. Current methods of NOx control have typically relied on post-combustion control, off­stoichiometric combustion, or internal flue gas recirculation methods [3]. Low NOx burner technologies, which currently rely on empirical, trial-and-error, or case-specific fuel and air